A Publication
of Reliable Methods
for the Preparation
of Organic Compounds
Annual Volume
Org. Synth. 1921, 1, 53
DOI: 10.15227/orgsyn.001.0053
Submitted by J. B. Conant and Neal Tuttle.
Checked by Roger Adams and H. C. N. Heckel.
1. Procedure
A 1-l. round-bottomed flask is fitted with a three-bulbed Glinsky fractionating column connected to a water-cooled condenser set for distillation. The crude diacetone alcohol (p. 199) which will usually weigh about 1100 g. (9.5 moles) and will have a specific gravity of about 0.91 is placed in the flask together with 0.1 g. of iodine. The mixture is now distilled steadily but not too rapidly (Note 1) with a small free flame, and three portions are collected as follows: I, 56–80°; II, 80–126°; III, 126–131° (Note 2). The first portion is acetone containing a small amount of mesityl oxide and water (Note 3). The second portion separates into two layers—water and crude mesityl oxide. The third portion is pure mesityl oxide.
While the third fraction is distilling, the aqueous layer in fraction II is separated in a separatory funnel and the crude mesityl oxide is dried with anhydrous calcium chloride and distilled through a Glinsky column; by this means a further amount of acetone and a small intermediate fraction (85-126°), which is best discarded, are separated. The pure mesityl oxide itself then distils between 126° and 130° and is added to the pure product already obtained as the third portion of the first distillation. The first complete distillation will require about five hours; the redistillation of portion III will take about one hour. The yield is 650 g. (65 per cent of the theoretical amount based on the total acetone employed) (Note 4). About 300 g. of acetone is recovered (Note 3).
2. Notes
1. The first distillation should not be interrupted but should be carried out at a slow uniform rate until complete.
2. The very last portion of fraction III is sometimes slightly colored, apparently by some iodine which comes over at the end of the distillation. A small amount of high-boiling residue is always left.
3. The acetone recovered from the preparation of mesityl oxide can be mixed with fresh acetone and used successfully in preparing more crude diacetone alcohol (p. 199).
4. If the crude diacetone alcohol contains less than 80 per cent of diacetone alcohol (when the refluxing is not carried out long enough, for example) the yield of mesityl oxide will be, of course, correspondingly low.
3. Discussion
There are two general methods for the preparation of mesityl oxide: the action of condensing agents (hydrochloric acid, etc.) on acetone, 1 and the dehydration of diacetone alcohol. 2 The action of acid condensing agents is very unsatisfactory; the yields are poor and considerable quantities of phorone and similar substances are invariably produced. The direct production of mesityl oxide from acetone and calcium oxide3 was tried, but without success; diacetone alcohol was the principal product. Several methods proposed for the dehydration of diacetone alcohol were investigated. That of Hibbert2 (using a very small quantity of iodine) is superior to the action of either concentrated sulfuric acid or aluminum phosphate.
This preparation is referenced from:

References and Notes
  1. Fitting, Ann. 110, 32 (1859); Heintz, Ann. 178, 343 (1875); Claisen, Ann. 180, 4 (1875); Freer and Lachmann, Am. Chem. J. 19, 887 (1897); Currie, J. Am. Chem. Soc. 35, 1061 (1913); Couturier and Meunier, Compt. rend. 140, 721 (1905); Mannich and Hâncu, Ber. 41, 574 (1908); Bodroux and Taboury, Bull. soc. chim. (4) 3, 829 (1908); Yllner, Svensk. Kem. Tids. 37, 227 (1925) [C. A. 20, 739 (1926)]; Gasopoulos, Ber. 59, 2188 (1926); Brederick, Lehmann, Schönfeld, and Fritsche, Ber. 72, 1417 (1939).
  2. Heintz, Ann. 178, 351 (1875); Kohn, Monatsh. 34, 779 (1913), Ger. pat. 208,635 [Frdl. 9, 62 (1908–10)]; Kyriakides, J. Am. Chem. Soc. 36, 534 (1914); Hibbert, ibid. 37, 1748 (1915); Hoffman, U. S. pat. 1,474,035 [C. A. 18, 401 (1924)]; Locquin, Ann. chim. (9) 19, 32 (1923).
  3. Hoffman, J. Am. Chem. Soc. 31, 722 (1909); Hertkorn, Ger. pat. 258,057 [Frdl. 11, 46 (1912–14)].

Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)

Diacetone alcohol

calcium chloride (10043-52-4)

sulfuric acid (7664-93-9)

hydrochloric acid (7647-01-0)

iodine (7553-56-2)

acetone (67-64-1)

Mesityl oxide (141-79-7)

calcium oxide

aluminum phosphate (7784-30-7)