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 6

IR spectra of fresh and reused NaY catalysts. (a) Fresh NaY; (b) NaY after used for the first time; (c) NaY after used for the second time.