Microwave-assisted synthesis of sulfonic acid-functionalized microporous materials for the catalytic etherification of glycerol with isobutene

• Published in: Green chemistry : an international journal and green chemistry resource : GC Vol. 15; no. 8; pp. 223 - 2239
• Main Authors: Gonzlez, Mara Dolores, Salagre, Pilar, Taboada, Elena, Llorca, Jordi, Cesteros, Yolanda
• Format: Journal Article Publication
• Language: English
• Published: Cambridge Royal Society of Chemistry 01.01.2013
• Subjects: Accessibility; Aliphatic compounds; Catalitzadors; Catalysis; Catalysts; Catalysts: preparations and properties; Chemistry; Energies; Evolution; Exact sciences and technology; General and physical chemistry; Glycerols; Microwaves; Organic chemistry; Porosity; Preparations and properties; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Zeolites; Àrees temàtiques de la UPC; Isobutene; X ray; Etherification; Porous material; Molecular sieve; Surface structure; Characterization; Functionalization; Photoelectron spectrometry; Clay; Scanning electron microscopy; Catalytic reaction; Montmorillonite; Glycerol; Zeolite; Microwave heating; X ray diffraction; Sulfonic acid; Operating conditions; Heterogeneous catalysis; Microporosity; Morphology; Preparation; Catalyst; Physicochemical properties
• ISSN: 1463-9262; 1463-9270
• DOI: 10.1039/c3gc40683k

Commercial Beta, ZSM-5 and mordenite zeolites and commercial montmorillonite K-10 were successfully sulfonated by a one-step simple method using microwaves. Different amounts of the sulfonating agent were required to maximize the incorporation of sulfonic groups for each structure. This has been related to the different dealumination degree suffered by the starting samples during sulfonation together with the different accessibility of the silanols to the sulfonic groups depending on the arrangement and size of their pores. All optimised sulfonated catalysts showed total conversion and very high selectivity (7991%) to h-GTBE (glycerol di- and tri-ethers), in spite of their microporosity, due to the incorporation of the sulfonic groups that led to a higher number and strength of Brnsted acid sites. Pore size and arrangement together with the external surface area of the catalysts affected the accessibility of the acid sites to the reactants, explaining the evolution of the catalytic results with time for each structure. Optimized microwave-assisted sulfonated beta, ZSM-5, mordenite and montmorillonite K-10 catalysts showed total conversion and very high selectivity (7991%) to h-GTBE (glycerol di- and tri-ethers), which can be used as a fuel additive.