Title of Invention

"A PROCESS FOR PREPARATION OF ALKYLATED DIHYDROXY BENZENE"

Abstract

The present invention relates to a process for preparation of alkylated dihydroxy benzene. The alkylated di-hydroxy benzenes are used as antioxidant, polymer stabilizers and in the treatment of mitochondrial respiration ailments, by the alkylation of dihydroxy benzene over solid acid or polyaniline sulfate as catalyst in the presence of tertiary butyl alcohol. The process steps are: alkylating dihydroxy benzene with tertiary butyl alcohol in presence solid acid or polyaniline-sulfate catalyst in the temperature range from 40 to 90°C for a period of 2 to 8 hrs, separating the alkylated dihydroxy benzene by conventional method from the reacting mixture.

Full Text

The present invention relates to a process for preparation of alkylated dihydroxy benzene. The present invention more particularly relates to a process for producing alkylated di-hydroxy benzenes which are used as antioxidant, polymer stabilizers and in the treatment of mitochondrial respiration ailments, by the alkylation of dihydroxy benzene over solid acid or polyaniline sulfate as catalyst in the presence of tertiary butyl alcohol. Friedel-Crafts catalysis is one of the major and industrially important processes and widely used in the synthesis of low and high volume chemicals. Acylations, benzylations, alkylations and sulphonylations giving a wide range of useful products like ketones, alcohols, alkyl aromatics and sulphones are included in this name reaction. Petrochemical industry is also a beneficiary of this class of reaction, where a number of alkyl hydrocarbons are synthesized by alkylation reactions. The conventional catalysts used in these reactions are A1C13, HF, H2SO4, BF3 and BPO4 the likes. Most of the batch processes use A1C13 as soluble acid catalyst which is inexpensive, very reactive and is one of the most powerful Lewis acids. Unfortunately, it is difficult to handle A1C13 and similar metal halides as catalysts since they get readily hydrolyzed. Very often such catalysts are required in stoichiometric quantities. A large inventory of these materials pose health, safety and storage problems. Furthermore, the traditional route of liquid phase alkylation using mineral acids and A1C13 as catalysts suffer from the disadvantages of high capital cost, reactor corrosion, formation of by-products and the difficulty in catalyst regeneration. In recent times, the scientist's world wide have been devoting their attention to the development of environmentally friendly catalysts for the production of intrinsically important chemicals and chemical intermediates. The use of safe solid acids in place of traditional Friedel-Crafts catalysts and mineral acids has become important. Several alkylation reactions of aromatic hydrocarbons and functional aromatic hydrocarbons have been tried out over zeolites, oxides, mixed oxides and supported oxides. Clays such as montmorillonite having acidic functions are also being considered as alternative catalysts for these reactions. Clays have also been modified for this purpose by pillaring with polyhydroxy metal cations such as Zr, Al, Cr, Ga etc. acid activation, ion exchange with transition metals and by metal oxide impregnation. • Alkylation of phenols are important chemicals and chemical industries, especially in agrochemical and pharmaceutical industries (Fiege et al, in Gehartz W.et al eds, 1987 - Valmann Encyclopedia of Industrial Chemistry, 5th Editon, Wemheim, VCH Verlagsglsellaschaft; Lowenheim F.A. et al. 1975 Industrial chemicals; A. Wiley Interscience, New York; Kirk J. et al 1981, Encyclopedia of Chemical Technology, 3rd Edition, Wiley, New York). Alkylation of phenol with methanol over various catalysts has been studied (Nozaka et al. Bull. Chem. Soc. Japan. 50, 1997, 614; Narayanan et al. J. Mol. Catal. 52, 1987, 129; Velu et al. React. Kinetic. Catal. Lett. 62(2), 1997, 339 and Appl. Catal. A. General 119, 1994, 241.) Alkylation of phenol with alcohol over thoria was studied (Karuppanasamy et al., J. Catal. 63, 1980, 433) Alkylation of phenol with 2-propanol was investigated over alumina (Klemm et al., J. Org. Chem.. 45. 1980, 4326), Alkylation of phenol with isopropanol over zeolite catalyst was examined (Guo Changwen et al., Beijing Huagon Yanjuyuan. 27(3), 1998, 163), tertiary butylation of phenol was carried out over acid catalyst (Corma et al. J. Catal. 134, 1992, 58 and Appl. Catal. 105, 1993, 271) and tertiary butylation of phenol over zeolite solid acid catalyst was investigated in vapour phase (Peimo et al. Huadong Huadong Xueynan Xuebao. 14 (4), 1998, 476; Chang et al. US 5,288,927, 1993 and Kuizhang et al, Appl. Catal. A General. 166, 1998, 89). Alkylation of dihydroxy benzene with tertiary butyl alcohol was investigated by Korneev et al (USSR Patent No. 1,583,407, 1990) using mineral acids. The drawbacks of using mineral acid as catalyst as given in the referred works are: (i) Catalyst can not be reused, (ii) Disposal of acid is not environmentally safe and it is not economical, (iii) Low selectivity is frequently observed, (iv) Corrosion of the reaction vessel and reactors, (v) Not easy to handle and (iv) High inventory of the catalyst. The main object of the present is to provide a process for preparation of alkylated dihydroxy benzene with tertiary butyl alcohol using solid acid or polyaniline-sulfate as catalyst which obviates the drawbacks as detailed above. Another object of the present invention is to use solid acid or polyaniline-sulfate as catalyst for alkylation reaction. Accordingly, the present invention relates to a process for preparation of alkylated dihydroxy benzene which comprises; alkylating dihydroxy benzene with tertiary butyl alcohol in presence solid acid or polyaniline-sulfate catalyst in the temperature range from 40 to 90°C for a period of 2 to 8 hrs, separating the alkylated dihydroxy benzene by conventional method from the reacting mixture In an embodiment of the present invention, the dihydroxy benzene used may be selected from resorcinol, hydroquinone and catechol. In an another embodiment of the present invention, the catalysts used may be selected from zeolites of types HZSM-5 (SiO2/Al2O3 = 30), HY (SiO2/ A12O3 = 5.2), H-MORDENITE (HM) (SiO2/ A12O3 = 20), MCM-41, MONTMORINLLONITE-K10 CLAY, ALUMINA or polymer of type polyaniline-sulfate. In yet another embodiment of the present invention, the reaction may be carried out in the temperature from 60 to 90°C. In still yet another embodiment of the present invention, the reaction may be carried out for a period of 6 to 8 hrs. These embodiments will be apparent from the ensuing detailed description of the present invention. The process of alkylating dihydroxy benzene may be carried out reacting dihydroxy benzene with tertiary butyl alcohol in presence of catalyst, removing the catalyst by conventional method such as filtration followed by isolation of alkylated products by conventional column gromatography using adsorbent such as silica gel, alumina and solvent such as chloroform, ethylacetate, hexane and mixture there off. The following examples are given by way of illustration and therefore should not be construed as limit the scope of the present invention. EXAMPLE 1 In a typical experiment, 2.8 ml of tertiary butyl alcohol was taken in 50 ml round bottom flask and added 1 g of resorcinol and 200 mg of catalyst powder. The reaction mixture was refluxed at 80° C for 8 hrs. Filtered the reaction mixture and analyzed the filtrate using a CHEMITO 8510 Gas Chromatography using 20 % SE-30 column, coupled with flame ionization detector for product distribution. A typical Gas Chromatography - Mass spectral fragmentation pattern and Proton Nuclear Magnetic Resonance spectra (1HNMR) of the products proves that the products obtained were the mixture of mono and dialkylated benzene. The reaction was carried out using different solid acid catalysts and the conversion and selectivities are given in Table-1. TABLE - 1 CONVERSION AND SELECTIVITIES USING DIFFERENT SOLID ACID CATALYSTS (Table Removed) EXAMPLE 2 In a typical experiment, 2.8 ml of tertiary butyl alcohol was taken in 50 ml round bottom flask and added 1 g of resorcinol and 200 mg of catalyst powder. The reaction mixture was refluxed at 80° C for 2, 4, 6 and 8hrs. Filtered the reaction mixture and analyzed the product The reaction was carried out using modified montomorinllonite-K10 solid acid catalyst and the conversion and selectivities are given in Table-2. TABLE - 2 CONVERSION AND SELECTIVITIES WITH REACTION TIME (Table Removed) EXAMPLE 3 In a typical experiment, 2.8 ml of tertiary butyl alcohol was taken in 50 ml round bottom • flask and added 1 g of resorcinol and 200 mg of catalyst powder. The reaction mixture was refluxed at 80° C for 8 hrs. The temperature of the reaction was varied from 60 to 90°C in steps of 10°C. Filtered the reaction mixture and analyzed the product. The reaction was carried out using modified montomorinllonite-K10 solid acid catalyst and the conversion and selectivities are given in Table-3. TABLE - 3 CONVERSION AND SELECTIVITIES WITH TEMPERATURE (Table Removed) EXAMPLE 4 In a typical experiment, 2.8 ml of tertiary butyl alcohol was taken in 50 ml round bottom flask and added 1 g of resorcinol and 200 mg of catalyst powder. The reaction mixture was refluxed at 80° C for 8 hrs. The mole ratio of resorcinol to tertiary butyl alcohol was varied as 1:3, 1:5, 1:7 and 1:9. Filtered the reaction mixture and analyzed the product. The reaction was carried out using modified montomorinllonite-K10 solid acid catalyst and the conversion and selectivities are given in Table-4. TABLE - 4 CONVERSION AND SELECTIVITIES WITH MOLAR RATIO (Table Removed) EXAMPLE 5 In a typical experiment, 2.8 ml of tertiary butyl alcohol was taken in 50 ml round bottom flask and added 1 g of hydroquinone and 200 mg of modified montomorinllonite-K10 solid acid catalyst powder. The reaction mixture was refluxed at 80° C for 8hrs. The conversion of hydroquinone was found to be around 57 %. EXAMPLE 6 In a typical experiment, 2.8 ml of tertiary butyl alcohol was taken in 50 ml round bottom flask and added 1 g of catechol and 200 mg of modified montomorinllonite-K10 solid acid catalyst powder. The reaction mixture was refluxed at 80° C for 8hrs. The conversion of hydroquinone was found to be around 45 %. EXAMPLE 7 In a typical experiment, 2.8 ml of tertiary butyl alcohol was taken in 50 ml round bottom flask and added 1 g of resorcinol and 200mg of polyaniline-sulfate (Preparation see Composition and spectral studies of polyaniline salts, S. Palaniappan, Polymers for Advanced Technology. 5, 1994, 225) catalyst. The reaction mixture was refluxed at 80° C for 8 hrs. Filtered the reaction mixture and analyzed the product. The conversion and selectivities are given in Table-5. TABLE - 5 CONVERSION AND SELECTIVITIES WITH MOLAR RATIO (Table Removed) The main advantages of the present invention are : the use of solid acid catalysts as well as polyaniline-sulfate as solid acid/solid polymer catalyst in the liquid phase alkylation of dihydoxy benzene with tertiary butyl alcohol for the first time. Also, the use of solid acid catalyst provides the following advantages compared with the use of mineral acid catalyst (i) high catalytic activity and selectivity are frequently observed, (ii) solid acid catalyst do not corrode reaction vessel or reactors, (iii) repeated use of solid acid catalyst is possible, (iv) allowing recycling of catalyst, (v) improving turn over frequency, (vi) separation of solid acid catalyst from a reaction mixture is easy and (vii) there is no problem for the disposal of used solid acid catalyst as they are environmentally safe, though the disposal of mineral acid catalyst requires much money for treatment to make it environmentally safe. In view of the above, it will be seen that several advantages of the invention are achieved and other advantageous results attained. As various changes could be made in the above methods and compositions without departing from the scope of the invention, it is intended that all matter contained in the above description shall be interpreted as illustrative and not in a limiting sense. We Claim: 1. A process for preparation of alkylated dihydroxy benzene which comprises; alkylating dihydroxy benzene with tertiary butyl alcohol in presence of solid acid or polyaniline- sulfate catalyst in the temperature range from 40 to 90°C for a period of 2 to 8 hrs, separating the alkylated dihydroxy benzene by conventional method from the reacting mixture. 2. A process as claimed in claim 1, wherein the dihydroxy benzene used is selected from resorcinol, hydroquinone and catechol. 3. A process as claimed in claims 1-2, wherein the catalysts used is selected from zeolites of types HZSM-5 (SiO2/Al2O3 = 30), HY (SiO2 /A12O3 = 5.2), H-MORDENITE (HM) (SiO2/ A12O3 = 20), MCM-41, MONTMORINLLONITE-K10 CLAY, ALUMINA and polymer of type polynailine-sulfate. 4. A process as claimed in claims 1-3, wherein the reaction is carried out in the temperature from 60 to 90°C. 5. A process as claimed in claim 1-4, the reaction is carried out for a period of 6 to 8 hrs. 6. A process for preparation of alkylated dihydroxy benzene substantially as herein described with reference to the examples.

Documents:

1206-del-2000-abstract.pdf

1206-del-2000-claims.pdf

1206-del-2000-correspondence-others.pdf

1206-del-2000-correspondence-po.pdf

1206-del-2000-description (complete).pdf

1206-del-2000-form-1.pdf

1206-del-2000-form-19.pdf

1206-del-2000-form-2.pdf

1206-del-2000-form-3.pdf

1206-del-2000-petition-138.pdf