(52) 
Scuuurz searcely obtained any dichloro-oxyazobenzene when treating 
p-p-dichloro-azoxybenzene with fuming sulphuric acid, but p-p-dichloro- 
azobenzene was formed ; m-i-dichloro-azoxybenzene however yielded 
m-m-dichloro-oxyazobenzene in large quantity. 
Krier and  PrrscuKe ®) succeeded in almost entirely converting 
m-in-dinitro-azoxybenzene into m-im-dinitro-oxyazobenzene by heating 
the same with sulphuric acid at 140°. By heating 0-0-azoxytoluene 
with sulphuric acid at 100°—120° they could only obtain 0-0-az0- 
toluene accompanied by acids such as o-tolylazobenzoie acid. 
Limpricut') converted azoxytoluidine into oxvazotoluidine in an 
analogous manner, whilst ErBs and Scuwarz *) succeeded in converting 
p-p-diamino-0-0-azoxytoluene into p-p-diamino-o-o-oxyazotoluene by 
heating it with sulphuric acid at 100°—105°. 
My object now was to ascertain whether the above described intra- 
molecular rearrangement might be realised by other means than 
by the use of sulphuric acid. It was ascertained that the intramole- 
cular rearrangement of atoms in azoxybenzene is also possible by 
raising the temperature to at least 200° and by the influence of direct 
sunlight. In the first case a mixture is formed of p- with much 
o-oxyazobenzene ; in the second case only 0-oxyazobenzene is obtained. 
None of these changes is reversible. Also those derivatives of azoxy- 
benzene which undergo intramolecular rearrangement by the action 
of H,SO, are converted by the said agencies, but the action is slower 
and the amount is smaller than that obtained from azoxybenzene. The 
investigation of these derivatives has not yet been quite concluded. 
Acetic anhydride is without effect on azoxybenzene at the boiling 
temperature ; on heating however at 200° the change already takes 
place in a notable degree, much better than by merely heating the 
substance itself, while an acetate is either not formed at all, or only 
in very small quantity. P-oxyazobenzene is not formed at 200° but 
only the o-isomer. Solutions of azoxybenzene derivatives in acetic 
anhydride do not however suffer any intramolecular change at 200°, 
Addition of Zn Cl, or P,O, to acetic anhydride does not enable it 
to cause the change at the boiling point; heating with the so-called 
BECKMANN’S mixture is also without avail. By heating a solution of 
azoxybenzene in this mixture at 150° and 180° it appears that azoxy- 
benzene which, when prepared in the ordinary way is a yellow 
substance, is perfectly white when in a pure condition. The ordinary 
5) Ber. 17, 464 (1884). 
6) Ber. 18, 2552 (1885). 
1) Ber. 18, 1405 (1885). 
2) Journ. f. pr. chem. 1%1. 567 (1901). 
