Physical methods for measurement of the HLB of ether and ester non-ionic surface-active agents: H-NMR and dielectric constant

Rabaron, A.; Cave, G.; Puisieux, F.; Seiller, M.

doi:10.1016/0378-5173(93)90319-b

Cited by 16 publications

(6 citation statements)

References 17 publications

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“…The chosen ether solvents differ in polarity (represented by their ɛ), boiling point, and chain length (or molar mass) which is shown in Table 1 [from CRC (2003[from CRC ( -2004, Wohlfarth (2008)]. The dielectric constant is known to be proportional to the solvents polarity (Rabaron et al, 1993). Among these properties, the observed syngas conversion pattern followed the ɛ of the solvents with the optimum around ɛ = 7.2 for diglyme.…”

Section: Resultsmentioning

confidence: 99%

The Role of Solvent Polarity on Low-Temperature Methanol Synthesis Catalyzed by Cu Nanoparticles

2017

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Methanol syntheses at low temperature in a liquid medium present an opportunity for full syngas conversion per pass. The aim of this work was to study the role of solvents polarity on low-temperature methanol synthesis reaction using eight different aprotic polar solvents. A "once through" catalytic system, which is composed of Cu nanoparticles and sodium methoxide, was used for methanol synthesis at 100°C and 20 bar syngas pressure. Solvent polarity rather than the 7-10 nm Cu (and 30 nm Cu on SiO2) catalyst used dictated trend of syngas conversion. Diglyme with a dielectric constant (ɛ) = 7.2 gave the highest syngas conversion among the eight different solvents used. Methanol formation decreased with either increasing or decreasing solvent ɛ value of diglyme (ɛ = 7.2). To probe the observed trend, possible side reactions of methyl formate (MF), the main intermediate in the process, were studied. MF was observed to undergo two main reactions; (i) decarbonylation to form CO and MeOH and (ii) a nucleophilic substitution to form dimethyl ether and sodium formate. Decreasing polarity favored the decarbonylation side reaction while increasing polarity favored the nucleophilic substitution reaction. In conclusion, our results show that moderate polarity solvents, e.g., diglyme, favor MF hydrogenolysis and, hence, methanol formation, by retarding the other two possible side reactions.

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Section: Resultsmentioning

confidence: 99%

The Role of Solvent Polarity on Low-Temperature Methanol Synthesis Catalyzed by Cu Nanoparticles

2017

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“…41 The term I gph denotes the integration amplitude of the hydrophilic groups and I tot refers to the total integration amplitude of the protons in the molecule. The ratio H describes the relative hydrophilic part of the molecule and can be used to estimate HLB value applying the equation described of Rabaron et al 51 ( eqn (3) ). H = I gph / I tot HLB = 60 H /( H + 2) …”

Section: Methodsmentioning

confidence: 99%

Lipase-catalyzed acylation of levoglucosan in continuous flow: antibacterial and biosurfactant studies

et al. 2022

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“…These products are produced by Sidobre Sinnova (Meaux-Beauval, France) and are described in Table I. The HLB values are recorded by a RMN method [15]. The oil phase was a mineral oil.…”

Section: Raw Materialsmentioning

confidence: 99%

Rheology: how to characterize and to predict the evolution of W/O/W multiple emulsions

Terrisse

Seiller

Rabaron

et al. 1993

Intern J of Cosmetic Sci

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Synopsis The purpose of this work was to compare the evolution of three multiple emulsions (ME) by different controls. The series of water-in-oil-in-water (W/O/W) multiple emulsions were elaborated and controlled by both the usual analyses which permitted the classification of the multiple emulsions with respect to their thermal stability, and the rheological oscillatory and flow analyses which are polyvalent methods. Further, these allow the 'identity card' of the multiple emulsion to be drawn, its evolution to be followed, and moreover, its behaviour being foreseen by simulating ageing by shear. Three different behaviours are observed; a destructuration, a phase inversion and stability. Résumé L'objectif de ce travail est de comparer, à l'aide de différentes analyses, l'evolution de trois émulsions multiples H/L/H. Ces émulsions sont contrôlées par des analyses classiques qui permettent de classer les émulsions en fonction de leur stabilité thermique, et des analyses rhéologiques en dynamique et en écoulement qui permettent de dresser la 'carte d'identité' de l'émulsion multiple, de suivre son évolution et enfin de prévoir son comportement après simulation du vieillissement par le cisaillement. Trois comportements sont observés; une destructuration, une inversion de phase et une stabilité.

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Physical methods for measurement of the HLB of ether and ester non-ionic surface-active agents: H-NMR and dielectric constant

Cited by 16 publications

References 17 publications

The Role of Solvent Polarity on Low-Temperature Methanol Synthesis Catalyzed by Cu Nanoparticles

The Role of Solvent Polarity on Low-Temperature Methanol Synthesis Catalyzed by Cu Nanoparticles

Lipase-catalyzed acylation of levoglucosan in continuous flow: antibacterial and biosurfactant studies

Rheology: how to characterize and to predict the evolution of W/O/W multiple emulsions

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