TEOS Oligomers and Transesters Identified by GC-MS in the sol-gel Process. Operational Mass Spectral Libraries

Abstract

The aim of this article is the presentation of new user mass spectral libraries created based on unambiguous assigning of the mass spectra of the tetraethoxysilane (TEOS) oligomers and transesters obtained in the sol-gel process. Gas-chromatography coupled with mass spectrometry (GC-MS) was used to unambiguous identification the TEOS oligomers and transesters obtained in the hydrolysis, condensation and transesterification, reactions of tetraethoxysilane in parental solvent (EtOH) and nonparental solvents (MeOH and n-PrOH). The author�s procedure for the interpretation of mass spectra of silicon alkoxides was applied for TEOS, TEOS dimer, methoxy-transesters, and TEOS cyclic tetramer. GC and MS arguments for unambiguous assigning of TEOS oligomers and transesters in the sol-gel process were presented. Experimental B/E and B/E(1-E)1/2 linked scans, accurate mass at high resolution and M+1, M+2 isotopic effects, applied in previous works, were used as MS arguments. The NBS mass spectral library run under the RSX-11-PLUS operating system was used to create new mass spectral libraries. In this article are presented three user mass spectral libraries codified: TRANSME0 for methoxy-transesters, PROPOXY1 for propoxy-transesters in the histogram plot and tabular format and ICECHIM6 (first 12 entries in histogram plot format) for TEOS oligomers in the parental solvent.