| 摘要 |
The present invention relates to a process for the selective preparation of 4,4-methylene-bis-(N-phenylalkylcarbamate) which comprises condensing N-phenylalkylcarbamate with a methylating agent in the presence of an acidic ion-exchange resin or an aqueous acid as a catalyst and a non polar aprotic solvent and filtrating a condensation product at a temperature greater than the melting point of N-phenylalkylcarbamate to separate 4,4-methylene-bis-(N-phenylalkylcarbamate).
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