Title of Invention	"AN IMPROVED PROCESS FOR THE PREPARATION OF MIXTURE OF CATECHOL AND HYDROQUINONE FROM PHENOL"
Abstract	The present invention relates to process of preparation of catechol and mixture of catechol and hydroquinone from phenol. Moreover the invention is directed towards the selective process for the preparation of catechol and hydroquinone from phenol using TS-1 zeolite catalyst under microemulsion / micellar / biphasic medium with an advantage to be able to change the product catechol to hydroquinone of the said ratio 5:1 to 1.2:1 or to only catechol.

Title of Invention

"AN IMPROVED PROCESS FOR THE PREPARATION OF MIXTURE OF CATECHOL AND HYDROQUINONE FROM PHENOL"

Abstract

The present invention relates to process of preparation of catechol and mixture of catechol and hydroquinone from phenol. Moreover the invention is directed towards the selective process for the preparation of catechol and hydroquinone from phenol using TS-1 zeolite catalyst under microemulsion / micellar / biphasic medium with an advantage to be able to change the product catechol to hydroquinone of the said ratio 5:1 to 1.2:1 or to only catechol.

Full Text	This invention relates to an improved process for the preparation of mixture of catechol and hydroquinone from phenol. More particularly the invention relates to a selective process for the preparation of catechol and hydroquinone from phenol using TS-1 zeolite catalyst under microemulsion / micellar / biphasic medium with an advantage to be able to change the product catechol to hydroquinone ratio from say 5:1 to 1.2:1 or to only catechol. Both catechol and Hydroquinone are used as photographic chemicals, and as analytical reagents. The catechol derivatives have, pharmaceutical importance. Some of the derivatives such as carbofuran have insecticidal properties. World over, the market for photographic chemicals is expected to taperdown due to advent of electronic means for recording images, as a result, a process with higher selectivity for Catechol has a higher commercial value. Secondly the process with flexibility to vary product catechol to hydroquinone ratio as per demand in the same reactor technologically will have an edge over the prevailing practices. The present improved process for the production of Catechol and Hydroquinone from hydroxylation of Phenol using Hydrogen peroxide in the jv range (3-0-35%) using imcrocmtrhrcn / mrcettar medium biphasic medium( using suitable organic solvent) and zeolite type TS-1 catalyst in the temperature range 20-99° C. The operating molar ratios for Phenol to hydrogen peroxide are typically in the range 20:1 to 1:1 with hydrogen peroxide utilization from 100% to as low as 25% and product catechol: hydroquinone ratio in the range 5:1 to 1.2:1 and in some cases catechol selectivity is 100%. The following publication may be referred to: 1. M. Allian, A. Germain and F. Figueras, 'Acid Catalyzed Hydroxylation of Phenol by Hydrogen Peroxide', Science and Technology in Catalysis, 1994, p239-244 2. Gareth D. Rees and Brian H. Robinson, 'Microemulsions and Organogels: Properties and Novel Applications', Adv. Mater. 1993, 5(9), P608-619 3. Reinhard Schomaker, 'Microemulsion in Technical Processes', Chem. Rev. 1995, 95, p849-864 4, N.M. Van Os, J.R. llaak and L.A.M. Rupert, ^'hysico-C Properties of Selected Anionic, Cationic and Nonionic Surfactants', Elsevier Science Publishers B.V., Amsterdam, The Netherlands, 1993 Many processes are known in the prior art for the conversion of Phenol to hydroquinone and catechol using hydrogen peroxide, H2O2 as the oxidant. In U.S. Pat. No. 3,929,913, assigned to Brichima( Now Enichem), the catalyst used is ferrocane, ferrous sulfate chelates are used as catalyst in U.S. Pat. No. 3,920,756. In another U.S. Pat. No. 3,914,324 by Brichima, the catalyst used is a mixture of trifluroacetic acid and monocarboxylic acid. In another U.S. Pat. No. 3,914,323 by Brichima, the catalyst used is essentially Cobalt salt in a quantity less than 1% molar with respect to the phenol and at a pH of less than 5. Brichima SpA in Italy uses heavy metal compounds ( e.g., small quantities of ferrocene and / or Cobalt salt) as catalyst and react phenol with 60% aqueous hydrogen peroxide at 40°C producing catechol and hydroquinone in the ratio of 1.5:4.1 as described by P. Maggioni, F. Minisci, Chim. Ind. (Milan) 59 (1977) 239-242. The reaction goes via free radical mechanism and is very fast. In prior art processes using titanium silicate molecular sieves, as for example, the Enichem Process, phenol and H202 in a molar ratio equal to or lower than 5, are contacted at 60"-150"C with a titanium silicate molecular sieve containing titanium in a proportion, calculated as Ti02, of between 0.1 and 7% by weight and preferably between 2 and 4% by weight to yield the products hydroquinone and catechol. In addition to the above desired products, significant amounts of heavy oxidation products, hereinafter referred as tar, were also produced in the process. In example 5 of U.S. Pat. No. 4,396,783, for instance, 21% by weight of phenol was converted into by product tar. The tar originates from the further reaction of hydroquinone and catechol at the elevated temperatures during the exothermic oxidation of phenol. Any modification of the process which reduces the formation of tar will constitute a significant improvement of the process. In the Rhone Poulenc process described by J. Varagnat in the journal of Industrial Engg. Chemistry Product Research Development, vol 15, page 212 (1976), a combination of phosphoric acid and perchloric acids are used as catalysts. The process describes use of 70% Hydrogen peroxide ( molar ratio 20:1) in the presence of phosphoric acid and catalytic amounts of perchloric acid at 90° C; catechol and hydroquinone are obtained in a ratio of ca. 3:2. The U.S. Pat No. 4,223,165 and U.S. Pat. 4,301,307 by Rhone Poulenc Industries, describe the hydroxylation of phenol using trifluromethanesulfonic acid reporting high yields of hydroxylated aromatic compounds. The patent describes that the process avoids use of extremely corrosive and difficult to handle reagents. Phenol is predominantly hydroxylated to hydroquinone by this process. The use of molecular sieves as catalysts for the oxidation of phenol to hydroquinone and catechol using H2O2 as oxidant is also known. European Patent 0266825 describes the use of crystalline gallium titanium silicate as catalysts. European Patent 0265018 describes the use, as catalyst, of zeolites with a pore diameter between 5 and 12 Angstroms. Of more relevance to the present invention, U.S. Pat. No. 4,396,783 and U.K. Patent 2,116,974 both assigned to Enichem claim the use of a titanium silicate molecular sieve, TS-1, in the hydroxylation of aromatics. In Japan, Ube Industries produce catechol together with hydroquinone by hydroxylation of phenol with ketone peroxides formed in situ from a ketone and hydrogen peroxide in the presence of an acid catalyst as described in U.S. Pat. 4,078,006 and publication by T. Hamamoto, N. Kuroda, N. Takamitu, S. Umemura, Nippon Kagaku Kaishi 1980, 1850-1854. The process is carried out by adding a trace amount of acid ( e.g., sulfuric or sulfonic acid ), a small volume of ketone, and 60% aqueous hydrogen peroxide to phenol at 70° C. The ketone peroxide that is formed in situ reacts rapidly and electrophilically with phenol, and catechol and hydroquinone are obtained in a molar ratio of about 3:2 in more than 90% yield (based on phenol reacted). When a solid acid such as clay is used as catalyst, the molar ratio of catechol and hydroquinone is about 1:1 as described in JP-Kokai 52 118436, assigned to Ube Industries . As only a small amount of catalyst is used, no corrosion occurs and the reaction mixture can be distilled without removing the catalyst after the reaction. The added ketone can be recycled to the process by recovering it by distillation. The U.S. Patent 5,493,061 from CSIR by Ratnasamy et. al describes an improved process for the conversion of Phenol to Hydroquinone and Catechol in a multistage fixed bed reactor using Titanium Silicate molecular sieves. The operating temperature is below 65°C, however this process gives the products only in fixed ratios and the same could not be changed as desired. The earlier processes suffer from a drawback such as inability to control the products, i.e. Catechol Hydroquinone ratio. The catalyst used such as perchloric acid is highly corrosive in nature. It is therefore desirable to have a process for the preparation of hydroquinone and catechol wherein it is possible to obtain the products in the desired ratios and as per the industrial need. The main object of the present invention is to provide an improved process for hydroquinone and catechol wherein the products could be obtained as in the desired ratios, as per market demand without changing reactor and catalyst, TS-1. Another object of the present invention is to provide a process wherein the use of hazardous chemicals is eliminated thereby providing an echo friendly Accordingly, the present invention provides An improved process for the preparation of mixture of catechol and hydroquinone from phenol, which comprises contacting a mixture of solution of phenol in a solvent, a surfactant and optionally in the presence of a co-surfactant over the catalyst such as herein described, adding to this mixture hydrogen peroxide and the ratio of phenol to hydrogen peroxide being in the ratio of 20:1 to 1:1, maintaining the reaction mixture at a temperature ranging from 40-55°C for 15 minutes to 4 hrs to obtain a mixture of catechol and hydroquinone, removing the catalyst by conventional methods characterized in that the product obtained is a mixture of catechol and hydroquinone in a ratio of 5:1 to 1.2:1 with high selectivity. In .an embodiment of the present invention the solvent used for preparing solution of phenol may be selected from water, Methyl ethyl ketone. Acetone, Ethyl acetate, carbon tetrachloride, Cyclohexanone, Diethyl ether, preferably water, Methyl ethyl ketone. In an embodiment of the present invention the Phenol to Hydrogen peroxide mole ratio may range from 20:1 to 1:1. In the embodiment of the present invention, the surfactant used may be SDS (Sodium dodecyl sulfate ), SDBS (Dodecyl Benzene sulfomc acid Sodium salt ), CTAB (Cetyltrimethylammoniurn bromide ), TX-100 ( Triton X-100 ), preferably SDS. In the embodiment of the present invention, the Co-surfactant may be n-Butanol, n-Pentanol, n-Hexanol, n-Heptanol, n-Octanol, n-Nonanol, n-Decanol, preferably n-Heptanol. In yet another embodiment the surfactant concentration may range from 0.5 times CMC ( critical micelle concentration) value to 100 times CMC at operating temperature. In the embodiment of the present invention, the catalyst used may be a Titanium Silicate molecular sieve, a zeolite such as TS-1. In a feature of the present invention the ratio of the products formed may be controlled by use of appropriate combination of surfactant in presence or absence of co-surfactants. In another feature of the invention the process could be carried out on a fixed bed reactor or in a continuous stirred tank reactor. The process of the present invention is described by following examples, which are illustrative only and should not be considered to limit the scope of the present invention. Example-l 5.51404 grams of Phenol (99%) is dissolved in 25 grams of distilled water to this 0.08089 grams of SDS was added and the mixture is stirred. 4.00388 grams of TS-1 catalyst are added to the above solution and then 1.1531 grams of 35% Hydrogen peroxide is added. The above mixture is stirred magnetically in a jacketed reactor maintained at 58° C. The reaction is carried out at 58° C under stirring to produce product catechol only or mixture of catechol and hydroquinone in the ratio 1.53:1. The product sample is withdrawn from this bath reactor at specific intervals and analyzed. The typical yields is given in Table 1 Table-1 Phenol and Hydrogen peroxide conversion and Product distribution Data (Table Removed) ExampIe-2 8.691166 grams of Phenol (99%) is dissolved in 5.00486 grams of distilled water to this 0.04914 grams of SDS was added and the mixture is stirred. 6.4547 grams of TS-1 catalyst are added to the above solution and then 4.92187 grams of 35% Hydrogen peroxide is added. The above mixture is stirred magnetically in a jacketed reactor maintained at 58° C. The reaction is carried out at 58° C under stirring to produce product catechol and hydroquinone in the ratio approximately 2.52:1. The result indicates a 49.42% of hydrogen peroxide conversion in an hour. ExampIe-3 1.11472 grams of Phenol (99%) is dissolved in 10.0 grams of distilled water to this 0.01389 grams of SDS was added and the mixture is stirred. 0.80552 grams of TS-1 catalyst are added to the above solution and then 0.265 grams of 30% Hydrogen peroxide is added. The above mixture is stirred magnetically in a jacketed reactor maintained at 40° C. The reaction is carried out at 40° C under stirring to produce product catechol and hydroquinone in the ratio approximately 5.1:1. The result indicates a 59.9 % of hydrogen peroxide conversion in an hour. Example-4 1.739 grams of Phenol (99%) is dissolved in 3.01309 grams of Methyl Ethyl Ketone (distilled) to this 0.00634 grams of SDS was added and the mixture is stirred. 1.07826 grams of TS-1 catalyst are added to the above solution and then 1.50688 grams of 35% Hydrogen peroxide is added. The above mixture is stirred magnetically in a jacketed reactor maintained at 58° C. The reaction is carried out at 58° C under stirring to produce product catechol and hydroquinone in the ratio approximately 3.75:1. The result indicates a 21.56% of hydrogen peroxide conversion in half an hour with a maximum of 41.28% conversion in 4 hours. ExampIe-5 13.03776 grams of Phenol (99%) is dissolved in 7.50713 grams of distilled water to this 0.07508 grams of SDS was added and the mixture is stirred. 7.0923 grams of Methyl Ethyl Ketone is added and to the above solution and then 9.68280 grams of TS-1 catalyst is added to the above solution and then 7.3883 grams of 35% Hydrogen peroxide is added. The above mixture is stirred magnetically in a jacketed reactor maintained at 58° C. The reaction is carried out at 58° C under stirring to produce product catechol and hydroquinone in the ratio approximately 3.37:1. The result indicates a 34.86% of hydrogen peroxide conversion in half an hour with a maximum of 50.75% in 4 hours. Example-6 1.12012 grams of Phenol (99%) is dissolved in 10.02035 grams of distilled water to this 0.0249 grams of CTABS was added and the mixture is stirred and then 0.85 grams of TS-1 catalyst is added to the above solution and then 0.265 grams of 30% Hydrogen peroxide is added. The above mixture is kept in a thermostat maintained at 40° C. The reaction is carried out at 40° C under no stirring conditions to produce selectively catechol. The result indicates a 39.87% of hydrogen peroxide conversion in an hour. The main advantages of the present invention are as follows: 1. The process can be used to obtain the products in the desired ratios. 2. The use of hazardous chemicals is eliminated. 3. The process can be used for the production of the products in a continuous or batch mode. We Claim: 1. An improved process for the preparation of mixture of catechol and hydroquinone from phenol, which comprises contacting a mixture of solution of phenol in a solvent, a surfactant and optionally in the presence of a co-surfactant over the catalyst such as herein described, adding to this mixture hydrogen peroxide and the ratio of phenol to hydrogen peroxide being in the ratio of 20:1 to 1:1, maintaining the reaction mixture at a temperature ranging from 40- 55°C for 15 minutes to 4 hrs to obtain a mixture of catechol and hydroquinone, removing the catalyst by conventional methods characterized in that the product obtained is a mixture of catechol and hydroquinone in a ratio of 5:1 to 1.2:1 with high selectivity. 2. A process as claimed in claim 1, wherein the solvent used for preparing solution of phenol is selected from water, methyl ethyl ketone, acetone, ethyl acetate, carbon tetrachloride, cyclohexanone, diethyl ether, preferably water, methyl ethyl ketone. 3. A process as claimed in claim 1, wherein the surfactant used is SDS [Sodium Dodecyl Sulfate], SDBS [Dodecyl Benzene sulfonic acid Sodium salt], CTAB [Cetyltrimethylammonium bromide], TX-100 [Triton X-100] preferably SDS. 4. A process as claimed in claim 1, wherein the co-surfactant used is such as n-butanol, n- pentanol, n-hexanol, n-heptanol, n-octanol, n-nonanol, n-decanol, preferably n-heptanol. 5. A process as claimed in claim 1, wherein the surfactant concentration ranges from 0.5 times CMC [critical micelle concentration] value to 100 times CMC. 6. An improved process for the preparation of mixture of catechol and hydroquinone from phenol substantially as herein described with reference to the foregoing examples.

Full Text

This invention relates to an improved process for the preparation of mixture of catechol and hydroquinone from phenol. More particularly the invention relates to a selective process for the preparation of catechol and hydroquinone from phenol using TS-1 zeolite catalyst under microemulsion / micellar / biphasic medium with an advantage to be able to change the product catechol to hydroquinone ratio from say 5:1 to 1.2:1 or to only catechol.
Both catechol and Hydroquinone are used as photographic chemicals, and as analytical reagents. The catechol derivatives have, pharmaceutical importance. Some of the derivatives such as carbofuran have insecticidal properties.
World over, the market for photographic chemicals is expected to taperdown due to advent of electronic means for recording images, as a result, a process with higher selectivity for Catechol has a higher commercial value. Secondly the process with flexibility to vary product catechol to hydroquinone ratio as per demand in the same reactor technologically will have an edge over the prevailing practices.
The present improved process for the production of Catechol and Hydroquinone from hydroxylation of Phenol using Hydrogen peroxide in the jv range (3-0-35%) using imcrocmtrhrcn / mrcettar medium

biphasic medium( using suitable organic solvent) and zeolite type TS-1 catalyst in the temperature range 20-99° C. The operating molar ratios for Phenol to hydrogen peroxide are typically in the range 20:1 to 1:1 with hydrogen peroxide utilization from 100% to as low as 25% and product catechol: hydroquinone ratio in the range 5:1 to 1.2:1 and in some cases catechol selectivity is 100%.
The following publication may be referred to:
1. M. Allian, A. Germain and F. Figueras, 'Acid Catalyzed
Hydroxylation of Phenol by Hydrogen Peroxide', Science and
Technology in Catalysis, 1994, p239-244
2. Gareth D. Rees and Brian H. Robinson, 'Microemulsions and
Organogels: Properties and Novel Applications', Adv. Mater. 1993,
5(9), P608-619
3. Reinhard Schomaker, 'Microemulsion in Technical Processes', Chem.
Rev. 1995, 95, p849-864
4, N.M. Van Os, J.R. llaak and L.A.M. Rupert, ^'hysico-C
Properties of Selected Anionic, Cationic and Nonionic Surfactants', Elsevier Science Publishers B.V., Amsterdam, The

Netherlands, 1993
Many processes are known in the prior art for the conversion of Phenol to hydroquinone and catechol using hydrogen peroxide, H2O2 as the oxidant. In U.S. Pat. No. 3,929,913, assigned to Brichima( Now Enichem), the catalyst used is ferrocane, ferrous sulfate chelates are used as catalyst in U.S. Pat. No. 3,920,756. In another U.S. Pat. No. 3,914,324 by Brichima, the catalyst used is a mixture of trifluroacetic acid and monocarboxylic acid. In another U.S. Pat. No. 3,914,323 by Brichima, the catalyst used is essentially Cobalt salt in a quantity less than 1% molar with respect to the phenol and at a pH of less than 5. Brichima SpA in Italy uses heavy metal compounds ( e.g., small quantities of ferrocene and / or Cobalt salt) as catalyst and react phenol with 60% aqueous hydrogen peroxide at 40°C producing catechol and hydroquinone in the ratio of 1.5:4.1 as described by P. Maggioni, F. Minisci, Chim. Ind. (Milan) 59 (1977) 239-242.
The reaction goes via free radical mechanism and is very fast.
In prior art processes using titanium silicate molecular sieves, as for example, the Enichem Process, phenol and H202 in a molar ratio equal to or lower than 5, are contacted at 60"-150"C with a titanium silicate molecular sieve containing titanium in a proportion, calculated as Ti02, of between 0.1 and 7% by weight and preferably between 2 and 4% by weight to yield the

products hydroquinone and catechol. In addition to the above desired products, significant amounts of heavy oxidation products, hereinafter referred as tar, were also produced in the process. In example 5 of U.S. Pat. No. 4,396,783, for instance, 21% by weight of phenol was converted into by product tar. The tar originates from the further reaction of hydroquinone and catechol at the elevated temperatures during the exothermic oxidation of phenol. Any modification of the process which reduces the formation of tar will constitute a significant improvement of the process.
In the Rhone Poulenc process described by J. Varagnat in the journal of Industrial Engg. Chemistry Product Research Development, vol 15, page 212 (1976), a combination of phosphoric acid and perchloric acids are used as catalysts. The process describes use of 70% Hydrogen peroxide ( molar ratio 20:1) in the presence of phosphoric acid and catalytic amounts of perchloric acid at 90° C; catechol and hydroquinone are obtained in a ratio of ca. 3:2. The U.S. Pat No. 4,223,165 and U.S. Pat. 4,301,307 by Rhone Poulenc Industries, describe the hydroxylation of phenol using trifluromethanesulfonic acid reporting high yields of hydroxylated aromatic compounds. The patent describes that the process avoids use of extremely corrosive and difficult to handle reagents. Phenol is predominantly hydroxylated to hydroquinone by this process.
The use of molecular sieves as catalysts for the oxidation of phenol to

hydroquinone and catechol using H2O2 as oxidant is also known. European Patent 0266825 describes the use of crystalline gallium titanium silicate as catalysts. European Patent 0265018 describes the use, as catalyst, of zeolites with a pore diameter between 5 and 12 Angstroms. Of more relevance to the present invention, U.S. Pat. No. 4,396,783 and U.K. Patent 2,116,974 both assigned to Enichem claim the use of a titanium silicate molecular sieve, TS-1, in the hydroxylation of aromatics.
In Japan, Ube Industries produce catechol together with hydroquinone by hydroxylation of phenol with ketone peroxides formed in situ from a ketone and hydrogen peroxide in the presence of an acid catalyst as described in U.S. Pat. 4,078,006 and publication by T. Hamamoto, N. Kuroda, N. Takamitu, S. Umemura, Nippon Kagaku Kaishi 1980, 1850-1854. The process is carried out by adding a trace amount of acid ( e.g., sulfuric or sulfonic acid ), a small volume of ketone, and 60% aqueous hydrogen peroxide to phenol at 70° C. The ketone peroxide that is formed in situ reacts rapidly and electrophilically with phenol, and catechol and hydroquinone are obtained in a molar ratio of about 3:2 in more than 90% yield (based on phenol reacted). When a solid acid such as clay is used as catalyst, the molar ratio of catechol and hydroquinone is about 1:1 as described in JP-Kokai 52 118436, assigned to Ube Industries . As only a small amount of catalyst is used, no corrosion occurs and the reaction mixture can be distilled without removing the catalyst after the reaction. The added ketone can be recycled to the

process by recovering it by distillation.
The U.S. Patent 5,493,061 from CSIR by Ratnasamy et. al describes an improved process for the conversion of Phenol to Hydroquinone and Catechol in a multistage fixed bed reactor using Titanium Silicate molecular sieves. The operating temperature is below 65°C, however this process gives the products only in fixed ratios and the same could not be changed as desired.
The earlier processes suffer from a drawback such as inability to control the products, i.e. Catechol Hydroquinone ratio. The catalyst used such as perchloric acid is highly corrosive in nature.
It is therefore desirable to have a process for the preparation of hydroquinone and catechol wherein it is possible to obtain the products in the desired ratios and as per the industrial need.
The main object of the present invention is to provide an improved process for hydroquinone and catechol wherein the products could be obtained as in the desired ratios, as per market demand without changing reactor and catalyst, TS-1.
Another object of the present invention is to provide a process wherein the use of hazardous chemicals is eliminated thereby providing an echo friendly

Accordingly, the present invention provides An improved process for the preparation of mixture of catechol and hydroquinone from phenol, which comprises contacting a mixture of solution of phenol in a solvent, a surfactant and optionally in the presence of a co-surfactant over the catalyst such as herein described, adding to this mixture hydrogen peroxide and the ratio of phenol to hydrogen peroxide being in the ratio of 20:1 to 1:1, maintaining the reaction mixture at a temperature ranging from 40-55°C for 15 minutes to 4 hrs to obtain a mixture of catechol and hydroquinone, removing the catalyst by conventional methods characterized in that the product obtained is a mixture of catechol and hydroquinone in a ratio of 5:1 to 1.2:1 with high selectivity.
In .an embodiment of the present invention the solvent used for preparing
solution of phenol may be selected from water, Methyl ethyl ketone.
Acetone, Ethyl acetate, carbon tetrachloride, Cyclohexanone, Diethyl ether, preferably water, Methyl ethyl ketone.
In an embodiment of the present invention the Phenol to Hydrogen peroxide mole ratio may range from 20:1 to 1:1.
In the embodiment of the present invention, the surfactant used may be SDS (Sodium dodecyl sulfate ), SDBS (Dodecyl Benzene sulfomc acid Sodium salt ), CTAB (Cetyltrimethylammoniurn bromide ), TX-100 ( Triton X-100 ), preferably SDS.

In the embodiment of the present invention, the Co-surfactant may be n-Butanol, n-Pentanol, n-Hexanol, n-Heptanol, n-Octanol, n-Nonanol, n-Decanol, preferably n-Heptanol.
In yet another embodiment the surfactant concentration may range from 0.5 times CMC ( critical micelle concentration) value to 100 times CMC at operating temperature.
In the embodiment of the present invention, the catalyst used may be a Titanium Silicate molecular sieve, a zeolite such as TS-1.
In a feature of the present invention the ratio of the products formed may be controlled by use of appropriate combination of surfactant in presence or absence of co-surfactants.
In another feature of the invention the process could be carried out on a fixed bed reactor or in a continuous stirred tank reactor.
The process of the present invention is described by following examples, which are illustrative only and should not be considered to limit the scope of the present invention.

Example-l
5.51404 grams of Phenol (99%) is dissolved in 25 grams of distilled water to this 0.08089 grams of SDS was added and the mixture is stirred. 4.00388 grams of TS-1 catalyst are added to the above solution and then 1.1531 grams of 35% Hydrogen peroxide is added. The above mixture is stirred magnetically in a jacketed reactor maintained at 58° C.
The reaction is carried out at 58° C under stirring to produce product catechol only or mixture of catechol and hydroquinone in the ratio 1.53:1. The product sample is withdrawn from this bath reactor at specific intervals and analyzed. The typical yields is given in Table 1
Table-1 Phenol and Hydrogen peroxide conversion and Product distribution
Data
(Table Removed)

ExampIe-2
8.691166 grams of Phenol (99%) is dissolved in 5.00486 grams of distilled water to this 0.04914 grams of SDS was added and the mixture is stirred.

6.4547 grams of TS-1 catalyst are added to the above solution and then 4.92187 grams of 35% Hydrogen peroxide is added. The above mixture is stirred magnetically in a jacketed reactor maintained at 58° C.
The reaction is carried out at 58° C under stirring to produce product catechol and hydroquinone in the ratio approximately 2.52:1. The result indicates a 49.42% of hydrogen peroxide conversion in an hour.
ExampIe-3
1.11472 grams of Phenol (99%) is dissolved in 10.0 grams of distilled water to this 0.01389 grams of SDS was added and the mixture is stirred. 0.80552 grams of TS-1 catalyst are added to the above solution and then 0.265 grams of 30% Hydrogen peroxide is added. The above mixture is stirred magnetically in a jacketed reactor maintained at 40° C.
The reaction is carried out at 40° C under stirring to produce product catechol and hydroquinone in the ratio approximately 5.1:1. The result indicates a 59.9 % of hydrogen peroxide conversion in an hour.
Example-4
1.739 grams of Phenol (99%) is dissolved in 3.01309 grams of Methyl

Ethyl Ketone (distilled) to this 0.00634 grams of SDS was added and the mixture is stirred. 1.07826 grams of TS-1 catalyst are added to the above solution and then 1.50688 grams of 35% Hydrogen peroxide is added. The above mixture is stirred magnetically in a jacketed reactor maintained at 58° C. The reaction is carried out at 58° C under stirring to produce product catechol and hydroquinone in the ratio approximately 3.75:1. The result indicates a 21.56% of hydrogen peroxide conversion in half an hour with a maximum of 41.28% conversion in 4 hours.
ExampIe-5
13.03776 grams of Phenol (99%) is dissolved in 7.50713 grams of distilled water to this 0.07508 grams of SDS was added and the mixture is stirred. 7.0923 grams of Methyl Ethyl Ketone is added and to the above solution and then 9.68280 grams of TS-1 catalyst is added to the above solution and then 7.3883 grams of 35% Hydrogen peroxide is added. The above mixture is stirred magnetically in a jacketed reactor maintained at 58° C.
The reaction is carried out at 58° C under stirring to produce product catechol and hydroquinone in the ratio approximately 3.37:1. The result indicates a 34.86% of hydrogen peroxide conversion in half an hour with a maximum of 50.75% in 4 hours.

Example-6
1.12012 grams of Phenol (99%) is dissolved in 10.02035 grams of distilled water to this 0.0249 grams of CTABS was added and the mixture is stirred and then 0.85 grams of TS-1 catalyst is added to the above solution and then 0.265 grams of 30% Hydrogen peroxide is added. The above mixture is kept in a thermostat maintained at 40° C.
The reaction is carried out at 40° C under no stirring conditions to produce selectively catechol. The result indicates a 39.87% of hydrogen peroxide conversion in an hour.
The main advantages of the present invention are as follows:
1. The process can be used to obtain the products in the desired ratios.
2. The use of hazardous chemicals is eliminated.
3. The process can be used for the production of the products in a
continuous or batch mode.

We Claim:
1. An improved process for the preparation of mixture of catechol and hydroquinone from
phenol, which comprises contacting a mixture of solution of phenol in a solvent, a surfactant
and optionally in the presence of a co-surfactant over the catalyst such as herein described,
adding to this mixture hydrogen peroxide and the ratio of phenol to hydrogen peroxide being
in the ratio of 20:1 to 1:1, maintaining the reaction mixture at a temperature ranging from 40-
55°C for 15 minutes to 4 hrs to obtain a mixture of catechol and hydroquinone, removing the
catalyst by conventional methods characterized in that the product obtained is a mixture of
catechol and hydroquinone in a ratio of 5:1 to 1.2:1 with high selectivity.
2. A process as claimed in claim 1, wherein the solvent used for preparing solution of phenol is
selected from water, methyl ethyl ketone, acetone, ethyl acetate, carbon tetrachloride,
cyclohexanone, diethyl ether, preferably water, methyl ethyl ketone.
3. A process as claimed in claim 1, wherein the surfactant used is SDS [Sodium Dodecyl
Sulfate], SDBS [Dodecyl Benzene sulfonic acid Sodium salt], CTAB
[Cetyltrimethylammonium bromide], TX-100 [Triton X-100] preferably SDS.
4. A process as claimed in claim 1, wherein the co-surfactant used is such as n-butanol, n-
pentanol, n-hexanol, n-heptanol, n-octanol, n-nonanol, n-decanol, preferably n-heptanol.
5. A process as claimed in claim 1, wherein the surfactant concentration ranges from 0.5 times
CMC [critical micelle concentration] value to 100 times CMC.
6. An improved process for the preparation of mixture of catechol and hydroquinone from
phenol substantially as herein described with reference to the foregoing examples.

Documents:

1682-del-1998-abstract.pdf

1682-del-1998-claims.pdf

1682-del-1998-correspondence-others.pdf

1682-del-1998-correspondence-po.pdf

1682-del-1998-description (complete).pdf

1682-del-1998-form-1.pdf

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1682-del-1998-form-2.pdf

1682-del-1998-form-3.pdf

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Patent Number

215670

Indian Patent Application Number

1682/DEL/1998

PG Journal Number

12/2008

Publication Date

21-Mar-2008

Grant Date

29-Feb-2008

Date of Filing

18-Jun-1998

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	NIRMAL KISHOR YADAV	NATIONAL CHEMICAL LABORATORY, PUNE, MAHARASHTRA, INDIA.
2	BHASKAR DATTATRAYA KULKARNI	NATIONAL CHEMICAL LABORATORY, PUNE, MAHARASHTRA, INDIA.
3	RAMDAS BHAGVAN KHOMANE	NATIONAL CHEMICAL LABORATORY, PUNE, MAHARASHTRA, INDIA.

PCT International Classification Number

C07D 215/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA