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In this work, an efficient and green glycerolysis reaction catalyzed by zinc glycerolate was developed to prepare biodiesel from oleic acid. The active phase of zinc glycerolate was investigated by XRD, FTIR, 1H NMR, and 13C NMR. An interesting result was obtained that zinc glycerolate was first dissolved to form zinc oleate and then regenerated to zinc glycerolate during the reaction, which was essential for the conversion of oleic acid. The relationship between dissolved zinc glycerolate and conversion of oleic acid was determined. The regeneration of zinc glycerolate was achieved when the molar ratio of glycerol to oleic acid was higher than 0.6:1. A plausible pathway for the glycerolysis reaction catalyzed by zinc glycerolate was proposed. Zinc glycerolate could be recycled 10 times with no obvious decrease in catalytic activity, and the oleic acid conversion of 98% was achieved. In addition, zinc glycerolate was applied to catalyze glycerolysis reaction of different feedstock and demonstrated excellent performance. The results show that zinc glycerolate is a promising catalyst in glycerolysis reaction for biodiesel production. [Display omitted] [ABSTRACT FROM AUTHOR]

Desulfurization is important to the enhancement of biodiesel quality. In this study, the effects of reactant and catalyst addition and operations conducted on sulfur content at each stage during the biodiesel preparation process were examined. Based on the results of sulfide qualification and quantification, a high vacuum distillation method was developed to remove the sulfides in crude biodiesel. Biodiesel was separated into different fractions based on the boiling point and the sulfur content of each fraction was determined. Experimental results showed that most sulfides were distilled out with light and heavy fractions. Intermediate fraction was separated from the other fractions, resulting in high quality biodiesel with low sulfur content. The total yield of distillation fractions with sulfur content lower than 10 ppm reached 84.1%. A set of distillation facility with capacity of 10 m3/h was designed and developed accordingly for large-scale tests. The yield of low-sulfur biodiesel was around 83%, close to that obtained in the laboratory studies. In addition, economic analysis showed that the distillation facility can make revenue of more than $1.8 million per year, indicating that high vacuum distillation is economically feasible and promising for biodiesel desulfurization, especially in industrial application. Image 104946 • A high vacuum distillation method was proposed to remove sulfides in crude biodiesel. • Sulfides in crude biodiesel were qualitatively and quantitatively analyzed. • The total yield of biodiesel with sulfur content lower than 10 ppm was 84.1%. • Distillation facility with capacity of 10 m3/h was developed for large-scale tests. • The process is economically feasible for low-sulfur biodiesel production. [ABSTRACT FROM AUTHOR]

Trimethylolpropane fatty acid triester (TFATE) is a promising biolubricant as an environmentally friendly substitute to conventional mineral-based lubricants. However, the issues of extensive energy consumption from vacuum maintenance and feedstock saponification caused by strong alkaline catalysts exist in current TFATE-based biolubricant synthesis. Here, sustainable production of biolubricant was achieved with methyl oleate (MO) from non-edible oil sources as the feedstock and moderate alkaline K 2 CO 3 as the catalyst. Nitrogen gas stripping method instead of vacuum was adopted for methanol removal. The effects of agitation speed, N 2 flow rate, catalyst amount, MO to trimethylolpropane (TMP) molar ratio and temperature on MO conversion and TFATE selectivity were examined. The TFATE selectivity reached 95.6% under the optimized conditions. Leaching tests indicated neglectable K 2 CO 3 dissolution in reaction products. The kinetic parameters for the three consecutive transesterification reactions were calculated. In addition, the synthesized biolubricants exhibit low acid value and volatility, moderate iodine value, superior thermal stability, and good rheological and frictional properties. [Display omitted] • Biolubricant TFATE was produced by methyl oleate transesterification over K 2 CO 3 catalyst. • Nitrogen gas stripping method instead of vacuum was adopted for methanol removal. • The TFATE selectivity reached 95.6% under the optimized conditions. • Kinetic parameters for three consecutive transesterification reactions were calculated. • Products show superior thermal stability and good rheological and frictional properties. [ABSTRACT FROM AUTHOR]