Hydroxylated quinone polymerization inhibitor and method of use

Abstract

Methods and compositions are described for inhibiting the polymerization of monomer (eg, styrene) compositions using hydroxylated quinone polymerization inhibitors. The hydroxylated quinone polymerization inhibitors can be used with little or no nitroxyl group-containing polymerization inhibitors, yet still provide excellent polymerization inhibitor activity in compositions containing monomers.

Description

Technical Field

[0001] The present invention relates to a composition and use of a hydroxylated quinone polymerization inhibitor compound for preventing premature polymerization of monomers.

Background Art

[0002] For example, the high-temperature treatment of hydrocarbon streams containing ethylenically unsaturated monomers such as styrene, isoprene, butadiene, etc. can be very difficult. In various chemical industry processes, the use of high temperatures to purify the above monomers can lead to polymers with undesirable problems. These vinyl monomers polymerize undesirably, especially by radical polymerization at high temperatures. Similarly, the transportation and storage of hydrocarbon streams containing vinyl species can lead to premature polymerization unless a polymerization inhibitor is added to the above streams. The polymers thus formed can precipitate from the solution and contaminate the process equipment. Removal of contaminants becomes necessary. Physical removal or cleaning of the contaminated equipment is often costly. These undesirable polymerization reactions also result in losses in production efficiency and consumption of valuable products. Undesirable polymerization reactions are particularly problematic in compositions containing vinyl aromatic monomers.

[0003] To prevent undesirable polymerization reactions, free radical polymerization inhibitors as polymerization inhibitors are often added to process streams or stored compositions. However, these compounds are generally consumed very rapidly. For example, if an emergency occurs due to mechanical or processing problems and inhibitors cannot be added, the previously added inhibitors are rapidly consumed. Subsequently, undesirable polymerization reactions recur rapidly.

[0004] Examples of polymerization inhibitors known in the art include dialkylhydroxylamines such as hydroxypropylhydroxylamine (HPHA), and stable nitroxide free radicals. Other inhibitors include N,N'-dialkylphenylenediamines, N,N'-diarylphenylenediamines and N-aryl-N'-alkylphenylenediamines. Quinonediamide compounds are another class of inhibitors. However, compounds containing nitroxide may release NO x and in some situations their use may not be desirable.

[0005] Other types of polymerization inhibitor compounds, often referred to as "retarders", slow down the rate of the polymerization reaction. However, they are often not as effective as polymerization inhibitors, particularly stable nitroxide free radicals. However, polymerization retarders are usually not consumed as quickly as polymerization inhibitors and thus tend to be more useful in the event of an emergency shutdown.

[0006] Retarders such as sulfur and dinitrophenol (DNP) compounds typified by 2,6-dinitrophenol, 2,4-dinitrocresol, and 2-sec-butyl-4,6-dinitrophenol (DNBP) were first used. However, DNP and sulfur retarders release emissions of NO X and SO X creating problems with their use. Additionally, DNP-based retarders are highly toxic, making the safety of those handling DNP-based polymerization inhibitors a major concern.

[0007] One class of compounds designed to function as safer alternatives to DNP retarders is based on quinonemethide chemistry. Quinonemethides slow the rate of polymer formation under static conditions and do not need to be frequently replenished to the process stream. However, some quinonemethide compounds do not exhibit good stability. Examples of quinonemethide compounds are in U.S. Pat. Nos. 4,003,800, 5,583,247, and 7,045,647. The production of styrene typically involves the use of both an inhibitor (e.g., an inhibitor containing a nitroxide such as TEMPO) and a retarder (e.g., a quinonemethide). In various styrene production scenarios, it is desirable to eliminate the nitroxide-containing inhibitor, but the use of only the retarder has been found to provide insufficient polymerization inhibition and make it difficult to eliminate or minimize the use of the inhibitor.

[0008] Technical challenges related to the effectiveness of compounds used to inhibit or retard polymerization reactions, as well as concerns regarding stability and safety, remain in this technical field. Despite concerns about toxicity, DNP-based polymerization inhibitors are still the most efficient retarders available. Due to safety concerns, there is a need for polymerization inhibitors that are at least as effective as DNP-type retarders but are non-toxic. SUMMARY OF THE INVENTION

[0009] The present disclosure relates to compositions and methods for inhibiting the polymerization of ethylenically unsaturated monomers such as styrene and butadiene in various processes and situations, including purification, fractionation, separation, compression, transportation, and storage of compositions containing various monomers, comprising or utilizing hydroxylated quinone polymerization inhibitors. Advantageously, the hydroxylated quinone polymerization inhibitors can be used without or with minimal use of other polymerization inhibitors, yet still provide excellent ability to inhibit the polymerization of monomers in solution.

[0010] The use of the hydroxylated quinone polymerization inhibitor composition of the present invention reduces deposits in processes, transportation, and storage facilities. Next, it can significantly reduce the polymer contamination of the purified monomer product and minimize the maintenance costs of the above facilities. Furthermore, it can also be used to suppress monomer polymerization in a composition containing a polymerizable monomer or a compound capable of forming a polymerizable monomer without the need for other types of polymerization inhibitors such as nitroxyl-based polymerization inhibitors.

[0011] In an embodiment, the present disclosure provides a method for suppressing the polymerization of monomers in a composition comprising a polymerizable monomer or a compound capable of forming a polymerizable monomer. This method includes the step of adding a hydroxylated quinone polymerization inhibitor to a composition comprising a polymerizable monomer or a compound capable of forming a polymerizable monomer, wherein the polymerization inhibitor is a compound of formula I,

Chemical formula

[0012] The hydroxylated quinone polymerization inhibitor can provide excellent polymerization inhibition activity similar to that of polymerization inhibitors containing many nitroxyls. Therefore, it is not always necessary to simultaneously add a polymerization inhibitor containing a nitroxyl compound for the treatment of hydrocarbon compositions. Next, this allows for greater flexibility in suppressing the polymerization of monomer compositions, such as when the use of polymerization inhibitors containing nitroxyls is not recommended. The compositions and methods of the present disclosure also avoid the release of NO x emissions that would otherwise result from the use of polymerization inhibitors containing nitroxyls. Thus, the treated hydrocarbon composition may contain no polymerization inhibitor containing a nitroxyl group, such as HTEMPO, or may have less than 50 ppm.

[0013] In embodiments, the hydroxylated quinone polymerization inhibitor can be provided in a composition for addition to a composition containing a polymerizable monomer or a composition capable of forming a monomer. For example, the composition can include a solvent and a polymerization inhibitor component consisting essentially of a hydroxylated quinone of formula I. Alternatively, the composition can include a solvent and a hydroxylated quinone polymerization inhibitor, provided that the composition contains little or no polymerization inhibitor containing a nitroxyl group.

Brief Description of the Drawings

[0014]

Figure 1

[0015]

Figure 2

Best Mode for Carrying Out the Invention

[0016] This disclosure provides references to preferred embodiments, and those skilled in the art will recognize that modifications may be made in form and detail without departing from the spirit and scope of the invention. References to various embodiments are not intended to limit the scope of the claims appended hereto. Further, any examples described herein are not intended to be limiting and merely describe some of the many possible embodiments of the appended claims.

[0017] Further advantages and novel features of the invention will be in part described in the following description, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention through customary experimentation.

[0018] This disclosure provides methods and compositions comprising a hydroxylated quinone polymerization inhibitor for preventing the unwanted formation of polymers in hydrocarbon compositions comprising monomers or compounds capable of forming monomers. The hydrocarbon composition can comprise one or more hydrocarbon compounds such as those derived from petroleum products obtainable from underground reservoirs, any products derived therefrom, or any mixtures thereof.

[0019] The hydroxylated quinone polymerization inhibitor compound provides excellent polymerization inhibition activity similar to that of polymerization inhibitors containing many nitroxyls. Thus, the methods of the present disclosure do not necessarily require, and preferably do not include, the co-addition of polymerization inhibitors containing nitroxyl compounds for the treatment of monomer streams. This in turn allows for greater flexibility in suppressing the polymerization of monomer compositions, such as when the use of nitroxyl-containing polymerization inhibitors is not recommended. The compositions and methods of the present disclosure also avoid the release of NO x emissions that would otherwise result from the use of nitroxyl-containing polymerization inhibitors.

[0020] A composition containing a hydroxylated quinone polymerization inhibitor and any one or more optional components can be in a desired form such as a liquid form, a dry form, or a suspension or dispersion. The hydroxylated quinone polymerization inhibitor can be in a desired physical state in the composition, such as a dissolved state, a partially dissolved state, a suspended state, or a dry mixture. Also, the hydroxylated quinone polymerization inhibitor can optionally be in a desired form in the composition, such as a particulate form. When the hydroxylated quinone polymerization inhibitor is in particulate form, the particles can optionally be described with respect to particle size (e.g., particles within a size range) and / or shape. The form of the composition and the state of the components therein can be selected by selecting the hydroxylated quinone polymerization inhibitor upon understanding its physical properties.

[0021] The form of the composition and the state of the components therein can also be affected by including one or more optional components such as a solvent or a solvent mixture, or other excipient compounds such as surfactants, dispersants. The form of the composition and the state of the components therein can also be affected by temperature, and the properties of the composition can optionally be described in a particular temperature situation (e.g., a storage temperature of 5 °C or less, room temperature (25 °C), or the temperature used for monomer synthesis and / or processing (e.g., about 100 °C or higher, about 150 °C, about 175 °C, etc.).

[0022] As described above, the hydroxylated quinone polymerization inhibitor composition can contain other components such as a solvent, a surfactant, a dispersant. When an optional component is present in the composition, it can be described with respect to the weight amount relative to the hydroxylated quinone polymerization inhibitor. Any component can be present in a weight greater than, approximately the same amount as, or less than the hydroxylated quinone polymerization inhibitor.

[0023] As used herein, the term "optionally" or "optionally" means that the thing (e.g., compound), event (e.g., processing step) or situation described thereafter may occur but need not occur, and that the description includes the case where the thing, event or situation occurs and the case where they do not occur.

[0024] The compositions of the present disclosure can include their listed compounds and optionally can include other components in the composition, but in very small amounts (e.g., as described for compositions "consisting essentially of" the listed components). For example, such compositions can include one or more other components, but not in amounts exceeding about 1% (by weight), about 0.5% (by weight), about 0.1% (by weight), or about 0.01% (by weight) of the total composition. Compositions consisting essentially of a solid component (e.g., dissolved in a solvent) that is a hydroxylated quinone polymerization inhibitor can optionally include one or more other (e.g., solid) components, but in an amount less than about 1% (by weight) of the total composition weight. In a composition "composed of" the listed components, there are no other measurable amounts of components other than the listed components. In some embodiments, the polymerization inhibitor containing nitroxyl can optionally be present in an amount less than 1% (by weight), less than 0.5% (by weight), less than 0.1% (by weight), or less than 0.01% (by weight) of the total composition, and more preferably, the polymerization inhibitor containing nitroxyl is not present at a detectable level in the composition.

[0025] "Polymerization inhibitor" broadly refers to "polymerization suppressant" and "polymerization retarder", which are generally compounds that suppress or reduce the formation of polymers from one or more radically polymerizable compounds.

[0026] In the presence of polymerizable monomers, "polymerization suppressants" such as compounds containing nitroxyl such as HTEMPO suppress the formation of polymers from their monomers during the induction time. After the induction time has elapsed, the formation of polymers occurs at substantially the same rate as in the absence of the polymerization suppressant.

[0027] "Polymerization retarders" such as the hydroxylated quinone compounds disclosed in this specification do not exhibit an induction time. Instead, once added to a polymerizable monomer composition, the rate at which polymer formation occurs is decreased compared to the rate that would have occurred in the absence of the polymerization retarder.

[0028] In contrast to polymerization retarders, polymerization inhibitors are generally consumed rapidly. Polymerization retarders slow the rate of the polymerization reaction but are not as effective as polymerization inhibitors. However, polymerization retarders are not usually consumed as quickly as polymerization inhibitors.

[0029] As used herein, the terms "substantially" and "consisting essentially of" that modify the type or amount of a component in a composition, a property, a measurable quantity, a method, a location, a value, or a range, such as when describing embodiments of the present disclosure, refer to variations that do not affect the recited composition, property, quantity, method, location, value, or range in a manner that invalidates the intended composition, property, quantity, method, location, value, or range. Examples of intended properties include, by way of non-limiting example only, dispersibility, stability, rate, solubility, etc., and intended values include the weight of an added component, the concentration of an added component, etc. The effect on the modified method includes effects caused by variations in the type or amount of materials used in the process, variations in machine settings, effects of ambient conditions on the process, etc., and the manner or degree of the effect does not invalidate one or more of the intended properties or results and similar approximate considerations. When modified by the terms "substantially" or "consisting essentially of", the claims appended to this specification include those equivalent to these types and amounts of materials.

[0030] As used herein, for example, when describing embodiments of the present disclosure, the term "about" modifying amounts, concentrations, volumes, process temperatures, process times, yields, flow rates, pressures, and similar values of components in a composition, as well as ranges thereof, refers to variations in numerical amounts that can occur by, for example, typical measurement and handling procedures used to make compounds, compositions, concentrates, or formulations; by inadvertent error in these procedures; by differences in the manufacture, source, or purity of starting materials or components used to carry out the methods; and by similar considerations of approximation. The term "about" also encompasses amounts that differ due to degradation 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. When modified by the term "about", the appended claims include equivalents of these amounts. Further, when "about" is used to describe any range of values, unless otherwise limited by the context, a description such as "about 1 to 5" means "1 to 5" and "about 1 to about 5" and "1 to about 5" and "about 1 to 5".

[0031] The compositions and methods of the present disclosure include or use polymerization inhibitors having hydroxylated quinone chemistry. In embodiments, the hydroxylated quinone polymerization inhibitor includes a partially unsaturated six-carbon ring structure having at least two, preferably two, carbonyl groups (C(O)) bonded to carbon ring atoms, and at least one, preferably two, hydroxyl groups.

[0032] In some embodiments, the hydroxylated quinone polymerization inhibitor is a compound of formula I:

Chemical formula

[0033] In some compounds of Formula I, -OR 10 is not -R 1 , -R 2 , -R 3 , and -R 4 any one or more of which is selected from the group consisting of C1-C18 alkyl, alkyl, aryl, alkylaryl and arylalkyl, alkoxy, hydroxyalkyl, -R 5 OOR 6 , -R 5 OR 6 , and -(R 5 O) n R 7 In some compounds of Formula I, -OR 10 is not -R 1 , -R 2 , -R 3 , and -R 4Two of which are independently selected from the group consisting of C1-C18 alkyl, alkyl, aryl, alkylaryl and arylalkyl, alkoxy, hydroxyalkyl, -R 5 OOR 6 、-R 5 OR 6 、and -(R 5 O) n R 7 and are independently selected from the group consisting of. -R 1 、-R 2 、-R 3 、and -R 4 Any one or more of them can include a linear, branched, or cyclic hydrocarbon structure, or a combination of these structures.

[0034] In some compounds of Formula I, -OR 10 not -R 1 、-R 2 、-R 3 、and -R 4 One of them is selected from the group consisting of linear and branched C1-C12 alkyl, alkoxy, or hydroxyalkyl, and -OR 10 not -R 1 、-R 2 、-R 3 、and -R 4 is -H. In some compounds of Formula I, -R 1 not -OH 2 、-R 3 、and -R 4 Two of them are -H.

[0035] Exemplary straight-chain alkyl groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl. Exemplary branched alkyl groups include isobutyl, sec-butyl, tert-butyl, 1-, 2-, and 3-methylbutyl, 1,1-, 1,2-, or 2,2-dimethylpropyl, 1-ethyl-propyl, 1-, 2-, 3-, or 4-methylpentyl, 1,1-, 1,2-, 1,3-, 2,2-, 2,3-, or 3,3-dimethylbutyl, 1- or 2-ethylbutyl, 1-ethyl-1-methylpropyl, and 1,1,2- or 1,2,2-trimethylpropyl.

[0036] Exemplary cycloalkyl groups include cyclopentyl, methylcyclopentyl, cyclohexyl, methylcyclohexyl, ethylcyclohexyl, propylcyclohexyl, and the like. Exemplary partially or fully unsaturated hydrocarbon groups (e.g., aryl and arylalkyl) include phenyl, benzyl, methylphenyl, ethylphenyl, and the like. Exemplary alkoxy groups include methoxymethyl, methoxyethyl, methoxypropyl, methoxybutyl, methoxypentyl, methoxyhexyl, ethoxymethyl, ethoxyethyl, and the like. Exemplary hydroxyalkyl groups include hydroxymethyl, hydroxyethyl, hydroxypropyl, hydroxybutyl, hydroxypentyl, hydroxyhexyl, and the like.

[0037] Alkylaryl groups include those of formula III: -R 8 R 9 y , wherein R 8 is a divalent hydrocarbyl group (e.g., alkylene), R 9 is an aryl group, and y is an integer of 1 or more (e.g., 2, 3, etc.). In some embodiments, R 8is C1-C12 alkylene, C1-C6 alkylene, preferably C1, C2, or C3 alkylene. Exemplary alkylaryl groups where y is 1 include benzyl, phenylethyl, phenylpropyl, and phenylbutyl. Exemplary alkylaryl groups where y is 2 include dibenzyl, diphenylethyl, diphenylpropyl, and diphenylbutyl. Optionally, an aryl (R 9 ) group can be substituted, such as having an alkyl substituent, to form an alkylarylalkyl group.

[0038] In some embodiments, the hydroxylated quinone polymerization inhibitor is a compound of Formula II:

Chemical formula

[0039] Exemplary hydroxylated quinone polymerization inhibitors include 2,5-dihydroxy-1,4-benzoquinone, 3,6-dibenzohydryl-2,5-dihydroxybenzoquinone, and 3-benzohydryl-2,5-dihydroxybenzoquinone.

[0040] The hydroxylated quinone compound can be commercially available or prepared from any one or more methods known in the art. For example, 2,5-dihydroxy-1,4-benzoquinone is available from Sigma Aldrich (St. Louis, Missouri) or Santa Cruz Biotechnology (Dallas, Texas). The hydroxylated benzoquinone derivative can be prepared by reacting a reactant such as 2,5-dihydroxy-1,4-benzoquinone with an alcohol in the presence of an acid. For example, the synthesis of aryl group-derivatized dihydroxybenzoquinone can be carried out using a method as described in Inorg. Chem. 48, 9005-9017 (2009), which involves reacting 2,5-dihydroxy-1,4-benzoquinone with benzhydrol in acetic acid containing concentrated sulfuric acid. Compounds such as 3,6-dibenzhydryl-2,5-dihydroxybenzoquinone and 3-benzhydryl-2,5-dihydroxybenzoquinone can be obtained.

[0041] The amounts of the hydroxylated quinone polymerization inhibitor and other (optional) components in the composition can be described in various ways, such as the weight percentage (% weight) or molar amount of the hydroxylated quinone polymerization inhibitor in the composition. When other components are used together with the hydroxylated quinone polymerization inhibitor, such compounds can also be described in terms of the weight ratio in the composition or the relative amounts to each other.

[0042] As discussed herein, the hydroxylated quinone can be used without or together with a minimal amount of nitroxyl groups containing a polymerization inhibitor. When a polymerization inhibitor containing a nitroxyl group is included, it can be present in very small amounts, such as in a composition containing a polymerizable monomer, and the polymerization inhibitor containing a nitroxyl group is either not present at all or present in very small amounts (less than 50 ppm).

[0043] For example, in a composition containing a polymerizable monomer and a hydroxylated quinone polymerization inhibitor, the polymerization inhibitor containing a nitroxyl group can optionally be present in an amount of less than 50 ppm, less than 25 ppm, less than 10 ppm, less than 5 ppm, less than 2.5 ppm, less than 2 ppm, less than 1.5 ppm, less than 1 ppm, less than 0.75 ppm, or less than 0.5 ppm.

[0044] Compounds containing a nitroxyl group trap monomer radicals that propagate through thermally labile species and suppress polymerization. The nitroxyl / nitroxide group, which can also be called an amine-N-oxide group, is a functional group containing an NO bond and side groups bonded to nitrogen. The nitroxide (nitroxyl) radical is an oxygen-centered radical with a delocalized free electron on the N-O bond. The polymerization inhibitor containing a nitroxide can include an N-O resonance structure that contributes to the stability of the nitroxide radical.

Chemical formula

[0045] Exemplary nitroxide-containing compounds that can be excluded from the composition or used in limited amounts according to the present disclosure include, but are not limited to: 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO), 4-hydroxy-2,2,6,6-tetramethylpiperidinyl-1-oxyl (HTMPO), 4-oxo-2,2,6,6-tetramethylpiperidinyl-1-oxyl (OTEMPO), di-tert-butyl nitroxide, 1-oxyl-2,2,6,6-tetramethyl-4-n-propoxypiperidine, 1-oxyl-2,2,6,6-tetramethyl-4-n-butoxypiperidine, 1-oxyl-2,2,6,6-tetramethyl-4-t-butoxypiperidine, 1-oxyl-2,2,6,6-tetramethyl-4-s-butoxypiperidine, 1-oxyl-2,2,6,6-tetramethyl-4-(2-methoxyethoxy)piperidine, 1-oxyl-2,2,6,6-tetramethyl-4-(2-methoxyethoxyacetoxy)piperidine, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl stearate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl acetate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl butyrate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl 2-ethylhexanoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl octanoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl laurate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl benzoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl 4-tert-butylbenzoate, 1-oxyl-2,2,6,6-tetramethyl-4-allyloxy-piperidine, 1-oxyl-2,2,6,6-tetramethyl-4-acetamidopiperidine, 1-oxyl-2,2,6,6-tetramethyl-4-(N-butylformamide)piperidine, N-(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)-caprolactam, N-(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)-dodecylsuccinimide, 1-oxyl-2,2,6,6-tetramethyl-4-(2,3-Dihydroxypropoxy)piperidine, 1-oxyl-2,2,6,6-tetramethyl-4-(2-hydroxyl-4-oxapentoxy)piperidine, and mixtures thereof. (See, e.g., U.S. Patent No. 9,266,797.) Any of these compounds can be present in a very small amount (less than 50 ppm, 25 ppm, 10 ppm, etc. as described herein) in the polymerizable monomer composition or can be completely excluded from the composition.,

[0046] Other exemplary nitroxide-containing compounds contain two or three nitroxyl groups. Such compounds can be bis-compounds or tris-compounds. Exemplary bis-nitroxide and tris-nitroxide polymerization inhibitor compounds include bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) succinate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) adipate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) sebacate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) butyl n-malonate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) phthalate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) isophthalate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) terephthalate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) hexahydroterephthalate, N,N'-bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) adipamide, 2,4,6-tris-[N-butyl-N-(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)]-s-triazine, 2,4,6-tris-[N-(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)]-s-triazine, 4,4'-ethylenebis(1-oxyl-2,2,6,6-tetramethylpiperazin-3-one), and mixtures thereof. (See, e.g., U.S. Patent No. 9,266,797.) Any of these compounds can be present in a very small amount (less than 50 ppm, 25 ppm, 10 ppm, etc. as described herein) in the polymerizable monomer composition or can be completely excluded from the composition.

[0047] Other types of compounds different from the compounds containing a nitroxyl group can also optionally be excluded from the hydroxylated quinone composition or can be used in very small amounts. For example, in some embodiments, the composition optionally excludes zinc chloride or uses very small amounts, such as less than 0.1% (by weight), less than 0.01% (by weight), less than 0.001% (by weight), or less than 0.0001% (by weight), or an undetectable amount of zinc chloride. As another example, in some embodiments, the composition optionally excludes tetrahydroquinoline or uses very small amounts, such as less than 0.1% (by weight), less than 0.01% (by weight), less than 0.001% (by weight), or less than 0.0001% (by weight), or an undetectable amount of tetrahydroquinoline.

[0048] The hydroxylated quinone polymerization inhibitor can be present in a composition containing a solvent or a combination of solvents. The solvent or combination of solvents can be selected such that one or more hydroxylated quinone polymerization inhibitors are soluble in the solvent or combination of solvents. When the hydroxylated quinone polymerization inhibitor is liquid under ambient conditions, a miscible solvent can be selected.

[0049] Useful solvents include any solvent in which the hydroxylated quinone polymerization inhibitor is soluble or can be stably suspended. In some embodiments, the solvent or combination of solvents can be selected from water-soluble or water-miscible solvents, such as glycol-based solvents, and hydrophobic or hydrocarbon solvents, such as aromatic solvents, paraffinic solvents, or a mixture of both.

[0050] Exemplary glycol solvents include C1-C8 glycols such as ethylene glycol, propylene glycol, diethylene glycol, and triethylene glycol, ethers of such glycols such as diethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol, triethylene glycol monomethyl ether, liquid polyethylene glycol, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, and low molecular weight polypropylene glycol, and combinations thereof, but are not limited thereto. Commercially available solvents such as Butyl Carbitol and Butyl CELLOSOLVE (trademark), which mainly contain Butyl CARBITOL (trademark) mainly composed of ethylene glycol monobutyl ether, can be used and are available from DOW.

[0051] Other exemplary hydrophobic or hydrocarbon solvents include heavy aromatic naphtha, toluene, ethylbenzene, isomer hexane, benzene, xylene, such as ortho-xylene, para-xylene, or meta-xylene, and mixtures of two or more thereof.

[0052] In some embodiments, the solvent is selected from glycols and aromatic naphthas and combinations thereof.

[0053] The amount of the hydroxylated quinone polymerization inhibitor in the solvent or combination of solvents (including one or more optional components) can be described in one or more ways, such as by the solid content (weight) percentage of the components in the composition or the molar amount of the solid components in the composition.

[0054] As an example, a stock composition of the hydroxylated quinone polymerization inhibitor can be dissolved in a solvent at a concentration of at least about 0.00001% (weight), at least about 5% (weight), such as in an amount in the range of about 0.00001% (weight) to about 50% (weight).

[0055] An amount of a stock composition containing a hydroxylated quinone polymerization inhibitor is added to a composition containing a monomer or a composition capable of forming a monomer to provide a polymerization inhibitor at an effective concentration to suppress the polymerization of the monomer.

[0056] The polymerizable monomer subject to polymerization inhibition by hydroxylated quinone can contain a vinyl or ethylenically unsaturated group. For example, the components of the hydroxylated quinone polymerization inhibitor and any optional components can be added to a composition containing one or more of the following polymerizable monomers: acrolein, acrylic acid, acrylonitrile, alkylated styrene, butadiene, chloroprene, divinylbenzene, ethyl acrylate, ethyl methacrylate, isoprene, methacrylic acid, methyl methacrylate, methyl acrylate, α-methylstyrene, methacrylonitrile, styrene, styrene sulfonic acid, vinyl acetate, vinyl toluene, and vinyl pyridine.

[0057] The polymerizable monomer can be present in a crude mixture of compounds, a semi-purified mixture of compounds, or a fully purified mixture of compounds. For example, the hydroxylated quinone polymerization inhibitor can be added to a process stream containing a polymerizable monomer and one or more other components different from the polymerizable monomer. In the method, the hydroxylated quinone polymerization inhibitor can be added before, during, or after (or a combination thereof) a processing step such as distillation in which the compounds in the composition are separated from each other. The hydroxylated quinone polymerization inhibitor can suppress the polymerization of the monomer at any one or more stages of the processing system, and thus can reduce or prevent deposits on the equipment.

[0058] Alternatively, the hydroxylated quinone polymerization inhibitor can be added to a process stream containing a compound that can form a polymerizable monomer such as ethylbenzene, which is a precursor of styrene (e.g., a monomer precursor). For example, in an embodiment, the composition can include a compound that can form a polymerizable monomer as an undesirable byproduct. In this situation, the presence of the hydroxylated quinone polymerization inhibitor can suppress the polymerization of the monomer if formed as a byproduct, and thus can reduce or prevent deposits on the equipment.

[0059] In an embodiment, the hydroxylated quinone polymerization inhibitor is introduced into a composition containing a monomer or a composition containing a compound capable of forming a polymerizable monomer at a desired concentration effective to suppress monomer polymerization. The hydroxylated quinone polymerization inhibitor can be added to a composition containing one or more polymerizable monomers or one or more compounds capable of forming a polymerizable monomer. The monomer and / or monomer-forming compound can be present in the composition at any concentration, for example, in very small amounts (ppm) or the monomer and / or monomer-forming compound can be present in bulk amounts (e.g., 50% (by weight) or more) in the composition. Exemplary ranges are any one from about 5 ppm, about 200 ppm, about 50 ppm, or about 100 ppm (0.1%) to about 10% (by weight), about 25% (by weight), about 50% (by weight) or about 75% (by weight).

[0060] The amount of the hydroxylated quinone polymerization inhibitor in the composition containing the monomer and / or monomer-forming compound can be selected based on the monomer / compound type, the amount of the monomer / compound in the composition, the type of the composition having the monomer / compound, any treatment of the composition, processing, or storage conditions, and different from the hydroxylated quinone polymerization inhibitor, as well as the presence of any one or more optional compounds added to the composition. The hydroxylated quinone polymerization inhibitor can be added to the composition in an amount that provides a desired level of polymerization suppression.

[0061] In embodiments, the hydroxylated quinone polymerization inhibitor can be used in an amount of at least about 0.10 ppm, for example, in the range of about 0.10 ppm to about 50,000 ppm, about 0.10 ppm to about 25,000 ppm, about 0.10 ppm to about 10,000 ppm, about 5 ppm to about 5000 ppm, about 25 ppm to about 2500 ppm, about 50 ppm to about 1,000 ppm, about 50 ppm to about 1,000 ppm, about 75 ppm to about 500 ppm, about 100 ppm to about 300 ppm, about 125 ppm to about 275 ppm, or about 150 to about 250 ppm.

[0062] In some embodiments, the hydroxylated quinone polymerization inhibitor is used before or after a composition containing a polymerizable monomer is treated with a polymerization inhibitor different from the hydroxylated quinone, such as a nitroxide-containing polymerization inhibitor (e.g., HTEMPO, etc.). In some embodiments, the hydroxylated quinone polymerization inhibitor is added to the polymerizable monomer composition after the composition has been treated with a nitroxide-containing polymerization inhibitor, and the inhibitor is at least substantially consumed or otherwise has lost at least most of its inhibitor activity. For example, a nitroxide-containing polymerization inhibitor can be added to the composition containing the monomer at an initial time point, and then the composition can be monitored to determine any increase in polymer formation and / or the presence of the inhibitor. If there is an increase in polymer formation or a decrease in the inhibitor, a hydroxylated quinone polymerization inhibitor can be added at a second time point to maintain the suppression of polymerization.

[0063] In other embodiments, the hydroxylated quinone polymerization inhibitor can be added to the composition containing the monomer at an initial time point, and then one or more other compounds useful for suppressing polymerization different from the hydroxylated quinone can be added to the composition at one or more later time points (e.g., second, third, etc.).

[0064] The hydroxylated quinone polymerization inhibitor can be added to the polymerizable monomer composition in any one or more different ways, such as single addition, continuous addition, semi - continuous addition, intermittent addition, or any combination of these methods. In continuous addition, the hydroxylated quinone polymerization inhibitor can be added at a constant or variable rate. The form of addition of the hydroxylated quinone polymerization inhibitor can be selected based on the composition containing the polymerizable monomer and how it is stored, processed, or otherwise treated. For example, in a process stream involving the transfer and separation of a polymerizable monomer, or a compound capable of forming a polymerizable monomer, from other components such as a distillation apparatus, the hydroxylated quinone polymerization inhibitor can be added continuously or semi - continuously to constitute the newly introduced monomer or monomer precursor that is constantly being introduced.

[0065] The term "deposit" refers to the formation of polymers, prepolymers, oligomers, and / or other materials that become insoluble in the stream and / or precipitate from the stream and deposit on the equipment under the conditions of operating the equipment. Next, since the hydroxylated quinone polymerization inhibitor prevents or reduces such formation, it can be called an "anti - fouling agent".

[0066] Optionally, the ability of the compositions of the present disclosure to suppress polymerization can be described in comparison with compositions that do not contain the hydroxylated quinone polymerization inhibitor or contain a comparative compound. The effect of the hydroxylated quinone polymerization inhibitor can be understood by measuring the formation of polymers (e.g., polystyrene) in a monomer (e.g., styrene) composition over time, compared to the use of a composition that does not contain the hydroxylated quinone polymerization inhibitor or a composition using a polymerization inhibitor having a different chemical nature from one of the present disclosure.

[0067] For example, the compositions of the present disclosure containing a hydroxylated quinone polymerization inhibitor can suppress monomer polymerization by more than 50%, more than 60%, more than 70%, more than 80%, more than 85%, more than 90%, more than 92.5%, more than 95%, or more than 97% compared to compositions containing non-hydroxylated quinones (e.g., dibutyl-1,4-benzoquinone) under the same conditions.

[0068] Hydroxylated quinone polymerization inhibitors are relevant to compositions and processes containing polymerizable monomers and can be used in combination with "process equipment" (reactors, reactor beds, pipes, valves, distillation columns, trays, condensers, heat exchangers, compressors, fans, impellers, pumps, recirculators, intercoolers, sensors, etc., etc.) that may be subject to deposits due to monomer polymerization. This term also includes sets of these components where multiple components are part of a "system".

[0069] In one preferred method of use, the compositions of the present disclosure containing a hydroxylated quinone polymerization inhibitor and a solvent (e.g., glycol) are used in a process that includes a distillation column used to separate and purify vinyl monomers such as styrene. For example, in processes known in the art, ethylbenzene can be subjected to a catalytic dehydrogenation reaction that results in the formation of styrene. The reaction product containing styrene also includes other materials such as aromatic compounds like toluene and benzene, unreacted ethylbenzene, polymers, etc. This mixture of compounds is generally fractionally distilled using one or more distillation columns. Usually, heat is used to assist in separating the components within the distillation column. After distillation, the separated components can be separated into streams of more pure, purified products. Optionally, the hydroxylated quinone polymerization inhibitor is used in combination with one or more secondary components such as stabilizers like butylated hydroxytoluene (BHT) and tert-butylcatechol (TBC). In an exemplary embodiment of the implementation, these components are used in a distillation column used to separate and purify vinyl monomers.

[0070] A composition containing a hydroxylated quinone polymerization inhibitor can be introduced into the stream leading from the reaction bed to the distillation column or added directly to the distillation column. The composition can be added before heating the monomer composition or while heating the monomer composition in the distillation column. In embodiments, the hydroxylated quinone polymerization inhibitor compound has a boiling point higher than the boiling point of the desired compound or distillate (e.g., a monomer such as styrene) fed to the distillation column, and during the distillation process, due to the temperature difference, the desired compound is separated from the hydroxylated quinone polymerization inhibitor compound. In embodiments, the boiling point difference between the target compound and the hydroxylated quinone polymerization inhibitor is about 10 °C or more, about 15 °C or more, about 20 °C or more, about 25 °C or more, about 30 °C or more, about 35 °C or more, about 40 °C or more, about 45 °C or more, or about 50 °C or more.

[0071] Alternatively, or in addition to adding the hydroxylated quinone polymerization inhibitor during the distillation process, the composition can optionally or further be added to a distillate stream such as a purified styrene stream. Optionally, another polymerization inhibitor can be added to the distillate stream before or together with the hydroxylated quinone polymerization inhibitor.

[0072] The hydroxylated quinone polymerization inhibitor can optionally be used in combination with one or more other components and can be used with any "hydrocarbon process stream" that can contain an unsaturated monomer to stabilize the stream during transportation and storage. In some embodiments, the hydroxylated quinone polymerization inhibitor can be used in combination with a "petroleum product" that can contain hydrocarbon products obtained from underground storage layers, any products derived therefrom, or any mixture thereof.

[0073] The polymerizable monomer is contained in petroleum products or can be chemically derived from petroleum products. Non-limiting examples of petroleum products include crude oil, reduced crude oil, crude distillates, heavy oil, or bitumen, hydrotreated oil, refined oil, by-products of petroleum product processing such as pyrolysis, hydrotreating, or phase separation, or mixtures of two or more of these, but are not limited thereto. Liquid petroleum products are petroleum products that are substantially liquid at 20°C.

[0074] The hydroxylated quinone polymerization inhibitor can be added to or can be present in a "petroleum process stream" which refers to any petroleum product disposed within petroleum process equipment in contact with the fluid on its inner surface.

[0075] The petroleum process stream can contain one or more polymerizable monomers or can be formed as a by-product. The process stream can be substantially static, such as when petroleum products are disposed within a settler (separator) or storage container for a selected contact period of up to two years. The process stream can be substantially dynamic, such as a liquid petroleum product disposed within a pipe during the transportation of a product from a first location to a second location. In some embodiments, the process stream includes one or more additional components related to petroleum processing, and such components are not particularly limited.

[0076] "Petroleum process equipment" or "petroleum process apparatus" refers to an artifact having an inner surface containing metal, and further, one or more petroleum products are determined by context at any period and at any temperature. Petroleum process equipment includes items for removing petroleum products from underground reservoirs, transporting one or more petroleum products from a first location to a second location, or separating, refining, processing, separating, distilling, reacting, metering, heating, cooling, or containing one or more petroleum products.

[0077] In embodiments, the composition containing the hydroxylated quinone polymerization inhibitor is thermally stable and has anti-polymerization activity in a process stream or a composition containing other polymerizable monomers at a temperature of about 20°C to about 400°C, such as about 100°C to about 400°C, about 100°C to about 350°C, about 100°C to about 300°C, about 100°C to about 250°C, about 100°C to about 200°C, or about 100°C to about 150°C.

[0078] In embodiments, the composition containing the hydroxylated quinone polymerization inhibitor can be introduced into a composition containing a polymerizable monomer, such as a liquid petroleum process stream, in a batch, continuous, or semi-continuous manner. In some embodiments, the hydroxylated quinone polymerization inhibitor (and any other optional components) are introduced manually. In other embodiments, their introduction is automated. In embodiments, the amount of the hydroxylated quinone polymerization inhibitor introduced over a selected unit of time varies depending on the variable composition of the associated process stream. Such variability in feed can be implemented manually by adjusting the amount of the composition up or down based on test results, or by periodically testing the inner surface of the process equipment after automatically monitoring one or more conditions inside the petroleum process equipment and being notified that more composition needs to be applied to the process stream.

[0079] In some embodiments, the hydroxylated quinone polymerization inhibitor is added to petroleum products that are crude oil, reduced crude oil, heavy oil, bitumen, coker charge, hydrotreating unit feed, hydrotreating unit effluent, flash crude oil, light cycle oil, or diesel or naphtha refining streams. In embodiments, the polymerization inhibitor is added to petroleum process equipment that is conventionally associated with the collection, treatment, transportation, or storage of one or more of crude oil, reduced crude oil, crude oil distillates, heavy oil, asphalt, coker charge, flash crude oil, light cycle oil, or diesel or naphtha refining streams, and includes pipes and related infrastructure that fluidly connect process equipment items and are used to facilitate the treatment of process streams disposed therein.

[0080] Equipment containing a composition comprising a polymerizable monomer treated with a hydroxylated quinone polymerization inhibitor and any other components can reduce or eliminate the fouled inner surfaces of the equipment. In embodiments, deposits are measured as the relative increase in solids retention in the treated composition compared to solids retention in the untreated composition over the same period. In embodiments, deposits are measured as the relative decrease in the weight or volume of deposits resulting from a selected contact period of the treated process stream within the associated process equipment item compared to the same contact period of the process equipment with the corresponding untreated process stream. Stated another way, the reduction in deposits is the measured relative decrease in the weight or volume of solids deposited or precipitated from the process equipment in contact with the treated process stream over the selected period compared to the weight or volume of solids deposited or precipitated from the untreated process stream over the same period.

[0081] The hydroxylated quinone polymerization inhibitor can also suppress unwanted polymerization and deposits in process equipment in primary fractionation processes, light end fractionation, non-aromatic vinyl halide fractionation and stabilization, process gas compression, dilution vapor systems, caustic towers, quench water towers, quench water separators, butadiene extraction, propane dehydrogenation, diesel and gasoline fuel stabilization, olefin metathesis, styrene purification, hydroxy hydrocarbon purification, and the stabilization of vinyl monomers during transportation and storage, or retard the polymerization of resins and compositions containing ethylenically unsaturated species.

[0082] The hydroxylated quinone polymerization inhibitor can be added at one or more locations at any point in the process. For example, the polymerization inhibitor composition can be added directly to an interstage cooler or compressor, or upstream of an intercooler or compressor. The hydroxylated quinone polymerization inhibitor can be added continuously or intermittently to the process equipment as needed to prevent or reduce deposits.

[0083] The hydroxylated quinone polymerization inhibitor can be introduced into the desired system by any suitable method. For example, it may be added neat or in a dilute solution. In some embodiments, a composition containing the hydroxylated quinone polymerization inhibitor is applied as a solution, emulsion, or dispersion that is sprayed, dripped, poured, or injected into a desired opening in the system, or into process equipment or process condensate. In some embodiments, it may be added to the composition together with a wash oil or conditioning water.

[0084] After introducing the composition into the process equipment, it may be observed that the treated process equipment has less deposition on the equipment than the process equipment without the addition of the composition. The reduction or prevention of deposits can be evaluated by any known method or test. In some embodiments, the reduction or prevention of deposits can be accessed by measuring the time it takes for samples with and without the antifouling composition to gel.

[0085] Example 1

[0086] Performance of 2,5-DHBQ in styrene

[0087] To screen the antioxidant performance of 2,5-dihydroxy-1,4-benzoquinone (2,5-DHBQ), a static method was used. A 200 ppm solution of 2,5-DHBQ was prepared in styrene from which the 4-tert-butylcatechol (TBC) stabilizer had been removed immediately prior to treatment with 2,5-DHBQ. An alumina column was used for the removal of the stabilizer. A solution consisting of 200 ppm of 2,5-DHBQ was prepared by dissolving 0.0715 g in freshly inhibitor-depleted styrene to produce a 350 g solution. Each of 24 Ace Glass #15 screw-type pressure tubes equipped with a PTFE screw cap and a fluoroelastomer (FETFE) O-ring was filled with 10 ml of the solution. For each test tube, the dissolved oxygen was removed from the solution by sparging with nitrogen for 2 minutes. After sparging, each tube was immediately sealed and the solution was kept under a nitrogen headspace. The tubes were loaded into a heating block preheated to 120 °C. After 30 minutes and then every 15 minutes, four tubes were removed from the block and the polymerization reaction was suppressed by cooling in an ice bath. The cooled polymer solution was immediately diluted with toluene. The polymer was measured using an in-house method.

[0088] The antioxidant performance of 2,5-DHBQ was compared with that of HTEMPO (4-hydroxy-2,2,6,6-tetramethylpiperidinyl-1-oxyl), 7-phenylquinomethide (7-PhQM), 2,4-dinitro-sec-butylphenol (DNBP), and 2,5-dihydroxy-3,6-dimethoxy-p-benzoquinone (DHDMBQ), all at 200 ppm in styrene. The results of the investigation are shown in Table 1. This is also shown in Figure 1.

Table 1

[0089] Example 2

[0090] Performance of 2,5-DHBQ in Methyl Methacrylate

[0091] A solution consisting of 20 ppm of benzoyl peroxide in methyl methacrylate was prepared. A 10-ml aliquot of the solution was added to each of 24 Ace Glass #15 screw-type pressure tubes equipped with a PTFE screw cap and a fluoroelastomer (FETFE) O-ring. As described in Example 1, dissolved oxygen was removed and excluded from the solution. The polymerization reaction was carried out by loading the tubes into a heating block preheated to 100 °C. After 30 minutes and then every 15 minutes, four tubes were removed from the block and the polymerization reaction was suppressed by cooling in an ice bath. The cooled polymer solution was immediately diluted with toluene, and the polymer content was measured immediately using a unique method.

[0092] A solution consisting of 0.58 mmol of 2,5-DHBQ and 20 ppm of benzoyl peroxide in methyl methacrylate was prepared. Using the procedure of Example 1, oxygen was removed, the solution was polymerized, and the amount of polymer formed was measured.

[0093] The performance of 2,5-DHBQ as a polymerization inhibitor was compared with HTEMPO (4-hydroxy-2,2,6,6-tetramethylpiperidinyl-1-oxyl) and para-benzoquinone (pBQ), all at 0.58 mmol in methyl methacrylate.

[0094] The results of the investigation are shown in Table 2. This is also shown in Figure 2.

Table 2

[0095] The results indicate that 2,5-DHBQ itself significantly suppresses the polymerization of methyl methacrylate and is significantly superior to HTEMPO and pBQ. Examples of embodiments of the present disclosure are listed in the following items [1] to

[21] . [1] A method for suppressing the polymerization of a monomer in a composition containing a polymerizable monomer or a polymerizable monomer-forming compound, the method comprising adding a hydroxylated quinone polymerization inhibitor to a hydrocarbon composition containing a polymerizable monomer or capable of forming a polymerizable monomer, the polymerization inhibitor being a compound of formula I,

Chem.

Chem.

[10] The method according to any one of items 1 to 9, wherein the polymerizable monomer contains a vinyl or ethylenically unsaturated group.

[11] The method according to item 10, wherein the above-mentioned polymerizable monomer is selected from the group consisting of acrylic acid, acrylonitrile, alkylated styrene, butadiene, chloroprene, divinylbenzene, ethyl acrylate, ethyl methacrylate, isoprene, methacrylic acid, methyl methacrylate, methyl acrylate, α-methylstyrene, methacrylonitrile, styrene, styrene sulfonic acid, vinyltoluene, vinylpyridine, divinylbenzene, ethylene, acetylene, methylacetylene, vinylacetylene, propylene, butene, butyne, butadiene, cyclopentadiene, dicyclopentadiene, and indene.

[12] The method according to any one of items 1 to 10, wherein the above-mentioned composition contains styrene or ethylbenzene.

[13] The method according to any one of items 1 to 12, wherein the above-mentioned composition is derived from a petroleum stream.

[14] The method according to any one of items 1 to 13, wherein the above-mentioned composition contains a hydrocarbon that is different from the above-mentioned polymerizable monomer or is its precursor.

[15] The method according to any one of items 1 to 14, which is carried out during the purification or treatment of one or more components of the above-mentioned composition.

[16] The method according to any one of items 1 to 15, wherein the above-mentioned composition does not contain a polymerization inhibitor containing a nitroxyl group or has less than 50 ppm thereof.

[17] The method according to any one of items 1 to 16, wherein the above-mentioned composition does not contain a polymerization inhibitor containing a nitroxyl group or has less than 5 ppm thereof.

[18] The method according to item 17, wherein the above-mentioned composition does not contain a polymerization inhibitor containing a nitroxyl group or has less than 0.5 ppm thereof.

[19] The method according to any one of items 1 to 18, wherein the inhibitor is a compound containing a nitroxide selected from the group consisting of 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO), 4-hydroxy-2,2,6,6-tetramethylpiperidinyl-1-oxyl (HTMPO), 4-oxo-2,2,6,6-tetramethylpiperidinyl-1-oxyl (OTEMPO), or a combination thereof.

[20] The method according to any one of items 1 to 19, wherein the above-mentioned composition (a) does not contain zinc chloride or has less than 0.1% (by weight), (b) does not contain tetrahydroquinoline or has less than 0.01% (by weight), or both (a) and (b).

[21] A composition, comprising a hydroxylated quinone polymerization inhibitor of formula I,

Chem.

Claims

1. A method for suppressing the polymerization of monomers in a liquid composition containing a polymerizable monomer or a polymerizable monomer-forming compound, wherein the liquid composition is liquid at 20 ° C, and the method comprises adding a hydroxylated quinone polymerization inhibitor to the liquid composition containing or capable of forming a polymerizable monomer, wherein the polymerization inhibitor is a compound of formula I, 【Chemical 1】 In the formula, -R １ , -R ２ , -R ３ , and -R ４ Two or three of them are -OR １０ , in the formula, R １０ is hydrogen or alkyl, and at least one of -R １０ is hydrogen, and -OR １０ -R that is not １ , -R ２ , -R ３ , and -R ４ One or two of them are -R ８ R ９ ｙ , in the formula, R ８ is a divalent hydrocarbylene group or a trivalent hydrocarbylidine group, R9 is an aryl group or an aryl group having an alkyl substituent, y is 1 or 2, -OR １０ or -R ８ R ９ ｙ -R that is not １ , -R ２ , -R ３ , and -R ４ Any one of them is hydrogen or alkyl, method.

2. -OR １０ or -R ８ R ９ ｙ -R that is not １ , -R ２ , -R ３ , and -R ４The method according to claim 1, wherein any one of them is C1-C18 alkyl.

3. -OR １０ or -R ８ R ９ ｙ -R which is not １ -R ２ -R ３ and -R ４ any one of which is independently (a) selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl; or (b) isobutyl, sec-butyl, tert-butyl, 1-methylbutyl, 2-methylbutyl, and 3-methylbutyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, and 2,2-dimethylpropyl, 1-ethyl-propyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, and 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, and 3,3-dimethylbutyl, 1-ethylbutyl, and 2-ethylbutyl, 1-ethyl-1-methylpropyl, and 1,1,2-trimethylpropyl, and 1,2,2-trimethylpropyl, the method according to claim 1.

4. The method according to claim 1, wherein the polymerization inhibitor is a compound of formula II. 【Chemical formula 2】

5. The method according to claim 4, wherein the polymerization inhibitor is 3,6-dibenzohydryl-2,5-dihydroxybenzoquinone, or 3-benzohydryl-2,5-dihydroxybenzoquinone.

6. The method according to any one of claims 1 to 5, wherein the polymerization inhibitor is present in the composition in an amount in the range of 0.1 ppm to 50000 ppm.

7. The method according to claim 6, wherein the polymerization inhibitor is present in the composition in an amount in the range of 5 ppm to 5000 ppm. **Claim 8** The method according to claim 7, wherein the polymerization inhibitor is present in the composition in an amount in the range of 75 ppm to 500 ppm. **Claim 9** The method according to any one of claims 1 to 8, wherein the polymerizable monomer contains a vinyl group. **Claim 10** The method according to claim 9, wherein the polymerizable monomer is selected from the group consisting of acrylic acid, acrylonitrile, alkylated styrene, butadiene, chloroprene, divinylbenzene, ethyl acrylate, ethyl methacrylate, isoprene, methacrylic acid, methyl methacrylate, methyl acrylate, α-methylstyrene, methacrylonitrile, styrene, styrene sulfonic acid, vinyltoluene, vinylpyridine, ethylene, vinylacetylene, propylene, and butene. **Claim 11** The method according to any one of claims 1 to 9, wherein the composition contains styrene or ethylbenzene. **Claim 12** The method according to any one of claims 1 to 11, wherein the composition is derived from petroleum. **Claim 13** The method according to any one of claims 1 to 12, wherein the composition contains a hydrocarbon that is different from or a precursor of the polymerizable monomer. **Claim 14** The method according to any one of claims 1 to 13, which is carried out during the purification or treatment of one or more components of the composition. **Claim 15** The method according to any one of claims 1 to 14, wherein the composition does not contain or contains less than 50 ppm of a polymerization inhibitor containing a nitroxyl group. **Claim 16** The method according to any one of claims 1 to 15, wherein the composition does not contain or contains less than 5 ppm of a polymerization inhibitor containing a nitroxyl group.

17. The method according to claim 16, wherein the composition does not contain a polymerization inhibitor containing a nitroxyl group or contains less than 0.5 ppm thereof.

18. The method according to any one of claims 15 to 17, wherein the polymerization inhibitor containing a nitroxyl group is selected from the group consisting of 2,2,6,6 - tetramethylpiperidinyl - 1 - oxyl (TEMPO), 4 - hydroxy - 2,2,6,6 - tetramethylpiperidinyl - 1 - oxyl (HTMPO), 4 - oxo - 2,2,6,6 - tetramethylpiperidinyl - 1 - oxyl (OTEMPO), or a combination thereof.

19. The method according to any one of claims 1 to 18, wherein the composition (a) does not contain zinc chloride or contains less than 0.1% (by weight) thereof, (b) does not contain tetrahydroquinoline or contains less than 0.01% (by weight) thereof, or is both (a) and (b).

20. A composition, comprising a hydroxylated quinone polymerization inhibitor of formula I, 【Chemical Formula 3】 wherein two or three of -R １ , -R ２ , -R ３ , and -R ４ are -OR １０ , wherein R １０ is hydrogen or alkyl, and at least one of -R １０ is hydrogen, -R １０ that is not -OR １ , -R ２ , -R ３ , and -R ４ one or two of them are -R ８ R ９ ｙ wherein R ８is a divalent hydrocarbylene group or a trivalent hydrocarbylidine group, R9 is an aryl group optionally substituted with an alkyl group, y is 1 or 2, -OR １０ or -R ８ R ９ ｙ is not -R １ , -R ２ , -R ３ , and -R ４ any of which is hydrogen or alkyl, The composition is configured to be added to a liquid composition containing a polymerizable monomer or a polymerizable monomer-forming compound to suppress the polymerization of the monomer, and the liquid composition is liquid at 20 °C, composition.

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