Yoko Usui

A green method of adipic acid synthesis: organic solvent- and halide-free oxidation of cycloalkanones with 30% hydrogen peroxide

Cyclohexanone and cyclohexanol are oxidized to adipic acid in high yield with aqueous 30% H2O2 in the presence of H2WO4 as a catalyst under organic solvent- and halide-free conditions. It is important that no solvent is used in order to achieve high reactivity in this heterogeneous reaction. The use of t-butyl alcohol or dioxane as a solvent (homogeneous conditions) significantly decreases the yield of adipic acid from cyclohexanone. This ketone-to-dicarboxylic acid conversion is applicable to five- to eight-membered cyclic ketones. No operational problems are foreseen for a large-scale version of this green process.

Microalgal cultivation in a solution recovered from the low-temperature catalytic gasification of the microalga

Microalgal cultivation in a solution recovered from the low-temperature catalytic gasification of the microalga itself was studied. The growth of Chlorella vulgaris in 75-300-fold diluted recovered solution containing phosphate, magnesium ions and micro-elements was comparable to that in the standard culture medium. It was suggested that C. vulgaris could use ammonium in the recovered solution as its nitrogen source and at the same time could provide a source of biomass which was recycled via gasification.

Chemoselective Oxidation of Alcohols by a H2O2–Pt Black System under Organic Solvent‐ and Halide‐Free Conditions

Environmentally benign oxidation of allylic alcohols by platinum black catalyst with aqueous hydrogen peroxide to give the corresponding alpha,beta-unsaturated carbonyl compounds in high yield is presented. Reactions are carried out under organic solvent- and halide-free conditions. The platinum black catalyst is commercially available and is found to be reusable at least seven times before significant loss of catalytic activity. The operation is very simple, even in a hectogram-scale synthesis, and gives corresponding carbonyl compounds in over 90 % yield. The effective oxidation of benzyl and secondary alcohols are also described.