96 
IOWA ACADEMY OF SCIENCES. 
showed that Lesimple (Ann. 159, 192), had made dipheni- 
lene oxide instead of diphenyl oxide. 
Up to the present time diphenyl ether and its derivatives 
have been prepared by at least thirteen different methods, 
and have been studied by no less than twenty-five different 
chemists, among whom were Fittig and Kekule. While 
the methods are various, the yield in almost every case is 
remarkably small. The leading methods that have been 
used are as follows: 
W. Hoffmeister (Ber. 8, 747) prepared diphenyl ether by 
warming diazo benzine sulphate and phenol, but the yield 
was very small. Hirsch (Ber. 28, 870) used the chloride 
instead of the sulphate and modified the method in some 
other respects and obtained a yield of 50 per cent of the 
aniline used. 
Merz and Weith (Ber. 14, 187) obtained a small yield by 
heating phenol with zinc chloride, and also with aluminum 
trichloride. 
Gladstone and Tribe (Jr. Chem. Soc., 41, 5 and ditto 49, 
27) made various methyl phenyl ethers by distilling the 
corresponding aluminum cresolates. 
Willgerodt (Ber. 12, 1278) obtained a large yield of the 
trinitro derivatives by heating pikryl chloride with one 
molecular equivalent of potassium hydroxide. 
One of the most productive methods that has been used 
is that originated by Haeussermann and Teichmann (Ber. 
29, 1446), and also independently by F. Ullmann (Ber. 29, 
1878). The heated potassium phenolate and several of its 
derivatives with the various nitro halogen derivatives of 
benzine and obtained, as a rule, a good yield. 
Experimental Part: — In approaching the study of 
diphenyl ether derivatives, it was suggested by Dr. H. W. 
Hilly er of the University of Wisconsin, that the method 
of Haeussermann and Teichmann might be extended to 
the Cresols, and in the following account it will be seen 
that this was accomplished with a good degree of success. 
It has seemed best to adopt the nomenclature of Haeus- 
sermann and Bauer (Ber. 29, 2083) as the simplest, and at 
the same time susceptible of very extended application. 
