Silanes, comparison with carbon compounds

Abstract—The nature of the product of the reaction between an aminated silane and carbon dioxide was re-examined with the aid of simple model compounds, several amines, and several aminosilanes. Since the reaction products previously proposed include the amine bicarbonate and a carbamate derived from the amine, ammonium bicarbonate and ammonium carbamate were studied as models for the anions. Carbon dioxide adducts of neat model amines were prepared and studied. Results from a variety of techniques are summarized. Among the most useful was Fourier transform infrared (FTIR) spectroscopy of fluorolube mulls. FTIR spectra were distinctive and assignments characteristic of the two species were extracted from the spectral data. Comparisons of these assignments with the products of the reaction between carbon dioxide and various amines were made. The results indicate that alkylammonium carbamates are the principal product. Nuclear magnetic resonance (NMR) spectra in D20 indicated much dissociation and were not helpful in defining the products. 

For a comparison the interaction of the initiators 2,2-dimethoxy-2-phenylacetophenone (DMPA), (2-hydroxy-2-propyl)phenone la (bothnon-coreactive) and the epoxide If with silica was also investigated.Silica was treated with 0.5 weight equivalent of these compounds in the same manner as previously described for the silanes Id,e. Ihe resulting materials were analyzed by e.a. (Table III). The results of e.a. are primarily given as percent carbon because the structure of the organic species on silica is not absolutely clear (a trihydroxy compound is assumed as derivative of If). 

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