CHAPAMAXAND THOIZI’ ON THE RELATION III.-The Reladioiz between the Products of Oxidabion and the Molecular Constitution of the Bodies Oxidized. By E. T. CHAPMAN and W. THORP. [Contribution from the Laboratory of the London Institution.] PART XI. GLYCERIN and mamxlite :-these two substances resemble each other in many particulars. They both yield iodides of secondary alcohol-radicals when treated with hydriodic acid. These iodides in both instances yield olefines when acted upon by alcoholic solution of potash. By oxidation these olefines yield acids of lower carbon-condensation than themselves. That obtained from mannite P-hexylene yields as we have already shewn propionic acetic and carbonic acids. The olefine from glycerin has been shewn by M.Truchot to yield acetic and formic acids ; we have oxidized it and obtained acetic and carbonic acids. It is well known that glycerin when heated with caustic potash yields acetic and formic acids. We have examined the reaction and can confirm this statement. These acids have the same carbon-condensation as those obtained from the corresponding olefine by oxidation. Mannite when treated mi th caustic potash yields propionic acetic and formic acids. The following experiments enable us to confirm this result. Thirty grammes of mannite were heated with caustic potash just moistened with water. The mixture melted turned yellow frothed up very much and gave off inflammable gas; the contents of the dish were theu dissolved in water and distilled with excess of sul-phuric acid.Formic acid was found in the distillate. A portion of the latter was converted into haryta-salt. Per centage of Bn from mixed salts 52.83. The remainder of the distillate was neutralized with potash evaporated to dryness and gently warmed I3ETWEEN THE PRODUCTS OF OXIL>.\TIOS ETC. with concentrated sulphuric acid. Carbonic oxide was evolved.* The mixture was then diluted and distilled and a portion of the distillate was converted into haryta-salts. Per cent. of Ba 50.11 showing the presence of acetic acid because the formic acid was destroyed and no other acid yields a barium-salt containing more than 48.41 per cent. of barium. q!he remainder of the distillate mas neutralized with standard solution of caustic potash and divided into four fractions the first three of one-fifth each and the last of two-fifths.These different fractions were as usual converted into baryta-saSts and the percentages of barium they contained were determined. 1 Theoretical Acid to which this Substance taken. Ba-SO4 Per cent. 1 found. Bs found. per cent. corresponds. i ~-First fraction 6 3962 -3249 Propionic Second fraction *3690 -3042 99 Third fraction 3 *4120 *3-140 Fourth fraction 5 -5382 -4902 53-55 Acetic Practions 1 and 2 correspond closely enough with propiouic acid. Fraction 3 corresponds to propionic acid contaminated with a trace of some lower acid acetic of course; and fraction 4 corre-sponds to pure acetic acid. Thus mannite also yields to this treatment acids corresponding with those obtained by the oxida-tion of the olefine obtained from itself.We now proceeded to oxidize glycerin and mannite with our ordinary oxidizing mixture bichromate of potash and sulphuric acid. In both instances a most violent reactioii occurs; carbonic acid is evolved abundantly and formic acid produced. No other acid appears to be fwmed. The absence of other acids was proved by our ordinary process of fractionation and by the fact that on converting a portion of the distillate in both instances into baryta-salts and determining the percentage of barium the numbers obtained agreed with those required by formic acid. The results of these two experiments the treatment with caustic potash ThiB treatment with concentrated sulphuric acid does not injure any acid of the acetic series from acetic to caproic inclusive.32 CHAPMAN AND THORPE 03 THE RELATION ETC and the process of direct oxidation appear to be to a certain extent antagonistic. The latter process would lead one to believe that these two substances contain each atom of their carbon directly attached to hydroxyl and hydrogen. We observed that mannite in acid solution decolorized perman- ganate of potash. It appeared therefore of interest to determine how much permanganate a given weight of mannite would de- colorize. But as formic acid would probably be among the pro- ducts of the action we previously experimented on some formic acid and found that perrnanganate can exist in the presence of formic acid for some hours without decomposition provided the fluid hq strongly acid with sulphuric acid.In neutral or alkaline solu- tions the permanganate is rapidly decolorized. If therefore formic acid be once produced it would not be at once decomposed by the further action of permanganic acid. Having ascertained the behaviour of formic acid we proceeded to operate upon a sample of mannite in precisely the manner ordinarily employed in determining oxalic acid. At first the solution decolorized somewhat slowly exactly as in the case of oxalic acid; then the process rapidly quickened and for some time the decolorization of the permanganate took place almost instantaneously ; afterwards longer and longer periods were re- quired for the decolorization.When after ten minutes' standing the colour had not perceptibly decreased the process was stopped. 0*36*of mannite dissolved in dilute sulphuric acid decolorized 214 c.c. of permanganate of potash. 100 c. c. of the perman- ganate solution contained 0.094504 of available oxygen therefore the mannite had required 0.20372 of oxygen. This corresponds to 92 per cent. of the amount of oxygen required to produce for-mic acid. As there was so much difficulty in marking the completion of the reaction and as the perrnanganate solution qas much more rapidly decomposed when concentrated than when dilute we devised a modification of the experiment. More than sufficient permanganate of potash was introduced into a flask along with dilute sulphuric acid and a weighed quantity of maiinite added.After ten miirutes oxalic acid was added in more than sufficient quantity to decolorize the excess of permanganate employed. Then the excess of oxalic acid was in its turn determined by per-* 1-08of msnnite was dissolved in 150 c. c. of water and + of the solution em-ployed in each experiment. IIARTLEY ON CRLORSULPITIDB OF ClARI3ON. msngmate. The result of this roundabout experiment ras that a little more oxygen was employed than would have been required if the whole of the mannite had been converted into formic acid. 0.36 of mannite dissolved in dilute sulphuric acid mas treated with 300 C.C. of the above-mentioned permanganate solution. It was allowed to stand ten minutes.A known excess of oxalic acid was then added which immediately caused the fluid to become colourless and clear. The amount of odic acid in the fluid was then determined by the addition of permanganate. It appeared that 238 c. c. of permanganate had been required by the rnannite. Another such experiment was made with the exception that the liquid mas allowed to stand fifteen minutes before the addition of oxalic acid instead of ten. In this case 241 c. c. of permanganate were required by the mannite. From the first experiment it appears that 102.26 per cent. of the amount of oxygen required to convert mannite into formic acid was actually consumed in the operation. In the second ex- periment in which the action had been allowed to continue half as long again 103.6 per cent.of the required amount of oxygen mas actually consumed. These differences between the numbers found and those calcu-lated are very trifling and are amply accounted for by the slow action of permanganate upon formic acid. In order that no doubt whatever might rest upon the subject the formic acid was actually distilled out of the mixture remaining after these opera- tions. From it were obtained the well-known actions of formic acid. A portion of it was converted into a baryta-salt and the percentage of barium determined. 0.3402of the salt yielded 0.3468 of sulphate of baryta; there- fore 59-93per cent. of barium. Theoretical percentage 60.30. Therefore mannite is decomposed by nascent oxygen thus :v C,H,,06 + 70 = 6CH,O + H20.