Chemistry. — ''The Addition (\f Hydrogenbroinide to Allylhroin'ule" . 

 By Prof. A. F. Holleman and B. F. H. J. Matthes. 



(Communicated in the meeting of May 25, 1918). 



Ill the many cases that in my laboratory I had trinïethylene- 

 bromide prepared by the introduction of HBr gas into ailyl-bromide, 

 I was struck with the fact that now an almost quantitative yield 

 was obtained, now a much smaller yield, without our being able to 

 indicate the cause of this varying yield. When now my assistant, 

 Mr. DEN Hollander, had obtaijied almost exclusively trimethylene- 

 bromide in this addition in a very brightly lighted room, whereas 

 a few years ago Mr. Wuite observed by the side of it considerable 

 quantities of a product that boiled at a lowei' temperature (propylene 

 bromide) in the ordinary work-room, the supposition suggested itself 

 that daylight exerts an influence on this. Mr. Matthes undertook to 

 inquire more closely into this matter. 



For this purpose a quantity of allyl-bromide was divided into two 

 equal parts; one part was poured into an ordinary bottle, the other 

 in a bottle that had been perfectly blackened on the outside with 

 lacquer. The liquid in the ordinary bottle was exposed as much as 

 possible to the sunlight during and after the introduction of HBr. 

 Every time that no HBr was absorbed any more, it was closed, and 

 left to itself till the next day. After some days no further HBr was 

 absorbed. The blackened bottle was treated in the same way. The 

 absorption of HBr took place a great deal more slowly here, so that 

 the process had to be continued for some weeks, before comj)lete 

 saturation had been attained. 



When the contents of the two bottles was afterwards subjected to 

 distillation, the preparation from the ordinary bottle almost entirelj- 

 went over at constant temperature and at the boiling point of 

 triraethylene bromide. After distillation in vacuum its boiling point 

 amounted to 167°.l for 760 mm. 



The contents of the other bottle, on the other hand, presented a 

 very considerable boiling range, viz. from 100 — 190°. On fractionated 

 distillation a fraction of about 7 gr., going over between 140° — 150°, 

 was obtained, while between 155° and 165° a fraction of 22 gr. 

 went over. The former had about the specific gravity of propylene 



