Compositions and methods for reducing polymer fouling and agglomeration in acrylate / methacrylate processes

Abstract

The present invention generally relates to a method for reducing polymer agglomeration or fouling, and its use in processes for the preparation of acrylic acid, an acrylate, methacrylic acid, or a methacrylate. According to the present invention, an antifoulant composition is applied to processes for the preparation of an acrylate, methacrylic acid, or a methacrylate to prevent polymeric foulant precursors from agglomerating or to dissolve existing polymeric agglomerates or foulants so as to reduce polymer agglomeration or fouling in the process or storage equipment. The antifoulant composition comprises a compound of : Formulae 1, 2, 3, or 4 having the structure corresponding to: (1); (2); (3); or (4) herein R1 is independently hydrogen, C1-C30 alkyl, C1-C30 alkenyl, aryl, alkaryl, or aralkyl; R2 and R3 are independently hydrogen, C1-C10 alkyl, aryl, or alkaryl; R4 and R5 are independently hydrogen or methyl; R6 is independently hydrogen or alkyl; R7 is independently alkyl, substituted alkyl, aryl, or substituted aryl; R8 and R9 are independently hydrogen, alkyl, or aryl; A1 is independently –O‑, ‑N(R8)‑, or –N(R8)C(O)‑; A2 is independently –OH, ‑N(R8)(R9), or –N(R8)C(O)R9; n is an integer from 1 to 6; o is an integer from 1 to 4; and p is an integer from 1 to 50.

Description

PATENT COMPOSITIONS AND METHODS FOR REDUCING POLYMER FOULING AND AGGLOMERATION IN ACRYLATE / METHACRYLATE PROCESSES FIELD OF THE INVENTION

[0001] The present invention generally relates to a method for reducing polymerfouling or agglomeration using an antifoulant composition, and its use in acrylic acid, an acrylate, methacrylic acid, or a methacrylate process. According to the present invention, the antifoulant composition is contacted with the substrate in acrylic acid, an acrylate, methacrylic acid, or a methacrylate process to prevent polymeric foulant precursors from agglomerating or to dissolve existing polymeric agglomerates and / or foulants to reduce polymer agglomeration or fouling in the process or storage equipment. BACKGROUND OF THE INVENTION

[0002] In the acetone cyanohydrin-methyl methacrylate (ACH-MMA) process,acetone cyanohydrin is added to an excess of sulfuric acid (1.4–1.8 mol / mol ACH), which acts as both reactant and solvent. The reaction between ACH and sulfuric acid produces - sulfatoisobutyramide, which then undergoes an elimination reaction under the heated process conditions to give methacrylamide sulfate.hydrolysis / esterification of the methacrylamide sulfate to a mixture of methyl methacrylate (MMA) and methylacrylic acid (MAA).PATENT

[0004] In one scheme, the methacrylamide sulfate is reacted with aqueous methanolin a continuous reactor or a series of reactors at temperatures of from 100°C to 150°C.

[0005] In the industrial process for the manufacture of methyl methacrylate (MMA),an aqueous sulfuric acid waste stream (spent acid) is produced. This spent acid stream is concentrated with sulfuric acid (H2S04), ammonium bisulfate (NH4.HSO4) and residual organic components. The organic components generally comprise a high proportion of residues and tars and smaller quantities of lighter organic compounds.

[0006] Due to the highly contaminated nature of MMA spent acid, the currentindustrial treatment method available for acid recovery and concentration is that involving regeneration. In this process, the spent acid is decomposed in a brick-lined furnace at about 1000°C. At this temperature, the organic components in the spent acid are oxidized to carbon dioxide and water, the ammonium salts are converted to nitrogen and sulfur dioxide; and the sulfuric acid is reduced to sulfur dioxide. The sulfur dioxide gas stream produced in the regeneration process passes through heat recovery and gas cleaning processes before being converted to sulfuric acid in a conventional contact acid plant.

[0007] Polymerization of MMA, MAA, acrylic acid, methacrylamide or other vinylmonomers is undesirable and very common in the manufacturing processes for preparing acrylic acid, an acrylate, methacrylic acid, or a methacrylate monomer. In the MMA manufacturing process, polymers formed from MMA, MAA, and other vinyl monomers flow out of the process with the spent acid. Many of the polymers formed have a lower density than the spent acid, so they float in the aqueous acid and when they agglomerate, precipitate out of the spent acid, or deposit on the equipment, they can cause process operating problems.

[0008] Polymer formation, agglomeration, and fouling are generally a concern for theprocesses for handling acrylic acid, an acrylate, methacrylic acid, or a methacrylate monomer. A sulfuric acid-containing waste stream often carries the polymer. Reducing or preventing the operation problems and disposing of the waste stream are challenging and costly goals.

[0009] A method for removing these polymer agglomerates or deposits once theyform and for preventing agglomeration or deposition of the polymers before they are formed is a need for the process.PATENT SUMMARY OF THE INVENTION

[0010] One aspect of the disclosure is a method of dispersing or dissolving an organicfoulant in a process fluid in contact with processing equipment for the preparation of acrylic acid, an acrylate, methacrylic acid, or a methacrylate monomer comprising contacting the foulant with an effective amount of an antifoulant composition comprising a compound of Formula 1, 2, 3, or 4 or a mixture thereof, the compound of Formula 1, 2, 3, or 4 having the structure corresponding to: oralkaryl, or aralkyl; R2 and R3 are independently hydrogen, C1-C10 alkyl, aryl, or alkaryl; R4 and R5 are independently hydrogen or methyl or benzyl; R6 is independently hydrogen or alkyl; R7 isPATENT independently alkyl, substituted alkyl, aryl, or substituted aryl; R8and R9are independently hydrogen, alkyl, -(CH2CH(R10)-O-)p, or aryl; R10 is hydrogen, methyl, or benzyl; A1 is independently –O-, -N(R8)-, or –N(R8)C(O)-; A2is independently –OH, -N(R8)(R9), or -N(R8)C(O)R9; n is an integer from 1 to 6; o is an integer from 1 to 4; and p is an integer from 1 to 50.

[0011] The methods disclosed herein have the processing equipment be forpreparation of methacrylic acid or methyl methacrylate.

[0012] Methods described herein have the processing equipment for preparation ofmethacrylic acid or methyl methacrylate adapted to the acetone cyanohydrin process.

[0013] The methods described herein have the process fluid comprise sulfuric acid, anammonium salt of sulfuric acid, or a combination thereof.

[0014] Methods disclosed herein have the process fluid comprise acrylic acid, anacrylate, methacrylic acid, a methacrylate, or a combination thereof.

[0015] Further, the methods of this disclosure have the process fluid comprisemethacrylic acid, methyl methacrylate, or a combination thereof.

[0016] The methods have the organic foulant comprise an oligomer or a polymer ofacrylic acid, methacrylic acid, an acrylate, a methacrylate, a methacrylamide, or a combination thereof.

[0017] Methods of dispersing or dissolving an organic foulant in a process fluid havethe organic foulant comprise an oligomer or a polymer of methacrylic acid, methyl methacrylate, methacrylamide, or a combination thereof.

[0018] Yet other methods have the antifoulant composition comprise (i) a compoundof Formula 1 and a compound of Formula 2, (ii) a compound of Formula 1 and a compound of Formula 3, (iii) a compound of Formula 1 and a compound of Formula 4, (iv) a compound of Formula 2 and a compound of Formula 3, (v) a compound of Formula 2 and a compound of Formula 4, (vi) a compound of Formula 3 and a compound of Formula 4, (vii) a compound of Formula 1, a compound of Formula 2, and a compound of Formula 3, (viii) a compound of Formula 1, a compound of Formula 2, and a compound of Formula 4, (ix) a compound of Formula 1, a compound of Formula 3, and a compound of Formula 4, and (x) a compound of Formula 1, a compound of Formula 2, a compound of Formula 3, and a compound of Formula 4.

[0019] Methods have the antifoulant composition comprise a compound of Formula 1PATENT .

[0020] The a compound ofFormula 1 have R1 hydrogen or C1-C3alkyl; R4and R5are independently hydrogen or methyl; R6is independently hydrogen or C1-C3 alkyl; R8 and R9 are independently hydrogen, alkyl, -(CH2CH(R10)-O-)p or aryl; R10is hydrogen, methyl, or benzyl; A1is independently –O- or -N(R8)-; n is an integer from 1 to 4; o is an integer from 1 to 3; and p is an integer from 1 to 30.

[0021] The methods can also have the compound of Formula 1 have a structure ofFormula 1A: .1A have R1 is C10-C30 alkyl orC10-C30 alkenyl; R2, R3, R4, R5, R6, R8, and R9 are independently hydrogen or methyl; A1 is independently –O- or -N(R8)-; n is an integer of 1 or 2; and p is an integer from 1 to 30.

[0023] The compounds having a structure of Formula 1A also have R1 is C16-C24alkyl or C16-C24alkenyl; R2, R3, R4, R5, R6, R8, and R9are hydrogen; A1is independently –O- or -N(R8)-; n is an integer of 2; and p is an integer from 6 to 24.

[0024] Further the methods can use an antifoulant composition comprising acompound of Formula 2PATENT . of Formula 2 has R1 is C1-C30 alkyl or C1-C30hydrogen or C1-C3alkyl; R4is hydrogen or methyl; R7 is alkyl, substituted alkyl, aryl, or substituted aryl; A2 is independently –OH, -N(R8)(R9), or –N(R8)C(O)R9; and n is an integer from 1 to 3.

[0026] The compound having a structure of Formula 2 also has R1 is C10-C30 alkyl orC10-C30 alkenyl; R2, R3, R4, R8 and R9 are independently hydrogen or methyl; R7 is C1-C6 alkyl or phenyl; A2 is independently –OH, -N(R8)(R9), or –N(R8)C(O)R9; and n is an integer of 2 or 3.

[0027] Also, the compound having a structure of Formula 2 has R1 is C16-C24 alkyl orC16-C24 alkenyl; R2, R3, R4, R8 and R9 are hydrogen; R7 is C1-C3 alkyl or phenyl; A2 is independently –OH, -N(R8)(R9), or –N(R8)C(O)R9; and n is an integer of 2.

[0028] Also, the methods of dispersing or dissolving an organic foulant in a processfluid use the antifoulant composition comprises a compound of Formula 3 .R1 is C1-C30 alkyl orC1-C30alkenyl; R2, R3, R6, R8and R9are independently hydrogen or C1-C3alkyl; R4and R5are independently hydrogen or methyl; A1 is independently –O-, -N(R8)-, or –N(R8)C(O)-; n and o are an integer from 1 to 3; and p is an integer from 8 to 40.

[0030] The compounds having the structure of Formula 3 have R1 is C16-C24 alkyl orC16-C24alkenyl; R2, R3, R4and R5are hydrogen; R6, R8and R9are independently hydrogen or methyl; A1 is independently –O-, -N(R8)-, or –N(R8)C(O)-; n and o are an integer or 2 or 3; and p is an integer from 10 to 30.PATENT

[0031] Additionally, the methods can use the antifoulant composition comprising acompound of Formula 4 . is C1-C30 alkyl or C1-C30 alkenyl; R2, R3,R8, R4is hydrogen or methyl; R7is alkyl, substituted alkyl, aryl, or substituted aryl; A2 is independently –OH, -N(R8)(R9), or – N(R8)C(O)R9; and n is an integer from 1 to 3.

[0033] The compound of Formula 4 can also have R1 is C10-C30 alkyl or C10-C30alkenyl; R2, R3, R4, R8, and R9are independently hydrogen or methyl; R7is C1-C6alkyl or phenyl; A2 is independently –OH, -N(R8)(R9), or –N(R8)C(O)R9; and n is an integer of 2 or 3.

[0034] Further, the compound of Formula 4 has R1 is C16-C24 alkyl or C16-C24alkenyl; R2, R3, R4, R8, and R9are hydrogen; R7is C1-C3alkyl or phenyl; A2is independently –OH, -N(R8)(R9), or –N(R8)C(O)R9; and n is an integer of 2.

[0035] The methods can additionally use the antifoulant composition furthercomprising a solvent.

[0036] The solvent of the antifoulant composition comprises water, an alcohol, anester, an ether, a hydrocarbon, or a combination thereof.

[0037] When the solvent of the antifoulant composition is an organic solvent, theorganic solvent comprises water, methanol, ethanol, propanol, dimethyl ether, diethyl ether, or a combination thereof.

[0038] The methods can have use antifoulant composition that have the concentrationof the compound of Formula 1, 2, 3, 4, or a combination thereof in the fluid is from about 1 ppm by weight to about 5000 ppm by weight based on the total weight of the compound of Formula 1, 2, 3, or 4 and solvent. Preferably, the concentration of the compound of Formula 1, 2, 3, 4, or a combination thereof is from about 500 ppm to about 2000ppm.

[0039] In the methods described herein, the antifoulant composition can be used todisperse or prevent the organic foulant from agglomeration, precipitation, or deposition.PATENT

[0040] In the methods of dispersing or dissolving an organic foulant in a process fluidthe antifoulant composition is added to the process fluid continuously or intermittently.

[0041] Methods described herein can use an antifoulant composition that furthercomprises a chemical additive of a second solvent, a dispersant, a polymerization inhibitor, or a combination thereof.

[0042] Another aspect of the disclosure is a composition comprising aqueous sulfuricacid, an antifoulant composition, and a polymer of acrylic acid, an acrylate, methacrylic acid, a methacrylate, a methacrylamide, or a combination thereof, wherein the antifoulant composition comprises a compound of Formulae 1, 2, 3, or 4, or a combination thereof having the structures corresponding to: orPATENT wherein R1is independently hydrogen, C1-C30alkyl, C1-C30alkenyl, aryl, alkaryl, or aralkyl; R2 and R3 are independently hydrogen, C1-C10 alkyl, aryl, or alkaryl; R4 and R5 are independently hydrogen or methyl; R6is independently hydrogen or alkyl; R7is independently alkyl, substituted alkyl, aryl, or substituted aryl; R8and R9are independently hydrogen, alkyl, or aryl; A1 is independently –O-, -N(R8)-, or –N(R8)C(O)-; A2 is independently –OH, -N(R8)(R9), or –N(R8)C(O)R9; n is an integer from 1 to 6; o is an integer from 1 to 4; and p is an integer from 1 to 50.

[0043] Other objects and features will be in part apparent and in part pointed outhereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 is a schematic of the equipment used in a typical methyl methacrylateprocess.

[0045] Figure 2 is picture of test tubes showing a floating methyl methacrylate(MMA) foulant in a spent acid process stream.

[0046] Figure 3 is series of pictures showing test tubes containing a MMA foulant ina spent acid process stream and treated with various antifoulant compositions (e.g., Control is hydroxyethyl imidazoline; A is ethoxylated hydroxyethyl imidazoline; B is quaternary ammonium salt of hydroxyethyl imidazoline; and C is quaternary ammonium salt of aminoethyl imidazoline) shown at 15 minutes and 2 hours after addition of antifoulant composition.

[0047] Corresponding reference characters indicate corresponding parts throughoutthe drawings. DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0048] The present invention is directed to a method of dispersing or dissolvingpolymer foulants produced in the process for preparing acrylic acid, an acrylate, methacrylic acid, or a methacrylate monomer. Polymers of acrylic acid, an acrylate, methacrylic acid, a methacrylate, a methacrylamide, or other vinyl monomers form as side products. The polymer can become insoluble and then precipitate out of a process stream. The polymer precipitate could deposit on process equipment surface as foulant or agglomerate into large pieces of polymer which can precipitate and separate out of process fluid and adversely affect process operation. The method of the invention disperses or dissolves the insoluble polymerPATENT agglomerate in a liquid process stream. In some cases, there are significant advantages for the antifoulant compositions to comprise water-soluble compounds. For example, antifoulant compositions comprising the compounds having the structures of Formula 1, 2, 3, 4, or a combination thereof have been found to be effective for dispersing polymer agglomerates in a spent acid stream of the methyl methacrylate process. Thus, one advantageous aspect of the method is using antifoulant compositions described herein to reduce or prevent polymer agglomeration or to dissolve an existing polymer agglomerate into a free-flowing liquid and thereby reduce the polymer deposition or fouling of the process equipment.

[0049] One aspect of the disclosure is a method of dispersing or dissolving an organicfoulant in a process fluid in contact with processing equipment for the preparation of acrylic acid, an acrylate, methacrylic acid, or a methacrylate monomer comprising contacting the foulant with an effective amount of an antifoulant composition comprising a compound of Formula 1, 2, 3, or 4 or a mixture thereof, the compound of Formula 1, 2, 3, or 4 having the structure corresponding to: orPATENT C1-C30 alkenyl, aryl, alkaryl, or aralkyl;R2and aryl, or alkaryl; R4and R5are independently hydrogen or methyl or benzyl; R6 is independently hydrogen or alkyl; R7 is independently alkyl, substituted alkyl, aryl, or substituted aryl; R8and R9are independently hydrogen, alkyl, -(CH2CH(R10)-O-)p, or aryl; R10 is hydrogen, methyl, or phenyl; A1 is independently –O-, -N(R8)-, or –N(R8)C(O)-; A2is independently –OH, -N(R8)(R9), or -N(R8)C(O)R9; n is an integer from 1 to 6; o is an integer from 1 to 4; and p is an integer from 1 to 50.

[0050] The methods disclosed herein have the processing equipment preferably be forpreparation of methacrylic acid or methyl methacrylate.

[0051] Methods described herein more preferably have the processing equipment forpreparation of methacrylic acid or methyl methacrylate adapted to the acetone cyanohydrin process.

[0052] The methods described herein preferably have the process fluid comprisesulfuric acid, an ammonium salt of sulfuric acid, or a combination thereof.

[0053] Methods disclosed herein more preferably have the process fluid compriseacrylic acid, an acrylate, methacrylic acid, a methacrylate, or a combination thereof.

[0054] Further, the methods of this disclosure most preferably have the process fluidcomprise methacrylic acid, methyl methacrylate, or a combination thereof.

[0055] The methods preferably have the organic foulant comprise an oligomer or apolymer of acrylic acid, methacrylic acid, an acrylate, a methacrylate, a methacrylamide, or a combination thereof.

[0056] Methods of dispersing or dissolving an organic foulant in a process fluid morepreferably have the organic foulant comprise an oligomer or a polymer of methacrylic acid, methyl methacrylate, methacrylamide, or a combination thereof.

[0057] Yet other methods have the antifoulant composition comprise (i) a compoundof Formula 1 and a compound of Formula 2, (ii) a compound of Formula 1 and a compoundPATENT of Formula 3, (iii) a compound of Formula 1 and a compound of Formula 4, (iv) a compound of Formula 2 and a compound of Formula 3, (v) a compound of Formula 2 and a compound of Formula 4, (vi) a compound of Formula 3 and a compound of Formula 4, (vii) a compound of Formula 1, a compound of Formula 2, and a compound of Formula 3, (viii) a compound of Formula 1, a compound of Formula 2, and a compound of Formula 4, (ix) a compound of Formula 1, a compound of Formula 3, and a compound of Formula 4, and (x) a compound of Formula 1, a compound of Formula 2, a compound of Formula 3, and a compound of Formula 4.

[0058] Methods have the antifoulant composition comprise a compound of Formula 1.

[0059] Thea compound ofFormula 1 have R1 is C1-C30 alkyl or C1-C30 alkenyl; preferably, R1 is C10-C30 alkyl or C10- C30alkenyl; more preferably, R1is C11-C30alkyl or C13-C30alkenyl; even more preferably, R1is C15-C30 alkyl or C17-C30 alkenyl; even more preferably, R1 is C15-C23 alkyl or C15-C23 alkenyl; even more preferably, R1is C15-C21alkyl or C15-C21alkenyl; most preferably, R1is C15-C19 alkyl or C15-C19 alkenyl.

[0060] The compounds having the structure of Formula 1 also preferably have R2 andR3 are independently hydrogen or C1-C3 alkyl; more preferably, R2 and R3 are independently hydrogen or methyl; most preferably, R2 and R3 are hydrogen.

[0061] The compounds of Formula 1 preferably have R4 and R5 are independentlyhydrogen or methyl.

[0062] The compounds of Formula 1 preferably have R6 is independently hydrogen orC1-C3 alkyl; or more preferably, R6 is independently hydrogen or methyl.

[0063] The compounds of Formula 1 preferably have R8 is hydrogen, alkyl, or aryl;more preferably, R8 is hydrogen, C1-C6 alkyl, or phenyl.

[0064] The compounds of Formula 1 preferably have A1 is independently –O- or-N(R8)-; most preferably, A1 is -O-; or more preferably, A1 is -N(R8)-.PATENT

[0065] The compounds of Formula 1 preferably have n is an integer from 1 to 4; morepreferably, n is an integer of 2 or 3; or most preferably, n is an integer of 2.

[0066] The compounds of Formula 1 preferably have o is an integer from 1 to 3; morepreferably, o is an integer of 2 or 3; or most preferably, o is an integer of 2.

[0067] The compounds of Formula 1 preferably have p is an integer from 1 to 30;more preferably, p is an integer from 4 to 30; more preferably, p is an integer from 6 to 30; more preferably, p is an integer from 8 to 30; preferably, p is an integer from 1 to 24; more preferably, p is an integer from 4 to 24; more preferably, p is an integer from 6 to 24; more preferably, p is an integer from 8 to 24; preferably, p is an integer from 1 to 20; more preferably, p is an integer from 4 to 20; more preferably, p is an integer from 6 to 20; more preferably, p is an integer from 8 to 20; preferably, p is an integer from 1 to 16; more preferably, p is an integer from 4 to 16; more preferably, p is an integer from 6 to 16; or most preferably, p is an integer from 8 to 16.

[0068] The methods can also have the compound of Formula 1 have a structure ofFormula 1A: .1A have R1 is C10-C30 alkyl orC10-C30 alkenyl; R2, R3, R4, R5, R6, R8, and R9 are independently hydrogen or methyl; A1 is independently –O- or -N(R8)-; n is an integer of 1 or 2; and p is an integer from 1 to 30.

[0070] The compounds having a structure of Formula 1A also have R1 is C16-C24alkyl or C16-C24alkenyl; R2, R3, R4, R5, R6, R8, and R9are hydrogen; A1is independently –O- or -N(R8)-; n is an integer of 2; and p is an integer from 6 to 24.

[0071] In addition, the definitions of R1, R2, R3, R4, R5, R6, R8, A1, n, o, and p inconnection with compounds of Formula 1 are also applicable to compounds of Formula 1A.

[0072] Further the methods can use an antifoulant composition comprising acompound of Formula 2PATENT . of Formula 2 has R1 is C1-C30 alkyl or C1-C30hydrogen or C1-C3alkyl; R4is hydrogen or methyl; R7 is alkyl, substituted alkyl, aryl, or substituted aryl; A2 is independently –OH, -N(R8)(R9), or –N(R8)C(O)R9; and n is an integer from 1 to 3.

[0074] The substituents for R7 substituted alkyl and substituted aryl are preferablycarboxyl or hydroxyl; more preferably, the substituent for substituted alkyl is carboxyl.

[0075] The compound having a structure of Formula 2 also has R1 is C10-C30 alkyl orC10-C30 alkenyl; R2, R3, R4, R8 and R9 are independently hydrogen or methyl; R7 is C1-C6 alkyl or phenyl; A2is independently –OH, -N(R8)(R9), or –N(R8)C(O)R9; and n is an integer of 2 or 3.

[0076] Also, the compound having a structure of Formula 2 has R1 is C16-C24 alkyl orC16-C24 alkenyl; R2, R3, R4, R8 and R9 are hydrogen; R7 is C1-C3 alkyl or phenyl; A2 is independently –OH, -N(R8)(R9), or –N(R8)C(O)R9; and n is an integer of 2.

[0077] The methods having the antifoulant composition comprise a compound ofFormula 2 preferably have R1is C1-C30alkyl or C1-C30alkenyl; more preferably, R1is C10- C30 alkyl or C10-C30 alkenyl; more preferably, R1 is C11-C30 alkyl or C13-C30 alkenyl; more preferably, R1 is C15-C30 alkyl or C17-C30 alkenyl; more preferably, R1 is C15-C23 alkyl or C15- C23 alkenyl; more preferably, R1 is C15-C21 alkyl or C15-C21 alkenyl; or most preferably, R1 is C15-C19 alkyl or C15-C19 alkenyl.

[0078] The compounds having the structure of Formula 2 preferably also have R2 andR3 are independently hydrogen or C1-C3 alkyl; more preferably, R2 and R3 are independently hydrogen or methyl; or most preferably, R2and R3are hydrogen.

[0079] The compounds of Formula 2 preferably have R4 is independently hydrogen ormethyl.

[0080] The compounds of Formula 2 preferably have R8 is hydrogen, alkyl, or aryl;more preferably, R8is hydrogen, C1-C6alkyl, or phenyl; more preferably, R8is hydrogen,PATENT methyl, ethyl, propyl, or phenyl; even more preferably, R8is hydrogen, methyl, or phenyl; or most preferably, R8 is hydrogen.

[0081] The compounds of Formula 2 preferably have A1 is independently –O- or-N(R8)-; most preferably, A1is -O-; or more preferably, A1is -N(R8)-.

[0082] The compounds of Formula 2 preferably have n is an integer from 1 to 4;preferably, n is an integer of 2 or 3; or more preferably, or most preferably, n is an integer of 2.

[0083] The compounds of Formula 2 have p is an integer from 1 to 30; preferably, pis an integer from 4 to 30; more preferably, p is an integer from 6 to 30; more preferably, p is an integer from 8 to 30; preferably, p is an integer from 1 to 24; more preferably, p is an integer from 4 to 24; more preferably, p is an integer from 6 to 24; more preferably, p is an integer from 8 to 24; preferably, p is an integer from 1 to 20; more preferably, p is an integer from 4 to 20; more preferably, p is an integer from 6 to 20; more preferably, p is an integer from 8 to 20; preferably, p is an integer from 1 to 16; more preferably, p is an integer from 4 to 16; more preferably, p is an integer from 6 to 16; or most preferably, p is an integer from 8 to 16.

[0084] Also, the methods of dispersing or dissolving an organic foulant in a processfluid use the antifoulant composition comprises a compound of Formula 3 .R1 is C1-C30 alkyl orC1-C30alkenyl; R2, R3, R6, R8and R9are independently hydrogen or C1-C3alkyl; R4and R5are independently hydrogen or methyl; A1is independently –O-, -N(R8)-, or –N(R8)C(O)-; n and o are an integer from 1 to 3; and p is an integer from 8 to 40.

[0086] The compounds having the structure of Formula 3 have R1 is C16-C24 alkyl orC16-C24 alkenyl; R2, R3, R4 and R5 are hydrogen; R6, R8 and R9 are independently hydrogen or methyl; A1is independently –O-, -N(R8)-, or –N(R8)C(O)-; n and o are an integer or 2 or 3; and p is an integer from 10 to 30.

[0087] Additionally, the methods can use the antifoulant composition comprising acompound of Formula 4PATENT . is C1-C30 alkyl or C1-C30 alkenyl; R2, R3,R8, R4is hydrogen or methyl; R7is alkyl, substituted alkyl, aryl, or substituted aryl; A2 is independently –OH, -N(R8)(R9), or – N(R8)C(O)R9; and n is an integer from 1 to 3.

[0089] The substituents for R7 substituted alkyl and substituted aryl are preferablycarboxyl or hydroxyl; more preferably, the substituent for substituted alkyl is carboxyl.

[0090] The compound of Formula 4 can also have R1 is C10-C30 alkyl or C10-C30alkenyl; R2, R3, R4, R8, and R9are independently hydrogen or methyl; R7is C1-C6alkyl or phenyl; A2 is independently –OH, -N(R8)(R9), or –N(R8)C(O)R9; and n is an integer of 2 or 3.

[0091] Further, the compound of Formula 4 has R1 is C16-C24 alkyl or C16-C24alkenyl; R2, R3, R4, R8, and R9are hydrogen; R7is C1-C3alkyl or phenyl; A2is independently –OH, -N(R8)(R9), or –N(R8)C(O)R9; and n is an integer of 2.

[0092] The methods can additionally use the antifoulant composition furthercomprising a solvent.

[0093] The solvent of the antifoulant composition comprises water, an alcohol, anester, an ether, a hydrocarbon, or a combination thereof.

[0094] When the solvent of the antifoulant composition is an organic solvent, theorganic solvent comprises water, methanol, ethanol, propanol, dimethyl ether, diethyl ether, or a combination thereof.

[0095] The methods can have use antifoulant composition that have the concentrationof the compound of Formula 1, 2, 3, 4, or a combination thereof in the fluid is from about 1 ppm by weight to about 5000 ppm by weight based on the total weight of the compound of Formula 1, 2, 3, or 4 and solvent. Preferably, the concentration of the compound of Formula 1, 2, 3, 4, or a combination thereof is from about 500 ppm to about 2000ppm.

[0096] In the methods described herein, the antifoulant composition can be used todisperse or prevent the organic foulant from agglomeration, precipitation, or deposition.PATENT

[0097] In the methods of dispersing or dissolving an organic foulant in a process fluidthe antifoulant composition is added to the process fluid continuously or intermittently.

[0098] Methods described herein can use an antifoulant composition that furthercomprises a chemical additive of a second solvent, a dispersant, a polymerization inhibitor, or a combination thereof.

[0099] Another aspect of the disclosure is a composition comprising aqueous sulfuricacid, an antifoulant composition, and a polymer of acrylic acid, an acrylate, methacrylic acid, a methacrylate, a methacrylamide, or a combination thereof, wherein the antifoulant composition comprises a compound of Formulae 1, 2, 3, or 4, or a combination thereof having the structures corresponding to: orPATENT wherein R1is independently hydrogen, C1-C30alkyl, C1-C30alkenyl, aryl, alkaryl, or aralkyl; R2 and R3 are independently hydrogen, C1-C10 alkyl, aryl, or alkaryl; R4 and R5 are independently hydrogen or methyl; R6is independently hydrogen or alkyl; R7is independently alkyl, substituted alkyl, aryl, or substituted aryl; R8and R9are independently hydrogen, alkyl, or aryl; A1 is independently –O-, -N(R8)-, or –N(R8)C(O)-; A2 is independently –OH, -N(R8)(R9), or –N(R8)C(O)R9; n is an integer from 1 to 6; o is an integer from 1 to 4; and p is an integer from 1 to 50.

[0100] A further aspect of the disclosure is an antifoulant composition comprisingtwo or more of a compound of Formula 1, 2, 3, or 4 or a mixture thereof, the compound of Formula 1, 2, 3, or 4 having the structure corresponding to: orPATENT wherein R1is independently hydrogen, C1-C30alkyl, C1-C30alkenyl, aryl, alkaryl, or aralkyl; R2 and R3 are independently hydrogen, C1-C10 alkyl, aryl, or alkaryl; R4 and R5 are independently hydrogen or methyl or benzyl; R6is independently hydrogen or alkyl; R7is independently alkyl, substituted alkyl, aryl, or substituted aryl; R8and R9are independently hydrogen, alkyl, or aryl; A1 is independently –O-, -N(R8)-, or –N(R8)C(O)-; A2 is independently –OH, -N(R8)(R9), or -N(R8)C(O)R9; n is an integer from 1 to 6; o is an integer from 1 to 4; and p is an integer from 1 to 50.

[0101] The antifoulant composition described herein comprises (i) a compound ofFormula 1 and a compound of Formula 2, (ii) a compound of Formula 1 and a compound of Formula 3, (iii) a compound of Formula 1 and a compound of Formula 4, (iv) a compound of Formula 2 and a compound of Formula 3, (v) a compound of Formula 2 and a compound of Formula 4, (vi) a compound of Formula 3 and a compound of Formula 4, (vii) a compound of Formula 1, a compound of Formula 2, and a compound of Formula 3, (viii) a compound of Formula 1, a compound of Formula 2, and a compound of Formula 4, (ix) a compound of Formula 1, a compound of Formula 3, and a compound of Formula 4, and (x) a compound of Formula 1, a compound of Formula 2, a compound of Formula 3, and a compound of Formula 4.

[0102] The compounds having the structure of Formula 1, 2, 3, or 4 with or withoutthe preferred substituents described above can be components of the antifoulant compositions described herein.

[0103] Imidazolines can be made by reacting a fatty acid with an amine. In additionto an imidazoline, amides are also produced as a byproduct. The derivatives of these imidazolines include its hydrolysate, quaternary ammonium salt, epoxidation, and the like. Hydrolysis reactions of the imidazolines yield amides and diamides, which can be produced either in the presence of catalyst or without the presence of catalyst. The quaternary ammonium salts of these imidazolines is made by reacting haloacetic acid with the formed imidazolines. Epoxidation of the imidazolines is reacting ethylene oxide with the imidazolines.

[0104] Figure 1 shows the reactor 10, the spent acid stream 30, the spent acid storagetank 50, the spent acid recovery unit 70, and the several places that the organic solvent could be added to the process. In particular, the organic solvent can be added the spent acid storage tank circulation stream 60. Additionally, the organic solvent can be added to the spent acid reactor bottoms stream 30 at injection point 40 in order to treat the stream before it reachesPATENT the acid regeneration unit or the spent acid storage tank. Finally, the organic solvent can be added to the reactor inlet 20 or if there is more than one reactor in the system, in between the reactors in order to prevent the agglomeration or deposition of the polymer in the processing system.

[0105] The organic solvent can be added to the processing system continuously orintermittently in order to provide a spent acid stream that does not contain a solid polymer that precipitates out of the process fluid or deposits on the equipment. The organic solvent can be added into one or more of the streams in order to maintain a flowing polymer stream within the spent acid stream.

[0106] Unless otherwise indicated herein, an “acrylate” is a salt or ester of acrylicacid.

[0107] Unless otherwise indicated herein, a “organic foulant” comprises an organiccompound that forms in the process or is an impurity of a process material that is insoluble in the process stream where it is present and / or polymerizes or aggregates in the system to form particles that become insoluble in the process stream.

[0108] Unless otherwise indicated herein, a methacrylate” is a salt or ester ofmethacrylic acid.

[0109] The term “alkyl,” as used herein, refers to a linear or branched hydrocarbonradical, preferably having 1 to 32 carbon atoms (i.e., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 39, 30, 31, or 32 carbons). Alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, secondary-butyl, and tertiary-butyl. Alkyl groups may be unsubstituted or substituted by one or more suitable substituents, as defined above.

[0110] The term “alkenyl,” as used herein, refers to a straight or branchedhydrocarbon radical, preferably having 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 39, 30, 31, or 32 carbons, and having one or more carbon-carbon double bonds. Alkenyl groups include, but are not limited to, ethenyl, 1- propenyl, 2-propenyl (allyl), iso-propenyl, 2-methyl-1-propenyl, 1-butenyl, and 2-butenyl. Alkenyl groups may be unsubstituted or substituted by one or more suitable substituents, as defined above.

[0111] The term “alkoxy,” as used herein, refers to an alkyl group, as defined herein,appended to the parent molecular moiety through an oxygen atom.PATENT

[0112] The term “aryl,” as used herein, means monocyclic, bicyclic, or tricyclicaromatic radicals such as phenyl, naphthyl, tetrahydronaphthyl, indanyl and the like; optionally substituted by one or more suitable substituents, preferably 1 to 5 suitable substituents, as defined above.

[0113] The term “aralkyl” as used herein denotes an aryl group as defined aboveattached to an alkyl group as defined above, wherein the alkyl group of the aralkyl group is attached to the larger compound.

[0114] The term “alkaryl” as used herein denotes an alkyl group as defined aboveattached to an aryl group as defined above, wherein the aryl group of the alkaryl group is attached to the larger compound.

[0115] The term “cycloalkyl,” as used herein, refers to a mono, bicyclic or tricycliccarbocyclic radical (e.g., cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclopentenyl, cyclohexenyl, bicyclo[2.2.1]heptanyl, bicyclo[3.2.1]octanyl and bicyclo[5.2.0]nonanyl, etc.); optionally containing 1 or 2 double bonds. Cycloalkyl groups may be unsubstituted or substituted by one or more suitable substituents, preferably 1 to 5 suitable substituents, as defined above.

[0116] The term “halo” or “halogen,” as used herein, refers to a fluoro, chloro, bromoor iodo radical.

[0117] The term “heteroaryl,” as used herein, refers to a monocyclic, bicyclic, ortricyclic aromatic heterocyclic group containing one or more heteroatoms (e.g., 1 to 3 heteroatoms) selected from O, S and N in the ring(s). Heteroaryl groups include, but are not limited to, pyridyl, pyrazinyl, pyrimidinyl, pyridazinyl, thienyl, furyl, imidazolyl, pyrrolyl, oxazolyl (e.g., 1,3-oxazolyl, 1,2-oxazolyl), thiazolyl (e.g., 1,2-thiazolyl, 1,3-thiazolyl), pyrazolyl, tetrazolyl, triazolyl (e.g., 1,2,3-triazolyl, 1,2,4-triazolyl), oxadiazolyl (e.g., 1,2,3- oxadiazolyl), thiadiazolyl (e.g., 1,3,4-thiadiazolyl), quinolyl, isoquinolyl, benzothienyl, benzofuryl, and indolyl. Heteroaryl groups may be unsubstituted or substituted by one or more suitable substituents, preferably 1 to 5 suitable substituents, as defined above.

[0118] The term “heterocycle” or “heterocyclyl,” as used herein, refers to amonocyclic, bicyclic, or tricyclic group containing 1 to 4 heteroatoms selected from N, O, S(O)n, P(O)n, PRz, NH or NRz, wherein Rzis a suitable substituent. Heterocyclic groups optionally contain 1 or 2 double bonds. Heterocyclic groups include, but are not limited to, azetidinyl, tetrahydrofuranyl, imidazolidinyl, pyrrolidinyl, piperidinyl, piperazinyl, oxazolidinyl, thiazolidinyl, pyrazolidinyl, thiomorpholinyl, tetrahydrothiazinyl, tetrahydro-PATENT thiadiazinyl, morpholinyl, oxetanyl, tetrahydrodiazinyl, oxazinyl, oxathiazinyl, indolinyl, isoindolinyl, quinuclidinyl, chromanyl, isochromanyl, and benzoxazinyl. Examples of monocyclic saturated or partially saturated ring systems are tetrahydrofuran-2-yl, tetrahydrofuran-3-yl, imidazolidin-1-yl, imidazolidin-2-yl, imidazolidin-4-yl, pyrrolidin-1-yl, pyrrolidin-2-yl, pyrrolidin-3-yl, piperidin-1-yl, piperidin-2-yl, piperidin-3-yl, piperazin-1-yl, piperazin-2-yl, piperazin-3-yl, 1,3-oxazolidin-3-yl, isothiazolidine, 1,3-thiazolidin-3-yl, 1,2- pyrazolidin-2-yl, 1,3-pyrazolidin-1-yl, thiomorpholin-yl, 1,2-tetrahydrothiazin-2-yl, 1,3- tetrahydrothiazin-3-yl, tetrahydrothiadiazin-yl, morpholin-yl, 1,2-tetrahydrodiazin-2-yl, 1,3- tetrahydrodiazin-1-yl, 1,4-oxazin-2-yl, and 1,2,5-oxathiazin-4-yl. Heterocyclic groups may be unsubstituted or substituted by one or more suitable substituents, preferably 1 to 3 suitable substituents, as defined above.

[0119] The term “hydroxy,” as used herein, refers to an -OH group.

[0120] The term “suitable substituent,” as used herein, is intended to mean achemically acceptable functional group, preferably a moiety that does not negate the activity of the inventive compounds. 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, heterocylic groups, cycloalkyl groups, amino groups, alkyl - and dialkylamino groups, carbamoyl groups, alkylcarbonyl groups, alkoxycarbonyl groups, alkylaminocarbonyl groups, dialkylamino carbonyl groups, arylcarbonyl groups, aryloxycarbonyl groups, alkylsulfonyl groups, and arylsulfonyl groups. Those skilled in the art will appreciate that many substituents can be substituted by additional substituents.

[0121] As used herein, approximating language may be applied to modify anyquantitative representation that may vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as "about" and "substantially," may not be limited to the precise value specified, in some cases. In at least some instances, the approximating language may correspond to the precision of an instrument for measuring the value. For example, “about” is meant to encompass variations of ±10%, more preferably ±5%, even more preferably ±1% from the specified value. The modifier "about" should also be considered as disclosing the range defined by the absolute values ofPATENT the two endpoints. For example, the expression "from about 2 to about 4" also discloses the range "from 2 to 4."

[0122] Having described the invention in detail, it will be apparent that modificationsand variations are possible without departing from the scope of the invention defined in the appended claims. EXAMPLES

[0123] The following non-limiting examples are provided to further illustrate thepresent invention. Example 1: Synthesis of imidazolines

[0124] The imidazoline is prepared by reacting fatty acid with an amine material. Thefatty acid can be either from natural material such as tall oil, oleic acid, colza oil, olive oil, and the like; or animal oil, or a mixture of them.

[0125] The epoxidation products are the product from imidazoline with ethyleneoxide. The quaternary-ammonium-salts are the product of imidazoline with haloacetic acid, sulfonic acid, benzyl halide etc. The hydrolysate products are made by the hydrolysis reaction of the below imidazolines in the presence of water.

[0126] The said antifoulant can be selected from one or more of the above structures.A mixture can be made by the physical blending the final materials or reacting with fatty acid mixture and polyene polyamines.

[0127] Imidazoline is made by reacting a fatty acid with amines as stated previously,beside imidazoline, the amide structure also be produced as a byproduct. The derivatives of imidazoline include its hydrolysate, quaternary ammonium salt, epoxidation, etc. Hydrolysis reaction of the imidazoline yield amides and diamides which can be produced either in the presence of catalyst or without catalyst. The quaternary ammonium salt of imidazoline is made by reacting haloacetic acid with the formed imidazoline. Epoxidation of imidazoline is reacting ethylene oxide with imidazoline. So, the dispersant composition in this ROI can be a mixture of imidazoline and amide. Example 2: Foulant dispersion tests

[0128] The performance of removing foulants was tested using a tube method. Theprocedure includes: (1) foulants from the spent acid recovery unit are dissolved in anPATENT appropriate solvent at a concentration of about 5 wt.% to form a foulant solution; (2) 500 µL of the foulant solution was added into about 20 mL spent acid stream that includes the antifoulant composition at the desired concentration; (4) the mixture was heated at 120 ºC after mixing for 30 to 90 minutes; and (5) the mixture was allowed to stand until reaching room temperature and the foulant layer was observed.

[0129] In the esterification units, polymers and byproducts are aggregated in the spentacid stream which composes with sulfuric acid, ammonia salt, water, and monomers to form the fouling issue. Without treatment, the foulant floated gradually on the spent acid stream as shown in Figure 2.

[0130] Three types of imidazolines were evaluated. Product A could be made by anepoxidation reaction between oleic acid hydroxyethyl imidazoline and ethylene oxide (epoxidized hydroxyethyl imidazoline fatty acid having approximately 10 ethylene oxide units). Product B could be made by reacting with aminoethylethanolamine, oleic acid, and dimethyl sulfate (sulfonic imidazoline quaternary ammonium salt prepared from aminoethylethanolamine, oleic acid, and dimethyl sulfate). Product C could be made by reacting with diethylenetriamine, oleic acid, and dimethyl sulfate (sulfonic imidazoline quaternary ammonium salt prepared from diethylenetriamine, oleic acid, and dimethyl sulfate). Meanwhile, an oil soluble hydroxyethyl imidazoline was used as control agent. As showed in Figure 3, the foulant was slowly precipitated and aggregated into big particle size in the spent acid stream without chemical treatment. Under the treatment of an oil-soluble imidazoline (control), the foulant quickly floated on the liquid surface, leaving less foulant residual in the spent acid after standing a long time, which prevented the blockage issue of the equipment.

[0131] Under the treatment of water-soluble imidazolines, the foulant particles kept afine size in spent acid without aggregation even after standing for 15 minutes which indicated the chemicals were capable of dispersing foulant particles. As the treatment time increases, most of the foulant particles accumulated on the liquid surface and the foulant layer height decreased in the presence of antifoulant composition A, B, and C as compared to the blank. Since the amount of foulant particles on the surfaces decreased, these results at two hours suggested there are still particles dispersing in the liquid with dispersant present at this point. Comparatively, the quaternary ammonium salt of imidazolines (B and C) showed a better performance with less foulant floating on the liquid surface. With the addition of dispersant, as the foulant dispersed I the stream for a longer time than the oil based imidazoline, thePATENT dispersed foulant had a smaller particle size and could move with the stream to the following units, like storage tank, furnace without causing a fouling problem. As a result, less foulant is left in such unit, a longer run length is achieved. Especially, faster liquid feed rate (higher operation load), less foulant resides in the units.

[0132] Comparing the oil-soluble imidazoline, this water soluble imidazoline is mucheasier to be handle on field, it can be diluted by water, alcohols, and monomers. Also, it is a more cost effective treatment program.

[0133] When introducing elements of the present invention or the preferredembodiments(s) thereof, the articles "a", "an", "the" and "said" are intended to mean that there are one or more of the elements. The terms "comprising", "including" and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements.

[0134] In view of the above, it will be seen that the several objects of the inventionare achieved and other advantageous results attained.

[0135] As various changes could be made in the above methods without departingfrom the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Claims

PATENT WHAT IS CLAIMED IS:

1. A method of dispersing or dissolving a organic foulant in a process fluid in contact with processing equipment for the preparation of acrylic acid, an acrylate, methacrylic acid, or a methacrylate monomer comprising contacting the foulant with an effective amount of an antifoulant composition comprising a compound of Formulae 1, 2, 3, or 4 having the structure corresponding to: oralkaryl, or aralkyl; R2 and R3 are independently hydrogen, C1-C10 alkyl, aryl, or alkaryl;PATENT R4and R5are independently hydrogen or methyl or benzyl; R6 is independently hydrogen or alkyl; R7is independently hydrogen, alkyl, substituted alkyl, aryl, or substituted aryl; R8and R9are independently hydrogen, alkyl, -(CH2CH(R10)-O-)p or aryl; R10 is hydrogen, methyl, or benzyl; A1is independently –O-, -N(R8)-, or –N(R8)C(O)-; A2 is independently –OH, -N(R8)(R9), or –N(R8)C(O)R9; n is an integer from 1 to 6; o is an integer from 1 to 4; and p is an integer from 1 to 50.

2. The method of claim 1, wherein the processing equipment is for preparation of methacrylic acid or methyl methacrylate.

3. The method of claim 2, wherein the processing equipment for preparation of methacrylic acid or methyl methacrylate is adapted to the acetone cyanohydrin process.

4. The method of any one of claims 1 to 3, wherein the process fluid comprises sulfuric acid, an ammonium salt of sulfuric acid, or a combination thereof.

5. The method of claim 4, wherein the process fluid comprises acrylic acid, an acrylate, methacrylic acid, a methacrylate, or a combination thereof.

6. The method of claim 5, wherein the process fluid comprises methacrylic acid, methyl methacrylate, or a combination thereof.

7. The method of any one of claims 1 to 6, wherein the organic foulant comprises an oligomer or a polymer of acrylic acid, methacrylic acid, an acrylate, a methacrylate, a methacrylamide, or a combination thereof.

8. The method of claim 7, wherein the organic foulant comprises an oligomer or a polymer of methacrylic acid, methyl methacrylate, methacrylamide, or a combination thereof.PATENT 9. The method of any one of claims 1 to 8, wherein the antifoulant composition comprises (i) a compound of Formula 1 and a compound of Formula 2, (ii) a compound of Formula 1 and a compound of Formula 3, (iii) a compound of Formula 1 and a compound of Formula 4, (iv) a compound of Formula 2 and a compound of Formula 3, (v) a compound of Formula 2 and a compound of Formula 4, (vi) a compound of Formula 3 and a compound of Formula 4, (vii) a compound of Formula 1, a compound of Formula 2, and a compound of Formula 3, (viii) a compound of Formula 1, a compound of Formula 2, and a compound of Formula 4, (ix) a compound of Formula 1, a compound of Formula 3, and a compound of Formula 4, and (x) a compound of Formula 1, a compound of Formula 2, a compound of Formula 3, and a compound of Formula 4.

10. The method of any one of claims 1 to 9, wherein the antifoulant composition comprises a compound of Formula 1 .

11. TheR1is C1-C30alkyl or C1-C30alkenyl; R2 and R3 are independently hydrogen or C1-C3 alkyl; R4 and R5 are independently hydrogen or methyl; R6is independently hydrogen or C1-C3alkyl; R8 and R9 are independently hydrogen, alkyl, or aryl; A1is independently –O- or -N(R8)-; n is an integer from 1 to 4; o is an integer from 1 to 3; and p is an integer from 1 to 30.

12. The method of claim 10 or 11, wherein the compound of Formula 1 has a structure of Formula 1A:PATENT .

13. The method of claim 12, wherein R1 is C10-C30 alkyl or C10-C30 alkenyl; R2, R3, R4, R5, R6, R8, and R9are independently hydrogen or methyl; A1is independently –O- or -N(R8)-; n is an integer of 1 or 2; and p is an integer from 1 to 30.

14. The method of claim 12, wherein R1 is C16-C24 alkyl or C16-C24 alkenyl; R2, R3, R4, R5, R6, R8, and R9are hydrogen; A1 is independently –O- or -N(R8)-; n is an integer of 2; and p is an integer from 6 to 24.

15. The method of any one of claims 1 to 14, wherein the antifoulant composition comprises a compound of Formula 2 .

16. The method of claim 15, wherein R1 is C1-C30 alkyl or C1-C30 alkenyl;PATENT R2, R3, R8and R9are independently hydrogen or C1-C3alkyl; R4 is hydrogen or methyl; R7is alkyl, substituted alkyl, aryl, or substituted aryl; A2is independently –OH, -N(R8)(R9), or –N(R8)C(O)R9; and n is an integer from 1 to 3.

17. The method of claim 15 or 16, wherein substituents for substituted alkyl and substituted aryl are carboxyl or hydroxyl.

18. The method of claim 15 or 16, wherein substituents for substituted alkyl are carboxyl.

19. The method of claim 15, wherein R1 is C10-C30 alkyl or C10-C30 alkenyl; R2, R3, R4, R8 and R9 are independently hydrogen or methyl; R7 is C1-C6 alkyl or phenyl; A2is independently –OH, -N(R8)(R9), or –N(R8)C(O)R9; and n is an integer of 2 or 3.

20. The method of claim 15, wherein R1is C16-C24alkyl or C16-C24alkenyl; R2, R3, R4, R8 and R9 are hydrogen; R7is C1-C3alkyl or phenyl; A2 is independently –OH, -N(R8)(R9), or –N(R8)C(O)R9; and n is an integer of 2.

21. The method of any one of claims 1 to 20, wherein the antifoulant composition comprises a compound of Formula 3 .PATENT 22. The method of claim 21, wherein R1is C1-C30alkyl or C1-C30alkenyl; R2, R3, R6, R8and R9are independently hydrogen or C1-C3alkyl; R4 and R5 are independently hydrogen or methyl; A1is independently –O-, -N(R8)-, or –N(R8)C(O)-; n and o are an integer from 1 to 3; and p is an integer from 8 to 40.

23. The method of claim 21, wherein R1 is C16-C24 alkyl or C16-C24 alkenyl; R2, R3, R4and R5are hydrogen; R6, R8 and R9 are independently hydrogen or methyl; A1 is independently –O-, -N(R8)-, or –N(R8)C(O)-; n and o are an integer or 2 or 3; and p is an integer from 10 to 30.

24. The method of any one of claims 1 to 23, wherein the antifoulant composition comprises a compound of Formula 4 .

25. The method of claim 24, wherein R1 is C1-C30 alkyl or C1-C30 alkenyl; R2, R3, R8, and R9 are independently hydrogen or C1-C3 alkyl; R4 is hydrogen or methyl; R7 is alkyl, substituted alkyl, aryl, or substituted aryl; A2is independently –OH, -N(R8)(R9), or –N(R8)C(O)R9; and n is an integer from 1 to 3.PATENT 26. The method of claim 24 or 25, wherein substituents for substituted alkyl and substituted aryl are carboxyl or hydroxyl.

27. The method of claim 24 or 25, wherein substituents for substituted alkyl are carboxyl.

28. The method of claim 24, wherein R1 is C10-C30 alkyl or C10-C30 alkenyl; R2, R3, R4, R8, and R9are independently hydrogen or methyl; R7 is C1-C6 alkyl or phenyl; A2is independently –OH, -N(R8)(R9), or –N(R8)C(O)R9; and n is an integer of 2 or 3.

29. The method of claim 24, wherein R1 is C16-C24 alkyl or C16-C24 alkenyl; R2, R3, R4, R8, and R9are hydrogen; R7 is C1-C3 alkyl or phenyl; A2is independently –OH, -N(R8)(R9), or –N(R8)C(O)R9; and n is an integer of 2.

30. The method of any one of claims 1 to 29, wherein the antifoulant composition further comprises a solvent.

31. The method of claim 30, wherein the solvent comprises water, an alcohol, an ester, an ether, a hydrocarbon, or a combination thereof.

32. The method of claim 30 or 31, wherein the organic solvent comprises water, methanol, ethanol, propanol, dimethyl ether, diethyl ether, or a combination thereof.

33. The method of any one of claims 1 to 32, wherein the concentration of the compound of Formula 1, 2, 3, 4, or a combination thereof in the fluid is from about 1 ppm byPATENT weight to about 5000ppm by weight based on the total weight of the compound of Formula 1, 2, 3, or 4 and solvent.

34. The method of claim 33, wherein the concentration of the compound of Formula 1, 2, 3, 4, or a combination thereof is from about 500 ppm to about 2000ppm.

35. The method of any one of claims 1 to 34, wherein the antifoulant composition is used to disperse or prevent organic foulant from agglomeration, precipitation, or deposition.

36. The method of any one of claims 1 to 35, wherein the antifoulant composition is added to the process fluid continuously.

37. The method of any one of claims 1 to 36, wherein the antifoulant composition is added to the process fluid intermittently.

38. The method of any one of claims 1 to 37 further comprising a chemical additive of a second solvent, a dispersant, a polymerization inhibitor, or a combination thereof.

39. A composition comprising aqueous sulfuric acid, an antifoulant composition, and a polymer of acrylic acid, an acrylate, methacrylic acid, a methacrylate, a methacrylamide, or a combination thereof, wherein the antifoulant composition comprises a compound of Formulae 1, 2, 3, or 4, or a combination thereof having the structures corresponding to: ;PATENT orR1is independently hydrogen, C1-C30alkyl, C1-C30alkenyl, aryl, alkaryl, or aralkyl; R2 and R3 are independently hydrogen, C1-C10 alkyl, aryl, or alkaryl; R4and R5are independently hydrogen or methyl; R6 is independently hydrogen or alkyl; R7is independently alkyl, substituted alkyl, aryl, or substituted aryl; R8 and R9 are independently hydrogen, alkyl, or aryl; A1 is independently –O-, -N(R8)-, or –N(R8)C(O)-; A2is independently –OH, -N(R8)(R9), or –N(R8)C(O)R9; n is an integer from 1 to 6; o is an integer from 1 to 4; and p is an integer from 1 to 50.

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