Structural and Catalytic Properties of the Binary Systems Alumina – Amorphous Aluminosilicate

Abstract

The amorphous aluminosilicate – alumina systems were examined using various physicochemical methods, including the analysis of ²⁷Al NMR spectra of solid samples, estimation of the catalyst acidity by temperature-programmed desorption of ammonia, investigation of the sample structure by X-ray diffraction analysis, and thermogravimetric analysis of the samples. A study on the catalytic properties of the samples upon cracking on the model feedstock n-dodecane in a mixture with 2-methylthiophene revealed that conversion of the feedstock increases in the series: 100 % Al₂O₃ (AH) > 70 % Al-Si + 30 % Al₂O₃ (AH) > 30 % Al-Si + 70 % Al₂O₃ (AH) > 100 % Al-Si (AH – aluminum hydroxide obtained by sulfate method; Al-Si – amorphous aluminosilicate). An increase in the calcination temperature of the samples from 500 to 700 °C decreases the conversion of the feedstock. The growing contribution of hydrogen transfer reactions leads to an increase in the formation selectivity of hydrogen sulfide and a decrease in the content of sulfur compounds in the liquid products.