210 PROCEEDINGS OF THE AMERICAN ACADEMY 



other temperatures as those in the per cents are if our present results 

 are accepted. 



We had hoped, in beginning this research, to make a careful com- 

 parison of the action of bromine on toluol and its substitution products, 

 but the differences between the results from different substances fall 

 so near the wide limits of error of our process, that we prefer to con- 

 fine ourselves to . the following very general statements. Bromine is 

 taken up by toluol more rapidly than by any of its substitution pro- 

 ducts studied ; orthobromtoluol seems to take up bromine less rapidly 

 than parabromtoluol, and this inference from our quantitative results 

 is confirmed by our experience in the preparation of the substituted 

 benzylbromides in large quantity, when it has been observed invariably 

 that the parabromtoluol absorbed bromine most rapidily, the meta- 

 compound less so, and the orthobromtoluol even more slowly than the 

 meta. In regard to the percentages of benzylbromide formed from 

 each substance we do not feel that our results allow us to make any 

 generalization, as the apparently lower numbers obtained from the 

 orthobromtoluol may be due to differences in working up the product, 

 which in the case of the ortho-compound is a liquid, while the para- 

 bromtoluol yields a pasty solid. 



"We have also tried some experiments with toluol at lower tempera- 

 tures, and found that at 58°, and even at 0°, a small amount of benzyl- 

 bromide was formed, as shown by obtaining an amine on treatment of 

 the product with alcoholic ammonia. The rate at which the bromine 

 was taken up was, however, extremely slow, and we feel that these 

 experiments need confirmation. 



Effect of the Addition of Iodine. 



We were induced to take up this branch of the subject by the obser- 

 vation that paraiodbenzylbromide was formed by the action of bro- 

 mine on paraiod toluol, even when the flask was filled with violet vapors 

 of iodine during the addition of the bromine, which contradicted Beil- 

 stein's Law as generally understood ; but we have not studied it so 

 thoroughly as the effect of differences in temperature, as we could find 

 no sufficiently satisfactory and easy method of determining the amount 

 of benzylbromide formed. 



Our best series of results (Table V.) was obtained from parachlor- 

 toluol bromired at 160°, the crystals of parachlorbenzylbromide formed 

 being weighed after they had been brought to the melting-point of the 

 pure substance, 48°.5. 



