ISSN:0538-8066    

DOI:10.1002/kin.550010102

出版商:John Wiley&Sons, Inc.    

年代:1969

数据来源: WILEY

摘要:

AbstractCCl and CC bond energies in the chloroethanes and CH, CCl, and CC bond energies in the chloroethyl radicals are calculated from known heats of formation of chloroethanes and chloroethylenes and known CH bond energies in chloroethanes.The results obtained show a dependence of bond energy on the isomeric structure of the molecules and radicals and on the type of bond broken (primary, secondary, or tertiary). Heats of formation and bond energies estimated from group property additivity rules are in close agreement with experime

ISSN:0538-8066    

DOI:10.1002/kin.550010103

出版商:John Wiley&Sons, Inc.    

年代:1969

数据来源: WILEY

摘要:

AbstractA study of the pressure dependence of the C5products from the reaction ofcis‐butene‐2 and methylene is reported. Methylene was produced by the photolysis of diazomethane with 4358 Å light at 23° or 56°, and by photolysis of ketene with 3200 Å radiation at 23° or 100°. The change with increasing pressure of the relative amounts of the characteristically “triplet products” (trans‐1,2‐dimethylcyclopropane,trans‐pentene‐2 (TP2), and 3‐methylbutene‐1 (3MB1)) and “singlet products” (cis‐1,2‐dimethylcyclopropane (CDMC) andcis‐pentene‐2 (CP2)) are discussed. The behavior is reminiscent of that found in3CH2‐cis‐butene‐2 systems and can be interpreted in terms of the rapid rate of rearrangement of an initial triplet diradical product component, due to3CH2, relative to the slower rate and readier collisional stabilization of an initial vibrationally‐excited dimethyl cyclopropane product component, due to1CH2. Relative rates of reactions of1CH2with allylic CH:vinyl CH:CC in the neat liquid were, for dia

ISSN:0538-8066    

DOI:10.1002/kin.550010104

出版商:John Wiley&Sons, Inc.    

年代:1969

数据来源: WILEY

摘要:

AbstractThe use of iodine monochloride (ICl) as a thermal source of chlorine atoms in known concentration is discussed with particular reference to the suppression, by large excesses of iodine, of the chain processes normally associated with chlorine atom reactions. The kinetics and mechanism of the reaction of ICl with hydrogen are presented in a study covering the temperature range 205–337°C, and the pressure ranges: ICl, 6–20 torr; I2, 3–13 torr; and H2, 9–520 torr. The reaction, followed spectrophotometrically in a static system, is shown to be homogeneous, first order in ICl and in H2, and inverse half‐order in I2, over several half‐lifetimes of the ICl, yielding HCl as the sole product. The rate data obtained in this work for the reactionare combined with the critically evaluated results of other workers in an Arrhenius plot covering the temperature range 286–730°C, and three orders‐of‐magnitude in the rate constant, yielding the results, logk1/(1/mole sec) = 10.68–5.26/θ, where θ = 2.303RTin kcal/mole. This value ofk1is lower by a factor of about two than that proposed in a recent review by Fettis and Knox, and is clearly at variance by a factor of two or more with the most recent da

ISSN:0538-8066    

DOI:10.1002/kin.550010105

出版商:John Wiley&Sons, Inc.    

年代:1969

数据来源: WILEY

摘要:

AbstractThe temperature‐jump method has been used to determine the nickel(II)‐ and cobalt(II)‐arginine complexation kinetics. In the pH range studied, the neutral form of the ligand, HL, is the attacking, as well as the complexed, ligand species. The reactions reported on are of the typewheren= 1, 2, 3 and M is Ni or Co. At 25° and ionic strength 0.1Mthe association rate constants are: for nickel(II)k1= 2.3 × 103(±20%),k2= 2.4 × 104(±20%),k3= 3.5 × 104(±40%)M−1sec−1; for cobalt(II)k1= 1.5 × 105(±20%),k2= 8.7 × 105(±20%),k3= 2.0 × 105(±40%)M−1sec−1. Arginine binds to metal ions less well than homologous chelating agents due to the electrostatic repulsion arising from the positively charged terminus of the zwitterion. Kinetically, the effect appears in the association rate constants with nickel reactions more stron

ISSN:0538-8066    

DOI:10.1002/kin.550010106

出版商:John Wiley&Sons, Inc.    

年代:1969

数据来源: WILEY

摘要:

AbstractThe spectrophotometric determination of the rate of iodine atom catalyzed geometrical isomerization of diiodoethylene in the gas phase from 502.8 to 609.1°K leads to a rate constant for the bimolecular reaction between I andtrans‐diiodoethylene of logkt−c(M−1sec−1) = 8.85 ± 0.12 − (11.01 ± 0.30)/θ. Estimates of the entropy and enthalpy change for the addition of I atoms totrans‐diiodoethylene (process a.b) lead to logKa.b(M−1) = −2.99 − 4.0/θ, and thus to logkc(sec−1) = logkt−c– logKab= 11.8 −7.0/θ for the rate constant for rotation about the single bond in the adduct radical. The theory for calculation of the rotation rate constant is presented and it is shown that while the exact value depends on the barrier height, a value of 6.8 kcal/mole for this quantity leads to logk(sec−1) = 11.8 −6.7/θ. The activation energy points to a better value of the group contribution to heat of formation of the groupC‐(I)2(H

ISSN:0538-8066    

DOI:10.1002/kin.550010107

出版商:John Wiley&Sons, Inc.    

年代:1969

数据来源: WILEY

摘要:

AbstractThe title reactions have been investigated in a fast flow system at pressures of about 2 torr and temperatures between 12 and 132°C. The following Arrhenius equations are derived for reaction (2)where the units ofk2are l/mole sec and ofE2, cal/mole, and the limits are the 95% confidence limits assuming random errors.These equations are in good agreement with those which can be derived from previous investigations

ISSN:0538-8066    

DOI:10.1002/kin.550010108

出版商:John Wiley&Sons, Inc.    

年代:1969

数据来源: WILEY

摘要:

AbstractThe method of molecular‐modulation spectrometry for studying photochemical reactions has been applied to methyl nitrite photolysis. The infrared absorption of the nitroxyl radical HNO has been observed in the gas phase at 3300 cm−1. Under the present experimental conditions the steady‐state concentration of HNO under steady illumination was 1.1 × 1012particles/cc, and the observed modulation amplitude was 4.5 × 1010particles/cc. At 25°C and 1 atm of nitrogen, the cross section for infrared absorption by HNO at 3300 cm−1is 1.7 × 10−19cm2. The rate constant ratiob/cwas found to be 8.0. From the literature value of the rate constantd, the observed rate constant for the reactionise= (5 ± 1) × 10−

ISSN:0538-8066    

DOI:10.1002/kin.550010109

出版商:John Wiley&Sons, Inc.    

年代:1969

数据来源: WILEY

摘要:

AbstractThe reaction between carbon monoxide and atomic oxygen was studied in a gas flow over a temperature range of 136 to 230°C at atmospheric pressure. The rate constant of this reaction, considered to be one for a second‐order reaction, was found to decrease with increasing temperature and to depend on the ratio of O2to CO that was varied from 0.11 to 2.69. A conclusion was made that under the experimental conditions the reaction was third orderThe rate constant of this reactionwas determined for a mixture of O2and CO and it was found that the efficiency of O2as particle M is four times that of

ISSN:0538-8066    

DOI:10.1002/kin.550010110

出版商:John Wiley&Sons, Inc.    

年代:1969

数据来源: WILEY

摘要:

AbstractRates of solvolysis of benzyl chloride and of substituted benzyl chlorides have been measured in an acetone‐water mixture (acetone mole fraction 0.147) at pressures ranging from atmospheric to 1 kbar. Pressure studies have also been made forp‐methyl benzyl chloride in various acetone‐water mixtures. Measurements have also been made of the partial molar volumes of the reactants. The plots of logkagainst pressure are fitted to a second‐degree polynomial inP, and values of ΔV‡and (δΔV//δP)Tare obtained. The ΔV‡values are all negative, having values ranging from −18 to −24 cc/mole. The results are interpreted on the view that the mechanisms areSN2(1), i.e. are towards theSN1 end of theSN2 spectrum of behavior. The ΔV‡values steadily become more negative in the seriespCH3, H,pCl,pNO2, and this is interpreted in terms of the greater spreading of positive charge in thepCH3case and in terms of greaterSN2(2) character in thepNO2case. The ΔV‡values go through a minimum as the solvent composition is varied, a result that is related to the existence of a corresponding maximum in the partial molar volumes of the reactant. The (δΔV‡/δP)Tvalues show a negative correlation with ΔV‡, suggesting, as expected, that the more compact acti

ISSN:0538-8066    

DOI:10.1002/kin.550010111

出版商:John Wiley&Sons, Inc.    

年代:1969

数据来源: WILEY