( G50 ) 



(C,Hj,J(ll = c:, H,C1 + C,11,J 

 is a bimoleciiUii' one. 



Since the cliloride is conipamble willi a salt such as KCl, it may 

 be concluded tliat the transformation does not occur in the non- 

 dissociated molecules but between the ions. This idea would agree 

 with that propounded by Wai.kkr and Hamhly ^} for the transtbruiation 

 of ammonium isocyanate in aqueous or alcoholic solution into urea, 

 a reaction which also appeared to be a bimolecular oue. Walkek 

 and Hambly were enabled to support their view by showing that 

 either ammonium- or isocyanic acid ions cause a i-etarding intluence 

 on the reaction investigated by them as both diminish the dissociation 

 of ammoinum isocyanate. lu our case a similar beha\i()ur of chlorine 

 and iodonium atoms does not present itself. Hydrochloric acid has 

 certainly a retarding intluence but this is too large to be explained 

 by a diminution of the ionisatioii. Then again, iodoinum hydroxide 

 has a strong accelerating power. Via nnist, therefore, thiidv here of 

 a special catalyzing ijifluence of hydrogeu- and hydroxyl ions: 

 apparently the lirst acts here as a i-etarding catalyzer, an iidluence 

 of which up to the present but few ijistances are known. Then, if 

 the acid is neutralised (compare expmt. IVj, the ti-ansformalion proceeds 

 in a regular manner whilst the chlorine ion is still j)reseut in about 

 the same concentration. 



The most prol)ablc view of the mechainsm of the transforuiation 

 of the iodonium haloids is therefore that the reaction takes place 

 between two molecules. 



A trace of iodine retards the transformation in an inci'easing degree. 



This investigation will be continued later on. 



Oiynnic. clwni. Lahonftoi'ij, UnlrersUij of Aindcfdaiu. 



Chemistry. — "^ Xiirdtiaii of si/inntc/f/ciil di/i/'fi-oinuso/." I>y Dr. J. J. 

 lii,ANKs.MA. (Communicated by Prof. C A. Loüry ur. IhuYN). 



(Comnumicaled in the inceling of March 28, 11)03). 



In a previous communication "j it has been stated that pentanitro- 

 phenol is readily formed by the action of nitric acid on symnielrical 

 dinitrophenol whilst symmetrical dinitroanisol is attacked w ilh diflicnlty 

 by nitric acid. It seemed, ho\N'e\cr, not inipossiiile that synnuclrical 

 dinitroanisol might slill l»r further nilralcd and this indeed appeared 



1) J. Ch. Soc. 67. 74(i (1895). 



'-) Proc. Royal Acad, io Jan. 1902. 



