60 DISTILLATION, DESTRUCTIVE 



2(CH s CaO<) - C'H'O 2 + 2(CaO,CO l ). 



Acetate of lime. Acetone. 

 C'H'CaO 1 = C 3 H fl O + CaCO 8 . 



If, however, the salt is not of a very low atomic weight, and the quanti; ' 

 on are at all considerable, secondary products are formed, as in the dry distillation <>t' 

 butyrato of lime, -when, if the substance is not in very small quantity, carbon is de- 

 posited, and a certain quantity of butyral, C 8 H 8 2 (C 4 H 8 O) is formed, and probably 

 other substances. 



As an illustration of the decomposition undergone when acids are distilled with a 

 great excess of dry base, we shall select that of benzoic acid, which under the circum- 

 stances alluded to yields benzole and carbonate of the base : 



C 14 H 6 4 = C 12 H 8 + 2 (CO 2 ) 



Benzoic acid. Benzole. 



C 7 H 8 2 = C 6 H 6 + CO 2 . 



5. Destructive distillation of bases. It has been found that the organic bases undergo 

 a much simpler and more direct decomposition when subjected to destructive distilla- 

 tion in presence of alkalis than when they are exposed to heat without admixture. 

 There are two bodies almost invariably found among the resulting products, namely, 

 ammonia and pyrrol. In this respect, therefore, the organic alkalis behave like 

 other nitrogenised animal and vegetable products. The decomposition is almost 

 always rather complex, and it is very rare that the products are sufficiently definite 

 to be arranged in the form of an equation. The most common substances found, are 

 the alcohol bases, and these are almost invariably of low atomic weight. One irivat 

 difficulty connected with researches- on this subject, is owing to the fact of its being 

 seldom that the products are in sufficient quantity to enable a thorough knowledge of 

 the molecular constitution to be arrived at. Unfortunately this information is much 

 wanted in consequence of the numerous cases of isomerism to be met with among the 

 alcohol bases. Thus it is difficult, when working in very small quantities, to dis- 

 tinguish between bimethylamine and ethylamine, both of which have the formula 

 OH 7 N (C 2 H 7 IT). See FORMULAE, CHEMICAL. 



It is remarkable that there is a great similarity between the products of the des- 

 tructive distillation of some of the most unlike nitrogenous substances. This is con- 

 spicuously seen in the case of bones, or rather the gelatinous tissues of bones, shale, 

 and coal naphthas, and cinchonine. An inspection of the following table, compiled 

 from a paper (by the writer of this article), ' On some of the Basic Constituents of 

 Coal Naphtha,' will render this evident : 



Gelatinous Tissues. Shale Naphtha. Coal Naphtha. Cinchonine. 



Pyrrol. Pyrrol. Pyrrol. Pyrrol. 



Pyridine. Pyridine. Pyridine. Pyridine. 



Picoline. Picoline. Picoline. Picoline. 



Lutidine. Lutidine. Lutidine. Lutidine. 



Collidine. Collidine. Collidine. Collidine. 



. . Parvoline. . . . 



Chinoline. Chinoline. 



. Lepidine. Lcpidinc. 



Cryptidine. 

 Aniline. . . Aniline. 



It is very possible that some of the above bases, having the same formula?, but de- 

 rived from different sources, will, in course of time, prove to be merely isomeri.-, 

 and not absolutely identical. The author of this article has found that the chino- 

 line of coal-tar is certainly not identical with that from cinchonine. Th.- bas.- from 

 the latter source yields a magnificent and fast blue dye upon silk, when treat 1 l.y 

 a process which gives no reaction if the coal-base be substituted. It is unfortunate 

 that the reaction is with the latter instead of the former, as it would have added one 

 more to the list of gorgeous dyeing materials yielded by coal-tar. 



6. General Remarks. The tendency of numerous researches, made during the last 

 few years, has been to show that there is no organic substance, capable of resisting 

 high temperatures, which may not bo found to exist amoug products of destructive 

 distillation. By varying the nature of the substance to bo distilled, and also the cir- 

 cumstances under which the operation is conducted, we can obtain an almost infinite 

 variety of products. Acids, bases, and neutral substances. sli<l, liquid, and iluid 

 hydrocarbons, organic positive, negative, and derived radicals, organo-metallic bodies 



