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Abstract: The main objective of this work is the functionalization of bentonite from the Amazon (region) by the grafting of propyl sulfonic acid groups to catalyze the esterification reaction of acetic acid and 1-propanol. Functionalization was accomplished by anchoring, oxidation and acid activation of (3-mercaptopropyl)trimethoxysilane, (MTPS). The procedure gave acid properties to the raw bentonite. This material, acting as a catalyst, increased the reaction speed and improved the yield by about 12% compared to the uncatalyzed reaction. The functionalized bentonite was characterized by XRD, TG/DTA, FTIR, N2 adsorption/desorption at 77K and XRF, and the surface acidity was determined by titration. [Copyright &y& Elsevier]

Abstract: The Brazilian production of bentonite is approximately 300,000t/year, with more than 88% of this production concentrated in small deposits located in the Paraíba state (northeast Brazil), which consequently are becoming exhausted. The objective of this paper is to present a new occurrence of bentonite from the eastern Amazon in northern Brazil, here referred to as Balsas bentonite. A selected sample of the material was characterized by XRD, TG/DTA, ICP-OES, FTIR, SEM-EDS, N2 adsorption/desorption at 77K and CEC. The main constituent of the bulk sample is montmorillonite. Kaolinite is completely absent, in contrast to some bentonites found in the famous Paraíba state. The results obtained from the mineralogical and chemical characterization confirm that this material, in comparison to some reference bentonites from the Clay Mineral Society Source Clays, has promise as an engineering material, indicating its possible use in various research and industrial applications. [Copyright &y& Elsevier]