Conversion of Glucose to 5-Hydroxymethylfurfural in a Microreactor

Simultaneous production of carotenoids and chemical building blocks precursors from chlorophyta microalgae

Replacement of fossil fuels has to be accompanied by the incorporation of bio-based procedures for the production of fine chemicals. With this aim, the microalga Chlamydomonas reinhardtii was selected for its ability to accumulate starch, an environmentally-friendly alternative source of chemical building blocks, such as 5'-hydroxymethylfurfural or levulinic acid. The content of appreciated lipophilic coproducts was assessed in the selected microalga cultured at different nutritional conditions; and the parameters for the acidic hydrolysis of the algal biomass, obtained after pigments extraction, were optimized using a Central Composite Design. Response Surface Methodology predicted that the optimal hydrolysis conditions were elevated temperature, high DMSO % and short hydrolysis time for glucose. LA was favored at long times and high acid % and 5'-HMF at lower acid % and high DMSO %. Chlamydomonas can therefore be used as a sustainable feedstock for the simultaneous production of high-added value lipophilic compounds and platform chemicals.

Continuous hydrothermal furfural production from xylose in a microreactor with dual-acid catalysts

An effective continuous furfural production from xylose in a microreactor over dual-acid catalysts was proposed. In this work, furfural was synthesized in an organic solvent-free system using formic acid and aluminum chloride as catalyst. The role of these catalysts in the consecutive reactions was examined and verified. The influence of operating conditions including xylose concentration, reaction temperature, residence time, total catalyst concentration, and catalyst ratio on the yield of furfural was investigated and optimized. The furfural yield of 92.2% was achieved at the reaction temperature of 180 °C, residence time of 15 min, catalyst molar ratio of 1 : 1, xylose concentration of 1 g L⁻¹, and total catalyst concentration of 16 mM. The superior production performance of our process was highlighted in terms of the low catalyst concentration and short residence time compared to those of other systems based on the literature. In addition, a continuous in situ catalyst removal (purification) was demonstrated, providing further insights into the practical development of continuous furfural production.

An effective continuous furfural production from xylose in a microreactor over dual-acid catalysts was proposed. In this work, furfural was synthesized in an organic solvent-free system using formic acid and aluminum chloride as catalyst.

High-throughput monitoring of biomass conversion reaction with automatic time-resolved analysis

Reactions of biomass conversions are of great importance in fine chemistry for substantial development. While numerous studies have been performed to search for functional materials to catalyze biomass conversions, a robust and high-throughput analytical method is rather limited, which may hamper further integration and automation of the reactions. Here we propose an automatic and sequential method for the investigation of glucose conversion. By combining sequential sample injection and high-speed capillary electrophoresis (HSCE) techniques, we can monitor the glucose conversion from the beginning toward the end with a good temporal resolution. The HSCE assays are performed using short capillaries (effective length of 10 cm, i.d./o.d. of 50 μm/365 μm), and the analytes are separated at an electric field of 467 V/cm and are detected by UV-absorption at 200 nm with mixed 0.2 mM CTAB, 10 mM borate, 20 mM sorbic acid (pH 12.2) as the background electrolyte. All compounds involved in the reaction, including all products (fructose, 5-hydroxymethylfurfural, formic acid and levulinic acid) and the remaining substrate glucose, are efficiently separated and simultaneously detected from just one analysis with a temporal resolution of one minute. The method exhibits high-resolution separation, a wide linear range with limit-of-detection down to μg/mL-level, as well as excellent repeatability in sequential analysis. It is indicated that the proposed method is of great value in the analysis of complicated biomass conversion and could be potentially applied in various catalytic chemical reactions.

From circular synthesis to material manufacturing: advances, challenges, and future steps for using flow chemistry in novel application area

We review the emerging use of flow technologies for circular chemistry and material manufacturing, highlighting advances, challenges, and future directions.