Patent Description:
Oxo alcohols find use in many commercial products. For example, oxo alcohols can be used to synthesize plasticizers. Plasticizers are additives that increase the plasticity or fluidity of a material. Common plasticizers include phthalates and acrylates. The most dominant applications for plasticizers are in plastic materials, especially polyvinyl chloride (PVC). The properties of other materials are also improved when blended with plasticizers, for example, concrete, clays, and other related products. Accordingly, both oxo alcohols and plasticizers are considered commercially valuable products.

The production, storage and transport of oxo alcohols present many engineering challenges. Oxo alcohols must be maintained at high levels of purity, for example, less than <NUM> part per million by weight (ppm), so as not to negatively impact the quality of downstream plasticizer products. Processes such as autoxidation can occur when oxo alcohols are exposed to oxygen, resulting in the formation of unwanted aldehyde and peroxide impurities. For example, these impurities can form during the storage and/or transport of oxo alcohols and can significantly degrade plasticizer product quality. In addition, harsh weather conditions, such as temperatures in excess of <NUM>, can also accelerate the autoxidation process during storage and/or transport.

The stabilization of oxo alcohols using phenolic antioxidants is known from, for example, <CIT>. However, there is a need for a method of storing and/or transporting oxo alcohols that avoids the problem of impurity formation and does not negatively affect downstream plasticizer production.

Disclosed, in various embodiments, are methods of storing and/or transporting oxo alcohol, methods of using the oxo alcohol, and methods of making the oxo alcohol.

In an embodiment, a method of storing and/or transporting oxo alcohol comprises: combining an oxo alcohol having an initial aldehyde content X' and an initial peroxide content Y' with <NUM> ppm to <NUM> ppm of a phenolic antioxidant, preferably a phenolic antioxidant without ester linkage groups; and storing and/or transporting the oxo alcohol.

These and other features and characteristics are more particularly described below.

The invention provided herein is as defined in the claims.

The method disclosed herein for storing and/or transporting oxo alcohols can avoid the problem of impurity formation and does not negatively affect downstream plasticizer production. The method includes combining an oxo alcohol with a phenolic antioxidant, namely <NUM> ppm to <NUM> ppm of <NUM>,<NUM>-tris(<NUM>'-methyl-<NUM>'-hydroxy-<NUM>'-t- butylphenyl)butane or <NUM>,<NUM>-bis(<NUM>,<NUM>-dimethylethyl)-<NUM>-hydroxy-benzenepropanoic acid. The oxo alcohol can then be stored and/or transported for a long duration of time without compromising quality, even at temperatures in excess of <NUM> (e.g., at a temperature of up to <NUM>). For example, the duration of time can be greater than or equal to <NUM> weeks, e.g., greater than or equal to <NUM> months. Surprisingly, the presence of the phenolic antioxidant significantly reduces the occurrence of autoxidation, thus maintaining or even reducing impurity levels within the oxo alcohol during the storage and/or transport period. For example, aldehyde levels in the oxo alcohol can be less than or equal to <NUM> ppm even after <NUM> weeks of storage and/or transport. Even more surprisingly, the presence of the antioxidant does not negatively affect downstream plasticizer production. For example, plasticizer synthesized from the oxo alcohol can score best in class on the Platinum-Cobalt Scale in accordance with ASTM D1209, as updated in <NUM>.

The oxo alcohol of the present method can come from any private or commercial source. For example, the source of the oxo alcohol can be a process comprising the aldol condensation of n-butyraldehyde followed by hydrogenation of hydroxyaldehyde. The oxo alcohol can be any oxo alcohol that is suitable for the downstream production of plasticizer. For example, the oxo alcohol can comprise <NUM>-ethylhexanol, <NUM>-propylheptanol, isononyl alcohol, isodecyl alcohol, butanol, or a combination comprising at least one of the foregoing.

The oxo alcohol comprises an initial aldehyde content "X" and an initial peroxide content "Y". Desirably, the initial aldehyde content "X" is less than or equal to <NUM> ppm, preferably, less than or equal to <NUM> ppm, more preferably, less than or equal to <NUM> ppm, even more preferably, less than or equal to <NUM> ppm. The initial aldehyde content "X" can be <NUM> to <NUM> ppm. Desirably, the initial peroxide content "Y" is less than or equal to <NUM> ppm, preferably, less than or equal to <NUM> ppm, more preferably, less than or equal to <NUM> ppm. The initial peroxide content "Y" can be <NUM> to <NUM> ppm.

The oxo alcohol can be combined with <NUM>,<NUM>-bis(<NUM>,<NUM>-dimethylethyl)-<NUM>-hydroxybenzenepropanoic acid as represented by Formula I, such as Anox™ <NUM> antioxidant commercially available from Addivant™ Corporation.

The oxo alcohol can also be combined with <NUM>,<NUM>,<NUM>-tris(<NUM>'-methyl-<NUM>'-hydroxy-<NUM>'-t-butylphenyl)butane as represented by Formula <NUM>, such as Lowinox™ CA22 antioxidant commercially available from Addivant™ Corporation.

The phenolic antioxidant added to the oxo alcohol can be present in an amount of <NUM> ppm to <NUM> ppm, preferably, <NUM> to <NUM> ppm, preferably, <NUM> to <NUM> ppm, or <NUM> to <NUM> ppm, or <NUM> to <NUM> ppm. The amount of antioxidant added to the oxo alcohol can be varied in accordance with the initial aldehyde content "X" and/or the initial peroxide content "Y". For example, greater amounts of antioxidant can be added to the oxo alcohol when greater amounts of initial aldehyde content "X" and/or initial peroxide content "Y" are observed.

After combination with the antioxidant, the oxo alcohol can have a subsequent aldehyde content x and a subsequent peroxide content y. The subsequent aldehyde content x can be less than or equal to <NUM> X, preferably less than or equal to <NUM> X, or less than or equal to <NUM> X, or less than or equal to <NUM> X. The subsequent peroxide content y is less than or equal to <NUM> Y, preferably less than or equal to <NUM> Y, or less than or equal to <NUM> Y, or less than or equal to <NUM> Y.

The subsequent aldehyde content x and/or the subsequent peroxide content y can be maintained for a period of time. For example, the period can be greater than or equal to <NUM> weeks, preferably, greater than or equal to <NUM> weeks, more preferably, greater than or equal to <NUM> weeks, even more preferably, greater than or equal to <NUM> weeks. If the oxo alcohol is not combined with an antioxidant, the subsequent aldehyde content x can be greater than or equal to <NUM> X, for example, greater than or equal to <NUM> X, for example, greater than or equal to <NUM> X, after the period of time, e.g., after <NUM> months. If the oxo alcohol is not combined with an antioxidant, the subsequent peroxide content y can be greater than or equal to <NUM> Y, for example, greater than or equal to <NUM> Y, for example, greater than or equal to <NUM> Y, after the period of time; e.g., after <NUM> months.

The oxo alcohol can be stored and/or transported. For example, storage and/or transport can comprise transport via land, air, sea, or a combination comprising at least one of the foregoing. Harsh weather conditions can be experienced during storage and/or transport. For example, a temperature of the oxo alcohol can exceed <NUM>, for example, <NUM> to <NUM>, at a point during storage and/or transport. The oxo alcohol can be exposed to oxygen during storage and/ or transport. For example, the oxo alcohol can contact atmospheric air and/or compressed air during storage and/or transport. The oxo alcohol can be stored and/or transported for a period of time. The ability of the antioxidant to reduce impurity levels in the oxo alcohol can allow for these long periods of storage and/or transport.

The oxo alcohol can be stored and/or transported within a vessel, preferably, within a storage tank, mobile tank, thermal tank, pressurized tank, atmospheric tank, transport vehicle, reservoir, cylinder, or a combination comprising at least one of the foregoing. For example, the vessel can comprise steel, concrete, glass-reinforced plastic, thermoplastic, polyethylene, or a combination comprising at least one of the foregoing.

The oxo alcohol can be used for the downstream production of plasticizer. For example, the oxo alcohol can be used to produce dioctyl phthalate, trioctyl trimellitate, acrylate, or a combination comprising at least one of the foregoing. Phthalates are esters of phthalic acid and can be used effectively as plasticizers. Phthalates can be manufactured by reacting phthalic anhydride with alcohols that range from methanol and ethanol up to tridecyl alcohol, either as a straight chain or with some branching.

Plasticizer made from the oxo alcohol of the present method can be free of unwanted discolorations, even despite the presence of antioxidant in the oxo alcohol. For example, the resulting plasticizer can have a score of less than or equal to <NUM> on the Platinum-Cobalt Scale, preferably, less than or equal to <NUM>, more preferably, less than or equal to <NUM>. The Platinum-Cobalt Scale (also known as the Apha-Hazen Scale) is a color scale/index developed as a way to evaluate pollution levels in waste water. It has since expanded to a common method of comparison of the intensity of yellow-tinted samples. It is based on dilutions of a <NUM> ppm platinum-cobalt solution. The American Society for Testing and Materials (ASTM) provides detailed descriptions and procedures for the "Standard Test Method for Color of Clear Liquids (Platinum-Cobalt Scale)" under designation D1209, as updated in <NUM>.

The following examples are merely illustrative of the methods of storing and/or transporting oxo alcohols disclosed herein and are not intended to limit the scope hereof.

Experimental trials were conducted in accordance with the present method. The effects of antioxidants on aldehyde impurity levels in <NUM>-ethlyhexanol were analyzed. A fixed volume of <NUM>-ethylhexanol was admixed with an antioxidant and was heated at <NUM> for three weeks in a hot metal block. The amounts and types of antioxidants are set forth in Table <NUM>. The <NUM> temperature mimicked harsh weather conditions during which accelerated autoxidation can occur. At the end of each week (intervals of <NUM> hours), a sample was drawn and analyzed using gas chromatography (GC). A control sample (where antioxidant was not added) was also analyzed. Lowinox™ CA22 was further examined at lower concentrations of <NUM> ppm and <NUM> ppm. It was surprisingly found that Lowinox™ CA22, even at low levels of <NUM> ppm, and under stressful heated conditions, was able to stop aldehyde growth for over <NUM> weeks.

The effects of antioxidants on downstream plasticizer production were analyzed (results shown in Table <NUM>). The oxo alcohol <NUM>-ethylhexanol was mixed with different antioxidants (Anox™ <NUM> and Lowinox™ CA22). Plasticizers dioctyl phthalate (DOP) and/or trioctyl trimellitate (TOTM) were then synthesized using the different <NUM>-ethylhexanol mixtures. The DOP plasticizer was produced using a <NUM>-ethylhexanol to phthalic acid molar ratio of <NUM> to <NUM>. The TOTM plasticizer was produced using a <NUM>-ethylhexanol to trimethylaluminium molar ratio of <NUM> to <NUM>. The plasticizers were synthesized at a temperature of <NUM> for a period of <NUM> hours. Phosphorous-based antioxidants, nitrogen-based antioxidants, and sulfur-based antioxidants were all found to be problematic. For example, it was observed during downstream application that when phosphorus-based antioxidants were used, initially poor solubility in the oxo alcohol was a problem and then corrosion of the reactor. Not to be limited by theory, it is believed that during the production of the plasticizers, the phosphorus-based antioxidant would be hydrolyzed, producing phosphorus acid, which corroded the reactor. Nitrogen-based antioxidants and sulfur-based antioxidants, on the other hand, adversely affected the color of the resultant plasticizers.

Color analysis of the resulting plasticizers was conducted using the Platinum-Cobalt Scale in accordance with ASTM D1209, as updated in <NUM>. The best in class specification for TOTM plasticizer is a score of <NUM> and for the DOP plasticizer is a score of <NUM> on the Platinum-Cobalt scale. As is shown in Table <NUM>, trioctyl trimellitate and dioctyl phthalate were produced using <NUM>-ethylhexanol comprising the specified antioxidant. The results are set forth in Table <NUM>.

When <NUM>-ethylhexanol with <NUM> ppm Anox™ <NUM> was used, the resulting TOTM achieved a score of <NUM>. When <NUM>-ethylhexanol with <NUM> ppm Lowinox™ CA22 was used, the resulting TOTM achieved a score of <NUM>. When <NUM>-ethylhexanol with <NUM> ppm Lowinox™ CA22 was used, the resulting TOTM achieved a score of <NUM> and the resulting DOP achieved a score of <NUM>. Hence, if the color is an issue due to the particular use of the plasticizer, then the phenolic antioxidant without ester linking groups can be used as it had surprisingly better color.

As is evident from these results, it was surprisingly discovered that phenolic antioxidant without an additional ester-linkage group was able to stabilize the oxo alcohol and enabled the production of a plasticizer with surprisingly good color. Surprisingly, phenolic antioxidant without an additional ester-linkage group did not affect the property or quality of the <NUM>-ethylhexanol, nor did it interfere with properties of resulting downstream plasticizers.

The solubility of different antioxidants in oxo alcohol was analyzed. Alkanox™ <NUM> (not according to the claimed invention), Lowinox™ CA22, and Anox™ <NUM>, were added to <NUM>-ethylhexanol.

At a temperature of <NUM>, Lowinox™ CA22 and Anox™ <NUM> were surprisingly found to be soluble in <NUM>-ethylhexanol. Alkanox™ <NUM>, the phosphorus based antioxidant was not soluble. These results remained the same even when the amount of the antioxidant was varied from <NUM> ppm to <NUM>,<NUM> ppm.

The endpoints of all ranges directed to the same component or property are inclusive and independently combinable (e.g., ranges of "less than or equal to <NUM> wt%, or <NUM> wt% to <NUM> wt%," is inclusive of the endpoints and all intermediate values of the ranges of "<NUM> wt% to <NUM> wt%," etc.). Disclosure of a narrower range or more specific group in addition to a broader range is not a disclaimer of the broader range or larger group. "Combination" is inclusive of blends, mixtures, alloys, reaction products, and the like. Furthermore, the terms "first," "second," and the like, herein do not denote any order, quantity, or importance, but rather are used to denote one element from another. The terms "a" and "an" and "the" herein do not denote a limitation of quantity, and are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. "Or" means "and/or. " Reference throughout the specification to "one embodiment", "another embodiment", "an embodiment", and so forth, means that a particular element (e.g., feature, structure, and/or characteristic) described in connection with the embodiment is included in at least one embodiment described herein, and may or may not be present in other embodiments. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various embodiments.

Claim 1:
A method of storing and/or transporting oxo alcohol, comprising:
combining an oxo alcohol having an initial aldehyde content X and an initial peroxide content Y with <NUM> ppm to <NUM> ppm of a phenolic antioxidants; and
storing and/or transporting the oxo alcohol;
wherein the phenolic antioxidant is <NUM>,<NUM>,<NUM>-tris(<NUM>'-methyl-<NUM>'-hydroxy-<NUM>'-t-butylphenyl)butane or <NUM>,<NUM>-bis(<NUM>,<NUM>-dimethylethyl)-<NUM>-hydroxy-benzenepropanoic acid.