Insights on the mechanism for synthesis of methylenedianiline from aniline and formaldehyde through HPLC–MS and isotope tracer studies

The mechanism for synthesis of 4,4-methylenedianiline (MDA) via condensation reaction of aniline with formaldehyde has been studied extensively in this paper. The intermediate and by-products were isolated and identified. The combination of isotope labeling and HPLC–MS characterizations disclosed that the reaction proceeded through an SN2 reaction mechanism. Moreover, the effect of aniline/formaldehyde molar ratio on the formation of MDA was investigated. This work would be of significance to understand the reaction mechanism deeply and provide valuable information for further improving the yield of desired product.