Organic Syntheses, Coll. Vol. 3, p.278 (1955); Vol. 27, p.21 (1947).
A solution of 24 g. (0.6 mole) of sodium hydroxide
, 100 ml. of water, and 55 g. (0.5 mole) of resorcinol
is placed in an apparatus for high-pressure hydrogenation together with 10 g. of reduced Universal Oil Products hydrogenation catalyst (Note 1)
or Raney nickel
(see p. 181
). The pressure in the bomb is raised to 1000–1500 lb. with hydrogen
, and the temperature is adjusted to 50° (Note 2)
. The bomb is shaken and the reaction allowed to proceed for 10 to 12 hours, during which time 0.5 mole of hydrogen
is absorbed (Note 3)
The apparatus is allowed to cool to room temperature, the pressure is released, and the catalyst is removed by filtration. The filtrate is made acid to Congo red with concentrated hydrochloric acid
, and the solution is cooled to 0° in an ice-salt bath
and held at that temperature for 30 minutes before filtration. The dihydroresorcinol
which crystallizes is separated by filtration and dried; 50–60 g.
of crude dry product containing sodium chloride
The crude dihydroresorcinol
is dissolved in 125–150 ml. of hot benzene
, filtered to remove the sodium chloride
, and allowed to crystallize. The solid is separated by filtration and dried overnight in a vacuum desiccator
. The product melts at 103–104°
and weighs 48–53 g
) (Note 4)
The Universal Oil Products hydrogenation catalyst consists of a mixture of nickel
, nickel oxides
, and kieselguhr
compressed into pills containing 50–55% nickel. Before use in a liquid-phase hydrogenation of this sort, the catalyst must be reduced in a stream of hydrogen
at 430°. The reduced catalyst is cooled in the stream of hydrogen
and may be kept under alcohol. It also may be saturated with carbon dioxide
and kept in a sealed bottle. The pilled material should be pulverized before use in this preparation. The pelleted Universal Oil Products hydrogenation catalyst may be purchased from Universal Oil Products Company, 310 S. Michigan Ave., Chicago 4, Illinois.
It is particularly important that the temperature should not rise above 50°; at higher temperatures complex condensation products result.
It is important that hydrogenation be complete; incompletely hydrogenated material yields an oily product which is exceedingly difficult to crystallize. The usual time of hydrogen
absorption is 4 to 5 hours with Universal Oil Products catalyst and about 4 hours with Raney nickel
. The extra time mentioned in the procedure avoids any chance of incomplete reduction.
is unstable; it can be stored only a short time. If it is not used immediately, it should be stored under an inert gas in a brown bottle in a refrigerator
This preparation is referenced from:
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