Mitigating Undesired Emulsion Polymerization During Extractive Distillation of Conjugated Diene Monomers.

Abstract

An inhibitor composition is provided for mitigating undesirable emulsion polymerization during the processing of hydrocarbon streams rich in reactive vinyl monomers. The polymerization inhibitor composition includes at least a first inhibitor compound having a stable nitroxide radical and a second inhibitor including a phenylenediamine. A method of inhibiting polymerization of a monomer using the disclosed composition is also provided. The method of inhibiting polymerization of a monomer includes adding the disclosed composition to a process stream. The process stream includes an ethylenically unsaturated monomer suspended in a bulk phase and a highly polar solvent as a turbulent distillation solvent.

Description

[Technical field]

[0001] The present disclosure relates generally to compositions comprising a blend of polymerization inhibitors and methods of use thereof. More particularly, the present disclosure relates to compositions comprising at least one compound having a stable nitroxide radical and a phenylenediamine that are useful for inhibiting emulsion polymerization of ethylenically unsaturated monomers. [Background technology]

[0002] The production of ethylenically unsaturated monomers typically involves three stages: reaction, crude product recovery, and product purification by fractional distillation. Distillation operations carried out at high temperatures are often involved in the recovery and purification stages. Ethylenically unsaturated monomers, such as styrene, butadiene, isoprene, divinylbenzene, cyclopentadiene, dicyclopentadiene, vinyl acetate, acrylate, and methacrylate monomers, are present in crude process streams or in refined products made by various chemical industrial processes. However, the monomers have high reactivity, especially at high temperatures, in the presence of oxygen, or when in contact with metal oxide surfaces. Thus, these monomer types are highly prone to undesired polymerization by radical polymerization. This problem is especially severe at high temperatures and in the presence of polymerization initiators such as organic peroxides. The resulting polymers are problematic and can lead to "fouling" of equipment and contamination and consumption of products. Production efficiency is reduced when the resulting polymers precipitate from solution during the processing stages and deposit on equipment surfaces. As a result of fouling of process equipment, operations must be suspended to mechanically clean the equipment and / or to remove the undesired polymer. Operational shutdowns lead to significant financial losses for the operator. The polymer may also remain in solution as a soluble product contaminant. Contamination may require additional processing steps to remove the contaminating polymer from the final product composition stream or from the stored product. All of the above-mentioned problems have made it mandatory to develop and use on-line chemical cleaning procedures to mitigate fouling and thereby eliminate financially costly operational interruptions.

[0003] The premature polymerization of these monomers is generally mitigated by administering a polymerization inhibitor that can eliminate or significantly reduce the premature polymerization of the monomers. Conventional polymerization inhibitors contain stable free radicals that can effectively scavenge carbon-centered radicals.

[0004] During extractive distillation of reactive conjugated diene monomers such as butadiene and isoprene, the less polar monomers are suspended in the bulk phase and in more polar solvents such as N,N-dimethyl formamide (DMF), N-methyl pyrrolidone (NMP), and acetonitrile. Unless effective inhibitors are used, the dispersed monomers undergo undesirable free radical polymerization. This leads to fouling resulting in product loss and unexpected shutdowns.

[0005] Conventional polymerization inhibitors such as 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl (HTEMPO) and 4-oxo-2,2,6,6-tetramethylpiperidin-1-oxyl (OTEMPO) are ineffective at preventing emulsion polymerization because they are substantially dispersed in the bulk phase and less dispersed in the non-polar droplets of reactive monomer. Summary of the Invention

[0006] A composition for inhibiting monomer polymerization is provided that includes a first inhibitor compound that includes a stable nitroxide radical and a second inhibitor compound that includes a phenylenediamine.

[0007] In some embodiments, the first inhibitor compound is of formula (I): [ka] In the formula, R1 is C1-C 22 alkyl or aryl, where alkyl and aryl are C1-C 22 It is optionally substituted with one or more alkyl or aryl.

[0008] In some embodiments, the first inhibitor is 1-oxyl-2,2,6,6-tetramethylpiperin-4-ol, 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-ethoxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-propoxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-butoxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-pentoxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-hexyloxy -2,2,6,6-tetramethylpiperidin-1-oxy, 4-heptyloxy-2,2,6,6-tetramethylpiperidin-1-oxy, 4-octyloxy-2,2,6,6-tetramethylpiperidin-1-oxy, 4-nonyloxy-2,2,6,6-tetramethylpiperidin-1-oxy, 4-decyloxy-2,2,6,6-tetramethylpiperidin-1-oxy, 4-undecyloxy-2,2,6,6-tetramethylpiperidin-1-oxy, 4-dodecyloxy-2,2,6,6-tetramethylpiperidin-1-oxy, 4-tride Cyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-tetradecyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-pentadecyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-hexadecyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-heptadecyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-octadecyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-nodecyloxy-2, 2,6,6-tetramethylpiperidine-1-oxy, 4-decyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-icosyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-henicosyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-docosyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-(phenoxy)2,2,6,6-tetramethylpiperidine-1-oxy, 4-(benzyloxy)-2,2,6,6-tetramethylpiperidine-1-oxy, 2,2,6,6-tetramethyl-4-(naphthalene-2-yloxy)piperidin-1-oxy, and any combination thereof.

[0009] In some embodiments, the first inhibitor is a compound of formula III: [ka] In the formula, R3 is -O· or -OH, and R4 is C1-C 22 alkyl or aryl, where alkyl and aryl are C1-C 22 It is optionally substituted with one or more alkyl or aryl.

[0010] In some embodiments, the first inhibitor is 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl acetate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl propanoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl butyrate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl pentanoate, 1-oxyl-2 ,2,6,6-tetramethylpiperidin-4-yl hexanoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl heptanoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl octanoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl nonanoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl decanate canoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl undecanoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl dodecanoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl 2-ethylhexanoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl stearate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl benzoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl palmitoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl behenoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl 4-tert-butylbenzoate, and any combination thereof.

[0011] In some embodiments, the second inhibitor compound is a phenylenediamine of formula (IV) or formula (V): [ka] In the formula, X1 and X2 are independently C1-C 22 alkyl or aryl, where alkyl and aryl are C1-C 22 It is optionally substituted with one or more alkyl or aryl.

[0012] In some embodiments, X1 and X2 are independently C1-C 22 alkyl or phenyl, where alkyl and phenyl are C1-C 22 It is optionally substituted with one or more alkyl or aryl.

[0013] In some embodiments, X1 and X2 are independently C1-C 10 alkyl or phenyl, where alkyl and phenyl are C1-C 22 It is optionally substituted with one or more alkyl or aryl.

[0014] In some embodiments, X1 and X2 are independently C1-C5 alkyl or phenyl, and alkyl and phenyl are C1-C 22 It is optionally substituted with one or more alkyl or aryl.

[0015] In some embodiments, the second inhibitor is selected from the group consisting of 1,2-phenylenediamine, 1,4-phenylenediamine, N,N'-di-methyl-p-phenylenediamine, N,N'-di-sec-butyl-1,4-phenylenediamine, N,N'-di-1,4-dimethylpentyl-1,4-phenylenediamine, N,N'-di-acetyl-1,4-phenylenediamine, N-tert-butyl-N'-phenyl-1,4-phenylenediamine, N,N'-di-phenyl-1,4-phenylenediamine, and any combination thereof.

[0016] In some embodiments, the first inhibitor compound is present in the composition at a concentration of about 0.01% to about 80% by weight.

[0017] In some embodiments, the second inhibitor compound is present in the composition at a concentration of about 0.01% to about 50% by weight.

[0018] In some embodiments, the molar ratio of the first inhibitor compound to the second inhibitor compound is from about 100:1 to about 1:100.

[0019] In some embodiments, the composition further comprises an organic solvent.

[0020] In some embodiments, the composition further comprises an ethylenically unsaturated monomer selected from the group consisting of vinyl acetate, acrylonitrile, acrylates, methacrylates, 1,3-butadiene, styrene, isoprene, acrylic acid, methacrylic acid, and any combination thereof.

[0021] A method for inhibiting monomer polymerization is provided. The method includes adding a composition to a process stream in an extractive distillation process. The composition includes a first inhibitor compound that includes a stable nitroxide radical and a second inhibitor compound that includes a phenylenediamine. The process stream includes micelles.

[0022] In some embodiments, the process stream comprises a monomer.

[0023] In some embodiments, the process stream comprises a solvent selected from DMF (N,N-dimethylformamide) / furfural, NMP (N-methylpyrrolidone), acetonitrile, and mixtures thereof. Sometimes, stratification phenomena or micelles occur in the extractive distillation process. Two immiscible layers are formed: a non-polar monomer layer and a polar solvent layer.

[0024] In some embodiments, the ethylenically unsaturated monomers partition to a greater extent into one of the at least one non-polar extractive distillation solvent as compared to the at least one polar extractive distillation solvent.

[0025] In some embodiments, the inhibitor formulation has the ability to partition from the polar solvent layer to the monomer layer and inhibit premature emulsion polymerization in both layers.

[0026] In some embodiments, the process stream further comprises at least one polar extractive distillation solvent and at least one non-polar extractive distillation solvent comprising at least one ethylenically unsaturated monomer.

[0027] In some embodiments, the at least one polar extractive distillation solvent and the at least one non-polar extractive distillation solvent are immiscible with each other.

[0028] In some embodiments, the first inhibitor or the second inhibitor partitions to a greater extent into the at least one non-polar extractive distillation solvent compared to the at least one polar extractive distillation solvent.

[0029] In some embodiments, the at least one non-polar extractive distillation solvent is selected from the group consisting of furfural, tetrahydrofuran, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, benzene, toluene, ethylbenzene, ethyltoluene, dichloromethane, tetrachloromethane, pentene, hexene, heptene, octene, nonene, decene, undecene, dodecene, tridecene, tetradecene, cyclopentane, cyclopentene, cyclohexane, cyclohexene, dicyclopentane, cyclopentadiene, dicyclohex ... Lopentadiene, ethyl acetate, ethyl propionate, ethyl butanoate, ethyl pentanoate, ethyl hexanoate, ethyl heptanoate, ethyl nonanoate, ethyl decanoate, ethyl undecanoate, ethyl dodecanoate, ethyl tridecanoate, ethyl tetradecanoate, ethyl pentadecanoate, ethyl hexadecanoate, ethyl octadecanoate, ethyl behenate, methyl acetate, methyl propionate, methyl butanoate, methyl pentanoate, methyl hexanoate, methyl heptanoate, methyl nonanoate, methyl decanoate, methyl undecanoate, methyl dodecanoate, methyl tridecanoate butyl, methyl tetradecanoate, methyl pentadecanoate, methyl hexadecanoate, methyl octadecanoate, methyl behenate, propyl acetate, propyl propionate, propyl butanoate, propyl pentanoate, propyl hexanoate, propyl heptanoate, propyl nonanoate, propyl decanoate, propyl undecanoate, propyl dodecanoate, propyl tridecanoate, propyl tetradecanoate, propyl pentadecanoate, propyl hexadecanoate, propyl octadecanoate, propyl behenate, butyl acetate, butyl propionate, butyl butanoate, butyl pentanoate butyl, hexanoate, butyl heptanoate, butyl nonanoate, butyl decanoate, butyl undecanoate, butyl dodecanoate, butyl tridecanoate, butyl tetradecanoate, butyl pentadecanoate, butyl hexadecanoate, butyl octadecanoate, butyl behenate, hexyl acetate, hexyl propionate, hexyl butanoate, hexyl pentanoate, hexyl hexanoate, hexyl heptanoate, hexyl nonanoate, hexyl decanoate, hexyl undecanoate, hexyl dodecanoate, hexyl tridecanoate, hexyl tetradecanoate, hexyl pentadecanoate,Hexyl hexadecanoate, hexyl octadecanoate, hexyl behenate, octyl acetate, octyl propionate, octyl butanoate, octyl pentanoate, octyl hexanoate, octyl heptanoate, octyl nonanoate, octyl decanoate, octyl undecanoate, octyl dodecanoate, octyl tridecanoate, octyl tetradecanoate, octyl pentadecanoate, octyl hexadecanoate, octyl octadecenoate, octyl behenate, and any combination thereof.

[0030] In some embodiments, the at least one non-polar extractive distillation solvent is an alkane, alkene, cyclic alkane, cyclic alkene, aryl, alkylaryl, arylalkyl, organic ester, ether, cyclic ether, and / or other non-polar solvent known in the art.

[0031] In some embodiments, the at least one non-polar extractive distillation solvent is selected from the group consisting of vinyl acetate, acrylonitrile, acrylates, methacrylates, 1,3-butadiene, styrene, isoprene, cyclopentadiene, dicyclopentadiene, acrylic acid, methacrylic acid, and any combination thereof.

[0032] In some embodiments, the at least one polar extractive distillation solvent is selected from N,N-dimethylformamide, furfural, N-methylpyrrolidone, acetonitrile, water, and combinations thereof.

[0033] In some aspects, the monomer is an ethylenically unsaturated monomer.

[0034] In some embodiments, the composition is added to a process stream such that the concentration of the first inhibitor compound is from about 0.1 ppm to about 10,000 ppm.

[0035] In some embodiments, the composition is added to a process stream such that the concentration of the second inhibitor compound is from about 0.1 ppm to about 10,000 ppm.

[0036] In some embodiments, the monomer is selected from the group consisting of vinyl acetate, acrylonitrile, acrylates, methacrylates, 1,3-butadiene, styrene, divinylbenzene, isoprene, cyclopentadiene, dicyclopentadiene, acrylic acid, methacrylic acid, and any combination thereof.

[0037] The foregoing has outlined rather broadly the features and technical advantages of the present disclosure so that the detailed description of the embodiments that follow may be better understood. Additional features and advantages of the present disclosure will be described hereinafter which form the subject of the claims of this application. It should be appreciated by those skilled in the art that the concept and specific aspects disclosed may be readily utilized as a basis for modifying or designing other aspects for carrying out the same purposes of the present disclosure. It should also be appreciated by those skilled in the art that such equivalent aspects do not depart from the spirit and scope of the present disclosure as set forth in the appended claims. [Brief description of the drawings]

[0038] A detailed description of the invention is set forth herein below with specific reference to the following drawings:

[0039] [Figure 1] FIG. 1 shows isoprene polymerization in DMF at 95° C.

[0040] [Diagram 2] FIG. 1 shows isoprene polymerization in heptane at 95° C. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] Various aspects of the present disclosure are described below. The relationships and functions of the various elements of the aspects can be better understood by referring to the following detailed description. However, it should be understood that the aspects are not limited to those explicitly described herein, and in some cases, details that are not necessary for understanding the aspects disclosed herein, such as conventional synthesis and / or compounding, may be omitted.

[0042] During the extractive distillation of reactive conjugated diene monomers, emulsion polymerization may occur, leading to undesirable fouling. There is a need for a polymerization inhibitor that can effectively prevent emulsion polymerization. The compositions and methods disclosed herein can prevent or reduce emulsion polymerization.

[0043] A method for inhibiting monomer polymerization is provided. The method includes adding a composition to a process stream in an extractive distillation process. The composition includes a first inhibitor compound that includes a stable nitroxide radical and a second inhibitor compound that includes a phenylenediamine. The process stream includes micelles.

[0044] As used herein, "micelles" refer to aggregations of amphiphilic molecules. Micelles are formed when unequal amounts of two immiscible liquids are agitated such that a small amount of liquid is dispersed as droplets in the bulk liquid. The dispersed droplets constitute the micelles, while the bulk liquid is the continuous phase.

[0045] The present disclosure relates to a composition comprising a blend of polymerization inhibitors and a method of using the same to inhibit the polymerization of ethylenically unsaturated monomers. The polymerization inhibitor composition of the present disclosure comprises at least one compound having a thermally and chemically stable nitroxide radical and a phenylenediamine. The polymerization inhibitor composition may be a blend of multiple components including components in addition to the aforementioned compound having a stable nitroxide radical and a phenylenediamine.

[0046] A "polymerization inhibitor" in the presence of polymerizable monomers inhibits the polymerization of these monomers during an induction period under shutdown conditions. After the induction period has elapsed after the polymerization inhibitor has been completely consumed, polymer formation occurs at the same rate as if no polymerization inhibitor was present at all.

[0047] Polymerization inhibitors and retarders may generally be considered "polymerization inhibitors," that is, compounds capable of inhibiting or reducing the formation of polymers from one or more radically polymerizable compounds.

[0048] The term "fouling" refers to the formation of polymers, prepolymers, oligomers, and / or other materials that become insoluble in a stream and / or precipitate from the stream and deposit on equipment under the conditions under which the equipment is operated. Similarly, the inhibitor compositions of the present disclosure can be referred to as "anti-fouling" because they inhibit or reduce the formation of fouling polymers.

[0049] Compositions of the Disclosure The present disclosure relates to a composition for inhibiting monomer polymerization, comprising a first inhibitor compound having a stable nitroxide radical and a second inhibitor compound that is a phenylenediamine. In some aspects, the composition used herein is particularly useful in high severity conditions in distillation columns. In some aspects, the composition is for inhibiting monomer polymerization, and the monomer is an ethylenically unsaturated monomer. For example, the composition of the present disclosure is useful for inhibiting the polymerization of ethylenically unsaturated monomers, including, but not limited to, vinyl acetate, acrylonitrile, acrylate esters, methacrylate esters, 1,3-butadiene, styrene, isoprene, acrylic acid, (meth)acrylic acid, and combinations thereof.

[0050] In some aspects, the compositions of the present disclosure are useful for inhibiting the polymerization of ethylenically unsaturated monomers under highly severe operating conditions.

[0051] In some embodiments, the first inhibitor compound having a stable nitroxide radical is a compound of formula (I): [ka] In the formula, R1 is H, C1-C 22 Alkyl, C1-C 22 Alkenyl, C1-C 22 Alkynyl, C1-C22 Cycloalkyl, aryl, -C1-C 22 Alkylenearyl, -C(O)(C1-C 22 alkyl), -C(O)(C1-C 22 alkenyl), -C(O)(C1-C 22 alkynyl), -C(O)(C1-C 22 -C(O)(cycloalkyl), -C(O)(aryl), or -C(O)(C1-C 22 alkylenearyl), where alkyl, cycloalkyl, and aryl are C1-C 22 Alkyl, C1-C 22 Alkenyl, C1-C 22 It is optionally substituted with one or more of alkynyl, or aryl.

[0052] The term "aryl" refers to monocyclic, bicyclic (fused), and tricyclic (fused or spiro) hydrocarbon ring systems having a total of 5 to 14 ring carbon atoms, where at least one ring in the system is aromatic and each ring in the system contains 3 to 7 ring carbon atoms. The term "aryl" may be used interchangeably with the term "aryl ring."

[0053] In certain embodiments, R is C(O)(C-C 22 alkyl), -C(O)(C1-C 22 alkenyl), -C(O)(C1-C 22 alkynyl), -C(O)(C1-C 22 -C(O)(cycloalkyl), -C(O)(aryl), or -C(O)(C1-C 22 alkylenearyl), where alkyl, cycloalkyl, and aryl are C1-C 22 Alkyl, C1-C 22 Alkenyl, C1-C 22 Optionally substituted with one or more of alkynyl, and aryl.

[0054] In some embodiments, R is C-C 22 alkyl or aryl, where alkyl and aryl are C1-C 22It is optionally substituted with one or more alkyl or aryl.

[0055] In some embodiments, R1 is H. In some embodiments, R1 is C1-C 22 In some embodiments, R is C-C alkyl. 22 In some embodiments, R is C-C 22 In some embodiments, R is C-C 22 Cycloalkyl, cycloalkyl being C1-C 22 Alkyl, C1-C 22 Alkenyl, C1-C 22 In some embodiments, R is aryl, and aryl is optionally substituted with one or more of C-C 22 Alkyl, C1-C 22 Alkenyl, C1-C 22 In some embodiments, R is -C, -C 22 alkylenearyl, aryl being C1-C 22 Alkyl, C1-C 22 Alkenyl, C1-C 22 In some embodiments, R is optionally substituted with one or more of C(O)(C-C 22 In some embodiments, R is C(O)(C-C 12 In some embodiments, R1 is -C(O)(C1-C6 alkyl). In some embodiments, R1 is -C(O)(methyl). In some embodiments, R1 is -C(O)(ethyl). In some embodiments, R1 is -C(O)(propyl). In some embodiments, R1 is -C(O)(butyl). In some embodiments, R1 is -C(O)(C1-C6 alkyl ... 22 In some embodiments, R is -C(O)(C-C 22 In some embodiments, R is -C(O)(C-C 22cycloalkyl), where cycloalkyl is C1-C 22 Alkyl, C1-C 22 Alkenyl, C1-C 22 In some embodiments, R is -C(O)(aryl), and aryl is C-C 22 Alkyl, C1-C 22 Alkenyl, C1-C 22 In some embodiments, R is optionally substituted with one or more of -C(O)(C-C 22 alkylenearyl), where aryl is C1-C 22 Alkyl, C1-C 22 Alkenyl, C1-C 22 It is optionally substituted with one or more of alkynyl, or aryl.

[0056] Examples of compounds of formula (I) include 1-oxyl-2,2,6,6-tetramethylpiperin-4-ol, 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-ethoxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-propoxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-butoxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-pentoxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-hexyloxy-2, 2,6,6-tetramethylpiperidin-1-oxy, 4-heptyloxy-2,2,6,6-tetramethylpiperidin-1-oxy, 4-octyloxy-2,2,6,6-tetramethylpiperidin-1-oxy, 4-nonyloxy-2,2,6,6-tetramethylpiperidin-1-oxy, 4-decyloxy-2,2,6,6-tetramethylpiperidin-1-oxy, 4-undecyloxy-2,2,6,6-tetramethylpiperidin-1-oxy, 4-dodecyloxy-2,2,6,6-tetramethylpiperidin-1-oxy, 4-tridecyl Oxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-tetradecyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-pentadecyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-hexadecyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-heptadecyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-octadecyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-nodecyloxy-2,2, 6,6-tetramethylpiperidine-1-oxy, 4-decyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-icosyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-henicosyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-docosyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-(phenoxy)2,2,6,6-tetramethylpiperidine-1-oxy, 4-(benzyloxy)-2,2,6,6-tetramethylpiperidine-1-oxy, or 2,2,6,Examples include, but are not limited to, 6-tetramethyl-4-(naphthalen-2-yloxy)piperidin-1-oxy.

[0057] In another embodiment, the first inhibitor compound is of formula (II): [ka] Wherein R2 is H, C1-C 22 Alkyl, C1-C 22 Alkenyl, C1-C 22 Alkynyl, C1-C 22 Cycloalkyl, aryl, -C1-C 22 Alkylene, -C(O)(C1-C 22 alkyl), -C(O)(C1-C 22 alkenyl), -C(O)(C1-C 22 alkynyl), -C(O)(C1-C 22 -C(O)(cycloalkyl), -C(O)(aryl), and -C(O)(C1-C 22 alkylene), where alkyl, alkylene, cycloalkyl, and aryl are selected from C1-C 22 Alkyl, C1-C 22 Alkenyl, C1-C 22 It is optionally substituted with one or more of alkynyl, or aryl.

[0058] In certain embodiments, R2 is -C(O)(C1-C 22 alkyl), -C(O)(C1-C 22 alkenyl), -C(O)(C1-C 22 alkynyl), -C(O)(C1-C 22 -C(O)(cycloalkyl), -C(O)(aryl), and -C(O)(C1-C 22 alkylene), where alkyl, alkylene, cycloalkyl, and aryl are C1-C 22 Alkyl, C1-C 22 Alkenyl, C1-C 22 It is optionally substituted with one or more of alkynyl, or aryl.

[0059] In some embodiments, R2 is H. In some other embodiments, R2 is C1-C 22 In some embodiments, R2 is C1-C 22 In some embodiments, R2 is C1-C 22 In some embodiments, R2 is C1-C 22 Cycloalkyl, cycloalkyl being C1-C 22 Alkyl, C1-C 22 Alkenyl, C1-C 22 In some embodiments, R2 is aryl, and aryl is optionally substituted with one or more of C1-C 22 Alkyl, C1-C 22 Alkenyl, C1-C 22 In some embodiments, R2 is -C1-C2-alkyl, optionally substituted with one or more of alkynyl, aryl, or aryl. 22 alkylene, the alkylene being C1-C 22 Alkyl, C1-C 22 Alkenyl, C1-C 22 In some embodiments, R2 is optionally substituted with one or more of alkynyl or aryl optionally substituted with one or more of aryl. 22 In some embodiments, R2 is C(O)(C1-C 12 In some embodiments, R2 is -C(O)(C1-C6 alkyl). In some embodiments, R2 is -C(O)(methyl). In some embodiments, R2 is -C(O)(ethyl). In some embodiments, R2 is -C(O)(propyl). In some embodiments, R2 is -C(O)(butyl). In some embodiments, R2 is -C(O)(C1-C6 alkyl ... 22 In some embodiments, R2 is -C(O)(C1-C 22 In some embodiments, R2 is -C(O)(C1-C 22 cycloalkyl), where cycloalkyl is C1-C 22 Alkyl, C1-C 22Alkenyl, C1-C 22 In some embodiments, R2 is -C(O)(aryl), and aryl is C1-C 22 Alkyl, C1-C 22 Alkenyl, C1-C 22 In some embodiments, R2 is optionally substituted with one or more of -C(O)(C1-C 22 alkylene), where alkylene is C1-C 22 Alkyl, C1-C 22 Alkenyl, C1-C 22 Optionally substituted with alkynyl, or aryl which is optionally substituted with one or more aryl.

[0060] In some embodiments, the compound of formula (II) is selected from the group consisting of 2,2,6,6-tetramethylpiperin-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-pentoxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-hexyl ... ,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 Oxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-tetradecyloxy-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-nodecyloxy-2,2,6 ,6-tetramethylpiperidin-1-ol, 4-decyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-icosyloxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-henicosyloxy-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, or 2,2,6,6-Tetramethyl-4-(naphthalene-2-yloxy)piperidin-1-ol.

[0061] In certain embodiments, the compositions of the present disclosure include compounds of formula (I) and (II), respectively, where R1 and R2 are the same. For example, in some embodiments, the compositions of the present disclosure include compounds of formula (I) and (II), respectively, where R1 and R2 are each independently -C(O)(C1-C 22 In certain embodiments, the compositions of the present disclosure include first and second inhibitor compounds of formula (I) and (II), respectively, where R1 and R2 are different.

[0062] The presently disclosed compounds of formula (II) having hydroxylamines have advantages over the corresponding nitroxides (compounds of formula (I)), such as the ability to provide additional polymerization inhibition, as described more fully below. A common synthetic route to generate hydroxylamines of nitroxides is the reduction of the corresponding nitroxide with a reducing agent, such as: [ka]

[0063] The hydroxylamines of nitroxides have the potential to provide additional polymerization inhibition in the presence of carbon- and oxygen-centered radical initiators, as compared to the corresponding nitroxides, which is illustrated as follows: [ka]

[0064] Nitroxide hydroxylamines are excellent hydrogen donors due to the weakness of the NO-H bond in the compound and are therefore efficient antioxidants. As antioxidants, nitroxide hydroxylamines react readily with oxygen-centered radicals, such as peroxide radicals, and are converted to their corresponding nitroxides. Nitroxides are generally known as the most effective inhibitors due to their excellent inhibition capabilities by scavenging carbon-centered free radicals at a rate that is mostly diffusion-controlled. This rate is several orders of magnitude faster than phenolic compounds. However, their kinetic advantage is not always advantageous. For example, they may lose their advantage when oxygen-centered radicals are present as the predominant free radical. Another problem associated with nitroxides is their consumption by non-inhibiting and undesirable reactions with process stream components or other inhibitor additives. As a result, high nitroxide inhibitor dosages are often required for a given inhibition efficacy, thereby making their use economically unattractive or even infeasible.

[0065] Essentially, each hydroxylamine of a nitroxide is equivalent to one hydrogen donor plus one nitroxide polymerization inhibitor when both oxygen- and carbon-centered radicals are present, which is an attractive incentive offered by the hydroxylamine of a nitroxide: one hydroxylamine of a nitroxide can eliminate one oxygen-centered radical and one carbon-centered radical, whereas the nitroxide can only eliminate carbon-centered radicals.

[0066] In some embodiments, the first inhibitor is a compound of formula III: [ka] In the formula, R3 is -O· or -OH, and R4 is C1-C 22 alkyl or aryl, where alkyl and aryl are C1-C 22 It is optionally substituted with one or more alkyl or aryl.

[0067] In some embodiments, R3 is -O. In some embodiments, R3 is -OH.

[0068] In some embodiments, R4 is C1-C 22 C1-C optionally substituted with one or more alkyl or aryl 22 In some embodiments, R is C-C alkyl. 22 Aryl is optionally substituted with one or more alkyl or aryl.

[0069] Examples of compounds of formula (III) include 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl acetate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl propanoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl butyrate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl pentanoate, 1-oxyl- 2,2,6,6-tetramethylpiperidin-4-yl hexanoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl heptanoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl octanoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl nonanoate, 1-oxyl-2,2,6,6-tetramethylpiperidine-4- yl decanoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl undecanoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl dodecanoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl 2-ethylhexanoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl stearate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl benzoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl palmitoate, 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl behenoate, or 1-oxyl-2,2,6,6-tetramethylpiperidin-4-yl 4-tert-butylbenzoate.

[0070] In some embodiments, the second inhibitor compound is a phenylenediamine of formula (IV) or formula (V): [ka] In the formula, X1 and X2 are independently C1-C 22 alkyl or aryl, where alkyl and aryl are C1-C 22 It is optionally substituted with one or more alkyl or aryl.

[0071] In some embodiments, the second inhibitor compound is a phenylenediamine of formula (IV). In some embodiments, the second inhibitor compound is a phenylenediamine of formula (V).

[0072] Examples of phenylenediamines include, but are not limited to, 1,2-phenylenediamine, 1,4-phenylenediamine, N,N'-di-methyl-p-phenylenediamine, N,N'-di-sec-butyl-1,4-phenylenediamine, N,N'-di-1,4-dimethylpentyl-1,4-phenylenediamine, N,N'-di-acetyl-1,4-phenylenediamine, N-tert-butyl-N'-phenyl-1,4-phenylenediamine, and N,N'-di-phenyl-1,4-phenylenediamine.

[0073] In some embodiments, the composition comprises 2,2',6,6'-tetramethylpiperidinyl-1-oxyl and an alkyl substituted 1,4-phenylenediamine.

[0074] In some embodiments, the composition consists essentially of a first inhibitor compound and a second inhibitor compound, hi other embodiments, the composition consists of an organic solvent, a first inhibitor, and a second inhibitor.

[0075] In some embodiments, the first inhibitor compound is present in the composition at a concentration of about 0.01% to about 80% by weight. In some embodiments, the first inhibitor compound is present in the composition at a concentration of about 0.01% to about 70% by weight. In some embodiments, the first inhibitor compound is present in the composition at a concentration of about 0.01% to about 60% by weight. In some embodiments, the first inhibitor compound is present in the composition at a concentration of about 0.01% to about 50% by weight. In some embodiments, the first inhibitor compound is present in the composition at a concentration of about 0.01% to about 40% by weight. In some embodiments, the first inhibitor compound is present in the composition at a concentration of about 0.01% to about 30% by weight. In some embodiments, the first inhibitor compound is present in the composition at a concentration of about 0.01% to about 20% by weight. In some embodiments, the first inhibitor compound is present in the composition at a concentration of about 0.01% to about 10% by weight.

[0076] For example, in certain embodiments, the first inhibitor compound is present in the composition at a concentration of about 0.01%, about 0.1%, about 1%, about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, or about 80% by weight.

[0077] In some embodiments, the second inhibitor compound is present in the composition at a concentration of about 0.01% to about 50% by weight. In some embodiments, the second inhibitor compound is present in the composition at a concentration of about 0.01% to about 40% by weight. In some embodiments, the second inhibitor compound is present in the composition at a concentration of about 0.01% to about 30% by weight. In some embodiments, the second inhibitor compound is present in the composition at a concentration of about 0.01% to about 20% by weight. In some embodiments, the second inhibitor compound is present in the composition at a concentration of about 0.01% to about 10% by weight.

[0078] For example, in certain embodiments, the second inhibitor compound is present in the composition at a concentration of about 0.01%, about 0.1%, about 1%, about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, or about 50% by weight.

[0079] In some embodiments, the molar ratio of the first inhibitor compound to the second inhibitor compound is about 100:1 to about 1:100. In some embodiments, the molar ratio of the first inhibitor compound to the second inhibitor compound is about 90:1 to about 1:90. In some embodiments, the molar ratio of the first inhibitor compound to the second inhibitor compound is about 80:1 to about 1:80. In some embodiments, the molar ratio of the first inhibitor compound to the second inhibitor compound is about 70:1 to about 1:70. In some embodiments, the molar ratio of the first inhibitor compound to the second inhibitor compound is about 60:1 to about 1:60. In some embodiments, the molar ratio of the first inhibitor compound to the second inhibitor compound is about 50:1 to about 1:50. In some embodiments, the molar ratio of the first inhibitor compound to the second inhibitor compound is about 40:1 to about 1:40. In some embodiments, the molar ratio of the first inhibitor compound to the second inhibitor compound is about 30:1 to about 1:30. In some embodiments, the molar ratio of the first inhibitor compound to the second inhibitor compound is about 20:1 to about 1:20. In some embodiments, the molar ratio of the first inhibitor compound to the second inhibitor compound is about 10:1 to about 1:10. In some embodiments, the molar ratio of the first inhibitor compound to the second inhibitor compound is about 1:1.

[0080] In some embodiments, the composition also comprises 2,2,6,6-tetramethylpiperidine-1-oxyl, 2,2,6,6-tetramethylpiperidin-1-ol, 4-hydroxyl-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-oxo-2,2,6,6-tetramethylpiperidin-1-ol, 4-acetamide, 4-hydroxy ... The composition further comprises one or more additional compounds selected from the group consisting of 2,2,6,6-tetramethylpiperidine-1-oxyl, 4-acetoxy-2,2,6,6-tetramethylpiperidin-1-ol, 4-propionoxy-2,2,6,6-tetramethylpiperidine-1-oxyl, 4-propionoxy-2,2,6,6-tetramethylpiperidin-1-ol, and bis((2,2,6,6-tetramethylpiperidine-1-oxyl)-4-yl)oxalate. In some embodiments, the composition also comprises 2,2,6,6-tetramethylpiperidine-1-oxyl. In some embodiments, the composition also comprises 2,2,6,6-tetramethylpiperidin-1-ol. In some embodiments, the composition also comprises 4-hydroxyl-2,2,6,6-tetramethylpiperidine-1-oxyl. In some embodiments, the composition also includes 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-ol. In some embodiments, the composition also includes 4-oxo-2,2,6,6-tetramethylpiperidin-1-oxyl. In some embodiments, the composition also includes 4-oxo-2,2,6,6-tetramethylpiperidin-1-ol. In some embodiments, the composition also includes 4-acetoxy-2,2,6,6-tetramethylpiperidin-1-oxyl. In some embodiments, the composition also includes 4-acetoxy-2,2,6,6-tetramethylpiperidin-1-ol. In some embodiments, the composition also includes 4-propionoxy-2,2,6,6-tetramethylpiperidin-1-oxyl. In some embodiments, the composition also includes 4-propionoxy-2,2,6,6-tetramethylpiperidin-1-ol.In some embodiments, the composition also includes bis((2,2,6,6-tetramethylpiperidine-1-oxyl)-4-yl) oxalate.

[0081] The composition may also optionally include one or more organic solvents. Those skilled in the art will appreciate that there are many organic solvents that are compatible with the compositions of the present disclosure. For example, in some embodiments, the one or more organic solvents are selected from vinyl acetate, dimethyl phthalate, dimethyl formamide, toluene, xylene, highly aromatic naphtha, acetonitrile, ethyl acetate, acetone, dichloromethane, tetrahydrofuran, hexane, dimethyl sulfoxide, N-methyl-2-pyrrolidone, and combinations thereof. In certain embodiments, the composition also includes vinyl acetate. In certain embodiments, the composition also includes dimethyl phthalate. In certain embodiments, the composition also includes dimethyl formamide. In certain embodiments, the composition also includes toluene. In certain embodiments, the composition also includes xylene. In certain embodiments, the composition also includes highly aromatic naphtha. In certain embodiments, the composition also includes acetonitrile.

[0082] In some embodiments, the composition also includes one or more ethylenically unsaturated monomers. Those skilled in the art will appreciate that there are many ethylenically unsaturated monomers that are compatible with the compositions of the present disclosure. For example, in some embodiments, the one or more ethylenically unsaturated monomers are selected from vinyl acetate, acrylonitrile, acrylates, methacrylates, 1,3-butadiene, styrene, isoprene, (meth)acrylic acid, and combinations thereof. In certain embodiments, the composition also includes vinyl acetate. In certain embodiments, the composition also includes acrylonitrile. In certain embodiments, the composition also includes an acrylate. In certain embodiments, the composition also includes a methacrylate. In certain embodiments, the composition also includes 1,3-butadiene. In certain embodiments, the composition also includes styrene. In certain embodiments, the composition also includes isoprene. In certain embodiments, the composition also includes (meth)acrylic acid.

[0083] In some embodiments, the compositions disclosed herein do not include 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl. In some embodiments, the compositions disclosed herein do not include 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl. In some embodiments, 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl and 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl are not added to the ethylenically unsaturated monomer.

[0084] The present disclosure also relates to a method of inhibiting polymerization of a monomer comprising adding a composition of the present disclosure to the monomer. In some aspects, an effective amount of a composition of the present disclosure is added to the monomer, the effective amount being any amount sufficient to inhibit polymerization of the monomer. The process stream comprises the monomer and micelles.

[0085] In some aspects, the monomer is an ethylenically unsaturated monomer. In some aspects, the monomer is an ethylenically unsaturated monomer selected from vinyl acetate, acrylonitrile, acrylate esters, methacrylate esters, 1,3-butadiene, styrene, divinylbenzene, isoprene, cyclopentadiene, dicyclopentadiene, acrylic acid, (meth)acrylic acid, and combinations thereof are disclosed. In some aspects, the methods disclosed herein are useful for inhibiting the polymerization of vinyl acetate. In some aspects, the methods disclosed herein are useful for inhibiting the polymerization of acrylonitrile. In some aspects, the methods disclosed herein are useful for inhibiting the polymerization of acrylate esters. In some aspects, the methods disclosed herein are useful for inhibiting the polymerization of methacrylate esters. In some aspects, the methods disclosed herein are useful for inhibiting the polymerization of 1,3-butadiene. In some aspects, the methods disclosed herein are useful for inhibiting the polymerization of styrene. In some aspects, the methods disclosed herein are useful for inhibiting the polymerization of isoprene. In some aspects, the methods disclosed herein are useful for inhibiting the polymerization of acrylic acid. In some aspects, the methods disclosed herein are useful for inhibiting the polymerization of (meth)acrylic acid.

[0086] The composition of the present disclosure can be added to the fluid manually or automatically. The composition can also be added continuously and / or intermittently. Automatic addition can be achieved by using a chemical injection pump. The chemical injection pump can be programmed to add a specific amount of the polymerization inhibitor composition or any of its components to the fluid at a certain time interval. In another aspect, the chemical injection pump can be manually controlled to add a specific amount of the polymerization inhibitor composition or any of its components to the fluid. Adding the polymerization inhibitor composition of the present disclosure to a monomer inhibits the polymerization of the monomer.

[0087] In some aspects, the monomers are provided as a neat solution, while in other aspects, the monomers are provided in a solution, hereinafter referred to as a "monomer solution."

[0088] In some embodiments, the monomer solution also includes one or more additional components selected from an acid, an organic solvent, water, and combinations thereof. For example, in some embodiments, the monomer solution includes one or more organic solvents selected from vinyl acetate, dimethyl phthalate, dimethyl formamide, toluene, ethyl toluene, xylene, highly aromatic naphtha, acetonitrile, ethyl acetate, acetone, dichloromethane, tetrahydrofuran, hexane, dimethyl sulfoxide, N-methyl-2-pyrrolidone, and combinations thereof. In some embodiments, the monomer solution includes one or more acids selected from hydrochloric acid, hydrofluoric acid, hydrobromic acid, hydroiodic acid, nitric acid, phosphoric acid, sulfuric acid, boric acid, perchloric acid, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, ethanoic acid, caprylic acid, undecylic acid, lauric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, and suberic acid. In some embodiments, the monomer solution includes water.

[0089] In some embodiments, the composition is added to the monomer such that the concentration of the first inhibitor compound is about 0.1 ppm to about 10,000 ppm. In some embodiments, the composition is added to the monomer such that the concentration of the first inhibitor compound is about 0.1 ppm to about 5,000 ppm. In some embodiments, the composition is added to the monomer such that the concentration of the first inhibitor compound is about 0.1 ppm to about 1,000 ppm. In some embodiments, the composition is added to the monomer such that the concentration of the first inhibitor compound is about 0.1 ppm to about 500 ppm.

[0090] In some embodiments, the composition is added to the monomer such that the concentration of the second inhibitor compound is about 0.1 ppm to about 10,000 ppm. In some embodiments, the composition is added to the monomer such that the concentration of the second inhibitor compound is about 0.1 ppm to about 5,000 ppm. In some embodiments, the composition is added to the monomer such that the concentration of the second inhibitor compound is about 0.1 ppm to about 1,000 ppm. In some embodiments, the composition is added to the monomer such that the concentration of the second inhibitor compound is about 0.1 ppm to about 500 ppm.

[0091] The disclosed method is useful for suppressing premature polymerization of monomers during the extraction process. During the extraction process, a solvent is used to separate the components. The polarity difference between the extraction solvent and the hydrocarbon layer leads to emulsion formation, thereby increasing the risk of emulsion polymerization.

[0092] Examples of extraction solvents include, but are not limited to, dimethylformamide (DMF), furfural, acetonitrile, N-methyl-2-pyrrolidone, and the like.

[0093] The methods of the present disclosure are also useful in preventing the premature polymerization of styrene during the manufacturing and purification processes.

[0094] The disclosed method is also useful in butadiene extraction processes. This utility stems from the balanced partition coefficient between the polar and non-polar organic phases.

[0095] In some embodiments, the compositions disclosed herein are used in the distillation purification of olefins. For example, the compositions can be added to a process stream prior to entering a distillation unit, or the compositions can be added to a process stream during a distillation unit. EXAMPLES

[0096] Working Example

[0097] Example 1: Partition coefficient

[0098] Testing was performed to compare chemicals currently utilized by industry (HTEMPO and OTEMPO) with the compositions of the present disclosure. The ester of HTEMPO 1 is 4-acetoxyl-2,2',6,6'-tetramethylpiperidinyl-1-oxyl. The ester of HTEMPO 2 is 4-propionyl-2,2',6,6'-tetramethylpiperidinyl-1-oxyl. PDA is di-sec-butyl-4,4'-phenylenediamine.

[0099] Table 1 shows the partition coefficients for several tests between different solvent combinations. [Table 1]

[0100] Example 2: Isoprene polymerization test in DMF at 95°C Commercially available isoprene was passed through an alumina column to remove the stabilizer 4-tert-butylcatechol. A 100 mL jar was charged with 0.2 g of active polymerization inhibitor, 40 mL of heptane, 40 mL of DMF, and a stir bar. The above mixture was stirred at room temperature for 30 minutes and allowed to settle for 10 minutes.

[0101] DMF phase test: A 100 mL jar was charged with 0.2 mL of the bottom layer of the previously settled two-phase mixture, 1 mL of azobisisobutyronitrile (AIBN) (0.0004 g / mL) solution, and 50 g of isoprene. DMF was added to make a total weight of 100 g of solution. Approximately 10 mL of the above mixture was added to 12 pressure tubes equipped with a stir bar and heated to 95°C. After 30 minutes and every 30 minutes thereafter, two tubes were removed from the block and cooled in an ice bath to quench the polymerization reaction. The cooled polymer solution was immediately diluted with toluene. The soluble polymer in the liquid was determined by turbidity method.

[0102] Figure 1 shows that the compositions of the present disclosure significantly reduce isoprene polymerization compared to the traditional polymerization inhibitors HTEMPO and OTEMPO. Additionally, Figure 1 shows that the combination of a stable nitroxide radical with a phenylenediamine results in a synergistic effect.

[0103] In Figures 1 and 2, "Prototype 1" is about 22% by weight of 4-acetoxyTEMPO, about 5-8% by weight of HTEMPO, HTEMPOH, and hydroxylamine of 4-acetoxyTEMPO, and about 70% DMF, "Prototype 2" is "Prototype 1" + PDA, "Commercial Product" is a 10% HTEMPO aqueous solution, and "PDA" is as defined above.

[0104] Example 3: Isoprene Polymerization Test in Heptane at 95°C

[0105] Heptane phase: A 100 mL jar was charged with 5.0 mL of the top layer of the previously settled two-phase mixture, 1 mL of AIBN (0.0004 g / mL) solution, and 50 g of isoprene. Hexane was added to make a total weight of 100 g of solution. Approximately 13 mL of the above mixture was added to 12 pressure tubes equipped with a stir bar and heated to 95°C. After 30 minutes, and every 30 minutes thereafter, two tubes were removed from the block and cooled in an ice bath to quench the polymerization reaction. The cooled polymer solution was immediately diluted with toluene. The soluble polymer in the liquid was determined by turbidity. The results can be seen in Figure 2. The data used to generate the trend line in Figure 2 can be seen in Table 2.

[0106] Table 2: Polymerization growth data in heptane phase for Figure 2 (polyisoprene w / w%) [Table 2]

[0107] All of the compositions and methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. The present invention can be embodied in many different forms, and certain preferred embodiments of the present invention are described in detail herein. The present disclosure is an exemplification of the principles of the present invention, and is not intended to limit the invention to the specific embodiments exemplified. In addition, unless expressly stated otherwise, the terms "a" or "an" are intended to include "at least one" or "one or more." For example, "an inhibitor" is intended to include "at least one inhibitor" or "one or more inhibitors."

[0108] Any ranges expressed in either absolute or approximate terms are intended to encompass both, and any definitions used herein are intended to be illustrative, not limiting. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values ​​set forth in the specific examples are reported as precisely as possible. However, any numerical value inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Moreover, all ranges disclosed herein should be understood to encompass any and all subranges subsumed therein, including all fractional and whole values.

[0109] Any composition disclosed herein can comprise, consist of, or consist essentially of any element, component, and / or ingredient disclosed herein, or any combination of two or more of the elements, components, or ingredients disclosed herein.

[0110] Any method disclosed herein may comprise, consist of, or consist essentially of any method steps disclosed herein, or any combination of two or more of the method steps disclosed herein.

[0111] The transitional phrase "comprising," which is synonymous with "including," "containing," or "characterized by," is inclusive or open-ended and does not exclude additional, unrecited elements, components, ingredients, and / or method steps.

[0112] The transitional phrase "consisting of" excludes any element, component, ingredient, and / or method step not specified in the claim.

[0113] The transitional phrase "consisting essentially of" limits the scope of the claim to certain elements, components, ingredients, and / or steps, and those that do not materially affect the basic and novel characteristics of the claimed invention.

[0114] As used herein, the term "about" refers to a cited value that is within error resulting from the standard deviation found in their respective testing measurements; where such error cannot be determined, "about" may refer, for example, to within 5% of the cited value.

[0115] Moreover, the present invention encompasses all possible combinations of any or all of the various aspects described herein. It should also be understood that various changes and modifications to the preferred embodiments of the invention described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present invention and without diminishing its intended advantages. Accordingly, such changes and modifications are intended to be covered by the appended claims.

Claims

1. A method for inhibiting monomer polymerization, This includes adding the composition to the process flow in an extraction distillation process, The composition comprises a first inhibitor compound containing a stable nitroxide radical and a second inhibitor compound containing phenylenediamine. A method wherein the process flow includes micelles.

2. The first inhibitor compound is of formula (I), 【Chemistry 1】 In the formula, R １ C １ -C ２２ It is alkyl or aryl, and the alkyl and the aryl are C １ -C ２２ The method according to claim 1, wherein the molecule is optionally substituted with one or more alkyl or aryl atoms.

3. The first inhibitor is 1-oxyl-2,2,6,6-tetramethylpiperin-4-ol, 4-methoxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-ethoxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-propoxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-butoxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-pentoxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-hexyloxy-2,2,6 ,6-tetramethylpiperidine-1-oxy,4-heptyloxy-2,2,6,6-tetramethylpiperidine-1-oxy,4-octyloxy-2,2,6,6-tetramethylpiperidine-1-oxy,4-nonyloxy-2,2,6,6-tetramethylpiperidine-1-oxy,4-decyloxy-2,2,6,6-tetramethylpiperidine-1-oxy,4-undecyloxy-2,2,6,6-tetramethylpiperidine-1-oxy,4-dodecyloxy-2,2,6,6-tetramethylpiperidine-1-oxy,4-tridecyloxy C-2,2,6,6-tetramethylpiperidine-1-oxy, 4-tetradecyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-pentadecyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-hexadecyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-heptadecyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-octadecyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-nodecyloxy-2,2 6,6-tetramethylpiperidine-1-oxy, 4-decyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-icosyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-henicosyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-docosyloxy-2,2,6,6-tetramethylpiperidine-1-oxy, 4-(phenoxy)2,2,6,6-tetramethylpiperidine-1-oxy, 4-(benzyloxy)-2,2,6,6-tetramethylpiperidine-1-oxy, 2,2,6,The method according to claim 1 or 2, selected from the group consisting of 6-tetramethyl-4-(naphthalene-2-yloxy)piperidine-1-oxy and any combination thereof.

4. The first inhibitor is a compound of formula III, 【Chemistry 2】 wherein R ３ is -O· or -OH, and R ４ is C １ -C ２２ alkyl or aryl, and the alkyl and aryl are optionally substituted with one or more of C １ -C ２２ alkyl or aryl, the method according to claim 1.

5. The first inhibitor is 1-oxyl-2,2,6,6-tetramethylpiperidine-4-ylacetate, 1-oxyl-2,2,6,6-tetramethylpiperidine-4-ylpropanoate, 1-oxyl-2,2,6,6-tetramethylpiperidine-4-ylbutyrate, 1-oxyl-2,2,6,6-tetramethylpiperidine-4-ylpentanoate, 1-oxyl-2,2,6,6-tetramethylpiperidine-4-ylpentanoate, 1-oxyl-2,2,6,6-tetramethylpiperidine-4-ylacetpropanoate, 1-oxyl-2,2,6,6-tetramethylpiperidine-4-ylpentanoate, 1-oxyl-2,2,6,6-tetramethylpiperidine-4-ylacetate, 1-oxyl-2,2,6,6-tetramethylpiperidine-4-ylpropanoate, 1-oxyl-2,2,6,6-tetramethylpiperidine-4-ylbutyrate, 1-oxyl-2,2,6,6-tetramethylpiperidine-4-ylpentanoate, 1-oxyl-2,2,6,6-tetramethylpiperidine-4-ylpentanoate, Lamethylpiperidine-4-ylhexanoate, 1-oxyl-2,2,6,6-tetramethylpiperidine-4-ylheptanoate, 1-oxyl-2,2,6,6-tetramethylpiperidine-4-yloctanoate, 1-oxyl-2,2,6,6-tetramethylpiperidine-4-ylnonanoate, 1-oxyl-2,2,6,6-tetramethylpiperidine-4-yldecanoate, 1-O The method according to claim 4, selected from the group consisting of xyl-2,2,6,6-tetramethylpiperidine-4-ylundecanoate, 1-oxyl-2,2,6,6-tetramethylpiperidine-4-yldodecanoate, 1-oxyl-2,2,6,6-tetramethylpiperidine-4-yl2-ethylhexanoate, 1-oxyl-2,2,6,6-tetramethylpiperidine-4-ylstearate, 1-oxyl-2,2,6,6-tetramethylpiperidine-4-ylbenzoate, 1-oxyl-2,2,6,6-tetramethylpiperidine-4-ylpalmitoate, 1-oxyl-2,2,6,6-tetramethylpiperidine-4-ylbehenoate, 1-oxyl-2,2,6,6-tetramethylpiperidine-4-yl4-tert-butylbenzoate, and any combination thereof.

6. The second inhibitor compound is phenylenediamine of formula (IV) or formula (V), 【Transformation 3】 In the formula, X １ and X ２ Independently, C １ -C ２２ It is alkyl or aryl, and the alkyl and aryl are C １ -C ２２ The method according to claim 1 or 2, wherein the molecule is optionally substituted with one or more alkyl or aryl atoms.

7. The method according to claim 1 or 2, wherein the second inhibitor is selected from the group consisting of 1,2-phenylenediamine, 1,4-phenylenediamine, N,N'-dimethyl-p-phenylenediamine, N,N'-di-sec-butyl-1,4-phenylenediamine, N,N'-di-1,4-dimethylpentyl-1,4-phenylenediamine, N,N'-diacetyl-1,4-phenylenediamine, N-tert-butyl-N'-phenyl-1,4-phenylenediamine, N,N'-diphenyl-1,4-phenylenediamine, and any combination thereof.

8. The method according to claim 1 or 2, wherein the first inhibitor compound is present in the composition at a concentration of about 0.01% to about 80% by weight.

9. The method according to claim 1 or 2, wherein the second inhibitor compound is present in the composition at a concentration of about 0.01% to about 50% by weight.

10. The method according to claim 1 or 2, wherein the molar ratio of the first inhibitor compound to the second inhibitor compound is about 100:1 to about 1:

100.

11. The method according to claim 1 or 2, wherein the composition further comprises an organic solvent.

12. The method according to claim 1 or 2, wherein the process flow further comprises an ethylenically unsaturated monomer selected from the group consisting of vinyl acetate, acrylonitrile, acrylate, methacrylate, 1,3-butadiene, styrene, isoprene, cyclopentadiene, dicyclopentadiene, acrylic acid, methacrylic acid, and any combination thereof.

13. The method according to claim 12, wherein the process flow further comprises at least one polar extractive distillation solvent and at least one nonpolar extractive distillation solvent, the ethylenically unsaturated monomer present therein.

14. The method according to claim 13, wherein the at least one polar extractive distillation solvent and the at least one non-polar extractive distillation solvent containing the ethylenically unsaturated monomer are immiscible with respect to each other.

15. The method according to claim 13, wherein the ethylenically unsaturated monomer is distributed to one of the at least one non-polar extractive distillation solvents to a greater extent than the at least one polar extractive distillation solvent.

16. The method according to claim 15, wherein the first inhibitor or the second inhibitor is distributed to the at least one nonpolar extractive distillate solvent to a greater extent than the at least one polar extractive distillate solvent.

17. The at least one nonpolar extractive distillation solvent is furfural, vinyl acetate, acrylonitrile, 1,3-butadiene, styrene, isoprene, cyclopentadiene, dicyclopentadiene, acrylic acid, methacrylic acid, tetrahydrofuran, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane, tetradecane, benzene, toluene, ethylbenzene, ethyltoluene, dichloromethane, tetrachloromethane, pentene, hexene, heptene, octane, nonene, decene, undecene, dodecene, tridecene, tetrachloromethane Tradecene, cyclopentane, cyclopentene, cyclohexane, cyclohexene, dicyclopentane, cyclopentadiene, dicyclopentadiene, ethyl acetate, ethyl propionate, ethyl butanoate, ethyl pentanoate, ethyl hexanoate, ethyl heptanoate, ethyl nonanoate, ethyl decanoate, ethyl undecanoate, ethyl dodecanoate, ethyl tridecanoate, ethyl tetradecanoate, ethyl pentadecanoate, ethyl hexadecanate, ethyl octadecanoate, ethyl behenate, methyl acetate, methyl propionate, methyl butanoate, methyl pentanoate, Methyl xanoate, methyl heptanoate, methyl nonanoate, methyl decanoate, methyl undecanoate, methyl dodecanoate, methyl tridecanoate, methyl tetradecanoate, methyl pentadecanoate, methyl hexadecanate, methyl octadecanoate, methyl behenate, propyl acetate, propyl propionate, propyl butanoate, propyl pentanoate, propyl hexanoate, propyl heptanoate, propyl nonanoate, propyl decanoate, propyl undecanoate, propyl dodecanoate, propyl tridecanoate, propyl tetradecanoate, propyl pentadecanoate, hexadeca Propyl acetate, propyl octadecanoate, propyl behenate, butyl acetate, butyl propionate, butyl butanoate, butyl pentanoate, butyl hexanoate, butyl heptanoate, butyl nonanoate, butyl decanoate, butyl undecanoate, butyl dodecanoate, butyl tridecanoate, butyl tetradecanoate, butyl pentadecanoate, butyl hexadecanate, butyl octadecanoate, butyl behenate, hexyl acetate, hexyl propionate, hexyl butanoate, hexyl pentanoate, hexyl hexanoate, hexyl heptanoate, hexyl nonanoate, hexyl decanoate,The method according to claim 13, selected from the group consisting of hexyl undecanoate, hexyl dodecanoate, hexyl tridecanoate, hexyl tetradecanoate, hexyl pentadecanoate, hexyl hexadecanate, hexyl octadecanoate, hexyl behenate, octyl acetate, octyl propionate, octyl butanoate, octyl pentanoate, octyl hexanoate, octyl heptanoate, octyl nonanoate, octyl decanoate, octyl undecanoate, octyl dodecanoate, octyl tridecanoate, octyl tetradecanoate, octyl pentadecanoate, octyl hexadecanate, octyl octadecenoate, octyl behenate, and any combination thereof.

18. The method according to claim 13, wherein the at least one polar extraction distillation solvent is selected from N,N-dimethylformamide, furfural, N-methylpyrrolidone, acetonitrile, water, and combinations thereof.

19. The method according to claim 1 or 2, wherein the composition is added to the process stream such that the concentration of the first inhibitor compound is about 0.1 ppm to about 10,000 ppm.

20. The method according to claim 1 or 2, wherein the composition is added to the process stream such that the concentration of the second inhibitor compound is about 0.1 ppm to about 10,000 ppm.

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