626 



REPORT — 1903. 



the hydrocarbon to carbon monoxide {e.g. mixtures of two volumes methane with 

 one volume oxj'gen, or of equal volumes of ethane and oxygen). 



The lowest temperature at which such mixtures of methane and oxygen 

 interact, when sealed up in a borosilicate glass bulb at atmospheric pressure, and 

 afterwards placed in a constant temperature air-bath, is somewhere about 300°; 

 in the case of the mixtures of ethane and oxygen it is about 22.5°. At all tem- 

 peratures ethane is oxidised much more rapidly than is methane, other conditions 



being equal. 



Under such conditions a portion of the hydrocarbon is burnt to, fanally, carbon 

 dioxide, carbon monoxide, and &ie&m, ioithmit any liberation of free hydrogen or 

 separation of carbon, wliile a portion of the original hydrocarbon always remains 



intact. ... 



Below are tabulated the analyses of the products from two typical experi- 

 ments : — 



Products from mixture CHj = 66-9, 

 maintained 7 days 



0, 

 at 



:33-l, 

 350°. 



14-0 



16-3 



0-9 



G8-8 



Products from mixture CjHr = 49"8, 

 0,, = 50'2, maintained 15 hours 

 at 250". 



CO, 

 CO 

 0, 

 CjHo 



15i) 

 41-2 

 nil 

 42-9 



nearly 32*0 



34-76 



CO 



CO . . • 

 O, . . . 

 CH, . 



Percent, contraction in \ 

 volume on opening i 

 cooled bulb under f 

 mercury 1 



We next devised an apparatus in wliich the reacting gaseous mixtures can be 

 continuously circulated day and night, at a practically uniform rate, (1) over a 

 surface maintained at a constant temperature ; and (2) through suitable washing 

 and coolino- arrangements for the removal of soluble or condensable intermediate 

 products. °A manometric arrangement enables us to talce pressure records pf the 

 gas in the apparatus at regular time-intervals throughout a given experiment, 

 which may often extend over many consecutive days and nights. The records so 

 obtained show, in the case of both methane and ethane, a regular and continuous 

 fall of pressure throughout the oxidation. 



The experiments with methane reveal the fact that formaldehyde plays an 

 important role as an intermediate product ; that, indeed, the oxidation involves at 

 least two distinct stages, namely : — 



1. A primary oxidation to formaldehyde and steam — 



H H 



H • C • H + : = II • C : + H,0 

 H 



2. The subsequent further rapid oxidation of the formaldehyde to carbon 

 monoxide, carbon dioxide, and steam. This may best be considered as the result 

 of two simultaneous reactions, namely : — 



H 

 (a) H- 6: + 0:0 = 0: C:0 + H,0 



II H 



{b) H-C:O + O:O + H-C:O = 20O + 2H,O. 



Possibly the latter may involve the formation and very rapid decomposition of 

 formic acid. Thus 



H H p H -. 



: 6 • II + : + II • C : - 2 1_0 : C • OH J = 200 + 2H,0. 



