Patent ID: 8299149

Claim:
A process for purifying hydroquinone bis-(diphenylphosphate) comprising: solvating molten hydroquinone bis-(diphenylphosphate) in a mixture of water and water miscible solvent at a temperature of at least 30 degrees Celsius or adding solid hydroquinone bis-(diphenylphosphate) to water and a water miscible solvent to a temperature sufficient to solvate the hydroquinone bis-(diphenylphosphate); cooling the solution over a period and to a temperature that provides for crystallization of hydroquinone bis-(diphenylphosphate) solid product; increasing the pH of the solution prior to, and/or during, and/or after the initiation of crystallization, and/or after crystallization of the product is complete, by the addition of a base; and after crystallization is complete, separating hydroquinone bis-(diphenylphosphate) solid product from the solution; washing the separated hydroquinone bis-(diphenylphosphate) solid product in the same and/or different mixture of water and water miscible solvent; and, washing the hydroquinone bis-(diphenylphosphate) solid product which has been washed in the mixture of water and water miscible solvent, with water.