Patent GB-490433-A (GB)
Title: Improvements in processes of high vacuum-short path distillation
IPC: B01D3/34
Filed: 1937-02-15
Abstract: In the high-vacuum short-path distillation of substances yielding fractions containing vitamins, sterols, hormones or unsaturated glycerides, or a fraction obtained therefrom still requiring distillation, another liquid is added to the distilland having a vapour pressure lower than that of the distillate under the conditions appertaining, so as to prevent deposition of non-volatile residuum upon the distilling surface.  Original materials specified comprise animal oils such as salmon, menhaden, cod - liver, herring, halibut, and mackerel oils; vegetable oils such as linseed, walnut, wheat-germ, cotton-seed, and soya-bean oils, waxes containing unsaturated glycerides; and germinal gland hormone concentrates. Examples of suitable added liquids comprise esters such as benzyl, butyl, amyl, and octyl phthalates, triacetine, methyl oleate, methyl stearate, oils such as olein or castor oil; high boiling-point hydrocarbons; high boiling-point alcohols; and the lowest vapour pressure fraction of the material being distilled.  The proportions of distilland and added liquid may vary from 1/200 part to 25 parts of the latter to 1 of distilland.  The added liquid may be separated from the distilland and re-used and this separation is facilitated by using a liquid immiscible at ordinary temperatures, but miscible with the distilland at the temperature of distillation.  Molecular distillation may be used, and the temperatures, pressures, and distance apart of the evaporating and condensing surfaces may all be varied according to the particular distilland.  In an example, linseed oil is subjected to molecular distillation at temperatures between 140-225 DEG  C. and four fractions withdrawn leaving 5 per cent of the oil as a viscid mass in the last column. Distillation of fresh material is continued until the latter accumulates.  This viscous oil is then returned and mixed with the oil entering the same column.  U.S.A.  Specifications 1,925,559, 1,942,858, and 1,955,321 are referred to.ALSO:In the high-vacuum short-path distillation of substances yielding fractions containing vitamins, or sterols, or a fraction obtained therefrom still requiring distillation, another liquid is added to the distill and having a vapour pressure lower than that of the distillate under the conditions appertaining so as to prevent deposition of non-volatile residuum upon the distilling surface.  Original materials specified comprise animal oils such as salmon, menhaden, cod liver, herring, halibut, mackerel; and vegetable oils such as linseed, walnut, wheat-germ, cotton-seed, soya bean Examples of suitable added liquids comprise esters such as benzyl, butyl, amyl, and octyl phthalates, triacetine, methyl oleate, methyl stearate; oils and hydrocarbons such as olein, castor oil, high boiling point hydrocarbons; high boiling point alcohols; and the lowest vapour pressure fraction of the material being distilled.  The proportions of distilland and added liquid may vary from 1/200 part to 25 times of the latter to 1 of distilland.  The added liquid may be separated from the distilland and re-used and this separation is facilitated by using a liquid immiscible at ordinary temperatures but miscible with the distilland at the temperature of distillation. Molecular distillation may be used, and the temperatures, pressures and distance apart of the evaporating and condensing surfaces may all be varied according to the particular distilland.  In an example, linseed oil is subjected to molecular distillation at temperatures between 150-225 DEG  C. and four fractions withdrawn leaving 5 per cent of the oil as a viscid mass in the last column. Distillation of fresh material is continued until the latter accumulates.  This viscous oil is then returned and mixed with the oil entering the same column.  U.S.A. Specifications 1,925,559, 1,942,858, and 1,955,321 are referred to.ALSO:In the high vacuum short-path distillation of substances yielding fractions containing hormones or a fraction obtained therefrom still requiring distillation, another liquid is added to the distilland having a vapour pressure lower than that of the distillate under the conditions appertaining so as to prevent deposition of non-volatile residuum upon the distilling surface. Original materials specified comprise germinal gland hormone concentrates.  Examples of suitable added liquids comprise esters such as benzyl, butyl, amyl, and octyl phthalates, triacetin, methyl oleate, methyl stearate; oils and hydrocarbons such as olein, castor oil, high boiling point hydrocarbons; high boiling point alcohols; and the lowest vapour pressure fraction of the material being distilled.  The proportion of distilland and added liquid may vary froms 1/200 part to 25 parts of the latter to 1 of distilland.  The added liquid may be separated from the distilland and re-used and this separation is facilitated by using a liquid immiscible at ordinary temperatures but miscible with the distilland at the temperature of distillation.  Molecular distillation may be used, and the temperatures, pressures and distance apart of the evaporating and condensing surfaces may all be varied according to the particular distilland.  U.S.A. Specifications 1,925,559, 1,942,858, and 1,955,321 are referred to.