CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority of U.S. Provisional Patent Application No. 62/558,454 filed September 14, 2017, which is hereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

A. Field of the Invention

[0002] The invention generally concerns methods of producing α,β-unsaturated carboxylic acid salts through coupling of an alkene and carbon dioxide. In particular, the invention concerns reacting an alkene and carbon dioxide with a composition that includes an inorganic base and a carboxylation catalyst to produce an α,β-unsaturated carboxylic acid salt.

B. Description of Related Art

[0003] α,β-Unsaturated carboxylic acids (e.g., acrylic acid or methacrylic acid) or salts thereof are commercially produced through a two-step oxidation of propylene process (shown below in Reaction Scheme (1):

O O

^\ + 0 ₂ CATALYST^ ¾ _¾ ^L _H + 0 ₂ CATALYST^ ¾ ^ ₀ Η

(i).

This process requires two reactors and two separate catalysts to oxidize the propylene to acrylic acid, which can be capital intensive and inefficient.

[0004] Cracking processes for the production of ethylene are becoming more popular, owing in part to the abundance of inexpensive shale-based ethane. The shifting trend toward increased ethane cracking is forecast to result in increased propylene prices, and contribute to the cost of propylene-derived α,β-unsaturated carboxylic acid production. In order to remain competitive, α,β-unsaturated carboxylic acid manufacturers must be able to shift production from increasingly expensive propylene to the less expensive ethylene alternative.

[0005] In the ethylene-based production of α,β-unsaturated carboxylic acids, a catalyst is used to couple ethylene and carbon dioxide, resulting in the formation of a metallolactone intermediate as shown in the Reaction Scheme (2) below:

(2)

[0006] The catalyst is represented by M-Ln where M is the catalytically active metal and Ln is one or more ligands. A base is then employed to decompose the metallolactone intermediate into an α,β-unsaturated carboxylic acid or carboxylate (inorganic base salt of the α,β-unsaturated carboxylic acid) and regenerate the catalyst. By way of example, International Patent Application Publication No. WO 2015/173295 to Limbach et al. describes a silica supported transition metal complex for conversion of ethylene to an α,β- unsaturated carboxylic acid. In another example, International Patent Application No. WO 2016180775 to Schaub et al. describes reacting ethylene with CO2 in the presence of transition metal catalyst and sodium tert-butoxide or sodium isopropoxide base to decompose the metallocene, with the alkoxide being consumed during the reaction.

[0007] One of the problems associated with the ethylene route is the need for a regeneration step for the base. When LiI/NEt3 is used as a base system, there is no economic way to regenerating these reagents. When using phenoxide or alkoxide bases, a separate step is required to regenerate the base. The base-regeneration problem has recently been described by Manzini et al. {Catalysis Today, 2017, Vol. 281, part 2, pages 379-386) in which the problem with a separate base deprotonation and regeneration step is employed. Separate base deprotonation and regeneration steps are not commercially scalable because they suffer from inefficient conversion and selectivity rates.

SUMMARY OF THE INVENTION

[0008] A discovery has been made that provides a solution to some of the problems discussed above. The solution is premised on the use of an inorganic base in combination with a protic solvent to provide a population of deprotonated solvent molecules. Without wishing to be bound by theory, it is believed that the inorganic base can deprotonate the protic solvent. The deprotonated solvent can then decompose metallolactone intermediates formed from a C02/alkene/ligand-supported metal catalyst reaction. This leads to the production of an α,β-unsaturated carboxylate product, and regeneration of both the protonated solvent molecule and the ligand-supported metal catalyst. The liberated ligand-supported metal catalyst is then free to re-enter the C02-ethylene coupling step of the catalytic cycle. The protonated solvent is believed to act as a co-catalyst by virtue of its deprotonation, participation in the catalytic cycle, and subsequent protonation/regeneration. The regenerated protonated solvent can be subsequently deprotonated and participate in ensuing metallolactone decomposition steps. The inorganic base is present in the reaction mixture, and can also deprotonate and decompose the metallolactone intermediate. In the cases where the inorganic base is partially soluble or insoluble in the protic solvent, it is believed that the deprotonated solvent is primarily responsible for metallolactone deprotonati on/ decompositi on .

[0009] The process of the present invention provides an elegant and cost-effect process for making α,β-unsaturated carboxylic acid salts (e.g., acrylates). Further, the process can be performed in a "one pot" manner, thereby avoiding the need to isolate and regenerate the inorganic base.

[0010] In a particular aspect of the present invention, methods for producing an α,β- unsaturated carboxylic acid salt are described. A method can include reacting an alkene and carbon dioxide with a composition that can include a carboxylation catalyst and an inorganic base in a protic solvent under reaction conditions suitable to produce an inorganic base salt of an α,β-unsaturated carboxylic acid. In some aspects, the alkene, carbon dioxide, and the metal from the carboxylation catalyst can form a metallolactone. In some embodiments, the metallolactone cam be an intermediate metallolactone and undergoes a subsequent reaction. In some instances, the alkene can be ethylene and the inorganic base salt of the α,β- unsaturated carboxylic acid can be an alkali metal or an alkaline earth metal acrylate, preferably sodium or lithium acrylate. In some embodiments, an inorganic base salt of the protic solvent can be formed in situ from the inorganic base, and the inorganic base salt of the protic solvent reacts with the metallolactone to form the inorganic base salt of an α,β- unsaturated carboxylic acid, the protic solvent, and the carboxylation catalyst. Reaction conditions can include: (a) maintaining the composition at a temperature of 120 °C to 200 °C, preferably 120 °C to 160 °C; (b) an alkene pressure of 0.1 MPa to 5 MPa, preferably 0.5 MPa to 1.5 MPa, or about 1.0 MPa; and (c) a carbon dioxide pressure of 0.1 MPa to 5.0 MPa, preferably 0.1 MPa to 1.0 MPa, or 0.1 MPa to 0.5 MPa. In some embodiments, the composition can include 0.0001 wt.% to 1 wt.% of the catalyst and 0.1 wt.% to 200 wt.% of the inorganic base. In some aspects, the protic solvent can be an alcohol comprising 4 to 35 carbon atoms. In other instances, the alcohol can be one that has a melting point of up to 120 °C. Non-limiting examples of alcohols that can be used in the context of the present invention include Ci to Cio alcohols (e.g., Ci, C ₂ , C ₃ , C ₄ , Cs, C ₆ , d, Cs, C9, C10 substituted alcohols. Non-limiting examples of Ci to Cio alcohols include methanol, ethanol, «-propanol, isopropanol, «-butanol, isobutanol, tert-butanol, cyclohexanol, 2-methyl-2-butanol, 2- pentanol or mixtures thereof. In a preferred instance, the protic solvents can be 2-methyl-2- butanol, 2-pentanol, or mixtures thereof.

[0011] In some aspects, a method for producing an α,β-unsaturated carboxylic acid salt further includes the steps of separating the inorganic base salt of an α,β-unsaturated carboxylic acid from the protic solvent and the carboxylation catalyst, and optionally providing an additional alkene, carbon dioxide, and/or inorganic base to the protic solvent to produce additional α,β-unsaturated carboxylic acid salt. In specific embodiments, the alkene is ethylene, the protic solvent is 1-butanol, and the produced inorganic base salt of the α,β- unsaturated carboxylic acid is an alkali metal or an alkaline earth metal acrylate, preferably sodium or lithium acrylate.

[0012] Non-limiting example of inorganic bases can include an alkali metal or an alkaline earth metal containing base, preferably, an alkali metal or alkaline earth metal carbonate, phosphate, nitrate, or halide, or mixtures thereof. Alkali metal or alkaline earth metal carbonates can include sodium hydroxide, sodium carbonate, sodium bicarbonate, lithium hydroxide, lithium carbonate, lithium bicarbonate, potassium hydroxide, potassium carbonate, potassium bicarbonate, cesium hydroxide, cesium carbonate, cesium bicarbonate, magnesium carbonate, calcium carbonate, or mixtures thereof. The carboxylation catalyst and the inorganic base can each be solubilized in the protic solvent. In some aspects, the inorganic base is at least partially soluble in the protic solvent. In some embodiments, the carboxylation catalyst is not solubilized in the protic solvent and the inorganic base is solubilized in the protic solvent. In some embodiments, the carboxylation catalyst is solubilized in the protic solvent and the inorganic base is not solubilized in the protic solvent. In some aspects, the protic solvent can require heating above room temperature in order to solubilize the catalyst and/or the inorganic base. In some embodiments, the inorganic base can be an aqueous inorganic base solution. In some aspects, the composition is absent the aprotic solvent. In further aspects, the method does not include the aprotic solvent. The aqueous inorganic base solution can be immiscible in the composition. The aqueous inorganic base solution can be dispersed in the composition such that a plurality of droplets of the inorganic base solution are present in the composition. In some instances, the composition does not include a Lewis acid. [0013] The carboxylation catalyst can include at least one transition metal of Columns 4- 10 of the Periodic Table. Non-limiting examples of transition metals include nickel (Ni) or palladium (Pd). In some instances, the carboxylation catalyst includes at least one coordinating ligand. In a preferred embodiment, the coordinating ligand can include at least two coordinating atoms selected from phosphorus (P), nitrogen (N), oxygen (O), sulfur (S), and carbene that coordinate with the transition metal. In some instances, the carboxylation catalyst is or (Ph3P)2Ni(C ₂ H ₄ ), where Cy is cyclohexane.

[0014] In the context of the present invention 20 embodiments are described. Embodiment 1 is a method of producing an α,β-unsaturated carboxylic acid salt, the method comprising reacting an alkene and carbon dioxide with a composition comprising a carboxylation catalyst and an inorganic base in a protic solvent under reaction conditions suitable to produce an inorganic base salt of an α,β-unsaturated carboxylic acid. Embodiment 2 is the method of embodiment 1, wherein the alkene, carbon dioxide, and the metal from the carboxylation catalyst form a metallolactone. Embodiment 3 is the method of embodiment 2, wherein an inorganic base salt of the protic solvent is formed in situ from the inorganic base, and wherein the inorganic base salt of the protic solvent reacts with the metallolactone to form the inorganic base salt of an α,β-unsaturated carboxylic acid, the protic solvent, and the carboxylation catalyst. Embodiment 4 is the method of embodiment 3, further comprising: separating the inorganic base salt of an α,β-unsaturated carboxylic acid from the protic solvent and the carboxylation catalyst; and optionally providing an additional alkene, carbon dioxide, and/or inorganic base to the protic solvent to produce additional α,β-unsaturated carboxylic acid salt. Embodiment 5 is the method of any one of embodiment 1 to 4, wherein the protic solvent is an alcohol. Embodiment 6 is the method of embodiment 5, wherein the alcohol comprises 4 to 35 carbons. Embodiment 7 is the method of any one of embodiments 5 and 6, wherein the alcohol has a melting point of up to 120 °C. Embodiment 8 is the method of embodiment 7, wherein the alcohol is a butanol, a pentanol, a hexanol, or mixtures thereof. Embodiment 9 is the method of embodiment 8, wherein the alcohol is 2-methyl-2- butanol, 2-pentanol or mixtures thereof. Embodiment 10 is the method of any one of embodiments 1 to 9, wherein the inorganic base is at least partially soluble in the protic solvent. Embodiment 11 is the method of any one of embodiments 1 to 10, wherein the inorganic base comprises a carbonate, preferably a alkaline metal carbonate, an alkaline earth metal carbonate, or both. Embodiment 12 is the method of embodiment 11, wherein the alkaline metal carbonate is sodium carbonate, potassium carbonate, cesium carbonate, lithium carbonate, or mixtures thereof. Embodiment 13 is the method of any one of embodiments 1 to 12, wherein the carboxylation catalyst comprises at least one transition metal of Columns 4, 5, 6, 7, 8, 9, or 10 of the Periodic Table. Embodiment 14 is the method of embodiment 13, wherein the carboxylation catalyst comprises at least one transition metal, preferably, nickel (Ni) or palladium (Pd). Embodiment 15 is the method of embodiment 14, wherein the carboxylation catalyst comprises at least one coordinating ligand, preferably a coordinating ligand comprising at least two coordinating atoms selected from nitrogen (N), oxygen (O), sulfur (S), and carbene that coordinate with the transition metal. Embodiment 16 is the method of embodiment 15, wherein the carboxylation catalyst is (Cy ₂ PCH2CH2PCy2)Ni(C2H4C0 ₂ ) or (Cy ₂ PCH2CH2CH2PCy2)Ni(C2H ₄ ). Embodiment 17 is the method of any one of embodiments 1 to 16, wherein the alkene is ethylene and the produced inorganic base salt of an α,β-unsaturated carboxylic acid is an alkali metal or an alkaline earth metal acrylate, preferably sodium or lithium acrylate. Embodiment 18 is the method of any one of embodiments 1 to 17, wherein the composition is absent an aprotic solvent. Embodiment 19 is the method of any one of embodiments 1 to 18, wherein the reaction conditions include: (a) maintaining the composition at a temperature of 120 °C to 200 °C, preferably 120 °C to 160 °C; (b) an alkene pressure of 0.1 MPa to 5 MPa, preferably 0.5 MPa to 1.5 MPa, or about 1.0 MPa; and/or (c) a carbon dioxide pressure of 0.1 MPa to 5 MPa, preferably 0.1 MPa to 1 MPa, or 0.1 MPa to 0.5 MPa. Embodiment 20 is the method of any one of embodiments 1 to 19, wherein the alkene is ethylene, the protic solvent is 1- butanol, and the produced inorganic base salt of the α,β-unsaturated carboxylic acid is an alkali metal or an alkaline earth metal acrylate, preferably sodium or lithium acrylate

[0015] The following includes definitions of various terms and phrases used throughout this specification. [0016] The terms "catalyst" and "carboxylation catalyst" are used interchangeably herein. The phrases "deprotonated solvent," "inorganic base salt of the solvent," and "inorganic base salt of the protic solvent" are used interchangeably herein. "pKa" refers to the negative base- 10 logarithm of the acid dissociation constant (Ka) of a solution.

[0017] An "aliphatic group" is an acyclic or cyclic, saturated or unsaturated carbon group, excluding aromatic compounds. An aliphatic group can include 1 to 50, 2 to 25, or 3 to 10 carbon atoms. A linear aliphatic group does not include tertiary or quaternary carbons. A branched aliphatic group includes at least one tertiary and/or quaternary carbon. A cyclic aliphatic group includes at least one ring in its structure. Polycyclic aliphatic groups can include fused, e.g., decalin, and/or spiro, e.g., spiro[5.5]undecane, polycyclic groups. Non- limiting examples of linear, branched or cyclic, aliphatic group substituents include alkyl, halogen (e.g., fluoride, chloride, bromide, iodide), haloalkyl, haloalkoxy hydroxyl (— OH), alkyoxy (—OR ¹ ), ether (R-O-R), carboxylic acid (RCO2H), ester (RCO2OR), amine (NH or NR), ammonium (N(R)3 ⁺ , NH(R)2 ⁺ , NH ₂ (R)i ⁺ , NH ₃ ⁺ ), amide, nitro, nitrile (CN), acyl (RCO), thiol (— SH), sulfoxides, sulfonates,, phosphine (— PRR"), phosphonium (P(R ⁺ , PH(R ⁺ , PH ₂ (R)2 ⁺ , PH ₃ (R)i ⁺ , PH ₄ ⁺ ), thioether (— S— ), where R and R" is each independently an alkyl group or haloalkyl group.

[0018] An "alkyl group" is a linear or branched, substituted or unsubstituted, saturated hydrocarbon. In the context of the present invention, an alkyl group has 1 to 50, 2 to 30, 3 to 25, or 4 to 20 carbon atoms. Alkyl groups in the context of the present invention include all isomers and all substitution types unless otherwise stated. For example, butyl includes n- butyl, isobutyl, and tert-butyl; pentyl includes n-pentyl, 1-methylbutyl, 2-methylbutyl, 3- methylbutyl, 1-ethylpropyl, and neopentyl. Non-limiting examples of alkyl group substituents include halogen, hydroxyl, alkyoxy, haloalkyl, haloalkoxy, carboxylic acid, ester, amine, amide, nitrile, acyl, thiol, and thioether.

[0019] An "alkene" or "alkenyl" is a linear or branched, unsubstituted or substituted, unsaturated hydrocarbon. In the context of this invention, an alkenyl group has 1 to 50, 2 to 30, 3 to 25, 4 to 20, 2 to 8, or 2 to 4 carbon atoms. When alkyl groups are disclosed in this application, the term "alkyl groups" includes all isomers and all substitution types unless otherwise stated. Non-limiting examples of an alkene group substituents include alkyl, halogen, hydroxyl, alkyoxy, haloalkyl, haloalkoxy, carboxylic acid, ester, amine, amide, nitrile, acyl, thiol and thioether. Non-limiting examples of alkenes are shown in Structure LIV and include ethylene, propene, butylene, and styrene. [0020] An "alkynyl" group refers to a linear or branched monovalent hydrocarbon radical of at least 2 carbon atoms with at least one triple bond. In the context of this invention, the alkenyl group has 1 to 50, 2 to 30, 3 to 25, 4 to 20, or 2 to 4 carbon atoms. The alkynyl radical can be optionally substituted independently with one or more substituents described herein. Non-limiting examples include ethynyl (-C≡CH), propynyl (propargyl, -CH2C≡CH), -C≡C-CH ₃ , and the like.

[0021] An "alkylene" group refers to a saturated divalent hydrocarbon group derived from a straight or branched chain saturated hydrocarbon by the removal of two hydrogen atoms. In the context of this invention, an alkenyl group has 1 to 50, 2 to 30, 3 to 25, 4 to 20, or 1 to 4 carbon atoms. Non-limiting examples of alkylene groups include methylene (-CH2- ), ethylene (-CH2CH2-), isopropylene (-CH(CH ₃ )CH ₂ -), and the like.

[0022] An "aryl group" or an "aromatic group" is a substituted or unsubstituted, mono- or polycyclic hydrocarbon with alternating single and double bonds within each ring structure. Non-limiting examples of aryl group substituents include alkyl, halogen, hydroxyl, alkyoxy, haloalkyl, haloalkoxy, carboxylic acid, ester, amine, amide, nitrile, acyl, thiol and thioether.

[0023] A "heteroatom" refers to unsubstituted or substituted atom that is not carbon unless otherwise specified. Non-limiting examples of heteroatoms are oxygen (O), nitrogen (N), phosphorus (P), or sulfur (S). Non-limiting examples of heteroatoms substituents include hydrogen, aliphatic, alkyl, alkynyl, and alkenyl.

[0024] A "heteroaryl group" or "hetero-aromatic group" is a mono-or polycyclic hydrocarbon with alternating single and double bonds within each ring structure, and at least one atom (heteroatom) within at least one ring is not carbon. Non-limiting examples of heteroaryl group substituents include alkyl, halogen, hydroxyl, alkyoxy, haloalkyl, haloalkoxy, carboxylic acid, ester, amine, amide, nitrile, acyl, thiol and thioether.

[0025] The "heterocyclic" group is a mono-or polycyclic saturated or unsaturated hydrocarbon with at least one atom (heteroatom) within at least one ring is not carbon. Examples of heterocyclic rings include, but are not limited to, pyrrolidinyl, tetrahydrofuranyl, dihydrofuranyl, tetrahydrothienyl, tetrahydropyranyl, dihydropyranyl, tetrahydrothiopyranyl, piperidino, morpholino, thiomorpholino, thioxanyl, piperazinyl, homo-piperazinyl, azetidinyl, oxetanyl, thietanyl, homopiperidinyl, oxepanyl, thiepanyl, oxazepinyl, diazepinyl, thiazepinyl, 2-pyrrolinyl, 3-pyrrolinyl, indolinyl, 2H-pyranyl, 4H-pyranyl, dioxanyl, 1,3- dioxolanyl, pyrazolinyl, dithianyl, dithiolanyl, dihydropyranyl, dihydrothienyl, dihydrofuranyl, pyrazolidinylimidazolinyl, imidazolidinyl, 1,2,3,4-tetrahydro iso-quinolinyl. Some non-limiting examples of a heterocyclic group wherein 2 ring carbon atoms are substituted with oxo (=0) moieties are pyrimidindionyl and 1, 1-dioxo-thiomorpholinyl.

[0026] A "haloalkyl" or "haloalkoxy" refers to an alkyl or alkoxy substituted with one or more halogen atoms. [0027] The terms "catecholate" or "catecholate ligand" refer to ligands that include a phenyl ring. In non-limiting example, two oxygen atoms or nitrogen atoms connected to the phenyl ring at the ring's 1 and 2 positions. The ligand connects to the metal center of the catalyst through the two oxygen atoms: , where R'" and R"" are each independently alkyl, aryl, or form a fused ring with the phenyl ring.

[0028] The terms "about" or "approximately" are defined as being close to as understood by one of ordinary skill in the art. In one non-limiting embodiment, the terms are defined to be within 10%, preferably within 5%, more preferably within 1%, and most preferably within 0.5%.

[0029] The terms "wt.%," "vol.%," or "mol.%" refers to a weight, volume, or molar percentage of a component, respectively, based on the total weight, the total volume, or total moles of a material, that includes the component. In a non-limiting example, 10 grams of component in 100 grams of the material is 10 wt.% of component.

[0030] The term "substantially" and its variations are defined to include ranges within 10%, within 5%, within 1%, or within 0.5%.

[0031] The terms "inhibiting," "reducing," "preventing," "avoiding" or any variation of these terms, when used in the claims and/or the specification includes any measurable decrease or complete inhibition to achieve a desired result.

[0032] The term "effective," as that term is used in the specification and/or claims, means adequate to accomplish a desired, expected, or intended result.

[0033] The use of the words "a" or "an" when used in conjunction with any of the terms "comprising," "including," "containing," or "having" in the claims, or the specification, may mean "one," but it is also consistent with the meaning of "one or more," "at least one," and "one or more than one."

[0034] The words "comprising" (and any form of comprising, such as "comprise" and "comprises"), "having" (and any form of having, such as "have" and "has"), "including" (and any form of including, such as "includes" and "include") or "containing" (and any form of containing, such as "contains" and "contain") are inclusive or open-ended and do not exclude additional, unrecited elements or method steps.

[0035] The methods of the present invention can "comprise," "consist essentially of," or "consist of particular ingredients, components, compositions, etc. disclosed throughout the specification. With respect to the transitional phase "consisting essentially of," in one non- limiting aspect, a basic and novel characteristic of the methods of the present invention are their abilities to efficiently produce α,β-unsaturated carboxylic acids salts from an alkene and carbon dioxide.

[0036] Other objects, features and advantages of the present invention will become apparent from the following figures, detailed description, and examples. It should be understood, however, that the figures, detailed description, and examples, while indicating specific embodiments of the invention, are given by way of illustration only and are not meant to be limiting. Additionally, it is contemplated that changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. In further embodiments, features from specific embodiments may be combined with features from other embodiments. For example, features from one embodiment may be combined with features from any of the other embodiments. In further embodiments, additional features may be added to the specific embodiments described herein. DETAILED DESCRIPTION OF THE INVENTION

[0037] The currently available processes to make α,β-unsaturated carboxylic alkali metal or alkaline-earth metal salts use complex steps, increasingly expensive starting materials, reagents that need regeneration, or combinations thereof. A discovery has been made that provides a solution to some or all of these problems. The solution is premised on using an inorganic base in a protic solvent to at least partially deprotonate the protic solvent in a catalytic cycle for production of α,β-unsaturated carboxylic salts.

[0038] These and other non-limiting aspects of the present invention are discussed in further detail below.

A. Methods of Producing α,β-Unstaturated Carboxylic Acids [0039] Methods of producing α,β-unsaturated carboxylic salts of the present invention can include reacting an alkene and carbon dioxide with a composition that includes a carboxylation catalyst, and an inorganic base in a protic solvent under reaction conditions suitable to produce an inorganic base salt of an α,β-unsaturated carboxylic acid. The inorganic base can be soluble, partially soluble, or insoluble in the protic solvent. Thus, and in certain instances, the inorganic base can be dispersed in the protic solvent thereby creating a bi-phasic system. In instances where the inorganic base is solubilized in the protic solvent, a single-phase system can be formed. The protic solvent temperature can be increased to increase solubility of the inorganic base. The reaction temperature can be maintained from 30 °C to 200 °C, 50 °C to 70 °C, or 30 °C, 35 °C 40 °C, 45 °C, 50 °C, 55 °C, 60 °C, 65 °C, 70 °C, 75 °C, 80 °C, 85 °C, 90 °C, 95 °C, 100 °C, 105 °C, 1 10 °C, 1 15 °C, 120 °C, 125 °C, 130 °C, 135 °C, 140 °C, 145 °C, 150 °C, 155 °C, 160 °C, 165 °C, 170 °C, 175 °C, 180 °C, 190 °C, or any value or range there between. An alkene pressure can range from 0.1 MPa to 5 MPa, 0.5 MPa to 1.5 MPa, or about 1.0 MPa or about 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 MPa, or any value or range there between. A carbon dioxide pressure can range from 0.1 MPa to 5 MPa, 0.1 MPa to 1 MPa, or 0.1 MPa to 0.5 MPa, or about 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 MPa, or any value or range there between. The reaction temperature and pressures can be adjusted to maintain the reaction conditions at temperatures that do not affect the catalyst stability. Without wishing to be bound by theory, it is believed that the protonated solvent acts as a co-catalyst by virtue of its deprotonation, participation in the catalytic cycle, and subsequent protonation/regeneration. Reaction Scheme 3 depicts a catalytic cycle for producing α,β-unsaturated carboxylic salts of the present invention.

ROH +Na ₂ CO ₃ — RONa + NaHCO ₃

H ₂ C-CH ₂

R = alkyl

(3)

[0040] In the above reaction, the inorganic base sodium carbonate can be present in the alcohol solvent (e.g., butanol), and at least a portion of the butanol solvent can be deprotonated by the sodium carbonate base. In the lower reaction cycle, the catalyst M-Ln can couple ethylene to CO2 to give the metallolactone intermediate. The deprotonated solvent can react with the metallolactone intermediate to generate the sodium acrylate product, regenerate the butanol solvent, and regenerate the metal catalyst. The regenerated catalyst can participate in a subsequent ethylene/CCh coupling step. The protonated/regenerated solvent can become available for a subsequent deprotonation and reentry into the catalytic cycle. B. Composition

[0041] The composition can include a carboxylation catalyst, an inorganic base, and a protic solvent. The carboxylation catalyst, inorganic base, or both can be solubilized, or substantially solubilized in the protic solvent. The protic solvent temperature can be increased to increase inorganic base solubility and degree of solvent deprotonation. In some embodiments, a metallic co-reagent like metallic zinc, aluminum, iron, manganese (reducing metals) or an organic reducing agent can be included in the composition. Organic reducing agents can include a benzene compound or substituted benzene groups that include at least one hydroxyl group. Non-limiting examples of organic reducing agents include alkyl or aryl esters of 3,4-dihydroxybenzoic acid, 3,4-dihydroxy-benzaldehyde, 3,4-dihydroxy-benzamide, an alkyl or aryl (3,4-dihydroxyphenyl) ketone, 1,4-dihydroxybenzene (hydroquinone) or a substituted hydroquinone, hindered phenols, pyrogallol, methyl gallate, leuco dyes, or mixtures thereof can be added to facilitate regeneration of the metal of the carboxylation catalyst. 1. Bases

[0042] The inorganic base can be selected by the solubility and/or pKa value. If conjugate bases of polyprotic acids are used, the pKa value for the completely ionized base can be used. By way of example, if a bicarbonate is used the pKa ₂ of 10.3 for the dissociation of HCCb to CCb ⁼ is used instead of the pKai value of 3.6 for the dissociation of H ₂ C0 ₃ to HCCb ^" or the apparent pKa of 6.35.

[0043] The inorganic base can be an alkali metal or an alkaline earth metal containing base, or mixtures thereof. The alkali metal or alkaline earth metal containing base can include a metal carbonate (CCb ⁼ ), a metal bicarbonate (HCCb ), a metal phosphates (Η ₂ Ρ0 ₄ , HP0 ₄ ⁼ , P0 ₄ ^3" ), a metal nitrate (N0 ₂ ), or a metal halide (F , CI , Br , I , etc.), or mixtures thereof. Alkali alkali metals include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and/or cesium (Cs). Alkaline earth metals include beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), and/or barium (Ba). Non-limiting examples of metal carbonates or bicarbonates (pKa = about 10.3) include Li ₂ CCb, LiHC0 ₃ , Na ₂ C0 ₃ , NaHC0 ₃ , Mg(HC0 ₃ ) ₂ , MgC0 ₃ , Ca(HC0 ₃ ) ₂ , CaC0 ₃ , Ba(HC0 ₃ ) ₂ , BaC0 ₃ , and the like. Non-limiting examples of metal phosphates (pKa = about 7.2) include NaH ₂ P0 ₄ , Na ₂ HP0 ₄ , Na ₃ P0 ₄ , KH ₂ P0 ₄ , K ₂ HP0 ₄ , K ₃ P0 ₄ , CsH ₂ P0 ₄ , Cs ₂ HP0 ₄ , Cs ₃ P0 ₄ , Mg ₃ P0 ₄ , Ca ₃ P0 ₄ , Ba ₃ P0 ₄ , and the like. Non-limiting examples of metal nitrates (pKa = 9) include LiN0 ₂ , NaN0 ₂ , Mg(N0 ₂ ) ₂ , Ca(N0 ₂ ) ₂ , Ba(N0 ₂ )2, and the like. Non-limiting examples of metal halides include Lil, Nal, KI, Csl, LiCl, LiBr, LiF, ZnCl ₂ , CaCl ₂ , MgCl ₂ , AlCh, FeCh, FeCh, VCh, or the like. In some embodiments, metal halides (e.g., Lewis acids) are not used.

[0044] In some embodiments, phase transfer compounds can be used to improve the solubility of the inorganic base in the protic solvent. Non-limiting examples of phase transfer agents include NaBF ₄ , NaPFe, NaSbFe, Na(B(C ₆ F ₅ ) ₄ ), Na(B(C ₆ H ₃ (CF ₃ ) ₂ ) ₄ ) (here listed for sodium), quaternary ammonium salts, crown ethers and the like.

2. Protic solvent

[0045] In some aspects, the protic solvent can be an alcohol comprising 4 to 35 carbon atoms. Alcohols can be obtained from commercial sources such as Sigma-Aldrich® (U.S.A.). Non-limiting examples of alcohols include a butanol, tert-butyl alcohol, 2-methyl- 2-butanol, a pentanol, 2-pentanol, a hexanol, 2,5-dimethyl-2,5-hexanediol, a heptanol, triacontanol, or mixtures thereof. In a preferred embodiment, the alcohol is a secondary or tertiary alcohol. In some embodiments, the alcohol can be one that has a melting point of up to 120 °C, or from -89 °C to 120 °C, -50 °C to 100 °C, 0 °C to 80 °C, 25 °C to 50 °C or any value or range there between.

3. Carboxylation Catalyst

[0046] The carboxylation catalyst can be any carboxylation catalyst that promotes the reaction between an alkene and carbon dioxide and can be solubilized in the organic base or solvent of the composition. a. Metals

[0047] The metal carboxylation catalyst can include one or more transition metals from Columns 4 through 12 of the Periodic Table coordinating to one or more ligands. Non- limiting examples of transition metals include nickel (Ni), palladium (Pd), platinum (Pt), chromium (Cr), molybdenum (Mo), tungsten (W), manganese (Mn), iron (Fe), ruthenium (Ru), cobalt (Co), iridium (Ir), and rhodium (Rh). The metals used to prepare the catalyst of the present invention can be provided in various oxidation states (e.g., 0, +1, +2, +3, etc.). The metal carboxylation catalyst can include a ligand L that can be displaced by the alkene. Alternatively, a metal carboxylation catalyst/coordination ligand/alkene complex can be obtained initially by reacting a transition metal source with a coordinating ligand and an alkene to give metal carboxylation catalyst/coordination ligand/alkene complex. The metal carboxylation catalyst can be one or more ligands selected from halides, amines, amides, oxides, phosphides, carboxylates, acetyl acetonate, aryl- or alkyl sulfonates, hydride, CO, olefins, dienes, cycloolefins, nitriles, aromatics and heteroaromatics, ethers, PF ₃ , phospholes, phosphabenzenes, and mono-, di- and polydentate phosphinite, phosphonite, phosphoramidite and phosphite ligands. Non-limiting examples of stabilizing ligands include cycloocta-1,3- diene (COD), bis(cyclooctatetraene), bis(cycloocta-l,3,7-triene), bis(o-tolylphosphito) metal (ethylene), tetrakis (triphenylphosphite) bis(ethylene), 4-butyl-naphthalene-l,2-bisolate, 1- methyl-naphthalene-l,2-bisolate, 4-ethyl catecholate, 3,5-di(butyl)-4-(bromo)catecholate, 4- (propyl)catecholate, halides (e.g., bromides and chlorides). The metal carboxylation catalyst can be prepared by known methods or purchased from a commercial supplier. Useful transition metal sources include commercial standard complexes, for example [M(p- cymene)Cl ₂ ] ₂ , [M(benzene)Cl ₂ ]n, [M(COD)2], [M(CDT)], [M(C ₂ H ₄ ) ₃ ], [MC1 ₂ x H2O], [MC1 ₃ x H2O], [M(acetylacetonate) ₃ ], [M(DMS0)4MC1 ₂ ], where M is the transition metal. In a particular embodiment, nickel(bis(cycloocta-l,5-diene) or bis(triphenylphosphine)(ethylene)nickel can be used as the metal carboxylation catalyst. A non-limiting example of a commercial source of the above mentioned metals or metal complexes is Sigma Aldrich® (U.S. A). b. Coordinating Ligands

[0048] The coordinating ligand can be polydentate, for example, a bidentate ligand. The bidentate ligand coordinates once to the metal center of the metal carboxylation catalyst. The coordination ligand can include 2, 3, 4, 5, 6 or more coordination atoms or carbenes. The coordinating atoms can be different or the same. Non-limiting examples of combinations of at least two different coordinating atoms are (P, P), (P, N), (P, O), (P, S), (P, carbene), (O, S), (N, S), (N, O), (N, carbene), (O, carbene), or (S, carbene). In other aspects, the ligand includes at least two of the same coordinating atoms (e.g., (P, P), (N, N), (O, O), (S, S), or (carbene, carbene). In some instances, the bidentate ligand can include two or more heteroatoms (e.g., N, O, and S) or a heteroatom and a carbene (C:) that together coordinate with the metal in the metal carboxylation catalyst. The ligand can be acyclic or cyclic. In some embodiments, the coordinating ligand can include a phosphorus atom in a non- coordinating position of the ligand. In other embodiments, the coordination ligand does not include a phosphorus atom. An amount of coordinating ligand used with the metal coordination catalyst can be determined by the number of coordinating atoms. In a non- limiting example, a 1 : 1 molar ratio of coordinating ligand to metal carboxylation catalyst can be used for a bidentate ligand. i. (Ν,Ν) Ligands

[0049] In one aspect, the coordinating ligand can include two nitrogen atoms (N,N). Non-limiting examples of ligands that include nitrogen atoms include di-, tri- and polyamines, imines, diimines, pyridine, substituted pyridines, bipyridines, imidazoles, substituted imidazoles, pyrroles, substituted pyrroles, pyrazoles and substituted pyrazoles, or combinations thereof. These compounds can be used together (e.g., two pyridines in one ligand or a diimine) to form a ligand having 2 nitrogen compounds. In a preferred aspect, a bidentate ligand can have a 1,4-diaza- 1,3 -butadiene structure:

where Ri, R2, R3, and R ₄ can each independently be a hydrogen, an alkyl, a branched alkyl, a cycloalkyl, an aryl, a substituted aryl, a substituted heteroatom, a halogen, a heterocyclic or a heteroaryl group, or where Ri and R2, R2 and R3, and/or R3 and R ₄ come together with other atoms to form a cycloalkyl, cycloalkenyl, aryl, heteroaryl, or heterocycle ring. Ri and R ₄ can each independently an alkyl, a branched alkyl, a cycloalkyl, an aryl, or a substituted aryl group. R2 and R3 can come together with other atoms to form a cycloalkyl, cycloalkenyl, aryl, heteroaryl, or heterocycle ring. Ri and R2 can come together to form a heteroaryl or heterocycle ring in combination with R3, and R ₄ can be a hydrogen, an alkyl, a branched alkyl, a cycloalkyl, an aryl, a substituted aryl, a heteroaryl group or coming together to with other atoms to form a heteroaryl or heterocyclic ring. Ri through R ₄ can include from 1 to 50 carbon atoms. Non-limiting examples of Ri through R ₄ groups include hydrogen, methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, octadecyl, octacosyl, nonacosyl, triacontyl, cyclohexyl, cyclopentyl, cycloheptyl, cyclooctyl, cyclodecyl, phenyl, 3-methylphenyl, 4-methylphenyl, 2,6-dimethylphenyl, 2,4,6- trimethylphenyl, 3-ethylphenyl, 4-ethylphenyl, 2,6-diethylphenyl, 2,4,6-triethylphenyl, 3- propylphenyl, 4-propylphenyl, 2,6-dipropylphenyl, 3-isopropylphenyl, 4-isopropylphenyl, 2,6-diisopropylphenyl, 2,4,6-tri-isopropylphenyl, 3-butylphenyl, 4-butylphenyl, 2,6- dibutylphenyl, 2,4,6-tributylphenyl, 3-pentylphenyl, 4-pentylphenyl, 2,6-dipentylphenyl, 2,4,6-tripentylphenyl, 3-hexylphenyl, 4-hexylphenyl, 2,6-dihexylphenyl, 2,4,6- trihexylphenyl, 3-heptylphenyl, 4-heptylphenyl, 2,6-diheptylphenyl, 2,4,6-triheptylphenyl, 3- octylphenyl, 4-octylphenyl, 2,6-dioctylphenyl, 2,4,6-trioctylphenyl, 3-nonylphenyl, 4- nonylphenyl, 2,6-dinonylphenyl, 2,4,6-trinonylphenyl, 3-decylphenyl, 4-decylphenyl, 2,6- didecylphenyl, 2,4,6-tridecylphenyl, 3-undecylphenyl, 4-undecylphenyl, 2,6- diundecylphenyl, 2,4,6-triundecylphenyl, 3-dodecylphenyl, 4-dodecylphenyl, 2,6- didodecylphenyl, 2,4,6-tridodecylphenyl and all isomers of propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl. In one instance, the Ri and R ₄ are substituted phenyl groups and R ₂ and R ₃ are defined as above. Such a coordinating ligand can have the general structure of:

where Rs, R ₆ , R7, Rs, R9, Rio, R11, R12, R13, and R14 are independently H, alkyl, branched alkyl, aryl, substituted aryl, or substituted heteroatom groups. The alkyl or branched alkyl groups can have a carbon number from 1 to 10, preferably 1 to 5, more preferably 1 to 3. In some instances, R5, R ₆ , R7, Rs, R9, Rio, R11, R12, R13, and R14 can be selected from methyl, ethyl, and all isomers of propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl. R5, R9, Rio, and R14 can each independently be methyl (CH ₃ ) or isopropyl ((CH ₃ )2CH) groups, or combinations thereof. In particular aspects, the R2 and R ₃ are methyl and the coordinating ligand can have the following specific structures with their corresponding names:

[l,4-bis{2,5-di(methyl)phenyl}-2-(methyl)-3-(methyl)-l,4-dia zabuta-l,3-diene];

[ 1 ,4-bi s { 2, 5 -di(i sopropyl)phenyl } -2-(methyl)-3 -(methyl)- 1 ,4-diazabuta- 1 , 3 -diene] ;

[l,4-bis{2,3,5-tri(methyl)phenyl}-2-(methyl)-3-(methyl)-l,4- diazabuta-l,3-diene]; or

[ 1 ,4-bisphenyl-2-(methyl)-3 -(methyl)- 1 ,4-diazabuta- 1 ,3 -diene] .

[0050] Non-limiting examples of Ri and R2 joined together with other atoms includes cyclic or aromatic rings that include 4 to 10 atoms, or 5 to 6 atoms (e.g., carbon, oxygen, or sulfur). In a particular instance, Ri and R2 can form a pyridine ring (Structure VII) where R3 and R ₄ are as defined above. In some embodiments, R3 and R ₄ form a pyridine or substituted pyridine ring.

[0051] Suitable coordinating ligands can have the following specific structures with their corresponding names:

[N-cyclohexyl- 1 -(2-{ 5-methyl }pyridinyl)ethanimine] .

N-cyclohexyl-l-(2-pyridinyl)ethanimine.

N-(2,5-diisopropyl)phenyl-l-(2-pyridinyl)ethanimine. Other suitable ligands are:

[0052] In a particular instance, Ri and R2 and R3 and R ₄ can form a bi-pyridyl (e.g., 2,2'- bipyridyl, (Structure VIII)), or substituted bipyridyl type structures. In a particular instance, Ri, R2, R3, and R ₄ can join together with other carbon atoms to form phenanthroline (e.g., Structure IX) or substituted phenanthroline type structures.

[0053] Other suitable (N,N) ligands can include an amine and an imine connected through a carbon bridge as depicted in the general structure (XVIII). (XVIII) where Ri, R2, R3, and R ₄ area defined as above and R15 and Ri6 can each independently be a hydrogen, an alkyl, a branched alkyl, a cycloalkyl, an aryl, a substituted aryl, a heteroatom (e.g., O), a substituted heteroatom (e.g., OR), a halogen, a heterocyclic, or a heteroaryl group, or R ₄ and R15 together with other atoms can form a heterocyclic or heteroaryl ring, or R ₄ and Ri6 together with other atoms can form a heterocyclic or heteroaryl ring, or Ri6 is a chemical bond and R3 and R2 come together with other atoms to form a cyclic or heterocyclic ring. R15 and Ri6 can have 1 to 50 atoms (e.g., carbon atoms, or a mixture of carbon atoms and heteroatoms), 2 to 20 atoms or 3 to atoms. By way of example, the bidentate nitrogen ligand can have the following structures:

where R3, R ₄ , R15, and Ri6 are as defined above, and R17, Ris, R19, and R20 can each independently be H, alkyl, or branched alkyl groups, or R17 and Ris, Ris and R19, or R19 and R20 can come together with other atoms to form cyclic, aryl, heterocyclic, heteroaryl rings, or Ri7, Ris, Ri9, and/or R20 come together with other atoms can form a fused cyclic, aryl, heterocyclic, or heteroaryl ring system, or Ri6 is a chemical bond and R3 and R17 come together with other atoms to form a cyclic or heterocyclic ring. The alkyl or branched alkyl groups can have a carbon number from 1 to 10, preferably 1 to 5, more preferably 1 to 3. In some instances, Ri6 is a chemical bond and R3 and R17 come together to form a substituted quinoline ring system as shown in structure (XX).

(XX) where R ₄ , R15, Ris, R19, and R20 are as previously defined. Other suitable ligands include pyrazole or substituted pyrazole compounds as shown in structure (XXI). where R21, R22, R23, R24, R25, R26, R27, and R28 can each independently be H, alkyl, aryl, or branched alkyl groups, or R21 and R22, R21 and R23, and/or R23 and R24 can come together with other atoms to form cyclic, aryl, heterocyclic, heteroaryl rings, or R21, R22, R23, and/or R24 can come together with other atoms to form a fused ring system. In some instances, R23 can be an electron pair, when R24 is part of an aromatic ring. The alkyl or branched alkyl groups can have a carbon number from 1 to 10, preferably 1 to 5, more preferably 1 to 3.

[0054] Other suitable (N,N) bidentate ligands can have the following generic structure:

(XXII) where R40, R41, R42, R43, R44, and R45 can be each independently H, alkyl, or branched alkyl groups or R40 and R ₄₁ , R41 and R42, R42 and R43, R43 and R44, or R44 and R45 can come together with other atoms to form cyclic, aryl, heterocyclic, heteroaryl rings, or R40, R41, R42, R43, R44, and/or R45 can come together with other atoms to form a fused ring system. The alkyl or branched alkyl groups can have a carbon number from 1 to 10, preferably 1 to 5, more preferably 1 to 3. ii. (N, O) and (N, S) Ligands

[0055] In other instances, the coordinating atoms can be different. For example, the ligand includes at least two different coordinating atoms (e.g., (O, S), (N, S), (N, O), (N, carbene), (O, carbene), (S, carbene). By way of example, a (Ν,Ο) or (N,S) bidentate ligand can have the following generic structure: (XXIII) where Ri, R2, R3, R15, and Ri6 are as previously defined for structure (XIII) and X is oxygen or sulfur. Non-limiting examples of coordinating ligands having these structures are: where Rn, Ris, Ri9, R20, R21, R22, R23, R25, R26, and R27 are as previously defined and R25, R26, and R27 can be H, alkyl, aryl, or branched alkyl groups. It should be understood that while not shown as substituted, the ring structures in (XXVI) can be substituted as defined for structures (XXIV). In some instances, the (N, O) ligand (XXVII), where Ri is a hydrogen and R2 is 2, 4, 6-trimethylbenzene having the structure of: (XXVIII). iii. (O, S), (O, O) and (S,S) Ligands

[0056] Suitable (O, S), (O, O) and (S,S) bidentate ligand can have the following generic structure:

where Y is oxygen or sulfur, X is oxygen or sulfur, R50 and R55 can each independently be a hydrogen, an alkyl, a branched alkyl, a cycloalkyl, an aryl, a substituted aryl, a halogen, a heterocyclic, a heteroaryl group, or an electron pair, R51, R52, R53, and R54 can each independently be a hydrogen, an alkyl, a branched alkyl, a cycloalkyl, an aryl, a substituted aryl, a heteroatom (e.g., O), a substituted heteroatom (e.g., OR), a halogen, a heterocyclic, or a heteroaryl group, or R50 and R51 together with other atoms can form a heterocyclic or heteroaryl ring, or R51 and R53 together with other atoms can form a heterocyclic or heteroaryl ring, or R51 is chemical bond or are each independently chemical bonds and R50 and R51 come together with other atoms to form a heterocyclic ring, or R54 is a chemical bond and R54 through R55 come together with other atoms to form a heterocyclic ring. R50, R51, R52, R53, R54, and R55 can have 1 to 50 atoms (e.g., carbon atoms, or a mixture of carbon atoms and heteroatoms), 2 to 20 atoms or 3 to atoms. Non-limiting examples of specific structures include:

where Rso, Rsi, R52, and R53 are as previously defined, or

where Y and X are (0,0), (S,S), or (0,S) and R53 is as previously defined.

It should be understood that while not shown as substituted, the ring structures (XXX) and (XXXI) can be substituted as defined for structures (XXV) and (XXVII). In a particular instance, R53 in ligand (XXXI) is hydrogen and structures (XXXI) are as follows:

iv. (N, Carbene) Ligands

[0057] Suitable (N, carbene) bidentate coordinating ligands can include carbenes in a nitrogen heterocyclic ring (N, Ν,Ν-carbene) and/or sulfur heterocyclic ring(N, N,S-carbene). A (N, Ν,Ν-carbene carbene) bidentate coordinating ligand can have the following general structure:

where R ₆ o, Rei, R ₆ 2, R ₆₃ , R ₆ 4, R ₆₅ , R ₆ 6, R ₆ 7, and R ₆₈ can each independently be H, alkyl, branched alkyl groups, substituted alkyl, aryl, substituted aryl, alkoxy, heterocyclic, or heteroaryl, and X is N or S, or R ₆ o and Rei, R ₆ 2 and R ₆ 4, R ₆ 4 and R ₆ 7, R ₆ 6 and R ₆₈ , or R ₆ 7 and R ₆₈ , or any combination thereof can come together with other atoms to form cyclic, aryl, heterocyclic, heteroaryl rings, or R ₆ o, Rei, R ₆ 4, R ₆ 7, and/or R ₆₈ can come together to form a fused ring system, or R ₆₈ is an electron pair and R ₆ 7 together with other atoms can form a heterocyclic or heteroaryl ring system, or R ₆₈ is an electron pair and R ₆ o, Rei, R ₆ 4 and/or R ₆ 7 together with other atoms can form a heterocyclic or heteroaryl ring system, and/or R ₆ 2 and R ₆ 4 form a chemical bond or R ₆ 2 R ₆₃ , R ₆ 4, and R ₆₅ form a double bond. The alkyl or branched alkyl groups can have a carbon number from 1 to 10, preferably 1 to 5, more preferably 1 to 3. Non-limiting examples of specific coordinating ligands are:

(XLIII) where R ₆ o, Rei, R ₆₂ , R ₆₃ , and R ₆ 4, are as defined above and R ₆₆ , R ₆ 7, R ₆₈ , and R ₆ 9, can each independently be H, alkyl, branched alkyl, substituted alkyl, aryl, substituted aryl, alkoxy, heterocyclic, or heteroaryl groups, or R ₆₃ and R ₆ 9, R ₆ 6 and R ₆ 7, R ₆ 7 and R ₆₈ , or R ₆₈ and R ₆ 9, can come together with other atoms to form cyclic, aryl, heterocyclic, heteroaryl rings, or R ₆ o, Rei, R ₆₃ , and/or R ₆ 9 can come together to form a fused ring system. In a particular instance, structure (XLII) has the specific structure:

[0058] In some instances, a bidentate carbene ligand is used. By way of example, a bidentate carbene can have the following generic structure:

where X and Y are each independently N, S, O, A is a hydrocarbon linking unit having 1 to 5 carbons, R ₆ o, Rei, R ₆₂ , R ₆₃ , R ₆ 4, R ₆₆ , R ₆ 7, are as defined above for structure (XL), and R70, R71, R72, R73, R74, R75, and R76 can each independently be H, alkyl, branched alkyl groups, substituted alkyl, aryl, substituted aryl, alkoxy, heterocyclic, or heteroaryl, or R ₆ o and Rei, R ₆ 2 and R ₆ 4, R70 and R71, R72 and R74, R74 and R73, or any combination thereof, can come together with other atoms to form cyclic, aryl, heterocyclic, heteroaryl rings, or R ₆ o, Rei, R ₆ 4, R77, and/or R73 can come together to form a fused ring system. The alkyl or branched alkyl groups can have a carbon number from 1 to 10, preferably 1 to 5, more preferably 1 to 3. In a particular instance, structure (XLIV) can have the specific structure:

v. Monodentate Ligands [0059] Monodentate ligands can include one coordinating heteroatom. Two monodentate ligands are typically used to coordinate with metal of the metal carboxylation catalyst as each ligand coordinates once to the metal center. Suitable monodentate ligands have the generic structure:

XR ₈₀ R ₈ iR ₈₂ (XLVI) where X is a nitrogen (N), sulfur (S), or oxygen (O) atoms, and R ₈ oR ₈ iR ₈ 2 can each be independently hydrogen, alkyl, cycloalkyl or aryl. vi. (P,P) Ligands

[0060] Suitable (P,P) bidentate coordinating ligands can include phosphorus. Non- limiting examples of (P,P) ligands for the catalyst can include bis(dicyclohexylphosphino)ethane (dcpe, structure XLVII), 1,3- bis(dicyclohexlphosphino)propane (dcpp, structure XL VIII), 1,2- bis(diphenylphosphino)ethane (dppe, structure XLIX), l,3-bis(diphenylphosphino)propane (dppp, structure L), l,4-bis(diphenylphosphino)butane(dppb, structure LI), which are commercially available various suppliers such as Sigma-Aldrich® (U.S.A.).

[0061] The ligands and metals described above can be reacted with alkenes and carbon dioxide to form a metallocycle catalyst intermediate. By way of example, a nickel metal precursor, ligand XL VII can react with the alkene and CO2 to form metallocycle structure LII ((dcpe)Ni(CH ₂ CH ₂ COO)):

In other instances, a nickel metal precursor, ligand XL VIII can react with an olefin to form olefin complexed material shown as structure LIII ((dcpp)Ni(CH ₂ CH ₂ )), which then can react with C0 ₂ to form a metallocycle similar in structure to structure LII.

C. Alkenes and Carbon Dioxide

[0062] Alkenes used in the context of the present invention can be obtained from various commercial or natural sources or be a by-product of a hydrocarbon process (e.g., hydrocracking, etc.). Suitable alkenes are those of the following structure:

where K ^a , R*, R ^c , and K ^d are each independently hydrogen, Ci-12-alkyl, C2-i2-alkenyl, or K ^a and R* together with the other atoms to which they are bonded are a mono- or di- ethylenically unsaturated, 5- to 8-membered carbocycle, with the proviso that at least one R ^a , R*, R ^c , and K ^d is hydrogen. Non-limiting examples of alkenes include ethene, propene, isobutene, butadiene, piperylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1- nonene, 1-decene, styrene, substituted styrene, or combinations thereof. The alkene to be used in the carboxylation can be in a gaseous or liquid phase under the reaction conditions. In one or more embodiments, the alkene is ethylene (ethene).

[0063] Carbon dioxide used in the present invention can be obtained from various sources. In one non-limiting instance, the carbon dioxide can be obtained from a waste or recycle gas stream (e.g., from a plant on the same site, like for example from ammonia synthesis) or after recovering the carbon dioxide from a gas stream. A benefit of recycling carbon dioxide by using it as a starting material in the process of the invention is that it can reduce the amount of carbon dioxide emitted to the atmosphere (e.g., from a chemical production site). The CO2 stream can be include other gases, preferably inert gases such as helium (He), argon (Ar), or nitrogen (N2), and other inert gases that do not negatively affect the reaction. The carbon dioxide stream can include the alkene. The amount of CO2 in the reactant stream can range from 2 vol.%, 3 vol.%, 4 vol.%, 5 vol.%, 10 vol.%, 15 vol.%, 20 vol.%, 25 vol.%, 30 vol.%, 35 vol.%, 40 vol.%, 45 vol.%, 50 vol.%, 55 vol.%, 60 vol.%, 65 vol.%, 70 vol.%, 75 vol.%, 80 vol.%, 85 vol.%, 90 vol.%, 95 vol.%, 98 vol.% or any range or value there between. The amount of alkene in the reactant stream can range from 2 vol.%, 3 vol.%, 4 vol.%, 5 vol.%, 10 vol.%, 15 vol.%, 20 vol.%, 25 vol.%, 30 vol.%, 35 vol.%, 40 vol.%, 45 vol.%, 50 vol.%, 55 vol.%, 60 vol.%, 65 vol.%, 70 vol.%, 75 vol.%, 80 vol.%, 85 vol.%), 90 vol.%), 95 vol.%), 98 vol.% or any range or value there between. A volume ratio of CO2 to alkene can range from 0.02: 1 to 40: 1. 0.02. In some instances, the reactant feed stream can include 2.5 vol.% CO2 and 95.5 vol.% alkene, 25% vol.% CO2 and 75 vol.% alkene, 50 vol.% CO2 and 50 vol.% alkene, 75 vol.% CO2 and 25 vol.% alkene or 97.5 vol.% CO2 and 2.5 vol.% alkene. In a particular instance, 4 vol.% CO2 and 96 vol.% ethylene, 50 vol.%) CO2 and 50 vol.% ethylene, or 75 vol.%> CO2 and 25 vol.%> ethylene can be used.

EXAMPLES

[0064] The present invention will be described in greater detail by way of specific examples. The following examples are offered for illustrative purposes only, and are not intended to limit the invention in any manner. Those of skill in the art will readily recognize a variety of noncritical parameters which can be changed or modified to yield essentially the same results.

Example 1

(Production of Cesium acrylate)

[0065] In a steel autoclave equipped with a stirring bar (PPh ₃ ) ₄ Pd (16.8 mg), Cy2PCH ₂ CH ₂ PCy2 (7.4 mg, where Cy is cyclohexyl), and Cs2C0 ₃ (185.2 mg) were suspended in 2-methyl-2-butanol (9.6153 g). The reactor was closed and charged first with 1 MPa (10 bar) of ethylene and subsequently pressurized up to 3 MPa (30 bar) with CO2. The reactor was then placed in an oil bath maintained at about 140 °C. After stirring for 19 hours, the heating was turned off and the reactor was allowed to cool to room temperature, after which the reactor was carefully vented. To the contents of the autoclave was added D2O (4 mL) and lithium acetate dehydrate (55.6 mg, LiOAc · 2 H2O as an internal standard). The contents of the reactor were vigorously stirred for 10 minutes to ensure extraction of all salts into the D2O layer. The D2O layer was separated from the organic fraction and submitted for NMR. From the ratio between the signal for the acrylates and the signal for the acetate the amount of produced acrylate was determined. The turnover number (TON) was about 8.87 acrylate per palladium, and the turnover frequency (TOF) was about 0.47 h ^"1 for the reaction.

Example 2

(Production of Cesium acrylate)

[0066] In a steel autoclave equipped with a stirring bar (PPh ₃ ) ₄ Pd (12.6 mg), Cy2PCH2CH ₂ PCy2 (5.7 mg), and Cs2C0 ₃ (285.9 mg) were suspended in 2-methyl-2-butanol (10.6991 g). The reactor was closed and charged first with 1 MPa (10 bar) of ethylene and subsequently pressurized up to 3 MPa (30 bar) with CO2. The reactor was then placed in an oil bath maintained at 120 °C. After stirring for 19 hours, the heating was turned off and the reactor was allowed to cool to room temperature, after which the reactor was carefully vented. To the contents of the autoclave was added D2O (4 mL) and lithium acetate dehydrate (26.7 mg, LiOAc · 2 H2O as an internal standard). The contents of the reactor were vigorously stirred for 10 minutes to ensure extraction of all salts into the D2O layer. The D2O layer was separated from the organic fraction and submitted for NMR. From the ratio between the signal for the acrylates and the signal for the acetate, the amount of produced acrylate was determined. The TON was about 1.40 acrylate per palladium and the TOF was about 0.08 h ^"1 for the reaction.

Example 3

(Production of Potassium acrylate)

[0067] In a steel autoclave equipped with a stirring bar (PPh ₃ )4Pd (18.9 mg), Cy ₂ PCH2CH ₂ PCy2 (9.3 mg), and K ₂ C0 ₃ (2.6723 g) were suspended in 2-pentanol (10.0293 g). The reactor was closed and charged first with 1 MPa (10 bar) of ethylene and subsequently pressurized up to 3 MPa (30 bar) with CO2. The reactor was then placed in an oil bath maintained at 120 °C. After stirring for 18 hours, the heating was turned off and the reactor was allowed to cool to room temperature, after which the reactor was carefully vented. To the contents of the autoclave was added D2O (4 mL) and lithium acetate dehydrate (98.0 mg, LiOAc · 2 H2O as an internal standard). The contents of the reactor were vigorously stirred for 10 minutes to ensure extraction of all salts into the D2O layer. The D2O layer was separated from the organic fraction and submitted for NMR. From the ratio between the signal for the acrylates and the signal for the acetate, the amount of produced acrylate was determined. The TON was about 8.58 acrylate per palladium, and the TOF was about 0.48 h ^"1 for the reaction.