Study of Chemical Intermediates by Means of ATR-IR Spectroscopy and Hybrid Hard- and Soft-Modelling Multivariate Curve Resolution-Alternating Least Squares

Abstract

3,5-Diamino-1,2,4-triazole (DAT) became a significant energetic materials intermediate, and the study of its reaction mechanism has fundamental significance in chemistry. The aim of this study is to investigate the ability of online attenuated total reflection infrared (ATR-IR) spectroscopy combined with the novel approach of hybrid hard- and soft-modelling multivariate curve resolution-alternating least squares (HS-MCR) analysis to monitor and detect changes in structural properties of compound during 3,5-diamino-1,2,4-triazole (DAT) synthesis processes. The subspace comparison method (SCM) was used to obtain the principal components number, and then the pure IR spectra of each substance were obtained by independent component analysis (ICA) and HS-MCR. The extent of rotation ambiguity was estimated from the band boundaries of feasible solutions calculated using the MCR-BANDS procedure. There were five principal components including two intermediates in the process in the results. The reaction rate constants of DAT formation reaction were also obtained by HS-MCR. HS-MCR was used to analyze spectroscopy data in chemical synthesis process, which not only increase the information domain but also reduce the ambiguities of the obtained results. This study provides the theoretical basis for the optimization of synthesis process and technology of energetic materials and provides a strong technical support of research and development of energy material with extraordinary damage effects.

Extraction of Pure Species Spectra from Labeled Mixture Spectral Data

“…In general, the metabolites or their spectral signatures are not known a priori and have to be extracted by deconvolution of NMR spectra and using the spectra of those metabolities known to be present in normal samples. In online reaction monitoring using spectrophotometers, we may have to deal with short-lived (unstable) intermediates whose spectra cannot be obtained through direct measurement. For monitoring such reactions, the spectra of unstable intermediates can be obtained only through deconvolution of reaction mixture spectra …”

“…In online reaction monitoring using spectrophotometers, we may have to deal with short-lived (unstable) intermediates whose spectra cannot be obtained through direct measurement. For monitoring such reactions, the spectra of unstable intermediates can be obtained only through deconvolution of reaction mixture spectra …”

“…For monitoring such reactions, the spectra of unstable intermediates can be obtained only through deconvolution of reaction mixture spectra. 19 In addition, concentrations of some or all of the species in a mixture may be available through other analytical techniques. Such additional information in SMCR methods can be used to enhance not only the accuracy of pure species spectra extraction but also to guarantee unique solutions.…”