Full N,N-Methylation of 4,4′-Methylenedianiline with Dimethyl Carbonate: A Feasible Access to 4,4′-Methylene bis(N,N-Dimethylaniline)

Abstract

The full N,N-methylation of 4,4 -methylenedianiline (MDA) with dimethyl carbonate (DMC) was investigated. The yield of the major product 4,4 -methylene bis(N,N-dimethylaniline) (MBDMA) reached as high as 97% over NaY catalyst at 190 ∘ C for 6 h. The catalyst could be used for two more times with acceptable MBDMA yields higher than 90%. The main by-products were identified as three N-methylated derivatives. Surprisingly, the formation of the N-methoxycarbonylation product was extremely restrained, which could be produced in high yields of 98% on zinc acetate catalyst. Furthermore, the reaction pathway to the major product MBDMA was proposed. Finally, a feasible synthetic route of 4,4 -methylene bis(N,N-dimethylaniline) (MBDMA) was established, featuring a high yield, mild reaction conditions, and simple operations.

Deamination of Polyols from the Glycolysis of Polyurethane

“…This trend may be explained considering that in all three cases other reactions involving other less reactive NÀ H groups [47,48] present in the recycled polyol occur, however the higher the molar excess, the higher the diminishing of MDA content. Diamines, indeed, present four reactive sites [49] represented by each active hydrogen linked to the nitrogen. They are commonly used in the curing reactions of epoxy resins [50] .…”