Simple and efficient furfural production from xylose in media containing 1-Butyl-3-Methylimidazolium hydrogen sulfate

The acidic 1-butyl-3-methylimidazolium hydrogen sulfate ([bmim][HSO4]) ionic liquid was explored as both a reaction medium and a catalyst in the furfural production from xylose. Preliminary experiments were carried out at 100–140 °C for 15–480 min in systems containing just xylose dissolved in [bmim][HSO4] in the absence of externally added catalysts. More than 95% xylose conversion was achieved when operating at 120 or 140 °C for 300 and 90 min, respectively; but just 36.7% of the initial xylose was converted to furfural. Operation in biphasic reaction systems (in the presence of toluene, methyl-isobutyl ketone or dioxane as extraction solvents) at 140 °C under selected conditions resulted in improved furfural production (73.8%, 80.3%, and 82.2% xylose conversion to furfural for the cited extraction solvents, respectively)

Effect of hydrothermal pretreatment for fermentable sugars production using brown macroalgae as raw material

Energy high demands and concerns about global climate changes have led to the resurgence of biofuels as bioethanol. The conversion of biomass (macroalgae) into high added-value chemicals (pigments, food supplements, polymers, surfactants and fertilizer) and bioenergy renewable products as bioethanol is essential in order to sustain our present and future. The polysaccharides conversion from macroalgae to fermentable sugars and fuel ethanol production is still to be studied. For that reason, the aim of this work was to evaluate the production of fermentable sugars from brown macroalgae using hydrothermal pretreatment that it is considered an environmentally friendly process. The hydrothermal pretreatment was evaluated in different conditions of time and temperature. The best operating condition for the production of fermentable sugars was at 200 ºC for 30 min, obtaining 0.41 g of total sugars/ g of macroalgae, dry basis. The hydrothermal process proved to be a promising pretreatment to produce fermentable sugars

Glycine-betaine-derived ionic liquids: Synthesis, characterization and ecotoxicological evaluation

Ionic Liquids (ILs) are generically regarded as environmentally "harmless" and thus, assumed as "non-toxic". However, due to the endless design possibilities, their ecotoxicological profile is still poorly known. An accurate knowledge on the toxicity of a substance is required, under the scope of environmental regulation worldwide, before their application and commercialization. Knowledge on the relationship between the chemical structure and toxic effects is essential for the future design of more biocompatible solvents. Focusing on the use of ILs as base lubricants, lubricant additives, or even as potential working fluids for absorption heat pumps, the knowledge on its environmental impact is of great importance, due to the possibility of spills. In this specific context, four analogues of glycine-betaine-based ILs (AGB-ILs) and four glycine-betaine based ILs (GB-ILs) were synthesized and characterized. Their ecotoxicity was assessed using representatives of two trophic levels in aquatic ecosystems, the bacteria Allivibrio fischeri (commonly used as a screening test organism) and the microalgae Raphidocelis subcapitata (as an alternative test organism that has been proven very sensitive to several IL families). The microalgae were more sensitive than the bacteria, hence, following a precautionary principle, we recommend considering the toxicity towards microalgae as an indicator in future studies regarding the focused ILs. Although four of the studied ILs were derived from a natural amino acid, all were considered hazardous for the aquatic environment, disproving the primary theory that all ILs derived from natural compounds are benign. Furthermore, the modification in the structure of anion and the cation can lead to the increase of toxicity.publishe

Synthesis, microstructure and volumetry of novel metal thiocyanate ionic liquids with [BMIM] cation

We present a new family of ionic liquids (ILs) with a common cation, 1-butyl-3-methyl imidazolium, the popular [BMIM]+ (also written C4C1Im+) and a variety of anionic complexes (also called adducts) based in thiocyanate (SCN)?: one blank compound, BMIM(SCN), and ten doped with metals having different oxidation states: Al+3, Mn+2, Fe+3, Cr+3, Ni+2, Hg+2, Zn+2, Co+2, Cd+2 and Cu+, forming, respectively, [BMIM]3[Al(SCN)6], [BMIM]4 Mn(SCN)6, [BMIM]3 Fe(SCN)6, [BMIM]3 Cr(SCN)6, [BMIM]4 Ni(SCN)6, [BMIM]2 Hg(SCN)4, [BMIM]2 Zn(SCN)4, [BMIM]2 Co(SCN)4, [BMIM]2 Cd(SCN)4 and [BMIM]3 Cu(SCN)4. All of them were synthesized by us, except the blank IL and the Co thiocyanate, which are commercial. Obtained products have been characterized by NMR, and also by electrospray ionization, MS-ES, which allows the determination of the new ILs purities. Then, compounds have been analyzed using FT-IR and Raman spectroscopy. In addition, magnetic susceptibility and refractive index measurements were performed in some of the compounds studied, as well as thermal characterization using DSC and TGA. Finally, experimental measurements of density on all those ILs have been performed, and for some of the samples in a broad temperature range (about 100 K). In spite of being very similar compounds from the chemical point of view, they present quite different physical properties, including optical, thermal and magnetic ones? Also, they show different oxidation states (one with +1, six with +2 and other three with +3). We guess that this family of ILs will have interesting applications, mainly for photonic devices

Valorization, comparison and characterization of coconuts waste and cactus in a biorefinery context using NaClO2-C2H4O2 and sequential NaClO2-C2H4O2/autohydrolysis pretreatment

The search for new sources of lignocellulosic raw materials for the generation of energy and new compounds encourages the search for locations not well known and with a high potential for biomass availability as is the case of the Northeast Region of Brazil. Thus, the cactus (CAC), green coconut shell (GCS), mature coconut fibre and mature coconut shell were pretreated by NaClO2C2H4O2 and sequential NaClO2C2H4O2/autohydrolysis aiming at the obtention of high added-value compounds in the liquid fraction and solid phase. The yield of the solid phase was between 61.42 and 90.97% and the reduction up to 91.63% of lignin in the materials pretreated by NaClO2C2H4O2. After NaClO2C2H4O2/autohydrolysis pretreatment the obtained solids yield was between 43.57 and 52.08%, with a solubilization of the hemicellulose content up to 81.42%. For both pretreatments the cellulosic content remained almost unchanged. The pretreated solids were characterized by SEM, X-ray and crystallinity indexes showing significant modifications when submitted to pretreatments. These results were further confirmed by the enzymatic conversion yields of 81.6890.03 and 86.9790.36% of the LCMs pretreated by NaClO2C2H4O2 and pretreated by NaClO2C2H4O2/autohydrolysis, respectively. The resulting liquors had a total phenolic compounds content between 0.20 and 3.05 g/L, lignin recovered up to 7.40 g/L (absence of sulphur) and xylooligosaccharides between 16.13 and 20.37 g/L. Thus, these pretreatments showed an efficient fractionation of LCMs, especially in the GCS, being an important requirement for the generation of products and byproducts in the context of the biorefinery.The authors gratefully acknowledge the Brazilian research funding agencies CNPq and CAPES for financial support. Financial support from the Energy Sustainability Fund 2014-05 (CONACYT-SENER), Mexican Centre for Innovation in Bioenergy (CemieBio), Cluster of Bioalcohols (Ref. 249564) is gratefully acknowledged. We also gratefully acknowledge support for this research by the Mexican Science and Technology Council (CONACYT, Mexico) for the infrastructure project - INFR201601 (Ref. 269461) and CB-2015-01 (Ref. 254808).info:eu-repo/semantics/publishedVersio

Evaluation of appendicitis risk prediction models in adults with suspected appendicitis

Background Appendicitis is the most common general surgical emergency worldwide, but its diagnosis remains challenging. The aim of this study was to determine whether existing risk prediction models can reliably identify patients presenting to hospital in the UK with acute right iliac fossa (RIF) pain who are at low risk of appendicitis. Methods A systematic search was completed to identify all existing appendicitis risk prediction models. Models were validated using UK data from an international prospective cohort study that captured consecutive patients aged 16–45 years presenting to hospital with acute RIF in March to June 2017. The main outcome was best achievable model specificity (proportion of patients who did not have appendicitis correctly classified as low risk) whilst maintaining a failure rate below 5 per cent (proportion of patients identified as low risk who actually had appendicitis). Results Some 5345 patients across 154 UK hospitals were identified, of which two‐thirds (3613 of 5345, 67·6 per cent) were women. Women were more than twice as likely to undergo surgery with removal of a histologically normal appendix (272 of 964, 28·2 per cent) than men (120 of 993, 12·1 per cent) (relative risk 2·33, 95 per cent c.i. 1·92 to 2·84; P < 0·001). Of 15 validated risk prediction models, the Adult Appendicitis Score performed best (cut‐off score 8 or less, specificity 63·1 per cent, failure rate 3·7 per cent). The Appendicitis Inflammatory Response Score performed best for men (cut‐off score 2 or less, specificity 24·7 per cent, failure rate 2·4 per cent). Conclusion Women in the UK had a disproportionate risk of admission without surgical intervention and had high rates of normal appendicectomy. Risk prediction models to support shared decision‐making by identifying adults in the UK at low risk of appendicitis were identified

Is the Impact of Ethylammonium Nitrate on Soil Basal Respiration Modified by Addition of Aluminium Salt to Improve the Performance in Electrochemical Applications?

10 páginas, 5 tablas, 1 figuraInterest in the possible use of EAN in electronic devices has increased in recent years. EAN can be used directly as an electrolyte, but its application could potentially be optimized by mixing with a metal salt such as Al(NO3)3. Although ionic liquids (ILs) have been considered to cause little harm because they are non-volatile, they can have toxic effects on the terrestrial environment. In this study, the impact on soil basal respiration of EAN alone, a mixture of EAN and Al(NO3)3, and Al(NO3)3 alone was investigated using two soils with different organic matter contents. The Al(NO3)3 did not affect soil respiration in either soil, while EAN, either alone or mixed with Al(NO3)3 affected both soils.This research was financially supported by the Spanish MICINN through project CGL2015-66857-C2-1-R co-financed by the ERDF, and by the Xunta de Galicia through the RCG project IN607A 2017/06, the Contrato-Programa IIAG-Xunta 2021-2022, and the Galician Network project ED431D 2017/06. J. J. Parajó wishes to thank the I2C postdoctoral program of the Xunta de Galicia for support in funding the study. E. Priano is grateful for funding support from the Enhancing Mobility Between Latin-American and Caribbean Countries and Europe Program (Argentina-España, 2018)Peer reviewe