Papers by Jean-marc Lévêque
In the search for new forms of synergism, chemists have always looked for novel combinations of t... more In the search for new forms of synergism, chemists have always looked for novel combinations of tools and processes that may produce improvements in efficiency and selectivity, principally, but also time frame, safety, costs and sustainability. Ultrasound has been combined with microwave heating either in loop or in flow mode or simultaneously in batch. Relevant examples are reported on the use of hybrid reactors under combined ultrasound and microwave irradiation.
SpringerBriefs in Molecular Science, 2018
The sound is a mechanical vibration which propagates by elasticity through matter whatever its ph... more The sound is a mechanical vibration which propagates by elasticity through matter whatever its physical state. On liquid state, an interesting and unique physical phenomenon was identified at the end of nineteenth century and designated as cavitation, which is the birth, growth and collapse of tiny gas bubbles. The intensity of bubbles occurrence and of collapse violence is very dependent on the sound frequency. The most energetic cavitation activity occurs when using ultrasound frequencies, i.e. above the upper limit of human hearing (18 kHz). The incident irradiative frequency is therefore of crucial importance leading to effects on chemical systems of physical and/or chemical nature. Several other operational parameters do also greatly influence the cavitation process and are here described as well as most frequent types of ultrasonic devices working either on direct or indirect mode. ‘Hotspot’ theory and generally admitted reacting zones establishing rules of sonochemistry are also examined. Finally, some guidelines for good experimental use of ultrasonic devices are tentatively established by authors based on their own experience.
Fluid Phase Equilibria, 2020
Abstract The physicochemical properties including density, viscosity and refractive index of five... more Abstract The physicochemical properties including density, viscosity and refractive index of five ionic liquids (ILs) consisting of 2-acrylamido-2-methylpropanesulfonate [AMPS] as anion source with ammonium-based cations (tetrabutylammonium [TBA], tetrapropylammonium [TPA] and tetraethylammonium [TEA], tetramethylammonium [TMA] and (vinylbenzyl)trimethylammonium [vbn]) were measured and influence of these properties upon CO2 sorption was investigated. The viscosity and density measurements were taken at atmospheric pressure within the temperature range of (293.15–363.15) K, whereas refractive indexes were determined within (288.15–333.15) K. An increase in the side-carbon chain length of ammonium-based cations resulted in decreased density with a corresponding increase in viscosity and refractive index. Among the studied ILs, [TBA][AMPS] gave the highest viscosity and least density over the whole range of temperature and a higher CO2 sorption of 0.51 mol fraction at 298.15 K and 1 MPa was observed showing dependency of CO2 solubility on the thermophysical properties of studied ILs. Moreover, among investigated ILs, molar volume of [TBA][AMPS] was found to be largest (433.3729 cm3mol-1), which resulted in the higher amount of CO2 sorption in comparison to other investigated ILs. Also, Henry's constant of 1.51 MPa was found for [TBA][AMPS] which was 10.9, 33.4, 44.3 and 24.8% less than [TPA][AMPS], [TEA][AMPS], [TMA][AMPS] and [vbn][AMPS], respectively. The current work offers an in depth study to understand structure-activity relation between physicochemical properties and CO2 solubility of investigated ILs and explores the ways for enhanced CO2 sorption.
Journal of Molecular Liquids, 2018
Background: Renal replacement therapy (RRT) is one of the most expensive in renal medicine. Cross... more Background: Renal replacement therapy (RRT) is one of the most expensive in renal medicine. Cross-sectional studies suggest that life expectancy increases in the general population are associated with a higher burden of RRT. This study tests this hypothesis in a prospective setting among people aged 75+ living in Western Europe. Methods: We gathered sex-specific data for 11 Western European countries in 2005-2014. RRT prevalence on country level was extracted from the ERA-EDTA registry, while data on population size and life expectancy for the 75+ age group came from the Eurostat database. GDP per capita was extracted from the OECD database. To measure the association between RRT prevalence and life expectancy, we performed Poisson regression models separately for each country and for all countries combined. To adjust for confounding, GDP per capita as well as time and country-fixed effects were included. results: Our analysis revealed that living longer coincides with rising RRT prevalence at ages 75+ in Western Europe between 2005 and 2014. On average, a 1-year increase in life expectancy was associated with a roughly 20% increase in RRT prevalence [(95% CI) 21-23% in men and 19-22% in women]. However, after adjustments for confounding were made, the association became insignificant among women and became weaker among men, falling to a level of 11% [(95% CI) 6-17%]. conclusion: Living longer was not necessarily associated with a higher burden of RRT in Western European countries.
Ultrasonics Sonochemistry, 2019
Procedia Engineering, 2016
Owing to their remarkable physical-chemical properties, Ionic Liquids are considered as very prom... more Owing to their remarkable physical-chemical properties, Ionic Liquids are considered as very promising capturing/transportation fluids in biotechnological applications for gaseous pollutants such as Carbon dioxide (CO 2) which can be then remediated by living microorganisms. However, Ionic Liquids are also toxic towards the majority of living species used for remediation purposes among green microalgae. In this study different ionic liquids were tested for their toxicity for different concentrations on one type of commonly used green microalgae, Botryococcus braunii. Ionic liquids bearing long alkyl chain do display higher CO 2 uptake than ioni liquids analogue bearing shorter alkyl chain. This might explain why the production of biomass is dramatically enhanced with 1-octyl-1-Methyl Piperidinium bis (trifluoromethylsulfonyl) imide OMPip[NTf2] compared to 1-Butyl-1-Methyl Piperidinium bis(trifluoromethylsulfonyl) imide BMPip[NTf2] as the latter can supply more CO 2 to the microalgae than the former leading to enhanced organism growth.
Chemical Engineering Journal, 2018
In order to override the slow adsorption kinetics of micropollutants on an activated carbon fabri... more In order to override the slow adsorption kinetics of micropollutants on an activated carbon fabric (ACF) in water medium, different mixing modes, i.e. orbital stirring (250 rpm), low frequency ultrasonic irradiation with either a 20 kHz probe (volumic power: 80 W/L) or a 38 kHz bath (10W/L), were compared to promote the adsorption of ibuprofen (4 ppm initial concentration). The used ACF is formed of wowen braids made of three yarns (~ 300 µm diameter), each of them being composed of microporous fiber bundles (12.6 µm diameter) and its texture was acurately characterized. The adsorption kinetics were studied in buffered phosphate solution (pH 7.5) on a disk, braids or fiber from the fabric and were simulated by a volume diffusion model. The fitted values of the external mass transfer and the volume diffusion coefficients have demonstrated the limitation of the adsorption kinetics under stirring on the fabric disks and braids by the diffusion step within the yarn in the inter-fiber macroporosity. The 20 kHz sonication coupled to the adsorption on ACF led to the degradation of ibuprofen by OH° radicals issued from water sonolysis but whithout damaging further the fabric. The low power irradiation at 38 kHz allowed a sharp acceleration of the adsorption kinetics with respect to the one obtained through orbital stirring. This is explained by a fast mobility of the ibuprofen owing to the presence of standing waves and absence of harsh cavitation as compared to 20 kHz probe system, and confirmed by a fitted diffusion coefficient higher than the one of molecular ibuprofen and of two order of magnitude than in stirring conditions.
Chemosphere, Jan 7, 2017
Over the past decades, Ionic liquids (ILs) have gained considerable attention from the scientific... more Over the past decades, Ionic liquids (ILs) have gained considerable attention from the scientific community in reason of their versatility and performance in many fields. However, they nowadays remain mainly for laboratory scale use. The main barrier hampering their use in a larger scale is their questionable ecological toxicity. This study investigated the effect of hydrophobic and hydrophilic cyclic cation-based ILs against four pathogenic bacteria that infect humans. For that, cations, either of aromatic character (imidazolium or pyridinium) or of non-aromatic nature, (pyrrolidinium or piperidinium), were selected with different alkyl chain lengths and combined with both hydrophilic and hydrophobic anionic moieties. The results clearly demonstrated that introducing of hydrophobic anion namely bis((trifluoromethyl)sulfonyl)amide, [NTF2] and the elongation of the cations substitutions dramatically affect ILs toxicity behaviour. The established toxicity data [50% effective concentra...
AIP Conference Proceedings, 2016
Ionic Liquid (IL), combination of an organic cation with an organic or inorganic cation, possess ... more Ionic Liquid (IL), combination of an organic cation with an organic or inorganic cation, possess some remarkable physical chemical properties such as no virtual vapor pressure (allowing recyclability and reusability), wide liquid range, high thermal and chemical stability, ease to choose hydrophobic/hydrophilic character and wide electrochemical window. Owing to that, they have become increasingly popular as green solvents/additives/catalysts for organic synthetic chemistry, extraction, electrochemistry, catalysis, biomass conversion, biotechnologies and pharmaceutical applications. This is acknowledged by the exponential number of yearly published articles related to them. However, even if these are very widely studied in the international scientific community, they are not or very little used on an industrial scale, particularly because of the lack of data on their toxicity and biodegradability. Notably hydrophobic ILs seems to display higher toxicity towards microorganisms and lower biodegradability co...
Journal of Microbial & Biochemical Technology, 2016
Butylpyridinium thiocyanate [BuPyr]SCN ionic liquid was synthesized by metathesis and characteriz... more Butylpyridinium thiocyanate [BuPyr]SCN ionic liquid was synthesized by metathesis and characterized. NMR spectrum has shown the [BuPyr] cation while FTIR has shown the SCN anion peak which confirms the structure of the synthesized ionic liquid. The ionic liquid was impregnated on activated carbon in order to enhance performance of sulfur dioxide adsorption compared to the non-impregnated raw activated carbon. Two types of activated carbons were used; activated carbon cylindrical granules and cloth. Different percentages of ionic liquid loading (1%, 10% and 20%) were applied. The capacity of the adsorbent for treatment of 10 ppm and 50 ppm SO2 was determined by breakthrough curve analysis whereby optimum breakthrough time was obtained. [BuPyr]SCN impregnated on activated carbon cloth have shown higher adsorption performance.
Procedia Engineering, 2016
Ionic liquids (ILs) are molten salts that possess low melting points and wide solvation propertie... more Ionic liquids (ILs) are molten salts that possess low melting points and wide solvation properties. ILs attracted the attention of the academic and industrial professionals due remarkable properties such as low vapor pressure and thermal stability which make them more environmentally friendly as they can replace volatile organic solvents (VOCs) in many organic reactions. This has brought attention to broaden this research area to overcome the harmful emissions from VOCs in industry. Pyridinium ILs have a wide range of applications in various domains such as material sciences, organic and bioorganic syntheses, biotechnologies, nanotechnology and Enhanced Oil Recovery (EOR). However, available toxicity data in literature is yet scarce and hampers a large scale development. In this study, 18 synthesized ILs were tested against guppy fish and four bacterial strains. Two gram negative bacteria: Salmonella enterica, Vibrio cholera and two gram positive bacteria: Listeria monocytogenes, Staphylococcus aureus were chosen to represent each category of bacteria. Fish test was conducted using OECD guidelines and the "96-well plate" procedure was adopted for the bacterial test using (CLSI M100-S24). Results showed that long alkyl chain length ILs showed higher toxicity than short alkyl chain analogs on all the targeted strains. The highest toxic effect exhibited by pyridinium ILs towards guppy fish was moderately toxic and the rest varied between relatively harmless and practically nontoxic. The highest antibacterial effect indicated slightly toxic effect towards Staphylococcus aureus obtaining EC 50 = 19.3 mg/L. In most cases, pyridinium ILs indicated relatively harmless and practically harmless effects towards bacteria after comparing the EC 50 values obtained with Passino and Smith 1987 hazard ranking.
Journal of Cleaner Production, 2016
ACS Sustainable Chemistry and Engineering, 2013
Biodiesel is produced in multi-stage batch reactors in which mass transfer is a rate limiting ste... more Biodiesel is produced in multi-stage batch reactors in which mass transfer is a rate limiting step. Mass transfer rates may be accelerated with ultrasound (US). In this paper, the performance of continuous flow US reactors, a Rosett US cell reactor, and a batch US reactor are compared to a conventional mechanically stirred batch reactor. The Rosett cell reactor combines acoustic cavitation and turbulence and achieved biodiesel yields greater than 90% in 5 min, whereas the same level of performance in the conventional reactor took more than 90 min. The most significant result of this work lies in achieving biodiesel yields greater than 90% after a single passage of the reagents in a continuous flow reactor in the presence of pulsed ultrasound. This corresponds to a reaction time of 18 s and a rate 300 times faster than the conventional process.
Synlett, 2007
A novel method is described for the one-pot synthesis of various ionic liquids in a competitive t... more A novel method is described for the one-pot synthesis of various ionic liquids in a competitive time. By using ultrasonic irradiation, different families of nitrogen-bearing ionic liquids can be obtained in a solvent-free or in aqueous medium, which gives a greener touch to the overall process.
Like other enabling technologies, ultrasonication has moved progressively from batch to flow cond... more Like other enabling technologies, ultrasonication has moved progressively from batch to flow conditions, which are more suitable for large-scale applications and industrial purposes. Without discussing comprehensively, the subject of sonochemistry underflow, this chapter provides some background and practical considerations with a focus on chemical synthesis in following the heading of this monograph. A deeper analysis is presented for miniaturized systems as microfluidics and machine-assisted approaches will doubtless be the future of chemistry. Ultrasound in microchannels helps to prevent clogging while enhancing considerably mass transfer. Moreover, such applications will require the design of more efficient micro-sonoreactors and an accurate control of external parameters.
Acoustic cavitation invariably combines chemical and mechanical effects that stem from bubble col... more Acoustic cavitation invariably combines chemical and mechanical effects that stem from bubble collapse in liquids. Strategies to harness preferentially the role of mechanochemistry in sonochemistry have been invented and developed in recent years, demonstrating enormous versatility from synthesis and catalysis to biology and analytical monitoring. Most cases involve polymers containing weak bonds that can be fragmented by sonication. The effects are dependent largely on both the nature of substrates and the strength of cavitational collapse.
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Papers by Jean-marc Lévêque