V — 151 — 



Kunckel obtained the a-/?-dihalogen products from the «-halogen ketones 

 by reacting with phosphorus pentachloride after the following equation: 



QHsCOCHaCl + PClaCls^CeHsCCU-C^CH-POCl,; 

 C 6 H 5 CC1C1 • CH HC1 — HC1 = C 6 H 5 CC1 : CHC1. 



The hydrogen chloride was split off by distilling the trihalogen com- 

 pounds which were formed as an intermediary product. 



By the method above indicated the author obtained: propenyl benzene 

 (b. p. 167 to 170°), l-methyl-4-propenylbenzene, l-^sopropyl-4-propenyl- 

 benzene, l-methyl-4-?'sopropyl-3-propenylbenzene; also p-propenyl-o and 

 m-xylene and o-propenyl-^-xylene, as v/ell as a few derivatives of n-butenyl- 

 benzene, namely: l-methyl-4-butenylbenzene, 1,2- and l,3-dimethyl-4-n- 

 butenylbenzene, l-isopropyl-4-butenylbenzene and 3-butenylcymene. 



On the production of hydrocarbons from hydrazine compounds by 

 boiling with solid potassium hydroxide, see p. 165. 



Alcohols. 



Some time ago Sabatier and Senderens 1 ) reported on a simple method 

 for the identification of alcohols, based upon the catalytic reaction of 

 reduced copper at a temperature of 300° upon the vapours of the alcohols 

 in question. The body under examination is converted into an aldehyde, 

 a ketone, or a hydrocarbon, according to whether it is a primary, secondary, 

 or tertiary alcohol. G. B. Neave 2 ) has shown that the terpene alcohols 

 are attacked in a similar manner. He passed the vapours of d-borneol 

 ( a D2oo + 37,70°) over copper heated to 300°, with the result that he ob- 

 tained /-camphor (m. p. of the oxime 159 to 161°). Menthol gave rise to 

 menthone (m. p. of the semicarbazone 183 to 184°), terpineol and terpin 

 hydrate yielded dipentene (m. p. of the tetrabromide 122 to 124°), ^soborneol 

 a small proportion of camphene, together with a considerable proportion 

 of unattacked alcohol, and sobrerol (pinolhydrate), pinol. 



On a hydrocarbon obtained from linalool by heating with phenytiso- 

 cyanate, see p. 145. 



Menthol. According to a communication by J. B. Senderens 3 ), when 

 menthol is distilled with 1 or 2 p. c. concentrated sulphuric acid, it yields 

 menthene, b. p. 165 to 168°. Menthene is likewise formed by heating 

 menthol with 4 to 5 p. c. dilute sulphuric acid (1 : 2). From this it follows 

 that dehydration by dilute sulphuric acid is due to catalytic ation, and not 



x ) Bull. Soc. Chim. III. 33 (1905), 263. Report October 1905, 100. 



2 ) Journ. chem. Soc. 101 (1912), 513. 



3 ) Compt. rend. 151 (1912), 1170. 



