Claudiney Soares Cordeiro

Catalisadores heterogêneos para a produção de monoésteres graxos (biodiesel)

The recent increase in the world biodiesel demand, along with the need to reduce costs while improving the environmental sustainability of the entire biodiesel production chain, have led to the search for heterogeneous catalysts that would be efficient and highly amenable to recycling. Many classes of materials have been tested for these purposes. Among these are zeolites, ion-exchange resins, inorganic oxides, guanidines, metal complexes, layered compounds and ionic liquids. This review article describes the structure, properties, synthesis and performance of compounds that are catalytic active in both esterification and transesterification reactions.

Layered metal laurates as active catalysts in the methyl/ethyl esterification reactions of lauric acid

In this work we report the synthesis, characterization and investigation of the catalytic activity of layered copper(II), manganese(II), lanthanum(III) and nickel(II) laurates in the methyl and ethyl esterification reactions of lauric acid. In the methyl esterification, conversions between 80 and 90% were observed for all catalysts, while for the ethyl esterification only manganese laurate showed reasonable catalytic activity, with conversions close to 75%. Reuse of copper and lanthanum laurates in three cycles of reaction was also investigated and both catalysts preserved the structure and retained catalytic activity close to that observed for the first reaction cycle.

LDHs Instability in Esterification Reactions and Their Conversion to Catalytically Active Layered Carboxylates

Layered double hydroxides (LDH) containing Zn/Al and Mg/Al with different counter-ions and M2+/M3+ ratios were synthesized and used as catalysts in the esterification of fatty acids with methanol. High conversion rates were obtained depending on the reaction conditions. However, LDHs were also converted in situ into layered carboxylates and this new material was responsible for the observed catalytic activity, which was preserved even after several consecutive reuse cycles.Graphical AbstractXRD patterns (A) and FTIR spectra (B) of synthetic LDHs.

Applications of Heterogeneous Catalysts in the Production of Biodiesel by Esterification and Transesterification

Abstract The development of solids with suitable catalytic properties has been one of the main drivers for the development of sustainable heterogeneous catalytic processes for the conversion of renewable resources in different forms of liquid biofuels such as biodiesel, bio-oils and synthetic hydrocarbons. The search for such catalytic processes is also listed as one of the main drivers for the development of green chemistry. However, heterogeneous solid catalysts are usually more expensive and less effective than homogeneous catalytic systems but they may offer other advantages such as selectivity, recyclability, low toxicity, easily handling and processing as well as a lower environmental impact due to the reduction of process wastes and effluents. This chapter describes a series of heterogeneous catalytic processes that are currently available for biodiesel production. Structural details of these catalysts are described along with their catalytic performance in both esterification and transesterification reactions.

Metal glycerolates as catalysts in the transesterification of refined soybean oil with methanol under reflux conditions

Divalent metal glycerolates were synthesized and investigated in the methyl transesterification of refined soybean oil. Higher conversions to monoacylesters were obtained for strontium and barium monoglycerolates and calcium diglycerolate. Calcium diglycerolate was shown to be stable up to a third reuse cycle, decomposing to an inactive mixture of CaCO3 and Ca(OH)2.

ESTERIFICAÇÃO E TRANSESTERIFICAÇÃO SIMULTÂNEAS DE ÓLEOS ÁCIDOS UTILIZANDO CARBOXILATOS LAMELARES DE ZINCO COMO CATALISADORES BIFUNCIONAIS

Palm oil containing 40% fatty acids was converted to methyl esters using zinc carboxylates as the esterification/transesterification catalyst. The reaction was optimized using a factorial design in which the effects of the alcohol:fatty acids molar ratio (MRAG) and the catalyst concentration (CAT) were assessed. The best conversion was achieved with CAT at 4 wt% and MRAG at 4:1. However, the solid catalyst presented significant structural changes after use. For instance, laurate anions were replaced by carboxylates of higher molecular mass, leading to the formation of a new catalytically active layered structure. Also, the glycerin obtained as a co-product contained 86 wt% glycerol.

Biodiesel: Matérias-Primas, Tecnologias de Produção e Propriedades Combustíveis

The entire biodiesel production chain developed tremendously in regions all over the world and this biofuel has established itself as one of the main alternatives to replace petroleum-derived fuels. Several studies have already demonstrated its compatibility with diesel oil and the international standards have evolved to ensure safety and satisfaction to the end-users. Although already losing priority in stronger economies such as United States, Germany and France, this production chain is still expanding considerably in emerging economies such as Brazil, where it has been established as a project of great scientific, technological, political and economic interests. In this article, important aspects of the biodiesel production and use are revised in detail, particularly in relation to the availability of suitable raw materials in large scale as well as to the chemistry involved in the technologies available to date for its conversion to biofuels that are fully compatible with diesel fuel applications.

Avaliação da natureza da atividade catalítica de compostos de bismuto em reações de metanólise do óleo de soja

Sodium bismuthate dihydrate and two species derived from its thermal treatment were investigated as catalysts for soybean oil methanolysis and, regardless of the type of solid used, ester yields always above 76 wt% were obtained. After a single reaction course, both liquid and solid phases were characterized using several analytical methods such as X-ray diffraction and thermogravimetric analysis. As a result, the catalytic phenomenon was shown to be solely due to the leaching of alkalinecatalytic species from the solid materials.

SIMULTANEOUS ESTERIFICATION AND TRANSESTERIFICATION OF ACID OILS USING LAYERED ZINC CARBOXYLATES AS BIFUNCTIONAL CATALYSTS

Palm oil containing 40% fatty acids was converted to methyl esters using zinc carboxylates as the esterification/transesterification catalyst. The reaction was optimized using a factorial design in which the effects of the alcohol:fatty acids molar ratio (MRAG) and the catalyst concentration (CAT) were assessed. The best conversion was achieved with CAT at 4 wt% and MRAG at 4:1. However, the solid catalyst presented significant structural changes after use. For instance, laurate anions were replaced by carboxylates of higher molecular mass, leading to the formation of a new catalytically active layered structure. Also, the glycerin obtained as a co-product contained 86 wt% glycerol.