Recovery of L-Dopa from R-dopa containing materials
AssigneeBio-Derivatives Corporation
InventorGuy J. Riccardi
Life of this patent
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Abstract
L-Dopa is recovered from velvet bean and other L-Dopa containing materials by water extraction, preferably carried out at a temperature in the range 15-25.degree.C. The resulting L-Dopa aqueous extract is then concentrated and the resulting concentrated extract treated or cooled to crystallize L-Dopa therefrom.
Claims19
A method for the recovery of L-Dopa from L-Dopa-containing material which comprises extracting L-Dopa from said material by contacting said material with substantially acid-free water, separating the resulting aqueous extract, now containing L-Dopa dissolved therein, from the resulting extracted material, concentrating the resulting aqueous extract with the removal of at least about 50% of the water content therefrom and separating L-Dopa from the resulting concentrated aqueous extract by crystallization.
A method for the recovery of L-Dopa from L-Dopa-containing material which comprises extracting L-Dopa from said material by contacting said material with substantially acid-free water, separating the resulting aqueous extract, now containing L-Dopa dissolved therein, from the resulting extracted material, adding to the resulting aqueous extract an amount of SO.sub.2 sufficient to prevent oxidation of the L-Dopa in the aqueous extract, concentrating the resulting aqueous extract and separating L-Dopa therefrom by crystallization.
A method for the recovery of L-Dopa from ground velvet bean which comprises grinding velvet bean to a mesh size of approximately 10-20 mesh, contacting the ground velvet bean with distilled water at a temperature in the range from about 15.degree. to about 25.degree.C. to extract L-Dopa therefrom, the amount of water employed to extract the L-Dopa from the ground velvet bean being about 36 liters of water per kilogram of ground velvet bean, separating the extracted ground velvet bean from the aqueous extract containing L-Dopa dissolved therein, treating the resulting aqueous extract with gaseous SO.sub.2 in an amount effective to prevent oxidation of the L-Dopa therein, filtering the resulting aqueous extract to remove suspended solids, concentrating the resulting treated aqueous extract by subjecting the extract to evaporation at a reduced pressure to remove about 90% of the water therefrom, the concentration operation being carried out at a temperature in the range about 30.degree.-95.degree.C., subjecting the resulting concentrate to decolorization by contact with activated carbon at a temperature in the range 85.degree.-95.degree.C., filtering the resulting decolorized concentrate to remove suspended solids therefrom, cooling with agitation the resulting filtered concentrate to a temperature in the range from about 0.degree. to about 5.degree.C. to crystallize L-Dopa, separating the resulting crystallized L-Dopa by filtration, washing the resulting separated L-Dopa crystals with water at a temperature of about 0.degree.C. followed by a second washing operation with a washing liquid selected from the group consisting of ethyl alcohol and a mixture of ethyl alcohol and ethyl ether.
A method for recovering 3-(3,4-dihydroxyphenyl)-L-alanine from comminuted beans containing it, which comprises the steps of contacting said beans with a reagent consisting essentially of liquid water at a temperature in the range about 5.degree.-100.degree.C. for a period of time to dissolve a substantial portion of the 3-(3,4-dihydroxyphenyl)-L-alanine therein, separating the extract phase from the beans and recovering a 3-(3,4-dihydroxyphenyl)-L-alanine product.
Dependencies are inferred from the claim text.