Papers by Keyword: Lewis Acid

Abstract: 5-hydroxymethylfurfural (5-HMF) was produced from chitosan by a simple one-pot reaction including hydrolysis and dehydration in the presence of various ionic liquids and Lewis acids. Optimization of the reaction parameters including the screening of different catalysts, the effects of reaction time, temperature was investigated. The optimal reaction conditions are found to be 5 wt.% 1-butyl-3-methylimidazolium hydrogen sulfate ([BMIM][HSO4] ) aqueous solution and 100 mol% AlCl3•6H2O as cooperating catalyst, at 180 °C for 5 h under hydrothermal condition. HMF can be obtained in 25.2 % yield. More importantly, the catalysts can be recycled and exhibited constant activity for 5 successive trials.

Abstract: The reactions of aniline with CO₂ and CS₂ were investigated in the presence of sublimed AlCl₃ under the mild conditions (room temperature and ambient atmosphere). Reasonable mechanism, electrophilic substitution of carbonium and nitronium, was also provided according to GC/MS analysis of the reaction products. The resulting N,N-diphenylurea (DPU, high selectivity of 92.5mol%) and N,N-diphenyl thiourea (DPTU, high yield and selectivity of 80.1mol% and 99.7mol%, respectively) were purified by recrystallizing from ethanol and identified by melting point, element analysis, GC/MS, FTIR, UV and ¹H NMR data.

Abstract: N,N-alkylidene bisamides were synthesized with good to excellent yields from aliphatic or aromatic aldehydes and amides in the presence of 2 mol % of anhydrous zinc chloride. The synthesis successfully employed Lewis acid as catalyst.

Abstract: The development of a novel synthesis of acetophenone benzopyran is reported. A acetophenone benzopyran derivative was prepared from 1-(2,4-dihydroxyphenyl)ethanone (3) through O-prenylation and Lewis acids catalyzed intermolecular cyclization reaction. The structure of product 1-(3,4-dihydro-4,4-dimethyl-7-hydroxy-2H-1- benzopyran -6-yl)- ethanone (1) was characterized by UV, IR, 1H-NMR, 13C-NMR and elemental analysis.