Infrared multiphoton dissociation of 2-chloro-1,1,1,2-tetrafluoroethane in a molecular beam

Abstract

Mechanism and dynamics of the infrared multiphoton dissociation of 2-chloro-1, 1,1,2-tetrafluoroethane have been studied using a photofragmentation translational spectroscopy. The molecule dissociates competitively through three-centered elimination of HCl and C–Cl bond rupture. The HCl elimination reaction accounts for 74% of the total primary dissociation yields. The center-of-mass translational energy distribution for the HCl elimination indicates that an exit barrier of several kcal/mol exists along the reaction coordinate on the potential energy surface. The infrared multiphoton dissociation of CF3CF produced by the HCl elimination from CF3CHClF also occurs as a secondary process through its dissociation into two CF2 molecules. The average excitation energy of dissociating CF3CHClF has been determined to be about 20 kcal/mol above the C–Cl dissociation threshold of the molecule by comparing the observed center-of-mass translational energy distribution for the C–Cl bond rupture reaction with that calculated by Rice–Ramsperger–Kassel–Marcus (RRKM) theory.

Ab initio, DFT and transition state theory calculations on 1,2-HF, HCI and CIF elimination reactions from CH2F–CH2Cl

“…6 However, as clearly explained by Gilbert and Smith, 12 strict applications of eqn. (2) unambiguously show it to be 1. The factor of 2 arises for CFE, DFE and DCE because of the presence of 2 optical isomers at the TS for these molecules i.e.…”

“…The HX elimination reactions from haloethanes have continued to attract both experimental [1][2][3][4][5][6] and theoretical efforts. [6][7][8][9][10] One of the main reasons for this interest is the fact that these reactions offer an excellent example for a truly unimolecular reaction involving complicated motions along at least 4 bonds.…”

Unimolecular Reaction Dynamics of CH3COCl and FCH2COCl: An Infrared Chemiluminescence and ab Initio Study

“…We followed the model developed by Rakestraw and Holmes for CF 3 CH 2 Cl . The log A for this TS was 14.62, and it is comparable to that of CF 3 CH 2 Cl (14.6) 35 and CF 3 CHFCl (14.7) . For CH 3 COCl, transition states for C−C and C−Cl dissociation were chosen in a similar fashion.…”

Dynamics of hydrogen chloride elimination from halogenated ethane induced by infrared multiphoton absorption

“…In this work, the dissociation dynamics of the three-and four-center HC1 eliminations is elucidated by measuring the rotational and vibrational state distributions of HC1 in addition to the relative translational energy distributions. 7 We have chosen the IRMPD of 2-chlolo-1,1,l,2-tetrafluoroethane (CTEFE) and 1-chloro-1,1-difluoroethane (CDFE) for the model systems of the three-and four-center HC1 eliminations, respectively. The translational energy distribution ofHCl from CDFE has been reported by sudbø et al'2…”

“…We have studied dissociation mechanisms and dynamics of several halogenated hydrocarbons induced by infrared multiphoton absorption using a . [7][8][9][10][11] .…”