MIXTURES OF HYDROCIILORIC ACID AND METHYLETIIER 



J. P. KUENEN. 



In 1875 FiUEDEL ') discovered that methylether (B. P. — 23°.5 C.) 

 aud hydrochloric acid when brouglit together below zéro produce a 

 liquid whicli boils at 2° C. ; this liquid was uot a chemical coinpomid 

 iu the usual sensé: tlie proportion in whicli tlie two substances are pré- 

 sent in the liquid was not always the same and moreover did not corres- 

 pond to a simple molecular composition (about 6 parts of ether against 

 5 parts of acid). At the same time the formation of liquid at tempéra- 

 tures far above the boiliiig-point of llie ether and the stroiig contrac- 

 tion of the vapour- mixture above the boiliiig point whicli he observed 

 proved that the two substances display a sti'oug mutual affinity. lie 

 therefore coucluded that the molécules of the acid and the ether unité 

 to form a dissociable molecular compound : thèse double molécules occur 

 both in the vapour — hence the abnormally high vapour-density, — 

 and especially in the liquid. The latter is a mixture of double-molecules 

 and single molécules of the components. 



From Eriiouel's observations it foUows that mixtures of the sub- 

 stances in question hâve the comparatively rare peculiarityof a maximum 

 in their boiling-points and tliei'cfore a minimum in (lieir vapourpressu- 

 res. The object of the investigation described in this paper was to trace 

 this minimum up to the critical région and to obtain a complète pres- 

 sure-temj)erature diagram for thèse mixtures. The theory of mixtures 

 developed by van dek Waalh ") makes it very probable that jnixtures 



') Compt. Rend. 81 p. 152. 



') KuENEN. Phil. Mag. Ai p. 199. 



