J 10 BACON. 



Portion soluble in ether. Portion insoluhle in ether. 



6.3 gram magnesium, 29 grams ben- 2.5 grams benzoin, melting point 1.36° to 



zaldehyde phenylhydrazone eorre- 1.37", 38 grams phenj-lhydrazone of 



spending to 15.0 grams benzaldehyde; benzaldeliyde corresponding to 20.5 



34 grams C,oH,s, boiling jKjint, 169° to grams benzaldehyde. 



173° ; specific gravity, 0.8220; N'^"-= 



D 

 1.4600. 11 grams higher boiling 

 oil from which there were separated 

 by means of ligroin 0.8 gram of a 

 halogen-free, crystalline solid. After 

 purification by several crystallizations 

 from petroleum ether, it melted at 

 137° and proved to be benzoin, by 

 melting it with that substance. 



The reaction between liydioplicUandi'ene magnesium bromide and Ijen- 

 zaldehyde thus corresponds exactl]' to the similar limonene reaction al- 

 ready studied in a j)revious paper.-* Several additional experiments 

 were performed with phellandrene hydrobromide and benzaldehyde under 

 varying conditions, but in every case dihydrophellandi'ene and benzal- 

 dehyde were the principal products of the reaction.-^ 



PHEI.I.ANnUENE IJIHYDROCH 1,0111 HE. 



Tlie dihydrochloride of phellandrene was also prepared. It does not crystallize 

 and is quite unstable, evolving hydrogen chloride at the ordinary temperature. 

 It does not react well with magnesium according to tlie Grignard reaction. 



THE FORMATION OF DIPEXTEXE. 



I have succeeded in converting a phellandrene into dipentene. 



The chloride of a phellandrene was heated for six hours on a reflux condenser 

 with an excess of alcoholic potash, and the product shaken out well with water, 

 dried with calcium chloride and distilled. The greater part of the terpene now 

 boiled at 178° to 180° and had no optical activity. This terpene was dissolved in 

 an equal volume of amyl alcohol and two volumes of ether, together with 0.7 

 volume of bromine, were added slowly on a freezing mixture. After several weeks 

 in the ice box, a large yield of crystalline dipentene tetrabromide, which after 

 crystallization from acetic ether melted at 124°, was obtained. The original a 

 phellandrene treated in the same manner and then inoculated with a crystal 

 of the tetrabromide showed the presence of no dipentene. 



-* hoc. cit. 



=° The majority of terpenes when treated with iodine are oxidized to p cymol. 

 Specimens of a and of /3 phellandrene were allowed to stand for two months with 

 an excess of iodine. They were then shaken out with alkalies, dried and distilled 

 and each gave a large yield of p cymol, with the following properties; Boiling 



point, 174° to 170°; specific gravitv. -^° =0.8489; n1''° = 1.4970. 



