Title of Invention	"AN IMPROVED PROCESS FOR THE LIQUID PHASE ACYLATION OF AROMATIC COMPOUNDS"
Abstract	The present invention relates to an improved process for the liquid phase acylation of aromatic compounds by an acylating agent using a solid catalyst comprising metal oxide(s). In the process acylation of aromatic compounds is carried out using a reusable solid catalyst comprising metal oxide(s). The process is liquid phase for the acylation of aromatic compounds including those which do not contain electron donating groups, using a solid catalyst with high activity when the aromatic ring activating groups like alkyl, alkoxy,hydroxyl,phenoxy are present in the aromatic ring to be acylated and also when the ring activating groups in the aromatic ring to be acylated are absent.

Title of Invention

"AN IMPROVED PROCESS FOR THE LIQUID PHASE ACYLATION OF AROMATIC COMPOUNDS"

Abstract

The present invention relates to an improved process for the liquid phase acylation of aromatic compounds by an acylating agent using a solid catalyst comprising metal oxide(s). In the process acylation of aromatic compounds is carried out using a reusable solid catalyst comprising metal oxide(s). The process is liquid phase for the acylation of aromatic compounds including those which do not contain electron donating groups, using a solid catalyst with high activity when the aromatic ring activating groups like alkyl, alkoxy,hydroxyl,phenoxy are present in the aromatic ring to be acylated and also when the ring activating groups in the aromatic ring to be acylated are absent.

Full Text	NF 47/01 IMPROVED PROCESS FOR THE LIQUID PHASE ACYLATION OF AROMATIC COMPOUNDS Field of the invention The present invention relates to an improved process for the liquid phase acylation of aromatic compounds by an acylating agent using a solid catalyst comprising metal oxide(s). The present invention particularly relates to an improved process for the acylation of aromatic compounds using a reusable solid catalyst comprising metal oxide(s). Background of the invention Friedel Crafts type acylation of aromatic compounds by various acylating agents, using homogeneous Lewis acid catalysts, such as AlClo, BFi, ZnCl2 and other metal chlorides and protonic acid catalysts such as H2SO-4, HiPO HF, etc., are well known in the art [G. A. Olah, in Friedel Crafts and related reactions: vol III, Acylation and related reactions, Wiley-Interscience Publ., New York, 1964]. US Patent 5,476,970 granted to Rains et al. Discloses a homogeneous liquid phase process for the acylation of R1R2R6H4 by R3R4H6COCl, wherein R\, R2, R3 and R4 are chemical groups using FeCl3 catalyst at high pressures. French Patents FR 2768728 (1999) and FR 2768729 (1999) of Baudry et al, disclose liquid phase homogeneous process for the benzoylation of anisole by benzoyl chloride using rare earth halides or uranyl halide. Japanese patent JP 08277241, A2 (1996) of Kunikata discloses a liquid phase process for the acylation of phenol by phenyl acetyl chloride using a homogeneous AlClo catalyst. A use of AlClo as a homogeneous catalyst is also disclosed by Oono for the acylation of toluene with acetyl chloride at high pressures in Japanese patent JP 09059205, A2 (1997). Japanese patent JP 20000086570, A2 (2000) of Shoji et al discloses a homogeneous liquid phase process for the acylation of toluene by acetyl fluoride using HF-BFi as a catalyst. The main disadvantages of the Friedel - Crafts type acylation processes based on the use of the above mentioned homogeneous acid catalysts are: 1. The separation and recovery of the dissolved acid catalysts from the liquid reaction mixture is difficult. 2. The disposal of the used acid catalysts creates environmental pollution. 3. The homogeneous acid catalysts also result in problems such as high toxicity, corrosion, spent acid disposal and also require use of more than the stoichiometric amounts. Liquid phase processes for the acylation of aromatic compounds by acyl halides using solid catalysts is also well known in the art. NF 47/01 Japanese patent JP 01089894, A2 (1995) to Myata et al discloses a liquid phase process for the acylation of toluene with benzoyl chloride using ammonium chloride treated H-beta zeolite catalyst under reflux for 3 hours to get para acylated toluene with 28% yield. French patent FR 2745287, Al (1997) of Barbier et al discloses a liquid phase acylation of anisole by benzoyl chloride under reflux using neodymium chloride deposited on montmorillonite K - 10 clay. Vincent et al (ref Tetrahedron Lett., 35, 1994, 2601) disclose that H - ZSM-5 zeolite can catalyze the acylation of phenol and anisole by benzoyl chloride at 120°C for 5 hours but not the acylation with benzoyl chloride of benzene and naphthalene. Acylation of aromatic compounds involves the electrophilic substitution of H from the aromatic nucleus of the aromatic compound. It is well known in the prior art that the electrophilic substitution is favoured by the presence of electron donating groups such as OH, alkyl, alkoxy, phenoxy, amine, alkyl amine, SH, etc., in the aromatic compound. Whereas the electophilic substitution is inhibited by the presence of electron withdrawing groups such as halo, nitro. cyano. Carboxy, aldehyde, etc., in the aromatic compound [G. A. Olah, in Friedel Crafts and related reactions Wiley-Interscience Publ., New York, 1963]. While some limitations of the homogeneous acid catalysed processes are overcome in the prior art heterogeneous solid catalysed processes described above, the acylating activity of the solid acid catalysts used in the prior art processes is low, particularly for acylating aromatic compounds not containing electron donating groups, such as benzene, naphthalene etc. Both the prior art homogeneous and heterogeneous acid catalysts are highly moisture sensitive, and hence demand moisture free or thoroughly dried reactants, solvents and catalyst for Friedel-Crafts type acylation processes. In the presence of moisture in the reaction mixture, both the above homogeneous and heterogeneous catalysts show poor activity in the Friedel-Crafts type acylation processes. Hence there is a need for finding more efficient, reusable and also moisture insensitive solid catalyst for the acylation of aromatic compounds, which overcomes the disadvantages of the prior art discussed above. Objects of the invention The main object of the present invention is to provide a liquid phase process for the acylation of aromatic compounds including those which do not contain electron donating groups, using a solid catalyst, which has high activity when, the aromatic ring activating groups (electron donating groups like alkyl, alkoxy, hydroxy, phenoxy, etc.) are present in the aromatic ring to be acylated and also when the ring activating groups in the aromatic ring to be acylated are absent, such that reaction temperature is low and/or reaction time is short. Another object of the invention is to provide a liquid phase process for acylation of aromatic compounds using a solid catalyst that is easily separable and reusable in the process. It is another object of the present invention to provide a liquid phase process for the acylation of aromatic compound that is insensitive the presence of moisture in the reaction mixture. Summary of the invention Accordingly the present invention provides an improved process for the liquid phase acylation of an aromatic compound of the formula (R1R2R3R4 - M - H by an acylating agent of the formula (R5R6R7) - Y - Z to obtain the corresponding acylated compound of the formula ((R1R2R4) - M-Y-(R 5R6R7) wherein M is an aromatic nucleus with R1R2R3, and R4 being the chemical groups as herein described attached thereto, Y is the nucleus of the acylating agent and is selected from the group consisting of C - CO, CnH2n.2CO, C6H2CnH2n-2CO and C6H2CnH2n.i(X)-CO, R5, R6 and R7 being chemical groups as herein described attached thereto Y, Z is selected from the group consisting of Cl, Br, I and OH, X is halogen, and n is an integer having a value equal to or greater than 1.0, using a solid catalyst comprising a metal oxide of the formula AOx, with or without a catalyst support as herein described wherein A is a metallic element selected from Ga, In, Tl, Fe and a mixture of two or more thereof, and x is the number of oxygen atoms required to fulfill the valance requirement of A, said process comprising, i.) pretreating the solid catalyst by contacting it with a dry gas comprising a hydrogen halide optionally in the presence of the aromatic compound to be acylated. ii.) contacting the hydrogen halide pretreated catalyst with a liquid reaction mixture comprising the aromatic compound and the acylating agent in a stirred batch reactor at following reaction conditions weight ratio of catalyst to acylating agent in the range 0.01 to 2.0, mole ratio of the aromatic compound to the acylating agent in the range of 0.1 to 100, weight ratio of non-aqueous solvent to the aromatic compound being in the range of 0 to 100, reaction temperature being in the range of 10°C to 300T, pressure in the range of 0.5 atm to 10 atm., gas hourly space velocity of inert gas bubbled through the reaction mixture being in the range of 0.1 h"1 to 5OOOh"1 and reaction period in the range of from 0.02 hours to 100 hours; iii.) cooling the reaction mixture to a temperature of 30°C, removing the catalyst from the reaction mixture by filtration and then separating the reaction products from the reaction mixture. NF 47/01 In another embodiment of the invention, R1R2R3, and R4 are each selected from hydrogen, alkane, olefininc. phenyl, alkoxy, phenoxy, hydroxyl, aldehydic, halogen, ketonic, amine, amide, thio, and sulphonic acid groups; Z is selected from Cl, Br, or OH, each of R5R6. and Ry is selected from the group consisting of hydrogen, alkane, olefinic, phenyl, halogen, nitro and cyano groups, A is selected from Ga, In and Tl or a mixture of two or more thereof, the hydrogen halide used in step ii is selected from HC1 and HBr, the weight ratio of the catalyst to the acylating agent is in the range of about 0.03 to 0.09, the mole ratio of the aromatic compound to the acylating agent is in the range of 1.0 to 20, the weight ratio of the non-aqueous solvent to the aromatic compound is in the range of 0 to 20, the reaction temperature is in the range of 20°C to 200°C. the reaction pressure is in the range of 1 atm to 5 atm, the reaction period is in the range of 0.05 hours to 20 hours, and the space velocity of inert gas is in the range of 50h"' to 5OOh'1 In another embodiment of the invention, M is selected from the group comprising a single aromatic ring containing 6 C atoms and 1 H atom, fused two aromatic rings containing 10 C atoms and 3 H atoms, and three fused aromatic rings containing 14 C atoms and 5 H atoms. In one embodiment of the invention, the used catalyst is washed with a non-aqueous solvent or aromatic substrate; and recycled directly with or without drying, to step i above. In another embodiment of the invention, R1R2R.3, and R4 are each selected from the group consisting of H, CnH2n~i, CmH2m,i, C6H5, CnH2nC6H5, OH, OCnH2n^, O C6H5, halogen, NO2, NH2, NH CnH2n.,, N(CnH2n.,)2, NHCO CnH2n,,, NHCOC6H5, CN, CHO, COOH, COOCnH2n-i, COCnH2n+i, SOiH, SO?CnH2n-i, SH, alkyl mercapto and aryl mercapto wherein n and m are integers greater than or equal to 1 and 2 respectively. In another embodiment of the invention, each of Rs, R&, and Ry is selected from the group consisting of H, CH3, C2H5, OH, OCHj, OC2H5, NO2, halogen and NH2. In another embodiment of the invention, the preferred reaction temperature is in the range of 20°C to 200°C, the preferred reaction time period is in the range of 0.1 hours to 20 hours, the preferred gas hourly space velocity of the inert gas bubbling through the reaction mixture is in the range of 50h"' to 500h"1, the weight ratio of the catalyst to the acylating agent is in the range of about 0.1 to 1, the mole ratio of the aromatic compound to the acylating •*~ "^T.~ agent is in the range of 0.5 to 20, the weight ratio of the non-aqueous solvent to the aromatic compound is in the range of 0 to 20, Z is preferably Cl or Br, M is Ga or In or a mixture thereof, the preferred hydrogen halide used in step i is HC1 or HBr, R1, R2. R3, and R4 are each selected from the group consisting of H5 alkane (CnH2n+0, olefinic (CmH2m+i), phenyl NF 47/01 (C6H5), alkoxy (OCnH2n+1), phenoxy (OC6H5), hydroxyl (OH), aldehydic (CHO), ketonic, amine (NH2), amide (CO NH2), sulfonic acid (SO3H), and thio (SH), wherein n and m are integers greater than or equal to 1 and 2 respectively, each of R5,R6, and R7 is selected from the group consisting of H, alkane(CnH2nTi), olefinic (CmH2m+i), phenyl (C6H5), haloge (Cl, Br, I or F), nitro (NO2), and cyano (CN) In another embodiment of the invention, the catalyst is supported on a meso or macroporous catalyst carrier selected from alumina, silica, silica-alumina, inert metal oxides, zeolites, and zeolite like materials. In a further embodiment of the invention, the catalyst support comprises a zeolite material selected from the group consisting of microporous zeolites (pore size In another embodiment of the invention, the solvent when used is selected from the group consisting of dichloroethane, nitrobenzene, nitromethane, chlorobenzene, n-hexane, n-heptane and n-octane. Detailed description of the invention It is observed that the catalyst used in the invention has a high activity in the acylation of aromatic compounds not only when electron donating groups, which is the aromatic ring activating group, is present in the aromatic ring to be acylated, but also when it is absent. Without being bound by the proposition, it is believed that this leads to lowering of the reaction temperature and reaction time requirements. Another advantage observed is that the solid catalyst used can be separated and reused repeatedly in the process. It is also observed that the reaction rates are high even in the presence of moisture in the reaction mixture. Pretreatment of the solid catalyst with a hydrogen halide is essential in order to activate the catalyst. The catalyst is supported on a meso or macroporous catalyst carrier selected from alumina, silica, silica-alumina, inert metal oxides, zeolites, and zeolite like materials. The zeolite material is selected from the group consisting of microporous zeolites (pore size In general, micropores have diameter below Inm, mesopores have diameter between Inm and 20nm and macropores have diameter above 20nm. The catalyst supported on a NF 47/01 microporous catalyst carrier is used generally when the both reactants have minimum molecular diameter or critical size of less than 0.7 nm. The mesoporous or macroporous catalyst carriers can be used irrespective of the size of the reactants. The reaction is carried out in a stirred batch reactor fitted with a reflex condenser and an arrangement for bubbling inert gas through the reaction mixture. Such arrangements are known in the art for liquid phase reactions. In the reaction, the main product formed is the acylated aromatic compound of the formula (R1R3R4) - M - Y - (R5R6R7) while HZ is formed as a byproduct wherein R1, R2, R3, R4, M, Y, R5, R6, and R7 and Z are as described above. The process of the invention can be carried out with or without a non-aqueous solvent selected from dichloroethane, nitrobenzene, nitromethane, chlorobenzene, n-hexane, n-heptane and n-octane. The role of the solvent is to dissolve the solid reactant or reactants and thereby facilitate the reaction there between. The solvent is not necessary when both the reactants are liquid at reaction conditions. It is observed that the solvent when used is not converted during the process. The inert gas is bubbled continuously through the reaction mixture in order to remove the byproduct form reaction mixture and thereby prevent or minimise reverse reaction. This helps to shorten the time of the reaction. The reaction takes place even in the absence of the inert gas but requires a longer time period and leads to incomplete conversion. The reflux condenser fitted with the reactor is to condense the reactants and/or the solvent and to return them to the reaction mixture and allow the inert gas that is continuously bubbling through the reaction mixture to escape along with the reaction byproduct. The reaction pressure is normally above atmospheric pressure thereby allowing the reaction to proceed at a temperature higher than the normal boiling point of the reactants and/or solvent with increase in reaction pressure. The catalyst used is heterogeneous with respect to the reaction mixture and can be removed from the reaction mixture by simple filtration and after washing with solvent or liquid aromatic compound which is to be acylated, recycled to the reaction mixture. The catalyst activates both the reactants and thereby increases the rate of the acylation reaction. During the pretreatment of the catalyst, the catalyst surface is changed by partial halidation causing modification of the active sites and/or creation of new active sites on the surface thereof. The pretreatment of the catalyst is critical to activate the catalyst. The pretreatment of the catalyst can be effected by: NF 47/01 1. contacting the solid catalyst with hydrogen halide gas in a closed vessel at room temperature for an effective period to activate the catalyst, 2. by passing a mixture of hydrogen halide and nitrogen or any other inert gas over the solid catalyst in a glass reactor at or above room temperature for a period of above O.OShours; 3. by passing a hydrogen halide gas with or without an inert gas such as nitrogen, argon, helium or the like through the reaction mixture containing the aromatic substrate, with or without the solvent, and the catalyst, in a stirred reactor at a temperature above about room temperature for a period above about 0.05 hours and then flashing the reaction mixture with an inert gas to remove physically adsorbed or absorbed hydrogen halide in the reaction mixture. The present invention is described with respect to the following examples which are illustrative and are not to be taken as limiting the scope of the invention. Definition of terms used in the examples: Conversion of reactant (%) = mole % of the reactant converted in the process. All the ratios of the aromatic compound to the acylating agent are in terms of mole ratios. All the solid catalyst to acylating agent and solvent to aromatic compound ratios are in terms of weight ratios. The flow rates of the inert gas is measured at 0°C and 1 atm pressure. Gas hourly space velocity (GHSV) is the volume of gas measured at 0°C and 1 atm pressure passed through unit volume of liquid reaction mixture per hour. Ac and Aa represent the aromatic compound to be acylated and the acylating agent respectively. Example 1: This example illustrates the process of this invention for the liquid phase acylation of benzene by benzoyl chloride to benzophenone using Ga2O3catalyst. The liquid phase acylation reaction over the solid catalyst was carried out in three steps: i The catalyst was pretreated by contacting it with hydrogen chloride gas in a closed vessel at room temperature for a period of 12 hours. ii. The pretreated catalyst was then contacted with a 15cm3 liquid reaction mixture containing aromatic compound to be acylated and an acylating agent with or without non-aqueous solvent, in a stirred batch reactor (capacity = 25,cm3) and fitted with a reflex condenser, mercury thermometer dipped in the reaction mixture, and an inlet tube for passing gas through the reaction mixture, under vigorous stirring, while bubbling moisture free inert gas through the reaction mixture at the reaction conditions given in NF 47/01 Table 1. The gaseous hydrogen halide if evolved during the reaction was measured quantitatively by absorbing it in aqueous NaOH solution by a simple acid-base titration suing phenolphthalein indicator iii. After the reaction, the reaction mixture was cooled to room temperature (30°C) and the products and the unconverted reactants present in the reaction mixture, after separating the solid catalyst from it by filtration, were analyzed by a gas chromatograph with a thermal conductivity detector, using a SE 30 column and hydrogen as a carrier gas. The solid catalyst used (Ga2O3) was prepared by calcining 25 g gallium nitrate in an air oven at 550°C for 4 hours. The results are included in Table 1. Example 2: This example illustrates the process for the liquid phase acylation of toluene by benzoyl chloride to methyl benzophenone, using Ga2O3 (20 wt%)/Si-MCM-41 catalyst. The liquid phase acylation reaction is carried out in three steps as in Example 1, at the reaction conditions given in Table 1. The solid catalyst Ga2O3 (20 wt%)/Si-MCM-41 is prepared by impregnating 27.29 g gallium nitrate dissolved in 100 ml distilled water, on 50 g fine powder of Si-MCM-41 (prepared according to Choudhary et al. Indian Academy of Sciences, Chemical Sciences) Vol. 109, p 229, 1997) by incipient wetness technique, drying the impregnated mass in an air oven at 110°C for 8 hours and calcining in air at 550°C for 4 hours. The results are included in Table 1. Examples 3 and 4: These examples illustrate the preparation of benzene and toluene by benzoyl halide to the corresponding acylated compounds using In-2O3 and Gao.67ln2.33O3 (27 wt%)/Si-MCM-41 catalysts. The liquid phase acylation over the solid catalyst was carried out in the three steps by the same procedure as in Example 1, except that in step i. the catalyst was pretreated by passing a mixture of hydrogen bromide and nitrogen (20 mol% HBr in N2) over the catalyst in a glass reactor at 50°C for a period of 0.7 hours. The reaction conditions are given in Table 1. The catalysts used in these examples are prepared as follows: IniOs was prepared by calcining 25 g indium nitrate in an air oven at 600°C for 4 hours. NF 47/01 The Gao67ln2.33C3 (27 wt%)/Si-MCM-41 was prepared by impregnating 4.09 gallium nitrate and 14.9 g indium nitrate dissolved in 50 ml distilled water on 25 g fine powder of Si-MCM-41 by incipient wetness technique, drying the impregnated mass in an air oven at 110°C for 8 hours and calcining in air at 550°C for 4.5 hours. The results are included in Table 1. Examples 5 - 16: These examples illustrate the process of the invention for the liquid phase acylation of aromatic compounds by different acylating agents to corresponding acylated aromatic compounds using different solid catalysts. The liquid phase acylation reaction over the solid catalyst was carried out in three steps by the same procedure as in Example 1, except that in step i., the catalyst was pretreated by passing a mixture of hydrogen chloride and nitrogen (12mol% HC1 in N2) through the reaction mixture containing 13 ml benzene and the catalyst in a stirred reactor at 80°C under reflux for a period of 0.5 hours, and washing the pretreated catalyst with the aromatic compound to be acylated (benzene or toluene) or the solvent to be used in the acylation reaction. The catalysts used in these examples are prepared as follows. The Ga2O3 and Ga2Oi (20 wt%)/Si-MCM-41 catalysts were prepared by the procedure in Examples 1 and 2. The Gai.oln2oC»3 catalyst was prepared by calcining a homogeneous mixture of 13.65 g gallium nitrate and 28.4 g indium nitrate in an air oven at 600°C for 4 hours. T12O (20 wt%)/SZ5564 was prepared by impregnating 5.01 g thallous nitrate dissolved in 14 ml distilled water on 20 g fine particles (>100 mesh) of SZ-5564 catalyst support (obtained from Norton Co USA, main chemical composition being 94.1% (ZrO2 + HfO2), 3.5 % CaO, 1.6% SiO2 and 0.41 % A12O3, surface area = 0.1 m2g-1; porosity = 45%) by incipient wetness technique, drying the impregnated mass in an air oven at 120°C for 8 hours and calcining in air at 550°C for 4 hours. The In2O3 (20 wt%)/Si-MCM-41 was prepared by impregnating 28.41 g indium nitrate dissolved in 100 ml distilled water on 50 g fine powders of Si-MCM-41 by incipient wetness technique, drying the impregnated mass in an air oven at 110°C for 8 hours and calcining in air at 600°C for 4 hours. The Gai.nlni.gTOs (8 wt%)/SA-5205 was prepared by impregnating a mixture of 4.09 gallium nitrate and 6.28 g indium nitrate dissolved in 35 ml distilled water on 50 g SA 5205 catalyst support (obtained from Norton Co., USA having main chemical composition: 11.8% SiO2 and 86.1 % AJ2Os; surface area NF 47/01 pore diameter ~ 200um and particle size = 100 - 150 mesh) by incipient wetness technique, drying the impregnated mass in an air oven at 100°C for 15 hours and calcining in air at 600°C for 2 hours. The In2O.3 (20 wt%)/H - beta was prepared by impregnating 28.41 g indium nitrate dissolved in 45 ml distilled water, on 25 g H - beta (prepared by the procedure described in Singh et al, Catalysis Letters, vol 32, p 327, 1995) by incipient wetness technique, drying the impregnated mass in an oven at 100°C for 15 hours and calcining in air at 600°C for 2 hours. The Gazolni oC3 (15 wt%)/H -beta was prepared by impregnating a mixture of 0.55 g gallium nitrate and 0.29 g indium nitrate dissolved in 18 ml distilled water on 10 g H-beta by incipient wetness technique drying the impregnated mass in an air oven at 100°C for 15 hours and calcining in air at 600°C for 2 hours. The Fei oGaj.oOs (15 wt%)/Si - MCM-41 was prepared by impregnating a mixture of 6.33 g ferric nitrate and 6.82 g gallium nitrate dissolved in 50 ml distilled water on 25 g fine powder of Si - MCM - 41 by incipient wetness technique, drying the impregnated mass in an air oven at 110°C for 8 hours and calcining in air at 450°C for 4 hours. Feo.eGailni 2C3 (25 wt%)/Si-MCM-41 was prepared by impregnating a mixture of 6.3 g ferric nitrate, 5.46 g gallium nitrate and 8.52 g indium nitrate dissolved in 50 ml distilled water on 25 g fine powder of Si - MCM - 41 by incipient wetness technique, drying the impregnated mass in an air oven at 110°C for 8 hours and calcining in air at 600°C for 4 hours The results are in Table 2. EXAMPLES 17-20 These comparative examples illustrate the process of this invention for the liquid phase acylation of aromatic compounds by different acylating agents to corresponding acylated aromatic compounds using solid catalysts as prepared in Examples 4 and 10, even when an appreciable level of moisture is present in the reactor. The liquid phase acylation reaction over the solid catalyst is carried out in three steps by the procedure as described in Example 1, except that in step i. the catalyst was pretreated by passing a mixture of hydrogen chloride and nitrogen (12 mol% HC1 in N:) through the reaction mixture containing 13 ml benzene and the catalyst in a stirred reactor at 80°C under reflux for a period of 0.5 hours, and washing the pretreated catalyst with the aromatic compound to be acylated (benzene or toluene). In the present .case the reaction was carnecl out using moist benzene or toluene (benzene or toluene saturated with water at 30°C). The reaction conditions and the results are given in Table 3. The results given Table 3 show that NF 47/01 the catalyst of the invention catalyses the acylation reaction even when moisture is present in the reaction mixture. EXAMPLES 21 - 24 These examples show the reusability of the catalyst used in the earlier examples for the acylation of aromatic compounds by the process of the invention. The process of the invention for the liquid phase acylation of aromatic compounds which was already used in the earlier examples was carried out using the reactor and the same procedure as described in Example 1, except that step i. was avoided and before use the used catalyst was washed with the aromatic substrate or the solvent used in the acylation reaction. The results showing the reusability of the catalyst of this invention in the process of the invention are given in Table 4. EXAMPLES 25 and 26 These comparative examples illustrate the importance of the pretreatment of In2O3 catalyst prepared in Example 3 by hydrogen chloride in step i. of the provess of the invention for the acylation of benzene by benzoyl chloride. The liquid phase acylation reaction over the catalyst was carried out by the procedure described in Example 1, except that the catalysts was not pretreated in step i. The results are included under Example 25 in Table 5. Whereas the results in Example 26 of Table 5 are for the catalyst pretreated in step i. according to the procedure described in Examples 5-16 and carrying out the reaction by the following procedures for step ii and step iii of Example 1. A comparison of conversion of the acylating agent in Examples 25 and 26 show that HC1 pretreated catalyst has a higher activity than catalyst without pretreatment. EXAMPLES 27 and 28 These comparative examples illustrate the importance of pretreatment of the GazOa (20 wt%)Si-MCM-41 catalyst prepared in Example 2 by hydrogen chloride in step i. of the process of the invention for the acylation of toluene by benzoyl chloride. The liquid phase acylation reaction over the catalyst was carried out by the procedure described in Example 2, except that the catalysts was not pretreated in step i. The results are included under Example 27 in Table 5. Whereas the results in Example 28 of Table 5 are for the catalyst pretreated in step i. according to the procedure described in Examples 5-16 and carrying out the reaction by the following procedures for step ii apd step iii of Example 2. A comparison of conversion of the acylating agent in Examples 27 and 28 show that HC1 pretreated catalyst has a higher activity than catalyst without pretreatment The observations and conclusions from. Examples 1 - 28 are given below: NF 47/01 1 The pretreatment of the catalyst in the process of the invention is critical and essential to activate the catalyst of the invention and thereby obtain high catalytic activity, i.e. high conversion of reactants in acylation reactions. 2. The catalyst of the invention shows high activity for the acylation of different aromatic compounds even when there are no electron donating groups present in the aromatic compound. 3. The catalyst of the invention shows very high activity for the acylation of aromatic compounds even in the presence of moisture iathe reaction mixture. 4. The catalyst used in the process of the invention can be reused in the process. 5. TABLE 1: Results of acylation of different aromatic compounds Example No. Example 1 Example 2 Example 3 Example 4 Catalyst Ga,O3 Ga2O, (20 wt%)/Si-MCM-41 In 2O3 Ga2O3In2O,(27 wt%)/Si-MCM-41 Reactants: Aromatic compound (Ac) Benzene Toluene Benzene Toluene Acylating agent (Aa) Benzoyl chloride Benzoyl chloride Benzoyl chloride Benzoyl bromdie Reaction Conditions: Solvent Nil Nil Nil Nil Ac/Aa mole ratio 17.0 15 17.0 17.0 Solvent/ Aa mole ratio 0.0 0.0 0.0 0.0 Catalyst/ Aa weight ratio 0.33 0.6 0.33 0.33 Temperature (°C) 80 117 80 112 Pressure (atm) 1.0 1.8 1.0 1.1 GHSVofN2(h:f) 99 99 99 55 Reaction time (hours) 3.5 1.0 2.5 2.6 Conversion of Aa (%) 37.2 85 42.6 81.2 Main product of reaction C6H,COC6H, CH3C6H4COC6H, C6H,COC6H5 CH3C6H,COC6H, Byproduct of reaction HC1 HC1 HCI HBr TABLE 2: Results of the acylation of different aromatic compounds Example No. Example 5 Example 6 Example 7 Example 8 Catalyst Ga2O3 Ga,oln2003 T12O(20 wt%)/SZ5564 Ga2O3O3(27 wt%)/Si-MCM-41 Reactants: Aromatic compound (Ac) Benzene p-Xylene Toluene Durene Acylating agent (Aa) Benzoyl chloride Benzoyl bromide Benzoyl chloride Benzoyl chloride Reaction Conditions: Solvent Nil Nil Nil Dichloroethane Ac/Aa mole ratio 17.0 15 17.0 2.5 Solvent/ Aa mple ratio 0.0 0.0 0.0 20.0 Catalyst/Aa weight ratio 0.33 0.30 0.33 0.5 Temperature (°C) 80 140 110 80 Pressure (atm) 1.0 1.0 1.0 1.0 GHSV of N2 (If;1) 99 99 99 99 Reaction time (hours) 3.6 1.0 2.0 2.5 Conversion of Aa (%) 54.7 97 90.1 97.2 Main product of reaction C6H,COC6H? (CH3),C6H3COC6H, CHaC^COCifl, (CH3)4C6H4COC6H, Byproduct of reaction HC1 HBr HC1 HBr TABLE 2 CONTINUED Example No. Example 9 Example 10 Example 1 1 Example 12 Catalyst Ga2O3(20 wt%)/Si-MCM-41 In203 (20 wt%)/Si-MCM-41 In203 (20 wt%)/Si-MCM-41 Ga, 13In, 87O3(8 wt%)/SA - 5205 Reactants: Aromatic compound (Ac) Acylating agent (Aa) 2 - methoxy naphthalene Acetyl chloride 2 - Naphthol Acetyl chloride Phenol Benzoyl chloride Phenol Acetyl chloride Reaction Conditions: Solvent Dichloroethane Dichloroethane Dichloroethane Dichloroethane Ac/Aa mole ratio 2.3 2.1 2.5 1.5 Solvent/ Aa mole ratio 21 20 23 16 Catalyst/ Aa weight ratio 0.33 0.1 0.33 0.3 Temperaiure ("C) 35 30 80 45 Pressure (atm) 1.0 1.0 1.0 13 GHSVofN2(h-') ' 85 90 110 115 Reaction time (hours) 0.6 1.5 0.25 0.8 Conversion of Aa (%) 98.7 96.2 993 98.3 Main product of reaction (CH30) C10H6COCH, (HO)C10H6COCH3 (HOjC^COCfcH, (HO)C6H4COCH3 Byproduct of reaction HC1 HC1 HC1 HC1 z: T] —4 O TABLE 2 CONTINUED: Example No. Example 13 Example 14 Example 15 Example 16 Catalyst In2O3(40 wt%)/H -beta Ga20In, 003 (3 wt%)/H-beta wt%)/Si-MCM-41 Feo6Ga12In,2O3(25 wt%)/Si-MCM-41 Reactants: Aromatic compound (Ac) Phenol Phenol Mesitylene Naphthalene Acylating agent (Aa) Acetic acid Phenyl acetyl chloride Benzoyl bromide Butyryl chloride Reaction Conditions: Solvent Nil Dichloroethane Nil Dichloroethane Ac/Aa mole ratio 0.5 2.1 7.0 0.5 Solvent/ Aa mole ratio 0.0 18.0 0.0 15 Catalyst/ Aa weight ratio 0.5 0.9 0.8 1.0 Temperature (°C) 140 85 175 80 Pressure (atm) 1.0 1.2 1.4 1.3 GHSVofN2(h") 125 93 120 0.0 Reaction time (hours) 12.5 1.1 0.25 4.7 Conversion of Aa (%) 22.3 99.1 92.0 98.5 Main product of reaction (HO)C6H4COCH3 (HO)C6H4COCH2C6H, (CH3)3C6H,COC6H5 doHvCOC^ Byproduct of reaction H2O HC1 HBr HC1 TABLE 3: Results of the acylation of different aromatic compounds Example No. Example 17 Example 18 Example 19 Example 20 Catalyst In2O3(20 wt%)/Si -MCM-41 Same as in Example 1 7 wt%)/Si-MCM-41 Same as in Example 19 Reactants: Aromatic compound (Ac) Acylating agent (Aa) Benzene Benzoyl chloride Benzene saturated with water Benzoyl chloride Toluene Benzoyl bromide Toluene saturated with water Benzoyl bromide Reaction Conditions: Solvent Nil Nil Nil Nil Ac/Aa mole ratio 15.7 15.7 170 170 Sol vent/ Aa mole ratio 0.0 0.0 0.0 0.0 Catalyst/ Aa weight ratio 0.52 0.52 0.33 0.33 Temperature (°C) 80 80 112 112 Pressure (atm) 1.0 1.0 1.1 1.1 GHSVofN2(h4) 95 95 55 55 Reaction time (hours) 2.5 2.4 2.6 2.3 Conversion of Aa (%) 52.1 52.3 93.4 95.2 Main product of reaction C6H,CO C6H, C6H,COCeH, (CH,)C(,H4COChH, (CHOC()H4COC0H, Byproduct of reaction HC1 HC1 HBr HBr TABLE 4: Results showing the reusability of the catalyst of the invention for the process of the invention Example No. Example 2 1 Example 22 Example 23 Example 24 Catalyst The catalyst after its The catalyst after its use in The catalyst after its The catalyst after its use in in use in Example 19 Example 21 use in Example 16 Example 19 Reactants: Aromatic compound (Ac) p-xylene Anisole Benzene Naphthalene Acylating agent (Aa) Benzoyl chloride Butyryl chloride Benzoyl chloride Propionyl chloride Reaction Conditions: Solvent Nil Nil Nil Nitromethane Ac/Aa mole ratio 17.9 16.5 17.1 2.0 Solvent/ Aa mole ratio 0.0 0.0 0.0 15.0 Catalyst/ Aa weight ratio 0.3 0.25 0.8 0.5 Temperature (°C) 140 163 87 103 Pressure (atm) 1.0 1.3 1.5 1.2 GHSVofN2(h') 105 95 97 91 Reaction time (hours) 1.0 1.5 9.0 2.8 Conversion of Aa (%) 97.9 97.5 98.4 98.6 Main product of reaction (CH3)2C6H3COC6H, (CH,0)C6H4COC4H9 C6H,COC6H, CIOH7COC,H7 Byproduct of reaction HC1 HC1 HC1 HC1 £>. -4 TABLE 5: Results of acylation of different aromatic compounds with and without pretreatment of catalyst. Example No. Example 25 Example 26 Example 27 Example 28 Catalyst In2O, ln2O3 Ga,O3 (20 wt%)/Si -MCM-41 Ga2O3 (20 wt%)/Si -MCM-41 Reactants: Aromatic compound (Ac) Benzene Benzene Toluene Toluene Acylating agent (Aa) Benzoyl chloride Benzoyl chloride Benzoyl chloride Benzoyl chloride Reaction Conditions: Solvent Nil Nil Nil Nil Ac/Aa mole ratio 17.0 170 15 15 Solvent/ Aa mole ratio 0.0 0.0 0.0 0.0 Catalyst/ Aa weight ratio 0.33 0.33 0.6 0.6 Temperature (°C) 80 80 117 117 Pressure (atm) 1.0 1.0 1.8 1.8 GHSVofN2(h") 99 99 99 99 Reaction time (hours) 2.6 2.8 1.0 1.0 Conversion of Aa (%) 31.3 52.5 77 95.1 Main product of reaction C6H,COC6H, C(,H,COC6H? CH,C6H4COC6H5 CH,C6H,COC6H, Byproduct of reaction HC1 HC1 HCI HCI NF 47/01 Advantages of the invention: The process of the invention has the following advantages over the prior art homogeneous acid catalysed processes for the acylation of aromatic compounds. 1 The catalyst used is a heterogeneous solid catalyst and hence can be separated from the reaction products simply by filtration. 2. The separated catalysts can be reused a number of times in the process of the invention. 3. The catalyst is non-corrosive. The process of the invention can be differentiated from prior art processes bsed on the use of solid acid catalyst for the acylation of aromatic reactions. 1. The activity of the catalyst used in the invention is high thereby increasing the speed of reaction and reducing the time required for completion of the reaction. 2. The catalyst of the invention can be reused a number of times in the process of the invention and shows high activity in the process even after repeated use. 3. The process of the invention can be used for the acylation of both small and large size aromatic compounds with both small and large sized acylating agents to obtain the corresponding acylated aromatic compounds. 4. When the inert gas is bubbled through the reaction mixture continuously, the byproduct formed is removed continuously thereby preventing or minimising the reverse acylation reaction This results in speeding up of the time required for the reaction. 5. By using pressures of greater than or equal to 1 atm., the reaction can be carried out at temperatures higher than the normal boiling point of either the reactants or the solvent, thereby shortening the reaction period. The inhibition of the reaction is avoided or minimised due to strong adsorption of the reactants, products or solvent on the catalyst. 6 The process of the invention is effective even for the acieration of benzene which does not contain any aromatic ring activating electron donating group such as alkyl, alkoxy, hydroxy, etc. The rate of reaction is rapid at mild reaction conditions and hence the time for reaction is short. 7. The process of the invention results in rapid acylation of aromatic compounds even when the reaction mixture contains moisture. The catalyst is not deactivated due to the presence of moisture in the reaction mixture. Thus, unlike prior art homogeneous and solid acid catalysts, the catalyst of the invention does not require moisture, free conditions tdTje active. This results in saving of costs towards removal of moisture from the reaction system or the reactants. NF 47/01 8. The catalyst of the invention is acidic and basic in nature, the process of the invention can be used for acylating both acid sensitive aromatic compounds and basic aromatic compounds. We Claim: 1. An improved process for the liquid phase acylation of an aromatic compound of the formula (RiR2R3R4) - M - H by an acylating agent of the formula (R5R6R7) -Y - Z to obtain the corresponding acylated compound of the formula (RiR2R3R4) - M-Y-(R5R6R7) wherein M is an aromatic nucleus with R1R2R3, and R4 being the chemical groups as herein described attached thereto, Y is the nucleus of the acylating agent and is selected from the group consisting of C - CO, CnH2n-2CO, C6H2CnH2n-2CO and C6H2CnH2n-i(X)-CO, R5, R6 and R7 being chemical groups as herein described attached thereto Y, Z is selected from the group consisting of Cl, Br, I and OH, X is halogen, and n is an integer having a value equal to or greater than 1.0, using a solid catalyst comprising a metal oxide of the formula AOx, with or without a catalyst support as herein described wherein A is a metallic element selected from Ga, In, Tl, Fe and a mixture of two or more thereof, and x is the number of oxygen atoms required to fulfill the valance requirement of A, said process comprising, i. pretreating the solid catalyst by contacting it with a dry gas comprising a hydrogen halide optionally in the presence of the aromatic compound to be acylated. ii. contacting the hydrogen halide pretreated catalyst with a liquid reaction mixture comprising the aromatic compound and the acylating agent in a stirred batch reactor at following reaction conditions weight ratio of catalyst to acylating agent in the range 0.01 to 2.0, mole ratio of the aromatic compound to the acylating agent in the range of 0.1 to 100, weight ratio of non-aqueous solvent to the aromatic compound being in the range of 0 to 100, reaction temperature being in the range of 10°C to 300°C, pressure in the range of 0.5 atm to 10 atm., gas hourly space velocity of inert gas bubbled through the reaction mixture being in the range of 0.1 h"1 to 5OOOh"1 and reaction period in the range of from 0.02 hours to 100 hours; iii. cooling the reaction mixture to a temperature of 30°C, removing the catalyst from the reaction mixture by filtration and then separating the reaction products from the reaction mixture. 2. A process as claimed in claim 1 wherein R1, R2, R3 and R4 are each selected from hydrogen, alkane, olefinic, phenyl, alkoxy, phenoxy, hydroxyl, aldehydic, halogen, ketonic, amine, amide, thio, and sulphonic acid groups. 3. A process as claimed in claims 1 and 2 wherein Z comprises Cl, Br, or OH. 4. A process as claimed in any preceding claims wherein each of Rs, R6, and R7is selected from the group consisting of hydrogen, alkane, olefinic, phenyl, halogen, nitro and cyano groups. 5. A process as claimed in any preceding claims wherein A is selected from the group consisting of Ga, In and TI and a mixture of any two or more thereof. 6. A process as claimed in any preceding claims wherein the hydrogen halide used in step ii is selected from HC1 gas and HBr gas. 7. A process as claimed in nay preceding claims wherein the weight ratio of the catalyst to the acylating agent is in the range of 0.03 to 0.09. 8. A process as claimed in any proceeding claims wherein the mole ratio of the aromatic compound to the acylating agent is in the range of 1.0 to 20. 9. A process as claimed in any preceding claim wherein the weight ratio of the non- aqueous solvent to the aromatic compound is in the range of 0 to 20. 10. A process as claimed in any proceeding claims wherein the reaction temperature is preferably in the range of 20°C to 200°C. 11. A process as claimed in any preceding claim wherein the reaction pressure is preferably in the range of 1 atm to 5 atm. 12. A process as claimed in any preceding claim wherein the reaction period is preferably in the range of 0.05 hours to 20 hours. 13. A process as claimed in any preceding claim wherein the space velocity of inert gas is preferably in three range of 50h"1 to 5OOh'1. 14. A process as claimed in any preceding claim wherein M is selected from the group comprising a single aromatic ring containing 6 C atoms and 1 H atom, fused two aromatic rings containing 10 C atoms and 3 H atoms, and three fused aromatic rings containing 14 C atoms and 5 H atoms. 15. A process as claimed in nay preceding claim wherein the used catalyst is washed with a non-aqueous solvent or the aromatic compound and recycled directly with or without drying to step ii. 16. A process as claimed in claim 1 wherein R1, R2, R3 and R4 are each selected from the group consisting of H, CnH2n-i, CmH2m+1C6H5, CnH2nC6H55 OH, OCnH2n-i, O C6H5, halogen, NO2, NH2, NH CnH2n+1> N(CnH2n.+1)2, NHCO CnH2n+,, NHCOC6H5, CN, CHO, COOH, COOCnH2n.i, SO3H, SO3CnH2n+iSH, alkyl mercapto and aryl mercapto wherein n and m are integers greater than or equal to 1 and 2 respectively. 17. A process as claimed in claim 1 wherein each of R5, Re, and R7 is selected from the group consisting of H, CH3, C2H5, OH, OCH3, OC2H5, NO2, halogen and NH2. 18. A process as claimed in any preceding claims wherein the reaction time period is preferably in the range of 0.1 hours to 20 hours. 19. A process as claimed in any proceeding claims wherein the weight ratio of the catalyst to the acylating agent is in the range of 0.1 to 1. 20. A process as claimed in any proceeding claims wherein the mole ratio of the aromatic compound to the acylating agent is in the range of 0.5 to 20. 21. A process as claimed in any proceeding claims wherein Z is Cl or Br. 22. A process as claimed in any preceding claims wherein M is Ga or In or a mixture thereof. 23. A process as claimed in any preceding claim wherein the catalyst is supported on a meso or macroporous catalyst carrier selected from alumina, silica, silica- alumina, inert metal oxides, zeolites, and zeolite like materials. 24. A process as claimed in claim 23 wherein the catalyst support comprises a microporous zeolite material having pore size less than or equal tol.Onm selected from the group consisting of zeolite X, zeolite Y, mordenite, Zeolite L, zeolite beta, ZSM 5, ZSM 8 and ZSM 11. 25. A process as claimed in claim 23 wherein the catalyst support comprises a mesoporous zeolite material having pore size in the range of 1.5 mnm to 50 nm selected from the group consisting of M41S type material and MCM41. 26. A process as claimed in any preceding claim wherein the solvent when used is selected from the group consisting of dichloroethane, nitrobenzene, nitromethane, chlorobenzene, n-hexane, n-heptane and n-octane 27. An improved process for the liquid phase acylation of aromatic compounds substantially as described hereinbefore and with reference to the foregoing examples.

Full Text

NF 47/01
IMPROVED PROCESS FOR THE LIQUID PHASE ACYLATION OF AROMATIC
COMPOUNDS Field of the invention
The present invention relates to an improved process for the liquid phase acylation of aromatic compounds by an acylating agent using a solid catalyst comprising metal oxide(s). The present invention particularly relates to an improved process for the acylation of aromatic compounds using a reusable solid catalyst comprising metal oxide(s). Background of the invention
Friedel Crafts type acylation of aromatic compounds by various acylating agents, using homogeneous Lewis acid catalysts, such as AlClo, BFi, ZnCl2 and other metal chlorides and protonic acid catalysts such as H2SO-4, HiPO HF, etc., are well known in the art [G. A. Olah, in Friedel Crafts and related reactions: vol III, Acylation and related reactions, Wiley-Interscience Publ., New York, 1964].
US Patent 5,476,970 granted to Rains et al. Discloses a homogeneous liquid phase process for the acylation of R1R2R6H4 by R3R4H6COCl, wherein R\, R2, R3 and R4 are chemical groups using FeCl3 catalyst at high pressures. French Patents FR 2768728 (1999) and FR 2768729 (1999) of Baudry et al, disclose liquid phase homogeneous process for the benzoylation of anisole by benzoyl chloride using rare earth halides or uranyl halide.
Japanese patent JP 08277241, A2 (1996) of Kunikata discloses a liquid phase process for the acylation of phenol by phenyl acetyl chloride using a homogeneous AlClo catalyst. A use of AlClo as a homogeneous catalyst is also disclosed by Oono for the acylation of toluene with acetyl chloride at high pressures in Japanese patent JP 09059205, A2 (1997). Japanese patent JP 20000086570, A2 (2000) of Shoji et al discloses a homogeneous liquid phase process for the acylation of toluene by acetyl fluoride using HF-BFi as a catalyst.
The main disadvantages of the Friedel - Crafts type acylation processes based on the use of the above mentioned homogeneous acid catalysts are:
1. The separation and recovery of the dissolved acid catalysts from the liquid reaction
mixture is difficult.
2. The disposal of the used acid catalysts creates environmental pollution.
3. The homogeneous acid catalysts also result in problems such as high toxicity, corrosion,
spent acid disposal and also require use of more than the stoichiometric amounts.
Liquid phase processes for the acylation of aromatic compounds by acyl halides using solid catalysts is also well known in the art.

NF 47/01
Japanese patent JP 01089894, A2 (1995) to Myata et al discloses a liquid phase
process for the acylation of toluene with benzoyl chloride using ammonium chloride treated H-beta zeolite catalyst under reflux for 3 hours to get para acylated toluene with 28% yield. French patent FR 2745287, Al (1997) of Barbier et al discloses a liquid phase acylation of anisole by benzoyl chloride under reflux using neodymium chloride deposited on montmorillonite K - 10 clay.
Vincent et al (ref Tetrahedron Lett., 35, 1994, 2601) disclose that H - ZSM-5 zeolite can catalyze the acylation of phenol and anisole by benzoyl chloride at 120°C for 5 hours but not the acylation with benzoyl chloride of benzene and naphthalene.
Acylation of aromatic compounds involves the electrophilic substitution of H from the aromatic nucleus of the aromatic compound. It is well known in the prior art that the electrophilic substitution is favoured by the presence of electron donating groups such as OH, alkyl, alkoxy, phenoxy, amine, alkyl amine, SH, etc., in the aromatic compound. Whereas the electophilic substitution is inhibited by the presence of electron withdrawing groups such as halo, nitro. cyano. Carboxy, aldehyde, etc., in the aromatic compound [G. A. Olah, in Friedel Crafts and related reactions Wiley-Interscience Publ., New York, 1963].
While some limitations of the homogeneous acid catalysed processes are overcome in the prior art heterogeneous solid catalysed processes described above, the acylating activity of the solid acid catalysts used in the prior art processes is low, particularly for acylating aromatic compounds not containing electron donating groups, such as benzene, naphthalene etc. Both the prior art homogeneous and heterogeneous acid catalysts are highly moisture sensitive, and hence demand moisture free or thoroughly dried reactants, solvents and catalyst for Friedel-Crafts type acylation processes. In the presence of moisture in the reaction mixture, both the above homogeneous and heterogeneous catalysts show poor activity in the Friedel-Crafts type acylation processes. Hence there is a need for finding more efficient, reusable and also moisture insensitive solid catalyst for the acylation of aromatic compounds, which overcomes the disadvantages of the prior art discussed above. Objects of the invention
The main object of the present invention is to provide a liquid phase process for the acylation of aromatic compounds including those which do not contain electron donating groups, using a solid catalyst, which has high activity when, the aromatic ring activating groups (electron donating groups like alkyl, alkoxy, hydroxy, phenoxy, etc.) are present in the aromatic ring to be acylated and also when the ring activating groups in the aromatic ring to be acylated are absent, such that reaction temperature is low and/or reaction time is short.

Another object of the invention is to provide a liquid phase process for acylation of
aromatic compounds using a solid catalyst that is easily separable and reusable in the
process.
It is another object of the present invention to provide a liquid phase process for the
acylation of aromatic compound that is insensitive the presence of moisture in the
reaction mixture.
Summary of the invention
Accordingly the present invention provides an improved process for the liquid phase acylation of an aromatic compound of the formula (R1R2R3R4 - M - H by an acylating agent of the formula (R5R6R7) - Y - Z to obtain the corresponding acylated compound of the formula ((R1R2R4) - M-Y-(R 5R6R7) wherein M is an aromatic nucleus with R1R2R3, and R4 being the chemical groups as herein described attached thereto, Y is the nucleus of the acylating agent and is selected from the group consisting of C - CO, CnH2n.2CO, C6H2CnH2n-2CO and C6H2CnH2n.i(X)-CO, R5, R6 and R7 being chemical groups as herein described attached thereto Y, Z is selected from the group consisting of Cl, Br, I and OH, X is halogen, and n is an integer having a value equal to or greater than 1.0, using a solid catalyst comprising a metal oxide of the formula AOx, with or without a catalyst support as herein described wherein A is a metallic element selected from Ga, In, Tl, Fe and a mixture of two or more thereof, and x is the number of oxygen atoms required to fulfill the valance requirement of A, said process comprising,
i.) pretreating the solid catalyst by contacting it with a dry gas comprising a hydrogen halide optionally in the presence of the aromatic compound to be acylated.
ii.) contacting the hydrogen halide pretreated catalyst with a liquid reaction mixture comprising the aromatic compound and the acylating agent in a stirred batch reactor at following reaction conditions weight ratio of catalyst to acylating agent in the range 0.01 to 2.0, mole ratio of the aromatic compound to the acylating agent in the range of 0.1 to 100, weight ratio of non-aqueous solvent to the aromatic compound being in the range of 0 to 100, reaction temperature being in the range of 10°C to 300T, pressure in the range of 0.5 atm to 10 atm., gas hourly space velocity of inert gas bubbled through the reaction mixture being in the range of 0.1 h"1 to 5OOOh"1 and reaction period in the range of from 0.02 hours to 100 hours;
iii.) cooling the reaction mixture to a temperature of 30°C, removing the catalyst from the reaction mixture by filtration and then separating the reaction products from the reaction mixture.
NF 47/01
In another embodiment of the invention, R1R2R3, and R4 are each selected from
hydrogen, alkane, olefininc. phenyl, alkoxy, phenoxy, hydroxyl, aldehydic, halogen, ketonic, amine, amide, thio, and sulphonic acid groups; Z is selected from Cl, Br, or OH, each of R5R6. and Ry is selected from the group consisting of hydrogen, alkane, olefinic, phenyl, halogen, nitro and cyano groups, A is selected from Ga, In and Tl or a mixture of two or more thereof, the hydrogen halide used in step ii is selected from HC1 and HBr, the weight ratio of the catalyst to the acylating agent is in the range of about 0.03 to 0.09, the mole ratio of the aromatic compound to the acylating agent is in the range of 1.0 to 20, the weight ratio of the non-aqueous solvent to the aromatic compound is in the range of 0 to 20, the reaction temperature is in the range of 20°C to 200°C. the reaction pressure is in the range of 1 atm to 5 atm, the reaction period is in the range of 0.05 hours to 20 hours, and the space velocity of inert gas is in the range of 50h"' to 5OOh'1
In another embodiment of the invention, M is selected from the group comprising a single aromatic ring containing 6 C atoms and 1 H atom, fused two aromatic rings containing 10 C atoms and 3 H atoms, and three fused aromatic rings containing 14 C atoms and 5 H atoms.
In one embodiment of the invention, the used catalyst is washed with a non-aqueous solvent or aromatic substrate; and recycled directly with or without drying, to step i above.
In another embodiment of the invention, R1R2R.3, and R4 are each selected from the group consisting of H, CnH2n~i, CmH2m,i, C6H5, CnH2nC6H5, OH, OCnH2n^, O C6H5, halogen, NO2, NH2, NH CnH2n.,, N(CnH2n.,)2, NHCO CnH2n,,, NHCOC6H5, CN, CHO, COOH, COOCnH2n-i, COCnH2n+i, SOiH, SO?CnH2n-i, SH, alkyl mercapto and aryl mercapto wherein n and m are integers greater than or equal to 1 and 2 respectively.
In another embodiment of the invention, each of Rs, R&, and Ry is selected from the group consisting of H, CH3, C2H5, OH, OCHj, OC2H5, NO2, halogen and NH2.
In another embodiment of the invention, the preferred reaction temperature is in the range of 20°C to 200°C, the preferred reaction time period is in the range of 0.1 hours to 20 hours, the preferred gas hourly space velocity of the inert gas bubbling through the reaction mixture is in the range of 50h"' to 500h"1, the weight ratio of the catalyst to the acylating agent is in the range of about 0.1 to 1, the mole ratio of the aromatic compound to the acylating
•*~ "^T.~
agent is in the range of 0.5 to 20, the weight ratio of the non-aqueous solvent to the aromatic compound is in the range of 0 to 20, Z is preferably Cl or Br, M is Ga or In or a mixture thereof, the preferred hydrogen halide used in step i is HC1 or HBr, R1, R2. R3, and R4 are each selected from the group consisting of H5 alkane (CnH2n+0, olefinic (CmH2m+i), phenyl
NF 47/01
(C6H5), alkoxy (OCnH2n+1), phenoxy (OC6H5), hydroxyl (OH), aldehydic (CHO), ketonic,
amine (NH2), amide (CO NH2), sulfonic acid (SO3H), and thio (SH), wherein n and m are integers greater than or equal to 1 and 2 respectively, each of R5,R6, and R7 is selected from the group consisting of H, alkane(CnH2nTi), olefinic (CmH2m+i), phenyl (C6H5), haloge (Cl, Br, I or F), nitro (NO2), and cyano (CN)
In another embodiment of the invention, the catalyst is supported on a meso or macroporous catalyst carrier selected from alumina, silica, silica-alumina, inert metal oxides, zeolites, and zeolite like materials.
In a further embodiment of the invention, the catalyst support comprises a zeolite material selected from the group consisting of microporous zeolites (pore size In another embodiment of the invention, the solvent when used is selected from the group consisting of dichloroethane, nitrobenzene, nitromethane, chlorobenzene, n-hexane, n-heptane and n-octane. Detailed description of the invention
It is observed that the catalyst used in the invention has a high activity in the acylation of aromatic compounds not only when electron donating groups, which is the aromatic ring activating group, is present in the aromatic ring to be acylated, but also when it is absent. Without being bound by the proposition, it is believed that this leads to lowering of the reaction temperature and reaction time requirements.
Another advantage observed is that the solid catalyst used can be separated and reused repeatedly in the process. It is also observed that the reaction rates are high even in the presence of moisture in the reaction mixture. Pretreatment of the solid catalyst with a hydrogen halide is essential in order to activate the catalyst.
The catalyst is supported on a meso or macroporous catalyst carrier selected from alumina, silica, silica-alumina, inert metal oxides, zeolites, and zeolite like materials. The zeolite material is selected from the group consisting of microporous zeolites (pore size In general, micropores have diameter below Inm, mesopores have diameter between Inm and 20nm and macropores have diameter above 20nm. The catalyst supported on a
NF 47/01
microporous catalyst carrier is used generally when the both reactants have minimum
molecular diameter or critical size of less than 0.7 nm. The mesoporous or macroporous catalyst carriers can be used irrespective of the size of the reactants. The reaction is carried out in a stirred batch reactor fitted with a reflex condenser and an arrangement for bubbling inert gas through the reaction mixture. Such arrangements are known in the art for liquid phase reactions.
In the reaction, the main product formed is the acylated aromatic compound of the formula (R1R3R4) - M - Y - (R5R6R7) while HZ is formed as a byproduct wherein R1, R2, R3, R4, M, Y, R5, R6, and R7 and Z are as described above.
The process of the invention can be carried out with or without a non-aqueous solvent selected from dichloroethane, nitrobenzene, nitromethane, chlorobenzene, n-hexane, n-heptane and n-octane. The role of the solvent is to dissolve the solid reactant or reactants and thereby facilitate the reaction there between. The solvent is not necessary when both the reactants are liquid at reaction conditions. It is observed that the solvent when used is not converted during the process.
The inert gas is bubbled continuously through the reaction mixture in order to remove the byproduct form reaction mixture and thereby prevent or minimise reverse reaction. This helps to shorten the time of the reaction. The reaction takes place even in the absence of the inert gas but requires a longer time period and leads to incomplete conversion.
The reflux condenser fitted with the reactor is to condense the reactants and/or the solvent and to return them to the reaction mixture and allow the inert gas that is continuously bubbling through the reaction mixture to escape along with the reaction byproduct. The reaction pressure is normally above atmospheric pressure thereby allowing the reaction to proceed at a temperature higher than the normal boiling point of the reactants and/or solvent with increase in reaction pressure.
The catalyst used is heterogeneous with respect to the reaction mixture and can be removed from the reaction mixture by simple filtration and after washing with solvent or liquid aromatic compound which is to be acylated, recycled to the reaction mixture. The catalyst activates both the reactants and thereby increases the rate of the acylation reaction. During the pretreatment of the catalyst, the catalyst surface is changed by partial halidation causing modification of the active sites and/or creation of new active sites on the surface thereof. The pretreatment of the catalyst is critical to activate the catalyst. The pretreatment of the catalyst can be effected by:

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1. contacting the solid catalyst with hydrogen halide gas in a closed vessel at room
temperature for an effective period to activate the catalyst,
2. by passing a mixture of hydrogen halide and nitrogen or any other inert gas over the solid
catalyst in a glass reactor at or above room temperature for a period of above O.OShours;
3. by passing a hydrogen halide gas with or without an inert gas such as nitrogen, argon,
helium or the like through the reaction mixture containing the aromatic substrate, with or
without the solvent, and the catalyst, in a stirred reactor at a temperature above about
room temperature for a period above about 0.05 hours and then flashing the reaction
mixture with an inert gas to remove physically adsorbed or absorbed hydrogen halide in
the reaction mixture.
The present invention is described with respect to the following examples which are illustrative and are not to be taken as limiting the scope of the invention. Definition of terms used in the examples:
Conversion of reactant (%) = mole % of the reactant converted in the process. All the ratios of the aromatic compound to the acylating agent are in terms of mole ratios. All the solid catalyst to acylating agent and solvent to aromatic compound ratios are in terms of weight ratios.
The flow rates of the inert gas is measured at 0°C and 1 atm pressure. Gas hourly space velocity (GHSV) is the volume of gas measured at 0°C and 1 atm pressure passed through unit volume of liquid reaction mixture per hour.
Ac and Aa represent the aromatic compound to be acylated and the acylating agent respectively. Example 1:
This example illustrates the process of this invention for the liquid phase acylation of benzene by benzoyl chloride to benzophenone using Ga2O3catalyst. The liquid phase acylation reaction over the solid catalyst was carried out in three steps: i The catalyst was pretreated by contacting it with hydrogen chloride gas in a closed vessel
at room temperature for a period of 12 hours.
ii. The pretreated catalyst was then contacted with a 15cm3 liquid reaction mixture containing aromatic compound to be acylated and an acylating agent with or without non-aqueous solvent, in a stirred batch reactor (capacity = 25,cm3) and fitted with a reflex condenser, mercury thermometer dipped in the reaction mixture, and an inlet tube for passing gas through the reaction mixture, under vigorous stirring, while bubbling moisture free inert gas through the reaction mixture at the reaction conditions given in
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Table 1. The gaseous hydrogen halide if evolved during the reaction was measured
quantitatively by absorbing it in aqueous NaOH solution by a simple acid-base titration suing phenolphthalein indicator
iii. After the reaction, the reaction mixture was cooled to room temperature (30°C) and the products and the unconverted reactants present in the reaction mixture, after separating the solid catalyst from it by filtration, were analyzed by a gas chromatograph with a thermal conductivity detector, using a SE 30 column and hydrogen as a carrier gas.
The solid catalyst used (Ga2O3) was prepared by calcining 25 g gallium nitrate in an air oven at 550°C for 4 hours. The results are included in Table 1. Example 2:
This example illustrates the process for the liquid phase acylation of toluene by benzoyl chloride to methyl benzophenone, using Ga2O3 (20 wt%)/Si-MCM-41 catalyst. The liquid phase acylation reaction is carried out in three steps as in Example 1, at the reaction conditions given in Table 1.
The solid catalyst Ga2O3 (20 wt%)/Si-MCM-41 is prepared by impregnating 27.29 g gallium nitrate dissolved in 100 ml distilled water, on 50 g fine powder of Si-MCM-41 (prepared according to Choudhary et al. Indian Academy of Sciences, Chemical Sciences) Vol. 109, p 229, 1997) by incipient wetness technique, drying the impregnated mass in an air oven at 110°C for 8 hours and calcining in air at 550°C for 4 hours.
The results are included in Table 1. Examples 3 and 4:
These examples illustrate the preparation of benzene and toluene by benzoyl halide to the corresponding acylated compounds using In-2O3 and Gao.67ln2.33O3 (27 wt%)/Si-MCM-41 catalysts.
The liquid phase acylation over the solid catalyst was carried out in the three steps by the same procedure as in Example 1, except that in step i. the catalyst was pretreated by passing a mixture of hydrogen bromide and nitrogen (20 mol% HBr in N2) over the catalyst in a glass reactor at 50°C for a period of 0.7 hours. The reaction conditions are given in Table 1.
The catalysts used in these examples are prepared as follows:
IniOs was prepared by calcining 25 g indium nitrate in an air oven at 600°C for 4 hours.

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The Gao67ln2.33C3 (27 wt%)/Si-MCM-41 was prepared by impregnating 4.09 gallium nitrate
and 14.9 g indium nitrate dissolved in 50 ml distilled water on 25 g fine powder of Si-MCM-41 by incipient wetness technique, drying the impregnated mass in an air oven at 110°C for 8 hours and calcining in air at 550°C for 4.5 hours. The results are included in Table 1. Examples 5 - 16:
These examples illustrate the process of the invention for the liquid phase acylation of aromatic compounds by different acylating agents to corresponding acylated aromatic compounds using different solid catalysts.
The liquid phase acylation reaction over the solid catalyst was carried out in three steps by the same procedure as in Example 1, except that in step i., the catalyst was pretreated by passing a mixture of hydrogen chloride and nitrogen (12mol% HC1 in N2) through the reaction mixture containing 13 ml benzene and the catalyst in a stirred reactor at 80°C under reflux for a period of 0.5 hours, and washing the pretreated catalyst with the aromatic compound to be acylated (benzene or toluene) or the solvent to be used in the acylation reaction. The catalysts used in these examples are prepared as follows.
The Ga2O3 and Ga2Oi (20 wt%)/Si-MCM-41 catalysts were prepared by the procedure in Examples 1 and 2.
The Gai.oln2oC»3 catalyst was prepared by calcining a homogeneous mixture of 13.65 g gallium nitrate and 28.4 g indium nitrate in an air oven at 600°C for 4 hours.
T12O (20 wt%)/SZ5564 was prepared by impregnating 5.01 g thallous nitrate dissolved in 14 ml distilled water on 20 g fine particles (>100 mesh) of SZ-5564 catalyst support (obtained from Norton Co USA, main chemical composition being 94.1% (ZrO2 + HfO2), 3.5 % CaO, 1.6% SiO2 and 0.41 % A12O3, surface area = 0.1 m2g-1; porosity = 45%) by incipient wetness technique, drying the impregnated mass in an air oven at 120°C for 8 hours and calcining in air at 550°C for 4 hours.
The In2O3 (20 wt%)/Si-MCM-41 was prepared by impregnating 28.41 g indium nitrate dissolved in 100 ml distilled water on 50 g fine powders of Si-MCM-41 by incipient wetness technique, drying the impregnated mass in an air oven at 110°C for 8 hours and calcining in air at 600°C for 4 hours.
The Gai.nlni.gTOs (8 wt%)/SA-5205 was prepared by impregnating a mixture of 4.09 gallium nitrate and 6.28 g indium nitrate dissolved in 35 ml distilled water on 50 g SA 5205 catalyst support (obtained from Norton Co., USA having main chemical composition: 11.8% SiO2 and 86.1 % AJ2Os; surface area
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pore diameter ~ 200um and particle size = 100 - 150 mesh) by incipient wetness technique,
drying the impregnated mass in an air oven at 100°C for 15 hours and calcining in air at 600°C for 2 hours.
The In2O.3 (20 wt%)/H - beta was prepared by impregnating 28.41 g indium nitrate dissolved in 45 ml distilled water, on 25 g H - beta (prepared by the procedure described in Singh et al, Catalysis Letters, vol 32, p 327, 1995) by incipient wetness technique, drying the impregnated mass in an oven at 100°C for 15 hours and calcining in air at 600°C for 2 hours.
The Gazolni oC3 (15 wt%)/H -beta was prepared by impregnating a mixture of 0.55 g gallium nitrate and 0.29 g indium nitrate dissolved in 18 ml distilled water on 10 g H-beta by incipient wetness technique drying the impregnated mass in an air oven at 100°C for 15 hours and calcining in air at 600°C for 2 hours.
The Fei oGaj.oOs (15 wt%)/Si - MCM-41 was prepared by impregnating a mixture of 6.33 g ferric nitrate and 6.82 g gallium nitrate dissolved in 50 ml distilled water on 25 g fine powder of Si - MCM - 41 by incipient wetness technique, drying the impregnated mass in an air oven at 110°C for 8 hours and calcining in air at 450°C for 4 hours.
Feo.eGailni 2C3 (25 wt%)/Si-MCM-41 was prepared by impregnating a mixture of 6.3 g ferric nitrate, 5.46 g gallium nitrate and 8.52 g indium nitrate dissolved in 50 ml distilled water on 25 g fine powder of Si - MCM - 41 by incipient wetness technique, drying the impregnated mass in an air oven at 110°C for 8 hours and calcining in air at 600°C for 4 hours The results are in Table 2. EXAMPLES 17-20
These comparative examples illustrate the process of this invention for the liquid phase acylation of aromatic compounds by different acylating agents to corresponding acylated aromatic compounds using solid catalysts as prepared in Examples 4 and 10, even when an appreciable level of moisture is present in the reactor.
The liquid phase acylation reaction over the solid catalyst is carried out in three steps by the procedure as described in Example 1, except that in step i. the catalyst was pretreated by passing a mixture of hydrogen chloride and nitrogen (12 mol% HC1 in N:) through the reaction mixture containing 13 ml benzene and the catalyst in a stirred reactor at 80°C under reflux for a period of 0.5 hours, and washing the pretreated catalyst with the aromatic compound to be acylated (benzene or toluene). In the present .case the reaction was carnecl out using moist benzene or toluene (benzene or toluene saturated with water at 30°C). The reaction conditions and the results are given in Table 3. The results given Table 3 show that
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the catalyst of the invention catalyses the acylation reaction even when moisture is present in
the reaction mixture. EXAMPLES 21 - 24
These examples show the reusability of the catalyst used in the earlier examples for the acylation of aromatic compounds by the process of the invention.
The process of the invention for the liquid phase acylation of aromatic compounds which was already used in the earlier examples was carried out using the reactor and the same procedure as described in Example 1, except that step i. was avoided and before use the used catalyst was washed with the aromatic substrate or the solvent used in the acylation reaction.
The results showing the reusability of the catalyst of this invention in the process of the invention are given in Table 4. EXAMPLES 25 and 26
These comparative examples illustrate the importance of the pretreatment of In2O3 catalyst prepared in Example 3 by hydrogen chloride in step i. of the provess of the invention for the acylation of benzene by benzoyl chloride.
The liquid phase acylation reaction over the catalyst was carried out by the procedure described in Example 1, except that the catalysts was not pretreated in step i. The results are included under Example 25 in Table 5. Whereas the results in Example 26 of Table 5 are for the catalyst pretreated in step i. according to the procedure described in Examples 5-16 and carrying out the reaction by the following procedures for step ii and step iii of Example 1.
A comparison of conversion of the acylating agent in Examples 25 and 26 show that HC1 pretreated catalyst has a higher activity than catalyst without pretreatment. EXAMPLES 27 and 28
These comparative examples illustrate the importance of pretreatment of the GazOa (20 wt%)Si-MCM-41 catalyst prepared in Example 2 by hydrogen chloride in step i. of the process of the invention for the acylation of toluene by benzoyl chloride.
The liquid phase acylation reaction over the catalyst was carried out by the procedure described in Example 2, except that the catalysts was not pretreated in step i. The results are included under Example 27 in Table 5. Whereas the results in Example 28 of Table 5 are for the catalyst pretreated in step i. according to the procedure described in Examples 5-16 and carrying out the reaction by the following procedures for step ii apd step iii of Example 2.
A comparison of conversion of the acylating agent in Examples 27 and 28 show that HC1 pretreated catalyst has a higher activity than catalyst without pretreatment
The observations and conclusions from. Examples 1 - 28 are given below:

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1 The pretreatment of the catalyst in the process of the invention is critical and essential to
activate the catalyst of the invention and thereby obtain high catalytic activity, i.e. high conversion of reactants in acylation reactions.
2. The catalyst of the invention shows high activity for the acylation of different aromatic
compounds even when there are no electron donating groups present in the aromatic
compound.
3. The catalyst of the invention shows very high activity for the acylation of aromatic
compounds even in the presence of moisture iathe reaction mixture.
4. The catalyst used in the process of the invention can be reused in the process.
5. TABLE 1: Results of acylation of different aromatic compounds

Example No. Example 1 Example 2 Example 3 Example 4
Catalyst Ga,O3 Ga2O, (20 wt%)/Si-MCM-41 In 2O3 Ga2O3In2O,(27 wt%)/Si-MCM-41
Reactants:
Aromatic compound (Ac) Benzene Toluene Benzene Toluene
Acylating agent (Aa) Benzoyl chloride Benzoyl chloride Benzoyl chloride Benzoyl bromdie
Reaction Conditions:
Solvent Nil Nil Nil Nil
Ac/Aa mole ratio 17.0 15 17.0 17.0
Solvent/ Aa mole ratio 0.0 0.0 0.0 0.0
Catalyst/ Aa weight ratio 0.33 0.6 0.33 0.33
Temperature (°C) 80 117 80 112
Pressure (atm) 1.0 1.8 1.0 1.1
GHSVofN2(h:f) 99 99 99 55
Reaction time (hours) 3.5 1.0 2.5 2.6
Conversion of Aa (%) 37.2 85 42.6 81.2
Main product of reaction C6H,COC6H, CH3C6H4COC6H, C6H,COC6H5 CH3C6H,COC6H,
Byproduct of reaction HC1 HC1 HCI HBr

TABLE 2: Results of the acylation of different aromatic compounds

Example No. Example 5 Example 6 Example 7 Example 8
Catalyst Ga2O3 Ga,oln2003 T12O(20 wt%)/SZ5564 Ga2O3O3(27 wt%)/Si-MCM-41
Reactants:
Aromatic compound (Ac) Benzene p-Xylene Toluene Durene
Acylating agent (Aa) Benzoyl chloride Benzoyl bromide Benzoyl chloride Benzoyl chloride
Reaction Conditions:
Solvent Nil Nil Nil Dichloroethane
Ac/Aa mole ratio 17.0 15 17.0 2.5
Solvent/ Aa mple ratio 0.0 0.0 0.0 20.0
Catalyst/Aa weight ratio 0.33 0.30 0.33 0.5
Temperature (°C) 80 140 110 80
Pressure (atm) 1.0 1.0 1.0 1.0
GHSV of N2 (If;1) 99 99 99 99
Reaction time (hours) 3.6 1.0 2.0 2.5
Conversion of Aa (%) 54.7 97 90.1 97.2
Main product of reaction C6H,COC6H? (CH3),C6H3COC6H, CHaC^COCifl, (CH3)4C6H4COC6H,
Byproduct of reaction HC1 HBr HC1 HBr

TABLE 2 CONTINUED

Example No. Example 9 Example 10 Example 1 1 Example 12
Catalyst Ga2O3(20 wt%)/Si-MCM-41 In203 (20 wt%)/Si-MCM-41 In203 (20 wt%)/Si-MCM-41 Ga, 13In, 87O3(8 wt%)/SA - 5205
Reactants:
Aromatic compound (Ac) Acylating agent (Aa) 2 - methoxy naphthalene Acetyl chloride 2 - Naphthol Acetyl chloride Phenol Benzoyl chloride Phenol Acetyl chloride
Reaction Conditions:
Solvent Dichloroethane Dichloroethane Dichloroethane Dichloroethane
Ac/Aa mole ratio 2.3 2.1 2.5 1.5
Solvent/ Aa mole ratio 21 20 23 16
Catalyst/ Aa weight ratio 0.33 0.1 0.33 0.3
Temperaiure ("C) 35 30 80 45
Pressure (atm) 1.0 1.0 1.0 13
GHSVofN2(h-') ' 85 90 110 115
Reaction time (hours) 0.6 1.5 0.25 0.8
Conversion of Aa (%) 98.7 96.2 993 98.3
Main product of reaction (CH30) C10H6COCH, (HO)C10H6COCH3 (HOjC^COCfcH, (HO)C6H4COCH3
Byproduct of reaction HC1 HC1 HC1 HC1

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—4
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TABLE 2 CONTINUED:

Example No. Example 13 Example 14 Example 15 Example 16
Catalyst In2O3(40 wt%)/H -beta Ga20In, 003 (3 wt%)/H-beta wt%)/Si-MCM-41 Feo6Ga12In,2O3(25 wt%)/Si-MCM-41
Reactants:
Aromatic compound (Ac) Phenol Phenol Mesitylene Naphthalene
Acylating agent (Aa) Acetic acid Phenyl acetyl chloride Benzoyl bromide Butyryl chloride
Reaction Conditions:
Solvent Nil Dichloroethane Nil Dichloroethane
Ac/Aa mole ratio 0.5 2.1 7.0 0.5
Solvent/ Aa mole ratio 0.0 18.0 0.0 15
Catalyst/ Aa weight ratio 0.5 0.9 0.8 1.0
Temperature (°C) 140 85 175 80
Pressure (atm) 1.0 1.2 1.4 1.3
GHSVofN2(h") 125 93 120 0.0
Reaction time (hours) 12.5 1.1 0.25 4.7
Conversion of Aa (%) 22.3 99.1 92.0 98.5
Main product of reaction (HO)C6H4COCH3 (HO)C6H4COCH2C6H, (CH3)3C6H,COC6H5 doHvCOC^
Byproduct of reaction H2O HC1 HBr HC1

TABLE 3: Results of the acylation of different aromatic compounds

Example No. Example 17 Example 18 Example 19 Example 20
Catalyst In2O3(20 wt%)/Si -MCM-41 Same as in Example 1 7 wt%)/Si-MCM-41 Same as in Example 19
Reactants:
Aromatic compound (Ac)
Acylating agent (Aa) Benzene Benzoyl chloride Benzene saturated with water Benzoyl chloride Toluene Benzoyl bromide Toluene saturated with water Benzoyl bromide
Reaction Conditions:
Solvent Nil Nil Nil Nil
Ac/Aa mole ratio 15.7 15.7 170 170
Sol vent/ Aa mole ratio 0.0 0.0 0.0 0.0
Catalyst/ Aa weight ratio 0.52 0.52 0.33 0.33
Temperature (°C) 80 80 112 112
Pressure (atm) 1.0 1.0 1.1 1.1
GHSVofN2(h4) 95 95 55 55
Reaction time (hours) 2.5 2.4 2.6 2.3
Conversion of Aa (%) 52.1 52.3 93.4 95.2
Main product of reaction C6H,CO C6H, C6H,COCeH, (CH,)C(,H4COChH, (CHOC()H4COC0H,
Byproduct of reaction HC1 HC1 HBr HBr

TABLE 4: Results showing the reusability of the catalyst of the invention for the process of the invention

Example No. Example 2 1 Example 22 Example 23 Example 24
Catalyst The catalyst after its The catalyst after its use in The catalyst after its The catalyst after its use in in
use in Example 19 Example 21 use in Example 16 Example 19
Reactants:
Aromatic compound (Ac) p-xylene Anisole Benzene Naphthalene
Acylating agent (Aa) Benzoyl chloride Butyryl chloride Benzoyl chloride Propionyl chloride
Reaction Conditions:
Solvent Nil Nil Nil Nitromethane
Ac/Aa mole ratio 17.9 16.5 17.1 2.0
Solvent/ Aa mole ratio 0.0 0.0 0.0 15.0
Catalyst/ Aa weight ratio 0.3 0.25 0.8 0.5
Temperature (°C) 140 163 87 103
Pressure (atm) 1.0 1.3 1.5 1.2
GHSVofN2(h') 105 95 97 91
Reaction time (hours) 1.0 1.5 9.0 2.8
Conversion of Aa (%) 97.9 97.5 98.4 98.6
Main product of reaction (CH3)2C6H3COC6H, (CH,0)C6H4COC4H9 C6H,COC6H, CIOH7COC,H7
Byproduct of reaction HC1 HC1 HC1 HC1

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-4
TABLE 5: Results of acylation of different aromatic compounds with and without pretreatment of catalyst.

Example No. Example 25 Example 26 Example 27 Example 28
Catalyst In2O, ln2O3 Ga,O3 (20 wt%)/Si -MCM-41 Ga2O3 (20 wt%)/Si -MCM-41
Reactants:
Aromatic compound (Ac) Benzene Benzene Toluene Toluene
Acylating agent (Aa) Benzoyl chloride Benzoyl chloride Benzoyl chloride Benzoyl chloride
Reaction Conditions:
Solvent Nil Nil Nil Nil
Ac/Aa mole ratio 17.0 170 15 15
Solvent/ Aa mole ratio 0.0 0.0 0.0 0.0
Catalyst/ Aa weight ratio 0.33 0.33 0.6 0.6
Temperature (°C) 80 80 117 117
Pressure (atm) 1.0 1.0 1.8 1.8
GHSVofN2(h") 99 99 99 99
Reaction time (hours) 2.6 2.8 1.0 1.0
Conversion of Aa (%) 31.3 52.5 77 95.1
Main product of reaction C6H,COC6H, C(,H,COC6H? CH,C6H4COC6H5 CH,C6H,COC6H,
Byproduct of reaction HC1 HC1 HCI HCI

NF 47/01
Advantages of the invention:
The process of the invention has the following advantages over the prior art homogeneous acid catalysed processes for the acylation of aromatic compounds. 1 The catalyst used is a heterogeneous solid catalyst and hence can be separated from the reaction products simply by filtration.
2. The separated catalysts can be reused a number of times in the process of the invention.
3. The catalyst is non-corrosive.
The process of the invention can be differentiated from prior art processes bsed on the use of solid acid catalyst for the acylation of aromatic reactions.
1. The activity of the catalyst used in the invention is high thereby increasing the speed of
reaction and reducing the time required for completion of the reaction.
2. The catalyst of the invention can be reused a number of times in the process of the
invention and shows high activity in the process even after repeated use.
3. The process of the invention can be used for the acylation of both small and large size
aromatic compounds with both small and large sized acylating agents to obtain the
corresponding acylated aromatic compounds.
4. When the inert gas is bubbled through the reaction mixture continuously, the byproduct
formed is removed continuously thereby preventing or minimising the reverse acylation
reaction This results in speeding up of the time required for the reaction.
5. By using pressures of greater than or equal to 1 atm., the reaction can be carried out at
temperatures higher than the normal boiling point of either the reactants or the solvent,
thereby shortening the reaction period. The inhibition of the reaction is avoided or
minimised due to strong adsorption of the reactants, products or solvent on the catalyst.
6 The process of the invention is effective even for the acieration of benzene which does not contain any aromatic ring activating electron donating group such as alkyl, alkoxy, hydroxy, etc. The rate of reaction is rapid at mild reaction conditions and hence the time for reaction is short.
7. The process of the invention results in rapid acylation of aromatic compounds even when the reaction mixture contains moisture. The catalyst is not deactivated due to the presence of moisture in the reaction mixture. Thus, unlike prior art homogeneous and solid acid catalysts, the catalyst of the invention does not require moisture, free conditions tdTje active. This results in saving of costs towards removal of moisture from the reaction system or the reactants.

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8. The catalyst of the invention is acidic and basic in nature, the process of the invention can
be used for acylating both acid sensitive aromatic compounds and basic aromatic compounds.

We Claim:
1. An improved process for the liquid phase acylation of an aromatic compound of the formula (RiR2R3R4) - M - H by an acylating agent of the formula (R5R6R7) -Y - Z to obtain the corresponding acylated compound of the formula (RiR2R3R4) - M-Y-(R5R6R7) wherein M is an aromatic nucleus with R1R2R3, and R4 being the chemical groups as herein described attached thereto, Y is the nucleus of the acylating agent and is selected from the group consisting of C - CO, CnH2n-2CO, C6H2CnH2n-2CO and C6H2CnH2n-i(X)-CO, R5, R6 and R7 being chemical groups as herein described attached thereto Y, Z is selected from the group consisting of Cl, Br, I and OH, X is halogen, and n is an integer having a value equal to or greater than 1.0, using a solid catalyst comprising a metal oxide of the formula AOx, with or without a catalyst support as herein described wherein A is a metallic element selected from Ga, In, Tl, Fe and a mixture of two or more thereof, and x is the number of oxygen atoms required to fulfill the valance requirement of A, said process comprising,
i. pretreating the solid catalyst by contacting it with a dry gas comprising a hydrogen halide optionally in the presence of the aromatic compound to be acylated.
ii. contacting the hydrogen halide pretreated catalyst with a liquid reaction mixture comprising the aromatic compound and the acylating agent in a stirred batch reactor at following reaction conditions weight ratio of catalyst to acylating agent in the range 0.01 to 2.0, mole ratio of the aromatic compound to the acylating agent in the range of 0.1 to 100, weight ratio of non-aqueous solvent to the aromatic compound being in the range of 0 to 100, reaction temperature being in the range of 10°C to 300°C, pressure in the range of 0.5 atm to 10 atm., gas hourly space velocity of inert gas bubbled through the reaction mixture being in the range of 0.1 h"1 to 5OOOh"1 and reaction period in the range of from 0.02 hours to 100 hours;
iii. cooling the reaction mixture to a temperature of 30°C, removing the catalyst from the reaction mixture by filtration and then separating the reaction products from the reaction mixture.

2. A process as claimed in claim 1 wherein R1, R2, R3 and R4 are each selected from
hydrogen, alkane, olefinic, phenyl, alkoxy, phenoxy, hydroxyl, aldehydic,
halogen, ketonic, amine, amide, thio, and sulphonic acid groups.
3. A process as claimed in claims 1 and 2 wherein Z comprises Cl, Br, or OH.
4. A process as claimed in any preceding claims wherein each of Rs, R6, and R7is
selected from the group consisting of hydrogen, alkane, olefinic, phenyl, halogen,
nitro and cyano groups.
5. A process as claimed in any preceding claims wherein A is selected from the
group consisting of Ga, In and TI and a mixture of any two or more thereof.
6. A process as claimed in any preceding claims wherein the hydrogen halide used
in step ii is selected from HC1 gas and HBr gas.
7. A process as claimed in nay preceding claims wherein the weight ratio of the
catalyst to the acylating agent is in the range of 0.03 to 0.09.
8. A process as claimed in any proceeding claims wherein the mole ratio of the
aromatic compound to the acylating agent is in the range of 1.0 to 20.
9. A process as claimed in any preceding claim wherein the weight ratio of the non-
aqueous solvent to the aromatic compound is in the range of 0 to 20.
10. A process as claimed in any proceeding claims wherein the reaction temperature
is preferably in the range of 20°C to 200°C.
11. A process as claimed in any preceding claim wherein the reaction pressure is
preferably in the range of 1 atm to 5 atm.
12. A process as claimed in any preceding claim wherein the reaction period is
preferably in the range of 0.05 hours to 20 hours.
13. A process as claimed in any preceding claim wherein the space velocity of inert
gas is preferably in three range of 50h"1 to 5OOh'1.
14. A process as claimed in any preceding claim wherein M is selected from the
group comprising a single aromatic ring containing 6 C atoms and 1 H atom,
fused two aromatic rings containing 10 C atoms and 3 H atoms, and three fused
aromatic rings containing 14 C atoms and 5 H atoms.
15. A process as claimed in nay preceding claim wherein the used catalyst is washed
with a non-aqueous solvent or the aromatic compound and recycled directly with
or without drying to step ii.
16. A process as claimed in claim 1 wherein R1, R2, R3 and R4 are each selected from
the group consisting of H, CnH2n-i, CmH2m+1C6H5, CnH2nC6H55 OH, OCnH2n-i, O
C6H5, halogen, NO2, NH2, NH CnH2n+1> N(CnH2n.+1)2, NHCO CnH2n+,,
NHCOC6H5, CN, CHO, COOH, COOCnH2n.i, SO3H, SO3CnH2n+iSH, alkyl
mercapto and aryl mercapto wherein n and m are integers greater than or equal to
1 and 2 respectively.
17. A process as claimed in claim 1 wherein each of R5, Re, and R7 is selected from
the group consisting of H, CH3, C2H5, OH, OCH3, OC2H5, NO2, halogen and
NH2.
18. A process as claimed in any preceding claims wherein the reaction time period is
preferably in the range of 0.1 hours to 20 hours.
19. A process as claimed in any proceeding claims wherein the weight ratio of the
catalyst to the acylating agent is in the range of 0.1 to 1.
20. A process as claimed in any proceeding claims wherein the mole ratio of the
aromatic compound to the acylating agent is in the range of 0.5 to 20.
21. A process as claimed in any proceeding claims wherein Z is Cl or Br.
22. A process as claimed in any preceding claims wherein M is Ga or In or a mixture
thereof.
23. A process as claimed in any preceding claim wherein the catalyst is supported on
a meso or macroporous catalyst carrier selected from alumina, silica, silica-
alumina, inert metal oxides, zeolites, and zeolite like materials.
24. A process as claimed in claim 23 wherein the catalyst support comprises a
microporous zeolite material having pore size less than or equal tol.Onm selected
from the group consisting of zeolite X, zeolite Y, mordenite, Zeolite L, zeolite
beta, ZSM 5, ZSM 8 and ZSM 11.
25. A process as claimed in claim 23 wherein the catalyst support comprises a
mesoporous zeolite material having pore size in the range of 1.5 mnm to 50 nm
selected from the group consisting of M41S type material and MCM41.
26. A process as claimed in any preceding claim wherein the solvent when used is
selected from the group consisting of dichloroethane, nitrobenzene, nitromethane,
chlorobenzene, n-hexane, n-heptane and n-octane
27. An improved process for the liquid phase acylation of aromatic compounds
substantially as described hereinbefore and with reference to the foregoing
examples.

Documents:

372-del-2001-abstract.pdf

372-del-2001-claims.pdf

372-del-2001-correspondence-others.pdf

372-del-2001-correspondence-po.pdf

372-del-2001-description (complete).pdf

372-del-2001-form-1.pdf

372-del-2001-form-18.pdf

372-del-2001-form-2.pdf

372-del-2001-form-3.pdf

372-del-2001-petition-138.pdf

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Patent Number

231559

Indian Patent Application Number

372/DEL/2001

PG Journal Number

13/2009

Publication Date

27-Mar-2009

Grant Date

06-Mar-2009

Date of Filing

27-Mar-2001

Name of Patentee

COUNCIL OF SCIENTIFIC AND INDUSTRIAL RESEARCH

Applicant Address

RAFI MARG, NEW DELHI-110 001, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	VASANT RAMCHANDRA CHOUDHARY	INDIAN NATIONALS FORM NATIONAL CHEMICAL LABORATORY, PUNE 411 008, MAHARASHTRA, INDIA,
2	SUMAN KUMAR JANA	INDIAN NATIONALS FORM NATIONAL CHEMICAL LABORATORY, PUNE 411 008, MAHARASHTRA, INDIA,

PCT International Classification Number

C07C 45/45

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA