Please cite this article in press as: K. Stawicka, et al., Mesostructured cellular foams modified by niobium or tantalum and functionalized with (3-mercaptopropyl)trimethoxysilane – Raman inspired reduction of synthesis time, Catal. Today (2014), http://dx.doi.org/10.1016/j.cattod.2014.11.035 ARTICLE IN PRESS G Model CATTOD-9385; No. of Pages 8 Catalysis Today xxx (2014) xxx–xxx Contents lists available at ScienceDirect Catalysis Today j our na l ho me page: www.elsevier.com/locate/cattod Mesostructured cellular foams modified by niobium or tantalum and functionalized with (3-mercaptopropyl)trimethoxysilane – Raman inspired reduction of synthesis time Katarzyna Stawicka a,b,∗ , Vanesa Calvino-Casilda b,c , Maciej Trejda a , Miguel A. Ba˜ nares b , Maria Ziolek a a Adam Mickiewicz University in Pozna´ n, Faculty of Chemistry, Umultowska 89b, PL-61-614 Pozna´ n, Poland b Catalytic Spectroscopy Laboratory, Instituto de Catálisis y Petroleoquímica, CSIC, Marie Curie, 2, E-28049 Madrid, Spain c Departamento de Química Inorgánica, UNED, Senda del Rey, 9, E-28040 Madrid, Spain a r t i c l e i n f o Article history: Received 7 October 2014 Received in revised form 27 November 2014 Accepted 28 November 2014 Available online xxx Keywords: MCF MPTMS Niobium Tantalum In situ Raman a b s t r a c t The synthesis of mesostructured cellular foams (MCF) modified by niobium or tantalum source and functionalized with MPTMS (3-mercaptopropyl)trimethoxysilane was monitored in situ by Raman spec- troscopy. The results from Raman monitoring prompted us to check for a possibility of shorter time synthesis of mesostructured cellular foams. A series of MCFs materials prepared using different times of gel mixing (5 h and standard 20 h) were synthesized. The samples obtained were characterized by N 2 adsorption/desorption, XRD, TEM, XRF, elemental analysis, UV–Vis, FTIR and amperometric titration. The effects of niobium and tantalum on the rate and efficiency of thiol oxidation as well as on the time of silica formation were explored. The most important outcome of the study is the evidence of the formation of MCFs materials having strong Brønsted acidic centers in a shorter preparation time. SO 3 H groups form faster than in MP-MCF material in the presence of niobium or tantalum in the synthesis gel. The extension of synthesis time for silica and tantalosilicate samples leads to more efficient oxidation of thiol species. This feature does not depend on the synthesis time of niobiosilicate materials. © 2014 Elsevier B.V. All rights reserved. 1. Introduction Much emphasis is currently put on the synthesis of het- erogeneous materials with strong acidic properties, which can replace homogeneous systems because of environmental and eco- nomical problems. The processes carried out in the presence of homogeneous catalysts can generate difficulties with the catalysts separation from reaction mixture, resulting in waste generation. Additionally, part of the products can also be lost leading to eco- nomic drawbacks. Homogeneous catalyst can hardly be reused, which is a drawback for industrial application [1–3]. The above- mentioned issues usually do not apply for heterogeneous catalysts, which can be separated, regenerated and used again if stable enough [3]. ∗ Corresponding author at: Adam Mickiewicz University in Pozna ´ n, Faculty of Chemistry, Umultowska 89b, PL-61-614 Pozna ´ n, Poland. Tel.: +48 61 8291305; fax: +48 61 8658008. E-mail address: kasiakob@o2.pl (K. Stawicka). There are different types of solid materials with strong acidic centers on their surface, including zeolites, resins or modified sil- icas [4–9]. Zeolites have small size pores and cannot be used as catalysts for the reactions carried out in the presence of large molecules like acetic acid and glycerol, where bulky esters are formed as products [4,5]. Resins, like Amberlyst 15 and Nafion SAC 13, are very active in the esterification processes alas, they show a few drawbacks, including low thermal stability, thus the use of these materials at higher temperatures is limited. Moreover, resins have got low surface area and small ability for regenera- tion, which makes them less attractive for industrial applications [10,11]. The above-mentioned problems can be overcome by the application of mesoporous silica like SBA-1 [12], SBA-15 [13–16], MCF [8–10,17,18] or MCM-41 [12,19] modified with an organosi- lane. There are many types of organosilanes that are used for silica modification to obtain materials with strong acidic properties. The most common are MPTMS [6,8,9,13,18], CSPTMS (2-(4- chlorosulfonylphenyl)ethyltrimethoxysilane) [6,13,20] or CSPETCS (2-(4-chlorosulfonylfenyl)ethyltrichlorosilane) [10], which allow incorporation of thiol groups (from MPTMS) or sulphonic groups (from CSPTMS and CSPETCS) on silica surface. Sulphonic groups http://dx.doi.org/10.1016/j.cattod.2014.11.035 0920-5861/© 2014 Elsevier B.V. All rights reserved.