PURPOSE: To produce a boric oxide in an anhydrous or hydrated form purely at a high conversion rate by hydrolyzing a methyl borate with water in a hydrolysis separation zone, introducing the hydrolyzed product to a distillation column, where azeotrope distillation is carried out through the introduction of two specific kinds of compounds.
CONSTITUTION: Water 14 and a methyl borate 12 at a molar rate of 1.3 or over are fed to a hydrolysis reactor R1. Then the hydrolyzed product (boric oxide + methanol) and a compound A to produce a heteroazeotrope with the methanol are introduced to a distillation column C3 (a boiling point of the heteroazeotrope is lower than a boiling point of a methyl borate - methanol azeotrope mixture). Furthermore, a compound B (not forming an azeotrope with a boiling point below that of the heteroazeotrope) having a boiling point higher than that of the methyl borate is introduced to the column. Then the heteroazeotrope 16 is recovered from the head of the column, and fed to a decanter D, where the heteroazeotrope is separated into a methanol and the compound A, and the compound A is circulated 18. A mixture 19 of the boric oxide and the compound B is recovered from the bottom of the column.
KURISUCHIYAN BUSAN
RIYONERU ASURINOO
