Catalytic Oxidation with Air of Cyclohexanone to Dicarboxylic Acids on Synthetic Carbons. Effect of Supported Metals and Solvents

Abstract

The oxidation with air of cyclohexanone was conducted in the presence of synthetic carbons catalysts. The effect of carbon activation treatment (CO2 or air burnoff), phosphorus additive, platinum loading, and nature of the solvent (water or water/acetic acid mixture) were studied. Cyclohexanone oxidation at 140 degrees C yielded a mixture of C6, C5, and C4 dicarboxylic acids. Air activated carbons, including those containing phosphorus or those supporting platinum, resulted in a higher yield of adipic acid. The activity and selectivity was associated with the oxygenated functional groups, essentially carbonyl/quinone groups, created during air activation of the carbon. The incorporation of phosphorus into the carbon increased slightly the selectivity to 34.3%, probably because this additive increased the density of oxygenated functional groups. The deposition of platinum by impregnation and liquid-phase reduction with formaldehyde increased the reaction rate and improved the selectivity to adipic acid, where the highest figure was 38.8%. It was suggested that platinum contributed to molecular oxygen activation. In contrast platinum deposition by cationic exchange followed by reduction under H2 resulted often in a detrimental effect probably because the density of the oxygenated groups on carbon is decreased upon H2 reduction in the presence of platinum. When the oxidation of cyclohexanone was carried out in mixtures of water/acetic acid, the selectivity given by the different samples were quite close and generally smaller than those obtained in water which indicates that acetic acid interacts with the oxygenated surface functional groups responsible for the activity and selectivity. Oxidation experiments with methyl-labeled 4-methylcyclohexanone indicated that glutaric acid was produced by oxidative decarbonylation of both the C1 and C2 carbon atoms of the molecule.

Studies on the structural change of a reaction-controlled phase-transfer [π-C5H5NC16H33]3{PO4[WO3]4} catalyst during the selective oxidation of cyclopentene to glutaric acid with aqueous H2O2

“…Dicarboxylic acids, including glutaric acid, adipic acid, trimethyladipic acid and dodecanedioic acid, are essential feedstocks for the manufacture of polyamides, polyesters, plasticizers and lubricating oils [1]. The anhydrides, one of the monomer of LCD materials, are also synthesized from dicarboxylic acids.…”

Oxidation of cyclic ketones to dicarboxylic acids

“…The reactions were carried out in the presence of eg. : ruthenium or platinum supported on activated carbon 27, 29 , natural phosphate modifi ed by vanadium 28 , [Ru(H 2 O) 6 ] 2 (Me-C 6 H 4 -SO 3 ) 2 30 or commercially available Mn(NO 3 ) 2 /Co(NO 3 ) 2 /HNO 3 31 system as catalysts. For example, by carrying out the oxidation reaction with oxygen, in the presence of Re 2 (CO) 10 /Peg-400/K 2 CO 3 / KOH system, adipic acid, pimelic acid, cork acid, acelaic acid and 1,12-dodecanedioic acid were obtained from respective ketones with yields ranging from 74 to 89% (rt., 24-96 h) 26 .…”

Lennard-Jones force field parameters for cyclic alkanes from cyclopropane to cyclohexane

“…One methylene site was assigned to be at the origin of the coordinate system and the positions of other sites were calculated via Eq. (6). Note that the relations between the sometimes different site-site distances remained unchanged.…”

“…Cyclopentane is used as a blowing agent for polyurethane foams that are employed for thermal insulation purposes, e.g., in domestic refrigerators and freezers [5]. Cyclohexanone, obtained by oxidation of cyclohexane, is converted by means of catalytic oxidation with air into dicarboxylic acids, which are essential raw materials to yield polyesters, polyamides, plasticizers and lubricating oils [6].…”