220 PROCEEDINGS OF THE AMERICAN ACADEMY 



furnishing an exception to the general rule of Beilstein that, in pres- 

 ence of iodine, bromine goes into the benzole ring even at high temper- 

 atures. The product of the reaction, if properly managed, solidified 

 on cooling, and was best purified by standing on paper, which sucked 

 out a quantity of black oil, and afterward by repeated crystallizations 

 from boiling alcohol with the assistance of bone-black. 



The composition of the paraiodbenzylbromide was determined by 

 the following analyses : — 



0.3721 gr. of substance yielded 0.3773 gr. CO, and 0.0773 gr. of H^O. 

 0.1774 gr. of substance gave, according to Carius, 0.1285 gr. of Ag. 

 0.1971 gr. of substance gave 0.2755 gr. of AgBr-|-AgI. There were 

 indications in this analysis that the oxidation had not been complete. 



Required for C^HglBr. Found. 



Carbon 28-28 " 27-66 



Hydi'ogen 2-03 2-31 



Iodine and Bromine 69-69 69-47 68-41 



100-00 99-44 



Properties. — Crystallized from alcohol, it forms flattened needles, 

 which usually have a straw yellow color, but can be obtained white by 

 repeated recrystallization with boneblack. It has an aromatic odor 

 and attacks the mucous membrane much less violently than any of 

 the other substances mentioned in this paper ; this, however, is very 

 probably due to the fact that it is not readily volatile at ordinary tem- 

 peratures ; it melts at 78|° ; does not distil with steam or only with 

 great difficulty ; sublimes in needles ; burns with a luminous green- 

 bordered flame ; and is insoluble in water, almost so in cold, much more 

 soluble in hot, alcohol, but slightly soluble in glacial acetic acid, freely 

 in ether, benzole, and carbonic disulphide. It is not easily attacked if 

 at all by an oxidizing mixture of potassic dichromate and dilute sul- 

 phuric acid. 



That all the substances mentioned in this paper contain bromine in 

 the side-chain is proved by the fact that, when boiled with alcoholic 

 sodic acetate, each one of them yields the corresponding substituted 

 beuzylacetate, from which the alcohol can be obtained by heating with 

 aqueous ammonia at 150° to \Q0°. The description of these com- 

 pounds, as well as of certain other derivatives of these substances, will 

 be found in the following articles of this series. For descriptions of 

 the parachlorbenzyl compounds the reader is referred to the papers 

 already cited in the introduction. 



