WO2021037578A1 - Procédé de fabrication de nvp contenant des polyacrylamides - Google Patents

Procédé de fabrication de nvp contenant des polyacrylamides Download PDF

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WO2021037578A1
WO2021037578A1 PCT/EP2020/072769 EP2020072769W WO2021037578A1 WO 2021037578 A1 WO2021037578 A1 WO 2021037578A1 EP 2020072769 W EP2020072769 W EP 2020072769W WO 2021037578 A1 WO2021037578 A1 WO 2021037578A1
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mole
monomer
water
amount
polymerization
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Alexander KRONAST
Tobias Joachim ZIMMERMANN
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Basf Se
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
    • C09K8/60—Compositions for stimulating production by acting on the underground formation
    • C09K8/84—Compositions based on water or polar solvents
    • C09K8/86—Compositions based on water or polar solvents containing organic compounds
    • C09K8/88—Compositions based on water or polar solvents containing organic compounds macromolecular compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/52—Amides or imides
    • C08F220/54—Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide
    • C08F220/56—Acrylamide; Methacrylamide
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
    • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
    • C08F220/52—Amides or imides
    • C08F220/54—Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide
    • C08F220/58—Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide containing oxygen in addition to the carbonamido oxygen, e.g. N-methylolacrylamide, N-(meth)acryloylmorpholine
    • C08F220/585—Amides, e.g. N,N-dimethylacrylamide or N-isopropylacrylamide containing oxygen in addition to the carbonamido oxygen, e.g. N-methylolacrylamide, N-(meth)acryloylmorpholine and containing other heteroatoms, e.g. 2-acrylamido-2-methylpropane sulfonic acid [AMPS]
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F226/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a single or double bond to nitrogen or by a heterocyclic ring containing nitrogen
    • C08F226/06—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a single or double bond to nitrogen or by a heterocyclic ring containing nitrogen by a heterocyclic ring containing nitrogen
    • C08F226/10—N-Vinyl-pyrrolidone
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
    • C09K8/58—Compositions for enhanced recovery methods for obtaining hydrocarbons, i.e. for improving the mobility of the oil, e.g. displacing fluids
    • C09K8/588—Compositions for enhanced recovery methods for obtaining hydrocarbons, i.e. for improving the mobility of the oil, e.g. displacing fluids characterised by the use of specific polymers

Definitions

  • the present invention relates to a process for producing water-soluble copolymers comprising (meth)acrylamide or a derivative thereof, 2-acrylamido-2-methylpropanesulfonic acid or a salt thereof, N-vinylpyrrolidone and a small amount of a water-soluble monoethylenically unsaturated carboxylic acid or a salt thereof, preferably (meth)acrylic acid or a salt thereof by adiabatic gel polymerization of an aqueous monomer solution comprising the abovementioned monomers and having a monomer concentration from 2 mole / kg to 3.3 mole / kg.
  • the monoethylenically unsaturated carboxylic acid acts as a polymerization booster and enables the manufacture of such N-vinylpyrrolidone containing monomers already at lower monomer concentrations.
  • the present invention furthermore relates to such water-soluble polymers and their use for recovering crude oil from subterranean, oil-bearing formations.
  • Water-soluble, high molecular weight homo- and copolymers of acrylamide may be used for various applications such as mining and oilfield applications, water treatment, sewage treatment, papermaking, and agriculture.
  • Examples of comonomers to be used besides acrylamide comprise comonomers comprising acidic groups such as acrylic acid, ATBS or salts thereof.
  • ATBS may in particular be used for polyacrylamides to be used in the presence of high concentrations of salts, in particular in the presence of salts comprising divalent cations such as earth alkali metal ions.
  • Copolymers comprising acrylamide, N-Vinyl-2-pyrrolidine (NVP) and optionally further comonomers are also known in the art. Such copolymers may be used for example for enhanced oil recovery. NVP is known to improve the thermal stability of polyacrylamides which is advantageous for enhanced oil recovery. Copolymers comprisng NVP and acrylamide and their use in oilfield applications are described for example in H. L Hsieh et al, Makromol. Chem., Macromol. Symp. 64, 121 - 135 (1992), US 5,080,809, WO 2010/133527 A2, WO 2013/108174 A1 or WO 2014/166858 A1.
  • a common polymerization technology for manufacturing high molecular weight polyacrylamides is the so called “gel polymerization”.
  • gel polymerization an aqueous monomer solution having a relatively high concentration of monomers, for example from 20 % by weight to 45 % by weight is polymerized by means of suitable polymerization initiators under essentially adiabatic conditions in an unstirred reactor thereby forming a polymer gel.
  • Such gels may be dried thereby obtaining a polymer powder. Powders may be transported to the location of use and dissolved in water for use. It is also known in the art to dissolve such gels in water, thereby directly obtaining aqueous polyacrylamide solutions.
  • WO 2010/133527 A2 discloses hydrophobically associating polymers, specifically hydrophobically associating polyacrylamides.
  • NVP may be used as comonomer.
  • Examples 11 and 12 specifically disclose the manufacture of a copolymer comprising acrylamide ( ⁇ 21 % by mole), NVP ( ⁇ 38 % by mole), ATBS or a cationic monomer ( ⁇ 36 % by mole), acrylic acid ( ⁇ 4 % by mole), and an associative monomer ( ⁇ 1 % by mole).
  • the monomers are polymerized in aqueous solution (monomer concentration about 50 % by weight for example 11 and about 53 % by weight for example 12, regarding to the total of all components of the aqueous solution).
  • the aqueous monomer solution is cooled to 5°C and thereafter polymerization initiated by irradiation with UV light thereby obtaining an aqueous polymer gel.
  • WO 2014/166858 A1 discloses water soluble polymers for oil and gas applications comprising acrylamide, NVP, and ATBS.
  • the amount of NVP is from 25 to 45 mole % and ATBS and NVP are used in equimolar amounts.
  • the polymers are manufactured by cooling an aqueous solution of the monomers to 5°C and initiating polymerization by redox initiators. The temperature rises to 80°C to 90°C in course of polymerization followed by aging of the polymerization mixure during 3 hours. The obtained gel is dried.
  • WO 2019/081328 A1 discloses a process for producing hydrophobically associating polyacrylamides by adiabatic gel polymerization thereby obtaining an aqueous polyacrylamide gel, wherein the concentration of the monomers is from 1 mole / kg to 3.3 mole / kg, the aqueous monomer solution has a temperature not exceeding 30°C, preferably -5°C to +5°C, before the onset of polymerization, and the temperature of the aqueous polyacrylamide gel after polymerization is from 45°C to 80°C, preferably 50°C to 70°C.
  • NVP may be used as comonomer.
  • WO 2020/079123 A1 discloses a process of fracturing subterranean formations wherein a hydrophobically associating copolymer comprising at least acrylamide and/or a derivative thereof and an associative monomer is used.
  • the copolymer is manufactured by adiabatic gel polymerization, wherein the concentration of the monomers is from 1 mole / kg to 3.3 mole / kg, the aqueous monomer solution has a temperature not exceeding 30°C, preferably -5°C to +5°C, before the onset of polymerization, and the temperature of the aqueous polyacrylamide gel after polymerization is from 45°C to 80°C, preferably 50°C to 70°C.
  • NVP may be used as comonomer.
  • US 5,080,809 discloses polymers useful in the recovery and processing of natural resources.
  • Table LVIII discloses a polymer comprising ⁇ 36.7 mole % N-vinylpyrrolidone, ⁇ 26.7 mole % acrylamide, -34.7 mole % of NaATBS and - 1.9 mole % of acrylic acid.
  • the document discloses only that the polymers were made by conventional solution polymerization technology using total solids levels of 20 to 30 % in distilled water at ambient temperature with about 0.1 phm of initiator.
  • WO 2019/081318 A1, WO 2019/081319 A1 , WO 2019/081320 A1 , WO 2019/081327 A1, and WO 2019/081330 A1 disclose the manufacture of aqueous polyacrylamide solutions on site in modular plants.
  • aqueous solutions comprising acrylamide and optionally further monoethylenically unsaturated comonomers are polymerized by adiabatic gel polymerization in a transportable polymerization unit which preferably has a volume of 20 m 3 to 30 m 3 .
  • Such a polymerization may be performed at a location A and thereafter the relocatable polymerization unit filled with the aqueous polyacrylamide gel is transported to another location B where the gel is removed from the polymerization unit, comminuted and dissolved in water thereby yielding an aqueous polyacrylamide solution.
  • Location B typically is a location where the aqueous polyacrylamide solutions are used, e.g. at an oil well or in mining area. Locations A and B may be apart from each other significantly, for example the distance may be up to 3000 km and the transport of the gel form location A to location B may last several days.
  • the temperature of the reactor contents raises from low temperatures to high temperatures and may approach for example 80°C to 95°C.
  • the transportable polymerization unit may have a volume of 20 m 3 to 30 m 3 . It goes without saying that a gel block having such a volume cools down only very slowly by dissipating heat. So, when transporting the reactor with the gel from a location A to a location B the gel or at least portions thereof- remains at high temperatures, for example at temperatures above 80°C for a period of several days. Keeping a polyacrylamide gel at such high temperatures for such long times may cause gel damage and deteriorated properties of the polymers.
  • NVP and ATBS containing polyacrylamides having satisfying properties can be obtained also at lower monomer concentrations by adding small amounts of acrylic acid or similar water-soluble ethylenically unsaturated carboxylic acids or salts thereof.
  • the present invention relates to a process for producing water-soluble copolymers by radically polymerizing an aqueous solution comprising water- soluble ethylenically unsaturated monomers in the presence of suitable initiators for radical polymerization under adiabatic conditions thereby obtaining an aqueous polyacrylamide gel, wherein the monomers comprise
  • the aqueous monomer solution additionally comprises 0.04 mole % to 5 mole % of at least one water-soluble, monoethylenically unsaturated carboxylic acid (D) or a salt thereof, wherein the amount relates to the total of all ethylenically unsaturated monomers in the aqueous solution,
  • the concentration of the monomers is from 2 mole / kg to 3.3 mole / kg, relating to the total of all components of the aqueous monomer solution,
  • the aqueous monomer solution has a temperature Ti not exceeding 30°C before the onset of polymerization, and > the peak temperature T2 of the aqueous polyacrylamide gel in course of polymerization is in a range from 45°C to 95°C.
  • the monomer (D) preferably is (meth)acrylic acid.
  • the amount of monomer (A) is from 8.5 mole % to 74.9 mole % and the amount of carboxylic acid (D) is from 0.1 mole % to 1.5 mole %.
  • the present invention relates to water-soluble copolymers comprising at least
  • (A) 8.5 mole % to 74.9 mole % of at least one monomer (A) selected from the group of (meth)acrylamide, N-methyl(meth)acrylamide, N,N'-dimethyl(meth)acrylamide or N-methylol(meth)acrylamide,
  • the present invention relates to the use of said water-soluble copolymers for recovering crude oil from a subterranean, oil-bearing formations.
  • an aqueous monomer solution comprising at least 4 different monoethylenically unsaturated monomers is used.
  • Monomers (A) are (meth)acrylamide or derivatives thereof, monomer (B) is 2-acrylamido-2- methylpropanesulfonic acid or a salt thereof (ATBS), monomer (C) is N-vinylpyrrolidone (NVP), and additionally a small amount of monomer(s) (D) is present.
  • Monomers (D) are water-soluble, monoethylenically unsaturated carboxylic acids or salts thereof, in particular (meth)acrylic acid or salts thereof.
  • the aqueous solution is polymerized in the presence of suitable initiators for radical polymerization under adiabatic conditions thereby obtaining an aqueous polyacrylamide gel.
  • suitable initiators for radical polymerization under adiabatic conditions thereby obtaining an aqueous polyacrylamide gel.
  • the monomer solution comprising NVP polymerizes more readily in the presence small amounts of such water-soluble, monoethylenically unsaturated carboxylic acids or salts thereof (D) than without such carboxylic acids. It is therefore possible to use less concentrated monomer solutions, thereby limiting the temperature of the gel after polymerization to less than 80°C and nevertheless obtaining polymers with suitable properties.
  • an aqueous solution comprising at least the abovementioned monoethylenically unsaturated monomers is provided. Besides the monomers, further additives and auxiliaries may be added to the aqueous monomer solution. As will be detailed below, before polymerization also suitable initiators for radical polymerization are added.
  • the aqueous monomer solution may also comprise additionally water-miscible organic solvents.
  • the amount of water should be at least 70 % by wt. relating to the total of all solvents used, preferably at least 85 % by wt. and more preferably at least 95 % by weight. In one embodiment, only water is used as solvent.
  • the aqueous monomer solution comprises at least one monoethylenically unsaturated monomer (A) selected from the group of (meth)acrylamide, N-methyl(meth)acryl-amide, N,N'- dimethyl(meth)acrylamide or N-methylol(meth)acrylamide.
  • Monomer (A) preferably is (meth)acrylamide, especially acrylamide. If mixtures of different monomers (A) are used, at least 50 mole% of the monomers (A) should be (meth)acrylamide, preferably acrylamide. In one embodiment of the invention, the monomer (A) is acrylamide.
  • the amount of monomers (A) is from 5 to 74.96 mole %, relating to the total of all ethylenically unsaturated monomers in the aqueous solution, preferably from 8 to 74.96 mole %, from 8 to 74.9 mole %, from 8.5 to 74.9 mole % or from 9 to 74.9 mole %. Further embodiments are mentioned below.
  • the aqueous monomer solution furthermore comprises 2-acrylamido-2- methylpropanesulfonic acid or a salt thereof (ATBS) (monomer B). Salts in particular may be alkali metal salts, preferably sodium salts.
  • ATBS 2-acrylamido-2- methylpropanesulfonic acid or a salt thereof
  • Salts in particular may be alkali metal salts, preferably sodium salts.
  • the amount of ATBS is from 5 to 45 mole %, relating to the total of all ethylenically unsaturated monomers in the aqueous solution; in other embodiments from 20 to 45 mole %. Further embodiments are mentioned below.
  • the aqueous monomer solution furthermore comprises N-vinylpyrrolidone (monomer C). The amount of NVP is from 20 to 45 mole %, relating to the total of all ethylenically unsaturated monomers in the aqueous solution. Further embodiments are mentioned below.
  • the aqueous monomer solution comprises at least one water-soluble, monoethylenically unsaturated carboxylic acid (D) or a salt thereof.
  • Salts in particular may be alkali metal salts, preferably sodium salts.
  • water-soluble in the context of this invention means that the monomers are to be soluble in the aqueous monomer solution to be used for polymerization in the desired use concentration. It is thus not absolutely necessary that the monomers to be used are miscible with water without any gap; instead, it is sufficient if they meet the minimum requirement mentioned. It is to be noted that the presence of the monomers mentioned above in the monomer solution might enhance the solubility of other monomers as compared to water only. In general, the solubility of water-soluble monomers in water at room temperature should be at least 50 g/l, preferably at least 100 g/l.
  • the carboxylic acid (D) preferably is a monocarboxylic acid or a salt thereof, preferably an aliphatic monocarboxylic acid having not more than 5 carbon atoms.
  • the carboxylic acid (D) is at least one selected from the group of acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, and vinylacetic acid or salts thereof.
  • the carboxylic acid (D) is (meth)acrylic acid or a salt thereof, preferably acrylic acid or a salt thereof.
  • the amount of monomers (D) is from 0.04 to 5 mole %, relating to the total of all ethylenically unsaturated monomers in the aqueous solution, in particular from 0.04 to 2 mole %, preferably from 0.07 to 2 mole % or from 0.1 to 2 mole %. In preferred embodiments, the amount is from 0.04 to 1,5 mole %, preferably from 0.07 to 1,5 mole % or from 0.1 to 1,5 mole %. In further preferred embodiments, the amount is from 0.04 to 1 mole %, preferably from 0.07 to 1 mole % or from 0.1 to 1 mole %.
  • the aqueous monomer solution may optionally comprise additional water-soluble ethylenically unsaturated monomers different from the monomers (A), (B), (C), and (D) mentioned above.
  • additional monomers which optionally may be used are preferably monoethylenically unsaturated monomers. Examples comprise N-vinylformamide, N-Vinylcaprolactam or N- vinylacetamide.
  • Additional monomers may also comprise carboxylic acid groups, however, preferably besides the monomers (D) no other monomers comprising carboxylic acid groups are present.
  • Crosslinking monomers comprising more than one ethylenically unsaturated group may be used in exceptional cases in limited amounts, however preferably, no such monomers are used. If present at all, their amount should be less than 0.5 mole %, more preferably less than 0.1 mole % relating to the total of all monomers in the aqueous monomer solution.
  • the aqueous monomer solution additionally comprises at least one monomer (E) selected from monomers having the general formula
  • H 2 C C(R 1 )-0-(-CH 2 -CH(R 2 )-0-)k-R 3 (I),
  • H 2 C C(R 1 )-R 4 -0-(-CH 2 -CH(R 5 )-0-)x-(-CH 2 -CH(R 6 )-0-) y -(-CH 2 -CH 2 0-)z-R 7 (III).
  • Such monomers (E) comprise hydrophilic and hydrophobic moieties. When polymerized with water-soluble monomers the polymerization yields water-soluble polymers comprising a small amount of hydrophobic side chains. In aqueous solution, said side chains may associate with each other, thereby increasing the viscosity of a solution comprising such polymers. Polymers comprising such type of monomers are therefore also called “hydrophobically associating polymers”.
  • R 1 is H or methyl, preferably H.
  • the R 2 moieties are each independently H, methyl or ethyl, preferably H or methyl, with the proviso that at least 70 mole % of the R 2 radicals are H.
  • This block is thus a polyoxyethylene block which may optionally include certain proportions of propylene oxide and/or butylene oxide units, preferably a pure polyoxyethylene block.
  • the number of alkylene oxide units k is a number from 10 to 80, preferably 12 to 60, more preferably 15 to 50 and, for example, 20 to 40. It will be apparent to the person skilled in the art in the field of alkylene oxides that the values mentioned are mean values.
  • R 3 is an aliphatic and/or aromatic, straight-chain or branched hydrocarbyl radical having 8 to 40 carbon atoms, preferably 12 to 32 carbon atoms. In one embodiment, the aliphatic hydrocarbyl groups are those having 8 to 22 and preferably 12 to 18 carbon atoms.
  • groups include n-octyl, n-decyl, n-dodecyl, n-tetradecyl, n-hexadecyl or n- octadecyl groups.
  • the groups are aromatic groups, especially substituted phenyl radicals, especially distyrylphenyl groups and/or tristyrylphenyl groups.
  • R 1 has the definition already defined, i.e. R 1 is H or a methyl group, preferably H.
  • R 4 is a single bond or a divalent linking group selected from the group consisting of -(C n H 2n )-, -0-(Cn'H 2n' )- and -C(0)-0-(Cn"H 2n' )- ⁇
  • n in each case is a natural number from 1 to 6; n 1 and n" are each a natural number from 2 to 6.
  • the -(C n H 2n )-, -(C n H 2n’ )- and -(C n H 2n )- groups are preferably linear aliphatic hydrocarbyl groups.
  • the -(C n H 2n )- group is a group selected from -CH 2 -, -CH 2 -CH 2 - and -CH 2 -CH 2 - CH 2 -, more preferably a methylene group -CH 2 -.
  • the -0-(0 h ⁇ 2h )- group is a group selected from -0-CH 2 -CH 2 -, -0-CH 2 -CH 2 -CH 2 - and -0-CH 2 -CH 2 -CH 2 -CH 2 -, more preferably -0-CH 2 -CH 2 -CH 2 -CH 2 -.
  • the -C(0)-0-(C n H 2n” )- group is a group selected from -C(0)-0-CH 2 -CH 2 -, -C(0)0- CH(CH 3 )-CH 2 -, -C(0)0-CH 2 -CH(CH 3 )-, -C(0)0-CH 2 -CH 2 -CH 2 - and -C(0)0-CH 2 -CH 2 - CH 2 -CH 2 -CH 2 -CH 2 -, more preferably -C(0)-0-CH 2 -CH 2 - and -C(0)0-CH 2 -CH 2 -CH 2 -CH 2 -, and most preferably is -C(0)-0-CH 2 -CH 2 -.
  • the R 4 group is a -0-(C n' H 2n' )- group, most preferably a group -0-CH 2 -CH 2 -CH 2 -CH 2 -.
  • the R 5 radicals are independently H, methyl or ethyl, preferably H or methyl, with the proviso that at least 70 mole% of the R 5 radicals are H.
  • at least 80 mole% of the R 5 radicals are H, more preferably at least 90 mole%, and they are most preferably exclusively H.
  • This block is thus a polyoxyethylene block which may optionally include certain proportions of propylene oxide and/or butylene oxide units, preferably a pure polyoxyethylene block.
  • the number of alkylene oxide units x is a number from 10 to 50, preferably 12 to 40, more preferably 15 to 35, even more preferably 20 to 30 and, for example, 23 to 26. It will be apparent to the person skilled in the art in the field of polyalkylene oxides that the numbers mentioned are mean values of distributions.
  • the R 6 radicals are independently hydrocarbyl radicals of at least 2 carbon atoms, for example 2 to 10 carbon atoms, preferably 2 or 3 carbon atoms. This may be an aliphatic and/or aromatic, linear or branched carbon radical. Preference is given to aliphatic radicals.
  • R 6 radicals examples include ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl or n-decyl and phenyl.
  • suitable radicals include ethyl, n-propyl, n-butyl, n-pentyl, especially ethyl and/or n-propyl radicals, and more preferably ethyl radicals.
  • the -(-CH 2 -CH(R 6 )-0-) y - block is thus a block consisting of alkylene oxide units having at least 4 carbon atoms.
  • the number of alkylene oxide units y is a number from 5 to 30, preferably 8 to 25.
  • z is a number from 0 to 10, preferably 0 to 5, i.e. the terminal block of ethylene oxide units is thus only optionally present. In one embodiment of the invention, z is a number > 0 to 10, especially > 0 to 10 and, for example, 1 to 4.
  • the R 7 radical is H or a preferably aliphatic hydrocarbyl radical having 1 to 30 carbon atoms, preferably 1 to 10 and more preferably 1 to 5 carbon atoms.
  • R 7 is preferably H, methyl or ethyl, more preferably H or methyl and most preferably H.
  • At least one of the monomers (B) is a monomer of the formula (III).
  • a mixture of at least two different monomers (B) of the formula (III) is used, where the radicals R 1 , R 4 , R 5 , R 6 , and R 7 and the indices x and y are the same in each case.
  • z 0 in one of the monomers, while z is a number > 0 to 10, preferably 1 to 4, in the other.
  • Said preferred embodiment is thus a mixture of the following composition:
  • H 2 C C(R 1 )-R 4 -0-(-CH 2 -CH(R 5 )-0-) x -(-CH 2 -CH(R 6 )-0-) y -H (Ilia) and
  • H 2 C C(R 1 )-R 4 -0-(-CH 2 -CH(R 5 )-0-) x -(-CH 2 -CH(R 6 )-0-) y -(-CH 2 -CH 2 0-) z -H (lllb), where the radicals and indices have the definition outlined above, including the preferred embodiments thereof, with the proviso that, in the formula (lllb), z is a number > 0 to 10.
  • R 1 is H
  • R 4 is -0-CH 2 CH 2 CH 2 CH 2 -
  • R 5 is H
  • R 6 is ethyl
  • x is 20 to 30, preferably 23 to 26
  • y is 12 to 25, preferably 14 to 18, and
  • z is 3 to 5.
  • the monomers (E) of the formulae (I), (II) and (III), the preparation thereof and acrylamide copolymers comprising these monomers and the preparation thereof are known in principle to those skilled in the art, for example from WO 85/03510 A1 , WO 2010/133527 A1 , WO 2012/069478 A1, WO 2014/095608 A1, WO 2014/095621 A1 and WO 2015/086486 A1 and in the literature cited therein.
  • monomers (E) are present, their amount may be from 0.005 mole % to 1 mole %, in par ticular, from 0.005 mole % to 0.2 mole %, and for example from 0.005 mole % to 0.1 mole %.
  • monomers (A), (B), (C), and (D) are present.
  • the following table shows the amounts of monomers (A), (B), (C), and (D) in the aqueous solution and in the resulting copolymer for several embodiments.
  • the amounts are as follows:
  • the amounts are as follows:
  • the amounts are as follows:
  • the amounts mentioned in both tables relate to the total amount of all monomers in the aqueous monomer solution.
  • only the monomers (A), (B), (C), (D), and (E) are present, i.e. the amounts of monomers in each column of the tables sum up to 100 %.
  • monomers (B) and (C) are used in equimolar amounts.
  • equimolar shall mean, that the amounts of the monomers (B) and (C) in the polymer, each of them relating to the total of all monomers in the copolymer, differ by not more than 1 mole %.
  • the amounts shall be deemed to be equimolar, however, if the amount of (B) is 30 mole % and the amount of (C) is 32 mole%, the amounts shall no longer be deemed to be equimolar.
  • the concentration of the monomers in the aqueous monomer solution is from 2 mole / kg to 3.3 mole / kg, relating to the total of all components of the aqueous monomer solution.
  • the concentration is from 2.5 mole / kg to 3.3 mole / kg, more preferably from 2.5 mole % to 3.0 mole %, and for example from 2.5 to 2.8 mole %.
  • further additives and auxiliaries may be added to the aqueous monomer solution.
  • suitable initiators for radical polymerization are added before polymerization.
  • further additives and auxiliaries comprise complexing agents, defoamers, surfactants, stabilizers, and bases or acids for adjusting the pH value.
  • the pH- value of the aqueous monomer solution is adjusted to values from pH 5 to pH 8, preferably from 5 to 7, and for example from pH 6 to pH 7.
  • the aqueous monomer solution comprises at least one stabilizer for the prevention of polymer degradation.
  • stabilizers for the prevention of polymer degradation are what are called “free-radical scavengers”, i.e. compounds which can react with free radicals (for example free radicals formed by heat, light, redox processes), such that said radicals can no longer attack and hence degrade the polymer.
  • free-radical scavengers i.e. compounds which can react with free radicals (for example free radicals formed by heat, light, redox processes), such that said radicals can no longer attack and hence degrade the polymer.
  • the stabilizers may be selected from the group of non-polymerizable stabilizers and polymerizable stabilizers.
  • Polymerizable stabilizers comprise a monoethylenically unsaturated group and become incorporated into the polymer chain in course of polymerization.
  • Non-polymerizable stabilizers don’t comprise such monoethylenically unsaturated groups and are not incorporated into the polymer chain.
  • stabilizers are non-polymerizable stabilizers selected from the group of sulfur compounds, sterically hindered amines, N-oxides, nitroso compounds, aromatic hydroxyl compounds or ketones.
  • sulfur compounds include thiourea, substituted thioureas such as N,N‘- dimethylthiourea, N,N‘-diethylthiourea, N,N‘-diphenylthiourea, thiocyanates, for example ammonium thiocyanate or potassium thiocyanate, tetramethylthiuram disulfide, and mercaptans such as 2-mercaptobenzothiazole or 2-mercaptobenzimidazole or salts thereof, for example the sodium salts, sodium dimethyldithiocarbamate, 2,2‘-dithiobis(benzothiazole), 4,4‘-thiobis(6-t-butyl-m-cresol).
  • substituted thioureas such as N,N‘- dimethylthiourea, N,N‘-diethylthiourea, N,N‘-diphenylthiourea
  • thiocyanates for example ammonium thiocyanate or potassium
  • Further examples include dicyandiamide, guanidine, cyanamide, paramethoxyphenol, 2,6-di- t-butyl-4-methylphenol, butylhydroxyanisole, 8-hydroxyquinoline, 2,5-di(t-amyl)- hydroquinone, 5-hydroxy-1, 4-naphthoquinone, 2,5-di(t-amyl)hydroquinone, dimedone, propyl 3,4,5-trihydroxybenzoate, ammonium N-nitrosophenylhydroxylamine, 4-hydroxy-2, 2,6,6- tetramethyoxylpiperidine, (N-(1 ,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine and 1,2,2,6,6-pentamethyl-4-piperidinol.
  • sterically hindered amines such as 1,2,2,6,6-pentamethyl-4-piperidinol and sulfur compounds, preferably mercapto compounds, especially 2-mercaptobenzothiazole or 2-mercaptobenzimidazole or the respective salts thereof, for example the sodium salts, and particular preference is given to 2-mercaptobenzothiazole or salts thereof, for example the sodium salts.
  • the amount of such non-polymerizable stabilizers -if present- may be from 0.1 % to 2.0 % by weight, relating to the total of all monomers in the aqueous monomer solution, preferably from 0.15 % to 1.0 % by weight and more preferably from 0.2 % to 0.75 % by weight.
  • the stabilizers are polymerizable stabilizers substituted by a monoethylenically unsaturated group.
  • stabilizers comprising monoethylenically unsaturated groups comprise (meth)acrylic acid esters of 1, 2,2,6, - pentamethyl-4-piperidinol or other monoethylenically unsaturated groups comprising 1,2,2,6,6-pentamethyl-piperidin-4-yl groups.
  • suitable polymerizable stabilizers are disclosed in WO 2015/024865 A1, page 22, lines 9 to 19.
  • the stabilizer is a (meth)acrylic acid ester of 1,2,2,6,6-pentamethyl-4- piperidinol.
  • the amount of polymerizable stabilizers -if present- may be from 0.01 to 2% by weight, based on the sum total of all the monomers in the aqueous monomer solution, preferably from 0.02 % to 1 % by weight, more preferably from 0.05 % to 0.5 % by weight.
  • the aqueous monomer solution comprises at least one non- polymerizable surfactant.
  • suitable surfactants including preferred amounts have been disclosed in WO 2015/158517 A1, page 19, line, 23 to page 20, line 27.
  • the surfactants lead to a distinct improvement of the product properties.
  • non-polymerizable surfactant may be used in an amount of 0.1 to 5% by weight, for example 0.5 to 3 % by weight based on the amount of all the monomers used.
  • the aqueous monomer solution is polymerized in the presence of suitable initiators for radical polymerization under adiabatic conditions thereby obtaining an aqueous polyacrylamide gel.
  • suitable initiators for radical polymerization under adiabatic conditions thereby obtaining an aqueous polyacrylamide gel.
  • adiabatic gel polymerization Such a polymerization technique is also briefly denominated by the skilled artisan as “adiabatic gel polymerization”. Reactors for adiabatic gel polymerization are unstirred.
  • polymer gel has been defined for instance by L. Z. Rogovina et al. , Polymer Science, Ser.
  • adiabatic shall consequently be understood to mean “essentially adiabatic”, meaning that the reactor is not supplied with any heat from the outside during the polymerization, i.e. is not heated, and the reactor is not cooled during the polymerization.
  • adiabatic shall consequently be understood to mean “essentially adiabatic”, meaning that the reactor is not supplied with any heat from the outside during the polymerization, i.e. is not heated, and the reactor is not cooled during the polymerization.
  • - according to the internal temperature of the reactor and the ambient temperature certain amounts of heat can be released or absorbed via the reactor wall because of temperature gradients.
  • the polymerization of the aqueous monomer solution generates polymerization heat. Due to the adiabatic reaction conditions the temperature of the polymerization mixture increases in course of polymerization.
  • Suitable reactors for performing adiabatic gel polymerizations are known in the art.
  • cylindrical reactors may be used.
  • the polymerization can be conducted using (partly) conical reactors, as described, for example, by US 5,633,329 or US 7,619,046 B2.
  • the reactor comprises a cylindrical upper part and a conical part at its lower end. At the lower end, there is a bottom opening which may be opened and closed. After polymerization, the aqueous polyacrylamide gel formed is removed through the opening.
  • the polymerization is performed in the presence of suitable initiators for radical polymerization.
  • suitable initiators for radical polymerization in particular for adiabatic gel polymerization are known to the skilled artisan.
  • redox initiators are used for initiating.
  • Redox initiators can initiate a free-radical polymerization even at temperatures of less than +5°C.
  • redox initiators are known to the skilled artisan and include systems based on Fe 2 7Fe 3+ - H2O2, Fe 2 7Fe 3+ - alkyl hydroperoxides, alkyl hydroperoxides - sulfite, for example t-butyl hydroperoxide - sodium sulfite, peroxides - thiosulfate or alkyl hydroperoxides - sulfinates, for example alkyl hydroperoxides/ hydroxymethane-sulfinates, for example t-butyl hydroperoxide - sodium hydroxymethanesulfinate.
  • water-soluble azo initiators may be used.
  • the azo initiators are preferably fully water-soluble, but it is sufficient that they are soluble in the monomer solution in the desired amount.
  • azo initiators having a 10 h ti/2 in water of 40°C to 70°C may be used.
  • the 10-hour half-life temperature of azo initiators is a parameter known in the art. It describes the temperature at which, after 10 h in each case, half of the amount of initiator originally present has decomposed.
  • Suitable azo initiators having a 10 h temperature between 40 and 70°C include 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride (10 h ti/2 (water): 44°C), 2,2'-azobis(2-methylpropionamidine) dihydrochloride (10 h ti/2 (water): 56°C), 2,2'-azobis[N- (2-carboxyethyl)-2-methylpropionamidine hydrate (10 h ti/2 (water): 57°C), 2,2'-azobis ⁇ 2-[1- (2-hydroxyethyl)-2-imidazolin-2-yl]propane ⁇ dihydrochloride (10 h ti/2 (water): 60°C), 2,2'- azobis(1-imino-1-pyrrolidino-2-ethylpropane) dihydrochloride (10 h ti/2 (water): 67°C) or azobis(is
  • a combination of at least one redox initiator and at least one azo initiator is used.
  • the redox initiator efficiently starts polymerization already at temperatures below +5°C.
  • the reaction mixture heats up, also the azo initiators decompose and also start polymerization.
  • the temperature of the aqueous monomer solution before the onset of polymerization shall be denominated as Ti and the peak temperature of the aqueous polymer gel in course of polymerization shall be denominated as T2. It goes without saying that T2 > Ti.
  • peak temperature refers to the highest temperature reached in course of polymerization. In an ideal adiabatic system, the temperature should stay at the highest temperature also after polymerization, however, in “the real world” after polymerization, the temperature may start decreasing a bit from the peak temperature due to some unavoidable loss of heat.
  • the temperature Ti should not exceed 30°C. In particular, Ti should not exceed 25°C, preferably not 15°C and more preferably, Ti should not exceed 5°C. In one embodiment, Ti is in the range from -5°C to +5°C, for example from -5°C to 0°C.
  • the temperature T2 reached in course of polymerization is not influenced by external heating or cooling but only depends on the polymerization parameters chosen. By suitable choice of the polymerization parameters, the skilled artisan can adjust T2.
  • the temperature increase in course of polymerization basically depends on the heat of polymerization generated in course of polymerization, the heat capacity of contents of the polymerization unit and the temperature Ti of the monomer solution, i.e. the temperature before the onset of polymerization. Due to high water contents of the mixture for polymerization the heat capacity of the mixture for polymerization is dominated by the heat capacity of water and it may of course be measured.
  • the polymerization heat per mole for common monoethylenically unsaturated monomers is known in the art and may therefore be gathered from the scientific literature. Of course, it may also be measured. So, it is possible for the skilled artisan to calculate at least roughly the heat of polymerization for specific monomer compositions and specific monomer concentrations.
  • T2 Ti + [(polymerization heat) / (heat capacity)].
  • the starting temperature Ti and the concentration of the monomers in the aqueous monomer solution is selected such, that the temperature T2 from 45°C to 95°C, in particular from 80°C to 95°C, preferably from 50°C to 70°C, for example from 55°C to 70°C.
  • Ti is from -5°C to + 5°C and T2 is from 45°C to 80°C, preferably from 50°C to 80°C, more preferably from 50°C to 70°C and for example from 55°C to 70°C.
  • oxygen from the reactor and the aqueous monomer solution to be polymerized is removed in basically known manner.
  • Deoxygenation is also known as inertization.
  • inert gases such as nitrogen or argon may be injected into the reactor filled with the aqueous monomer solution.
  • the polymerization can be carried out as batch polymerization or as continuous polymerization.
  • the polymerization reactor is filled with the aqueous monomer solutions, the monomers are polymerized, and after polymerization the aqueous polyacrylamide gel is removed from the reactor.
  • the aqueous polyacrylamide gel may be removed by applying pressure onto the gel and pressing it through an opening in the polymerization reactor.
  • pressure may be generated by mechanical means such as a piston, by means of gases such as compressed air, nitrogen, argon or by means of aqueous fluids, in particular water.
  • the polymerization reactor continuously is fed with a monomer solution, the monomers are polymerized while moving through the reactor and aqueous polyacrylamide gel is continuously removed from the reactor.
  • a monomer solution may be fed at the upper end and the aqueous polyacrylamide gel is removed at the lower end through the bottom opening.
  • the transport of the polymerizing mixture through the reactor is affected by gravity and it may be supported by gas pressure.
  • a continuous polymerization may be a 2-step process, comprising a pre-polymerization in a first reactor and continuing the polymerization in a second reactor.
  • the pre-polymerization step typically not more than 25 % of the monomers are polymerized, so the product from the first reactor is somewhat viscos but not yet a solid gel.
  • the risk of bypassing is significantly diminished by feeding a higher viscos pre-polymerized solution.
  • a continuous polymerization may comprise at least the following sub-steps
  • the positive displacement pump is a progressive progressive cavity pump.
  • a continuous 2-step polymerization process in which a pre-polymerization is carried out in a first reactor device comprising a positive displacement pump is described in more detail in WO 2014/049513 A1.
  • the aqueous polyacrylamide gel obtained may by be further processed by drying. Downstream processing may include further steps such as sieving and grinding thereby yielding a polyacrylamide powder.
  • Such polyacrylamide powders may be transported to the location of use, e.g. to an oilfield or a mining area. At such locations, the polyacrylamide powders may be dissolved in water or aqueous fluids for use.
  • the aqueous polyacrylamide gel obtained may also be further processed by directly dissolving the aqueous polyacrylamide gel in aqueous fluids, in particular water, thereby obtaining an aqueous polyacrylamide solution.
  • aqueous polyacrylamide gel may be transported to the location of use and dissolved at the location of use.
  • the process according to the present invention may be performed on-site, i.e. at the location of use such as on an oilfield or in a mining area.
  • the invention also relates to water-soluble copolymers comprising at least
  • Such copolymers may be manufactured by the process mentioned above. Details about the monomers (A), (B), (C), and (D) and their amounts including preferred embodiments have already been mentioned above and we refer to the respective passages in the specification.
  • the water-soluble copolymer comprises only the monomers (A), (B), (C) and (D).
  • the water-soluble copolymers comprise -besides the monomers (A), (B), (C), and (D) additionally at least one monomer (E).
  • Monomers (E) and water-soluble copolymers comprising monomers (E) have been described in detail above and we refer to said passages.
  • the water-soluble copolymers according to the present invention may be used for various purposes, for example for mining applications, oilfield applications, water treatment, waste water cleanup, paper making or agricultural applications.
  • oilfield applications include enhanced oil recovery, oil well drilling or the use as friction reducers, for example friction reducers for fracturing fluids.
  • water-soluble copolymers according to the present invention are used for enhanced oil recovery.
  • the present invention also relates a method for producing mineral oil from subterranean, oil-bearing formations by injecting an aqueous fluid comprising at least 0.1 % by wt. to 2 % by wt. of said water-soluble copolymers through at least one injection well into a subterranean formation, causing to flow said aqueous fluid through the subterranean formation towards at least one production well distant from the injection well and recovering crude oil from said production well(s).
  • At least one production well and at least one injection well are sunk into the mineral oil deposit.
  • a deposit will be provided with a plurality of injection wells and with a plurality of production wells.
  • An aqueous fluid is injected into the mineral oil deposit through the at least one injection well, and mineral oil is withdrawn from the deposit through at least one production well.
  • the polymer flood By virtue of the pressure generated by the aqueous fluid injected, called the “polymer flood”, the mineral oil flows in the direction of the production well and is produced through the production well.
  • the term “mineral oil” does not of course just mean a single-phase oil; instead, the term also encompasses the customary crude oil-water emulsions.
  • the aqueous fluid for injection can be made up in freshwater or else in water comprising salts, such as seawater or formation water or mixtures thereof.
  • the aqueous fluid has a salinity of 10,000 ppm to 120,000 ppm.
  • the aqueous injection fluid may of course optionally comprise further components.
  • further components include biocides, stabilizers, free-radical scavengers, initiators, surfactants, cosolvents, bases and complexing agents.
  • the concentration of the polyacrylamides in the injection fluid should be chosen as such that the aqueous formulation has the desired viscosity for the end use.
  • the viscosity of the formulation should generally be at least 5 mPas (measured at 25°C and a shear rate of 7 s 1 ), preferably at least 10 mPas.
  • the concentration of the water-soluble copolymers in the injection fluid is 0.02 to 2% by weight based on the sum total of all the components in the aqueous formulation.
  • the amount is preferably 0.05 to 1 % by weight, for example from 0.1 to 0.5% by weight.
  • the water-soluble copolymers according to the present invention may be used for any kind of subterranean formation.
  • the subterranean formation may have a formation temperature from 40 to 120°C, preferably from 60°C to 120°C, for example from 60°C to 100°C.
  • the salt mixture used had the following composition:
  • the filterability of the polymer solutions was characterized using the MPFR value (Millipore filtration ratio).
  • the MPFR value characterizes the deviation of a polymer solution from ideal filtration characteristics, i.e. when there is no reduction of the filtration rate with increasing filtration. Such a reduction of the filtration rate may result from the blockage of the filter in course of filtration.
  • the MPFR value was calculated by the following formula
  • MPFR (tl 80 g - tl 60 g) / ( ⁇ dq g - t60 g) ⁇
  • T X g is the time at which the amount solution specified passed the filter, i.e. tiso g is the time at which 180 g of the polyacrylamide solution passed the filter.
  • API RP 63 Recommended Practices for Evaluation of Polymers Used in Enhanced Oil Recovery Operations”, American Petroleum Institute
  • a polymer solution (polymer concentration: 5000 ppm) in synthetic sea water is diluted to 1000 ppm with synthetic sea water.
  • the gel fraction is given as ml_ of gel residue on the sieve when 250 g 1000 ppm polymer solution are filtered over 200 pm sieve and consequently washed with 2 I of tab water.
  • Copolymer comprising 50.0 mole% (29.5 wt.%) of acrylamide, 25.0 mole% (47.5 wt.%) of sodium ATBS, and 25.0 mole% (23.0 wt.%) NVP
  • a 1 L glass flask with magnetic stirrer, pH meter and temperature probe was initially charged with 90 g of deionized water, 163.47 g of a 50 % aqueous solution of NaATBS, and 97.53 g of acrylamide (52 % by weight in water). Subsequently, 0.40 g of a commercially available silicone defoamer (Xiameter ® AFE-0400), 39.55 g of NVP (100 %), 2.0 g of a 0.1 wt.% aqueous solution of sodium hypophosphite hydrate, and 1.2 g of a 5 % aqueous solution of diethylenetriamine- pentaacetic acid - pentasodium salt were added.
  • the monomer concentration was adjusted to 43 % by weight relating to the total of all components of the monomer mixture which corresponds to a monomer concentration of 3.57 moles of monomers / kg of the monomer solution.
  • the temperature of the monomer solution was adjusted to the initiation temperature of 0 °C.
  • the solution was transferred to a Dewar vessel, the temperature probe for the temperature recording was inserted, and the flask was purged with nitrogen for 45 minutes.
  • the polymerization was initiated with 2.4 g of a 10 % aqueous solution of the water-soluble azo initiator 2,2‘-azobis(2-methylpropionamidine) dihydrochloride (Wako V-50), 0.32 g of a 1 % t-BHP solution and 0.64 g of a 1 % sodium sulfite solution. With the onset of the polymerization, the temperature rose to about 87 °C within about 20 min. A solid polymer gel was obtained.
  • Copolymers comprising 49 mole% (28.8 wt. %) of acrylamide, 25.0 mole% (47.4 wt. %) of sodium ATBS, 25.0 mole% NVP (23.0 wt. %), and 1.0 mole% (0.8 wt. %) sodium acrylate
  • Comparative examples C1 to C3 were repeated, except that 1 mole % of sodium acrylate was used and the amount of acrylamide was reduced to 49 mole %.
  • Example 1 Monomer concentration: 3.57 mole / kg (43 % by weight)
  • Example 2 Monomer concentration: 3.40 mole / kg (41 % by weight)
  • Example 3 Monomer concentration: 3.23 mole / kg (39 % by weight)
  • example 3 as compared to comparative example 3 polymerized well.
  • the temperatures in course of polymerization is represented in Figure 2. The results are summarized in table 1.
  • the comparative examples C1 , C2, and C3 show that the polymerization rate for the polymers comprising NVP significantly decreases with decreasing concentration.
  • the polymerization works at a monomer concentration of 3.57 moles / kg (43 % by wt.) and of 3.40 moles / kg (41 % by wt.) -although already slower- but at a monomer concentration of 3.23 moles / kg (39 % by wt.) no longer polymers having a suitable quality were obtained.
  • adding to the reaction mixture only 1 mole % of sodium acrylate a very significant increase of the polymerization rate is observed and polymer gels having satisfying properties are obtained.
  • a polymerization at a monomer concentration of 3.23 moles / kg (39 % by wt.) was possible while in comparative example 3 a polymerization was no longer possible.
  • Copolymers comprising 30.0 mole% (15.2 wt. %) of acrylamide, 35.0 mole% (57.1 wt. %) of sodium ATBS, and 35.0 mole% (27.7 wt. %) NVP
  • the synthesis was carried out according to the procedure of comparative of comparative example 1 except that the amounts of NVP and ATBS were increased to 35 % by weight and the amount of acrylamide was decreased to 30 mole %.
  • Comparative Example 4 Monomer concentration: 3.56 mole / kg (50 % by weight) Comparative Example 5: Monomer concentration: 3.42 mole / kg (48 % by weight) Comparative Example 6: Monomer concentration: 3.24 mole / kg (45.5 % by weight)
  • Copolymers comprising 29.0 mole% (14.7 wt. %) of acrylamide, 35.0 mole% (57.0 wt. %) of sodium ATBS, and 35.0 mole% (27.6 wt. %) NVP, and 1.0 mole % (0.7 wt. %) Sodium acrylate
  • Comparative examples C1 to C3 were repeated, except that 1 mole % of sodium acrylate was used and the amount of acrylamide was reduced to 29 mole %.
  • Example 4 Monomer concentration: 3.56 mole / kg (50 % by weight)
  • Example 5 Monomer concentration: 3.42 mole / kg (48 % by weight)
  • Example 6 Monomer concentration: 3.24 mole / kg (45.5 % by weight)
  • the amounts of NVP and ATBS are 35 mole % each as compared to 25 mole % each in examples and comparative examples 1, 2, and 3.
  • Examples 4, 5, and 6 demonstrate the same effect as above.
  • no significant temperature rise was observed for all comparative examples (see figure 3 and table 1) and no satisfactory polymers were obtained.
  • adding to the reaction mixture only 1 mole % of sodium acrylate a very significant increase of the polymerization rate is observed and polymer gels having satisfying properties are obtained (see figure 4 and table 1).
  • the macromonomer has the formula:
  • H2C CH-0-CH2CH2CH2CH2-0-(CH2CH20)24.5-(CH2CH(C2H5)0) 16 -(CH2CH 2 0) 3 .5H
  • a 1 L glass flask with magnetic stirrer, pH meter and temperature probe was initially charged with 80 g of deionized water, 157.38 g of a 50 wt. % aqueous solution of NaATBS, and 95.64 g of acrylamide (52 % by weight in water).
  • the monomer concentration was adjusted to 43 % by weight relating to the total of all components of the monomer mixture which corresponds to a monomer concentration of 3.44 moles of monomers / kg of the monomer solution.
  • the temperature of the monomer solution was adjusted to the initiation temperature of 0 °C.
  • the solution was transferred to a Dewar vessel, the temperature probe for the temperature recording was inserted, and the flask was purged with nitrogen for 45 minutes.
  • the polymerization was initiated with 2.4 g of a 10 % aqueous solution of the water-soluble azo initiator 2, 2'-Azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride (Wako VA-044), 0.32 g of a 1 wt. % t-BHP solution and 0.64 g of a 1 wt % sodium sulfite solution. With the onset of the polymerization, the temperature rose to about 78 °C within about 49 min. A solid polymer gel was obtained.
  • a 1 L glass flask with magnetic stirrer, pH meter and temperature probe was initially charged with 80 g of deionized water, 157.18 g of a 50 wt. % aqueous solution of NaATBS, 3.68 g of a 35 wt. % aqueous solution of NaAA, and 93.53 g of acrylamide (52 % by weight in water).
  • the monomer concentration was adjusted to 43 % by weight relating to the total of all components of the monomer mixture which corresponds to a monomer concentration of 3.43 moles of monomers / kg of the monomer solution.
  • the temperature of the monomer solution was adjusted to the initiation temperature of 0 °C.
  • the solution was transferred to a Dewar vessel, the temperature probe for the temperature recording was inserted, and the flask was purged with nitrogen for 45 minutes.
  • the polymerization was initiated with 2.4 g of a 10 % aqueous solution of the water-soluble azo initiator 2, 2'-Azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride (Wako VA-044), 0.32 g of a 1 wt. % t-BHP solution and 0.64 g of a 1 wt % sodium sulfite solution. With the onset of the polymerization, the temperature rose to about 79 °C within about 22 min. A solid polymer gel was obtained.
  • composition of the polymers in examples 7, 8, and 9 and comparative examples 7, 8, and 9 corresponds to those in examples 1, 2, and 3 and comparative examples 1, 2, and 3, except that additionally a small amount of an associative monomer was used.
  • the effects as shown in figures 5, and 6 are similar to the effects shown in figures 1 and 2.
  • table 1 demonstrates an additional effect, namely that in examples 7, 8, and 9 the viscosity increases significantly from 8.4 mPa*s at a monomer concentration 43 % by wt. to 20.7 mPa*s at a monomer concentration of 31 % by weight. So, the present invention enables manufacturing associative polymers having a higher viscosity.
  • H2C CH-0-CH2CH2CH2CH2-0-(CH2CH20)24.5-(CH2CH(C2H5)0) 16 -(CH2CH 2 0) 3 .5H (0.1 mol % is a rounded number)
  • comparative example 1 a copolymer comprising 50 mole% of acrylamide, 25 mole% of sodium ATBS, and 25 mole% NVP was synthesized.
  • the monomer concentration was 3.07 mole / kg (37 % by weight).
  • Copolymer comprising 49 mole% (28.8 wt. %) of acrylamide, 25.0 mole% (47.4 wt. %) of sodium ATBS, 25.0 mole% NVP (23.0 wt. %), and 1.0 mole% (0.8 wt. %) sodium acrylate
  • Example 1 was repeated, however, the monomer concentration was reduced to 2.57 mole / kg (31 wt. %).
  • the induction time time until temperature rose by 1°C after addition of the initiators was 36 s, T max was 53°C and the time to T max was 22 min.
  • the resultant gel was used for the tests without drying.

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Abstract

L'invention concerne un procédé de production de copolymères hydrosolubles comprenant un méthacrylamide ou un dérivé de celui-ci, l'acide 2-acrylamido-2-méthylpropanesulfonique ou un sel de celui-ci, la N-vinylpyrrolidone et une petite quantité d'un acide carboxylique monoéthyléniquement insaturé hydrosoluble ou d'un sel de celui-ci, de préférence l'acide méthacrylique ou un sel de celui-ci par polymérisation adiabatique conduisant à la formation d'un gel d'une solution aqueuse de monomères, ayant une concentration de monomères de 2 mole/kg à 3,3 mole/kg. L'acide carboxylique monoéthyléniquement insaturé agit comme accélérateur de polymérisation et permet déjà la fabrication de tels monomères contenant N-vinylpyrrolidone à des concentrations de monomères inférieures. L'invention concerne également des polymères hydrosolubles comprenant lesdits monomères et leur utilisation dans la récupération de pétrole brut dans des formations souterraines pétrolifères.
PCT/EP2020/072769 2019-08-26 2020-08-13 Procédé de fabrication de nvp contenant des polyacrylamides WO2021037578A1 (fr)

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WO2022106308A1 (fr) 2020-11-23 2022-05-27 Basf Se Procédé de fabrication de copolymères contenant de la nvp hydrosolubles sous forme de poudre

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