Preparation of carbamates from aromatic amines and organic carbonates
申请人:THE DOW CHEMICAL COMPANY
公开号:EP0065026A1
公开(公告)日:1982-11-24
This invention is directed to a process for preparing a carbamate from an organic carbonate and an aromatic amine in the presence of catalytic quantities of a Lewis acid catalyst. The Lewis acid catalyst is soluble in the reaction mixture at the reaction conditions employed and is at least one member of the group consisting of a zinc or divalent tin halide, a zinc or divalent tin salt of a monovalent organic compound which has a pKa value of at least 2.8, and a zinc or divalent tin salt of trifluoroacetic acid.
The zinc thiodipropionatecomplex [Zn(tdp)] (1) [tdp = S(CH2CH2COO)22–] was obtained by reaction of aqueous zinc dichloride with a 1:1 mixture of Na2CO3 and thiodipropionic acid. The bonding preferences of the tdp anion were studied by DFT methods. The reaction of 1 with o-phenanthroline (phen) gave the dinuclear compound [Zn(phen)(H2O)}2(μ-tdp)2]·3H2O (2), which was characterized by X-ray analysis