Polar aprotic solvent-water mixture as the medium for catalytic production of hydroxymethylfurfural (HMF) from bread waste

Valorisation of bread waste for hydroxymethylfurfural (HMF) synthesis was examined in dimethyl sulfoxide (DMSO)-, tetrahydrofuran (THF)-, acetonitrile (ACN)-, and acetone-water (1:1v/v), under heating at 140°C with SnCl4 as the catalyst. The overall rate of the process was the fastest in ACN/H2O and acetone/H2O, followed by DMSO/H2O and THF/H2O due to the rate-limiting glucose isomerisation. However, the formation of levulinic acid (via rehydration) and humins (via polymerisation) was more significant in ACN/H2O and acetone/H2O. The constant HMF maxima (26-27mol%) in ACN/H2O, acetone/H2O, and DMSO/H2O indicated that the rates of desirable reactions (starch hydrolysis, glucose isomerisation, and fructose dehydration) relative to undesirable pathways (HMF rehydration and polymerisation) were comparable among these mediums. They also demonstrated higher selectivity towards HMF production over the side reactions than THF/H2O. This study differentiated the effects of polar aprotic solvent-water mediums on simultaneous pathways during biomass conversion

A systematic review of randomised controlled trials assessing effectiveness of prosthetic and orthotic interventions.

BACKGROUND: Assistive products are items which allow older people and people with disabilities to be able to live a healthy, productive and dignified life. It has been estimated that approximately 1.5% of the world's population need a prosthesis or orthosis. OBJECTIVE: The objective of this study was to systematically identify and review the evidence from randomized controlled trials assessing effectiveness and cost-effectiveness of prosthetic and orthotic interventions. METHODS: Literature searches, completed in September 2015, were carried out in fourteen databases between years 1995 and 2015. The search results were independently screened by two reviewers. For the purpose of this manuscript, only randomized controlled trials which examined interventions using orthotic or prosthetic devices were selected for data extraction and synthesis. RESULTS: A total of 342 randomised controlled trials were identified (319 English language and 23 non-English language). Only 4 of these randomised controlled trials examined prosthetic interventions and the rest examined orthotic interventions. These orthotic interventions were categorised based on the medical conditions/injuries of the participants. From these studies, this review focused on the medical condition/injuries with the highest number of randomised controlled trials (osteoarthritis, fracture, stroke, carpal tunnel syndrome, plantar fasciitis, anterior cruciate ligament, diabetic foot, rheumatoid and juvenile idiopathic arthritis, ankle sprain, cerebral palsy, lateral epicondylitis and low back pain). The included articles were assessed for risk of bias using the Cochrane Risk of Bias tool. Details of the clinical population examined, the type of orthotic/prosthetic intervention, the comparator/s and the outcome measures were extracted. Effect sizes and odds ratios were calculated for all outcome measures, where possible. CONCLUSIONS: At present, for prosthetic and orthotic interventions, the scientific literature does not provide sufficient high quality research to allow strong conclusions on their effectiveness and cost-effectiveness

Activation of microcrystalline cellulose in a CO2-based switchable system

International audienc

Synthesis of functionalized tetrahydrofuran derivatives from 2,5-dimethylfuran through cascade reactions

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Elucidation of the role of betaine hydrochloride in glycerol esterification: towards bio-based ionic building blocks

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Carbon dioxide as a traceless caramelization promotor: preparation of prebiotic difructose dianhydrides (DFAs)-enriched caramels from d -Fructose

Activation of a concentrated solution of d-fructose with carbonic acid, generated from carbon dioxide, induces the formation of difructose dianhydrides (DFAs) and their glycosylated derivatives (glycosyl-DFAs), a family of prebiotic oligosaccharides. Under optimized conditions, up to 70% of the active DFA species were obtained from a highly concentrated solution of fructose, avoiding the filtration step and contamination risk associated with the current procedures that employ heterogeneous catalysis with acid ion-exchange resins. The optimized CO-promoted preparation of DFA-enriched caramel described here has been already successfully scaled up to 150 kg of d-fructose for nutritional studies, showing that implementation of this process is possible at a larger scale

Conversion of wheat straw to furfural and levulinic acid in a concentrated aqueous solution of betaine hydrochloride

International audienceGlycine betaine hydrochloride (BHC), a safe acid industrially produced from the largely available glycine betaine isolated from the manufacture of sugar from beet, was used in combination with water to produce sustainable reaction media capable of selectively converting agricultural wastes to furfural and levulinic acid. At the end of the process, BHC can be conveniently recovered and recycled. Under optimized conditions, furfural was produced with 65% and 73% yield from wheat straw and xylan originated from beechwood, respectively. More importantly, by closely controlling the reaction temperature, it was possible to selectively drive the reaction either to xylose, furfural or levulinic acid. This process based on the use of biodegradable and safe BHC opens a sustainable route for the production of valuable fine chemicals from lignocellulosic biomass

Homogeneously-acid catalyzed oligomerization of glycerol

Here we report the screening of various homogeneous acid catalysts in the oligomerization of glycerol at 150 degrees C. Under optimized conditions, a mixture of oligoglycerol with an average degree of oligomerization of 3.4 was obtained at a glycerol conversion of 80%. At such a conversion, the selectivity to oligoglycerols was higher than 90%. Oligoglycerols were then successfully alkylated, offering an attractive route to valuable molecules (biosurfactants or hydrotropes)

Impact of shaping Aquivion PFSA on its catalytic performances

Over the last three years, a growing amount of reports highlighted the exceptional catalytic performances of Aquivion PFSA in many challenging chemical reactions. To date, all these studies employed Aquivion PFSA in powder form and the impact of shaping Aquivion PFSA on its catalytic performances has never been reported, although this aspect is of prime importance for implementation on a larger scale. Often considered as a matter of practical interest in the current literature, the shaping of a catalyst is actually mandatory and is clearly a key research topic for catalyst design and chemical engineering. Here, we explored the effect of shaping Aquivion PFSA on (1) its catalytic performances (i.e. yield, reaction rate and space time yield), (2) its ease of recovery at the end of the reaction (i.e. filtration, recyclability) and (3) its deactivation rate. In particular, we found that shaping Aquivion PFSA into micropellets was a good compromise (between powder and macropellets) to maintain acceptable catalytic performances while considerably facilitating the recovery of Aquivion PFSA at the end of the reaction. Last but not least, by properly controlling the reaction conditions, it was possible to limit the deactivation of Aquivion PFSA shaped into micropellets, a recurrent problem in catalytic carbohydrate processing. © 2019 The Royal Society of Chemistry