Showing papers in "Green Chemistry in 2012"

TL;DR: In this article, new natural and biorenewable solvents are prepared in this work consisting of high melting temperature starting materials that form low transition temperature mixtures (LTTMs).

TL;DR: In this article, the authors give an overview on the most important advances made by the scientific community in the last 15 years in the field of aerobic oxidations of alcohols catalyzed by transition metals in the form of homogeneous catalysts and, more recently, nanoparticles.

TL;DR: A review of physicochemical data of these reaction media and highlights recent advances in their use in organic synthesis and biotransformations can be found in this article, where the authors highlight the need to replace hazardous and harmful solvents with green or sustainable media.

TL;DR: In this paper, a one-pot, hydrothermal synthesis of nitrogen and sulfur dual-doped carbon aerogels is presented, derived from a previously published hydro-thermal carbonization approach, and the synergistic effect of combined sulfur- and nitrogen-doping in the catalysis of the ORR is expected to be significant to future research concerning the improvement of heterogeneous, metal free, carbon-based catalysts.

TL;DR: In this paper, the development made into the application of continuous flow reactors for sustainable chemical research and production is discussed, with aspects of continuous processing featuring heavily in efforts towards increasing the green prospects of pharmaceutical and fine chemical manufacturing.

TL;DR: In this paper, a review summarizes recent results of multicomponent reactions obtained in unconventional media including water, ionic liquids, polyethylene glycol and bio-based solvents.

TL;DR: In this article, the Kamlet-Taft parameters of glycerol and poly(ethylene glycol have been resolved with new data, including the normalized Reichardt's parameter (ENT), Nile red λmax, and Kamlet's parameters (α, β, and π*) for switchable-polarity solvents.

TL;DR: In this paper, a simple approach for the preparation of carbon nanodots (C-dots) from coffee grounds was developed. But the method was not suitable for the extraction of C-Dots for cell imaging and surface-assisted laser desorption/ionization-mass spectrometry of angiotensin I and insulin.

TL;DR: A series of room temperature ionic liquids, in which cholinium acts as the cation and amino acids as the anions, were prepared via a simple and green chemical route and characterized, and dissolved lignin efficiently and selectively.

TL;DR: A low energy intensive process for the production of diesel fuel has been delineated from both 5-(hydroxymethyl)furfural (HMF) and its sugar precursor D-(−)-fructose, in the presence of solid acid catalysts as mentioned in this paper.

TL;DR: In this article, the authors reported the preparation and characterization of lignin-based, partially carbon-neutral thermoplastics, when coupled with telechelic polybutadiene soft segments at proper feed ratios.

TL;DR: In this article, the importance of Diels-Alder cycloaddition reactions when olefins are co-fed with furanics over ZSM-5 was investigated.

TL;DR: In this paper, the mechanism of selective oxidation of aqueous 5-hydroxymethylfurfural (HMF) at high pH was studied over supported Pt and Au catalysts.

TL;DR: In this article, a simple one-pot green chemical method for the biosynthesis of gold nanoparticles by reducing chloroauric acid (HAuCl4) with protein extract of Rhizopus oryzae to produce novel gold nano-bio-conjugates (AuNBCs) was described.

TL;DR: Gold nanoparticles deposited on nanocrystalline magnesium oxide is a very efficient catalyst for the reduction of nitro-arenes in aqueous medium at room temperature as discussed by the authors, and the reaction kinetics of reduction of 4-nitrophenol to 4-aminophenol has been studied by UV-visible spectrophotometry, and its apparent rate constant has been determined and compared with those of other supported gold catalysts.

TL;DR: In this paper, several copper based catalysts were prepared, characterized and evaluated for the hydrogenation of levulinic acid and its methyl ester in methanol and water respectively.

TL;DR: AlCl3·6H2O in a biphasic medium of water/tetrahydrofuran (THF) is effective for the synthesis of 5-hydroxymethylfurfural (HMF) from glucose-based carbohydrates.

TL;DR: In this article, the cycloaddition reactions of CO2 with various epoxides to form five-membered cyclic carbonates catalyzed by chitosan functionalized 1-ethyl-3-methyl imidazolium halides (CS-EMImX, X = Cl, Br) without additional solvent and metal co-catalyst were achieved in high yield and selectivity.

TL;DR: In this paper, a sustainable process for the hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL) is reported, using a commercial ruthenium supported catalyst in combination with a heterogeneous acid co-catalyst, such as the ion exchange resins Amberlyst A70 or A15.

TL;DR: In this article, the authors studied the selectivity of 5-hydroxymethylfurfural (HMF) to 2,5-di-hydroxy-methyl-tetrahydrofuran (DHMTHF) in monophasic and biphasic reactor systems.

TL;DR: In this article, the authors highlight recent advances in the copolymerization of carbon dioxide (CO2) and epoxides (oxiranes) to produce polycarbonates with specific regard for catalysts designed to afford high selectivity for COPolymer versus cyclic carbonate formation.

TL;DR: In this paper, a new route to linear as well as cross-linked terpene-based non-isocyanate poly(hydroxyurethanes) and prepolymers derived from the cyclic limonene dicarbonate (CL) was reported.

TL;DR: The iodine catalyzed oxidative system for 3-sulfenylation of indoles with disulfides using DMSO as oxidant has been achieved under ambient conditions, providing a convenient and efficient method for the synthesis of 3-methine-based indoles in good to excellent yields and with high selectivity.

TL;DR: In this article, the conversion of epoxidized seed oils with carbon dioxide to form cyclic carbonates was catalyzed with tetra-butylammonium bromide (TBAB) and silica-supported 4-pyrrolidinopyridinium iodide (SiO2-(I)), which was readily recovered without requiring the conventional purification by solvent extraction of TBAB.

TL;DR: In this article, a range of solvent free conditions have been investigated with complete LA conversion obtained at temperatures as low as 25 °C with support provided by a variety of supported catalysts.

TL;DR: In this paper, a fully bio-based benzoxazine monomer, 3-furfuryl-8-methoxy-3,4-dihydro-2H-1,3-benzoxazine (Bzf), was successfully synthesized via a solventless method.

TL;DR: The impressive advantages of asymmetric organomulticatalysis are highlighted, the development of its development is examined, and detailed reactions based on the catalyst classes employed are presented, ranging from the very beginnings to the latest multicatalyst systems.

TL;DR: In this article, a magnetic nanoparticle supported dual acidic ionic liquid catalyst was synthesized by anchoring 3-sulfobutyl-1-(3-propyltriethoxysilane) imidazolium hydrogen sulfate onto the surface of silica-coated Fe3O4 nanoparticles.

TL;DR: In this paper, the Sn-Beta catalyst has been used to convert various pentoses and hexoses into methyl lactate, leading to the formation of methyl vinyl glycolate and methyl 2-hydroxy-4-methoxybutanoate.

TL;DR: Graphite oxide was found to be a highly efficient, reusable and cost-effective heterogeneous catalyst for the direct metal-free transformation of amines to afford the corresponding imines under mild and neat conditions with molecular oxygen as the terminal oxidant as discussed by the authors.