292 REPORTS ON THE STATE OF SCIENCE. 
for instance, 2C,;H,Br+Mg=MgBr,+C,H,.C,H;. Diphenyl is always 
formed in this manner in the preparation of magnesium phenyl bromide. 
With alkyl halides with low molecular weight this secondary reaction is 
not pronounced, but with halides of higher molecular weight it is difficult 
to work with calculated amounts owing to this reaction taking place to a 
marked extent. According to Grignard,! magnesium, allyl iodide, and 
ether give the compound C,;H;MglI,C3H,I, that is, all the metal is not 
attacked in the action. 
(4) Importance of completing solution of the magnesium.—It is not 
desirable to use a Grignard reagent containing an excess of the halide ; 
calculated amounts of magnesium and halide should be used and the 
solution of the magnesium completed so far as possible. It should be 
noted that action between magnesium alkyl halide and excess of 
alkyl halide can take place with formation of hydrocarbon, RMgBr 
+RBr=MgBr,.+R. R.? 
(5) Substitution of other solvents for ether.—It may be at once stated 
that ether is by far the most convenient solvent. 
Brihl* shows that bromocamphor, for example, when mixed with 
benzene or xylene dissolves magnesium at elevated temperatures. Anisole,* 
amyl ether,’ and toluene® have also been substituted for ethyl ether in 
certain reactions. ‘'schelinzeff? shows that, in the formation of Gri- 
gnard’s reagent, ether may be replaced by dimethylaniline. The reaction 
between dimethylaniline (2 mol.), ethyl iodide (1 mol.), and magnesium 
(1 atom) is assisted by the addition of a trace of iodine, but the mag- 
nesium does not dissolve so quickly as when ether is used. The method 
was used for the preparation of phenyl ethyl carbinol from benzaldehyde 
and of phenyl methyl ethyl carbinol from acetophenone. ‘That tertiary 
amines do actually combine with magnesium organic compounds was 
subsequently shown by F. and L. Sachs,* who obtained, for example, 
the compound C,H,N,C;,H;MgBr by the action of an ethereal solu- 
tion of magnesium phenyl bromide on quinoline. Tschelinzeff,? arguing 
that tertiary amines form compounds of the type RRRN. RX, has 
accordingly devised the following modification in the preparation of the 
Grignard reagent, where a tertiary amine acts as a catalyser. Inert 
solvents, like benzene, toluene, xylene, hexane, light petroleum, and 
various terpene hydrocarbons may be used in place of ether if a few 
drops of a tertiary amine are added. In the case of benzene the follow- 
ing procedure is adopted : The mixture of anhydrous benzene, halogen 
compound magnesium, and a drop or two of dimethylaniline is heated to 
boiling until the beginning of the reaction is indicated by the appearance 
of white flakes ; the reaction then proceeds without the application of 
external heat, and is finally completed by heating. The addition of a 
little iodine facilitates the starting of the action. In spite of the insolu- 
bility of the product, which separates as the type R. MgX, it is claimed 
that the action is much more energetic and often proceeds more quickly 
1 Ann. Chim. Phys., 1901, 24, 450; Houben, Ber., 1903, 36, 2897. 
2 Houben, Ber., 1903, 86, 3084. 
3 Tbhid., 1903, 86, 668, 4272; 1904, 37, 746; Malmeren, idid., 1903, 86, 2608. 
4 Malmeren,*idid., 1908, 86, 2619; Houben, idid., 1905, 38, 3019. 
5 Hibbert and Sudborough, Z7ans. Chem. Suc., 1904, 85, 933. 
® Bodroux, Compt. rend., 1904, 188, 700. 
7 Ber., 1904, 37, 2081. 8 Thid., 1904, 37, 3088. 
9 Tbid., 1904, 87, 4584; Chem. Zit., 1906, 30, 378. 
