Showing papers by "Luis A. Rios published in 2017"

Carbonation of epoxidized castor oil: a new bio‐based building block for the chemical industry

Abstract: BACKGROUND Cyclic fatty carbonates can be obtained from epoxidized vegetable oils and CO2 under mild conditions. The main application of these bio-derivatives is the production of thermoset polymers and non-isocyanate polyurethanes. Castor oil has a different chemical structure from the other oils that have been used for carbonation. In this work, a kinetic model was developed for high CO2 pressure carbonation of epoxidized castor oil. RESULTS The highest epoxide group conversion (93%) was obtained at 130 °C and 480 min. However, the highest content of carbonate groups (1.5 carbonates/molecule) was obtained at 115 °C and 180 min. A kinetic model was proposed which included carbonation of epoxide as well as etherification of the oxirane ring as a competitive reaction. Both reactions were best fitted to pseudo-first-order kinetics. Activation energy of carbonation and etherification of the oxirane ring were estimated as 37.41 and 33.25 kJ mol−1, respectively. CONCLUSION Carbonated castor oil was produced from the epoxidized oil at 100–130 °C and a constant pressure of CO2 (0.5 MPa). Because of the polyfunctional character of the product, it could find applications as a monomer and as a synthetic building block for other bio-based chemicals. This product and the reaction pathway have not previously been disclosed. © 2016 Society of Chemical Industry

Producción de Diésel Renovable a partir de Aceite de Higuerilla mediante Catalizadores de Níquel-Molibdeno Soportados sobre Alúmina

Abstract: espanolSe sintetizaron dos catalizadores tipo Ni-Mo soportados sobre y-Al2O3, con diferentes contenidos masicos de los metales activos, y su actividad catalitica en el proceso de desoxigenacion de aceite de higuerilla fue evaluada y comparada con el desempeno obtenido con un catalizador comercial. Previo a las reacciones de desoxigenacion, los catalizadores fueron reducidos y sulfurados con H2S producido in-situ. Los catalizadores fueron caracterizados mediante DRX, adsorcion-desorcion de N2 a 77 K, XRF y TPR. Las pruebas cataliticas fueron llevadas a cabo en un reactor de alta presion (Parr, 500 mL), operando en modo semi-batch. El mayor rendimiento masico hacia diesel renovable (C9-C24) fue del 82.9% y se obtuvo con el catalizador sintetizado que contiene 4.5% NiO y 20% MoO3, evaluado a 350°C, 90 bares y una concentracion del 10%. Ademas, este catalizador, bajo estas condiciones, presento una conversion del 100% y las selectividades mas altas hacia C17 (54.4%) y C18 (20.9%), asi como una menor selectividad a craqueados (0.83%). EnglishCatalysts of Ni-Mo type with different content of active species (Ni,Mo) were synthesized and supported over y-alumina and their catalytic activity in the deoxygenation process of castor oil was evaluated and compared with that obtained with a commercial catalyst. Prior to deoxygenation reactions, the catalysts were reduced and sulfurated with H2S produced in-situ. The catalysts were characterized by XRD, N2 adsorption-desorption at 77K, XRF and TPR. The catalytic tests were carried out in a high-pressure reactor (Parr, 500 mL), operating in semi-batch mode. It was found that the highest mass yield to renewable diesel (C9-C24) was 82.9%, obtained with the synthesized catalyst containing 4.5% NiO and 20% MoO3 operating at 350 °C, 90 bars and 10% catalyst concentration. Besides, this catalysts exhibited 100% conversion and the highest selectivities to C17 (54.4%) and C18 (20.9%), as well as the lowest selectivity to cracked products (0.83%).

Ketalization of epoxidized methyl oleate using acidic resins

Abstract: BACKGROUND Fatty acid dioxolanes can be used as bioplasticizers or biolubricants, replacing petroleum-derived products. Dioxolanes can be obtained by reaction of epoxides or glycols with ketones under acidic conditions. Bronsted and Lewis acids have been reported as catalysts of the reaction. However, acidic resins have not been used so far. These heterogeneous catalysts offer high activity, reusability as well as low price. In this work, ketalization of epoxidized methyl oleate with acetone was evaluated using acidic resins (Dowex-50WX2, Amberlyst-15 and Amberlite-IR120) at low temperature (35–55 °C). RESULTS Total conversion of epoxide was obtained with Amberlyst-15, while a maximum conversion of 20% was afforded with Dowex-50WX2. However, Dowex-50WX2 was more selective to the dioxolane (max. 95% selectivity) than Amberlyst-15 (max. 76% selectivity). Amberlite IR120 afforded the lowest conversion of epoxide (max. 3%). The activation energy of the ketalization catalyzed with Amberlyst-15 was calculated as 12.53 kcal mol−1. CONCLUSION A new application of acidic resins in the ketalization of fatty epoxides at low temperatures was described. The effects of resin crosslinking and temperature were evaluated. Three kinds of products were detected: dioxolane, glycol and ketone. Several reaction pathways were proposed for ketalization over each resin. © 2016 Society of Chemical Industry

Bagazo de sorgo dulce: una alternativa para la producción de etanol de segunda generación en Colombia (Parte I)

Abstract: Each lignocellulosic material is a new terrain to be explored, therefore, the physical chemical characterization of these materials is a fundamental step for the biotransformation process. The lignocellulosic composition of sweet sorghum bagasse was determined, values close to values reported in the literature were found. Pretreatment technologies were explored with steam, mild acid hydrolysis, alkaline delignification, NH3 soaking, AFEX, ozonolysis and alkaline peroxide; Being that the alkaline delignification with NaOH is the best option to pre-treat this substrate. The lignin content was decreased by 52% and ethanol productivity of 0.87 g / Lh was obtained, which equates to a yield of 114 L of ethanol / Ton bagasse of pre-treated dry sweet sorghum.