While the original reaction mixture is standing, the temperature
gradually rises to 40'0 or 50'0 in the course of six to ten hours,
and then gradually cools off again. It is probable that at the end
of this time (when the flask has cooled again) the reaction mixture
could be distilled with nearly as good a yield as is obtained
after standing eighteen to twenty-four hours.

The wide variation in yields which are mentioned in the experimental
part is probably due to a slight change in the grade of the chemicals
which are used in this preparation. 3. Other Methods of Preparation

The cheapest and most convenient method by which mesitylene may
be prepared is by the action of a dehydrating agent upon acetone;
the agent most commonly used is sulfuric acid.[1] It has been shown
also that phosphoric acid will convert acetone to mesitylene.[2] A number
of other methods have also been used for the preparation of mesitylene:
the action of sulfuric acid on methyl acetylene;[3] the action
of sulfuric acid on mesityl oxide and phorone;[4] the action of
aluminium{sic(british)} chloride on methyl chloride and benzene;[5]
the action of mineral acids upon mesitoyl or benzoyl mesitylene;[6]
the action of phosphoric acid upon diaceto-mesitylene;[7] the treatment
of methylene-3-dimethyl-1, 5-cyclo-hexene-1 with bromine and then
with alcoholic potash.[8]

[1] Ann. 141, 131 (1867); 147, 43 (1868); 278, 210 (1893); Bud.
soc. chim. (2) 40, 267 (1883); J. prakt. Chem. (1) 15, 129
(1838); Am. Chem. J. 15, 256 (1893); 20, 807 (1898).

[2] J Chem. Soc. 99, 1251 (1911).