While criteria pollutants have established emission limits for motorcycles in Brazil, aldehydes limits have not been established and conclusive studies have not been found in the existing literature, despite the growing number of motorcycles using flex fuel in Brazil. This work presents results for the emissions of criteria pollutants, such as carbon monoxide, hydrocarbons and nitrogen oxides, acetaldehyde and formaldehyde. The motorcycle was tested with 22, 61, and 100% of ethanol in gasoline blends. Fourier transform infrared (FTIR) and high performance liquid chromatography (HPLC) were used to determine the pre- and post-catalytic converter emissions. Aldehyde emissions directly increased with the ethanol content in the fuel blend. The tailpipe aldehyde emissions for 22, 61, and 100% of ethanol in gasoline were 3.9, 8.5, and 38.8 mg km-1, respectively. These results demonstrated that aldehyde emissions in motorcycles are not negligible, and higher emissions are observed during the cold phase of the engine.

O biodiesel é um biocombustível biodegradável e não tóxico produzido a partir de recursos renováveis. Sua produção industrial ocorre pela transesterificação catalítica de óleos vegetais refinados com metanol ou etanol. Os custos de produção do biodiesel podem ser reduzidos pelo uso de matérias-primas não refinadas, cujos preços são inferiores aos dos óleos vegetais refinados. Neste trabalho estudou-se o uso de sulfato de estanho(II) (SnSO4), como catalisador para a transesterificação e esterificação simultânea de matérias-primas modelo com altos teores de ácidos graxos livres. Analisou-se a influência de parâmetros experimentais, a lixiviação do catalisador bem como a sua capacidade de reutilização. Obteve-se rendimento elevado (92%) para uma matéria-prima modelo contendo 70% (m/m) de ácidos graxos livres (ácido oleico), a 100 ºC, sob pressão autógena, 5% (m/m) de SnSO4 em excesso de etanol, após 3 h de reação. O catalisador foi reutilizado por dez vezes sem decréscimo significativo no rendimento de biodiesel.

Biodiesel is an alternative biodegradable and non-toxic biofuel produced from renewable resources. Industrially, it is produced by catalytic transesterification of refined vegetable oil with methanol or ethanol. Biodiesel production costs can be reduced by using non-refined feedstocks whose market prices are lower than those of refined vegetable oils. This work studied the use of tin(II) sulfate (SnSO4), as catalyst for the simultaneous transesterification and esterification of model acid oil containing high levels of free fatty acids. The influence of experimental parameters, catalyst leaching as well as its reusability was investigated. For a model feedstock containing 70 wt. % of free fatty acids (oleic acid), the highest biodiesel yield (92%) was obtained at 100 ºC, under autogenous pressure, using 5 wt. % of SnSO4 in excess of ethanol after 3 h of reaction. The catalyst was reused ten times without significant decrease in biodiesel yield.

Developing mesoporosity in HZSM-5 zeolites is an alternative for improving their catalytic performance on chemical reactions. In this work, alkaline and thermal treatments were used to produce mesoporosity. These treatments increased mesoporous area and volume. They also influenced the acid properties of the samples. Concerning catalytic performance, treatments modified reaction product distribution. Whereas alkaline treatment favored formation of olefins and increased propene ratio in the beginning of the reaction, thermal treatment resulted in formation of only ethylene due to the low acidity of the sample.

Automotive catalyst, using in Brazil since 1992, is a essential technology for vehicular emissions control. Noble metals are the active phase of these catalysts, and cerium zirconium mixed oxides (CZ), responsibles for the oxygen storage capacity (OSC), one of the most important aspect for the operational performance of the catalyst. In this context, the oxireduction properties analysis of CZ and Pd/CZ (palladium supported in CZ) system are the objective of this study, as well as, the impact of the thermal aging in the OSC. Aging consisted of treatments at 900 or 1200 °C, for 12 or 36 h, in oxidizing condition.