Avaliação do MoO3 suportado em material micromesoporoso na reação de transesterificação do óleo de soja.

Abstract

The transesterification reaction of vegetable oils or animal fats for the biodiesel production has been highlighted because of the obligatory use of the biodiesel in diesel oil. And in the transesterification reaction a source of triglycerides, a short-chain alcohol and a catalyst with specific properties for the reaction are used. The development of heterogeneous micro-mesoporous type catalysts, which have both active acid sites and volumetric molecule accessibility stands out due to the union of different properties in a single material. The catalytic activation of those materials is performed through the metal incorporation on the hybrid structure, the molybdenum, for example, confers the formation of the acid sites of Lewis and Bronsted to the support. The objective of this research had been evaluated the molybdenum trioxide supported in the structure of MCM-22/MCM-41 micro-mesoporous material, in different conditions of soybean oil transesterification reaction for biodiesel production. The zeolite MCM-22 was obtained by the static hydrothermal method; the support MCM-22/MCM-41 was synthesized by the seed method, adding different percentages of MCM-22 to the MCM-41 synthesis gel; the MoO3 incorporation through impregnation by pore saturation and the transesterification reaction was performed in a batch reactor. The reactional variables were evaluated in relation to the percentage of esters converted by a factorial design of the type 2³ + 3PtCt and the transesterified products were characterized by density, viscosity and acidity level. In the diffractograms were identified the MCM-22 zeolite structure, the micro-mesoporous material MCM-22/MCM-41 and the peaks to MoO3. In the thermograms, the temperature of activation by calcination of the support and MoO3 was 550 °C. In the micrographs were found spherical particles involved by agglomerates of particles representing both the microporous phase and the mesoporous phase of the micro-mesoporous materials, and long stems relative to MoO3. According to the textural properties obtained by the BET method, a reduction of the parameters was observed by MoO3 incorporation. From the factorial design it was verified that the reaction using the catalyst with 15% of MoO3, temperature of 150 ° C and 3h of reaction, converted 100% of the triglycerides present in soybean oil to methyl esters, which specifies the oil obtained in biodiesel in accordance with the norm established by ANP Resolution No 45 of 8/25/2014. In relation to the characterizations that specify the transesterified oil as biodiesel, it was observed that the density, viscosity and acidity index tended to be within the parameters established by the resolution according to the percentage of converted esters. According to the statistical treatment in the obtained results it was confirmed that the reactional variables and the effects between them were significant in the response factor (% of methyl esters), being the time factor the one that more influence in the response variable.