Theoretical organic chemistry / by Julius B. Cohen.

  • Julius B. Cohen
Date:
1902
Catalogue details

Licence: Public Domain Mark

Credit: Theoretical organic chemistry / by Julius B. Cohen. Source: Wellcome Collection.

    31/604 (page 11)
    In the second fractionation (Table II.) each of the first distillates is redistilled and collected within a narrower range of tempera¬ ture. Thus, the first fraction (A) is distilled until the thermometer registers 790. Fraction B is then added, and the distillate divided into two fractions, 79°-8r and 8i°-85°. Fraction C is added, and so forth. The new fractions, C and E', are again fractionated. Ultimately, two fractions are obtained; B'consisting of nearly pure benzene, and F' of nearly pure toluene. TABLE II. 1 j A' below O 79 B' 0 O 0 79 -81 C' 8i°-85° D' 85°-io5° E' io5°-io8° F' io8°-iior Residue | A. Added B. . . „ C. . . „ D, E . » F. . . ” • , * RefractionatedC' E' . 5 c c. 42 C.C. 12 C.C. (10 c.c.*) (9 c.c A) 7 c.c. 50 c.c. _ (ii c.c.*) 6 c.c. 22 C.C. 5 c.c. 42 c.c. 5 c.c. 54 c.c. 7 c.c. 50 c.c. 6 c.c. 27 C.C. 42 c.c. Expt. i.—Distil a mixture of 20 c.c. of alcohol, b. p. 78°, and 50 c.c. of water, b.p. ioo°. The mixture will not inflame. Collect the first 10 c.c. of the distillate. The liquid now contains such a large proportion of al¬ cohol that it readily takes fire. If the fractional dis¬ tillation has to be con¬ ducted in vacuo it is undesirable to inter¬ rupt the boiling in order to remove the Fig. 5.—Receiver for fractional distillation under reduced pressure.