Cholesterol → Cholesteryl hemisuccinate

As shown in FIG. 1, butterfat 102 at a fluid temperature greater than 40° C. is continuously introduced at a predetermined rate (e.g., 10 lb/min) into a continuous reactor system 104, which is maintained at a reaction temperature of 170° C. Molten succinic anhydride 106 is metered from storage tank 106 into reactor 104 together with a recycle succinic anhydride stream 108, which will be described in more detail hereinafter. The combined succinic anhydride streams 106, 108 are metered into the continuous reactor system 104 at a temperature of 170° C. at a predetermined rate (e.g., 0.78 pounds per minute) which provides a substantial molar excess with respect to the cholesterol, moisture and mono and diglycerides content of the butterfat 102. The reactor 104 maintains the butterfat and the succinic anhydride at reaction temperature under conditions of mixing, and may be a multitubular reactor, a continuous staged horizontal reactor, a vertical reactor, or one or more serially connected continuously stirred tank reactors, or other suitable reactors. The reaction conditions are maintained in the reactor for a time period of less than about one hour, which is sufficient to react substantially all of the free cholesterol of the butterfat 102 with the succinic anhydride 106 to form cholesteryl hemisuccinate. The resulting reaction mixture, containing butterfat, cholesteryl hemisuccinate and excess succinic anhydride, is conducted to liquid/liquid centrifuge 110 (e.g., at a rate of 10.78 pounds per minute) where the more dense, excess succinic anhydride phase 108 (e.g.,at a rate of about 0.77 pounds per minute) is separated and returned to the reactor 104, as succinic anhydride stream 108.