Twelve grams of concentrated sulfuric acid is added to 180 g. (167 cc., 1.8 moles) of acetic anhydride in a 600-cc. beaker, after which 60 g. (0.55 mole) of quinone (Note 1) is added gradually in small portions with constant mechanical stirring. The temperature rises and should be held at 40–50° during the addition of the quinone. A temperature higher than 50° leads to decomposition of the product whereas a temperature lower than 40° causes a much slower reaction. Good temperature control can be obtained by using care in adding the quinone and by the use of a cooling bath and efficient stirring. The reaction goes smoothly and does not evolve an excessive amount of heat.

After all the quinone has been added, the solution is allowed to stand. It should be watched closely at first to see that the temperature does not rise above 50°, but at the same time it is well not to cool it below 40°. When the mixture starts to cool of its own accord, a precipitate begins to form. As soon as the mixture has cooled to about 25° (Note 2), it is poured into 750 cc. of cold water, whereupon a white precipitate separates. The mixture is cooled to about 10° and filtered with suction. The product is recrystallized from 250 cc. of 95 per cent ethyl alcohol and dried. The drying is best done in a vacuum desiccator, through which a very small stream of air is allowed to sweep. Calcium chloride is the best drying agent.

The product is practically white and rather granular; it melts at 96–97°. The yield is 120–123 g. (86–87 per cent of the theoretical amount). The product is fairly reactive and tends to decompose upon standing (Note 3), especially if care is not used in drying and handling. If it is to be used as a starting material for other syntheses, it is advisable to use it as soon as possible.