Mechanistic Investigation of Sol–Gel Reactions Using Alkoxysilane Precursor

Main Article Content

Adam Hassan Elhaj Yousif
Mohammed Sulieman Ali Eltoum

Abstract

The present study has been carried out to investigate the mechanisms of sol–gel reactions using TEOS as precursor in the presence of acid or base catalyst. The gels were prepared by hydrolysis of TEOS using hydrochloride acid or ammonium hydroxide catalyst. The obtained gels were also characterized by FTIR spectroscopy. The results of FTIR spectroscopy indicated the existence of silanol and siloxane bonds; due to the formation of hydrolyzed species as reactive intermediate compounds in initial stage converted by condensation reactions to gels as ultimate products. Accordingly, appropriate mechanisms have been proposed for sol – gel reaction using TEOS as precursor in the presence of acid or base catalyst. These mechanisms involve three-steps SN2 mechanisms for base catalyzed hydrolysis reaction of TEOS and SN1 mechanisms for acid catalyzed hydrolysis reaction of TEOS. Three mechanisms have been also proposed for condensation reaction as second stage in sol-gel process. These mechanisms include alcoxolation, oxolation and oltaion.

Keywords:
Sol–gel, TEOS, precursor, mechanism, FT-IR spectroscopy.

Article Details

How to Cite
Yousif, A. H. E., & Eltoum, M. S. A. (2020). Mechanistic Investigation of Sol–Gel Reactions Using Alkoxysilane Precursor. Chemical Science International Journal, 29(5), 25-31. https://doi.org/10.9734/CSJI/2020/v29i530178
Section
Short Research Article

References

Dorchech AS, Abbasi MH. Journal of Materials Processing Technology. 2008; 199:10-26 .

Yousif AHE, Alhussein OY, Elgorashi EAM, Ali MS, Eldogdug WI. International Journal of Innovative Science, Engineering and Technology. 2016;3(1):259-271.

Nadargia DY, Kalech RR, Rao AV. Journal of Alloys and Compounds. 2009;480:689-695.

Gurav JL, Jung IK, H. Yung – Ho Park, E.S. Kang and D.Y. Nadargi, Journal of Nanomaterials. 2010;3.

Khimich NN. Glass Physics and Chemistry. 2004;30 (5):430-442 .

Estella J, Echeverria JC, Laguaa M, Garrido JJ. Journal of Non–Crystalline Solid. 2007;353:286–294 .

VoronKov MG, Khimich EN, Khimich NN. Russian Journal of Applied Chemistry. 2008;81(4):732-735.

Biddle KD. PhD Thesis, University of Manchester. 1982;42-48.

Kessler VG, Spijksma Gl, Seisenbaeva GA, Hakansson S, Blank DHA, Bouwmeester HJM. JSol-Gel SciTechn. 2006;40:163-179.

Cheng X, Chen D, Liu Y. Chemphyschem. 2012;13(9):2392-404.

Al-Oweini R, El-Rassy H. Journal of Molecular Structure. 2009;919:140-145.

Amean KB, Rajasecker K, Rajasekharan T. J.Sol- Gel Sci. Technol. 2008;459-15.

Dabryanska HI, Melnyk IV, Zub YUL, Chuiko AA, Dabrowski A. Russian Journal of Physical Chemistry. 2006;80(6): 939-944.