(530g) Novel Method for Synthesizing Non-Leaching Functionalized Mesoporous-Silica for Acid Catalyzed-Alkylation Reaction

Santiago J. Umbarila^§, Tuong V. Bui^§, Tawan Sooknoi, Daniel E. Resasco*

^§Both authors contributed equally to this work

School of Chemical, Biological and Materials Engineering, University of Oklahoma, 100 East Boyd Street, Norman, Oklahoma, 73019, United States

*Corresponding Author: resasco@ou.edu

ABSTRACT

The ordered mesoporous silica materials such as MCM-41 and SBA-15 have attracted special attention because of its chemical and thermal stability¹. Several studies have been reported modification method of the silica surface through conventional grafting (CG) and co-condensation (CC) functionalization^1–6. The CG modifies the surface via sylilation of the free silanols with organosilanes. In turn, the CC method uses the TEOS as the a building block for generating the silica structure in the one-pot mixture with organosilanes, which act as functional moieties. The resulting hybrid materials has the characteristic mesoporous hexagonal structure together with organic functional groups anchoring on the surface.

It has been reported that the Si-O bonds obtained from conventional functionalization process are thermally stable, but only under rather mild conditions, which in turn do not cause any loss of active moieties via the leaching or decomposition. There are only a few studies that report the leaching under more severe chemical conditions in either non-polar ^5–7 or polar solvents ⁸. In this study, the leaching process will be investigated at the molecular level by utilizing a combination of techniques including Fourier-Transform Infrared Spectroscopy (IR), Transmission Electron Microscopy (TEM), Solid-State Nuclear Magnetic Resonance (NMR) of ²⁹Si, ¹H and cross polarization ¹H-²⁹Si, X-ray Diffraction (XRD).

In addition, a new synthesis method that we identify as "dry-grafting" will be proposed. This method provides a novel and simple way to synthesize stable non-leaching materials useful as catalysts in acid-catalyzed reactions, even under severe conditions (e.g. in polar solvents, at high temperature, etc). The catalytic stability is examined for the alkylation reaction between cyclopentanol (CPOL), acting as the alkylation agent and m-cresol as a substrate. This model compound reaction has practical relevant to biomass conversion and upgrading of pyrolysis vapors into chemicals and drop-in transportation fuels.

Key words: Dry grafting, Leaching, Mesoporous silica, Alkylation and Biomass conversion

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