1(56 RESEARCHES UPON THE CHEMICAL PROPERTIES OF GASES. 



In the oxidation experiments below cited, propylene from allyl iodide is under- 

 stood to have been used. 



JEx])t. 29. Palladmm Asbestos. — 



Propylene 3. 1 



Air 96.9 



Oxidation occurred : 



(1) At 170° (3) At 300° 



(2) " 180° (4) " 200° 



Expt. 30. Ruthenium jishestos. — The same mixture of propylene and air was 

 used. Oxidation occurred : 



(1) At 2350 - (3) At 2560 



(2) " 252° (4) " 2390 



Expt. 31. Rliodium Asbestos. — The same mixture of air and propylene. Oxi- 

 dation occurred : 



(1) At 283- (3) At 2T0O 



(2) " 284 ' (4) " 290O 



10. Trimbthtlene. — This very interesting hydrocarbon was obtained from tri- 

 methylene dibromide by the action of metalHc zinc (Gustavson, Be7\, 1887, p. 707, 

 R). 20 c.c. trimethylene dibromide with 60 c.c. of alcohol were poured over 60 gm. 

 of zinc dust. The reaction is as follows : 



J. / \ 



C = Hj + Za = CHj— CHj + ZnBrj. 

 CH,Br 



The trimethylene dibromide molecule, on losing bromine, assumes the form of a 

 ring and the resulting hydrocarbon is therefore a saturated compound. The gas is 

 evolved at a gentle heat (the temperature should not exceed 60°), and is purified by 

 ])assing through a condenser cooled by ice, by digestion with sulphuric acid and 

 finally by dilute permanganate of potash solution. It has been shown by Wagner 

 (Ber., 1888, p. 1230) that trimethylene prepared by the above reaction is liable to 

 contain propylene, which may be removed by prolonged contact with a weak solution 

 of permanganate of potash (which converts propylene into its corresponding glycol 

 but does not attack the trimethylene). 



JiJxp>t. 32. Palladium Asbestos. — 



Tvimetliylene 3. 1 



Air 96.9 



Oxidation occurred : 



(t) At 200 (2) At 290O (3) At 270° 



