Patent ID: 9062161
Filing Date: 2015-06-23
Classification: C07C,C08G,Y02P

Abstract:
1. A method for preparing polymethylene polyphenyl polycarbamate that is carried out through a condensation of phenylcarbamate with a methylating reagent under a catalyzation of a phase transfer acid catalyst, comprising the steps of: a) dissolving phenylcarbamate in a water-immiscible organic solvent to form a solution A; b) formulating an aqueous acid catalyst solution to form a solution B; c) forming a reaction system comprising an organic phase and an aqueous phase by firstly adding a methylating reagent to the solution B and then mixing the solution A and the solution B, or by adding the methylating reagent at the same time of mixing the solution A and the solution B or after mixing the solution A and the solution B, wherein the organic phase comprises phenylcarbamate and the aqueous phase comprises the phase transfer acid catalyst and the methylating reagent; d) reacting the reaction system under stirring at a reaction temperature of about 30° C. to about 200° C. and a reaction pressure of about 0.05 MPa to about 5 MPa to produce a polymethylene polyphenyl polycarbamate product mixture dissolved in the organic phase; and e) separating the polymethylene polyphenyl polycarbamate product mixture by allowing the organic phase and the aqueous phase to stand still and stratify.