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NITRO DERIVATIVES OF PHENOL 489

In Table 114 partition coefficient of picric acid between two liquid phases arc

tabulated for water-toluene and water-ether (Sisley [44]).

TABLE 114

PARTITION COEFFICIENTS OF PICRIC ACID BETWEEN TWO LIQUID PHASES

Concentration of

picric acid g/l.

of the solution

Solution volumes

water-toluene

Grammes of picric acid in 100 ml

of the solution

water toluene

Partition

coefficient

10g 100 : 100 0.275

(^3) 0.125
(^1) 0.062
0.1 0.010
1
0.1
0.01

• water-ether
  10g 106 : 96

water

0.374 -

0.085

0.0105

0.000952

0.725 1 : 2.63

0.175 1 : 1.24

0.038 1 : 0.63

• 
  
  
  
  • ether
    0.670
    0.011
    0.00011
  
  
  
  


• 
  


• 
  

  1 : 1.79
  1 : 0.129
  1 : 0.010

  
  


• 
  

Similar values have been obtained by Sisley for amyl alcohol and water.

Mindowicz [45] has also studied the partition coefficient (k) of picric acid between

water and various organic solvents. Table 115 summarizes his results expressed in

terms of the Nemst [46] and Shilov [47] equation

where n is an exponent independent on the temperature, Cl and C 2 are concentrations.

TABLE 115

Benzene-

Temperature water Temperature

°C N = 1.727 °C

kx10^2

10 1.563 20

30 1.892^40

50 2.275^60

70 2.673^80

Toluene- Chlorobenzene-

water water

n = 1.667 n = 1.674

k x 10^2 kx10^2

1.875 2.421

2.323 2.965

2.884 3.548

3.532 4.416

AS may be seen from the above data, from concentrated solutions picric acid

can be extracted by an organic solvent, while in the case of dilute solutions it remains

in the aqueous phase.
Hygroscopicity. Picric acid is only slightly hygroscopic. Marsh [48] found that

picric acid, in contact with water-saturated air at 32°C for 48 hr absorbed 0.37%

of water. If, however, the picric acid contained 0.05% of SO 3 , as sulphates or