No abstract

The catalytic hydrogenation of acrylonitrile-butadiene copolymer (nitrile rubber, NBR) using Pd(OAc) 2 or RuCl 2 (PPh 3 ) 3 catalysts has been investigated in order to produce a totally saturated nitrile rubber. The hydrogenation of NBR is effective with both catalysts and achieved total conversion under the appropriate reaction conditions. In the case of palladium the effects of reaction parameters such as reaction temperature, pressure, time, catalyst concentration, and NBR concentration have been investigated. Even though both ruthenium-and palladium-based catalysts are effective in the production of HNBR, the former requires harsh reaction conditions and has the drawback of gel formation under high conversion, motivating the migration to RuCl 2 (PPh 3 ) 3 as an alternative catalyst. The degree of hydrogenation was determined by IR and NMR spectroscopy.

Here we investigate the production and characterization of mono-acylglycerols through the glycerolysis of biodiesel, a methyl ester mixture, obtained from linseed oil. The biodiesel employed was derived from linseed oil through transesterification according to transesterification double step process [1]. The efficiency of H 2 SO 4 , CaO, and NaOH as catalysts was evaluated for the production of monoacylglycerols. The glycerolysis reactions were performed by varying the molar ratio of the reagents (biodiesel:glycerol), the type and amount of catalyst, reaction time and temperature. Systematic evaluation of reaction yield is shown as a function of these parameters. Reaction products were characterized through IR spectroscopy, hydrogen NMR, and the GC techniques. The study of three different catalysts indicated that the most efficient was 5% NaOH in a 1:5 biodiesel-glycerol molar ratio with 10 h reaction time. The reaction reached a maximum of 85% biodiesel conversion with a monoacylglycerol yield of 72% at 1308C.

Acrylonitrile-butadiene rubber (NBR) latex was hydrogenated using diimide in the presence of selenium catalysts under an oxygen atmosphere. The process has been optimized and is extremely effective in the hydrogenation of NBR latex, with more than 3350 carbon-carbon double bonds reduced per atom of selenium in 5 h at 60 C. The amount of gel formed was controlled with gel inhibitors such as Irganox. This process constitutes a new route for obtaining totally hydrogenated acrylonitrile-butadiene polymer with low amounts of gel and very low amounts of selenium contaminants.

The synthesis of monoacylglycerol (MAG) through the glycerolysis of ethyl ester mixture (biodiesel) was investigated in this study from linseed oil, low-cost alternative feedstock, using an alkaline catalyst with green reagent.

The kinetics of hydrogenation of the acrylonitrile-polybutadiene (NBR) rubber by the action of hydrazine in the presence of selenium and oxygen was studied by varying reaction parameters such as latex and catalyst concentrations. The method of initial rates gives a reaction order of 0.91 and a rate constant of 3.2 Â 10 1 L mol À1 h À1 in relation to the NBR latex concentration, and an order of 0.86 and a rate constant of 3.3 Â 10 1 L mol À1 h À1 in relation to the catalyst concentration. Based on these values, a first-order mechanism with the formation of a diimide intermediate is suggested, which is formed through the oxidation of hydrazine in an oxygen atmosphere in the presence of selenium catalyst. This diimine species reacts rapidly, reducing the carbon-carbon double bonds of NBR resulting in the formation of HNBR rubber.

The soot oxidation activity of metallic iron nanoparticles was studied under real diesel engine conditions. Particulate matter (PM) was sampled at distinct temperatures, using fuels containing ferrocene. The results indicated an 80% reduction of accumulated PM using fuels doped with 50 ppm ferrocene at a temperature of 460• C. Temperature-programmed catalytic oxidation tests indicated that PM oxidation in ferrocene-doped fuels starts at an approximately 200• C lower temperature. The transmission electron microscopy (TEM) analysis of the PM revealed that soot agglomerates with and without the presence of Fe showed a similar morphology and that the average diameter of iron nanoparticles is 10 nm. The use of ferrocene-doped diesel fuels increases the speed of PM oxidation significantly, enabling the filter to self-regenerate at the average temperature of the exhaust gases. Moreover, 500 ppm of sulfur in fuels does not reduce the catalytic activity of iron nanoparticles in PM oxidation.