PAINTING MATERIALS
derivatives. In its resistance to hydrolysis and oxidation it is outstanding among
chlorinated hydrocarbons, and is among the most stable of this series (see G. O.
Curme Jr, ' Importance of Olefine Gases and Their Derivatives, III, Ethylene
Bichloride,' Chemical and Metallurgical Engineering, XXV [1921], pp. 999 ff.).
Being hard to ignite, it is used to lower the flash point of solvent mixtures. The
vapors are not dangerously toxic but are anaesthetic if breathed in high con-
centrations.
Ethylene Glycol (glycol [CH2OH-CH2OH]). This dihydric alcohol is an inter-
mediate between alcohol and glycerine (glycerol). The liquid is colorless, has a
sweet taste with no odor, and boils at I97.2°C. It will not mix with hydrocarbons
but will mix in all proportions with water, alcohol, and many organic liquids. It is
extremely hygroscopic, absorbing approximately twice its weight in water in an
atmosphere of room temperature, and 100 per cent relative humidity. This unfits
it for the common uses as a softener for mediums and dried films.
Ethylene Glycol Monobutyl Ether (butyl cellosolve [C4H9OCH2-CH2OH])
has the highest boiling point, I7O.6°C., and the lowest evaporation rate of the
common Glycol Ethers. The solvent action and other properties are similar to
those of cellosolve, but it is less volatile.
Ethylene Glycol Moaoethyl Ether (cellosolve [C^sOCHa-CH^H;]). This is
the most important of the glycol ether series, being a colorless, stable liquid, with
a mild, fruity odor. It is made synthetically from ethylene gas obtained in the
cracking of petroleum. The boiling point is I34.8°C. It is a good solvent for natural
and synthetic resins and is characterized by its moderate rate of evaporation (see
Glycol Ethers). It is used, in small percentages, in lacquers to improve flow quali-
ties and to prevent blush. •
Ethylene Glycol Monoethyl Ether Acetate (cellosolve acetate [C2HBOCH2-
CE^OOCCHa]). This clear liquid is a solvent for most natural and synthetic
resins and is miscible with most of the organic solvents. It is distinguished from
cellosolve, the closely related ethylene glycol monoethyl ether, by its higher
tolerance for petroleum hydrocarbons (see Glycol Ethers).
Ethylene Glycol Monomethyl Ether (methyl cellosolve [CH3OCH2-CH2OH]).
A member of the series of Glycol Ethers, this is miscible with water and with most
organic liquids. In many respects it is like the other members of the series, but
differs from the rest by being hygroscopic. It is a solvent for essential oils and for
natural and synthetic resins. Its boiling point is I24.5°C. and it is the most volatile
of the commercially available glycol ethers. As a solvent for certain dyes, it is
much used in the preparation of non-aqueous stains for wood and for vegetable
and animal fibres.
Gasoline (petrol). Produced chiefly as a motor fuel, this mixture of volatile,
aliphatic hydrocarbons is obtained from the distillation or cracking of petroleum.
Where rapid evaporation is desired, it is used as a solvent for paint mediums and