One pot conversion of chitin into 3A5AF opens up a new avenue for renewable, value added N-containing chemicals.

A novel route has been developed that yields levulinic acid (4-oxopentanoic acid, LA) and 5-hydroxymethylfurfural (5-HMF) from chitosan. Hydrolysis of chitosan was performed in the presence of a range of Lewis acids with SnCl 4 ·5H 2 O providing the best results. All reactions were performed in sealed vessels under microwave irradiation at 200°C for 30 min. Typical pressures achieved were 17 to 19 bar. 23.9 wt% LA was produced from 100 mg chitosan using 0.24 mmol SnCl 4 ·5H 2 O and 4 mL water. Under more dilute conditions, 10.0 wt% 5-HMF was obtained using 0.12 mmol SnCl 4 ·5H 2 O and 15 mL water. We propose that under more concentrated reaction conditions the 5-HMF formed reacts further to produce LA. When chitin is treated similarly, no 5-HMF is produced but up to 12.7 wt% LA can be obtained. For comparison, 32.0 wt% LA was produced from 100 mg glucosamine hydrochloride using 0.26 mmol SnCl 4 ·5H 2 O and 20 mL water. This corresponds to a yield of 59.4%. The SnCl 4 forms SnO 2 and HCl in solution and under similar conditions using SnO 2 and HCl, chitosan formed 27.4 wt% LA.

Research into renewable chemicals, fuels and materials sourced from the oceans at Memorial University and elsewhere is employing green chemical technologies for the transformation of algae and food industry waste streams into useful products. A very small proportion of biomass utilization research is currently focused on these feedstocks and efforts focused in this area could reduce land space competition between food and chemical/fuel production. This perspective highlights some of the achievements and potential opportunities surrounding the use of algae and waste from shellfish and finfish processing. In particular, investigations in this field have used alternative solvents (water, supercritical carbon dioxide and methanol or ionic liquids) extensively. Supercritical Fluid Extraction (SFE) has been used to extract lipids and pigments from algae, and oils from fish-processing plant waste streams. Water can be used to isolate potentially high value biologically-active oligosaccharides from some seaweeds. Biotechnological approaches are showing promise in the separation of biopolymers from shellfish waste streams. Production of new nitrogen-containing bioplatform chemicals (e.g. 3-acetamido-5-acetylfuran) from aminocarbohydrates (chitin, chitosan and N-acetylglucosamine) is being pursued.

Research into renewable bioresources at York and elsewhere is demonstrating that by applying green chemical technologies to the transformation of typically low value and widely available biomass feedstocks, including wastes, we can build up new environmentally compatible and sustainable chemicals and materials industries for the 21st century. Current research includes the benign extraction of valuable secondary metabolites from agricultural co-products and other low value biomass, the conversion of nature's primary metabolites into speciality materials and into bioplatform molecules, as well as the green chemical transformations of those platform molecules. Key drivers for the adoption of biorefinery technologies will come from all stages in the chemical product lifecycle (reducing the use of non-renewable fossil resources, cleaner and safer chemical manufacturing, and legislative and consumer requirements for products), but also from the renewable energy industries (adding value to biofuels through the utilisation of the chemical value of by-products) and the food industries (realising the potential chemical value of wastes at all stages in the food product lifecycle).

In this mini-review, progress made in the use of ionic liquid catalysts and related systems for cycloaddition reactions of carbon dioxide with epoxides is described with the primary focus on results from the past eight years.