Phosphoric acid modified SBA-15 as a highly efficient heterogeneous catalyst for the synthesis of 4,4′-diamino-3,3′-dibutyl-diphenyl methane

Phosphoric acid modified SBA-15 (P/SBA-15) was employed as catalyst in the synthesis of 4,4′-diamino-3,3′-dibutyl-diphenyl methane (MBTBA) via condensation of o-tert-butylaniline with paraformaldehyde. It performed more efficiently than HY, kaolinite, γ-Al2O3 in heterogeneous reaction and HCl in homogeneous catalysis did. The catalyst preparation and reaction conditions were investigated and the yield reached 50% under the optimized term. The BET and Py-FTIR results suggested that the excellent performance of P/SBA-15 in the synthesis of MBTBA should be attributed to the weak acidity of the material and its large pore size that facilitated the diffusion of substrate and product.