Dehydration of xylose to furfural over niobium phosphate catalyst in biphasic solvent system

Phosphoric acid treated niobic acid(NbP)was used for the dehydration of xylose to furfural in biphasic solvent system,which was found to exhibit the best performance among the tested catalysts.The excellent performance of NbP could be explained by the better synergistic cooperation between Bro¨nsted and Lewis acid sites.Moreover,NbP showed good stability and no obvious deactivation or leaching of Nb could be observed after six continuous recycles.

Process optimization and mechanism study of ionic liquid-based mixed amine biphasic solvents for CO_(2) capture in biogas upgrading procedure

This study focused on enhancing the efficiency of methane upgrading and reducing energy consumption in the biogas upgrading process through the use of biphasic solvents.An aqueous-based biphasic solvent,comprising methyl monoethanolamine(MMEA),N-methyldiethanolamine(MDEA),and 1-butyl-3-methylimidazolium tetrafluoroborate(ItFB),was meticulously prepared.The biogas upgrading effect,regeneration efficiency,regeneration energy consumption,economic viability,selectivity,and phase separation characteristics of this absorbent were systematically analyzed.Various parameters,including different inlet flow rates,stirring rate,methane inlet concentrations,reaction temperatures,and amine mixing ratios,were adjusted to investigate their impact.A comprehensive evaluation was conducted on the biogas upgrading effect and substance migration trends of the biphasic solvent.Optimal process parameters were determined,demonstrating the favorable impact of the biphasic solvent on biogas upgrading.The upgraded gas achieved a methane purity exceeding 96%,and the regeneration energy consumption decreased by 44.27% compared to 30 wt.%MEA,resulting in a more than 50% improvement in economic efficiency.The interaction between the ionic liquid and carbamate facilitated the phase separation process,with carbon enrichment after separation exceeding 95%.This enhancement significantly contributed to the improvement of regeneration energy consumption.The study thus concludes that biphasic solvents,exemplified by the described aqueous-based solution,offer a promising avenue for effective biogas upgrading with notable advancements in economic and energy efficiency.

Asymmetric Synthesis of (-)-1-Trimethylsilyl-ethanol with Immobilized Saccharomyces Cerevisiae Cells in Water/Organic Solvent Diphasic System

Asymmetric synthesis of (-)-1-trimethylsilyl-ethanol with immobilized Saccharomyces cerevisiae cells in water/organic solvent biphasic system was studied. The effects of shake speed, hydrophobicity of organic solvent, volume ratio of water phase to organic phase, pH value of aqueous phase and reaction temperature on the initial reaction rate, maximum yield and enantiomeric excess (ee) of the product were systematically explored. All the above-mentioned factors had significant influence on the reaction. n-Hexane was found to be the best organic solvent for the reaction. The optimum shake speed, volume ratio of water phase to organic phase, pH value and reaction temperature were 150 r.min-1, 1/2, 8 and 30 ℃ respectively, under which the maximum yield and enantiomeric excess of the product were as high as 96.8% and 95.7%, which are 15% and 16% higher than those of the corresponding reaction performed in aqueous phase. To our best knowledge, this is the most satisfactory result obtained.

Asymmetric Reduction of 3,5-Bistrifluoromethyl Acetophenone with NADH Regeneration by Immobilized Cells of Saccharomyces rhodotorula in Aqueous-Organic Solvent Biphasic System

Asymmetric reduction of 3,5-bistrifluoromethyl acetophenone to produce(S)-3,5-bistrifluoromethylphenyl ethanol was successfully carried out with sodium alginate immobilized Saccharomyces rhodotorula cells in an aqueous-organic solvent biphasic system.The possible influential factors were examined thoroughly according to their effects on conversion rate and e.e of the product.Organic solvents were rated by their biocompatibility and conversion potential.The immobilized cells [125 mg/mL in 20 mmol/L Tris-HCl buffer and 5%(j) octane at pH 8] showed the best conversion with a substrate concentration of 1.42 g/L at 30℃ with glucose as co-substrate for cofactor regeneration.Sequential 8-batch process was carried out with immobilized cells with a slow decrease in conversion and e.e.The immobilized cells showed stable catalytic activity with 50% reserved activity and are superior especially in reusability in comparison with resting cells.