Determination of rate constant for

Grover R, Decouzon M, Maria P-C and Gal J-F 1996 Reliability of Fourier transform-ion cyclotron resonance determinations of rate constants for ion/molecule reactions Eur. Mass Spectrom. 2 213-23... 

Fisher J J and McMahon T B 1990 Determination of rate constants for low pressure association reactions by Fourier transform-ion cyclotron resonance Int. J. Mass Spectrom. Ion. Proc 100 707-17... 

The kinetic data for the reaction of primary alkyl radicals (RCH2 ) with a variety of silanes are numerous and were obtained by applying the free-radical clock methodology. The term free-radical clock or timing device is used to describe a unimolecular radical reaction in a competitive study [2-4]. Three types of unimolecular reactions are used as clocks for the determination of rate constants for this class of reactions. The neophyl radical rearrangement (Reaction 3.1) has been used for the majority of the kinetic data, but the ring expansion rearrangement (Reaction 3.2) and the cyclization of 5-hexenyl radical (Reaction 3.3) have also been employed. 

Stable free radicals such as nitroxides have been used In correlation with EPR to study the effects of changes in pH and the determination of rate constants for spin exchange. 

Determinations of rate constants for the catalytic process were carried out by double potential step chronocoulometry... 

Determination of Rate Constants for the Self-Reactions of Peroxy Radicals by Electron Spin Resonance Spectroscopy... 

Gas-phase reactions which result in nucleophilic displacement at a saturated, or an unsaturated, carbon centre have been observed in positive and negative ion chemistry. By far, the most widely occurring case is the formal analog of the Sn2 reaction initially reported by Bohme and Young (1970). The experimental determination of rate constants for SN2 reactions has received a great deal of attention as has the mechanistic point of view including the interpretation of the potential energy surface for the gas-phase reaction. 

D.M. Himmelblau, C.R) Jones and K.B. Bischoff, Determination of rate constants for complex kinetic models, Ind. Eng. Chem. Fundamentals,... 

In each of these equations the constant sought is found from the slope of the straight line and the intercept on the ordinate axis, though the intercept b and the slope values will be different for every case. A conclusion may be drawn that the final concentration of primary or secondary products, or the sum of these, as functions of the initial substance concentration should be known for determination of rate constants for oxygen atom reactions. But it is not indispensable to determine whether the products are primary, secondary, or the sum of these. 

This chapter applies many of the techniques discussed in previous chapters to the determination of rate constants for complex reactions in solution. It also focuses on a variety of types of reaction in solution. 

We have found that sulfite and bisulfite undergo one-electron oxidation by many free radicals to produce S03. Rate constants determined for selected radicals are given in Table 1. Measurement of the rate constant over a wide range of pH has, in some cases, allowed the separate determination of rate constants for the oxidation of sulfite and bisulfite. The very strong oxidant OH reacts very rapidly and oxidizes bisulfite faster than sulfite, possibly due to a contribution from hydrogen atom abstraction. For radicals which are relatively weaker oxidants, the reaction with sulfite is the faster. For example, with Br2 the ratio of rate constants for sulfite to bisulfite is about 4 for the even weaker... 

Scwharz HA. Determination of rate constants for the radical processes in the radiation chemistry of water. J Phys Chem 1962 66 255-263. 

The accurate determination of rate constants for the reactions of 19F atoms is often hampered by the presence of reactive F2 and by the occurrence of side reactions. The measurement of the absolute concentration of F atoms is sometimes a further problem. The use of thermal-ized 18F atoms is not subject to these handicaps, and reliable and accurate results for abstraction and addition reactions are obtained. The studies of the reactions of 18F atoms with organometallic compounds are unique, inasmuch as such experiments have not been performed with 19F atoms. In the case of addition reactions, the fate of the excited intermediate radical can be studied by pressure-dependent measurements. The non-RRKM behavior of tetraallyltin and -germanium compounds is very interesting inasmuch as not many other examples are known. The next phase in the 18F experiment should be the determination of Arrhenius parameters for selected reactions, i.e., those occurring in the earth s atmosphere, since it is expected that the results will be more precise than those obtained with 19F atoms. 

Onstein P, Stefan MI, Bolton JR (1999) Competition Kinetics Method for the Determination of Rate Constants for the Reaction of Hydroxyl Radicals with Organic Pollutants Using the UV/H2O2 Advanced Oxidation Technology The Rate Constants for the tert-Butyl Formate Ester and 2,4-Di-nitrophenol,/. Adv. Oxid. Technol. 4, No. 2 231-236. 

Voevodsky. V. V., and V. N. Kondratiev, Determination of rate constants for elementary steps in branched chain reactions, in Progress in Reaction Kinetics, G. Porter, ed., 1, Pergamon, Oxford (1961), 43-65. 

Similar radiolytic yields of phenoxyl radicals have been fonnd in CH2CI2 solntions. The radiolysis of this solvent appeared to be simpler than that of CCLj and permitted determination of rate constants for reactions of Cl atoms. Both phenol and p-methoxyphenol react with diffusion-controlled rate constants (2.5 x 10 ° and 5 x... 

The kinetic NMR method permitted also the determination of rate constants for hydrogen transfer to cysteamine thiyi radicals from selected amino acids containing reactive side chains [91]. A summary of these rate constants is given in Table 3.2. Here, the rate constant represents the sum of the individual rate constants for hydrogen transfer from C-H [k o) and from the side chain C-H bonds (ksc), i.e., 1 32 = 1 30 T ksc-... 

As an example of a reaction system used for the determination of rate constants for the reaction of OH radicals with organics. Corse and Volman (123, 130) Irradiated H202-C0-02-reactant mixtures at 253.7 nm and monitored the rate of formation of CO2. Their proposed reaction scheme was... 

Alternate reaction systems for the determination of rate constants for the reaction of OH radicals with organics have been used by Campbell and co-workers (127, 131-133), Helcklen and co-workers (124, 134), and by Cox and co-workers (126, 135-137) these references should be consulted for detailed discussions of their methods. 

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