Bimolecular Reaction Rate Constants Research Articles

An evaluation of kinetic rate data for reactions of neutrals of atmospheric interest

A tabulation and analysis of bimolecular and termolecular rate constants for reactions involving atmospheric neutral species (H 2, O 2, N 2, H 2O, H, O, N, OH, HO 2, O 3, oxides of nitrogen, and hydrocarbons) is presented. The scant data available for reactions of vibrationally or electronically excited reactants is also included.

Computation of high-temperature rate constants for bimolecular reactions of combustion products

A procedure is presented for using available molecular data to compute the activation energies and rate constants of bimolecular transfer reactions for the halogen atoms. This computational method is also applied to calculating the kinetics for transfers of O, N, C, B, Be, and Al atoms bonded to univalent atoms. The procedure is based on modifications of the Johnston-Parr method of predicting kinetic data for hydrogen-atom transfer reactions. Potential energies of repulsion are calculated by using a reduced variable treatment of the Sato function. The procedure and results are also presented for computations of high-temperature rates of hydrogen-atom transfer reactions in which molecules containing a total of four atoms are involved. Computed rate constants are compared with experimental kinetic data when available, and agreement is generally satisfactory. Less than 0.1 minute of electronic-computer time per reaction is required to calculate the activation energy, vibrational parameters of the activated complex, rate constants at 25 temperatures (primarily in the 1000° to 4000°K range), and Arrhenius rate equation constants. Results are summarized for bimolecular atom-transfer reactions involving combustion products such as HF, HCl, HBr, HI, CF, CCl, BF, BCl, BeCl, ClO, AlCl, CH, OH, NH, AlH, BH, BeH, CH2, NH2, BH2, BeH2, H2O, HCO, HBO, HCN, AlOH, and NaOH.

Vibration, Excitation, and Molecular Dissociation of Gaseous Oxygen and Carbon Dioxide in a Shock Wave

Absorption spectroscopy techniques were employed for a shock tube study of the kinetics of the nonequilibrium processes at high temperatures. Ultraviolet absorption intensity as a function of time was investigated behind the shock front. Pure carbon dioxide, oxygen and mixtures of oxygen with nitrogen, argon, xenon, helium, nitrogen dioxide, water vapour and C2H5OH were studied.The experimental value of the vibrational relaxation time of oxygen at T = 1200–7000°K was in accordance with the results of Landau-Teller theory; at T<2000°K, a significant difference was observed between our data and Blackman's well-known results.Dissociation of O2 and CO2 molecules occurs as a bimolecular reaction and dissociation rate constants are approximated by the following expressions: kd(O2, O2)= 4·6×109(T)1/2(D/RT)4exp(−D/RT) cm3/mol.sec (T = 2600–7000°K, D = 119 kcal⧸mol.); kd(CO2, CO2) =3×107(T)1/2(D/RT)6exp (−D/RT) cm3/mol.sec (T = 3000–5500°K, D =126 kcal/mol).

Studies on Decomposition and Stabilization of Drugs in Solution. XI. Overall Velocity Constants for Succinylmonocholine Chloride Hydrolysis as a Function of pH.

1) The degradative reaction of succinylmonocholine chloride, the first hydrolytic product of succinylcholine chloride, was investigated over the whole pH range of 0.5 to 8.5 from the standpoint of chemical kinetics. The degradation is an apparent monomolecular reaction at a fixed pH value.2) The decomposition may be accounted for by the six rate constants of bimolecular reaction and the dissociation constant of succinylmonocholine chloride. The rate (hr.-1) of reaction at 60° can be practically represented by_??_The relatively slight variation in k caused by buffer effect as compared with succinylcholine chloride was recognized.3) The hydrolysis of succinylcholine chloride in aqueous solution at a fixed pH value was fitted to a kinetic expression for a consecutive reaction with two first-order reactions. A good agreement was obtained between calculated and experimental values.

The rate constant of the bimolecular reaction between hydrogen peroxide and ferrous ion.

Die Geschwindigkeitskonstante der bimolekularen Reaktion zwischen Wasserstoffsuperoxyd und Ferroion wurde mittels einer spektrophotometrischen Methode in einem relativ weiten Konzentrationsbereich der Reaktionsteilnehmer und der Aziditat gemessen. Im Temperaturintervall von 15 bis 40°C kann die Geschwindigkeitskonstante durch den Ausdruck: $$k_1 = 1,05 \cdot 10^8 \cdot \exp .( - 8460/RT)1 \cdot mole^{ - 1} \cdot \sec .^{ - 1} $$ in befriedigender Weise dargestellt werden. Die Aktivierungsenergie (8460 cal) ist in guter Ubereinstimmung mit dem fruher gefundenen Wert vonHaber undWeiss; der Koeffizient der Exponentialfunktion ist etwa doppelt so gross als fruher gefunden.