PURPOSE: To economically obtain the subject compound by treating a reactive mixture obtained by catalytic hydrogenation of the diester of maleic acid, fumaric acid, or succinic acid by use of four vacuum distillation columns.
CONSTITUTION: A mixture containing ethanol, tetrahydrofuran(THF), water, n-butanol, 1,4-butanediol(BD), diethyl succinate (BSDE) and γ-butyrolactone(GBL) is distilled with a first distillation column of which the theoretical number of plate is 5-25 operating at 50-500 mbar and 35-50°C of the column top temperature, to separate THF, water and up to 90% of ethanol from the column top. Then, the remaining fraction is distilled with a second column of which the plate number is 10-30 operating at 20-200 mbar and 45-60°C. The treated product containing ethanol, n-butanol, GBL, BSDE and BD at the column top is then supplied to a third column of which the plate number is 40-100, operating at 20-200 mbar and 50-65°C. Finally, the distilled product containing ethanol, n- butanol and GBL at the third column top is further distilled with a fourth column having 10-30 plates at 50-500 mbar and 45-55°C, and GBL is obtained from a side discharge port.
PEETAA SHIYUTOTSUPUSU
ERUBUIN BURUNNAA
RUDORUFU BUAIGANTO
