Nanosized and reusable SiO2/ZrO2 catalyst for highly efficient biodiesel production by soybean transesterification

Abstract

O catalisador nanoestruturado SiO 2 /ZrO 2 foi preparado pelo método sol-gel e apresentou uma área superficial de 131,50 ± 14 m 2 g-1. As imagens de microscopia eletrônica de varredura mostraram que o catalisador apresentou partículas muito homogêneas de 250 nm de diâmetro. Este material foi aplicado na transesterificação do óleo de soja para a produção de biodiesel. A conversão do óleo em biodiesel teve um rendimento de 96,2 ± 1,4 % em 3 h de reação de transesterificação catalisada pelo material SiO 2 /ZrO 2 (SiZr). O catalisador foi recuperado e reutilizado por seis vezes, mantendo uma eficiência catalítica de 84,1%. Nanosized SiO 2 /ZrO 2 catalyst with high surface area (131.50 ± 14 m 2 g-1) was prepared by the sol-gel method. The material presented highly homogeneous particles with an average diameter of 250 nm according to SEM images. It was applied in the transesterification of soybean oil for biodiesel production. The biodiesel conversion reached a yield of 96.2 ± 1.4 % after 3 h of transesterification reaction catalised by SiO 2 /ZrO 2 (SiZr). The catalyst was recovered and reused six times, maintaining a catalytic efficiency of about 84.1 %.

Aspects of protonation and deprotonation of humic scid durface on molecular conformation

“…This analysis showed the isotherms behavior and the absence of hysteresis which characterize the HA as a microporous material. 14,18,19 HA samples also presented a low surface area, which gave 0.52, 0.48 and 0.71 m 2 g -1 for CHA, PHA and AHA. This result is in agreement with the values reported before.…”

“…At a low pH value, the groups are protonated and at high pH values, neutralization reactions take place and the groups dissociate, becoming negatively charged. 18,19 The comprehension of pH dependence on charge behavior around surfaces is important in order to control the colloidal stability of dispersion. Around a charged surface in aqueous solution, a diffuse electric double layer takes place, which protects the charge and let all the system uncharged.…”

Development of a lewis-based catalytic system for biodiesel production: from a batch laboratory scale to a continuous pilot plant

“…After trying some strong basic 25 and acid 26,27 Lewis catalysts, we decided also to focus on mild Lewis acid metal compounds, which were fairly studied for this process.…”

Metal-cellulose catalytic systems for biodiesel preparation and reductive stabilization

“…Note that these Lewis base catalysts have been further anchored in more expensive inorganic materials behaving similar activities. [25][26][27] The pioneering studies by Schuchardt et al on modified cellulose as a catalyst for transesterification of vegetable oils inspired us to prepare a new catalytic system with metal centers anchored on the modified cellulose, to be applied in various attractive organic reactions for biorefinery. In this work,we present the oxidation of cellulose to obtain carboxylic groups and the coordination of metal cations, such as tin, nickel and palladium, and the use of these catalytic systems in biodiesel production and partial hydrogenation.…”