De acordo com a literatura, a reação de Diels-Alder de furano sem uso de catalisador pode durar várias semanas e apresenta baixo rendimento devido à baixa reatividade do dieno. O uso de catalisadores ácidos de Lewis ou de altas pressões são descritos como métodos eficazes para melhorar o rendimento da reação. Este trabalho descreve nosso estudo recente sobre a utilização de pentacloreto de nióbio, como catalisador em reações de Diels-Alder entre furano e alguns dienófilos reativos, entre os quais o acrilato de metila apresentou bons rendimentos, especialmente sob temperaturas mais baixas. Outros dienófilos apresentaram rendimentos mais baixos devido a problemas, tais como a formação de produtos secundários e de elevado caráter de reversibilidade da reação.

According to the relevant literature, the Diels-Alder reaction of furan without a catalyst can last several weeks and shows a low yield due to the diene's low reactivity. The use of Lewis acid catalysts or high pressures is described as an effective method for improving the reaction yields. This paper describes our recent study on the use of niobium pentachloride as the catalyst in Diels-Alder reactions between furan and several reactive dienophiles, among which methyl acrylate showed good yields, especially at lower temperatures. Other dienophiles have shown lower yields because of problems such as byproduct formation and the high reversibility of the reaction.

The quantity of salts in the crude oils depends on the origin and of the wells production and these salts cause several problems during the transport and the process of refine as corrosions, incrustations and deactivation of the employed catalysts in the refineries. In this study were implemented changes for improvements in the execution of ASTM D 6470 method and has also developed a new methodology of extraction system of salts using process of mechanical agitation without heating. The results of the optimization produce larger efficiency and safety to the process compared to the traditional ASTM method.