Compositions comprising nitrogen oxide inhibitors, quinone methide retarder and amine stabilizers for inhibiting monomer polymerization

Abstract

Compositions and methods for inhibiting the polymerization of monomer (e.g., styrene) compositions are described, the methods using N-O polymerization inhibitors, quinone methide polymerization retarders, and amine stabilizers having primary and / or secondary amine groups. In the mixture, the amine-based stabilizer can prevent antagonism and can provide greater anti-polymerization activity. In turn, the mixture inhibits plant fouling and improves the purity of the monomer stream.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Patent Application Serial No. 62 / 697,715, filed on July 13, 2018, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] The present invention relates to combinations of amine stabilizer compounds with polymerization inhibitors and retarders and their use in inhibiting premature polymerization of monomers. Background Art

[0004] Ethylenically unsaturated monomers, for example vinyl aromatic monomers such as styrene, may be present in processing streams or refined products made by various chemical industrial processes. However, these monomer types may undesirably polymerize by free radical polymerization, especially at high temperatures. As a result, solid deposits of polymers may form on the surfaces of process equipment during industrial manufacturing, processing, handling or storage. The resulting polymers may be problematic and lead to equipment "fouling" and product contamination. Therefore, this may require treatment equipment to remove the polymer, or may require treatment steps to remove the polymer from the composition stream or stored composition. These undesirable polymerization reactions result in a loss of production efficiency because they consume expensive reagents and may require additional steps to clean the equipment and / or remove the undesirable polymer. Undesirable polymerization reactions are particularly problematic in compositions with vinyl aromatic monomers.

[0005] In order to minimize undesired polymerization reactions, compounds that act as anti-polymerization agents are often added to process streams or stored compositions.Two classes of anti-polymerization agents have been developed to minimize unwanted polymerization reactions: polymerization inhibitors and polymerization retarders.

[0006] Polymerization inhibitors inhibit the occurrence of polymerization reactions. However, these compounds are usually consumed quickly. For example, in emergency situations due to mechanical or processing problems, and in situations where it is not possible to add more inhibitor, the previously added inhibitor will be consumed quickly. Subsequently, the unwanted polymerization reaction will then occur quickly.

[0007] Examples of polymerization inhibitors known in the art include dialkylhydroxylamines, such as hydroxypropylhydroxylamine (HPHA), and stable nitrogen oxide free radicals. Other inhibitors include N,N'-dialkylphenylenediamines, N,N'-diarylphenylenediamines, N-aryl-N'-alkylphenylenediamines. Quinone diimide compounds are also another class of inhibitors.

[0008] Polymerization retarders slow down the rate of polymerization but are not as effective as polymerization inhibitors. However, polymerization retarders are generally not consumed as quickly as polymerization inhibitors, making them more useful in emergency shutdown operations.

[0009] First, blockers such as sulfur and dinitrophenol (DNP) compounds such as 2,6-dinitrophenol, 2,4-dinitrocresol, and 2-sec-butyl-4,6-dinitrophenol (DNBP) were used. However, DNP and sulfur blockers release NO X and SO X Gases, thus making their use problematic. In addition, DNP-based retarders are highly toxic, which is a concern during handling.

[0010] One class of compounds intended to be used as safe alternatives to DNP blockers is based on quinone methide chemistry. Under static conditions, quinone methides slow the rate of polymer formation and do not require frequent refeeding into the process stream. However, some quinone methide compounds do not exhibit good stability. Examples of quinone methide compounds are described in U.S. Patent Nos. 4,003,800, 5,583,247, and 7,045,647.

[0011] Technical challenges regarding polymerization inhibitors and retarders, as well as stability and safety issues, remain in this technical field. In addition, the present disclosure is associated with the discovery that, although it is desirable to combine polymerization inhibitors and retarders in the same composition, the mixtures often suffer from compatibility issues, which reduce the effectiveness of the polymerization inhibitor and retarder activity. Summary of the invention

[0012] Disclosed herein are compositions and methods for inhibiting the polymerization of monomers in compositions that include or can form monomers. The compositions and methods disclosed herein use polymerization inhibitors, polymerization retarders and amine compounds, wherein the amine compounds are used as stabilizers, and when used together, the stabilizers improve the functions of the polymerization inhibitors and stabilizers. The use of the amine stabilizers of the present invention can not only hinder the antagonism observed when the polymerization inhibitors and retarders are combined, but also can make the mixture have greater anti-polymerization activity than the inhibitors and retarders observed without the use of amine stabilizers. The mixture of inhibitors, retarders and amine stabilizers shows significant activity in inhibiting the unwanted polymerization of monomers such as styrene in various applications, such as in synthesis, refining or storage. Polymer contamination is reduced and other processing steps can be avoided. In addition, by inhibiting polymerization, the mixture can minimize the accumulation ("fouling") of unwanted polymers on processing or storage equipment, and thus reduce the maintenance cost of such equipment.

[0013] In an embodiment, the present invention provides a composition for inhibiting the polymerization of monomers, the composition comprising a polymerization inhibitor having NO functionality, a polymerization retarder being a quinone methide; a stabilizer compound having a primary amine group, a secondary amine group, or both. Advantageously, these components can be combined in a single package formulation, wherein the amine stabilizer reduces or eliminates any antagonistic effect of the inhibitor and the retarder acting on each other in the mixture.

[0014] Exemplary amine stabilizers include alkylated amines, particularly amines having boiling points greater than 100° C. or greater than 150° C. Amine stabilizers can stabilize polymerization inhibitor materials containing nitrogen oxide groups, such as 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO).

[0015] In an embodiment, the present invention provides the use of a polymerization inhibitor having a N-O bond, a retarder compound which is a quinone methide, and a stabilizer compound having a primary or secondary amine group, which is used to inhibit the polymerization of monomers in a composition, for the synthesis, refinement or purification of polymerizable monomers, or for the storage or transportation of polymerizable monomers.

[0016] In an embodiment, the present invention provides a method for preparing a composition for inhibiting monomer polymerization. One method of making the composition involves obtaining a first composition, the first composition comprising (i) an inhibitor compound having a NO portion (ii) a stabilizer compound having a primary or secondary amine group, and then adding (iii) a retarder compound that is itself a quinone methide to the first composition. Another method of making the composition involves obtaining a first composition, the first composition comprising (i) a retarder compound that is itself a quinone methide (ii) a stabilizer compound that has a primary or secondary amine group, and then adding (iii) an inhibitor compound having a NO bond to the first composition. Yet another method of making the composition involves simultaneously or sequentially combining (i) a retarder compound that is itself a quinone methide (ii) an inhibitor compound having a NO bond, and (iii) a stabilizer compound having a primary or secondary amine group to form a composition for inhibiting monomer polymerization.

[0017] In an embodiment, the present invention also provides a method for inhibiting polymerization of a monomer in a composition containing a monomer. The method comprises one or more of the following steps: adding a component comprising an inhibitor compound having a N-O bond, a retarder compound which is a quinone methide, and a stabilizer compound having a primary or secondary amine group to a composition comprising a polymerizable monomer or a composition capable of forming a polymerizable monomer, wherein the first composition inhibits polymerization of the polymerizable monomer. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1is a graph of the formation of polystyrene over time in a styrene monomer solution in the presence of a polymerization retarder and inhibitor, respectively, co-injected or introduced.

[0019] Figure 2 is a graph of polystyrene formation over time in a styrene monomer solution in the presence of polymerization retarders and inhibitors introduced individually or in the presence of an amine stabilizer. DETAILED DESCRIPTION

[0020] Although the present disclosure provides references to preferred embodiments, those skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the present invention. References to various embodiments do not limit the scope of the appended claims. In addition, any examples set forth in this specification are not intended to limit and merely set forth some of the many possible embodiments of the appended claims.

[0021] Additional advantages and novel features of the 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 compositions including polymerization inhibitors, polymerization retarders, and amine stabilizers for use in compositions to inhibit unwanted polymer formation. The amine stabilizers can improve the function of the inhibitor and stabilizer compounds in the mixture and provide better anti-polymerization activity. The present disclosure also provides methods of using polymerization inhibitors, polymerization retarders, and amine stabilizers in methods of inhibiting polymerization of monomers in compositions containing monomers, such as compositions containing vinyl aromatic monomers.

[0023] In the presence of polymerizable monomers, a "polymerization inhibitor" inhibits the formation of polymers from these monomers during the induction time. After the induction time has elapsed, the formation of polymer occurs at substantially the same rate as in the absence of the polymerization inhibitor.

[0024] A "polymerization retardant" does not exhibit an induction time, but rather, upon addition to a polymerizable monomer composition, reduces the rate at which polymer is formed relative to the rate at which it would form in the absence of the composition.

[0025] In contrast to polymerization retarders, polymerization inhibitors are generally consumed rapidly. Although polymerization retarders slow down the rate of polymerization reactions, they are not as effective as polymerization inhibitors. However, polymerization retarders are generally not consumed as rapidly as polymerization inhibitors.

[0026] Polymerization inhibitors and polymerization retarders are generally considered "anti-polymerizers" and are compounds that inhibit or reduce the formation of polymers from one or more free radically polymerizable compounds.

[0027] "Stabilizer" refers to a compound that can improve the function of polymerization inhibitors and retarders when used in combination (compared to a composition that does not include the stabilizer). Without being limited to a particular theory or mechanism of action of the stabilizer, the stabilizer can reduce the antagonistic effect of the polymerization inhibitor and retarder on each other when combined, or enhance the function of either or both of the polymerization inhibitor and / or retarder. For example, the stabilizer can enhance the ability of the inhibitor and / or retarder to inhibit and / or retard polymerization, respectively, or can enhance the functional life of the inhibitor and / or retarder, thereby extending the induction time of the inhibitor, etc. Alternatively, the amine stabilizer can be referred to as an "enhancer" or "additive" for a composition containing a polymerization inhibitor and a retarder, or simply as an "amine compound."

[0028] Aspects of the present disclosure provide a composition for inhibiting monomer polymerization, the composition comprising an inhibitor compound having a NO functional group, a retarder compound which is itself a quinone methide; and an amine stabilizer compound having a primary or secondary amine group. The composition comprising these components (and any one or more optional components) can be in a desired form, such as in a liquid form, a dry form, or as a suspension or dispersion. The inhibitor, the retarder, and the amine stabilizer can be in a desired physical state in the composition, such as in a dissolved state, in a partially dissolved state, in a suspended state, or in a dry mixture. Similarly, the inhibitor, the retarder, and the amine stabilizer can be in a desired physical state in the composition, such as optionally in a particle form. If one or more components are in a particle form, the particles can be optionally described according to particle size (e.g., particles of a particle size range) and / or shape. With the physical properties of each compound known, the form of the composition and the state of the components therein can be selected by selecting inhibitors, retarder, and stabilizer compounds. 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 solvents or solvent mixtures, or other excipient compounds such as surfactants, dispersants, etc. The state of the composition and the components therein may also be affected by temperature, and the properties of the composition may optionally be described at a specific temperature (e.g., at a storage temperature such as 5°C or lower), at room temperature (25°C), or at the temperature used for monomer synthesis and / or processing (e.g., about 100°C or higher, about 150°C, about 175°C, etc.).

[0029] Compositions including inhibitors, retarders, and stabilizer compounds may optionally include other components in the composition (e.g., described as a composition "comprising" an inhibitor, retarder, and stabilizer). For example, such compositions may include other components, such as solvents, surfactants, dispersants, and the like. If optional components are present in the composition, they may be described in terms of weight relative to one or more of the inhibitor, retarder, and stabilizer compounds in the composition. The optional components may be present in an amount greater than the weight of any one of the inhibitor, retarder, or stabilizer, or less than the amount of any one of the inhibitor, retarder, or stabilizer, or the total amount of the inhibitor, retarder, and stabilizer.

[0030] As used herein, the terms "optional" or "optionally" mean that the subsequently described object (e.g., compound), event (e.g., process step), or circumstance can but need not occur, and that the description includes instances where the object, event, or circumstance occurs and instances where it does not.

[0031] The compositions of the present disclosure may include those listed compounds, and optionally may include other components in the composition, but in very small amounts (e.g., described as a composition "consisting essentially of the listed components"). For example, such compositions may include one or more other components, but the content of the components is no more than about 1% (wt), about 0.5% (wt), or about 0.1% (wt) of the total composition. Compositions consisting essentially of inhibitors, retarders, stabilizers, and solvents may optionally include one or more other components, but the amount of the components is less than about 1% (wt) of the total composition. In a composition "consisting of the listed components", there are no other measurable amounts of components other than the listed components.

[0032] Likewise, in some embodiments, the chemistry of the disclosed compounds, including amine stabilizers, polymerization inhibitors, and polymerization retarders, can be described in terms of compounds that are "consisting of certain atoms or certain chemical groups." For example, a compound consisting of carbon (C), hydrogen (H), and nitrogen (N) would not have any other types of atoms besides C, H, and N. As another example, a compound consisting of a hydrocarbon group and a primary amine group would have no other chemical groups besides these.

[0033] As used herein, the terms "substantially" and "consisting essentially of" used in describing embodiments of the present disclosure to modify, for example, the type or amount of an ingredient in a composition, a property, a measurable amount, a method, a position, a value, or a range, refer to changes in a manner that invalidates the intended composition, property, amount, method, position, value, or range without affecting all of the listed compositions, properties, amounts, methods, positions, values, or ranges thereof. Examples of intended properties include, by way of non-limiting example only, dispersibility, stability, rate, solubility, etc.; intended values ​​include weight of added components, concentration of added components, etc. Effects acting on the modified process include effects caused by changes in the type or amount of materials used in the process, changes in machine settings, effects of environmental conditions on the process, etc. (where the manner or degree of the effects does not negate one or more of the intended properties or results) and similar approximate considerations. Where modified by the terms "substantially" or "consisting essentially of", the appended claims include equivalents of these types and amounts of materials.

[0034] As used herein, the term "about" used in describing the embodiments of the present disclosure to modify, for example, the amount of ingredients in the composition, concentration, volume, processing temperature, processing time, yield, flow rate, pressure and similar values, as well as ranges thereof, refers to changes in numerical quantities that may occur, for example, by typical measurements and processing procedures for preparing compounds, compositions, concentrates or using formulations; by inadvertent errors in these procedures; by differences in the manufacture, source or purity of the starting materials or ingredients used to carry out the method, and similar close considerations. The term "about" also encompasses amounts that differ from a specific starting concentration or mixture due to aging of the formulation, and amounts that differ from a specific starting concentration or mixture due to mixing or processing the formulation. When modified with the term "about", the attached claims include equivalents of these amounts. Further, unless the context clearly limits, when "about" is used to describe any range of values, such as "about 1 to 5", the enumeration means "1 to 5" and "about 1 to about 5" and "1 to about 5" and "about 1 to 5".

[0035] Some R groups in the formula of the present disclosure may include hydrocarbon-containing groups such as alkyl, the alkyl including linear, branched and cyclic alkyl, aryl, alkylaryl (e.g., phenyl-propyl), arylalkyl (e.g., propyl-phenyl) and combinations thereof. Cyclic alkyl or aryl may have a fused structure, such as decahydronaphthalene, naphthalene, tetrahydroanthracene, anthracene, etc. In some embodiments, these hydrocarbon groups may be defined by the number of carbon atoms in the group, such as 1 to 22 carbon atoms, 1 to 18 carbons, 1 to 15 carbons, 1 to 12 carbons, 1 to 9 carbons or 1 to 6 carbons. The compositions and methods of the present disclosure include or use polymerization inhibitors including N-O bonds. In use, the polymerization inhibitor can generate stable free radicals on oxygen atoms. Exemplary polymerization inhibitors with N-O bonds include nitrogen oxides, amine oxides, hydroxylamines, nitro groups, nitroso groups and nitrogen-containing compounds.

[0036] In some embodiments, the polymerization inhibitor is a compound containing nitrogen oxide or hydroxylamine. In the method of the present disclosure, the nitrogen oxide free radical can capture the propagating monomer free radical in the thermally unstable substance and inhibit polymerization. The nitrogen oxide group, which can also be called an amine-N-oxide group, is a functional group including a NO bond and a side group connected to nitrogen. The nitrogen oxide (nitroxyl) free radical is an oxygen-centered free radical with free electrons delocalized on the NO bond. The polymerization inhibitor containing nitrogen oxides can include a NO resonance structure that contributes to the stability of the nitrogen oxide free radical.

[0037]

[0038] Nitrogen oxide containing polymerization inhibitors can have a fairly long useful life, which allows them to act as persistent free radicals. Nitrogen oxide and hydroxylamine compounds can include the following chemistries:

[0039]

[0040] Where X is an unpaired electron or H.

[0041] Exemplary nitrogen oxide-containing polymerization inhibitors include compounds of Formulas I and II:

[0042]

[0043] Where R 1 , R 2 , R 3 and R 4 (Formula I) and R 1 , R 2 , R 3 , R 4 , R 5 and R 6(Formula II) is independently selected from H, linear, branched and cyclic alkyl, and aryl, and in Formula I, X is a divalent group of two or three atoms, the divalent group completing the ring structure. In a preferred aspect, in Formula I, R 1 , R 2 , R 3 and R 4 are independently selected from H, linear, branched and cyclic C1-C6 alkyl, and X is a divalent group of two or three atoms selected from the group consisting of C, N and O, wherein at least one atom is C. In a preferred aspect, in Formula II, R 1 , R 2 , R 3 , R 4 , R 5 and R 6 Independently selected from H, linear, branched and cyclic C1-C6 alkyl.

[0044] An exemplary nitrogen oxide-containing inhibitor of Formula II is di-tert-butylnitroxyl.

[0045] In preferred embodiments, exemplary nitrogen oxide-containing polymerization inhibitors include compounds of Formula III:

[0046]

[0047] Where R 1 , R 2 , R 3 and R 4 are independently selected from H, C1-C22 straight chain, branched chain, cyclic alkyl, and aryl, wherein X 1 ····X 2 and X 1 ····X 3 is CC or C=C, where X 4 is H or an unpaired electron, and where X 1 ····R 7 Selected from CO, C=O, CH, C-OR 8 and C-OC(O)R 8 , and where R 8 Selected from H, and C1-C22 straight chain, branched and cyclic alkyl, aryl, arylalkyl and alkylaryl.

[0048] Exemplary nitrogen oxide-containing polymerization inhibitors 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-butylnitroxyl, 1-oxy-2,2,6,6-tetramethyl-4-n-propoxypiperidinyl, 1-oxy-2,2,6,6-tetramethyl-4-n-but ...butoxypiperidinyl. -Tetramethyl-4-tert-butoxypiperidine, 1-oxy-2,2,6,6-tetramethyl-4-sec-butoxypiperidine, 1-oxy-2,2,6,6-tetramethyl-4-(2-methoxyethoxy)piperidine, 1-oxy-2,2,6,6-tetramethyl-4-(2-methoxyethoxyacetoxy)piperidine, 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl stearate, 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl acetate, 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl butyrate , 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl 2-ethylhexanoate, 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl octanoate, 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl laurate, 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl benzoate, 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl 4-tert-butylbenzoate, 1-oxy-2,2,6,6-tetramethyl-4-allyloxy-piperidin, 1-oxy-2,2,6,6-tetramethyl -4-acetylaminopiperidine, 1-oxy-2,2,6,6-tetramethyl-4-(N-butylformamido)piperidine, N-(1-oxy-2,2,6,6-tetramethylpiperidin-4-yl)-caprolactam, N-(1-oxy-2,2,6,6-tetramethylpiperidin-4-yl)-dodecylsuccinimide, 1-oxy-2,2,6,6-tetramethyl-4-(2,3-dihydroxypropoxy)piperidine, 1-oxy-2,2,6,6-tetramethyl-4-(2-hydroxy-4-oxapentyloxy)piperidine and mixtures thereof. (See, for example, U.S. Pat. No. 9,266,797.)

[0049] Other exemplary nitrogen oxide-containing polymerization inhibitors include two or three nitroxyl groups. Such compounds may be di- or tri-compounds derived from compounds of Formula I. For example, the ring structure containing the nitrogen oxide may be linked to the nitrogen oxide by a divalent linking group Q. 1 To provide a bis-nitrogen oxide compound according to formula IV or a trivalent linking group Q 2 To provide a tri-nitrogen oxide compound according to formula V, wherein R 1 '、R 2 '、R 3 ' and R4 ' and R 1" , R 2" , R 3" and R 4" respectively have the same R as described herein 1 , R 2 , R 3 and R 4 The same definition is given to X' and X" and X" have the same definition as X. 1 The divalent linking group may be formed from a compound selected from the group consisting of a diacid, a diester, a diamide, a diol, a diamine, and Q preferably having 1 to 22 carbons, 1 to 18 carbons, 1 to 15 carbons, 1 to 12 carbons, 1 to 9 carbons, or 1 to 6 carbons. 2 It may be a trivalent linking group formed from a compound selected from the group consisting of triacids, triols, amines and triazines preferably having 1 to 22 carbons, 1 to 18 carbons, 1 to 15 carbons, 1 to 12 carbons, 1 to 9 carbons or 1 to 6 carbons.

[0050]

[0051] Exemplary bis-nitrogen oxide and tris-nitrogen oxide polymerization inhibitor compounds include bis(1-oxy-2,2,6,6-tetramethylpiperidin-4-yl) succinate, bis(1-oxy-2,2,6,6-tetramethylpiperidin-4-yl) adipate, bis(1-oxy-2,2,6,6-tetramethylpiperidin-4-yl) sebacate, bis(1-oxy-2,2,6,6-tetramethylpiperidin-4-yl) n-butylmalonate, bis(1-oxy-2,2,6,6-tetramethylpiperidin-4-yl) phthalate, bis(1-oxy-2,2,6,6-tetramethylpiperidin-4-yl) isophthalate, bis(1-oxy-2,2,6,6-tetramethylpiperidin-4-yl) phthalate, 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, for example, U.S. Pat. No. 9,266,797.)

[0052] In some embodiments, a hydroxylamine polymerization inhibitor of Formula XIII is used:

[0053]

[0054] Among them, R 1 , R 2 , R 3 , R 4 , R 7 , X 1 , X 2 , X 3 has the same meaning as described in formula III.

[0055] The inhibitor compound may be a nitrogen oxide containing compound having a piperidinoneoxy group of Formula XIV:

[0056]

[0057] Where R 8selected from H, C1-C22 alkyl, C1-C22 aryl, C1-C22 arylalkyl and C1-C22 alkylaryl. Exemplary compounds of Formula XIV include 4-methoxy-2,2,6,6-tetramethylpiperidin-1-oxy, 4-ethoxy-2,2,6,6-tetramethylpiperidin-1-oxy, 4-propoxy-2,2,6,6-tetramethylpiperidin-1-oxy, 4-butoxy-2,2,6,6-tetramethylpiperidin-1-oxy, 4-pentyloxy-2,2,6,6-tetramethylpiperidin-1-oxy, 4-hexyloxy-2,2,6,6-tetramethylpiperidin-1-oxy, 4-heptyloxy-2,2,6,6-tetramethylpiperidin-1-oxy, methylpiperidin-1-oxyl, 4-octyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl, 4-nonyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl, 4-decyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl, 4-undecyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl, 4-dodecyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl, 4-tridecyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl, 4-tetradecyloxy- 2,2,6,6-tetramethylpiperidin-1-oxyl, 4-pentadecyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl, 4-hexadecyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl, 4-heptadecyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl, 4-octadecyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl, 4-nonadecyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl, 4-decyloxy-2,2,6,6-tetramethylpiperidin -1-oxy, 4-eicosyloxy-2,2,6,6-tetramethylpiperidin-1-oxy, 4-heneicosyloxy-2,2,6,6-tetramethylpiperidin-1-oxy, 4-docosyloxy-2,2,6,6-tetramethylpiperidin-1-oxy, 4-(phenoxy)-2,2,6,6-tetramethylpiperidin-1-oxy, 4-(benzyloxy)-2,2,6,6-tetramethylpiperidin-1-oxy, and 2,2,6,6-tetramethyl-4-(naphthalen-2-yloxy)piperidin-1-oxy.

[0058] Other nitrogen oxide-containing inhibitor compounds having a piperidinoneoxy group may be diradical compounds such as 4,4'-(ethane-1,2-diylbis(oxy))bis(2,2,6,6-tetramethylpiperidin-1-oxy), 4,4'-(propane-1,2-diylbis(oxy))bis(2,2,6,6-tetramethylpiperidin-1-oxy), 4,4'-(butane-1,4-diylbis(oxy)bis(2,2,6,6-tetramethylpiperidin-1-oxy), and may be triradical compounds such as 4,4',4"-(propane-1,2,3-triyltris(oxy)tris(2,2,6,6-tetramethylpiperidin-1-oxy). The inhibitor compound may be a nitrogen oxide-containing compound having a piperidinol group of Formula XV:

[0059]

[0060] Where R 8 is selected from the group consisting of H and C1-C22 alkyl, C1-C22 aryl, C1-C22 arylalkyl and C1-C22 alkylaryl. Exemplary compounds of Formula XV include

[0061] 2,2,6,6-tetramethylpiperidin-1,4-diol, 4-methoxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-ethoxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-propoxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-butoxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-pentyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-hexyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-heptyloxy-2 , 2,6,6-tetramethylpiperidin-1-ol, 4-octyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-nonyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-decyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-undecyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-dodecyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-tridecyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-tetradecyloxy 4-decyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-pentadecyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-hexadecyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-heptadecyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-octadecyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-nonadecyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-decyloxy-2,2,6,6-tetramethylpiperidin-1-ol piperidin-1-ol, 4-(phenoxy)-2,2,6,6-tetramethylpiperidin-1-ol, 4-(benzyloxy)-2,2,6,6-tetramethylpiperidin-1-ol and 2,2,6,6-tetramethyl-4-(naphthalen-2-yloxy)piperidin-1-ol.

[0062] Other nitrogen oxide-containing inhibitor compounds having a piperidinol group may be diradical compounds such as 4,4'-(ethane-1,2-diylbis(oxy))bis(2,2,6,6-tetramethylpiperidin-1-ol), 4,4'-(propane-1,2-diylbis(oxy)bis(2,2,6,6-tetramethylpiperidin-1-ol), 4,4'-(butane-1,4-diylbis(oxy))bis(2,2,6,6-tetramethylpiperidin-1-ol), and may be triradical compounds such as 4,4',4"-(propane-1,2,3-triyltri(oxy))tris(2,2,6,6-tetramethylpiperidin-1-ol).

[0063] The inhibitor compound may be a piperidinyloxy nitrogen oxide containing compound having the formula XVI:

[0064]

[0065] Where R 8 is selected from H and C1-C22 alkyl, C1-C22 aryl, C1-C22 arylalkyl and C1-C22 alkylaryl. Exemplary compounds of Formula XVI include 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl acetate, 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl propionate, 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl butyrate, 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl pentanoate, 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl hexanoate, 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl heptanoate, 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl octanoate, 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl nonanoate, 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl butylate, methylpiperidin-4-yl decanoate, 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl undecanoate, 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl dodecanoate, 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl 2-ethylhexanoate, 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl stearate, 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl benzoate, 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl palmitate, 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl behenate and 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl 4-tert-butylbenzoate.

[0066] Other nitrogen oxide-containing inhibitor compounds having a piperidinyloxy group may be diradical compounds such as bis(1-oxy-2,2,6,6-tetramethylpiperidin-4-yl)succinate, bis(1-oxy-2,2,6,6-tetramethylpiperidin-4-yl)adipate, bis(1-oxy-2,2,6,6-tetramethylpiperidin-4-yl)oxalate, bis(1-oxy-2,2,6,6-tetramethylpiperidin-4-yl)malonate, bis(1-oxy-2, bis(1-oxy-2,2,6,6-tetramethylpiperidin-4-yl) fumarate, bis(1-oxy-2,2,6,6-tetramethylpiperidin-4-yl) sebacate, bis(1-oxy-2,2,6,6-tetramethylpiperidin-4-yl) n-butylmalonate, bis(1-oxy-2,2,6,6-tetramethylpiperidin-4-yl) phthalate, bis(1-oxy-2,2,6,6-tetramethylpiperidin-4-yl) isophthalate, bis(1-oxy-2,2,6 ,6-tetramethylpiperidin-4-yl) terephthalate, bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) hexahydroterephthalate and N,N'-bis(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl) adipamide and 4,4'-ethylenebis(1-oxyl-2,2,6,6-tetramethylpiperazin-3-one), and may be trisyl compounds such as 2,4,6-tri-[N-butyl-N-(1-oxyl-2,

[0063] 2,6,6-tetramethylpiperidin-4-yl]-s-triazine and 4,4',4"-(propane-1,2,3-triyltri(oxy))tris(2,2,6,6-tetramethylpiperidin-1-ol). Other nitrogen oxide-containing inhibitor compounds having a piperidinyloxy group may be N-(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)-caprolactam and N-(1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl)-dodecylsuccinimide.

[0067] The inhibitor compound may be a nitrogen oxide containing compound having a piperidinol group of formula XVII:

[0068]

[0069] Where R 8selected from H and C1-C22 alkyl, aryl, arylalkyl and alkylaryl. Exemplary compounds of Formula XVII include 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl acetate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl propionate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl butyrate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl pentanoate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl hexanoate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl heptanoate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl octanoate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl nonanoate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl decanoate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl undecanoate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl dodecanoate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl 2-ethylhexanoate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl stearate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl benzoate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl palmitate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl behenate and 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl 4-tert-butylbenzoate.

[0070] Other nitrogen oxide-containing inhibitor compounds having a piperidinol group may be diradical compounds such as bis(1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl)succinate, bis(1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl)adipate, bis(1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl)sebacate, bis(1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl)n-butylmalonate, bis(1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl)phthalate, bis(1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl)isophthalate, bis(1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl)terephthalate, bis(1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl)iso ... 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl) hexahydroterephthalate, N,N'-bis(1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl) adipamide and 4,4'-ethylenebis(1-hydroxy-2,2,6,6-tetramethylpiperazin-3-one), and can be a tris-based compound such as 2,4,6-tri-[N-butyl-N-(1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl]-s-triazine, and other nitrogen oxide-containing inhibitor compounds having a piperidinol group can be N-(1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl)-caprolactam and N-(1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl)-dodecylsuccinimide.

[0071] 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.

[0072] Exemplary nitro-containing polymerization inhibitors include, but are not limited to, nitrobenzene, nitrophenol, dinitrophenol, 2,4-dinitro-6-tert-butylphenol, 2,4-dinitro-o-cresol, and diphenylpicrylhydrazyl.

[0073] Exemplary nitroso-containing polymerization inhibitors include, but are not limited to, nitrosobenzene, nitrosophenol, dinitrosophenol, dinitrosotoluene, and nitrosophenylhydroxylamine.

[0074] The compositions and methods of the present disclosure include or use polymerization retarders having quinone methide chemistry.

[0075] In some embodiments, the quinone methide blocker is a compound of Formula VI:

[0076]

[0077] Where R 1 and R 2 independently selected from C4-C18 alkyl, C5-C12 cycloalkyl, phenyl and C7-C15 cycloalkyl, wherein R 3 and R 4 independently selected from -H, C1-C18 alkyl, phenyl, substituted phenyl, C5-C12 cycloalkyl, -CN, -COOH, -C=CR 5 、-C≡CR 5 、-COOR 5 、-COR 5 、-OCOR 5 、-CONR 5 , where R 5 is selected from H, C1-C18 alkyl, C5-C12 cycloalkyl, phenyl and C7-C15 cycloalkyl and substituted phenyl. 1 and R 2 Independently selected from C4-C18 alkyl, preferably C4-C6 straight or branched chain alkyl, such as tert-butyl.

[0078] Exemplary quinone methide blockers include 2,6-di-tert-butyl-4-benzylidene-cyclohexa-2,5-dienone, 2,6-di-tert-butyl-4-(4-nitrobenzylidene)-cyclohexa-2,5-dienone, 2,6-di-tert-butyl-3-(4-nitrobenzylidene)-cyclohexa-2,5-dienone, 2,6-di-tert-butyl-4-(4-cyanobenzylidene)-cyclohexa-2,5-dienone, 2,6-di-tert-butyl-4-(4-methoxybenzylidene)-cyclohexyl-2,5-dienone, and 2,6-di-tert-butyl-4-(3,5-di-tert-butyl-4-hydroxybenzylidene)-cyclohexa-2,5-dienone. See, for example, U.S. Pat. No. 5,616,774 and U.S. Application Publication No. 2006 / 0163539.

[0079] The compositions and methods of the present disclosure include or use compounds having primary or secondary amine groups (referred to herein as "amine stabilizers") and different from polymerization inhibitors containing NO groups and quinone methide retarders. When used in combination with polymerization inhibitors containing NO groups and quinone methide retarders, the performance of the inhibitors and retarders can be improved. For example, the amine stabilizer can inhibit the polymerization of a monomer composition compared to the inhibitor alone, the retarder alone, or a mixture of the inhibitor and the retarder.

[0080] The amine stabilizer has one or more primary amine groups, one or more secondary amine groups, or a combination of primary and secondary amine groups. In embodiments, the amine stabilizer may exclude certain chemical properties, such as tertiary amine groups, ethylenically unsaturated groups, NO groups, or combinations thereof. Thus, in some embodiments, the amine stabilizer is composed of atoms of carbon (C), hydrogen (H), and nitrogen (N). Thus, in some embodiments, the amine stabilizer is composed of: (a) a hydrocarbyl group (a monovalent group derived from a hydrocarbon, such as methyl, ethyl, etc.), a hydrocarbylene group (a divalent group derived from a hydrocarbon, such as ethylene, propylene, etc.), or both a hydrocarbyl group and a hydrocarbylene group, and (b) one or more primary amine groups, one or more secondary amine groups, or both a primary amine group and a secondary amine group.

[0081] Amine stabilizers can also be described in terms of atomic composition, for example, an amine stabilizer has one or more primary and / or secondary amine groups, and at least 4 carbon atoms. In some preferred embodiments, the amine stabilizer has a carbon number in the range of 6 to 24, in the range of 7 to 24, or in the range of 8 to 24. The amine stabilizer may optionally contain one or more heteroatoms, such as oxygen or sulfur.

[0082] The carbon in the amine stabilizer can be described in terms of carbon-containing groups, and in some embodiments, the stabilizer includes at least one linear, branched, or cyclic alkyl group (i.e., a hydrocarbon group). In some cases, the amine stabilizer has a single alkyl group, and there are, for example, 4 or more (e.g., 6 to 24) total carbon atoms in the single alkyl group. In other cases, the amine stabilizer has more than one alkyl group, and the total carbon atoms, for example, 4 or more (e.g., 6 to 24), are divided into multiple alkyl groups. In some embodiments, the carbon-containing groups of the amine stabilizer do not include any: ethylenically unsaturated bonds (i.e., C=C bonds); do not include any tertiary amine groups; do not include any quaternary amine groups; or combinations thereof.

[0083] In some embodiments, the amine stabilizer can be a compound of Formula VII: R 1 NH2. In Formula VII, R 1 is a straight chain, branched or cyclic alkyl group of at least 4 carbon atoms, for example, a number of carbon atoms in the range of 4 to 24, 6 to 24 or 8 to 24. Exemplary compounds include:

[0084] 4-carbon primary amines, such as n-butylamine, sec-butylamine, tert-butylamine, isobutylamine,

[0085] 5-carbon primary amines, such as 2-methyl-2-butylamine, 2-methylbutylamine, 3-methylbutyl-2-amine, 3-methylbutylamine, n-pentylamine;

[0086] 6-carbon primary amines, such as n-hexylamine, 3,3-dimethyl-2-butylamine, isohexylamine, 3-(aminomethyl)pentane, 3,3-dimethylbutan-2-amine, 3,3-dimethylbutan-2-amine, 4-methylpentan-2-amine, 3,3-dimethylbutan-1-amine, 3-methylpentan-2-amine, hexan-2-amine, 4-methylpentan-1-amine, 2-methylpentan-1-amine, 3-methylpentan-2-amine, 2,3-dimethylbutan-1-amine, 2-methylpentan-2-amine, 3-methylpentan-3-amine, 2,3-dimethylbutan-2-amine, hexan-3-amine, aminocyclohexane, and the like;

[0087] 7-carbon primary amines, such as heptyl-1-amine, heptyl-2-amine, heptyl-3-amine, heptyl-4-amine, 5-methylhexan-2-amine, 4-methylhexan-2-amine, 3-ethylpentan-1-amine, 3-methylhexan-1-amine, 2,4-dimethylpentan-3-amine, 3-ethylpentan-3-amine, 2,4-dimethylpentan-2-amine, 2,3,3-trimethylbutan-2-amine, 3,4-dimethylpentan-2-amine, 5-methylhexan-1-amine, 4-methylhexan-3-amine, 3-methylhexan-2-amine, 3-ethylpentan-2-amine, 2,3-dimethylpentan-3-amine, 3-methylhexan-3-amine, 5-methylhexan-3-amine, 2,4-dimethylpentan-1-amine, 2,3,3-trimethylbutan- 1-amine, 2-methylhexan-1-amine, 3-(aminomethyl)hexane, 2-methylhexan-2-amine, 2,2-dimethylpentan-3-amine, 2-methylhexan-3-amine, 2,2-dimethylpentan-1-amine, 4-methylhexan-1-amine, 4,4-dimethylpentan-1-amine, 3,4-dimethylpentan-1-amine, 2,3-dimethylpentan-1-amine, 2,3-dimethylpentan-2-amine, 4,4-dimethylpentan-2-amine, 2,2,3-trimethylbutan-1-amine and 3,3-dimethylpentan-1-amine, cycloheptylamine, 2-methylcyclohexan-1-amine, 1-cyclohexylmethylamine, 1-methylcyclohexan-1-amine, 4-methylcyclohexan-1-amine, 3-methylcyclohexan-1-amine and the like;

[0088] 8-carbon primary amines, such as n-octylamine, octyl-2-amine, 6-methylheptyl-2-amine, 3-(aminomethyl)heptane, 4,4-trimethylpentyl-2-amine, octyl-2-amine, 6-methylheptyl-2-amine, 6-methylheptyl-1-amine, 2-methylheptyl-2-amine, 4-methylheptyl-3-amine, 3,5-dimethylhexan-1-amine, 3-ethyl-4-methylpentyl-1-amine, 4-ethylhexan-1-amine, 2,5-dimethylhexan-2-amine, 3,5-dimethylhexan-2-amine, 3-methylheptyl-2-amine, 3-ethylhexan-2-amine, 3,5-dimethylhexan-3-amine, 3-ethyl-2-methylpentyl-3-amine, 3-ethylhexyl-3-amine, 2,3,4-trimethylpentyl-3-amine, 2,3-dimethylhexan-3-amine, 2, 5-Dimethylhexan-3-amine, 2-methylheptan-4-amine, 2,2,4-trimethylpentan-3-amine, 4-(aminomethyl)heptane, 2,5-dimethylhexan-1-amine, 4-methylheptan-1-amine, 2-methylheptan-1-amine, 2,4-dimethylhexan-1-amine, 4-(aminomethyl)-2-methylhexane, 3-(aminomethyl)-2-methylhexane, octyl-4-amine, 2,2-dimethylhexan-3-amine, octyl-3-amine, 6-methylheptan-3-amine, 2-methylheptan-3-amine, 2,2-dimethylhexan-1-amine, 2,2-dimethylhexan-3-amine, 2,2,4-trimethylpentan-1-amine, 3-(aminomethyl)-3-methylhexane, 3-(aminomethyl)-3-ethylpentane, 4-ethylhexan-2 -amine, 5-methylheptyl-2-amine, 2,4-dimethylhexan-2-amine, 3-methylheptyl-3-amine, 4-methylheptyl-2-amine, 5,5-dimethylhexan-2-amine, 5,5-dimethylhexan-1-amine, 3,4-dimethylhexan-1-amine, 3-ethyl-4-methylpentan-2-amine, 3,4-dimethylhexan-3-amine, 6-methylheptyl-2-amine, 3-(aminomethyl)heptane, octyl-2-amine, 5-methylheptyl-3-amine, 2,4-dimethylhexan-3-amine, 3-methylheptyl-4-amine, 3,4,4-trimethylpentan-1-amine, 5-dimethylhexan-3-amine, 2,4,4-trimethylpentan-1-amine, 5-methylheptyl-1-amine, 4-methylheptyl-4-amine, 4,5-dimethylhexan-2-amine, 4,4 -dimethylhexan-2-amine, 4,5-dimethylhexan-3-amine, 3-(aminomethyl)-2,4-dimethylpentane, 3-ethyl-2-methylpentan-1-amine, 2,3,4-trimethylpentan-2-amine, 2,3,4-trimethylpentan-1-amine, 4,5-dimethylhexan-1-amine, 3-methylheptyl-1-amine, 3,3,4-trimethylpentan-1-amine, 2,3-dimethylhexan-1-amine, 3,4-dimethylhexan-2-amine, 3,4,4-trimethylpentan-2-amine, 3-(aminomethyl)-2,3-dimethylpentane, 3-ethyl-2-methylpentan-2-amine, 3-(aminomethyl)-4-methylhexane, 2,2,3-trimethylpentan-1-amine, 3,3-dimethylhexan-1-amine, 2,2,3,3-Tetramethylbutan-1-amine, 4-ethylhexan-3-amine, 3,3-dimethylhexan-2-amine, 3,3,4-trimethylpentan-2-amine, 3-(aminomethyl)-2,2-dimethylpentane, 5,5-dimethylhexan-3-amine, 3-methylheptan-4-amine, 2-methylheptan-4-amine, 2,2-dimethylhexan-3-amine, octane-4-amine, 4,4-dimethylhexan-3-amine, 2-methylheptan-4-amine, 6-methyl 3-Heptylamine, 4-octylamine, (2,2-dimethylcyclopentyl)methylamine, 2-ethylcyclohexyl-1-amine, 5-dimethylcyclohexyl-1-amine, cycloheptylmethylamine, 1-cyclohexylethyl-1-amine, 2-cyclopentylpropyl-1-amine, cyclooctylamine, 2,3-dimethylcyclohexyl-1-amine, 2-cyclohexylethyl-1-amine, 1-(methylcyclohexyl)methylamine, 4-ethylcyclohexyl-1-amine, 2,6-dimethylcyclohexyl-1-amine, etc.

[0089] In an embodiment, the stabilizer compound is selected from the group consisting of: 1- Hexylamine, wherein n1 is an integer in the range of 1 to 3 (i.e., 1-hexylamine, 2-hexylamine, or 3-hexylamine); n 2- Heptylamine or n 2- Octylamine, wherein n2 is an integer in the range of 1 to 4; n 3- Nonylamine or n 3- Decylamine, wherein n3 is an integer in the range of 1 to 5; or n 4- Undecylamine or n 4- Dodecylamine, wherein n4 is an integer in the range of 1 to 6.

[0090] In some embodiments, the amine stabilizer is a secondary amine compound of Formula VIII: R 2 NHR 3 , where R 2 and R 3 are independently selected from linear, branched or cyclic alkyl groups having 1 to 23 carbon atoms, provided that R 2 and R 3 The total number of carbon atoms in is at least 4, for example in the range of 4 to 24, 6 to 24, or 8 to 24 carbons. In some embodiments of Formula VII, R 2 and R 3 is independently selected from the group consisting of methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, cyclopentyl, methylcyclopentyl, hexyl, cyclohexyl, 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. In an embodiment, R2 and R 3 Together, they provide at least 6 carbon atoms, at least 7 carbon atoms, or at least 8 carbon atoms.

[0091] Exemplary compounds include 6-carbon secondary amines such as dipropylamine, ethyl(butyl)amine, (butyl-2-yl)(ethyl)amine, tert-butyl(ethyl)amine, methyl(pentyl)amine, (2-methylbutyl)(methyl)amine, (2-methylpropyl)(ethyl)amine, methyl(3-methylbutyl)amine, and the like.

[0092] Exemplary compounds include 7-carbon secondary amines such as ethyl(pentyl)amine, butyl(propyl)amine, (butyl-2-yl)(propyl)amine, tert-butyl(prop-2-yl)amine, hexyl(methyl)amine, (3,3-dimethylbut-2-yl)(methyl)amine, 3,3-dimethylbut-2-yl(methyl)amine, (2-ethylbutyl)(methyl)amine, methyl(4-methylpent-2-yl)amine, tert-butyl(propyl)amine, (2-methylpropyl)(prop-2-yl)amine, ethyl(3-methylbutyl)amine, butyl(prop-2-yl)amine, (2-methylprop- 1-Methylbutyl)amine, (2-methylpropyl)(ethyl)amine, (hex-2-yl)(methyl)amine, methyl(3-methylpentyl)amine, 2,3-dimethylpiperidine, 1,4-dimethylpiperidine, N-methylcyclohexylamine, and the like.

[0093] Exemplary compounds include 8-carbon secondary amines such as dibutylamine, (2-methylbutyl)(propyl)amine, ethyl(2-methylpentyl)amine, ethyl(3-methylpent-2-yl)amine, (2-methylbutyl)(propyl-2-yl)amine, (2-, 3-, 4- or 5-)ethyl(hexyl)amine, methyl(5-methylhex-3-yl)amine, (pent-3-yl)(propyl-2-yl)amine, bis(2-methylpropyl)amine, (hept-2-yl)(methyl)amine, tert-butyl(2-methylpropyl)amine , butyl(tert-butyl)amine, (hept-4-yl)(methyl)amine, (3-methylbutyl)(prop-2-yl)amine, (butyl-2-yl)(butyl)amine, heptyl(methyl)amine, bis(butyl-2-yl)amine, (3,4-dimethylpentan-2-yl)(methyl)amine, 2,4,6-trimethylpiperidine, 3-(2-methylpropyl)pyrrolidine, 3,3-diethylpyrrolidine, 2-tert-butylpyrrolidine, N-methylcycloheptylamine, N-ethylcyclohexylamine, N,3-dimethylcyclohexyl-1-amine.

[0094] Exemplary amine stabilizers also include cyclic secondary amines such as pyrrolidine and piperidine, and heterocyclic secondary amines such as morpholine.

[0095] Amine stabilizers of the present disclosure also include "polyamines", which refer to compounds having more than one primary amine group and / or secondary amine group. Polyamines include diamines, triamines, tetraamines, etc., wherein at least one amine group, some amine groups, or all amine groups in the polyamine are primary amines and / or secondary amines. Exemplary polyamines may have the formula X: N2(R 1 )N2, where R 1 is a linear, branched or cyclic divalent alkyl group, and the polyamine has at least 4 carbon atoms. Another exemplary polyamine has the formula XI: N2((R 2 )N(R 3 )) x , where R 2 is a linear, branched or cyclic (divalent) alkylene group, and R 3 is a linear, branched, or cyclic (monovalent) alkyl group, x is an integer, for example, in the range of 1 to 10, and the polyamine has at least 4 carbon atoms. Another exemplary polyamine has the formula XII: N2((R 2 )N(R 3 )) x N2, where R 2 is a linear, branched or cyclic (divalent) alkylene group, and R 3 is a linear, branched or cyclic (monovalent) alkyl group, x is an integer, for example in the range of 1 to 10, and the polyamine has at least 4 carbon atoms. The compounds of any one of Formulas X to XII may exclude certain chemical properties, such as tertiary amine groups, quaternary amine groups, ethylenically unsaturated groups, or combinations thereof.

[0096] In some embodiments, the amine stabilizer is a diamine. One exemplary class of diamines is an aryl diamine. An aryl diamine includes two amine groups, wherein at least one primary or secondary amine group is attached to the aryl group of the compound. Exemplary aryl diamine materials include o-phenylenediamine, m-phenylenediamine, and p-phenylenediamine. Phenylenediamines may also be substituted at one or more positions on the aryl group that are not bonded to the amine groups. Exemplary substituents include straight and branched alkyl groups.

[0097] The amine stabilizers of the present disclosure are generally in liquid or solid form at room temperature (25°C). Some amine stabilizers having about 12 carbon atoms or an alkyl chain length of 12 may be in solid form at room temperature. In some embodiments, the melting point of the amine stabilizer compounds of the present disclosure is in the range of about -50°C to about 100°C, in the range of about -30°C to about 80°C, or in the range of about -10°C to about 75°C. In some embodiments, the boiling point of the amine stabilizer compounds of the present disclosure is 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, 195°C or higher, for example, in the range of about 100°C to about 300°C or about 150°C to about 250°C.

[0098] The amount of polymerization inhibitor compounds, polymerization retarders and amine stabilizers in the composition can be described in various ways, such as by weight percentage (% wt.) of each component in the composition or by molar amount of the compound. These compounds can also be described by weight ratio or by the amount relative to each other in the composition.

[0099] In some embodiments, the total combined amount of the polymerization inhibitor and the polymerization compound (in % wt. or molar amount) is greater than the amount of the amine stabilizer in the composition. For example, the combined amount of the inhibitor compound and the retarder compound can be greater than about 1.5X, greater than about 2X, greater than about 2.5X, greater than about 3X, greater than about 3.5X, greater than about 4X, greater than about 4.5X, or greater than about 5X, greater than the amount of the polymerization inhibitor and the polymerization compound is greater than the amount (% wt. or molar amount) of the amine stabilizer compound in the composition. For example, the combined amount of the polymerization inhibitor and the polymerization retarder ranges from about 1.5X to about 50X, about 5X to about 25X, about 5X to about 25X, greater than the amount (% wt. or molar amount) of the amine stabilizer compound in the composition.

[0100] In some embodiments, the polymerization retarder (quinone methide) is present in an amount greater than the amine stabilizer in the composition. For example, the amount of the polymerization retarder is greater than about 1.2X, greater than about 1.5X, greater than about 2X, greater than about 2.5X, greater than about 3X, greater than about 3.5X, or greater than about 4. X is the amount of the amine stabilizer compound in the composition. For example, the polymerization retarder is greater than the amount of the amine stabilizer in the composition in a range of about 1.2X to about 25X, or about 2X to about 20X, or about 4X to about 15X.

[0101] In some embodiments, the polymerization inhibitor is present in an amount greater than the amine stabilizer in the composition. For example, the amount of the polymerization inhibitor is greater than about 1.1X, greater than about 1.3X, greater than about 1.6X, or greater than about 2X the amount of the amine stabilizer compound in the composition. For example, the amount of the polymerization inhibitor in the stabilizer compound in the composition is greater than about 1.1X to about 15X, or about 1.3X to about 10X, or about 1.6X to about 7X.

[0102] The polymerization inhibitor, polymerization retarder and amine stabilizer in the composition may be present in the composition with a solvent or solvent combination. The solvent or solvent combination may be selected so that one or more of the polymerization inhibitor, polymerization retarder and / or amine stabilizer is soluble in the solvent or solvent combination. If the amine stabilizer is a liquid under ambient conditions, the solvent may be selected so that it is miscible with the amine stabilizer.

[0103] Optionally, a composition or method comprising a polymerization inhibitor having NO functionality, a polymerization retarder that is a quinone methide, and a stabilizer that is a primary or secondary amine compound may further comprise an oxygen-containing amine compound, such as an oxygen-containing amine compound of the formula:

[0104]

[0105] Where R 1 , R 2 and R 3 independently selected from a) carbon and oxygen containing groups having 1 to 18 carbon atoms, b) carbon containing groups having 1 to 18 carbon atoms, and c) -OH, provided that R 1 , R 2 and R 3 At least one of which is a), wherein such compounds are disclosed in U.S. Provisional Application Serial No. 62 / 697,744 (Agent Docket No. ECO0173 / P1; N11255USP1) filed on July 13, 2018 and International Application Attorney Docket No. ECO0173 / WO (N11255WOU1), the disclosures of which are incorporated herein.

[0106] In embodiments, and taking into account the selection of inhibitors, retarders, and amine stabilizers, the amine stabilizer can also be used as a solvent and can be used to solvate the inhibitors and retarders. In these embodiments, the amine stabilizer can be used in an amount relative to the inhibitors and retarders as desired, or even in an amount greater than the inhibitors and retarders.

[0107] The composition may also include one or more solvents, and the one or more solvents may be different from the amine stabilizer. Useful solvents include any solvent in which the combination of inhibitors, retarders, and amine stabilizers can be dissolved or 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, paraffin solvents, or mixtures of the two.

[0108] Exemplary glycol solvents include, but are not limited to, 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 glycols, and the like, and combinations thereof. Commercial solvents such as butyl carbitol and butyl CELLOSOLVE can be used and obtained from DOW TM , which mainly contains butyl CARBITOL TM , BUTYL CARBITOL TM It is mainly composed of ethylene glycol monobutyl ether.

[0109] Exemplary hydrophobic solvents include heavy aromatic naphtha, toluene, ethylbenzene, and isomeric hexanes, and mixtures of two or more thereof.

[0110] In some embodiments the solvent is selected from glycols and aromatic naphthas and combinations thereof.

[0111] The amount of one or more solvents in the composition including the polymerization inhibitor, polymerization retarder and amine stabilizer is not particularly limited. In some embodiments, the amount of one or more solvents in the composition may be about 10 wt% to 50 wt%, about 20 wt% to 50 wt%, or about 25 wt% to 50 wt%, or about 10 wt% to 40 wt%, or about 10 wt% to 30 wt%, or about 20 wt% to 40 wt%, or about 25 wt% to 40 wt% of the total composition.

[0112] In some embodiments, the composition includes a polymerization inhibitor in an amount ranging from 5% to 50% (wt); preferably, a polymerization retarder in an amount ranging from 25% to 70% (wt); an amine stabilizer in an amount ranging from 0.5% to 15% (wt); and a solvent or a combination of solvents in an amount ranging from 10% to 50% (wt). In some embodiments, the composition includes a polymerization inhibitor in an amount ranging from 7.5% to 40% (wt); preferably, a polymerization retarder in an amount ranging from 30% to 60% (wt); an amine stabilizer in an amount ranging from 1% to 12% (wt); and a solvent or a combination of solvents in an amount ranging from 15% to 45% (wt). In some embodiments, the composition includes a polymerization inhibitor in an amount ranging from 10% to 30% (wt); preferably, a polymerization retarder in an amount ranging from 35% to 55% (wt); an amine stabilizer in an amount ranging from 3% to 9% (wt); and a solvent or a combination of solvents in an amount ranging from 20% to 40% (wt).

[0113] Any desired method may be used to make the compositions of the present disclosure. However, in some embodiments, it may be beneficial to add the amine stabilizer to the polymerization inhibitor before adding the polymerization retarder, or vice versa.

[0114] Thus, the present disclosure provides a method for preparing a composition for inhibiting monomer polymerization, wherein a first composition is obtained comprising (i) a polymerization inhibitor (e.g., a nitroxide polymerization inhibitor) and (ii) an amine stabilizer, and optionally a solvent or a combination of solvents, and then (iii) a retarder compound which is a quinone methide is added to the first composition.

[0115] In another method, a first composition is obtained comprising (i) a retarder compound which is a quinone methide and (ii) an amine stabilizer, and optionally a solvent or combination of solvents, and then (iii) a polymerization inhibitor (e.g., a nitroxide polymerization inhibitor) is added to the first composition.

[0116] Yet another method of the present disclosure involves combining simultaneously or sequentially (i) a retarder compound that is a quinone methide, (ii) a polymerization inhibitor (eg, a nitroxide polymerization inhibitor), and (iii) an amine stabilizer to form a composition for inhibiting polymerization of a monomer.

[0117] For example, a formulation of the amine stabilizer with a polymerization inhibitor or polymerization retarder and optionally with a solvent may be obtained by the user, such as a commercial formulation, and then the polymerization retarder or polymerization inhibitor may be added subsequently, such as at a point in the user's procedure.

[0118] A composition comprising a mixture of a polymerization inhibitor, a polymerization retarder and an amine stabilizer, optionally with a solvent, can be provided as a "shelf-stable" composition, which is then used in a process for inhibiting monomer polymerization. Since the amine-based stabilizers of the present invention can hinder the antagonistic effects that may occur when inhibitors and retarders are used in combination, the mixture can be prepared and stored for a longer period of time (e.g., weeks, months, etc.) without greatly reducing the anti-polymerization activity. For example, the method of the present disclosure can include the steps of preparing a composition of a polymerization inhibitor, a polymerization inhibition retarder, an amine stabilizer and a solvent, then storing the composition for a period of time, such as 700 days to 36 months, and then using the composition in a process for inhibiting monomer polymerization.

[0119] A method of mitigating polymerization of monomers in a composition containing monomers can be performed by adding a composition comprising a polymerization inhibitor, a polymerization retarder, and an amine stabilizer. The inhibitor and the retarder inhibit polymerization of the polymerizable monomers, and the presence of the amine stabilizer improves the anti-polymerization properties of the inhibitor and the retarder.

[0120] The polymerizable monomers that are inhibited from polymerization may include vinyl or ethylenically unsaturated groups. For example, components of inhibitors, retarders, and amine stabilizers may be added to a composition comprising one or more of the following polymerizable monomers: acrylic acid, acrylonitrile, alkylated styrenes, butadiene, chloroprene, divinylbenzene, ethyl acrylate, ethyl methacrylate, isoprene, methacrylic acid, methyl methacrylate, methyl acrylate, alpha-methylstyrene, methacrylonitrile, styrene, styrene sulfonic acid, vinyltoluene, and vinylpyridine.

[0121] The polymerizable monomers may be present in a crude mixture of compounds, a semi-refined mixture of compounds, or a fully refined mixture of compounds. For example, components of inhibitors, retarders, and amine stabilizers may be added to a process stream comprising polymerizable monomers. In the method, the components may 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 one another. The components may inhibit polymerization of the monomers at any one or more stages in the processing system and minimize fouling of the equipment.

[0122] Alternatively, the composition of inhibitors, retarders, and amine stabilizers can be added to a process stream that includes a compound capable of polymerizing a monomer. For example, in a composition that includes a compound capable of forming a polymerizable monomer as an undesirable byproduct, if a polymerizable monomer does form as a byproduct, the presence of the inhibitors, retarders, and amine stabilizers will inhibit polymerization of the monomer and, therefore, can minimize fouling of the equipment.

[0123] In some practice modes, inhibitors, retarder and amine stabilizer are introduced into the composition containing monomers to provide the required amount of each agent in the composition. Inhibitors, retarder and amine stabilizer can be introduced simultaneously, for example, delivered from the composition of component mixing, or can be delivered individually or partially in combination sequentially or in an overlapping manner. The components are finally introduced into the composition containing monomers to provide the desired concentration of inhibitors, retarder and amine stabilizer. For example, in the range of 50ppm to 200ppm of polymerizable monomer concentration, inhibitors can be introduced to provide an amount in the range of 15ppm to 60ppm, retarder can be introduced to provide an amount in the range of 25ppm to 100ppm, and stabilizer compounds can be introduced to provide an amount in the range of 1ppm to 15ppm. As another example, in the range of 100ppm to 150ppm of polymerizable monomer concentration, inhibitors can be introduced to provide an amount in the range of 25ppm to 50ppm, retarder can be introduced to provide an amount in the range of 40ppm to 80ppm, and stabilizer compounds can be introduced to provide an amount in the range of 2ppm to 12ppm.

[0124] The term "fouling" refers to the formation of polymers, prepolymers, oligomers and / or other materials that are insoluble in a stream and / or precipitate from a stream and deposit on equipment under equipment operating conditions. Consequently, the inhibitor, retarder and amine stabilizer components and compositions of the present disclosure may be referred to as "antifoulants" because they inhibit or reduce such formation.

[0125] Optionally, the ability of the compositions of the present disclosure to inhibit polymerization can be described relative to a composition that does not include an amine stabilizer. The effect of the amine stabilizer can be understood by measuring the formation of polymer (e.g., polystyrene) in a monomer (e.g., styrene) composition over time in the presence of an inhibitor / retarder / amine stabilizer composition relative to an inhibitor / retarder composition (comparative). For example, the ability of the compositions of the present disclosure with an inhibitor, a retarder, and an amine stabilizer to inhibit polymerization of a monomer is more than two times, more than five times, or more than ten times greater than a composition of the compound with an inhibitor and a retarder but no stabilizer compound under the same conditions.

[0126] The components of inhibitors, retarders, and amine stabilizers may be used in conjunction with a composition containing polymerizable monomers and "process equipment" (e.g., reactors, reactor beds, piping, valves, distillation columns, trays, condensers, heat exchangers, compressors, fans, impellers, pumps, recirculators, intercoolers, sensors, etc.) that are associated with the process and that may be fouled by polymerization of the monomers. This term also includes collections of these components where more than one of the components is part of a "system."

[0127] In a preferred method of use, the disclosed compositions having inhibitors, retarders, amine stabilizers and solvents (e.g., diols) are used together with processes involving distillation towers for separating and purifying vinyl monomers. For example, ethylbenzene can be subjected to catalytic dehydrogenation reactions in processes known in the art, resulting in the formation of styrene. The reaction product containing styrene also contains other compounds, such as aromatic compounds (e.g., toluene and benzene), unreacted ethylbenzene and other materials (e.g., polymers). This mixture of compounds is typically fractionated using one or more distillation towers. Typically, heat is used to help separate the components in the distillation tower. After distillation, the fractionated components can be separated into pure product streams with higher purity.

[0128] The inhibitor / retardant / amine stabilizer / solvent composition can be introduced into the feed stream from the reaction bed to the distillation column, or can be 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 an embodiment, the boiling point of the amine stabilizer is greater than the desired compound (e.g., a monomer such as styrene) subjected to the distillation column, and during the distillation process, the desired compound is separated from the amine stabilizer due to the temperature difference. In an embodiment, the boiling point difference between the compound of interest and the amine stabilizer is about 10°C or higher, about 15°C or higher, about 20°C or higher, about 25°C or higher, about 30°C or higher, about 35°C or higher, about 40°C or higher, about 45°C or greater, or about 50°C or higher.

[0129] 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.

[0130] The components of inhibitors, retarders and amine stabilizers can be used in conjunction with "petroleum products", which refers to any hydrocarbon product obtained from an underground reservoir, any product derived therefrom, or any mixture thereof. Polymerizable monomers are present in petroleum products or can be chemically derived from petroleum products. Non-limiting examples of petroleum products include, but are not limited to, crude oil, crude oil after distillation, crude oil fractions, heavy oil or asphalt, hydrogenated oil, refined oil, by-products of petroleum product processing (such as pyrolysis, hydroprocessing or phase separation), or a mixture of two or more of these. Liquid petroleum products are petroleum products that are substantially liquid at 20°C.

[0131] Components of inhibitors, retarders and amine stabilizers may be added to or may be present in a "petroleum process stream," which refers to any petroleum product placed within petroleum process equipment and in fluid contact with its inner surface. A petroleum process stream may include one or more polymerizable monomers, or may be capable of forming one or more polymerizable monomers as a byproduct. A process stream may be substantially static, such as a petroleum product placed in a settler (separator) or storage container for a selected contact time, such as up to two years. A process stream may be substantially dynamic, such as a liquid petroleum product placed in a pipe during transportation of the product from a first location to a second location. In some embodiments, the process stream includes one or more other components related to petroleum processing; these components are not particularly limited.

[0132] As used herein, the terms "petroleum process equipment," "petroleum process unit," and similar terms mean a man-made article having an interior surface comprising metal, further wherein one or more petroleum products are in contact with a metallic fluid for any period of time at any temperature as further determined by the context. Petroleum process equipment includes articles used to remove petroleum products from underground reservoirs, to transport one or more petroleum products from a first location to a second location, or to separate, refine, treat, separate, distill, react, meter, heat, cool, or contain one or more petroleum products.

[0133] In embodiments, the composition comprising inhibitors, retarders, and amine stabilizers is thermally stable and has polymerization inhibitor and retarder activity, and the composition has properties in a process stream or other composition containing polymerizable monomers at a temperature of about 20°C to about 400°C, for example, about 100°C to 400°C, or about 100°C to 350°C, or about 100°C to 300°C, or about 100°C to 250°C, or about 100°C to 200°C, or about 100°C to 150°C.

[0134] In embodiments, a composition comprising inhibitors, retarders, and amine stabilizers may be introduced into a composition having polymerizable monomers, such as a liquid petroleum process stream, in a batch, continuous, or semi-continuous manner. In some embodiments, the inhibitors, retarders, and amine stabilizers are introduced manually; in other embodiments, their introduction is automated. In embodiments, the amount of inhibitors, retarders, and amine stabilizers introduced within a selected unit of time varies with the variable composition of the associated petroleum process stream. Such dosage variability may be performed manually: by periodic testing of the internal surfaces of liquid petroleum process equipment, and then adjusting the amount of the composition up or down based on the test results; or by automatically monitoring one or more conditions inside the petroleum process equipment and signaling the need to apply more of the composition to the process stream.

[0135] In some embodiments, the inhibitors, retardants and amine stabilizers are added to a petroleum product that is a crude oil, reduced crude oil, heavy oil, asphalt, coker feed, hydrotreater feed, hydrotreater effluent, flash, light cycle oil or diesel or naphtha refinery stream. In embodiments, the compounds are added to petroleum process equipment that is typically associated with the collection, processing, transportation or storage of one or more of crude oil, distilled crude oil, crude oil fractions, heavy oil, asphalt, coker charge, flash crude, light cycle oil or diesel or naphtha refinery streams, including pipelines and related infrastructure for fluidly connecting process equipment items together to facilitate processing of process streams placed therein.

[0136] Equipment containing compositions containing polymerizable monomers treated with inhibitors, retarders, and amine stabilizers can reduce or eliminate scaling on the internal surfaces of the equipment. In embodiments, scaling is measured as a relative increase in solid retention in the treated composition compared to solid retention in an untreated composition over the same time period. In embodiments, scaling is measured as a relative decrease in the weight or volume of precipitate produced by a treated process stream in an associated process equipment item over a selected contact time relative to process equipment with a corresponding untreated process stream over the same contact time. In other words, the reduction in scaling is a relative reduction in the weight or volume of solids deposited or precipitated from an untreated process stream over a selected time period when compared to the weight or volume of solids deposited or precipitated from the untreated process stream over the same time period.

[0137] Inhibitors, retarders and amine stabilizers can also inhibit unwanted polymerization and fouling of process equipment during primary fractionation processes, light ends fractionation, non-aromatic halide vinyl fractionation, process gas compression, dilution steam systems, caustic treatment towers, quench water towers, butadiene extraction, propane dehydrogenation, diesel and gasoline fuel stabilization, olefin metathesis, styrene purification, hydroxy hydrocarbon purification, or retard the polymerization of resins and compositions containing ethylenically unsaturated species.

[0138] Inhibitors, retarders and amine stabilizers can be added at any given point and one or more locations in the process. For example, the anti-fouling composition can be added directly at the intercooler or compressor or upstream of the intercooler or compressor. In order to inhibit or reduce fouling, inhibitors, retarders and amine stabilizers can be added to the process equipment continuously or intermittently as needed.

[0139] The inhibitors, retarders, and amine stabilizers may be introduced into the desired system by any suitable method. For example, they may be added neat or in the form of a diluted solution. In some embodiments, the composition containing the inhibitors, retarders, and amine stabilizers may be applied as a solution, emulsion, or dispersion that is sprayed, dripped, poured, or injected into a desired opening within the system or onto process equipment or process condensate. In some embodiments, the composition may be added with wash oil or tempered water.

[0140] After the composition is introduced into the process equipment, it can be observed that the treated process equipment has less deposits on the equipment compared to the process equipment without the addition of the composition. The reduction or inhibition of fouling can be evaluated by any known method or test. In some embodiments, the reduction or inhibition of fouling can be obtained by measuring the time required for samples with and without the antifouling agent composition to gel. See the Experimental section for more details.

[0141] The following illustrative, non-limiting examples are provided.Examples 1 to 5, 7 to 10, and 12 to 14 detail the preparation of experimental composition components or show formulations for comparative purposes.

[0142] Example 1

[0143] HTEMPO in Styrene

[0144] 2.0 g of 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (HTEMPO) was dissolved in de-inhibited styrene to give 0.33 mmolar in 350 g of solution. 4-tert-butylcatechol (TBC) stabilizer was removed from styrene just before the treatment composition was added. Alumina columns were used to remove the stabilizer. 10 mL of solution was loaded into each of twenty-four Ace Glass #15 threaded pressure tubes equipped with PTFE screw caps and fluoroelastomer (FETFE) O-rings. For each test tube, dissolved oxygen in the solution was purged out by bubbling with nitrogen for 2 minutes. After bubbling, each tube was immediately sealed and the solution was kept under nitrogen headspace. The tubes were loaded into a heating block preheated to 120°C. After 30 minutes and every 15 minutes thereafter, four tubes were removed from the block and the polymerization reaction was quenched by cooling in an ice bath. The cooled polymer solution was immediately diluted with toluene. Special methods were also used to measure the polymer. See Tables 1 and 2 and Figure 1 and Figure 2 .

[0145] Example 2

[0146] 7-Phenylquinone Methide (7-PhQM) in Styrene

[0147] For further comparison purposes, a solution of 100 ppm (0.33 mmolar) of 7-PhQM in 350 g of inhibitor-free styrene was prepared and then tested for anti-polymerization properties according to the procedure of Example 1. See Tables 1 and 2 and Figure 1 and Figure 2 .

[0148] Example 3

[0149] Co-doping HTEMPO and 7-phenylquinone methide in styrene

[0150] For further comparison purposes, a solution of 68.7 ppm (0.33 mmolar) of 7-PhQM and 31.3 ppm of HTEMPO was prepared and added to 350 g of inhibitor-free styrene just before testing (co-injection). Immediately thereafter, the anti-polymerization properties were tested according to the procedure in Example 1. See Tables 1 and Figure 1 .

[0151] Example 4

[0152] Untreated styrene

[0153] Immediately after removing TBC from styrene, a 10 mL sample of the styrene was loaded into each of the aforementioned pressure tubes. After purging the dissolved oxygen from the solution, polymerization and polymer analysis were performed according to the procedures in Example 1. See Tables 1 and 2 and Figure 1 and Figure 2 .

[0154] Example 5

[0155] HTEMPO, 7-PhQM and Butyl Carbitol in Styrene

[0156] A composition consisting of 4.4 g of 7-phenylquinone methide (7-PhQM), 3.6 g of ethylbenzene, 2.0 g of 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (HTEMPO) and 2-(butoxymethoxy)ethane-1-ol (butyl carbitol) was prepared. After one week of incubation (premixing), it was screened to determine its anti-polymerization properties. Immediately thereafter, the anti-polymerization properties were tested according to the procedure in Example 1. See Tables 2 and Figure 2 .

[0157] Example 6

[0158] HTEMPO, 7-PhQM, Butyl Carbitol and 1-Octylamine in Styrene A composition consisting of 4.4 g of 7-phenylquinone methide (7-PhQM), 3.0 g of ethylbenzene, 2.0 g of 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (HTEMPO) and 2-(butoxymethoxy)ethane (butyl carbitol) was prepared as in Example 1. In order to stabilize the composition, 0.6 g of 1-octylamine was added. The incubation product was screened for anti-polymerization activity using the procedure in Example 1. The presence of 1-octylamine resulted in a mixture of HTEMPO and 7-PhQM having improved anti-polymerization properties, as evidenced by a reduction in the amount of polystyrene formed relative to the control at all measured time points, especially at the later measured time points (+75 minutes). See Tables 2 and Figure 2 .

[0159] Table 1: Performance of anti-polymerizers when co-injected into styrene, expressed as a percentage of polymer (by weight).

[0160]

[0161] Table 2: Polymer percentage (weight to weight) showing properties of amine stabilized and amine-free one-pack anti-polymer compositions.

[0162]

[0163] Example 7

[0164] 4-ACETIC ACID TEMPOH in Styrene

[0165] 200 ppm of 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl acetate (4-acetic acid TEMPOH) was added to freshly prepared styrene (without stabilizer) and then a kinetic study was performed to determine the anti-polymerization properties according to the procedure in Example 1. Table 3 shows the results of the % (w / w) of polystyrene over time.

[0166] Example 8

[0167] 7-CO2HQM in Styrene

[0168] A 200 ppm solution of 7-carboxylic acid quinone methide / 2-(3,5-di-tert-butyl-4-oxocyclohexa-2,5-dienyl-1-ylidene)acetic acid (7-CO2HQM) was prepared using freshly prepared styrene. Anti-polymerization properties were determined according to the procedure in Example 1. Table 3 shows the accumulation of polystyrene (% w / w) with respect to time.

[0169] Table 3

[0170] Time (minutes) 200ppm 4-Acetic acid TEMPOH <![CDATA[200ppm CO2HQM]]> 30 0.0169 0.0763 45 0.0251 0.441 60 0.0365 1.50 75 0.0550 3.60 90 0.0632 6.38 105 0.109 7.40 120 1.70 10.0

[0171] Example 9

[0172] QMPh in Styrene

[0173] As shown in the previous examples, freshly prepared styrene was treated with 32 ppm of QMPh. The anti-polymerization properties demonstrated in Example 1 were determined. Table 4 shows the resulting polystyrene concentration (% w / w) versus time.

[0174] Example 10

[0175] QMPh and 4-acetic acid TEMPO in styrene

[0176] A styrene solution of 22 ppm QMPh and 10 ppm TEMPO 4-acetate was prepared. Using the procedure in Example 1, the anti-polymerization properties were determined; see Table 4 for the results.

[0177] Example 11

[0178] QMPh, 4-acetic acid TEMPO and 2-ethylhexylamine in styrene

[0179] A styrene solution of 22 ppm QMPh and 10 ppm TEMPO-4-acetate was prepared, stabilized by 6 ppm 2-ethylhexylamine. The properties of this combination were determined according to the procedure in Example 1; the results are shown in Table 4. The presence of 2-ethylhexylamine resulted in a mixture of TEMPO-4-acetate and QMPh having improved resistance to polymerization, as evidenced by a reduction in the amount of polystyrene formed at all time points measured relative to the control.

[0180] Table 4.

[0181]

[0182] Example 12

[0183] QMPh in Styrene

[0184] A 2.57 mmolal QMPh solution was prepared using freshly purified styrene. The anti-polymerization properties were determined using the procedure in Example 1. See Table 5 for the results.

[0185] Example 13

[0186] QMPh and TIPA in Styrene

[0187] For comparison, a 2.31 mmolal QMPh solution (which is 90% (mol / mol) of the QMPh concentration in Example 12) and 0.257 mmolal triisopropanolamine (TIPA) (10% mol / mol of the QMPh concentration in Example 12) were prepared using freshly purified styrene. The performance of the combination was determined using the procedure in Example 1. See Table 5 for the results.

[0188] Example 14

[0189] QMPh and 4-acetic acid TEMPOH in styrene

[0190] As in Example 13, a solution of 2.31 mmolal QMPh and 0.257 mmolal 4-acetic acid TEMPOH was prepared using freshly purified styrene. The performance of this illustrative combination was determined according to the procedure in Example 1. Table 5 shows the effect on the performance of this combination.

[0191] Example 15

[0192] QMPh, HTEMPOH and Dipropylamine in Styrene

[0193] Another illustrative example was performed by preparing a styrene solution combining 2.31 mmolal QMPh, 0.173 mmolal 2,2,6,6-tetramethylpiperidine-1,4-diol (HTEMPOH) and 0.0719 mmolal (71.9 μmolal) dipropylamine. The performance of this illustrative combination was determined using the procedure in Example 1. The effect of the amine on the performance of this combination is shown in Table 5. The presence of dipropylamine results in a mixture of HTEMPOH and QMPh having improved resistance to polymerization, as evidenced by a reduction in the amount of polystyrene formed at all time points measured relative to the control.

[0194] Table 5: Examples of synergistic combinations of 4-acetic acid TEMPO and QMPh and amines.

[0195]

Claims

1. A composition for inhibiting monomer polymerization, comprising: An inhibitor compound having a structure according to Formula III: Where R 1 , R 2 , R 3 and R 4 are independently selected from H, C1-C22 straight chain, branched chain, cyclic alkyl, and aryl, wherein X 2 ····X 1 and X 1 ····X 3 is CC or C=C, where X 4 is H or an unpaired electron, and where X 1 ····R 7 Selected from CO, C=O, CH, C-OR 8 and C-OC(O)R 8 , and where R 8 is selected from H, and C1-C22 straight chain, branched and cyclic alkyl, C6-C22 aryl, arylalkyl and alkylaryl; The retarder compound is a quinone methide having a structure according to Formula VI: Where R 9 and R 10 independently selected from C4-C18 alkyl, C5-C12 cycloalkyl, phenyl and C7-C15 cycloalkyl, wherein R 11 and R 12 independently selected from -H, C1-C18 alkyl, phenyl, substituted phenyl, C5-C12 cycloalkyl, -CN, -COOH, -C=CR 13 、-C≡CR 13 、-COOR 13 、-COR 13 、-OCOR 13 、-CONR 13 , where R 13 is selected from H, C1-C18 alkyl, C5-C12 cycloalkyl, phenyl and C7-C15 cycloalkyl and substituted phenyl; and A stabilizer compound comprising a primary amine having the formula R 14 NH2, where R 14 It is a straight or branched chain alkyl group having 4 to 24 carbon atoms.

2. The composition according to claim 1, wherein R 14 It is a straight or branched chain alkyl group having 8 carbon atoms.

3. The composition according to claim 1, wherein R 14 It is n-octyl or ethylhexyl.

4. The composition of any one of claims 1-3, wherein the inhibitor compound is capable of generating a stable free radical on an oxygen atom.

5. The composition of any one of claims 1-3, wherein the inhibitor compound comprises a piperidinyloxy or piperidinol group.

6. The composition of claim 5, wherein the inhibitor compound has a structure according to Formula IIIa: Where R 8 is selected from H, and C1-C22 alkyl, aryl, arylalkyl and alkylaryl.

7. The composition of claim 6, wherein the inhibitor compound is selected from the group consisting of 1-oxy-2,2,6,6-tetramethylpiperidin-4-ol, 4-methoxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-ethoxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-propoxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-butoxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-pentoxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-hexoxy-2,2,6,6-tetramethylpiperidin-1-ol, -2,2,6,6-tetramethylpiperidin-1-oxyl, 4-heptyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl, 4-octyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl, 4-nonyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl, 4-decyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl, 4-undecyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl, 4-dodecyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl, 4-tridecyloxy-2,2, 6,6-tetramethylpiperidin-1-oxyl, 4-tetradecyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl, 4-pentadecyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl, 4-hexadecyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl, 4-heptadecyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl, 4-octadecyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl, 4-nonadecyloxy-2,2,6,6-tetramethylpiperidin-1-oxyl, 4-decyloxy- 2,2,6,6-tetramethylpiperidin-1-oxy, 4-eicosyloxy-2,2,6,6-tetramethylpiperidin-1-oxy, 4-heneicosyloxy-2,2,6,6-tetramethylpiperidin-1-oxy, 4-docosyloxy-2,2,6,6-tetramethylpiperidin-1-oxy, 4-(phenoxy)-2,2,6,6-tetramethylpiperidin-1-oxy, 4-(benzyloxy)-2,2,6,6-tetramethylpiperidin-1-oxy and 2,2,6,6-tetramethyl-4-(naphthalen-2-yloxy)piperidin-1-oxy.

8. The composition of claim 5, wherein the inhibitor compound has a structure according to Formula IIIb: Where R 8 is selected from H, and C1-C22 alkyl, aryl, arylalkyl and alkylaryl.

9. The composition of claim 8, wherein the inhibitor compound is selected from the group consisting of: 2,2,6,6-tetramethylpiperidin-1,4-diol, 4-methoxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-ethoxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-propoxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-butoxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-pentyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-hexyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-heptyloxy- 2,2,6,6-tetramethylpiperidin-1-ol, 4-octyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-nonyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-decyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-undecyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-dodecyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-tridecyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-tetradecyloxy 4-decyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-pentadecyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-hexadecyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-heptadecyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-octadecyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-nonadecyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-decyloxy-2,2,6,6-tetramethylpiperidin-1-ol tetramethylpiperidin-1-ol, 4-eicosyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-heneicosyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-docosyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-(phenoxy)-2,2,6,6-tetramethylpiperidin-1-ol, 4-(benzyloxy)-2,2,6,6-tetramethylpiperidin-1-ol and 2,2,6,6-tetramethyl-4-(naphthalen-2-yloxy)piperidin-1-ol.

10. The composition of claim 5, wherein the inhibitor compound has a structure according to Formula IIIc: Where R 8 is selected from H, and C1-C22 alkyl, aryl, arylalkyl and alkylaryl.

11. The composition of claim 10, wherein the inhibitor compound is selected from the group consisting of: 1-Oxy-2,2,6,6-tetramethylpiperidin-4-yl acetate, 1-Oxy-2,2,6,6-tetramethylpiperidin-4-yl propionate, 1-Oxy-2,2,6,6-tetramethylpiperidin-4-yl butyrate, 1-Oxy-2,2,6,6-tetramethylpiperidin-4-yl pentanoate, 1-Oxy-2,2,6,6-tetramethylpiperidin-4-yl hexanoate, 1-Oxy-2,2,6,6-tetramethylpiperidin-4-yl heptanoate, 1-Oxy-2,2,6,6-tetramethylpiperidin-4-yl octanoate, 1-Oxy-2,2,6,6-tetramethylpiperidin-4-yl nonanoate, 1-Oxy-2,2,6,6-tetramethylpiperidin 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl 2-ethylhexanoate, 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl stearate, 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl benzoate, 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl palmitate, 1-oxy-2,2,6,6-4-yl behenate and 1-oxy-2,2,6,6-tetramethylpiperidin-4-yl 4-tert-butylbenzoate.

12. The composition of claim 5, wherein the inhibitor compound has a structure according to Formula IIId: Where R 8 is selected from H, and C1-C22 alkyl, aryl, arylalkyl and alkylaryl.

13. The composition of claim 12, wherein the inhibitor compound is selected from the group consisting of 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl acetate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl propionate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl butyrate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl pentanoate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl hexanoate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl heptanoate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl octanoate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl nonanoate, 1-hydroxy- 2,2,6,6-tetramethylpiperidin-4-yl decanoate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl undecanoate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl dodecanoate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl 2-ethylhexanoate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl stearate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl benzoate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl palmitate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl behenate, 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl 4-tert-butylbenzoate.

14. The composition of claim 1, wherein the inhibitor is 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) and 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-one or a combination thereof.

15. The composition of any one of claims 1-3, wherein the quinone methide retarder is 7-phenylquinone methide.

16. The composition of any one of claims 1-3, wherein the total amount of the inhibitor compound, the retarder compound, or both the inhibitor compound and the retarder compound is present in a molar amount greater than the stabilizer compound.

17. The composition of any one of claims 1-3, wherein the molar amount of the inhibitor compound or the retarder compound is more than 1.5 times that of the stabilizer compound.

18. The composition of any one of claims 1-3, wherein the molar amount of the inhibitor compound or the retarder compound is more than 2 times that of the stabilizer compound.

19. The composition according to any one of claims 1 to 3, further comprising an organic solvent.

20. The composition according to claim 19, wherein The amount of the inhibitor compound is in the range of 5% to 50% (wt); The amount of the retarder compound is in the range of 25% to 70% (wt); The amount of the stabilizer compound is in the range of 0.5% to 15% (wt); and The amount of the organic solvent is in the range of 15% to 50% (wt).

21. The composition according to claim 20, wherein The amount of the inhibitor compound is in the range of 10% to 30% (wt); The amount of the retarder compound is in the range of 35% to 55% (wt); The amount of the stabilizer compound is in the range of 3% to 9% (wt); and The amount of the organic solvent is in the range of 20% to 40% (wt).

22. Use of a composition according to any one of claims 1 to 21 for inhibiting the polymerisation of monomers in a composition.

23. Use of the composition according to any one of claims 1 to 21 in a process for synthesizing, refining or purifying a polymerizable monomer.

24. Use of the composition according to any one of claims 1 to 21 in the storage or transportation of polymerizable monomers.

25. A method for preparing a composition according to any one of claims 1 to 21, the method comprising: combining in sequence (i) an inhibitor compound, (ii) a stabilizer compound, and (iii) a blocker compound; Combining in sequence (i) a blocker compound (ii) a stabilizer compound and (iii) an inhibitor compound; or (i) a blocker compound (ii) an inhibitor compound and (iii) a stabilizer compound are combined simultaneously or sequentially.

26. The method of claim 25, further comprising adding an organic solvent to the inhibitor compound, the retarder compound, the stabilizer compound, or any combination thereof.

27. A method for inhibiting polymerization of a monomer in a composition containing the monomer, the method comprising: The monomer inhibiting composition according to any one of claims 1 to 21 is added as a first composition to a second composition containing a polymerizable monomer or a compound capable of forming a polymerizable monomer to form a third composition, wherein the first composition inhibits polymerization of the polymerizable monomer in the third composition.

28. The method of claim 27, wherein the polymerizable monomer comprises a vinyl or ethylenically unsaturated group.

29. The method of claim 27, 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, alpha-methylstyrene, methacrylonitrile, styrene, styrene sulfonic acid, vinyltoluene, and vinylpyridine.

30. The method of claim 27, wherein the second composition comprises one or more non-polymerizable hydrocarbons.

31. The method of claim 27, wherein the third composition comprises a molar amount of the polymerizable monomer greater than a molar amount of any one or more of the inhibitor, retarder and / or stabilizer compounds.

32. The method of claim 27, wherein the third composition comprises the polymerizable monomer in an amount of 50 to 200 ppm, the inhibitor compound in an amount of 15 to 60 ppm, the retarder compound in an amount of 25 to 100 ppm, and the stabilizer compound in an amount of 1 to 15 ppm.

33. The method of claim 27, wherein the method is performed during purification or processing of one or more components of the second composition.

34. The method of claim 27, wherein the third composition is subjected to a distillation step and the stabilizer compound has a boiling point greater than a boiling point of the polymerizable monomer.

35. The method of claim 27, wherein the method is performed prior to storing or transporting the second composition.

36. The method of claim 35, wherein the first composition has an ability to inhibit polymerization of the monomer more than twice as great as a composition having one or more inhibitor compounds and one or more retarder compounds but no stabilizer compound under the same conditions.

37. The method of claim 35, wherein the first composition inhibits polymerization of the monomer by more than five times.

38. The method of claim 35, wherein the first composition inhibits polymerization of the monomer by more than ten times.

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