The methoxycarbonylation mechanism of synthesizing 2,4-toluene dicarbamate from 2,4-toluene diamine and dimethyl carbonate catalyzed by anhydrous zinc acetate was investigated by Fourier transform infrared spectroscopy.The result shows that the new coordination complex was formed by oxygen atom of dimethyl carbonate’s carbonyl group attaching to zinc atom of anhydrous zinc acetate to form the Zn—O coordination bond,and the anhydrous zinc acetate changed from a bidentate ligand to a unidentate ligand.Simultaneously,dimethyl carbonate’s carbonyl group was activated.2,4-toluene diamine was a nucleophilic reagent,and it’s amidos attacked the activated carbon of dimethyl carbonate’s carbonyl group in the new coordination complex to produce the methoxycarbonylation compound 2,4-toluene dicarbamate,then the Zn—O coordination bond in the new coordination complex was broken.At the same time,the anhydrous zinc acetate returned to a bidentate ligand.