CHEMICAL AND PHYSICAL PAPERS. 69 



M 



A NEW DERIVATIVE OF DIAZO-AMIDOBENZENE. 



(2, 2' dibrom, 4, i' dimethyl diazo amido-benzene.) 



By Edward Baetow and H. C. Allen, University of Kansas, Lawrence. 



Read before the Academy, at Topeka, December 31, 1904. 



m -BROMTOLUENE may be prepared from jt;-acettoluid by bromi- 



nation, elimination of the acetyl group, and submitting the 

 amine thus formed to the Griess reaction/ thus replacing the araido 

 group with hydrogen. 



In following out the Griess reaction forthediazotizing of m-brom- 

 jO-toluidine by means of nitrous acid, we obtained well-defined bright 

 yellow, needle-like crystals. Wroblevsky,'- who prepared m-bromtoluene 

 by the above-mentioned series of reactions, warms the alcoholic solu- 

 tion after diazotizing to effect reduction and makes no mention of an 

 intermediate product. Sellards^ mentions a crystal broth which is 

 formed before the reduction takes place. 



Our method of procedure was as* follows : /^-acettoluid was sus- 

 pended in water and brominayed according to Wroblevsky'-' by adding 

 bromine with occasional shaking, but without particular care to cool 

 the reaction mixture. Under these circumstances ?«-brom-/)-acettoluid 

 is formed. 



The acetyl group, which serves to protect the amine, is then re- 

 moved by saponifying with either NaOH or KOH. Wroblevsky^ 

 claims that only KOH will act, while Grete^ and Sellards^ find that 

 NaOH does equally well. Our experience was that either would re- 

 act, but that the NaOH required longer heating, and also heating on the 

 sand-bath. The wi-brom-^-toluidine was then distilled with steam, 

 dried with calcium chloride and diazotized by leading nitrous acid into 

 a solution in absolute alcohol. The nitrous acid is best prepared by 

 using arsenic trioxide having a specific gravity of 1.3 to 1.35. The ni- 

 trous acid was conducted through a reflux condenser, cooled by ice- 

 water, and a Woulff 's flask, surrounded by a freezing mixture, into the 

 alcoholic solution. The condenser and flask serve as traps for nitric 

 acid as well as for cooling the nitrous acid. The gas was absorbed 

 until near the end of the reaction, and at the same time the bright 

 yellow crystals mentioned above were formed. 



If any acid is present in the alcoholic solution, the substance 

 formed will be reduced to m-bromtoluene. Ten drops of sulfuric 

 acid in ten grams of the substance completely reduced it in thirty 

 minutes. When no acids are present, however, the crystals are very 



1. A, 121-258. 2. A, 168-154. 3. Dissertation, U. of K., 1904. 4. A, 177-232. 



