PURPOSE: To obtain a polymethylenepolyphenylcarbamate having no cyclic structural unit in high purity and yield by subjecting a compound having a specific cyclic structure to ring-opening condensation reaction using an acid catalyst.
CONSTITUTION: A compound expressed by formula I (R is 1-6C alkyl, cycloalkyl or aryl) is subjected to ring-opening condensation reaction using an acid catalyst such as mineral acid, organic carboxylic acid, organic sulfonic acid, Lewis acid or heteropolyacid (preferably methanesulfonic acid or trifluoromethane sulfonic acid) at 20-150°C, preferably 50-120°C to provide the objective compound expressed by formula II ((n) is integer of ≥0). The compound expressed by formula I is obtained by e.g. reacting N-phenylcarbamate with formaldehyde in the presence of an acid catalyst and separating and recovering the compound from the resultant reactional products. Polymethylenepolyphenylcarbamates having a high isocyanate group content can be produced by pyrolytic reaction of the compound expressed by formula II. The resultant carbamate derivatives are useful in rigid foam field.
MIYAZAWA MAKOTO
YAMAMOTO SACHIKO
FUJIMURA KATSUNORI
HIGUCHI SHINYA