Laboratory Methods of Inorganic Chemistry, 2nd English Ed. 1928

84 HALOGEN COMPOUNDS.

The reaction is extremely sensitive, and can be used as a test for

hydrogen peroxide as well as for titanium. A drop of ordinary 3%

hydrogen peroxide solution diluted with half a liter of water can

be detected by adding a few cubic centimeters of the reagent.

Molybdenum and vanadium compounds react similarly, though

less strongly, with hydrogen peroxide.

53. Anhydrous Titanium Trichloride.
    Titanium tetrachloride in aqueous solution may be reduced by metallic
    tin or zinc, or by electrolysis, to violet titanium trichloride; solutions of the
    latter have recently been recommended highly as reducing agents. The
    trichloride is obtained in an anhydrous condition by a method which is of
    quite general applicability. A mixture of titanium tetrachloride vapor and
    hydrogen is conducted through a red-hot tube whereby the trichloride deposits
    in the form of reddish-violet, non-volatile leaflets.

Place a tube made of difficultly fusible glass in a combustion,

furnace, and connect it, as shown in Fig. 17, on the one side with a

Combustion Furnace

FIG. 17.

100 c.c. retort, and on the other side with a receiver of twice that

size. Rest the receiver in a dish filled with ice, and add 40 to 50 g.
of titanium tetrachloride to the retort.

Fill the entire apparatus with hydrogen which is conducted

through the inlet tube of the retort. As soon as the gas escaping
at the other end is shown, on testing, to consist of pure hydrogen,

heat the combustion tube to bright redness and heat the tita-

nium tetrachloride nearly to the boiling-point by means of a small
flame, meanwhile passing a rapid stream of hydrogen continuously
through the apparatus. Regulate the temperature of the titanium

tetrachloride so that, as nearly as possible, all of it is decomposed

and none condenses unchanged in the receiver. If, however, this

is not accomplished, pour back the distillate into the retort and

repeat the process. Finally, disconnect the receiver (close the
end of the tube with a cork carrying a short delivery tube bent

downward) and heat the part of the tube projecting beyond the

furnace by fanning it with a flame, until no more white vapors