it still would not affect seriously our conclusions in view of the experiment (described above) on benzylmagnesium chloride, F-chlorotoluene and carbon dioxide. The tests with the several benzoic acids are sufficiently important to warrant further study, and we are collecting samples of benzoic acid which (as well as we can determine) are free of any hereditary and acquired taint of halogen.Benzylmagnesium Chloride and Cupric Chloride.-From the reaction carried out in the customary manner14 between 0.3 mole of benzylmagnesium chloride and 0.3 mole of cupric chloride there was obtained a 70% yield of pure dibenzyl and a trace of di-ptolyl. The 4.6 g. of non-steam distillable tar gave only benzoic acid on oxidation.Benzylmagnesium Chloride and Azobenzene.-From one mole of benzylmagnesium chloride and 0.44 mole of azobenzene there was obtained 52.3% of benzidine and 37% of dibenzyl.Benzylmagnesium Chloride and Formaldehyde.-Formaldehyde was led over the surface of 0.4 mole of benzylmagnesium chloride until a negative color test21 was obtained showing that all of the Grignard reagent had been used up. In addition to a 26.9% yield of o-tolylcarbinol there was obtained about 0.3 g. of di-F-tolyl.

A series of 2-thiazolylazo dyes for cellulose acetate was prepared. Substituents in the 4-position have little effect on the color of 2-thiazolylazo dyes. The color of the dyes containing various groups in the 5-position deepens in the order of increasing negativity of the substituent. Thus, dyes containing the nitro group in the 5-thiazolyl position are blue to greenish blue; these dyes have superior dyeing and fastness properties. The bathochromism of the 2-thiazolylazo dyes is illustrated by comparison of the blue dyes from 2-amino-5-nitrothiazole with dyes from the benzene analog, p-nitroaniline; dyes from the latter are red.The bathochromism of the 2-thiazolylazo dyes is discussed in terms of the influence of the 2-thiazolylazo structure and of substitution on the coupler and diazonium constituents.The preparation and properties of new 2-aminothiazole intermediates are described. Certain problems encountered in nitration and oxidation reactions are discussed.

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The rate of anaerobic bleaching of red ferric thioglycolate in mixed thioglycolate (0.2 Af)-acetate (0.1 Af)-phosphate (Af/15) buffers pH 4.6-5.S at 37°( system I) has been measured spectrophotometrically and shown to follow second-order kinetics, whereas the anaerobic bleaching of the labile blue ferric thioglycolate in 0.07 M thioglycolic acid in 60% ethanol at -35°follows first-order kinetics. In the air saturated system I the rate of oxidation, catalyzed by 1.4 X 10 ~5 M iron salt, was measured, as well as the steady-state concentration of red ferric thioglycolate. The oxidation rate was maximal at pH 4.9. The iron catalysis of thioglycolate (RSH~) oxidation by oxygen has sometimes been assumed to proceed as follows:(a) formation of ferrous complex, Fe(II)RS-complex, (b) oxidation: Fe(II)RS-complex + Os -Fe(III)RS-complex, and (c) autoóxidation-reduction: Fe(III)RS-complex -*• Fe(II)RS-complex + RSSR . It is shown that the oxidation rate calculated for this scheme can account for only 1-3% of the experimentally observed oxidation rate. A modification of this reaction scheme involving free radicals is discussed.

YIELDS OE GRIGNARD REAGENTS. II 1583 an excellent yield of benzylmagnesium chloride (see following paper);whereas if allyl bromide is added at once to magnesium in ether, very little allylmagnegium bromide results, and most of the allyl bromide couples to form diallyl. However, by the special conditions described recently by Gilman and McGlumphy12 it is possible to obtain allylmagnesium bromide in greater than 90% yields. The Naphthylmagnesium Bromides.-The yield of a-naphthylmagnesium bromide reported earlier215 is incorrect. This was very probably due to the sparing solubility of this Grignard reagent in ether (see footnote h to Table I). The comparatively high yield of /3-naphthylmagnesium bromide is both interesting and valuable in view of the discouragingly low yields of this RMgBr compound reported by others.13