Title of Invention	A PROCESS FOR THE HOMOGENEOUS OXIDATION OF ALKYL BENZENE CATALYZED BY HETEROPOLY COMPOUNDS
Abstract	Aprocess for the homogteneous oxidation of alkyl benzene catalyzed by heteropoly compounds comprises the steps of carrying out the homogeneous oxidation of the said alkyl benzene in a solvent selected from (i) acetonitrile (ii) actetiv acit,in the presence of a heteropolymolybdate as catalyst.The temperature range is 303-335 k.The oxidizing agent is selected from (i) hydrogen peroxide (ii) tertbutlyi hydro9peroxide.The resuloting products are extracted into dichloromethane and the catalyst is removed by washing with water.

Title of Invention

A PROCESS FOR THE HOMOGENEOUS OXIDATION OF ALKYL BENZENE CATALYZED BY HETEROPOLY COMPOUNDS

Abstract

Aprocess for the homogteneous oxidation of alkyl benzene catalyzed by heteropoly compounds comprises the steps of carrying out the homogeneous oxidation of the said alkyl benzene in a solvent selected from (i) acetonitrile (ii) actetiv acit,in the presence of a heteropolymolybdate as catalyst.The temperature range is 303-335 k.The oxidizing agent is selected from (i) hydrogen peroxide (ii) tertbutlyi hydro9peroxide.The resuloting products are extracted into dichloromethane and the catalyst is removed by washing with water.

Full Text	This ' invention relates to a process for a homogenous oxidation of alkyl benzenes catalyzed by heteropoly compounds. A description of the prior art: Aromatic hydrocarbons constitute one of the major groups of basic building blocks of the petrochemical industry. The important source is the catalytic reforming of naphtha which affords a mixture of benzene, toluene, ethylbenzene and xylenes together with C9 and C10 aromatic hydrocarbons, Oxidation is the widely used process in the conversion of aromatic hydrocarbons to industrial chemicals like phenol, terephthalic acid and acetone. The traditional reagents used for the conversion of methylbenzenes to the corresponding benzoic acid on the laboratory scale are potassium permanganate or chromyl compounds employed in stoichiometric amounts. The industrial scale oxidations of this type were generally carried out with stoichiometric amounts of nitric acid until the last decade. Transition metal catalyzed reactions of oxygen donors with aromatics afforded high selectivities of products derived from side chain oxidation and nuclear hydroxylation of aromatics. The oxidation of phenol to the dihydroxy benzene products, catechol and hydroquinone are of major interest and there are three major hydrogen peroxide processes currently in use (Brown et al 1992). Transition metal substituted silicalites like TS-1 and VS-2 were used as catalyst for this particular conversion (Hari prasad Rao and Ramaswamy 1993; Allian et al 1994) and vanadium substituted heteropoly molybdate and tungstate were used for the hydroxylation of phenol (Brown et al 1992). Heteropoly compounds were also used as catalysts for the conversion of phenols in the presence of molecular oxygen (Shimiyu et al 1990; Kholdeeva et al 1992Lissel et al 1992; Fujibashi et al 1994). The improvements made by the invention and the advantages The improvements and advantages of the process claimed are (i) the reaction can be carried out in homogeneous medium (ii) the reaction can be carried out around room temperature (iii) A variety of solvents like acetonitrile acetic acid and mixture of acetonitrile and water also can be used as solvents. (iv) The vanadium content in the heteropoly molybdate can be varied upto 3 vanadium atoms per heteropoly unit and the activity in terms of conversion increases with increase in vanadium content, (v) A variety of aromatic substrates namely toluene, ethyl benzene, p-xylene, isopropyl benzene chlorobenzene 1,3,5 and 1,2,4 trimethyl benzene, poly aromatics like naphthalene and biphenyl and organic sulphides like methyl sulphide, n-propyl sulphide and phenyl sulphide could oxidized yielding both side chain and ring oxidized products. (vi) A variety of oxidizing agents like hydrogen peroxide and tert-butyl hydroperoxide can be used for oxidation. The uses to which the products obtained can be put (i) The ring hydroxylated products and the side chain products are starting materials for many organic reactions and synthesis. (ii) Some of the products like phenols can be used in the production of pharmaceuticals and other fine chemicals. (iii) Some of the chemicals can be used as organic solvents The novel features of the invention when compared to the prior art A typical comparison data for the oxidation of toluene with hydrogen peroxide by three catalysts in acetonitrile is given in the Table given below • Ramaswamy and Sivasankar 1993 • *Sussaine et al 1983 V-NCL-1 the side chain oxidized product was the predominant one whereas the behaviour of vanadium heteropolymolybdat&resembled that of the vanadiumperoxo complex. But the reaction is homogeneous phase in vanadium complex and the preparation of the complex is comparatively more involved than the preparation of heteropolyvanadomolybdate. Homogeneous oxidation of alkyl benzenes was carried out in the temperature range 303-335 K for three hours with acetonitrile as solvent. Hydrogen peroxide substrate ratio of 2.5 or tert-butyl hydroperoxide versus substrate ratio of nearly 1 was used in these experiments. After the experiment the products were extracted into dichloromethane and the catalyst was removed by washing with water. The products were analyzed both by GC-MS and GC alone. The various catalysts were prepared by adopting suitable procedures for example H3PV2M010O40 and H3PV3M09O40 were prepared as red and deep red crystals by the stoichiometric addition of the oxides followed by acidification and esterification. Similarly special procedures were adopted for the synthesis other heteropoly compounds like H3PMo6W6O40, H4PVMo6W5O40, H5PV2W10O40 and K7Ti2W10P04o. EXAMPLE Typical data for the conversion of toluene with variation of vanadium content in heteropoly compounds, the effect of temperature and the variation of alkylbenzenes used are given in the following Tables 1-3 We Claims 1. A process for the homogeneous oxidation of alkyl benzenes catalyzed by heteropoly compounds for obtaining ring hydroxylated products and side chain products, comprising the steps of carrying out the homogeneous oxidation of the said alkyl benzene in a solvent selected from (i) acetonitrile (ii) acetic acid in the presence of a heteropolymolybdate as catalyst, in a temperature range of 303 - 33S K, the oxidizing agent being selected from (i) hydrogen peroxide (i i) tert-butyl hydroperoxide; extracting the resulting products into dichloromethane; and removing the catalyst by washing with water. 2. A process as claimed in Claim 1 wherein the oxidation is carried'out for three hours. 3. A process as claimed in Claim 1 or Claim 2 WHEREIN the hydrogen peroxide to substrate ratio is 2.5 4. A process as claimed in Claim i or Claim 2 wherein the tert-butyl hydroperoxide to substrate ratio is nearly 1. 5. A process as claimed in any one of the preceding Claims wherein the catalyst used is a Vanadium-substituted heteropolymolybdate- 6. A process for the homogeneous oxidation of alkyl benzenes catalysed by heteropoly' compounds to obtain fing hydroxylated products and side chain products, substantially as herein described and illustrated by the Example. 7. Ring hydroxylated products and side chain products, whenever prepared by a process as claimed in any one of the preceding Claims.

Full Text

This ' invention relates to a process for a homogenous
oxidation of alkyl benzenes catalyzed by heteropoly compounds.
A description of the prior art:
Aromatic hydrocarbons constitute one of the major groups of basic building blocks of the petrochemical industry. The important source is the catalytic reforming of naphtha which affords a mixture of benzene, toluene, ethylbenzene and xylenes together with C9 and C10 aromatic hydrocarbons, Oxidation is the widely used process in the conversion of aromatic hydrocarbons to industrial chemicals like phenol, terephthalic acid and acetone. The traditional reagents used for the conversion of methylbenzenes to the corresponding benzoic acid on the laboratory scale are potassium permanganate or chromyl compounds employed in stoichiometric amounts. The industrial scale oxidations of this type were generally carried out with stoichiometric amounts of nitric acid until the last decade. Transition metal catalyzed reactions of oxygen donors with aromatics afforded high selectivities of products derived from side chain oxidation and nuclear hydroxylation of aromatics. The oxidation of phenol to the dihydroxy benzene products, catechol and hydroquinone are of major interest and there are three major hydrogen peroxide processes currently in use (Brown et al 1992). Transition metal substituted silicalites like TS-1 and VS-2 were used as catalyst for this particular conversion (Hari prasad Rao and Ramaswamy 1993; Allian et al 1994) and vanadium substituted heteropoly molybdate and tungstate were used for the hydroxylation of phenol (Brown et al 1992). Heteropoly compounds were also used as catalysts for the conversion of phenols in the presence of molecular oxygen (Shimiyu et al 1990; Kholdeeva et al 1992Lissel et al 1992; Fujibashi et al 1994).
The improvements made by the invention and the advantages
The improvements and advantages of the process claimed are
(i) the reaction can be carried out in homogeneous medium
(ii) the reaction can be carried out around room temperature
(iii) A variety of solvents like acetonitrile acetic acid and mixture of
acetonitrile and water also can be used as solvents. (iv) The vanadium content in the heteropoly molybdate can be varied upto 3 vanadium atoms per heteropoly unit and the activity in terms of conversion increases with increase in vanadium content, (v) A variety of aromatic substrates namely toluene, ethyl benzene, p-xylene, isopropyl benzene chlorobenzene 1,3,5 and 1,2,4 trimethyl benzene, poly aromatics like naphthalene and biphenyl and organic

sulphides like methyl sulphide, n-propyl sulphide and phenyl sulphide could oxidized yielding both side chain and ring oxidized products. (vi) A variety of oxidizing agents like hydrogen peroxide and tert-butyl hydroperoxide can be used for oxidation.
The uses to which the products obtained can be put
(i) The ring hydroxylated products and the side chain products are starting materials for many organic reactions and synthesis.
(ii) Some of the products like phenols can be used in the production of pharmaceuticals and other fine chemicals.
(iii) Some of the chemicals can be used as organic solvents
The novel features of the invention when compared to the prior art
A typical comparison data for the oxidation of toluene with hydrogen peroxide by three catalysts in acetonitrile is given in the Table given below

• Ramaswamy and Sivasankar 1993
• *Sussaine et al 1983
V-NCL-1 the side chain oxidized product was the predominant one whereas the behaviour of vanadium heteropolymolybdat&resembled that of the vanadiumperoxo complex. But the reaction is homogeneous phase in vanadium complex and the preparation of the complex is comparatively more involved than the preparation of heteropolyvanadomolybdate.

Homogeneous oxidation of alkyl benzenes was carried out in the temperature range 303-335 K for three hours with acetonitrile as solvent. Hydrogen peroxide substrate ratio of 2.5 or tert-butyl hydroperoxide versus substrate ratio of nearly 1 was used in these experiments. After the experiment the products were extracted into dichloromethane and the catalyst was removed by washing with water. The products were analyzed both by GC-MS and GC alone.
The various catalysts were prepared by adopting suitable procedures for example H3PV2M010O40 and H3PV3M09O40 were prepared as red and deep red crystals by the stoichiometric addition of the oxides followed by acidification and esterification. Similarly special procedures were adopted for the synthesis other heteropoly compounds like H3PMo6W6O40, H4PVMo6W5O40, H5PV2W10O40 and K7Ti2W10P04o.
EXAMPLE
Typical data for the conversion of toluene with variation of vanadium content in heteropoly compounds, the effect of temperature and the variation of alkylbenzenes used are given in the following Tables 1-3

We Claims
1. A process for the homogeneous oxidation
of alkyl benzenes catalyzed by heteropoly
compounds for obtaining ring hydroxylated products
and side chain products, comprising the steps of
carrying out the homogeneous oxidation of the said
alkyl benzene in a solvent selected from (i)
acetonitrile (ii) acetic acid in the presence of
a heteropolymolybdate as catalyst, in a temperature range of 303 - 33S K, the oxidizing agent being selected from (i) hydrogen peroxide (i i) tert-butyl hydroperoxide; extracting the resulting products into dichloromethane; and removing the catalyst by washing with water.
2. A process as claimed in Claim 1 wherein the oxidation is carried'out for three hours.
3. A process as claimed in Claim 1 or Claim 2 WHEREIN the hydrogen peroxide to substrate ratio is 2.5
4. A process as claimed in Claim i or Claim 2

wherein the tert-butyl hydroperoxide to substrate ratio is nearly 1.
5. A process as claimed in any one of the preceding Claims wherein the catalyst used is a Vanadium-substituted heteropolymolybdate-
6. A process for the homogeneous oxidation
of alkyl benzenes catalysed by heteropoly' compounds to obtain fing hydroxylated products and side chain products, substantially as herein described and illustrated by the Example.
7. Ring hydroxylated products and side
chain products, whenever prepared by a process as claimed in any one of the preceding Claims.

Documents:

1090-mas-1999- abstract.pdf

1090-mas-1999- claims duplicate.pdf

1090-mas-1999- claims original.pdf

1090-mas-1999- correspondence others.pdf

1090-mas-1999- correspondence po.pdf

1090-mas-1999- descripition complete duplicate.pdf

1090-mas-1999- descripition complete original.pdf

1090-mas-1999- form 1.pdf

1090-mas-1999- form 26.pdf

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Patent Number

204528

Indian Patent Application Number

1090/MAS/1999

PG Journal Number

26/2007

Publication Date

29-Jun-2007

Grant Date

22-Feb-2007

Date of Filing

11-Nov-1999

Name of Patentee

INDIAN INSTITUTE OF TECHNOLOGY

Applicant Address

I.I.T.P.O.,CHENNAI 600 036

Inventors:

#	Inventor's Name	Inventor's Address
1	BALASUBRAMANIAN VISWANATHAN	INDIAN INSTITUTE OF TECHNOLOGY I.I.T.P.O.,CHENNAI 600 036
2	ATHILAKSHMI	B-5 ILLAM APARTMENTS,36,14TH CROSS STREET,NEW COLONY,CHROMEPET,CHENNAI 600 044I

PCT International Classification Number

C07C37/60

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA