The relative yields of CH3NO2, CH3ONO, and CH3ONO2 have been measured at five temperatures between 323 and 455 K above 300 torr of pressure. Kinetic modelling of the observed CH3NO2/(CH3ONO + CH3ONO2) and CH3ONO/CH3ONO2 ratios from this study and that of Phillips and Shaw (Ref. 5), with and without added NO, led to the rate constant for CH3 + NO2 → CH3NO2 (1), k1 = 6.0x1012 cc/mol-sec, and for CH3O + NO2 → CH3ONO2 (4), k4 = 7.5x1012 cc/mol-sec. The results of the modelling also indicate that the oxidation of CH3NO by NO2 accounts for a large fraction of CH3NO2 formed in the NO-added mixtures. The rate constant for this reaction is estimated to be k25 ≃ 1.3×109e(-10,000/RT) cc/mol-sec. Combination of k1 with the equilibrium constant for reaction (1) gives rise to the rate constant for the decomposition of CH3NO2, k−1 = 1.3x1016e(-60,050/RT) sec−1.

1-Nitroadamantane was produced by irradiating a solution of adamantane and NO2 in CCl4 with the visible lines (457.9–514.5 nm) of an argon-ion laser. At these wavelengths NO2 does not photodissociate to form O atoms, and thus the nitration reaction must be initiated by another species, probably vibronically excited NO2 (NO 2 *† ). The intensity of the laser enables the reaction to be carried out in a reasonable length of time, despite the strong quenching of NO 2 *† by CCl4.

The reaction of NO2 with isobutane, induced by 488 nm laser radiation, to form 2-nitro-2-methylpropane has been investigated and the results computer-modeled according to two possible reaction mechanisms. The first scheme involves the direct abstraction of H from isobutane by vibronically excited NO2 (NO2*?), and the second, abstraction by an intermediate NO3 radial produced by NO2*?+NO2. The modeling results strongly support the NO2*? scheme as the dominant reaction mechanism.

Dimethylnitramine (DMNA) was pyrolyzed between 466 and 524 K at about 475 Torr pure DMNA pressure in static cells. A radical mechanism was proposed and computer-modeled to account for the disappearance of DMNA and the production of (CH3)2NNO and CH3NO2. The rate constant for DMNA decomposition into (CH3)2N and NO2, based on these low-temperature results and other high-temperature shock tube data, covering 460–960 K, can be given by k1 = 1015.9±0.2 exp(−22,000±200/T) sec−1. This result leads to values for the N-N bond energy of 43.3±0.5 kcal/mole and the heat of formation of the (CH3)2N radical, 35±2 kcal/mole at 298 K. Kinetic modeling of the CH3NO2 and (CH3)2NNO production profiles has been carried out.

Irradiation of gaseous NO2 with the 488 nm line of an argon ion laser during its reaction with C2H4 over a Pt catalyst at 250 C resulted in up to a fourfold increase in the CO2 product yield. This enhancement is believed to result from the reaction of vibrationally excited NO2 with adsorbed C2H4 or a species derived from it. The observed effect disappeared after a period of time due to surface poisoning. Hydroxyl radicals have been detected leaving the surface of Pt and Rh-Pt catalysts during the reaction of H2 and 02 at 600-800 C. The OH radical was detected by its fluorescence at 340 nm induced by a dye laser, both in the gas phase and in an Ar matrix at 10 K. The activation energies for OH production from Pt and Rh-Pt surfaces have been determined.

Chemischer InformationsdienstVolume 10, Issue 36 Preparative Organic Chemistry ChemInform Abstract: MECHANISM OF HYDROGEN FLUORIDE PRODUCTION AND STIMULATED EMISSION FROM THE REACTION OF OXYGEN(3P) ATOMS WITH FLUOROETHENES M. E. UMSTEAD, M. E. UMSTEADSearch for more papers by this authorF. J. WOODS, F. J. WOODSSearch for more papers by this authorM. C. LIN, M. C. LINSearch for more papers by this author M. E. UMSTEAD, M. E. UMSTEADSearch for more papers by this authorF. J. WOODS, F. J. WOODSSearch for more papers by this authorM. C. LIN, M. C. LINSearch for more papers by this author First published: September 4, 1979 https://doi.org/10.1002/chin.197936141Read 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. Volume10, Issue36September 4, 1979 RelatedInformation

The laser has become one of the most useful and powerful tools in chemistry as well as in many other branches of science and technology, due to its intensity, monochromaticity and tunability. In the Chemistry Division at the Naval Research Laboratory, we have applied a variety of lasers to different areas of chemical research, from reaction dynamics to homogeneously catalyzed polymerization. In this presentation, we shall discuss the results of our recent studies in the following areas of applications.

The effect of CO2 laser radiation on the Pt-catalyzed decomposition of HCOOH has been investigated in a static reactor and in a low-pressure matrix isolation system. HCOOH is known to decompose on Pt by two reaction paths, one leading to CO2 + H2, and the other to CO + H2O. It was found in this study that the laser caused either a decrease in the rate of formation of both CO and CO2, or selectively decreased the yield of CO, depending upon the condition of the Pt surface. In the case of a clean Pt surface, a laser line that is strongly absorbed by HCOOH caused a decrease in the rate of formation of both CO and CO2. A nonabsorbed line had no effect. In the case of a Pt surface that had been partially poisoned by reaction products, the strongly absorbed line caused a selective decrease in CO formation, thus enhancing the CO2/CO product ratio by as much as 50%. The activation energy measured for HCOOH decomposition in the matrix isolation experiments is 3.5 ± 0.2 kcal/mole using a clean Pt surface under the low pressure conditions. Additionally, the 0=C-0-H radical has been identified by the use of deuterium substitution. The present results have demonstrated the possibility of combining the unique properties of both catalysts and lasers to drive chemical reactions in selected synthetic routes and also the utility of the matrix isolation technique for heterogeneous catalytic studies.

Chemischer InformationsdienstVolume 9, Issue 32 Reviews ChemInform Abstract: KINETICS AND MECHANISMS OF REACTIONS OF FLUOROMETHYLIDYNE, MONOFLUOROMETHYLENE, AND DIFLUOROMETHYLENE RADICALS D. S. Y. HSU, D. S. Y. HSUSearch for more papers by this authorM. E. UMSTEAD, M. E. UMSTEADSearch for more papers by this authorM. C. LIN, M. C. LINSearch for more papers by this author D. S. Y. HSU, D. S. Y. HSUSearch for more papers by this authorM. E. UMSTEAD, M. E. UMSTEADSearch for more papers by this authorM. C. LIN, M. C. LINSearch for more papers by this author First published: August 8, 1978 https://doi.org/10.1002/chin.197832351AboutPDF 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. Volume9, Issue32August 8, 1978 RelatedInformation

A technique has been developed for sampling systems dynamically at subambient pressures and injecting samples into a gas chromatograph. A gas sampling valve with a large sample loop is used. The sample is compressed into a small volume at one end of the loop by a secondary helium stream during injection. Peak resolution is not seriously impaired by use of the large sample loop.