Carboxylic acid

About: Carboxylic acid is a research topic. Over the lifetime, 48544 publications have been published within this topic receiving 605696 citations.

Non‐Pincer‐Type Manganese Complexes as Efficient Catalysts for the Hydrogenation of Esters

Abstract: Catalytic hydrogenation of carboxylic acid esters is essential for the green production of pharmaceuticals, fragrances, and fine chemicals. Herein, we report the efficient hydrogenation of esters with manganese catalysts based on simple bidentate aminophosphine ligands. Monoligated Mn PN complexes are particularly active for the conversion of esters into the corresponding alcohols at Mn concentrations as low as 0.2 mol % in the presence of sub-stoichiometric amounts of KOtBu base.

2,2-dimethyl-{11 -aryloxy-alkanoic acids and salts and esters thereof

Abstract: A series of 2,2-dimethyl- omega -phenoxyalkanoic acids and 2,2dimethyl- omega -(disubstituted phenoxy)alkanoic acids having 3 to 6 methylene groups between the phenoxy group or 0 phenoxy group and the carbon atom substituted by two methyl groups; and their salts and esters. The compounds reduce serum triglyceride levels and can be produced by (a) reacting an alkali metal derivative of an isobutyric acid, salt, or ester with a phenoxyalkyl halide or a disubstituted phenoxyalkyl halide; (b) esterifying a carboxylic acid; or (c) hydrolyzing a carboxylate ester.

Quantification of monocarboxylic acids in the Murchison carbonaceous meteorite

Abstract: The abundances of some of the straight- and branched-chain isomers of the monocarboxylic acids found in the Murchison carbonaceous chondrite are determined. Monocarboxylic acids extracted from a crushed sample of Murchison interior were quantified by means of gas chromatography and mass spectroscopy after a spiking solution of deuterated analogues of 11 carboxylic acids had been added. Monocarboxylic acid abundances are found to range between 1.83 and 0.01 micromole/g, which is significantly higher than Murchison amino acid concentrations, and to decrease with increasing carbon number for both branched and unbranched molecules. The results are interpreted to support the abiotic extraterrestrial synthesis of monocarboxylic acids. Possible mechanisms leading to the equal synthesis of branched and each unbranched carboxylic acid with the same carbon number are considered, noting that the Fischer-Tropsch Type mechanism by itself is incapable of accounting for the observed distributions.

Quantifying Ligand Exchange Reactions at CdSe Nanocrystal Surfaces

Abstract: The exchange reactions of X-type ligands at the surface of CdSe nanocrystals have been quantified via 1H NMR, absorbance, and emission spectroscopies. 1H NMR was used to quantify displacement reactions of oleate-capped CdSe nanocrystals with carboxylic-acid-, phosphonic-acid-, and thiol-terminated ligands that incorporate terminal alkene functionalities. The alkenyl protons of the native oleate ligand and the vinylic protons of the exchange ligand provide spectroscopic handles to quantify both free and surface-bound forms of these ligands. Undec-10-enoic acid was found to undergo an exchange equilibrium with oleate (Keq = 0.83), whereas phosphonic-acid- and thiol-terminated ligands irreversibly displace native oleate ligands. Absorption and emission experiments indicate that the carboxylic acid exchanges occur solely between surface-bound ligands, whereas exchange reactions with phosphonic acids and thiols alter the surface metal atoms of the nanocrystals, presumably through the displacement of Cd(oleate)...