The chitosan was found to possess an excellent catalytic performance in n-butyraldehyde selfcondensation to 2 E2 H.Under suitable conditions,the conversion of n-butyraldehyde,the yield and selectivity of 2 E2 H separa...The chitosan was found to possess an excellent catalytic performance in n-butyraldehyde selfcondensation to 2 E2 H.Under suitable conditions,the conversion of n-butyraldehyde,the yield and selectivity of 2 E2 H separately attained 96.0%,86.0%and 89.6%.The chitosan catalyst could be recovered and used for 5 times without a significant deactivation after being treated with ammonium hydroxide.In order to elucidate the reaction mechanism,the adsorption and desorption of n-butyraldehyde on the surface of chitosan were studied using in situ FT-IR spectroscopy analysis.The result showed that n-butyraldehyde interacts with\\NH2 group of chitosan to form an intermediate species with an enamine structure.Then the reaction process of n-butyraldehyde self-condensation was monitored by React-IR technique and it was found that n-butyraldehyde self-condensation to 2-ethyl-3-hydroxyhexanal followed by a dehydration reaction to 2-ethyl-2-hexenal.On this basis,chitosan-catalyzed n-butyraldehyde self-condensation reaction mechanism was speculated and its reaction kinetics was investigated.The self-condensation reaction follows auto-catalytic reaction characteristics and then the corresponding kinetic model was established.展开更多
基金Supported by National Natural Science Foundation of China(21476058,21506046)Natural Science Foundation of Tianjin City(16JCQNJC06100).
文摘The chitosan was found to possess an excellent catalytic performance in n-butyraldehyde selfcondensation to 2 E2 H.Under suitable conditions,the conversion of n-butyraldehyde,the yield and selectivity of 2 E2 H separately attained 96.0%,86.0%and 89.6%.The chitosan catalyst could be recovered and used for 5 times without a significant deactivation after being treated with ammonium hydroxide.In order to elucidate the reaction mechanism,the adsorption and desorption of n-butyraldehyde on the surface of chitosan were studied using in situ FT-IR spectroscopy analysis.The result showed that n-butyraldehyde interacts with\\NH2 group of chitosan to form an intermediate species with an enamine structure.Then the reaction process of n-butyraldehyde self-condensation was monitored by React-IR technique and it was found that n-butyraldehyde self-condensation to 2-ethyl-3-hydroxyhexanal followed by a dehydration reaction to 2-ethyl-2-hexenal.On this basis,chitosan-catalyzed n-butyraldehyde self-condensation reaction mechanism was speculated and its reaction kinetics was investigated.The self-condensation reaction follows auto-catalytic reaction characteristics and then the corresponding kinetic model was established.
