Research Article

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

Figure 2

MS spectra of the by-products 1, 2, and 3. Subfigures (a), (b), and (c) present the MS spectra of the pseudomolecular ions of compounds 1, 2, and 3, respectively. 4 stands for the ion with an m/z value of 106.
(a)
(b)
(c)