Showing papers in "Green Chemistry in 2000"

TL;DR: In this paper, four-component condensation of benzil, aromatic aldehydes, primary amines and ammonium acetate catalyzed by zeolite HY and silica gel without any solvent under microwave irradiation leads to tetrasubstituted ======姫imidazoles in high yields and purity.

TL;DR: In the last few years, these reagents have been increasingly substituted by cleaner alternative and inherently safer compounds since the goal of the modern environmentally friendly synthetic chemistry is the development and optimisation of reaction conditions to reduce or eliminate the use and production of hazardous materials while increasing energy usage as mentioned in this paper.

TL;DR: In this paper, the authors explore various applications of green chemistry methodologies to all stages of a product or process life cycle, and explore how improvements can be made to address environmental problems and to decrease impacts on human health and the environment.

TL;DR: In this paper, the authors tried to quantify the sustainability of technological processes based on thermodynamics with energy carriers and materials (products, waste, etc.) expressed in the same measure of energy exergy (Joule).

TL;DR: In this article, a simple, efficient and environment-friendly procedure is developed for the condensation of malonitrile with aromatic, hetero-aromatic and aliphatic aldehydes in water.

TL;DR: The synthesis of the pharmaceutical Pravadoline is achieved in high yield without the production of noxious waste products; the ionic liquid can be recycled and reused in this methodology.

TL;DR: Approximately 2000 compounds of chlorine, both inorganic and organic, are known to be produced, transformed, transported and degraded in a range of natural geological, chemical or biochemical processes in most of the earth's environmental compartments as discussed by the authors.

TL;DR: In this paper, the performance of blue ceramic pigments with the addition of cobalt in the willemite lattice was studied and the results showed that an intense and more blue pigment was obtained based on the willetite lattice, with an optimised, low Co content, ranging from 25 mol% Co (Co 0.5Zn1.5SiO4) to 2.5 mol% CO (Co0.05Zn 1.95SiO 4 ).

TL;DR: In this article, the performance of a thin film reactor in the form of a spinning disc was described for continuous condensation polymerisation of esters, and test results suggest that it may be possible to significantly enhance the rate of polymerisation by addressing the mass transfer and mixing limitations.

TL;DR: Condensation reactions of aldehydes and amines occur efficiently in a water suspension medium, and the reaction products are collected easily by filtration as mentioned in this paper, and they can be obtained easily by filtering.

TL;DR: The utility of ionic liquids as a safe recyclable reaction for the one-pot aza-Diels-Alder reaction to produce 5,6-dihydro-4-pyridone derivatives is discussed in this article.

TL;DR: The use of boron-containing reagents in palladium-assisted bond forming reactions (Suzuki reaction) has gained prominence because of the vast array of functionally and efficiently substituted borons containing reagents available to the organic chemist as mentioned in this paper.

TL;DR: A clean and environmentally benign process to convert benzylic and allylic alcohols into the corresponding carbonyl compounds using a catalytic amount of palladium on activated charcoal under an ethylene atmosphere is developed in this paper.

TL;DR: In this article, a study on the behavior of vinyl pyrazoles, pyrazolyl imines and pyrazolopyridines as dienes or dipoles is reported.

TL;DR: In this paper, the first time that the Wacker reaction can be carried out smoothly in supercritical carbon dioxide or supercritical ROH/supercritical CO2 was reported, and it was shown that both scCO2 and co-solvent can remarkably affect the selectivity towards methyl ketone.

TL;DR: In this paper, the utility of molten salts as a one-pot reaction medium for the synthesis of heterocyclic compounds is discussed. But they do not consider the use of a single-stage process.

TL;DR: In this paper, solvent-free and ionic liquid reaction media were used for cyclic cyclotriveratrylene (CTV) synthesis under mild conditions, which obviates the need for large quantities of organic solvent and strong dehydrating acids yet provides pure crystalline product in high yields.

TL;DR: In this article, the condensation of phenoxyethanol with fluoren-9-one using a Ti4+ cation-exchanged montmorillonite as a strong solid acid catalyst is described.

TL;DR: Novel guanidine bases supported on silicas and Micelle Templated Silicas have been prepared, and investigated in the base catalysed epoxidation of electron deficient alkenes with excellent conversions and selectivities both with respect to the alkene and the primary oxidant.

TL;DR: The reaction is not 100% atom efficient (1 mole of acetone is evolved for each mole of coumarin produced) but it is a significant improvement on previously described methods for the synthesis of such compounds.

TL;DR: The relevance of Lewis-acid catalysed oxybromination systems as bromoperoxidase enzyme mimics and the potential application of enzymatic halogenation as a ‘green’ bromination option are discussed.

TL;DR: In this paper, the anti-selective substitution reactions of 1,3-diphenyl-3-acetoxyprop-1-ene with DMM were studied in 1-butyl 3-methylimidazolinium as an ionic solvent and were catalyzed by Pd0 complexes of two homochiral (S,R)-BPPFA and (R,S)-bPPFDEA with the recycling of the catalytic system being tested.

TL;DR: In this paper, the use of a bimetallic Pt,Bi/graphite catalyst for the efficient aerobic selective oxidation of primary allylic alcohols is reported. But the influence of the allylic bond location, substrate conformation, and reaction parameters in modifying aldehyde yield are discussed.

TL;DR: The Royal Society of Chemistry 2000 as discussed by the authors has published a survey on the state of the art in the field of chemistry, including a survey of the state-of-the-art tools and techniques used by the Royal Society.