— 167 — 



Table II. Heating in pressure-bottles. 



Mixture consisting of 



Period 



of 

 Heating 



d20O 



[0CJD20O 



% Ester] Temperature 



1 vol. pinene + 1 vol. J 

 glacial acetic acid . . \ 



8 hours 

 24 „ 



0,9465 

 0,9502 



+ 4° 25' 

 + 3° 40' 



5,80 100° 

 8,37 100° 



1 vol. pinene + 2 vols. 1 

 glacial acetic acid . . \ 



1 8 hours 



24 „ 



0,9807 

 0,9838 



+ 2° 33' 



+ 2°36' 



8,58 

 13,12 



100° 

 100° 



1 vol. pinene + 1 vol. J 

 glacial acetic acid. . \ 



8 hours 

 24 „ 



0,9590 

 0,9568 



-f-4°24 f 

 + 3° 52' 



18,78 140—150° 

 18,90 ; 140—150° 



1 vol. pinene + 2 vols. ( 

 glacial acetic acid . . \ 



8 hours 

 24 „ 



0,9962 

 0,9881 





r 2°35' 

 -1°30' 



25,50 | 140-150° 

 25,40 140—150° 



1 vol. pinene + 1 vol. ( 

 glacial acetic acid. . [ 



8 hours 

 24 „ 



0,9517 

 0,9581 



+ 3°0' 

 + 3°18' 



11,5 ! 175—185° 

 19,1 175—185° 



1 vol. pinene + 2 vol. ( 

 glacial acetic acid . . \ 



8 hours 

 24 „ 



0,9895 

 0,9876 



+ 2°37' 

 + 1°23' 



11,5 



25,3 



175—185° 

 175—185° 



Heatin. 



1 vol. pinene + 1 vol. 

 glacial acetic acid . . 



g with a 



15 min. 

 1 hour 

 20 „ 



reflux- 



condenser. 



1,37 

 1,99 

 ! 4,82 

 | 19,61 | 



— 



1 vol. pinene + 2 vols. 1 

 glacial acetic acid . . 



15 min. 

 1 hour 

 20 „ 



— 



- | 2,39 j 

 7,46 ! 

 8,75 j 

 ! 24,80 



— 



Sievers prepared a set of mixtures of pinene with equal and with double 

 quantities by volume of glacial acetic acid, and a corresponding set of 

 limonene mixtures. In some of the latter he introduced into the solution 

 a known weight of hydrogen chloride. Finally, Sievers made experiments 

 with limonene with an equal and a double volume of glacial acetic acid 

 with the addition of a known weight of sodium acetate. The density, 

 rotation, and ester value of these mixtures were repeatedly determined 

 within a period of from 7 to 9 months, and again after 2 1 /* years. 

 Part of the figures ascertained by Sievers are reproduced in table (I) 

 |>. 166) below. 



The figures in the above table show that by adding sodium acetate 

 pinene and limonene are more ready to combine with acetic acid than 

 is the case when adding hydrochloric acid. 



The pinene was heated with glacial acetic acid in pressure-bottles 

 at high temperatures and the ester of these mixtures was determined. 



