Carbon capture

Abstract

Methods, processes, compositions, systems and uses for separating acidic gases such as carbon dioxide from a gaseous mixture containing such acidic gases, utilising a dispersion of at least one organic base and an oleaginous medium, the dispersion further comprising at least one ionic surfactant, such as a metal-containing ionic surfactant.

Description

[0001] CARBON CAPTURE

[0002] This invention relates to methods, processes, compositions, systems and uses relating to the separation of acidic gases from a gaseous mixture. In particular, the invention relates to methods, processes, compositions, systems and uses for the separation of sulphur dioxide, nitrogenous oxides (especially nitrogen dioxide) and carbon dioxide, and preferably carbon dioxide, from a gaseous mixture containing sulphur dioxide, nitrogenous oxides (especially nitrogen dioxide) and / or carbon dioxide, and preferably carbon dioxide, such as that formed during the combustion of fossil fuels.

[0003] Background of the Invention

[0004] The removal of carbon dioxide (CO2) and other acidic gases from gaseous mixtures is of increasing industrial importance. Carbon dioxide is the inevitable by-product of the combustion of fossil fuels such as gas, coal, and oil. It is also generated in many other industrial processes, for example during the manufacture of cement. The adverse effects caused by the release of CO2into the atmosphere have been identified for many years and governments and international organisations around the world have recognised the need to reduce CO2emissions to combat global warming. International agreements such as the 2016 Paris Agreement set goals aimed at significantly reducing CO2emissions from all sources and individual countries and industries have since adopted ‘net-zero’ targets whereby CO2emissions are to be removed or abated entirely. These are ambitious targets but there is a broad consensus that action should be taken to avoid the impact of climate change.

[0005] The Inter-governmental Panel on Climate Change (IPCC) estimates that more than three-quarters of global CO2emissions are attributable to the burning of fossil fuels for power (electricity) generation. The majority of the remainder can be attributed to industrial processes including cement manufacture, refinery operations, iron and steel manufacturing and the petrochemical industry. Methods able to remove or capture CO2from these sources, and from other processes where CO2is present or produced, would thus be of significant benefit to efforts to reduce atmospheric CO2and so ameliorate global warming. In processes in which CO2is present, for example in which CO2is emitted or produced, other acidic gases may also be present. Gases such as sulphur oxides, nitrogen oxides and hydrogen sulphide are also detrimental to the atmosphere and to public health and so a method for the removal or capture of these gases too would be of great benefit.

[0006] Techniques for the absorption of CO2using liquid absorbents are known in the art. Most commonly, liquid amine absorbents such as alkanolamines dissolved in water are used. CO2-containing gas streams are contacted with the absorbent where the CO2reacts with the amine to produce carbamate, carbonate and bicarbonate species thereby trapping the CO2by chemical means. The ammonium salts that form are thermally unstable so in a secondary stage it is possible to liberate the captured CO2by heating and thus regenerate the liquid amine absorbent. The process is thus cyclic allowing repeated use of the same liquid absorbent. Common amines used in aqueous solution include monoethanolamine (MEA), diethanolamine (DEA), methyldiethanolamine (MDEA) and triethanolamine (TEA), 2-Amino-2-methyl-1 -propanol (AMP) and piperazine (PZ). The CO2liberated through the thermal decomposition of the species formed can be collected and either employed in other processes (termed “utilisation”) or it may be removed from the atmosphere altogether, for example by pumping it into disused oilwells, mines or other undergroundstructures (termed “storage”). The cyclic process thus enables the effective removal of CO2 from CO2-containing gas streams. This is often referred to as Carbon Capture and Storage (CCS) or Carbon Capture, Utilisation and Storage (CCUS).

[0007] Although effective, there are several drawbacks with the use of aqueous amine solutions as liquid absorbents for CCS / CCUS operations. The main drawback is the amount of energy needed. In part, due to the high volatility of water, the absorption of CO2proceeds at a relatively low temperature such as from ambient temperature up to about 50°C. This needs to be increased significantly such that the vapour-liquid equilibrium drives the CO2-absorbed ammonium species to thermally decompose and so liberate CO2(for example, typically this may require raising the temperature to above 100°C, which in the case of aqueous solutions results in significant water vaporisation, even at elevated pressure, which consumes significant energy that is difficult to recover). The carbon capture process employs large volumes of the liquid absorbent and so the amount of energy needed to maintain the required temperature is also large, mainly owing to the relatively high specific heat capacity of water (4.2 kJ kg1K1) and specific enthalpy of vaporisation (2260 kJ kg1@ 100°C). The use of water also gives rise to corrosion problems which may require engineering mitigation, such as the selection of construction materials. It would thus be highly advantageous to be able to reduce the amount of energy required in a cyclic CCS / CCUS process. Further desirable attributes for a useful carbon capture composition include a high amine concentration (such as above 20% by weight), compositional stability to prevent the possibility of the product separating during transit, storage and / or plant operational shutdown, and low viscosity to facilitate pumping on plant.

[0008] US 9,713,788 attempts to mitigate the problems associated with the use of aqueous absorbent solutions by instead employing an amine dissolved in an aprotic solvent. Examples of amines used include some of those mentioned hereinabove as well as compounds such as 1,5-diamino-3-oxapentane (DAOP), aminopropionitrile (APN), 2-ethoxyethyl amine (2EEA), 1,5-bis(methylamino)-3-oxapentane (BMAP), polyethyleneimine (PEI) and monoepoxide modified PEI up to 15 wt%; and examples of aprotic solvents used include dimethylsulphoxide (DMSO). However, such approaches require the selection of amines which can be dissolved in such aprotic solvents and may not be as effective as other options. The purported improvements may also be eroded through the environmental sustainability, handling considerations and cost of the aprotic solvents, which also need to be made available in large quantities, and the apparently low amine loadings.

[0009] Academic attempts have been made to produce water-in-oil emulsions using solutions of amines in water for the purposes of carbon capture via common fatty acid-sorbitan based surfactants such as SPAN80 and TWEEN80 and a kerosene oil phase (Najib, S. B. M., Kamaruddin, K. S. N., Rashid, N. M., Ibrahim, N„ Sokri, M. N. M„ Zaini, N„ & Nordin, N. (2022). The Effect of MDEA / AMP and Span-80 in Water-in-Oil (W / O) Emulsion for Carbon Dioxide Absorption. Journal of Applied Membrane Science & Technology, 26(2), 17-27, (https: / / doi.org / 10.11113 / amst.v26n2.236); S. B. Mohd Najib, M. N. Mohd Sokri, N. Mohamed Rashid et al., Determination of mass transfer coefficient of CO2removal in water-in-oil emulsion, Materials Today: Proceedings, 2023, (https: / / doi. Org / 10.1016 / j.matpr.2023.01.105), M. N. M. Sokri et al., Emulsion Stability and CO2Removal Performance of MDEA-AMP Blends with Tween-80 Surfactants. Jumal Kejuruteraan 35(5) 2023: 1145-1151, (https: / / d0i.0rg / l 0.17576 / jkukm-2023-35(5)-15)).However, these approaches used highly dilute amines in water, targeting only around 4-8 volume% amine in the finished emulsion with typically 42-46 volume% water and failed to make an emulsion with stability greater than 24 hours before visibly separating.

[0010] Accordingly, there remains a need for acidic gas separation and carbon capture approaches that can overcome the above problems, and in particular approaches that offer improved alternatives to simple aqueous amine solutions.

[0011] Summary of the Invention

[0012] Surprisingly, it has now been found that a separation composition comprising an amine dispersed in, for example, a nonaqueous solvent (e.g. an oleaginous fluid or base oil), stabilized with at least one ionic surfactant or metal-containing ionic surfactant, achieves a high degree of acidic gas separation, and avoids many of the main drawbacks of aqueous amine systems. Using a non-aqueous solvent of higher initial boiling point and lower specific heat capacity compared with water reduces volatile solvent losses especially during the higher temperature decomposition stage necessary for solvent regeneration, and thus reduces the energy input required of the whole process. The non-volatile solvent also allows for significantly higher temperature to be used for desorbing acidic gases separated utilising the methods, processes, compositions, systems and uses of the present invention, thus further improving the overall efficiency of the process by mitigating irretrievable energy loss to evaporation. In addition, using a surfactant stabilised amine dispersion has surprisingly been found to reduce volatile losses of the amine itself, thus reducing the requirement for emissions aftertreatment and increasing the service life of the active amine in the solvent.

[0013] The present invention therefore provides methods and processes for separating acidic gases, such as (and in particular) carbon dioxide (CO2) from a gaseous mixture which uses considerably less energy than established methods employing aqueous absorbent solutions, enabling a more efficient cyclic CCS / CCUS procedure to be established, while also mitigating the other problems associated with existing non-aqueous solvents.

[0014] Accordingly, in a first aspect the present invention provides a method of separating acidic gases from a gaseous mixture containing such acidic gases, the method comprising contacting the gaseous mixture with a dispersion of at least one organic base and a base oil, the dispersion further comprising an ionic surfactant or metal-containing ionic surfactant.

[0015] In a second aspect, the present invention provides a process for separating acidic gases from a gaseous mixture comprising such acidic gases, comprising the steps of: providing, charging or loading a vessel with a composition comprising a dispersion of at least one organic base and a base oil, the dispersion further comprising an ionic surfactant or metal-containing ionic surfactant; and introducing the gaseous mixture to the vessel.

[0016] In a third aspect, the present invention provides a composition for separating acidic gases from a gaseous mixture comprising such acidic gases, the composition comprising a dispersion of at least one labile organic base in a base oil, the dispersion further comprising an ionic surfactant or metal-containing ionic surfactant.

[0017] In a fourth aspect, the present invention provides an acidic gas separation system, being a system forseparating acidic gases from a gaseous mixture comprising such acidic gases, the system comprising a vessel with means for fluid introduction and removal, wherein the vessel contains a composition according to the third aspect of the invention.

[0018] In a fifth aspect, the present invention provides uses of a composition comprising a dispersion of at least one organic base and a base oil, the composition further comprising an ionic surfactant or metal-containing ionic surfactant, to separate acidic gases from a gaseous mixture containing such acidic gases and to capture carbon dioxide from a gaseous mixture comprising carbon dioxide.

[0019] As introduced above, employing an oleaginous fluid rather than an aqueous fluid such as water permits significant energy savings when the aspects of the present invention form part of a cyclic CCS undertaking or operation. This is in part because the specific heat capacity of oleaginous fluids is lower than that of water. For example, a base oil of the type conventionally used as a lubricating oil typically has a specific heat capacity of 2.0 kJ kg1K1. This is less than half of the specific heat capacity of water of 4.2 kJ kg1K1, so the amount of energy required to maintain the required temperature differential for both capture and release of acidic gases is markedly lower. Notably, an oleaginous fluid may provide improved resilience of the acidic gas (especially carbon dioxide) separation composition to hotter gaseous mixtures, such as flue gases or exhaust gases, meaning that less energy needs to be expended to cool the gaseous mixture before introducing it to an acidic gas separation process, and less energy is required to heat the composition following separation of acidic gas from the gaseous mixture to a temperature at which the acidic gas (which may especially be carbon dioxide) is released from the acidic gas separation composition.

[0020] Brief Description of the Drawings

[0021] FIGURE 1 shows a schematic representation of an apparatus or system suitable for the processes and methods described in accordance with the present invention.

[0022] FIGURE 2 shows a graph of CO2loading achieved from processes and methods of examples described in accordance with the present invention, on a mass basis.

[0023] FIGURE 3 shows a graph of CO2loading achieved from processes and methods of examples described in accordance with the present invention, on a molar basis.

[0024] Detailed Description of the Invention

[0025] Compositions referred to in accordance with any aspect of the present invention comprise a dispersion of at least one organic base and a base oil, the dispersion further comprising at least one surfactant, wherein at least one surfactant is an ionic surfactant. Accordingly, the compositions present in accordance with any aspect of the invention may comprise a dispersion of at least one organic base in a base oil, the dispersion further comprising at least one surfactant, wherein at least one surfactant is an ionic surfactant. As used herein, the term “dispersion” means a chemical system in which particles, in any state of matter, are distributed in another material of the same or different state of matter to the particles. The continuous phase (or external phase) is typically a liquid and the discontinuous phase (or internal phase), formed by the particles, is typically a liquid, a solid or a semi-solid, such as a gel or sol. The dispersion may therefore be a liquid-in-liquid dispersion and may therefore be alternatively described as an emulsion. An emulsion may be formed by using a liquid organic base or by using an organic base solubilised in a hydrophilicmedium, such as an aqueous organic base. An organic base solubilised in a hydrophilic medium, or an aqueous organic base may be notably applied where the organic base is solid in standard conditions. Many dispersions ordinarily exhibit stability for a finite period of time. Dispersion stability may be assessed by placing a 100 mL sample in a 100 mL borosilicate glass centrifuge tube, for example a conical bottom tube of length 203mm and neck ID 17mm, SKU 1197102. The centrifuge tube is inspected at 24hours, and then at weekly intervals thereafter. If any layering or phase separation is observed (visible to the naked eye) in the sample, it is deemed to have become unstable since the previous inspection. Hence, samples can be said to be stable for <24 hours, 24 -168 hours, 1 - 2 weeks, 2 - 3 weeks, 3 - 4 weeks or > 4 weeks. In preferred embodiments, the dispersion is stable (and may be measured so in accordance with the method described above) for at least about 24 hours (or about 1 day), preferably for at least about 168 hours (or about 1 week), more preferably for at least about 2 (two) weeks, even more preferably for about 3 (three) weeks and even more preferably still for about 4 (four) weeks or more, as defined above. While it is preferred and understood that no upper limit on stability exists, examples include about 15 weeks; about 20 weeks; about 25 weeks; about 30 weeks; about 40 weeks; about 50 weeks; about 1 year; about 2 years; about 3 years; about 5 years; about 10 years; up until utilisation in a method, process, system, or use in accordance with the present invention; and indefinitely. Accordingly, the stability of the dispersion may be from about 24 hours (or 1 day) to about 15 weeks, about 24 hours (or 1 day) to about 20 weeks, about 24 hours (or 1 day) to about 25 weeks and so on, about 48 hours (or 2 days) to about 15 weeks, about 48 hours (or 2 days) to about 20 weeks, and so on; and also so on for each lower and upper limit provided above. Dispersion stability is a measure of product homogeneity and is highly desirable to prevent the possibility of the product separating. It is desirable to keep the product homogeneous for as long as possible to prevent blockage of pumps, to prevent the corrosion of steel components by direct exposure to amines, water or a mixture or amines and water, and to ensure the product has a consistent viscosity throughout any storage and use. Furthermore, the more stable the dispersion, the higher the proportion of internal phase is in principle achievable, and consequently the higher the loading of organic base that may be incorporated into the dispersion. A high organic base loading is believed to correlate with higher acidic gas loading potential, thus facilitating a more efficient acidic gas capture process. Product homogeneity is therefore an important consideration throughout the distribution, storage, and plant operation periods of use. Low viscosity is desirable, particularly in combination with dispersion stability for the facility design and low cost of movement of the product throughout the distribution, storage, and plant operation periods of use.

[0026] Base oil

[0027] In respect of compositions relating to any aspect of the present invention, the base oil typically forms the continuous phase (also known as the external phase) of the dispersion or composition. Accordingly, the base oil would ordinarily be present in a significant amount, that is to say in an amount of from about 10% to about 90%, preferably from about 20% to about 80%, more preferably from about 30% to about 70%, even more preferably from about 40% to about 60% and even more preferably still from about 45% to about 55%, in each case by mass of the composition or of the dispersion.

[0028] The base oil may be any liquid oleaginous medium or oleaginous fluid (also known as oleaginous liquid)and may alternatively be described in general as a liquid hydrophobic medium or hydrophobic fluid (also known as hydrophobic liquid). Accordingly, the base oil (or the molecules thereof) would typically consist of carbon atoms, hydrogen atoms and less than about 2% heteroatoms, preferably less than about 1 % heteroatoms, more preferably less than about 0.5% heteroatoms, even more preferably less than about 0.2% heteroatoms and even more preferably still less than about 0.1% heteroatoms on a mass basis. In each case there may be a lower limit of zero, substantially zero (e.g. below the limit of detection), or only trace amounts of heteroatoms. The base oil may therefore include organic solvents such as hydrocarbon solvents, mineral oils, lubricant base stocks or other organic or hydrocarbonaceous (or predominantly hydrocarbonaceous) fluids, especially those meeting the definition of carbon atom, hydrogen atom and heteroatom contents above. Preferably the base oil will be non-volatile under the conditions of acidic gas separation and release. Volatility may be determined by the initial boiling point (IBP) of the liquid, as measured by ASTM 7500. Some preferred IBP temperatures for the base oil may therefore be at least about 100°C, preferably at least about 120°C, more preferably at least about 140°C and more preferably still at least about 160°C.

[0029] The base oil is also preferably non-polar, substantially non-polar, or of low polarity. The base oil may therefore be selected so that the solubility of the organic base in the base oil may be not greater than about 5 percent mass / mass (% m / m), preferably not greater than about 2% m / m, more preferably not greater than about 1% m / m, even more preferably not greater than about 0.5% m / m and even more preferably still not greater than about 0.1% m / m, measured under standard conditions.

[0030] The base oil may be comprised of one or more base stocks. That is to say, the base oil may be a single base stock or may comprise a mixture of base stocks. As defined by the American Petroleum Institute (API), a base stock is a lubricant component that is produced by a single manufacturer to the same specifications (independent of feed source or manufacturer’s location); that meets the same manufacturer’s specification; and that is identified by a unique formula, product identification number, or both. Base stocks may be manufactured using a variety of different processes including but not limited to distillation, solvent refining, hydrogen processing, oligomerization, esterification, and rerefining. Rerefined stock shall be substantially free from materials introduced through manufacturing, contamination, or previous use. Nonlimiting examples of base stocks that may be used in or as the base oil include ExxonMobil AP / E CORE 100 (APE100, Group I), ExxonMobil EHC 45 (EHC45, Group II), Yubase2 (Group III), ExxonMobil Spectrasyn2 / Spectrasysn4 (Group IV), ExxonMobil Synesstic5 (Group V). The base oil, or continuous phase may also comprise hydrocarbonaceous materials not formally classified under the API system. Nonlimiting examples of such unclassified materials include Shell Neoflo 1-58, and ExxonMobil Isopar M. In some preferred embodiments, the base oil may comprise or consist of Group I base stock, Group II base stock, Group III base stock, Group IV base stock or mixtures thereof, as defined in accordance with the API base stock classification system, as defined in Annex E of API 1509-2022, base oil interchangeability guidelines for passenger car motor oils and diesel engine oils. This system is described in Table 1 below, in which percentages given are mass percent.

[0031] TABLE 1: API Base Stock Classification System

[0032] Group Viscosity Index (x) Saturates Sulphur NotesContent Content

[0033] I 80 < x < 120 < 90 % and / or > 0.03%

[0034] II 80 < x < 120 > 90 % and < 0.03%

[0035] III x > 120 > 90 % and < 0.03%

[0036] IV Not specified Not specified All Poly Alpha Olefins (PAO) V Not specified Not specified All other base stocks

[0037] For the purposes of classifying a base stock, viscosity index may be measured according to ASTM D2270, saturates content may be measured according to ASTM D2007 and sulphur content may be measured according to one of ASTM D1552, D2622, D3120, D4294 and / or D4927. In each case, the API classification indicates that the most recent version of each standard shall be used. As such, ASTM D2270-10(2016) may be used to measure the viscosity index of a base stock, ASTM D2007-19(2020) may be used to measure the saturates content of a base stock and any of ASTM D1552-16(2021 ), D2622-21, D3120-08(2019), D4294-21, or D4927-20 may be used to measure the sulphur content of a base stock. The base stock(s) forming the base oil may be new (including synthetic), reused, rerefined or recycled base stocks.

[0038] In order to improve the energy efficiency of heating required to facilitate the acidic gas separation and release processes, a lower specific heat capacity of the base oil is desirable. In some preferred embodiments, the specific heat capacity of the base oil (or the separation composition) is accordingly less than about 4.2 kJ kg-1K1, preferably less than about 4.0 kJ kg-1K1, more preferably less than about 3.5 kJ kg1K1, even more preferably less than about 3.0 kJ kg-1K1, such as, by way of non-limiting example, from about 1.0 kJ kg1K1to about 3.0 kJ kg-1K1, from about 1.5 kJ kg-1K1to about 2.5 kJ kg-1K1or from about 1.75 kJ kg-1K1to about 2.25 kJ kg-1K1.

[0039] Organic base

[0040] In respect of compositions relating to any aspect of the present invention, an organic base typically forms the discontinuous phase (also known as internal phase or dispersed phase) of the composition. Any organic base that is not miscible with the base oil may be employed in the present invention. As used herein, the term “not miscible” means that not greater than about 5 percent mass / mass (% m / m) of the organic base dissolves in the base oil, preferably not greater than about 2% m / m, more preferably not greater than about 1 % m / m, even more preferably not greater than about 0.5% m / m and even more preferably still not greater than about 0.1 % m / m, each measured under standard conditions.

[0041] Additionally, or alternatively, the organic base may have a solubility in water under standard conditions of at least about 50 percent mass / mass (% m / m), preferably at least about 70% m / m, more preferably at least about 90% m / m, each measured under standard conditions.

[0042] Examples of organic bases include amines. Accordingly, in some preferred embodiments, the organic base is an amine, or alternatively described is an organic amine. Examples of organic amines include those with primary amine functionality, secondary amine functionality and / or tertiary amine functionality, which may be described as primary amines, secondary amines and tertiary amines. In some further preferred embodiments, the organic base comprises (or contains) primary amine functionality, secondary amine functionality, or both primary and secondary amine functionality. Accordingly, in these further preferredembodiments, the organic base comprises primary amines and / or secondary amines, including without limitation molecules that are both a primary amine and a secondary amine.

[0043] The organic base may be, or comprise, an amine which may contain additional functional groups such as alcohol or amide groups, or mixtures thereof. Useful amine compounds comprise at least one amine group and can also comprise one or more additional amine groups or other reactive or polar groups. These amines may be hydrocarbyl amines or may be predominantly hydrocarbyl amines in which the hydrocarbyl group includes other groups, e.g., hydroxy groups, alkoxy groups, amide groups, nitriles, carbonyls, imidazoline groups, and the like. Suitable hydrocarbyl amines include aryl, cycloalkyl and alkylamines. The amine compounds may have, or have on average, a ratio of carbon atoms to heteroatoms of from about 5:1 to about 1:20, preferably from about 4:1 to about 1:10, more preferably from about 3:1 to about 1:5, even more preferably from about 2:1 to about 1:4 and even more preferably still from about 1:1 to about 1:3. In combination with any of the ranges for the ratio of carbon atoms to heteroatoms above, the heteroatoms used for the purpose of determining said ratio are preferably selected from nitrogen and oxygen, more preferably nitrogen.

[0044] Where the organic base comprises, or is, an amine, the amine comprises a primary, secondary, tertiary, or mixed order amine or alkanolamine (the alkanolamine therefore also comprising primary, secondary, tertiary or mixed order amine functionality), or mixture thereof. Preferred amines include those selected from Piperazine; N-Methyldiethanolamine; Monoethanolamine; 2-Amino-2-methyl-1 -propanol;

[0045] Diethanolamine; Diisopropanolamine; 2-(Methylamino)ethanol; 2-(Dimethylamino)ethanol; 1-(2-aminoethyl)piperazine (AEP); 2-(Ethylamino)ethanol, (2-Hydroxyethyl)ethylenediamine; 1 -Methylpiperazine; 2-Methylpiperazine; 1,4-Piperazinediethanol; 1,4-Piperazinediethylamine; Diethylenetriamine; 3-Amino-1-propanol; Piperidine; Ethylenediamine; N-Methyl-1,3-propanediamine; 2,2-Dimethyl-1,3-propanediamine; 1,3-Diamino-2-propanol; (±)-1-Amino-2-propanol; Triethylamine; Dabco; 1 -Ethylpiperazine; 2,2’-(1,2-Ethanediyldiimino)bis[ethanol]; Putrescine; Morpholine; Diethylamine; Tris(2-aminoethyl)amine; (±)-2-Amino-1 -propanol; 2-Aminoethylpiperazine; 1-(2-hydroxyethyl)piperazine (HEP); Hexahydro-2, 4,6-trimethyl-1,3,5-triazine; Propylenediamine; Triethylenetetramine (TETA); Tetraethylenepentamine (TEPA); Pentaethylenehexamine (PEHA); Hexaethyleneheptamine (HEHA); PAM; H-PAM and mixtures thereof. Particularly preferred amines include Piperazine; N-Methyldiethanolamine; Monoethanolamine; 2-Amino-2-methyl-1 -propanol; Diethanolamine; 1-(2-hydroxyethyl)piperazine (HEP); 1,4-Piperazinediethylamine; 1-(2-aminoethyl)piperazine (AEP); (2-Hydroxyethyl)ethylenediamine; Diethylenetriamine; Triethylenetetramine (TETA); Tetraethylenepentamine (TEPA); 2-Aminoethylpiperazine; Propylenediamine;

[0046] Pentaethylenehexamine (PEHA); Hexaethyleneheptamine (HEHA); PAM; H-PAM; and mixtures thereof. Selected such amines that may be referred to as polyamines, such as PAM and H-PAM, are discussed in further detail below.

[0047] In some preferred embodiments, the organic base comprises both amine and hydroxyl functionality, or alternatively stated, is an alkanolamine and may be an alkanolamine selected from the list of amines or from the list of preferred amines and / or particularly preferred amines above.

[0048] Another important class of organic base is the polyamines, i.e. chemicals comprising a plurality of aminic functional groups, (which as used herein includes without limitation distributions of linear, branchedand / or cyclic alkylene derivatives containing a modal number (n) of aminic functional groups), such as polyamines derived from alkylenes. Polyamines derived from ethylene are preferred for reasons of commercial availability. A detailed description of the preparation and properties of polyamines is contained within the chapter “Diamines and Higher Amines, Aliphatic", Second Edition, Kirk and Othmer, Volume 8, pages 485-519, published by Wiley 2001, the disclosure of which is herein incorporated by reference. Polyamine mixtures are often prepared by the reaction of alkylene (e.g. ethylene) chloride with ammonia or by reaction of an alkylene (e.g. ethylene) imine with ammonia. The resulting product is typically a complex mixture of alkylene (e.g. ethylene) derived polyamines. The polyamine mixture can be separated by fractional distillation to yield fractions, with n typically ranging from about 2 to about 14. Ethylene derived polyamine mixtures can be separated by fractional distillation to yield lighter fractions, with n typically about 2 to about 5, an intermediate mixed fraction commercially referred to as polyamine (PAM) with n typically about 6, and a heavier fraction known commercially as heavy polyamine (H-PAM) with n typically about 7 or higher. The lighter ethylene derived polyamines (such as DETA, TETA, TEPA, etc.) can be used in accordance with the present invention, as well as the heavier PAM and H-PAM mixtures, each separately or in combination. The properties and attributes of polyalkyl polyamines are further described, for example, in U. S. Pat. Nos. 4,938,881; 4,927,551; 5,230,714; 5,241,003; 5,565,128; 5,756,431; 5,792,730; and 5,854,186, the disclosures of each of which are herein incorporated by reference. By way of non-limiting example, a commercially available product containing over 95% TEPA, having structures as previously described, is available from both Huntsman Corporation and Delamine B. V. and is marketed as Tetraethylenepentamine, or simply TEPA. A commercially available PAM typically containing over 90% PEHA, having structures as previously described, and heavier polyamine analogues is also available from Huntsman Corporation under the commercial name “Ethyleneamine E-100”, and from Delamine B. V. under the commercial name “HEPA (higher ethylene polyamines)”. A commercially available H-PAM typically containing over 95% polyamines heavier than or equal to PEHA, with less than 15% PEHA itself, having structures as previously described, is available from Delamine B. V. under the commercial name “HEPA S140”. Selected polyamine organic bases, as well as those taken from the lists of organic bases above, may therefore include: Piperazine; 1-(2-aminoethyl)piperazine (AEP); 2-Aminoethylpiperazine; 1,4-Piperazinediethylamine; Tris(2-aminoethyl)amine; 1-(2-hydroxyethyl)piperazine (HEP); 1,3-Diamino-2-propanol; Triethylenetetramine (TETA); Tetraethylenepentamine (TEPA); Pentaethylenehexamine (PEHA); Hexaethyleneheptamine (HEHA); PAM; H-PAM and mixtures thereof, and more preferable polyamine organic bases include those selected from Piperazine; 1-(2-aminoethyl)piperazine (AEP); 1,4-Piperazinediethylamine; Tetraethylenepentamine (TEPA); PAM; H-PAM and mixtures thereof.

[0049] Ionic Surfactant

[0050] Compositions associated with the present invention comprise at least one ionic surfactant. The ionic surfactant(s) may therefore be considered to be in addition to the base oil and organic base comprised within compositions associated with the present invention. In some embodiments, at least one ionic surfactant is a metal-containing ionic surfactant, e.g. the ionic surfactant is a metal-containing ionic surfactant.

[0051] Any surfactant described herein may also be described as an emulsifier and / or as a dispersant, e.g. theionic surfactant may also be described as the ionic emulsifier or as the ionic dispersant. A dispersant is an additive whose primary function is to hold oil-insoluble substances in suspension (in other words, a dispersant holds oil-insoluble substances in dispersion). For example, a dispersant maintains in suspension oil-insoluble substances, such as oil-insoluble components and in the context of the present invention, the organic base, thus preventing or reducing flocculation and resultant precipitation or deposition on surfaces. Dispersants typically comprise a lipophilic or oleophilic portion (such as a hydrocarbon chain or hydrocarbon moiety) and a hydrophilic, e.g. polar, portion, the polarity being derived from the inclusion of functional groups comprising heteroatoms and / or heteroatomic moieties capable of ionising, preferably heteroatoms covalently bonded to the lipophilic or oleophilic portion, such as metals or moieties comprising sulfur, phosphorous, oxygen and / or nitrogen atoms, preferably oxygen and / or nitrogen atoms, capable of ionising. A heteroatomic moiety capable of ionising may also then be ionically bonded to a metal.

[0052] Accordingly, the ionic surfactant typically comprises a polar head group, the polarity being derived from the inclusion of functional groups comprising heteroatoms and / or heteroatomic moieties capable of ionising, preferably where such functional groups are covalently bonded, directly or indirectly, to the oleophilic / lipophilic portion (e.g. hydrocarbon chain), and more preferably wherein the heteroatoms are metals, oxygen atoms, nitrogen atoms, or mixtures thereof.

[0053] Accordingly, surfactants may typically consist of at least one hydrophilic and at least one hydrophobic group in their chemical structure. Ionic surfactants are a class of surfactant where the hydrophilic part of the molecule contains a positively and / or negatively charged ion, which may be a metal, i.e. a metal cation. Metal containing ionic surfactants are a more specific class of surfactant where the hydrophilic part of the molecule contains a positively charged metal ion, also referred to as a metal cation. The positive charge is understood to allow such metal-containing ionic surfactants to interact strongly with other charged molecules and surfaces. Accordingly, a metal containing ionic surfactant further comprises a hydrophobic group, or tail which is typically an oil-soluble hydrocarbon, and a hydrophilic head which contains the metal cation (“M”) and anionic functional group, alternatively described as an anion or soap, which together interact with water.

[0054] The hydrophobic (also known as the oleophilic or lipophilic) group is typically a hydrocarbon chain that confers oil-solubility to the surfactant and may have a molecular weight, Mn, of less than about 50000 g / mol and greater than about 50 g / mol. For example, the oleophilic / lipophilic group, or hydrocarbon chain, may have a molecular weight, Mn, of from any of greater than about 50 g / mol (or at least 50 g / mol) to about 50000 g / mol, from about 60 to about 20000 g / mol, from about 70 g / mol to about 5000 g / mol, from about 80 g / mol to about 1300 g / mol, from about 85 g / mol to about 1400 g / mol, in increasing order of preference. The surfactant may comprise more than one lipophilic portion, such as two, three, four, five and so on lipophilic portions. Separate lipophilic portions may typically be separated from one another by a non-lipophilic, non-oleophilic or hydrophilic portion of the surfactant, such as the hydrophilic or polar head group. In embodiments of each aspect of the present invention, at least one of (for example more than one of, e.g. two or more of, three or more of, four or more of or five or more of) the one or more lipophilic portions, up to and including all of the one or more lipophilic portions in the surfactant, individually (i.e. disregarding any other lipophilic portion in the molecule) or collectively (as between the one or more lipophilic portions in amolecule of the surfactant) may have a molecular weight or an average molecular weight, Mn, within one of the ranges as specified above. The lipophilic portion(s) of the ionic surfactant may be, or comprise linear, branched and / or cyclic; monomeric, oligomeric or polymeric; saturated, unsaturated or aromatic hydrocarbons.

[0055] Thus, the surfactant may comprise (e.g. as the lipophilic portion) an oil-soluble polymeric backbone, such as an olefin polymer, and may comprise one or more olefin polymers, functionalised with at least one polar functional group. The molecular weight of the olefin polymer may equate to (e.g. provide) the molecular weight of the lipophilic portion. As used herein, the term “polymer” (and commensurately the prefix “poly-”) includes molecules formed from at least 2 monomer repeating chemical units, preferably having at least about 3, 4, 5, 6, 7, 8, 9, or 10 monomer repeating chemical units and up to about 1000, 500, 300, 200, 100, 50, 40, 30 or 20 monomer repeating chemical units, including without limitation homopolymers, copolymers (typically at least about 4, 5, 6, 7, 8, 9 or 10 repeat units and up to about 1000, 500, 300, 200, 100, 50, 40, 30 or 20 repeat units) and block copolymers (also typically at least about 4, 5, 6, 7, 8, 9 or 10 repeat units and up to about 1000, 500, 300, 200, 100, 50, 40, 30 or 20 repeat units). Also as used herein, the terms “olefin polymer,” “poly(olefin),” “polyolefin” “poly(alkene)” and “polyalkene” “poly(alkylene)” and “polyalkylene” interchangeably mean polymers of any olefinic monomer unit, that is to say any monomer unit comprising at least one C=C bond (any alkene), and preferably refers to hydrocarbonaceous alkenes, in this sense meaning alkenes or olefins consisting of carbon atoms and hydrogen atoms, or alternatively stated alkenes with no, or substantially no, heteroatoms.

[0056] A preferred class of olefin polymers are polybutenes, specifically polyisobutenes (PIB) or poly-n-butenes (PNB), such as may be prepared by polymerization of a C4 refinery stream. Another preferred olefin polymer is polyisoprene. The poly(olefin), polybutene, polyisobutene, poly-n-butene or polyisoprene chain forming the lipophilic portion may typically have a molecular weight of greater than about 50 g / mol (or at least 50 g / mol) to about 50000 g / mol, from about 60 to about 20000 g / mol, from about 70 g / mol to about 5000 g / mol, from about 80 g / mol to about 1300 g / mol, from about 85 g / mol to about 1400 g / mol, in increasing order of preference.

[0057] Common types of metal containing ionic surfactants include metal salts of carboxylic acids (depicted in Structure 1) wherein R may be any linear, branched and / or cyclic; monomeric, oligomeric or polymeric; saturated, unsaturated or aromatic hydrocarbon of between about 6 and about 100 carbon atoms, preferably from 12 to 26 carbon atoms.

[0058]

[0059] Structure 1: Metal carboxylate

[0060] A further type of metal containing ionic surfactant includes the metal salts of organic sulfates (depicted in Structure 2) which may also be ethoxylated (depicted in Structure 3) wherein R may be any linear, branched and / or cyclic; monomeric, oligomeric or polymeric; saturated, unsaturated or aromatic hydrocarbon of between about 6 and about 100 carbon atoms, preferably from 12 to 26 carbon atoms, andx may be between about 1 and about 5, preferably between about 2 and about 3.

[0061]

[0062] Structure 2: Metal alkyl sulfate. Structure 3: Ethoxylated metal alkyl sulfate.

[0063] A further type of metal containing ionic surfactant includes the metal salts of organic sulfonates

[0064] (Structure 4) wherein R may be any linear, branched and / or cyclic; monomeric, oligomeric or polymeric; saturated, unsaturated or aromatic hydrocarbon of between about 6 and about 100 carbon atoms,

[0065] preferably from 12 to 26 carbon atoms. A preferred class of organic sulfonates are metal alkyl benzene sulfonates (Structure 4a) wherein R may be any linear, branched and / or cyclic; monomeric, oligomeric or polymeric; saturated, unsaturated or aromatic hydrocarbon of from about 6 to about 100 carbon atoms, preferably from about 8 to about 80 or more carbon atoms and more preferably from about 10 to about 60 carbon atoms. In some particularly preferred embodiments, R represents a linear, branched or polymeric hydrocarbon chain of between about 20 and about 40 carbon atoms.

[0066]

[0067] Structure 4: Metal alkyl sulfonate Structure 4a: Metal alkaryl sulfonate

[0068] A further type of metal containing ionic surfactant includes the metal salts of alkyl phenates (Structure 5) wherein R may be any linear, branched and / or cyclic; monomeric, oligomeric or polymeric; saturated, unsaturated or aromatic hydrocarbon of from about 4 to about 100 carbon atoms, preferably from 4 to 30 carbon atoms, more preferably from 6 to 18 carbon atoms, and even more preferably from 8 to 16 carbon atoms. A preferred class of alkyl phenate are the metal alkyl phenate condensates (Structure 6) wherein y is 0 to 10, preferably 1 to 8, more preferably 2 to 7, and even more preferably 3 to 6; A is a divalent

[0069] bridging group, and is preferably a hydrocarbyl linking group or sulfur, more preferably sulfur, where x is from about 1 to about 4; and R is any linear, branched and / or cyclic; monomeric, oligomeric or polymeric; saturated, unsaturated or aromatic hydrocarbon having from 4 to 30, preferably 6 to 18, and most

[0070] preferably 8 to 16 carbon atoms.

[0071]

[0072] Structure 5: Metal alkyl phenate. Structure 6: Metal alkyl phenate condensate.A further type of metal containing ionic surfactant includes the metal salts of alkyl salicylates (Structure 7) wherein R may be any linear, branched and / or cyclic; monomeric, oligomeric or polymeric; saturated, unsaturated or aromatic hydrocarbon of from about 6 to about 100 carbon atoms, preferably from about 8 to about 80 carbon atoms, more preferably from about 10 to about 60 carbon atoms, and even more preferably a mixture of linear, branched or polymeric hydrocarbon chains of from about 12 to about 30 carbon atoms.

[0073]

[0074] Structure 7: Metal alkyl salicylate.

[0075] In the ionic surfactant, including all of the above Structures, the metal (M in the above Structures) may be any metal ion having a charge n (e.g. n+ charge), preferably a single, doubly or triply charged metal ion, preferably a metal ion from group I or group II, more preferably selected from lithium, sodium, potassium, beryllium, magnesium, calcium, strontium, and mixtures thereof and even more preferably wherein the metal is selected from sodium, potassium, magnesium, calcium and mixtures thereof. Additionally, for a doubly charged metal ion, the metal cation may be a basic singly charged moiety MOH+or a neutral doubly charged moiety M2+or a mixture of the two.

[0076] In the ionic surfactant, the anion may be selected from carboxylate, hydrocarbyl-substituted carboxylate, alkyl-substituted carboxylate, sulfate, hydrocarbyl sulfate, alkyl sulfate, ethoxylated hydrocarbyl sulfate, ethyoxylated alkyl sulfate, sulfonate, hydrocarbyl sulfonate, alkyl sulfonate, hydrocarbaryl sulfonate, alkaryl sulfonate, phenate, hydrocarbyl phenate, alkyl phenate, oligomeric or polymeric bridged phenate, oligomeric or polymeric hydrocarbyl bridged phenate, oligomeric or polymeric alkyl phenate, salicylate, hydrocarbyl alkyl salicylate and mixtures thereof.

[0077] In all of the above Structures, R may be derived from one or more fatty acids, including mixtures of fatty acids, such as naturally-occurring fatty acids.

[0078] In all of the above Structures, the term “alk-” may be replaced with “hydrocarb-” such as the term “alkyl” being replaced with “hydrocarbyl” and the term “alkaryl” being replaced with “hydrocarbaryl”, and the “linear, branched and / or cyclic; monomeric, oligomeric or polymeric; saturated, unsaturated or aromatic hydrocarbon” may alternatively be described as a “hydrocarbonaceous moiety” or “linear, branched and / or cyclic; monomeric, oligomeric or polymeric; saturated, unsaturated or aromatic hydrocarbonaceous moiety.” In some embodiments, the total mass of ionic surfactant in the dispersion is at least 100g.

[0079] In selected embodiments, the at least one ionic surfactant is not, is other than or does not consist of (but may comprise) an ammonium salt of the reaction product of a polyisobutylene succinic acid with an organic amine or alkanolamine.

[0080] In selected embodiments, the at least one ionic surfactant is not, is other than, or does not consist of(but may comprise) an ammonium salt of the reaction product of a polyisobutylene succinic acid with N-Methyldiethanolamine, Monoethanolamine, 2-Amino-2-methyl-1 -propanol, Diethanolamine, Triethanolamine, Diethylethanolamine, Diisopropanolamine, Diglycolamine, 2-(Methylamino)ethanol, 2-(Dimethylamino)ethanol, 2-(Ethylami no)ethanol, (2-Hydroxyethyl)ethy lened iami ne, 1, 4-Pi perazi nediethanol, 3-Amino-1 -propanol, (±)-1-Amino-2-propanol, Tris(2-aminoethyl)amine, 2-Aminoethylpiperazine, 4-piperadinamine, 1-(Aminomethyl)piperidine, 4-(Aminomethyl)piperidine, 1 -Aminoethylpiperidine, 4-Aminoethylpiperidine, 4-Amino-1 -piperidineethanol, etc., 2-Morpholinoethylamine, 2-Morpholinopropylamine, etc., Piperazine (PZ) and its derivatives such as 1-(2-aminoethyl)piperazine (AEP), 1,4-piperazine diethanamine, 1 -Methylpiperazine, 2-Methylpiperazine, 2,5-Dimethylpiperazine, 1-Ethylpiperazine, 2-Ethylpiperazine, etc., and alkyl alcohol derivatives of piperazine including 1-(2-hydroxyethyl)piperazine (HEP), 1 -Piperazinepropanol, etc., Ethylenediamine (EDA); Diethylenetriamine (DETA); Triethylenetetramine (TETA); Tetraethylenepentamine (TEPA); Pentaethylenehexamine (PEHA); Hexaethyleneheptamine (HEHA) and so on; (and their polyolefin amine analogues, polypropylene amine analogues, polybutylene amine analogues, polypentylene amine analogues, polyhexylene amine analogues, etc. and so on); Propylene diamine, 1,3-propanediamine, Dipropylenetriamine, Butylenediamine, Isobutylene diamine, 1,3-butane diamine, Dibutylenetriamine, 1,4-Butane diamine, 1,5-Pentanediamine, 1,6-Hexanediamine, etc. and so on; and Polyethyleneimine (PEI) (linear or branched); Homopiperazine, 1,3-Diamino-2-propanol, N-Methyl-1,3-propanediamine, 2,2-Dimethyl-1,3-propanediamine, N, N-Dimethyl-1,3-propanediamine, N-Cyclohexyl-1,3-propanediamine, 2,2'-(1,2-Ethanediyldiimino)bis[ethanol], 1,4-Diaminocyclohexane, Guanidine, Bisfdimethylami noethyl) ether, Triethylethylenediamine, 1 H-1,2,4-Triazole, 3-Amino-1 H-1,2,4-Triazole, 2-Pyridinemethanamine, 2-Pyridineethanamine, 4-Aminopyridine, N, N-Diethyl-1,3-propanediamine, 1,3,5-Triazine, Melamine, o-Phenylenediamine, m- Phenylenediamine, p-Phenylenediamine, or mixtures thereof.

[0081] In selected embodiments, the at least one ionic surfactant is not, is other than, or does not consist of (but may comprise) an ammonium salt of the reaction product of polyisobutylene succinic acid with diethylethanolamine (DEAE), methyl diethanolamine (MDEA), triethanolamine (TEA), tetratethylenepentamine (TEPA) or PAM.

[0082] In selected embodiments, the at least one ionic surfactant is not, is other than, or does not consist of (but may comprise) an ammonium salt of the reaction product of a 1000 Mn PIBSA having a saponification number of 102 mgKOH / g with diethylethanolamine (DEAE), methyl diethanolamine (MDEA), triethanolamine (TEA), of a 1000Mn PIBSA with tetraethylenepentamine (TEPA), of a thermally-functionalised 450, 700 or 2300 Mn PIBSA with PAM or of a chloro-functionalised 950 or 2225 Mn PIBSA having a saponification number of 102 mgKOH / g with PAM.

[0083] In selected embodiments, the at least one ionic surfactant is not, is other than, or does not consist of (but may comprise) an ammonium salt of the reaction product of a 1000 Mn PIBSA having a saponification number of 102 mgKOH / g with diethylethanolamine (DEAE) (26g with 220g PIBSA, stirred in the presence of 46g base oil at 120°C for 3.5 hours), methyl diethanolamine (MDEA) (498g with 4505g PIBSA stirred in the presence of 3329g base oil at 120°C for 3.5 hours), triethanolamine (TEA) (54g with 396g PIBSA stirred in the presence of 368g base oil at 120°C for 3.5 hours), of a thermally-functionalised 10OOMnPIBSA with tetraethylenepentamine (TEPA), of a thermally-functionalised 450, 700 or 2300 Mn PIBSA with PAM or of a chloro-fu nctionalised 950 or 2225 Mn PIBSA having a saponification number of 102 mgKOH / g with PAM.

[0084] In selected embodiments, the at least one ionic surfactant is not, is other than, or does not consist of (but may comprise) an ammonium salt of the reaction product of a ch loro-fu nctionalised 1000 Mn PIBSA having a saponification number of 102 mgKOH / g with diethylethanolamine (DEAE) having a purity of at least 99% by mass (26g with 220g PIBSA, stirred in the presence of 46g base oil at 120°C for 3.5 hours), methyl diethanolamine (MDEA) having a purity of at least 99% by mass (498g with 4505g PIBSA stirred in the presence of 3329g base oil at 120°C for 3.5 hours), triethanolamine (TEA) having a purity of at least 99% by mass (54g with 396g PIBSA stirred in the presence of 368g base oil at 120°C for 3.5 hours), of a thermally-functionalised 1000Mn PIBSA with tetraethylenepentamine (TEPA), having a purity of at least 99%, of a thermally-functionalised 450, 700 or 2300 Mn PIBSA having a saponification number of 102 mgKOH / g with PAM having a kinematic viscosity at 40°C of 110 cSt, a water content of 1 wt.% and a nitrogen content of 36 wt.% or of a chloro-functionalised 950 or 2225 Mn PIBSA having a saponification number of 102 mgKOH / g with PAM having a kinematic viscosity at 40°C of 110 cSt, a water content of 1 wt.% and a nitrogen content of 36 wt.%.

[0085] In some embodiments, being any of the selected embodiments above, the at least one ionic surfactant is not, is other than, or does not consist of (but may in any event comprise) an ammonium salt as defined, only wherein the dispersion is formed by:

[0086] 1. overhead stirring of the ionic surfactant and the base oil at 200 RPM and a temperature of 60°C for 30 minutes, and then;

[0087] 2. adding:

[0088] a. from 10 to 60 wt.% monoethanolamine having a purity of 99% by mass and stirring with an emulsor screen at a temperature of 70°C for 6 hours, wherein the ammonium salt is of the reaction product of PIBSA with DEAE, MDEA or TEA and wherein the dispersion contains 30 wt.% monoethanolamine if the ammonium salt is of the reaction product of PIBSA with DEAE, MDEA TEA or MEA;

[0089] b. 31.58 wt.% 2-amino-2-methyl-1 -propanol having a purity of 95% with 5% water impurity and stirring with an emulsor screen at a temperature of 50°C for 6 hours, wherein the ammonium salt is of the reaction product of PIBSA with DEAE or 2-amino-2-methyl-1 -propanol; or

[0090] c. 13.5 wt.% 2-amino-2-methyl-1 -propanol having a purity of 95% with 5% water impurity, 6.5 wt.% piperazine having a purity of 99%, and 30 wt.% water and stirring with an emulsor screen at a temperature of 70°C for 6 hours, wherein the ammonium salt is of the reaction product of PIBSA with DEAE, 2-amino-2-methyl-1 -propanol or piperazine;

[0091] d. from 0 to 70 wt.% tetraethylenepentamine and stirring with an emulsor screen at a temperature of 90°C for 6 hours, wherein the ammonium salt is of the reaction product of PIBSA with tetraethylenepentamine or PAM and wherein the dispersion contains 30wt.% tetraethylenepentamine if the ammonium salt is of the reaction product of the 2225, 950, 700 or 450 Mn PIBSA with PAM, or of 1000 Mn PIBSA with tetraethylenepentamine;

[0092] e. 30 wt.% PAM and stirring with an emulsor screen at a temperature of 90°C for 6 hours, wherein theammonium salt is of the reaction product of the 2300 Mn PIBSA with PAM;

[0093] f. 30 wt.% tetraethylenepentamine and 10 wt.% water and stirring with an emulsor screen at a temperature of 70°C for 6 hours, wherein the ammonium salt is of the reaction product of the 2300 Mn PIBSA with PAM or tetraethylenepentamine;

[0094] g. 30 wt.% 1-(2-aminoethyl)piperazine having a purity of 99% and stirring with an emulsor screen at a temperature of 70°C for 6 hours, wherein the ammonium salt is of the reaction product of the 2300 Mn PIBSA with PAM or 1-(2-aminoethyl)piperazine;

[0095] h. 30 wt.% 1-(2-aminoethyl)piperazine having a purity of 99% and 10 wt.% water and stirring with an emulsor screen at a temperature of 90°C for 6 hours, wherein the ammonium salt is of the reaction product of the 2300 Mn PIBSA with PAM or 1-(2-aminoethyl)piperazine;

[0096] i. 30 wt.% 1 -(2-hyd roxyethy l)p iperazi ne having a purity of 99% and stirring with an emulsor screen at a temperature of 90°C for 6 hours, wherein the ammonium salt is of the reaction product of the 2300 Mn PIBSA with PAM or 1-(2-hydroxyethyl)piperazine; and then;

[0097] 3. immediately decanting and cooling to room temperature; and

[0098] 4. producing less than 1kg of dispersion.

[0099] Additional Surfactants

[0100] Optionally, compositions associated with the present invention may comprise one or more additional surfactants, or alternatively stated may comprise one additional surfactant or a plurality of additional surfactants. When present, the additional surfactant(s) may therefore be considered to be in addition to the base oil, organic base and ionic surfactant comprised within compositions associated with the present invention, and the additional surfactant may comprise at least one first additional surfactant and / or at least one second additional surfactant.

[0101] Any first additional surfactant(s) may be present in a greater quantity by weight than any other additional surfactant or surfactants, such as any said second additional surfactant(s). Where present, any said second additional surfactant(s), and / or any further surfactants, may be present in a lesser quantity by weight than any said first additional surfactant(s), separately or collectively.

[0102] As herein described, any surfactant may also be described as an emulsifier and / or as a dispersant, e.g. a first additional surfactant and a second additional surfactant may also be described as a first emulsifier and second emulsifier or as a first dispersant and a second dispersant. Also as herein described, a dispersant is an additive whose primary function is to hold oil-insoluble substances in suspension (in other words, a dispersant holds oil-insoluble substances in dispersion). For example, a dispersant maintains in suspension oil-insoluble substances, such as oil-insoluble components and in the context of the present invention, the organic base, thus preventing or reducing flocculation and resultant precipitation or deposition on surfaces. Dispersants typically comprise a lipophilic or oleophilic portion (such as a hydrocarbon chain or hydrocarbon moiety) and a hydrophilic, e.g. polar, portion, the polarity being derived from the inclusion of heteroatoms, preferably heteroatoms covalently bonded to the lipophilic or oleophilic portion, and more preferably oxygen and / or nitrogen atoms. Accordingly, any said first additional surfactant(s) (and any said second additional surfactant(s)) typically comprise a polar head group, the polarity being derived from the inclusion of heteroatoms, preferably heteroatoms covalently bonded, directlyor indirectly, to the oleophilic / lipophilic portion (e.g. hydrocarbon chain), and more preferably where the heteroatoms are oxygen atoms, nitrogen atoms, or mixtures thereof.

[0103] First additional surfactant(s)

[0104] The oleophilic or lipophilic group of any said first additional surfactant(s) may comprise, or be, a hydrocarbon chain that confers oil-solubility to the surfactant and may have a molecular weight, Mn, of greater than 450 g / mol, such as at least 500 g / mol. For example, the oleophilic / lipophilic group, or hydrocarbon chain, may have a molecular weight, Mn, of from any of greater than 450 g / mol, at least 500 g / mol, at least 550 g / mol, at least 600 g / mol, at least 650 g / mol or at least 700 g / mol to any of 50000 g / mol, 40000 g / mol, 30000 g / mol, 20000 g / mol, 10000 g / mol, 5000 g / mol, 2500 g / mol, 1500 g / mol or 1300 g / mol, such as from greater than about 450 g / mol (or at least 500 g / mol) to about 50000 g / mol, from about 500 to about 20000 g / mol, from about 550 g / mol to about 5000 g / mol, from about 600 g / mol to about 2500 g / mol, from about 650 g / mol to about 1500 g / mol, or from about 700 g / mol to about 1300 g / mol, in increasing order of preference. Any said first additional surfactant(s) may comprise more than one lipophilic portion, such as two, three, four, five and so on lipophilic portions. Separate lipophilic portions may typically be separated from one another by a non-lipophilic, non-oleophilic or hydrophilic portion of the surfactant, such as the hydrophilic or polar head group. In embodiments of each aspect of the present invention, at least one of (for example more than one of, e.g. two or more of, three or more of, four or more of or five or more of) the one or more lipophilic portions, up to and including all of the one or more lipophilic portions in any said first additional surfactant(s), individually (i.e. disregarding any other lipophilic portion in the molecule) or collectively (as between the one or more lipophilic portions in a molecule of any said first additional surfactant(s)) may have a molecular weight or an average molecular weight, Mn, within one of the ranges as specified above. The lipophilic portion(s) of any said first additional surfactant(s), or any additional surfactant(s) may be, or comprise: linear, branched and / or cyclic; monomeric, oligomeric or polymeric; saturated, unsaturated or aromatic hydrocarbons.

[0105] Thus, any said first additional surfactant(s) may comprise (e.g. as the lipophilic portion) an oil-soluble polymeric backbone, such as an olefin polymer, and may comprise one or more olefin polymers, functionalised with at least one polar functional group. The molecular weight of the olefin polymer may equate to (e.g. provide) the molecular weight of the lipophilic portion. The preferred surfactants, particularly those with an oleophilic group having a molecular weight, Mn, within the ranges above, may have a hydrophilic-lipophilic balance (HLB) value, which may be calculated using Griffin’s Method, or may otherwise be a published value, of from about 0.1 to about 8, such as from about 0.5 to about 7, more preferably from about 0.5 to about 6, such as from about 0.5 to about 5.5 or from about 1 to about 5. As used herein, the term “polymer” (and commensurately the prefix “poly-”) includes molecules formed from at least 2 monomer repeating chemical units, preferably having at least about 3, 4, 5, 6, 7, 8, 9, or 10 monomer repeating chemical units and up to about 1000, 500, 300, 200, 100, 50, 40, 30 or 20 monomer repeating chemical units, including without limitation homopolymers, copolymers (typically at least about 4, 5, 6, 7, 8, 9 or 10 repeat units and up to about 1000, 500, 300, 200, 100, 50, 40, 30 or 20 repeat units) and block copolymers (also typically at least about 4, 5, 6, 7, 8, 9 or 10 repeat units and up to about 1000, 500, 300, 200, 100, 50, 40, 30 or 20 repeat units). Also as used herein, the terms “olefin polymer,” “poly(olefin),”“polyolefin” “poly(alkene)” and “polyalkene” “poly(alkylene)” and “polyalkylene” interchangeably mean polymers of any olefinic monomer unit, that is to say any monomer unit comprising at least one C=C bond (any alkene), and preferably refers to hydrocarbonaceous alkenes, in this sense meaning alkenes or olefins consisting of carbon atoms and hydrogen atoms, or alternatively stated alkenes with no, or substantially no, heteroatoms.

[0106] A preferred class of olefin polymers are polybutenes, specifically polyisobutenes (PIB) or poly-n-butenes, such as may be prepared by polymerization of a C4 refinery stream. Another preferred olefin polymer is polyisoprene. The poly(olefin), polybutene, polyisobutene, poly-n-butene or polyisoprene chain forming the lipophilic portion may typically have a molecular weight of greater than about 450 g / mol, such as at least about 500 g / mol, and preferably has a molecular weight in the range of from greater than about 450 g / mol (or at least 500 g / mol) to about 50000 g / mol, from about 500 to about 20000 g / mol, from about 550 g / mol to about 5000 g / mol, from about 600 g / mol to about 2500 g / mol, from about 650 g / mol to about 1500 g / mol, or from about 700 g / mol to about 1300 g / mol, in increasing order of preference.

[0107] Additional surfactants may include, for example, derivatives of long chain hydrocarbon-substituted carboxylic acids, examples being derivatives of high molecular weight hydrocarbyl-substituted succinic acid. Typically, a hydrocarbonaceous polymeric material, such as polyisobutene or polyisoprene (but any olefin polymer, copolymer, or block co-polymer which is capable of functionalisation by reaction with maleic acid or anhydride to make a succinate), is reacted with an acylating group (such as maleic acid or anhydride) to form a hydrocarbon-substituted succinic acid (succinate) or succinic anhydride.

[0108] In some preferred embodiments where present, any said first additional surfactant(s) may comprise, consist of, or be, one or more non-ionic surfactants, which may be desirably selected from one or more olefin polymers, functionalised with at least one polar functional group, such as an organic amine, alcohol, or alkanolamine. In some preferred embodiments, the at least one surfactant comprises the reaction product or mixture of a succinic acid and an organic amine and / or organic alcohol, and particularly preferred surfactants comprise the reaction product or mixture of a poly(olefin) succinic acid and / or poly(olefin) succinic anhydride (such as poly(isobutene) succinic acid) or poly(isobutene) succinic anhydride, “PIBSA”) with an organic amine, more preferably where said organic amine additionally comprises a hydroxy group (such as in an alkanolamine).

[0109] A preferred group of additional surfactants is constituted by hydrocarbon-substituted succinimides and / or succinates, made, for example, by reacting the above acids (or derivatives) with an oxygencontaining or nitrogen-containing compound, advantageously an organic amine, alcohol or alkanolamine (being both an organic alcohol and organic amine). In some preferred embodiments, the organic amine comprises primary amine functionality (e.g. is a primary amine) or may be a primary, secondary or tertiary alkanolamine, in this sense meaning an alkanolamine with primary, secondary or tertiary amine functionality. In some further preferred embodiments where the nitrogen-containing compound is an alkanolamine, the amine functionality of the alkanolamine is tertiary, including entirely tertiary, such that there may be no primary or secondary amine functionality in the alkanolamine. The nitrogen-containing compound may be the same as or different to the organic base.

[0110] Examples of oxygen-containing compounds or organic alcohols include lactones (alternatively describedthemselves as cyclic condensation products of organic acids with alcohols), polyols (such as ethylene glycol, glycerol, sorbitol, etc.), dehydrated polyols (such as 1,5-anhydroglucitol, 1,4:3,6-dianhydro-D-glucitol, sorbitan, etc.), sugars (such as sucrose, glucose, fructose, galactose, etc.), polysaccharides, etc. In some further embodiments the nitrogen-containing compound is a polyether amine based on either ethylene oxide (EO), propylene oxide (PE) or a mixture of the two. Polyether amines have the general structure given in structure A1 where X is between 1 and 50, Y is between 1 and 50, and Ri is either H or a methyl group, R2 is either H or a methyl group and R3 is either a primary amine or methyl group.

[0111]

[0112] Structure A1

[0113] Commercial examples of polyether amines include the Jeffamine series sold by the Huntsman corporation. In the Jeffamine nomenclature, the number indicates the molecular weight. Examples of commercially available and useful Jeffamines include polyoxypropene diamines Jeffamine D-230 and D-400, and polyether diamines Jeffamine D-148, Jeffamine D-403, Jeffamine EDR-148, Jeffamine EDR-192, Jeffamine ED-600, and the polyether monoamine Jeffamine M-600.

[0114] Examples of such amines and alkanolamines that generally may be comprised in the nitrogencontaining compound include: N-Methyldiethanolamine, N-(2-hydroxyethyl)ethylenediamine, Monoethanolamine, 2-Amino-2-methyl-1 -propanol, Diethanolamine, 1 -Piperazineethanol, Triethanolamine, Diethylethanolamine, Diisopropanolamine, Diglycolamine, 2-(Methylamino)ethanol, 2-(Dimethylamino)ethanol, 1-Piperazineethanamine, 2-(Ethylamino)ethanol, (2-Hydroxyethyl)ethylenediamine, 1,4-Piperazinediethanol, Diethylenetriamine, 3-Amino-1 -propanol, Triethylenetetramine, (±)-1-Amino-2-propanol, Tetraethylenepentamine, 2, 2’, -(1,2-ethanediyldiimino)bis[ethanol], Tris(2-aminoethyl)amine, (±)-2-Amino-1 -propanol, 2-Aminoethylpiperazine, Pentaethylenehexamine, Hexaethyleneheptamine, 3,6-dioxaoctamethylenediamine, tetraethylene glycol diamine, or mixtures thereof; preferred nitrogen-containing compounds are selected from N-(2-hydroxyethyl)ethylenediamine, Monoethanolamine, Diethanolamine, 1 -Piperazineethanol, Diethylethanolamine, 1-Piperazineethanamine, Tetraethylenepentamine (TEPA), Pentaethylenehexamine (PEHA), Hexaethyleneheptamine (HEHA), etc., or mixtures thereof; and a more preferred nitrogencontaining compound is Diethylethanolamine (DEAE). It is of particular convenience for the nitrogencontaining compound (organic amine or alkanolamine) to be the same as the organic base, so by way of non-limiting example, both the organic base forming a component of the dispersion and the organic amine both may be Monoethanolamine, both may be Diethanolamine, both may be 1 -Piperazineethanol, both may be Diethylethanolamine, both may be 1-Piperazineethanamine or both may be Tetraethylenepentamine (TEPA). Where a mixture of nitrogen-containing compounds (e.g. organic amines or alkanolamines) is used in the surfactant, the same mixture may be used as the organic bases in the dispersion, and commensurately where a mixture of organic bases is used in the dispersion, the same mixture may beused as the nitrogen-containing compounds (e.g. organic amines or alkanolamines) in the surfactant. It is to be understood that the surfactant may further react with the organic base (particularly where the organic base comprises primary amine functionality while the polar head, such as organic amine, in the surfactant does not) within the compositions and dispersions contemplated by the present invention, whether before, while or after being introduced to the systems of the present invention, and whether before or during utilisation in the methods, processes and uses of the present invention. Accordingly, by way of non-limiting example, an organic base comprising primary amine functionality utilised in combination with a PIBSA-alkanolamine surfactant (derived from an alkanolamine without primary amine functionality) may displace the alkanolamine in the surfactant, resulting in (typically a small portion of) the organic base forming the surfactant head group in whole or in part, and the organic amine becoming a (typically minor) component of the remaining organic base.

[0115] In further preferred embodiments, the surfactant is, or comprises, the reaction product of a polyisobutene succinic acid and an amine that also comprises a hydroxy group, e.g. an alkanolamine, notably selected from N-Methyldiethanolamine, Monoethanolamine, Diethanolamine, 1 -Piperazineethanol, Diethylethanolamine, 1-Piperazineethanamine, Tetraethylenepentamine, such as Diethylethanolamine (DEAE) and especially wherein the alkanolamine is diethylethanolamine (DEAE), i.e. the surfactant is, or comprises, the reaction product of a polyisobutene succinic acid and diethylethanolamine (DEAE). In either preferred embodiment, the polyisobutene chain preferably may have a molecular weight, Mn, of from greater than about 450 g / mol (or at least 500 g / mol) to about 50000 g / mol, from about 500 to about 20000 g / mol, from about 550 g / mol to about 5000 g / mol, from about 600 g / mol to about 2500 g / mol, from about 650 g / mol to about 1500 g / mol, or from about 700 g / mol to about 1300 g / mol, in increasing order of preference. The polyisobutene may be replaced by polyisoprene.

[0116] Accordingly, a particularly preferred surfactant comprises the reaction product or mixture of polyisobutene succinic anhydride (shown as Structure A2), and / or polyisobutene succinic acid (shown as Structure A3):

[0117]

[0118] in either case wherein n is a positive integer from about 7 to about 900, with one or more organic amines selected from N-Methyldiethanolamine, Monoethanolamine, Diethanolamine, 1 -Piperazineethanol, Diethylethanolamine, 1-Piperazineethanamine, Tetraethylenepentamine, such as Diethylethanolamine (DEAE, shown as Structure A4):

[0119]

[0120] Structure A4wherein preferably n is from about 7 to about 900, more preferably from about 8 to about 350, even more preferably from about 9 to about 90 and even more preferably still from about 10 to about 45, even more preferably still from about 11 to about 27, such as from about 12 to about 23.

[0121] In some further preferred embodiments, any said first additional surfactant(s) may comprise or consist of the reaction product of a polyolefin with maleic anhydride to produce a functionalised polyolefin succinic anhydride which is further reacted with an organic amine to produce a polyolefin succinic imide or amide. In some embodiments, the polyolefin comprises, or is, PIB, and the organic amine comprises, or is, PAM orTEPA.

[0122] Polyolefins are typically produced with a terminal olefin. Depending on the location of the terminal olefin, two routes to functionalisation using maleic anhydride are possible. For example, PIB rich in terminal olefins with a high proportion (over about 75%) of “vinylidene” terminal olefin are suitable for functionalisation with maleic anhydride using the thermal “ene” reaction and are thus termed thermal, or high-reactivity (HR), PIB (HR-PIB). By way of non-limiting example, commercially available examples of thermal or HR 1000 number average molecular weight (Mn) PIB include Glissopal 1000 produced by BASF, and TCP 595 produced by TPC group. PIB rich in other terminal olefins are suitable for functionalisation using chlorine gas via a Diels-Alder reaction with maleic anhydride and are termed “conventional” PIB. By way of non-limiting example, commercially available examples of 1000 Mnconventional PIB include PB950 from DL Chemical, and POLYBUT10 from YPF. Higher and lower MnHR and conventional PIB are available from the same suppliers. Functionalisation with maleic anhydride by either route (thermal “ene” or chloro Diels-Alder) may result in a number of succinic anhydride functional groups per PIB molecule, the precise average amount being termed the “Functionality” or “Fn” which can be determined according to the following formula (I):

[0123] Fn=(SAPxMn)[(1122xA. I.)-(SAPxMW)] (I)

[0124] wherein SAP is the saponification number (i.e., the number of milligrams of KOH consumed in the complete neutralization of the acid groups in one gram of the succinic-containing reaction product, as determined according to ASTM D94); Mnis the number average molecular weight of the starting olefin polymer (e.g. polybutylene); A. I. is the percent active ingredient of the succinic-containing reaction product; and MW is the molecular weight of the dicarboxylic acid-producing moiety (98 for maleic anhydride). A value for Fn less than or equal to 1.1 (or 1.10) is referred to as “low Fn PIBSA”. Fn above 1.1 (or 1.10) is referred to as “high Fn PIBSA”. The PIBSA so produced is further reacted with an amine in a process termed Amination. Primary amines are the most reactive, and so the resulting PIBSA-derived dispersants are further characterised by the molar ratio of succinic anhydride functional groups to primary amines, which is termed the “Coupling Ratio” or CR. PIBSA-derived dispersants with a coupling ratio less than or equal to 1 (or 1.0) are termed “Low CR dispersants”. PIBSA-derived dispersants with a coupling ratio above 1 (or 1.0) are termed “High CR dispersants”.

[0125] Preferred surfactants comprise the reaction product or mixture of a PIB (e.g. polyisobutylene) succinic acid or PIB (e.g. polyisobutylene) succinic anhydride, (each of which may be referred to as “PIBSA”) with an organic amine, where the organic amine contains at least one primary amine group, or at least one secondary amine group, or at least one hydroxyl functional group, or combinations thereof. Examples ofsuch organic amines include; 4-piperadinamine, 1 -(Aminomethyl)piperidine, 4-(Aminomethyl)piperidine, 1-Aminoethylpiperidine, 4-Aminoethylpiperidine, 4-Amino-1 -piperidineethanol, etc., 2-Morpholinoethylamine, 2-Morpholinopropylamine, etc., Piperazine (PZ) and its derivatives such as 1-(2-aminoethyl)piperazine (AEP), 1,4-piperazine diethanamine, 2-Piperazineethanamine, 1 -Methylpiperazine, 2-Methylpiperazine, 2,5-Dimethylpiperazine, 1 -Ethylpiperazine, 2-Ethylpiperazine, etc., and alkyl alcohol derivatives of piperazine including 1-(2-hydroxyethyl)piperazine (HEP), 2-Piperazineethanol, 1 -Piperazinepropanol, etc., Ethylenediamine (EDA); Diethylenetriamine (DETA); Triethylenetetramine (TETA); Tetraethylenepentamine (TEPA); Pentaethylenehexamine (PEHA); Hexaethyleneheptamine (HEHA) and so on; and their polyolefin amine analogues (including without limitation polypropylene amine analogues, polybutylene amine analogues, polypentylene amine analogues, polyhexylene amine analogues, etc. and so on); Propylene diamine, 1,3-propanediamine, Dipropylenetriamine, Butylenediamine, Isobutylene diamine, 1,3-butane diamine, Dibutylenetriamine, 1,4-Butane diamine, 1,5-Pentanediamine, 1,6-Hexanediamine, etc. and so on; and Polyethyleneimine (PEI) (which may be either linear or branched and is preferably branched);

[0126] Homopiperazine, 1,3-Diamino-2-propanol, (2-Hydroxyethyl)ethylenediamine, Tris(2-aminoethyl)amine, N-Methyl-1,3-propanediamine, 2, 2-Dimethyl- 1,3-propanediamine, N, N-Dimethyl-1,3-propanediamine, N-Cyclo hexyl- 1,3-propanediamine, 2, 2'-( 1, 2- Eth anedi yl di imi no) bis[eth anol], 1,4-Diaminocyclohexane, Guanidine, Bis(dimethylaminoethyl) ether, Triethylethylenediamine, 1 H-1,2,4-Triazole, 3-Amino-1 H-1,2,4-Triazole, 2-Pyridinemethanamine, 2-Pyridineethanamine, 4-Aminopyridine, N, N-Diethyl-1,3-propanediamine, 1,3,5-Triazine, Melamine, o-Phenylenediamine, m- Phenylenediamine, p-Phenylenediamine, etc., and mixtures of such amines.

[0127] Preferably, the organic amine is; 1-(2-aminoethyl)piperazine (AEP), 2-Piperazineethanamine, Tris(2-aminoethyl)amine, 1-(2-hydroxyethyl)piperazine (HEP), 1,3-Diamino-2-propanol, Triethylenetetramine (TETA); Tetraethylenepentamine (TEPA); Pentaethylenehexamine (PEHA); Hexaethyleneheptamine (HEHA); PAM; H-PAM or mixtures of such organic amines, more preferable organic amines include those selected from; 1-(2-aminoethyl)piperazine (AEP), Tetraethylenepentamine (TEPA); PAM; H-PAM or mixtures of such organic amines, and even more preferable organic amines include tetraethylenepentamine (TEPA) or PAM.

[0128] It is of particular convenience for the organic amine to be the same material as the organic base, so by way of non-limiting example, the organic base (e.g. forming a component of the dispersion or composition) and the organic amine (e.g. of the surfactant) both may be 1 -Aminoethylpiperazine, or both may be TEPA, or both may be selected from PAM or H-PAM, such as both being PAM or both being H-PAM. Where a mixture of nitrogen-containing compounds (e.g. organic amines or polyalkyl amines) is used in the surfactant, the same mixture may be used as the organic bases in the dispersion, and commensurately where a mixture of organic bases is used in the dispersion, the same mixture may be used as the nitrogencontaining compounds (e.g. organic amines or polyalkyl amines) in the surfactant. In further preferred embodiments, the surfactant is, or comprises, the reaction product of a PIB succinic acid and a polyamine such as 1-(2-aminoethyl)piperazine (AEP), Tetraethylenepentamine (TEPA); or PAM.

[0129] Accordingly, a particularly preferred surfactant comprises the reaction product or mixture of PIB succinic anhydride and / or PIB succinic acid according to the previously described Structures 2 and 3, ineither case wherein preferably n is a positive integer from about 7 to about 900, with one or more organic amines selected from 1-Piperazineethanamine, Tetraethylenepentamine (TEPA), PAM or H-PAM, (preferably tetraethylenepentamine (TEPA) or PAM), wherein preferably n is from about 7 to about 900, more preferably from about 8 to about 350, even more preferably from about 9 to about 90 and even more preferably still from about 10 to about 45, even more preferably still from about 11 to about 27, such as from about 12 to about 23.

[0130] Optionally, where the surfactant comprises one or more primary or secondary amines, additional functionality may be added through the process known as capping. Capping the dispersant involves posttreatment by a reaction with one or more of any of a variety of reactive agents; so-called “capping agents.” Among these are urea, aldehydes, ketones, carboxylic acids, hydrocarbon-substituted succinic anhydrides, maleic anhydride, epoxides or carbonate esters such as ethylene carbonate which may be used individually or in any combination to cap the surfactant. Capping can have multiple advantages such as passivating reactive moieties and / or adding or removing polarity from the hydrophilic portion of the surfactant, thereby altering the HLB value. The HLB value can be modified in this way by partial or complete capping on the head group with a selected capping agent.

[0131] In some embodiments, any one or more of said first additional surfactant(s) may be present in the dispersion (or composition), individually or collectively, in an amount of from about 0.1% to about 10%, from about 0.2% to about 9.5%, from about 0.5% to about 9%, from about 1 % to about 8%, from about 1.5% to about 7%, from about 1.7% to about 6% or from about 2% to about 4.5%, such as about 2.2% to about 4%, or about 2.5% to about 3%, each by weight on an active basis.

[0132] Second additional surfactant(s)

[0133] In addition or alternatively to any said first additional surfactant(s), at least one second additional surfactant (which may be described as a complementary surfactant) may be present in the compositions contemplated by the present invention. Any said second additional surfactant(s) may be a different surfactant to any said first additional surfactant(s), if both are present. Any said second additional surfactant(s) may be present in a lesser quantity by weight than any said first additional surfactant(s). Any said second additional surfactant(s) may be selected from the group of surfactants described above in relation to any said first additional surfactant (including without limitation as described by Structures A2, A3 and A4), provided that, where both present, any said second additional surfactant(s) may differ in at least one feature from any said first additional surfactant(s), or any said second additional surfactant(s) may be a different type of surfactant than any said first additional surfactant(s). By way of non-limiting examples, any said second additional surfactant(s) may comprise a different oleophilic / lipophilic portion (e.g. hydrocarbon chain) and / or a different hydrophilic head group to any said first additional surfactant(s). Additionally, or alternatively, any said second additional surfactant(s) may comprise a lower molecular weight oleophilic / lipophilic portion (or hydrocarbon chain) than previously described in relation to any said first additional surfactant(s).

[0134] Any said second additional surfactant(s) may typically comprise a polar head group, the polarity being derived from the inclusion of heteroatoms, preferably heteroatoms covalently bonded, directly or indirectly, to the oleophilic / lipophilic portion (e.g. hydrocarbon chain), and more preferably where the heteroatoms areoxygen atoms, nitrogen atoms, or mixtures thereof. Where present, the lower molecular weight hydrocarbon chain is an oleophilic group that accordingly confers modest oil-solubility to any said second additional surfactant(s) compared with any said first additional surfactant(s).

[0135] Accordingly, any said second additional surfactant(s) may have one or more lipophilic portions having a molecular weight less than the molecular weight of the one or more lipophilic portions of any said first additional surfactant(s), or having a molecular weight, Mn, of less than about 50000 g / mol, less than about 40000 g / mol, less than about 30000 g / mol, less than about 20000 g / mol, less than about 10000 g / mol, less than about 5000 g / mol, less than about 2500 g / mol, less than about 2000 g / mol, less than about 1500 g / mol, less than about 1300 g / mol, less than about 1000 g / mol or less than about 700 g / mol. Preferred ranges for the molecular weight of the one or more lipophilic portions of any said second additional surfactant(s) include from about 100 g / mol to about 1500 g / mol, more preferably from about 120 g / mol to about 1300 g / mol, and even more preferably from about 150 g / mol to less than about 700 g / mol, such as a molecular weight from about 100 to less than about 400 g / mol, from about 120 to about 300 g / mol, from about 120 (or 130) to about 250 g / mol, or from about 140 to about 250 g / mol, in increasing order of preference. Any said second additional surfactant(s) may comprise more than one lipophilic portion, such as two, three, four, five and so on lipophilic portions. Separate lipophilic portions may typically be separated from one another by a non-lipophilic, non-oleophilic or hydrophilic portion of the surfactant, such as the hydrophilic or polar head group. In some embodiments of each aspect of the present invention, at least one of (for example more than one of, e.g. two or more of, three or more of, four or more of or five or more of and so on) the one or more lipophilic portions, up to and including all of the one or more lipophilic portions, individually (i.e. disregarding any other lipophilic portion in the molecule) or collectively (as between the one or more lipophilic portions in a molecule, e.g. a single molecule, of any said second additional surfactant(s)) may have an average molecular weight, Mn, within one of the ranges as specified above. The lipophilic portion(s) of any said second additional surfactant(s), or any additional surfactant(s) may be, or comprise linear, branched and / or cyclic; monomeric, oligomeric or polymeric; saturated, unsaturated or aromatic hydrocarbons.

[0136] Thus, any said second additional surfactant(s) may comprise an oil-soluble backbone, functionalised with at least one polar functional group. Preferred examples of said second additional surfactants, particularly those with an oleophilic group having a molecular weight within the ranges above, may be predominantly oil-soluble or predominantly water soluble. In some preferred embodiments, any said second additional surfactant(s) may comprise, consist of, or be, one or more non-ionic surfactants.

[0137] A preferred class of hydrocarbon chain (lipophilic portion) in any said second additional surfactant(s) are those derived from commonly occurring fatty acids and fatty alcohols with carbon chain lengths in the range of from about 8 to about 26 carbon atoms, for example from about 8 to about 22 carbon atoms, from about 10 to about 18 carbon atoms, or from about 12 to about 18 carbon atoms, in increasing order of preference. Another preferred class of hydrocarbon solubilizing group (lipophilic portion) consists of alkyl-substituted para-benzene derivatives with the total number of carbon atoms in the range of from about 8 to about 26 carbon atoms. Another preferred class of hydrocarbon solubilizing group (lipophilic portion) consists of branched or linear alkanes, with alkyl chain lengths in the range of from about 8 to about 26 carbon atoms.In all the above preferred classes the hydrocarbon solubilizing group (lipophilic portion) preferably has a molecular weight of from about 100 to about 400 g / mol, from about 120 to about 300 g / mol, from about 120 to about 250 g / mol, or from about 140 to about 250 g / mol, in increasing order of preference.

[0138] Such lipophilic portions as detailed in relation to any said second additional surfactant(s) may be described as a low molecular weight hydrocarbon, or low molecular weight hydrocarbon chain. Such a low molecular weight hydrocarbon may have a carbon chain length in the range of from about 8 to about 26 carbon atoms and is typically functionalized with either an alkene, alcohol, carboxylic acid or amine group, so as to facilitate further functionalisation with a hydrophilic head group to create the finished dispersant. Some preferred second additional surfactants may have a hydrophilic-lipophilic balance (HLB) value, which may be calculated using Griffin’s Method, or may otherwise be a published value, of from about 0.1 to about 17, such as from about 1.8 to about 16, more preferably from about 3 to about 10, such as from about 3 to about 6 or from about 3 to about 5. In some preferred embodiments, and in particular combination with the presence of water in the composition (e.g. in the internal phase), a higher HLB second additional surfactant may be preferable. In such cases, an HLB value of between about 10 and about 17 may be desirable, such as from any of about 10, about 11, about 12, about 13 or about 14 to about 16 or about 17, such as between about 14 and about 16.

[0139] In some embodiments, the low molecular weight hydrocarbon is an alkane, alkene or aromatic carboxylate, functionalised with poly-ethoxylate units to create a surfactant of Structure A5, wherein m is between 2 and about 24 and Ri is a hydrocarbon moiety, which may be a straight chain, cyclic or branched moiety, further optionally containing saturated, mono-unsaturated, poly-unsaturated or aromatic moieties with carbon chain length C10 to C24. Commercial examples include Croda Brij L series, based on the lauric acid wherein the Ri molecular weight is 155 g / mol, for example Brij L4 and Brij L23 for which m is 4 and 23, respectively. Other examples from Croda Brij range include Brij C series, Brij S series and Brij O series based on cetylic (palmitic) acid (C16, Ri molecular weight is 211 g / mol), Stearic acid (C18, Ri molecular weight is 239 g / mol) and the mono-unsaturated oleic acid (C18: 1, Ri molecular weight is 237 g / mol) hydrocarbons, for example Brij 020 for which in Structure A5 m=20 and Brij 010 for which in Structure A5 m=10, etc.:

[0140]

[0141] Structure A5

[0142] In some embodiments, the low molecular weight hydrocarbon may be an alkane or alkene which additionally may be a primary or secondary alcohol, for example such that the surfactant is based on a secondary alcohol to create a surfactant of the general structure depicted by Structure A6, wherein x+y is between 2 and 6 and m is between 1 and 70. Commercial examples include the Dow Tergitol 15-S-m series for which in Structure A6 x+y=6 and m is between 5 and 40:

[0143] Structure A6

[0144]

[0145] In some embodiments, the low molecular weight hydrocarbon is a para substituted phenol functionalised with poly-ethoxylate units to create a surfactant of the general structure depicted by Structure A7 below, wherein R is a hydrocarbon with between about 2 and about 20 carbon atoms and m is between 2 and about 70. Commercial examples include the Dow Tergitol NP series, for which in Structure A7 the feature R is a hydrocarbon with 9 carbon atoms and m is between 4 and about 70, for example Tergitol NP -10, for which m=10. A further commercial example is the Dow Triton X series for which in Structure A7 the feature R is a highly branched hydrocarbon with 8 carbon atoms, for example T riton X-15 for which m is about 2 and Triton X-705 for which m is about 70:

[0146] Structure A7

[0147]

[0148] Other non-ionic hydrocarbon surfactants useful as any said second additional surfactant(s) include the BASF Tetronic series, comprised of tetrafunctional block copolymers of hydrophobic poly-propylene oxide (PPO) and hydrophilic poly-ethylene oxide (PEO) around a central ethylene diamine core with the general structure depicted by Structure A8, wherein W, X, Y and Z may be all PEO, all PPO or a mixture of both PEO and PPO. An example is Tetronic 1107 with a Mw around 15,000 g / mol and a higher proportion of PEO compared with PPO, understood to promote water solubility:

[0149] x

[0150]

[0151] YStructure A8

[0152] Another class of surfactants are the so-called gemini surfactants or dimeric surfactants, an example of which being the Surfynol series of acetylenic polyethylene oxides, a generalised structure of which is depicted by Structure A9, wherein n1 + n2 is in the range of from 2 to 80 such as the Surfynol 400 series produced by Evonik. Surfynol surfactants are based on a tetramethyldecyndiol backbone (a C14 alkyne) and have two poly-ethoxylated head groups. Examples include Surfynol 420 (for which n1 +n2=1.3 in Structure A9), Surfynol 440 (for which n1+n2=3.5 in Structure A9), Surfynol 465 (for which n1+n2=10 in Structure A9), and Surfynol 485 (for which n1+n2=30 in Structure A9):

[0153]

[0154] In further embodiments the surfactant may be derived from sorbitan reacted with a low molecular weight hydrocarbon which is an alkane or alkene with a carboxylic acid group, for example fatty acids derived from natural fats and oils, a generalised structure of which is depicted by Structure A10, wherein x is between 1 and 3, y is between 1 and 3 and R is a hydrocarbon carboxylic acid moiety which may be a straight chain, cyclic, aromatic and / or branched hydrocarbon moiety, further optionally containing saturated, monounsaturated, poly-unsaturated or aromatic hydrocarbon moieties having carbon chain lengths from 10 to 24. The carboxylic acid reacts by esterification with the sorbitan head group to form the surfactant. Well-known commercial examples of such surfactants include the Span surfactants manufactured by Croda. Examples for which x=y=1 include Span 20, wherein R is lauric acid, Span 40 wherein R is palmitic acid, Span 60 wherein R is stearic acid, and Span 80 wherein R is oleic acid. Various sesquioleates are also available with other ratios of sorbitan to carboxylate, for example Span 83 wherein x=2 and y=3, and R is oleic acid, and Span 85 wherein x=1 and y=3, and R is oleic acid.

[0155]

[0156] x / xStructure A10 A further commercial example is provided by the Tween surfactants, also manufactured by Croda with the general structure depicted by Structure A11, wherein w+x+y+z is typically in the range 10 to 100 and R is a carboxylate moiety, e.g. comprising a hydrocarbon portion. An example is Tween 20 wherein w+x+y+z = 20 and R is laurate, or Tween 80 wherein w+x+y+z = 80 and R is oleate.

[0157]

[0158] Structure A11

[0159] In some embodiments where present, any said second additional surfactant(s) may be present in the dispersion (or composition), individually or collectively, in an amount of from about 0.01% to about 10%, preferably from about 0.05% to about 5%, more preferably from about 0.1% to about 2%, even more preferably from about 0.15% to about 1%, even more preferably still from about 0.2% to about 0.75%, and further preferably from about 0.25% to about 0.5%, each by weight on an active basis. Some other ranges for the amount of second additional surfactant that may be present in the dispersion (or composition) include from about 0.1% to about 3%, from about 0.2% to about 2.5%, from about 0.3% to about 2.5%, from about 0.4% to about 2%, from about 0.5% to about 1.5%, each by weight on an active basis.

[0160] Separation CompositionCompositions useful for separating acidic gases and, in the case of carbon dioxide, for undertaking carbon capture and release, as contemplated herein, are a dispersion of an organic base in a base oil with a surfactant. The organic base, base oil and surfactant represent the three major constituents of the compositions in accordance with the present invention.

[0161] Without wishing to be bound by theory, it is believed that the surfactant facilitates and stabilizes the formation of an internal phase, for example micelles, in a continuous phase. The organic base may form the internal phase (or discontinuous phase), the base oil may form the external phase (or continuous phase), or the base oil may form the internal phase (or discontinuous phase) and the organic base may form the external phase (or continuous phase). In either case, the surfactant may form a boundary layer (or interfacial phase) between the internal and external phases. Accordingly, the organic base may, with the surfactant in a boundary layer, form micelles in the base oil. Despite the surfactant therefore forming, in effect, a barrier between the gaseous mixture and the organic base, significant carbon capture is still observed, and a broader range of organic bases may therefore be used in combination with a medium in which they exhibit no or low solubility.

[0162] As the organic base provides the functionality of separating the acidic gases and, in the case of carbon dioxide undertaking the carbon capture, it is desirable that significant quantities of the organic amine are present in the composition. Accordingly, in some preferred embodiments, the organic base is present in an amount of at least 5%, preferably at least 10%, more preferably at least 20%, even more preferably at least 30% and even more preferably still at least 40% by weight of the composition. Accordingly, some preferred ranges of the amount of organic base present in the composition include from 5% to 80%, from 10% to 70%, from 20% to 60%, from 30% to 55% and from 40% to 50% by weight of the composition on an active basis.

[0163] The basicity of the composition may also be described by means of the composition’s Total Base Number (TBN), which as used herein may be measured in accordance with ASTM D4739. Accordingly, the TBN of the composition may be preferably in a range of from about 50 mg KOH / g to about 900 mg KOH / g, such as from about 75 mg KOH / g to about 800 mg KOH / g, preferably from about 100 mg KOH / g to about 700 mg KOH / g, such as from about 200 mg KOH / g to about 650 mg KOH / g or from about 250 mg KOH / g to about 500 mg KOH / g, as measured in accordance with ASTM D4739 (on an oil free active ingredient basis).

[0164] In some embodiments, the organic base forms, or is comprised within, an internal (or alternatively described, dispersed) phase in the base oil. The phase comprising the organic base may further comprise water but may not further comprise water, i.e. the organic base may be dry, or substantially dry. Any water may be present in the composition before being exposed to the gaseous mixture, or may be derived from the gaseous mixture, such as where the gaseous mixtures is an exhaust gas (also known as a flue gas) from a fossil fuel combustion process and the composition absorbs water from the gaseous mixture.

[0165] It is desirable that the organic base (e.g. organic amine) is labile, or is not immobilised. The organic base may be described as labile if the organic base is cross-linked to a degree less than about 0.5%, preferably less than about 0.2%, more preferably less than about 0.1%, even more preferably less than about 0.01% and even more preferably still exhibits no, or substantially no, cross-linking; if the organic basehas not been exposed to a cross-linking agent sufficient to result in substantial, preferably any, crosslinking; if the organic base is liquid (or in a solvated phase, such as an aqueous phase) at the operating conditions of the carbon capture process; and / or if the organic base has an number average molecular weight, Mn, not more than about 1000 g / mol, such as no more than about 360 g / mol, preferably from about 30 g / mol to about 250 g / mol, more preferably from about 40 g / mol to about 150 g / mol, even more preferably from about 50 g / mol to about 100 g / mol and even more preferably still from about 60 g / mol to about 90 g / mol. Accordingly, the ranges of cross-linking specified above provide the maximum proportion of basic functionality, or maximum proportion of organic base molecules forming covalent bonds to other organic base molecules, with the remaining basic functionality of the organic base typically undergoing only hydrogen bonding or Van der Waals interactions to other molecules.

[0166] Without wishing to be bound by theory, it is believed that providing labile organic bases improves the motility (or mobility) of the organic base in the dispersion, improving acidic gas uptake by improving the availability of the organic base. As cross-linking the organic base typically proceeds via the basic functionality, less such functionality is then available for carbon capture. By way of example, especially in the case when the organic base is an organic amine, the amine functionality (e.g. primary amine functionality or secondary amine functionality) is reacted in forming cross-linking, reducing the amine functionality for carbon capture.

[0167] The surfactant, meanwhile, will typically form a minor component of the composition. The amount of surfactant desired will depend on the amount of organic amine that is to be dispersed in the base oil, as too little surfactant may reduce the stability of the dispersion while too much becomes free surfactant that offers little practical benefit, and may even destabilise the dispersion, while also potentially introducing other problems, such as raising the overall specific heat capacity of the composition. Some preferred ranges for the amount of ionic surfactant present in the composition, when present as the only surfactant, include from about 0.1% to about 10%, from about 0.25% to about 5%, from about 0.3% to about 4.5%, from about 0.4% to about 4%, from about 0.5% to about 3%, from about 0.7% to about 2% and from about 1 % to about 1.5%, such as about 1.25%, each on an active basis, by weight of the composition and / or dispersion. Some preferred ranges for the total amount of surfactant present in the composition include from about 0.1 % to about 20%, from about 0.2% to about 15%, from about 0.3% to about 10%, from about 1 % to about 8%, from about 1.5% to about 7%, from about 2% to about 6% and from about 3% to about 5%, such as about 4%, each on an active basis, by weight of the composition and / or dispersion.

[0168] Where the composition comprises an additional surfactant as described above, some preferred ranges for the amount of additional surfactant present in the composition include from about 0.1% to about 10%, from about 0.2% to about 9.5%, from about 0.5% to about 9%, from about 1 % to about 8%, from about 1.5% to about 7%, from about 1.7% to about 6% or from about 2% to about 4.5%, such as about 2.2% to about 4%, or about 2.5% to about 3%, each on an active basis, by weight of the composition and / or dispersion.

[0169] Having particular regard to the amount of organic amine and the surfactant quantities described above, the remainder of the composition will typically consist of the base oil and other impurities or additives, in particular other impurities or additives dissolved in the base oil and therefore also forming part of thecontinuous phase where the base oil makes up the continuous phase. In some embodiments, to form an effective continuous phase, the base oil (which may include impurities and additives dissolved therein) may be present in a significant or majority amount, such as about 50% by volume of the composition. Some preferred ranges for the amount of base oil (or continuous phase) present in the composition include from about 10% to about 90%, preferably from about 20% to about 80%, more preferably from about 30% to about 70%, even more preferably from about 40% to about 60% and even more preferably still from about 45% to about 55%, in each case by mass of the composition.

[0170] As referred to above, the separation composition may further comprise one or more additives, that may be in the internal or external phase, at the interface, or combinations thereof. Examples of such additives include antioxidants, corrosion inhibitors, antifoaming agents, pH modifiers, buffers, metal chelators, seal swell agents, flow improvers, carbon capture promoters (including water) and viscosity modifiers.

[0171] Acidic Gas Separation Methods, Processes and Systems

[0172] The present invention contemplates methods, processes and systems for the separation of acidic gases from a gaseous mixture comprising them. In particular, the present invention provides methods, processes and systems for the separation (also referred to in the art as capture) of carbon dioxide from a gaseous mixture comprising carbon dioxide.

[0173] The methods and processes according to these aspects of the present invention are achieved generally by contacting the gaseous mixture comprising the acidic gas (particularly carbon dioxide) with a separation composition as described in detail above.

[0174] According to the methods of separating acidic gases (especially carbon dioxide) from a gaseous mixture containing such acidic gases (as the context requires, carbon dioxide), therefore, the method comprises contacting the gaseous mixture with a dispersion of at least one organic base and a base oil, the dispersion further comprising at least one surfactant. Alternatively, in general, the method may comprise contacting the gaseous mixture with a composition comprising a dispersion of at least one organic base and a base oil, the dispersion further comprising at least one surfactant, notably wherein the composition is the separation composition as described in detail above. Accordingly, the composition, dispersion and components thereof may further have any of the features described above alone or in combination. It is also to be understood that the method may equally be described as contacting the dispersion (or composition) with the gaseous mixture.

[0175] According to the processes of separating acidic gases (especially carbon dioxide) from a gaseous mixture containing such acidic gases (as the context requires, carbon dioxide), therefore, the processes comprise the steps of:

[0176] a. providing, charging or loading a vessel with a composition comprising a dispersion of at least one organic base and a base oil, the dispersion further comprising at least one surfactant; and

[0177] b. introducing the gaseous mixture to the vessel.

[0178] The steps of the processes may be carried out in any order, (i.e. the gaseous mixture may first be introduced into the vessel which is then provided, charged or loaded with the composition). This may be phrased as providing, charging or loading the gaseous mixture to the vessel and introducing the composition. Preferably, the steps are carried out in the order above. Further optional steps may follow thesteps above and include transferring the composition to a desorber and / or heating the composition to release (interchangeably desorb or remove) the acidic gas (especially carbon dioxide) from the composition. Also preferably, the composition may be introduced via a spraying or other droplet or narrow stream forming mechanism to improve the surface area of composition available to be accessed by the gaseous mixture in turn to improve acidic gas (especially carbon dioxide) separation. The composition, dispersion and components thereof may further have any of the features described above alone or in combination. The gaseous mixture may contact the dispersion at any temperature in which the dispersion is a liquid and / or fluid and the rate of carbon capture exceeds that of carbon release from the dispersion or from the organic base. In some preferred embodiments, the gaseous mixture contacts the dispersion at a temperature of from about 20 °C to about 100 °C such as any of about 20 °C, about 25 °C, about 30 °C, about 40 °C, about 50 °C or about 60 °C to any of about 100 °C, about 95 °C about 90 °C, about 80 °C, about 70 °C or about 60°C. As the dispersion may reasonably be expected to have a significantly higher specific heat capacity than the gaseous mixture, and be more massive, the expression may be alternatively described as the dispersion being at a temperature in the range. Typically, any step of releasing the acidic gas, such as carbon dioxide, from the dispersion would be undertaken by heating the dispersion to a temperature greater than that at which the gaseous mixture contacted the dispersion, for example to a temperature greater than about 60 °C, greater than about 70 °C, greater than about 80 °C, greater than about 100 °C or greater than about 120 °C. Exemplary temperature differences between carbon capture and carbon release steps include ranges with upper and lower bounds selected from about 20, 25, 30, 35, 40, 45, 50, 60, 70, 80 or 100 °C, such as from about 20 °C to about 100 °C, from about 20 °C to about 80 °C, from about 20 °C to about 70 °C and so on, from about 25 °C to about 100 °C, from about 25 °C to about 80 °C, from about 25 °C to about 70 °C and so on, and also so on for each combination of upper and lower limit from the list provided above. Exemplary such ranges include from about 20 °C to about 100 °C, from about 25 °C to about 80 °C, from about 30 °C to about 70 °C, from about 35 °C to about 60 °C, and from about 40 °C to about 50 °C. Alternative methods to release the acidic gas include a reduction of pressure in the system, i.e. around the dispersion, to drive off the acidic gas (pressure swing), or the use of a purge gas, such as steam in the case of steam stripping, or purging with another gas, such as nitrogen or air, preferably while heating the dispersion to an elevated temperature to release the acidic gas.

[0179] The gaseous mixture may contact the dispersion while having any concentration of acidic gas (especially carbon dioxide), for example the acidic gas (especially carbon dioxide) concentration in the gaseous mixture (by weight or volume percent) may be at least, or greater than, about 2%, greater than about 5%, greater than about 10%, greater than about 15%, greater than about 20%, greater than about 30%, greater than about 40%, greater than about 60%, greater than about 80%, or greater than about 99.9%, such as any ranges from about 2%, about 3%, about 5%, about 10%, about 15% or about 20% to about 25%, about 30%, about 40%, about 60%, about 80%, about 90%, about 95%, about 99%, about 99.9% or about 100% to about 100%, including without limitation ranges such as from about 5% to 99.9%, from about 10% to about 80%, from about 15% to about 40% or from about 20% to about 30%.

[0180] A schematic representation of an apparatus / system suitable for the processes and methods describedabove is shown in Fig. 1. An example process involves cooling a gaseous mixture (1) (containing acidic gases such as carbon dioxide) in a cooling tower (not shown), before contacting the gaseous mixture under optimum absorption conditions in an absorption tower (2), via such methods as described above, the absorption tower containing a composition comprising a dispersion of at least one organic base and a base oil, the dispersion further comprising at least one surfactant. This process reduces the concentration of acidic gas in the gaseous mixture (3), producing a rich solvent (4), in this sense meaning acidic gas rich, carbon rich or carbon dioxide rich. This could be a continuous process, whereby the rich solvent is transferred or pumped (5) to a desorber (7), optionally via a heat exchanger (6), where the rich solvent is heated to an optimum temperature using an appropriate method to release the captured acidic gas (8) and regenerate the lean solvent (9), in this sense meaning acidic gas lean, carbon lean, or carbon dioxide lean. The lean solvent is then transferred or pumped (10) back to the absorber (2), optionally via a heat exchanger (6), coming back into contact with the gaseous mixture and enabling the process to operate in a continuous fashion.

[0181] Also contemplated by the present invention are systems for separating acidic gases from a gaseous mixture comprising such acidic gases such as described above as used in the processes and methods of the present invention, the systems comprising a vessel (a reactor) with means for fluid introduction and removal, wherein “fluid” includes a gas or a liquid, and the vessel may comprise means to introduce to the vessel and / or remove from the vessel one or more fluids such as gases or liquids, including the gaseous mixture comprising an acidic gas (especially a gaseous mixture comprising carbon dioxide) and a separation composition as hereinbefore described. The vessel may also be a reactor, such as a stirred tank reactor or a bubble tank reactor or falling film reactor, an absorption tower or column, such as a plate or tray column, or a packed column (using random or structured packing), a spray tower, a membrane contactor, or using any other process known to those skilled in the art. In order to affect the acidic gas separation, the vessel contains a composition comprising a dispersion of at least one organic base and a base oil, the dispersion further comprising at least one surfactant, at least at the point of use for acidic gas separation. The composition, dispersion and components thereof may further have any of the features of the compositions, dispersions and components thereof described above, alone or in combination.

[0182] Accordingly, the compositions and dispersions described herein may be used to separate acidic gases (for example, carbon dioxide) from a gaseous mixture containing such acidic gases, and to capture carbon dioxide from a gaseous mixture containing carbon dioxide.

[0183] As demonstrated in the examples included below, the methods, processes, compositions and uses of the present invention may achieve a gram for gram (alternatively referred to as gram per gram, acidic gas or carbon dioxide loading measured in grams of carbon dioxide (or acidic gas) per gram of solvent, i.e. dispersion or composition, (gco2 / gSoivent), of from about 0.001 gco2 / gSoivent to about 1 gco2 / gSoivent, from about 0.01 gco2 / gSoivent to about 0.5 gco2 / gSoivent or from about 0.04 gco2 / gSoivent to about 0.25 gco2 / gSoivent, such as from about 0.04 gco2 / gSoivent to about 0.2 gco2 / gSoivent (or from about 0.04 gco2 / gSoivent to about 0.17 gco2 / gSoivent), from about 0.07 gco2 / gSoivent to about 0.15 gco2 / gSoivent or from about 0.08 gco2 / gSoivent to about 0.12 gco2 / gSoivent, in each case where gco2 / gSoivent may be replaced with gacidicgas / gSoivent.

[0184] The dimensions and values disclosed herein are not to be understood as being strictly limited to theexact numerical values recited. Rather, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as "40 mm" is intended to mean "about 40 mm."

[0185] Every document cited herein, including any cross referenced or related patent or application, is hereby incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention.

[0186] Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.

[0187] While certain particular embodiments of the present invention have been illustrated and described herein, it would be apparent to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention, and it is intended, accordingly, to cover in the accompanying claims all such changes and modifications that are within the scope and spirit of this invention.

[0188] Unless otherwise stated or evidently required to be performed under different conditions, measurements described herein are made under standard conditions. Molecular weight (Mn, g / mol) is or may be determined by gel permeation chromatography using polystyrene standards, unless otherwise indicated. Examples

[0189] The invention is further detailed below with reference to the following non-limiting examples:

[0190] Example 1 - Preparation of Surfactants

[0191] Example 1.1 - Calcium Alkyl-Sulfonate (Ca Sulf)

[0192] 500 g of Infineum supplied commercial grade alkyl sulfonic acid with an average alkyl chain molecular weight Mn of about 540 g / mol was weighed into a 3-litre flask followed by 1009 g of xylene. The flask was placed on a rotary evaporator with the oil bath set to 50°C and spun until the alkyl sulfonic acid had dissolved. 50 g of calcium hydroxide (supplied by L’Hoist) and 48.3 g of methanol was added and the flask spun for a further 1 hour at 50°C. The contents were then placed in a Sigma 8k process centrifuge and spun at 2,500 rpm for 1 hour. After, the supernatant liquid was decanted and the solvents removed in vacuo while heating to 125 °C. During the distillation, 410 g of XOMAPE150 oil was added to increase fluidity of the resulting viscous product with an approximate active ingredient proportion of 50 wt.%.

[0193] Example 1.2 - Magnesium Alkyl-Salicylate (Mg Sal)

[0194] 400g of Infineum supplied commercial grade alkyl salicylic acid with an average alkyl chain molecular weight Mn of about 250 g / mol and 703 g of xylene were weighed into a 2 litre flask, fitted with a Rushton type turbine overhead stirrer, a thermocouple, and a nitrogen line, in an electromantle heater controlled by a WEST 4400 controller, and Dean and Stark apparatus was added. Methanolic solutions of 55.7 g magnesium chloride (supplied by Sigma Aldrich, CAS: 7786-30-3) and 38.6 g sodium hydroxide (supplied by Sigma Aldrich, CAS: 1310-73-2) were prepared using methanol (supplied by Sigma Aldrich, CAS: 67-56-1). The methanolic solutions of sodium hydroxide and magnesium choride were transferred into additionPF2025M002 / WC

[0195] funnels which were placed into ports on the reactor.

[0196] The methanolic magnesium chloride and sodium hydroxide solutions were added slowly at a similar rate over approximately 25 minutes while stirring under an inert nitrogen gas flow. The reaction was distilled to remove methanol, and then the Dean and Stark method was carried out once the temperature reached 90 °C and the temperature then ramped to remove water. The resulting mixture was placed in a Sigma 8k process centrifuge and spun at 2,500 rpm for 1 hour. After, the supernatant liquid was decanted and the solvents removed in vacuo while heating to 125 °C. During the distillation, 400 g of XOMAPE150 oil was added to increase fluidity of the resulting viscous product with an approximate active ingredient proportion of 50 wt.%.

[0197]

[0198] 1.3 - Sodium Alkyl-Sulfonate

[0199] Sodium Alkyl-Sulfonate was synthesised via the procedure used for Magnesium Alkyl-Salicylate described in Example 1.2, however 500g of Infineum supplied commercial grade alkyl sulfonic acid with an average alkyl chain molecular weight of 540 g / mol was used instead of alkyl salicylic acid, and 25.5 g sodium hydroxide (supplied by Sigma Aldrich, 98% a.i., CAS: 1310-73-2) was used instead of calcium chloride. The resulting product had an approximate active ingredient proportion of 50 wt.%.

[0200] Example 1.4 - Potassium Alkyl-Salicylate (K Sal)

[0201] Potassium Alkyl-Salicylate was synthesised via the procedure used for Magnesium Alkyl-Salicylate described in Example 1.2, however 72.5 g potassium hydroxide (supplied by Sigma Aldrich, 85% active ingredient, CAS: 1310-58-3) was used instead of sodium hydroxide. The resulting product had an approximate active ingredient proportion of 50 wt.%.

[0202]

[0203] 1.5- 220 g of polyisobutenyl succinic anhydride (PIBSA), with molecular weight of approximately 1000 Mn and saponification number of 102 mgKOH / g, was charged to a 0.5L baffled reactor, followed by 46 g of a low viscosity base oil. The reaction mixture was subsequently heated to 90 °C with stirring before the addition of 26 g of diethylethanolamine, purchased from Thermo Scientific (CAS: 102-71-6). The temperature of the reaction was then increased to 120 °C and maintained for 3.5 hours before removing the heat. Allowed to cool overnight, the mixture was transferred to a rotary evaporator in a pear-shaped flask and heated to 90 °C for 4 hours at 30-40 mBar before removing from heat and decanting the product. The resulting product had an approximate active ingredient proportion of 79 wt.%.

[0204] Table E-1 summarises the ionic surfactants described in Examples 1.1 to 1.4.

[0205] TABLE E-1. Metal-containing Ionic Surfactants for Preparing Acidic Gas Separation Compositions Example Metal Anion

[0206] Calcium Alkyl-Sulfonate Magnesium Alkyl-Salicylate

[0207] Sodium Alkyl-Sulfonate Potassium Alkyl-Salicylate

[0208] Example 2 - Preparation of Acidic Gas Separation CompositionsA pre-blend of oil-soluble components was prepared by adding the appropriate surfactant from Example 1 to an appropriate base oil (e.g. Spectrasyn2) in a 1.5 litre glass beaker, weighed out using a Sartorius Combics 1 balance. If applicable, a second oil-soluble surfactant was added at this stage to achieve approximately 600 g of the oil phase pre-blend materials in the correct ratios. The mixture was stirred using an overhead stirrer (IKA EUROSTAR 40) at 200RPM, heated to 60 °C using a hotplate (CAT M26 G2), and held at that temperature with stirring for 30 mins.

[0209] The mixture was then cooled and transferred to a mixer (Silverson L5M-A) fitted with a Silverson emulsor screen workhead. In a separate beaker, a pre-blend of water-soluble components was prepared by adding the organic base to a quantity of water (if required) in a 1.5 litre glass beaker, the quantity of water being appropriate to achieve the desired final formulation composition, weighed out using a Sartorius Combics 1 balance. If applicable, a second water-soluble surfactant was added at this stage to achieve approximately 600g of the aqueous-phase pre-blend to achieve the desired water and surfactant ratio in the final product. The aqueous phase pre-blend was then added to the oil-phase pre-blend and the resulting mixture was heated to 70 °C unless otherwise stated using a hotplate (CAT M26 G2) while stirring at the maximum stirring speed achievable before splashing was observed outside the confines of the 1.5 litre glass beaker (stirred at 4000 RPM) and held at that temperature with stirring for 6 hours, before being decanted immediately and allowed to cool to room temperature.

[0210] This experimental method was used with a range of quantities and identities of chemical components added as detailed in Table E-2. The surfactant treat rates as detailed in Table E-2 are reported on an active ingredient basis. Amines used in these examples are monoethanolamine (MEA, CAS: 141-43-5, 99% purity), alternatively 2-amino-2-methyl-1 -propanol (AMP, CAS: 124-68-5, 95% purity, 5% water impurity), 1-(2-hydroxyethyl)piperazine (Ethanol-PZ, CAS: 103-76-4, 98% purity), 1-(2-aminoethyl)piperazine (aminoethyl-PZ, CAS: 140-31-8, 99% purity) and piperazine (PZ, CAS: 110-85-0, 99% purity). The viscosities of the resultant acidic gas separation compositions are provided in Table E-3.

[0211] TABLE E-2. Acidic Gas Separation Compositions

[0212] Example Amine / wt.% Surfactant / wt.% Base oil Example 2.1 MEA / 30 Example 1.1 / 0.25 Spectrasyn 2 Example 2.2 MEA / 30 Example 1.1 / 0.63 Spectrasyn 2 Example 2.3 MEA / 30 Example 1.1 / 1 Spectrasyn 2 Example 2.4 MEA / 30 Example 1.1 / 1.25 Spectrasyn 2 Example 2.5 MEA / 30 Example 1.1 / 1.5 Spectrasyn 2 Example 2.6 MEA / 30 Example 1.1 / 2.5 Spectrasyn 2 Example 2.7 MEA / 30 Example 1.1 / 5 Spectrasyn 2 Example 2.8 MEA / 30 Example 1.1 / 0.25 Spectrasyn 2

[0213] Water / 10

[0214] Example 2.9 MEA / 30 Example 1.1 / 0.63 Spectrasyn 2

[0215] Water / 10

[0216] Example 2.10 MEA / 30 Example 1.1 / 1 Spectrasyn 2PF2025M002 / WC

[0217] Water / 10

[0218] Example 2.11 MEA / 30 Example 1.1 / 1.25 Spectrasyn 2 Water / 10

[0219] Example 2.12 MEA / 30 Example 1.1 / 1.5 Spectrasyn 2 Water / 10

[0220] Example 2.13 MEA / 30 Example 1.1 / 2.5 Spectrasyn 2 Water / 10

[0221] Example 2.14 MEA / 30 Example 1.1 / 5 Spectrasyn 2 Water / 10

[0222] Example 2.15 MEA / 10 Example 1.1 / 1.25 Spectrasyn 2 Example 2.16 MEA / 20 Example 1.1 / 1.25 Spectrasyn 2 Example 2.17 MEA / 40 Example 1.1 / 1.25 Spectrasyn 2 Example 2.18 MEA / 50 Example 1.1 / 1.25 Spectrasyn 2 Example 2.19 MEA / 60 Example 1.1 / 1.25 Spectrasyn 2 Example 2.20 MEA / 30 Example 1.1 / 1.25 XOMAPE100 Example 2.21 MEA / 30 Example 1.1 / 1.25 EHC45 Example 2.22 MEA / 30 Example 1.1 / 1.25 YUBASE2 Example 2.23 MEA / 30 Example 1.1 / 1.25 Spectrasyn 4 Example 2.24DMEA / 30 Example 1.1 / 1.25 Isopar M Example 2.25 MEA / 30 Example 1.1 / 1.25 Neoflo 1-58 Example 2.26 MEA / 30 Example 1.1 / 1.25 Neoflo 1-68 Example 2.27 MEA / 15 Example 1.1 / 1.25 Spectrasyn 2 Ethanol-PZ / 15

[0223] Example 2.28 MEA / 15 Example 1.1 / 1.25 Spectrasyn 2 Aminoethyl-PZ / 15

[0224] Example 2.29* MEA / 15 Example 1.1 / 1.25 Spectrasyn 2 AMP / 15

[0225] Example 2.30* AMP / 13.5 Example 1.1 / 1.25 Spectrasyn 2 PZ / 6.5

[0226] Water / 30

[0227] Example 2.31 MEA / 30 Example 1.2 / 1.25 Spectrasyn 2 Example 2.32 MEA / 30 Example 1.3 / 1.25 Spectrasyn 2 Example 2.33 MEA / 30 Example 1.4 / 1.25 Spectrasyn 2 Example 2.34 MEA / 30 Example 1.1 / 1.88 Spectrasyn 2 *heated to 50°C in lieu of 70°C (after addition of organic base) owing to flash point of AMP.

[0228] “heated to 60°C in lieu of 70°C (after addition of organic base) owing to flash point of Isopar M.

[0229] TABLE E-3.

[0230] Kinematic Viscosity of Acidic Gas Separation Compositions, measured at 40 °C using ASTM D445-24Example Kinematic Viscosity / cSt Example Kinematic Viscosity / cSt Example 2.1 14.4 Example 2.18 26.9 Example 2.2 10.4 Example 2.19 44.5 Example 2.3 10.5 Example 2.20 46.2 Example 2.4 10.3 Example 2.21 52 Example 2.5 17.8 Example 2.22 19.6 Example 2.6 11.2 Example 2.23 40.2 Example 2.7 9.2 Example 2.24 3.7 Example 2.8 19.3 Example 2.25 6.2 Example 2.9 13.4 Example 2.26 5.8 Example 2.10 13.7 Example 2.27 13.9 Example 2.11 13.8 Example 2.28 10.5 Example 2.12 12.9 Example 2.29 14.73 Example 2.13 18.9 Example 2.30 96.35 Example 2.14 31.7 Example 2.31 6.1 Example 2.15 6.1 Example 2.32 10.6 Example 2.16 7.3 Example 2.33 5.2 Example 2.17 16.8 Example 2.34 15.7 Example 3 - Carbon Dioxide Absorption Experiment

[0231] Acidic gas separation compositions according to Example 2 were charged into a 250mL Radleys Ready jacketed glass reactor, fitted with an oil bath circulator to control the temperature (Huber Petite Fleur), a thermocouple, a gas sparge and an overhead stirrer (Heidolph Hei-TORQUE Ultimate 400). Gas flow enters the reactor via flexible vinyl tubing connected to a stainless steel sparge (pore size 160 urn) inserted through the reactor headpiece, and submerged below the surface of the acidic gas separation composition, where it contacts the acidic gas separation composition and the gas then exits the reactor through two condensers (the second condenser fitted with a catch pot) cooled to 0 °C using a chiller (Unichiller 022 OLE), subsequently passing through an inline particulate filter (10 micron) and a mass flow meter (Bronkhorst EL-Flow Select) before flowing through to the IR detector (Signal S4 Pulsar GFC IR Analyser). Calibrated mass flow controllers (Bronkhorst EL-Flow Select), used to control the acidic gas composition, and other accessories (such as the oil bath and overhead stirrer) were controlled via a serial box (StarTech 16 Port USB to Serial RS232 Adapter) and PC (Syrris Atlas PC Software 1). The mass flow controllers were used to control the flow of gas entering the reactor, and to measure the gas exiting the reactor, to ensure no leakage occurred during an experiment, and were run alongside the IR detector and its associated software (S4i) to enable CO2 uptake amounts to be calculated.

[0232] In this absorption experiment, the following conditions were used unless stated otherwise. A measured amount of acidic gas separation composition (~145g) was charged into the reactor under a flow of 640 ml min-1N2, and the mass was measured using a Sartorius MCA524S-2S00-I balance (± 0.05mg). The reactor was then assembled with the thermocouple, condenser, sparge and overhead stirrer. The temperature of the reactor was set to 40 °C and the overhead stirrer to 500RPM. After the desired absorption temperature wasreached (ca. 5 mins), the CO2 uptake measurement was started by introducing CO2 into the gas feed at 20 vol.% concentration with a N2 diluent gas, providing a total flow rate of 800 ml min-1. The absorption experiment was then stopped after saturation of the solvent by CO2 was observed. This was typically after approximately 140 mins, but is dependent on the amount of organic base present in the acidic gas separation composition. To calculate the gco2 / gSoivent loading value, the number of grams of CO2 absorbed by the acidic gas separation composition was divided by the number of grams of solvent charged to the reactor. This also allows for the number of moles of CO2 per number of moles of amine (nCO2 / namine) to be calculated. This experimental procedure is referred to herein as the “IR detector” procedure.

[0233] Accordingly, the overall error between replicate measurements carried out on the same sample using the IR detector method was 2.5%.

[0234] A first set of absorption experiments using the IR procedure above was undertaken, varying the concentration of calcium alkyl-sulfonate surfactant (of Example 1.1) while maintaining the concentration and identity of organic base (monoethanolamine). The results appear in Table E-4 showing significant CO2 loading achieved by the separation composition across a range of surfactant levels. These results compare favourably with an aqueous solution of 30 wt.% monoethanolamine, which may typically achieve CO2 loadings of 0.129 gco2 / gSoivent and 0.597 nco2lnamme, notably in the context of the energetic savings offered by the considerably lower specific heat capacity of the composition.

[0235] In a second set of absorption experiments using the same IR procedure, the effect of the presence of a small amount of water (10 wt.%) was studied, again varying the concentration of calcium alkyl-sulfonate surfactant (of Example 1.1) while maintaining the concentration and identity of organic base (monoethanolamine). The results appear in Table E-5, and when compared with Table E-4, show a preference for increased CO2 loadings when water is present in the separation composition, across a range of surfactant levels.

[0236] A third set of absorption experiments using the IR procedure above was further undertaken, varying the concentration of monoethanolamine organic base while maintaining the concentration and identity of calcium alkyl-sulfonate surfactant (of Example 1.1) in the composition of Example 2. The results of this third set of experiments appear in Table E-6, Figure 2 and Figure 3 showing significant CO2 loading achieved by the separation composition across a range of organic base levels in a broadly linear relationship.

[0237] A fourth set of experiments using the IR procedure above was further undertaken, varying the identity of the base oil while maintaining the concentration and identity of the monoethanolamine organic base and while maintaining the concentration and identity of the calcium alkyl-sulfonate surfactant (of Example 1.1) in the composition of Example 2. The results of this fourth set of experiments appear in Table E-7 indicating that different base oils can be used to produce dispersions capable of achieving similar CO2 loadings. A fifth set of experiments using the IR procedure above was further undertaken, varying the identity and concentration of the organic base while maintaining the concentration and identity of the calcium alkyl-sulfonate surfactant (of Example 1.1) in the composition of Example 2. The results of this fifth set of experiments appear in Table 8 showing that dispersions including MEA and different organic bases can be utilised in the present invention to capture acidic gases such as CO2. Furthermore, Table E-8 demonstrates that complex mixtures of two or more components are capable of forming a dispersion to capture CO2, inthis specific case, MEA with ethanol-PZ, aminoethyl-PZ, or AMP, or separately the combination of AMP, PZ and water. Example 2.30 includes a mixture of components AMP, PZ and water that does not include MEA but is still capable of forming a dispersion to capture CO2.

[0238] A sixth set of experiments using the IR procedure above was further undertaken, varying the identity of the surfactant (of Example 1.1, 1.2, 1.3, 1.4) while maintaining the concentration and identity of the organic base in the composition of Example 2. The results of this sixth set of experiments appear in Table E-9 showing that surfactants with different metal cores and soaps can be used to produce dispersions capable of achieving similar CO2 loadings.

[0239] A seventh set of experiments using the IR procedure above was further undertaken, demonstrating the addition of a further surfactant (Example 1.5) while maintaining the identity of the calcium alkyl-sulfonate surfactant (of Example 1.1). The results of this seventh set of experiments appear in Table E-10 showing that a combination of ionic and non-ionic surfactants can be used to produce dispersions capable of achieving similar CO2 loadings.

[0240] TABLE E-4: Carbon dioxide separation results with varying concentration of calcium alkyl-sulfonate surfactant (Example 1.1) and fixed concentration of monoethanolamine organic base (30 wt.%)

[0241] Ca Sulf CO2 Loading

[0242] Example

[0243] (wt.%) QcO2 / Qsolvent flCO / namine

[0244] Example 2.1 0.25 0.098 0.45

[0245] Example 2.2 0.63 0.101 0.47

[0246] Example 2.3 1.00 0.099 0.46

[0247] Example 2.4 1.25 0.094 0.44

[0248] Example 2.5 1.50 0.099 0.46

[0249] Example 2.6 2.50 0.096 0.45

[0250] Example 2.7 5.00 0.117 0.54

[0251] TABLE E-5.

[0252] Carbon dioxide separation results with varying concentration of calcium alkyl-sulfonate surfactant (Example 1.1) and fixed concentration of monoethanolamine organic base (30 wt.%) and water (10 wt.%)

[0253] Ca Sulf CO2 Loading

[0254] Example

[0255] (wt.%) QcO2 / Qsolvent RCO2 / Ramine

[0256] Example 2.8 0.25 0.103 0.48

[0257] Example 2.9 0.63 0.104 0.48

[0258] Example 2.10 1.00 0.100 0.46

[0259] Example 2.11 1.25 0.108 0.5

[0260] Example 2.12 1.50 0.097 0.45

[0261] Example 2.13 2.50 0.112 0.52

[0262] Example 2.14 5.00 0.118 0.55TABLE E-6. Increasing concentrations (wt.%) of monoethanolamine with fixed calcium alkyl-sulfonate (Example 1.1) concentration (1.25 wt.%)

[0263] Monoethanolamine CO2 Loading Example

[0264] (wt.%) QcO2 / Qsolvent flCO / namine Example 2.15 10 0.026 0.36 Example 2.16 20 0.069 0.48 Example 2.4 30 0.094 0.44 Example 2.17 40 0.126 0.44 Example 2.18 50 0.159 0.44 Example 2.19 60 0.200 0.46

[0265] TABLE E-7. Fixed concentration of monoethanolamine (30 wt.%) and calcium alkyl-sulfonate surfactant (Example 1.1) (1.25 wt.%) with different base stocks CO2 Loading Example Base Oil

[0266] gCO2 / gsolventnCO2 / namineExample 2.4 Spectrasyn 2 0.094 0.44 Example 2.20 XOMAPE100 0.098 0.45 Example 2.21 EHC45 0.093 0.43 Example 2.22 YUBASE2 0.098 0.45 Example 2.23 Spectrasyn 4 0.100 0.46 Example 2.24 Isopar M 0.105 0.49 Example 2.25 Neoflo 1-58 0.100 0.46 Example 2.26 Neoflo 1-68 0.098 0.46

[0267] TABLE E-8: Fixed concentration of calcium alkyl-sulfonate surfactant (Example 1.1) (1.25 wt.%) with different organic bases Example Organic CO2 Loading

[0268] wt.%

[0269]

[0270] BaSO QcO2 / Qsolvent RCO2 / Ramine Example 2.4 MEA 30 0.094 0.44 Example 2.27 MEA 15 0.078 0.49

[0271] Ethanol-PZ 15

[0272] Example 2.28 MEA 15 0.105 0.66

[0273] Aminoethyl-PZ 15

[0274] Example 2.29 MEA 15 0.089 0.49

[0275] AMP 15

[0276] Example 2.30 AMP 13.5 0.062 0.41

[0277] PZ 6.5

[0278] Water 30TABLE E-9. Fixed concentration of monoethanolamine (30 wt.%)

[0279] with different surfactants at matched active ingredient concentration

[0280] CO₂ Loading Example Surfactant wt.%

[0281] gCO2 / gsolventnCO2 / namineExample 2.4 Example 1.1 1.25 0.094 0.44 Example 2.31 Example 1.2 1.25 0.065 0.30 Example 2.32 Example 1.3 1.25 0.097 0.45 Example 2.33 Example 1.4 1.25 0.063 0.29

[0282] TABLE E-10. Fixed concentration of monoethanolamine (30 wt.%) with combination of surfactants CO2 Loading Example Surfactant wt.%

[0283] gCO2 / gsolventnCO2 / namineExample 2.4 Example 1.1 1.25 0.094 0.44

[0284] Example 1.1 1.88

[0285] Example 2.34 _ 0.088 0.41

[0286] Example 1.5 5.33

Claims

Claims1. A method of separating acidic gases from a gaseous mixture containing such acidic gases, the method comprising contacting the gaseous mixture with a dispersion of at least one organic base and an oleaginous medium, the dispersion further comprising an ionic surfactant.

2. A process for separating acidic gases from a gaseous mixture comprising such acidic gases, comprising the steps of:a. providing, charging or loading a vessel with a composition comprising a dispersion of at least one organic base and an oleaginous medium, the dispersion further comprising an ionic surfactant; and b. introducing the gaseous mixture to the vessel.

3. A method according to Claim 1 or a process according to Claim 2, wherein the ionic surfactant is a metal-containing ionic surfactant.

4. A method or process according to any preceding claim, wherein the at least one organic base contains amine functionality, preferably selected from primary amine functionality, secondary amine functionality, tertiary amine functionality, or combinations thereof and more preferably selected from primary amine functionality, secondary amine functionality or both primary and secondary amine functionality.

5. A method or process according to Claim 4 wherein the at least one organic base further comprises a hydroxy group.

6. A method or process according to any preceding claim wherein at least one organic base is selected from Piperazine, N-Methyldiethanolamine, Monoethanolamine, 2-Amino-2-methyl-1 -propanol, Diethanolamine, 1 -Piperazineethanol, Diisopropanolamine, 2-(Methylamino)ethanol, 2- (Dimethylamino)ethanol, 1-Piperazineethanamine, 2-(Ethylamino)ethanol, (2- Hydroxyethyl)ethylenediamine, 1 -Methylpiperazine, 2-Methylpiperazine, 1,4-Piperazinediethanol, Diethylenetriamine, 3-Amino-1 -propanol, Piperidine, Ethylenediamine, Triethylenetetramine, N-Methyl- 1.3-propanediamine, 2,2-Dimethyl-1,3-propanediamine, (±)-1-Amino-2-propanol, Triethyl amine, Tetraethylenepentamine, Dabco, 1 -Ethylpiperazine, 2,2’-(1,2-Ethanediyldiimino)bis[ethanol], Putrescine, Morpholine, Diethylamine, Tris(2-aminoethyl)amine, (±)-2-Amino-1 -propanol, 2-Aminoethylpiperazine, 1.3-Diamino-2-propanol, Hexahydro-2, 4, 6-trimethyl-1, 3, 5-triazine, Propylenediamine, and mixtures thereof.

7. A method or process according to any of claims 3 to 6 wherein the metal is a monovalent, bivalent or trivalent metal, preferably wherein the metal is selected from group I or group II, more preferably wherein the metal is selected from lithium, sodium, potassium, beryllium, magnesium, calcium, strontium, and mixtures thereof, even more preferably wherein the metal is selected from sodium, potassium, magnesium, calcium and mixtures thereof.

8. A method or process according to any of claims 3 to 7 wherein the metal-containing surfactant comprises an anion selected from carboxylate, hydrocarbyl-substituted carboxylate, alkyl-substituted carboxylate, sulfate, hydrocarbyl sulfate, alkyl sulfate, ethoxylated hydrocarbyl sulfate, ethyoxylated alkyl sulfate, sulfonate, hydrocarbyl sulfonate, alkyl sulfonate, hydrocarbaryl sulfonate, alkaryl sulfonate, phenate, hydrocarbyl phenate, alkyl phenate, oligomeric or polymeric bridged phenate, oligomeric or polymeric hydrocarbyl bridged phenate, oligomeric or polymeric alkyl phenate, salicylate, hydrocarbylalkyl salicylate and mixtures thereof.

9. A method or process according to any of claims 3 to 8 wherein the metal-containing surfactant is selected from:wherein R is a linear, branched and / or cyclic; monomeric, oligomeric or polymeric; saturated, unsaturated or aromatic hydrocarbon of from 6 to 100 carbon atoms, preferably from 12 to 26 carbon atoms;\ / nwherein R is a linear, branched and / or cyclic; monomeric, oligomeric or polymeric; saturated, unsaturated or aromatic hydrocarbon of from 6 to 100 carbon atoms, preferably from 12 to 26 carbon atoms;wherein R is a linear, branched and / or cyclic; monomeric, oligomeric or polymeric; saturated, unsaturated or aromatic hydrocarbon of from 6 to 100 carbon atoms, preferably from 12 to 26 carbon atoms, and X is an integer from 1 to 5, preferably from 2 to 3;wherein R is a linear, branched and / or cyclic; monomeric, oligomeric or polymeric; saturated, unsaturated or aromatic hydrocarbon of from 6 to 100 carbon atoms, preferably from 12 to 26 carbon atoms;wherein R is a linear, branched and / or cyclic; monomeric, oligomeric or polymeric; saturated, unsaturated or aromatic hydrocarbon of from 6 to 100 carbon atoms, preferably from 8 to 80 carbon atoms, more preferably from 10 to 60 carbon atoms and even more preferably wherein R represents a linear, branched or polymeric hydrocarbon chain of from 20 to 40 carbon atoms;wherein R is a linear, branched and / or cyclic; monomeric, oligomeric or polymeric; saturated, unsaturated or aromatic hydrocarbon of from 6 to 100 carbon atoms, preferably from 4 to 30 carbon atoms, more preferably from 6 to 18 carbon atoms, and even more preferably from 8 to 16 carbon atoms;wherein R is a linear, branched and / or cyclic; monomeric, oligomeric or polymeric; saturated, unsaturated or aromatic hydrocarbon of from 6 to 100 carbon atoms, preferably from 4 to 30 carbon atoms, more preferably from 6 to 18 carbon atoms, and even more preferably from 8 to 16 carbon atoms; wherein y is an integer from 0 to 10, preferably from 1 to 8, more preferably from 2 to 7 and even more preferably from 3 to 6;wherein A is a divalent bridging group, preferably a hydrocarbyl group or sulfur, and more preferably sulfur; andwherein x is an integer from 1 to 4;wherein R is a linear, branched and / or cyclic; monomeric, oligomeric or polymeric; saturated, unsaturated or aromatic hydrocarbon of from 6 to 100 carbon atoms, preferably from 8 to 80 carbon atoms, more preferably from 10 to 60 carbon atoms, and even more preferably wherein R is a mixture of linear, branched or polymeric hydrocarbon chains of from 12 to 30 carbon atoms; and i. mixtures thereof;wherein M represents a metal ion of positive charge n, preferably wherein n is an integer from 1 to 4, more preferably wherein n is an integer from 1 to 3 and even more preferably wherein n is 1 or 2.

10. A method or process according to claim 9 wherein R is derived from at least one fatty acid or mixtures thereof, preferably wherein the fatty acid comprises at least one naturally-occurring fatty acid.

11. A method or process according to any preceding claim wherein the dispersion further comprises at least one additional surfactant.

12. A method or process according to claim 11 wherein at least one additional surfactant is a non-ionic surfactant.

13. A method or process according to claim 11 or 12 wherein at least one additional surfactant comprises a first surfactant and a second surfactant.

14. A method or process according to any of claims 11 to 13 wherein at least one additional surfactant comprises one or more lipophilic portions having a molecular weight of from greater than 450 g / mol to 50000 g / mol, preferably from 500 g / mol to 50000 g / mol, more preferably from 500 to 20000 g / mol, even more preferably from 550 g / mol to 5000 g / mol, even more preferably still from 600 g / mol to 2500 g / mol, yet further preferably from 650 g / mol to 1500 g / mol, and yet further preferably still from 700 g / mol to 1300 g / mol.

15. A method or process according to any of claims 11 to 14 wherein at least one additional surfactant comprises one or more lipophilic portions having a molecular weight of less than 50000 g / mol, less than 5000 g / mol, or less than 2500 g / mol, preferably from 100 g / mol to 1500 g / mol, more preferably from 120 g / mol to 1300 g / mol, and even more preferably from 150 g / mol to less than 700 g / mol, and / or wherein dependent on claim 13 or a claim dependent therefrom, the second additional surfactant comprises one or more lipophilic portions having a molecular weight less than the molecular weight of the one or more lipophilic portions of the first additional surfactant.

16. A method or process according to claim 13 and / or 15, wherein the molecular weight of the lipophilic portion(s) of at least one additional surfactant (and / or where dependent on claim 13 or a claim dependent therefrom, the first additional surfactant and / or the second additional surfactant) is a number average molecular weight.

17. A method or process according to any of claims 11 to 16, wherein at least one additional surfactant (and / or where dependent on claim 13 or a claim dependent therefrom, the first additional surfactant), has a hydrophilic-lipophilic balance calculated using Griffin’s Method, of from 0.1 to 8, preferably from 0.5 to 7, more preferably from 0.5 to 6, even more preferably from 0.5 to 5.5 and even more preferably still from 1 to 5.

18. A method or process according to any of claims 11 to 17, wherein:a. the additional surfactant (and / or where dependent on claim 13 or a claim dependent therefrom, thePF2025M002 / WGsecond additional surfactant) has a hydrophilic-lipophilic balance calculated using Griffin’s Method, of from 0.1 to 17, preferably from 1.8 to 16, more preferably from 3 to10, even more preferably from 3 to 6 and even more preferably still from 3 to 5; and / orb. the dispersion comprises water and the additional surfactant (and / or where dependent on claim 13 or a claim dependent therefrom, the second additional surfactant) has a hydrophilic-lipophilic balance calculated using Griffin’s Method, of from 10 to 17, from 11 to 17, from 12 to 17, from 13 to 17, from 14 to 17, from 10 to 16, from 11 to 16, from 12 to 16, from 13 to 16 or from 14 to 16.

19. A method or process according to any of claims 11 to 18 wherein at least one additional surfactant (and / or where dependent on claim 13 or a claim dependent therefrom, the first additional surfactant and / or second additional surfactant) comprises one or more olefin polymers, functionalised with at least one polar functional group.

20. A method or process according to any of claims 11 to 19 wherein at least one additional surfactant (and / or where dependent on claim 13 or a claim dependent therefrom, the first additional surfactant and / or second additional surfactant) comprises the reaction product or mixture of a poly(olefin) succinic acid and / or poly(olefin) succinic anhydride with an organic amine or alkanolamine.

21. A method or process according to claim 20 wherein the organic amine or alkanolamine comprises primary amine functionality.

22. A method or process according to claim 20 or 21 wherein the organic amine or alkanolamine is selected from N-Methyldiethanolamine, Monoethanolamine, 2-Amino-2-methyl-1 -propanol, Diethanolamine, 1- Piperazineethanol, Triethanolamine, Diethylethanolamine, Diisopropanolamine, Diglycolamine, 2- (Methylamino)ethanol, 2-(Dimethylamino)ethanol, 1-Piperazineethanamine, 2-(Ethylamino)ethanol, (2- Hydroxyethyl)ethylenediamine, 1,4-Piperazinediethanol, Diethylenetriamine, 3-Amino-1 -propanol, Triethylenetetramine, (±)-1-Amino-2-propanol, Tetraethylenepentamine, 2, 2’, -(1,2- ethanediyldiimino)bis[ethanol], Tris(2-aminoethyl)amine, (±)-2-Amino-1 -propanol, 2- Aminoethylpiperazine, or mixtures thereof; preferably wherein the organic amine is selected from N- Methyldiethanolamine, Monoethanolamine, Diethanolamine, 1 -Piperazineethanol, Diethylethanolamine, 1-Piperazineethanamine, Tetraethylenepentamine or mixtures thereof.

23. A method or process according to any of claims 20 to 22 wherein the poly(olefin) succinic acid or anhydride is selected from poly(isoprene) succinic acid, poly(isoprene) succinic anhydride, poly(isobutene) succinic acid, poly(isobutene) succinic anhydride or a mixture or combination thereof, preferably wherein the poly(olefin) succinic acid or anhydride is poly(isobutene) succinic acid or poly(isobutene) succinic anhydride.

24. A method or process according to any of claims 11 to 23 wherein at least one additional surfactant (and / or where dependent on claim 13 or a claim dependent therefrom, the first additional surfactant and / or second additional surfactant) comprises the reaction product or mixture of:with b: one or more organic amines selected from; Monoethanolamine, N-(2- hydroxyethyl)ethylenediamine), 1 -Piperazineethanol, Diethylethanolamine, 1 -Piperazineethanamine, Tetraethylenepentamine, Pentaethylenehexamine, Hexaethyleneheptamine, or mixtures thereof; wherein n is a positive integer from 7 to 900, preferably from 8 to 350, more preferably from 9 to 90, even more preferably from 10 to 45, even more preferably still from 11 to 27, and further preferably from 12 to 23;and preferably wherein the one or more organic amines comprise, or the organic amine is, diethylethanolamine.

25. A method or process according to any of claims 20 to 24 wherein the organic amine comprises at least one primary or secondary aminic functional group and wherein at least one additional surfactant (and / or where dependent on a claim dependent from claim 13, the first additional surfactant and / or second additional surfactant) is further reacted with urea, one or more aldehydes, one or more ketones, one or more carboxylic acids, one or more hydrocarbon-substituted succinic anhydrides, maleic anhydride, one or more epoxides, one or more carbonate esters and / or ethylene carbonate.

26. A method or process according to any of claims 11 to 25, wherein at least one additional surfactant (and / or where dependent on claim 13 or a claim dependent therefrom, the first additional surfactant and / or second additional surfactant, preferably the second additional surfactant), comprises a structure selected from:owherein m is an integer from 2 to 24 and Ri is a hydrocarbon moiety;x and y are each integers, the sum of x and y is from 2 to 6 and m is an integer from 1 to 70;wherein R is a hydrocarbon moiety with from 2 to 20 carbon atoms and m is an integer from 2 to 70;Ywherein W, X, Y and Z are each independently selected from poly(ethylene oxide) and poly(propylene oxide) moieties;PF2025M002 / WGe.wherein n1 and n2 are each integers and the sum of n1 and n2 is in the range of from 2 to 80;wherein x is an integer from 1 to 3, y is an integer from 1 to 3 and R is a carboxylic acid esterified with one of the hydroxyl groups;wherein w, x, y and z are each integers, the sum of w, x, y and z is from 10 to 100 and R is a carboxylate moiety.

27. A method or process according to any of claims 11 to 26 wherein at least one additional surfactant is present in an amount of from 0.1 % to 10%, from 0.2% to 9.5%, from 0.5% to 9%, from 1 % to 8%, from 1.5% to 7%, from 1.7% to 6%, from 2% to 4.5%, from 2.2% to 4%, or from 2.5% to 3%, by weight of the dispersion.

28. A method or process according to any preceding claim wherein the oleaginous medium comprises or consists of one or more Group I base stocks, Group II base stocks, Group III base stocks, Group IV base stocks, preferably Group IV.

29. A method or process according to any preceding claim wherein the oleaginous medium has an initial boiling point of at least 120°C, preferably at least 140°C, more preferably at least 160°C and more preferably still at least 180°C.

30. A method or process according to any preceding claim wherein the oleaginous medium has a kinematic viscosity at 40 °C of below 50 cSt, below 30 cSt, below 10 cSt, below 5 cSt, below 2 cSt, below 1 cSt, from 0.1 cSt to 10 cSt, from 0.25 cSt to 5 cSt, from 0.3 cSt to 2.5 cSt, from 0.4 cSt to 2 cSt or from 0.5 cSt to 1 cSt.

31. A method or process according to any preceding claim wherein the acidic gas separated from the gaseous mixture comprises, or is, carbon dioxide.

32. A method or process according to any preceding claim wherein the at least one organic base forms an internal phase in the oleaginous medium, preferably wherein the surfactant forms a boundary layer between the organic base and the oleaginous medium.

33. A method or process according to any preceding claim wherein the organic base is present in an amount of from 5% to 49%, preferably from 10% to 47%, more preferably from 20% to 46%, even more preferably from 30% to 45% and even more preferably still from 40% to 45%, by weight of the dispersion.

34. A method or process according to any preceding claim wherein the oleaginous medium is present in an amount of from 10% to 90% by weight of the dispersion, preferably from 20% to 80%, more preferably from 30% to 70%, even more preferably from 40% to 60% and even more preferably still from 45% to 55%, by weight of the dispersion.

35. A method or process according to any preceding claim wherein the ionic surfactant is present in an amount from 0.1 % to 10%, from 0.25% to 5%, from 0.3% to 4.5%, from 0.4% to 4%, from 0.5% to 3%, from 0.7% to 2% or from 1 % to 1.5%, by weight of the dispersion.

36. A method or process according to any preceding claim wherein the total amount of surfactant present in the composition is from 0.1% to 20%, from 0.2% to 15%, from 0.5% to 10%, from 1% to 8%, from 1.5% to 7%, from 2% to 6% or from 3% to 5%, by weight of the dispersion.

37. A method or process according to any preceding claim, the method or process further comprising one or more of the steps of:a. removing the gaseous mixture from contact with or introduction to the dispersion,b. transferring the dispersion to a desorber, and / orc. heating the dispersion, preferably to a temperature from 20 °C to 100 °C above the dispersion temperature when the gaseous mixture contacted the dispersion, more preferably to a temperature from 25 °C to 80 °C greater, even more preferably to a temperature from 30 °C to 70 °C greater, even more preferably still from 35 °C to 60 °C greater, and yet more preferably from about 40 °C to about 50 °C greater, to release the separated acidic gas;after contacting the gaseous mixture with the dispersion.

38. A composition for separating acidic gases from a gaseous mixture comprising such acidic gases, the composition comprising a dispersion of at least one labile organic base in an oleaginous medium, the dispersion further comprising an ionic surfactant, preferably wherein the dispersion is further defined in accordance with any of claims 3 to 35.

39. A system for separating acidic gases from a gaseous mixture comprising such acidic gases, comprising a vessel with means for fluid introduction and removal, wherein the vessel contains a composition according to claim 38.

40. Use of a composition comprising a dispersion of at least one organic base and an oleaginous medium, the composition further comprising an ionic surfactant to separate acidic gases from a gaseous mixture containing such acidic gases.

41. Use according to claim 40, wherein the acidic gas separated from the gaseous mixture comprises, or is, carbon dioxide.

42. Use of a composition comprising a dispersion of at least one organic base in an oleaginous medium, the composition further comprising an ionic surfactant, for the capture of carbon dioxide from a gaseous mixture comprising carbon dioxide.

43. Use according to any of claims 40 to 42 wherein the dispersion is defined in accordance with any of claims 3 to 36.

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