176 Proceedings of the Royal Irish Academy. 



XXIX. — On the Distillation Pkoditcts of the Sacchaeates of 

 AjirMONnjM AND EiHYLATvtMONniM. By Edwin Lappek, F.C.S.^ 

 L.C.P.I., and Chichester A. Bell, M. B., Univ. Dublin. 



[Eead, June 24, 1878.] 



In a former communication/ one of us has shown how that by the 

 action of heat upon the mucates of the fatty amines, a series of bodies 

 is produced which may be regarded as substitution compounds of the 

 base pyrrol, CiHgiS', obtained by the dry distillation of ammonium 

 mucate. Amongst these is a dicarboxyl derivative of ethyl-pyrrol, 

 CiIl2]S"(C2ll5) (CO 011)2, the formation of which is of peculiar interest, 

 since it shows that the production of the pyrrol nucleus from mucic 

 acid is not dependent on the separation of its carboxyl groups. 



In the hope of being able to throw some light upon the isomerism 

 of mucic and saccharic acids, we have now studied the action of heat 

 on the saccharates of ammonium and ethylammonium. It appeared to 

 us very probable that by this action we would obtain either bodies 

 isomeric with those from mucic acid, or totally different products ; 

 and that, in either case, we might be able to draw conclusions as to 

 the constitution of the two acids. In one respect our expectations have 

 not been fulfilled : nevertheless, our experiments have established an 

 interesting difference in the deportment of the two acids, which may 

 at some future time be of importance in determining their constitution. 



Ammonium saccharate was prepared exactly according to the 

 directions given by Liebig. The acid was purified by crystallization 

 of its acid ammonium salt, which was then converted into the neutral 

 salt. 



The saccharate is most conveniently heated in a capacious glass 

 retort, by means of a paraffin bath. Decomposition begins when the 

 bath is heated to 136° C, and takes place quickly at 160° C. After 

 some time the whole of the saccharate disappears, leaving only a 

 slight carbonaceous residue in the retort. Ammonia and carbonic 

 anhydride escape in large quantity, and the liquid in the receiver 

 consists of an aqueous solution of ammonium carbonate, covered by a 

 layer of oily liquid. The neck of the retort is covered with numerous 

 crystals, but these consist entirely of ammonium carbonate. On care- 

 ful evaporation on the water bath, the watery distillate leaves only a 

 trace of non-volatile matter. The oily layer, after being washed, 

 dried, and rectified, possesses all the characters, boiling-point, specific 

 gravity and reactions, of ordinary pyrrol, its identity with which is 

 thus satisfactorily proved. The following equation expresses the 

 reaction — 



C6HioOs(NH3)2 = C4H5JS" + 2CO2 + KE3 + 4H2O. 

 1 "Proceedings," Second Series, vol. iii., Science, p. 33. 



