filter and the precipitate was washed with water and dried in an oven at 60 u00b0 70 u00b0 c the yield of bis n n 39 para nitrobenzoyl hexafluoro 2 2 bis 4 hydroxyphenyl propane was 93 6 of theoretical the product of example 1 was purified by recrystallization in accordance with the following method 1000 ml round bottom flask equipped with a mechanical stirrer was charged with 51 0 grams of the crude product of example 1 316 grams of acetone and 158 grams of methanol the mixture was stirred and heated at 40 u00b0 50 u00b0 c until the product of example 1 had dissolved the mixture was cooled to room temperature and 30 grams of norite was gradually added after which the mixture was stirred for about 25 minutes the mixture was then clarified by passing it through a 9 cm buchner funnel and using a small amount of a 2 to 1 mixture of acetone methanol as a rinse the clarified solution was then transferred to a beaker and heated to 50 u00b0 55 u00b0 c 300 mls of warm tap water was added dropwise to the solution over a period of 30 minutes after which the solution was heated to 60 u00b0 65 u00b0 c after removal from the.