Methods and compositions for removing polymeric foulants - Patents.com

Abstract

A composition and method for dissolving foulants formed in a monomer production process is provided. The composition may include an amide-containing compound and a solvent. Other ingredients, such as a polymerization inhibitor or a dispersant, may optionally be included in the composition. The amide-containing compound may be, for example, dimethylacetamide. The solvent may be, for example, methanol or toluene. The foulant includes a polymer.

Description

[Technical field]

[0001] The present disclosure relates generally to monomer production processes. More particularly, the present disclosure relates to methods and compositions for dissolving polymeric foulants produced during monomer production processes. [Background technology]

[0002] Polymerization of methyl methacrylate, methacrylic acid, methacrylamide, or other monomers, although undesirable, is very common in processes for producing these monomers. In the methyl methacrylate production process, the polymer formed from methyl methacrylate, methacrylic acid, and other monomers flows out of the process along with the spent media. Much of the polymer formed has a lower density than the spent media and can therefore float and accumulate on equipment, which can result in operational problems.

[0003] Common methods used to combat polymeric fouling include the use of inhibitors to inhibit the formation of oligomers. Methods may also include applying dispersants to the medium. However, these methods have limited effectiveness when the amount of polymer in the medium is high. Although these methods of preventing fouling are effective to various degrees, they can be time-consuming and / or expensive to implement. Furthermore, their efficiency in removing or preventing fouling tends to be low. Summary of the Invention

[0004] The present disclosure provides methods and compositions for dissolving polymeric foulants formed during monomer production processes.

[0005] In some embodiments, the present disclosure provides a method of dissolving a polymer in a monomer production process, the method comprising adding a composition to a medium in the process, the composition comprising an amide-containing compound, and the medium comprising a polymer, the method further comprising contacting the amide-containing compound with the polymer to dissolve the polymer.

[0006] In some embodiments, the amide-containing compound comprises the formula: [ka] wherein R1, R2, and R3 are independently selected from hydrogen, an alkyl group, an alkenyl group, and an aryl group. In some embodiments, at least two of R1, R2, and R3 are CH3.

[0007] In certain embodiments, the amide-containing compound comprises the formula: [ka]

[0008] In some embodiments, the amide-containing compound has a weight average molecular weight of about 45 g / mol to about 300 g / mol.

[0009] In certain embodiments, the composition comprises at least two different amide-containing compounds.

[0010] In some embodiments, the monomer is selected from the group consisting of acrylic acid, methacrylic acid, acrylates, methacrylic acid esters, acrylonitrile, and any combination thereof.

[0011] In some embodiments, the composition further comprises a solvent, which may be selected from, for example, hydrocarbons, ethers, esters, alcohols, tetrahydrofuran, and any combination thereof.

[0012] In certain embodiments, the solvent is selected from the group consisting of a hydrocarbon, tetrahydrofuran, an ether, and any combination thereof, and the monomer is acrylic acid.

[0013] In certain embodiments, the solvent is selected from the group consisting of alcohols, hydrocarbons, and any combination thereof, and the monomer is selected from the group consisting of methacrylic esters, acrylates, and any combination thereof.

[0014] In some embodiments, the hydrocarbon comprises from about 5 to about 20 carbon atoms. In certain embodiments, the hydrocarbon is selected from toluene, kerosene, or any combination thereof.

[0015] In some embodiments, the composition comprises from about 10% to about 90% by weight of the amide-containing compound, and from about 90% to about 10% by weight of the solvent.

[0016] In some embodiments, the component of the monomer production process comprises the medium, hi certain embodiments, the component is selected from the group consisting of an absorption column, a recovery column, a purification column, a stripper, a product column, a reboiler, a spent acid tank, a conduit connecting any of the aforementioned components, and any combination thereof.

[0017] In some embodiments, the composition is added to the medium continuously or intermittently.

[0018] In some embodiments, the composition is combined with alkaline wash water in a weight ratio of about 1:10 to about 1:1 and added to the medium.

[0019] In certain embodiments, the composition and dissolved polymer are removed from the medium.

[0020] In some embodiments, about 10 ppm to about 10,000 ppm of the amide-containing compound is added to the medium, hi some embodiments, the medium comprises about 0.5% to about 5% by weight of the amide-containing compound.

[0021] In certain embodiments, the composition further comprises a polymerization inhibitor, and / or a dispersing agent.

[0022] 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 conception and specific embodiments disclosed may be readily utilized as a basis for modifying or designing other embodiments for carrying out the same purposes of the present disclosure. It should also be appreciated by those skilled in the art that such equivalent embodiments do not depart from the spirit and scope of the present disclosure as set forth in the appended claims. [Brief description of the drawings]

[0023] A detailed description of the invention is set forth herein below with specific reference to the following drawings.

[0024] [Figure 1] FIG. 1 shows a schematic diagram of one embodiment of the present disclosure for a water separation column.

[0025] [Diagram 2] FIG. 1 shows a schematic diagram of one embodiment of the present disclosure relating to a used acid tank. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Various embodiments are described below, some with reference to the drawings. The relationships and functions of the various elements of the embodiments may be better understood by reference to the detailed description that follows. However, the embodiments are not limited to those illustrated in the drawings and / or set forth below. It should be understood that the drawings are not necessarily to scale, and in some cases, details that are not necessary for an understanding of the embodiments disclosed herein may be omitted.

[0027] Unless otherwise indicated, the alkyl groups described herein alone or as part of another group are optionally substituted linear or branched saturated monovalent hydrocarbon substituents containing, for example, from 1 to about 60 carbon atoms in the main chain, e.g., from 1 to about 30 carbon atoms. Examples of unsubstituted alkyl groups include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, s-butyl, t-butyl, n-pentyl, i-pentyl, s-pentyl, t-pentyl, and the like.

[0028] The term "aryl" or "ar" as used herein alone or as part of another group (e.g., arylene) refers to an optionally substituted homocyclic aromatic group, such as a monocyclic or bicyclic group containing about 6 to about 12 carbons in the ring portion, such as phenyl, biphenyl, naphthyl, substituted phenyl, substituted biphenyl, or substituted naphthyl. The term "aryl" also includes heteroaryl functional groups. It is understood that the term "aryl" applies to cyclic substituents that are planar and contain 4n+2n electrons according to Huckel's rule.

[0029] "Cycloalkyl" refers to a cyclic alkyl substituent containing, for example, about 3 to about 8 carbon atoms, preferably about 4 to about 7 carbon atoms, and more preferably about 4 to about 6 carbon atoms. Examples of such substituents include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and the like. Cyclic alkyl groups can be unsubstituted or can be further substituted with alkyl groups, such as methyl groups, ethyl groups, and the like.

[0030] The compounds of the present disclosure may be substituted with suitable substituents. The term "suitable substituents" as used herein is intended to mean chemically acceptable functional groups, preferably moieties that do not negate the activity of the compound. Such suitable substituents include, but are not limited to, halo groups, perfluoroalkyl groups, perfluoroalkoxy groups, alkyl groups, alkenyl groups, alkynyl groups, hydroxy groups, oxo groups, mercapto groups, alkylthio groups, alkoxy groups, aryl or heteroaryl groups, aryloxy or heteroaryloxy groups, aralkyl or heteroaralkyl groups, aralkoxy or heteroaralkoxy groups, HO-(C=O)- groups, heterocyclic groups, cycloalkyl groups, amino groups, alkyl and dialkylamino groups, carbamoyl groups, alkylcarbonyl groups, alkoxycarbonyl groups, alkylaminocarbonyl groups, dialkylaminocarbonyl groups, arylcarbonyl groups, aryloxycarbonyl groups, alkylsulfonyl groups, and arylsulfonyl groups. In some embodiments, suitable substituents include halogen, unsubstituted C1-C 12 Alkyl group, unsubstituted C4-C6 aryl group, or unsubstituted C1-C 10 Those skilled in the art will recognize that many of the substituents may be substituted with additional substituents.

[0031] The term "substituted" as in "substituted alkyl" means that in the group (i.e., the alkyl group), at least one hydrogen atom bonded to a carbon atom is substituted with a hydroxy (-OH), alkylthio, phosphino, amido (-CON(R A )(R B )(wherein, R A and R B are independently hydrogen, alkyl, or aryl), amino (-N(R A )(R B )(wherein, R A and R B are independently hydrogen, alkyl, or aryl), halo (fluoro, chloro, bromo, or iodo), silyl, nitro (-NO2), ether (-OR A (In the formula, R Ais alkyl or aryl), esters (-OC(O)R A (In the formula, R A is alkyl or aryl), keto (-C(O)R A (In the formula, R A means substituted with one or more substituents, such as alkyl or aryl, heterocyclo, etc.

[0032] Where the term "substituted" introduces a list of possible substituents, it is intended that the term apply to all members of that group, i.e., the phrase "optionally substituted alkyl or aryl" should be interpreted as "optionally substituted alkyl or optionally substituted aryl."

[0033] The terms "polymer," "copolymer," "polymerize," "copolymerize," and the like, include not only polymers that contain two monomer residues and polymerize two different monomers together, but also (co)polymers that contain more than two monomer residues and polymerize more than two or more other monomers together. For example, polymers disclosed herein include terpolymers, tetrapolymers, polymers that contain more than four different monomers, and polymers that comprise, consist of, or consist essentially of two different monomer residues. In addition, "polymers" disclosed herein can also include homopolymers, which are polymers that contain a single type of monomer unit.

[0034] Unless otherwise specified, the polymers of the present disclosure may be linear, branched, crosslinked, structured, synthetic, semi-synthetic, natural, and / or functionally modified. The polymers of the present disclosure may be in the form of, for example, a solution, a dry powder, a liquid, or a dispersion.

[0035] The terms "foul" and "fouling" refer to the process of forming, adding, and / or depositing a layer of foreign matter on the surfaces of equipment.

[0036] The term "foulant" refers to a layer or deposit of foreign matter on a surface of an apparatus. Foulants may be suspended, dissolved, and / or dispersed in a medium. Generally, foulants may be formed from an agglomeration of polymers and may optionally include inorganic materials.

[0037] The term "dissolve" or "dissolving" means that the foulants are reduced from agglomerates to polymer particles (groups of one or more polymers). The polymer particles may transition from a solid phase to a liquid phase. In some aspects, dissolving includes breaking down the polymers and / or reducing their molecular weight. Once dissolved, the foulants can be removed, for example, through the process stream. In some embodiments, dissolving the agglomerates includes dispersing the polymer particles in the process stream.

[0038] The terms "wt. %, "vol. %, " or "mole %" refer to the weight, volume, or mole percentage, respectively, of a component based on the total weight, volume, or moles of a material that includes the component.

[0039] In an exemplary embodiment, a method of dissolving a polymer in a monomer production process is provided. The method includes adding a composition to a medium in the process, the composition including an amide-containing compound, and the medium including a polymer. The amide-containing compound contacts the polymer to dissolve it.

[0040] Without being bound by theory, it is believed that the process of dissolving the polymer occurs as follows: the amide-containing compound and the foulants formed from polymers such as methyl methacrylate, acrylic acid, acrylonitrile, etc. have similar solubility properties. The foulants may resemble entangled polymer chains, like a ball of twisted yarn. First, the amide-containing compound penetrates the foulants and loosens the molecular chains. Second, the loosened polymer and / or polymer particles transition from a solid phase to a liquid phase. At the same time, the amide-containing compound is released into the medium. Finally, the dissolved polymer and amide-containing compound can be removed, for example, by a process stream formed from the medium.

[0041] The methods and compositions of the present disclosure are useful in connection with any process used to manufacture one or more reactive monomers. For example, if the manufacturing process produces one or more monomers that can polymerize or self-polymerize, the methods and compositions of the present disclosure may be useful in such processes. In some aspects, the reactive monomer is selected from the group consisting of acrylic acid, methacrylic acid, acrylates, methacrylic acid esters, acrylonitrile, and any combination thereof.

[0042] composition The compositions disclosed herein include an amide-containing compound. In some embodiments, the composition may include a solvent. The amide-containing compound may be present in the composition at about 10% by weight to about 100% by weight of the composition, and the solvent may be present at about 90% by weight to about 0% by weight of the composition. For example, the amide-containing compound may be present at about 10% by weight to about 100% by weight, about 15% by weight to about 100% by weight, about 20% by weight to about 100% by weight, about 25% by weight to about 100% by weight, about 30% by weight to about 100% by weight, about 35% by weight to about 100% by weight, about 40% by weight to about 100% by weight, about 45% by weight to about 100% by weight, about 50% by weight to about 100% by weight, or about 60% by weight to about 100% by weight. %, about 55% to about 100%, about 60% to about 100%, about 65% to about 100%, about 70% to about 100%, about 75% to about 100%, about 80% to about 100%, about 85% to about 100%, about 90% to about 100%, or about 95% to about 100% by weight. In some embodiments, the amide-containing compound is about 25% to about 75%, about 30% to about 70%, about 35% to about 65%, about 40% to about 60%, or about 45% to about 55% by weight of the composition. In some embodiments, the amide-containing compound is about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 80%, about 85%, about 90%, about 95%, or about 100% by weight of the composition.

[0043] In some embodiments, the composition comprises two or more amide-containing compounds. For example, the composition may comprise at least two different amide-containing compounds. In some embodiments, the composition comprises three, four, five, or more amide-containing compounds.

[0044] The composition may include a solvent. The solvent may be present in an amount of about 90% by weight to about 0% by weight, about 85% by weight to about 0% by weight, about 80% by weight to about 0% by weight, about 75% by weight to about 0% by weight, about 70% by weight to about 0% by weight, about 65% by weight to about 0% by weight, about 60% by weight to about 0% by weight, about 55% by weight to about 0% by weight, about 50% by weight to about 0% by weight, about 45% by weight to about 0% by weight, about 40% by weight to about 0% by weight, about 35% by weight to about 0% by weight, about 30% by weight to about 0% by weight, about 25% by weight to about 0% by weight, about 20% by weight to about 0% by weight, about 15% by weight to about 0% by weight, about 10% by weight to about 0% by weight, or about 5% by weight to about 0% by weight of the composition. In some embodiments, the solvent is present at about 95% to about 5%, about 90% to about 10%, about 85% to about 15%, about 80% to about 20%, about 75% to about 25%, about 70% to about 30%, about 65% to about 35%, about 60% to about 40%, or about 55% to about 45% by weight of the composition. In some embodiments, the solvent may be present at about 0.001%, 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%, about 80%, about 85%, or about 90% by weight of the composition.

[0045] In some embodiments, the amide-containing compound has a weight average molecular weight of about 45 g / mol to about 300 g / mol, about 50 g / mol to about 275 g / mol, about 55 g / mol to about 250 g / mol, about 60 g / mol to about 225 g / mol, about 65 g / mol to about 200 g / mol, about 70 g / mol to about 175 g / mol, about 75 g / mol to about 150 g / mol, about 100 g / mol to about 125 g / mol, about 73 g / mol to about 270 g / mol, or about 73 g / mol to about 120 g / mol. In some embodiments, the amide-containing compound is about 45 g / mol, about 50 g / mol, about 55 g / mol, about 60 g / mol, about 65 g / mol, about 70 g / mol, about 75 g / mol, about 80 g / mol, about 85 g / mol, about 90 g / mol, about 95 g / mol, about 100 g / mol, about 105 g / mol, about 110 g / mol, about 115 g / mol, about 120 g / mol, about 125 g / mol, about 130 g / mol, about 135 g / mol, about 140 g / mol, about 145 g / mol, about 150 g / mol, about 155 g / mol, about 160 g / mol, about 165 g / mol, about 170 g / mol, about 180 g / mol, about 190 g / mol, about 200 g / mol, about 210 g / mol, about 220 g / mol, about 230 g / mol, about 240 g / mol, about 250 g / mol, about 260 g / mol, about 270 g / mol, about 280 g / mol, about 290 g / mol, about 300 g / mol, about 310 g / mol, about 320 g / mol, about 330 g / mol, about 340 g / mol, about 350 g / mol, about 360 g / mol, about 370 g / mol, about 380 g / mol, about 390 g / mol, about 400 g / mol, about 410 g / mol, about 420 g / mol, about 430 g / mol, about 440 g / mol, about 450 g / mol, about 460 g / mol, about 470 g / mol, about 480 g / 150 g / mol, about 160 g / mol, about 175 g / mol, about 180 g / mol, about 185 g / mol, about 190 g / mol, about 195 g / mol, about 200 g / mol, about 205 g / mol, about 210 g / mol, about 215 g / mol, about 220 g / mol, about 225 g / mol, about 230 g / mol, about 235 g / mol, about 240 g / mol, about 245 g / mol, about 250 g / mol, about 260 g / mol, about 265 g / mol, about 270 g / mol, about 275 g / mol, about 280 g / mol, about 285 g / mol, about 290 g / mol, about 295 g / mol, or about 300 g / mol. In some embodiments, the molecular weight of the amide-containing compound is about 45 g / mol, about 73 g / mol, about 120 g / mol, about 270 g / mol, or about 300 g / mol.

[0046] In some embodiments, the amide-containing compound comprises the structure of Formula I: [ka]

[0047] In some embodiments, R1, R2, and R3 are independently selected from the group consisting of hydrogen, alkyl, alkenyl, and aryl. In some embodiments, at least one of R1, R2, or R3 is CH3. In another aspect, at least two of R1, R2, or R3 are CH3. In an exemplary embodiment, the amide-containing compound comprises the structure of formula II. [ka]

[0048] In another embodiment, the amide-containing compound is selected from the group consisting of dimethylformamide "DMF" (CAS number 68-12-2), dimethylacetamide "DMAC" (CAS 127-19-5), and N,N-diethylpropionamide (CAS 1114-51-8).

[0049] When R1, R2, or R3 is alkyl, the alkyl may contain 1 to 60 carbon atoms, 1 to 50 carbon atoms, 1 to 40 carbon atoms, 1 to 30 carbon atoms, 1 to 25 carbon atoms, 1 to 20 carbon atoms, 1 to 15 carbon atoms, 1 to 10 carbon atoms, or 1 to 5 carbon atoms. In some embodiments, R1, R2, and / or R3 is a C1 alkyl, a C2 alkyl, a C3 alkyl, a C4 alkyl, a C5 alkyl, a C6 alkyl, a C7 alkyl, a C8 alkyl, a C9 alkyl, or a C1 alkyl. 10 It is an alkyl.

[0050] When R1, R2, or R3 is alkenyl, the alkenyl may contain 1 to 60 carbon atoms, 1 to 50 carbon atoms, 1 to 40 carbon atoms, 1 to 30 carbon atoms, 1 to 25 carbon atoms, 1 to 20 carbon atoms, 1 to 15 carbon atoms, 1 to 10 carbon atoms, or 1 to 5 carbon atoms. In some embodiments, R1, R2, and / or R3 is C1 alkenyl, C2 alkenyl, C3 alkenyl, C4 alkenyl, C5 alkenyl, C6 alkenyl, C7 alkenyl, C8 alkenyl, C9 alkenyl, or C 10 It is alkenyl.

[0051] The solvent may be selected from the group consisting of a hydrocarbon, an ether, an ester, an alcohol, tetrahydrofuran, and any combination thereof. When the solvent comprises a hydrocarbon, the hydrocarbon may comprise from about 5 to about 25 carbon atoms, from about 5 to about 20 carbon atoms, from about 5 to about 15 carbon atoms, or from about 5 to about 10 carbon atoms. In some embodiments, the solvent comprises a hydrocarbon selected from toluene, kerosene, xylene, and any combination thereof.

[0052] In an exemplary embodiment, the solvent is selected from the group consisting of a hydrocarbon, tetrahydrofuran, an ether, and any combination thereof, and the monomer is acrylic acid. In another exemplary embodiment, the solvent is selected from the group consisting of an alcohol, a hydrocarbon, and any combination thereof, and the monomer is selected from the group consisting of a methacrylic acid ester, an acrylate, and any combination thereof.

[0053] Methods of using the composition The compositions disclosed herein may be used, for example, in a monomer manufacturing process or any process that may include reactive monomers. The compositions may be added to a medium in the process. The medium includes a foulant. The amide-containing compound of the composition contacts and dissolves the foulant.

[0054] The monomer manufacturing process may include a plurality of components, and the components may include a medium. The composition may be added continuously to the medium. In some embodiments, the composition may be added continuously or intermittently to the medium. In certain embodiments, the composition may be added during a wash cycle of the manufacturing component. When added to the wash cycle, the composition may be combined with alkaline wash water to form a mixture having a weight ratio of about 1:10 (composition to wash solution) to about 1:1 before being introduced into the manufacturing component. In some aspects, a mixture of the composition and alkaline wash water is added to the medium.

[0055] The composition may be added to the medium manually, automatically, or a combination thereof. In some embodiments, the composition is added to the medium and / or directly to a component of the monomer production process. The composition may be injected into the medium and / or one or more components. The component may include the medium. As an example, the composition may be injected into a supply pipeline and / or a toluene pipeline. The medium may contain, for example, crude acrylic acid or a solvent.

[0056] In some embodiments, the component is selected from the group consisting of an absorption column, a stripper, a recovery column, a purification column, a product column, a reboiler, a spent acid tank, a feed pipeline, a toluene pipeline, one or more trays in the headstream, a conduit connecting any of the aforementioned components, and any combination thereof.

[0057] The location of addition of the composition may be selected, for example, based on the presence or suspected presence of foulants. In some embodiments, the composition may be added to a location in the monomer production process that is upstream of a location containing foulants. In some embodiments, the composition is added, for example, by direct injection to a location blocked by foulants.

[0058] The foulants may have a volume that is not suitable for removal by a dispersant. In some embodiments, the foulants are less than about 0.5 mL in volume. 3 ~about 50mL 3 , about 0.5mL 3 ~about 45mL 3 , about 0.5mL 3 ~ approx. 40mL 3 , about 0.5mL 3 ~about 35mL 3 , about 0.5mL 3 ~About 30mL 3 , about 0.5mL 3 ~about 25mL 3 , about 0.5mL 3 ~about 20mL 3 , about 0.5mL 3~about 15mL 3 , about 0.5mL 3 ~about 10mL 3 , or about 0.5 mL 3 ~about 5mL 3 In some embodiments, the foulant is in the range of about 0.5 mL 3 , about 1 mL 3 , about 1.5mL 3 , about 2mL 3 , about 2.5mL 3 , about 3mL 3 , about 3.5mL 3 , about 4 mL 3 , about 4.5mL 3 , about 5mL 3 , about 5.5mL 3 , about 6 mL 3 , about 6.5mL 3 , about 7mL 3 , about 7.5mL 3 , about 8 mL 3 , about 8.5mL 3 , about 9 mL 3 , about 9.5mL 3 , about 10mL 3 , about 10.5mL 3 , about 11mL 3 , about 11.5mL 3 , about 12mL 3 , about 12.5mL 3 , about 13mL 3 , about 13.5mL 3 , about 14mL 3 , about 14.5mL 3 , or about 15 mL 3 It has a volume of .

[0059] When the composition contacts the foulant, the polymer of the foulant dissolves and the dissolved polymer and components of the composition can be removed from the medium, in some embodiments, the components of the composition and the dissolved polymer flow with the medium and exit the composition and can be collected, for example, in a waste container.

[0060] 1 shows an example of the disclosure that includes a water separation column 11. Column 11 may be part of a monomer production process, such as an acrylic acid production process. The composition may be injected 13a and / or 13b, for example, from a toluene tank 7 into a supply pipeline 3 or a toluene make-up pipeline 5. The product from the water separation column exits through a precut column 9.

[0061] 2 shows a spent acid tank 15, which stores spent acid and foulants, such as polymerized methacrylate from a methyl methacrylate manufacturing process. The foulants sink to the bottom and clog the pipeline 21 to the incinerator 17. However, the clogs can be dissolved / removed by contact with a composition disclosed herein. For example, compositions may be added to the feed stream 19 from the reactor, to the spent acid tank 15, and / or to the pipeline 21 to the incinerator 17 at 13c and / or 13d.

[0062] Depending on the amount of foulants to be dissolved, about 10 ppm to about 10,000 ppm of the amide-containing compound is added to the medium. In some embodiments, the amide-containing compound may be added in an amount of about 10 ppm to about 1%, about 10 ppm to about 10,000 ppm, about 50 ppm to about 9,500 ppm, about 100 ppm to about 9,000 ppm, about 150 ppm to about 8,500 ppm, about 200 ppm to about 8,000 ppm, about 250 ppm to about 7,500 ppm, about 300 ppm to about 7,000 ppm, about 350 ppm to about 6,500 ppm, about 400 ppm to about 6,000 ppm, about 450 ppm to about 5,500 ppm, or about 500 ppm to about 5,000 ppm. In some embodiments, the amide-containing compound is added to a monomer manufacturing process in an amount of about 200 ppm to 2,000 ppm, or 500 ppm to 1,500 ppm. In an exemplary embodiment, the amide-containing compound may be added to a component and / or medium of the manufacturing process in an amount of about 100 ppm to 5,000 ppm. In some embodiments, the composition may be directly injected into the manufacturing process.

[0063] In some embodiments, the amount of amide-containing compound added to a monomer production process may be measured based on the weight percent of the total medium present in either a single component (e.g., a recovery column or a reboiler) or the entire monomer production process assembly. The amount of amide-containing compound added to the medium may be from about 0.5% to about 5%, from about 0.75% to about 5%, from about 1% to about 5%, from about 1.25% to about 5%, from about 1.5% to about 5%, from about 1.75% to about 5%, from about 2% to about 5%, from about 2.25% to about 5%, from about 2.5% to about 5%, from about 2.75% to about 5%, or from about 3% to about 5% by weight of the medium.

[0064] In addition to the composition, the method may further include the addition of a polymerization inhibitor and / or a dispersant. In some embodiments, the composition includes a polymerization inhibitor and / or a dispersant. Examples of polymerization inhibitors include, but are not limited to, phenolic compounds, amines, quinones, nitroxyl compounds, and certain inorganic complexes (e.g., tetramethylpiperidinoxy, copper salts, phenothiazine (PTZ), hydroquinone (HQ), and monomethylhydroquinone ether (MEHQ)). These inhibitors are designed to interrupt the polymerization reaction and prevent the formation of polymers.

[0065] Dispersants are designed to adsorb onto existing polymer particles through chemical or physical interactions and form an insulating layer on the polymer particles, thereby preventing the particles from agglomerating, thereby keeping them suspended in the process medium. Examples of dispersants include, but are not limited to, sulfonated hydrocarbons such as dodecylbenzene sulfonate, polyisobutylene succinate esters, alkylphenol ethoxylates, alkylphenol formaldehyde resins, fatty acid esters, fatty acid amides, fatty alcohol ethoxylates, polysaccharide esters, and the like.

[0066] The above may be better understood by reference to the following examples, which are intended for illustrative purposes and are not intended to limit the scope of the disclosure or its application in any way. EXAMPLES

[0067] Various compositions of the present disclosure were tested for their ability to dissolve foulants. The compositions are set forth in Tables 1 and 2.

[0068] [Table 1]

[0069] [Table 2]

[0070] Foulants containing acrylic acid polymers (referred to herein as acrylic acid foulants) were collected from a monomer manufacturing process. Two separate test tubes were set up and about 2 mL of acrylic acid foulants collected from an acrylic acid plant was added to each test tube. About 10 mL of a composition containing dimethylacetamide was added to the first test tube. As a control, about 10 mL of a solution containing a tall oil fatty acid mixture was added to the second test tube. The first test tube showed that the dimethylacetamide was able to dissolve the foulants, but the foulants in the second test tube remained aggregated and sank to the bottom of the test tube. Even after both test tubes were allowed to sit for 12 hours, the foulants remained dissolved in the first test tube.

[0071] Similar experiments were performed using a foulant containing polymerized methyl methacrylate, and other experiments were performed using a foulant containing polymerized acrylonitrile.

[0072] These experiments demonstrated that compositions containing dimethyl phthalate and dimethylacetamide at about 30% to about 100% by weight of the total composition were highly effective at dissolving foulants. In general, as the amount of dimethylacetamide added to the test tube increased, the amount of foulants dissolved increased. In some experiments, compositions containing about a 1:1 ratio of amide-containing compound and solvent effectively dissolved foulants.

[0073] Furthermore, these experiments demonstrated that compositions containing dimethyl phthalate and about 30% to about 100% by weight dimethylformamide were highly effective at dissolving foulants. In general, as the amount of dimethylformamide added to the test tube increased, the amount of dissolved foulants increased.

[0074] Experiments demonstrated the effectiveness of the composition to dissolve foulant material generated from acrylic acid and remain dissolved when added back to the acrylic acid process medium. To a first test tube, about 10 mL of acrylic acid was added. To a second test tube, about 10 mL of xylene was added. About 2.5 mL of the acrylic acid foulant solution was added to each test tube. The acrylic acid foulant solution contained dimethylacetamide and about 2 mL of dissolved foulants. The dissolved foulants did not settle or form a precipitate in either tube, even when added to a larger amount of process medium (i.e., acrylic acid or xylene).

[0075] In some cases the test tubes were shaken and in other cases the test tubes were not shaken. Shaking appeared to increase the effectiveness of the composition, but shaking was not necessary to dissolve the foulants.

[0076] 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 illustrated. In addition, unless expressly stated otherwise, the term "a" is intended to include "at least one" or "one or more." For example, "a solvent" is intended to include "at least one solvent" or "one or more solvents."

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] The transitional phrase "consisting of" excludes any element, component, ingredient, and / or method step not specified in the claim.

[0082] 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.

[0083] Unless otherwise specified, all molecular weights referred to herein are weight average molecular weights and all viscosities were measured at 25° C. using neat (undiluted) polymer.

[0084] 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.

[0085] Moreover, the present invention encompasses all possible combinations of any or all of the various embodiments 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. 1. A method for dissolving foulants in a monomer production process, the method comprising: adding a composition to a medium in the process, the composition comprising an amide-containing compound and the medium comprising the foulant; contacting the amide-containing compound with the foulant; dissolving said foulants.

2. The amide-containing compound has the following formula: 【Chemistry 1】 wherein R １ , R ２ , and R ３ 10. The method of claim 1, wherein is independently selected from the group consisting of hydrogen, an alkyl group, an alkenyl group, and an aryl group.

3. R １ , R ２ , and R ３ At least two of ３ The method of claim 2, wherein

4. The amide-containing compound has the following formula: 【Chemistry 2】 The method according to any one of claims 1 to 3, comprising:

5. The method of any one of claims 1 to 3, wherein the amide-containing compound has a weight average molecular weight of about 45 g / mol to about 300 g / mol.

6. The method of any one of claims 1 to 3, wherein the composition comprises at least two different amide-containing compounds.

7. The method of any one of claims 1 to 3, wherein the monomer is selected from the group consisting of acrylic acid, methacrylic acid, acrylates, methacrylic acid esters, acrylonitrile, and any combination thereof.

8. The method of any one of claims 1 to 3, wherein the composition further comprises a solvent.

9. 9. The method of claim 8, wherein the solvent is selected from the group consisting of hydrocarbons, ethers, esters, alcohols, tetrahydrofuran, and any combination thereof.

10. 9. The method of claim 8, wherein the solvent is selected from the group consisting of hydrocarbons, tetrahydrofuran, ethers, and any combination thereof, and the monomer is acrylic acid.

11. 9. The method of claim 8, wherein the solvent is selected from the group consisting of alcohols, hydrocarbons, and any combination thereof, and the monomer is selected from the group consisting of methacrylic acid esters, acrylates, and any combination thereof.

12. The method of claim 8, wherein the hydrocarbon contains from about 5 to about 20 carbon atoms.

13. 9. The method of claim 8, wherein the hydrocarbon is selected from toluene, kerosene, xylene, or any combination thereof.

14. 9. The method of claim 8, wherein the composition comprises from about 10% to about 90% by weight of the amide-containing compound and from about 90% to about 10% by weight of the solvent.

15. The method of any one of claims 1 to 3, wherein components of the monomer production process include the medium.

16. 16. The method of claim 15, wherein the component is selected from the group consisting of an absorption column, a stripper, a recovery column, a purification column, a product column, a reboiler, a spent acid tank, conduits connecting any of the foregoing components, and any combination thereof.

17. The method according to any one of claims 1 to 3, wherein the composition is added to the medium continuously or intermittently.

18. The method of any one of claims 1 to 3, wherein the composition is combined with alkaline wash water in a weight ratio of 1:10 to 1:1 and added to the medium.

19. The method of any one of claims 1 to 3, wherein the composition and dissolved foulants are removed from the medium.

20. The method of any one of claims 1 to 3, wherein about 10 ppm to about 10,000 ppm of the amide-containing compound is added to the medium.

21. The method of any one of claims 1 to 3, wherein the medium comprises from about 0.5% to about 5% by weight of the amide-containing compound.

22. The method of any one of claims 1 to 3, wherein the composition further comprises a polymerization inhibitor and / or a dispersant.

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