| 摘要 |
PURPOSE:To easily produce a maleimide in a high yield and selectivity by using an N-unsubstituted maleamic acid ester as a starting raw material and imidating the ester by dealcoholic cyclization with a monoalkyl or monocycloalkylsulfuric acid ester. CONSTITUTION:This N-unsubstituted maleimide is produced by heating a maleamic acid ester compound of the formula I (R<1> is a 1-8C alkyl or a 3-8C cycloalkyl) together with a mono(cyclo)alkylsulfuric acid ester of the formula II (R<2> is a 1-8C alkyl or a 3-8C cycloalkyl) in an inert organic solvent to effect the dealcoholic cyclization reaction of the ester compound. The amount of the compound of the formula II is preferably 0.01-2mol based on 1mol of the compound of the formula I. The group R<1> of the compound of the formula I is preferably same as the group R<2> of the compound of the formula II. The preferable reaction solvent is, e.g. toluene or xylene. Homopolymerization or copolymerization of the maleimide by radical polymerization provides a heat- resistant thermoplastic resin. The maleimide is also useful as an intermediate for pharmaceuticals, agrochemicals, etc. |
