Glycol Compositions Containing Tocopherol

Abstract

The glycol composition includes a glycol and a tocopherol blend including D-alpha tocopherol and one or more of D-beta tocopherol, D-gamma tocopherol, and D-delta tocopherol, wherein the D-alpha tocopherol is less than 50% by weight of the sum of the D-alpha tocopherol, D-beta tocopherol, D-gamma tocopherol, and D-delta tocopherol.

Description

[Technical field]

[0001] The present disclosure relates to glycol compositions, and more particularly to glycol compositions that include tocopherol. [Background technology]

[0002] Introduction Glycols based on alkyl ethers come in a variety of forms. For example, the glycols may be low molecular weight solvents or may contain polymerized portions of alkyl ethers (e.g., polyethylene glycol or propylene glycol). During storage, the glycols may oxidize and / or undergo one or more reactions that produce impurities such as formaldehyde. For certain glycol applications, the U.S. Food and Drug Administration has established maximum thresholds for formaldehyde formation during the glycol shelf life. Therefore, it is important to minimize formaldehyde formation during storage. One or more antioxidants may be included in the glycol to prevent decomposition and formaldehyde formation during storage.

[0003] Tocopherols exhibit antioxidant activity through hydrogen donation to free radicals and subsequent formation of a complex between the radical and the tocopherol radical. The use of tocopherols in glycol compositions as antioxidants is known. For example, U.S. Pat. No. 5,695,689A ("the '689 patent") discloses the use of D-alpha tocopherol and / or D-beta tocopherol with polyether polyols having a molecular weight of about 300 to about 10,000 to stabilize the polyether polyols. The '689 patent does not mention that the disclosed tocopherols are in the most effective amounts or relative amounts. There are other examples of tocopherols used as antioxidants. For example, U.S. Pat. No. 5,218,008 ("the '008 patent") discloses the use of tocopherol mixtures as antioxidants for polyether compounds. With regard to antioxidant benefits, the '008 patent explains that "most preferred is alpha-tocopherol or a mixture of tocopherols having at least 50% by weight, more preferably at least 80% by weight, of alpha-tocopherol content."

[0004] In view of the above, it would be surprising to discover a useful glycol composition utilizing a tocopherol blend in which D-alpha tocopherol is less than 50% by weight of the tocopherols in the tocopherol blend. Summary of the Invention

[0005] The present disclosure provides useful glycol compositions utilizing tocopherol blends where D-alpha tocopherol is less than 50% by weight of the tocopherols in the tocopherol blend.

[0006] The inventors of the present disclosure have surprisingly discovered that glycol compositions containing tocopherol blends exhibit a reduction in total tocopherol content when exposed to 316 stainless steel under conditions of decreasing temperature. Such conditions exist during transportation of the glycol composition by rail or truck. The reduction in total tocopherol content experienced by the glycol composition tends to increase formaldehyde levels over time (i.e., because less antioxidants are present), which may result in the glycol composition failing one or more certifications due to formaldehyde levels. Thus, reduction in tocopherol content should be avoided.

[0007] The inventors of the present disclosure have also discovered that glycol compositions comprising tocopherol blends in which D-alpha tocopherol is less than 50% by weight of the tocopherols in the tocopherol blend (i.e., the sum of D-alpha tocopherol, D-beta tocopherol, D-gamma tocopherol, and D-delta tocopherol), exhibit reduced antioxidant fading (i.e., reduced total tocopherol levels) compared to tocopherol blends in which 50% or more of the tocopherols are D-alpha tocopherol.

[0008] The present disclosure is particularly advantageous in forming glycol compositions.

[0009] According to a first aspect of the present disclosure, a glycol composition includes a glycol and a tocopherol blend including D-alpha tocopherol and one or more of D-beta tocopherol, D-gamma tocopherol, and D-delta tocopherol, wherein the D-alpha tocopherol is less than 50% by weight of the sum of the D-alpha tocopherol, D-beta tocopherol, D-gamma tocopherol, and D-delta tocopherol.

[0010] According to a second feature of the present disclosure, the glycol is 80.000% to 99.999% by weight of the total weight of the glycol composition.

[0011] According to a third feature of the present disclosure, the glycol is a polyalkylene oxide having a weight average molecular weight of 400 g / mol to 10,000,000 g / mol as measured according to gel permeation chromatography.

[0012] According to a fourth feature of the present disclosure, the glycol is a polyalkylene oxide having a weight average molecular weight of 2,000 g / mol to 5,000 g / mol as measured according to gel permeation chromatography.

[0013] According to a fifth feature of the present disclosure, the glycol is polyethylene glycol.

[0014] According to a sixth aspect of the present disclosure, the glycol composition comprises no more than 0.01 wt. % of the tocopherol blend, based on the total weight of the glycol composition.

[0015] According to a seventh aspect of the present disclosure, the glycol composition comprises 0.001 wt. % or more of the tocopherol blend, based on the total weight of the glycol composition.

[0016] According to an eighth feature of the present disclosure, D-alpha tocopherol is 0% to 40% by weight of the sum of D-alpha tocopherol, D-beta tocopherol, D-gamma tocopherol, and D-delta tocopherol.

[0017] According to a ninth feature of the present disclosure, D-alpha tocopherol is 10% to 30% by weight of the total of D-alpha tocopherol, D-beta tocopherol, D-gamma tocopherol, and D-delta tocopherol.

[0018] According to a tenth feature of the present disclosure, the formulation comprises 0.1 wt % to 99 wt % of the glycol composition, based on the total weight of the formulation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] As used herein, the term "and / or," when used with a list of two or more items, means that any one of the listed items can be used by itself, or any combination of two or more of the listed items can be used. For example, if a composition is described as containing components A, B, and / or C, the composition can contain A alone, B alone, C alone, A and B in combination, A and C in combination, B and C in combination, or A, B, and C in combination.

[0020] Unless otherwise stated, all ranges are inclusive of the endpoints.

[0021] As used herein, the term weight percent ("wt %") refers to the weight percentage that a component is based on the total weight of the glycol composition, unless otherwise specified.

[0022] As used herein, Chemical Abstract Services Registry Number ("CAS#") refers to the unique numerical identifier last assigned to a chemical compound by the Chemical Abstract Service as of the priority date of this document.

[0023] Glycol Composition The present disclosure generally relates to a glycol composition. The glycol composition includes a glycol and a tocopherol blend. The glycol composition may include one or more antioxidants or other additives designed to modify the properties or characteristics of the glycol composition.

[0024] Glycol The glycol composition comprises one or more glycols. As used herein, a glycol is defined as a chemical compound that contains two or more hydroxyl groups.Glycols are dipropylene glycol ethyl ether, tripropylene glycol ethyl ether, propylene glycol isopropyl ether, dipropylene glycol isopropyl ether, tripropylene glycol isopropyl ether, propylene glycol n-propyl ether, dipropylene glycol n-propyl ether, tripropylene glycol n-propyl ether, propylene glycol t-butyl ether, dipropylene glycol t-butyl ether, tripropylene glycol t-butyl ether, propylene glycol n-butyl ether, dipropylene glycol n-butyl ether, tripropylene glycol n-butyl ether, propylene glycol n-pentyl ether, propylene glycol n-hexyl ether, butylene glycol methyl ether, dibutylene glycol methyl ether, ethylene glycol n-butyl ether, ethylene glycol n-pentyl ether, ethylene glycol n-hexyl ether, ethylene glycol n-heptyl ether, ethylene glycol 2-ethylhexyl The low molecular weight compound may be selected from the group consisting of ethylene glycol ether, diethylene glycol n-hexyl ether, propylene glycol methyl ether acetate, propylene glycol ethyl ether acetate, propylene glycol isopropyl ether acetate, propylene glycol n-propyl ether acetate, propylene glycol n-butyl ether acetate, dipropylene glycol methyl ether acetate, dipropylene glycol ethyl ether acetate, ethylene glycol n-butyl ether acetate, propylene glycol isobutyl ether, dipropylene glycol isobutyl ether, tripropylene glycol isobutyl ether, ethylene glycol t-butyl ether, ethylene glycol isobutyl ether, ethylene glycol ethyl ether acetate, ethylene glycol isobutyl ether acetate, diethylene glycol ethyl ether acetate, dipropylene glycol dimethyl ether, and diethylene glycol n-butyl ether acetate, and combinations thereof.

[0025] Additionally or alternatively, the glycol may be a high molecular weight compound including a polymerized polyalkylene oxide. The polyalkylene oxide may be one or more of polyethylene oxide, polypropylene oxide, and polybutylene oxide. In such examples, the glycol may be polyethylene glycol, polypropylene glycol, polybutylene oxide, and combinations thereof. The polyalkylene oxide glycol may have a weight average molecular weight of 400 grams / mole ("g / mol") to 10,000,000 g / mol as measured according to gel permeation chromatography. For example, the polyalkylene oxide may have a molecular weight of 400 g / mol or more, or 500 g / mol or more, or 1,000 g / mol or more, or 1,500 g / mol or more, or 2,000 g / mol or more, or 2,500 g / mol or more, or 3,000 g / mol or more, or 3,500 g / mol or more, or 4,000 g / mol or more, or 4,500 g / mol or more, or 5,000 g / mol or more, or 5,500 g / mol or more, or 6,000 g / mol or more, or 6,500 g / mol or more, or 7,000 g / mol or more, or 7,500 g / mol or more, or 8,000 g / mol or more, or 8,500 g / mol or more, or 9,000 g / mol or more, or 9,500 g / mol or more, or 10, 000g / mol or more, or 10,500g / mol or more, or 11,000g / mol or more, or 11,500g / mol or more, or 12,000g / mol or more, or 12,500g / mol or more, or 13,000g / mol or more, or 13,500g / mol or more, or 14,000g / mol or more, or 14,500g / mol or more, or 15,000g / mol or more or above, or 20,000 g / mol, or 40,000 g / mol, or 60,000 g / mol, or 80,000 g / mol, or 100,000 g / mol, or 500,000 g / mol, or 1,000,000 g / mol, or 5,000,000 g / mol, while at the same time not exceeding 10,000,000 g / mol, or 5,000,000g / mol or less, or 1,000,000g / mol or less, or 500,000g / mol or less, or 100,000g / mol or less, or 50,000g / mol or less, or 25,000g / mol or less, or 20,000g / mol or less, or 15,000g / mol or less, or 14,500g / mol or less, or 14,000g / mol or less, or 13,500g / mol or less, or 13,000g / mol or less, or 12,500g / mol or less, or 12,000g / mol or less, or 11,500g / mol or less, or 11,000g / mol or less, or 10,500g / mol or less, or 10,000g / mol or less, or 9 ,500 g / mol or less, or 9,000 g / mol or less, or 8,500 g / mol or less, or 8,000 g / mol or less, or 7,500 g / mol or less, or 7,000 g / mol or less, or 6,500 g / mol or less, or 6,000 g / mol or less, or 5,500 g / mol or less, or 5,000 g / mol or less, or 4,500 g / mol or less, or 4,000 g / mol or less, or 3,500 g / mol or less, or 3,000 g / mol or less, or 2,500 g / mol or less, or 2,000 g / mol or less, or 1,500 g / mol or less, or 1,000 g / mol or less, or 500 g / mol or less.

[0026] The glycol composition comprises 80.000% to 99.999% by weight of glycol based on the total weight of the glycol composition. For example, the glycol composition may comprise 80.000% or more by weight, or 85.000% or more by weight, or 90.000% or more by weight, or 95.000% or more by weight, or 99.000% or more by weight, or 99.070% or more by weight, while at the same time comprising 99.999% or less by weight, or 95.000% or less by weight, or 90.000% or less by weight, or 85.000% or less by weight of glycol based on the total weight of the glycol composition.

[0027] Tocopherol Blend The tocopherol blend includes D-alpha tocopherol (CAS#59-02-9) and one or more of D-beta tocopherol (CAS#16698-35-4), D-gamma tocopherol (CAS#54-28-4), and D-delta tocopherol (CAS#119-13-1). In the tocopherol blend, D-alpha tocopherol is less than 50% by weight of the sum of D-alpha tocopherol, D-beta tocopherol, D-gamma tocopherol, and D-delta tocopherol. For example, D-alpha tocopherol may be 0.1% or more, or 1% or more, or 5% or more, or 10% or more, or 14% or more, or 15% or more, or 20% or more, or 25% or more, or 30% or more, or 35% or more, or 40% or more, or 45% or more, or 49.9% or more, while at the same time being less than 50% by weight, or 49.9% or less, or 45% or less, or 40% or less, or 35% or less, or 30% or less, or 25% or less, or 20% or less, or 15% or less, or 14% or less, or 10% or less, or 5% or less, or 1% or less by weight, based on the combined weight of D-alpha tocopherol, D-beta tocopherol, D-gamma tocopherol, and D-delta tocopherol.

[0028] The tocopherol composition may independently comprise each of D-alpha tocopherol, D-beta tocopherol, D-gamma tocopherol, and D-delta tocopherol in an amount ranging from 1% to 75% by weight based on the combined weight of D-beta tocopherol, D-gamma tocopherol, and D-delta tocopherol. For example, each of D-beta tocopherol, D-gamma tocopherol, and D-delta tocopherol may independently comprise 1% or more, or 2% or more, or 5% or more, or 10% or more, or 15% or more, or 20% or more, or 25% or more, or 30% or more, or 35% or more, or 40% or more, or 45% or more, or 50% or more by weight based on the combined weight of D-alpha tocopherol, D-beta tocopherol, D-gamma tocopherol, and D-delta tocopherol. or more than 55% by weight, or more than 60% by weight, or more than 65% by weight, or more than 70% by weight, while at the same time being less than 75% by weight, or less than 70% by weight, or less than 65% by weight, or less than 60% by weight, or less than 55% by weight, or less than 50% by weight, or less than 45% by weight, or less than 40% by weight, or less than 35% by weight, or less than 30% by weight, or less than 25% by weight, or less than 20% by weight, or less than 15% by weight, or less than 10% by weight, or less than 0.5% by weight, or less than 2% by weight. One example of a commercially suitable tocopherol blend is COVI-OX™ T-90 from BASF (Ludwigshafen, Germany).

[0029] The glycol composition comprises 0.001% to 0.01% by weight of the tocopherol composition based on the total weight of the glycol composition. For example, the glycol composition may comprise 0.001% or more by weight, or 0.002% or more by weight, or 0.003% or more by weight, or 0.004% or more by weight, or 0.005% or more by weight, or 0.006% or more by weight, or 0.007% or more by weight, or 0.008% or more by weight, or 0.009% or more by weight, while at the same time comprising 0.01% or less by weight, or 0.009% or less by weight, or 0.008% or less by weight, or 0.007% or less by weight, or 0.006% or less by weight, or 0.005% or less by weight, or 0.004% or less by weight, or 0.003% or less by weight, or 0.002% or less by weight of the tocopherol blend based on the total weight of the glycol composition.

[0030] compound The glycol composition may be used in one or more formulations. The formulation may be a cleaning composition, cosmetic composition, industrial composition, pharmaceutical, personal care material, food additive, or other material that includes the glycol composition. The formulation may include 0.1% to 99% by weight of the glycol composition based on the total weight of the formulation. For example, the formulation may include 0.1% or more by weight, or 1% or more by weight, or 5% or more by weight, or 10% or more by weight, or 20% or more by weight, or 30% or more by weight, or 40% or more by weight, or 50% or more by weight, or 60% or more by weight, or 70% or more by weight, or 80% or more by weight, or 90% or more by weight, while at the same time, 99% or less by weight, or 90% or less by weight, or 80% or less by weight, or 70% or less by weight, or 60% or less by weight, or 50% or less by weight, or 40% or less by weight, or 30% or less by weight, or 20% or less by weight, or 10% or less by weight, or 1% or less by weight of the glycol composition based on the total weight of the formulation. EXAMPLES

[0031] material The following materials were used in the examples:

[0032] PEG is a polyethylene glycol having a weight average molecular weight of 3,350 g / mol as determined by gel permeation chromatography. Polyethylene glycol is commercially available from The Dow Chemical Company (Midland, Michigan).

[0033] AO1 is a tocopherol blend having greater than 90% by weight tocopherols and having a composition of 14% by weight D-alpha tocopherol, 2% by weight D-beta tocopherol, 60% by weight D-gamma tocopherol, and 24% by weight D-delta tocopherol, based on the total weight of AO1, with the weight percentage of each individual tocopherol being based on the total weight of the sum of D-alpha tocopherol, D-beta tocopherol, D-gamma tocopherol, and D-delta tocopherol. AO1 is commercially available as COVI-OX™ T-90 from Kensing LLC (Kankakee, Illinois).

[0034] AO2 is a tocopherol blend with 537 mg / g D-alpha tocopherol and 190 mg / g non-D-alpha tocopherols (D-beta tocopherol, D-gamma tocopherol, D-delta tocopherol). AO2 is commercially available as COVITOL™ F-80 / 20M from Kensing LLC (Kankakee, Illinois).

[0035] AO3 is a tocopherol blend having approximately 960 mg / g D-alpha tocopherol and 0 mg / g non-D-alpha tocopherols (D-beta tocopherol, D-gamma tocopherol, D-delta tocopherol). AO3 is commercially available as COVITOL™ F-1490 from Kensing LLC (Kankakee, Illinois).

[0036] Sample preparation The examples were prepared by first making a masterbatch of PEG containing 0.1 wt.% of the selected antioxidant based on the total weight of the masterbatch. Different PEG and antioxidant masterbatches were made by weighing 0.1 grams ("g") (+ / - 0.008g) of the selected antioxidant into a 100 milliliter vial, followed by 99.9g of PEG. Once both materials were weighed, the vial was placed in a 70°C oven until completely melted. Once melted, the formulation was mixed for 20 minutes at a speed of 330 revolutions per minute ("RPM") on an overhead mixer maintained at 65°C. To make a formulation containing 0.002 wt.% antioxidant, 2g of the molten masterbatch was added to 98g of molten PEG and mixed for 40 minutes at 65°C on an overhead stirrer using a speed of 330 rpm. Similarly, to make a formulation containing 0.005 wt% antioxidant, 5 g of molten masterbatch was added to 95 g of molten PEG and mixed for 40 minutes at 65° C. on an overhead mixer at a speed of 330 RPM. Two replicates were made for each concentration and antioxidant. The compositions of the inventive examples ("IE") and comparative examples ("CE") are shown in Table 1.

[0037] [Table 1]

[0038] The inventive and comparative examples were tested using 316L stainless steel coupons purchased from Alabama Specialty Products Inc. (Munford, Alabama). The coupons had a flat rectangular shape with a glass bead finish (Reference Number: 316L SS UNS S31603). The coupons had dimensions of 2.54 centimeters ("cm") by 7.62 cm by 1.58 millimeters, and each weighed an average of 22.96 g. One coupon was added to 100 g of each sample in a vial, and the mixture was then subjected to a temperature decrease from 80° C. to 60° C. in 5° C. increments every 24 hours, or from 80° C. to 40° C. in 10° C. increments every 24 hours while in the oven.

[0039] The total tocopherol content of the samples was measured before and after exposure to a decreasing temperature range. Tocopherol levels were measured using liquid chromatography with ultraviolet detection. Samples taken before and after temperature exposure were heated in a 75°C oven for 1.5-2 hours until completely dissolved and homogenous liquid and gently stirred. While still homogenous liquid, 0.5 g of sample was transferred to a glass vial and methanol was added to a final weight of 5 g. A calibration curve was made by preparing different standards. Standards were prepared by making a 1 wt% stock solution and performing a series of serial dilutions down to a concentration of 0.0005 wt% in methanol. AO1 and AO3 dissolved fairly readily at higher concentrations in the stock solutions, whereas AO2 did not, and therefore a 0.1 wt% concentration stock had to be prepared for this antioxidant. Samples and standards were run using the instrument conditions detailed in Table 2.

[0040] [Table 2]

[0041] result The test results are shown in Tables 3 and 4. Total tocopherol depletion represents the percent reduction of all tocopherols in the examples after being subjected to temperature change. In other words, total tocopherol depletion is the difference between the initial tocopherol content and the final tocopherol content divided by the initial tocopherol content, then multiplied by 100. Standard deviation ("Stdev") was calculated using replicate experiments. Table 3 shows the percentage of total tocopherol depletion when the temperature is reduced from 80°C to 60°C in 5°C increments every 24 hours. Table 4 shows the percentage of total tocopherol depletion when the temperature is reduced from 80°C to 40°C in 10°C increments every 24 hours.

[0042] [Table 3]

[0043] [Table 4]

[0044] As is evident from Tables 3 and 4, IE1 and IE2, which contain tocopherol blends in which D-alpha tocopherol is less than 50% by weight of the sum of D-alpha tocopherol, D-beta tocopherol, D-gamma tocopherol, and D-delta tocopherol, exhibit much lower total tocopherol depletion compared to CE1-CE4. Such properties are advantageous in that reduced total tocopherol depletion means that a greater amount of tocopherol remains to prevent the formation of formaldehyde and other impurities. CE1 and CE2 demonstrate that glycol compositions containing tocopherol blends in which D-alpha tocopherol is more than 50% by weight of the sum of D-alpha tocopherol, D-beta tocopherol, D-gamma tocopherol, and D-delta tocopherol exhibit nearly twice the total tocopherol depletion that would be expected to increase formaldehyde and impurity levels. Similar to CE1 and CE2, CE3 and CE4 demonstrate that glycol compositions containing tocopherol blends in which D-alpha tocopherol is the only tocopherol present exhibit nearly twice the total tocopherol depletion expected to increase formaldehyde and impurity levels. Comparison of Tables 3 and 4 shows that glycol compositions containing tocopherol blends in which D-alpha tocopherol is less than 50% by weight of the sum of D-alpha tocopherol, D-beta tocopherol, D-gamma tocopherol, and D-delta tocopherol (e.g., IE1 and IE2) resist total tocopherol depletion over different temperature ranges and under different cooling rates.

Claims

1. 1. A glycol composition comprising: Glycol, and a tocopherol blend comprising D-alpha tocopherol and one or more of D-beta tocopherol, D-gamma tocopherol, and D-delta tocopherol, wherein the D-alpha tocopherol is less than 50% by weight of the sum of the D-alpha tocopherol, D-beta tocopherol, D-gamma tocopherol, and D-delta tocopherol.

2. 2. The glycol composition of claim 1, wherein said glycol is from 80.000% to 99.999% by weight of the total weight of said glycol composition.

3. 2. The glycol composition of claim 1, wherein the glycol is a polyalkylene oxide having a weight average molecular weight of from 400 g / mol to 10,000,000 g / mol as measured by gel permeation chromatography.

4. 4. The glycol composition of claim 3, wherein the glycol is a polyalkylene oxide having a weight average molecular weight of from 2,000 g / mol to 5,000 g / mol as measured by gel permeation chromatography.

5. 2. The glycol composition of claim 1, wherein the glycol is a polyethylene glycol.

6. 2. The glycol composition of claim 1, wherein said glycol composition comprises no more than 0.01% by weight of said tocopherol blend, based on the total weight of said glycol composition.

7. 7. The glycol composition of claim 6, wherein said glycol composition comprises greater than or equal to 0.001% by weight of said tocopherol blend, based on the total weight of said glycol composition.

8. 2. The glycol composition of claim 1, wherein the D-alpha tocopherol is from 0% to 40% by weight of the sum of D-alpha tocopherol, D-beta tocopherol, D-gamma tocopherol, and D-delta tocopherol.

9. 9. The glycol composition of claim 8, wherein the D-alpha tocopherol is from 10% to 30% by weight of the sum of D-alpha tocopherol, D-beta tocopherol, D-gamma tocopherol, and D-delta tocopherol.

10. A formulation comprising: Water, 0.1% to 99% by weight of the glycol composition of any one of claims 1 to 9, based on the total weight of the formulation.

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