Showing papers in "Green Chemistry in 2001"

TL;DR: A series of hydrophilic and hydrophobic 1-alkyl-3-methylimidazolium room temperature ionic liquids (RTILs) have been prepared and characterized to determine how water content, density, viscosity, surface tension, melting point, and thermal stability are affected by changes in alkyl chain length and anion.

TL;DR: In this paper, an approach to quantitatively and systematically evaluate synthetic organic reactions and processes is described, which allows chemists to clearly assess whether or not chemistries and chemical processes are "greener".

TL;DR: In this article, the dipolarity of 1-butyl-3methylimidazolium hexafluorophosphate (bmimPF6) was investigated using both absorbance (Reichardt's betaine dye) and fluorescence (pyrene, dansylamide, Nile Red, and 1-pyrene carbaldehyde) probes.

TL;DR: In this paper, the microwave assisted Suzuki cross-coupling of arylboronic acids with aryls halides has been investigated and polyethylene glycol (PEG) is found to be an inexpensive and non-toxic reaction medium for the microwave-assisted Suzuki cross coupling.

TL;DR: In this paper, the influence of fiber surface modifications like dewaxing, methyl methacrylate grafting on the thermal and electrical properties of coir (coconut) and sisal fibers has been investigated.

TL;DR: In this article, a range of supported palladium complex-catalysed Suzuki catalysts are described with notable features including fast and efficient reactions, excellent catalyst recyclability, and total catalyst stability under the reaction conditions.

TL;DR: In this article, the synthesis of dimethyl carbonate from methanol and CO2 was studied in the presence of methyl iodide and various base catalysts, including potassium carbonate.

TL;DR: A set of metrics has been developed which enables a simple assessment to be made of batch processes in terms of waste, energy usage, and chemistry efficiency as discussed by the authors, which is intended to raise awareness of green chemistry by providing a tool to assist chemists in monitoring progress in reducing environmental impact.

TL;DR: In this article, a zeolite catalyzed, single step and environmentally friendly process for the synthesis of dihydropyrimidinones, a pharmacologically important class of compounds, is reported.

TL;DR: Palladium-catalysed carbonylation of aryl halides with======alcohols or NEt2H proceeds in ionic liquid media======(1-butyl-3methylimidazolium tetrafluoroborate or hexafluorophosphate) as mentioned in this paper.

TL;DR: The LDH-F hydrotalcite catalysts were found to be an efficient, environmentally attractive and selective solid base catalysts for 1,4-Michael addition and also for simple synthesis of β-unsaturated esters and nitriles by Knoevenagel condensation.

TL;DR: In this paper, a colorimetric method to monitor the production of ionic liquid precursors is developed, which is based on the determination of 1-methylimidazole with copper(II) chloride.

TL;DR: Potassium carbonate supported solventless synthesis of thiohydantoins under microwave irradiation was described in this paper, which not only eliminates the need for external base to neutralize HCl evolved but enables aqueous work up, thus rendering the reaction procedure free of organic solvents in both the reaction step and work-up, procedure.

TL;DR: An overview of the strategies adopted in flow analysis towards cleaner analytical methods is presented, and Automation, employment of solid-phase reagents and miniaturization are highlighted as alternatives for waste minimization.

TL;DR: In this article, a simple and environmentally friendly procedure has been developed for the reaction of Meldrum's acid with salicylaldehydes, and 3-Carboxycoumarins 5 were synthesised in high yields and excellent selectivities.

TL;DR: In this article, the authors explored the generation of hydrogen peroxide directly from hydrogen and oxygen using liquid CO2 as the solvent and a CO2-soluble palladium catalyst.

TL;DR: In this article, a simple procedure at low cost was proposed to reduce sterically hindered 2,6dimethylnitrobenzene and chemoselective for nitro groups; ester, amide and halide substituents on the rings are unaffected.

TL;DR: In this article, the presence of a small amount of water in the reaction medium was shown to be of crucial importance, and a variety of different aluminas showed a similar catalytic behavior.

TL;DR: In this paper, efficient, large scale-adaptable protocols are described for the straightforward conversion of D-fructose-derived HMF and 5-glucosyloxymethylfurfural (GMF) into hydrophilically substituted N-heterocycles of the pyrrole, pyridazine, thiophene and benzodiazepine types.

TL;DR: The photoreactions between 1,4-quinones (1 and 4) and aldehydes (2 and 5), yielding acylated hydroquinones as sole products, were investigated under artificial and solar irradiation conditions.

TL;DR: TransChalcones have been obtained in good yields and high selectivities following an environmentally friendly methodology by using======montmorillonite KSF as a reusable heterogeneous catalyst as discussed by the authors...

TL;DR: In this article, the hazardous air pollutants (MEK, MIBK and toluene) used in magnetic tape coatings are replaced with ethyl lactate, which is not a hazardous air pollutant and made from renewable resources.

TL;DR: In this paper, the authors evaluated the degree of substitution from a combination of NMR and LSIMS as well as chromatographic and gravimetric measurements for the etherification of sucrose in aqueous solutions.

TL;DR: In this article, the authors used an additional electronic level of energy in the forbidden band of cerianite forbidden band, arising from unpaired 4f electrons of lanthanide ions, for the coloration of porcelainised stoneware bodies.

TL;DR: In this article, resorcinol and benzaldehyde derivatives are prepared in polypropylene glycol, which is readily recycled, and the solvent-free method measures up well with respect to energy usage, solvent wastes and associated hazards, reaction time and yield.

TL;DR: In this article, the Knoevenagel addition of aryl aldehydes with nitroacetonitrile 2 in water followed by dehydration of β-nitroalcohols 3, allows (E)-2-aryl-1-cyano-1 -nitroethenes 4 to be prepared by a one-pot procedure without using organic solvents.

TL;DR: Several primary aromatic amines, substituted with electron-donating groups, were converted to their corresponding nitro compounds in good to excellent yields with sodium perborate tetrahydrate (SPB) in micellar media in the presence of a catalytic amount of H3PW·nH2O as mentioned in this paper.

TL;DR: In this article, simultaneous microwave and ultrasound irradiation using an innovative and efficient reaction apparatus was used to promote the hydrogeninolysis of esters, and the result showed that the esters were more hydrically stable.

TL;DR: In situ infrared spectroscopic studies have revealed that the mechanism of the Friedel-Crafts acetylation of benzene is exactly the same in ionic liquids as in 1,2-dichloroethane as discussed by the authors.

TL;DR: In this article, a Zeolite H-FER catalyzes the acetylation of alcohols, phenols and thiols using acetic anhydride under solventless conditions in excellent yields.