Wilma A. Gonzalez

Catalytic decomposition of vegetable oil

Abstract Vapours of crude and prehydrogenated soybean oil were decomposed by passage over solid acid (Al 2 0 3 − n) and base (MgO) in a glass tubular reactor at 300–500°C. The liquid products were analyzed by infrared spectroscopy and gas chromatography. The degree of unsaturation of the oil was found to have a dominant effect on the products. Soybean oil prehydrogenated to a low iodine value of 10 yields essentially pure hydrocarbon products with a mean molecular weight comparable to that of diesel oil, while crude soybean oil yields a mixture of oxygen containing products and hydrocarbons of lower mean molecular weight. These observations were compared to catalytic decomposition of stearic and oleic acids under similar conditions.

H3PO4/Al2O3 catalysts: characterization and catalytic evaluation of oleic acid conversion to biofuels and biolubricant

Al2O3 and H3PO4/Al2O3 catalysts were investigated in the conversion of oleic acid to biofuels and biolubricant at 1 atm and at 623 K. The catalytic tests were performed in a fixed bed and continuous flow reactor, using an oleic acid-catalyst ratio of 4 and N2 as the carrier gas. The reaction products were analyzed by gas chromatography and acidity measurements. N2 adsorption-desorption, X ray diffraction, 31P nuclear magnetic resonance and FT-IR spectroscopy were also employed to evaluate the textural, structural and acidic properties of the catalysts. The results showed that phosphoric acid impregnation improved the alumina decarboxylation activities, generating hydrocarbons in the range of gasoline, diesel oil and lubricant oil. The best catalytic performance was achieved with the highest surface area alumina impregnated with H3PO4, which was the solid that allied high total acidity with a large quantity of mesopores.

Benzylation of toluene and anisole by benzyl alcohol catalyzed by niobic acid: influence of pretreatment temperature in the catalytic activity of niobic acid

Abstract We have studied the influence of the pretreatment temperature (423 K and 573 K) on the catalytic activity of commercial niobic acid for the benzylation of toluene and anisole with benzyl alcohol. The reactions were carried out in liquid phase at reflux temperature of the mixture. Best results were achieved with niobic acid pretreated at 573 K, The conversion of benzyl alcohol was 78.9 to anisole and the main product was the monobenzylation product.

Cracking and hydrocracking of triglycerides for renewable liquid fuels: alternative processes to transesterification

Os processos industriais mais utilizados na producao de combustiveis liquidos semelhantes ao diesel usam catalisadores homogeneos basicos atraves das metanolise e etanolise de oleos tais como os de soja, canola, palma entre outros. Desse modo, se obtem o biodiesel. Por sua vez, transformacoes termo-cataliticas usando as facilidades existentes nas refinarias de petroleo sao alternativas que merecem atencao devido a sua viabilidade economica. De fato, tres processos industriais ja estao em funcionamento e novos projetos estao em fase final para comercializacao. O presente trabalho analisa os experimentos ja realizados por pesquisadores brasileiros nas areas do craqueamento, do craqueamento catalitico e do hidrocraqueamento catalitico dos oleos vegetais puros ou modificados. A partir dos resultados descritos, sao sugeridas novas direcoes destas pesquisas para os proximos anos. The most used industrial processes for the production of liquid fuels like diesel type are based on the methanolysis and ethanolysis of various oil reactants, such as palm, soybean and rapeseed oils, in the presence of homogeneous base catalysts. However, thermal and catalytic transformations of vegetable oils using available reactors and industrial processes are possible alternatives and deserve attention. In fact, three industrial processes are operating and new projects are announced. The present work analyses the experimental studies performed up to now by Brazilian researchers in the field of cracking, catalytic cracking and hydrocracking of pure or modified vegetable oils. From the published results, some research areas for the near future are suggested.

Aqueous-phase oxidation of 5-hydroxymethylfurfural over Pt/ZrO2 catalysts: exploiting the alkalinity of the reaction medium and catalyst basicity

Abstract The basicity required for the aqueous-phase selective oxidation of 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid (FDCA) is explored through different approaches. Homogeneous hydroxides were tested along with a Pt/ZrO2 catalyst to establish a benchmark with widespread literature. Insoluble hydroxides were then taken to evaluate the behavior of dual metal/base heterogeneous catalytic systems. Finally, an attempt to bring such alkalinity to a bifunctional catalyst was investigated by using ZrO2-based solid solutions as supports. Mg, Ca, Y, and Ti were used as dopants. It was seen that a moderate alkali solution leads to 70% yield to FDCA. Equivalent yields are achieved by replacing homogeneous alkali by poorly soluble Mg(OH)2 in a heterogeneous system. Performing aqueous-phase oxidation under base-free conditions on ZrO2-doped supported catalysts indicated that the production of FDCA is associated with the reaction pH imposed by the bifunctional catalyst itself. Among the studied dopants, Mg-containing catalysts were the ones capable of promoting selective oxidation. However, it is shown that hosting Mg into the ZrO2 crystalline structure does not prevent leaching upon reaction in an aqueous medium.

Reutilization of Glycerol Derived from Biodiesel Production Using HPW- Based Catalysts Supported on Niobium for Obtention of Additives

This review proposes the use of residual glycerol, generated in biodiesel production, as raw material for production of oxygenate additive to biofuel. Oxygenated additives, such as glycerol ethers, increase the value of fuel mixture and engine performance. This represents a new methodology in line with the green chemistry principles. The etherification reaction, responsible for the additives production (glycerol ethers), can be effected by the heterogeneous acid catalysts application due to their specificities, like the possibility of reusing, greater strength and higher acidity. It was found that the Keggin heteropolyacids (HPW) supported on niobia have a potential that can be exploited for further industrial application.

On the Effect of Dopants to Control the Structure of Vanadium Phosphate Oxides for the Mild Oxidation of N-Butane to Maleic Anhydride

Doping (VO)2P2O7 catalyst by niobium affects its structure : the material is less crystallized and develops defects at the periphery of the crystals which are responsible for the increase of the nbutane conversion for the mild oxidation to maleic anhydride.