a time period of about 4 1 2 hours the liquid mixture remaining was drained off and the temperature inside the apparatus was slowly increased until the freezing point of the runoff was 3 9 u00b0 c the crystals in the apparatus were then melted and isolated the contaminated fractions obtained as runoff were further processed subsequently as described in examples 4 and 5 below thus it was discovered that using a starting crude product mixture of 132 7 parts by weight 100 parts by weight of purified 4 acetoxystyrene was produced the overall yield including the amount of 4 acetoxystyrene obtained by subsequent processing as described in examples 4 and 5 and calculated on the basis of a sankey diagram was 75 6 the pure 4 acetoxystyrene product had a freezing point of 7 1 u00b0 c and a purity of 99 3 a 4 acetoxystyrene comprising mixture having a freezing point of 1 2 u00b0 c and a purity of 89 6 was placed in the crystallizing apparatus previously described in example 1 and was processed using the techniques described therein the liquid mixture was cooled to 1 1 u00b0 c and seeded with a few seed crystals of 4 acetoxystyrene after a crystallization time at 1 1 u00b0 c of about half an hour the crystallizer contents were cooled over a time period of about 6 1 4 hours to 14 7 u00b0 c the liquid portion of the mixture remaining in the crystallization apparatus was then drained off and the temperature of the remaining crystalline contents was slowly raised until the freezing point of the runoff was 3 7 u00b0 c the colorless crystals.