New phospho-silicate and niobo-phospho-silicate MCF materials modified with MPTMS - Structure, surface and catalytic properties

Phosphorus (P) was introduced into MCF and NbMCF materials during one-pot synthesis and by post-synthesis modification. The materials obtained were used as supports for grafting of (3-mercatopropyl)trimethoxysilane (MP) oxidized by H2O2 to transformation of SH towards sulphonic groups. The focus in this work is on the deep insight into the textural parameters of the materials, estimation of the efficiency of P and Nb incorporation into MCFs, surface acidic properties and activity and selectivity in acetic acid esterification with glycerol. Phosphorus is much easier included into the structure of MCF when the source of niobium is present in the synthesis gel. However, much higher amount of phosphorus is loaded by the impregnation procedure. Niobium has an influence on thiol species oxidation (in MP) leading to obtain a higher amount of acidic centers. The introduction of P species creates the additional Bronsted acid sites (BAS). The best performance in catalytic esterification of acetic acid with glycerol shows the material prepared in one-pot synthesis with the use of all components (Nb, P and MP). (c) 2013 Elsevier Inc. All rights reserved.