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I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY
in an ice bath, except when methyl bromide gas was needed; then it was simply exposed t o the temperature of the room, whereupon the liquid boiled freely. Bubbling through the traps was continued until the trap containing the sample solvent attained constant weight. Correction was made for displacement of air by methyl bromide in the trap, absorption of methyl bromide by rubber policemen used to close the trap during weighings, and water vapor in the trap. In tests of mango juice it was also necessary to correct for measurable loss in lveight due to fermentation of the juice during the course of each test.
Vol. 43, No. 8
TABLE I. SOLUBILITY DATA Sample 1
2 3
Wt. of Water, G. 4.99 19.74 11.09
Vol. of Gas, PIl. 13.86 19.10 27.75
Correction for Change in Wt. of Gas, G. 0,0389 0.0537 0,0781
Increase in Wt. of Policeman, G. 0.0000 0.0019 0.0000
1 0
3
Correction for Vapor Pressure, MI. 0.42 0.57 0.83
Total Increase in Wt., G 0.3742 0.3197 0,2272
Increase in W t . of S o h . ,
of Methyl
G.
0.3353 0.2641 0.1491
Solubility
Bromide G./100 d. 1.341 1.341 1.342
EXPERIMEhTA L RESULTS
Results a t different temperatures were checked by using different amounts of solvent, so that corrections of different magnitudes were necessary. Methyl bromide weighs 0.0029 gram per ml. more than air at standard temperature and pressure. A typical set of data for 11 ater a t 25 O C. is given in Tahlc I.
TABLE 11. SOLUBILITY OF METHYL BROMIDE IN WATERA FRUIT JUICES Temp.,
Solvent TVater
Q
c.
10 :1 2.5 32
Pineapple juice
:= 6 m m .
Figure 1. Apparatus for Determining Solubility of Methyl Bromide in Water a i d Fruit Juices
The results a t this temperature, which approximates room temperature, were the most consistent. The solubility data for water and the various fruit juices are given in Table 11.
Mango juice Papaya juice
Correction In the article entitled “Vapor Phase Condensation of Aniline to Diphenylamine” by Hoelscher and Chamberlain [IND.ENG. CHEM.,42, 1568 (1950)], the authors wish to correct the equation relating the entropy of gaseous diphenylamine to temperature and the subsequent equation giving the variation of the entropy change of the reaction with temperature. Further study into the methods available for estimating the heat capacity-temperature relationship for gaseous diphenylamine, as well as the value of the entropy a t 298” I
