A correlatiora is established betueen the efecaccelerated oxidution lest and their critical oxida-OUREU aiid Dufraisae of oxidation of tlie alcoliols (17) have reviewed tiveness gasoline inhittitors as measured by used as inhibitors. Dhar (6') their own extensive ~~~h~ : zr : work on antioxidants. Earlier reported by Seyewetz and Sisley potentials between 0.600 and 0.800 volt; fair dized." ( 2 0 . Progress to date in au-inhibitors are in the range 0.800 to 1.043 volts. Monreu and Dufraisse (171, toxidation has been summa-compoun& ?,,ilh the lathr figare while assuming oxidation of the rized The by power Milas of (24). preventing ac-have practically no inhibiting action under the ~~~~~~ ::''I tion of free oxygen on sensitiveconditions Of test. ffydroquinone and cerlain tion and write, "One recovers niaterial is possessed largely by ethers show less i7hibiting action in the bomb the three bodies (oxidizable subsubstances which are them-kat than their potentials would lead one to stances, inhibitor, and oxygen) selves readily oxidized. This th,is is attributed to their tendency to in t.heir original state." Their mechanism, however, has been severely criticized by Milas (14) was by undergo direct oxidation. and Dufraisse (17) and pointed out earlier b y M i t t r a and and Perrin ($0). Dhar (16) who stated, "it seems possible that the pheuommon The chain theory of reaction meclianism is useful in of negative catalysis is possible only nhen the catalyst is explaining inliibitor action. The hypothesis of so-called liable to be oxidized." In contradiction, Milas (14) reports chains of reacting molecules was crystallized in 1924 by inhibition of oxidation of anethole by benzoqninone and Christiansen ( 3 ) . He stated that in a bimolecular reaction, anthraquinone, which, be st,ates, "are far from being easily unless it is immeasurably fast., only a fraction of the pairs oxidized." Of import in this connection is inhihition hy of molecules which collide are able to react. Those reacting l,%naphthoquinone, which was reported by Mat.ill (13) and are activated molecules w!iose energy exceeds a certain value. in Part I of this paper (7). Fieser (9) su~gcsts that tlie Just after reaction, "the molecules of the reaction products mechanisni of inliibition by this substance is addition of possess an available energy great.ly in exccss of t,be mean water to form a trili3.droxynaphthalene, an oxidizable subenergy at the temperature considered. Now, these very st,ance wlriclr is the actual inhibitor. Such an addition was 'liot' molecules have sufficient energy to activate molecules shown by Fieser and Peters (IO) to be the first step in the of the rcactants at the first encounter, and when these react, decomposition of 1,2-naplithoquinone, which is urLst.able in the resultants in their turn again are able to act as activators, solution.and so on. Consequently, it is possible that the occurrence During the period in which it protects a substance from of one elementary reaction mill give rise t,o a whole series of oxidation, an inhihi...
