Absolute Alcohol (see Alcohol).
Acetone (dimethyl ketone [CH3COCH33). As the most important member of
the ketone group of solvents, this has been known since the early XIX century.
Formerly it was obtained to a large extent from the dry distillation of calcium
acetate which, in its turn, was a by-product of wood distillation. Now acetone
comes as a by-product from the fermentation of molasses or corn mash in the pro-
duction of n-Butyl Alcohol and is also made synthetically. The liquid is clear and
boils at 56.i°C. The odor is strong and rather sweet. Acetone is completely miscible
with water and with most organic liquids. Industrially, it is perhaps the most
generally used of the low-boiling solvents because of its solvent strength and its
low cost. It dissolves cellulose nitrate, other cellulose derivatives, synthetic resins
of the glyceryl phthalate, thio-urea, and vinyl types, the natural soft resins, and
certain waxes. Fossil resins dissolve in it to a large extent, and shellac to more than
80 per cent. It is miscible in all proportions with linseed, tung, and polymerized
oils.
Since acetone is miscible with water, oils, and most solvents, it makes a good
coupling agent for combining immiscible fluids. It is an important ingredient of
neutral paint removers because of its action on resins and on linoxyn (oxidized
linseed oil). Used in excess with lacquer and varnish films, it may cause them to
blush, especially in humid weather; this is from condensation of moisture within
the film when rapid evaporation of solvent cools the surface. Acetone is only
mildly toxic and is safe to use in well ventilated places, though its vapors are
highly flammable. (See L. C. Cooley, ' Acetone,' Industrial and Engineering
Chemistry,, XXIX [1937], pp. 1399-1407.)
Alcohol (Cologne spirits, grain alcohol, ethyl alcohol, ethanol j^HsOEQ).
The second in the series of monohydric alcohols is inexpensive when obtainable
tax-free, yet is the purest and probably the most useful of the organic solvents.
It acts readily on almost all natural resins, including shellac, and on many of the
synthetic compounds that serve as film materials in painting, but it is compara-
tively inactive on the drying oils and quite inactive on waxes and aqueous
mediums. The liquid is clear and volatile, boiling at 78.3°C.; vapor pressure at
2o°C. is 44 mm. Alcohol is miscible in all proportions with water and with most
organic liquids and is a solvent for some inorganic substances like sodium
hydroxide.
The preparation of alcoholic beverages by fermentation from grains and fruits
can be traced to ancient times. A. Lucas {Ancient Egyptian Materials and Indus-
tries [London: Edward Arnold and Co., 1934!, p. 23) says that although the
ancient Egyptians made beer and wine, they were not acquainted with the
process of distillation and had no distilled spirits. According to him, also, it is
the general belief that distilled spirits were not known until the Middle Ages,
the first use of them being for the preparation of medicine. E. O. von Lippmann
(JBeitrage zur GesMchte der Naturwissenschajten und der Technik [Berlin: Julius
185