AN Hualiang, TIAN Jinping, ZHAO Xinqiang, et al. Preparation of silica-immobilized SO3H-functionalized ionic liquids and its catalytic activity in reaction of 4, 4'-methylenedianiline synthesis[J]. CIESC Journal, 2015, (S1): 171-179. DOI: 10.11949/j.issn.0438-1157.20150041.
DOI:
AN Hualiang, TIAN Jinping, ZHAO Xinqiang, et al. Preparation of silica-immobilized SO3H-functionalized ionic liquids and its catalytic activity in reaction of 4, 4'-methylenedianiline synthesis[J]. CIESC Journal, 2015, (S1): 171-179. DOI: 10.11949/j.issn.0438-1157.20150041.DOI:
Preparation of silica-immobilized SO3H-functionalized ionic liquids and its catalytic activity in reaction of 4, 4'-methylenedianiline synthesis
Immobilized SO3H-functionalized ionic liquids were prepared by three different pathways and their catalytic performance was evaluated in the condensation reaction for the synthesis of 4
4'-methylenedianiline (4
4'-MDA) from aniline and HCHO
and the reusability of the immobilized ionic liquids were investigated. The result showed that ionic liquid loading in the immobilized ionic liquids was consistent with their catalytic activity. Among the immobilized ionic liquids
SiO2@[HSO3-ppim]CF3SO3-Ⅰ with the highest loading showed the best catalytic activity. Then the influence of reaction conditions on the synthesis of 4
4'-MDA was investigated using SiO2@[HSO3-ppim]CF3SO3-Ⅰcatalyst. The suitable reaction conditions were as follows: mass ratio of catalyst to HCHO was 1.5
molar ratio of aniline to HCHO was 4
reaction time of 7 h
and reaction temperature of 80℃. Under the above conditions
the yield and selectivity of 4
4'-MDA were 74.9% and 94.5%
respectively. However
the catalytic activity of the recovered catalyst declined dramatically. The results of acid-base titration and FT-IR spectroscopy analyses showed that there was a chemical interaction between the immobilized ionic liquids and aniline. The deactivated immobilized ionic liquids could be regenerated by acidization with CF3SO3H
and the acidized immobilized ionic liquids could be reused four times with a tolerable loss of its catalytic activity.