Org. Synth. 1929, 9, 50
DOI: 10.15227/orgsyn.009.0050
LEVULINIC ACID
Submitted by B. F. McKenzie
Checked by H. T. Clarke and R. Phillips.
1. Procedure
To a solution of
500 g. (1.46 moles) of cane sugar (Note 1) in 1 l. of water in a
2-l. flask is added
250 cc. of concentrated hydrochloric acid (sp. gr. 1.16). The flask is heated on a
steam bath for twenty-four hours, during which time considerable carbonization takes place. The black solid is filtered off with suction and washed with 300 cc. of water. The filtrate is placed in a
large evaporating dish on a steam bath and allowed to evaporate overnight. The black solid residue obtained on the following morning is ground to a powder and placed in a
folded filter paper of 34-cm. diameter. This is placed in a
25-cm. funnel fitted with a
water-cooled 12-l. flask as described on
p. 375. The solid is extracted with
500 cc. of ether for six to eight hours. The ether is distilled and the residue
(Note 2) fractionated under reduced pressure. The fraction distilling at
150–160°/15 mm. or
135–140°/10 mm. forms a rather dark liquid which does not completely solidify on cooling.
On redistillation under reduced pressure a fraction boiling over a range of not more than 2° (e.g., 137–139°/10 mm.) is obtained with very little loss; this fraction solidifies almost completely at 30°. The yield is 72–76 g. (21–22 per cent of the theoretical amount).
2. Notes
1.
Equally good results may be obtained with
starch; the mixture however, must be warmed more slowly as it is apt to foam at the outset.
2.
When larger quantities of
levulinic acid are to be prepared it has been found by the
checkers to be more convenient to fractionally distil the first filtrate under reduced pressure, without evaporating to dryness and extracting with ether. In this case a considerable quantity of tarry residue remains in the
distilling flask. The yields are equally good.
3. Discussion
The only practical methods for preparing
levulinic acid depend upon the action of mineral acids upon carbohydrates, a reaction discovered by Grote and Tollens,
1 who heated
cane sugar with dilute
sulfuric acid. The procedure described is essentially that of Conrad,
2 descriptions of which frequently have appeared
3 in the subsequent literature. Improved yields have been reported
4 by digesting
sucrose under pressure for one hour with dilute
hydrochloric acid at 162° in the presence of water vapor. The use of distillation under reduced pressure was suggested by Kent and Tollens.
5 Levulinic acid can also be prepared from
starch6 and from
glucose7 by the action of
hydrochloric acid, and from
furfuryl alcohol or hydroxymethylfurfural by the action of dilute mineral acids.
8
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
cane sugar
starch
sulfuric acid (7664-93-9)
hydrochloric acid (7647-01-0)
ether (60-29-7)
sucrose
Furfuryl alcohol (98-00-0)
LEVULINIC ACID (123-76-2)
glucose (492-62-6)
hydroxymethylfurfural
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