— 139 — 



camphene showed a depression of the melting point. It has not yet 

 been possible to carry out a further examination, owing to scarcity 

 of material. 



Reychler 1 ) gives some information on the addition of methyl 

 alcohol to camphene and trimethyl ethylene. If methyl alcohol 

 (about 4 mol.) is heated with methyl iodide (i mol.) for some hours 

 in a tube to about 120 to 140 , methyl ether is formed according 

 to the equation: 



CH 3 OH + CH 3 I = CH3OCH3 + HI; 



furthermore, methyl iodide is also formed back: 

 CH 3 OH + HI = H 2 + CH 3 I, 



until the system has absorbed a definite quantity of water. This reaction, 

 accomplished in the presence of 1- camphene, yielded, besides gaseous 

 methyl ether and a little unchanged terpene, chiefly inactive methyl 

 isobornyl ether (b. p. 190 to 194 ; d-^ 0,9235; n ye uow, lgo ^46643; 

 mol. refr. found 50,42, calculated 50,21). This shows that methyl 

 alcohol has been attached to camphene under the catalysing influence 

 of the hydrogen iodide, in accordance with the equations 



CH 3 OH + CH 3 I = CH 3 OCH 3 + HI, 



C 10 H 16 -)-HI = C t0 H 17 1 (in the status nascens) , 



C 10 H 17 I + CH 3 OH = C 10 H 17 OCH 3 + HI. 



This catalytic action of small quantities of acid has already been 

 known for a long time; for example, Bertram and Walbaum years ago 

 employed dilute sulphuric acid in order to attach acetic acid to camphene, 

 andSemmler as well as Hesse also knew the importance of this acid for 

 the formation of ethers from camphene. In an analogous manner 

 Reychler obtained from methyl alcohol, sulphuric acid, and trimethyl 

 ethylene, at 95 , the corresponding methyl amyl ether (5o°/o of the 

 theoretical yield), in which case hydrogen methyl sulphate must be 

 accepted as the catalyser. The addition or abstraction of water (in 

 forming tertiary amyl alcohol or terpin hydrate, in splitting up pulegone, 

 etc.), are reactions which must be attributed to the influence of the 

 acid. Whether Bertram's reaction and its modifications are analogous 

 to the hydration of trimethyl ethylene (conversion of a double into a single 

 bond) or that of trimethylene (ring-opening with formation of n-propyl 

 alcohol), cannot be determined in view of the present state of uncertainty 

 as to the structure of camphene. 



In the following pages, under fenchene, we refer to the formation 

 of higher fenchene homologues according to Grignard's reaction. Accord - 



x ) Bull. Soc. chim. Belgique 21 (1907), 71; according to a copy kindly sent us. 



