The condensation of glycerol, a platform chemical from renewable materials, with benzaldehyde to generate cyclic acetals was investigated using acidic ionic liquid as catalyst. Evidence was presented that the product mixture of 4-hydroxymethyl-2-phenyl-1,3-dioxolane and 5-hydroxyl-2-phenyl-1,3-dioxane, with cis and trans two stereo-isomers for each one identified by 1H NMR were obtained. Further modification of reaction conditions promoted by N-butyl-pyridinium bisulfate ([BPy]HSO4) led to the totally cyclic acetals with 99.8% yield at room temperature. A micro water-removal reactor constituted by ionic liquids was proposed, which favourably shifted the condensation equilibrium to the product side by transferring the produced water out of the organic phase in time, so that the water-carrying agent or reactive distillation was avoided. Moreover, the product separation made this methodology more accessible to sustainable green biomass chemistry.

•InCl3 presented a remarkable catalytic effect on the dehydration of monosaccharides into 5-HMF and LA.•Fructose has the faster conversion to 5-HMF, and relatively more LA was obtained using glucose.•The isomerization from glucose to fructose was easier than the reversible process.Indium trichloride (InCl3) was used as catalyst for the conversion of monosaccharides into 5-hydroxymethylfurfural (5-HMF) and levulinic acid (LA) in aqueous medium. 5-HMF yield of 60% (10 min) and LA yield of 57% (60 min) were achieved from glucose at 180 °C with 2.5 mol% of InCl3, and 5-HMF yield of 79% (15 min) and LA yield of 45% (60 min) were obtained from fructose under the same conditions. Moreover, the isomerization process between glucose and fructose was investigated through the comparative studies of glucose/fructose mixture with different ratios as substrates. It was found that InCl3 could not only catalyze the isomerization of glucose to fructose as well as the reverse direction, but also have the positive effects on the dehydration and conversion of monosaccharides. Based on this, a catalytic mechanism of dehydration of glucose and fructose promoted by InCl3 was proposed.

In the present study, the transesterification of glycerol trioleate was carried out over a basic ionic liquid, 1-butyl-3-methylimidazolium hydroxide ([Bmim]OH) and an 87.2% yield of methyl ester was achieved. The product was isolated through simple decantation from the biphasic system due to the immiscibility of [Bmim]OH with ester. [Bmim]OH can be easily recovered and reused six times without dramatic decrease in ester yield.

Sulfamic acid has been proved to be the most efficient and recyclable catalyst in carbamate synthesis from alkylamine and dialkyl carbonate. High selectivity, cost-efficiency and simple product separation were the advantageous features obtained in this process. Sulfamic acid could be reused several times and keep its initial activity in the recycle runs. In addition, sulfamic acid has also exhibited the potential catalytic ability for alkylation of aromatic amines.