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Pentane Transformation over Silicaalumina/BCl3 Solid Superacid

Marczewski M., Dębowiak M., Marczewska H.

Polish Journal of Chemistry

2003

Vol. 77 / nr 5

737-747

Pentane transformation over SiO2(87%) - Al2O3/BCl3 superacid was studied. It was found that Brönsted superacid centres formed in the reaction between the carrier and BCl3 vapours are active in n-pentane low temperature transformation. Pentane is converted over them into carbenium ion (through intermediate carbonium ion), which either undergoes isomerization to form 2-methylbutane or reacts with a second molecule of the reactant forming 2-methylpropane and a longer surface carbenium ion. The latter acts as a secondary active centre for 2-methylpropane formation and also undergoes further transformation leading finally to coke.

The Role of Lewis Acid - Lattice Oxygen reaction in Solid Superacids Formation

Marczewski M., Marczewska H., Witosławski K.

Polish Journal of Chemistry

1999

Vol. 73, nr 10

1733-1738

Two reactions are responsible for superacid properties of SbF5(BF3) - carrier catalysts. The reaction between surface OH groups and SbF5(BF3) results in Bronsted acids centres formation. lewis acid adsorption on O2- diminishes the basicity of the surface enhancing the acid strength of Bronsted sites.

Bronstedd and Lewis solid superacids of carrier/metal halide type

Marczewski M., Marczewska H., Juszczyk W.

Polish Journal of Chemistry

1999

vol. 73 nr 3

509-518

Superacid properties of alumina, silica-alumina and silica exposed to TiCl4 and HfCl4 vapour have been studied and compared with previously obtained results for catalysts containing BF3, SbF3, AlCl3 and ZrCl4. It was found that the reaction of the vapour of metal halides of Lewis nature (MeXn) with oxides like alumina, silica-aluminas and silica results in the formation of the Bronsted superacid centers if acid strength of hypothetical acid MeXn×XH is higher than that of sulphuric one. The Lewis superacid centers are formed in the reaction of carrier containing alumina phase with metal halide of strong electron acceptor ability.