Patent GB-585574-A (GB)
Title: Improvements in or relating to the production of vitamin concentrates
IPC: A61K31/59
Filed: 1943-07-09
Abstract: A fat-soluble vitamin concentrate, essentially of vitamin A and/or D esters, stated to be of improved taste and odour (and, optionally, also one containing vitamin alcohols) is obtained by treating a fat-soluble vitamin containing marine oil, preferably fish liver oil, optionally at temperatures above room temperature, with a substantially anhydrous liquid aliphatic or alicyclic solvent other than methanol or ethanol, miscible with the oil at temperatures above room temperature and partially immiscible therewith at temperatures below room temperature; cooling the mixture to a temperature within the range of 0 DEG  C. to -70 DEG  C. until two immiscible layers are formed; separating the two layers and where necessary removing the solvent from the vitamin semi-concentrate in the solvent layer; treating the semi-concentrate with a highly polar solvent containing sufficient water to be substantially immiscible with the vitamin ester constituent of the semi-concentrate; and causing the mixture of semi-concentrate and solvent to form into two layers by cooling, separating the solvent layer from the vitamin ester concentrate and advantageously removing the polar solvent to obtain a concentrate rich in vitamin alcohols.  When a substantially anhydrous solvent is used in the first solvent treatment the second solvent treatment may be effected by adding sufficient water to the solution to make the vitamin ester substantially immiscible therewith on cooling. Optionally, the vitamin alcohols and vitamin esters may be separated by continuous extraction methods.  Specified marine oils are: liver oil of cod, shark, tuna, halibut, mackerel, ling cod, sole, spear fish, sword-fish, whale and seal, and sardine oil.  Specified solvents used in the first solvent treatment are: aliphatic and alicyclic monohydroxy alcohols containing from 3 to 6 carbon atoms; esters containing not more than 8 carbon atoms formed by the reaction of aliphatic and alicylic alcohols with aliphatic monocarboxylic acids, aliphatic aldehydes containing not more than 6 carbon atoms; aliphatic ketones containing not more than 6 carbon atoms. Specified polar solvents used in the second solvent treatment are: methyl, ethyl, isopropyl, and n-propyl alcohols, acetone, diacetone alcohol, methyl acetate, ethyl acetate, and methyl ethyl ketone, the last seven named solvents each containing at least 9 per cent of water. Specified polar functional groupings are: hydroxyl, carboxyl and ester.  In examples: (1) a solution of shark liver oil in 99 per cent isopropanol is warmed to 35 DEG  C. in a nitrogen atmosphere cooled to -25 DEG  C. to form two layers, one of solidified oil, and the other an isopropanol solution of vitamin A from which the solvent is distilled under reduced pressure.  The resulting semi-concentrate is heated with methanol in a nitrogen atmosphere to 50 DEG  C. and then cooled to -18 DEG  C. to separate the methanol fraction from the vitamin A ester concentrate which is further freed from methanol by distillation.  The methanol fraction is supplemented by fractions obtained by further methanol extraction of the vitamin ester concentrate and the methanol is then distilled away in vacuo to obtain vitamin A alcohol concentrate.  (2) The semi-concen trate of vitamin A alcohol and ester obtained as in the previous example is continuously extracted at 0 DEG  C. with 95 per cent ethanol to obtain an ethanol solution of vitamin A alcohol and a vitamin A ester concentrate. (3) A 99 per cent isopropanol solution of sole liver oil containing vitamin A is warmed to 40 DEG  C. and cooled to -18 DEG C. when the isopropanol soluttion of vitamin A semi-concentrate separates from the solidified oil and is concentrated by distillation under reduced pressure.  On diluting with water to obtain a 91 per cent isopropanol solution of the semi-concentrate and cooling this solution to -27 DEG  C., the vitamin A ester concentrate separates from the isopropanol solution of vitamin A alcohol.  Specifications 393,883, 528,994 and 549,447 are referred to.  In the Specification as open to inspection under Sect. 91, an alternative form of the invention is also specified in which the vitamin containing oil is treated with a highly polar solvent first and the residual oil is next treated to obtain the vitamin ester with a solvent such as is employed in the first step of the preferred form of the invention. It is stated that it may be necessary to dilute certain of such solvents as are used in the first step of the preferred invention either with a small amount of water or with a liquid aliphatic solvent relatively immiscible with fatty oils and accordingly the ambit of the invention allows the use of a liquid aliphatic solvent which is not specified as being substantially anhydrous.  Solvents useful in carrying out the second step of the invention also include a solvent known as Solox.  This subject-matter does not appear in the Specification as accepted.