Isomerization-cracking of n-octane on catalysts based on heteropolyacid H3Pw12O40 and heteropolyacid supported on zirconia and promoted with Pt and Cs

Abstract

Recebido em 10/9/12; aceito em 1/3/13; publicado na web em 4/6/13Isomerization-cracking of n-octane was studied using H 3 PW 12 O 40 (HPA) and HPA supported on zirconia and promoted with Pt and Cs. The addition of Pt and Cs to the supported HPA did not modify the Keggin structure. The Pt addition to the supported HPA did not substantially modify the total acidity; however, the Brönsted acidity increased significantly. Cs increased the total acidity and Brönsted acidity. A linear relation was observed between the n-C 8 total conversion and Brönsted acidity. The most adequate catalysts for performing isomerization and cracking to yield high research octane number (RON) are those with higher values of Brönsted acidity.

Hydrocracking of Fischer‐Tropsch Wax with Tungstovanadophosphoric Salts as Catalysts

“…Various articles have been published on HPA catalyzing the cracking and isomerization of hydrocarbons, but they deal almost exclusively with hydrocarbons having C‐numbers equal to or below 10 . Attention has also been paid to acidic cesium salts of phosphotungstic acid like Cs 2.5 H 0.5 PW 12 O 40 .…”

“…), and catalytic activity can be linked very well to surface acidity for several reactions . Furthermore, cesium phosphotungstates can act as carriers for catalytically active transition metals such as platinum, palladium, and nickel , , , .…”

Effect of phosphomolybdic acid on the catalytic behavior of bifunctional Pt‐Cr/nanocrystalline Y zeolite in hydroisomerization of n‐octane

“…In this regard, the heteropoly acids, which have been used successfully as superacid catalysts in different chemical reactions, would be candidates as a Brønsted acid site for the isomerization reaction. The delocalization of the negative charge on the large anion of a heteropoly acid enables its protons to easily participate in the isomerization reaction . As a consequence, we observed that, under the same test conditions, the activity of Pt/HPMo‐Y catalyst was higher than the Pt/Y catalyst.…”

“…The adequacy and significance of the second‐order quadratic model was evaluated using an analysis of variance (ANOVA), and the results of the statistical analysis are represented in Table . The fitted model was significant because of the very low probability value ( P model < .0001) and high F‐value of the model ( F model = 30.32) at a confidence level of 95% . Therefore, the prediction of the iso‐alkane yield based on the regression model was suitable.…”