158 



Dr. K. J. P. Orton. 



[Dee. 1 



01 



3 : 5-Dwkloro-o-diozopherwl (3 : b-dichlm'o-O-diazoquinone), 



is 



CI 



contained in the yellow solutions which are obtained by any of the 

 methods just described. It is best prepared by adding excess of 

 sodium acetate to s-trichlorobenzenediazonium hydrogen sulphate or 

 nitrate. The mixture should be kept during 40 — 50 hours in the 

 dark ; — in the light the solution darkens, the diazophenol decomposing. 

 The liquid was then filtered from the amorphous yellow solid, made 

 strongly acid with nitric acid, and extracted four or five times with 

 ether. On evaporating the yellowish-brown extract, a mixture of 

 oil and crystals remained. In order to obtain the diazophenol, dry 

 hydrogen chloride was passed into the ethereal extract ■ this caused 

 the hydrochloride of the dichloro-o-diazophenol, 0!C,;HoClo:Xo,HCl, to 

 separate in small needles. This salt was converted into the diazo- 

 phenol by treatment with a small quantity of water. Thus prepared, 

 the diazophenol is an orange powder, which crystallises from an 

 ethereal solution in flattened orange prisms, which melt at 83 — 84°, 

 forming a red liquid : at 87° the latter decomposes. On analysis, 

 0-1068 gramme gave 0-1618 gramme AgCl. CI = 37'45. 



0*2004 gramme gave 25*4 c.c. of moist nitrogen at 14° and 766 mm. 

 N = 14-95. CeHgONsClo requires CI = 37-57 ; and N = 14-86 per 

 cent. 



This substance is very readily soluble in all solvents except petro- 

 leum; when dissolved in hot water it rapidly decomposes, the yellow 

 solution becoming brown and turbid. It dissolves in concentrated 

 solutions of acids, forming a nearly colourless liquid, which becomes 

 yellow on adding water. These acid solutions couple with alkaline 

 solutions of /2-naphthol. There is no doubt that this substance is an 

 ortho- and not a para-diazophenol, as j>diazophenols can be easily 

 recrystallised from hot water, whilst the ortho-compounds are decom- 

 posed by hot water. Again, ^-diazophenols are easily reduced to 

 7>aminophenols, but the ortho-derivatives are not reduced in a simple 

 manner.* 



The amorphous yellow substances which are formed in the cases 

 above described appear to be condensation products. The o-diazo- 

 phenol which is produced has the para- and one ortho-position 

 unoccupied, and being formed in the presence of a diazonium salt 

 and sodium acetate or bicarbonate, is under conditions which are very 

 favourable to the production of hydroxyazo-derivatives. A similar 

 yellow powder is precipitated when sodium bicarbonate is added to 

 a solution of the 3 : 5-dichloro-c-diazophenol. The yellow substances 



* Bolm.er, * Jouru. Pratt. Chem.,' 1881, [2], vol. 24, p. 460. 



