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The production of biodiesel from soybean oil and ethanol was investigated in switchable-polarity solvent (SPS) media of DBU and ethanol. The highest biodiesel yield catalyzed by DBU could reach 97.9% under optimized conditions, i.e. ethanol-oil molar ratio: 12 : 1, DBU-oil molar ratio: 2 : 1, reaction temperature: 70 °C, reaction time: 2 h. According to the kinetic analysis, the reaction order of oil was estimated to be 0.7, the apparent activation energy was 16.763 kJ mol-1, the pre-exponential factor was 561.31 mol 0.3 mL-0.3 min-1 using the Arrhenius equation for the first time, which explains the high efficiency of the DBU catalyst. The DBU-catalyzed transesterification in the DBU-ethanol switchable-polarity solvent offered an interesting alternative, which would be used to simplify the transesterification and separation to a single step. [ABSTRACT FROM AUTHOR]

The aim of this paper was to develop a process for the production of DAG from butterfat through glycerolysis and short-path distillation and to evaluate the physical properties of the DAG in comparison with the original butterfat. Chemical glycerolysis produced a mixture of acylglycerols containing DAG together with MAG and TAG. From the mixture of glycerolysis products, MAG were removed through three consecutive distillations (vacuum < 0.001 mbar) at 150°C. TAG were separated from DAG by distillation at 210°C, which gave a product with more than 80% DAG in the distillates. Distillation temperatures had significant effects on acyl migration. The formation of desirable 1,3-DAG was favored at higher temperatures. Under 210°C distillation, the equilibrium ratio of 6:4 was obtained between 1,3-DAG and 1,2(2,3)-DAG. The FA profile of the DAG product was relatively similar to the original butterfat. The total DAG recovery was around 77% in the pilot-scale production. The different patterns of m.p. were observed between butterfat and the DAG fraction produced as well as the MAG fraction collected. Solid fat content profiles of the DAG fraction and its mixtures with rapeseed oil possessed trends similar to those of the corresponding butterfat and its mixtures with rapeseed oil. Compared with butterfat, the DAG fraction behaved differently in its thermal profiles, crystallization patterns, and rheological properties; for example, the dropping point was 13°C higher for the latter than for the former, and the crystal pattern was mostly β form for the latter, whereas the former was the β' form. [ABSTRACT FROM AUTHOR]