No abstract

No abstract

Methyl esters of fatty acids (also known as biodiesel) made from transesterification of vegetable oils and animal fats with methanol, have shown a lot of promise as alternative diesel fuels. Glycerol is the inevitable byproduct of transesterification process. While there are existing markets for glycerol, a significant increase in availability of glycerol, resulting from the expanded use of vegetable oils and animal fats, would destabilize the glycerol market. In this study, the synthesis of glycerol carbonate from glycerol and dimethyl carbonate was investigated. Glycerol carbonate is a key multifunctional compound employed as a solvent, additive, monomer and chemical intermediate. The resulting glycerol carbonate was obtained in almost quantitative yield. According to measured data a well-elaborated mathematical model of the reactor was used for experiments can be adequate to assign parameters of kinetic equations of the assumed reaction mechanism. Component mass balances were built into the reactor model and order of reactions was fixed.

Fine tuning of the catalytic activity of chiral bis(diarylphosphino)pentane ligands [cf. (I)] is presented by use of electronic effects of the aryl substituents. Catalytic activity of the ligands is tested in the Rh-catalyzed hydrogenation of α,β-unsaturated acids (II) and (IV). Best results for itaconate (II) are achieved with the less electron-rich catalyst (Ia), while enantioselectivity and activity decreases with introduction of methyl or methoxy groups. In contrast, for substrates bearing β-aryl substituents (IVb) -(IVd) the electron-rich dimethylphenyl-substituted catalyst (Ib) gives the best results. -(HERSECZKI, Z.; GERGELY, I.; HEGEDUES, C.; SZOELLOESY, A.; BAKOS*, J.; Tetrahedron: Asymmetry 15 (2004) 11, 1673-1676; Dep. Org. Chem., Univ. Veszprem, H-8201 Veszprem, Hung.; Eng.) -Mischke 42-047