SAPONIFIABLE OILS, FATS AND

191

bon dioxide into the beaker through a fine orifice of a glass tube to agitato
the liquid and hasten the washing. Boil for 30 minutes. At the end of thifl
time siphon out the water layer and repeat the treatment with water and
boiling until the water is no longer acid, as sr^own by a litmus test, Separate
the acetylated oil in a separatory funnel, filter in a drying oven or hot-water
funnel (Fig. 50, page 226) and dry.
Weigh accurately 2 to 4 gm of the acetylated oil into a flask and saponify
according to the method used in determining the saponification number,
measuring the alcohol solution of potassium hydroxide accurately and
running blank determinations for standardization. Evaporate thcMitoohol
and dissolve the soap in water. Add standard hydrochloric acid in H
quantity exactly equivalent to the potassium hydroxide added, warm ^ to
melt the fatty acids and filter through a wet paper. Wash with boiling
waiter until the washings are no longer acid, testing with. litmus paper by
barely touching a corner to the bottom of the funnel. The combined filtrate
and washings are titrated with tenth-normal base. Calculate the acetyl
value according to the definition of this number.
Maumene Number and Specific Temperature Reaction,—All
oils and fats react with concentrated sulphuric acid, heat being
evolved. The reactions are complex and cannot be exprcHHed
by a simple equation but oxidation occurs to a considerable
degree. The heat evolution varies with different oils arid it in, to
some extent, characteristic. The Maumen6 number in the
number of Centigrade degrees rise in temperature caused b'}/ mixing
10 cc of concentrated sulphuric acid with 50 gm of oil.
A small variation in the proportion of water in the acid cannon
a considerable variation in the heat evolved and to this extent the
figures recorded by different investigators are not comparable
because "concentrated sulphuric acid/' as obtained commer-
cially, is not a substance with any definite per cent of water.
In order partly to eliminate the errors due to variation in water
another determination may be made, using the same amount of
acid but substituting 50 gm of water for the oil. The ratio
Rise in temperature with oil
Rise in temperature with water
is known as the "specific temperature reaction." Thin number
is not subject to as great variation as is the Maumon6 number.
These determinations are necessarily very crude* and a con-
siderable variation may be expected, even under the, bent of
conditions. Variable radiation is one of the important Hources