Synthesis Of 4,4'-diaminodiphenyl Methane Derivatives Over Solid Acid Catalysts

4,4'-diamino diphenyl methane (DMA) derivatives are important for the preparation of diphenyl-methane-diisocyanate, corrosion inhibitor and epoxy resins. With traditional synthesis method, DMA was prepared through the alkylation of anline with formaldehyde with liquid acid as a catalyst, such as HCl, H2SO4, HNO3. In this dissertation, phosphoric acid modified SBA-15 (P/SBA-15) was employed as catalyst in the synthesis of 4,4'-diamino-3,3'-dibutyl-diphenyl methane (4,4'-MBTBA) via condensation of o-tert-butylaniline with paraformaldehyde. The results showed that weak acid centers exhibited considerable activity and the yield reached 50% under the optimized term.Experiments further explored catalytic performance of acidic montmorillonites for the synthesis of 4,4'-MBTBA. The results showed montmorillonite favored the production of 4,4'-MBTBA, comparing with HY, P/SBA-15 and PW/C. Montmorillonites displayed distinct shape-selectivity on the reaction and the yield reached 83.9% under the optimized term.Moreover, diaminotriphenylmethanes were synthesized from anline and aromatic aldehyde on different solid acid catalysts. Acidic catalysts showed the moderate activity on the synthesis of diaminotriphenylmethanes under solvent-free conditions.