Antifouling composition for high intensity treatment of vinyl monomer streams - Patents.com

Abstract

An inhibitor composition is provided for mitigating undesirable polymerization during processing of hydrocarbon streams loaded with reactive vinyl monomers. The polymerization inhibitor composition includes at least a first inhibitor compound including a stable nitroxide radical and a second inhibitor compound including a phenylenediamine. Methods of inhibiting polymerization of a monomer using the disclosed compositions are also provided. The method of inhibiting polymerization of a monomer includes adding the disclosed composition to the monomer. In some cases, the monomer is an ethylenically unsaturated monomer. Such ethylenically unsaturated monomers include, but are not limited to, vinyl acetate, acrylonitrile, acrylates, methacrylates, 1,3-butadiene, styrene, isoprene, (meth)acrylic acid, and combinations thereof. Methods of preparing the disclosed polymerization inhibitors and compositions are also provided.

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 comprising a stable nitroxide radical and a phenylenediamine that are useful for inhibiting the 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 included 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 are highly reactive, 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 can cause problems, leading to "fouling" of equipment, as well as contamination and consumption of products. If the resulting polymer falls out of solution during the processing stages and deposits on equipment surfaces, production efficiency is reduced. As a result of fouling of process equipment, operations must be stopped to mechanically clean the equipment and / or to remove the undesired polymer. The shutdown of operations leads to significant economic 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 the above-mentioned problems have made it mandatory to develop and use on-site chemical cleaning procedures to mitigate fouling and thereby avoid economically costly shutdowns.

[0003] Premature polymerization of these monomers is generally mitigated by administering polymerization inhibitors that can eliminate or significantly reduce premature polymerization of the monomers. Traditional polymerization inhibitors contain stable free radicals that can effectively trap and scavenge carbon-centered radicals. Operators currently use feedstocks that require high intensity operating conditions, so the use of traditional inhibitors has proven ineffective. Traditional 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), generally degrade and lose their efficacy as polymerization inhibitors under high temperature processing environments. As a result, there is a pressing need for the development of new polymerization inhibitor compositions that have high thermal stability and are therefore less susceptible to loss of inhibition function even in high temperature processes. Summary of the Invention

[0004] A composition for inhibiting monomer polymerization is provided, the composition comprising a first inhibitor compound comprising a stable nitroxide radical and a second inhibitor compound comprising a phenylenediamine.

[0005] In some embodiments, the first inhibitor compound has Formula (I): [ka] The In the formula, R 1 is C 1 ~C 22 alkyl or aryl, and the alkyl and aryl are C 1 ~C 22 It is optionally substituted with one or more alkyl or aryl.

[0006] 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-hexyl ... Methylpiperidine-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 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 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.

[0007] In some embodiments, the first inhibitor has Formula III: [ka] is a compound of In the formula, R 3 is -O or -OH, R 4 is C 1 ~C 22 alkyl or aryl, and the alkyl and aryl are C 1 ~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-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.

[0009] In some embodiments, the second inhibitor compound is a phenylenediamine of formula (IV) or formula (V): [ka] In the formula, X 1 and X 2 is independently 1 ~C 22 alkyl or aryl, and the alkyl and aryl are C 1 ~C 22It is optionally substituted with one or more alkyl or aryl.

[0010] In some embodiments, X 1 and X 2 is independently 1 ~C 22 alkyl or phenyl, and alkyl and phenyl are C 1 ~C 22 It is optionally substituted with one or more alkyl or aryl.

[0011] In some embodiments, X 1 and X 2 is independently 1 ~C 10 alkyl or phenyl, and alkyl and phenyl are C 1 ~C 22 It is optionally substituted with one or more alkyl or aryl.

[0012] In some embodiments, X 1 and X 2 is independently 1 ~C 5 alkyl or phenyl, and alkyl and phenyl are C 1 ~C 22 It is optionally substituted with one or more alkyl or aryl.

[0013] In some embodiments, 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'-di-acetyl-1,4-phenylenediamine, N-tert-butyl-N'-phenyl-1,4-phenylenediamine, N,N'-di-phenyl-1,4-phenylenediamine, and any combination thereof.

[0014] In some embodiments, the first inhibitor compound is present in the composition at a concentration of about 0.01% to about 80% by weight.

[0015] In some embodiments, the second inhibitor compound is present in the composition at a concentration of about 0.01% to about 50% by weight.

[0016] 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.

[0017] In some embodiments, the composition further comprises an organic solvent.

[0018] 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.

[0019] A method of inhibiting polymerization of a monomer is provided, the method comprising adding any of the compositions described herein to the monomer.

[0020] In some embodiments, the monomer is provided in solution.

[0021] In some embodiments, the solution further comprises one or more additional components selected from an acid, an organic solvent, and water.

[0022] In some aspects, the monomer is an ethylenically unsaturated monomer.

[0023] In some embodiments, the composition is added to the monomer such that the concentration of the first inhibitor compound is from about 0.1 ppm to about 10,000 ppm.

[0024] In some embodiments, the composition is added to the monomer such that the concentration of the second inhibitor compound is from about 0.1 ppm to about 10,000 ppm.

[0025] 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.

[0026] 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]

[0027] A detailed description of the present invention is set forth herein below with specific reference to the drawings.

[0028] [Figure 1] A comparison of the polymerization reaction rates of untreated and treated styrene solutions under static test conditions and at a high intensity reaction temperature of 135° C. is shown.

[0029] [Diagram 2] 1 shows the amount of polystyrene formed after 6 hours of polymerization reaction at a high strength temperature of about 135° C.

[0030] [Diagram 3] A comparison of styrene polymerization reaction rates under high intensity conditions is shown. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Various aspects of the present disclosure are described below. The relationship and function 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.

[0032] By increasing the process temperature beyond the typical range, antifouling agents that had previously proven effective ceased to function. The new operating conditions were characterized as high intensity. Prior to the increase to high intensity conditions, operations had continued for over eight years without an emergency shutdown to remove fouling material from the process equipment. As soon as the operating temperature was increased above the typical upper threshold, the rate of fouling increased sharply. Very frequently, operations had to be shut down as an emergency. Such unscheduled shutdowns of operations are costly. To prevent this, the development of high temperature inhibitors was necessary.

[0033] As used herein, "high intensity" refers to a condition of a distillation process where the heating medium has a temperature above a certain value. Depending on the heating medium, the temperature at which "high intensity" conditions begin may vary. If the heating medium is water / condensate, a temperature of at least about 100°C may be considered "high intensity". If the heating medium is low pressure steam, a temperature of at least about 125°C may be considered "high intensity". If the heating medium is medium pressure steam, a temperature of at least about 160°C may be considered "high intensity". If the heating medium is high pressure steam, a temperature of at least about 180°C may be considered "high intensity". If the heating medium is oil, a temperature of at least about 300°C may be considered "high intensity".

[0034] 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 a plurality of components, in addition to the aforementioned compound having a stable nitroxide radical and a phenylenediamine.

[0035] A "polymerization inhibitor" inhibits the polymerization of polymerizable monomers during an induction period under shutdown conditions in the presence of these monomers. After the polymer inhibitor is completely consumed and the induction period has elapsed, polymer formation occurs at the same rate as if no heavy inhibitor was present at all.

[0036] Polymerization inhibitors and retarders may generally be considered "polymerization inhibitors," that is compounds capable of inhibiting or reducing the formation of polymer from one or more radically polymerizable compounds.

[0037] The term "fouling" refers to the formation of polymers, prepolymers, oligomers, and / or other materials that become insoluble in the stream and / or precipitate from the stream and may deposit on the equipment under the conditions under which the equipment is operated. Similarly, the inhibitor compositions of the present disclosure may also be referred to as "anti-fouling agents" because they inhibit or reduce the formation of fouling polymers.

[0038] Compositions of the Disclosure The present disclosure relates to a composition for inhibiting monomer polymerization, comprising a first inhibitor compound comprising a stable nitroxide radical and a second inhibitor compound that is a phenylenediamine. In some aspects, the compositions used herein are particularly useful in high intensity conditions in a distillation column. In some aspects, the composition is for inhibiting monomer polymerization, and the monomer is an ethylenically unsaturated monomer. For example, the compositions of the present disclosure are 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.

[0039] In some aspects, the compositions of the present disclosure are useful for inhibiting the polymerization of ethylenically unsaturated monomers under high intensity operating conditions.

[0040] In some embodiments, the first inhibitor compound comprising a stable nitroxide radical has formula (I): [ka] is a compound of In the formula, R 1 , H, C 1 ~C 22 Alkyl, C 1 ~C 22 Alkenyl, C 1 ~C 22 Alkynyl, C 1 ~C 22 Cycloalkyl, aryl, -C 1 ~C 22 Alkylenearyl, -C(O)(C 1 ~C 22 alkyl), -C(O)(C 1 ~C 22 alkenyl), -C(O)(C 1 ~C 22 alkynyl), -C(O)(C 1 ~C 22-C(O)(cycloalkyl), -C(O)(aryl), or -C(O)(C 1 ~C 22 alkylenearyl), where alkyl, cycloalkyl, and aryl are C 1 ~C 22 Alkyl, C 1 ~C 22 Alkenyl, C 1 ~C 22 It is optionally substituted with one or more of alkynyl, or aryl.

[0041] 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."

[0042] In certain embodiments, R 1 is -C(O)(C 1 ~C 22 alkyl), -C(O)(C 1 ~C 22 alkenyl), -C(O)(C 1 ~C 22 alkynyl), -C(O)(C 1 ~C 22 -C(O)(cycloalkyl), -C(O)(aryl), or -C(O)(C 1 ~C 22 alkylenearyl), where alkyl, cycloalkyl, and aryl are C 1 ~C 22 Alkyl, C 1 ~C 22 Alkenyl, C 1 ~C 22 Optionally substituted with one or more of alkynyl, and aryl.

[0043] In some embodiments, R is C 1 ~C 22 alkyl or aryl, and the alkyl and aryl are C 1 ~C 22It is optionally substituted with one or more alkyl or aryl.

[0044] In some embodiments, R 1 is H. In some other embodiments, R 1 is C 1 ~C 22 In some embodiments, R 1 is C 1 ~C 22 In some embodiments, R is alkenyl. 1 is C 1 ~C 22 In some embodiments, R is alkynyl. 1 is C 1 ~C 22 Cycloalkyl, cycloalkyl being C 1 ~C 22 Alkyl, C 1 ~C 22 Alkenyl, C 1 ~C 22 In some embodiments, R is optionally substituted with one or more of alkynyl, aryl, or aryl. 1 is aryl, the aryl being C 1 ~C 22 Alkyl, C 1 ~C 22 Alkenyl, C 1 ~C 22 In some embodiments, R is optionally substituted with one or more of alkynyl, aryl, or aryl. 1 -C 1 ~C 22 alkylenearyl, aryl being C 1 ~C 22 Alkyl, C 1 ~C 22 Alkenyl, C 1 ~C 22 In some embodiments, R is optionally substituted with one or more of alkynyl, aryl, or aryl. 1 is -C(O)(C 1 ~C 22 In some embodiments, R 1 is -C(O)(C 1 ~C 12In some embodiments, R 1 is -C(O)(C 1 ~C 6 In some embodiments, R 1 is -C(O)(methyl). In some embodiments, R 1 is -C(O)(ethyl). In some embodiments, R 1 is -C(O)(propyl). In some embodiments, R 1 is -C(O)(butyl). In some embodiments, R 1 is -C(O)(C 1 ~C 22 alkenyl). In some embodiments, R 1 is -C(O)(C 1 ~C 22 alkynyl). In some embodiments, R 1 is -C(O)(C 1 ~C 22 cycloalkyl), where cycloalkyl is C 1 ~C 22 Alkyl, C 1 ~C 22 Alkenyl, C 1 ~C 22 In some embodiments, R is optionally substituted with one or more of alkynyl, aryl, or aryl. 1 is -C(O)(aryl), where aryl is C 1 ~C 22 Alkyl, C 1 ~C 22 Alkenyl, C 1 ~C 22 In some embodiments, R is optionally substituted with one or more of alkynyl, aryl, or aryl. 1 is -C(O)(C 1 ~C 22 alkylenearyl), wherein aryl is C 1 ~C 22 Alkyl, C 1 ~C 22 Alkenyl, C 1 ~C 22 It is optionally substituted with one or more of alkynyl, or aryl.

[0045] 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-hexyl ... Piperidine-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- 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 4-hexylpiperidine-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.

[0046] In other embodiments, the first inhibitor compound has formula (II): [ka] The In the formula, R 2 , H, C 1 ~C 22 Alkyl, C 1 ~C 22 Alkenyl, C 1 ~C 22 Alkynyl, C 1 ~C 22 Cycloalkyl, aryl, -C 1 ~C 22 Alkylene, -C(O)(C 1 ~C 22 alkyl), -C(O)(C 1 ~C 22 alkenyl), -C(O)(C 1 ~C 22 alkynyl), -C(O)(C 1 ~C 22 -C(O)(cycloalkyl), -C(O)(aryl), and -C(O)(C 1 ~C 22 alkylene), wherein alkyl, alkylene, cycloalkyl, and aryl are selected from C 1 ~C 22 Alkyl, C 1 ~C 22 Alkenyl, C 1 ~C 22 It is optionally substituted with one or more of alkynyl, or aryl.

[0047] In certain embodiments, R 2 is -C(O)(C 1 ~C 22 alkyl), -C(O)(C 1 ~C 22 alkenyl), -C(O)(C 1 ~C 22 alkynyl), -C(O)(C1 ~C 22 -C(O)(cycloalkyl), -C(O)(aryl), and -C(O)(C 1 ~C 22 alkylene), where alkyl, alkylene, cycloalkyl, and aryl are C 1 ~C 22 Alkyl, C 1 ~C 22 Alkenyl, C 1 ~C 22 It is optionally substituted with one or more of alkynyl, or aryl.

[0048] In some embodiments, R 2 is H. In some other embodiments, R 2 is C 1 ~C 22 In some embodiments, R 2 is C 1 ~C 22 In some embodiments, R is alkenyl. 2 is C 1 ~C 22 In some embodiments, R is alkynyl. 2 is C 1 ~C 22 Cycloalkyl, cycloalkyl being C 1 ~C 22 Alkyl, C 1 ~C 22 Alkenyl, C 1 ~C 22 In some embodiments, R is optionally substituted with one or more of alkynyl, aryl, or aryl. 2 is aryl, the aryl being C 1 ~C 22 Alkyl, C 1 ~C 22 Alkenyl, C 1 ~C 22 In some embodiments, R 2 -C 1 ~C 22 alkylene, the alkylene being C 1 ~C 22 Alkyl, C1 ~C 22 Alkenyl, C 1 ~C 22 In some embodiments, R is optionally substituted with one or more alkynyl or aryl that is optionally substituted with one or more aryl. 2 is -C(O)(C 1 ~C 22 In some embodiments, R 2 is -C(O)(C 1 ~C 12 In some embodiments, R 2 is -C(O)(C 1 ~C 6 In some embodiments, R 2 is -C(O)(methyl). In some embodiments, R 2 is -C(O)(ethyl). In some embodiments, R 2 is -C(O)(propyl). In some embodiments, R 2 is -C(O)(butyl). In some embodiments, R 2 is -C(O)(C 1 ~C 22 alkenyl). In some embodiments, R 2 is -C(O)(C 1 ~C 22 alkynyl). In some embodiments, R 2 is C(O)(C 1 ~C 22 cycloalkyl), where cycloalkyl is C 1 ~C 22 Alkyl, C 1 ~C 22 Alkenyl, C 1 ~C 22 In some embodiments, R is optionally substituted with one or more of alkynyl, aryl, or aryl. 2 is -C(O)(aryl), where aryl is one or more C 1 ~C 22 Alkyl, C 1 ~C 22 Alkenyl, C 1 ~C 22Optionally substituted with alkynyl, aryl, or aryl. Some embodiments include 2 is -C(O)(C 1 ~C 22 alkylene), where alkylene is C 1 ~C 22 Alkyl, C 1 ~C 22 Alkenyl, C 1 ~C 22 Optionally substituted alkynyl, or aryl which is optionally substituted with one or more aryl.

[0049] In some embodiments, the compound of formula (II) is selected from the group consisting of 2,2,6,6-tetramethylpiperine-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 ... 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-tetramethylpiperidine- 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-(naphthalen-2-yloxy)piperidin-1-ol.

[0050] In certain aspects, the compositions of the present disclosure comprise compounds of formula (I) and (II), respectively, wherein R 1 and R 2 For example, in some embodiments, the compositions of the present disclosure each comprise a compound of formula (I) and (II), wherein R 1 and R 2 are each independently -C(O)(C 1 ~C 22 In certain aspects, the compositions of the present disclosure include first and second inhibitor compounds of formula (I) and (II), respectively, where R 1 and R 2 is different.

[0051] The compounds of formula (II) of the present disclosure that bear 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, as follows: [ka]

[0052] 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, as illustrated below: [ka]

[0053] Nitroxide hydroxylamines are excellent hydrogen donors due to the weak NO-H bond in the compound, and therefore they are efficient antioxidants. As antioxidants, nitroxide hydroxylamines react readily with oxygen-centered radicals, such as peroxide radicals, which 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 nearly diffusion-controlled rate. This rate is several orders of magnitude faster than phenolic compounds. However, their kinetic advantage is not always favorable. 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.

[0054] 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 scavenge one oxygen-centered radical and one carbon-centered radical, whereas the nitroxide can only scavenge carbon-centered radicals.

[0055] In some embodiments, the first inhibitor has Formula III: [ka] is a compound of In the formula, R 3 is -O or -OH, R 4 is C 1 ~C 22 alkyl or aryl, and the alkyl and aryl are C 1 ~C22 It is optionally substituted with one or more alkyl or aryl.

[0056] In some embodiments, R 3 In some embodiments, R 3 is -OH.

[0057] Some embodiments include R 4 is C 1 ~C 22 C optionally substituted with one or more alkyl or aryl 1 ~C 22 In some embodiments, R 4 is C 1 ~C 22 Aryl is optionally substituted with one or more alkyl or aryl.

[0058] 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.

[0059] In some embodiments, the second inhibitor compound is a phenylenediamine of formula (IV) or formula (V): [ka] In the formula, X 1 and X 2 is independently 1 ~C 22 alkyl or aryl, and the alkyl and aryl are C 1 ~C 22It is optionally substituted with one or more alkyl or aryl.

[0060] 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).

[0061] Examples of phenylenediamines include, but are not limited to, 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'-di-acetyl-1,4-phenylenediamine, N-tert-butyl-N'-phenyl-1,4-phenylenediamine, and N,N'-di-phenyl-1,4-phenylenediamine.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] In some embodiments, the composition also comprises 2,2,6,6-tetramethylpiperidine-1-oxyl, 2,2,6,6-tetramethylpiperidin-1-ol, 4-hydroxy-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 also includes 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 includes 2,2,6,6-tetramethylpiperidine-1-oxyl. In some embodiments, the composition also includes 2,2,6,6-tetramethylpiperidin-1-ol. In some embodiments, the composition also includes 4-hydroxy-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.

[0069] The composition may also optionally include one or more organic solvents. Those skilled in the art will understand 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.

[0070] In some embodiments, the composition also includes one or more ethylenically unsaturated monomers. Those skilled in the art will understand 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.

[0071] The compositions of the present disclosure are stable and remain useful polymerization inhibitors even under acidic conditions.Therefore, the compositions of the present disclosure are useful for inhibiting premature polymerization of monomers during manufacturing processes, especially during processes carried out under acidic conditions.For example, the compositions of the present disclosure are useful for preventing polymerization of acrylates, which may include, but are not limited to, acrylonitrile, acrylic acid, methyl methacrylic acid and its esters, and vinyl acetate.

[0072] In some embodiments, the compositions disclosed herein do not include 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (HTEMPO). In some embodiments, the compositions disclosed herein do not include 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl (OTEMPO). In some embodiments, HTEMPO and OTEMPO are not added to the ethylenically unsaturated monomer.

[0073] Methods of Using the Disclosed Compositions 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, hi some aspects, an effective amount of a composition of the present disclosure is added to the monomer, where an effective amount is any amount sufficient to inhibit polymerization of the monomer.

[0074] 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.

[0075] The compositions of the present disclosure can be added to a fluid manually or automatically. The compositions can also be added continuously and / or intermittently. Automatic addition can be achieved by the use of a chemical injection pump. The chemical injection pump can be programmed to add a specific amount of the polymerization inhibitor composition or any component thereof to the fluid at regular time intervals. In another aspect, the chemical injection pump can be manually controlled to add a specific amount of the polymerization inhibitor composition or any component thereof to the fluid. The polymerization inhibitor composition of the present disclosure can be added to a monomer to inhibit the polymerization of the monomer.

[0076] In some embodiments, the monomers are provided as a pure liquid, while in other embodiments, the monomers are provided in a solution, hereinafter referred to as a "monomer solution."

[0077] 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.

[0078] In some embodiments, the monomer solution has a pH value of about 1 to about 7. In some embodiments, the monomer solution has a pH value of about 1 to about 6. In some embodiments, the monomer solution has a pH value of about 2 to about 6. In some embodiments, the monomer solution has a pH value of about 3 to about 6. In some embodiments, the monomer solution has a pH value of about 4 to about 6. In some embodiments, the monomer solution has a pH value of about 5 to about 6.

[0079] 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.

[0080] 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.

[0081] The disclosed method is useful for inhibiting premature polymerization of monomers during manufacturing processes, particularly during processes conducted under acidic conditions. For example, the disclosed method is useful for preventing polymerization of acrylates, which may include, but are not limited to, acrylonitrile, acrylic acid, methyl methacrylic acid and its esters, and vinyl acetate.

[0082] The methods of the present disclosure are also useful in preventing the premature polymerization of styrene during the manufacturing and purification processes.

[0083] The disclosed method is also useful in butadiene extraction processes. This utility stems from the balanced partition coefficient between the polar organic phase and the organic phase.

[0084] 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.

[0085] Process for preparing the polymerization inhibitors of the present disclosure The present invention also relates to a compound of formula (III): [ka] The process for preparing the compound of During the ceremony, R 3 is -O· or -OH, R 4 is C 1 ~C 22 Alkyl, C 1 ~C 22 Alkenyl, C 1 ~C 22 Alkynyl, C 1 ~C 22 Cycloalkyl, aryl, and C 1 ~C 22 alkylenearyl, and cycloalkyl and aryl are C 1 ~C 22 Alkyl, C 1 ~C 22 Alkenyl, C 1 ~C 22 It is optionally substituted with one or more of alkynyl, or aryl.

[0086] In some embodiments, the process for preparing a compound of formula (III) comprises reacting a compound of formula (IIIa): [ka] with a compound of formula (IIIb), [ka] In the formula, R 5 is C 1 ~C 22Alkyl or C 1 ~C 22 alkenyl, In solution, a compound of formula (III) is obtained.

[0087] In some embodiments, R 3 In some embodiments, R 3 is -OH.

[0088] In some embodiments, R 4 is C 1 ~C 22 In some embodiments, R 4 is C 1 ~C 12 In some embodiments, R 4 is C 1 In some embodiments, R 4 is ethyl. In some embodiments, R 4 is methyl.

[0089] In one embodiment, R 3 is -O· and R 4 is methyl. In another embodiment, R 3 is -O· and R 4 is ethyl. In another embodiment, R 3 is -OH, and R 4 is methyl. In another embodiment, R 3 is -OH, and R 4 is ethyl.

[0090] In some embodiments, R 5 is C 1 ~C 22 In some embodiments, R 5 is C 1 ~C 12 In some embodiments, R 5 is C 1 ~C 6 It is an alkyl.

[0091] In some embodiments, R5 is C 1 ~C 22 In some embodiments, R is alkenyl. 5 is C 1 ~C 12 In some embodiments, R is alkenyl. 5 is C 1 ~C 6 In some embodiments, R is alkenyl. 5 is C 2 It is alkenyl.

[0092] In some embodiments, the process for preparing a compound of formula (III) comprises reacting a compound of formula (IIIa): [ka] with a compound of formula (IIIc), [ka] In solution, a compound of formula (III) is obtained.

[0093] In some embodiments, the compound of formula (IIIa) is treated with a compound of formula (IIIb) in the presence of a catalyst and heat. In some embodiments, the compound of formula (IIIa) is treated with a compound of formula (IIIc) in the presence of a catalyst and heat. One skilled in the art will appreciate that there are many suitable catalysts that can be used to form a compound of formula (III) by treating a compound of formula (IIIa) with a compound of formula (IIIb) or (IIIc). For example, in some embodiments, the catalyst is an amine-containing compound. In certain embodiments, the catalyst is 4-dimethylaminopyridine, also known as DMAP. In some embodiments, the solution of the compounds of formula (IIIa) and (IIIb) or (IIIc) is heated to a temperature of about 50°C to about 100°C. In some embodiments, the solution is heated to a temperature of about 50°C to about 85°C.

[0094] In some embodiments, the process for preparing the compound of formula (III) also includes purging the solution with a nitrogen stream. In some embodiments, the step of purging the solution with a nitrogen stream is performed simultaneously with the step of treating the compound of formula (IIIa) with a compound of formula (IIIb) to obtain the compound of formula (III). In some embodiments, the step of purging the solution with a nitrogen stream is performed simultaneously with the step of treating the compound of formula (IIIa) with a compound of formula (IIIc) to obtain the compound of formula (III). In some embodiments, the step of purging the solution with a nitrogen stream is performed after the step of treating the compound of formula (IIIa) with a compound of formula (IIIb) to obtain the compound of formula (III). In some embodiments, the step of purging the solution with a nitrogen stream is performed after the step of treating the compound of formula (IIIa) with a compound of formula (IIIc) to obtain the compound of formula (III). Without wishing to be bound by theory, the step of purging the solution with a nitrogen stream may be useful for removing certain reaction by-products that drive the reaction equilibrium toward the formation of the compound of formula (III). EXAMPLES

[0095] Example 1: High strength static performance blank Commercially available styrene is shipped and stored after treatment with 4-tert-butylcatechol (TBC) to prevent gum formation. Therefore, before using the commercial styrene in the performance test, the TBC was removed by elution through an alumina column, thereby obtaining fresh styrene. Styrene was diluted with toluene to obtain a solution containing about 70% (w / w) styrene and about 30% (w / w) toluene. About 10 mL of styrene solution per tube was added to 24 pressure-resistant glass tubes. After removing dissolved oxygen in the solution by bubbling nitrogen gas through the solution for about 2 minutes, the test tubes were capped using PTFE screw caps with fluoroelastomer (FETFE) O-rings. All tubes were placed in a heat block preheated to about 135°C. After the first 15 minutes had elapsed, the four reaction tubes were withdrawn from the heat block and then withdrawn at 15-minute time intervals for a total reaction time of about 90 minutes. To quench the polymerization, the four tubes were immediately placed in an ice bath, followed by immediate dilution of the reaction mixture with toluene. A proprietary method was used to determine the concentration of soluble polymer product in the reaction mixture.

[0096] Example 2: High Strength Static Performance 25ppm HTEMPO A freshly prepared solution of commercial styrene and toluene was treated with 25 ppm HTEMPO. The kinetics of this solution was performed as described in Example 1.

[0097] Example 3: High Strength Static Performance 25 ppm 4-Acetoxy TEMPO A dosage of 25 ppm of 4-acetoxyTEMPO was added to a toluene diluted styrene solution prepared according to the procedure of Example 2. Similarly, performance tests and polymer analysis were carried out as in Example 1.

[0098] Example 4: High strength static performance 12.5 ppm HTEMPO and 12.5 ppm PDA After treating the toluene-styrene solution with 12.5 ppm HTEMPO and 12.5 ppm of the PDA prototype N,N'-di-sec-butylphenylenediamine, polymerization inhibitor performance testing was performed as outlined in the examples above.

[0099] Example 5: High strength static performance 12.5 ppm 4-acetoxyTEMPO and 12.5 ppm PDA 12.5 ppm of 4-acetoxyTEMPO and 12.5 ppm of the prototype PDA were added to a reaction solution mixture of styrene and toluene as in Example 4. Reaction kinetic studies were carried out in much the same manner as in the previous examples.

[0100] The results of the comparative study are shown in Figure 1. From this testing it is very clear that normally effective free radical polymerization inhibitors are less effective at temperatures above industrial operating conditions. HTEMPO has a short induction time when polymerization occurs at 135°C. Similarly, 4-acetoxyTEMPO shows relatively low effectiveness as an inhibitor, as shown in the kinetic trends in Figure 1.

[0101] The combined use of 12.5 ppm HTEMPO and 12.5 ppm PDA polymerization inhibitors did not result in better polymerization inhibitor performance than HTEMPO. In contrast, the addition of 12.5 ppm 4-acetoxyTEMPO and 12.5 ppm PDA to the reaction solution resulted in a very significant improvement in polymerization inhibition at the unusually high temperature of 135°C.

[0102] Example 6: CSTR performance test using existing products During the treatment and purification of reactive monomers, the process stream is continuously fed to the process column, and similarly, the same stream is transferred from the processing equipment. Thus, the operation is carried out under a continuous flow of the process stream. A continuously stirred tank reactor (CSTR) was used instead of the capped tube in the above examples to simulate the on-going process in the reboiler section or bottom of the process tower.

[0103] Commercial styrene was freshly prepared by removing t-butylcatechol using an alumina column as described above in Example 1. Instead of using pure styrene, it was necessary to dilute it with a suitable solvent having a boiling point above 150°C. Since it boils at about 162°C, p-ethyltoluene (pET) was used as a diluent. The dilution of styrene was to slow down the rate of polymerization at 135°C, the high intensity temperature in the procedure. A portion of this styrene, weighing 1400 grams, was diluted with p-ethyltoluene. To 1400 g of freshly prepared styrene, 600 g of p-ethyltoluene was added to obtain an untreated hydrocarbon stream. Thus, the solution contained about 70% (w / w) styrene and about 30'% (w / w) p-ethyltoluene. About 0.0100 grams of N,N'-di-sec-butylphenylenediamine was added to the solution, followed by about 0.0100 grams of 2,6-di-t-butylphenol. This constituted treatment of the reaction solution with approximately 100 ppm of the existing polymerization inhibitor.

[0104] Of the treated solution, approximately 65 mL was added to a continuous stirred tank reactor (CSTR). The CSTR was fitted with an inlet transfer line through which the reaction mixture was added to the reactor by a pump. An outlet transfer line was also attached to the outlet port of the CSTR. This line was fitted with a second pump which carried the effluent stream from the reactor. Both pumps were adjusted to give a CSTR residence time of approximately 15 minutes. The reactor was placed on an isomantle heat block and the reaction temperature was set to 135°C using a thermocouple probe inserted directly into the reaction mixture. No evaporation or loss of reaction solution was observed due to the high boiling point of the reaction solution caused by the addition of p-ethyltoluene. Nevertheless, a reflux device was fitted to the reactor to prevent loss of reaction solution due to evaporation. A sample of the effluent stream was collected as soon as the reaction temperature reached approximately 135°C. From that point on, samples were collected at time intervals of approximately 30 minutes. The polymer content in the effluent stream was analyzed using a proprietary method. After a total CSTR reaction time of about 6 hours, the average concentration of polystyrene was about 9019 ppm (see FIG. 2).

[0105] Example 7: CSTR performance testing using new high strength products Using the same procedure used in Example 6, a 100 ppm high strength product prototype was prepared and its performance tested. The product contained about 50% (w / w) 4-acetoxyTEMPO and about 50% (w / w) N,N'-di-sec-butylphenylenediamine. After about 6 hours, the polystyrene concentration was about 7 ppm, which is within the background polymer level of styrene under ambient conditions.

[0106] The bar graph of the results is shown in Figure 2 and the polymerization kinetics trend is shown in Figure 3. From these results, it is very clear that the prototype of the new antifouling agent composition shows significantly better polymerization inhibition efficacy than the existing one (50% (w / w) PDA and 50% (w / w) hindered phenol). The high strength polymerization inhibitor effectively inhibits polymerization at high strength temperatures.

[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 term "a" is intended to include "at least one" or "one or more." For example, "a compound" is intended to include "at least one compound" or "one or more compounds."

[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 composition for inhibiting monomer polymerization, A first inhibitor compound containing a stable nitroxide radical, A composition comprising a second inhibitor compound containing phenylenediamine.

2. The first inhibitor compound is defined by formula (I): 【Chemistry 1】 It is, In the formula, R １ However, C １ ~C ２２ Alkyl or aryl, wherein the alkyl and the aryl are C １ ~C ２２ The composition according to claim 1, wherein it is optionally substituted with one or more alkyl or aryl groups.

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 Zin-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-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-nodesiloxy-2,2,6,6-tetramethylpiperidine-1-oxy,4-nodesiloxy-2,2,6,6-tetramethylpiperidine-1-oxy Tylpiperidine-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 composition according to claim 1, selected from the group consisting of 6-tetramethyl-4-(naphthalene-2-yloxy)piperidine-1-oxy and any combination thereof.

4. The first inhibitor is given by formula III: 【Chemistry 2】 It is a compound of, wherein R ３ is -O· or -OH, and R ４ is C １ to C ２２ alkyl or aryl, and the alkyl and the aryl are optionally substituted with one or more of C １ to C ２２ alkyl or aryl, the composition 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-oxy The composition according to claim 4, selected from the group consisting of syl-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 However, independently, C １ ~C ２２ It is alkyl or aryl, and the alkyl and the aryl are C １ ~C ２２ The composition according to any one of claims 1 to 5, wherein it is optionally substituted with one or more alkyl or aryl groups.

7. The composition according to any one of claims 1 to 5, 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'-di-acetyl-1,4-phenylenediamine, N-tert-butyl-N'-phenyl-1,4-phenylenediamine, N,N'-diphenyl-1,4-phenylenediamine, and any combination thereof.

8. The composition according to any one of claims 1 to 5, wherein the first inhibitor compound is present in the composition at a concentration of about 0.01% by weight to about 80% by weight.

9. The composition according to any one of claims 1 to 5, wherein the second inhibitor compound is present in the composition at a concentration of about 0.01% to about 50% by weight.

10. The composition according to any one of claims 1 to 5, wherein the molar ratio of the first inhibitor compound to the second inhibitor compound is about 100:1 to about 1:

100.

11. The composition according to any one of claims 1 to 5, wherein the composition further comprises an organic solvent.

12. The composition according to any one of claims 1 to 5, wherein the composition 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. A method for inhibiting monomer polymerization, A method comprising adding the composition described in claim 1 to the monomer.

14. The method according to claim 13, wherein the monomer is provided in a solution.

15. The method according to claim 14, wherein the solution further comprises one or more additional components selected from an acid, an organic solvent, and water.

16. The method according to any one of claims 13 to 15, wherein the monomer is an ethylenically unsaturated monomer.

17. The method according to any one of claims 13 to 15, wherein 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.

18. The method according to any one of claims 13 to 15, wherein 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.

19. The method according to any one of claims 13 to 15, wherein the monomer is selected from the group consisting of vinyl acetate, acrylonitrile, acrylate, methacrylate, 1,3-butadiene, styrene, divinylbenzene, isoprene, cyclopentadiene, dicyclopentadiene, acrylic acid, methacrylic acid, and any combination thereof.

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