Zhi Liu, Qiaoling Xu, Xutao Peng
Jun 15, 2010
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Journal
Journal of Molecular Catalysis A-chemical
Abstract
Abstract Montmorillonite was employed as a heterogeneous catalyst in the condensation of o -tert-butylaniline with paraformaldehyde for its significant confinement effect on the selective synthesis of 4,4′-diamino-3,3′-dibutyl-diphenyl methane (4,4′-MBTBA). Due to the appropriate d -spacing which is larger than the molecular size of 4,4′-MBTBA but smaller than that of 4,4′-(4-amino-5-tert-butyl-1,3-phenylene) bis(methylene)bis(2-tert-butylaniline) (PBMBA), montmorillonite favored the production of 4,4′-MBTBA, comparing with HY, P/SBA-15 and PW/C catalysts. In addition, with the decrease of the d -spacing of montmorillonite, the formation of PBMBA was inhibited and the selectivity of 4,4′-MBTBA became more and more remarkable, which verified the confinement effect as a tool for selectivity orientation on the heterogeneous synthesis of 4,4′-MBTBA over montmorillonite catalysts. When paraformaldehyde was used as starting material and the ratio of o -tert-butylaniline to paraformaldehyde was as low as 4:1, the yield of 4,4′-MBTBA reached 83.9% with butyl acetate as solvent, reaction temperature of 130 °C and catalyst loading of 0.18 g.