METHOD FOR PRODUCING PENTAERYTHRITOL Russian patent published in 1998 - IPC

FIELD: organic synthesis; production of pentaerythritol used in lacquers, varnishes, paints, etc. SUBSTANCE: pentaerythritol has the following characteristics: formula C₅6₁₂O₄,; average crystal size, 0.25-0.27 mm; duration of cooling and crystallization processes, 90-100 min. Method resides in reacting acetaldehyde with formaldehyde in presence of sodium hydroxide, followed by subjecting resulting reaction mass to rectification, thickening by evaporation, crystallization under cooling conditions. Cooling is also accompanied with stirring in pulsed mode with pulse amplitude 0.2-0.5 m and frequency 10-40 vibrations/min. Cooling is conducted stepwise with temperature difference 2-4 C between neighboring steps, simultaneously, recirculating portion of reaction mass in the amount 10-20% of total amount of reaction mass from each subsequent cooling step to preceding one. EFFECT: improved quality of product. 1 tbl