Method for the preparation of phytosterols from tall oil pitch

Abstract

A method of preparing phytosterols from tall oil pitch containing steryl esters comprises the steps of converting the steryl esters to free phytosterols while in the pitch to produce a modified pitch containing the free phytosterols; removing light ends from the modified pitch by evaporation to produce a bottom fraction containing the free phytosterols; evaporating the bottom fraction to produce a light phase distillate containing the free phytosterols; dissolving the light phase distillate in a solvent comprising an alcohol to produce a solution containing the free phytosterols; cooling the solution to produce a slurry with the free phytosterols crystallized in the slurry; and, washing and filtering the slurry to isolate the crystallized phytosterols.

1 . A method of preparing phytosterols from tall oil pitch containing steryl esters, said method comprising the steps of:
 (a) converting said steryl esters to free phytosterols while in said pitch to produce a modified pitch containing said free phytosterols;   (b) distilling said modified pitch in a first evaporator to remove light ends from said modified pitch and produce a bottom fraction containing said free phytosterols;   (c) distilling only said bottom fraction in a second evaporator to produce a light phase distillate containing said free phytosterols;   (d) dissolving said light phase distillate in a solvent comprising an alcohol to produce a solution containing said free phytosterols;   (e) cooling said solution to produce a slurry with said free phytosterols crystallized in said slurry; and,   (f) washing and filtering said slurry to isolate said crystallized phytosterols.   
   
   
       2 . A method as defined in  claim 1 , wherein said modified pitch comprises less than 1% water by weight. 
   
   
       3 . A method as defined in  claim 1  or  2 , wherein said solvent comprises a low molecular weight monohydric alcohol. 
   
   
       4 . A method as defined in  claim 1  or  2 , wherein said solvent comprises a low molecular weight monohydric alcohol and water. 
   
   
       5 . A method as defined in  claim 1  or  2 , wherein said slurry is washed and filtered using a solvent like said solvent used to dissolve said light phase distillate. 
   
   
       6 . A method as defined in  claim 1 , wherein said step of converting said steryl esters to free phytosterols comprises the steps of:
 (a) saponifying said tall oil pitch with an alkali metal base;   (b) neutralizing said saponified pitch with an acid; and,   (c) heating said neutralized pitch to remove water, the resulting pitch with such water removed defining said modified pitch.   
   
   
       7 . A method as defined in  claim 6 , wherein said alkali metal base is selected from the group consisting of:
 (a) sodium hydroxide;   (b) potassium hydroxide;   (c) sodium hydroxide and potassium hydroxide.   
   
   
       8 . A method as defined in  claim 7 , wherein in the weight percentage of alkali metal base to tall oil pitch is in the range of 1% to 15%. 
   
   
       9 . A method as defined in  claim 7 , wherein said saponification is conducted at a temperature in the range of 100 to 250 deg. C. for a period in the range of 60 to 300 minutes. 
   
   
       10 . A method as defined in  claim 6 , wherein said acid is an organic acid. 
   
   
       11 . A method as defined in  claim 6 , wherein said acid is a mineral acid. 
   
   
       12 . A method as defined in  claim 11 , wherein said mineral acid is selected from the group consisting of:
 (a) sulphuric acid;   (b) hydrochloric acid;   (c) phosphoric acid;   (d) a combination of acids comprising two or more of sulphuric acid, hydrochloric acid and phosphoric acid.   
   
   
       13 . A method as defined in  claim 6 , wherein said neutralization is conducted at a temperature in the range of 10 to 100 deg. C. for a period in the range of 1 to 10 hours. 
   
   
       14 . A method as defined in  claim 6 , wherein said neutralized pitch has a water phase pH in the range of 4 to 7. 
   
   
       15 . A method as defined in  claim 6 , wherein said heating step comprises heating at a temperature in the range 90 to 100 deg. C. for a time sufficient to effect the bulk disengagement of water from the organic phase. 
   
   
       16 . A method as defined in  claim 15 , wherein said heating step further comprises heating under vacuum conditions such that said modified pitch comprises less than 1% water by weight. 
   
   
       17 . A method as defined in  claim 1  or  6 , wherein said light ends are removed in a wiped film evaporator operating at a pressure in the range of 0.1 to 10 millibars and at a temperature in the range 160 to 280 deg. C. 
   
   
       18 . A method as defined in  claim 1  or  6 , wherein said bottom fraction is evaporated in a wiped film evaporator operating at a pressure in the range of 0.01 to 1.0 millibars and at a temperature in the range 180 to 300 deg. C. 
   
   
       19 . A method as defined in  claim 6 , wherein said solvent comprises a low molecular weight monohydric alcohol. 
   
   
       20 . A method as defined in  claim 6 , wherein said solvent comprises a low molecular weight monohydric alcohol and water. 
   
   
       21 . A method as defined in  claim 1  or  6  in which the crystallization of phytosterols is effected at a temperature in the range of 0 to 35 deg. C. 
   
   
       22 . A method of preparing phytosterols from tall oil pitch containing steryl esters, said method comprising the steps of:
 (a) converting said steryl esters to free phytosterols while in said pitch to produce a modified pitch containing said free phytosterols;   (b) distilling said modified pitch in a first evaporator to remove light ends from said modified pitch and produce a bottom fraction containing said free phytosterols;   (c) distilling only said bottom fraction in a second evaporator to produce a light phase distillate containing said free phytosterols;   (d) re-distilling only said light phase distillate to enhance the concentration of free phytosterols in said light phase distillate;   (e) dissolving only said re-distilled light phase distillate in a solvent comprising an alcohol to produce a solution containing said free phytosterols;   (f) cooling said solution to produce a slurry with said free phytosterols crystallized in said slurry; and,   (g) washing and filtering said slurry to isolate said crystallized phytosterols.   
   
   
       23 . A method as defined in  claim 22 , wherein said solvent further comprises water added in a proportion up to 35% by weight relative to the organic solvent phase. 
   
   
       24 . A method as defined in  claim 23 , wherein the weight ratio of solvent to distillate is between 0.3 to 2.0. 
   
   
       25 . A process according to  claim 19 ,  20  or  24  in which the alcohol is selected from:
 (a) methanol;   (b) ethanol;   (c) 2-propanol;   (d) a combination of alcohols comprising two or more of methanol, ethanol and 2-propanol.   
   
   
       26 . Phytosterols prepared from tall oil pitch in accordance with the method as defined in any one or more of the preceding claims.