Kinetics of phenyl radical reactions with ethane and neopentane: Reactivity of C6H5 toward the primary C‐H bond of alkanes

The kinetics of C₆H₅ reactions with C₂H₆ (1) and neo‐C₅H₁₂ (2) have been studied by the pulsed laser photolysis/mass spectrometric method using C₆H₅COCH₃ as the phenyl precursor at temperatures between 565 and 1000 K. The rate constants were determined by kinetic modeling of the absolute yields of C₆H₆ at each temperature. Another major product, C₆H₅CH₃, formed by the recombination of C₆H₅ and CH₃, could also be quantitatively modeled using the known rate constant for the reaction. A weighted least‐squares analysis of the two sets of data gave k₁ = 10^11.32±0.05 exp[−(2236 ± 91)/T] cm³ mol⁻¹ s⁻¹ and k₂ = 10^11.37±0.03 exp[−(1925 ± 48)/T] cm³ mol⁻¹ s⁻¹ for the temperature range studied. The result of our sensitivity analysis clearly supports that the yields of C₆H₆ and C₆H₅CH₃ depend primarily on the abstraction reactions and C₆H₅ + CH₃, respectively. From the absolute rate constants for the two reactions we obtained the value for the H‐abstraction from a primary C‐H bond, k‐CH = 10^10.40±0.06 exp(−1790 ± 102/T) cm³ mol⁻¹ s⁻¹. This result is utilized for analysis of other kinetic data measured for C₆H₅ reactions with alkanes in solution as well as in the gas phase. © 2000 John Wiley & Sons, Inc. Int J Chem Kinet 33: 64–69, 2001     

Kinetics of C6H5 radical reactions with 2‐methylpropane, 2,3‐dimethylbutane and 2,3,4‐trimethylpentane

The absolute bimolecular rate constants for the reactions of C₆H₅ with 2‐methylpropane, 2,3‐dimethylbutane and 2,3,4‐trimethylpentane have been measured by cavity ringdown spectrometry at temperatures between 290 and 500 K. For 2‐methylpropane, additional measurements were performed with the pulsed laser photolysis/mass spectrometry, extending the temperature range to 972 K. The reactions were found to be dominated by the abstraction of a tertiary C H bond from the molecular reactant, resulting in the production of a tertiary alkyl radical: C₆H₅ + CH(CH₃)₃ → C₆H₆ + t‐C₄H₉ (1) (1) C₆H₅ + (CH₃)₂CHCH(CH₃)₂ → C₆H₆ + t‐C₆H₁₃ (2) (2) C₆H₅ + (CH₃)₂CHCH(CH₃)CH(CH₃)₂ → C₆H₆ + t‐C₈H₁₇ (3) (3) with the following rate constants given in units of cm³ mol⁻¹ s⁻¹: k₁ = 10^{(11.45 ± 0.18)} e^{−(1512 ± 44)/T} k₂ = 10^{(11.72 ± 0.15)} e^{−(1007 ± 124)/T} k₃ = 10^{(11.83 ± 0.13)} e^{−(428 ± 108)/T} © 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 645–653, 1999     

Kinetics of phenyl radical reactions with propane,n‐butane,n‐hexane,and n‐octane: Reactivity of C6H5 toward the secondary C?H bond of alkanes

The kinetics of C₆H₅ reactions with n‐C_nH_2n+2 (n = 3, 4, 6, 8) have been studied by the pulsed laser photolysis/mass spectrometric method using C₆H₅COCH₃ as the phenyl precursor at temperatures between 494 and 1051 K. The rate constants were determined by kinetic modeling of the absolute yields of C₆H₆ at each temperature. Another major product C₆H₅CH₃ formed by the recombination of C₆H₅ and CH₃ could also be quantitatively modeled using the known rate constant for the reaction. A weighted least‐squares analysis of the four sets of data gave k (C₃H₈) = (1.96 ± 0.15) × 10¹¹ exp[?(1938 ± 56)/T], and k (n‐C₄H₁₀) = (2.65 ± 0.23) × 10¹¹ exp[?(1950 ± 55)/T] k (n‐C₆H₁₄) = (4.56 ± 0.21) × 10¹¹ exp[?(1735 ± 55)/T], and k (n?C₈H₁₈) = (4.31 ± 0.39) × 10¹¹ exp[?(1415 ± 65)T] cm³ mol^?1 s^?1 for the temperature range studied. For the butane and hexane reactions, we have also applied the CRDS technique to extend our temperature range down to 297 K; the results obtained by the decay of C₆H₅ with CRDS agree fully with those determined by absolute product yield measurements with PLP/MS. Weighted least‐squares analyses of these two sets of data gave rise to k (n?C₄H₁₀) = (2.70 ± 0.15) × 10¹¹ exp[?(1880 ± 127)/T] and k (n?C₆H₁₄) = (4.81 ± 0.30) × 10¹¹ exp[?(1780 ± 133)/T] cm³ mol^?1 s^?1 for the temperature range 297‐‐1046 K. From the absolute rate constants for the two larger molecular reactions (C₆H₅ + n‐C₆H₁₄ and n‐C₈H₁₈), we derived the rate constant for H‐abstraction from a secondary C? H bond, k_s?CH = (4.19 ± 0.24) × 10¹⁰ exp[?(1770 ± 48)/T] cm³ mol^?1 s^?1. © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 36: 49–56, 2004     

Quenching of *UF6 (A state) by alkanes

The removal of *UF₆ (A state) molecules by selected alkanes has been investigated at 25°C. The following rate constants (units of 10¹¹ l/mol·sec) were evaluated: iso-C₄F₁₀, 0.0432 ± 0.0115; n-C₄F₁₀, 0.0764 ± 0.020; C₂F₆, 0.0192 ± 0.0052; CH₄, 0.0612 ± 0.0061; C₂H₆, 3.78 ± 0.60; C₃H₈, 5.08 ± 0.60; n-C₄H₁₀, 5.05 ± 0.78; iso-C₄H₁₀, 4.17 ± 1.15; neo-C₅H₁₂, 6.59 ± 0.93; CF₃? CH₃, 0.0385 ± 0.0056; CF₂H? CF₂H, 0.0729 ± 0.0074; and CF₂H? CFH₂, 0.149 ± 0.015. The perfluoro-alkane quenching of *UF₆ proceeds via a physical mechanism. The other alkane quenching reactions are consistent with a chemical mechanism also contributing in varying degrees which may involve removal of two hydrogens from the alkane.     

Deactivation of I(52P1/2) by CF3I,CH3I,C2H5I,and CH4

The technique of laser photolysis of alkyl and perfluoroalkyl iodides at 266 nm followed by time-resolved detection of the 1.3-μm emission from I^*(²P_1/2) has been used to measure the rate constants for deactivation of I^* by CH₃I, C₂H₅I, CF₃I, and CH₄. The recommended values are (2.76± 0.22) × 10^?13, (2.85 ± 0.40) × 10^?13, (3.5 ± 0.5) × 10^?17, and (7.52 ± 0.12) × 10^?14, respectively, in units of cm³ molecule^?1 S^?1.     

Relations between the electrosorption and the inhibition behaviour of homologous dialkyl-phenyl-phosphine oxides

The electrode transfer reaction of Cd²⁺ has been studied under the influence of the homologous dialkyl-phenyl-phosphine oxides (R)₂·C₆H₅·PO (R=CH₃, C₂H₅, C₃H₇, C₄H₉, C₅H₁₁) using d.c. polarography. The rate constants were correlated with the adsorption data. The comparison of the rate constants with the surface pressure values shows that the rate constants decrease linearly with increasing surface pressure values. It could also be shown that the inhibitory effect grows as the length of the alkyl groups increases.     

13C NMR spectra of metal σ-cyclopentadienyls

Proton decoupled ¹³C NMR spectra have been measured for the cyclopentadienyl compounds C₅H₅Si(CH₃)_nCl_3?n(n = 1, 2, 3), C₅H₅Ge(CH₃)₃, CH₃C₅H₄Ge(CH₃)₃, C₅H₅Sn(CH₃)₃, σ-C₅H₅Fe(CO)₂-π-C₅H₅ and C₅H₅HgCH₃. A fast metallotropic rearrangement occurring in the compounds causes the spectra to be temperature dependent for the Si, Ge, Sn and Fe derivatives. For the derivatives of silicon or germanium, the olefinic signals are unsymmetrically broadened by the 1,2-shift at lower migration rates. Line widths of the ring carbon signals have been measured to give an estimate for the activation parameters of the rearrangement in C₅H₅Ge(CH₃)₃ (E_a = 10·7 ± 0·9 kcal/mole, ΔG^? = 13·4 ± 0·9 kcal/mole) and C₅H₅Sn(CH₃)₃ (E_a = 6·8 ± 0·7 kcal/mole, ΔG^? = 7·1 ± 0·7 kcal/mole). At room temperature, the spectrum of C₅H₅HgCH₃ displays just one narrow signal responsible for the cyclopentadienyl ligand. The spectrum of CH₃C₅H₄Ge(CH₃)₃ at –30° demonstrates that two isomers containing methyl in the vinylic position are present, the ratio being ca. 2:1. The ¹³C spectra of the vinylic isomers have been analysed in the case of C₅H₅Si(CH₃)_nCl_3?n.     

Reactions of the copper dimer,Cu2, in the gas phase

Reactions of Cu₂ with several small molecules have been studied in the gas phase, under thermalized conditions at room temperature, in a fast-flow reactor. They fall into one of two categories. Cu₂ does not react with O₂, N₂O, N₂, H₂, and CH₄ at pressures up to 6 torr. This implies bimolecular rate constants of less than 5 × 10^?15 cm³ s^?1 at 6 torr He. Cu₂ reacts with CO, NH₃, C₂H₄, and C₃H₆ in a manner characteristic of association reactions. Second-order rate constants for all four of these reagents are dependent on total pressure. The reactions with CO, NH₃, and C₂H₄ are in their low pressure limit at up to 6 torr He buffer gas pressure. The reaction with C₃H₆ begins to show fall-off behavior at pressures above 3 torr. Limiting low-pressure, third-order rate constants are 0.66 ± 0.10, 8.8 ± 1.2, 9.3 ± 1.4, and 85 ± 15 × 10^?30 cm⁶ s^?1 in He for CO, NH₃, C₂H₄, and C₃H₆, respectively. Modeling studies of these rate constants imply that the association complexes are bound by at least 20 kcal mol^?1 in the case of C₂H₄ and C₃H₆ and at least 25 kcal mol^?1 in the other cases. The implications of these results for Cu-ligand bonding are developed in comparison with existing work on the interactions of these ligands with Cu atoms, larger clusters, and surfaces. © 1994 John Wiley & Sons, Inc.     

Selected rate constants for H,O, N,and Cl atoms with substrates at room temperatures

Rate constants for H + Cl₂, H + CH₃CHO, H + C₃H₄, O + C₃H₆, O + CH₃CHO, and Cl + CH₄ have been measured at room temperature by the discharge flow—resonance fluorescence technique. The results are (1.6 ± 0.1) × 10^?11, (9.8 ± 0.8) × 10 ^?14, (6.3 ± 0.4) × 10^{?13) (2.00 torr He), (3.95 ± 0.41) × 10?12, (4.9 ± 0.5) × 10|su?13} and (1.08 ± 0.07) × 10^?13, respectively, all in units of cm³ molecule^?1 s^?1. Also N atom reactions with C₂H₂, C₂H₄, C₃H₄, and C₃H₆ were studied but in no case was there an appreciable rate constant. These results are compared to previous studies.     

Rate constants for the elementary reactions between CN radicals and CH4, C2H6, C2H4, C3H6, and C2H2 in the range: 295 ⩽ T/K ⩽ 700

Pulsed laser photolysis, time-resolved laser-induced fluorescence experiments have been carried out on the reactions of CN radicals with CH₄, C₂H₆, C₂H₄, C₃H₆, and C₂H₂. They have yielded rate constants for these five reactions at temperatures between 295 and 700 K. The data for the reactions with methane and ethane have been combined with other recent results and fitted to modified Arrhenius expressions, k(T) = A′(298) (T/298)ⁿ exp(?θ/T), yielding: for CH₄, A′(298) = 7.0 × 10^?13 cm³ molecule^?1 s^?1, n = 2.3, and θ = ?16 K; and for C₂H₆, A′(298) = 5.6 × 10^?12 cm³ molecule^?1 s^?1, n = 1.8, and θ = ?500 K. The rate constants for the reactions with C₂H₄, C₃H₆, and C₂H₂ all decrease monotonically with temperature and have been fitted to expressions of the form, k(T) = k(298) (T/298)ⁿ with k(298) = 2.5 × 10^?10 cm³ molecule^?1 s^?1, n = ?0.24 for CN + C₂H₄; k(298) = 3.4 × 10^?10 cm³ molecule^?1 s^?1, n = ?0.19 for CN + C₃H₆; and k(298) = 2.9 × 10^?10 cm³ molecule^?1 s^?1, n = ?0.53 for CN + C₂H₂. These reactions almost certainly proceed via addition-elimination yielding an unsaturated cyanide and an H-atom. Our kinetic results for reactions of CN are compared with those for reactions of the same hydrocarbons with other simple free radical species. © John Wiley & Sons, Inc.     

Reactivities of N-alkylitaconimides in radical copolymerizations with styrene or methyl methacrylate

The radical copolymerizations of N-alkylitaconimide (RII, R = CH₃, C₂H₅, n-C₃H₇, i-C₃H₇, n-C₄H₉, i-C₄H₉, CH₂CH₂Cl, CH₂C₆H₅) (M₁) with styrene (ST) (M₂) or methyl methacrylate (MMA)-(M₂) were carried out at 60°C, using azobisisobutyronitrile as an initiator in tetrahydrofuran in order to clarify the substituent effect on the copolymerizations. The monomer reactivity ratios r₁, r₂ and the Q₁ and e₁ values were determined from the results obtained. It was found that the relative reactivities 1/r₂ of RII toward an attack by a poloystyryl radical could be correlated not by the steric-substituent constant E_s of the alkyl group in RII but by the polar-substituent constant σ^* in Taft's equation: log(1/r₂) = ρ^*σ^* + δ E_s. According to the above equation, the ρ^* and δ values were obtained as 0.55 and 0, respectively, in the RII-ST system, while in the RII-MMA system, the ρ^* and δ values were obtained as 0.49 and 0, respectively. It was also observed that the Q₁values for RII were proportional to σ^* constants and that the e₁ values for RII were independent of σ^* substituent constant. It was also found that the weight-average molecular weights of the copolymers are between 8.5 × 10⁴ and 32.5 × 10⁴.     

Kinetics of interaction of vibrationally excited OH(X2πi)v=9 with simple hydrocarbons at room temperature

Relative rate constants for the removal of vibrationally excited OH in the ninth vibrational level of its ground electronic state [designated hereafter by OH? (9)] by interaction with a series of simple hydrocarbons at room temperature are reported. The reaction of hydrogen atoms with ozone was used to generate OH?(9) in a fast flow discharge system at 1.1 ± 0.1 torr total pressure. The decrease in the (9 → 3 band) Meinel band chemiluminescent emission intensity at 626 nm was followed as a function of the concentration of added organic or of a reference deactivator (O₂), respectively, at a fixed reaction time; these data gave relative rate constants, k/k, for the removal of OH?(9) by the organic. The relative rate constants determined in this study are as follows: C₂H₆, 2.7 ± 0.2; C₃H₈, 4.4 ± 0.4; n–C₄H₁₀, 7.5 ± 0.6; iso–C₄H₁₀, 7.3 ± 0.8; n–C₅H₁₂, 10.4 ± 0.7; C₂H₄, 22.9 ± 1.8; C₃H₆, 43.4 ± 1.4; cis–2–C₄H₈, 47.7 ± 3.1; C₆H₆, 29 ± 7. (Errors are two standard deviations of the weighted mean of experiments in two flow tubes with different wall coatings and carrier gases.) The implications of the trends in these rate constants for the relative contributions of energy transfer and reaction to the net removal of OH? (9) are discussed.     

Rates of OH radical reactions. XII. The reactions of OH with c?C3H6, c?C5H10, and c?C7H14. Correlation of hydroxyl rate constants with bond dissociation energies

Absolute rate constants for H-atom abstraction by OH radicals from cyclopropane, cyclopentane, and cycloheptane have been determined in the gas phase at 298 K. Hydroxyl radicals were generated by flash photolysis of H₂O vapor in the vacuum UV, and monitored by time-resolved resonance absorption at 308.2 nm [OH(A²Σ⁺→X²Π)]. The rate constants in units of cm³ mol⁻¹ s⁻¹ at the 95% confidence limits were as follows: k(c C₃H₆) = (3.74 ± 0.83) × 10¹⁰, k(c C₅H₁₀) = (3.12 ± 0.23) × 10¹², k(c C₇H₁₄) = (7.88 ± 1.38) × 10¹². A linear correlation was found to exist between the logarithm of the rate constant per C H bond and the corresponding bond dissociation energy for several classes of organic compounds with equivalent C H bonds. The correlation favors a value of D(c C₃H₅–H) = (101 ± 2) kcal mol⁻¹.     

The √t law in solid-phase reactions. Analysis of the hypothesis on rate constant distribution

The reaction C₂H₅ + O₂ → C₂H₅O₂ in glassy methanol-d₄ and the H-atom abstraction by CH₃, C₂H₅, and n-C₄H₉ radicals in C₂H₅OH + C₂D₅OH and CD₃CH₂OH + C₂D₅OH glassy mixtures have been studied by electron spin resonance. The analysis of the dependence of the reaction rates on the concentration of O₂ (oxidation) and C₂H₅OH, CD₃CH₂OH (H-atom abstraction) has shown that the √t law is not conditioned by the existence of regions characterized by different rate constants.     

Solvent effect in the polymerization of e-caprolactone initiated with diethylaluminum ethoxide

Kinetics of ϵ-caprolactone (ϵCL) polymerization initiated with diethylaluminum ethoxide in benzene (C₆H₆) and acetonitrile (CH₃CN) as solvents was studied and compared with the previously studied polymerization conducted in tetrahydrofuran (THF) solvent. Kinetic data were analyzed in terms of the kinetic scheme: “propagation with aggregation,” assuming that actually propagating active species (P_n*) aggregate reversibly into the unreactive (dormant) species . The determined equilibrium constants of deaggregation (K_da) decrease with decreasing solvent polarity, namely K_da (in mol²·L⁻²) = (1.3 ± 0.7)·10⁻² (CH₃CN), (1.8 ± 0.5)·10⁻⁵ (THF), (4.1 ± 0.7)·10⁻⁶(C₆H₆), whereas for the rate constants of propagation the opposite is true, k_p (in mol⁻¹·L·s⁻¹) = (7.5 ± 0.3)·10⁻³ (CH₃CN), (3.87 ± 0.01)·10⁻² (THF), (8.6 ± 0.9)·10⁻² (C₆H₆) (25°C). The latter effect is explained by a specific solvation (the stronger the higher solvent polarity) of the active species already in the ground state in the elementary reaction of the poly(ϵCL) chain growth: C₂H₅[OC(O)(CH₂)₅]_nO(SINGLE BOND)Al(C₂H₅)₂ + ϵCL → C₂H₅[OC(O)(CH₂)₅]_n+1O(SINGLE BOND)Al(C₂H₅)₂. © 1996 John Wiley & Sons, Inc.     

Optisch aktive übergangsmetall-komplexe LXIV. Neue optisch aktive Cp(CO)Fe-acyl-komplexe mit

The novel complexes CpFe(CO)(COR)P(C₆H₅)₂NR'R^* with Cp = C₅H₅,C₉H₇ (indenyl); R = CH₃, C₂H₅, CH(CH₃)₂, CH₂C₆H₅;R` = H, CH<sub>3</sub>, C<sub>2</sub>H<sub>5</sub>, CH<sub>2</sub>C<sub>6</sub>H<sub>5</sub> and R<sup>*</sup> = (S)-CH(CH<sub>3</sub>)(C<sub>6</sub>H<sub>5</sub>), have been synthesized by reaction of CpFe(CO)<sub>2</sub>R wiht P(C<sub>6</sub>H<sub>5</sub>)<sub>2</sub>NR`R^* and characterized analytically as well as spectroscopically. The pairs of diastereoisomers RS/SS have been separated by preparative liquid chromatography and fractional crystallization, respectively. The optically pure complexes (+)₄₃₆- und ()₄₃₆-CpFe(CO)(COR)P(C₆H₅)₂NR`R^* are configurationally stable at room temperature. At higher temperatures they equilibrate with CpFe(CO)₂R and epimerize with respect to the Fe configuration.     

Kinetics of the reactions of the IO radical with dimethyl sulfide,methanethiol, ethylene,and propylene

The reactions of IO radicals with CH₃SCH₃, CH₃SH, C₂H₄, and C₃H₆ have been studied using the discharge flow method with direct detection of IO radicals by mass spectrometry. The absolute rate constants obtained at 298 K are the following: IO + CH₃SCH₃ → products (1): k₁ = (1.5 ± 0.2) × 10^?14; IO + CH₃SH → products (2): k₂ = (6.6 ± 1.3) × 10^?16; IO + C₂H₄ →products (3): k₃ < 2 × 10^?16; IO + C₃H₆ → products (4): k₄ < 2 × 10^?16 (units are cm³ molecule^?1 s^?1). CH₃S(O)CH₃ and HOI were found as products of reactions (1) and (2), respectively. The present lower value of k₁ compared to our previous determination is discussed.     

Very-low-pressure pyrolysis of nitroso- and pentafluoronitrosobenzene C?NO bond dissociation energies

The high-pressure absolute rate constants for the decomposition of nitrosobenzene and pentafluoronitrosobenzene were determined using the very-low-pressure pyrolysis (VLPP) technique. Bond dissociation energies of DH⁰(C₆H₅? NO) = 51.5 ± 1 kcal/mole and DH⁰ (C₆F₅? NO) = 50.5 ± 1 kcal/mole could be deduced if the radical combination rate constant is set at log k_r(M^?1·sec^?1) = 10.0 ± 0.5 for both systems and the activation energy for combination is taken as 0 kcal/mole at 298°K. δH_f⁰(C₆H₅NO), δH_f⁰(C₆F₅NO), and δH_f⁰(C₆F₅) could be estimated from our kinetic data and group additivity. The values are 48.1 ± 1, –160 ± 2, and – 130.9 ± 2 kcal/mole, respectively. C–X bond dissociation energies of several perfluorinated phenyl compounds, DH⁰(C₆F₅–X), were obtained from the reported values of δH_f⁰(C₆F₅X) and our estimated δH_f⁰(C₆F₅) [X = H, CH₃, NO, Cl, F, CF₃, I, and OH].     

A kinetic and product study of the gas-phase reaction of ozone with vinylcyclohexane and methylene cyclohexane

The gas-phase reaction of ozone with vinylcyclohexane and methylene cyclohexane has been investigated at ambient T and p=1 atm of air in the presence of sufficient cyclo-hexane or 2-propanol added to scavenge OH. The reaction rate constants, in units of 10⁻¹⁸ cm³ molecule⁻¹ s⁻¹, are 7.52±0.97 for vinylcyclohexane (T=292±2 K) and 10.6±1.9 for methylene cyclohexane (T=293±2 K). Carbonyl reaction products were cyclohexyl meth-anal (0.62±0.03) and formaldehyde (0.47±0.04) from vinylcyclohexane and cyclohexanone (0.55±0.10) and formaldehyde (0.60±0.05) from methylene cyclohexane, where the yields given in parentheses are expressed as carbonyl formed, ppb/reacted ozone, ppb. The sum of the yields of the primary carbonyls is close to the value of 1.0 that is consistent with the simple mechanisms: O₃+cyclo(C₆H₁₁)−CH(DOUBLEBOND)CH₂→α(HCHO+cyclo(C₆H₁₁)CHOO)+(1−α)(HCHOO+cyclo(C₆H₁₁)CHO) for vinylcyclohexane and O₃+(CH₂)₅C(DOUBLEBOND)CH₂→α(HCHO +(CH₂)₅COO)+(1−α)(HCHOO+(CH₂)₅C(DOUBLEBOND)O) for methylene cyclohexane. The coefficients α are 0.43±0.10 for vinylcyclohexane and 0.52±0.05 for methylene cyclohexane, i.e., (formaldehyde+the substituted biradical) and (HCHOO+cyclohexyl methanal or cyclo-hexanone) are formed in ca. equal yields. Reaction rate constants, carbonyl yields, and reaction mechanisms are compared to those for alkene structural homologues. © 1997 John Wiley & Sons, Inc. Int J Chem Kinet 29: 855–860, 1997     

An ftir study of the reaction between nitrogen dioxide and alcohols

The reaction 2NO₂ + ROH = RONO + HNO₃ (R = CH₃ or C₂H₅) has been studied using the FTIR method at reactant pressures from 0.1 to 1.0 torr at 25°C. The termolecular rate constant for the forward reaction was determined to be (5.7 ± 0.6) × 10^?37 cm⁶/molec²·s for CH₃OH and (5.7 ± 0.8) × 10^?37 cm⁶/molec²·s for C₂H₅OH, that is, d[RONO]/dt = k[NO₂]²[ROH]. The corresponding equilibrium constants were measured as 1.36 ± 0.06 and 0.550 ± 0.025 torr^?1, respectively. These results are consistent with those of a previous study based on the NO₂ decay measurements at reactant pressures from 1 to 10 torr.