Patent GB-770427-A (GB)
Title: Improvements in or relating to non-toxic soya-bean phosphatide fat emulsifiers
IPC: C07F9/10
Filed: 1954-09-10
Abstract: A stabilized soya bean phosphatide emulsifier is obtained by contacting a crude mixture of soya bean phosphatides containing catalyst poisons with a solvent mixture containing at least one non-polar solvent in which the emulsifying principles and catalyst poisons present in said mixture are soluble, and at least one polar solvent in which the emulsifying principles are of at least limited solubility and the catalyst poisons are substantially insoluble, regulating the relative proportions of the polar and nonpolar solvents so that substantially all of the emulsifying principles present in the crude mixture dissolve in the solvent mixture while the catalyst poisons are insoluble in said mixture, separating the solvent mixture containing the emulsifying principles substantially free of catalyst poisons, and subsequently subjecting the emulsifying principles to catalytic hydrogenation.  In one embodiment the crude phosphatides can be extracted with a mixture of the polar and non-polar solvents in which the proportion of the solvents has been suitably regulated but it is preferable to first dissolve all of the crude material in a non-polar solvent and then to add the polar solvent to the solution.  If the solvents are miscible in the desired proportions the catalyst poisons will be thrown out of solution so that they can be separated as a precipitate.  If the solvents are not miscible at the concentrations employed the emulsifying principles will be extracted into the phase rich in polar solvent, the catalyst poisons being left behind in the phase rich in non-polar solvent. The non-polar solvent may be a hydrocarbon solvent such as cyclohexane, methyl cyclohexane, petroleum ether or Skelly-Solve, whilst specified polar solvents are oxygen-containing solvents such as methanol, ethanol, isopropanol, butanol, and dioxane.  It is preferred to dissolve the crude material in cyclohexane and to add about an equal portion of methanol to form two phases, the desired phosphatides being extracted into the methanol-rich phase while the catalyst poisons remain in the cyclohexane-rich phase.  The phases are then separated and the extract in the methanol-rich phase subjected to hydrogenation to produce a stabilized soya bean phosphatide emulsifier which can be used to prepare fat emulsions suitable for intravenous injection and containing up to 40 per cent fat suspended in the form of small particles.  It is desirable to filter the solution of the crude phosphatide material in the non-polar solvent before adding the polar solvent, and, if desired, a bacterial filter can be employed to effect sterilization of the solution at this point.  It is also desirable to concentrate the methanol-rich phase after separating it from the hydrocarbon-rich phase before subjecting it to hydrogenation, e.g. by vacuum distillation of the methanol-rich phase until it is substantially saturated with the phosphatides or until a precipitate of the phosphatides begins to form.  After the hydrogenation the hydrogenated phosphatide is recovered, e.g. by precipitating the product with acetone or by removing the hydrogenation catalyst and concentrating the solution to dryness. The hydrogenation need only be carried out to such an extent as to eleminate the conjugated double bonds.  Specified hydrogenation conditions are: (a) a hydrogen gas pressure of about 50 to 1500 pounds per square inch, (b) a temperature of 50 DEG  to 150 DEG  C., and (c) any standard hydrogenation catalyst in the usual proportions, e.g. 0.1 per cent or more by weight of platinum oxide or about 1 per cent or more by weight of Raney nickel. Examples are given for the treatment of commercial lecithin using cyclohexane and methanol, cyclohexane and ethanol, and Skellysolve and isopropanol as solvents and using Raney nickel and platinum oxide as hydrogenation catalysts.  In one of the examples commercial lecithin is dissolved in cyclohexane, the solution filtered through a bacterial filter, added to methanol and the methanol-rich fraction concentrated and hydrogenated using platinum oxide as catalyst.  Specification 770,426 is referred to.