Yongqin Qi

Graphene oxide as a facile acid catalyst for the one-pot conversion of carbohydrates into 5-ethoxymethylfurfural

Graphene oxide obtained by the Hummers method was discovered to be an efficient and recyclable acid catalyst for the conversion of fructose-based biopolymers into 5-ethoxymethylfurfural (EMF). EMF yields of 92%, 71%, 34% and 66% were achieved when 5-hydroxymethylfurfural (HMF), fructose, sucrose and inulin were used as starting materials, respectively.

Efficient catalytic system for the conversion of fructose into 5-ethoxymethylfurfural

DMSO can improve the selectivity of 5-hydroxymethylfurfural (HMF) in the conversion of carbohydrates. However, one of the bottlenecks in its application is product separation. Thus a one-pot synthesis of 5-ethoxymethylfurfural (EMF) rather than HMF from fructose in ethanol-DMSO was investigated. Phosphotungstic acid was used as an effective catalyst. The yield of EMF can be reached as high as 64% in the mixed solvent system of DMSO and ethanol within 130 min at 140 °C. Ethyl levulinate (LAE) was detected as the main by-product, the yield of which increased with the reaction time, temperature and the amount of catalyst. In addition, the existence of water could significantly reduce the yield of EMF and increased the yield of LAE. Most importantly, it was discovered that EMF could be much more efficiently extracted from the reaction solvent system by some organic solvents than HMF.

Degradable polymers from ring-opening polymerization of α-angelica lactone, a five-membered unsaturated lactone

A degradable polymer was prepared from α-angelica lactone, a five-membered unsaturated lactone, by ring-opening polymerization (ROP). The polymerizability of α-angelica lactone was explained by a DFT calculation. The degradability of the resultant polymer and the reaction kinetics of α-angelica lactone ROP were also considered. Owing to the presence of a CC bond in α-angelica lactone, the ROP of five-membered cyclic lactone becomes feasible under moderate conditions and the resultant polyester exhibits good degradability under light or acidic/basic circumstances. Since α-angelica lactone can be easily obtained from the commercially available green bio-platform chemical levulinic acid, its ROP may provide a potential route to produce functionalized aliphatic polyesters from renewable resources.

Efficient one-pot synthesis of deoxyfructosazine and fructosazine from D-glucosamine hydrochloride using a basic ionic liquid as a dual solvent-catalyst

An efficient one-pot dehydration process for convert D-glucosamine hydrochloride (GlcNH2) into 2-(D-arabino-1′,2′,3′,4′-tetrahydroxybutyl)-5-(D-erythro-2′′,3′′,4′′-trihydroxybutyl)pyrazine (deoxyfructosazine, DOF) and 2,5-bis-(D-arabino-1,2,3,4-tetrahydroxybutyl)pyrazine (fructosazine, FZ) was reported. A task-specific basic ionic liquid, 1-butyl-3-methylimidazolium hydroxide ([BMIM]OH), was employed as an environmentally-friendly solvent and catalyst. The products were qualitatively and quantitatively characterized by MALDI-TOF-MS, 1H NMR and 13C NMR spectroscopy. The influences of GlcNH2 concentrations, reaction temperature, reaction time, additives and co-solvents on the yields of products were studied. The maximum yield of 49% was obtained in the presence of [BMIM]OH and DMSO under optimized conditions (120 °C, 180 min). In addition, a plausible mechanism was proposed. Our project was to develop efficient, atom economical and eco-compatible routes for the synthesis of heterocyclic compounds from marine biomass (or nitrogen-containing biomass). The obtained aromatic heterocyclic compounds showed potential pharmacological action and physiological effects, and they also could be utilized as flavoring agents in the food industry.

Obtaining a high value branched bio-alkane from biomass-derived levulinic acid using RANEY® as hydrodeoxygenation catalyst

Compared to 5-HMF (C6H6O3), angelica lactone (C5H6O2) is a platform compound that has more potential for biomass-derived high performance bio-alkane fuel production due to a CC bond in the molecular structure, leading to a C–C coupling intermediate (C10 self-aggregation dimer) and higher C:O ratio (2.5), resulting in lower hydrogen consumption for the subsequent hydrodeoxygenation process. Biomass-derived levulinic acid was used as the only starting raw material to produce C10 branched alkanes. First, carboxyl and carbonyl functional groups of levulinic acid under catalysis via intramolecular esterification and dehydration yielded angelica lactone, which included two isomers of angelica lactone (α-angelica lactone and β-angelica lactone). Secondly, angelica lactone di/trimers would be obtained by angelica lactone self-aggregation: α-angelica lactone and β-angelica lactone connecting via C–C bond coupling. Finally, these intermediate products are selectively hydrodeoxygenated over a RANEY® catalyst to obtain C7–C10 branched alkanes. Nearly a 90% yield can be achieved under 483 K and 5 MPa H2 and the C10 branched alkane product, 3-ethyl-4-methyl heptane, accounts for 75% of the same.