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

TITANIUM TETRACHLORIDE. 83

is essential to maintain a strong, steady stream of chlorine, the

bubbles of which pass through the wash bottle so rapidly that it

is just impossible to count them. Titanium tetrachloride collects

in the receiver in the form of a liquid which is colored yellow by

free chlorine and is clouded by small crystals of ferric chloride.

1

The operation requires about three hours. The amount of rutile

prescribed is sufficient to yield enough material for two fillings of

a combustion tube.

Filter the crude product through a dry Gooch crucible contain-

ing an asbestos-felt, and then allow it to remain in contact with

mercury, or copper filings, in a thick-walled bottle closed with a

cork stopper; occasionally shake it vigorously, adding a little fresh

metal each time, until, at the end of about twelve hours, all the

free chlorine has combined. A little sodium amalgam may be

added toward the end of the process in order to remove traces

of vanadium. After again filtering through a Gooch crucible,

distil the clear liquid from a fractionating flask with a side-arm

condenser (Fig. 7, p. 6). Boiling-point, 136° to 137°. The liquid

has a strong refracting power for light, and it fumes in the air.

Yield, 100 to 130 g. Dependent preparations: Titanium Disul-

phide, No. 58; Potassium Titanium Fluoride, No. 103.

Titanium Dioxide from Titanium Tetrachloride. Pour about

10 c.c. of titanium tetrachloride, a little at a time, into 200 c.c. of

water, whereby hydrolysis takes place, although the hydrated

titanium oxide which is formed remains in colloidal solution.

Add a little sulphuric acid, and boil; titanic acid is thereby

precipitated in a form which can be readily filtered. Wash the

precipitate with water containing ammonium nitrate, dry it in

the hot doset, and ignite it in a porcelain crucible until white

titanium dioxide is left. In order to remove the last traces of

sulphuric acid, which are retained very persistently, ignite the

product several times with ammonium carbonate. Yield, almost

theoretical.

Hydrogen Peroxide Reaction. Fuse a little titanium dioxide

with potassium acid sulphate, and dissolve the melt in cold water.

A few drops of this solution when treated with an aqueous solution

of hydrogen peroxide show a brownish-yellow to yellow color.

(^1) If the rutile used has a high iron content, it can happen that the tube
will become clogged with crystals of ferric chloride.