An Experimental Raman and Theoretical DFT Study on the Self-Association of Acrylonitrile

Abstract

The liquid structure of acrylonitrile (propenenitrile) has been investigated using Raman spectroscopy and density functional theory (DFT) ab initio calculations with the 6-311++G** basis set. Two different and complementary experimental approaches were undertaken: FT-Raman spectra of 13 acrylonitrile solutions in carbon tetrachloride (concentration range=0.25-12.0 mol.L-1) were studied in detail including principal component analysis (PCA) of the CN stretching band. Furthermore, dispersive Raman spectra of neat acrylonitrile were obtained at eight different temperatures from 238 up to 343 K. The complex and asymmetric acrylonitrile Raman CN stretching band can be decomposed into two components attributed to monomeric and self-associated forms. Ab initio results fully support this assignment and suggest that the self-associated complex is a nonplanar trimer held together by dipole-dipole interactions. At ambient temperature, the composition of acrylonitrile can be expressed as a mixture of 25% monomers and 75% trimers. Close to the boiling point, trimers still represent 65% of the liquid composition. The corresponding enthalpy of association was estimated to be -22+/-2 kJ.mol-1.

Tuning nanophase separation behavior in segmented polyhydroxyurethane via judicious choice of soft segment

“…We hypothesize that this behavior arises from acrylonitrile units that are self-associating in the soft domain instead of participating in hydrogen bonding with hydroxyl groups. Self-association of acrylonitrile units due to a strong dipole-dipole interaction is well studied in the literature [92][93][94]. This self-association is also supported by the location of nitrile peaks of PBN-based PHUs from FTIR measurement (see Figure S8).…”

Quantification of the ion transport mechanism in protective polymer coatings on lithium metal anodes

“…The chemical cross-linking and the strong dipole-dipole interaction 28 between the nitrile groups make dissociation of the PAN segments more difficult and reduce the swelling ratio. (3) In contrast, the swelling of non-polar PBD segments in DME is more facilitated thanks to the lower degree of self-association between the PBD segments and thus results in higher swelling ratios.…”

Autodetachment Dynamics of Acrylonitrile Anion Revealed by Two-Dimensional Electron Impact Spectra

“…The assignment of the individual vibrations is indicated by vertical bars and labels in the lower part of Figure 1. The bars are drawn at energy-losses equal to the vibra-tional frequencies of neutral acrylonitrile [32]. The π * orbital where the incoming electron is temporarily captured is antibonding with respect to the C≡N and C=C bonds, making them longer and reducing the vibrational frequencies (Table I), thus providing a force for excitation of ν 4 and ν 5 , explaining their prominence in Figure 1.…”