90 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. 3, 747) prepared diphenyl ether by 

 warming diazo benzine sulphate and phenol, but the yield 

 was very small. Hirsch (Ber. 23, 370) 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, 127S) 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, 

 1S78). 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 Pakt: — In approaching the study of 

 diphenyl ether derivatives, it was suggested by Dr. H. W. 

 Hillyer 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. 



