Catalyst and process for low carbon intensity diesel fuel production

Abstract

A method of reactive CO2 capture to produce low carbon intensity (CI) diesel fuel includes capturing CO2 from a flue gas using a capture medium; combining the captured CO2 in the capture medium, an alcohol, and an olefin in a reactor; and catalyzing, in the reactor, an alkoxycarbonylation reaction between the CO2, the alcohol, and the olefin using a catalyst to produce the low CI diesel fuel.

Description

CATALYST AND PROCESS FOR LOW CARBON INTENSITY DIESELFUEL PRODUCTIONFIELD OF THE INVENTION

[0001] This invention relates to the production of low-carbon intensity diesel fuel from CO2 and olefins.BACKGROUND

[0002] This section is intended to introduce the reader to various aspects of art that may be related to the present disclosure, which are described and / or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

[0003] The transportation sector is one of the key sectors responsible for greenhouse gas (GHG) emissions. Major items that contribute to overall transportation GHG emissions include but are not limited to: vehicle efficiency (e.g., mpg), fuel carbon intensity (CI), and vehicle fleet mile traveled (VMT). Thus, lowering any one or a combination of these items could contribute to a reduction in GHG emissions by the transportation sector.

[0004] There continues to be an increasing need for a wide range of fuels in the transportation sector, and this need generally grows in correlation with the growth of the transportation sector. Thus, low CI fuels may be a key contributor to lowering future transportation emissions. Carbon intensity (CI) is a measure of carbon dioxide and other greenhouse gases that are emitted or released (gCChe, grams of CO2 equivalent) per unit of energy (MJ). For instance, the measure of the carbon intensity of a product may be given in units of gCChe / MJ of product, or grams of CO2 equivalent per megajoule of product (since products have a calorific value). Thus, in the context of fuels, the CI of a particular fuel accounts for not only the emissions released from the use of the fuel, but also the emissions associated with making the fuel.

[0005] Reducing the carbon intensity of fuels can involve different approaches such as: producing fuel from renewable sources (e.g., biofuels), producing co-processed fuels, using electricity to power electric vehicles (the CI of which will depend on the source of the electricity), or using hydrogen as a fuel, to name a few. At present, low CI fuels such as these may be associated with high costs, low availability, and limited infrastructure associated with their production and transport. Despite studies of new ways to make and use these fuels, there continues to be a strong need for methods and materials capable of enhancing the production and availability of low CI fuels.SUMMARY

[0006] A summary of certain embodiments disclosed herein is set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of these certain embodiments and that these aspects are not intended to limit the scope of this disclosure. Indeed, this disclosure may encompass a variety of aspects that may not be set forth below.

[0007] Certain embodiments of this disclosure are directed to the production of low carbon intensity diesel fuel via the reactive capture of CO2. In one embodiment, for example, a method of reactive CO2 capture to produce low carbon intensity (CI) diesel fuel includes capturing CO2 from a flue gas using a capture medium; combining the captured CO2 in the capture medium, an alcohol, and an olefin in a reactor; and catalyzing, in the reactor, an alkoxycarbonylation reaction between the CO2, the alcohol, and the olefin using a catalyst to produce the low CI diesel fuel.

[0008] In another embodiment, for example, a system for reactive CO2 capture to produce low carbon intensity (CI) diesel fuel includes a CO2 flow path extending from a source of flue gas and to an alkoxycarbonylation reactor, and a CO2 capture vessel positioned along the CO2 flow path and configured to receive a capture medium from a capture medium source and to mix the flue gas with the capture medium and thereby allow the capture medium to capture CO2 contained within the flue gas to produce a captured CO2 stream and a CCh-lean exhaust gas stream. The system also includes one or more injection points configured to introduce an olefin and an alcoholinto the CO2 flow path, and the alkoxycarbonylation reactor positioned along the CO2 flow path. The alkoxy carbonylation reactor is configured to receive the captured CO2 in the capture medium, the olefin, and the alcohol, wherein the alkoxycarbonylation reactor comprises a catalyst configured to catalyze an alkoxycarbonylation reaction between the olefin, the alcohol, and the captured CO2 to produce the low CI diesel fuel.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] These and other objects, features and advantages of the present disclosure will become better understood with reference to the following description, appended claims and accompanying drawings, wherein:

[0010] FIG 1 is a flow diagram of a single-step process for low carbon intensity Diesel fuel production from CO2, renewable EtOH, and olefin via alkoxycarbonylation, in accordance with an embodiment of this disclosure;

[0011] FIG 2 is a schematic diagram of the reactive capture of CO2 using ionic liquids and catalytic conversion of long chain olefins to low CI diesel components, in accordance with an embodiment of this disclosure;

[0012] FIG. 3 is a diagram of a two-step process for low carbon intensity diesel fuel production from CO2, H2, and olefin via methanol synthesis and etherification, in accordance with an embodiment of this disclosure;

[0013] FIG. 4 is a diagram of a process for low carbon intensity diesel fuel production from CO2, H2, and olefin via carbonylation, methanol synthesis, and esterification, in accordance with an embodiment of this disclosure; and

[0014] FIG 5 is a diagram of a process for low CI Diesel production from CO2, H2, and olefin via a reverse water-gas shift reaction, carbonylation, and esterification, in accordance with an embodiment of this disclosure.DETAILED DESCRIPTION

[0015] Carbon capture, utilization, and storage (CCUS) is generally a process intended to reduce the level of carbonaceous gases (most commonly carbon dioxide (CO2)) within the atmosphere. This may include the capture of carbonaceous gases from sources of emissions so that they do not enter the atmosphere. In some instances, the captured gases may be used in other processes, such as in the production of new materials, chemicals, and so forth, or as a process gas.

[0016] CCUS in general may afford operators in the oil and gas industry an opportunity to enhance efficiencies while also reducing carbon intensity in their operations. For example, reactive capture is a process in which CO2 is captured and subsequently converted into a product. Reactive capture methods may involve the use of a capture agent to capture the CO2 from a mixture, such as a product mixture, an effluent stream, and so forth. In reactive capture methods, the CO2 is generally not separated from the capture agent, which may afford greater efficiencies for integrated processes. The use of reactive capture to produce products from captured CO2 is thus an opportunity to produce low CI products.

[0017] It is now recognized that it may be possible to reduce the carbon intensity of fuels by using low-value feedstocks such as CO2 and olefin-containing streams available from refineries, petrochemical complexes, and other petrochemical plants. If the olefins have a certain carbon length (e.g., from Cs to C20), the diesel generated (b.p. 325-675 °F) from these olefins would be a low CI diesel fuel.

[0018] In accordance with certain embodiments of this disclosure, carbon dioxide (CO2) is recovered from refinery flue gases using a conventional separation technology process, so the CO2 is not released to the atmosphere with the concomitant reduction of GHG emissions. In some embodiments the CO2 may be subsequently reacted with an olefin and an alcohol to produce low CI diesel fuel. In other embodiments the CO2 may be converted into an alcohol, which is subsequently reacted with the olefin to produce low CI diesel fuel.

[0019] FIG. 1 is a process flow diagram depicting a reactive capture process 10 for making low CI diesel fuel 12 using captured CO2. In the depicted embodiment a CCh-containing stream 14 is sent to a CO2 separation process 16 to produce a separated CO2 stream 18. The CCh-contianingstream 14 may include, by way of non-limiting example, a flue gas stream generated within a refinery or petrochemical plant. The CO2 separation process 16 may include, by way of nonlimiting example, an adsorption process, an absorption process, a membrane separation process, or any combination thereof. Generally, the CO2 separation process 16 enriches the separated CO2 stream 18 in CO2 relative to the CCh-containing stream 14. The separated CO2 stream 18 may, in some embodiments, be a stream including at least some of the CO2 from the CCh-containing stream 14 along with a capture medium used to capture the CO2 from the CCh-containing stream 14. The capture medium may be a solid, a liquid, a dissolved or suspended species, or any combination thereof.

[0020] The separated CO2 stream 18, along with an olefin-containing stream 20 and an alcohol 22 are provided to an alkoxycarbonylation reaction 24, typically performed within one or more reactors. The alkoxy carbonylation reaction 24 may be catalyzed using a catalyst system according to scheme 1 depicted below:Scheme 1. Catalyzed Alkoxy carbonylation of Olefin

[0021] In Scheme 1, an alpha olefin, CO2, an alcohol, and a catalyst system are used to produce an ester, with R and R’ being alkyl chains of appropriate length such that the ester product is the low CI diesel fuel 12. While other reactions may take place and other products may be formed, in accordance with this disclosure the reagents and conditions are controlled such that the predominant reaction product is the ester (or esters, depending on the nature of the reagents) as shown in Scheme 1. Conditions of the reaction include but are not limited to reagent concentrations, reaction temperature (e.g., between 25 and 200 °C), CO2 pressure (e.g., between 1 and 40 bar), and residence / reaction time (e.g., between 1 and 6 hours).

[0022] The alcohol 22 may be synthetic or renewable, and may include methanol, ethanol, propanol, butanol, or other alcohols, or any combination thereof. With reference to scheme 1, R’ may be an alkyl chain having between 1 and 8 carbons. More generally, the alcohol 22 may have between 1 and 8 carbons, for example. In one embodiment, the alcohol 22 is methanol. In anotherembodiment, the alcohol 22 is renewable ethanol. In still further embodiments, the alcohol may be synthesized at the same refinery or petrochemical plant that generates the CCh-containing stream 14.

[0023] The olefin-containing stream 20 may be a stream generated at a refinery or petrochemical plant, such as the same refinery or petrochemical plant that generates the CCh-containing stream 14. As non-limiting examples, the olefin-containing stream 20 may be streams coming from propylene oligomerization units, polyethylene and polypropylene-production facilities, alkylbenzene detergent plants, poly alpha olefin lubricant installations, and alkyl amines- generating plants. The olefin-containing stream 20 may include, by way of non-limiting example, one or more olefins having between 8 and 24 carbons (e.g., R in scheme l is a carbon chain having between 7 and 19 carbons). In some embodiments, the one or more olefins include one or more alpha olefins. By way of non-limiting example, the one or more olefins may have the formula CH3-(CH2)n-CH=CH2, where n is an integer between 5 and 20. By way of further non-limiting example, the one or more olefins may include a terminal alkene such as propylene tetramer or propylene pentamer, as shown in structures 1 and 2, respectively.

[0024] The alkoxy carbonylation catalyst system used in the alkoxy carbonylation reaction 24 may be homogenous, biphasic, immobilized, or supported (e.g., as in a slurry). In some embodiments the alkoxycarbonylation catalyst system may include a metal such as alkali metals, alkali earth metals, or transition metals. Organometallic alkoxycarbonylation catalyst systems may include ligands, such as nitrogen-containing ligands, phosphorous-containing ligands, or ligands containing both nitrogen and phosphorous atoms. The ligands may be monodentate, bidentate, or polydentate ligands. In certain embodiments, the alkoxycarbonylation catalyst system includes a ruthenium catalyst, such as a ruthenium (II) catalyst. By way of non-limiting example, the alkoxycarbonylation catalyst system may include RU2(CO)I2, or chloral hydrate ruthenium, Fe3(CO)i2, Co2(CO)s, and / or combination thereof. In another embodiment, the catalyst systems may contain a co-catalyst to improve activity and stability. Such co-catalysts may include lowmolecular weight oxygenate compounds such as formates that may promote a more active catalyst under the experimental conditions described herein. In some embodiments of this disclosure, the activity and selectivity of the alkoxy carbonylation catalyst system for promoting formation of the desired low CI diesel fuels (e.g., the ester shown in Scheme 1) may be enhanced by the capture medium used to capture CO2 from the CCh-containing stream 14, as described in further detail herein.

[0025] FIG. 2 is a schematic diagram depicting an example embodiment of a reactive CO2 capture (RCC) system 40 for carrying out the reactive CO2 capture process 10 of FIG. 1 to produce low CI diesel fuel 12. In this embodiment, the RCC system 40 receives a flue gas 42 from another part of the refinery or petrochemical plant in which the RCC system 40 is located. The flue gas 42 includes CO2, as well as other products of combustion such as nitrogen, water vapor, CO, and others. The RCC system 40 includes a CO2 flow path 44, which extends from a source of the flue gas 42, through a capture vessel 46 (a CO2 capture vessel), and to an alkoxycarbonylation reactor 48 where CO2 captured from the flue gas 42 is ultimately reacted. In this way, the CO2 flow path 44 carries CO2, either as a mixture with other flue gas components or as a separated component, through the system 40.

[0026] More specifically, the capture vessel 46 of the RCC system 40 receives the flue gas 42 along the CO2 flow path 44, and mixes the flue gas 42 with a capture medium 50 to perform the CO2 separation process 16 of FIG. 1 to generate the separated CO2 stream 18 and a CCh-lean exhaust gas 52. The capture medium 50, as noted above with respect to FIG. 1, is configured to capture at least some of the CO2 from the flue gas 42, and may include a solid, a liquid, a dissolved or suspended species, a permeable membrane, or any combination thereof.

[0027] In some embodiments the capture medium 50 is configured to preferentially absorb or adsorb CO2 over other constituent gases in the flue gas 42. By way of non-limiting example, the capture medium 50 may include an ionic liquid, an ionic liquid supported on a solid support such as silica, alumina, silica-alumina, zeolites, zirconia, molecular sieves, or polymers. The capture medium 50 may additionally or alternatively include metal nanoparticles (e.g., based on Ca, Mg, or Al) stabilized with ionic liquid, polymerized ionic liquids, nitrogen-containing polymers, nanoparticles based on Ca, Mg, or Al supported on solids such as silica, silica-alumina, molecularsieve, and petcoke. In further embodiments the capture medium 50 may include an aqueous biphasic system including transition metal water-soluble catalysts having ligands based on: (i) sulfonates, phosphines, (ii) carboxylic acids, (iii) a combination of phosphonic, carboxylic ligands, or nitrogen-based ligands; and transition metal complexes based on: Ru, Rh, Ni, Co, Fe, Pd, Mn, Co, Cu, Mo, or any combination thereof; and water-soluble nanoparticles.

[0028] The capture medium 50 may in some embodiments include an adsorbent. In some embodiments, the capture vessel 46 may represent a capture process that utilizes multiple vessels or subsystems for separating and capturing CO2, such as a combination of membrane-based gas separation and a liquid medium for absorbing separated CO2. In embodiments where the capture vessel 46 uses a mobile capture medium 50, the capture vessel 46 may be fluidly coupled with a source (not shown) of the capture medium 50, such as a storage tank containing the capture medium 50.

[0029] In accordance with some embodiments of this disclosure, the capture medium 50 may include materials that aid in the alkoxycarbonylation reaction. Capture media 50 that aid in the alkoxycarbonylation reaction may include one or more ionic liquids. Some of the ionic liquids and mixtures thereof may offer superior facilitation of the catalytic alkoxy carbonylation reaction relative to others, as discussed in the examples of this disclosure.

[0030] The one or more ionic liquids of the capture medium 50 may include alkyl imidazolium- based ionic liquids. That is, the one or more ionic liquids may include an alkyl imidazolium cation. Examples of alkyl imidazolium cations include but are not limited to l-butyl-3 -methyl imidazolium (BMelm) cation, l-ethyl-3 -methyl imidazolium (EMelm) cation, l-hexyl-3 -methyl imidazolium (HeMelm) cation, or l-methyl-3 -octyl imidazolium (MOctlm) cation.

[0031] The one or more ionic liquids may include anions such as halides, tritiates, sulfates, borates, imides, and so forth. Non-limiting examples include chloride (Cl), bromide (Br), bis(trifluoromethanesulfonyl)imide, acetate, and tetrafluoroborate.

[0032] As shown, the capture vessel 46 and alkoxycarbonylation reactor 48 are coupled via the CO2 flow path 44. In this embodiment, the captured CO2 stream 18 is transmitted along the CO2 flow path 44 from the capture vessel 46 and to the alkoxy carbonylation reactor 48. Generally, theseparated CO2 stream 18 is enriched, relative to the flue gas 42, in CO2. In some embodiments, the separated CO2 stream 18 includes a mixture of the separated CO2 from the flue gas and ionic liquid used as the capture medium 50. Using the ionic liquid as a capture medium and as a facilitator for the alkoxy carbonylation reaction may improve efficiencies of the system 40.

[0033] As illustrated, the system 40 may include one or more injection points located along the CO2 flow path 44 between the capture vessel 46 and the alkoxycarbonylation reactor 48 to introduce alcohol and olefin into the CO2 flow path 44. Additionally or alternatively, in some embodiments one or more injection points may be located at the alkoxy carbonylation reactor 48 for introducing the olefin, or the alcohol, or both. In this way, the CO2 flow path 44 and / or the alkoxy carbonylation reactor 48 may have a fluid connection to an alcohol source 54 and an olefin source 56.

[0034] The alkoxycarbonylation reactor 48 is thus configured to receive the captured CO2 in the capture medium 50, the olefin-containing stream 20, and the alcohol 22. The alkoxy carbonylation reactor 50, as depicted, includes a catalyst 58 configured to catalyze the alkoxycarbonylation reaction 24 described with respect to FIG. 1 to produce the low CI diesel fuel 12. As described above, conditions within the alkoxycarbonylation reactor 48 may be controlled to facilitate the formation of the ester product, and such conditions may include but are not limited to CO2 pressure, reagent concentration, reagent composition, residence time within the reactor 48, and temperature.

[0035] The desired low CI diesel fuel product will generally be present within the alkoxycarbonylation reactor 48 as part of a mixture that also includes unreacted reagents (e.g., CO2, alcohol) and the capture medium 50. Generally, all of the olefin reagent will be consumed but in some embodiments some may remain unreacted that later can be recycled to the reactor 48.

[0036] To facilitate process efficiency and to enhance the concentration of the desired low CI diesel fuel product, the system 40 also includes a separation system 60 fluidly coupled to and downstream of the alkoxy carbonylation reactor 48. Specifically, in the illustrated embodiment the alkoxycarbonylation reactor 48 and the separation system 60 are fluidly coupled along a product flow path 62 such that the separation system 60 receives effluent from the alkoxycarbonylation reactor 48. The separation system 60 may include one or more separation stages, illustrated inFIG. 2 as including a first separation stage 64 and a second separation stage 66, configured to generate recycle streams to recycle reagents and capture media back to the alkoxycarbonylation reactor 48 and to purify the low CI diesel fuel 12.

[0037] The first separation stage 64 is configured to separate unreacted CO2, unreacted olefin, and alcohol from the reactor effluent to produce a first recycle stream 68 and a first product stream 70. The first recycle stream 68 is depleted, relative to the reactor effluent, in the capture medium and the low CI diesel fuel and enriched, relative to the reactor effluent, in the unreacted CO2 and alcohol. The first recycle stream 68 may be transmitted along a first recycle flow path 72 from the first separation stage 64 back to the alkoxycarbonylation reactor 48. The first product stream 70 is enriched, relative to the reactor effluent, in the capture medium and the low CI diesel fuel and depleted, relative to the reactor effluent, in the unreacted CO2 and alcohol. The first product stream 70 may continue along the product flow path 62 to the second separation stage 66.

[0038] The second separation stage 66 of the separation system is configured to receive the first product stream 70 from the first separation stage 64, and is configured to separate the capture medium from the low CI diesel fuel to produce a second recycle stream 74 and the low CI diesel fuel 12, which may be considered a second product stream. The second recycle stream 74 is depleted, relative to the first product stream 70, in the low CI diesel fuel and enriched, relative to the first product stream 70, in the capture medium 50. The second recycle stream 74 (essentially the capture medium 50) is transmitted along a second recycle flow path 76 from the separation system 60 to the alkoxy carbonylation reactor 48.

[0039] Other embodiments of this disclosure may include a two-step process 80 to produce low carbon intensity diesel fuels 12, as shown in FIG. 3. The process 80 as illustrated may include catalyzed alcohol (e.g., methanol) synthesis 82 from CO2 84 and hydrogen (H2) 86 with subsequent etherification 88 of the produced alcohol 90 (e.g., methanol) with an olefin containing stream (e.g., the olefin-containing stream 20).

[0040] In some embodiments, the CO2 84 may be produced in the same refinery or petrochemical plant in which the process 80 is conducted. For example, the CO2 84 may be CO2 contained within a flue gas, or CO2 separated or captured from a flue gas. In one embodiment, the CO2 84 may besimilar to the separated CO2 stream 18 of FIG. 1 (e.g., a stream including the CO2 and a capture medium).

[0041] The catalyzed methanol synthesis 82 in FIG. 3 may be catalyzed using a metal catalyst, such as a mixed metal catalyst. In one embodiment, the catalyst is a Cu-Zn catalyst.

[0042] The process 80 also includes combining the produced alcohol 90 (e.g., methanol) with a suitable olefin source (e.g., the olefin-containing stream 20) and an acid catalyst to promote the etherification reaction 88, leading to the formation of low carbon intensity diesel fuel 12. The acid catalyst may include, for example, sulfonated resins or zeolites having a suitable acidity for promoting the etherification reaction. An example of the chemical reactions of FIG. 3 is shown in Scheme 2.Scheme 2. An example of the chemical reactions to produce low CI diesel fuel as depicted in FIG. 3.

[0043] In Scheme 2, the olefin may have a chain length such that n is between 10 and 20. Further, in some embodiments other alcohols may be used in combination with or in place of the synthesized alcohol (e.g., methanol), such as ethanol, propanol, or butanol.

[0044] The catalyzed methanol synthesis process 82 of FIG. 3 may be combined with other processes to produce ester-based low CI diesel fuels 12. For example, as depicted in FIG. 4, a process 100 may include a combination of catalyzed carbonylation 102, the catalyzed methanol synthesis 82, and esterification 104 to produce the low CI diesel fuels 12. Additionally or alternatively, other sources of alcohols may be used in the esterification reaction 104. In this way, the process 100 of FIG. 4 may be considered a two-step method of producing low CI diesel fuel 12.

[0045] In a first step, the CO2 84 and the olefin-containing stream 20 having olefins of suitable chain length are combined with a metal catalyst to generate a carboxylic acid via the carbonylation reaction 102. The carbonylation catalyst system can be homogenous, biphasic, immobilized, and supported catalysts containing alkali, alkali earth, transition metals, non-metal, organo-catalysts, and combinations. The catalyst may contain nitrogen- or phosphorous-containing ligands.

[0046] Process conditions for the carbonylation reaction 102 may be controlled to preferentially produce a carboxylic acid 106. The operational envelope for such production may include a reaction temperature in the range of 25-200 °C, a CO2 pressure of between 1 and 40 bar, and a residence time in the reactor (in which the carbonylation reaction 102 is conducted) of between 1 and 6 h.

[0047] In a second step, methanol or other alcohol (from the methanol synthesis 82) is combined with the carboxylic acid 106 to promote the esterification reaction 104 in the presence of an acid catalyst. The acid catalyst includes but is not limited to any esterification promoting catalyst with a solid surface, organic, or inorganic entity with pkA < 14 or equivalent acidity strength, such as sulfonated resins, acid functionalized polymers, silica, alumina, silica-alumina or zeolites leading to the desired product.

[0048] An example of the chemical reactions of the process 100 is provided in Scheme 3. As noted, other alcohols such as ethanol (e.g., renewable ethanol), propanol, or butanol, may be used in addition to or in lieu of methanol. In Scheme 3, the length of the carbon chain (n) may be from 10 to 20.Scheme 3. An example of the chemical reactions used to produce low CI diesel fuels depicted in FIG. 4.

[0049] In some embodiments, certain steps of the process of FIG. 4 may be combined with other processes as shown in FIG. 5. In particular, FIG. 5 depicts a process 120 of combining a reverse water gas shift reaction 122 with the carbonylation and esterification reactions 102, 104 described herein to produce the low CI diesel fuel 12. In the process 120, the reverse water-gas shift reaction 122 uses the CO2 84 and the hydrogen (H2) 86 to produce a stream of CO and H2O 124.

[0050] In turn, one or more olefins from the olefin-containing stream 20 is added to generate the carboxylic acid 106 in the carbonylation reaction 102. In the third step of the process 120, the low CI diesel 12 is produced by esterification of the carboxylic acid 106 with the alcohol 22 (e.g., renewable ethanol, methanol, or others).EXAMPLES

[0051] Unless indicated to the contrary, the alkoxy carbonylation processes of each of the following examples were carried out in a 100- or 300-ml autoclave, batch type, with mechanical stirring at 300 rpm and temperature-controlled heating unit with a total reaction volume of 40-80 ml. The reactor was loaded with CO2 at room temperature and heated to the desired temperature. After 6-16 hours of reaction for each process, the autoclave was allowed to cool to room temperature and was depressurized. GC-MS analyses of the reactions were performed as a monitoring technique to determine the ester formation among other products. The esters produced in the catalytic reactions are the low carbon intensity (low CI) diesel fuels. The Conv. (%) refers to the percentages of olefin converted to products.Example 1

[0052] 0.064 g of Ru3(CO)i2 was mixed with 3.5 g of l-butyl-3-methyl-imidazolium chloride (BMelmCl), 1.2 g of 1-Octene, and 19.3 g of methanol in a FTFE vessel. The mixture was introduced into the autoclave (100 ml), loaded with CO2 (40 atm), and heated to 160 °C for 16h. After cooling down, the mixture was analyzed by GC-MS, indicating 1-octene conversion of 100 %, ester formation, 80 ± 5 %, olefin isomerization, 12 ± 3 %, octane 8 ± 2 %Example 2

[0053] 0.064 g of Ru3(CO)i2 was mixed with 4.2 g of l-ethyl-3 -methyl imidazolium chloride (EMelmCl), 1.2 g of 1-Octene, and 20 ± 1 g of methanol in a FTFE vessel. The mixture was introduced into the autoclave (100 ml), loaded with CO2 (40 atm), and heated to 160 °C for 16 h. After cooling down, the mixture is analyzed by GC-MS, indicating 1-octene conversion of 100 %, ester formation, 90 ± 2 %, olefin isomerization, 6 ± 2 %, octane 4 ± 1 %Example 3 (Ionic Liquid (IL) loading)

[0054] 0.064 g of Ru3(CO)i2 was mixed with l-Butyl-3 -Methyl Imidazolium chloride (BMelmCl, 3.5 g to 7.2 g), 1.2 g of 1-Octene, and 20 ± 1 g of methanol in an FTFE vessel. The mixture was introduced into the autoclave (100 ml) loaded with CO2 (40 atm) and heated to 160 C for 16 h. After cooling down, the mixture is analyzed by GC-MS. Results are shown in Table 1.Table 1. Alkoxycarbonylation reaction: effect of BMelmCl loading.Conv. Ester productionReaction BMelmCl (g)(%) (%)1 3.55 100 81.972 4.5 99.98 81.373 7.1 99.98 66.74Example 4 (IL loading)

[0055] 0.064 g of Ru3(CO)i2 was mixed with l-Ethyl-3-Methyl-Imidazolium chloride (EMelmCl , 2.9 g to 5.9 g), 1.2 g of 1-Octene, and 20 ± 1 g of methanol in an FTFE vessel. The mixture was introduced into the autoclave (100 ml), loaded with CO2 (40 atm), and heated to 160°C for 16 h. After cooling down, the variety is analyzed by GC-MS. Results are shown in Table 2.Table 2. Alkoxy carbonylation reaction: effect of EMelmCI loading.Conv. Ester productionReaction EMelmCI (g)(%) (%)1 2.95 99.85 85.92 4.25 99.90 89.353 5.95 99.70 77.35Example 5 (Effect of the IL cation)

[0056] 0.064 g of Ru3(CO)i2 was mixed with the corresponding alkyl-imidazolium IL (2.9 g to 4.6 g), 1.2 g of 1-Octene, and 20 ± 1 g of methanol in an FTFE vessel. The mixture was introduced into the autoclave (100 ml), loaded with CO2 (40 atm), and heated to 160 °C for 16 h. After cooling down, the variety is analyzed by GC-MS. Results are shown in Table 3.Table 3. Alkoxy carbonylation reaction: effect of Imidazolium cation„ R1,R2- . . Ester productionReaction .. Alkyl position Conv. (%) ,Imidazolium (%}1 BMe l-Butyl-3-Methyl 100 76.32 Eme l-Ethyl-3-Methyl 99.79 68.553 HeMe l-Hexyl-3-Methyl 99.60 73.604 Moct l-Metyl-3-Octyl 98.45 12.76Example 6 (Effect of the IL anion)

[0057] 0.064 g of Ru3(CO)i2 was mixed with the corresponding alkyl-imidazolium, IL (2.9 g to 4.6 g), 1.2 g of 1-Octene, and 20 ± 1 g of methanol in an FTFE vessel. The mixture was introduced into the autoclave (100 ml), loaded with CO2 (40 atm), and heated to 160 °C for 16 h. After cooling down, the variety is analyzed by GC-MS. Results are shown in Table 4.Table 4. Alkoxycarbonylation reaction: effect of Imidazolium cationReaction Alkyl position Anion Conv. (%) ^sterProduction1 l-Butyl-3-Methyl Cl 100 76.32 l-Ethyl-3-Methyl Cl 99.79 68.553 l-Butyl-3-Methyl Br 100.00 73.974 l-Ethyl-3-Methyl Br 100.00 76.03Example 7 (Effect of the IL mixture)

[0058] 0.064 g of Ru3(CO)i2 was mixed with the corresponding alkyl-imidazolium mixture (BMelmCl, EMelmCl) in a ratio spanning from 0.25 up to 1.5, 1.2 g of 1-Octene, and 20 ± 1 g of methanol in an FTFE vessel. The mixture was introduced into the autoclave (100 ml), loaded with CO2 (40 atm), and heated to 160 °C for 16 h. After cooling down, the variety is analyzed by GC- MS. Results are shown in Table 5.Table 5. Alkoxy carbonylation reaction: effect of Imidazolium cation„ BMelmCl / „ EsterReaction , Conv. (%) , ,%EMelmCl production (%)1 1.25 100 69.152 0.83 100 86.123 0.55 100 76.074 0.28 100 54.22Example 8 (Effect of reaction time)

[0059] 0.064 g of Ru3(CO)i2 was mixed with BMelmCl, 4.54 g, 1.2 g of 1-Octene, and 20 ± 1 g of methanol in an FTFE vessel. The mixture was introduced into the autoclave (100 ml), loaded with CO2 (40 atm), and heated to 160 °C for 6, 12 & 16 h. After cooling down, the variety is analyzed by GC-MS. Results are shown in Table 6.Table 6. Effect of the reaction time on ester productionEster Reaction IL Time (h) Conv (%) . , , ,z. yield (%)1 6 97.87 69.52 BMelmCI 12 99.10 72.53 16 99.27 76.3Example 9 (Effect of reaction temperature)

[0060] 0.064 g of Ru3(CO)i2 was mixed with BMelmCI, 4.54 g (when required), 1.2 g of 1- Octene, and 20 ± 1 g of methanol in an FTFE vessel. The mixture was introduced into the autoclave (100 ml), loaded with CO2 (40 atm), and heated to the indicated temperature for 6 h. After cooling down, the variety is analyzed by GC-MS. Results are shown in Table 7.Table 7. Effect of the reaction temperature on ester production., . EsterReaction Il Temp ( - C) CO"» <%)y|e|d |%)97.87 20.2699.10 58.2899.27 69.599.77 82.19Example 10 (Effect of additional ligand)

[0061] 0.064 g of Ru3(CO)i2 was mixed with the corresponding ligand (0.100 g - 0120 g), BMelmCI, 4.54 g, 1.2 g of 1-Octene, and 20 ± 1 g of methanol in an FTFE vessel. The mixture was introduced into the autoclave (100 ml), loaded with CO2 (40 atm), and heated to 160 °C for 16 h. After cooling down, the variety is analyzed by GC-MS. Results are shown in Table 6.Table 8. Alkoxycarbonylation reaction: effect of additional ligandsEsterIL Ligand Conv. (%) production (%) none bathocuprione 98.65 8.75BMelmCl bathocuprione 81.03 2.7 none Bathophenanthroline 100 2.18BMelmCl Bathophenanthroline 98.44 26.46Example 11 (alcohol source)

[0062] 0.064 g of Ru3(CO)i2 was mixed with the desired IL (3.5 g of l-butyl-3 -methyl imidazolium chloride, or 4.2 g of l-ethyl-3 -methyl imidazolium chloride), 1.2 g of 1-Octene, and 19.3 g of the corresponding alcohol (MeOH or EtOH) in an FTFE vessel. The mixture was introduced into the autoclave (100 ml), loaded with CO2(40 atm), and heated to 160 °C for 16 h. Results are shown in Table 9.Table 9. Alkoxycarbonylation reaction: alcohol source„ , Conv. Ester productionReaction IL Alcohol1 BMelmCl MeOH 100 81.972 EtOH 100 82.53 EMelmCl MeOH 99.90 89.354 EtOH 99.20 91.45Example 12 (Use of industrial olefin-containing stream)

[0063] 0.1923 g of Ru3(CO)i2 was mixed with the corresponding olefin-containing stream (Mix 1 (C9-C16), 4.82 g or Mix 2 (C14-C20), 6.05 g), the desired IL (BMelmCl, 10.46 g or EMelmCl, 8.45 g), and 50 ± 1 g of methanol in an FTFE vessel. The mixture was introduced into the autoclave (300 ml), loaded with CO2 (40 atm), and heated to 160 °C for 16 h. After cooling down, the variety is analyzed by GC-MS. Results are shown in Table 10.Table 10. Alkoxy carbonylation reaction with industrial olefin-containing streamOlefin , , EsterReaction IL Conv. (%) , mixture production (%)1 , Mix l 65.5 32.25BMelmCl2 Mix 2 48.35 30.253 , Mix l 63.25 31.05EMelmCI4 Mix 2 45.35 29.85Example 13 (Uses of bimetallic combination)

[0064] 0.064 g of Ru3(CO)i2 and 0.056 g Fe3(CO)i2 or 0.034 Co2(CO)s was mixed with BMelmCl, 4.54 g, 1.2 g of 1-Octene, and 20 ± 1 g of methanol in an FTFE vessel. The mixture was introduced into the autoclave (100 ml), loaded with CO2 (40 atm), and heated to 160 °C for 16 h. After cooling down, the variety is analyzed by GC-MS. Results are shown in Table 11.Table 11. Alkoxycarbonylation using bimetallic catalyst precursor systems.Reaction Catalyst precursor IL Conv. (%)1 Fe3(CO)1264.96 5.692 Fe3(CO)12 / Ru3(CO)1298.64 18.4BMelmCl3 Co2(CO)846.32 1.854 CO2(CO)8 / RU3(CO)1297.88 16.72Example 14. CO2 Capture followed by Alkoxycarbonylation

[0065] 0.064 g of Ru3(CO)i2 was mixed with 3.5 g of l-butyl-3 -methyl imidazolium chloride and 10 g of MeOH in an FTFE vessel. The mixture was introduced into the autoclave (100 ml), loaded with CO2 (10 atm), and heated to 80 C for 1 h. After this time, the system was heated up to 160 C. Upon reaching the temperature, 1.2 g of 1-Octene, and 10 g of methanol loaded in a high-pressure cylinder previously loaded with CO2 (42 atm) were introduced into the autoclave (100 ml) and reacted for 6 h. After cooling down, the mixture is analyzed by GC-MS, indicating 1- octene conversion of 99 %, ester formation, 85 ± 4 %, olefin isomerization, 7 ± 2 %, octane 6 ± 1Example 15 CO2 Capture followed by Alkoxycarbonylation

[0066] [2-(Di-ter-butylphosphinomethyl)-6-(diethylaminomethyl)pyridine]carbony chloral hydrate ruthenium (II), 0.042 g was mixed with 3.5 g of l-Butyl-3 -Methyl Imidazolium chloride and 10 g of MeOH in an FTFE vessel. The mixture was introduced into the autoclave (100 ml), loaded with CO2 (10 atm), and heated to 80 C for 1 h. After this time, the system was heated up to 160 C. Upon reaching the temperature, 1.2 g of 1 -Octene, and 10 g of methanol loaded in a high-pressure cylinder previously loaded with CO2 (42 atm) were introduced into the autoclave (100 ml) and keep the reaction for 5 h. After cooling down, the mixture is analyzed by GC-MS, indicating 1 -octene conversion of 94 %, ester formation, 7 ± 1 %, olefin isomerization, 78 ± 2 %, and octane 7 ± 1 %.

[0067] The specific embodiments described above have been shown by way of example, and it should be understood that these embodiments may be susceptible to various modifications and alternative forms, and can also be used in any appropriate combination. It should be further understood that the claims are not intended to be limited to the particular forms disclosed, but rather to cover all modifications, equivalents, and alternatives falling within the scope of this disclosure.

Claims

WHAT IS CLAIMED IS:

1. A method of reactive CO2 capture to produce low carbon intensity (CI) diesel fuel, comprising: capturing CO2 from a flue gas using a capture medium; combining the captured CO2 in the capture medium, an alcohol, and an olefin in a reactor; and catalyzing, in the reactor, an alkoxycarbonylation reaction between the CO2, the alcohol, and the olefin using a catalyst to produce the low CI diesel fuel.

2. The method of claim 1, comprising: flowing the flue gas along a CO2 flow path extending from a source of the flue gas and to the reactor; and mixing the flue gas with the capture medium in a CO2 capture vessel positioned along the CO2 flow path such that the capture medium captures CO2 contained within the flue gas to produce a captured CO2 stream and a CCh-lean exhaust gas stream, wherein the captured CO2 stream comprises CO2 in the capture medium.

3. The method of claim 2, comprising: introducing the olefin and the alcohol to the CO2 flow path between the CO2 capture vessel and the reactor such that a mixture of the captured CO2 stream, the olefin, and the alcohol is introduced into the reactor, wherein the reactor contains the catalyst; and flowing, along a product flow path, reactor effluent comprising at least the low CI diesel fuel, unreacted CO2, capture medium, and alcohol from the reactor to a separation system.

4. The method of claim 3, comprising: in the separation system, separating unreacted CO2 and alcohol from the reactor effluent to produce a first recycle stream depleted, relative to the reactor effluent, in the capture medium and the low CI diesel fuel and enriched, relative to the reactor effluent, in the unreacted CO2 and alcohol and a first product stream enriched in the capture medium and the low CI diesel fuel and depleted in the unreacted CO2 and alcohol; andflowing, along a first recycle flow path, the first recycle stream from the separation system to the reactor.

5. The method of claim 4, comprising: in the separation system, separating the capture medium from the low CI diesel fuel to produce a second recycle stream depleted, relative to the first product stream, in the low CI diesel fuel and enriched, relative to the first product stream, in the capture medium and a second product stream depleted, relative to the first product stream, in the capture medium and enriched, relative to the first product stream, in the low CI diesel fuel; and flowing, along a second recycle flow path, the second recycle stream from the separation system to the reactor.

6. The method of claim 1, wherein the capture medium comprises an ionic liquid.

7. The method of claim 6, wherein the ionic liquid comprises a l-butyl-3 -methyl imidazolium (BMelm) cation, l-ethyl-3 -methyl imidazolium (EMelm) cation, l-hexyl-3 -methyl imidazolium (HeMelm) cation, or any combination thereof.

8. The method of claim 1, wherein the alcohol comprises methanol, ethanol, propanol, butanol, or any combination thereof.

9. The method of claim 1, wherein the alcohol comprises renewable ethanol.

10. The method of claim 1, wherein the alcohol consists essentially of renewable ethanol.

11. The method of claim 1, comprising sourcing the olefin from an olefin stream generated in the same refinery or petrochemical plant in which the reactor is located.

12. The method of claim 11, wherein the olefin stream comprises a fluid catalytic cracking (FCC) exhaust gas or a steam cracker waste stream.

13. The method of claim 11, wherein the olefin stream comprises a mixture of olefins having carbon numbers between 9 and 20.

14. The method of claim 11, wherein the olefin stream comprises propylene tetramer, propylene pentamer, or a combination thereof.

15. The method of claim 1, wherein the catalyst comprises a ruthenium, iron, or cobalt- containing catalyst, or any combination thereof.

16. The method of claim 15, wherein the catalyst comprises the formula Fe3(CO)i2, Co2(CO)8, or RU3(CO)I2.

17. The method of claim 1, wherein the flue gas is generated by a process located in the same refinery or petrochemical plant in which the reactor is located.

18. A system for reactive CO2 capture to produce low carbon intensity (CI) diesel fuel, comprising: a CO2 flow path extending from a source of flue gas and to an alkoxy carbonylation reactor; a CO2 capture vessel positioned along the CO2 flow path and configured to receive a capture medium from a capture medium source and to mix the flue gas with the capture medium and thereby allow the capture medium to capture CO2 contained within the flue gas to produce a captured CO2 stream and a CCh-lean exhaust gas stream; one or more injection points configured to introduce an olefin and an alcohol into the CO2 flow path; and the alkoxycarbonylation reactor positioned along the CO2 flow path and configured to receive the captured CO2 in the capture medium, the olefin, and the alcohol, wherein the alkoxycarbonylation reactor comprises a catalyst configured to catalyze an alkoxycarbonylation reaction between the olefin, the alcohol, and the captured CO2 to produce the low CI diesel fuel.

19. The system of claim 18, comprising: a separation system positioned downstream of the alkoxycarbonylation reactor and configured to receive effluent from the alkoxy carbonylation reactor along a product flow path; a first separation stage of the separation system positioned along the product flow path and configured to separate unreacted CO2 and alcohol from the reactor effluent to produce: a first recycle stream depleted, relative to the reactor effluent, in the capture medium and the low CI diesel fuel and enriched, relative to the reactor effluent, in the unreacted CO2 and alcohol; and a first product stream enriched, relative to the reactor effluent, in the capture medium and the low CI diesel fuel and depleted, relative to the reactor effluent, in the unreacted CO2 and alcohol; and a first recycle flow path configured to transmit the first recycle stream from the separation system to the alkoxycarbonylation reactor.

20. The method of claim 19, comprising: a second separation stage of the separation system positioned along the product flow path and configured to receive the first product stream from the first separation stage, and configured to separate the capture medium from the low CI diesel fuel to produce a second recycle stream depleted, relative to the first product stream, in the low CI diesel fuel and enriched, relative to the first product stream, in the capture medium and a second product stream depleted, relative to the first product stream, in the capture medium and enriched, relative to the first product stream, in the low CI diesel fuel; and a second recycle flow path configured to flow the second recycle stream from the separation system to the alkoxy carbonylation reactor.

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