Title of Invention

"PROCESS AND APPARATUS FOR THE EXTRACTION AND CONCENTRATION OF TOCOPHEROLS"

Abstract

The present invention discloses a process for the extraction and concentration of tocopherols from vegetable oil deodorizer distillate comprising the steps of: (a) flashing the vegetable oil deodorizer distillate at temperatures ranging from 60 to 150°C under vacuum ranging from 40 to 90 mm Hg absolute; (b) charging the resultant feed stream from step (a) to the centre of the column of a "pot column" where the column of the "pot column is having different layers of tower packings; (c) removing the free fatty acids as vapor exiting from the "pot column" as the top cut; (d) transferring from the "pot column" into the "pot still" the bottom concentrate formed in step (c) comprising a mixture of the esterified tocopherols, sterols, oils and waxes. The esters of fatty acids and tocopherols are formed due to a high temperature chemical reaction between the two compounds; (e) distilling the said mixture of the esterified tocopherols, sterols, oils and waxes in the "pot still"; (f) obtaining a concentrate of free tocopherols together with sterols as the distillate from the "pot still" and leaving all the oils and waxes as the residue in the "pot still".

Full Text

2 FIELD OF INVENTION The present invention relates to a novel process and apparatus for the extraction and concentration of tocopherols. BACKGROUND OF INVENTION The tocopherols are a group of compounds which exhibit Vitamin E activity. They are characterized by a 6 chromanol ring and a saturated phytol side chain. There are 3 assymetric carbon atoms at positions 2, 6 and 10 but it is the configuration at position 2 which determines to the largest extent the biological activity. Natural Vitamin E is characterized by all R stereochemistry. RRR a- tocopherol has 1.49 Vitamin E activity B- tocopherol has 0.5 vitamin E activity - tocopherol has one hundredth the activity of -tocopherol. Vegetable oils typically soybean are important raw materials for the commercial production of tocopherols. The percentage of the tocopherols in soybean oil are typically: (Total tocopherols; 100) a- tocopherol: 15 ... highest Vitamin E activity B- tocopherol: 2 3 y- tocopherol: 52 - tocopherol: 31 ... highest antioxidant activity Deodorization is the last step in the refining process of edible oils and is necessary to remove disagreeable flavors and odors present. The tocopherols can be isolated from the deodorizer distillate, produced as a byproduct of vegetable oil processing. The major components of the vegetable oil deodoriser distillate are fatty acids (50 to 60%), tocopherols (4 to 12%), sterols (6 to 18%) and oils and waxes (10 to 25%). Generally chemical refining of the deodorizer distillate is carried out which involves alkali treatment in order to remove most of the fatty acids as alkali soaps and the resultant feed stream comprising a mixture of tocopherols, sterols and fats, oils and waxes has a concentration of 4 to 10% of tocopherols. Hunt et al (US 5,703,252; US 5,670,669; US 5,646,311 and US 5,616,735), respectively have described the recovery of tocopherols from a mixture of tocopherols, fats and sterols by the distillation of fatty acids converted to their esters, with a packed column in sequence with a wiped film evaporator and the simultaneous recovery of tocopherols and sterols, where the tocopherol- sterol mixture is separated into its components by crystallization of the sterols from a blend of organic solvents. 4 Baird et al (US 5,658,433 and US 5,582,692) have described the purification of Vitamin E, from a mixture of fatty acids, tocopherol compounds and sterols by separation into a low boiling point purified fraction of tocopherols and a high boiling point concentrate fraction of triglycerides, which method is maintained in the presence of an inert gas to provide reduced degradation and increased purity of tocopherols. Barnicki et al (WO 96/14311 and US 5,660,691) describes a process for the preparation of tocopherols from, vegetable oil distillate, wherein the process comprises first an esterification reaction of the fatty acids to their esters, followed by a series of distillation steps where components boiling higher and lower than tocopherols are separated and removed. SUMMARY OF THE INVENTION The object of the present invention is to provide a novel and economical process for the extraction and concentration of tocopherols from vegetable oil deodorizer distillate. Accordingly, the present invention provides a process for the extraction and concentration of tocopherols from vegetable oil deodorizer distillate comprising the steps of: (a) flashing the vegetable oil deodorizer distillate at 5 temperatures ranging from 60 to 150°C under vacuum ranging from 40 to 90 mm Hg absolute; (b) charging the resultant feed stream from step (a) to the centre of the column of a "pot column" where the column of the "pot column is having different layers of tower packings; (c) removing the free fatty acids as vapor exiting from the "pot column" as the top cut; (d) transferring from the "pot column" into the "pot still" the bottom concentrate formed in step (b) comprising a mixture of the esterified tocopherols, sterols, oils and waxes. The esters of tocopherol and fatty acids are formed due to a high temperature chemical reaction between the two compounds; (e) Redistilling the said mixture of the esterified tocopherols, sterols, oils and waxes in the "pot still"; (f) obtaining a concentrate of free tocopherols together with sterols as the distillate from the "pot still" and leaving all the oils and waxes as the residue in the "pot still". The present invention also provides an apparatus for the extraction and concentration of tocopherols comprising a "pot column" in sequence with a "pot still" wherein, the column of the "pot column" is having different layers of tower packings, and a reboiler unit precedes the pot of the "pot column" the "pot column" being maintained at a 6 temperature of 200oC to 300°C and a pressure of 1 to 5 mm of Hg; and another reboiler unit precedes the "pot still" the "pot still" being maintained at a temperature of 280°C to 320°C and a vacuum of 0.5 to 0.01 mm of Hg. DETAILED DESCRIPTION OF THE INVENTION Commercial extraction and concentration of tocopherols from the vegetable oil deodorizer distillate disclosed in prior art processes involves esterification of the fatty acids and the fatty acid esters produced are removed by molecular distillation, wherein a thin film or wiped film evaporator having a short distillation path is used for minimizing the residence time in the molecular distillation still, in order to prevent the deterioration of the heat sensitive sterols and tocopherols. The tocopherols and sterols are separated by cooling the residual reaction mixture, adding water or other suitable solvent, when the tocopherols pass into solution and the sterols precipitate out and can be purified by fractional crystallization. Further molecular distillation is required to produce a fraction containing a high concentration of tocopherols. The process of the present invention is novel as it requires no expensive chemicals, no special solvents for crystallization and purification, and most importantly no expensive molecular distillation apparatus. The vegetable oil distillate (VOD) collected from various edible oil refineries is filled in storage tanks and stored under inert conditions. Constant circulation is maintained under inert conditions at temperatures ranging between 40°c and 80°C. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS FIG. 1 provides a process flow diagram for the first stage distillation of the two stage distillation process taking place in the "pot column". FIG. 2 provides a process flow diagram for the second stage distillation of the two stage distillation process taking place in the "pot still". In the present invention a "pot column" is in sequence with a "pot still". The "pot column" and "pot still" are designed providing reboiler units preceding the pot of both the "pot column" and the "pot still", with minimum residence time of the feed stream in the reboiler units to avoid over exposure to a hot surface, thus eliminating the need for an expensive short path or thin film distillation unit. A two stage distillation process is used without the use of any chemicals or solvents for the distillation and fractionation of the vegetable oil deodorizer distillate. In the first stage of the distillation process the vegetable oil deodorizer distillate is subjected to "flashing" to remove moisture and odiferous compounds which 3 are undesirable low boiling compounds. It is then introduced at the centre of the column of a "pot column" in which the column of the "pot column" is having different layers of tower packings and maintained at a temperature of 200°C to 300°C and a pressure of 1 to 5 mm of Hg, where the different layers of the tower packings have a minimum pressure drop not exceeding 0.05 mbar per meter of the column. In the "pot column", a reaction between 50 to 80% of tocopherols with 98% of the fatty acids takes place to form the tocopherol fatty acid ester. The ester' breaks down yielding free tocopherols and the free fatty acids exit as vapor as the top cut from the "pot column" and are sent to the fatty acid storage tank. A second distillation takes place of the bottom concentrate from the "pot column", in the "pot still". The bottom concentrate comprises a mixture of the esterified tocopherols, sterols, oils and waxes. On distillation in the "pot still" a concentrate of ester free tocopherols together with sterols forms the distillate which is sent via a condensor to the distillate receiver and then to the product concentrate tank and the residue in the "pot still" are a mixture of polymerized oils and waxes which are sent to the bottoms receiver. As a result of the two stage distillation process a minimum of 98% of free fatty acids together with low boilers and 100% of the oils and waxes are removed. Further, a concentration of the tocopherols and sterols is achieved with a final tocopherol concentration ranging between 12 to 15%. The process of the present invention is a continuous concentration process of tocopherols involving minimum start up and shut down losses resulting in low operating and processing cost. The following example is included by way of illustration and does not in any way restrict the scope of the invention. Example The vegetable oil deodorizer distillate has a composition of free fatty acids 50%, tocopherols 4%, sterols 6%, oils and waxes 20% and low boilers 1%. The vegetable oil deodorizer distillate is fed at a feed rate of 600 1ph to the middle of the "pot column" which is maintained at a vacuum of 2 to 5 mm of Hg and at a temperature of 240oC to 280°C. The fatty acids are combined with about 60% of the tocopherols of the feed stream to form the tocopherol fatty acid ester which undergoes distillation and the fatty acid vapor exit the "pot column" at a rate of 300 1ph as the top cut yielding free tocopherols. The bottom concentrate transferred to the "pot still" comprises a mixture of tocopherols, sterols, oils and waxes which exit the "pot column" as the bottom cut at the rate of 300 1ph. The "pot still" is maintained under vacuum at 0.5 10 to 0.01 mm of Hg and a temperature of 280°C to 320°C where a second distillation takes place to separate the mixture of tocopherols and sterols as a concentrate from the residue of oils and waxes. The concentration of tocopherols obtained is 15%. 11 WE CLAIM: 1. A process for the extraction and concentration of tocopherols from vegetable oil deodorizer distillate comprising the steps of: (a) flashing the vegetable oil deodorizer distillate at temperatures ranging from 60 to 15O°C under vacuum ranging from 40 to 90 mm Hg absolute; (b) charging the resultant feed stream from step (a) to the centre of the column of a "pot column" where the column of the "pot column is having different layers of tower packings; (c) removing the free fatty acids as vapor exiting from the "pot column" as the top cut; (d) transferring from the "pot column" into the "pot still" the bottom concentrate formed in step (c) comprising a mixture of the esterified tocopherols, sterols, oils and waxes. The esters of fatty acids and tocopherols are formed due to a high temperature chemical reaction between the two compounds; (e) distilling the said mixture of the esterified tocopherols, sterols, oils and waxes in the "pot still"; (f) obtaining a concentrate of free tocopherols together with sterols as the distillate from the "pot still" and leaving all the oils and waxes as the residue in the "pot still". 12 2. A method as claimed in claim 1, wherein the "pot column" is maintained at a temperature of 200 °C to 300°C and at a pressure of 1 to 5 m of Hg, and has the different layers of tower packings having a minimum pressure drop not exceeding 0.05 mbar per meter of the column. 3. A method as claimed in any preceding claim, wherein the "pot still" is maintained under vacuum at 0-5 to 0.01 mm of Hg and at a temperature of 280°C to 320°C. 4. An apparatus for the extraction and concentration of tocopherols comprising a "pot column" in seguence with a "pot still" wherein, the column of the "pot column" is having different layers of tower packings, and a reboiler unit precedes the pot of the "pot column" the "pot column" being maintained at a temperature of 200oC to 300oC and at a pressure of 1 to 5 mm of Hg; and another reboiler unit precedes the "pot still" the "pot still" being maintained at a temperature of 280°C to 320°C and a vacuum of 0.5 to 0.01 mm of Hg. 5. An apparatus as claimed in claim 4, wherein the different layers of the tower packings have a minimum pressure drop not exceeding 0.05 mbar per meter of the column. 13 6. A process for the extraction and concentration of tocopherols from vegetable oil deodorizer distillates, substantially as herein described, particularly with reference to the example and the accompanying drawing. 7. An apparatus for the extraction and concentration of tocopherols substantially as herein described, particularly with reference to the example and the accompanying drawing. The present invention discloses a process for the extraction and concentration of tocopherols from vegetable oil deodorizer distillate comprising the steps of: (a) flashing the vegetable oil deodorizer distillate at temperatures ranging from 60 to 150°C under vacuum ranging from 40 to 90 mm Hg absolute; (b) charging the resultant feed stream from step (a) to the centre of the column of a "pot column" where the column of the "pot column is having different layers of tower packings; (c) removing the free fatty acids as vapor exiting from the "pot column" as the top cut; (d) transferring from the "pot column" into the "pot still" the bottom concentrate formed in step (c) comprising a mixture of the esterified tocopherols, sterols, oils and waxes. The esters of fatty acids and tocopherols are formed due to a high temperature chemical reaction between the two compounds; (e) distilling the said mixture of the esterified tocopherols, sterols, oils and waxes in the "pot still"; (f) obtaining a concentrate of free tocopherols together with sterols as the distillate from the "pot still" and leaving all the oils and waxes as the residue in the "pot still".

Documents:

00260-cal-2001-abstract.pdf

00260-cal-2001-assignment.pdf

00260-cal-2001-claims.pdf

00260-cal-2001-correspondence.pdf

00260-cal-2001-description(complete).pdf

00260-cal-2001-drawings.pdf

00260-cal-2001-form-1.pdf

00260-cal-2001-form-18.pdf

00260-cal-2001-form-2.pdf

00260-cal-2001-form-3.pdf

00260-cal-2001-g.p.a.pdf

00260-cal-2001-letters patent.pdf

00260-cal-2001-reply f.e.r.pdf

260-CAL-2001-FORM 27.pdf

260-CAL-2001-FORM-27-1.pdf

260-CAL-2001-FORM-27.pdf