JournalTOCs

Comptes Rendus : Chimie
Journal Prestige (SJR): 0.438

Citation Impact (citeScore): 2
Number of Followers: 0

This is an Open Access Journal

Open Access journal
ISSN (Print) 1631-0748 - ISSN (Online) 1878-1543
Published by Académie des sciences

[7 journals]

Muhammad Yerizam; Asyeni Miftahul Jannah et al. - Bioethanol production
from coconut husk using DES-NADES pretreatment and enzymatic hydrolysis
method
- Abstract: Bioethanol is an alternative fuel produced during biomass fermentation. Among the available biomass resources for bioethanol production, coconut husk is an interesting raw material due to its high cellulose content. This study aims to evaluate the coconut husk conversion into bioethanol using DES (ChCl:MEA) and NADES (Be:La) solvents for the delignification process. The molar ratios of HBA and HBD of the two solvents were varied (1:4, 1:6, 1:8) at 2, 4, 6, and 8 h for each ratio. The delignified samples were hydrolyzed using the 5% (w/w) of cellulase enzymes and fermented for seven days using Saccharomyces cerevisiae. The results showed that DES (ChCl:MEA) and NADES (Be:La) could remove lignin at about 60.53% and 65.81%. The glucose content was obtained at 0.5% (brix) by both solvents and bioethanol content was obtained at 13.9% and 14% (v/v) for DES and NADES, respectively.
  PubDate: Thu, 16 Mar 2023 08:46:05 +000
α -pyridylamines+via+fluoroarenes&rft.title=Comptes+Rendus+:+Chimie&rft.issn=1631-0748&rft.date=2023&rft.volume=">Alessio Nicolini; Biagio Anderlini et al. - An efficient
transition-metal-free route to oligo- α -pyridylamines via fluoroarenes
- Abstract: The new polynucleating tripodal proligand H 6 tren(dpa) 3 , containing thirteen nitrogen donors of four different types, was designed, synthesized, and isolated in good yield (∼60%) via a transition-metal-free triple N-arylation of H 6 tren with HXdpa (X = Br or F), using K 2 CO 3 or Cs 2 CO 3 as a base (H 6 tren = tris(2-aminoethyl)amine, HXdpa = 6-halogeno-N-(pyridin-2-yl)pyridin-2-amine). HFdpa was prepared with excellent yield (90–92%) by reaction of 2,6-difluoropyridine with 2-aminopyridine in LiH/toluene/pyridine and was found more reactive than HBrdpa, affording higher conversion and higher yield. Use of Cs 2 CO 3 turned out to be essential for achieving high regioselectivity and eliminating overarylation almost completely.
  PubDate: Tue, 14 Mar 2023 09:39:03 +000
La+2+ O+3+ /
ZrO+2+ /
SiO+2+ +catalyst+systems&rft.title=Comptes+Rendus+:+Chimie&rft.issn=1631-0748&rft.date=2023&rft.volume=">Maxim Makhin; Stanislav Bedenko et al. - Investigations into the
conversion of ethanol to butadiene-1,3 using CuO/ La 2 O 3 / ZrO 2
/ SiO 2 catalyst systems

Abstract: Catalyst systems of the Lebedev reaction from oxides of Zn, Zr, La, Cu and silica gel were investigated. The catalysts were characterized by BET, XRF, XRD, TPD-NH 3 and TPR. The parameters of ethanol to butadiene-1,3 process were determined using ethanol, acetaldehyde and water as raw materials without inert diluents. When using a mixture of ethanol and acetaldehyde as a feedstock, the selectivity of the butadiene-1,3 formation exceeds 60% and its productivity is at least 0.32g BD ·g cat -1 ·h -1 . The average butadiene-1,3 yield was over 34% in 8 h. The stability of the CuO/La 2 O 3 /ZrO 2 /SiO 2 catalyst was evaluated for 5 cycles of 24 h. When using 96% ethanol, the butadiene-1,3 yield decreased from 25.1% to 13.8% during the full cycle. Oxidation regeneration of the catalyst makes it possible to completely restore its catalytic activity.
PubDate: Fri, 10 Mar 2023 14:30:15 +000
Iness Jabri Karoui; Majdi Hammami et al. - The use of D-Optimal Mixture
Design in the development of date stone and spirulina tablet formulation
as a phycocyanin dietary supplement
- Abstract: The aim of this work is in the formulation of a dietary supplement, combining spirulina and date stone benefits. For this, a study was done on these two ingredients by determining their approximate composition and antioxidant potential. Following this, we used a statistical method to determine the appropriate proportions of ingredients to obtain a tablet with optimal physical properties. After setting these parameters, we analysed this tablet’s composition and effectiveness by evaluating its physicochemical properties, antioxidant potential, FTIR spectrum and studied the controlled release of phycocyanin. Our results revealed that the optimized formula showed high stability and richness in active compounds.
  PubDate: Fri, 03 Mar 2023 08:41:10 +000
Daniil B. Gogol; Ivan E. Rozhkovoy et al. - Kinetic aspects of malachite
deposition on marble from copper lactate solutions
- Abstract: Experiments were conducted to study the formation of copper minerals on carbonate material (marble) from lactate solutions. Main kinetic parameters were estimated from the curves of copper ions deposition. The reaction rate constant is 4.19×10 -6 s -1 and the effective diffusion coefficient is 1.39×10 -12 m 2 /s at room temperature (25 °C). IR spectra of sediments show good agreement with natural samples of malachite and azurite (Spassk deposit, Central Kazakhstan). The results show the possibility of using organic complexing agents for intensifying the processes of secondary mineral formation of copper carbonate minerals (malachite and azurite) to prevent the dissipation of heavy metal ions in soluble forms from poor deposits and dumps during their remediation.
  PubDate: Fri, 17 Feb 2023 13:28:01 +000
Ali Alaaeddine; Vincent Ladmiral et al. - Synthesis and characterization
of original fluorinated bis-cyclic carbonates and xanthates from a
fluorinated epoxide
- Abstract: The development of efficient methods for the cycloaddition of CX2 (carbon dioxide (X=O) or carbon disulfide (X=S)) with fluorinated epoxides to produce five-membered cyclic carbonates (CCs) or cyclic xanthates (XAs) is a very attractive topic. In this work, the cycloaddition of CX2 with hexafluoropropene oxide (HFPO) was performed in the presence of a lithium bromide (LiBr) catalyst and optimized in terms of temperature, solvent, pressure, and reaction time. Then, the optimized conditions were tried in the cycloaddition of CX2 with 2-(trifluoromethyl)oxirane (TFEO) for reproducibility, leading to the corresponding products in high yields. Finally, two original fluorinated five-membered bis-CCs and bis-XAs were synthesized in high yields (85 and 87%) by reacting CX2 with 1,4-bis(2 ′ ,3 ′ -epoxypropyl) perfluorobutane (BEPFB). All of the resulting compounds were characterized by FTIR, 1H, 19F, and 13C NMR spectroscopy.
  PubDate: Mon, 13 Feb 2023 15:11:26 +000
Comptes+Rendus+Chimie&rft.title=Comptes+Rendus+:+Chimie&rft.issn=1631-0748&rft.date=2023&rft.volume=">Pierre Braunstein - Editorial January 2023 for class="italique">Comptes Rendus Chimie
- Abstract: Pierre Braunstein - Editorial January 2023 for Comptes Rendus Chimie
  PubDate: Mon, 13 Feb 2023 15:11:26 +000
Haining Li; Tiantian Zhang et al. - Preparation of hyperbranched
4-dimethylaminopyridine catalyst for the efficient synthesis of vitamin E
succinate
- Abstract: Sorbitol was employed as the grafting agent to modify nano-silica by the hyperbranched reaction. The obtained carrier was further used to prepare immobilized 4-dimethylaminopyridine (DMAP), which was successfully applied to produce vitamin E succinate. Two crucial steps were systematically investigated during the preparation of hyperbranched loaded DMAP: the epoxy-alcohol addition and N-alkylation reactions. For the epoxy-alcohol addition reaction, the maximum hydroxyl content reached 8.89 mmol/g when the molar ratio of sorbitol to epoxide was 2.5:1, the reaction temperature was 55 °C, the stirring rate was 500 rpm, and the reaction time was 8 h. In the N-alkylation reaction, when the reaction time was 20 h, the reaction temperature was 130 °C, the molar ratio of MAP to K 2 CO 3 was 1:1.5, the KI to MAP molar ratio was 1:1 and the stirring rate was 600 rpm, the highest loading of DMAP reached 5.17 mmol/g. The catalytic performance of the loaded DMAP with different branching levels was evaluated by the acetylation reaction. The highest catalytic activity was observed in the hyperbranched catalyst, which reached 24.97 mmol/h·g. Moreover, the stability of the prepared immobilized DMAP was significantly enhanced. After being used for ten batches, 94.9% of the catalytic activity retention rate was obtained.
  PubDate: Mon, 16 Jan 2023 11:48:32 +000
Iliana Papamichael; Foteini Tsiolaki et al. - Evaluation of the
effectiveness and performance of environmental impact assessment studies
in Greece
- Abstract: As environmental management is becoming increasingly complex, adequate assessment techniques must be utilized to forecast environmental impact trends. The current study aims to investigate the effectiveness of the evaluation system in Greece regarding environmental impact assessment (EIA) concerning projects. Data were extracted from literature and a questionnaire, which was distributed electronically on a Pan-Hellenic scale. Results indicated that the EIA system in Greece has solid foundations with a weak point regarding implementation. Strengths, weaknesses, and threats of EIA institution were analyzed through SWOT-AHP (Strength, Weaknesses, Opportunities, Threats and Analytical Hierarchy Process) analysis. A dominant criterion in the analysis due to the dynamic of the deep economic recession was found to be the economic crisis.
  PubDate: Thu, 12 Jan 2023 08:01:04 +000
Ariane de Espindola; Simona M. Miron et al. - Ultrafiltration operational
conditions influence in the antibacterial activity of native and thermally
treated lysozyme
- Abstract: To obtain high quality final products, biomolecules can be exposed in production lines to stress factors such as heating, stirring and multiple surfaces contact before their commercialization. These factors can induce stability and efficacy loss. In this work, the antibacterial activity of lysozyme (LSZ), a protein used as antibiotic which acts by disrupting the bacterial cell wall, was studied after two operations: heating and ultrafiltration. Antibacterial activity after extreme stress factors is expected to decrease due to conformational changes in the protein molecule. It was observed that ultrafiltration can promote an activity decrease proportional to the applied transmembrane pressure of a non-treated lysozyme. However, when a thermally treated lysozyme (90 °C) was filtered, no additional effect was observed due to the pore passage, independently of the applied pressure.
  PubDate: Fri, 06 Jan 2023 09:56:12 +000
Asmae El Maangar; Sylvain Prévost et al. - Molecular mechanisms induced
by phase modifiers used in hydrometallurgy: consequences on transfer
efficiency and process safety
- Abstract: L’indépendance stratégique passe par la recherche urgente de procédés tenant compte des enjeux environnementaux et économiques lors du recyclage des métaux critiques. L’extraction liquide-liquide est une méthode prometteuse pour récupérer les terres rares dans les déchets d’équipements électriques et électroniques (DEEE). Cependant, un procédé optimisé à l’échelle industrielle n’a pas encore été mis en place. L’une des principales raisons est le manque de connaissances fondamentales, car il faut déchiffrer les équilibres de forces moléculaires à l’origine du transfert d’ions au-delà de la complexation supramoléculaire classique et aussi développer des modèles prédictifs compatibles avec les besoins de conception et de contrôle des procédés de recyclage. Dans tous les procédés d’extraction liquide-liquide, la forte charge du solvant organique en sels/acides métalliques ou en extractant peut parfois conduire à la formation d’une émulsion souvent visqueuse, appelée « troisième phase ». Des modificateurs de phase sont souvent ajoutés à la phase organique afin d’empêcher la formation de cette dernière. Nous montrons ici que le rôle des modificateurs peut être compris selon trois mécanismes moléculaires : comme co-solvant, comme co-surfactant et par solvatation préférentielle. L’effet moléculaire dominant peut être identifié et quantifié en couplant les expériences de tension de surface et de diffusion de neutrons. Dans le cas des modificateurs de phase qui sont des hydrotropes, l’effet co-solvant ou co-surfactant est dominant. Dans le cas des « lipotropes », le mécanisme dominant est la solvatation préférentielle. La connaissance de ces trois mécanismes permettent d’augmenter la sécurité des procédés, puisque l’apparition de l’instabilité de troisième phase peut être mieux évitée. De plus, la compréhension de ces trois mécanismes permet de les prendre en compte dans la prédiction de procédés plus respectueux de l’environnement, en se basant sur la décomposition de l’énergie libre « iénaïque » qui va au-delà des seuls équilibres multiples ou de l’isotherme d’adsorption.
  PubDate: Fri, 16 Dec 2022 09:16:13 +000
Yves Carton - Louis Pasteur face à la maladie du ver à soie
(1865–1870) : du chimiste au biologiste
- Abstract: Louis Pasteur va être amené en 1865, à la demande du gouvernement, à rechercher les causes d’une maladie, la pébrine, qui frappe les élevages du ver à soie, en particulier dans le midi de la France, et y apporter un remède. Il y consacrera 5 années de sa vie (1865–1870), années où il va découvrir la biologie, ce qui représente pour lui une réelle rupture épistémologique et un profond changement de paradigme : de chimiste qu’il est, il découvre et se convertit à la biologie. Comment cela s’est-il réalisé, et dans quelles conditions 'Ces 5 ans de travaux sur les maladies du ver à soie apparaissent comme une réponse à un défi que s’est lancé Pasteur, dans un domaine totalement nouveau pour lui. Il a pu apporter une solution originale pour se débarrasser de ces germes qui infestaient durablement les souches françaises du ver à soie, souches longuement sélectionnées pour leur production en soie. Mais ces résultats vont bien au-delà. Il a pu définir une approche rigoureuse de ce que l’on ne connaissait qu’approximativement : l’infection, la contagion et l’hérédité des maladies. Il a pu en dégager des concepts qui auront plus tard une application bien plus large, à toute pathologie animale ou humaine. Il faut souligner cette capacité de Pasteur à changer radicalement de paradigmes, troquant ceux de la chimie pour ceux de la biologie. A ce moment de son parcours, Louis Pasteur est devenu un biologiste !
  PubDate: Wed, 14 Dec 2022 09:03:08 +000
Asma Nouira; Imene Bekri-Abbes et al. - Valorisation of plastic waste from
the beverage industry through its transformation into adsorbent and solid
fuel materials
- Abstract: Dans la présente étude, des produits de carbonisation et du charbon actif (CA) ont été préparés à partir de bouteilles d’eau, récupérées du point de collecte des déchets à Mourouj, Ben Arous, Tunisie, en utilisant un four tubulaire horizontal rotatif, à l’échelle laboratoire/pilote et par activation chimique et physique. Différents échantillons ont été caractérisés par des isothermes d’adsorption de N 2 , SEM-EDX, XRD, EA ainsi que par la détermination du pH zpc . L’efficacité des CA pour éliminer les herbicides (acide 2-méthyl-4-chlorophénoxyacétique (MCPA) et acide 2,4-dichlorophénoxyacétique (2,4-D)) des solutions aqueuses a également été étudiée. Les résultats obtenus ont démontré qu’une capacité d’adsorption maximale de 192mg·g -1 , pour le MCPA, et de 290mg·g -1 pour le 2,4-D avait été atteinte. Des modèles de pseudo-premier ordre, de second ordre et d’Elovich ont été appliqués à la cinétique d’adsorption, tandis que les modèles des isothermes de Langmuir et de Freundlich ont été appliquées aux isothermes d’adsorption. La possibilité d’utiliser les échantillons étudiés comme matériaux combustibles solides a été évaluée en utilisant l’analyse élémentaire et le pouvoir calorifique supérieur (PCS) numérique. Les résultats expérimentaux ont été comparés aux combustibles solides conventionnels classés dans le graphique de Van Krevelen. Les essais réalisés ont montré que le PCS était de l’ordre de 10,2–11,9 MJ/kg.
  PubDate: Fri, 02 Dec 2022 08:29:32 +000
Guy Dirheimer - Louis Pasteur, chargé du cours de chimie à l’École
supérieure de Pharmacie de Strasbourg (1849–1850)
- Abstract: Les registres comportant les copies du courrier de l’École supérieure de pharmacie de Strasbourg, rendus récemment à la Faculté de pharmacie de Strasbourg, ont été transcrits par Guy Dirheimer. Ces lettres n’avaient jamais été publiées in extenso. Dans cet article nous publions et commentons celles de l’École et du rectorat de Strasbourg qui concernent Louis Pasteur qui y enseigna la chimie du 1 er juin 1849 à fin 1850.
  PubDate: Wed, 26 Oct 2022 12:08:35 +000
Henri Monteil - Louis Pasteur bactériologiste : de l’atténuation de
la virulence à la vaccination
- Abstract: Parmi les nombreuses contributions de Louis Pasteur aux sciences, l’étude des maladies infectieuses touchant les animaux et l’Homme a constitué un point de départ de nos connaissances sur leurs origines, leur prophylaxie et leur prévention. Les streptocoques, le choléra des poules, le charbon et le rouget du porc furent les premières démarches bactériologiques qui ont conduit à énoncer les principes de la protection contre ces maladies. Le concept de vaccination devait en découler et s’avérer fructueux, perdurant jusqu’à nos jours.
  PubDate: Wed, 12 Oct 2022 14:17:38 +000
Khee Chung Hui; Nagaammai Dhanapalan et al. - The synthesis of
amino-functionalized carbon quantum dots-decorated hydroxyapatite as drug
delivery agent
- Abstract: Hydroxyapatite (HAp) was combined with amino-functionalized carbon quantum dots (CQDs) to enhance the optical and surface area properties of HAp. The loading of amino-functionalized CQDs could enhance the luminescence of HAp and its UV–Vis absorbance. Additionally, surface area of HAp could be increased from 84.16 to 129.94 m 2 /g by loading amino-functionalized CQDs. The drug release experiment was conducted using acetaminophen. The release happened slowly for amino-functionalized CQDs/HAp, with full release of acetaminophen being observed after 24 h. The enhanced luminescence composite shows high potential for the composite to be used for the controlled release of drugs.
  PubDate: Wed, 12 Oct 2022 14:16:53 +000
Amélie Bordage; Adama N’Diaye et al. - Prussian Blue analogs and
transition metal K-edge XMCD: a longstanding friendship
- Abstract: Prussian Blue analogs (PBAs) are well-known coordination polymers offering a wide range of properties, and their fundamental understanding requires their investigations by various techniques. One of them is transition metal (TM) K-edge X-ray Magnetic Circular Dichroism (XMCD), which is element selective, bulk sensitive and compatible with a wide range of experimental conditions. This short review presents the reciprocal investigation of PBA with TM K-edge XMCD, from the first studies demonstrating that qualitative local magnetic information could be obtained on PBA from TM K-edge XMCD until our on-going project aiming at fundamentally understanding TM K-edge XMCD thanks to PBAs as model-compounds.
  PubDate: Tue, 20 Sep 2022 09:55:32 +000
Marina Modrić; Marin Božičević et al. - The structure–activity
relationship and computational studies of 1,3-thiazole derivatives as
cholinesterase inhibitors with anti-inflammatory activity
- Abstract: In our previous research, some screened 1,3-thiazole fragments were found to be potent by inhibiting LPS-induced TNFα and IL-8 release with IC50 values in the μM range without cytotoxic activity. In the current study, 1,3-thiazole fragments were further investigated as potent cholinesterase inhibitors prompted by the previously documented anti-inflammatory effect of AChE inhibitors. Molecular docking enabled insight into stabilizing interactions between the selected thiazoles and the active site of AChE and BChE. According to these experimental results, the cholinesterase inhibitory and anti-inflammatory activity of 1,3-thiazoles were correlated and confirmed that the same compounds inhibited LPS-stimulated TNFα cytokine production in PBMCs and enzymes cholinesterases.
  PubDate: Thu, 08 Sep 2022 14:37:55 +000
Zn+ 2 + + +and+metoprolol+adsorption&rft.title=Comptes+Rendus+:+Chimie&rft.issn=1631-0748&rft.date=2022&rft.volume=">Farida Bouyahmed; Fabrice Muller et al. - Chitosan-multilayered graphene
oxide hybrid beads for Zn 2 + and metoprolol adsorption
- Abstract: Chitosan (CS) hydrogel beads and hybrid beads made of a blending of CS hydrogels and Multilayer Graphene Oxide (MGO) were synthesized. The hybrid beads were prepared by gelation in NaOH solution of a 1 wt% CS acid solution with addition of MGO at either 1.5 wt% or 3 wt% loading rates. Prepared beads were characterized by infrared spectroscopy, thermogravimetric analysis (TGA), scanning electron cryo-microscopy and Brunauer–Emmett–Teller (BET) specific surface area measurements. Zn 2+ and Metoprolol (MTP) adsorption kinetics and isotherms were studied on the pristine and hybrid CS hydrogel beads. The adsorption kinetics of Zn 2+ and MTP in hybrid beads is limited by the diffusion to the MGO sites depending on their accessibility. While pure CS is not efficient for the MTP adsorption, the Langmuir-type isotherms of the 3 wt% MGO hydrogel beads (dose: 5 mg/100 mL) show 163 mg·g -1 maximum adsorption uptake. The MTP adsorption kinetics and isotherm suggest a MTP trapping on the MGO anionic sites (carboxylate groups) by electrostatic interactions. The Zn 2+ adsorption capacities are the highest for the 3 wt% MGO hydrogel beads (236 mg·g -1 ), and only of 40 mg·g -1 for the pure CS beads. The presence of Zn 2+ adsorption sites in the hybrid bead, such as MGO carboxylate groups giving electrostatic interactions, and CS amine groups leading to complexation, provides synergic adsorption effects. The competitive adsorption of Zn 2+ with respect to MTP in equimolar mixture was observed on hybrid beads (dose: 200 mg/100 mL) at 2 mmol·L -1 initial total concentration. At pollutant initial total concentration lower than 1.5 mmol·L -1 , no competition occurs. The regeneration at pH 4 of the hybrid beads toward MTP or Zn 2+ adsorption was found to be 35–40% of the initial adsorption uptake for five adsorption/regeneration cycles.
  PubDate: Tue, 06 Sep 2022 14:42:25 +000
Fatma-Zohra Maiouf; Abdenour Boumechhour et al. - Preparation,
characterization of mixed-valence antimony-tin phosphomolybdic
polyoxometalates and application in the cyclohexanone oxidation in the
presence of hydrogen peroxide
- Abstract: In this work, a series of polyoxometalates (POMs), as soluble salts of formula Sn1.5PMo12O40, SbPMo12O40 and H 3-x Sn x1 Sb x2 PMo 12 O 40 (x=2x 1 +3x 2 and x 1 , x 2 = 0–0.75) were synthesized using the cationic exchange method under stoichiometric conditions. They were characterized and tested in the oxidation of cyclohexanone using hydrogen peroxide in the absence of organic solvent, co-catalyst phase transfer compounds or surfactants. UV–Visible and X-ray photoelectron spectroscopic analyses showed a partially reduced state of POM with coexistence of the couples Mo(VI)/Mo(V), Sb(V)/Sb(III) and Sn(IV)/Sn(II), without affecting their structure, results confirmed by FT-IR and Raman spectroscopies. The reversible cyclic voltammetry analysis evidenced the valence change of the Mo species, Mo(VI)/Mo(V). The POMs are found to be active in the cyclohexanone oxidation reaction and among them the most efficient is H 0.75 Sb 0.75 PMo 12 O 40 with 49% of adipic acid yield.
  PubDate: Tue, 06 Sep 2022 14:41:48 +000