296 REPORTS ON THE STATE OF SCIENCE. 
is adduced in support of this view. Again, Ahrens and Stapler | formulate 
the compound obtained from ethylene dibromide thus :— 
C,H Br 
2 So 
C,H; Mg . CH, . CH,Br 
The theoretical aspect of the Grignard reaction has been specially 
studied by Tschelinzeff. In an early paper ” he concludes that the ether 
in the preparation of the Grignard reagent in the usual manner plays the 
part of a catalyser. He found that interaction between magnesium and 
alkyl halides took place in benzene solution only when the mixture was 
heated strongly. In the presence of a little ether (or of anisole), however, 
the reaction took place at a much lower temperature, at which no action 
occurred when the ether (or anisole) was absent ; the action was very 
slow, requiring from one to two days for its completion. The white mass, 
which separated contained no ether, exhibited all the ordinary reactions 
of magnesium organic compounds, and was formed in considerable yield. 
The point is that this effect was produced by means of a small amount of 
ether. 
Reference has already been made in Section II. to Tschelinzeff’s use of 
tertiary amines as catalytic agents. In a subsequent communication,* 
Tschelinzeft describes thermochemical experiments, in which the heat 
evolved by the action of ether on the ether-free compounds obtained by 
this catalytic method was measured ; 
C,H, C,H, Meh 
2 "Noe 2 Ge 5 
+ ‘ + T 
One. Ce eT 
RMglI 
The formula of Baeyer and Villiger is preferred to 
C,H MgX 
Sod (Grignard) 
C,H, NR 
or to the representation from Werner's standpoint 
GH, 
Osi MgR)X' 
O,4,7 ; 
Although ether is not readily eliminated from the complex 
it is possible to study the heat etfect produced by the change 
C,H, MgR 
(C,H,),0+RMgX= So 
OH \x 
since it is possible to prepare the ‘individual ’ magnesium compounds free 
from ether. Tschelinzeff concludes that in the preparation of the 
Grignard reagent by the ordinary method there are two distinct reactions : 
1 Ber., 1905, 38, 3259. 2 Ibid., 1904, 87, 4534. 2 Thid., 1905, 38, 3664. 
* Annalen, 1902, 8322, 261. The theory of the Grignard reagent is also discussed 
by Abegg, Ber., 1905, 38, 4112. 
