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Acta Geodynamica et Geomaterialia

 
Title: CHARACTERIZATION OF SURFACE ACIDITY AND CATALYTIC ABILITY OF NATURAL CLAY MINERALS BY MEANS OF TEST CATALYTIC REACTION
 
Authors: Novikova Lyudmila, Belchinskaya Larissa, Roessner Frank and Alsawalha Murad
 
DOI: 10.13168/AGG.2013.0048
 
Journal: Acta Geodynamica et Geomaterialia, Vol. 10, No. 4 (172), Prague 2013
 
Full Text: PDF file (0.4 MB)
 
Keywords: test catalytic reaction; methylbutynol conversion; surface acidity; clay minerals
 
Abstract: Catalytic test reaction of methylbutynol (MBOH) conversion was applied to investigation of natural clays and non-clay minerals from Jordanian (bentonite, kaolinite, diatomite, zeolite) and Russian (palygorskite, kaolinite, hydromica) deposits as well as H-ZSM-5. Palygorskite and kaolinite containing samples have shown the highest catalytic activity. Conversion over Jordanian clay minerals decreased in the order: zeolite > bentonite > red kaolinite > white kaolinite > diatomite that agreed to change of acidity, surface area of samples. Sufficient deactivation was observed for H-ZSM-5, kaolinite and hydromica due to adsorption of secondary product in micropores of raw minerals. Products of both acidic and basic pathways of test reaction were formed indicating the presence of acid and basic sites on clays surface, apart from acidic catalyst H-ZSM-5. The yield ratio of acidic to basic products was above the unity for zeolite, bentonite, red kaolinite, and palygorskite; equal to unity for diatomite and hydromica, and less then unity for white kaolinite. It was observed for kaolinite containing sample that high activation temperature increased conversion of MBOH owing to formation of additional basic sites as a result of mineral dehydroxylation. Rise of montmorillonite content from 30 to 80 % provided 91-97 % of MBOH conversion.