FORM NO 2
THE PATENTS ACT, 1970 (39 OF 1970)
COMPLETE SPECIFICATION
[See sections 10 and Rule 13]
TITLE PROCESS FOR MANUFACTURE OF
POLYVINYLPYRROLIDONE
APPLICANT BALAJI AMINES LIMITED
ADDRESS 165/A, Balaji Bhavan, Railway Lines,
Solapur- 413 001.
NATIONALITY Indian
The following specification describes the nature of this invention and the manner in which it is to be performed:

TITLE
PROCESS FOR MANUFACTURE OF POLYVINYLPYRROLIDONE FIELD OF INVENTION:
The present invention relates to an improved process for manufacture polyvinyl pyrrolidone (PVPK-30) by polymerization of N-Vinyl pyrrolidone in the presence of hydrogen peroxide, ammonia, and copper sulphate catalyst.
BACKGROUND OF THE INVENTION:
Vinyl pyrrolidone polymer is generally used in various applications like pharmaceuticals and cosmetics. In particularly they are used as binders, tablet coating agents, suspension stabilizers and solublizers. In cosmetics they are used as thickeners, dispersants, lubricants and binders. Due to toxicological reasons the polymer which is used should be as free as possible from its monomers and impurities.
In the polymerization of N-Vinyl pyrrolidone with hydrogen peroxide as an initiator in aqueous medium, wherein the pH of the reaction will drop below 7 which leads to decomposition of N-Vinyl pyrrolidone leading to formation undesirable side products. The decomposed reaction products lead to discoloration of polymer solution. Customarily the decrease in the pH of the reaction mass can prevented by continuous addition of ammonia, however this leads to the formation of undesirable hydrazine impurity.
US patent No 2009/0124775A1 discloses the process for producing vinylpyrrolidone polymer in solution by polymerization of vinyl pyrrolidone using aqueous hydrogen peroxide , ammonia in

presence of catalytic amount of copper sulphate. Under these conditions it is very difficult to control the heat of polymerization and the temperature of the polymerization reaction is very high which leads to the decomposition of vinyl pyrrolidone. The impurities formed by the side reaction of N-vinyl pyrrolidone monomer leads to the discoloration of the polymer. As per the Pharmacopeal standards there should not be any color to polyvinyl pyrrolidone which is used in cosmetics and pharmaceutical products.
It is seen that when free radical initiators such as Azoisobutyronitrile is used in the polymerization of vinyl pyrrolidone under conventional reaction conditions in aqueous medium using ammonia for pH maintenance, hydrazine has been found in finished product which cannot be tolerated for polymers used in drugs and cosmetics.
Under the above described circumstances, the problems to be solved by present invention are to provide a high quality Polyvinylpyrrolidone powder having good color, low impurities, and k-values below 35 in a simple and easy manner.
The polymerization is carried out at lower temperature to avoid the decomposition of N-vinyl pyrrolidone and discoloration of polymer solution. Hence the pH of the polymer solution is maintained by using dilute alkali solution by continuous adding the alkali solution to the polymerizer at definite intervals of time to avoid the side reactions.

OBJECTIVE OF THE INVENTION:
■ To carry out the polymerization reaction at low temperature to avoid decomposition of N-vinyl pyrrolidone
■ To perform the reaction at very low catalyst concentration
(ppb level) to avoid the catalyst in the finished product.
■ To prepare the high purity polyvinyl pyrrolidone by purifying the polymer solution using cation exchange resin to reduce the unreacted N-vinyl pyrrolidone content and other undesirable degradation products in the final product.
■ To improve the color of the polymer by performing the reaction at very low temperature.
■ To prepare Polyvinylpyrrolidone having low monomer content and lesser impurities.
• Preparation of polyvinyl pyrrolidone polymer having a Fikenster's K-Value of 35 or below.
■ It is an object of the present invention to find process for
preparation of such polymers without hydrazine impurity in
the Final product.

DEATAILED DISCRIPTION OF THE INVENTION:

1000 ml of distilled water is charged into clean three necked round bottom flask. Charged 500 ml of freshly distilled N-vinylpyrrolidone having the purity more than 99%. Start purging nitrogen gas in to the reactor continuously. Added 0.000005 parts of copper sulphate (relative to N-vinylpyrrolidone) in to the reactor and started heating to 40°C. Charged 9.0 ml of 35% hydrogen peroxide and 2.0 ml Of 20 % aqueous ammonia solution controlled the exotherm of the reaction to 60 °C and maintained at same temperature for another 5-6 hrs. The resulting polymer solution has K-value of 29.5, monomer content of 0.12%.
33% polymer solution obtained above was passed through resin column at rate of 3 bed volumes per hour over a cation ion exchange resin column. The vinyl pyrrolidone monomer reduced from 1200 ppm to 3.6 ppm. Adjusted the pH of the polymer using aqueous ammonia solution.
3.0 gms of activated carbon is added to the reactor and stirred for
four hrs at 40°C . Filtered.

We Claim
1. A process to obtain high purity polyvinyl pyrrolidone by purifying the polymer solution using cation exchange resin to reduce the unreacted N-vinyl pyrrolidone content and obtain polyvinyl, pyrrolidone with K- value of about 25-35 useful preferably in pharmaceutical and cosmetic applications.
2. A process as claimed in claim 1 of above wherein polyvinyl pyrrolidone is obtain and which includes vinyl pyrrolidone monomer less then 10 ppm and having K-value from 25-35
3. A process as claimed in 1 and 2 above wherein purification of the polymer solution is carried out using cation exchange resin to remove the residual NVP content and other basic impurities to obtain polyvinyl pyrrolidone with high purity.
4. A process as claimed in claim 1 to 3 above wherein the reaction is performed at a very low temperature at 40°C
5. A process as claimed in claimed 1 to 4 above wherein capper sulphate is used as a polymerization catalyst in preparation of polyvinyl pyrrolidone
6. A process as describe hereinabove to obtain polyvinyl pyrrolidone.