Bimolecular reactions 1012 INDEX

The bulk polymerization of acrylonitrile in this range of temperatures exhibits kinetic features very similar to those observed with acrylic acid (cf. Table I). The very low over-all activation energies (11.3 and 12.5 Kj.mole-l) found in both systems suggest a high temperature coefficient for the termination step such as would be expected for a diffusion controlled bimolecular reaction involving two polymeric radicals. It follows that for these systems, in which radicals disappear rapidly and where the post-polymerization is strongly reduced, the concepts of nonsteady-state and of occluded polymer chains can hardly explain the observed auto-acceleration. Hence the auto-acceleration of acrylonitrile which persists above 60°C and exhibits the same "autoacceleration index" as at lower temperatures has to be accounted for by another cause. 

A collision of two particle-reactants is needed for the bimolecular reaction to occur. In the condensed phase (both in the liquid and solid phase), this reaction occurs in two stages. At first particle-reactants, moving due to the molecular mobility of surrounding solvents particles of polymer segments, >proach each other at the reaction distance (get into the same cage )- Then they react with each other with the rate constant or diverge with the rate constant Vg (index D designates diffusion)... 

In a homologous series of OP compounds, increasing potency for AChE inhibition and cholinergic toxicity correlates with decreasing potency for NTE inhibition and OPIDN. The relative inhibitory potency (RIP) of an OP compound or its active metabolite for NTE versus AChE in vitro can be used as a convenient index of the probable neuropathic potential of the compound. A commonly used measure of inhibitory potency is the IC50, the concentration required to inhibit 50% of the enzyme activity under a standardized set of reaction conditions and time of incubation of the inhibitor with the enzyme preparation. A better measure of inhibitory potency is the bimolecular rate constant of inhibition, ki. When... 

The techniques for measuring rate constants and prodnct distribntion (branching ratios) for ion-molecule reactions are varied, but the majority of the data have been determined using the FA, drift-tube (DT), selected ion flow tube (SIFT), high-pressure mass spectrometric techniques, or ICR. These methods are detailed in Chap. 4. A number of surveys of all classes of ion-molecule reactions have appeared in the literature Ferguson [16], Sieck et al. [17], Albritton [18], Anicichet al. [19], Ikezoe et al. [20], some of which include termolecular reactions or are limited to selected methods. Anicich listed [21] an index to the hterature for gas phase bimolecular positive ion-molecule reactions as a comprehensive survey of ion-molecule reaction kinetics and product distribution of the reactions. Over 2300 references are cited. This index covers the hterature from 1936 to 2003. It was limited to selected reactions, listed by reactant ion, that were important for chemical modehng ionic processes in planetary atmospheres, cometary comas, and intersteUar clouds. 

Anicich VG. An index of the literature for bimolecular gas phase cation-molecule reaction kinetics. JPL Publication U.S. (03-19) 2003. p. 1172... 

Anicich, V.G., 2003. An Index of the Literature for Bimolecular Gas Phase Cation-Molecule Reaction Kinetics. Jet Propulsion I-aboratory—California Institute of Technology, Pasadena, CA, USA, p.ll94, JPI--Ihiblication-03-19. 

Anicich, V. G. (2003) An index of the literature for bimolecular gas phase cation-molecule reaction kinetics. JPL Publication, Jet Propulsion Laboratory, Pasadena, CA, pp. 03-19. Yamada, N., Takahashi, J., and Sakata, K. (2002) The effect of cell-gas impurities and kinetic energy discrimination in an octopole collision cell ICP-MS under non-thermalised conditions. J. Anal. At. Spectrom., 17,1213-22. 

---