Use of silica-zirconia catalysts in processes for reducing glycidol, glycidyl esters or both glycidol and glycidyl esters

Abstract

The present invention discloses a method of using a silica-zirconia catalyst in a method for reducing the amount of glycidol, glycidyl esters or both glycidol and glycidyl esters from triglyceride-containing compositions such as edible oils. The present invention also discloses a silica-zirconia catalyst and a method for preparing the silica-zirconia catalyst.

Description

Technical Field

[0001] The present invention relates to a method of using a silica-zirconia catalyst in a process for reducing the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in a triglyceride-containing composition. The present invention also relates to a silica-zirconia catalyst and a method for preparing the silica-zirconia catalyst. Background Art

[0002] Glycidyl esters are known carcinogens and mutagens present in processed edible oils. These thermally generated contaminants form at temperatures as low as 200 °C; however, much higher temperatures are required during the deodorization process to remove the various volatile components in the oil. After crude oil undergoes primary refining, bleaching, and deodorization (RBD), additional oil processing is required to reduce the glycidyl ester concentration to acceptable regulatory limits. These reduction methods include various process combinations, including but not limited to contacting the oil with enzymes, shear mixing the oil with an acid, re-bleaching the oil, and / or deodorizing at a lower temperature for a longer period of time. These known methods are not only inefficient and operationally costly, but also further degrade the oil quality and reduce the market price.

[0003] There remains a need in the art for an effective method for reducing thermally generated contaminants, such as glycidyl esters, from triglyceride-containing compositions, such as edible oils. Summary of the Invention

[0004] The present invention addresses the above need in the art by discovering a method for reducing the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in a triglyceride-containing composition, wherein the method provides an effective and environmentally friendly method without the drawbacks of previously known methods. Advantageously, the method of the present invention (1) requires much lower processing temperatures, (2) requires shorter processing times, (3) does not increase the free fatty acid content of the edible oil, and (4) does not cause any significant oxidation, as measured by the p-anisidine value and / or peroxide value of the treated triglyceride-containing composition (e.g., treated edible oil).

[0005] Accordingly, the present invention provides a method for reducing the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in a triglyceride-containing composition. In some embodiments, the method for reducing the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in a triglyceride-containing composition comprises contacting the triglyceride-containing composition with an effective amount of a silica-zirconia catalyst to reduce the amount of (i) glycidol, (ii) glycidyl esters, or (iii) both glycidol and glycidyl esters in the composition, wherein the amount of (i) glycidol, (ii) glycidyl esters, or (iii) both glycidol and glycidyl esters is reduced without affecting other components of the triglyceride-containing composition (i.e., without increasing the free fatty acid content of the triglyceride-containing composition and without any significant oxidation of the triglyceride-containing composition, as measured by the p-anisidine value and / or peroxide value of the treated triglyceride-containing composition).

[0006] In some embodiments, the method advantageously uses a relatively short reaction time (e.g., less than or up to 60 minutes) and a relatively low reaction temperature (e.g., generally from room temperature up to about 100 °C). The method may also include heating the triglyceride-containing composition and the silica-zirconia particles in order to more effectively reduce glycidol, glycidyl esters, or both glycidol and glycidyl esters using the disclosed silica-zirconia catalyst. Unexpectedly, it has been found that incorporation of an effective amount of the disclosed silica-zirconia catalyst particles provides excellent catalytic activity in reducing glycidol, glycidyl esters, or both glycidol and glycidyl esters present in a triglyceride-containing composition (e.g., edible oil).

[0007] In some desired embodiments, the method for reducing the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in an edible oil containing triglycerides advantageously provides an edible oil having a low level (i.e., less than 0.2 ppm) of glycidyl esters and with little or no change in (i) the initial free fatty acid content of the edible oil (as measured by oleic acid content) or (ii) the initial lipid oxidation level of the edible oil, as measured by (a) the p-anisidine value of the edible oil as measured by the American Oil Chemists' Society (AOCS) official method Cd 18-90, (b) the peroxide value of the edible oil as measured by the AOCS official method Cd 8-53, or (c) both (a) and (b).

[0008] The present invention also relates to a silica-zirconia catalyst for use in a method of reducing the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in a triglyceride-containing composition as disclosed herein. The silica-zirconia catalyst comprises porous silica particles impregnated with zirconia. In some embodiments, the zirconia is impregnated onto at least a portion of the surface of the porous silica particles. In some embodiments, the zirconia is impregnated into at least a portion of the pores of the porous silica particles. In some embodiments, the zirconia is impregnated such that it is substantially located within the pores of the porous silica particles. Generally, the silica-zirconia particulate catalyst comprises at least 0.01 weight percent (wt%) zirconia based on the total weight of the silica-zirconia particles. More typically, the silica-zirconia particulate catalyst comprises from about 1.0 wt% to about 50.0 wt% zirconia based on the total weight of the catalyst.

[0009] The present invention also relates to a method of preparing the silica-zirconia particulate catalyst disclosed herein. In some embodiments, the method of preparing the silica-zirconia catalyst comprises: impregnating porous silica particles with a solution of zirconium acetate in acetic acid and water; drying the impregnated porous silica particles at a temperature sufficient to dry the impregnated porous silica particles for a period of time, i.e., drying at about 80 °C to about 150 °C for about 1 hour to about 4 hours; and calcining the dried zirconia-impregnated porous silica particles at a temperature in the range of about 400 °C to about 1000 °C for about 2 hours to about 8 hours.

[0010] The present invention also relates to a composition comprising (i) a triglyceride-containing composition and (ii) the silica-zirconia particulate catalyst disclosed herein. In some embodiments, the composition comprises (i) an oil and (ii) the silica-zirconia catalyst disclosed herein. The composition may also comprise glycidol, glycidyl esters, or both glycidol and glycidyl esters (i.e., the composition prior to being subjected to the method of reducing the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters as disclosed herein), or may have a minimal or negligible amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters (i.e., the composition after being subjected to the method of reducing the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters as disclosed herein). In some desirable embodiments, the triglyceride-containing composition is an oil, specifically, an edible oil such as soybean oil or palm oil.

[0011] These and other features and advantages of the present invention will become apparent after reading the following detailed description of the disclosed embodiments and the appended claims. DETAILED DESCRIPTION

[0012] To facilitate an understanding of the principles of the present invention, the following is a description of specific embodiments of the present invention, and the specific embodiments are described in specific language. However, it should be understood that the use of specific language is not intended to limit the scope of the present invention. Changes, further modifications, and such further applications of the principles of the present invention discussed are considered to be commonly contemplated by those of ordinary skill in the art to which the present invention pertains.

[0013] It must be noted that, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" as used herein and in the appended claims include plural referents. Thus, for example, reference to "an oxide" includes multiple such oxides, and reference to "oxide" includes reference to one or more oxides and their equivalents known to those skilled in the art, etc.

[0014] As used herein, the modifier "about" in describing amounts, concentrations, volumes, process temperatures, process times, recovery rates or yields, flow rates, and similar values, as well as their ranges, employed in the embodiments of the present disclosure, such as coated particles and / or components of a composition, refers to variations in the numerical quantity that can occur, for example, by: typical measurement and processing procedures; errors resulting from negligence in these procedures; differences in the components used to carry out the method; and similar considerations. The term "about" also encompasses amounts that differ due to the aging of a formulation having a particular initial concentration or mixture, and amounts that differ due to mixing or processing a formulation having a particular initial concentration or mixture. Whether or not modified by the term "about", the appended claims herein include equivalents.

[0015] As used herein, the term "triglyceride-containing composition" (also referred to herein as "composition comprising triglyceride") preferably refers to any liquid comprising one or more triglycerides and optionally one or more additional composition components. In some embodiments of the present invention, glycidol, glycidyl esters, or both glycidol and glycidyl esters are present in edible oils such as soybean oil.

[0016] As used herein, the term "crystal" refers to a solid material whose constituent atoms, molecules, or ions are arranged in an ordered pattern extending in all three directions, which can be measured by X-ray diffraction or differential scanning calorimetry. As used herein, the term "amorphous" refers to a solid material whose constituent atoms, molecules, or ions are arranged in a random disordered pattern extending in all three directions, which can be determined by X-ray diffraction or differential scanning calorimetry.

[0017] As used herein, the term "BET particle surface area" is defined to refer to the particle surface area measured by the Brunauer Emmet Teller (BET) nitrogen adsorption method.

[0018] As used herein, the phrase "total pore volume" refers to the average pore volume of a plurality of particles (e.g., the silica-zirconia particles disclosed herein) as determined using the Barrett-Joyner-Halenda (BJH) nitrogen porosimetry method as described in DIN 66134.

[0019] As used herein, the phrase "particle size" refers to the median particle size (D50, which is the volume distribution where 50 volume % of the particles are smaller in size and 50 volume % of the particles are larger in size than this number) measured by dynamic light scattering when the particles are slurried in water or an organic solvent such as acetone or ethanol.

[0020] Method using silica-zirconia catalyst

[0021] The present invention relates to a method for reducing the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in a triglyceride-containing composition. The method can include, for example, contacting the triglyceride-containing composition with an effective amount of a silica-zirconia catalyst at a temperature sufficient to reduce the amount of glycidol, glycidyl esters, or both for a period of time. The method can also include mixing the triglyceride-containing composition with the silica-zirconia catalyst under vacuum or an inert gas, optionally with heating. The method generally reduces the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in a given triglyceride-containing composition by at least 50 weight percent (wt %), while utilizing relatively low reaction times and temperatures. For example, at a reaction temperature of less than about 100 °C, the reaction time and temperature can be as low as 60 minutes.

[0022] In some embodiments, the disclosed method for reducing the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in a triglyceride-containing composition includes contacting the triglyceride-containing composition with an effective amount of a catalyst at room temperature, but other temperatures can also be used (e.g., preferably, from room temperature, i.e., about 20 °C - 25 °C up to about 90.0 °C).

[0023] Generally, when used in the disclosed method, the heating step includes heating the triglyceride-containing composition and the silica-zirconia catalyst to a temperature of at least about 40.0 °C. In some embodiments, when used in the disclosed method, the heating step includes heating the triglyceride-containing composition and the silica-zirconia catalyst to a temperature of about 90.0 °C. Generally, the heating step includes heating the triglyceride-containing composition and the silica-zirconia catalyst to a temperature between about 20.0 °C and about 90.0 °C (or any temperature range between about 20.0 °C and about 90.0 °C in increments of 0.1 °C, e.g., about 20.1 °C to about 89.9 °C).

[0024] Regardless of the highest temperature reached during the optional heating step (e.g., about 90.0 °C), when used, the heating step advantageously includes heating the triglyceride-containing composition and the silica-zirconia catalyst to a temperature of about 90.0 °C; and maintaining the temperature for at least 10.0 minutes. In some embodiments, the heating step includes heating the triglyceride-containing composition and the silica-zirconia catalyst to the highest temperature (e.g., about 90.0 °C); and maintaining the highest temperature for about 30.0 minutes. It should be understood that in the disclosed method, the highest temperature of the optional heating step (e.g., about 90.0 °C) can be maintained at the highest temperature (e.g., about 90.0 °C) for any desired amount of time, e.g., about 5.0 minutes to about 60.0 minutes (or any range of minutes between about 5.0 minutes and about 60.0 minutes in 0.1-minute increments, e.g., about 5.1 minutes to about 59.9 minutes).

[0025] Advantageously, when used in the disclosed method, the heating step includes heating the triglyceride-containing composition and the silica-zirconia catalyst under the following conditions: (i) under a stream of inert gas (i.e., under a layer of inert gas), (ii) under vacuum, or (iii) both (i) under a stream of inert gas and (ii) under vacuum. Generally, the inert gas (when used) includes nitrogen, argon, carbon dioxide, or any combination thereof.

[0026] The disclosed method for reducing the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in a triglyceride-containing composition is particularly useful when the triglyceride-containing composition includes (i) a triglyceride-based oil, (ii) an organic solvent capable of dissolving triglycerides, or (iii) both a triglyceride-based oil and an organic solvent capable of dissolving triglycerides. Suitable oils include, but are not limited to, soybean oil, palm oil, corn oil, canola oil, rapeseed oil, fish oil, algal oil, sunflower oil, olive oil, vegetable oil, plant-derived oil, animal-derived oil, microbe-derived oil, or any combination thereof. Suitable organic solvents include, but are not limited to, heptane, hexane, toluene, diethyl ether, alcohol, or any combination thereof.

[0027] In some desirable embodiments, the disclosed method for reducing the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in a triglyceride-containing composition is particularly useful when the triglyceride-containing composition includes an edible oil (such as soybean oil or palm oil).

[0028] Generally, the disclosed methods for reducing the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in triglyceride-containing compositions include using an effective amount of a silica-zirconia catalyst, which is at least about 0.01 wt% based on the total weight of the silica-zirconia catalyst and the triglyceride-containing composition. In some embodiments, the amount of the silica-zirconia catalyst used in the disclosed methods is about 0.5 wt% to about 10.0 wt% of the silica-zirconia catalyst based on the total weight of the silica-zirconia catalyst and the triglyceride-containing composition. In other embodiments, the amount of the silica-zirconia catalyst used in the disclosed methods is about 1.0 wt% to about 3.0 wt% of the silica-zirconia catalyst based on the total weight of the silica-zirconia catalyst and the triglyceride-containing composition. However, it should be understood that any amount of the silica-zirconia catalyst can be used in the disclosed methods for reducing the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in triglyceride-containing compositions, e.g., any amount from about 0.5 wt% to about 10.0 wt% (or any weight percentage range between about 0.5 wt% and about 10.0 wt% in 0.1 wt% increments, e.g., about 0.6 wt% to about 9.9 wt%) of the silica-zirconia catalyst based on the total weight of the silica-zirconia catalyst and the triglyceride-containing composition.

[0029] Surprisingly, it has been determined that the disclosed method for reducing the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in a triglyceride-containing composition is capable of reducing the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in the triglyceride-containing composition to a level of less than about 10.0 parts per million (ppm). In some embodiments, the disclosed method is capable of reducing the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in the triglyceride-containing composition to a level of less than about 5.0 ppm. In other embodiments, the disclosed method is capable of reducing the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in the triglyceride-containing composition to a level of less than about 1.0 ppm. In other embodiments, the disclosed method is capable of reducing the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in the triglyceride-containing composition to a level of less than about 0.5 ppm. In other embodiments, the disclosed method is capable of reducing the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in the triglyceride-containing composition to a level of less than about 0.2 ppm.

[0030] Surprisingly, it has been determined that the disclosed method for reducing the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in a triglyceride-containing composition is capable of reducing at least 50 weight percent (wt%) of the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in the triglyceride-containing composition within the above reaction parameters (i.e., reaction temperature from room temperature to less than about 100 °C, and / or reaction time up to about 60 minutes). In some embodiments, the method reduces at least 80.00 wt% of the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in the triglyceride-containing composition. In some embodiments, the disclosed method is capable of reducing up to about 99.99 wt% (or any weight percentage range between about 50.00 wt% and 99.99 wt% in 0.01 wt% increments, e.g., about 50.01 wt% to 99.98 wt%) of the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in the triglyceride-containing composition within the above reaction parameters (i.e., reaction temperature from room temperature to less than about 100 °C, and / or reaction time up to about 60 minutes).

[0031] Furthermore, and unexpectedly, the disclosed methods for reducing the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in triglyceride-containing compositions are capable of reducing the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters to extremely low levels without adversely affecting the free fatty acid content of a given triglyceride-containing composition. In some embodiments, a given triglyceride-containing composition (e.g., soybean oil or palm oil) has a free fatty acid content prior to contact with the silica-zirconia catalyst of the present invention, and the disclosed methods, which particularly include contacting the triglyceride-containing composition (e.g., soybean oil or palm oil) with the silica-zirconia catalyst, negligibly alter the free fatty acid content of the triglyceride-containing composition (i.e., as oleic acid) as measured by the AOCS official method Ca 5a-40.

[0032] In some desired embodiments of the present invention, the method for reducing the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in a triglyceride-containing composition includes a method for preparing an edible oil in which the level of glycidol and / or glycidyl esters is less than 0.2 ppm and in which the following are little to not changed: (i) the free fatty acid content of the edible oil (i.e., as oleic acid) and / or (ii) the oxidation level of the edible oil as measured by: (a) the p-anisidine value of the edible oil as measured, for example, by the AOCS official method Cd 18-90, (b) the peroxide value of the edible oil as measured, for example, by the AOCS official method Cd 8-53, or (c) both (a) and (b).

[0033] In some embodiments, the disclosed method for preparing an edible oil (e.g., in which the level of glycidol and / or glycidyl esters is less than 0.2 ppm) alters the initial free fatty acid content of the edible oil (i.e., as measured by oleic acid content) by less than about 20%. In other embodiments, the disclosed method for preparing an edible oil (e.g., in which the level of glycidol and / or glycidyl esters is less than 0.2 ppm) alters the initial free fatty acid content of the edible oil (i.e., as measured by oleic acid content) by less than about 10%.

[0034] As discussed in AOCS official method Cd 18-90, the full text of which is incorporated herein by reference, the lipid oxidation level of a given edible oil can be measured by the p-anisidine value of the edible oil. The processing of edible oils can result in an undesirable series of chemical reactions involving oxygen, which can reduce the quality of the edible oil. Such undesirable oxidation reactions can generate, for example, primary oxidation products such as peroxides, dienes, free fatty acids, etc., as well as secondary products such as carbonyls, aldehydes, trienes, etc. The p-anisidine value of an edible oil measures the amount of aldehydes in the edible oil.

[0035] In some embodiments, the disclosed method of preparing an edible oil having a glycidol ester level of less than 0.2 ppm changes the initial p-anisidine value of the edible oil by less than about 10.0 units. In other embodiments, the disclosed method of preparing an edible oil having a glycidol ester level of less than 0.2 ppm changes the initial p-anisidine value of the edible oil by less than about 1.0 unit. In other embodiments, the disclosed method of preparing an edible oil having a glycidol ester level of less than 0.2 ppm changes the initial p-anisidine value of the edible oil by less than about 0.2 unit.

[0036] The oxidative level of a given edible oil can also be measured by the peroxide value of the edible oil as measured, for example, by AOCS official method Cd 8-53. As discussed in AOCS official method Cd 8-53, the full text of which is incorporated herein by reference, the peroxide value provides a measure of the amount of peroxides in a given edible oil.

[0037] In some embodiments, the disclosed method of preparing an edible oil having a glycidol ester level of less than 0.2 ppm changes the initial peroxide value of the edible oil by less than about 10.0 units. In other embodiments, the disclosed method of preparing an edible oil having a glycidol ester level of less than 0.2 ppm changes the initial peroxide value of the edible oil by less than about 7.0 units. In other embodiments, the disclosed method of preparing an edible oil having a glycidol ester level of less than 0.2 ppm changes the initial peroxide value of the edible oil by less than about 2.0 units.

[0038] Typically, edible oils are subjected to a refining-bleaching-deodorization (RBD) process. In conventional methods of preparing edible oils, after the RBD process, the edible oil undergoes further processing before use. Further processing of conventionally prepared edible oils (i.e., not treated using the methods described herein) includes, but is not limited to, contacting the oil with enzymes, shear mixing the oil with acids, re-bleaching the oil, and / or deodorizing at a lower temperature for a longer period of time, or any combination of the above processing steps. However, edible oils that have been subjected to the RBD process and are then treated using the disclosed method of preparing an edible oil having a glycidol and / or glycidol ester level of less than 0.2 ppm generally do not require further processing before use (i.e., do not require further processing including, but not limited to, contacting the oil with enzymes, shear mixing the oil with acids, re-bleaching the oil, and / or deodorizing at a lower temperature for a longer period of time, or any combination of the above processing steps).

[0039] Silica-zirconia catalyst for use in the methods described herein

[0040] The silica-zirconia catalyst used in the methods described herein comprises porous silica particles impregnated with zirconia. As described above, in some embodiments, the zirconia is impregnated onto at least a portion of the surface of the porous silica particles. In some embodiments, the zirconia is impregnated into at least a portion of the pores of the porous silica particles. In some embodiments, the zirconia is impregnated such that it is substantially located within the pores of the porous silica particles.

[0041] Suitable porous silica particles for preparing the silica-zirconia catalyst of the present invention include, but are not limited to, silica gel, precipitated silica, pyrogenic silica, and colloidal silica. Suitable porous silica also includes, but is not limited to, ordered mesoporous silica prepared by an organic template (such as a surfactant) during the formation of silica particles, followed by high-temperature treatment to "burn off" the organic matter. Particularly preferred porous silica particles include silica gel particles or precipitated silica particles.

[0042] Any commercially available porous silica particles can be used to form the silica-zirconia catalyst of the present invention. Commercially available porous silica particles that can be used to form the silica-zirconia catalyst of the present invention include, but are not limited to, those sold under the trade name obtained from W.R. Grace (Columbia, MD), such as C807 silica gel particles and MX106 precipitated silica particles, silica particles and silica particles.

[0043] The porous silica particles used to form the silica-zirconia catalyst of the present invention comprise porous silica having a purity of at least about 93.0 wt%, or at least about 93.5 wt%, at least about 94.0 wt%, at least about 95.0 wt%, at least about 96.0 wt%, at least about 97.0 wt%, or at least about 98.0 wt% SiO2, up to 100 wt% SiO2, based on the total weight of the porous silica particles.

[0044] The porous silica particles used to form the silica-zirconia catalyst of the present invention can have a variety of different symmetric, asymmetric, or irregular shapes, including chain, rod, or lath shapes. The porous silica particles can have different structures, including amorphous or crystalline, etc. In a preferred embodiment, the porous silica particles are amorphous. The porous silica particles can include a mixture of particles having different compositions, sizes, shapes, or physical structures, or can be the same except for different surface treatments. In the case where smaller particles agglomerate to form larger particles, the porosity of the porous silica particles can be the porosity within or between the particles.

[0045] Generally, the silica-zirconia catalyst (and independently the porous silica particles used to form the silica-zirconia particles) has a median particle size of from about 0.1 micrometers (μm) to about 10,000 μm (or any median particle size range between about 0.1 μm and about 10,000 μm in 0.1 μm increments, such as from about 0.2 μm to about 9,999.9 μm). In some embodiments, the silica-zirconia particles used in the methods described herein (and independently the porous silica particles used to form the silica-zirconia particles) have a median particle size of from about 80.0 μm to about 400 μm. In some embodiments, the silica-zirconia particles used in the methods described herein (and independently the porous silica particles used to form the silica-zirconia particles) have a median particle size of from about 100.0 μm to about 200 μm.

[0046] The silica-zirconia catalysts (and, independently, the porous silica particles used to form the silica-zirconia catalysts) for use in the methods described herein typically have a pore volume of at least 0.01 cubic centimeters per gram (cc / g) as determined by the Barrett-Joyner-Halenda (BJH) method. More typically, the silica-zirconia catalysts (and, independently, the porous silica particles used to form the silica-zirconia catalysts) have a pore volume of at least 0.5 cc / g as determined by the Barrett-Joyner-Halenda (BJH) method. In some embodiments, the silica-zirconia catalysts (and, independently, the porous silica particles used to form the silica-zirconia catalysts) have a pore volume of from about 0.5 cc / g to about 3.0 cc / g or greater as determined by the Barrett-Joyner-Halenda (BJH) method. However, it should be understood that the silica-zirconia catalysts (and, independently, the porous silica particles used to form the silica-zirconia catalysts) for use in the methods described herein can have a pore volume of from about 0.01 cc / g to about 3.00 cc / g (or greater) (or any pore volume range between about 0.01 cc / g and about 3.0 cc / g in 0.01 cc / g increments, such as from about 0.02 cc / g to about 2.99 cc / g) as determined by the Barrett-Joyner-Halenda (BJH) method.

[0047] The silica-zirconia catalysts used in the methods described herein (and, independently, the porous silica particles used to form the silica-zirconia catalysts) may also have a median pore diameter of at least 0.1 nanometers (nm) as determined by mercury intrusion testing procedures using an Autopore IV 9520 available from Micromeritics Instrument Corp. Generally, the silica-zirconia catalysts used in the methods described herein (and, independently, the porous silica particles used to form the silica-zirconia catalysts) have an average pore diameter of from about 1.0 nm to about 1,000.0 nm. In some embodiments, the silica-zirconia catalysts used in the methods described herein (and, independently, the porous silica particles used to form the silica-zirconia catalysts) have an average pore diameter of from about 1.0 nm to about 100.0 nm. In other embodiments, the silica-zirconia catalysts used in the methods described herein (and, independently, the porous silica particles used to form the silica-zirconia catalysts) have an average pore diameter of from about 2.0 nm to about 50.0 nm. However, it should be understood that the silica-zirconia catalysts used in the methods described herein (and, independently, the porous silica particles used to form the silica-zirconia catalysts) can have an average pore diameter in the range of from about 0.1 nm to about 1,000.0 nm (or greater) (or any average pore diameter range between about 0.1 nm and about 1,000.0 nm in 0.1 nm increments, such as from about 0.2 nm to about 999.9 nm).

[0048] The silica-zirconia catalysts used in the methods described herein (and, independently, the porous silica particles used to form the silica-zirconia catalysts) may also have at least about 10 m 2 / g up to about 2,000 m 2 / g or greater BET particle surface area. Generally, the silica-zirconia catalysts used in the methods described herein (and, independently, the porous silica particles used to form the silica-zirconia catalysts) have a BET particle surface area of at least about 25.0 m 2 / g. In some embodiments, the silica-zirconia catalysts (and, independently, the porous silica particles used to form the silica-zirconia catalysts) have a BET particle surface area of at least about 50 m 2 / g up to about 800 m 2 / g. However, it should be understood that the silica-zirconia catalysts used in the methods described herein (and, independently, the porous silica particles used to form the silica-zirconia catalysts) can have from about 10 m 2 / g to about 2,000 m 2 / g (or greater) in the range (or in 0.1 m2 / g is an incremental BET particle surface area value range between about 10 m 2 / g and about 2000 m 2 / g, for example, any BET particle surface area from about 10.1 m 2 / g to about 1999.9 m 2 / g).

[0049] The silica-zirconia catalysts (and independently the porous silica particles used to form the silica-zirconia catalysts) used in the methods described herein are also amenable to size reduction treatment. Any known method for reducing particle size can be used and includes, but is not limited to, grinding steps such as ball milling or mortar and pestle grinding steps.

[0050] The silica-zirconia catalysts (and independently the porous silica particles used to form the silica-zirconia catalysts) used in the methods described herein can comprise a combination of (i) any of the above porous silica particles and (ii) zirconia. As discussed above, zirconia can (i) be impregnated on at least a portion of the particle surface of the porous silica particles, or (ii) be impregnated within at least a portion of the pores of the porous silica particles, or (iii) be impregnated on at least a portion of the surface of the porous silica particles and within at least a portion of the pores of the porous silica particles, or (iv) be substantially impregnated within the pores of the porous silica particles. In one embodiment, zirconia is substantially located within the pores of the silica particles.

[0051] Generally, the silica-zirconia catalysts used in the methods described herein comprise at least about 0.01 weight percent (wt%) of zirconia based on the total weight of the silica-zirconia catalyst. In some embodiments, the silica-zirconia catalysts used in the methods described herein comprise from about 1.0 wt% to about 50.0 wt% of zirconia based on the total weight of the silica-zirconia catalyst. In some desirable embodiments, the silica-zirconia catalysts used in the methods described herein comprise from about 1.5 wt% to about 14.3 wt% of zirconia based on the total weight of the silica-zirconia catalyst. In other desirable embodiments, the silica-zirconia catalysts used in the methods described herein comprise from about 2.4 wt% to about 5.0 wt% of zirconia based on the total weight of the silica-zirconia catalyst. However, it should be understood that the silica-zirconia catalysts used in the methods described herein can comprise any amount of zirconia in the range from about 0.01 wt% to about 50.0 wt% (or greater) (or any amount of zirconia in the range between about 0.01 wt% and about 50.0 wt% in increments of 0.01 wt% based on the total weight of the silica-zirconia catalyst, e.g., from about 0.02 wt% to about 49.99 wt%).

[0052] In some desired embodiments, the silica-zirconia catalyst of the present invention (i) has a median particle size of from about 80.0 μm to about 400 μm; (ii) has a pore volume of from about 0.5 cc / g to about 3.0 cc / g or greater as determined by the Barrett-Joyner-Halenda (BJH) method; (iii) has an average pore diameter of from about 1.0 nm to about 100.0 nm; (iv) has a BET particle surface area of at least about 50.0 m 2 / g up to about 800 m 2 / g; and (v) contains from about 1.0 wt% to about 50.0 wt% of zirconia based on the total weight of the silica-zirconia catalyst.

[0053] In other desired embodiments, the silica-zirconia catalyst of the present invention (i) has a median particle size of from about 100.0 μm to about 200 μm; (ii) has a pore volume of from about 1.0 cc / g to about 2.0 cc / g as determined by the Barrett-Joyner-Halenda (BJH) method; (iii) has an average pore diameter of from about 15.0 nm to about 30.0 nm; (iv) has a BET particle surface area of at least about 75.0 m 2 / g up to about 400 m 2 / g; and (v) contains from about 2.5 wt% to about 15.0 wt% of zirconia based on the total weight of the silica-zirconia catalyst.

[0054] Method for preparing a silica-zirconia catalyst for use in the methods described herein

[0055] The silica-zirconia catalyst for use in the methods described herein can be formed by a zirconia coating and / or impregnation step, followed by one or more additional steps such as a drying step, a calcination step, or both. In some embodiments, a method of preparing a silica-zirconia catalyst suitable for use in the methods described herein includes impregnating porous silica particles with a solution of zirconium acetate in acetic acid and water; drying the impregnated porous silica particles at about 105 °C for about 2 hours; and calcining the dried impregnated porous silica particles at about 500 °C for about 4 hours.

[0056] Generally, a method of preparing a silica-zirconia catalyst includes an impregnation step that allows for a period of time sufficient for contact between the porous silica particles and zirconium acetate. In some embodiments, the impregnation step allows for a period of contact between the porous silica particles and zirconium acetate of about 30 minutes. However, it should be understood that the impregnation step can allow for any desired period of contact between the porous silica particles and zirconium acetate.

[0057] In some desired embodiments, after the impregnation step and before the drying step, a method of preparing a silica-zirconia catalyst comprises grinding the impregnated porous silica particles for about 60 minutes. It should be understood that the impregnated porous silica particles can be ground (or are ground) for any desired period of time.

[0058] Composition for use in the methods described herein and prepared by the methods described herein

[0059] The present invention also relates to a triglyceride-containing composition comprising the silica-zirconia catalyst described herein. As discussed above, generally, a given triglyceride-containing composition (i.e., before or after the above-described method for reducing the amount of glycidol, glycidyl esters or both glycidol and glycidyl esters in a triglyceride-containing composition and / or the method for preparing an edible oil, before removing the silica-zirconia catalyst) comprises greater than about 0.01% by weight, typically from about 0.50% to about 10.0% by weight (or any weight percentage range between about 0.50% and about 10.00% by weight in increments of 0.01% by weight, e.g., from about 1.00% to about 3.00% by weight) of the silica-zirconia catalyst described herein, based on the total weight of the silica-zirconia catalyst and the triglyceride-containing composition. As discussed above, in some desired embodiments, the triglyceride-containing composition of the present invention comprises the silica-zirconia catalyst described herein in an oil (e.g., an edible oil such as soybean oil or palm oil) or an organic solvent (e.g., a triglyceride-dissolving solvent such as toluene) (i.e., before or after the above-described method for reducing the amount of glycidol, glycidyl esters or both glycidol and glycidyl esters in a triglyceride-containing composition and / or the method for preparing an edible oil, before removing the silica-zirconia catalyst). In some desired embodiments, the triglyceride-containing composition of the present invention comprises the silica-zirconia catalyst described herein in an edible oil (e.g., soybean oil or palm oil) (i.e., before or after the above-described method for reducing the amount of glycidol, glycidyl esters or both glycidol and glycidyl esters in a triglyceride-containing composition and / or the method for preparing an edible oil, before removing the silica-zirconia catalyst).

[0060] The present invention also relates to an oil and a triglyceride-containing composition obtained by the above-described method for reducing the amount of glycidol, glycidyl esters or both glycidol and glycidyl esters in a triglyceride-containing composition and / or the method for preparing an edible oil, before or after removing the silica-zirconia catalyst. In some desired embodiments, the disclosed method is used to prepare an edible oil.

[0061] It should be understood that although the above silica-zirconia catalysts, methods and uses are described as "comprising" one or more components or steps, the above silica-zirconia catalysts, methods and uses may "comprise" any of the above components or steps of the silica-zirconia catalysts, methods and uses or "consist of" or "consist essentially of" them. Thus, in cases where open-ended terms such as "comprising" are used to describe the present invention or a part thereof, it should be readily understood (unless otherwise specified) that the description of the present invention or a part thereof should also be construed as describing the present invention or a part thereof using terms such as "consisting essentially of" or "consisting of" or their variants as described hereinafter.

[0062] As used herein, the terms "comprising", "containing", "including", "having", "characterized by" or any other variants thereof are intended to cover non-exclusive inclusion of the recited components without any additional expressly specified limitation. For example, a silica-zirconia catalyst, method and / or use "comprising" a list of elements (e.g., components or steps) is not necessarily limited to those elements (or components or steps), but may also include other elements (or components or steps) not expressly listed or inherent to the silica-zirconia catalyst, method and / or use.

[0063] As used herein, the transitional phrases "consisting of" and "composed of" exclude any element, step or component not specified. For example, "consisting of" or "composed of" as used in a claim limits the claim to the components, materials or steps specifically recited in the claim, except for impurities normally associated therewith (i.e., impurities within a given component). When the phrase "consisting of" appears in a clause of a claim item, rather than immediately following the preamble, the phrase "consisting of" only limits the elements (or components or steps) set forth in that clause; other elements (or components) are not excluded from the claim as a whole.

[0064] As used herein, the transitional phrase "consisting essentially of" is used to define a silica-zirconia catalyst, method and / or use that includes materials, steps, features, components or elements in addition to those literally disclosed, provided that these additional materials, steps, features, components or elements do not materially affect one or more of the basic and novel characteristics of the claimed invention. The term "consisting essentially of" lies in the intermediate ground between "comprising" and "consisting of".

[0065] The following examples further illustrate the present invention and are not to be construed in any way as imposing limitations on the scope of the present invention. On the contrary, it will be clearly understood that various other embodiments, modifications, and their equivalents can be contemplated by those skilled in the art after reading the present specification, without departing from the spirit and / or scope of the appended claims.

[0066] Examples

[0067] The following examples describe (i) a method for preparing a silica - zirconia catalyst according to the present invention, and (ii) an evaluation of the silica - zirconia catalyst in reducing the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in various triglyceride - containing compositions.

[0068] Nitrogen pore volume and BET surface area measurements of silica-zirconia particle samples

[0069] The nitrogen pore volume of the silica - zirconia catalyst was measured using an iQ analyzer purchased from Quantachrome Instrument (Boynton Beach, FL). Degassing of each sample was carried out at 65 °C (i.e., below the wax melting temperature of about 80 °C) for 4 hours. Nitrogen adsorption and desorption isotherms were measured at 77 K, where the nitrogen pressure was increased from 0.01% atmosphere to 0.998% atmosphere and then decreased from 0.998% atmosphere to 0.025% atmosphere. The pore volume was calculated using the ASIQWIN TM version 5.0 program based on the BJH theory. See, for example, Barrett et al., The Determination of PoreVolume and Area Distributions in Porous Substances.I.Computations fromNitrogen Isotherms, J Am Chem Soc ..1951, Vol. 73, No. 1, pp. 373 - 380, and the BET surface area was also calculated based on the Brunauer Emmet Teller method (Brunauer et al., “Adsorption of Gases inMultimolecular Layers”. J.Am Chem Soc ..1938, 60(2): 309 - 319), the subject matter of both documents is incorporated herein by reference in its entirety.

[0070] Total glycidol concentration analysis

[0071] The total glycidol concentration of a given sample is determined using the AOCS official method Cd 29c-13, the subject matter of which is hereby incorporated by reference in its entirety. This method determines the concentration of the sum of (i) total free glycidol and (ii) bound glycidol (i.e., glycidyl esters) present in a given sample.

[0072] Catalyst synthesis

[0073] Porous silica-zirconia catalyst particles are prepared using the following procedure. A desired amount of zirconium acetate is diluted with water in acetic acid and used to impregnate the porous silica particles over a 30-minute period, followed by an additional hour of grinding. The material is then dried at 105 °C for 2 hours and then calcined at 500 °C for 4 hours.

[0074] The resulting silica-zirconia catalyst has a zirconia concentration in the range of 0.01 wt% to 49.99 wt%. As further discussed below, in some embodiments, silica-zirconia catalysts having a zirconia concentration in the range of about 2.00 wt% to about 20.00 wt% provide effective results. The final zirconia concentration is determined using ICP elemental trace analysis.

[0075] Four sample silica-zirconia catalysts, namely catalysts A to D, are formed using the synthesis procedures described herein. The characteristics of catalysts A to D are shown in Table 1 below.

[0076] Table 1. Characteristics of sample catalysts A to D

[0077]

[0078] Reaction process

[0079] Each oil / solvent is loaded into a round-bottom flask and admixed with glycidol and / or glycidyl esters (e.g., glycidyl oleate). The overhead stirrer is set to 250 rpm. The reactor is purged with an inert gas and then an initial sample is taken for GC / MS analysis. The required catalytic amount of the silica-zirconia catalyst is added and then the temperature is raised to the desired set point. After the required amount of time, a final sample is taken and then filtered through a filter disc to remove the solid catalyst before analysis.

[0080] The reaction temperature is not limited, but is preferably from about 45 °C to about 90 °C. With respect to the edible oil industry, maintaining the temperature below 90 °C helps to prevent oil oxidation, but allows the reduction of glycidol and glycidyl esters over a sufficient amount of time. Similarly, the reaction time is not limited, but is preferably less than 2 hours to minimize the residence time in the refiner.

[0081] Example 1 - Control experiment

[0082] The above reaction process is used in the following examples. Soybean oil doped with glycidyl oleate was mixed and heated to a maximum temperature of 90 °C under argon. As shown in Table 2 below, the total glycidyl concentration in the reaction mixture was measured within 30 minutes.

[0083] Table 2. Results of control experiment

[0084] Reaction time Glycidol (ppm) Doped soybean oil 22.35 Heated to 90 °C 22.58 15 minutes 24.56 30 minutes 23.12

[0085] As shown in Table 2, in the absence of a catalyst added to the reaction mixture, there was no reduction of glycidyl / glycidyl oleate.

[0086] Example 2 - Dosage effect of silica-zirconia catalyst entering the reaction mixture

[0087] The above catalyst synthesis and reaction methods are used in the following examples. The catalyst A of the present invention was added to soybean oil doped with glycidyl oleate at 0.5 wt%, 1.0 wt%, 1.5 wt% and 2.0 wt% based on the total weight of the silica-zirconia catalyst and soybean oil. The reaction mixture was mixed and heated to a maximum temperature of 90 °C under argon. As shown in Table 3 below, the concentration of total glycidyl in the reaction mixture was measured before and after 30 minutes.

[0088] Table 3. Epoxide reduction at various catalyst dosages

[0089] Catalyst dosage weight % Initial glycidol (ppm) Final glycidol (ppm) 0.5 9.79 1.62 1.0 10.24 <LOQ 1.5 10.38 <LOQ 2.0 17.90 <LOQ

[0090] Limit of Quantitation (LOQ) = 0.20 ppm

[0091] As shown in Table 3, a dose of as little as 0.5 wt% of the silica-zirconia catalyst significantly reduced glycidyl / glycidyl oleate at 90 °C within 30 minutes. Similarly, increasing the dose of the silica-zirconia catalyst improved the reduction of glycidyl / glycidyl oleate in the reaction mixture within a set amount of time.

[0092] Example 3 - Zirconia concentration and its effect on total glycidol reduction

[0093] The above catalyst synthesis and reaction methods are used in the following examples. The catalysts A, B, C and D of the present invention were added to soybean oil doped with glycidyl oleate. A silica / zirconia catalyst based on 2.0 wt% of the total weight of the catalyst and soybean oil was used. The reaction mixture was mixed and heated to a maximum temperature of 90 °C under argon. As shown in Table 4 below, the concentration of total glycidyl in the reaction mixture was measured before and after 30 minutes.

[0094] Table 4. Glycidol reduction at various zirconia concentrations

[0095] Catalyst Initial glycidol (ppm) Final glycidol (ppm) A 17.90 <LOQ B 10.23 0.24 C 11.19 <LOQ D 32.57 <LOQ

[0096] As shown in Table 4, increasing the zirconia concentration on the silica base significantly improved the reduction of glycidol / glycidyl oleate in the reaction mixture.

[0097] Example 4 - Reaction temperature and its effect on total glycidol reduction

[0098] The above catalyst synthesis and reaction methods were used in the following examples. Catalyst A of the present invention was added to soybean oil admixed with glycidyl oleate. A silica / zirconia catalyst was used at 2.0 wt% based on the total weight of the catalyst and soybean oil. The reaction mixture was mixed and heated under argon to a maximum temperature of 23 °C (not heated), 45 °C, and 90 °C. As shown in Table 5 below, the concentration of total glycidol in the reaction mixture was measured before and after 7 hours, 2 hours, and half an hour, respectively.

[0099] Table 5. Glycidol reduction at various temperatures

[0100] Temperature Reaction time (hours) Initial glycidol (ppm) Final glycidol (ppm) Room temperature 7.0 20.00 1.24 45℃ 2.0 23.65 <LOQ 90℃ 0.5 17.90 <LOQ

[0101] As shown in Table 5, the catalytic reaction was carried out without any additional heat. Heating the mixture accelerated the reaction in the true catalytic form; however, excessive heat could lead to the formation of more glycidol / glycidyl oleate. For example, it was previously known that in edible oil refining, glycidyl esters are formed at temperatures of 200 °C or higher during the deodorization process.

[0102] Example 5 - Total glycidol reduction in soybean oil at 45 °C and its effect on oxidation

[0103] The above catalyst synthesis and reaction methods were used in the following examples. Catalyst A of the present invention was added to soybean oil admixed with glycidyl oleate. A silica / zirconia catalyst was used at 2.0 wt% based on the total weight of the catalyst and soybean oil. The reaction mixture was mixed and heated under argon to a maximum temperature of 45 °C. As shown in Table 6 below, the free fatty acid concentration (FFA%), p-anisidine value (p-AV), total glycidol concentration, and peroxide value (PV) in the reaction mixture were measured during a 2-hour period.

[0104] Table 6. Soybean oil oxidation at 45 °C

[0105] Reaction time FFA % p-AV PV Glycidol (ppm) Doped soybean oil 1.1 1.2 3.1 23.65 30 minutes 1.1 1.0 1.5 3.57 2 hours 1.2 1.1 1.1 <LOQ

[0106] As shown in Table 6, the free fatty acid concentration and p-anisidine value did not change, while the peroxide value and total glycidol concentration decreased during the 2-hour reaction. This indicates that no significant degradation occurred during the glycidol / glycidyl ester reduction reaction.

[0107] Example 6 - Total glycidol reduction in palm oil at 90 °C and its effect on oxidation

[0108] The above catalyst synthesis and reaction methods are used in the following examples. Catalyst A of the present invention was added to palm oil admixed with glycidyl oleate. A silica / zirconia catalyst was used at 2.0 wt% based on the total weight of the catalyst and palm oil. The reaction mixture was mixed and heated to a maximum temperature of 90 °C under argon. As shown in Table 7 below, the free fatty acid concentration, p-anisidine (p-AV) value, peroxide value (PV), and total glycidyl concentration in the reaction mixture were measured over a 30-minute period.

[0109] Table 7. Total glycidol reduction and oxidation in palm oil at 90 °C

[0110] Reaction time FFA % p-AV PV Glycidol (ppm) Doped palm oil 1.0 4.6 7.7 27.04 Heated to 90 °C 0.9 4.4 5.2 10.62 15 minutes 1.2 5.2 1.6 2.95 30 minutes 0.9 5.6 1.3 <LOQ

[0111] As shown in Table 7, the free fatty acid concentration and p-anisidine value did not change significantly, while the peroxide value and total glycidyl content decreased during the 30-minute reaction period, and the final total glycidyl content was less than the measurable amount. Palm oil is prone to oxidation when heated, which explains the small but insignificant increase in p-AV. Only reducing the reaction temperature will prevent the formation of secondary oxidation products.

[0112] Example 7 - Effect of matrix / solvent on glycidol reduction

[0113] The above catalyst synthesis and reaction methods are used in the following examples. Catalyst A of the present invention was added to a reaction matrix admixed with free glycidyl. A silica / zirconia catalyst was used at 2.0 wt% based on the total weight of the catalyst and the matrix / solvent. The reaction mixture was mixed and heated to a maximum temperature of 90 °C under argon. As shown in Table 8 below, the concentration of total glycidyl in the reaction mixture was measured after 30 minutes.

[0114] Table 8. Effect of reaction matrix on glycidol reduction

[0115] Reaction matrix Initial glycidol (ppm) Final glycidol (ppm) Doped soybean oil 76.05 0.21 Doped toluene 53.02 <LOQ

[0116] As shown in Table 8, the reaction was carried out in both edible oil and organic solvent matrices to reduce free glycidyl other than glycidyl esters.

[0117] Comparative Example 8 - Use of commercially available silica / zirconia catalyst

[0118] The above reaction process and commercially available non-porous silica / zirconia particles purchased through Fisher Scientific were used in the following examples. A 0.1 mm silica / zirconia bead sample was manufactured by Bio Spec Products (Catalog No.: NC0362415), and another 0.1 mm silica / zirconia bead sample was manufactured by Research Products International Corp (Catalog No.: 50212145). The commercially available silica / zirconia particles were added to soybean oil doped with glycidyl oleate. Silica / zirconia particles were used at 2.0 wt% based on the total weight of the particles and soybean oil. The reaction mixture was mixed and heated to a maximum temperature of 90 °C under argon. As shown in Table 9 below, the p-anisidine (p-AV) value, peroxide value (PV), and total glycidyl concentration in the reaction mixture were measured before and after 30 minutes.

[0119] Table 9. Total glycidol reduction and oxidation of commercially available silica / zirconia particles

[0120]

[0121] As shown in Table 9, compared to the silica / zirconia catalyst of the present invention described herein, the commercially available non-porous silica / zirconia particles cannot effectively reduce the total glycidyl in a given reaction mixture. Compared to the silica / zirconia catalyst of the present invention disclosed herein, these commercially available silica / zirconia particles are non-porous and have a lower surface area.

[0122] Although the present invention has been described with reference to a limited number of embodiments, these specific embodiments are not intended to limit the scope of the present invention as originally described and claimed herein. Upon review of the exemplary embodiments herein, it may be apparent to those of ordinary skill in the art that further modifications, equivalents, and variations are possible. Unless otherwise indicated, all parts and percentages in the examples and the remainder of the specification are by weight. Additionally, any numerical range such as a numerical range representing a particular set of characteristics, measurement units, conditions, physical states, or percentages described in the specification or claims is intended to be expressly incorporated herein by reference or otherwise literally to include any numerical value falling within such range, including any subset of numerical values within said any range. For example, whenever a numerical range with a lower limit R L and an upper limit Ru is disclosed, any numerical value R falling within that range is specifically disclosed. Specifically, the following numbers R within a certain range are specifically disclosed: R = R L + k(Ru - R L), where k is a variable in the range of 1% to 100% with an increment of 1%, for example, k is 1%, 2%, 3%, 4%, 5%... 50%, 51%, 52%... 95%, 96%, 97%, 98%, 99% or 100%. In addition, any numerical range represented by any two R values calculated as above is specifically disclosed. Those skilled in the art will clearly obtain any modified forms of the present invention other than those shown and described herein based on the above description and the drawings. Such modified forms are intended to fall within the scope of the appended claims. All publications cited herein are incorporated herein by reference in their entirety.

Claims

1. A method for reducing the amount of (i) glycidol, (ii) glycidyl esters, or (iii) both glycidol and glycidyl esters in a triglyceride-containing composition, the method comprising: contacting the triglyceride-containing composition with an effective amount of a particulate silica-zirconia catalyst to reduce the amount of (i) glycidol, (ii) glycidyl esters, or (iii) both glycidol and glycidyl esters in the composition, the silica-zirconia catalyst consisting of porous silica particles impregnated with zirconia, wherein the amount of (i) glycidol, (ii) glycidyl esters, or (iii) both glycidol and glycidyl esters is reduced without affecting other components of the triglyceride-containing composition, wherein the silica-zirconia catalyst comprises zirconia located in at least a portion of the pores of the porous silica particles and the silica-zirconia catalyst comprises at least 0.01% by weight of zirconia based on the total weight of the silica-zirconia catalyst, and wherein the contacting step is carried out at a temperature from room temperature to below 100 °C and a reaction time selected based on that temperature, the reaction time being sufficient to reduce the amount of glycidol, glycidyl esters, or both glycidol and glycidyl esters in the composition by more than 95% by weight and less than or equal to 99.99% by weight.

2. The method according to claim 1, wherein the silica-zirconia catalyst further comprises zirconia located on at least a portion of the surface of the porous silica particles.

3. The method according to claim 1 or 2, wherein the silica-zirconia catalyst comprises particles having a median particle size of from 0.1 micrometers (μm) to 10,000 μm.

4. The method according to claim 1 or 2, wherein the silica-zirconia catalyst comprises particles having a pore volume of at least 0.01 cubic centimeters per gram as determined by the Barrett-Joyner-Halenda (BJH) method.

5. The method according to claim 1 or 2, wherein the silica-zirconia catalyst comprises particles having a median pore diameter of at least 0.1 nanometers (nm) up to 1,000 nm as determined by a mercury intrusion test procedure using an Autopore IV 9520 purchased from Micromeritics Instrument Corp.

6. The method according to claim 1 or 2, wherein the silica-zirconia catalyst comprises particles having an average pore diameter of from 1.0 nm to 100.0 nm.

7. The method according to claim 1 or 2, wherein the silica-zirconia catalyst comprises particles having a BET particle surface area of 10 m 2 / g to 2000 m 2 / g.

8. The method according to claim 1 or 2, wherein the porous silica particles include silica gel particles, precipitated silica particles, or fumed silica particles.

9. The method according to claim 1 or 2, wherein the silica-zirconia catalyst comprises particles formed by the following steps: impregnating porous silica particles with an aqueous solution of a soluble zirconium compound; drying the impregnated porous silica particles at 105 °C for 2 hours; and The dried impregnated porous silica particles are calcined at 500 °C for 4 hours.

10. The method according to claim 9, wherein the impregnation step allows contact between the porous silica particles and the soluble zirconium compound for 30 minutes.

11. The method according to claim 9, wherein the method further comprises: After the impregnation step and before the drying step, the impregnated porous silica particles are ground for 60 minutes.

12. The method according to claim 1 or 2, wherein the contacting step is carried out at room temperature.

13. The method according to claim 1 or 2, the method further comprises: Mixing the triglyceride-containing composition and the silica-zirconia catalyst.

14. The method according to claim 13, wherein the mixing step is carried out at room temperature.

15. The method according to claim 13, the method further comprises: Heating the triglyceride-containing composition and the silica-zirconia catalyst to a temperature of 90.0 °C.

16. The method according to claim 15, wherein the heating step comprises: Heating the triglyceride-containing composition and the silica-zirconia catalyst to the maximum temperature; And Maintaining the maximum temperature for at least 10.0 minutes.

17. The method according to claim 15, wherein the heating step comprises: Heating the triglyceride-containing composition and the silica-zirconia catalyst to the maximum temperature; And Maintaining the maximum temperature for 30.0 minutes.

18. The method according to claim 15, wherein the heating step and the mixing step are carried out simultaneously.

19. The method according to claim 1 or 2, wherein the contacting step comprises: Mixing the triglyceride-containing composition and the silica-zirconia catalyst under a gas flow, the gas flow comprising nitrogen, argon, carbon dioxide or any combination thereof.

20. The method according to claim 1 or 2, wherein the contacting step comprises: Mixing the triglyceride-containing composition and the silica-zirconia catalyst under vacuum.

21. The method according to claim 1 or 2, wherein the triglyceride-containing composition comprises (i) oil, (ii) an organic solvent, or (iii) both oil and an organic solvent.

22. The method according to claim 1 or 2, wherein the triglyceride-containing composition comprises edible oil.

23. The method according to claim 1 or 2, wherein the triglyceride-containing composition comprises (i) triglyceride-based oil, (ii) an organic solvent capable of dissolving triglycerides, or (iii) both triglyceride-based oil and an organic solvent capable of dissolving triglycerides.

24. The method according to claim 1 or 2, wherein the triglyceride-containing composition comprises oils of plant origin, animal origin, microbial origin or any combination thereof.

25. The method according to claim 1 or 2, wherein the triglyceride-containing composition comprises soybean oil, palm oil, corn oil, canola oil, rapeseed oil, fish oil, algal oil, sunflower oil, olive oil, or any combination thereof.

26. The method according to claim 1 or 2, wherein the triglyceride-containing composition comprises heptane, hexane, toluene, diethyl ether, alcohol, or any combination thereof.

27. The method according to claim 1 or 2, wherein the glycidyl ester in the triglyceride-containing composition comprises glycidyl oleate.

28. The method according to claim 1 or 2, wherein the effective amount of the silica-zirconia catalyst comprises at least 0.01% by weight of the silica-zirconia catalyst based on the total weight of the silica-zirconia catalyst and the triglyceride-containing composition.

29. The method according to claim 1 or 2, wherein the method reduces the amount of (i) glycidol, (ii) glycidyl ester, or (iii) both glycidol and glycidyl ester in the triglyceride-containing composition to a level of less than 10.0 parts per million (ppm) of (i) glycidol, (ii) glycidyl ester, or (iii) both glycidol and glycidyl ester.

30. A method for preparing an edible oil, the method comprising the method according to any one of claims 22 to 29.

31. A method for preparing an edible oil according to claim 30, wherein the edible oil is subjected to a refining-bleaching-deodorization (RBD) treatment before being contacted with the silica-zirconia catalyst in the method according to any one of claims 22 to 29.

32. A method for preparing an edible oil according to claim 31, wherein the prepared edible oil does not require further processing before use.

33. A method for preparing an edible oil according to any one of claims 30 to 32, wherein the method provides a total free and bound glycidol level of less than 0.2 ppm.

34. A method for preparing an edible oil according to any one of claims 30 to 32, wherein the edible oil has an initial free fatty acid content measured as the oleic acid content, and the method changes the initial free fatty acid content measured by the AOCS official method Ca 5a-40 by less than 20%.

35. A method for preparing an edible oil according to any one of claims 30 to 32, wherein the edible oil has an initial p-anisidine value (p-AV), and the method changes the initial p-anisidine value (p-AV) measured by the AOCS official method Cd 18-90 by less than 10 units.

36. A method for preparing an edible oil according to any one of claims 30 to 32, wherein the edible oil has an initial peroxide value (PV), and the method changes the initial peroxide value measured by the AOCS official method Cd 8-53 by less than 10 units.

37. A method for reducing the amount of (i) glycidol, (ii) glycidyl esters, or (iii) both glycidol and glycidyl esters in a triglyceride-containing composition, the method comprising: Contacting the triglyceride-containing composition with an effective amount of a particulate silica-zirconia catalyst at a temperature from room temperature to less than 100 °C and a reaction time of up to 60 minutes to reduce the amount of (i) glycidol, (ii) glycidyl esters, or (iii) both glycidol and glycidyl esters in the composition, the silica-zirconia catalyst comprising porous silica particles impregnated with zirconia, wherein the amount of (i) glycidol, (ii) glycidyl esters, or (iii) both glycidol and glycidyl esters is reduced without affecting the other components of the triglyceride-containing composition, and wherein the silica-zirconia catalyst comprises at least 0.01% by weight of zirconia based on the total weight of the silica-zirconia catalyst.

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