NIR spectroscopy for reaction monitoring and reaction mixture identification of cycloaliphatic epoxides.

The industrially relevant cycloaliphatic epoxides do not have a directly distinguishable band in the NIR spectrum and their polymerisation conversion has so far typically been estimated via the simultaneous polymerisation of vinyl ethers. Here, an analytical procedure is presented for the quantitative inline analysis of 4-epoxycyclohexyl methyl-3,4-epoxycyclohexane carboxylate without the need to mix cycloaliphatic epoxides with vinyl ethers. By employing multivariate data analysis on the reaction spectra, the conversion could be analysed spectroscopically. This resulted in a mean uncertainty of 3.38% conversion in the range between 0 and 40% conversion. In addition, a deviation from the initial monomer concentration of 5 w% over a temperature range of 100 °C can be detected and identified via principal component analysis. [ABSTRACT FROM AUTHOR]