| 摘要 |
PURPOSE:To obtain methylene-bis-(4-phenylcarbamic acid ester) useful as a raw material of polyurethane, economically in an industrial scale, by the methylene- introducing condensation of N-phenylcarbamic acid ester with a dialkoxymethane in the presence of a specific solid acid catalyst. CONSTITUTION:The objective compound is prepared by condensing the N-phenylcarbamic acid ester of formula (R is alkyl, etc.; R' is H, alkyl, etc. bonded to the o- or m-position of the urethane group; m is 0-4) with the dialkoxymethane of formula CH2(OR)2 at <=250 deg.C under atmospheric pressure or positive pressure, in the presence of a solid acid catalyst obtained by the intercalation of a Lewis acid (e.g. CuCl2) in graphite. EFFECT:Since the catalyst is solid acid, various side reactions such as deactivation of the catalyst, partial dissolution of the catalyst components, etc. can be suppressed. The corrosion of the apparatus is reduced compared with the case using liquid acid catalyst. The operation is easy, the catalyst can be reused, and the discharge of the aqueous solution of the waste acid can be prevented. |
