﻿THE TEEPENE OILS OP MANILA ELEMI. 33 



in a freezing mixture with bromine in amyl alcohol and ether. Crystals began 

 to separate very quickly and after two or three hours they were filtered and 

 washed with a small amount of alcohol. Yield, 0.8 gram. When recrystallized 

 from alcohol the melting point was 118° to 121°. The latter was not altered 

 much by recrystallizing twice from a mixture of alcohol and acetic ester. The 

 final melting point was 118° to 120°. The prodiict was apparently a mixture 

 of dipentene and limonene tetrabromides. A sample of pure dipentene tetra- 

 bromide was then mixed with about 10 per cent of pure dextro-limonene 

 tetrabromide and the product, after being recrystallized once from a mixture 

 of alcohol and acetic ester, melted at 117° to 119°. This confirmed the previous 

 conclusion. 



As too great a proportion of dextro-limonene appeared to have been added 

 in the last experiment, it was repeated, using just about one-half the amount. 

 From 0.45 gram of the mixture there was obtained, after three hours, 0.65 gram 

 of dry crystals which, after having been recrystallized once from a mixture 

 of alcohol and acetic ester, melted at 124° to 125° and the substance was ac- 

 cordingly dipentene tetrabromide. 



Four grams of XVIII,A, purified, were mixed with 0.4 gram of dextro-limonene 

 and treated with bromine as before. After the product had stood over night, 

 0.2 gram of crystalline bromide was obtained, this being only about one-third 

 of the amount isolated in the previous case. After recrystallization from a 

 mixture of alcohol and acetic ester the body melted at 124° to 125° and was 

 accordingly pure dipentene tetrabromide. , 



Both V,A, purified, and XVI,A, purified, the former at least presumably con- 

 taining a very small proportion of Isevo-limonene, were treated with 15 per cent 

 of their weight of dextro-limonene and brominated in the usual manner. In 

 neither case had a trace of the crystalline product separated after twenty-four 

 hours but in each instance after two or three days, a small quantity of crystals 

 appeared which, after recrystallization, melted at about 124°. No great sig- 

 nificance is attached to this for ft was found that XVII,A, purified, when it 

 was brominated without the addition of limonene after standing for several 

 days yielded a very small amount of crystals which had about the same melting 

 point; the appearance of dipentene tetrabromide in these cases is possibly due 

 to tile continued action of hydrobromic acid upon limonene tetrabromide. 



(3) The two remaining samples of resin gave almost optically in- 

 active oils which were found to be terpinene and terpinolene. 



HIGH-BOILING OILS. 



The data obtained from the purified, high-boiling oils are placed in the 

 table below, in order to make plain the relations existing between them. 

 The boiling points at reduced pressures have already been given under 

 the different samples. These different boiling points were taken at some- 

 what different pressures, as it was not possible to obtain the same pressure 

 from day to day. However, the variation in pressure was not great and 

 it may be seen that the boiling points of the many different constant- 

 boiling products isolated were almost the same, the differences not being 

 over 2° or 3° when referred to a common pressure. These oils did not 



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