An improved method has been used to synthesize perfluoroazo-2-propane. Pyrolysis over the temperature range 450-514 K in a static system has been shown to be a homogeneous, first-order process. No pressure dependence was observed in the presence of excess inert gas (SF6). The only products were nitrogen and perfluoro-2,3-dimethylbutane. The rate constant (k) for the decomposition process is given by: log(k/s(-1)) = 16.7 +/- 0.2 - (9856 +/- 109)/T These results lead to a straightforward mechanism for the decomposition process (1) i-C3F7N2 i-C3F7 --> i-C3F7N2 + i-C3F7 (2) i-C3F7N2 --> i-C3F7 + N-2 (3) 2i-C3F7 --> (i-C3F7)(2) The results are compared with those for other azo compounds. (C) 1994 John Wiley & Sons, Inc.

ChemInformVolume 20, Issue 33 Preparative Organic Chemistry ChemInform Abstract: Molecular Beam Sampled Laser Pyrolysis of Dimethylnitramine P. H. STEWART, P. H. STEWART Dep. Chem. Kinet., Chem. Phys. Lab., SRI Int., Menlo Park, CA 94025, USASearch for more papers by this authorJ. B. JEFFRIES, J. B. JEFFRIES Dep. Chem. Kinet., Chem. Phys. Lab., SRI Int., Menlo Park, CA 94025, USASearch for more papers by this authorJ.-M. ZELLWEGER, J.-M. ZELLWEGER Dep. Chem. Kinet., Chem. Phys. Lab., SRI Int., Menlo Park, CA 94025, USASearch for more papers by this authorD. F. MCMILLEN, D. F. MCMILLEN Dep. Chem. Kinet., Chem. Phys. Lab., SRI Int., Menlo Park, CA 94025, USASearch for more papers by this authorD. M. GOLDEN, D. M. GOLDEN Dep. Chem. Kinet., Chem. Phys. Lab., SRI Int., Menlo Park, CA 94025, USASearch for more papers by this author P. H. STEWART, P. H. STEWART Dep. Chem. Kinet., Chem. Phys. Lab., SRI Int., Menlo Park, CA 94025, USASearch for more papers by this authorJ. B. JEFFRIES, J. B. JEFFRIES Dep. Chem. Kinet., Chem. Phys. Lab., SRI Int., Menlo Park, CA 94025, USASearch for more papers by this authorJ.-M. ZELLWEGER, J.-M. ZELLWEGER Dep. Chem. Kinet., Chem. Phys. Lab., SRI Int., Menlo Park, CA 94025, USASearch for more papers by this authorD. F. MCMILLEN, D. F. MCMILLEN Dep. Chem. Kinet., Chem. Phys. Lab., SRI Int., Menlo Park, CA 94025, USASearch for more papers by this authorD. M. GOLDEN, D. M. GOLDEN Dep. Chem. Kinet., Chem. Phys. Lab., SRI Int., Menlo Park, CA 94025, USASearch for more papers by this author First published: August 15, 1989 https://doi.org/10.1002/chin.198933088Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume20, Issue33August 15, 1989 RelatedInformation

Elementary bimolecular processes that involve the formation of a chemically activated intermediate are common. In a previous paper we described the information required to ensure that a kinetic model will extrapolate the rate constants involved over wide ranges of temperature and pressure. This approach is illustrated here for the system centered around the ethane intermediate. It is necessary and sufficient to specify the temperature and pressure dependence of three rate constants k(T,P) and the temperature dependence of two equilibrium constants K(T), viz.,

Extrapolation of rate constant data to temperatures and pressures far from the original experimental conditions is common in combustion modeling. However, great care must be taken when performing such an extrapolation in order to prevent gross errors. Modelers should be able to consult tables of parameters for combustion-relevant reactions that would enable the calculation of rate constants as a function of temperature and pressure over the entire range of interest. A complete tabulation would include both uni-and bimolecular reactions, including those bimolecular reactions proceeding via a bound intermediate. In this paper we illustrate the usefulness of such an approach for the H-atom abstraction reactions from ethane and neopentane by O-atoms, OH-radicals and CH3-radicals and for the more complex reactions CH4=CH3+H, OH+CO=CH2+H and CH3+CH3=C2H5+H.

AbstractSingle‐channel hindered Gorin model RRKM calculations were performed on reaction (1). equation image Good agreement between theory and experiment was obtained for the temperature and pressure dependence of reaction (1). Isotopic data for the reverse association reaction, (−1), reported previously, are consistent with the model. Rate constants were cast in the form of an analytical expression and appropriate parameters were tabulated.

AbstractElementary bimolecular processes that involve formation of a chemically activated intermediate species are common. We address the general problem of modeling these processes and describe the necessary and sufficient information that must be specified to assure that a kinetics model will extrapolate the rate constants for those reactions over wide ranges of temperature and pressure. The approach is illustrated for the system centered around the HOCO intermediate. Here, specification of the temperature and pressure dependence of three rate constants, k(T,P) and the temperature dependence of two equilibrium constants, K(T), is necessary and sufficient, viz: equation image Rate constants are cast in the form of an analytical expression, suggested by Troe, and appropriate parameters are tabulated.

Abstract : As a prototype for more complex nitramines, the gas-phase decomposition of dimethylnitramine has been studied experimentally in two different laser-pyrolysis systems and theoretically using ab initio quantum mechanical calculations. Our studies, unlike those reported in the literature, indicate that a nitro-nitrite rearrangement pathway is competitive with the expected (and previously invoked) N-NO2 bond scission. This rearrangement pathway has been obscure because it can lead to some of the same products as are yielded by the bond scission route. The principal evidence for nitro-nitrite rearrangement is (1) Arrhenius parameters for decomposition that are two orders of magnitude too low to be consistent with simple N-NO2 bond scission as the sole rate-determining step; (2) molecular-beam, mass-spectrometrically-sampled laser pyrolysis studies that show direct detection of NO and the nitroxyl radical (CH3)2NNO on a time scale too short to allow for the production of these substances in secondary bimolecular reactions; and (3) ab initio calculations that find a rearrangement pathway at slightly lower energy than that of simple bond scission.