The objective of this work was to study the synthesis of ethyl esters via esterification of soybean oil deodorizer distillate with ethanol, using solid acid catalysts and commercial immobilized lipases, in a solvent-free system. Three commercially immobilized lipases were used, namely, Lipozyme RM-IM, Lipozyme TL-IM, and Novozym 435, all from Novozymes. We aimed for optimum reaction parameters: temperature, enzyme concentration, initial amount of ethanol, and its feeding technique to the reactor (stepwise ethanolysis). Reaction was faster with Novozym 435. The highest conversion (83.5%) was obtained after 90 min using 3 wt.% of Novozym 435 and two-stage stepwise addition of ethanol at 50 degrees C. Four catalysts were also tested: zeolite CBV-780, SAPO-34, niobia, and niobic acid. The highest conversion (30%) was obtained at 100 degrees C, with 3 wt.% of CBV-780 after 2.5 h. The effects of zeolite CBV 780 concentration were studied, resulting in a conversion of 49% using 9 wt.% of catalyst.

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The thermal cracking of a vacuum residue from a Brazilian refinery was studied in a continuous pilot plant. Reaction runs were carried out at 440–520 °C, 446–1825 kPa, and space times of 23–69 s. Reaction products were lumped into gas, naphtha, light gas oil (LGO), and heavy gas oil (HGO). The increase of the reaction pressure increased the residue conversion and the product yields. A power law kinetic modeling of the experimental data was performed, comprising first-order irreversible reactions. Two reaction schemes were evaluated: the first scheme consisted of four parallel reactions (one for each product lump), and the second scheme included the consecutive conversion of HGO in LGO. Kinetic parameters were estimated taking into account the experimental error. In the parallel-reaction scheme, almost all estimated parameters were statistically significant (except for the small gas formation at the highest pressure). The LGO and HGO formation reactions presented lower activation energies and higher rate constants. Inclusion of the consecutive reaction led to parameters without statistical significance for all reaction conditions. Furthermore, empirical correlations from the literature were fitted to the product yield data as a function of the process severity. The severity index was modified to include the effect of pressure explicitly, providing a slight improvement of the correlations.

Estolides are vegetable-oil-based lubricants obtained from oleic acid or any source of hydroxy fatty acids. In this work, the estolides synthesis from oleic acid and methyl ricinoleate (biodiesel from castor oil), using immobilized commercial lipases (Novozym 435, Lipozyme RM-IM, and Lipozyme TL-IM) in a solvent-free medium was investigated. Acid value was used to monitor the reaction progress by determining the consumption of acid present in the medium. Novozym 435 showed the best performance. Water removal improved the conversion. Novozym 435 was more active at atmospheric pressure. Novozym 435 was reused four times with conversion reaching 15% after the fourth reaction at 80°C. Estolides produced under the reaction conditions used in this work presented good properties, such as, low temperature properties as pour point (−24°C), viscosity (23.9 cSt at 40°C and 5.2 cSt at 100°C), and viscosity index (153).

The aim of this study was to produce monolaurin utilizing a commercial immobilized lipase (Lipozyme IM-20; Novo Nordisk, Bagsvaerd, Denmark) through the direct esterification of lauric acid and glycerol in a solvent-free system. The influence of fatty acid/glycerol molar ratio, temperature, and Lipozyme (IM-20) concentration on the molar fraction of monolaurin were determined using an experimental design. The best conditions employed were 55 degrees C, lauric acid/glycerol molar ratio of 1.0, and 3.0% (w/w) enzyme concentration. The final product, obtained after 6 h of reaction, was 45.5% monolaurin, 26.8% dilaurin, 3.1% trilaurin, and 24.6% lauric acid. The reusability of the enzyme was also studied.