DESC:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

Title of invention:
ACRYLAMIDO TERTIARY BUTYL SULFONIC ACID, MONOMER, POLYMER AND PREPARATION PROCESS THEROF

APPLICANT:
VINATI ORGANICS LIMITED
An Indian company having address as:
Parinee Crescenzo, A Wing, 11th floor, 1102, G Block, Behind MCA, Bandra Kurla Complex, Bandra (east), Mumbai 400051, Maharashtra, India

The following specification particularly describes the invention and the manner in which it is to be performed.

CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY
The present application claims priority from IN Provisional Patent Application No. 202321012905 filed on February 25, 2023.
TECHNICAL FIELD
The present subject matter, in general, relates to the field of process chemistry. More particularly, the present subject matter relates to ATBS and process for synthesizing the same.
BACKGROUND
Acrylamide tertiary butyl sulfonic acid (hereinafter referred to as “ATBS” or “AMPS”) is a versatile and unique alkyl acrylamide monomer comprising of an attached sulfonic acid group. ATBS has wide applications as a modifier for acrylic fibre, a monomer raw material for dispersing agent or coagulating agent, a monomer raw material for thickening agent of cosmetic, as well as a monomer raw material for producing polymers/copolymers used in high order/enhanced recovery of crude oil (EOR).
EOR is a thermal or compositional transformation of either the hydrocarbons or reservoir rock to aid in the recovery of additional volumes of oil, which is presently recognized as the world’s primary energy source.
EOR helps to maximize the oil reserves recovered, extend the life of fields, and increase the recovery factor. At present, EOR has emerged as an essential technique in global oil production, due to the decline in the production from mature fields, and insufficiency in the discovery of new hydrocarbon reserves, to match the growing energy demand.
Nonthermal/chemical EOR methods involving polymers/ copolymer of acrylamide tertiary butyl sulfonic acid (ATBS) monomers are known to have an overwhelming demand in adverse offshore enhanced oil recovery (EOR) applications, which involve tremendously high polymer/copolymer residence time, and requisite long-term polymer/ copolymer stability within anaerobic reservoirs at high temperature, and saline conditions, and are also known to be financially sustainable. They are therefore recognized to be one of the most promising methods for recovering heavy oil in recent years.
It is known that viscosity of ATBS polymers/copolymers is crucial for mobility control ability. Highly viscous ATBS polymers/copolymers increase the viscosity of water phase and reduce the water-oil mobility ratio, thereby improving sweep efficiency, and escalating the EOR.
It is also known that the physical properties of dispersed monomers, including the monomeric size distribution, and average monomeric particle/particulate size affect the overall ATBS polymer/copolymer characteristics, such as their viscosity.
Decrease in monomeric particle size increases the number of monomeric particles in the case of a constant volume fraction. This, in turn, increases the degree of interactions between the monomeric particles, especially in the case of sub-micron sized monomeric particles. The surface charge, hydration or adsorption layers surrounding these monomeric particles substantially increase their effective hydrodynamic size. The impact of increasing the number of particles present is magnified by these layers. This, in turn, increases the suspension viscosity by increasing the effective volume fraction for a specific particle loading. Furthermore, it is known that more free space is available in the case of wide distribution and higher polydispersibility for individual particles to move around. As a result, the sample flows easily, lowering the viscosity.
Thus, there is a long-felt need to synthesize ATBS having lower average particulate size, and narrower particulate size distribution, and achieving lower polydispersibility index.
SUMMARY
An embodiment of the present disclosure relates to acrylamide tertiary butyl sulfonic acid (ATBS) comprising particulates characterized in that, d10 of said particulates ranges from 1.2 µm to 2.1 µm; d50 of said particulates ranges from 11 µm to 16 µm; and d90 of said particulates ranges from 61 µm to 70 µm.
Another embodiment of the present disclosure relates to a process for synthesizing ATBS comprising, preparing a sulfonating mixture; reacting said sulfonating mixture with acrylonitrile (ACRN) to obtain ACRN-sulphate; reacting said ACRN-sulphate with isobutylene (IB) to obtain ATBS slurry; and purifying said ATBS slurry to obtain said ATBS comprising particulates characterized in that, d10 of said particulates ranges from 1.2 µm to 2.1 µm; d50 of said particulates ranges from 11 µm to 16 µm; and d90 of said particulates ranges from 61 µm to 70 µm.
This summary is not intended to identify all the essential features of the claimed subject matter, nor is it intended to be used in determining or limiting the scope of the claimed subject matter.
BRIEF DESCRIPTION OF DRAWINGS
The detailed description of drawings is outlined with reference to the accompanying figures. In the figures, the left-most digit (s) of a reference number identifies the Figure in which the reference number first appears. The same numbers are used throughout the drawings to refer like features and components.
Fig. 1 illustrates a process flow diagram (PFD) for synthesizing ATBS.
Fig. 2 demonstrates XRD study of Grade 1 ATBS.
Fig. 3 demonstrates XRD study of Grade 2 ATBS.
Fig. 4 demonstrates ATBS particulate size distribution study (volume statistics – arithmetic) for Grade 1 ATBS.
Fig. 5 demonstrates ATBS particulate size distribution study (volume statistics – arithmetic) for Grade 2 ATBS.
Fig. 6 demonstrates an overlay of ATBS particulate size distribution studies for Grade 1 ATBS, and Grade 2 ATBS.
Fig. 7 demonstrates viscosity measurement – Effect of hydrogen concentration on viscosity at constant temperature wherein, Viscosity ? is measured as a function of shear rate (???) for several different concentrations of ATBS hydrogels at 25°C.
Figs. 8(A-C) demonstrate viscosity measurement – Effect of temperature on viscosity at varying ATBS hydrogel concentrations wherein, viscosity ? of different concentrations of ATBS hydrogel is measured as a function of shear rate (???) at several different temperatures.
Figs. 9(A-C) demonstrate viscosity measurement – Effect of salt on viscosity at varying ATBS hydrogel concentrations wherein, viscosity ? of different concentrations of ATBS hydrogel is measured as a function of shear rate (???) with 1000 ppm of NaCl salt at 25°C.
Fig. 10 demonstrates effect of ATBS hydrogel concentration on yield stress and strain.
Figs. 11(A-C) demonstrate effect of temperature on yield stress and strain at varying ATBS hydrogel concentrations.
Figs. 12(A-C) demonstrate effect of salt on yield stress and strain at varying ATBS hydrogel concentrations.
Fig. 13 demonstrates effect of ATBS hydrogel concentration on relaxation time scales.
Figs. 14(A-C) demonstrates effect of temperature on relaxation time scales at varying ATBS hydrogel concentrations.
Fig. 15 demonstrates effect of salt on relaxation time scales at constant ATBS hydrogel concentration.
DETAILED DESCRIPTION
Reference throughout the specification to “various embodiments,” “some embodiments,” “one embodiment,” “alternate embodiment”, or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in various embodiments,” “in some embodiments,” “in one embodiment,” or “in an embodiment”, “in an alternate embodiment”, or “in a related embodiment” in places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.
Reference throughout the specification to “components”, “component”, “features”, or “feature” means a constituent or group of constituents embodying the process. Further, for the purpose of instant disclosure, the term “about” pertains to ± 0.1-2 units, as is perceivable to a person skilled in the art. In addition to this, for the purpose of instant disclosure, the term “specific” pertains to, as per requirements, or as is perceivable to a person skilled in the art, until explicitly stated.
Before the present process is described, it is to be understood that this disclosure is not limited to the particular process as described, as there can be multiple possible embodiments which are not expressly illustrated in the present disclosure but may still be practicable within the scope of the present disclosure.
Also, the technical solutions offered by the present disclosure are clearly and completely described below. Examples in which specific conditions may not have been specified, have been conducted under conventional conditions or in a manner recommended by the manufacturer.
Instant disclosure relates to the field of process chemistry; and particularly relates to ATBS and process for synthesizing the same.
First aspect of the instant disclosure relates to a process for synthesizing ATBS comprising, preparing a sulfonating mixture; reacting said sulfonating mixture with ACRN to obtain ACRN-sulphate; reacting said ACRN-sulphate with IB to obtain ATBS slurry; and purifying said ATBS slurry to obtain said ATBS comprising particulates characterized in that, d10 of said particulates ranges from 1.2 µm to 2.1 µm; d50 of said particulates ranges from 11 µm to 16 µm; and d90 of said particulates ranges from 61 µm to 70 µm.
For the purpose of instant disclosure and as is perceivable to a person skilled in the art, the term “particulate” or “particulates” pertains to particles, particle, or a minute portion of matter, as is perceivable to a person skilled in the art and is fundamentally known. Further, the term “acrylamide tertiary butyl sulphonic acid” OR “ATBS” pertains to ATBS monomer. In addition to this, the terms, d10, d50, and d90 pertain to particulate size corresponding to the cumulative frequency of 10%, 50%, and 90%, respectively, as is perceivable to a person skilled in the art.
A particular embodiment relates to a process for synthesizing ATBS.
One embodiment relates to preparing a sulfonating mixture.
For the purpose of instant disclosure and as is perceivable to a person skilled in the art, the term “sulfonating mixture” pertains to a process that involves the implementation of sulphuric acid (H2SO4) and oleum.
In one embodiment, sulfonating mixture is prepared using at least one of 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 99.99% of H2SO4; and preferably, 95% to 99% of H2SO4.
In another embodiment, sulfonating mixture is prepared using oleum; preferably, at least one of 10% - 50% oleum; and particularly, at least 20% - 40% oleum.
In a related embodiment, preparation of sulfonating mixture is carried out in a reactor.
For the purpose of this disclosure and as is perceivable to a person skilled in the art, the term “reactor”, “fermenter”, or “vessel” pertains to generator, jar, tank, or any manufactured device or system that supports a chemical environment. In a further embodiment, the “reactor” is rectangular, cylindrical, or circular shaped; and preferably, cylindrical shaped. Furthermore, in a related embodiment, the “reactor” is horizontally, diagonally, or vertically angled.
In another embodiment, the “reactor” is a small, medium, or large capacity “reactor”. Furthermore, in a related embodiment, volume of “reactor” is any volume from 1 litre to several thousands of litres, as per requirements. In addition to this, the reactor is any fed-batch, batch, static and/or continuous reactor.
In an embodiment, the reactor is a static batch reactor.
In a related embodiment, pre-determined quantities of H2SO4 (as per requirements) is transferred to a reactor; and preferably, circulated using any conventionally known circulating means; and particularly via one or more centrifugal pump(s) to which was added oleum.
In another related embodiment, preparation of sulfonating mixture is carried out for about 0.5 to 7 h; and preferably, for about 1 to 5 h.
In a further related embodiment, uniform mixing is implemented; preferably, such that the mixing ratio typically ranges from about 0.12 to 0.20: 1.
In an embodiment, sulfonating mixture is obtained, which is then transferred to a storage tank.
For the purpose of instant disclosure and as is perceivable to a person skilled in the art, the term “storage tank” pertains to a vessel as is described above, for storing chemicals, as is perceivable to a person skilled in the art in the instant case.
Another embodiment of the instant disclosure relates to preparation of ACRN-sulphate.
In an embodiment, ACRN is added; and preferably pumped in a reactor, as is described above; and particularly, in a continuous flow reactor.
In a related embodiment, the flow rate of ACRN ranges from 1000 kg/h to 9000 kg/h.
In another related embodiment, ACRN is chilled using conventionally known cooling means; preferably, to maintain temperature between about -15°C to -5°C.
In another embodiment, the sulfonating mixture is added to the reactor; preferably, in a 100 kg/h to 1000 kg/h.
In a related embodiment, the sulfonating mixture is added via one or more inlet(s); and particularly, one or more sparger(s); preferably positioned at top, bottom, or side of the reactor; and particularly, at the top of the reactor.
For the purpose of instant disclosure and as is perceivable to a person skilled in the art, the term “one or more” pertains to one or more than one.
In a further embodiment, the reactor preferably comprises an agitator system.
For the purpose of instant disclosure and as is perceivable to a person skilled in the art, the term “agitator system” pertains to a device or mechanism to put something into motion by shaking or stirring, and comprises one or more of mechanical, automated, or magnetic agitators, preferably comprising of more or more shafts, propellers and/or impellers, and may come in different sizes, and shapes, as are perceivable to a person skilled in the art.
In a related embodiment, the agitation system facilitates mixing of the sulphonating mixture and the ACRN via one or more pairs of propellers; preferably, rotating at a speed of about 100 rpm -110 rpm; and particularly rotating at a tip speed of about 4.21 - 4.63 m/s.
In a particular embodiment, ACRN-sulphate is obtained.
In a related embodiment, excess heat is removed by conventionally known methods, and preferably, using one or more heat exchangers that are perceivable to a person skilled in the art.
In yet another related embodiment, the ACRN-sulphate obtained as a result is either stored, transferred, or implemented for further processing.
Yet another embodiment relates to reacting ACRN-sulphate with isobutylene (IB); preferably in a different/separate reactor described above; particularly to obtain ATBS slurry.
For the purpose of instant disclosure and as is perceivable to a person skilled in the art, the term “slurry” refers to crude and unpurified form of compound (in this case, ATBS).
In an embodiment, ACRN :IB (i.e., ratio of ACRN to IB) is at least one of about 5-20:0.1-2; and preferably, either about 10-12:1 or about 13-17:1; and particularly, either about 11:1 or about 15:1.
In another embodiment, % of ATBS slurry obtained ranges about 1% - 20%; and preferably, is either about 19% ± 1% or about 16% ± 1%.
In one embodiment, the acid number of the ATBS synthesis reaction mixture forming the ATBS slurry is consistently maintained within the range of 30-40, and preferably within the range of 35-37.
A further embodiment of the instant disclosure relates to purifying ATBS slurry.
In an embodiment, purification of ATBS slurry is carried out using conventionally known purification/purifying methods, preferably, using either a belt filter or a rotary pressure filter; and particularly, using a rotary pressure filter.
In a related embodiment, feed of ATBS slurry ranges from about 1 kg/h to thousands of kg/h; and preferably ranges from 9000-9500 kg/h.
In another related embodiment, ATBS slurry is washed; and particularly using a washing liquid such as ACRN.
In a further related embodiment, ratio of the ATBS slurry to washing liquid ranges from 0.1-10; and particularly ranges from 1:2-7.
In an embodiment, ratio of the ATBS slurry to washing liquid is about 1:2-3
In another embodiment, ratio of the ATBS slurry to washing liquid is about 1:6-7.
In a further embodiment, the washing liquid is supplied via an inlet; and particularly, via a nozzle as described above.
In an embodiment, ATBS wet cake is obtained.
In an embodiment, a conventionally known inert gas is implemented/applied to the filter described above.
In an exemplary embodiment, the inert gas is nitrogen (N2), particularly applied at a pressure of about 2.5-3 kg/cm3.
In yet another embodiment, the rotary pressure filter is at least one of continuous, or semi-continuous, and/or automated, manual and/or semi-automated; and preferably, continuous and automated.
In a further embodiment, the rotary pressure filter is automated using at least one of electrical, magnetic or other conventionally known power supply means.
In an embodiment, the rotary pressure filter is rotated by means of an electrical motor; preferably, further comprising a rotating shaft; particularly rotating at a speed of about 50-55 RPH.
In another embodiment, the pressure in the continuous rotary pressure filter is maintained; and preferably, between about 2.5 kg/cm2 to 3 kg/cm2.
In a further embodiment, the ATBS wet cake is occasionally or continuously; and preferably, continuously scrapped, preferably, using a conventionally known scrapper.
In yet another further embodiment, the ATBS wet cake is stored.
In an alternate embodiment, the ATBS wet cake is dried to obtain ATBS, and preferably, characterized.
In an embodiment, predetermined weight of ATBS slurry is fed to rotary pressure filter at a rate of about 9000-9500 kg/h. Then said ATBS slurry is washed using a washing liquid such as ACRN in a ratio ranging from 1:2-7 supplied through a nozzle (from a washing liquid storage tank) to obtain ATBS wet cake. Then, optionally an inert gas such as N2 is continuously applied to said filter at a pressure of about 2.5-3 kg/cm3. The continuous rotary pressure filter is rotated by means of an electrical motor, wherein the said electric motor further comprises a rotating shaft which is rotated at a speed of about 50-55 RPH. The pressure in the continuous rotary pressure filter is maintained between about 2.5 kg/cm2 to 3 kg/cm2. The ATBS wet cake obtained as a result is continuously scrapped using a scrapper and fed to a rotary vacuum paddle. The ATBS wet cake is either stored, or alternatively dried to obtain ATBS.
In a related embodiment, the washing liquid is separated; and preferably, recovered for further use.
The ATBS synthesized as per above process may be present in any of the conventionally known forms such as powder, granule(s), flake(s), etc.
In one embodiment, ATBS powder/ ATBS monomer powder is obtained using conventionally known mixers or grinders.
In another embodiment, ATBS monomer granules are prepared; preferably, using a granulation unit comprising compactor, granulator and sifter, optionally a powder transfer system for recycling uncompacted ATBS powder back to the compactor.
For the purpose of instant disclosure and as is fundamentally known to a person skilled in the art, the term “ATBS monomer granules” or “ATBS monomer granule” pertains to compacted aggregates or particles of ATBS described above.
In a related embodiment, sizes of ATBS monomer granules are pre-determined as per requirements.
In another related embodiment, the sizes of ATBS monomer granules range from 0.2 mm to 8 mm; and preferably from 0.8 mm to 5 mm.
The process is either manual, automated, or semi-automated; and preferably, the whole process is monitored and controlled by implementing a conventionally known optimized distributed control system (DCS system).
In an embodiment, the ATBS demonstrates purity.
It is known that 2-methylidene-1,3-propylenedisulfonic acid (IBDSA), and 2-methyl-2-propenyl-1-sulfonic acid (IBSA) are conventionally known impurities in ATBS production.
In one embodiment, the concentration of IBDSA is low; preferably, ranging from 0-500 ppm.
In a related embodiment, the concentration of IBDSA is 0 to = 110.
In another related embodiment, the concentration of IBDSA is = 110 to = 200.
In another embodiment, the concentration of IBSA is low; preferably, ranging from 0-500 ppm.
In a related embodiment, the concentration of IBSA is 0 to = 200.
In another related embodiment, the concentration of IBDSA is = 200 to = 350.
In one embodiment, the ATBS is characterized/analysed.
It is known that XRD generates real signature, which is specific to each organic or inorganic compound, and presents in the form of a list of peaks with positions at the 2-theta angle (2-?). This technique is fundamentally used to characterize the material.
In an embodiment, XRD studies are carried out over an angular range of about 5° to 60°.
In a related embodiment, ATBS shows X-ray diffraction (XRD) pattern with following characteristics peaks at 2-? degrees (+/-0.1°):
11.52°, 13.07°, 15.37°, 19.32°, 19.78°, 22.03°, 22.74°, 23.23°, 24.03°, 24.77°, 25.12°, 26.31°, 27.42°, 29.27°, 31.23°, 32.62°, 33.98°, 34.60°, 25.13°, 35.72°, 37.40°, 37.72°, 38.74°, 39.88°, 46.82°, 48.33°.
In another related embodiment, ATBS has a 2-? X-ray diffraction pattern with following characteristics peaks 2-? degrees (+/-0.1°):
11.60°, 13.11°, 15.42°, 19.36°, 19.81°, 22.05°, 22.78°, 23.26°,25.16, 26.31°, 27.45°, 31.25°, 33.99°, 34.61°, 35.13°,35.68°, 37.38°, 37.69°, 38.85°, 39.93°, 46.76°, 48.28°.
In another embodiment of the instant disclosure, acid function of ATBS is determined.
In a related embodiment, predetermined quantity of ATBS and demineralized water is added in a beaker.
In another related embodiment, predetermined concentration of sodium hydroxide (NaOH) is added dropwise as is conventionally known; preferably, using graduated burette; and particularly, until initial pH of about 0.28 increases to the equivalence point of about pH 7.0.
In an exemplary embodiment, to about 50g of ATBS, about 250 ml of demineralized water is added and which is titrated with dropwise addition of about 30% NaOH solution. The titration is monitored using a pH meter until the initial pH of about 0.28 increased to the equivalence point of about pH 7.0.
In a related embodiment, the acid function of ATBS is about = 99%.
In one embodiment, the acid function of ATBS is about = 99.5%.
In another embodiment, the acid function of ATBS is about = 99.0% but = 99.4%.
It is known that SEM analysis uses a focused beam of electrons to produce complex, high magnification images of a sample's surface topography, where only milligram quantities of material may be used to determine particulate size, shape, and texture.
In an embodiment, SEM analysis of ATBS is carried out.
In one embodiment, average particulate size of ATBS is = 0.4 µm.
In one exemplary embodiment, ATBS shows an average particulate size of about 0.2552 µm; preferably, an average standard deviation of about 0.121319326 µm; and coefficient of variation (cv) of about 47.53%.
In another exemplary embodiment, ATBS shows an average particulate size of about 0.33125 µm; preferably, an average standard deviation of about 0.125689205 µm; and coefficient of variation (CV) of about 37.94391102%.
Yet another embodiment of the instant disclosure relates to determination of ATBS particulate size distribution; preferably using conventionally known methods; and particularly using Bechman Coulter LS particle size analyser as is known to a person skilled in the art.
An embodiment of the instant disclosure relates to acrylamide tertiary butyl sulfonic acid (ATBS) comprising particulates characterized in that, d10 of said particulates ranges from 1.2 µm to 2.1 µm; d50 of said particulates ranges from 11 µm to 16 µm; and d90 of the particulates ranges from 61 µm to 70 µm.
In one embodiment, volume statistics (arithmetic) for ATBS (calculations from 0.375 µm to 2000 µm) is about Volume – 100%, mean – about 21.38 µm, D(3,2) – about 4.193 µm, standard deviation (SD) – 23.80 µm, CV – 111%, and specific surface area – 1.431 m3/mL.
In an embodiment, d10 of ATBS particulates ranges from 1.3 µm to 1.4 µm; d50 of said particulates ranges from 11.5 µm to 11.7 µm; and d90 of the particulates ranges from 61.8 µm to 70.0 µm.
In a related embodiment, d10 of ATBS particulates is about 1.391 µm.
In another related embodiment, d50 of ATBS particulates is about 11.63 µm.
In a further related embodiment, d90 of ATBS particulates is about 61.94 µm.
In another embodiment, volume statistics (arithmetic) for ATBS (calculations from 0.375 µm to 2000 µm) is about Volume – 100%, Mean – about 25.61 µm, D(3,2) – about 5.117 µm, standard deviation (SD) – 26.59 µm, CV – 104%, and specific surface area – 1.173 m3/mL.
In an exemplary embodiment, d10 of ATBS particulates ranges from 1.9 µm to 2.2 µm; d50 of said particulates ranges from 15.0 µm to 15.4 µm; and d90 of the particulates ranges from 69.5 µm to 69.9 µm.
In a related embodiment, d10 of ATBS particulates is about 2.061 µm.
In another related embodiment, d50 of ATBS particulates is about 15.23 µm.
In a further related embodiment, d90 of ATBS particulates is about 69.75 µm.
A further embodiment of the instant disclosure relates to studying viscosity of ATBS.
In a related embodiment, ATBS homopolymer is prepared for studying viscosity of ATBS.
In another related embodiment, ATBS homopolymer is prepared by dissolving specific wt% of ATBS in demineralized water in a specific ratio.
In yet another related embodiment, viscosity is analysed using conventionally known methods, such as Digital Brookfield Viscometer at specific temperature and rpm as per requirements.
In a particular embodiment, homo-polymerization of ATBS yields polymer having viscosity of = 10000 cps; preferably, ranging from 10000-12000 cps.
In one embodiment, homo-polymerization of ATBS yields polymer having viscosity of about 12000 cps.
In another embodiment, homo-polymerization of ATBS yields polymer having viscosity of about 10560 cps.
In an embodiment, particulates of ATBS have lower average particulate size.
In another embodiment, particulates of ATBS have narrower particulate size distribution.
In yet another embodiment, particulates of ATBS are more viscous.
A further embodiment relates to synthesis of ATBS polymer / copolymer with acrylamide i.e. (poly (2-acrylamido-3-methylpropanesulfonate-coacrylamide).
For the purpose of instant disclosure and as is perceivable to a person skilled in the art, the term “polymer/copolymer” pertain to compound composed as a result of chemical bonding/interactions between ATBS monomer described above, and may be present in any one of the conventionally known forms.
In a related embodiment, predetermined quantity of ATBS is dissolved in predetermined quantity of water.
In another related embodiment, pH is adjusted by conventionally known pH adjusting means, and preferably, using NaOH.
In a further related embodiment, predetermined quantity of acrylamide is added.
Process parameters are maintained as per requirements, and as are perceivable to a person skilled in the art.
In an embodiment, the process is controlled at a temperature ranging from 20°C to 50°C; and preferably, from 25°C to 40°C.
In another embodiment, inert gas, and preferably, N2 is purged.
Further embodiment relates to addition of one or more of copper chloride, ammonium persulfate, sodium sulfite, and radical polymerization initiator.
Yet another further embodiment relates to carrying out the polymerization reaction for about = 3h; and preferably, for about 2 h.
In an embodiment, ATBS polymer/copolymer is obtained.
In one embodiment, about 40 g of ATBS is dissolved in about 60 g of water. Then about 48 wt. % aqueous NaOH solution is added for adjusting the pH around 8. The concentration of ATBS is adjusted with water to about 35 wt.%. Then about 55.6 g of about 40 wt.% aqueous acrylamide solution is added, followed by addition of about 5.2 g of water to adjust the concentration of monomers to about 35 wt.%. The solution temperature is controlled at about 30°C, and purged with N2. Then, about 0.7 g of ammonium persulfate, about 0.7 g of sodium sulfite, about 0.6 g of aqueous copper chloride solution containing about 10 mass ppm of copper ion, and about 0.7 g of an aqueous solution containing about 10 wt. % of V-50 as a diazo type of radical polymerization initiator is added to the solution. The reaction is carried out for about 2 h to obtain ATBS polymer/copolymer.
In a related embodiment, the ATBS polymer/copolymer has lower polydispersibility index.
For the purpose of instant disclosure and as is perceivable to a person skilled in the art, “polydispersibility index”, “PI”, “PDI”, or “heterogeneity index” is a measure of the heterogeneity of a sample based on size.
In an embodiment, polydispersibility index (PI) of ATBS polymer/copolymer is within the range of 1-2.
In one embodiment, PI of ATBS polymer/copolymer is about 1.497.
In another embodiment, PI of ATBS polymer/copolymer is about 1.432.
In another related embodiment, the ATBS polymer/copolymer has high polymer viscosity.
In one embodiment, polymer viscosity of ATBS polymer/copolymer is about 28.3 cps.
In another embodiment, polymer viscosity of ATBS polymer/copolymer is about 23.7 cps.
In yet another related embodiment, the ATBS polymer/copolymer has high polymer salt viscosity.
It is known that highly viscous polymers/copolymers increase the viscosity of water phase and reduce the water-oil mobility ratio, thereby improving sweep efficiency, and escalating the EOR.
In one embodiment, salt viscosities of ATBS polymer/copolymer at 150 rpm, and 200 rpm were about 17.9 cps, and about 22.4 cps.
In another embodiment, salt viscosities of ATBS polymer/copolymer at 150 rpm, and 200 rpm were about 17.1 cps, and about 20.4cps.
In an exemplary embodiment, the ATBS of the instant disclosure may be feasibly implemented for achieving EOR.
Yet another further embodiment relates to synthesis of ATBS polymer/copolymer hydrogel(s).
For the purpose of instant disclosure and as is perceivable to a person skilled in the art, the term “hydrogel”, “aqueous solution”, “hydrogels”, “ATBS hydrogel”, or “ATBS hydrogels” pertain to aqueous solutions prepared using ATBS polymer/copolymer.
In an exemplary embodiment, ATBS polymer/copolymer, particularly in powder form is implemented and preheated; preferably, at about 100°C for about 1 h to obtain hydrogel.
In a related embodiment, conventionally known rheological studies of the hydrogel are performed, particularly with respect to the implementation of said hydrogel in EOR.
It is known that high viscosity improves sweep efficiency, and escalates the EOR. Further, it is also known that effect of temperature and salt on the rheological properties of sample compound (i.e., the hydrogel in the present case) plays a pivotal role in determining the efficiency of said compound in EOR.
In one embodiment, viscosity measurement is performed.
In a related embodiment, at a fixed temperature, viscosity of aqueous solution of ATBS polymer (hydrogel) increased with the increase in the concentration of ATBS polymer/copolymer in water.
In another related embodiment, strength of ATBS hydrogel at a concentration above about 0.5 % w/w is unaffected by temperature.
In yet another related embodiment, strength of ATBS hydrogel at a concentration of about 1.0 % w/w is unaffected in the presence of about 1000 ppm of NaCl.
In another embodiment, amplitude sweep experiment is performed.
In a related embodiment, yield strain and yield stress values of the ATBS hydrogel increases with the increase in concentration of ATBS polymer/copolymer (in ATBS hydrogel).
In another related embodiment, strength, and structure of the ATBS hydrogel are not affected by the solvent temperature for concentrations above about 0.5 % w/w.
In further related embodiment, the effect of an increase in salt concentration on the strength and structure of the ATBS hydrogel reduces with the increase in the concentration of ATBS polymer/copolymer (in ATBS hydrogel).
In yet another embodiment, frequency sweep experiment is performed.
In a related embodiment, the disentanglement of ATBS polymer/copolymer in ATBS hydrogel takes a long time with the increase in ATBS polymer concentration in an aqueous solution (ATBS hydrogel).
In another related embodiment, there is an absence of faster relaxation time scales in the ATBS hydrogel at a higher temperature.
In further embodiment, there is an absence of slower relaxation time scales in the ATBS hydrogel in the presence of salt.
In an embodiment, the rheological studies of the ATBS hydrogel may help in optimizing process parameters, as is perceivable to a person skilled in the art.
In an exemplary embodiment, the rheological studies of the ATBS hydrogel may help in identifying appropriate concentration of ATBS hydrogel to be implemented as per the process parameters/conditions to facilitate, particularly, feasible and elevated EOR.
Various modifications to the embodiment will be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments. However, one of ordinary skill in the art will readily recognize that the present disclosure is not intended to be limited to the embodiments illustrated but is to be accorded the widest scope consistent with the principles and features described herein.
The foregoing description shall be interpreted as illustrative and not in any limiting sense. A person of ordinary skill in the art would understand that certain modifications could come within the scope of this disclosure. The features and properties of the present disclosure are described in further detail below with reference to examples.
Example 1
Process for synthesizing ATBS (see Fig. 1) and characterization thereof (see Figs. 2-6)
Preparation of sulfonating mixture
First a batch quantity of about 98% H2SO4 was transferred to a static batch reactor and circulated in said reactor via a centrifugal pump. Then controlled addition of about 30% oleum (in said reactor comprising about 98% H2SO4) was initiated. Said addition was carried out for about 1.5 h to 3 h. Uniform mixing was carried out to obtain a concentrated sulfonating mixture. Mixing ratio was typically within the range of about 0.12 to 0.20:1.
The sulfonating mixture obtained as a result was then transferred to a storage tank for further processing.
Preparation of ACRN-sulphate
First ACRN was pumped in a continuous flow reactor (equipped with an agitator system) at a flow rate ranging from 1000 kg/h to 9000 kg/h and chilled using conventionally known chilling means for maintaining the temperature between about -15°C to -5°C. Then, controlled addition of sulfonating mixture from storage tank was initiated in said reactor via a sparger positioned at the top of the said reactor for about 30 mins to 60 mins.
The agitation system facilitated the mixing of the sulphonating mixture and the ACRN via one or more pairs of propellers rotating at a speed of about 100 rpm -110 rpm and a tip speed of about 4.21-4.63 m/s to obtain ACRN-sulphate.
Excess heat of mixing was removed by means of a conventionally known cooling means such as heat exchangers.
ACRN-sulphate obtained as a result was transferred to another reactor for further processing.
Preparation of ATBS slurry
The ACRN-sulphate was reacted with IB in a different reactor to obtain ATBS slurry which was further purified using either a belt filter or a rotary pressure filter.
Following ratios of ACRN with IB were considered to perform the above-described experiment.
a) ACRN: IB was about 10-12: 1
b) ACRN: IB was about 13-17: 1
About 15% - 25% of ATBS slurry was achieved.
Table 1: % of ATBS slurry achieved through ACRN:IB ratios
Ratio of ACRN Ratio of IB % of ATBS slurry achieved Grades
10-12 1 19% ± 1% Grade 1
13-17 1 16% ± 1% Grade 2
For the purpose of instant disclosure and as is perceivable to a person skilled in the art, the term “Grade” or “Grades” indicates a particularly distinct quality of ATBS slurry and/or ATBS, as is described in the present case.
Purification using rotary pressure filter to obtain ATBS
Predetermined weight of ATBS slurries (see Table 1) were fed to said filter at a rate of about 9000-9500 kg/h. Then said ATBS slurry was washed using a washing liquid such as ACRN at a ratio ranging from 1:2-7 supplied through a nozzle (from a washing liquid storage tank) to obtain ATBS wet cake (see Table 2).
[Table 2]
Ratio of ATBS slurry to washing liquid
Grade 1 ATBS slurry 1:2-3
Grade 2 ATBS slurry 1: 6-7

Optionally, an inert gas such as N2 was continuously applied to said filter at a pressure of about 2.5-3 kg/cm3. The rotary pressure filter was continuously rotated by means of an electrical motor, wherein the said electric motor further comprised a rotating shaft which rotated at a speed of about 50-55 RPH. The pressure in the continuous rotary pressure filter was maintained between about 2.5 kg/cm2 to 3 kg/cm2. The ATBS wet cake obtained as a result was continuously scrapped using a scrapper and fed to a rotary vacuum paddle. The ATBS wet cake was either stored, or alternatively dried to obtain two different grades of dried ATBS – Grade 1 ATBS, and Grade 2 ATBS.
The washing liquid was separated and recovered for further use.
The whole process was monitored and controlled by implementing an optimized distributed control system (DCS system).
Purity analysis
Capillary electrophoresis (CE) was carried out to undertake a comparative study of Grade 1 ATBS, and Grade 2 ATBS of the instant invention with commercially available ATBS (sample) by analysing IBDSA, and IBSA concentrations (see Table 3)
[Table 3]
Commercially available ATBS Grade 1 ATBS of instant invention Grade 2 ATBS of instant invention
IBDSA concentration (ppm) [201-300] [0-110] [110-200]
IBSA concentration (ppm) [350-500] [0-200] [200-350]
Note: IBDSA and IBSA are conventionally known impurities in ATBS production.
As per Table 3, Grade 1 ATBS, and Grade 2 ATBS of the instant disclosure demonstrate better purity compared to commercially available ATBS.
Grade 1 ATBS and Grade 2 ATBS were then further characterized.
Characterization of ATBS
X-ray diffraction (XRD) studies of ATBS
It is known that XRD generates real signature, which is specific to each organic or inorganic compound, and presents in the form of a list of peaks with positions at the 2-theta angle (2-?) which is fundamentally used to characterize the material.
Grade 1, and Grade 2 ATBS obtained previously were analysed by XRD over an angular range of about 5° to 60°.
As per Fig. 2, Grade 1 ATBS had a 2-? X-ray diffraction pattern with following characteristics peaks 2-? degrees (+/-0.1°):
11.52°, 13.07°, 15.37°, 19.32°, 19.78°, 22.03°, 22.74°, 23.23°, 24.03°, 24.77°, 25.12°, 26.31°, 27.42°, 29.27°, 31.23°, 32.62°, 33.98°, 34.60°, 25.13°, 35.72°, 37.40°, 37.72°, 38.74°, 39.88°, 46.82°, 48.33°.
Further, as per Fig. 3, Grade 2 ATBS had a 2-? X-ray diffraction pattern with following characteristics peaks 2-? degrees (+/-0.1°):
11.60°, 13.11°, 15.42°, 19.36°, 19.81°, 22.05°, 22.78°, 23.26°,25.16, 26.31°, 27.45°, 31.25°, 33.99°, 34.61°, 35.13°,35.68°, 37.38°, 37.69°, 38.85°, 39.93°, 46.76°, 48.28°.
Determination of acid function of ATBS
To a 100 mL beaker equipped with a magnetic needle, was added about 50 g of ATBS (Grade 1, and Grade 2, independently) and about 250 ml of demineralized water followed by a dropwise addition of about 30% NaOH. The titration was monitored using a pH meter until the initial pH of about 0.28 increased to the equivalence point of about pH 7.0. Thus, it was determined that about 32.05 g of about 30 % sodium hydroxide was required.
It was reported that the acid function of Grade 1 ATBS is about = 99.5%, whereas that of Grade 2 ATBS is about = 99.0% but = 99.4%.
Scanning electron microscopy (SEM) analysis
It is known that SEM analysis uses a focused beam of electrons to produce complex, high magnification images of a sample’s surface topography, where only milligram quantities of material may be used to determine particulate size, shape, and texture.
As per SEM analysis/images, Grade 1 ATBS showed an average particulate size of about 0.2552 µm, an average standard deviation of about 0.121319326 µm, and coefficient of variation (CV) of about 47.53%.
Further, Grade 2 ATBS showed an average particulate size of about 0.33125 µm, an average standard deviation of about 0.125689205 µm, and coefficient of variation (CV) of about 37.94391102%.
ATBS Particulate size distribution
ATBS Particulate size distribution was determined using Bechman Coulter LS particle size analyser as per conventionally known methods.
Volume statistics (arithmetic) for Grade 1 ATBS (calculated from 0.375 µm to 2000 µm): Volume – 100%, Mean – about 21.38 µm, D(3,2) – about 4.193 µm, standard deviation (SD) – 23.80 µm, CV – 111%, and specific surface area – 1.431 m3/mL. As per Fig. 4, d10, d50, and d90 of Grade 1 ATBS particulates were about 1.391 µm, 11.63 µm, and 61.94 µm, respectively.
Volume statistics (arithmetic) for Grade 2 ATBS (calculated from 0.375 µm to 2000 µm): Volume – 100%, Mean – about 25.61 µm, D(3,2) – about 5.117 µm, standard deviation (SD) – 26.59 µm, CV – 104%, and specific surface area – 1.173 m3/mL. As per Fig. 5, d10, d50, and d90 of Grade 2 ATBS particulates were about 2.061 µm, 15.23 µm, and 69.75 µm, respectively.
In addition to this, Fig. 6 illustrates an overlay of size distribution studies for ATBS particulates of Grades 1, and 2.
Viscosity studies of ATBS homopolymers
Grade 1 and Grade 2 ATBS homopolymers were prepared by dissolving specific wt % of Grade 1, and 2 ATBS in demineralized water in a specific ratio. Viscosity was analysed at about 25°C using conventionally known methods such as, Digital Brookfield Viscometer at about 60 rpm.
Separate homo-polymerization of Grade 1 ATBS, and Grade 2 ATBS yields viscosity of about 12000 cps, and 10560 cps, respectively.
Grades 1, and 2 ATBS were further implemented for synthesizing ATBS polymer/copolymer with acrylamide.
Example 2
Synthesis of ATBS polymer/ copolymer (poly (2-acrylamido-3-methylpropanesulfonate-coacrylamide).
About 40 g of Grades 1, and 2 ATBS prepared in Example 1 were independently dissolved in about 60 g of water to which were added about 48 wt.% aqueous NaOH solution for adjusting the pH to around 8. Water was added to adjust the concentration of ATBS to about 35 wt.%. Then about 55.6 g of about 40 wt.% aqueous acrylamide solution was added, followed by addition of about 5.2 g of water to adjust the concentration of ATBS to about 35 wt.%. Temperature of the resulting reaction solution was controlled at about 30°C, and purged with N2. To the reaction mixes, about 0.7 g of ammonium persulfate, about 0.7 g of sodium sulfite, about 0.6 g of aqueous copper chloride solution containing about 10 mass ppm of copper ion, and about 0.7 g of aqueous solution of about 10 wt.% of V-50 as a diazo type of radical polymerization initiator was added and the reactions were carried out for about 2 h, to separately yield polymers/copolymers of Grade 1, and 2 ATBS with acrylamide, which were subsequently further analysed/characterized.
Characterization of Grades 1, and 2 ATBS polymer/copolymers
Gel permeation chromatography (GPC)
Specific wt.% of Grade 1, and 2 ATBS polymer/copolymers were dried at about 80 °C for about 6h to 10h in a hot air oven. The dry masses obtained as a result were chopped into small pieces to prepare powders using a mixer/grinder. Then the finely divided powders of about 200µm were individually analysed using GPC (see Table 4).
[Table 4]
Grade Polydispersibility index (PI)
Grade 1 1.497
Grade 2 1.432
As per Table 4, the polydispersibility index (PI) of polymer/copolymer of Grade 1, and 2 ATBS with acrylamide are about 1.497, and 1.432 respectively.
As is known to a skilled person in the art, lower polydispersibility index of about 1.497, and 1.432, as is achieved in the instant case, is associated with decrease in the availability of free space, and subsequently, increase in the viscosity and accomplishment of enhanced oil recovery.
Polymer viscosity (see Table 5)
About 1.15 g of polymer/copolymers of Grade 1, and 2 ATBS with acrylamide were separately dissolved in about 393 g of demineralized water, and analysed for viscosity at about 25°C using conventionally known methods such as, Digital Brookfield Viscometer.
[Table 5]
Spindle rpm Torque Viscosity (cps)
Grade 1 ATBS polymer/copolymer 2 150 10.4 28.3
Grade 2 ATBS polymer/copolymer 2 150 10.7 23.7
As per Table 5, the polymer viscosity of Grade 1 ATBS polymer/copolymer was 28.3 cps, whereas that of Grade 2 ATBS polymer/copolymer was 23.7 cps.
Polymer salt viscosity (see Table 6)
About 1.15 g of ATBS Grade 1, and 2 polymer/copolymers with acrylamide were separately dissolved in about 393 g of demineralized water to which was added about 23.4 g of sodium chloride to obtain samples for viscosity measurement (Individual polymer/copolymer concentration: 0.25wt.%). The measurement of viscosity was carried out by using conventionally known methods such as, Digital Brookfield Viscometer at about 25°C temperature.
[Table 6]
Spindle rpm Torque Viscosity (cps)
Grade 1 ATBS polymer/copolymer 2 150 6.7 17.9
200 10.1 22.4
Grade 2 ATBS polymer/copolymer 2 150 6.4 17.1
200 10.5 20.4
As per Table 6, the salt viscosities of Grade 1 ATBS polymer/copolymer at 150 rpm, and 200 rpm were about 17.9 cps, and about 22.4 cps, respectively, whereas that of Grade 2 ATBS polymer/copolymer were about 17.1 cps, and about 20.4 cps, at the said rpm.
Through above studies, it was demonstrated that Grades 1, and 2 ATBS obtained in the present disclosure had low particulate size, and narrow particulate size distribution.
Now, it is known that the physical properties of dispersed monomers, including the monomeric size distribution, and average monomeric particulate size affect the overall polymer/copolymer characteristics, such as their viscosity, and that highly viscous polymers/copolymers increase the viscosity of water phase and reduce the water-oil mobility ratio, thereby improving sweep efficiency, and escalating the EOR. Grades 1, and 2 ATBS achieved in the present case can therefore be feasibly implemented for achieving escalated EOR.
Grade 1 ATBS polymer/copolymer obtained as a result was further implemented for synthesizing ATBS polymer/copolymer hydrogel (hydrogel), which was characterized for EOR implementation through rheological studies (viscosity measurement, amplitude sweep experiment, and frequency sweep experiment).
Example 3
Synthesis of ATBS (polymer/ copolymer) hydrogels.
Different concentrations of Grade 1 ATBS polymer/copolymer powder obtained in Example 2 were preheated at about 100°C for about 1 h with simultaneous addition of water. ATBS solutions (hydrogel) having different concentrations of ATBS were stirred at around 200 rpm for about 2 h, at about 25°C, and resulting hydrogels were characterized.
Rheological properties of different concentrations of ATBS hydrogel were studied, the measurements performed using a stress-controlled Anton Paar MCR 702 rheometer. A cone-plate geometry (CP-25) with sandblasted bottom plate was used for the experiment and a sample volume of 0.07 ml was loaded in CP-25 geometry. The temperature of the sample was controlled using a Peltier unit and a water circulation system for counter-cooling. Silicon oil was used as a solvent trap.
Rheological studies:
Viscosity measurement
Effect of ATBS hydrogel concentration on viscosity at constant temperature
The viscosity ? of different concentrations of ATBS hydrogel was measured as a function of shear rate (???) at about 25°C (see Table 7, and Fig.7)
[Table 7]
ATBS Hydrogel concentrations Zero Shear Viscosity (Pa.s) Shear thinning/Flow index
0.1 20.27 0.937
0.5 36.20 1.007
1.0 130.29 1.163
2.0 207.51 1.302
3.0 393.68 1.382
As per Table 7, and Fig. 7, the viscosity vs. shear rate of the ATBS hydrogel showed a shear thinning behaviour i.e., viscosity decreased with an increase in shear rate. The plateau at lower shear rates referred to as the zero-shear viscosity of ATBS hydrogel, and the slope of the curve is related to the flow index m of ATBS hydrogel.
Zero-shear viscosity of the ATBS hydrogel and the flow index were observed to increase with the increase in concentration. This indicated that at a fixed temperature, the viscosity of the aqueous solution of ATBS polymer (hydrogel) increased with the increase in the concentration of ATBS polymer/copolymer in water.
Effect of temperature on viscosity at varying ATBS hydrogel concentrations
The viscosity ? of different concentrations of ATBS hydrogel was measured as a function of shear rate (???) at several different temperatures (see Table 8, and Figs. 8 (A-C)).
[Table 8]
Temperature Zero Shear Viscosity (Pa.s) Shear thinning/Flow index
0.1 % w/w ATBS hydrogel concentration (see Fig. 8A)
25°C 7.9 0.887
60°C 12.07 0.799
80°C 21.13 0.82
0.5 % w/w ATBS hydrogel concentration (see Fig. 8B)
25°C 36.69 0.981
60°C 29.55 1.007
80°C 29.93 0.905
1.0 % w/w ATBS hydrogel concentration (see Fig. 8C)
25°C 37.57 1.228
60°C 29.50 1.163
80°C 37.44 1.097
As per Table 8, and Figs. 8 (A-C), the zero-shear viscosity of ATBS hydrogel at a concentration of about 0.1 % w/w decreased gradually with the increase in solvent temperature. Whereas the zero-shear viscosity of ATBS hydrogel at the concentrations of about 0.5 % w/w and about 1.0 % w/w did not change with the increase in solvent temperature, thereby deducing that the strength of the ATBS hydrogel at a concentration above about 0.5 % w/w was unaffected by the temperature.
Effect of salt on viscosity at varying ATBS hydrogel concentrations
Viscosity ? of different concentrations of ATBS hydrogel was measured as a function of shear rate (???) with about 1000 ppm of NaCl salt at about 25°C (see Table 9, and Figs. 9 (A-C)).
[Table 9]
Salt Concentration Zero Shear Viscosity (Pa.s) Shear thinning/Flow index
0.1 % w/w ATBS hydrogel concentration (see Fig. 9A)
No Salt 21.1 0.89
1000 ppm 9.86 0.90
0.1 % w/w ATBS hydrogel concentration (see Fig. 9B)
No Salt 36.7 0.98
1000 ppm 24.2 1.71
0.1 % w/w ATBS hydrogel concentration (see Fig. 9C)
No Salt 31.3 0.99
1000 ppm 24.4 1.04
As per Table 9, and Figs. 9 (A-C), the zero-shear viscosity of ATBS hydrogel at a concentration of about 0.1 % w/w decreased in the presence of salt. The zero-shear viscosity of ATBS hydrogel at a concentration of about 0.5 % w/w showed small decrease in the presence of salt. The zero-shear viscosity of ATBS hydrogel at a concentration of about 1.0 % w/w showed no decrease in the presence of salt, thereby deducing that the strength of the ATBS hydrogel at a concentration about 1.0 % w/w was unaffected in the presence of about 1000 ppm of NaCl.
Amplitude Sweep Experiment
Oscillatory strain amplitude sweep rheological experiments of aqueous ATBS polymer solutions were performed at a fixed angular frequency ? = 1 rad/s. In these experiments, storage modulus (G’) and viscous modulus (G”) were measured as a function of shear strain (?) for several different concentrations of ATBS polymer solution at different temperatures and salt concentrations.
Effect of ATBS hydrogel concentration on yield stress and strain (at constant temperature)
Storage modulus (G’) and viscous modulus (G”) were measured as a function of shear strain (?) for several different concentrations of ATBS hydrogel at about 25°C (see Table 10, and Fig. 10).
[Table 10]
Concentration (% w/w) Yield stress (pa) Yield strain (%)
0.1 0.33 5.0
0.5 4.47 63.6
1.0 12.78 81.0
2.0 33.15 80.1
4.5 77.73 63.6
As per Table 10, and Fig. 10, yield strain and yield stress values of the ATBS hydrogel increased with the increase in ATBS concentration in ATBS hydrogel.
Effect of temperature on yield stress and strain at varying ATBS hydrogel concentrations
Storage modulus (G’) and viscous modulus (G”) of the ATBS hydrogel (at varying concentrations) were measured as a function of shear strain (?) at several different temperatures (see Table 11, and Figs. 11(A-C)).
[Table 11]
Temperature Yield stress (Pa) Yield strain (%)
0.1 % w/w ATBS hydrogel concentration (see Fig. 11A)
25°C 0.33 5
60°C 0.02 0.32
80°C 0.01 0.25
0.5 % w/w ATBS hydrogel concentration (see Fig. 11B)
25°C 1.94 25.3
60°C 1.77 20.1
80°C 0.95 12.7
1.0 % w/w ATBS hydrogel concentration (see Fig. 11C)
25°C 8.22 63.6
60°C 7.47 63.6
80°C 8.3 63.6
As per Table 11, and Figs. 11(A-C), the strength and structure of the ATBS hydrogels were not affected by the solvent temperature for concentrations above about 0.5 % w/w.
Effect of salt on yield stress and strain at varying ATBS hydrogel concentrations
Storage modulus (G’) and viscous modulus (G”) of the ATBS hydrogels (at varying concentrations) were measured as a function of shear strain (??) after adding about 1000 ppm of NaCl salt at about 25°C (see Table 12, and Figs. 12 (A-C)).
[Table 12]
Salt Concentration Yield stress (Pa) Yield strain (%)
0.1 % w/w ATBS hydrogel concentration (see Fig. 12A)
No Salt 0.63 10.1
1000 ppm 0.66 25.2
0.1 % w/w ATBS hydrogel concentration (see Fig. 12B)
No Salt 2.99 40.1
1000 ppm 0.78 20.1
0.1 % w/w ATBS hydrogel concentration (see Fig. 12C)
No Salt 5.47 40.1
1000 ppm 3.83 40.1
As per Table 12, and Figs. 12(A-C), the effect of an increase in salt concentration on the strength and structure of the ATBS hydrogels reduced with the increase in the ATBS concentration in ATBS hydrogels.
Frequency Sweep Experiment
Frequency sweep rheological experiments of the ATBS hydrogel were performed at a fixed oscillatory strain amplitude ? = 0.2%. In these experiments, viscoelastic moduli such as storage modulus (G’) and viscous modulus (G”) were measured as a function of angular frequency (?) for several different concentrations of ATBS polymer solution at several different temperatures and salt concentrations.
Effect of ATBS hydrogel concentration on relaxation time scales
Storage modulus (G’) and viscous modulus (G”) were measured as a function of angular frequency (?) for several different concentrations of ATBS hydrogel at about 25°C (see Fig. 13).
As per Fig. 13, the storage modulus (G’) and viscous modulus (G”) showed a frequency dependence behaviour over the entire range of frequency explored. The values of G’ and G” decreased with the decrease in angular frequency. G’ and G” values cross each other at lower as well as at higher frequencies. Overall, two crossovers were seen over the entire range of frequency. Since the inverse of frequency represents the relaxation time of ATBS polymer (Grade 1 ATBS polymer/copolymer in the present case) in ATBS hydrogel. The two crossovers represent the two relaxation time scales of the ATBS polymer such as fast and slow relaxation time scales. It was further noted that the crossover of G’ and G” shifted to a lower frequency with the increase in ATBS polymer (Grade 1 ATBS polymer/copolymer) concentration in an aqueous solution. This indicated that the disentanglement of Grade 1 ATBS polymer/copolymer in ATBS hydrogel took a long time with the increase in ATBS polymer concentration in an aqueous solution (ATBS hydrogel).
Effect of temperature on relaxation time scales at varying ATBS hydrogel concentrations.
Storage modulus (G’) and viscous modulus (G”) of ATBS hydrogel at varying concentrations were measured as a function of angular frequency (?) at different temperatures (see Figs. 14(A-C)).
As per Figs. 14(A-C), the frequency sweep data of about 0.1 % w/w (see Fig. 14A), about 1.0 % w/w (see Fig. 14B), and about 2.0 % w/w (see Fig. 14C) of the ATBS hydrogel were the same. However, the crossover of G’ and G” at higher frequency vanished with the increase in temperature for all concentrations. This indicated the absence of faster relaxation time scales in the ATBS hydrogel at a higher temperature.
Effect of salt on relaxation time scales at constant ATBS hydrogel concentrations.
Storage modulus (G’) and viscous modulus (G”) of ATBS hydrogels were measured as a function of angular frequency (?) after adding about 1000 ppm of NaCl salt at about 25°C (see Fig. 15).
As per Fig. 15, G’ and G” became more frequency dependent in the presence of NaCl salt. However, the crossover of G’ and G” at lower frequency vanished in the presence of salt. This indicated the absence of slower relaxation time scales in ATBS hydrogel in the presence of salt.
The foregoing rheological studies may also be carried out for ATBS hydrogel synthesized using Grade 2 ATBS polymer/copolymer.
The rheological studies of ATBS hydrogel described in the present disclosure help in identifying appropriate concentrations of ATBS hydrogels to be implemented as per the process parameters/conditions to facilitate feasible and elevated EOR.
The foregoing process may be modified or tailored to consumers specifications and market requirements of ATBS polymer/copolymer.
The foregoing process may be manual, semi-automated or automated.
Further, it may be carried out as continuous, semi-continuous, batch, and/or fed batch process. It may also be implemented for small, medium, and/or large-scale production of ATBS and/or polymer/copolymer thereof.
List of Abbreviations
ATBS – Acrylamide tertiary butyl sulfonic acid
ACRN – Acrylonitrile
IB – Isobutylene
The embodiments, examples and alternatives of the preceding paragraphs or the description and drawings, including any of their various aspects or respective individual features, may be taken independently or in any combination. Features described in connection with one embodiment are applicable to all embodiments, unless such features are incompatible.
The preferred embodiments of the present invention are described in detail above. It should be understood that ordinary technologies in the field can make many modifications and changes according to the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by those skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should fall within the protection scope determined by the claims.

,CLAIMS:WE CLAIM:
1. Acrylamide tertiary butyl sulfonic acid (ATBS) comprising particulates characterized in that,
d10 of said particulates ranges from 1.2 µm to 2.1 µm;
d50 of said particulates ranges from 11 µm to 16 µm; and
d90 of said particulates ranges from 61 µm to 70 µm.

2. The ATBS as claimed in claim 1, wherein,
d10 of the particulates ranges from 1.3 µm to 1.4 µm;
d50 of the particulates ranges from 11.5 µm to 11.7 µm; and
d90 of the particulates ranges from 61.8 µm to 70.0 µm.

3. The ATBS as claimed in claim 1, wherein,
d10 of the particulates ranges from 1.9 µm to 2.2 µm;
d50 of the particulates ranges from 15.0 µm to 15.4 µm; and
d90 of the particulates ranges from 69.5 µm to 69.9 µm.

4. The ATBS as claimed in claim 1, wherein average particulate size of the ATBS is = 0.4 µm.

5. The ATBS as claimed in claim 1, wherein acid function of the ATBS is = 99%.

6. The ATBS as claimed in claim 1, wherein homo-polymerization of the ATBS yields polymer having viscosity within a range of 10000-12000 cps.

7. A process for synthesizing ATBS comprising:
preparing a sulfonating mixture;
reacting said sulfonating mixture with acrylonitrile (ACRN) to obtain ACRN-sulphate;
reacting said ACRN-sulphate with isobutylene (IB) to obtain ATBS slurry; and
purifying said ATBS slurry
to obtain said ATBS comprising particulates characterized in that,
d10 of said particulates ranges from 1.2 µm to 2.1 µm;
d50 of said particulates ranges from 11 µm to 16 µm; and
d90 of said particulates ranges from 61 µm to 70 µm.

8. The ATBS as claimed in claim 7, wherein,
d10 of the particulates ranges from 1.3 µm to 1.4 µm;
d50 of the particulates ranges from 11.5 µm to 11.7 µm; and
d90 of the particulates ranges from 61.8 µm to 70.0 µm.

9. The ATBS as claimed in claim 7, wherein,
d10 of the particulates ranges from 1.9 µm to 2.2 µm;
d50 of the particulates ranges from 15.0 µm to 15.4 µm; and
d90 of the particulates ranges from 69.5 µm to 69.9 µm.

10. The process as claimed in claim 7, wherein ACRN: IB is either about 10-12: 1 or about 13-17:1.

11. The process as claimed in claim 7, wherein % of ATBS slurry obtained is either about 19% ± 1% or about 16% ± 1%.

12. The process as claimed in claim 7, wherein ratio of ATBS slurry to washing liquid is either about 1:2-3 or about 1:6-7

Dated 25th Day of February 2023

Deepak Pawar
Agent for the Applicant
IN/PA-2052