A novel magnetic lignin composite removes Cr(vi).

In the present work, the influence of organic solvent on the mechanism of 5-hydroxymethylfurfural (HMF) preparation from glucose over CrCl 3 and the role of Brønsted acid (N-methyl-2-pyrrolidone hydrogen sulfate ([NMP]HSO 4 ), N-methyl-2-pyrrolidone bromide ([NMP]Br), N-methyl-2-pyrrolidone chlorine ([NMP]Cl), H 2 SO 4 , HBr and HCl) during the reaction were researched by a complementary computational and experimental study. It was found that dimethyl sulfoxide (DMSO) gave the lowest conversion of glucose by surrounding CrCl 3 , forming a six-coordinated structure (CrCl 3 -3DMSO). Glucose conversion in N,N-dimethylformamide (DMF) was not selective. N,N-Dimethylacetamide (DMA) and n-butyl alcohol exhibited superior selectivity towards HMF from glucose. Then the role of different Brønsted acids in DMA was expounded. On increasing the dosage of [NMP]HSO 4 , glucose conversion decreased. A computational study found that HSO 4 À could also combine with CrCl 3 , forming six-coordinate complexes. Addition of [NMP]Br and [NMP]Cl accelerated the generation of HMF significantly but didn't increase the yield. An experimental method preliminarily confirmed that they were mainly responsible for fructose dehydration to HMF. A subsequent computational study further verified that the two kinds of ILs had no effect on glucose isomerization.Scheme 1 Mechanism of glucose isomerization to fructose catalyzed by Cr 3+ complex in DMA ([Cr 3+ ] represents different complexes of Cr 3+ and anions or DMA).This journal is

This work prepared a series of novel assembled sulfated zirconia nanoparticle catalysts which were first applied in carbohydrate conversion.