Influence of rare earth elements in the catalytic properties of hydrotalcites derivatives oxides for ethyl biodiesel

Author(s)

Jessika de Souza Rossi

• Document type: Master's Dissertation
• Press: São José do Rio Preto. 2016-04-19.
• Institution: Universidade Estadual Paulista (Unesp). Instituto de Biociências Letras e Ciências Exatas. São José do Rio Preto
• Defense date: 2016-02-25
• Advisor: Mauricio Boscolo

Abstract

On increasing national production, the industrial biodiesel synthesis occurs by transesterification in the presence of alkaline homogeneous catalysts. Although this process presents high yield, additional steps of purification of the product and the possibility to occur saponification make new ways of biofuels production are developed, such as heterogeneous catalysis. Among the studied materials for catalysts function there are mixed oxides of magnesium and aluminum from hydrotalcites calcination which may be doped with various metals to improve their catalytic activity. This paper aimed to study the mixed oxide characteristics from hydrotalcites doped with lanthanides. Thus, the discussion of the results were divided into two chapters. The chapter 2 shows the effects of the ions La, Ce and Lu in the amount of 1.0 to 2.0% promoted on the physicochemical properties of the hydrotalcites and the catalytic activity of the oxides in the production of biodiesel. The transesterification reaction was carried out using soybean oil and ethanol (ratio 1:20 w/w oil/ethanol) and catalyst 20% (mass catalyst/oil mass) at 120°C for 14 hours. The oxides doped with 1.0% had higher income than ones doped with 2.0%, and MgAl1La MgAl1Lu being the highest yields with 80 and 84%, respectively. In the Chapter 3 is reported the effect that the use of high-frequency energy such as microwaves and ultrasound have led to the structure, texture and quality of the crystals of solids. Thus, three series of hydrotalcites with 5.0% lanthanides (La, Ce, Yb, Lu) were prepared by co-precipitation (conventional synthesis) co-precipitation assisted by ultrasound and co-precipitation followed by treatment with microwave. The materials were characterized by the X-ray diffraction (XRD), the infrared spectroscopy (ATR-FTIR) and the analysis of the specific surface area by N2 adsorption. For the solids that involve La and Ce, large radius ions, there was segregated phase formation, however, the use of ultrasound and microwaves significantly improved the insertion of these metals lamellar lattice of hydrotalcites, beyond the increase of the surface area of the oxides. (AU)

• FAPESP's process: 14/20504-6 - Influence of rare earth elements in the catalytic properties of hydrotalcites and their oxides for ethyl biodiesel production
• Grantee: Jessika de Souza Rossi
• Support Opportunities: Scholarships in Brazil - Master