40 Proceedings of the Royal Irish Aoadeniy. 



present mucic acid as the dicarboxyl derivative of a radicle 

 C4H10O4 : — 



Ethyl-pyn-ol. 



(1) C4H80,2COO]S'(C2H5)H3 = CHiCCaH^)]^' + 2CO2 + NHsC^Hs 



+ 4H3O. 



Diethyl-carbo-pyrrol-amide. 



(2) CiH80,2COON(CoH5) H3 = C5H4 (C2H5),Ni,6 + CO.^ + SH^O. 



In order to explain the formation of the third product, CijHiglSrsOo, 

 we must assume that a molecule of ethylia, liberated according to 

 equation (1), enters into reaction with a molecule of unaltered 

 mucate, forming water and the new body : — 



(3) CiH8042COOIsT (C0H5) II3 + I^ (C0H5) Ho - C12H19N3O, + 6H0O. 



The quantity of this latter produced appears to increase with the 

 purity and dryness of the salt operated on, and the slowness with 

 which the distillation is conducted. The presence of even a small 

 quantity of di- or tri-ethylamine prevents its appearance altogether. 

 This is readily explained, since I have found that on heating a 

 mixture of ethyKum and dicthylium mucate, the base expelled in the 

 free state consists chiefly of diethylia, which evidently could not 

 enter into reaction (3). 



In fact, the yield of ethyl-pyrrol under these circumstances is 

 considerably greater than when the pure primary amine is employed. 



In the case of a double salt of primary and secondary ethyl- 

 ammonium, for example, the reaction appears to take place principally, 

 though not quantitatively, according to the following equation : — 



CHeO, {cooNraSS = C4H,(C,Il5)I^ + 2C0, + N(C,HOoH + 4H,0. 



Por the preparation of ethyl-pyrrol, then, the mixture of bases 

 furnished by digesting ethyl-iodide with ammonia, after removal of 

 the ammonia, may be used with advantage. 



The relations of the body C12II19N3O2 will be discussed further on. 



Distillation of Metliylammonium Mucate. 



This salt is also easily prepared by shaking up the requisite weight 

 of mucic acid with a somewhat dilute methylamine solution. The 

 mixture becomes warm, and if sufficient water is present the acid is 

 completely dissolved. On evaporation the mucate is obtained in an- 

 hydrous crystals. It is much less soluble than the corresponding 

 ethylia salt, and may, with little loss, be crystallized from boiling- 

 water. Even boiling alcohol scarcely dissolves it. 



Exposed to a temperature of 180°-190° C. in the apparatus pre- 

 viously described, it is decomposed with intumescence and evolution of 

 carbonic anhydride, and the production of a mixed aqueous and oily 



