FORM 2
PATENT ACT 1970
(39 OF 1970)
COMPLETE SPECIFICATION
(FORM-2)
TITLE - Process and Composition for Benzeneseleninic Anhydride.
NAME OF APPLICANT- OMKAR SPECIALITY CHEMICALS LTD.
ADDRESS OF APPLICANT- B-34, M.I.D.C. Badlapur (E), Dist-Thane, Maharashtra, Pin Code : 421503, India
PREAMBLE OF INVENTION- This invention in particular describes the nature of the invention and the manner in which it is.to be performed.

FIELD OF INVENTION - The present invention relates to a new process and composition for producing Benzeneseleninic Anhydride which is an extremely versatile oxidant. More particularly, the invention relates to a process for producing Benzeneseleninic Anhydride possessing high purity in high yield.
PRIOR ART-
In the existing system as given in ChemYQ, a preparation of Benzeneseleninic is disclosed, wherein diphenyl diselenide soluble carbon tetrachloride, in the -5 ° C leads to ozone absorption reaction, and then steamed decompression except that the solvent carbon tetrachloride in the goods.
In the existing system as given in Chemical and Pharmaceutival Bulletin, Vol. 52 (2004), No. 8 1009, titled Selective Oxidation of Alcohols at the Benzylic Position by Benzeneseleninic Anhydride by Department of Chemistry, Faculty of Science, Tokyo University of Science, a preparation of, wherein the excerpt of research mentions as follows. Benzeneseleninic anhydride (BSA) is easily prepared from diphenyl diselenide by oxidation with ozone or tert-butyl hydroperoxide (TBHP) and is now commercially available.
In the existing system as given in Journal of Chemical Society: Perkin transactions I., Issues 1-6, Page 471, Benzeneseleninic anhydride (mp 163 — 165 °C) was prepared from diphenyl diselenide and t-butyl hydroperoxide (3 mol equiv.)
OBJECT OF THE INVENTION - Benzeneseleninic Anhydride (BSA) has the chemical formula [C6H5Se(0)]20 and it can be produced in various ways. Numerous processes and process improvements have been disclosed in prior art.
[2]

However, some of the method involved earlier is evidently unsatisfactory, both economically and technically.
It is an object of the present invention to provide a simpler and more economical method of preparation of Benzeneseleninic Anhydride (BSA), in view of the unsatisfactory process hitherto disclosed. This object is achieved, and Benzeneseleninic Anhydride (BSA) is obtained in high yield and high purity.
STATEMENT OF INVENTION- The inventor has invented a new process and composition for preparing Benzeneseleninic Anhydride (BSA)
DETAILED DESCRIPTION OF INVENTION-
Accordingly, the present invention provides a process for producing -Benzeneseleninic Anhydride (BSA) and high-purity - Benzeneseleninic Anhydride.
1. A process for producing Benzeneseleninic Anhydride (BSA) involves step of Charging 3.33 lit. toluene.
2. A process for producing Benzeneseleninic Anhydride (BSA) further involves step of adding 1.11 kg. Benzene seleninic acid to charged 3.33 litre toluene under stirring.
3. A process for producing Benzeneseleninic Anhydride (BSA) further involves step of heating the reaction mixture at 108 - 110°C to reflux using Dean -stark apparatus for 3 to 4 hours, resulting in change of colour of the reaction mixture to Coca-Cola colour.
[3]

4. A process for producing Benzeneseleninic Anhydride (BSA) further involves continuation of heating the reaction mixture for further 1-1,5 hour, till the colour of reaction mixture changes from Coca-cola to orange.
5. A process for producing Benzeneseleninic Anhydride (BSA) further involves stirring the reaction mixture for 1 hour time.
6. A process for producing Benzeneseleninic Anhydride (BSA) further involves cooling the reaction mixture at room temperature.
7. A process for producing Benzeneseleninic Anhydride (BSA) further involves filtering and washing the reaction mixture with n-pentane (slurry wash).
8. A process for producing Benzeneseleninic Anhydride (BSA) finally involves drying under vacuum to get Melting point of 165-172 °C and high purity Benzeneseleninic Anhydride (BSA) is finally prepared
Raw materials involved are given as under along with their proportion

• Benzene seleninic acid : 1.11kg
• Toluene : 3.33 lit.
• N-pentane : 1.63 lit.

The process according to the invention can be carried out batchwise or by conventional continuous techniques. The continuous operation is technically particularly simple and also economical, compared to the Benzeneseleninic Anhydride (BSA) syntheses of the prior art.
Based on process employed, the resultant Benzeneseleninic Anhydride (BSA) (which is in fact more than 99% pure) is obtained in yields of 90% or more.
Next, the present invention shall more specifically be explained with reference to examples. However, the present invention shall by no means be restricted by the following examples.
Example 1 - The step involving reflux of the toluene in the dean stark apparatus is done in a stainless steel reactor or a glass lined reactor or an enamelled reactor or any other vessel which can resist corrosion of the aforesaid reaction mix may be used.
Example 2 - In the place of toluene, xylenes of various types may be used or any other solvent which is inert to the reaction mixture and is capable of Azeotropic water removal is permitted.
Example 3 - In place of pentane in the final step, any other solvent belonging to class of Hydrocarbons and capable of removing toluene trapped in the wet cake is permissible. Example includes N-Heptanes, N-Hexane or Octane.
Example 4 - The process can also be conducted by totally bypassing pentane wash and vacuum drying the product as it is.
Since expensive metals and specific reagents do not have to be used, it can readily be carried out in an industrially scale, and the product having a high purity can be obtained.
[5]

Further, the process of the present invention makes it possible to readily obtain at a high yield, Benzeneseleninic anhydride having a high purity. The steps are simple in terms of a procedure, and it is very advantageous in industrially carrying out
Benzeneseleninic anhydride can also be used as a new side-chain oxidant for a variety of aromatic and hetero aromatic hydrocarbons.

CLAIMS
I claim,
1. A process for producing Benzeneseleninic Anhydride (BSA) by refluxing Benzeneseleninic acid in toluene in order to remove H2O; cooling to room temperature, filtering and vacuum drying.
2. A process for producing Benzeneseleninic Anhydride (BSA) as per claim 1, comprising of charging 3.33 litre toluene.
3. A process for producing Benzeneseleninic Anhydride (BSA) as per claim 1, further comprising of adding 1.11 kg. Benzene seleninic acid to charged 3.33 litre toluene under stirring.

4. A process for producing Benzeneseleninic Anhydride (BSA) as per claim 1, further comprising of heating the reaction mixture to reflux using Dean -stark apparatus for 3 to 4 hours, until no more water was collected in the dean stork apparatus; resulting in change of colour of the reaction mixture to Coca-Cola colour
5. A process for producing Benzeneseleninic Anhydride (BSA) as per claim 1, further comprising of continuation of heating the reaction mixture for further 1 -1.5 hour, till the colour of reaction mixture changes from Coca-cola to orange
6. A process for producing Benzeneseleninic Anhydride (BSA) as per claim 1, further comprising of stirring the reaction mixture for 1 hour time.
[8]

7. A process for producing Benzeneseleninic Anhydride (BSA) as per claim 1, further comprising of cooling the reaction mixture at room temperature.
8. A process for producing Benzeneseleninic Anhydride (BSA) as per claim 1, further comprising of filtering and washing the reaction mixture with n-pentane (slurry wash)
9. A process for producing Benzeneseleninic Anhydride (BSA) as per claim 1, finally involves drying under vacuum to get Melting point of 165-172 °C and high purity Benzeneseleninic Anhydride (BSA) is finally prepared.