反应详情

An aqueous solution (200 ml) of phthalide (134 g) and sodium hydroxide (40 g) was heated. After stirring for 1 hour, the mixture was concentrated under reduced pressure for removal of water to obtain sodium 2-hydroxymethylbenzoate as colorless crystals. p-Cymene (480 ml) and 2,5-xylenol (122 g) were added to the crystals. Azeotropic dehydration was carried out with heating under reflux for 7 hours by using an azeotropic dehydration apparatus. After cooling, ice water was added. Concentrated hydrochloric acid was added dropwise to make the mixture acidic. The precipitates were separated by filtration and recrystallized from ethyl acetate to obtain the title compound (155 g, Yield: 60.5%), mp: 162°-163° C.

1. concentrationthe mixture was concentrated under reduced pressure for removal of water