390 



NAPHTHA, CAOUTCHOUC 



owing to the presence of some unknown neutral nitrogenous bodies. When a slip of 

 deal "wood is moistened with hydrochloric acid and held over a vessel of crude bone 

 oil, it rapidly acquires a deep crimson tint. This is in consequence of the presence of 

 the extraordinary basic substance pyrrol. The latter, when in a crude state, possesses 

 a most disgusting smell, so much so, that the offensiveness of bone oil was at one time 

 mainly attributed to its presence. It has, however, been discovered that pyrrol 

 when perfectly pure has a most fragrant and delightful perfume, somewhat recalling 

 that of chloroform, but still more pleasing. 



The basic portion of bone oil may be extracted by shaking it up with moderately 

 strong oil of vitriol. This must be done with precaution, as large quantities of gases 

 are evolved, consisting of carbonic acid, hydrosulphuric and hydrocyanic acids. The 

 fluid when permitted to repose separates into two layers, the upper being the purified 

 oil, and the lower the acid solution of the bases. The latter being separated is to bo 

 distilled until about one-third has passed over. This distillate will contain the chief 

 portion of the pyrrol. The head of the still is then to be removed and the fluid 

 boiled for some time to remove the last trace. The acid solution, after filtration 

 through charcoal, is to be supersaturated with lime and distilled. The distillate 

 contains the whole of the bases. The apparatus should be so arranged that those 

 bases which are excessively volatile, and consequently come over as gases, may be 

 received in hydrochloric acid. The hydrochloric solution and the oily bases are to be 

 examined separately. The former is to be evaporated carefully to the crystallising 

 point, and then allowed to cool. By this means the ammonia may be removed by 

 crystallisation as chloride of ammonium. 



When no more sal-ammoniac can be obtained by crystallisation, the mother-liquid 

 is to be treated with potash, in an apparatus so arranged that any gaseous products 

 evolved may be collected in hydrochloric acid. The retort must have a thermometer 

 in the tubulature to enable the temperature to be properly regulated. All the bases 

 distilling below 212, are to be received in hydrochloric acid, and their presence 

 demonstrated by converting them into platinum salts, and fractionally crystallising. 

 The bases distilling above 212, are to be separated by fractional distillation. An 

 examination of the hydrochloric solution will, according to Dr. Anderson, demonstrate 

 the presence of methylamine, ethylamine, propylamine, butylamine, and amylamiue. 

 The following table contains the names and physical properties of the bases which are 

 contained in that portion of the basic oil which distils above 212. The amylamine, 

 and even the propylamine, can be separated from the basic oils, by fractional distilla- 

 tion, instead of the fractional crystallisation of platinum salts, but the latter involves 

 less labour. 



Table of the Physical Properties of the Pyridinc Series of Bases, 



Bone oil will not become very valuable as a naphtha for general purposes until 

 some cheap method of removing its odour has been discovered. The Oleum animals 

 Dipellii of the older chemists and pharmaceutists was prepared by distilling bones ; it 

 was very similar in properties to bone oil. C. Of. W. 



NAPHTHA, CAOUTCHOUC. Syn. Caoutchoucine ; Caoutchine. Caoutchouc, 

 by destructive distillation, yields several hydrocarbons, the accounts of which are 

 contradictory. By repeated rectifications they may be separated into fluids of 

 steady boiling-points. The late Dr. Gregory succeeded in obtaining a fluid hydro- 

 carbon from caoutchouc which distilled at 96, but when treated with sulphuric ;ifi<l. 

 and the fluid separated by means of water, another hydrocarbon was obtained boiling 

 at 428. It is most probable, however, that the true composition of caoutchoucine 

 has not yet been made out. This will appear by consulting the analyses yet made, 

 many of them indicating too low a hydrogen for the OH" series, and more 

 nearly approximating to n (C*H 4 ). It is quite plain, however, that caoutchine is, 

 in every sense of the term, a naphtha. Caoutchine is one of the best solvents known 

 for india-rubber. C. G. W. Sec CAOUTCHOUC, 



