We Claim:
1. A process for preparation of edaravone comprising;
a) treating phenyl hydrazine acid addition salt with base followed by a reaction with alkylacetoacetate,
b) adjusting pH of the reaction mass obtained in step (a) between 7.5 and 8.0 using acid and
c) isolation.
2. The process according to claim 1, wherein the base used in step (c) is selected from sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide and magnesium hydroxide.
3. The process according to claim 1, wherein the alkylacetoacetate is selected from methylacetoacetate and ethylacetoacetate.
4. The process according to claim 1, wherein the pH of the reaction mass is adjusted between 7.5 and 8.0 using acid selected from HC1, H2SO4 and acetic acid in step (b).
5. The process according to claim 4, wherein the pH is adjusted between 7.8 and 8.0.
6. The process according to claim 4, wherein the acid is aqueous hydrochloric acid.
7. A process for preparation of pure edaravone comprising;
a) Dissolving edaravone in alcoholic solvent under heating,
b) Cooling the solution obtained in step (a) and
c) Isolation.
8. The process according to claim 7, wherein the alcohol solvent is methanol, ethanol and propanol.
9. The process according to claim 7, wherein the solution is cooled to 0-10°C in step (b).
10. The process according to claim 7, wherein the pure edaravone is characterized by x-RPD values comprising 9.7, 11.2, 12.6, 13.5, 14.7, 16.7, 17.2, 18.0, 19.1, 19.7, 21.3, 23.3, 23.8, 24.3, 25.3 and 26.4 ±0.2e.