Contributions towards the history of caproic and œnanthylic acids / by J.S. Brazier and G. Grossleth.

  • Brazier, James S. (James Smith)
Date:
[1851?]
Catalogue details

Licence: Public Domain Mark

Credit: Contributions towards the history of caproic and œnanthylic acids / by J.S. Brazier and G. Grossleth. Source: Wellcome Collection.

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    which appeared to increase in some measure with the temperature at which the distillation was performed. Caproate of baryta, when sud¬ denly exposed to a rapidly rising temperature, disengages this gas in considerable quantities, only a small portion of oily products being formed, which are moreover very dark and resinous, whilst the dis¬ tillate obtained by moderate temperatures is nearly colourless. The carbonate of baryta which remains in the retort is nearly black from separated carbon. These facts, as well as the observations made by Chancel and Guckelberger* in the analogous decomposition of butyric, valeric, and caprylic acids, left no doubt that the liquid product was a mixture of various substances. When dried over chloride of calcium and subjected to distillation, it commenced boiling at 120° C. (248° F.), the boiling-point rising gradually to 170° C. (338° F.). Between 160° and 170° the largest quantity was collected. This portion, on recti¬ fication, showed a pretty constant boiling-point at 165° C. (329° F.). With the lower portions, no constant boiling-temperature could be observed. Several combustions made with this product, exhibited in¬ variably a deficiency of carbon when compared with the percentage of carbon required by the formula of caprone, Cn Hn 0. This, as well as the results of Chancel, who actually separated butyrale, or at all events a substance of similar composition from the product of dis¬ tillation of butyrate of lime, lead us to believe that a small quantity of caprale, C12 tl12 02, may be formed in this process. This assumption is supported by the deportment of the lower dis¬ tillate, from which ammonia removes a small portion of matter. The ammoniacal solution, after having been exposed to the air for some time, yields with acids oily globules having the characteristics of caproicacid. Unfortunately, we had not enough material to elabo¬ rate this question any further. We were, however, benefitted by the observation, inasmuch as it induced us to submit the chief fraction boiling at about 165°, previously to analysis, to an additional distilla¬ tion over hydrate of potassa. After this treatment, it showed a con¬ stant-boiling point at 165° C. (329° F.). When burnt with protoxide of copper, this liquid gave the following results : I. II. 0*1641 grms. of substance gave: 04655 0*1949 0-2263 0-6423 0-2668 » „ carbonic acid, and „ water. „ substance gave : „ carbonic acid, and „ water.