METHOD OF PREPARING PENTAERYTHRITOL Russian patent published in 2002 - IPC

FIELD: organic synthesis. SUBSTANCE: pentaerythritol is prepared by reaction of acetaldehyde with excess formaldehyde in presence of sodium hydroxide. Process involves evaporation of reaction solution, crystallization, filtration, washing, and drying of final product. Excess of formaldehyde comes up to 50% of its stoichiometric amount and process is conducted until conversion of aldehydes in presence of boric acid or borax (0.015-0.02 mol per 1 mol acetaldehyde) is completed. Evaporation is realized partially. First, operation is continued until density 1.05-1.12 g/cu.cm is attained, after which solution is subjected to crystallization and dipentaerythritol is separated. Remaining mother solution is subjected to an additional evaporation followed by crystallization and isolation of pentaerythritol. EFFECT: increased purity of product. 5 cl, 1 tbl, 4 ex