Induction chemical

It has been well known for a long time that some reactions taking place at a very slow rate may be markedly accelerated by the simultaneous occurrence of another reaction of measurable velocity. On the suggestion of Kessler this phenomenon is called chemical induction and it is said that the reaction of measurable velocity induces the other slow reaction. 

Summarizing, it can be said that induced reactions are connected mostly with oxidation-reduction processes and that this is true for the induced complex formation, too. On the other hand, induced precipitation has nothing to do with genuine induced reactions therefore it is advisable not to use this collective name in order to keep the concept of chemical induction clear. 

Although in the fifties of the last century it had already been recognized that in several oxidation-reduction reactions the co-existence principle i.e. the assumption that the individual processes take place independently of each other) was not valid and to date many examples of chemical induction have been found, there are only a few cases known where the mechanism of the induced reaction has been satisfactorily elucidated. There are several reasons for this. Some of the induced reactions take place too rapidly to be investigated by conventional kinetical methods in other cases a thorough investigation was frustrated by the lack of appropriate analytical methods. 

Chemical analysis of composite systems is often severely restricted by the invalidity of the co-existence principle (although there are a few cases known in which estimations are made possible just because of the occurrence of chemical induction). Therefore, many efforts have been directed at exploring at least qualitatively the source of errors caused by induced reactions. That is why our present knowledge about such reactions is rather qualitative in nature. 

The observation of induced reactions involving chromate almost coincided with the discovery of the phenomenon of chemical induction itself. According to the the role of chromate ions in these reactions, two groups can be distinguished (i) Chromium(VI) plays the role of actor, whose reaction with various inductors listed in Table 1 results in the oxidation of several acceptor ions or molecules. 

This short and far from complete survey shows that the previously obscure field of chemical induction is becoming more and more understood. The accelerating pace of progress has furnished from the forties onwards a great deal of interesting information about the chemistry of unstable intermediates, e.g. chromium(V), chromium(IV), arsenic(IV), tin(III), HO2, OH, SO4 radicals. These results were obtained mostly by conventional methods. Therefore, it may be expected that the more extensive application of methods suitable for detection and estimation of short-living entities (e.g. resonance methods, fast reaction techniques) will enable our somewhat qualitative knowledge (as it is today) to be put onto a quantitative basis. 

Ramel C. Magnusson J. 1979. Chemical induction of nondisjunction in Drosophila. Environ Health Perspect 3 59-66. 

The phenomenon of chemical induction was intensively studied by Jorissen [33-37]. He discovered that indigo was not oxidized by dioxygen but was simultaneously oxidized in the presence of oxidized triethylphosphine or benzaldehyde. He measured the factor of chemical induction in these reactions as equal to unity. Later, he proved that the oxidation product of benzaldehyde, benzoic peracid, did not oxidize indigo under conditions of experiment. This shows that a very active intermediate was formed during the oxidation of benzaldehyde and that it was not perbenzoic acid. Engler assumed peroxide to be in two forms, namely, an active moloxide A02 and a more stable peroxide. A new correct interpretation of chemical induction in oxidation reactions was provided later by the chain theory of oxidation of organic compounds (see later). 

Chu, E.H.Y. and Mailing, H.U. (1968). Mammalian cell genetics. II. Chemical induction of specific lucus mutations in Chinese hamster cells in vitro. Proc. Nat. Acad. Sci. U.S.A. 61 1306-1312. 

In many practical systems, one cannot distinguish the two stages in the ignition process since To> t, thus the time that one measures is predominantly the chemical induction period. Any errors in correlating experimental ignition data in this low-temperature regime are due to small changes in rt. 

White RD. 1982. Chemical induction of genetic injury The bioactivation of 1,2-dibromoethane. Diss Abstr Int 43 696-698. 

Another route to a methyl-branched derivative makes use of reductive cleavage of spiro epoxides ( ). The realization of this process was tested in the monosaccharide series. Hittig olefination of was used to form the exocyclic methylene compound 48. This sugar contains an inherent allyl alcohol fragmenC the chiral C-4 alcohol function of which should be idealy suited to determine the chirality of the epoxide to be formed by the Sharpless method. With tert-butvl hydroperoxide, titanium tetraisopropoxide and (-)-tartrate (for a "like mode" process) no reaction occured. After a number of attempts, the Sharpless method was abandoned and extended back to the well-established m-chloroperoxybenzoic acid epoxida-tion. The (3 )-epoxide was obtained stereospecifically in excellent yield (83%rT and this could be readily reduced to give the D-ribo compound 50. The exclusive formation of 49 is unexpected and may be associated with a strong ster chemical induction by the chiral centers at C-1, C-4, and C-5. 

Biancifiori C, Caschera F The relation between pseudo-pregnancy and the chemical induction hy four carcinogens of mammary and ovarian tumours in BALB/c mice. Br J Cancer 16 722-730, 1962... 

Taylor, J.L., and S.E. Grossberg, Chemical induction of interferon caroxymethy-lacridanone and other low molecular weight chemicals. Tex Rep Biol Med, 1982. 41 158-62. 

Multiple premalignant stages are apparent during chemical induction of skin and liver cancer (Farber, 1984), and multistage processes have been identified also in experimental lung (Yarita et colon cancer (Thumherr et al., 1973) as well. In chemically initiated mouse skin... 

Arcos, J.C. and Argus, M.F. (1974) Chemical Induction of Cancer. Structural Bases and Biologic Mechanism, Vol. IIA, Polynuclear Aromatic Hydrocarbons, Academic Press, New York. 

Schoneich, J., Michaelis, A. Rieger, R. (1970) Caffeine and the chemical induction of chromatid aberrations in Vida faba and ascite tumours of the mouse. Biol. Zentralbl., 88, 49-63 (in German)... 

Khan, M.A. Heddle, J.A. (1991) Chemical induction of somatic gene mutations and chromosomal aberrations in lung fibroblasts of rats. Mutat. Res., 263, 257-262... 

Warren, W, Clark, J.P, Gardner, E., Harris, G, Cooper, C.S. Lawley, PD. (1990) Chemical induction of thymomas in AKR mice interaction of chemical carcinogens and endogenous murine leukemia viruses. Comparison of W-methyl-A-nitrosourea and methyl methane-sulphonate. Mol. Carcinog., 3, 126-133... 

WHO (1993) Guidelines for Drinking Water Quality, 2nd Ed., Vol. 1, Recommendations, Geneva Wyrobek, A.J. Bruce, W.R. (1975) Chemical induction of sperm abnormalities in mice. Proc. 

B-74MI10502 J. C. Arcos and M. F. Argus Chemical Induction of Cancer , Academic Press,... 

Bone s data were not confirmed by Sadovnikov [6] who repeated his experiments. As for the assumptions of Haber and Polyakov concerning the role of electrons or chemical induction, it is noteworthy that they follow from the impossibility of explaining the data on the basis of a thermal reaction. We shall see later [7] that if the specific temperature conditions of the explosion are taken into consideration, the conception of a thermal reaction completely covers all the observed facts. 

On the other hand, and this is the most important consideration here, it has been shown above that no stoichiometrical relations exist between the quantity of fuel and the nitric oxide formed, and that the specific chemical nature of the fuel is of no account but only its heat of combustion it has been shown that the amount of nitric oxide formed is related to the oxygen content in the explosion products and not to the initial or average amount of oxygen during combustion. All this is rather difficult to reconcile with notions of chemical induction, the role of radiation, etc. and is a convincing argument in favor of the idea that the reaction of combustion is needed only to heat the mixture of 02 and N2 in which there then sets in a reversible thermal reaction (caused by the high temperature) ... 

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