Z. Mouloungui

Interest of combining an additive with diesel-ethanol blends for use in diesel engines

Abstract Two organic additives were selected for their different physico-chemical parameters to study the behaviour of a diesel–ethanol mixture. These compounds had a glycerol skeleton bearing heteroatoms and amino-ether, hydroxyl, nitrate and nitramine functional groups. Properties directly related to engine parameters (viscosity, cetane number, heat content, volatility) and those characterising fuel quality (homogeneity, cold properties, anticorrosiveness and volatility) were investigated. Fuel formulations were prepared with 2% additive and ethanol contents between 10 and 20% in volume in relation to the diesel fuel. Blends, with or without additive, are compared in two diesel engines with direct and indirect injection. Engine behaviour seemed to be improved in the presence of additives with a reduction of pollutant emissions in exhaust gas, cyclic irregularities and ignition delay. No trouble shooting, knocking or vapor-lock phenomenon were encountered during this study.

New Synthesis of Substituted Difuryl or Dithienyl Methanes

Abstract New trisubstituted methanes derivatives are quantitatively and selectively obtained by condensation of 2-methylfuran or 2-methylthiophene with diverse aldehydes using macroporous ion-exchange resins as catalyst. Hydration rate of organic phase and sulfonic sites of catalyst determines a proper reaction progress.

Synthesis of α,β Unsaturated Esters Using a Solid-Liquid Phase Transfer in a Slightly Hydrated Aprotic Medium

Abstract The condensation reaction of alkylphosphonates with variously functionnalysed aldehydes in the presence of solid potassium carbonate in low hydrated aprotic media leads to the selective formation of αβ-unsaturated esters E in high yields.

High concentration of 1-(3-)monoglycerides by direct partial esterification of fatty acids with glycerol

An improved method for the production of monoglycerides (MO) by direct esterification of fatty acids with glycerol was developed. The reaction medium was composed of oleic acid (72% purity, OA), glycerol (Gly), dodecylbenzene sulfonic acid (DBSA) as catalyst, and emulsifying agent, as well as of a molecular sieve as drying agent. Partial esterification of glycerol by oleic acid is carried out in either a batch reactor and in a column filled with a molecular sieve according to a continuous process. In a discontinuous batch reactor, the OA/Gly/DBSA system gives 28% of 1-(3-)MO and strong proportions of di- and triesters. The addition of the 3A molecular sieve to this system makes it possible to increase the selectivity in 1-(3-)MO (47%). However, the reaction carried out in a column filled with a 3A molecular sieve produced a mixture containing 60% of 1-(3-)MO after deacidification and removal of the catalyst and shows the advantage of a continuous process. Hohe Konzentration von 1-(3-)Monoglyceriden durch direkte partielle Veresterung von Fettsauren mit Glycerol.Es wird eine verbesserte Methode zur Herstellung von Monoglyceriden (MO) durch direkte Veresterung von Glycerol mit Fettsauren beschrieben. Der Reaktionsnahrboden bestand aus Olsaure (72% Reinheit, OA), Glycerol (Gly), Dodecylbenzol-Sulfonsaure (DBSA) als Katalysator und Emulgiermittel, sowie einem Molekularsieb als trocknendes Mittel. Die teilweise Veresterung von Glycerol durch die Olsaure wurde in einem Batch-Reaktor im diskontinuierlichen System sowie einem Saulenreaktor mit einem Molekularsieb im kontinuierlichen System durchgefuhrt. Im diskontinuierlich geschuttelten Reaktor erreicht das System OA/Gly/DBSA 28% von 1-(3-)MO, aber auch einen grosen Anteil von Di- und Triestern. Der Zusatz des Molekularsiebs 3A zu diesem System ermoglicht ein Verstarken der Selektivitat in 1-(3-)MO (47%). Die besten Ergebnisse werden erzielt, wenn die Reaktion in einer Saule mit Molekularsieb 3A durchgefuhrt wird. Die Mischung enthalt in diesem Fall 60% 1-(3-)MO nach Entsauerung und Ausscheidung des Katalysators, und dieses Verfahren hat zudem den Vorteil, ein kontinuierliches Verfahren zu sein.

Synthesis of optically active amides from β-furyl and β-phenyl esters by way of enzymatic aminolysis

Candida antarctica lipase efficiently catalyses the aminolysis of non-activated esters with a β-furyl or β-phenyl group; use of racemic amines gives the corresponding optically active amides with high enantiomeric excess.

Synthesis and analysis of the C1C18 alkyl oleates

Abstract The C1–C18 alkyl oleates were prepared in n-hexane by esterification of oleic acid with either the primary and secondary C1–C6 alcohols or the primary fatty C8–C18 alcohols. The esterification was acid-catalyzed in the presence of p-toluene sulfonic acid (p-TSA) in a pseudo-homogeneous phase, or in the presence of the sulfonic macroporous resin (K2411) in the heterogeneous phase. The purified alkyl oleates were characterized by 13C-NMR. The oleic acid/alkyl oleate mixtures were analyzed by high-performance liquid chromatography (HPLC).

A Simplified Wittig Synthesis Using a Solid/Liquid Transfer Process. VIII - Specific Behaviour of Methyltriphenylphosphorane During Condensation with Phenolic Aldehydes

Abstract Vinylphenols are obtained in a single-step reaction using phenolic aldehydes according to easy operating conditions involving high temperature in the reaction medium. Phenolic compounds are separated by ion-exchange resins.

Synthesis of α, β-Ethylenic Esters in a Heterogenous Solid-Liquid Medium. II - A Transesterification Reaction Linked to a Wittig-Horner Reaction in a Protic Medium

Abstract The condensation reaction of ethyl or methyl phosphonates with variously functionnalysed aldehydes in the presence of solid potassium carbonate in alcoholic media leads to the direct formation of E α, β unsaturated esters. The alkyl, aryl or heteroaryl substituents of the double bond are provided by the aldehyde and the solvent. The method used involves a solid-liquid transfer process.

Reactions de wittig-horner et de transesterification en une operation par activation anionique de liaisons C-H et O-H en milieu heterogene carbonate de potassium/alcool

Abstract The Wittig-Horner reaction carried out in various alcohols is accompanied by transesterification of the alkyl radical of the α, β-ethylenic ester formed. The occurrence of these two reactions in the same reaction medium is affected by the behavior of: i) the alcohol (solvent and reagent), ii) potassium carbonate (reagent and catalyst). The propensity for the two reactions to occur was found to depend on the polarity of the alcohol. Protic alcohols speeded both the Wittig-Horner and the subsequent transesterification reaction. Both reactions were quantitative despite the use of non-stoichiometric amounts of potassium carbonate. Regeneration in situ of the solid base observed in aprotic medium was markedly enhanced under these reaction conditions. The mechanism proposed for these two reactions incorporates this regeneration process.

Cesium Carbonate in Weakly Hydrated Solid/Liquid Heterogeneous Medium: A New Reagent for Anionic Activation Synthesis

Abstract Transformation of acidic hydrogen carrying aldehydes- in corresponding ethylenic esters or ethers is carried out in the presence of cesium carbonate. Cesium carbonate proves to be an efficient reagent for any transformation by anionic activation of poly-functional molecules.