Methods for synthesizing diethyl carbonate from ethanol and supercritical carbon dioxide by one-pot or two-step reactions in the presence of potassium carbonate

Carbon dioxide sequestration was studied by synthesizing diethyl carbonate (DEC) from ethanol and CO2 under supercritical conditions in the presence of potassium carbonate as a base. The co-reagent was ethyl iodide or a concentrated strong acid. This sequestration reaction occurs in two steps, which were studied separately and in a one-pot reaction. An organic-inorganic carbonate hybrid, potassium ethyl carbonate (PEC) is generated at the end of the first step. This intermediate was characterized and was found to be a target molecule for CO2 capture. Different co-reactants, such as ethyl iodide and concentrated strong Brönsted acid, were compared in the second step and used to investigate the reactivity of the hybrid. With ethyl iodide as the co-reactant, one-pot DEC synthesis gave higher yields (46%) than two-step production. The supercritical CO2 acts as a swelling solvent and compatibilizing agent in the reaction medium, favoring interactions between ethanol and CO2 and between PEC and ethyl iodide. The use of a phase transfer catalyst (PTC) increased DEC production (yield 51%) without increasing the amount of diethyl ether (DEE) produced as a by-product (yield 2%)

New perspectives of European oleochemistry / Les nouvelles perspectives de l’oléochimie européenne

INTRODUCTION : Of the many known and possible scenarios, this OCL dossier focuses on two trends likely to propel European oil chemistry into a strategic position in the short and long term (2020–2030), in the era of the bioeconomy

Conférence Chevreul

In this study two major strategy of transformation of the vegetables substrate are exposed. The first approach is related to the study of the catalytic heterocyclisation of natural glycerin in the glycerol carbonate. The system glycerol/glycerol carbonate constitutes a reactional medium of synthon generation and chemical compounds with skelton of multipurpose glycerylic. Glycerol carbonate is a molecule of first generation of the glycerol, it is conceived in natural media as a new chemistry which makes it possible to reinject glycerol in existing or new industry from the orginal procedure by the way of chemical means. The second approach regards the oleaginous seeds, as substrate in vitro or as microreactor in vivo. This marks a technological breakage compared to the model and tradional process of prapartion of oleochemical bases. In this matter it seems possible to obtain the fatty acids, fatty esters, directly from the oleaginous seeds by interaction between lipids and functional enzymes. This quantitave experimental approach produces the free hydrophobic moity and guarantees the multifonctionnal oleophiles compounds from the renewable oleochemistry

Stabilization of Curcumin by Complexation with Divalent Cations in Glycerol/Water System

The purpose of present study was to stabilize curcumin food pigment by its complexation with divalent ions like (Zn2+, Cu2+, Mg2+, Se2+), in “green media” and evaluate its stability in vitro compared to curcumin alone. The curcumin complexes were prepared by mechanical mixture of curcumin and sulfate salts of each metal (metal : curcumin 1/1mol) into unconventional and nontoxic glycerol/water solvent. Two stoichiometry of complex were obtained, 1 : 1 and 1 : 2 (metal/curcumin), respectively. On evaluation of in vitro stability, all complexes were found to provide a higher stability from curcumin alone

Synthèse et caractérisation de polyhydroxyuréthanes

Des nouvelles voies de synthèse sont proposées pour la préparation des hydroxyuréthanes et polyhydroxyuréthanes glycériliques, sans isocyanate, à partir de composés biosourcés fournisseurs de groupements cyclocarbonates hautement réactifs vis-à-vis des amines, diamines, polyamines. Les fournisseurs de groupement cyclocarbonate sont le carbonate de glycérol et le nouveau synthoon bifonctionnel l acrylate de carbonate de glycérol. Des hydroxyuréthanes ou polyhydroxyuréthanes glycéryliques polyoxygénés et polyazotés ont été ainsi élaborés via ces nouveaux intermédiaires cyclocarbonates glycériliques en substitution des carbonates cycliques d origine fossile comme les carbonates d alkylènes. La stratégie d élaboration des polyhydroxyuréthanes glycériliques à haut poids moléculaire s appuie sur la réactivité séquencée de l acrylate de carbonate de glycérol : réaction d Aza-Michaël sur le groupement éthylénique de l acrylate et réaction d aminolyse par ouverture de cycles carbonates à 5- chaînons. Selon la nature des polyamines, on prépare des polymères de poids moléculaire supérieur à 40000 g/mol, d aspects gel, mousse ou résine selon que les pontages linéaires ou interchaînes prédominent. Des réseaux chimiques intramoléculaires sont constitués par l établissement des liaisons hydrogène entre les sites O-H ou N-H et l oxygène du groupement carbamoyle du squelette glycérilique avec comme conséquence la réduction de la susceptibilité du groupe carbamoyle à l hydrolyse et l amélioration des propriétés de résistance chimique et mécanique des polyhydroxyuréthanes glycériliques.New synthesis routes have been developed for the preparation of glycerilic hydroxyurethanes and polyhydroxyurethanes without the use of isocyanates. They were prepared from biosourced cyclocarbonates, highly reactive towards amines, diamines and polyamines. The providers of cyclocarbonate function are glycerol carbonate and glycerol acrylate carbonate which is a bifunctional reactive. Glycerilic hydroxyurethanes and polyhydroxyurethanes with high oxygenated and nitrogenated potential were then designed via these new glycerilic cyclocarbonates intermediates, substitutes of fossil cyclic carbonates such as ethylene or propylene carbonates. The strategy development of high molecular weights glycerilic polyhydroxyurethanes is based on the sequenced reactivity of the glycerol acrylate carbonate: Aza-Michaël reaction on the ethylenic function of the acrylate and aminolysis reaction of the 5-membered cyclic carbonate function. According to the nature of the amine, polyhydroxyurethanes up to 40,000 g/mol were obtained. They can be obtained as foams, gels, resins, depending on the predominance of linear or cross-linked bridges. Intramolecular chemical networks were elaborated by hydrogen bonding between O-H or N-H sites with the oxygen atom of the carbamoyl function of the glycerilic skeleton. That is the reason why carbamoyle functions are less susceptible to hydrolysis and why the chemical and mechanical resistance properties of the glycerilic polyhydroxyurethanes are increased.TOULOUSE-INP (315552154) / SudocSudocFranceF

Tetraploid Wheats: Valuable Source of Phytosterols and Phytostanols

Phytosterols are known as healthy compounds obtained mainly from oilseed crops. Cereals were also studied for their sterols content. Few insights have been devoted to other tetraploid species than emmer and durum wheats. This work examined phytosterol and phytostanol content in seed of six tetraploid wheat species cultivated during two successive years under rainfed organic conditions in Auch (near Toulouse, France). Sterols (free and esterified sterols) were measured by gas-chromatography-flame ionisation detector. Mean value of sterols + stanols content was 99.5 mg 100 g−1 DW. The main sterol was β-sitosterol. Results showed a year effect on sterol content, whatever the wheat species. This could be explained by the differences in climatic conditions prevailing during plant cycle and grain filling. A large variability for sterols content was found between species and within each species. Emmer wheat revealed the lowest values for all sterols and stanols. Higher values of sterols were obtained in durum wheat. This work is the first report studying T. carthlicum, T. polonicum, T. turgidum, T. timopheevi. These species exhibited intermediate values of sterol contents between emmer and durum wheats. Wheat tetraploid species showed interesting levels of sterols and could serve as a great source of these healthy compounds mainly in Mediterranean region where they are consumed as wholegrain. Variation in climatic conditions could help to manage the level of these secondary metabolites

Effects of Cyclohexane/Acetone Ratio on Bixin Extraction Yield by Accelerated Solvent Extraction Method

In this study, accelerated solvent extraction (ASE) was applied to the quantitative extraction of bixin. The effects of cyclohexane/acetone ratios on bixin extraction yield were evaluated. Acetone was used in the process of pigment extraction and also played a major role in its analysis by UV-Vis spectrophotometry. Pure cis-bixin isolated by flash chromatography and characterized by Fourier Transform Infra Red spectrometry was used as a bixin standard for qualitative and quantitative analysis of annatto extracts which were obtained by accelerated solvents extraction. UV-Vis spectrophotometry analysis shows that the extraction using 100% cyclohexane gives the lowest bixin yield. This is different from the UV-Vis spectra generated with acetone extraction. The difference in percentage of acetone shows significant effects on bixin extraction yields. The use of cyclohexane:acetone (60%: 40%) solution at 50°C for 5min heating time results the highest total bixin extraction yield (48.00%) as compared to the other solvent ratios, and to the usual extraction methods using the same solvent (29.14%). High pressure liquid chromatography analysis shows that bixin extracted by this method has purity degree of 68.16%

Synthesis and properties of lipoamino acid/fatty acid mixtures. Influence of the amphiphilic structure.

The acylation of amino acids by acid chlorides with from 8 to 12 carbon atoms, in alkaline aqueous medium following Shotten-Baumann reaction, results in sodium salts of Nα-acylamino acids and fatty acids mixture. These lastest are present in proportion from 40 to 60%. These compositions represent mixtures of amphiphilic anionic surfactants. They contribute together to the properties of the formulation. Measurements of the surface-active properties of these formulations, such as critical micelle concentration (CMC), surface tension at the CMC (TS), foaming capacity (FC) and foaming stability (FS), show that surfactant mixtures with the longest chain have the most desirable properties. They are comparable to commercial petroleum-based surfactants. Thus, the CMC, TS and CM values of the formulation obtained starting from leucine and dodecanoyl chloride (310 mg/L, 30.1 mN/m and 200%, respectively) are similar, even better than, sodium dodecylsulfate (290 mg/L, 39.1 mN/m and 230%, respectively

Synthesis of new diesters of 1,4:3,6-dianhydro-d-glucitol by esterification with fatty acid chlorides

International audienceA new series of esters was prepared by esterification of 1,4:3,6-dianhydro-o-glucitol with long chain fatty acid chlorides. The experimental conditions prevented thermal degradation of the sugar and led to diesters with a high degree of purity. The final products were readily isolated and characterized by IR and NMR. Molecular modelling confirmed that the exo and endo configurations of the o-alkyl groups of the diesters of isosorbide were retained. This work reports a novel synthesis of diesters of natural origin which shows promise in environmentally sensitive applications, such as phytosanitory adjuvants, requiring biodegradable materials as replacements for fossil-derived products

Effects of genotype and sowing date on phytostanol-phytosterol content and agronomic traits in wheat under organic agriculture

Cereals are an important source of sterols and stanols in the human diet. The present study underlines the effect of genotype and weather conditions in bread wheat, on total sterol and stanol content (TSS), agronomic traits, proteins and ash content under organic conditions. Variations in TSS as well as other characters between two sowing dates were observed. A broad genotypic variability was also reported since extreme genotypes differed by more than 30 mg 100. g-1 DW for TSS, with total stanol content varying twofold. Moreover, two groups of genotypes that differed in agronomic production, ash and protein content were depicted, based on their response to an increase in temperature. This result suggests that the genotypic factor prevails over the sowing date factor for determining sterol and stanol traits in wheat cultivated under organic conditions. Nevertheless, a strong interaction exists between the two factors, which can be used to drive bioaccumulation of these molecules