This work presents the biofuel production results of the esterification of fatty acids (C12-C18) and high-acid-content waste vegetable oils from different soap stocks (soybean, palm, and coconut) with methanol, ethanol, and butanol by acid catalysis. We used Amberlyst-35 (A35) sulfonic resin as a heterogeneous acid catalyst and p-toluenesulfonic acid as a homogeneous catalyst for comparison. Both the heterogeneous (A35) and homogeneous (p-toluenesulfonic acid) reactions were performed with 5% w/w of catalyst. The final products were analyzed by proton nuclear magnetic resonance (1H NMR). The homogeneous catalyzed esterification of fatty acids with methanol, ethanol, and butanol produced esters with yields higher than 90%. In the reaction with fatty acids and methanol catalyzed by A35, the best results were achieved with lauric acid and methanol, with a yield of 97%. An increase in the hydrocarbon chain decreased the rate of conversion and yield for stearic acid with methanol, which was 90%. Maximum biodiesel production was achieved from coconut and soybean soap stocks and methanol (96%-98%), which showed conversions very close to those obtained from their respective fatty acids. Microwave irradiation reduced the reaction time from 6 to 1 h in the esterification reaction of fatty acids with butanol.

Commercial and synthetic mesoporous aluminas impregnated with potassium carbonate were characterized by X-ray diffraction (XRD), nitrogen physisorption, infrared spectroscopy and 27Al MAS NMR. The activities in the transesterification reaction of sunflower oil with methanol for biodiesel production were evaluated. 27Al MAS NMR spectra evidenced the presence of AlIV and AlVI in the samples, and also of AlV sites in the mesoporous synthesized alumina, which disappeared after impregnation with potassium salt followed by calcination. All aluminas containing potassium were active for biodiesel production from sunflower seed oil, with high conversions by both conventional heating and microwave irradiation.

A atividade catalítica de sólidos ácidos como o fosfato de nióbio e a Amberlyst 35, uma resina trocadora de íons, foi avaliada na acetalização do hexanal com 2-etil-hexanol. Foram avaliadas a concentração do catalisador e a temperatura de reação na conversão do hexanal. A possibilidade de re-utilização do fosfato de nióbio também foi estudada e evidenciou ser possível re-utilizar este catalisador sem perda da atividade. O rendimento em acetal foi acima de 90% em condições brandas de reação.

The catalyst activity of solid acids such as niobium phosphate and Amberlyst 35, an ion exchange resin, was evaluated in the acetalization of hexanal with 2-ethyl-hexanol. The catalyst loading and the reaction temperature were evaluated in the hexanal conversions. The possibility of recycling niobium phosphate was also studied, showing that it was possible to reuse this catalyst without significant loss in its catalytic activity. The yield in acetal was above 90% under mild conditions.

A atividade catalítica do fosfato de nióbio foi avaliada na reação de alquilação em fase líquida do anisol com 1-dodeceno, 1-octeno, 2-octanol e 1-octen-3-ol e na reação do fenol com 1-octen-3-ol. Melhores resultados foram alcançados na alquilação do anisol e do fenol com 1-octen-3-ol que produziu principalmente produtos monoalquilados. Na reação com o fenol e 1-octen-3-ol os principais produtos formados foram os octenil-fenóis (C-alquilação) e o fenil-octenil éter (O-alquilação). A reação favorece a formação de C-alquilados em relação aos O-alquilados.

The catalytic activity of niobium phosphate was evaluated in the liquid phase alkylation reaction of anisole with 1-dodecene, 1- octene, 2-octanol and 1-octen-3-ol and in the reaction of phenol with 1-octen-3-ol. Best results were achieved in the alkylation of anisole and phenol with 1-octen-3-ol that produced mainly monoalkylate products. In the reaction with phenol the major products formed were octenylphenols (C-alkylation) and phenyl-octenyl ether (O-alkylates). The reaction favors the formation of C-alkylates over O-alkylates.

Neste trabalho apresentamos os resultados da eterificação do glicerol com álcool benzílico, catalisada por diferentes sólidos ácidos. O mono-éter benzílico do glicerol foi o produto principal nas reações com a zeólita β e a resina ácida Amberlyst-35. Já o éter-di-benzílico foi o produto majoritário nas reações com o ácido p-tolueno-sulfônico e a argila K-10 como catalisadores. O ácido nióbico foi inativo na reação. A estrutura porosa da zeólita impediu a formação significativa de produtos de di e tri eterificação.

In this work we present the results of glycerol etherification with benzyl alcohol, catalyzed by different solid acids. The mono-benzyl-glycerol ether was the main product in the reactions catalyzed by β zeolite and Amberlyst-35 acid resin, whereas di-benzyl-ether was formed in higher yield with the use of p-toluene-sulfonic acid and K-10 montmorillonite as catalyst. Niobic acid was inactive in this reaction. The porous structure of the zeolite impaired the formation of di and tri-benzyl-glycerol ethers.

Foram estudados os efeitos da razão molar aromático/cloreto de alquila, adição de base, solvente e agente alquilante, na alquilação do etilbenzeno catalisada pela zeólita FeY. Ficou caracterizada a alquilação ocorrendo no interior dos poros da zeólita, uma vez que ela é pouco afetada pela razão molar dos reagentes. A adição de bases e solventes oxigenados, capazes de complexar com o sítio ativo, inibe a reação. Foi proposto um mecanismo envolvendo transferência de um elétron entre as espécies de ferro ativas e o cloreto de alquila, para explicar os resultados.

The effect of aromatic/alkylchloride molar ratio, base addition, solvent and alkylating agent on the ethylbenzene alkylation over FeY zeolite was investigated. It was shown that alkylation occurs inside the pores and it is little affected by the reactants molar ratio. On the other hand, addition of bases or oxygenated compounds, capable of complexing with the active site, blocks the reaction. A mechanism involving single electron transfer between the active iron species and the alkylchloride was propose to account for the results.

Diferentes suportes poliméricos à base de estireno (S) e divinilbenzeno (DVB) foram sintetizados e suas morfologias caracterizadas por microscopia óptica e eletrônica de varredura. Foram preparados e caracterizados catalisadores sulfônicos a partir desses suportes e suas atividades catalíticas foram avaliadas na transesterificação de óleo vegetal com metanol. Os resultados obtidos com esses catalisadores foram comparados com os produzidos com uma resina sulfônica comercial. Verificou-se que os catalisadores sintetizados neste trabalho apresentaram desempenhos próximos ao da resina comercial.

Different polymer supports based on styrene (S) and divinylbenzene (DVB) were synthesized and their morphology was characterized by optical and scanning electron microscopy. Sulfonic catalysts were prepared from these supports, characterized and their activities were evaluated in vegetal oil transesterification with methanol and compared with the performance of a commercial sulfonic resin. The synthesized catalysts showed results close to the commercial resin.

Três resinas catiônicas (Amberlyst 15, Lewatit SPC 112, ambas comerciais e MLS 07, sintetizada em laboratório) foram utilizadas como catalisadores em reação de alquilação. A resina MLS 07, obtida pela copolimerização em suspensão do estireno com divinilbenzeno, foi sintetizada de modo que apresentasse tamanho médio de partícula e porosidade próximos aos da resina Amberlyst 15. MLS 07 foi modificada por meio de reação de sulfonação dos anéis aromáticos, que introduziu no material, grupos ativos (SO3H). As três resinas, selecionadas em duas faixas granulométricas, foram caracterizadas por adsorção de nitrogênio (área específica, volume de poros e diâmetro médio de poro), por microscopia eletrônica de varredura (morfologia) e quanto a sua capacidade de troca iônica. Os catalisadores foram utilizados em reações de alquilação de tolueno com álcool benzílico. Foi observada a influência de parâmetros como: tamanho médio de partícula, morfologia, tipo de catalisador e temperatura na conversão do álcool benzílico e na seletividade da formação do produto de interesse, benziltoluenos (orto, meta e para). Os dados obtidos mostraram que as resinas Amberlyst 15 e MLS 07 apresentaram melhor performance quando comparadas com a Lewatit SPC 112 que apresentou menor atividade e seletividade no produto de interesse em todas as condições de reação utilizadas. Esse resultado pode ser atribuído principalmente à menor área específica desse material em relação às das outras duas resinas.

Three cationic resins (commercial Amberlyst 15 and Lewatit SPC112, and MLS 07, synthesized in our laboratory) were utilized as catalysts in alkylation reactions. MLS07 resin, prepared by suspension copolymerization of styrene and divinylbenzene, was produced in selected conditions in order to present average particle size and porosity close to those of Amberlyst 15. The SO3H active groups were introduced in the MLS07 resin by sulfonation of the aromatic rings. Samples of the three resins, of two granulometric ranges each, were charactherized by nitrogen adsorption (specific surface area, pore volume and average pore diameter), electron scanning microscopy (morphology) and by their ion exchange capacity. The catalysts were used in alkylation reactions of toluene with benzyl alcohol. The influence of parameters such as avarage particle size, morphology, catalyst type and reaction temperature on the conversion of the benzyl alcohol and on the reaction selectivity relative to the formation of benzyl-toluene, was sutdied. The data obtained show that Amberlyst 15 and MLS 07 presented better performance as compared to that of Lewatit SPC112. In all the reaction conditions employed Lewatit SPC 112 showed the lowest activity and selectivity in the formation of the desired product (o-, m-, p- benzyltoluene). This behavior may be mainly attributed to the fact that Lewatit SPC112 has the lowest surface area of the three resins.