Terephthalic acid synthesis at higher concentrations in high-temperature liquid water. 2. Eliminating undesired byproducts

We synthesized terephthalic acid (TPA) from p -xylene at an initial concentration above its solubility limit in high-temperature liquid water (HTW). The nominal p -xylene loading at the reaction conditions was 0.4 mol L −1 , which is the highest reported to date for generation of high TPA yields (>70 mol %) in HTW. The presence of two liquid phases during the reaction did not appear to accelerate the rate, unlike behavior reported for some other organic reactions done “on water” at lower temperatures. Adding oxygen gas in a large increment during synthesis produced a black liquid and a black solid byproduct, which is a previously undocumented problem. Adding oxygen in smaller increments prevented formation of the liquid and solid byproducts and also provided high selectivities (90 mol %) and yields (>70 mol %) of TPA. These results demonstrate the feasibility of HTW as a medium for TPA synthesis at p -xylene concentrations even higher than its solubility limit. © 2009 American Institute of Chemical Engineers AIChE J, 2009Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63001/1/11761_ftp.pd

Nouveaux développements sur l'utilisation en synthèse organique des liquides ioniques et de la technologie micro-ondes pour la catalyse et la chimie combinatoire

Les travaux présentés dans ce mémoire concernent de nouveaux développements sur l’utilisation en synthèse organique des liquides ioniques et de la technologie micro-ondes pour la catalyse et la chimie combinatoire. La première partie est consacrée aux rappels bibliographiques relatifs aux liquides ioniques en replaçant ces composés dans un contexte général (description des propriétés, préparation et applications en synthèse organique, en catalyse). Une description générale est ensuite effectuée sur les micro-ondes avec quelques applications récentes en synthèse et notamment, des applications relatives aux liquides ioniques. L’utilisation de liquides ioniques comme catalyseurs dans le cadre de réactions d’estérification et de cycloaddition dipolaire-1,3 est décrite. Dans un premier temps, l’effet catalytique de liquides ioniques recyclables à caractère acide de Brönsted est abordé sur une série de réactions d’estérification. L’étude suivante concerne les réactions de cycloadditions dipolaires-1,3 en milieux inusuels (sans solvant, activation micro-ondes focalisées et liquides ioniques) faisant intervenir la réactivité d’imidates dérivés d’aminoesters. Le travail fait l’objet d’une étude sur la stéréosélectivité et la cinétique des réactions de cycloaddition dipolaire-1,3 suivant deux processus : intermoléculaire et intramoléculaire. La dernière partie aborde la mise au point et l’analyse physico-chimique de nouvelles phases liquides ioniques appliquées à la chimie combinatoire. L’emploi de ces supports est décrit dans le cadre de réactions variées (condensation, cycloaddition dipolaire-1,3, synthèse de 4-thiazolidinones) en utilisant notamment la technologie d’Irradiation Micro-Ondes Focalisées Sans Solvant (IMOF-SaSo).RENNES1-BU Sciences Philo (352382102) / SudocSudocFranceF

Rapid and clean synthesis of phthalimide derivatives in high-temperature, high-pressure H2O/EtOH mixtures

A variety of phthalimide derivatives have been synthesised effectively in high-temperature, high-pressure H2O/EtOH mixtures (HTHP-H 2O/EtOH) as the solvent. This clean method is based on the condensation of o-phthalic acid and amines and affords phthalimide compounds as pure crystals in most cases, because of the dehydrating effect and change in solvation properties of H2O/EtOH at high pressures and temperatures. After conducting a series of model reactions, it was found that a mixture, 1/1 v/v H2O/EtOH, was appropriate for obtaining good yields combined with high purity of the phthalimides. Moderate to excellent yields were obtained depending on the nature of the amine. Aromatic amines generally afforded higher yields than aliphatic ones except for 3-hydroxypropylamine, where a yield up to 95% was obtained. © The Royal Society of Chemistry

Ecofriendly Fast Synthesis of Hydrophilic Poly(ethyleneglycol)-Ionic Liquid Matrices for Liquid-Phase Organic Synthesis

New, hydrophilic poly(ethyleneglycol)-ionic liquids have beensynthesized and investigated, based on 1,3-disubstituted imidazolium cations and fluorinated anions (BF4 -, PF6 -,(CF3SO2)2N-, or NTf2 -). A series of typical solvent-free reactions have been safely realized using a focused microwave reactor for the preparation of imidazolium chloride precursors in yields ranging from 73 to 94% followed by quantitative anion metathesis exchanges. The poly(ethyleneglycol)-ionic liquid matrices were also characterized by NMR (1H, 13C), massspectrometry (MS), and their dynamic viscosity was determined at 25 °C. These poly(ethyleneglycol)-ionic liquid phases (PEGILPs) as task-specific ionic liquids are promising tools for synthetic applications in liquid-phase combinatorial chemistry

Ionic Liquid Technology: A New Tool for Combinatorial Chemistry. Applications in Heterocyclic Chemistry mediated by Microwave Dielectric Heating.

International audienc