We claim:
1. A process for the preparation of Glycerol phenylbutyrate (1) having purity
greater than 99.0% comprising:
a) reacting glycerol (2) with 4- phenylbutyric acid (3) in the presence of a base and a coupling agent; and
b) isolating Glycerol phenylbutyrate (1).

2. The process according to claim 1, wherein the base used in step a) is selected from triethyl amine, imidazole, pyridine, and picoline.
3. The process according to claim 1, wherein the solvent used in step a) is selected from dimethylformamide (DMF), and dimethylsulfoxide (DMSO).
4. The process according to claim 1, wherein the coupling agent used in step a) is selected form Diisopropylcarbodiimide (DIC), Dicyclohexyl carbodiimide (DCC), N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC.HC1), U'-Carbonyldiimidazole (CDI), and 1-Hydroxybenzotriazole (HOBt).

5. The process according to claim 1, wherein the base used is catalytic amount of 4-Dimethylaminopyridine (DMAP).
6. A process for the purification of Glycerol phenylbutyrate (1), comprising

a) providing a solution of Glycerol phenylbutyrate (1) in a protic solvent;
b) heating the reaction mixture to a suitable temperature;
c) separating organic layer;
d) adding an aprotic solvent to the product layer;
e) adding activated carbon and filtering; and
f) isolating pure Glycerol phenylbutyrate (1).
7. The process according to claim 6, wherein the protic solvent used in step a)
is selected form methanol, ethanol, isopropyl alcohol and water.
8. The process according to claim 6, wherein the aprotic solvent used in step
d) is selected form dichloromethane, n-hexane, n-heptane, cyclohexane, and
acetonitrile.

9. The process according to claim 6, wherein the suitable temperature employed in step b) is 50-60 °C.
10. The process according to claim 6, wherein the Glycerol phenylbutyrate (1) having purity greater than 99.0% and one more of the following

a) less than 0.05% of Impurity B;
b) less than 0.05% of impurity C; and
c) less than 0.05% of impurity D.