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Heterogeneous continuous transformation of methyl levulinate (ML) and ethyl levulinate (EL) to γ -valerolactone (GVL), as a promising C 5 -platform molecule was studied at 100°C. It was proved that the H-Cube ® continuous hydrogenation system equipped with 5% Ru/C CatCart ® is suitable for the reduction of both levulinate esters. While excellent conversion rates (greater than 99.9%) of ML and EL could be achieved in water and corresponding alcohols, the selectivities of GVL were primarily affected by the solvent used. In water, 100% conversion and ca 50% selectivity that represent ca 0.45 mol GVL g metal −1 h −1 productivity towards GVL, were obtained under 100 bar of total system pressure. The application of alcohols as a solvent, which maintained high conversion rates up to 1 ml min –1 flow rate, resulted in lower productivities (less than 0.2 mol GVL g metal −1 h −1 ) of GVL. Therefore, from a synthesis point of view, the corresponding 4-hydroxyvalerate esters could be obtained even at a higher reaction rate. The addition of sulfonated triphenylphosphine ligand (TPPTS) allowed reduction of the system pressure and resulted in the higher selectivity towards GVL.

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The very first application of supercritical fluid extraction (SFE) on enantioseparation of alcohols is discussed. Resolution of three chiral alcohols (trans-2-chloro-cyclohexanol, trans-2-bromo-cyclohexanol, and trans-2-iodo-cyclohexanol) were performed by partial complexation with (-)-O,O'-dibenzoyl-(2R,3R)-tartaric acid monohydrate (DBTA). DBTA formed diastereomeric complexes with all S,S-enantiomers stable enough to extract the unreacted alcohols with supercritical carbon dioxide. Resolution efficiency increased with the size of halogen substituents, and by the proper selection of molar ratio, pure (-)-R,R-trans-2-iodo-cyclohexanol (ee > 99%, yield: 39%) or (+)-S,S-trans-2-iodo-cyclohexanol (ee = 98%, yield: 8%) were prepared in one process step. Achieved resolution efficiency values were much higher in all resolution procedures than in any other known enantioseparation of these racemic compounds. The developed method offers an environmentally friendly, efficient alternative of currently applied resolution processes, also on a preparative scale.

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Enzymatic kinetic resolution of racemic 1-phenylethanol catalyzed by immobilized Candida antarctica lipase B was investigated in a neat systems at the temperature range of 30-70°C. Synthetic triglycerides, namely glycerol triacetate and glycerol tributyrate, were applied as the esterification agents. Both esterification agents were efficient regarding to the enantioselectivity (>1000). Initial rate of reaction and the kinetic constants were influenced by the applied esterification agent significantly. A detailed modelling approach is presented and verified in the temperature range on 30-60°C for the tributyrin system.