Title of Invention | "A PROCESS FOR THE PREPARATION OF HYDROXY BENZYL ALCOHOLS" |
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Abstract | This invention relates to an improved process for the preparation hydroxybenzyl alcohols which comprises reacting phenol over a microporous alumino silicate zeolite catalyst composite material such as herein described in the presence of hydroxy methylating agent at a temperature in the range of 20°C to 200°C for a period in the range of 0.1 to 24 hours at atmospheric pressure and collecting hydroxybenzylalcohol by conventional methods. |
Full Text | The present invention relates to a process for producing hydroxybenzylalcohols. More particularly, it relates to a process for producing ortho-hydroxybenzylalcohol with high selectivity by the reaction of phenol with formaldehyde with the use of a novel catalyst.' Hydroxy benzyl alcohols are useful as intermediates for agrochemicals, drugs, antioxidants or modifier for resins. Accordingly, there have been various studies for the manufacture of hydroxy benzyl alcohols. As a process for the liquid phase hydroxymethylation of phenol it has been common to conduct the hydroxymethylation in the presence of Lewis acid catalysts. It is normally obtained by heating a mixture of phenol, cyclohexanol, paraformaldehyde and Zn(Oac)2.2H2O at 80°C for 2 h to obtain 49.9 % of ortho-hydroxy benzyl alcohol (Jpn.Kokai Tokkyo Koho JP 05,271,134; Chem.Abstr. 120:191330). In another method, para-hydroxy benzyl alcohol has been selectively synthesized from phenol and formaldehyde by the use of hydroxypropyl cyclodextrins as catalyst (J.Chem.Soc.Perkin Trans I, 2031, 1989). In another method, the selective synthesis of para-hydroxy benzyl alcohol from phenol and formaldehyde is successfully achieved in a 0.75 N aq. NaOH solution at 30°C by use of B-cycloclextrin as catalyst (J.Moi.Catal. 51(4), 137, 1989). Hydroxymethylation of phenol wiili formaldehyde in an aq. NaOH in the presence or the cyclodextnn gave para- and orlho- hydroxy benzyl alcohol. with a para : ortho ratio up to 15.7. In the absence of cyclodextnn, the para : ortho ratio was 2:1 (J.Chem.Soc.Chem.Commun. 651, 1988). In one method, ortho-hydroxy benzyl alcohol is prepared by hydroxymethylation of phenol with formaldehyde in the presence of Zn(Oac)2.2H2O at 60°C to give a crude product containing ortho-hydroxy benzyl alcohol 63.9 % (Jpn. Kokai Tokkyo Koho JP 62,240.638). Ortho-hydroxy benzyl alcohol was also prepared by condensing phenol with formaldehyde or its derivatives in the presence of Zn(OAc)2 or boric acid at 70°C to give a reaction mixture containing 30.01 wt.% of ortho-hydroxy benzyl alcohol (Jpn. Kokai Tokkyo Koho JP 59,65 034). A method comprising reacting phenol with para-formaldehyde in the presence of basic catalyst speciticaily diamines (Me2NCH2)2 at 70°C gave 599c ortho- and 41.4 % para-hydroxy benzyl alcohols (Ger.Offen. 2,928,554; Chem.Abstr. 94:179643). A method comprising base catalyzed hydroxymethylation of phenol with formaldehyde to ortho- and para-hydroxy benzyl alcohols is promoted by polyethers. Thus phenol with para-formaldehyde and catalytic amount of 50% KOH and poly ethylene glycol gave a mixture containing 53.4% ortho- and 46.6 % para hydroxy benzyl alcohol (Chem.Abstr. 94:83756). The use of homogeneous catalysts, however, presents a number of drawbacks. The homogeneous catalyst is used in large amounts at least equal to the stoichiornetric amount and at the end of the reaction it is difficult to separate the homogeneous catalyst from the product, A lengthy and expensive treatment is to be carried for the separation of aqueous and organic phase and hence separation of the homogeneous catalysts is a long and expensive process. Further, the selectivity for ortho-hyclro.xybenzyl alcohol is low in some cases. Still further the homogeneous catalyst can not be recycled. In view of the above mentioned homogeneous catalysts and low selectivity for ortho-hydroxy benzyl alcohol in the prior art process , it was found desirable during the course of the research work leading to the present invention to develop an improved process for the production of hydroxy benzyl alcohols and particularly ortho-hydroxy benzyl alcohol in high selectivity from by the hydroxymethylatioft of phenol with formaldehyde in the presence of solid catalyst composite material aluminosilicate zeolite catalyst. Accordingly a major object of the present invention is the provision of an improved process for the hydroxymethylation of phenol, characteristically into hydroxybenzylalcohols and which novel process avoids or conspicuously ameliorates the above disadvantages and the drawbacks to date characterizing the state of this art. Accordingly the present invention provides an improved process for the preparation of hydroxybenzyl alcohols which comprises reacting phenol over a microporous alumino silicate zeolite catalyst composite material such as herein described in the presence of hydroxy methylating agent at a temperature in the range of 20°C to 200° C for a period in the range of 0.1 to 24 hours at atmospheric pressure and collecting hydroxybenzylalcohol by conventional methods. In one of the embodiment of the present invention the zeolite catalyst used in the reaction is K-ZSM-5 or K- modernite or K-Y or K- beta or K-L. In one of the embodiment of the present invention the zeolite catalyst used in the reaction may contain ion exchange cations such as sodium, cesium or rubidium, but may further include other cations of the group IA,IIA, III A or VA of the periodic table. The cations may be of the same type or of two or more different types. In another embodiment of the present invention the hydroxymethylating agent used may be such as aqueous formaldehyde or para formaldehyde or trioxane, preferably para-formaldehyde. la yet another embodiment of this invention the ratio of phenol to the hydroxymethylating agent is 1:1 to 10:1 preferably 5:1. In a feature of the present invention it is possible to selectively and efficiently prepare the ortho-hydroxybenzylalcohol. The reactants which are employed in the process of the present invention are desired to be high in purity. In the present invention, the zeolite may be added to the reactant in a manner as follows: 1) The zeolite and the phenol may be combined and added to the hydroxymethylating agent prior to the reaction. 2) The zeolite and phenol may be added simultaneously to the reaction system at the time of reaction. 3) The zeolite is suspended in the phenol and then a predetermined amount of the hydroxymethylating agent is added thereto. Another feature of the present invention is that the reaction is carried out at a relatively low temperature between 20 and 200°c. Yet another feature of the process of the present invention is the use of the non-hazardous solid aluminosilicate catalysts. Another feature of the process of the present invention is that it does not pose risk of explosion. Thus, the process of the present invention is suitable as an industrial process for the production of ortho-hydroxybenzylalcohol in high selectivity. The present invention is described hereinbelow by examples which are illustrative only ana should not be construed to restrict the scope 01 the invention. Example 1 This example illustrates the procedure for the hydroxymethylation of phenol with para - formaldehyde to ortho-hydroxybenzylalcohol, para-hydroxyben/.ylalcohol and dihydroxydiphenylmethane. 500 g (5.3 mol) of phenol was reacted with 32 g of reacted with 32 g of para-formaldehyde in the presence of activated 1 g catalyst composite material zeolite K-L at SO°C for one hour under stirring in a batch reactor. After the reaction, the reaction mixture cooled to room temperature, filtered off and analyzed by gas- chromatography. The results are listed in Table 1. Table 1: Hydroxymethylation of phenol with para-formaldehyde over catalyst composite material aluminosilicate zeolite K-L after one hour. (Table Removed) Example 2 This example illustrates the procedure for the hydroxymethylation of phenol with aqueous formaldehyde to ortho-hydroxybenzy] alcohol, para-hydroxybenzyl alcohol and dihydroxydiphenylmethane. The reaction was carried out in liquid phase using batch reactor. 250 g (2.7 mol) of phenol was reacted with 43.7 g (0..54 mol) aqueous formaldehyde (37%) using Ig of activated catalyst composite material zeolite K-ZSM-5 at 80°C for three hours. After the completion of the reaction, the reaction mixture cooled to room temperature and catalyst was filtered off. Thus the reaction mixture obtained was analyzed by gas- chromatography. The results are listed in Table 2. Table 2. Hydroxymethylation of phenol with aqueous formaldehyde over catalyst composite material aluminosilicate zeolite K-ZSM-5 after three hours. (Table Removed) Example 3 This example illustrates the procedure for the hydroxymethylation of phenol with aqueous formaldehyde to ortho-hydroxybenzylalcohol , para-hydroxybenzylalcohol.-And dihydroxydiphenylmethanes. The reaction was carried out in liquid phase using batch reactor. 25g (0.27mo!) of phenol was reacted with 4.31g (0.14mol) aqueous formaidehyde(37%) using Ig of activated catalyst composite material zeolite K-Mordenite at 80° C for six hours. After the completion of the reaction, the reaction mixture cooled to room temperature and catalyst was filtered off. Thus the reaction mixture obtained was analysed by gas-chromatography. The results are listed in Table 3 Table 3 : Hydroxymethylation of phenol with aqueous formaldehyde over catalyst composite material aluminosilicate zeolite K-Mordenite after six hours (Table Removed) Example 4 This example illustrate- the procedure for the hydroxymethylation of phenol with aqueous formaldehyde to ortho-hydroxybenzylalcohol , para-hydroxybenzylalcohol. And dihydroxydiphenylmethanes. The reaction was carried out in liquid phase using batch reactor. 25g (0.27mol) of phenol was reacted with 4.3Ig (0.14mol) aqueous forrnaldehyde(37%) using Ig of activated catalyst composite material zeolite K-Y at 80° C for six hours. After the completion of the reaction, the reaction mixture cooled to ruuin temperature and catalyst was filtered off. Thus the reaction mixture obtained was analysed by gas-chromatography. The results are listed in Table 4 Table 4. Hydroxymethylation of phenol with aqueous formaldehyde over catalyst composite material aluminosilicate zeolite K-Y after six hours. (Table Removed) Example 5 This example illustrates the procedure for the hydroxymethylation of phenol with aqueous formaldehyde to ortho-hydroxybenzyl alcohol , para- hydroxybenzylalcohol. And dihydroxydiphenylmethanes. The reaction was carried out in liquid phase using batch reactor. 25g (0.27mol) of phenol was reacted with 4.3 Ig (0.14mol) aqueous formaldehyde(37%) using Ig of activated catalyst composite material zeolite K-X at 80° C for two hours. After the completion of the reaction, the reaction mixture cooled to room temperature and catalyst was filtered off. Thus the reaction mixture obtained was analysed by gas-chromatography. The results are listed in Table 5 Table 5. Hydroxymethylation of phenol with aqueous formaldehyde over catalyst composite material aluminosilicate zeolite K-X after two hours. (Table Removed) Example 6 This example describes the effect of the hydroxymethylating agent in the reaction of phenol with para-formaldehyde on the conversion of phenol and selectivity for ortho-hydroxybenzylalcohol . para-hydroxybenzylalcohol. and dihydroxydiphenylmethanes. The reaction was carried out in liquid phase using batch reactor. 25g (0.27mol) of phenol was reacted with 1.6g of para-formaldehyde in the presence of activated Ig catalyst composite material zeolite K-L at 80° C for one hour under stirring in a batch reactor. After the of the reaction, the reaction mixture cooled to room temperature and catalyst was filtered off. Thus the reaction mixture obtained was analysed by gas-chromatography. The results are listed in Table 6 Table 6. Effect of hydroxymethylating agent (para-formaldehyde) in the hydroxymethylation of phenol over catalyst composite material aluminosilicate zeolite K-L after one hour. (Table Removed) Example 7 This example describes the effect of the hydroxymethylating agent in the reaction of phenol with aqueous-formaldelv.de on the conversion of phenol and selectivity for ortho-hydroxybenzylalcoho) , para-hydroxybenzylalcohol. and dihydroxydiphenylmethanes. The reaction was carried out in liquid phase using batch reactor. 25g (0.27mol) of phenol was reacted with 4.3Ig (0.14mol) of aqucous-formaldehyde in the presence of activated Ig catalyst composite material zeolite K-L at 80° C for one hour under stirring in a batch reactor. After the of the reaction, the reaction mixture cooled to room temperature and catalyst was filtered off. Thus the reaction mixture obtained was analysed by gas-chromatography. The results are listed in Table 7 Table 7. Effect of hydroxymethylating agent (aqueous-formaldehyde) in the hydroxymethylfttion of phenol over catalyst composite material aluminosilicate zeolite K-L after one hour. (Table Removed) The advantages of the present invention are, 1. The resulting advantages are that a corrosion free plant can be used. 2. A recyclable zeolite catalyst can be used. 3. The problem of the need to dispose of inorganic byproducts does not arise. 4. The process of the present invention shows remarkably high industrial merits over prior art process for the preparation of orthohydroxybenzylalcohol. The starting materials are easily available and easy to handle. We Claim: 1. An improved process for the preparation of hydroxybenzyl alcohols which comprises reacting phenol over a microporous alumino silicate zeolite catalyst composite material such as herein described in the presence of hydroxy methylating agent at a temperature in the range of 20°C to 200° C for a period in the range of 0.1 to 24 hours at atmospheric pressure and collecting hydroxybenzylalcohol by conventional methods. 2. An improved process as claimed in claim 1 wherein the hydroxymethylating agent used is formaldehyde, paraformaldehyde or trioxane. 3. An improved process as claimed in claim 1 and 2 wherein the zeolite catalyst composite material used is zeoliteK-ZSM-5, K- mordenite, K-Y, K-L . 4. An improved process for the preparation of hydroxybenzyl alcohols as substantially described herein before with reference to the examples contained therein. |
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293-del-2000-complete specification (granted).pdf
293-DEL-2000-Correspondence-Others.pdf
293-DEL-2000-Correspondence-PO.pdf
293-DEL-2000-Descirption (Complete).pdf
Patent Number | 191516 | |||||||||
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Indian Patent Application Number | 293/DEL/2000 | |||||||||
PG Journal Number | 49/2003 | |||||||||
Publication Date | 06-Dec-2003 | |||||||||
Grant Date | 30-Jun-2004 | |||||||||
Date of Filing | 23-Mar-2000 | |||||||||
Name of Patentee | COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH | |||||||||
Applicant Address | RAFI MARG, NEW DELHI-110001, INDIA. | |||||||||
Inventors:
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PCT International Classification Number | C07C 37/20 | |||||||||
PCT International Application Number | N/A | |||||||||
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PCT Conventions:
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