Alkylation of toluene With 2-chloro-2-methylpropane （t-Bu-C1） to synthesize para-tert-butyltoluene （PTBT） was carded out in the presence of triethylamine hydrochloride-aluminum chloride ionic liquids used as the c...Alkylation of toluene With 2-chloro-2-methylpropane （t-Bu-C1） to synthesize para-tert-butyltoluene （PTBT） was carded out in the presence of triethylamine hydrochloride-aluminum chloride ionic liquids used as the catalyst. The ionic liquids were prepared with different molar ratios of Et3NHC1 to A1CI3, and the effect of the molar ratio between A1C13 and Et3NHC1, the reaction time, the reaction temperature, the ionic liquid dosage, as well as the molar ratio of toluene to chloro- 2-methylpropane on the alkylation reaction of toluene with chloro-2-methyl-propane was investigated. The test results showed that the acidic ionic liquids prepared with Et3NHC1 and A1C13 had good activity and selectivity for the alkylation reaction of toluene with alkyl chloride to produce PTBT. The optimal reaction conditions were specified at an A1C13 to Et3N- HCI ratio of 1.6, a reaction temperature of 20 ℃, a mass fraction of toluene to ionic liquid of 10%, and a chloro-2-methyl- propane to toluene molar ratio of 0.5. Under the suitable reaction conditions, a 98% conversion of chloro-2-methylpropane and an 82.5% selectivity of PTBT were obtained. Ionic liquids could be reused 5 times with its catalytic activity unchanged, and the regenerated ionic liquids can be recycled.展开更多
Triphenylphosphine coupled with trichloroacetamide was determined to be an effective reagent for the conversion of 2,3,4,6-tetra-O-benzyl-D-glucopyranose as a glycosyl hemiacetal to the corresponding glycosyl chloride...Triphenylphosphine coupled with trichloroacetamide was determined to be an effective reagent for the conversion of 2,3,4,6-tetra-O-benzyl-D-glucopyranose as a glycosyl hemiacetal to the corresponding glycosyl chloride in excellent yield under mild and neutral conditions. Subsequently, the glycosyl chloride was reacted with alcohol or glycosyl acceptors in the presence of zinc（ll） bromide and molecular sieve 5 A to afford the corresponding glycosides in high yields and a-selectivity. This practical and convenient protocol can be utilized for the one-pot glycosylation of glycosyl hemiacetals.展开更多
基金the financial support from the Beijing University of Chemical Technologythe Key Laboratory of Advanced Chemical Engineering and Technology, Beijing Institute of Petrochemical Technology, for the analysis of samples
文摘Alkylation of toluene With 2-chloro-2-methylpropane （t-Bu-C1） to synthesize para-tert-butyltoluene （PTBT） was carded out in the presence of triethylamine hydrochloride-aluminum chloride ionic liquids used as the catalyst. The ionic liquids were prepared with different molar ratios of Et3NHC1 to A1CI3, and the effect of the molar ratio between A1C13 and Et3NHC1, the reaction time, the reaction temperature, the ionic liquid dosage, as well as the molar ratio of toluene to chloro- 2-methylpropane on the alkylation reaction of toluene with chloro-2-methyl-propane was investigated. The test results showed that the acidic ionic liquids prepared with Et3NHC1 and A1C13 had good activity and selectivity for the alkylation reaction of toluene with alkyl chloride to produce PTBT. The optimal reaction conditions were specified at an A1C13 to Et3N- HCI ratio of 1.6, a reaction temperature of 20 ℃, a mass fraction of toluene to ionic liquid of 10%, and a chloro-2-methyl- propane to toluene molar ratio of 0.5. Under the suitable reaction conditions, a 98% conversion of chloro-2-methylpropane and an 82.5% selectivity of PTBT were obtained. Ionic liquids could be reused 5 times with its catalytic activity unchanged, and the regenerated ionic liquids can be recycled.
文摘Triphenylphosphine coupled with trichloroacetamide was determined to be an effective reagent for the conversion of 2,3,4,6-tetra-O-benzyl-D-glucopyranose as a glycosyl hemiacetal to the corresponding glycosyl chloride in excellent yield under mild and neutral conditions. Subsequently, the glycosyl chloride was reacted with alcohol or glycosyl acceptors in the presence of zinc（ll） bromide and molecular sieve 5 A to afford the corresponding glycosides in high yields and a-selectivity. This practical and convenient protocol can be utilized for the one-pot glycosylation of glycosyl hemiacetals.
