Polymerization inhibitor compositions having naphthoquinones and hydroxylamines and methods of use

Abstract

Compositions and methods for inhibiting and retarding the polymerization of monomer compositions using naphthoquinones and hydroxylamines are described. When present in a monomer-containing composition, the combination of naphthoquinone and hydroxylamine provides an unexpectedly beneficial polymerization inhibitor effect that inhibits the undesirable formation of contaminating polymers. The polymerization inhibitor combination can be added to hydrocarbon compositions, such as petroleum, which may contain polymerizable components such as styrene, and the hydrocarbon composition is purified or processed, such as by distillation.

Description

[Technical Field]

[0001] The present invention is directed to compositions and uses of naphthoquinones in combination with hydroxylamines to reduce the formation of polymers in monomer-containing compositions. [Background technology]

[0002] Ethylenically unsaturated monomers, such as vinyl aromatic monomers like styrene, can be present in process streams or in refined products made by various chemical industrial processes. However, these monomer types can undergo undesired polymerization by radical polymerization, especially at high temperatures. As a result, solid polymer deposits can form on process equipment surfaces during industrial manufacturing, processing, handling, or storage. The resulting polymers can be problematic and lead to equipment "fouling" and product contamination. This can therefore require treating equipment to remove the polymer or necessitate a processing step that requires operations to be stopped for physical or mechanical removal. Equally important, polymeric materials contaminate processed streams, thereby necessitating steps to remove the contaminants from composition streams or stored compositions. Consequently, these undesired polymerization reactions consume valuable reagents, resulting in reduced production efficiency, and additional steps may be required to clean equipment and / or remove the undesired polymer. Undesired polymerization reactions are particularly problematic in compositions containing vinyl aromatic monomers.

[0003] To minimize undesired polymerization reactions, compounds that act as polymerization inhibitors are often added to process streams or stored compositions. Two categories of polymerization inhibitors have been developed to minimize undesired polymerization reactions: polymerization inhibitors and polymerization retarders.

[0004] Polymerization inhibitors inhibit polymerization reactions from occurring. However, these compounds are generally consumed rapidly. For example, if an emergency occurs due to mechanical or processing problems and an inhibitor cannot be added, the previously added inhibitor will be rapidly consumed. Then, the undesired polymerization reaction will rapidly recur.

[0005] Polymerization retarders slow the rate of polymerization reactions but are not as effective as polymerization inhibitors. However, because polymerization retarders are typically not consumed as quickly as polymerization inhibitors, they tend to be more useful in the event of an emergency shutdown of operations.

[0006] Retarders such as sulfur and dinitrophenol (DNP) compounds, such as 2,6-dinitrophenol, 2,4-dinitrocresol, and 2-sec-butyl-4,6-dinitrophenol (DNBP), have been used in polymerization inhibitor methods. However, DNP and sulfur retarders have been shown to be effective in reducing NO X and SO X They release gases, making their use problematic. Additionally, DNP-based retarders are highly toxic, which is a concern during handling.

[0007] Another class of compounds designed to function as a safer alternative to DNP retarders is based on the chemistry of quinone methides. Quinone methides slow the rate of polymer formation under static conditions and do not need to be frequently re-fed to the process stream, but some quinone methide compounds do not exhibit good stability. Examples of quinone methide compounds are found in U.S. Patent Nos. 4,003,800, 5,583,247, and 7,045,647.

[0008] Another chemical used in polymerization inhibitor technology for high temperature processing of vinyl monomers is 4-hydroxy-2,2,6,6-trimethyl (HTEMPO). While effective, HTEMPO and its derivatives are effective inhibitors, not effective retarders. Summary of the Invention [Problem to be solved by the invention]

[0009] Technical challenges related to the efficacy of polymerization inhibitors or retarders, as well as stability and safety concerns remain in the art. Furthermore, the present disclosure relates to the finding that while it is desirable to combine polymerization inhibitors and retarders in the same composition, the mixtures often suffer from compatibility issues that reduce the effectiveness of both the inhibitor and retarder activity.

[0010] Recognizing the problems associated with the current state of the art of polymerization inhibitors, the current art of this application is directed to combination compositions that are safer and more effective as polymerization inhibitors in general and as retarders in particular. [Means for solving the problem]

[0011] Disclosed herein are compositions and methods for reducing polymer formation in compositions containing or capable of forming monomers. The disclosed methods utilize naphthoquinone and hydroxylamine as a combined polymerization inhibitor blend, which, when used together, exhibit unexpected beneficial polymerization inhibitor effects, such as a synergistic polymerization inhibitor effect. A mixture of naphthoquinone and hydroxylamine can provide superior activity in inhibiting the undesired polymerization of monomers such as styrene in a variety of applications, such as synthesis, purification, or storage. By using the naphthoquinone and hydroxylamine combination of the present invention, polymer contamination can be reduced, minimizing or avoiding additional processing steps. Additionally, by functioning to inhibit and delay polymerization, the mixture can minimize the accumulation of undesired polymers ("fouling") on processing or storage equipment, thereby reducing maintenance costs for such facilities. Furthermore, the combination of the present invention allows for a reduction in the amount of reagents added to the treated (e.g., hydrocarbon) composition, providing a purified product with a higher level of purity, reducing the overall cost of the product and the costs associated with its production. Additionally, the combinations of the present invention can avoid the use of other polymerization inhibitor compounds that are unsafe to use, expensive, have poor efficacy, or a combination thereof.

[0012] Also, in certain embodiments, naphthoquinone and hydroxylamine can be advantageously combined in a single package formulation for addition to a composition that can include or form a monomer, and the combination exhibits unexpected beneficial polymerization inhibitor effects, such as a synergistic polymerization inhibitor effect, during use.

[0013] In embodiments, the present disclosure provides a method for inhibiting polymerization of a monomer in a monomer-containing composition. The method includes adding a component comprising a naphthoquinone and a hydroxylamine to a composition capable of forming a polymerizable monomer. The hydroxylamine is a hydroxylamine-containing compound that reacts with a naphthoquinone to form a polymerizable monomer. 1 R2 Formula I, wherein R 1 and R 2 at least one or both of R is a carbon-containing group having 1 to 12 carbon atoms optionally substituted with one or more hydroxyl groups; 1 or R 2 is —H when not a carbon-containing group, or of formula II: [ka] wherein X is —(CHR 5 ) w - and R 5 -H,R 3 , and R 4 and R 3 is selected from —H and alkyl; R 4 is selected from -H and -OH, y is 0 or an integer ranging from 1 to 3, z is 0 or an integer ranging from 1 to 3, and w is an integer ranging from 1 to 4. The naphthoquinone and hydroxylamine present in the composition inhibit the polymerization of the polymerizable monomer.

[0014] Exemplary naphthoquinones include 1,4-naphthoquinone, 1,3-naphthoquinone, 1,2-naphthoquinone, and derivatives thereof, such as aminated derivatives of naphthoquinone.

[0015] In an exemplary embodiment, the method can include adding the naphthoquinone and hydroxylamine components to a hydrocarbon composition, such as a hydrocarbon composition that is subjected to purification or processing of one or more hydrocarbon components of the composition. The hydrocarbon composition can be derived from a petroleum material and can include a polymerizable component, such as styrene, or one or more components capable of forming a polymerizable component. For example, the naphthoquinone and hydroxylamine components can be added to a hydrocarbon composition that undergoes a distillation step or can be added to a purified composition prior to its storage or transportation.

[0016] In another embodiment, the present disclosure provides an additive composition comprising a naphthoquinone, a hydroxylamine, and a suitable solvent or solvent system. The naphthoquinone and hydroxylamine can be present in the additive composition in a predetermined concentrated amount such that when added to a monomer-containing composition, the concentrated amount is diluted to a working amount that acts in an unexpected (e.g., synergistic) manner to inhibit monomer polymerization. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a graph of the formation of polystyrene over time in a styrene monomer solution in the presence of 400 ppm N,N-diethylhydroxylamine (DEHA), 400 ppm 1,4-naphthoquinone (1,4-NQ), a combination of 200 ppm each of DEHA and 1,4-NQ, and 400 ppm 2,4-dinitro-6-sec-butylphenol (DNBP).

[0018] [Figure 2] 1 is a graph of the formation of polystyrene over time in a styrene monomer solution in the presence of 400 ppm 1,4-NQ, an unexpected (e.g., synergistic) combination of 200 ppm each of 1,4-NQ, and 400 ppm DNBP.

[0019] [Figure 3] 1 is a graph of the formation of polystyrene over time in a styrene monomer solution in the presence of 400 ppm dibenzylhydroxylamine (DBzHA), 400 ppm 1,4-NQ, the unexpected (e.g., synergistic) combination of 200 ppm each of DBzHA and 1,4-NQ, and 400 ppm DNBP. DETAILED DESCRIPTION OF THE INVENTION

[0020] While this disclosure provides reference to preferred embodiments, those skilled in the art will recognize that changes can be made in form and detail without departing from the spirit and scope of the invention. Reference to various embodiments does not limit the scope of the claims appended hereto. Moreover, any examples described herein are not intended to be limiting, but merely to describe some of the many possible embodiments of the appended claims.

[0021] Additional advantages and novel features of the present invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by routine experimentation in practicing the invention.

[0022] The present disclosure provides a method and composition that can be very effective in inhibiting the formation of undesired polymer formation in a composition containing a monomer by using naphthoquinone and hydroxylamine in combination. The observed polymerization inhibitor effect has been shown to be unexpectedly beneficial, meaning that the degree of inhibition of polymer formation is greater when naphthoquinone and hydroxylamine are used in combination compared to the degree of inhibition of polymerization when naphthoquinone and hydroxylamine are used separately, operating under the same total polymerization inhibitor concentration.

[0023] An "unexpected beneficial polymerization inhibitor combination effect" can be observed when a combination of two polymerization inhibitors (a first polymerization inhibitor and a second polymerization inhibitor) provides a level of polymerization inhibition at a total polymerization inhibitor concentration that is greater than the level of polymerization inhibition when either the first or second polymerization inhibitor is used alone at the amount of total polymerization inhibitor concentration based on the combination. For example, if a first polymerization inhibitor is used at a first concentration (e.g., 200 ppm) and provides a polymerization inhibitor activity with a level of polymerization (e.g., polystyrene formation) of "80," and a second polymerization inhibitor is also used at a first concentration (e.g., 200 ppm) and provides a polymerization inhibitor activity with a level of polymerization (e.g., polystyrene formation) of "90," then the "expected" level of polymerization inhibitor activity when the first and second polymerization inhibitors are used in combination at a total concentration of 200 ppm (e.g., 100 ppm each of the first and second polymerization inhibitors) is "85" (the average level of polymerization using the first and second polymerization inhibitors). Thus, when the combined total concentration of the first and second polymerization inhibitors is less than 85 (the expected average), or especially less than 80 (the first polymerization inhibitor), the combination of polymerization inhibitors is considered to provide "unexpected" polymerization inhibitor activity because each polymerization inhibitor is not antagonistic to the other, and the combination performs better than the average of both, or better than either the first or second polymerization inhibitor at equivalent concentrations. This unexpected level of inhibition of polymerization when the first and second polymerization inhibitors are used in combination may optionally be referred to as "synergistic," such as "synergistic polymerization inhibitor activity." Testing for unexpected polymerization inhibitor activity can also be performed when the first and second polymerization inhibitors are used in combination at different concentrations. Here, the "expected" polymerization inhibitor activity can again be calculated based on the average of the first and second polymerization inhibitors used individually in the total polymerization inhibitor concentration.The beneficial polymerization inhibitor activity of the naphthoquinone and hydroxylamine combination can be attributed to the combination's ability to very effectively inhibit and retard the formation of polymer in a monomer composition, and such activity can be observed over a period of time, as exemplified herein.

[0024] The performance of the naphthoquinone and hydroxylamine combination of the present invention can be expressed as a percent reduction (%), compared to either the naphthoquinone and hydroxylamine used at a total concentration, or the average of the naphthoquinone and hydroxylamine used individually at a total concentration.For example, using a test method such as that described herein, the formation of polymer (measured as % w / w) in a monomer composition containing either naphthoquinone and hydroxylamine at a total concentration can be determined under conditions that promote polymer formation, optionally over a period of time.The amount of polymer formation in the combined composition of naphthoquinone and hydroxylamine (each used at half the total concentration) is then determined and compared to the average of naphthoquinone and hydroxylamine, or either naphthoquinone or hydroxylamine used individually at a total concentration. In embodiments, the combination exhibits a reduction in polymerization of 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, or 80% or more, such as up to about 90% or more, compared to the average or compared to either naphthoquinone and hydroxylamine used individually at the total concentration, or a reduction in a percentage amount within any of these ranges.

[0025] An unexpected (e.g., synergistic) polymerization inhibitor effect can be observed, for example, when a combination of naphthoquinone and hydroxylamine is introduced into a hydrocarbon composition containing a polymerizable monomer or a compound capable of forming a polymerizable monomer, such as a hydrocarbon composition containing styrene. This combination can be introduced into a hydrocarbon composition undergoing refining, or into a refined hydrocarbon composition, such as one being transported or stored.

[0026] As used herein, a "polymerization inhibitor" is a compound capable of reducing the formation of polymers from one or more radically polymerizable compounds. Polymerization inhibitors can be more specifically classified as polymerization inhibitors and polymerization retarders. In the presence of polymerizable monomers, a "polymerization inhibitor" inhibits the formation of polymers from those monomers during an induction period. After the induction period has elapsed, polymer formation occurs at substantially the same rate as it would form in the absence of the polymerization inhibitor. A "polymerization retarder" does not exhibit an induction period, but instead, once added to a polymerizable monomer composition, reduces the rate at which polymer formation occurs compared to the rate at which it would form in the absence of the polymerization inhibitor. 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 usually not consumed as quickly as polymerization inhibitors. The present combination of a naphthoquinone component and a hydroxylamine component provides a beneficial polymerization inhibitor effect, thereby reducing polymer formation in the presence of a monomer-containing composition by inhibiting and delaying polymer formation. This beneficial activity can be observed over a period of time, such as that exemplified herein.

[0027] An embodiment of the present disclosure provides a composition for inhibiting monomer polymerization, comprising naphthoquinone and hydroxylamine. Compositions comprising these components (and any one or more optional components) can be in any desired form, such as a liquid form, a dry form, or a suspension or dispersion. The naphthoquinone and hydroxylamine can be in any desired physical state in the composition, such as a dissolved state, a partially dissolved state, a suspended state, or a dry mixture. The naphthoquinone and hydroxylamine can also be in any desired form in the composition, such as a particulate form. When one or more of the components are in particulate form, the particles can optionally be described in terms of particle size (e.g., particles within a certain size range) and / or shape. The form of the composition and the state of the components therein can be determined by the selection of naphthoquinone and hydroxylamine, taking into account the physical properties of each compound. The form of the composition and the state of the components therein can also be affected by the inclusion of one or more optional components, such as a solvent or solvent mixture, or other excipient compounds, such as surfactants, dispersants, etc. 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 the context of a particular temperature (e.g., a storage temperature of 5°C or below, room temperature (25°C), or a temperature used to synthesize and / or process the monomer (e.g., above about 100°C, about 150°C, about 175°C, etc.).

[0028] Compositions comprising naphthoquinone and hydroxylamine can optionally include other components in the composition (e.g., described in terms of a composition "comprising" naphthoquinone and hydroxylamine). For example, such compositions can include other components such as solvents, surfactants, dispersants, etc. If an optional component is present in the composition, it can be described in terms of its weight amount relative to one or both of the naphthoquinone compound and the hydroxylamine compound in the composition. The optional component can be present in an amount greater or less by weight than any one of the naphthoquinone and hydroxylamine, or the total amount of the naphthoquinone and hydroxylamine.

[0029] As used herein, the term "optional" or "optionally" means that the subsequently described object (e.g., compound), event (e.g., processing step), amount, or circumstance can occur, but need not occur, and that the description includes cases where the object, event, amount, or circumstance occurs as well as cases where it does not occur.

[0030] The compositions of the present disclosure can include the recited compounds and, optionally, can include other ingredients in the composition, but in very small amounts (e.g., as described in terms of a composition "consisting essentially of" the recited ingredients). For example, such compositions can include one or more other ingredients, but not in amounts greater than about 1% (by weight), about 0.5% (by weight), or about 0.1% (by weight) of the total composition. A composition consisting essentially of naphthoquinone, hydroxylamine, and solvent can optionally include one or more other ingredients, but in amounts less than about 1% (by weight) of the total composition. In a composition "consisting of" the recited ingredients, no other ingredients are present in measurable amounts other than the recited ingredients.

[0031] Similarly, the chemical properties of compounds of the present disclosure, including naphthoquinones and hydroxylamines, may, in some embodiments, be described in terms of compounds "consisting of" certain atoms or certain chemical groups. For example, in embodiments of the present disclosure, a compound such as a hydroxylamine component may consist of carbon (C), hydrogen (H), oxygen (O), and nitrogen (N), and does not have any other types of atoms in the compound other than C, H, O, and N. As another example, a compound consisting of a hydrocarbyl group, a hydroxyl group, and an amine group does not have any other chemical groups other than these.

[0032] As used herein, for example, when describing embodiments of the present disclosure, the terms "substantially" and "essentially consisting of" modify the type or amount, property, measurable amount, manner, location, value, or range of a compounded ingredient in a composition refer to variations that do not affect the generally recited composition, property, amount, manner, location, value, or range in a manner that invalidates the intended composition, property, amount, manner, location, value, or range. Examples of intended properties include, but are not limited to, dispersibility, stability, rate, solubility, and the like. Intended values ​​include the weight of an added ingredient, the concentration of an added ingredient, and the like. Effects on an altered process include effects caused by variations in the type or amount of materials used in the process, variations in machine settings, the effect of ambient conditions on the process, and the like, where the manner or degree of the effect does not invalidate one or more intended properties or results, and similar approximation considerations. When modified by the terms "substantially" or "essentially consisting of," the claims appended hereto include equivalents of these types and amounts of materials.

[0033] As used herein, for example, when describing embodiments of the present disclosure, the term "about" when used to modify the amount, concentration, volume, process temperature, process time, yield, flow rate, pressure, and similar values ​​and ranges of ingredients in a composition refers to variations in numerical quantities that may occur, for example, due to typical measuring and handling procedures used to make a compound, composition, concentrate, or use formulation; due to accidental errors in these procedures; due to differences in the manufacture, source, or purity of the starting materials or ingredients used to carry out the method; and due to similar approximation considerations. The term "about" also encompasses amounts that vary due to degradation of a formulation having a particular initial concentration or mixture, and amounts that vary due to mixing or processing a formulation having a particular initial concentration or mixture. When modified by the term "about," the claims appended hereto include equivalents of these quantities. Furthermore, when "about" is used to describe any range of values, unless otherwise limited by context, a statement such as "about 1 to 5" means "1 to 5," "about 1 to about 5," "1 to about 5," and "about 1 to 5."

[0034] Some R groups in the formulae of the present disclosure can include hydrocarbon-containing groups such as alkyl groups, including linear, branched, and cyclic alkyl groups, aryl groups, alkylaryl groups (e.g., ethyl-benzyl), arylalkyl groups (e.g., propyl-phenyl), and combinations thereof. Cyclic alkyl or aryl groups can have fused structures such as decahydronaphthalene, naphthalene, tetradecahydro-anthracene, anthracene, etc. In some embodiments, the hydrocarbon groups in the formulae of the present disclosure can be defined by the number of carbon atoms in the group, such as 1 to 12 carbons, 1 to 10 carbons, 1 to 8 carbons, 1 to 6 carbons, 1 to 5 carbons, 1 to 4 carbons, or 1 to 3 carbons.

[0035] The compositions and methods of the present disclosure include or use naphthoquinones. In embodiments, the compositions and methods of the present disclosure use one or more naphthoquinones having chemical entities based on 1,4-naphthoquinone and 1,2-naphthoquinone structures according to Formulas III and IV, respectively.

[0036] [ka]

[0037] In embodiments, in Formulas III and IV, R 1 ~R 6 is -H to provide the compounds 1,4-naphthoquinone and 1,2-naphthoquinone.

[0038] Alternatively, R 1 , R 2 , R 3 , or R 4 two adjacent groups (i.e., R 1 and R 2 , R 2 and R 3 , or R 3 and R 4 ) form one or more ring structures. This can provide, for example, an anthracene fused ring structure derived from naphthoquinone.

[0039] The compositions and methods of the present disclosure include or use naphthoquinones. In embodiments, the compositions and methods of the present disclosure use one or more naphthoquinones having chemical entities based on 1,4-naphthoquinone and 1,2-naphthoquinone structures according to Formulas III and IV, respectively.

[0040] In embodiments, in Formulas III and IV, R 1 ~R 6 is —H to provide the compounds 1,4-naphthoquinone and 1,2-naphthoquinone, respectively.

[0041] In embodiments, R 1 ~R 6is a chemical group other than -H, and such chemical group is selected from the group consisting of alkyl groups, aryl groups, alkylaryl groups, and arylalkyl groups of 1 to 24 carbon atoms.

[0042] In embodiments, the naphthoquinone is an aminated naphthoquinone. For example, in Formula III or IV, the naphthoquinone can include one or more amine groups, and -R 5 and / or -R 6 One or both of the groups may be -NR 5 R 6 and R 5 and R 6 is selected from the group consisting of hydrogen, alkyl groups of 1 to 24 carbon atoms, aryl groups, alkylaryl groups, and arylalkyl groups. Exemplary aminated naphthoquinone polymerization inhibitors can have the general chemistry of 2-amino, 1,4-naphthoquinone, 2,3-diamino, 1,4-naphthoquinone, 2-amino, 1,3-naphthoquinone, 4-amino, 1,3-naphthoquinone, 2,4-diamino, 1,3-naphthoquinone, 3-amino, 1,2-naphthoquinone, 4-amino, 1,2-naphthoquinone, and 3,4-diamino, 1,3-naphthoquinone.

[0043] Exemplary aminated naphthoquinones are described in commonly-assigned U.S. Pat. No. 11,312,792 (Masere, April 26, 2022), the disclosure of which is incorporated herein by reference.

[0044] The compositions and methods of the present disclosure include or utilize hydroxylamines in conjunction with naphthoquinones, which, when present together in a monomer-containing composition, provide unexpected (e.g., synergistic) polymerization inhibitor benefits.

[0045] Hydroxylamine compounds have one or more amine groups bonded to a hydroxyl group. In some embodiments, the hydroxylamine compound is a "primary hydroxylamine," which refers to a compound having a nitrogen atom bonded to a chemical group other than a hydroxyl group or hydrogen, such as a hydroxyl group (-OH), hydrogen (-H), and a hydrocarbon-containing group. In some embodiments, the hydroxylamine compound is a "secondary hydroxylamine," which refers to a compound having a nitrogen atom bonded to two chemical groups other than a hydroxyl group or hydrogen, such as a hydroxyl group (-OH) and a hydrocarbon-containing group, or alternatively, the secondary hydroxylamine is a cyclic compound in which the nitrogen is a heteroatom in a ring structure and is also bonded to a hydroxyl group.

[0046] Hydroxylamines can also be described in terms of atomic composition, for example, hydroxylamines having one or more primary hydroxylamine groups and / or one or more secondary hydroxylamine groups, and at least 1, at least 2, at least 3, or at least 4 carbon atoms, and up to 60, up to 48, up to 36, up to 24, up to 18, up to 15, or up to 12 carbon atoms. In some preferred embodiments, the hydroxylamine has a number of carbons in the range of 3 to 24, in the range of 3 to 18, or in the range of 3 to 15.

[0047] The hydroxylamine can contain one or more oxygen atoms, at least one of which is in the form of a hydroxyl group attached to a nitrogen on the hydroxylamine group. In embodiments, the hydroxylamine has a number of oxygen atoms in the range of 1 to 8, 1 to 6, 1 to 4, or 1 to 3. In embodiments where the hydroxylamine contains two of the more oxygen atoms, most or all of the oxygen atoms can be in the form of hydroxyl groups in the hydroxylamine.

[0048] Hydroxylamines can consist of certain atoms to the exclusion of others, hi some embodiments, the hydroxylamine consists of nitrogen, carbon, oxygen, and hydrogen atoms.

[0049] In embodiments, the hydroxylamine has the formula I: HO-NR 1 R 2 wherein R 1 and R 2 at least one or both of R is a carbon-containing group having 1 to 12 carbon atoms optionally substituted with one or more hydroxyl groups; 1 or R 2 is -H when it is not a carbon-containing group. 1 R 2 )R 1 can be selected from (i) a C1-C12 alkyl group, (ii) a C1-C8 alkyl group, and (iii) a C1-C6 alkyl group, and (i) to (iii) have a linear, branched, or cyclic structure, or a combination thereof. 1 R 2 )R 2 can be selected from (iv) —H and a C1-C12 alkyl group, (v) —H and a C1-C8 alkyl group, or (vi) —H and a C1-C6 alkyl group, wherein the alkyl groups in (iv)-(vi) have a linear, branched, or cyclic structure, or a combination thereof, and any one or more alkyl groups in (i)-(vi) are optionally substituted with one or more hydroxyl groups.

[0050] In embodiments, the compound of formula I(HO-NR 1 R 2 ) in R 1 or / and R 2 One or both of may be selected from linear, branched, and cyclic alkyl, aryl, alkyl-aryl, and aryl-alkyl C1-C12 groups. Exemplary R 1 or / and R 2Groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, cyclopentyl, isopentyl, neopentyl, hexyl, cyclohexyl, 1-, 2-, and 3-methylbutyl, 1,1-, 1,2-, or 2,2-dimethylpropyl, 1-ethylpropyl, 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, methylcyclopentyl; heptyl, 2-methylhexyl, 3-methylhexyl, 4-methylhexyl, 5-methylhexyl, 3-ethylpentyl, 2,2,3-trimethylbutyl, 2,2-dimethylpentyl, 2,3-dimethylpentyl , 2,4-dimethylpentyl, 3,3-dimethylpentyl, 3,4-dimethylpentyl, 4,4-dimethylpentyl, cycloheptyl, 1-methylcyclohexyl, and 2-methylcyclohexyl; octyl, 2-methylheptyl, 3-methylheptyl, 4-methylheptyl, 2-ethylhexyl, 3-ethylhexyl, 4-ethylhexyl, 5-ethylhexyl, 2,2-dimethylhexyl, 2,3-dimethylhexyl, 2,4-dimethylhexyl, 2,5-dimethylhexyl, 3,3-dimethylhexyl, 3,4-dimethylhexyl, 3-ethyl-2-methylpentyl, 3-ethyl-3-methylpentyl, 2,2,3-trimethylpentyl, 2,2,4-trimethylpentyl, 2,3,3-trimethylpentyl, 2,3,4-trimethylpentyl, and 2,2,3,3-tetramethylbutyl.

[0051] In embodiments, the compound of formula I(HO-NR 1 R 2 ) in R 1 or / and R 2 may be independently selected from hydroxylated linear, branched, and cyclic alkyl, aryl, alkyl-aryl, and aryl-alkyl C1-C12 groups. 1 and R 2 One or both of the formula: -(CR 10 2)q (CHOH)(CH2) z R 11 wherein R 10 is independently selected from —H and alkyl, q and z are independently (−) (a covalent bond) or an integer ranging from 1 to 12, and R 11 is selected from the group consisting of C1-C12 linear, branched, or cyclic alkyl, aryl, alkyl-aryl, and aryl-alkyl, optionally substituted with one or more hydroxyl groups. In embodiments, q and z are independently (-), 1, or 2. In some embodiments, R 10 is -H, q is 1, z is (-), and R 11 can be selected from linear, branched, or cyclic alkyl, aryl, alkyl-aryl, and aryl-alkyl C1-C12 groups. Exemplary alkyl, alkyl-aryl, and aryl-alkyl groups are described herein. 10 2) q (CHOH)(CH2) z R 11 Exemplary species of include the following groups: [ka]

[0052] In embodiments, a carbon-containing group of formula I(HO-NR 1 R 2 ) in R 1 or / and R 2 One or both of R 1 and R 2 is of formula V: [ka] In the formula, R 6 is independently selected from the group consisting of —H, —OH, and alkyl; v is an integer ranging from 1 to 6; R 7 is independently selected from the group consisting of -H, -OH, and alkyl, and q is an integer ranging from 1 to 5.

[0053] In embodiments, -(CHR 6 ) v - is the formula -(CR 10 2) q (CHOH)(CH2) z -, which is exemplified by the following groups: [ka]

[0054] In some embodiments, the hydroxylamine is selected from the group consisting of benzylhydroxylamine, N-phenethyl-hydroxylamine, N-(3-phenyl-propyl)-hydroxylamine, N-(4-phenyl-butyl)-hydroxylamine, N-(5-phenyl-pentyl)-hydroxylamine, N-(6-hexyl-propyl)-hydroxylamine, N-(3-phenyl-2-methyl-propyl)-hydroxylamine, and N-(4-phenyl-3-methyl-butyl)-hydroxylamine.

[0055] In some embodiments, the hydroxylamine is selected from the group consisting of dibenzylhydroxylamine, N,N-bis(phenethyl)hydroxylamine, N,N-bis(3-phenylpropyl)hydroxylamine, N,N-bis(4-phenyl-butyl)-hydroxylamine, N,N-bis(5-phenyl-pentyl)-hydroxylamine, N,N-bis(6-hexyl-propyl)-hydroxylamine, N,N-bis(3-phenyl-2-methyl-propyl)-hydroxylamine, and N,N-bis(4-phenyl-3-methyl-butyl)-hydroxylamine.

[0056] In some embodiments, the hydroxylamine is selected from the group consisting of N-(2-phenyl-1-hydroxyl-ethyl)-hydroxylamine, N-(3-phenyl-2-hydroxyl-propyl)-hydroxylamine, N-(4-phenyl-2-hydroxyl-butyl)-hydroxylamine, N-(5-phenyl-2-hydroxyl-pentyl)-hydroxylamine, N-(6-hexyl-2-hydroxyl-propyl)-hydroxylamine.

[0057] In some embodiments, the hydroxylamine is selected from the group consisting of N,N-bis(2-phenyl-1-hydroxyl-ethyl)hydroxylamine, N,N-bis(3-phenyl-2-hydroxyl-propyl)-hydroxylamine, N,N-bis(4-phenyl-2-hydroxyl-butyl)-hydroxylamine, N,N-bis(5-phenyl-2-hydroxyl-pentyl)-hydroxylamine, and N,N-bis(6-hexyl-2-hydroxyl-propyl)-hydroxylamine.

[0058] In some embodiments, the compound of formula I is N,N-dimethylhydroxylamine, N-methyl-N-ethylhydroxylamine, N-methyl-N-propylhydroxylamine, N-methyl-N-isopropylhydroxylamine, N-methyl-N-propylhydroxylamine, N-methyl-N-butylhydroxylamine, N-methyl-N-isobutylhydroxylamine, N-methyl-Nt-butylhydroxylamine, N-,N-diethylhydroxylamine, N-ethyl-N-propylhydroxylamine, N-ethyl-N-isopropylhydroxylamine, N-ethyl-N-propylhydroxylamine, and n-butylhydroxylamine, N-ethyl-N-butylhydroxylamine, N-ethyl-N-isobutylhydroxylamine, N-ethyl-Nt-butylhydroxylamine, N-,N-dipropylhydroxylamine, N-,N-diisopropylhydroxylamine, N-propyl-N-butylhydroxylamine, N-isopropyl-N-butylhydroxylamine, N-propyl-N-isobutylhydroxylamine, N-propyl-Nt-butylhydroxylamine, N-isopropyl-N-isobutylhydroxylamine, and N-isopropyl-Nt-butylhydroxylamine.

[0059] In some embodiments, the compound of formula I is N-methylhydroxylamine, N-ethylhydroxylamine, N-propylhydroxylamine, N-isopropylhydroxylamine, N-butylhydroxylamine, N-isobutylhydroxylamine, Nt-butylhydroxylamine, N-sec-butylhydroxylamine, N-pentylhydroxylamine, N-cyclopentylhydroxylamine, N-isopentylhydroxylamine, N-neopentylhydroxylamine, N-hexylhydroxylamine, N-cyclohexylhydroxylamine, N-1-, 2-, and 3-methylbutylhydroxylamine. hydroxylamine, N-1,1-, 1,2-, or 2,2-dimethylpropylhydroxylamine, N-1-ethylpropylhydroxylamine, 1-, 2-, 3-, or 4-methylpentylhydroxylamine, N-1,1-, 1,2-, 1,3-, 2,2-, 2,3-, or 3,3-dimethylbutylhydroxylamine, N-1- or 2-ethylbutylhydroxylamine, N-1-ethyl-1-methylpropylhydroxylamine, and N-1,1,2- or 1,2,2-trimethylpropylhydroxylamine, and N-methylcyclopentylhydroxylamine.

[0060] In some embodiments, the compound of formula I is selected from the group consisting of N-hydroxymethylhydroxylamine, N-1- or 2-hydroxyethylhydroxylamine, N-1-, 2-, or 3-hydroxypropylhydroxylamine, N-1- or 2-hydroxypropylhydroxylamine, N-1-, 2-, 3-, or 4-hydroxybutylhydroxylamine, N-1-, 2-, or 3-hydroxyisobutylhydroxylamine, N-1-, 2-, or 3-hydroxysecbutylhydroxylamine, N-2-hydroxy-t-butylhydroxylamine, and N-1-, 2-, 3-, 4, or 5-N-hydroxypentylhydroxylamine.

[0061] In some embodiments, the compound of formula I is selected from the group consisting of N,N-bis(hydroxymethyl)hydroxylamine, N,N-bis(1-, or 2-hydroxyethyl)hydroxylamine, N,N-bis(1-, 2-, or 3-hydroxypropyl)hydroxylamine, N,N-bis(1-, or 2-hydroxypropyl)hydroxylamine, N,N-bis(1-, 2-, 3-, or 4-hydroxybutyl)hydroxylamine, N,N-bis(1-, 2-, or 3-hydroxyisobutyl)hydroxylamine, N,N-bis(1-, 2-, or 3-hydroxysecbutyl)hydroxylamine, N,N-bis(2-hydroxy-t-butyl)hydroxylamine, and N,N-bis(1-, 2-, 3-, 4, or 5-N-hydroxypentyl)hydroxylamine.

[0062] In some embodiments, the hydroxylamine is of formula II: [ka] In the formula, X is -(CHR 5 ) w - and R 5 -H,R 3 , and R 4 and R 3 is selected from —H and alkyl; R 4 is selected from -H and -OH; y is 0 or an integer ranging from 1 to 3; z is 0 or an integer ranging from 1 to 3; and w is an integer ranging from 1 to 4.

[0063] Exemplary species of Formula II include N-hydroxypyrrolidine, N-hydroxypiperidine, azepanol, and azocanol.

[0064] Other exemplary species of Formula II include alkylated, such as those with C1-C6 alkylation, N-hydroxypyrrolidine, N-hydroxypiperidine, azepanol, and azocanol, hydroxylated N-hydroxypyrrolidine, N-hydroxypiperidine, azepanol, and azocanol, and compounds with both alkylation and hydroxylation.

[0065] Hydroxylamines of the present disclosure are generally in liquid or solid form at room temperature (25°C). Some hydroxylamines having a carbon atom number or alkyl chain length of about 12 may be in solid form at room temperature. In some embodiments, the hydroxylamine compounds of the present disclosure have a melting point in the range of about -50°C to about 200°C, about -30°C to about 150°C, or about -10°C to about 125°C. In some embodiments, the hydroxylamine compounds of the present disclosure have a boiling point of about 100°C or higher, about 110°C or higher, about 120°C or higher, about 130°C or higher, about 140°C or higher, about 150°C or higher, about 160°C or higher, about 170°C or higher, about 175°C or higher, about 180°C or higher, about 185°C or higher, about 190°C or higher, or about 195°C or higher, such as in the range of about 100°C to about 300°C, or about 150°C to about 250°C.

[0066] The amounts of naphthoquinone and hydroxylamine in the composition can be described in various ways, such as by the weight percent (% wt) of each component in the composition or by the molar amounts of the compounds. These compounds can also be described in terms of their weight ratios in the composition or in terms of their relative amounts to each other.

[0067] In some embodiments, the naphthoquinone and hydroxylamine are used in the composition in a desired molar ratio, such as in the range of 10:1 to 1:10, 5:1 to 1:5, 2.5:1 to 1:2.5, 2:1 to 1:2, 1.5:1 to 1:1.5, 1.25:1 to 1:1.25, or 1.1:1 to 1:1.1. In some embodiments, the naphthoquinone and hydroxylamine are used in approximately equal molar amounts.

[0068] Naphthoquinone and hydroxylamine can be present in a composition with a solvent or a combination of solvents.The solvent or the combination of solvents can be selected so that at least one of naphthoquinone and hydroxylamine is soluble in the solvent or the combination of solvents.If hydroxylamine is liquid under ambient conditions, the solvent can be selected to be miscible with hydroxylamine.

[0069] In embodiments, the hydroxylamine may also function as a solvent and can be used to solvate the naphthoquinone. In these embodiments, the hydroxylamine can be used in any desired amount relative to the naphthoquinone, or even in an amount greater than the naphthoquinone.

[0070] The composition may also include one or more solvents. Useful solvents include any solvent in which the combination of naphthoquinone and hydroxylamine is soluble or can be stably suspended. In some embodiments, the solvent or solvent combination can be selected from water-soluble or water-miscible solvents, such as glycol-based solvents, and hydrophobic solvents, such as aromatic solvents, paraffinic solvents, or a mixture of both.

[0071] Exemplary glycol solvents include, but are not limited to, C1-C8 glycols such as ethylene glycol, propylene glycol, diethylene glycol, and triethylene glycol, diethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol, triethylene glycol monomethyl ether, liquid polyethylene glycols, ethers of such glycols such as dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, and low molecular weight polypropylene glycols, and combinations thereof. Commercially available solvents such as Butyl Carbitol and Butyl CELLOSOLVE™, which contain primarily Butyl CARBITOL™, primarily ethylene glycol monobutyl ether, can be used and are available from DOW.

[0072] Other exemplary hydrophobic solvents include heavy aromatic naphtha, toluene, ethylbenzene, and the isomeric hexanes, as well as mixtures of two or more thereof.

[0073] The amount of one or more solvents in the composition containing naphthoquinone and hydroxylamine is not particularly limited. In some embodiments, the concentration of one or more solvents in the composition can be about 10% to 50% by weight of the total composition, for example, about 20% to 50% by weight, or about 25% to 50% by weight, or about 10% to 40% by weight, or about 10% to 30% by weight, or about 20% to 40% by weight, or about 25% to 40% by weight.

[0074] In some embodiments, the composition comprises naphthoquinone in an amount ranging from 5 to 45% by weight, hydroxylamine in an amount ranging from 5 to 45% by weight, and a solvent or solvent combination in an amount ranging from 10 to 90% by weight. In some embodiments, the composition comprises naphthoquinone in an amount ranging from 15 to 35% by weight, hydroxylamine in an amount ranging from 15 to 35% by weight, and a solvent or solvent combination in an amount ranging from 30 to 70% by weight. In some embodiments, the composition comprises naphthoquinone in an amount ranging from 20 to 30% by weight, hydroxylamine in an amount ranging from 20 to 30% by weight, and a solvent or solvent combination in an amount ranging from 30 to 70% by weight. Compositions containing naphthoquinone and hydroxylamine at concentrations higher than the "working" concentration (typically measured in ppm) of naphthoquinone or hydroxylamine may be referred to as "concentrate" or "stock" compositions.

[0075] The compositions of the present disclosure can be prepared using any desired method. In some preparation modes, a solution of naphthoquinone or hydroxylamine with a solvent can be first obtained by the user, such as a commercially available preparation, and then either naphthoquinone or hydroxylamine is added later, such as at some point in the use procedure.

[0076] Compositions comprising a mixture of naphthoquinone and hydroxylamine, optionally with a solvent, can be provided as "storage-stable" compositions, which can then be used in processes for inhibiting the polymerization of monomers. For example, the disclosed method can include preparing a composition of naphthoquinone or hydroxylamine, then storing the composition for a period of time, and then using the composition in a process for inhibiting the polymerization of monomers.

[0077] A method for inhibiting the polymerization of a monomer in a monomer-containing composition can be achieved by adding naphthoquinone and hydroxylamine to a composition containing a polymerizable monomer. Naphthoquinone and hydroxylamine inhibit the polymerization of polymerizable monomers, and when used in combination, they provide greater polymerization inhibition than the inhibitors used individually at corresponding concentrations. In other words, the combination of naphthoquinone and hydroxylamine provides an unexpected (e.g., synergistic) effect of inhibiting monomer polymerization, which provides benefits in various processes in which it is desired to inhibit monomer polymerization.

[0078] As shown herein, naphthoquinone and hydroxylamine, when used together in a monomer-containing composition, can provide unexpected (e.g., synergistic) effects that can eliminate the need for one or more other types of polymerization inhibitors to be used simultaneously with naphthoquinone and hydroxylamine. Other types of polymerization inhibitors that can be excluded from simultaneous use with naphthoquinone and hydroxylamine, or that can be used at very low concentrations, can include nitroxide-, amine oxide-, nitro-, nitroso-, and nitrone-containing compounds.

[0079] For example, if present, any nitroxide-, amine oxide-, nitro-, nitroso-, and nitrone-containing compounds may optionally be present in a working composition with a monomer 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.

[0080] Exemplary nitroxide-containing inhibitors include di-tert-butyl nitroxyl, 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), which may be excluded from the additive compositions of the present disclosure or may not be added to the monomer composition simultaneously with naphthoquinone and hydroxylamine. These types of compounds may be excluded from simultaneous use with naphthoquinone and hydroxylamine, or may be used at very low concentrations, as provided herein.

[0081] Exemplary hydroxylamine-containing polymerization inhibitors include, but are not limited to, 1-hydroxy-2,2,6,6-tetramethylpiperidine (TEMPOH), 1,4-dihydroxy-2,2,6,6-tetramethylpiperidine (HTMPOH), and 1-hydroxy-4-oxo-2,2,6,6-tetramethylpiperidine (OTEMPOH), N,N-diethylhydroxylamine, and N-isopropylhydroxylamine. These types of compounds may be excluded from simultaneous use with naphthoquinone and hydroxylamine, or may be used at very low concentrations, as shown herein.

[0082] Exemplary nitro-containing polymerization inhibitors include, but are not limited to, nitrobenzene, nitrophenol, dinitrophenol, 2,4-dinitro-6-s-butylphenol, 2,4-dinitro-o-cresol, and diphenylpicrylhydrazyl. These types of compounds may be excluded from simultaneous use with naphthoquinone and hydroxylamine, or may be used at very low concentrations, as shown herein.

[0083] Exemplary nitroso-containing polymerization inhibitors include, but are not limited to, nitrosobenzenes, nitrosophenols, dinitrosophenols, dinitrosotoluenes, and nitrosophenyl-hydroxylamines. These types of compounds may be excluded from co-use with naphthoquinones and hydroxylamines, or may be used at very low concentrations, as provided herein.

[0084] Although naphthoquinone and hydroxylamine are preferably used to provide polymerization inhibitor effects without the use of nitroxide-, amine oxide-, nitro-, nitroso-, and nitrone-containing compounds, or optionally with very small amounts of such compounds, the methods of the present disclosure do not exclude the use of monomer-containing compositions pre-treated with nitroxide-, amine oxide-, nitro-, nitroso-, or nitrone-containing compounds, nor do they exclude methods in which such compounds are added at some point after the naphthoquinone and hydroxylamine treatment. For example, the present disclosure contemplates hydrocarbon- and monomer-containing compositions pre-treated with, for example, a nitroxide compound, followed by addition of naphthoquinone and hydroxylamine to the hydrocarbon- and monomer-containing composition after a period in which the nitroxide compound loses its effectiveness. Optionally, the present disclosure also contemplates hydrocarbon- and monomer-containing compositions pre-treated with naphthoquinone and hydroxylamine, followed by subsequent treatment with a compound different from the naphthoquinone and hydroxylamine.

[0085] The polymerizable monomers subjected to polymerization inhibition can contain vinyl or ethylenically unsaturated groups. For example, naphthoquinone and hydroxylamine can be added to a composition containing one or more of the following polymerizable monomers: 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 toluene, and vinyl pyridine.

[0086] 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, naphthoquinone and hydroxylamine can be added to a process stream containing the polymerizable monomer. In the method, the component 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 component can inhibit polymerization of the monomer at any one or more stages of the processing system, minimizing contamination of the equipment.

[0087] Alternatively, the naphthoquinone and hydroxylamine components can be added to a process stream containing compounds capable of forming polymerizable monomers. For example, in a composition containing compounds that can form polymerizable monomers as undesirable by-products, the presence of naphthoquinone and hydroxylamine can inhibit polymerization of the monomers when they are formed as by-products, thus minimizing contamination of equipment.

[0088] In some embodiments, the naphthoquinone and hydroxylamine are introduced into the monomer-containing composition to provide the desired amounts of each reagent in the composition. The naphthoquinone and hydroxylamine can be introduced simultaneously, such as delivered from a composition in which the components are mixed, or can be delivered individually or in partial combination, sequentially, or overlappingly.

[0089] When the naphthoquinone and hydroxylamine are introduced sequentially into the monomer-containing composition, preferably the additions are carried out in a manner that allows the combination of the naphthoquinone and hydroxylamine to provide an unexpected (e.g., synergistic) polymerization inhibitor effect to the composition.

[0090] The introduction of the components into the resulting monomer-containing composition can provide naphthoquinone and hydroxylamine at desired concentrations. For example, at a polymerizable monomer concentration in the range of 50 to 200 ppm, naphthoquinone is present in the composition in an amount in the range of 50 to 500 ppm, and hydroxylamine is present in the composition in an amount in the range of 50 to 500 ppm. In some embodiments, naphthoquinone is present in the composition in an amount in the range of 75 to 400 ppm, and hydroxylamine is present in the composition in an amount in the range of 75 to 400 ppm. In some embodiments, naphthoquinone is present in the composition in an amount in the range of 100 to 300 ppm, and hydroxylamine is present in the composition in an amount in the range of 100 to 300 ppm. In some embodiments, naphthoquinone is present in the composition in an amount in the range of 150 to 250 ppm, and hydroxylamine is present in the composition in an amount in the range of 150 to 250 ppm.

[0091] The term "fouling" refers to the formation of polymers, prepolymers, oligomers, and / or other materials that become insoluble in a stream and / or precipitate from the stream and deposit on equipment under the conditions of operation of the equipment. Similarly, the naphthoquinones and hydroxylamines and compositions of the present disclosure inhibit or reduce such formation and may therefore be referred to as "anti-fouling."

[0092] The naphthoquinone and hydroxylamine components may be used in conjunction with compositions containing polymerizable monomers and "process equipment" associated with the process that may be subject to fouling from monomer polymerization, such as reactors, reactor beds, piping, valves, distillation columns, trays, condensers, heat exchangers, compressors, fans, impellers, pumps, recirculators, intercoolers, sensors, etc. The term also includes sets of these components where multiple components are part of a "system."

[0093] In one preferred method of use, the disclosed composition having naphthoquinone, hydroxylamine, and optional solvent is used in a process involving a distillation column used to separate and purify vinyl monomers. For example, in processes known in the art, ethylbenzene can be subjected to a catalytic dehydrogenation reaction resulting in the formation of styrene. The styrene-containing reaction product also includes other materials, such as aromatic compounds such as toluene and benzene, unreacted ethylbenzene, and polymers. This mixture of compounds is typically fractionally distilled using one or more distillation columns. Heat is typically used to help separate the components within the distillation column. After distillation, the fractionated components can be separated into purer product streams.

[0094] The naphthoquinone and hydroxylamine composition can be introduced into the stream leading from the reaction bed to the distillation column or added directly to the distillation column. The inhibitor composition can be added before heating the monomer composition or while heating the monomer composition in the distillation column. In some embodiments, the naphthoquinone and / or hydroxylamine have a higher boiling point than the desired compound (e.g., a monomer such as styrene) being fed to the distillation column, and during the distillation process, the desired compound is separated from the hydroxylamine due to the temperature difference. In embodiments, the boiling point difference between the desired compound and the naphthoquinone and / or hydroxylamine 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.

[0095] Alternatively, or in addition to adding the inhibitor composition during the distillation process, the inhibitor composition can be added to a distillation effluent stream, such as a purified styrene stream.

[0096] The naphthoquinone and hydroxylamine components can be used in conjunction with a "petroleum product," which refers to any hydrocarbon product obtained from an underground reservoir, any product derived therefrom, or any mixture thereof. The polymerizable monomer can be contained in the petroleum product or chemically derived from the petroleum product. Non-limiting examples of petroleum products include, but are not limited to, crude oil, reduced crude oil, crude distillate, heavy oil, or by-products of petroleum product processing such as bitumen, hydrotreated oil, refined oil, thermal cracking, hydrotreating, or phase separation, or mixtures of two or more of these. A liquid petroleum product is a petroleum product that is substantially liquid at 20°C.

[0097] The naphthoquinone and hydroxylamine components can be added to or present in a "petroleum process stream," which refers to any petroleum product placed within a petroleum processing facility in fluid contact with its interior surface. 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 a petroleum product placed in a settler (separator) or storage vessel for a selected contact period, such as up to two years. The process stream can be substantially dynamic, such as a liquid petroleum product placed in a pipe during transport of the product from a first location to a second location. In some embodiments, the process stream includes one or more additional components associated with petroleum processing, although such components are not particularly limited.

[0098] "Petroleum process equipment" or "petroleum processing unit" refers to a man-made object having an interior surface that includes a metal, and in which one or more petroleum products are in fluid contact with the metal for any period of time and at any temperature, as further determined by context. 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, treating, isolating, distilling, reacting, metering, heating, cooling, or containing one or more petroleum products.

[0099] In embodiments, the compositions comprising naphthoquinone and hydroxylamine are thermally stable and have polymerization inhibitor activity in process streams or other polymerizable monomer-containing compositions at temperatures of from about 20°C to about 400°C, e.g., from about 100°C to 400°C, or from about 100°C to about 350°C, or from about 100°C to 300°C, or from about 100°C to 250°C, or from about 100°C to 200°C, or from about 100°C to 150°C.

[0100] In embodiments, the composition comprising naphthoquinone and hydroxylamine can be introduced into a composition having a polymerizable monomer, such as a liquid petroleum process stream, in a batch, continuous, or semi-continuous manner. In some embodiments, the naphthoquinone and hydroxylamine are introduced manually, while in other embodiments, their introduction is automated. In embodiments, the amount of naphthoquinone and hydroxylamine introduced over a selected unit of time varies depending on the variable composition of the associated process stream. Such variability in dosing can be achieved manually by periodically testing the internal surfaces of the process equipment and then adjusting the amount of composition up or down based on the test results, or automatically by monitoring one or more conditions internal to the petroleum process equipment and signaling the need to apply more composition to the process stream.

[0101] In some embodiments, the naphthoquinone and hydroxylamine are added to a petroleum product that is crude oil, reduced crude oil, heavy oil, bitumen, coker charge, hydrotreater influent, hydrotreater effluent, flash crude oil, light cycle oil, or a diesel or naphtha refinery stream. In embodiments, the compounds are added to petroleum process equipment traditionally associated with the gathering, processing, transporting, or storing one or more of crude oil, reduced crude oil, crude oil distillate, heavy oil, bitumen, coker charge, flash crude oil, light cycle oil, or a diesel or naphtha refinery stream, including piping and related infrastructure used to fluidly connect process equipment items to facilitate processing of the process streams located therein.

[0102] Equipment containing a polymerizable monomer-containing composition treated with naphthoquinone and hydroxylamine can reduce or eliminate fouling of the interior surfaces of the equipment. In embodiments, fouling is measured as a relative increase in solids retention in the treated composition compared to the solids retention in the untreated composition over the same period. In embodiments, fouling is measured as a relative decrease in the weight or volume of sediment resulting from a selected period of contact of the treated process stream within the relevant process equipment item compared to the same period of contact of the process equipment with the corresponding untreated process stream. Stated differently, the reduction in fouling is the relative decrease in the measured weight or volume of solids deposited or precipitated from process equipment contacted with the treated process stream over a selected period of time when compared to the weight or volume of solids deposited or precipitated from the untreated process stream over the same period of time.

[0103] Naphthoquinones and hydroxylamines can also inhibit undesired polymerization and fouling of process equipment or retard polymerization of resins and compositions containing ethylenically unsaturated species in primary fractionation processes, light ends fractionation, non-aromatic vinyl halide fractionation, process gas compression, dilution steam systems, alkali towers, quench water towers, butadiene extraction, propane dehydrogenation, diesel and petroleum fuel stabilization, olefin metathesis, styrene purification, and hydroxyhydrocarbon purification.

[0104] The naphthoquinone and hydroxylamine can be added at any point in the process, at one or more locations. For example, the antifouling composition can be added directly to the intercooler or compressor, or upstream of the intercooler or compressor. The naphthoquinone and hydroxylamine can be added continuously or intermittently to the process equipment as needed to inhibit or reduce fouling.

[0105] The naphthoquinone and hydroxylamine can be introduced into the desired system by any suitable method. For example, they may be added neat or in a diluted solution. In some embodiments, the composition containing naphthoquinone and hydroxylamine can be applied as a solution, emulsion, or dispersion that is sprayed, dripped, poured, or injected into the desired opening in the system, or into process equipment or process condensate. In some embodiments, the composition can be added with cleaning oil or tempered water.

[0106] After introducing the composition into the process equipment, the treated process equipment may be observed to have less buildup on the equipment than process equipment without the addition of the composition. The reduction or inhibition of fouling may be assessed by any known method or test. In some embodiments, the reduction or inhibition of fouling may be assessed by measuring the time it takes for samples to gel with and without the antifoulant composition. See the Experimental section for further details. [Example]

[0107] The following illustrative, non-limiting examples are provided: Examples 1-5, 7-10, and 12-14 detail the preparation of components of experimental compositions or provide formulations for comparative purposes.

[0108] The following abbreviations are used in the following examples and in connection with this disclosure generally: 1,4-naphthoquinone (1,4-NQ), 1,2-naphthoquinone (1,2-NQ), hydroxylamine (HA), N,N-diethylhydroxylamine (DEHA), piperidinol (Pipol), N-isopropylhydroxylamine (IPHA), N,N-bis(2-hydroxypropylhydroxylamine) (HPHA), N,N-bis(2-hydroxy-2-phenylethyl)hydroxylamine (BHPhEHA), styrene, butadiene (BD), isoprene, methyl methacrylate methacrylate (MMA), dibenzylhydroxylamine (DBzHA), 4-hydroxy-2,2,6,6-trimethylpiperidinoxy (HTMPO), 2,4-dinitro-6-sec-butylphenol (DNBP), 7-phenyl quinone methide (QMPh); comparative example (CE).

[0109] Example 1: Styrene Polymerization with 400 ppm DEHA Treatment (CE)

[0110] A 200 g styrene solution containing 400 ppm DEHA was prepared. The 4-tert-butylcatechol stabilizer in the styrene solution was removed immediately prior to use in the treatment composition. An alumina column was used to remove the stabilizer. The reaction mixture was placed in a 1 L three-neck round-bottom flask. A magnetic follower was added to the flask, after which a water-cooled condenser and thermocouple were attached to two of the three necks. A stream of nitrogen gas was passed through the gas line on the third neck of the reaction flask into the reaction mixture to remove dissolved oxygen and purge the flask of atmospheric oxygen. The loaded flask was placed on a heating block preheated to 115°C. The start of the reaction kinetics study was designated when the temperature of the reaction solution reached 115°C. At this point, a sample was taken from the reaction mixture and diluted with toluene, and the polymer concentration was determined by a proprietary method. After 20 minutes and every 20 minutes thereafter, samples were taken from the flask, and the amount of polymer was determined as described above. The results are shown in Table 1 and Figure 1.

[0111] Example 2: Styrene polymerization with 400 ppm 1,4-NQ treatment (CE)

[0112] A solution of 200 g of freshly purified styrene with 400 ppm 1,4-naphthoquinone was prepared. This solution was used to determine the effectiveness of 1,4-naphthoquinone as a polymerization inhibitor using the procedure of Example 1. The results are shown in Table 1 and Figure 1.

[0113] Example 3: Styrene polymerization with 200 ppm DEHA and 200 ppm 1,4-NQ treatment

[0114] Using the procedure of Example 1, a solution containing 200 g of styrene, 200 ppm DEHA, and 200 ppm d1,4-naphthoquinone was prepared to determine the performance of the two polymerization inhibitors used in combination. The results are shown in Table 1 and Figure 1. Using the combination of 1,4-NQ and DEHA, inhibition of styrene polymerization was greater than would be expected given the results obtained when 1,4-NQ and DEHA were used individually at the same total concentration. For comparison purposes, the "expected" level of polymerization inhibitor activity (without testing the inventive combination of 1,4-NQ and DEHA) is 4.195 ((3.45 + 4.94) / 2)% (w / w) polymer at 100 minutes, based on the individual results. However, the inventive combination of 1,4-NQ and DEHA (used at 200 ppm each) at 100 minutes showed a polymerization level of 0.58% ((w / w) polymer), a significant and unexpected reduction in polymerization compared to the predicted value of 4.195. This polymerization level of 0.58 is a reduction of approximately 86% compared to the predicted average of 4.195.

[0115] Example 4: Styrene Polymerization with 400 ppm DNBP (CE)

[0116] A composition of 200 g of freshly purified styrene and 400 ppm DNBP was prepared and tested for inhibitor kinetics according to the procedure of Example 1. The results are shown in Table 1 and Figure 1.

[0117] [Table 1]

[0118] Example 5: Styrene Polymerization with 400 ppm Piperidinol Treatment (CE)

[0119] A solution of 200 g of freshly purified styrene and 400 ppm piperidinol was prepared and tested for inhibitor kinetics using the procedure of Example 1. The results are shown in Table 2 and Figure 2.

[0120] Example 6: Styrene polymerization with 200 ppm piperidinol and 200 ppm 1,4-NQ treatment

[0121] A solution of 200 g of styrene with 200 ppm piperidinol and 200 ppm d1,4-NQ was prepared, and the performance of the two polymerization inhibitors used in combination was determined according to the procedure of Example 1. The results are shown in Table 2 and Figure 2. Using the combination of 1,4-NQ and piperidinol, the inhibition of styrene polymerization was greater than would be expected given the results obtained when 1,4-NQ and piperidinol were used individually at the same total concentrations.

[0122] [Table 2]

[0123] Example 7: Styrene polymerization with 400 ppm DBzHA treatment (CE)

[0124] A solution of 200 g of freshly clarified styrene with DBzHA polymerization inhibitor dosed in the solution at a concentration of 400 ppm was tested for the kinetics of the polymerization inhibitor reaction using the procedure of Example 1. The results are shown in Table 3 and Figure 3.

[0125] Example 8: Styrene polymerization with 200 ppm DBzHA and 200 ppm 1,4-NQ treatment

[0126] A solution of 200 g of styrene, 200 ppm of DBzHA, and 200 ppm of 1,4-NQ was prepared, and the performance of the two polymerization inhibitors used in combination was determined according to the procedure of Example 1. The results are shown in Table 3 and Figure 3. Using the combination of 1,4-NQ and DBzHA, the inhibition of styrene polymerization was greater than would be expected given the results obtained when 1,4-NQ and DBzHA were used individually at the same total concentrations.

[0127] [Table 3]

Claims

1. 1. A method for reducing the formation of polymers in a monomer-containing composition, said method comprising: adding a component to a composition comprising a polymerizable monomer or a compound capable of forming a polymerizable monomer, said component comprising: Naphthoquinone, hydroxylamine, The hydroxylamine has the formula I: HO—NR １ R ２ [In the formula, R １ and R ２ at least one or both of R １ or R ２ is —H when it is not a carbon-containing group; or Formula II: 【Chemical 1】 wherein X is —(CHR ５ ) ｗ - and R ５ is -H, R ３ , and R ４ and R ３ is selected from —H and alkyl, and R ４ is selected from —H and —OH; y is 0 or an integer ranging from 1 to 3; z is 0 or an integer ranging from 1 to 3; and w is an integer ranging from 1 to 4; The method wherein the naphthoquinone and hydroxylamine reduce the formation of polymers in the composition.

2. R １ is selected from (i) a C1 to C12 alkyl group, (ii) a C1 to C8 alkyl group, or (iii) a C1 to C6 alkyl group, and (i) to (iii) are linear, branched, or cyclic alkyl groups, or combinations thereof; R ２ is selected from (iv) —H and a C1 to C12 alkyl group, (v) —H and a C1 to C8 alkyl group, or (vi) —H and a C1 to C6 alkyl group, wherein the alkyl groups in (iv) through (vi) are linear, branched, or cyclic, or a combination thereof, and any one or more alkyl groups in (i) through (vi) are optionally substituted with one or more hydroxyl groups.

3. R １ is selected from (A) methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, cyclopentyl, isopentyl, neopentyl, hexyl, cyclohexyl, 1-, 2-, and 3-methylbutyl, 1,1-, 1,2-, or 2,2-dimethylpropyl, 1-ethylpropyl, 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, and methylcyclopentyl; R ２ 3. The method of claim 2, wherein: is selected from (A) and —H, wherein any of (A) is optionally substituted with one or more hydroxyl groups.

4. The compound of formula I is N,N-dimethylhydroxylamine, N-methyl-N-ethylhydroxylamine, N-methyl-N-propylhydroxylamine, N-methyl-N-isopropylhydroxylamine, N-methyl-N-propylhydroxylamine, N-methyl-N-butylhydroxylamine, N-methyl-N-isobutylhydroxylamine, N-methyl-N-t-butylhydroxylamine, N-,N-diethylhydroxylamine, N-ethyl-N-propylhydroxylamine, N-ethyl-N-isopropylhydroxylamine, N-ethyl-N-propylhydroxylamine, N-ethyl 4. The method of claim 3, wherein the hydroxylamine is selected from the group consisting of N-butylhydroxylamine, N-ethyl-N-isobutylhydroxylamine, N-ethyl-N-t-butylhydroxylamine, N-,N-dipropylhydroxylamine, N-,N-diisopropylhydroxylamine, N-propyl-N-butylhydroxylamine, N-isopropyl-N-butylhydroxylamine, N-propyl-N-isobutylhydroxylamine, N-propyl-N-t-butylhydroxylamine, N-isopropyl-N-isobutylhydroxylamine, and N-isopropyl-N-t-butylhydroxylamine.

5. [0013] The compound of formula I is N-methylhydroxylamine, N-ethylhydroxylamine, N-propylhydroxylamine, N-isopropylhydroxylamine, N-butylhydroxylamine, N-isobutylhydroxylamine, N-t-butylhydroxylamine, N-sec-butylhydroxylamine, N-pentylhydroxylamine, N-cyclopentylhydroxylamine, N-isopentylhydroxylamine, N-neopentylhydroxylamine, N-hexylhydroxylamine, N-cyclohexylhydroxylamine, N-1-, 2-, and 3-methylbutylhydroxylamine, 4. The method of claim 3, wherein the hydroxylamine is selected from the group consisting of N-1,1-, 1,2-, or 2,2-dimethylpropylhydroxylamine, N-1-ethyl-propylhydroxylamine, 1-, 2-, 3-, or 4-methylpentylhydroxylamine, N-1,1-, 1,2-, 1,3-, 2,2-, 2,3-, or 3,3-dimethylbutylhydroxylamine, N-1- or 2-ethylbutylhydroxylamine, N-1-ethyl-1-methyl-propylhydroxylamine, and N-1,1,2- or 1,2,2-trimethylpropylhydroxylamine, and N-methylcyclopentylhydroxylamine.

6. The compound of formula I is selected from the group consisting of N-hydroxymethylhydroxylamine, N-1- or 2-hydroxyethylhydroxylamine, N-1-, 2-, or 3-hydroxypropylhydroxylamine, N-1- or 2-hydroxypropylhydroxylamine, N-1-, 2-, 3-, or 4-hydroxybutylhydroxylamine, N-1-, 2-, or 3-hydroxyisobutylhydroxylamine, N-1-, 2-, or 3-hydroxysec-butylhydroxylamine, N-2-hydroxy-t-butylhydroxylamine, and N-1-, 2-, 3-, 4, or 5-N-hydroxypentylhydroxylamine, or N,N-bis(hydroxymethyl)hydroxylamine, N 4. The method of claim 3, wherein the hydroxylamine is selected from the group consisting of N,N-bis(1- or 2-hydroxyethyl)hydroxylamine, N,N-bis(1-, 2-, or 3-hydroxypropyl)hydroxylamine, N,N-bis(1- or 2-hydroxypropyl)hydroxylamine, N,N-bis(1-, 2-, 3-, or 4-hydroxybutyl)hydroxylamine, N,N-bis(1-, 2-, or 3-hydroxyisobutyl)hydroxylamine, N,N-bis(1-, 2-, or 3-hydroxysecbutyl)hydroxylamine, N,N-bis(2-hydroxy-t-butyl)hydroxylamine, and N,N-bis(1-, 2-, 3-, 4, or 5-N-hydroxypentyl)hydroxylamine.

7. R is the carbon-containing group having 1 to 12 carbon atoms １ and R ２ one or both of R １ and R ２ wherein one or both of the groups have the formula: 【Chemistry 2】 [In the formula, R ６ is independently selected from the group consisting of —H, —OH, and alkyl; v is an integer ranging from 1 to 6; R ７ is independently selected from the group consisting of -H, -OH, and alkyl, and q is an integer ranging from 1 to 5.

8. formula: 【Chemistry 3】 In this case, R ６ is independently selected from —H and —OH, v is an integer ranging from 1 to 4, and R ７ is —H, q is 5, and said compound is optionally selected from the group consisting of benzylhydroxylamine, N-phenethyl-hydroxylamine, N-(3-phenyl-propyl)-hydroxylamine, N-(4-phenyl-butyl)-hydroxylamine, N-(5-phenyl-pentyl)-hydroxylamine, N-(6-hexyl-propyl)-hydroxylamine, N-(3-phenyl-2-methyl-propyl)-hydroxylamine, and N-(4-phenyl-3-methyl-butyl)-hydroxylamine; selected from the group consisting of dibenzylhydroxylamine, N,N-bis(phenethyl)hydroxylamine, N,N-bis(3-phenylpropyl)hydroxylamine, N,N-bis(4-phenyl-butyl)-hydroxylamine, N,N-bis(5-phenyl-pentyl)-hydroxylamine, N,N-bis(6-hexyl-propyl)-hydroxylamine, N,N-bis(3-phenyl-2-methyl-propyl)-hydroxylamine, and N,N-bis(4-phenyl-3-methyl-butyl)-hydroxylamine; selected from the group consisting of N-(2-phenyl-1-hydroxyl-ethyl)-hydroxylamine, N-(3-phenyl-2-hydroxyl-propyl)-hydroxylamine, N-(4-phenyl-2-hydroxyl-butyl)-hydroxylamine, N-(5-phenyl-2-hydroxyl-pentyl)-hydroxylamine, N-(6-hexyl-2-hydroxyl-propyl)-hydroxylamine; 8. The method of claim 7, wherein the hydroxylamine is selected from the group consisting of N,N-bis(2-phenyl-1-hydroxyl-ethyl)hydroxylamine, N,N-bis(3-phenyl-2-hydroxyl-propyl)-hydroxylamine, N,N-bis(4-phenyl-2-hydroxyl-butyl)-hydroxylamine, N,N-bis(5-phenyl-2-hydroxyl-pentyl)-hydroxylamine, and N,N-bis(6-hexyl-2-hydroxyl-propyl)-hydroxylamine.

9. The method according to any one of claims 1 to 8, wherein the naphthoquinone is 1,4-naphthoquinone, 1,3-naphthoquinone, or 1,2-naphthoquinone.

10. 10. The method of any one of claims 1 to 9, wherein the naphthoquinone is an aminated naphthoquinone polymerization inhibitor selected from the group consisting of 2-amino, 1,4-naphthoquinone, 2,3-diamino, 1,4-naphthoquinone, 2-amino, 1,3-naphthoquinone, 4-amino, 1,3-naphthoquinone, 2,4-diamino, 1,3-naphthoquinone, 3-amino, 1,2-naphthoquinone, 4-amino, 1,2-naphthoquinone, and 3,4-diamino, 1,3-naphthoquinone.

11. The method of any one of claims 1 to 10, wherein the polymerizable monomer comprises a vinyl or ethylenically unsaturated group.

12. 12. The method of claim 11, 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, vinyl toluene, and vinyl pyridine.

13. The method of any one of claims 1 to 12, wherein the composition comprises one or more non-polymerizable hydrocarbons.

14. 14. The method of any one of claims 1 to 13, wherein the naphthoquinone is present in the composition in an amount ranging from 50 to 500 ppm, the hydroxylamine is present in the composition in an amount ranging from 50 to 500 ppm, optionally the naphthoquinone is present in the composition in an amount ranging from 75 to 400 ppm, the hydroxylamine is present in the composition in an amount ranging from 75 to 400 ppm, optionally the naphthoquinone is present in the composition in an amount ranging from 100 to 300 ppm, the hydroxylamine is present in the composition in an amount ranging from 100 to 300 ppm, optionally the naphthoquinone is present in the composition in an amount ranging from 150 to 250 ppm, and the hydroxylamine is present in the composition in an amount ranging from 150 to 250 ppm.

15. The method of any one of claims 1 to 14, wherein the adding is carried out during the purification or processing of one or more hydrocarbon components of the composition.

16. 16. The method of claim 15, wherein the processing of the one or more hydrocarbons comprises a distillation step.

17. The method of any one of claims 1 to 16, carried out before storing or transporting the composition.

18. 18. The method of any one of claims 1 to 17, wherein the naphthoquinone is used at a first concentration and the hydroxylamine is used at a second concentration, the first concentration plus the second concentration being a total concentration, and wherein the combination of the naphthoquinone and hydroxylamine together provides a level of polymer formation that is less than or average of the level of polymer formation observed when either the naphthoquinone or the hydroxylamine is used alone at said total concentration.

19. 19. The method of claim 18, wherein the combination of the hydroxylamine and naphthoquinone provides a reduction in polymerization of 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, or 80% or more, for example up to about 90% or more, compared to the average or compared to either the naphthoquinone or the hydroxylamine used individually in total concentration, or a reduction in a percentage amount within any of these ranges.

20. 1. An additive composition for inhibiting the polymerization of a monomer, said composition comprising: Naphthoquinone, hydroxylamine, The hydroxylamine has the formula I: HO—NR １ R ２ [In the formula, R １ and R ２ at least one or both of R １ or R ２ is —H when it is not a carbon-containing group; or Formula II: 【Chemistry 4】 wherein X is —(CHR ５ ) ｗ - and R ５ is -H, R ３ , and R ４ and R ３ is selected from —H and alkyl, and R ４ is selected from -H and -OH; y is 0 or an integer ranging from 1 to 3; z is 0 or an integer ranging from 1 to 3; and w is an integer ranging from 1 to 4.

21. 21. The composition of claim 20, further comprising an organic solvent.

22. the naphthoquinone is in an amount ranging from 5 to 45% (by weight); the hydroxylamine is in an amount ranging from 5 to 45% (by weight); and 22. The composition of claim 21, wherein the organic solvent is present in an amount ranging from 10 to 90% by weight.

23. the naphthoquinone is in an amount ranging from 15 to 35% (by weight); the hydroxylamine is in an amount ranging from 15 to 35% (by weight); and 23. The composition of claim 22, wherein the organic solvent is present in an amount ranging from 30 to 70% by weight.

24. Use of a composition according to any one of claims 20 to 23 for reducing the formation of polymers in a composition.

25. Use of a composition according to any one of claims 20 to 23 for a hydrocarbon refining or hydrocarbon purification process.

26. Use of a composition according to any one of claims 20 to 23 for storing or transporting a hydrocarbon composition.

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