PHILIPPINE TERPENES AND ESSENTIAL OILS, III. 107 



LIMONENE HYDKOEROMIDE AND ACKTALDEHVDE. 



Limonene hydrobromide with the following properties, boiling- point at 10 

 millimeters, 106° to 109°, specific gravity, 5iL =1.1211; N 1^=1.5012; bromine 



found, 36.1 ; calculated, 36.4 per cent. Fifty grams of this hydrobromide were 

 subjected to the Grignard reaction with 10 grams of magnesium. After the 

 reaction was complete, 15 grams of acetaldehyde were slowly distilled into the 

 mixture. There is marked heating and a yellowish, sticky solid separates. From 

 this solid, using the usual method of treatment, there were obtained 27.0 grams 

 of CioHis (calculated, 31.3 grams), boiling point, 173° to 175° at 760 millimeters, 



specific gravity, §2^ =0.8256 ; N — = 1.4583. The residual oil, 3.5 grams, contained 

 4° D 



a trace of halogen, had no hydroxyl groups, and was probably a diterpene. Ace- 

 taldehyde, therefore, reacts on hydrolimonene magnesiimi bromide just as does 

 benzaldehyde. 



It is very interesting to note that hydrolimonene magnesium bromide is, when 

 first formed, a liquid insoluble in ether. After lying under the ether for a few 

 days it changes into a crystalline solid insoluble in ether. 



LIMONENE DIHYDEOBROMIDE AND BENZALDEHYDE. 



One hundred grams of limonene from orange-peel were mixed with an equal 

 volume of absolute ether and saturated with dry hydrogen bromide, 150 grams of 

 crystalline dihydrobromide melting at 64° (from ether) resulted." A mixture of 

 150 grams of limonene dihydrobromide and 150 grams of benzaldehyde was slowly 

 added to 35 grams magnesium, which had been rendered active, in 400 cubic 

 centimeters of ether. A fairly vigorous reaction took place. The reaction mixture 

 was decomposed with ice and dilute sulphuric acid, the oils were poured into 

 petroleum ether, and 14 grams of a crystalline solid separated. This was recrys- 

 ■tallized several times from benzol. It is moderately soluble in hot benzol, insoluble 

 in the cold, almost insoluble, hot or cold, in ether, petroleum ether, ligroin, acetic 

 ester, methyl or ethyl alcohol, acetone, or carbon bisulphide. TTie melting point 

 is not sharp. At 195° the compound begins to darken and at about 212° it melts 

 with marked decomposition. The compound used in the following analysis liad 

 been recrystallized 15 times from benzol and consisted of beautiful, white crystals 

 ■which under the microscope seemed to be homogenous. 



0.2000 gram substance gave 0.2181 gram AgBr. 



0.2000 gram substance gave 0.2180 gram AgBr. 



0.2340 gram substance gave 0.4365 gram CO, and 0.0590 gram H:;0. 



0.2730 gram substance gave 0.5100 gram CO, and 0.0700 gram H^O. 



0.5 gram dissolved in 27 grams benzol raised the boiling point 0°.065. 



Calculated 



for C,oH2oBr4 



(per cent). 



C 51.40 



Calculated 

 Cor,H2(iBr4 

 (percent). 



50.58 



Found 

 (percent). 



50.93 



Found 

 (per cent). 



50.90 



H 2.85 



2.90 



2.80 



2.84 



Br 45.70 



46.49 



46.40 



46.40 



Molecular weiaht 700.00 



690.00 



745.00 





" The dihydrolialide always results no matter how thoroughly dried the solvent 

 bas been, when hydi'ogen halides are run, to saturation, into limonene dissolved 

 in ether, while with petroleum ether, only the mono compound is obtained. 



