Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Patent
1996-10-28
1998-06-09
Owens, Amelia
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C07D31500
Patent
active
057636265
DESCRIPTION:
BRIEF SUMMARY
The present invention is directed to a process for obtaining maltol and more particularly to a process for obtaining pure maltol.
Maltol (3-hydroxy-2-methyl-4H-pyran-4-one) is a heterocyclic aroma chemical used extensively in flavor, fragrance and in some pharmaceutical compositions. Maltol occurs naturally in numerous plant species and its isolation from these sources has been reported extensively in the literature. In particular, its isolation from coniferous trees such as larch trees (Larix decidua mill), pine trees and pine needles (Abis alba mill., pinaceae), has been reported since the turn of the century.
U.S. Pat. No. 5,221,756 issued Jun. 22, 1993 refers to a process for the recovery of maltol from a mixture of maltol by co-distillation with an aliphatic or cycloaliphatic hydrocarbon in which the maltol is substantially insoluble; and then condensing the co-distillate to recover substantially pure crystals of maltol.
Maltol has been obtained from the destructive distillation of wood but such process only results in small amounts of maltol. Thus, such a process is economically undesirable.
Fleisher & Fleisher, "Water-soluble Fractions of the Essential Oils", Perfumer and Flavorist, Vol. 16 May/June, pp. 37-41, 1991, refers to the recovery and characterization of compounds from fir needles (Abis balsamea L.).
U.S. Pat. Nos. 3,031,204, 4,082,717 and 4,343,697 refer to processes for the synthesis of gamma pyrones, such as maltol, ethyl maltol and pyromeconic acid.
The present invention is directed to a process for the recovery of maltol comprising:
a) heating a mixture containing maltol in the presence of a substantially water-immiscible solvent in which the maltol in said mixture is substantially insoluble to form an aqueous layer and a solvent layer; and
b) recovering said aqueous layer.
Further preferred is the process wherein maltol is recovered from the aqueous layer.
Preferred is the process wherein said solvent is selected from the group consisting of hexane, .alpha.-pinene and petroleum ether; and combinations thereof.
Also preferred is the process wherein said solvent is hexane.
Also preferred is the process wherein said solvent is .alpha.-pinene.
Also preferred is the process wherein said solvent is petroleum ether.
Especially preferred is the process wherein said mixture is a resin.
Also preferred is the process wherein said resin is derived from solvent extraction of a coniferous species with a preferred coniferous source being needles with especially preferred needles being derived from Abis balsamea L fir trees.
Also preferred is the process wherein the solubility of maltol in said solvent is less than about 0.3% percent by weight at room temperature.
The present invention is also directed to substantially pure maltol produced by the process of the present invention.
In a further embodiment, the present invention is directed to a process for the recovery of maltol comprising
(a) heating an oleoresin containing maltol in the presence of an aqueous solution to create an aqueous layer and a resin layer;
(b) recovering said aqueous layer.
Further preferred is the process wherein maltol is recovered from the aqueous layer.
Especially preferred is the process wherein the oleoresin is derived from solvent extraction of coniferous species with an especially preferred coniferous source being needles with especially preferred needles being derived from Abis balsamea L fir trees.
Also preferred is the process wherein the aqueous solution is added at a weight of from about 0.5 to about 5 times the weight of the oleoresin.
The present invention is directed to a process for the recovery of pure maltol from a mixture containing maltol.
The mixture may be any mixture derived from, for example, plant species or coniferous trees known to contain maltol. Preferably, the mixture is a resin derived from extraction of pine tree needles, or larch tree bark, both sources high in natural maltols. Preferably, the mixture is derived from extraction of needles derived from the fir tree (Abis balsamea L.). The crude
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patent: 4342697 (1982-08-01), Weeks et al.
patent: 5221756 (1993-06-01), Fleisher et al.
Pavia, et al., Intro. to Org. Lab. Tech., Saunders, 1976, pp. 525-528.
Takaishi, K., Phytochemistry 10:3302 (1971).
Dickey Kenneth D.
Guzek Donald B.
Hausman Russell J.
Cultor Ltd.
Owens Amelia
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