CROSSREFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U. S. Provisional Application No.

62/769,862, filed November 20, 2018, which is incorporated herein in its entirety by reference.

BACKGROUND

[0002] In preparing acids, inexpensive starting materials, such as natural oils, fats, or other fatty materials, can be used. The oils and/or fats can be subjected to splitting to release fatty acids. Examples of such splitting processes include hydrolysis by pressure splitting and enzymatic splitting. After splitting, the fatty acids can contain impurities, such as unsplit or incompletely split glycerides (for example, monoglycerides, diglycerides, or a combination comprising at least one of the foregoing), color bodies, steroid alcohols, and phosphatides. “Color bodies” refer to impurities that discolor an oil, fat, or fatty acid product. Examples of color bodies include tocopherols and pigments, for example, chlorophylls and carotenoids.

[0003] Processes for preparing fatty acids derived from oils and/or fats with a phosphorus content below 200 parts per million by weight (ppm), in good yield, and with good color and color stability, include hydrolytic splitting of degummed oils and/or fats, at least one thermal pre-treatment of a composition comprising crude fatty acids, and high vacuum distillation of the thermally pretreated composition comprising crude fatty acids.

[0004] It would be desirable to improve conversion of oils and/or fats to fatty acids.

SUMMARY

[0005] Disclosed, in various embodiments, are processes of preparing fatty acids from oils and/or fats.

[0006] A process for preparing fatty acids, comprises: forming a crude fatty acid product by splitting a feedstream comprising oils and/or fats in a splitting column; fractioning the crude fatty acid product into a short chain fatty acid stream, a long chain fatty acid stream, and a residual product stream in a fractionating distillation column; mixing the short chain fatty acid stream with a whitening compound during distillation in a first distillation column, forming an intermediate short chain fatty acid stream; and purifying the intermediate short chain fatty acid stream by distilling the intermediate short chain fatty acid in a second distillation column, forming a free fatty acid; wherein impurities and unmixed whitening compound is removed from the intermediate short chain fatty acid in the residual product stream.

[0007] The above described and other features are exemplified by the following detailed description.

BRIEF DESCRIPTION OF THE DRAWING

[0008] The following is a brief description of the drawing wherein like elements are numbered alike and which is presented for the purposes of illustrating the exemplary embodiments disclosed herein and not for the purposes of limiting the same.

[0009] The Figure is a schematic view of a reactor configuration used in the process disclosed herein.

DETAILED DESCRIPTION

[0010] Disclosed herein are processes of preparing fatty acids from oils and/or fats. The process can include fractioning a crude fatty acid product formed by splitting a feedstream including oils, fats, or a combination comprising at least one of the foregoing in a splitting column. The crude fatty acid product can be fractioned in a fractionating distillation column into a short chain fatty acid stream, a long chain fatty acid stream, and a residual product stream. This can be followed by mixing the short chain fatty acid stream with a whitening compound during distillation in a first distillation column, thereby forming an intermediate short chain fatty acid stream. A free fatty acid can be formed by purifying the intermediate short chain fatty stream after distillation in a second distillation column.

Impurities and unmixed whitening compounds can be removed from the intermediate short chain fatty acid in the residual product stream. The process described herein can allow for recovery of at least 95 weight percent (wt%) of free fatty acids from the short chain fatty acid stream, for example, at least 96 wt%, for example, at least 98 wt%, for example, at least 99 wt% of free fatty acids from the short chain fatty acid stream.

[0011] Color stability of a fatty acid can be a concern when used in applications such as pharmaceuticals, food, drugs, cosmetics, and the like. Due to un-saturation of the fatty acid, high color impurities and low oxidation stability can drastically increase the color value of the fatty acid, leading to an off-spec product For example, a color value of the fatty acid not prepared by the processes disclosed herein can be 0.5 red (R) and 3 yellow (Y) initially, and once heated, will increase to 10 R and 15 Y, wherein color is measured based on the LOVIBOND™ RYBN color scale in accordance with, for example, the standards defined in AOCS Method Cc 13b-45 or ISO Method 27608:2010.

[0012] The glycerides are widely available in nature as oils and fats. During the splitting process, undesirable polymerization and decomposition reactions can occur, which can result in further contamination of the crude fatty acids. The crude fatty acid product obtained by the pressure splitting of fats and oils generally comprises about 95 wt% to about 99 wt% of free fatty acids based on the weight of the crude fatty acid product and about 1 wt% to about 5 wt% of impurities, wherein the impurities can include un- split glycerides, color bodies, sterols, phosphatides, or a combination comprising at least one of the foregoing. “Color bodies” refer to impurities that discolor an oil, fat, or fatty acid product. Examples of color bodies include tocopherols and pigments, for example, chlorophylls and carotenoids. Minor amounts of water and other compounds can also be present. Minor generally refers to amounts of less than or equal to 0.2 wt%.

[0013] In the process disclosed herein, a small amount, e.g., 50 ppm to 1000 ppm, of a whitening agent can be mixed with short chain fatty acids during distillation. In some instances, the short chain fatty acid mixture can be treated at elevated temperatures of 30 to 100°C, for 15 to 30 minutes. Thereafter, the short chain fatty acid product can be distilled at a pressure of 1 kilopascals (kPa) to 16 kPa in order to provide purified fatty acids. The whitening agent can remove the coloring components in the mixture, can reduce the oxidation at the surface, and can maintain good color stability during distillation. Good color stability generally refers to color values as measured on the LOVIBOND™ RYBN color scale of 0.3 R and 3 Y.

[0014] A process for improving color and heat stability of low grade Cs-Cio fatty acids derived from a crude fatty acid comprising palm kernel oil can include distilling the Cs- Cio fatty acid in the presence of an inorganic oxygen containing whitening compound in a quantity of 50 ppm to 1000 ppm, for example, 100 ppm to 1000 ppm, based on the weight of the fatty acid. After distillation, the whitening compound (such as boric acid) remains in a residual stream and can be separated easily. The resulting fatty acid can contain less than or equal to 1.0 ppm of the whitening compound, for example, less than or equal to 0.75 ppm, for example, less than or equal to 0.5 ppm. Minor components such as quinindoline, amines, nitriles, and metal complexes, which contribute to discoloration of the fatty acid product can be removed as residual matter into the residual stream after distillation with the whitening compound. Mixing the short chain fatty acid stream with a whitening compound during distillation can form an intermediate short chain fatty acid stream. Mixing can occur at a temperature of 25°C to 125°C, preferably, 30°C to 100°C, e.g., for 15 to 30 minutes. The intermediate fatty acid stream can contain 50 ppm to 1000 ppm, such as 75 ppm to 700 ppm, or 80 ppm to 500 ppm, or 80 ppm to 300 ppm of the whitening agent, based on the weight of the intermediate short chain fatty acid stream. The whitening compound can comprise boric acid, phosphoric acid, an alkyl derivative of phosphoric acid, or a combination comprising at least one of the foregoing, preferably the whitening compound comprises boric acid.

[0015] The process for preparing fatty acids derived from oils and/or fats, in good yield, and with good color and thermal stability, can include splitting of degummed oils and/or fats to provide a crude fatty acid product. Oils and fats that can be split include crude or refined vegetable oils and fats and crude, for example, degummed vegetable oils and fats, such as coconut oil, palm oil, palm kernel oil, sunflower oil, soybean oil, rapeseed oil (e.g., high erucic rapeseed oil), castor oil, linseed oil, safflower oil, com oil, cottonseed oil, groundnut oil, canola oil, or a combination comprising at least one of the foregoing.

Desirable splitting processes to release crude fatty acids from oils and fats include, but are not limited to, hydrolytic splitting processes such as thermal high pressure splitting and enzymatic splitting. Accordingly, the feedstream can comprise palm kernel oil, coconut oil, vegetable oil, safflower oil, canola oil, sunflower oil, or a combination comprising at least one of the foregoing.

[0016] The splitting process can make use of a pressure splitter to which the fat or oil can be introduced at one end and water introduced at the opposite end thereof in a

countercurrent flow pattern. The crude fatty acid product obtained by pressure splitting fats and oils can include about 95 wt% to about 99 wt% of free fatty acids, based on the total weight of the crude fatty acid product, and about 1 wt% to about 5 wt% of impurities, such as unsplit or incompletely split glycerides, color bodies, steroid alcohols, phosphatides, quinindoline, amines, nitriles, metal complexes, or a combination comprising at least one of the foregoing. Minor amounts of water and other compounds can be present. The unsplit or incompletely split glycerides can comprise a monoglyceride, a diglyceride, or a combination comprising at least one of the foregoing.

[0017] During splitting, undesirable polymerization and decomposition reactions can occur, which can result in additional contamination of the crude fatty acids. After splitting, the crude fatty acid product can contain impurities, such as, unsplit or incompletely split glycerides, (for example, monoglycerides, diglycerides, or a combination comprising at least one of the foregoing), color bodies, steroid alcohols, and phosphatides. The crude fatty acid product can be split into fractions of C _6-8 fatty acids, Cs-io fatty acids, C12-14 fatty acids, Ci _6-i8 fatty acids, and residues in a fractionating column.

[0018] The short chain, e.g., C6-10, fatty acid fraction e.g., C ₆ -Cs fatty acids or Cs-io fatty acids can contain impurities and can have a relatively high ester value.

[0019] The ester value of the free fatty acid stream can be less than or equal to 1. The ester value corresponds to esters, for example, monoglycerides, diglycerides, triglycerides, or a combination comprising at least one of the foregoing, present in the free fatty acid stream. The ester value is calculated as the difference between saponification value and acid value of the fatty acids. The acid chloride treatment reduces the esters present in the fatty acids and reduces the difference between saponification value and acid value of the fatty acids to less than or equal to 1. In an embodiment, esters present in the free fatty acid stream, for example, magnesium hydroxide, can be present in an amount of less than 0.5 wt%.

[0020] A free fatty acid stream can be distilled from the short chain fatty acid stream in a distillation column. The distillation can be based on a high vacuum distillation method, for example, thin film evaporation, (centrifugal) molecular distillation, wiped film

distillation, or falling film distillation. The distillation temperature can be 100°C to 140°C and the distillation pressure can be 1 kPa to 16 kPa.

[0021] The free fatty acid produced can have a color value of less than or equal to 65, for example, less than or equal to 55, for example, less than or equal to 50 as measured according to the American Public Health Associate (APHA) color system in accordance with ASTM D1209-05. This is also referred to as the“Hazen” value.

[0022] Turning now to FIG. 1, a process for producing fatty acids is shown. In the process, a feedstream 12 comprising oils and/or fats is sent to a splitting column 20 to form a crude fatty acid product 14. The crude fatty acid product 14 is then sent to a fractionating column 30 to be fractionated into a short chain fatty acid stream 15, a long chain fatty acid stream 16, and a residual product stream 18. Inside the fractionating column 30, the short chain fatty acid stream 15 is exposed to a whitening agent to remove impurities present in the short chain fatty acid stream 15 by removing the coloring components in the mixture, reducing oxidation at the surface, and maintaining good color stability during distillation by maintaining a color value of less than or equal to 65 as measured in accordance with ASTM D 1209-05. The shorty chain fatty acid stream 15 is sent to a distillation column 40 to form a free fatty acid 22.

[0023] An ester value of the free fatty acid can be less than or equal to 1. The feedstream can comprise palm kernel oil, coconut oil, vegetable oil, safflower oil, canola oil, sunflower oil, or a combination comprising at least one of the foregoing. The crude fatty acid product can comprise impurities. The impurities can comprise unsplit or incompletely split glycerides, color bodies, steroid alcohols, phosphatides, or a combination comprising at least one of the foregoing.

[0024] The unsplit or incompletely split glycerides can comprise a monoglyceride, a diglyceride, or a combination comprising at least one of the foregoing. The monoglyceride, diglyceride, or a combination comprising at least one of the foregoing can be converted to a triglyceride.

[0025] The short chain fatty acid stream can comprise C6-10 fatty acids, for example, the short chain fatty acid stream can comprise C _6-8 fatty acids or Cs-io fatty acids.

[0026] The acid chloride can comprise a fatty acid chloride, for example, the fatty acid chloride can comprise caproic chloride, capric chloride, pelargonic chloride, caprylic chloride, lauric chloride, myristic chloride, palmitic chloride, isopalmitic chloride, stearic chloride, isostearic chloride, oleic chloride, or a combination comprising at least one of the foregoing.

[0027] The free fatty acid can be distilled under vacuum, for example, at a pressure of 1 kPa to 16 kPa.

[0028] At least 95 wt% of the free fatty acid can be recovered from the short chain fatty acid stream, for example, at least 98 wt%, for example, at least 99 wt%.

[0029] The triglyceride converted from the monoglyceride, diglyceride, or a combination comprising at least one of the foregoing can be recycled to the splitting column.

EXAMPLE

Example 1

[0030] To a three-necked, round-bottomed flask equipped with reflux condenser, a calcium chloride guard tube with a nitrogen inlet and a magnetic stirrer was charged with crude Cs/Cio (50:50) fatty acid (100 grams (g)) and distilled in the presence of boric acid (0.008 g) at a temperature of 30°C to 100°C for 15 to 30 minutes to form free fatty acids.

The free fatty acids were then distilled under vacuum at a pressure of 1 kPa to 16 kPa to obtain purified free fatty acid with very low amounts of residual impurities as shown in Table 1.

[0031] Table 2 lists the color value results of samples treated with no boric acid (Sample 1), with 100 ppm boric acid (Sample 2), and with 50 ppm boric acid (Sample 3), in accordance with ASTM D1209-05. This is also referred to as the“Hazen” value. As shown, Samples 2 and 3 treated with boric acid have improved color values (i.e., decreased discoloration) as compared with Sample 1 (no boric acid).

[0032] Table 3 discloses color values before and after heat stability tests were conducted. The color values Y and R were measured based on the LOVIBOND™ RYBN color scale in accordance with AOCS Method Cc 13b-45. The heat stability tests were conducted according to AOCS Method Td 3a-64. Samples 1 and 2 were heated via oil bath. Samples 3 and 4 were heated via heating block. Heat stability was measured for a time of 2 hours at a temperature of 205 °C under nitrogen conditions. As shown, Samples 2 and 4 treated with boric acid have improved color values (i.e., decreased discoloration) and improved heat stability as compared with Samples 1 and 3 (no boric acid).

[0033] After mixing with boric acid, the heat stability and the color value of the fatty acid improved compared to the crude fatty acid.

[0034] This disclosure further encompasses the following aspects.

[0035] Aspect 1: A process for preparing fatty acids, comprising: forming a crude fatty acid product by splitting a feedstream comprising oils and/or fats in a splitting column; fractioning the crude fatty acid product into a short chain fatty acid stream, a long chain fatty acid stream, and a residual product stream in a fractionating distillation column; mixing the short chain fatty acid stream with a whitening compound during distillation in a first distillation column, forming an intermediate short chain fatty acid stream; and purifying the intermediate short chain fatty acid stream by distilling the intermediate short chain fatty acid in a second distillation column, forming a free fatty acid; wherein impurities and unmixed whitening compound is removed from the intermediate short chain fatty acid in the residual product stream.

[0036] Aspect 2: The process of Aspect 1, wherein the feedstream comprises palm kernel oil, coconut oil, vegetable oil, safflower oil, canola oil, sunflower oil, or a combination comprising at least one of the foregoing. [0037] Aspect 3: The process of Aspect 1 or Aspect 2, wherein the crude fatty acid product comprises impurities.

[0038] Aspect 4: The process of Aspect 3, wherein the impurities comprise unsplit or incompletely split glycerides, color bodies, steroid alcohols, phosphatides, quinindoline, amines, nitriles, metal complexes, or a combination comprising at least one of the foregoing, preferably wherein the color bodies comprise at least one of tocopherols or pigments, more preferably , wherein the color bodies comprise at least one of chlorophylls or carotenoids.

[0039] Aspect 5: The process of Aspect 4, wherein the unsplit or incompletely split glycerides comprise a monoglyceride, a diglyceride, or a combination comprising at least one of the foregoing.

[0040] Aspect 6: The process of Aspect 5, wherein the monoglyceride, diglyceride, or a combination comprising at least one of the foregoing is converted to a triglyceride.

[0041] Aspect 7: The process of any of the preceding aspects, wherein the short chain fatty acid stream comprises C _6-i o fatty acids, preferably, wherein the short chain fatty acid stream comprises Ce-Cs fatty acids or Cs-io fatty acids.

[0042] Aspect 8: The process of any of the preceding aspects, wherein the whitening compound comprises boric acid, phosphoric acid, an alkyl derivative of phosphoric acid, or a combination comprising at least one of the foregoing, preferably wherein the whitening compound comprises boric acid.

[0043] Aspect 9: The process of any of the preceding aspects, further comprising distilling the free fatty acid under vacuum.

[0044] Aspect 10: The process of Aspect 9, wherein the vacuum pressure is 1 kPa to

16 kPa.

[0045] Aspect 11: The process of any of the preceding aspects, wherein mixing of the intermediate short chain fatty acid stream with the whitening agent occurs at a temperature of 25°C to 125°C, preferably, 30°C to 100°C, for 15 to 30 minutes.

[0046] Aspect 12: The process of any of the preceding aspects, wherein the whitening compound is present in an amount of 50 ppm to 1000 ppm, based on the weight of the intermediate short chain fatty acid stream.

[0047] Aspect 13: The process of any of the preceding aspects, wherein the free fatty acid contains less than or equal to 1.0 ppm of the whitening compound, preferably, less than or equal to 0.75 ppm, more preferably, less than or equal to 0.5 ppm, based on the weight of the free fatty acid. [0048] Aspect 14: The process of any of the preceding aspects, wherein a color value of the free fatty acid is less than or equal to 65, preferably, less than or equal to 55, preferably, less than or equal to 50 as measured according to APHA COLOR System in accordance with ASTM D1209-05.

[0049] Aspect 15: The process of any of the preceding aspects, wherein at least 95 wt% of free fatty acid are recovered from the intermediate short chain fatty acid stream, preferably, at least 98 wt%, more preferably, at least 99 wt%.

[0050] Aspect 16: The process of any of the preceding aspects, wherein the whitening agent is present in an amount of 75 ppm to 700 ppm, preferably 80 ppm to 500 ppm, or 80 ppm to 300 ppm, based on the weight of the intermediate short chain fatty acid stream.

[0051] As described herein, the terms“crude fatty acids” and“crude fatty acid product” refer to free fatty acids that are contaminated with one or more of the impurities described herein. Examples of impurities include unsplit or incompletely split glycerides (like monoglycerides, diglycerides, or a combination comprising at least one of the foregoing), color bodies, steroid alcohols, and phosphatides.

[0052] The compositions, methods, and articles can alternatively comprise, consist of, or consist essentially of, any appropriate materials, steps, or components herein disclosed.

The compositions, methods, and articles can additionally, or alternatively, be formulated so as to be devoid, or substantially free, of any materials (or species), steps, or components, that are otherwise not necessary to the achievement of the function or objectives of the

compositions, methods, and articles.

[0053] All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other (e.g., ranges of“up to 25 wt%, or, more specifically, 5 wt% to 20 wt%”, is inclusive of the endpoints and all intermediate values of the ranges of“5 wt% to 25 wt%,” etc.). “The terms“first,”“second,” and the like, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The terms“a” and“an” and“the” do not denote a limitation of quantity, and are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. “Or” means“and/or” unless clearly stated otherwise.

Reference throughout the specification to“an embodiment” means that a particular element described in connection with the embodiment is included in at least one embodiment described herein, and may or may not be present in other embodiments. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various embodiments. [0054] As used herein, the phrases“free fatty acids” and“fatty acids” refer to aliphatic monocarboxylic acids having varying degrees of unsaturation and that are derivable from glycerides (the esters of glycerol with the aliphatic monocarboxylic acids).

[0055] Unless defined otherwise, technical and scientific terms used herein have the same meaning as is commonly understood by one of skill in the art to which this application belongs. All cited patents, patent applications, and other references are incorporated herein by reference in their entirety. However, if a term in the present application contradicts or conflicts with a term in the incorporated reference, the term from the present application takes precedence over the conflicting term from the incorporated reference.

[0056] All test standards and methods, such as ASTM, AOCS, and ISO, are the most recent standard as of November 20, 2018, unless specified otherwise

[0057] While particular embodiments have been described, alternatives,

modifications, variations, improvements, and substantial equivalents that are or may be presently unforeseen may arise to applicants or others skilled in the art. Accordingly, the appended claims as filed and as they may be amended are intended to embrace all such alternatives, modifications variations, improvements, and substantial equivalents.