Catalytic carboxy carbonylation of olefins to form anhydrides

Abstract

A transition metal catalyst, such as a palladium-phosphine catalyst, is used for effective carbonylation synthesis of olefins to form anhydrides.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Application No. 63 / 355,407, filed on June 24, 2022, which is incorporated by reference into this application. Background Art

[0003] The processes used to commercially produce organic anhydrides may have several disadvantages, which are generally dependent on the carbon length of the anhydride. The commercial synthesis of lower anhydrides such as acetic anhydride (C2) can be efficiently carried out by high temperature thermal cracking of acetic acid or by high temperature and high pressure carbonylation of acetic acid using a rhodium catalyst and methyl iodide as a cocatalyst. On the other hand, higher (C 3+ ) anhydrides are typically prepared from the corresponding carboxylic acids via stoichiometric use of a dehydrating agent such as acetic anhydride or thionyl chloride. Such processes have several disadvantages. For example, commercial butyric anhydride is typically prepared by reactive distillation of butyric acid and acetic anhydride to produce butyric anhydride and acetic acid. This process produces two equivalents of acetic acid as a byproduct. In addition, butyric acid is typically prepared from propylene via a two-step process of hydroformylation of propylene to butyraldehyde followed by oxidation to butyric acid. Similarly, the use of thionyl chloride as a dehydrating agent produces large amounts of HCl and SO2 waste. Therefore, there is an industrial need for an atom-efficient, cost-effective and safer process for preparing organic anhydrides.

[0004] Carbonylation is a basic and atom-economic functionalization of olefins, which covers a wide range of reactions that produce carboxylic acids, esters, aldehydes, amides, amino acids and other derivatives in many academic and industrial settings. There has been recent interest in the synthesis of esters by reacting olefins with carbon monoxide and alcohols. However, to the best of our knowledge, the synthesis of anhydrides by carbonylation of olefins by reaction with carbon monoxide and carboxylic acids has not been reported, which may be due to the weak nucleophilic nature of carboxylic acids. There are some examples of the production of propionic anhydride catalyzed by ethylene. However, these reactions use harsh conditions and are not suitable for higher anhydrides. Alcohols are good nucleophiles and are easily coupled to metal carbonyl complexes to form esters. In contrast, carboxylic acids are poor nucleophiles, which may explain why anhydrides cannot be prepared by simply extending the esterification conditions and why there are no known reports on the catalytic carbonylation of olefins to anhydrides. Summary of the invention

[0005] A kind of atom efficient technology is described below, and this technology can relate to use transition metal catalyst (such as palladium-phosphine catalyst) to carry out the one-step carbonylation anhydride synthesis of olefin under mild temperature and pressure to form anhydride.In certain embodiments, the selectivity of positive isomer and isomer and any mixture of producing asymmetric positive isomer / isomer can be controlled by changing catalyst structure or reaction conditions.C3 or higher olefin, for example propylene or 1-heptene, can form at least two kinds of anhydride isomers.The ability of the selectivity of controlling required isomer by changing ligand structure or reaction conditions is advantageous for commercial use.In certain embodiments, find that benzoyl halide and other promoter additives enhance catalyst solubility, activity, stability and recyclability.

[0006] One embodiment of the method comprises contacting an ethylenically unsaturated compound with carbon monoxide and a carboxylic acid in the presence of a catalyst system, which can be obtained by combining palladium or a palladium compound with a phosphine ligand, thereby forming an organic anhydride. In general, the method is effective not only for the reaction of a single ethylenically unsaturated compound and a carboxylic acid, but also for the formation of cyclic anhydrides and poly(organic anhydrides) from compounds including ethylenically unsaturated groups and carboxylic acid groups, and from dienes and dicarboxylic acids. DETAILED DESCRIPTION

[0007] A. Definition

[0008] "Alkyl" refers to a branched or unbranched saturated hydrocarbon group of 1 to 24 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl, neopentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, tetradecyl, hexadecyl, eicosyl, tetracosyl, etc. The alkyl group can be cyclic or acyclic. The alkyl group can also be substituted or unsubstituted. For example, the alkyl group can be substituted by one or more groups, including but not limited to the alkyl, cycloalkyl, alkoxy, amino, ether, halide, hydroxyl, nitro, silyl, sulfo-oxo or thiol described herein. "Alkyl" can be C1 alkyl, C1-C2 alkyl, C1-C3 alkyl, C1-C4 alkyl, C1-C5 alkyl, C1-C6 alkyl, C1-C7 alkyl, C1-C8 alkyl, C1-C9 alkyl, C1-C 10 Alkyl, etc., up to and including C1-C 24 Alkyl. "Heteroalkyl" refers to an alkyl group in which one or more of the carbon-bonded hydrogen atoms are replaced with a heteroatom, including but not limited to O, S, or N(R)2, wherein each R may independently be hydrogen or a non-hydrogen substituent.

[0009] "Cycloalkyl" refers to a non-aromatic carbonyl ring consisting of at least three carbon atoms. Examples of cycloalkyl include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, norbornyl, etc. "Heterocycloalkyl" is a non-aromatic carbonyl ring type of a cycloalkyl group, in which at least one of the carbon atoms of the ring is replaced by a heteroatom, such as but not limited to nitrogen, oxygen, sulfur or phosphorus. Representative heterocycloalkyls include, but are not limited to, pyrrolidinyl, pyrazolyl, pyrazolidinyl, imidazolinyl, imidazolidinyl, piperidinyl, piperazinyl, oxazolidinyl, isoxazolidinyl, morpholinyl, thiazolidinyl, isothiazolidinyl and tetrahydrofuranyl. Cycloalkyl and heterocycloalkyl can be substituted or unsubstituted. Cycloalkyl groups and heterocycloalkyl groups can be substituted by one or more groups, including, but not limited to, alkyl, cycloalkyl, alkoxy, amino, ether, halide, hydroxyl, nitro, silyl, sulfo-oxo or thiol.

[0010] "Bicyclic cycloalkyl" or "bicyclic heterocycloalkyl" refers to a compound in which two or more cycloalkyl or heterocycloalkyl groups are fused together. Non-limiting examples of bicyclic cycloalkyl groups include, but are not limited to, (1r, 4r)-bicyclo[2.1.1]hexane, (1s, 4s)-bicyclo[2.2.1]heptane, (1R, 6S)-bicyclo[4.2.0]octane, adamantane, and the like. Non-limiting examples of bicyclic heterocycloalkyl groups include, but are not limited to, any of the foregoing groups in which at least one of the carbon atoms is replaced by a heteroatom such as nitrogen, oxygen, sulfur, or phosphorus.

[0011] "Alkenyl" refers to a hydrocarbon having 2 to 24 carbon atoms, wherein the structural formula contains at least one carbon-carbon double bond. Asymmetric structures such as (A 1 A 2 )C=C(A 3 A 4 ) is intended to include both E and Z isomers. Alkenyl groups may be substituted with one or more groups including alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxyl, ketone, azide, nitro, silyl, sulfo-oxo or thiol, and the like.

[0012] "Cycloalkenyl" refers to a non-aromatic carbonyl ring consisting of at least three carbon atoms and containing at least one carbon-carbon double bond (i.e., C=C). Examples of cycloalkenyl groups include, but are not limited to, cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclopentadienyl, cyclohexenyl, cyclohexadienyl, norbornenyl, etc. The term "heterocycloalkenyl" is a cycloalkenyl group and is included in the meaning of the term "cycloalkenyl" in which at least one of the carbon atoms of the ring is replaced by a heteroatom (such as nitrogen, oxygen, sulfur, or phosphorus). Cycloalkenyl and heterocycloalkenyl groups may be substituted or unsubstituted. Cycloalkenyl groups and heterocycloalkenyl groups may be substituted by one or more groups including alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxyl, ketone, azide, nitro, silyl, sulfo-oxo or thiol, etc.

[0013] "Alkynyl" means a hydrocarbon radical of 2 to 24 carbon atoms, wherein the structural formula contains at least one carbon-carbon triple bond. Alkynyl groups can be unsubstituted or substituted with one or more groups, including alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxyl, ketone, azide, nitro, silyl, sulfo-oxo or thiol, and the like.

[0014] "Cycloalkynyl" refers to a non-aromatic carbonyl ring consisting of at least seven carbon atoms and containing at least one carbon-carbon triple bond. Examples of cycloalkynyl groups include cycloheptynyl, cyclooctynyl, cyclononynyl, etc. The term "heterocycloalkynyl" is such as a cycloalkenyl group, and is included in the meaning of the term "cycloalkynyl", wherein at least one of the carbon atoms of the ring is replaced by a heteroatom, such as but not limited to nitrogen, oxygen, sulfur or phosphorus. Cycloalkynyl and heterocycloalkynyl can be substituted or unsubstituted. Cycloalkynyl groups and heterocycloalkynyl groups can be substituted by one or more groups, and these groups include alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, heteroaryl, aldehyde, amino, carboxylic acid, ester, ether, halide, hydroxyl, ketone, azide, nitro, silyl, sulfo-oxo or thiol, etc.

[0015] "Aryl" refers to a group containing any carbon-based aromatic group, including but not limited to benzene, naphthalene, phenyl, biphenyl, anthracene, etc. Aryl can be substituted or unsubstituted. Aryl groups can be substituted by one or more groups, including but not limited to alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, heteroaryl, aldehyde, ─ NH2, carboxylic acid, ester, ether, halide, hydroxyl, ketone, azide, nitro, silyl, sulfo-oxo or thiol as described herein. In addition, aryl can be a monocyclic structure or contain a polycyclic structure, which is a fused ring structure or connected by one or more bridging groups (such as carbon-carbon bonds). For example, aryl can include biaryl, in which two aryl groups are combined together via a fused ring structure as in naphthalene or connected via one or more carbon-carbon bonds as in biphenyl.

[0016] "Heteroaryl" refers to an aromatic group having at least one heteroatom incorporated into the ring of the aromatic group. Examples of heteroatoms include, but are not limited to, nitrogen, oxygen, sulfur, and phosphorus, with N-oxides, sulfur oxides, and dioxides being permissible heteroatom substitutions. Heteroaryl can be substituted or unsubstituted. Heteroaryl can be substituted by one or more groups including, but not limited to, alkyl, cycloalkyl, alkoxy, amino, ether, halide, hydroxyl, nitro, silyl, sulfo-oxo, or thiol as described herein. Heteroaryl can be a monocyclic or alternatively fused ring system. Heteroaryl groups include, but are not limited to, furanyl, imidazolyl, pyrimidinyl, tetrazolyl, thienyl, pyridinyl, pyrrolyl, N-methylpyrrolyl, quinolyl, isoquinolyl, pyrazolyl, triazolyl, thiazolyl, oxazolyl, isoxazolyl, oxadiazolyl, thiadiazolyl, isothiazolyl, pyridazinyl, pyrazinyl, benzofuranyl, benzodioxazolyl, benzothienyl, indolyl, indazolyl, benzimidazolyl, imidazopyridinyl, pyrazolopyridinyl, and pyrazolopyrimidinyl. Additional non-limiting examples of heteroaryl groups include, but are not limited to, pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, thienyl, pyrazolyl, imidazolyl, benzo[d]oxazolyl, benzo[d]thiazolyl, quinolinyl, quinazolinyl, indazolyl, imidazo[1,2-b]pyridazinyl, imidazo[1,2-a]pyrazinyl, benzo[c][1,2,5]thiadiazolyl, benzo[c][1,2,5]oxadiazolyl, and pyrido[2,3-b]pyrazinyl.

[0017] “Halide” refers to F, Cl, Br or I. “Haloalkyl”, “haloalkenyl” and the like refer to a compound or group including at least one halide substituent at any position.

[0018] "Ferrocenyl" refers to any functional group (substituted or unsubstituted at any position) comprising the following ferrocenyl structure:

[0019]

[0020] "Oxydibenzyl" refers to any functional group (substituted or unsubstituted at any position) including the following structure:

[0021]

[0022] "Quinolinyl" refers to any functional group (substituted or unsubstituted at any position) including the following structure:

[0023]

[0024] "Acridinyl" refers to any functional group (substituted or unsubstituted at any position) including the following structure:

[0025]

[0026] "Dihydroacridinyl" refers to any functional group (substituted or unsubstituted at any position) including the following structure:

[0027]

[0028] "Xanthene" refers to any functional group (substituted or unsubstituted at any position) including the following structure:

[0029]

[0030] "10H-phenoxazinyl" refers to any functional group (substituted or unsubstituted at any position) including the following structure:

[0031]

[0032] "Reactor" means any suitable container that can be used for carrying out the catalytic reaction method. The reactor can be a smaller laboratory scale reactor or a larger commercial scale reactor. Smaller reactors include but are not limited to steel pressure reactors containing glass or TEFLON (PTFE) linings. In other aspects, the reactor can be a Hastelloy autoclave with a suitable volume. In some aspects, the reactor can be equipped with an infrared spectroscopy probe for in-situ monitoring of the reaction mixture.

[0033] "Mole ratio" refers to the number of moles of one substance relative to the number of moles of another substance.

[0034] "Turnover Number" or "TON" refers to the number of moles of reaction product divided by the number of moles of precatalyst or catalyst added to or formed in the reactor.

[0035] "Partial pressure" refers to the pressure of a component gas in the atmosphere of the reaction medium, which is the nominal pressure of that component gas if it occupied the entire volume of the original mixture at the same temperature.

[0036] When the term "about" precedes a numerical value, unless otherwise indicated, that numerical value may vary within ±10%.

[0037] B. Catalytic Carboxyl Carbonylation Method

[0038] The catalytic process generally comprises contacting an ethylenically unsaturated compound with carbon monoxide and a carboxylic acid in the presence of a catalyst system, which can be obtained by combining palladium or a palladium compound with a phosphine ligand, thereby forming an organic anhydride. In addition to the general reaction shown in Scheme 1 below, this process can also be used to form cyclic organic anhydrides and poly(organic anhydrides).

[0039] The catalyst system can usually be obtained by combining palladium or a palladium compound with a phosphine ligand, which produces a catalytic palladium-phosphine complex. The formation of the catalyst system can occur before the reaction or can occur in situ, for example, starting materials and palladium or a palladium compound and a phosphine ligand can be loaded into a reactor. In one aspect, the palladium compound is a palladium (0) or palladium (II) compound. The specific example of the palladium compound includes but is not limited to tris (dibenzylideneacetone) dipalladium (0), palladium chloride (π-cinnamyl) dimer, Pd (OAc) 2, PdCl 2, Pd (PhCN) 2Cl 2, Pd (MeCN) 2Cl 2, Pd (PPh 3) 2Cl 2, Pd (COD) Cl 2 or [Pd (π-allyl) Cl] 2. In another specific aspect, the palladium compound is PdCl2, Pd(PhCN)2Cl2, Pd(MeCN)2Cl2, Pd(PPh3)2Cl2, Pd(COD)Cl2, [Pd(π-allyl)Cl]2 or [Pd(cinnamyl)Cl]2.

[0040] Other reaction conditions will generally vary depending on scale and other parameters. A variety of temperatures can be used. In one aspect, the reaction is carried out at a temperature of at least 50°C, such as 50°C-200°C or 50°C-130°C. In another aspect, the reaction is carried out at a temperature of at least 70°C, such as 70°C-200°C or 70°C-130°C. In another aspect, the reaction is carried out at a temperature of at least 100°C, such as 100°C-130°C.

[0041] The reaction can be carried out under light irradiation. Light of various wavelengths can be used. In one aspect, the reaction is carried out under irradiation from a light source, wherein the light source has a wavelength of at least 300nm, such as 300-500nm or 300-430nm. In another aspect, the reaction is carried out under irradiation from a light source, wherein the light source has a wavelength of at least 350nm, such as 350-500nm or 350-430nm. In another aspect, the reaction is carried out under irradiation from a light source, wherein the light source has a wavelength in the range of 350-390nm.

[0042] The reaction can be carried out at the appropriate time usually, and this depends on multiple factors. However, the reaction product can be monitored to determine when the reaction mixture should be quenched when necessary. Suitable reaction times include for example 3-24 hours, for example 10-15 hours, or longer time when carrying out on a large industrial scale. Generally speaking, the reaction can be continued for any suitable time, as indicated by the method for measuring the reaction process and completion. In addition, the carbonylation reaction can be implemented as a part for batch process or continuous process.

[0043] The atmosphere for carrying out catalytic carboxyl carbonylation comprises carbon monoxide or its source. In one aspect, carbon monoxide can be present in the synthesis gas composition comprising hydrogen. In addition, any suitable carbon monoxide gas source can be used, including the precursor material that can form carbon monoxide in the reactor, for example, under the pressure of raising. The example of the precursor material that can form carbon monoxide in situ comprises carbon dioxide, metal carbonyl compound (metal carbonyls), formic acid derivative and methanol etc. These carbon monoxide sources may be desirable for minimizing any toxicity and transportation problem produced by gaseous carbon monoxide.

[0044] The partial pressure of carbon monoxide in the reactor can vary. In one aspect, the partial pressure of carbon monoxide is at least 1 atmosphere (atm). In other aspects, the partial pressure of carbon monoxide is in the range of about 1 atmosphere (atm) to about 100atm. In other aspects, higher pressure carbon monoxide can be used, for example 10-100atm, such as at least 20atm, at least 30atm and about 40atm of carbon monoxide. In some aspects, carbon monoxide or its source or reactor is substantially free of water, or in some aspects, free of water.

[0045] The catalytic reaction can be carried out neat, or in some aspects in a suitable solvent. In one aspect, the reaction is carried out neat in an atmosphere at least partially comprising carbon monoxide or a source thereof, i.e., the reaction medium consists essentially of, or in some aspects consists of, the ethylenically unsaturated compound, the carboxylic acid, and the catalyst system (optionally including a promoter additive).

[0046] In another aspect, the reaction can be carried out in a solvent. In one aspect, the solvent is aromatic. In other aspects, the solvent is a halogenated solvent, a nitrile solvent or an ether solvent. The non-limiting specific examples of suitable solvents include acetonitrile, chlorobenzene, methylene chloride, ethylene dichloride, trifluorotoluene, perfluorotoluene, tetrachloroethane, tetrahydrofuran, benzonitrile, chlorobenzene, pyridine, dibenzyl ether, xylene, toluene, methyl acetate, methyl propionate, ethyl acetate, propyl acetate, butyl acetate, isobutyl acetate, dimethylformamide and dimethyl sulfoxide.

[0047] In some aspects, the reaction medium may further comprise a promoter additive. In one aspect, the promoter additive is an acid. In some aspects, the acid may be an organic acid. In other aspects, the promoter additive is an acyl electrophilic reagent. Non-limiting examples include trifluoroacetic anhydride or acetic anhydride. In another aspect, the promoter additive is halogenated. In other specific aspects, the promoter additive is an aryl halide or a benzoyl halide.

[0048] Specific non-limiting examples of promoter additives include cinnamyl chloride, tetrabutylammonium chloride (TBACl), tetrabutylammonium bromide (TBABr), tetrabutylammonium iodide (TBAI), p-toluenesulfonic acid (PTSA), benzyl chloride, benzoyl bromide, cesium iodide, methyl iodide, 4-iodobenzenetrifluoride, acyl chlorides, lithium chloride, lithium bromide, lithium iodide, 1-iodooctane, a combination of benzyl chloride and lithium chloride, acetic anhydride, trifluoroacetic acid (TFA), trifluoroacetic anhydride, hydrochloric acid (HCl), HCl in a solvent such as dioxane, benzenesulfonic acid (PhSO3H), methanesulfonic acid (MeSO3H), and any combination thereof.

[0049] 1. Ethylenically unsaturated compounds

[0050] The ethylenically unsaturated substrate can vary. As discussed above, for cyclic organic anhydrides, in addition to the carboxylic acid functional group, a single compound can also have an ethylenically unsaturated group, such as a terminal olefin, which can provide the corresponding organic anhydride. Similarly, the ethylenically unsaturated compound can be a diene, such as a di-terminal olefin, which can react with a dicarboxylic acid such as a di-terminal carboxylic acid to provide the corresponding poly(organic anhydride).

[0051] For other cases where the ethylenically unsaturated compound and the carboxylic acid are separate small molecules, the ethylenically unsaturated compound will typically be a monosubstituted olefin, a disubstituted olefin, or a trisubstituted olefin. In one aspect, the ethylenically unsaturated compound is a terminal olefin.

[0052] In a further aspect, the ethylenically unsaturated compound has formula (I):

[0053]

[0054] Where R 1 and R 2 are independently hydrogen, halide, C1-C 24 Alkyl, C1-C 24 Heteroalkyl, C1-C 24 Alkenyl, C1-C 24 Alkynyl, C1-C 24 Halogenated alkyl, C1-C 24haloalkenyl, cycloalkyl, heterocycloalkyl, bicyclic cycloalkyl, bicyclic heterocycloalkyl, cycloalkenyl, cycloalkynyl, aryl or heteroaryl; or wherein R 1 and R 2 Together they form a ring having 4 to 10 carbon atoms; and wherein the wavy bonds represent any geometric isomers.

[0055] In one aspect, the ethylenically unsaturated compound has the formula (I), R 2 is hydrogen (ie, the ethylenically unsaturated compound is a terminal olefin), and R 1 It is hydrogen, halide, C1-C 24 Alkyl, C1-C 24 In another aspect, the ethylenically unsaturated compound has formula (I), R 2 is hydrogen, and R 1 It is hydrogen, halide, C1-C 20 Alkyl, C1-C 20 In another aspect, the ethylenically unsaturated compound has formula (I), R 2 is hydrogen, and R 1 It is hydrogen, halide, C1-C 18 Alkyl, C1-C 18 In another aspect, the ethylenically unsaturated compound has formula (I), R 2 is hydrogen, and R 1 It is hydrogen, halide, C1-C 16 Alkyl, C1-C 16 In another aspect, the ethylenically unsaturated compound has formula (I), R 2 is hydrogen, and R 1 It is hydrogen, halide, C1-C 14 Alkyl, C1-C 14 In another aspect, the ethylenically unsaturated compound has formula (I), R 2 is hydrogen, and R 1 It is hydrogen, halide, C1-C 12 Alkyl, C1-C 12 In another aspect, the ethylenically unsaturated compound has formula (I), R 2 is hydrogen, and R 1 It is hydrogen, halide, C1-C 10Alkyl, C1-C 10 In another aspect, the ethylenically unsaturated compound has formula (I), R 2 is hydrogen, and R 1 is hydrogen, halide, C1-C8 alkyl, C1-C8 heteroalkyl, cycloalkyl, heterocycloalkyl, bicyclic cycloalkyl or bicyclic heterocycloalkyl. Specific non-limiting examples of suitable ethylenically unsaturated compounds include ethylene, propylene and 1-heptene.

[0056] 2. Carboxylic acid

[0057] The carboxylic acid can be added to the reaction mixture or formed in situ from a variety of suitable precursors. In one aspect, the carboxylic acid has formula (II):

[0058]

[0059] Where R 3 It is C1-C 24 Alkyl, C1-C 24 Alkenyl, C1-C 24 Alkynyl, C1-C 24 Halogenated alkyl, C1-C 24 Halogenated alkenyl, C1-C 24 haloalkynyl, cycloalkyl, heterocycloalkyl, bicyclic cycloalkyl, bicyclic heterocycloalkyl, cycloalkenyl, cycloalkynyl, aryl or heteroaryl.

[0060] In another aspect, the carboxylic acid has the formula (II); wherein R 3 It is C1-C 24 Alkyl, C1-C 24 haloalkyl, cycloalkyl, heterocycloalkyl, bicyclic cycloalkyl, bicyclic heterocycloalkyl, cycloalkenyl, cycloalkynyl, aryl or heteroaryl. In another aspect, the carboxylic acid has formula (II); wherein R 3 It is C1-C 20 Alkyl, C1-C 20 haloalkyl, cycloalkyl, heterocycloalkyl, bicyclic cycloalkyl, bicyclic heterocycloalkyl, cycloalkenyl, cycloalkynyl, aryl or heteroaryl. In another aspect, the carboxylic acid has formula (II); wherein R 3 It is C1-C 18 Alkyl, C1-C 18 haloalkyl, cycloalkyl, heterocycloalkyl, bicyclic cycloalkyl, bicyclic heterocycloalkyl, cycloalkenyl, cycloalkynyl, aryl or heteroaryl. In another aspect, the carboxylic acid has formula (II); wherein R 3 It is C1-C 16 Alkyl, C1-C 16haloalkyl, cycloalkyl, heterocycloalkyl, bicyclic cycloalkyl, bicyclic heterocycloalkyl, cycloalkenyl, cycloalkynyl, aryl or heteroaryl. In another aspect, the carboxylic acid has formula (II); wherein R 3 It is C1-C 14 Alkyl, C1-C 14 haloalkyl, cycloalkyl, heterocycloalkyl, bicyclic cycloalkyl, bicyclic heterocycloalkyl, cycloalkenyl, cycloalkynyl, aryl or heteroaryl. In another aspect, the carboxylic acid has formula (II); wherein R 3 It is C1-C 12 Alkyl, C1-C 12 haloalkyl, cycloalkyl, heterocycloalkyl, bicyclic cycloalkyl, bicyclic heterocycloalkyl, cycloalkenyl, cycloalkynyl, aryl or heteroaryl. In another aspect, the carboxylic acid has formula (II); wherein R 3 It is C1-C 10 Alkyl, C1-C 10 haloalkyl, cycloalkyl, heterocycloalkyl, bicyclic cycloalkyl, bicyclic heterocycloalkyl, cycloalkenyl, cycloalkynyl, aryl or heteroaryl. In another aspect, the carboxylic acid has formula (II); wherein R 3 It is C1-C8 alkyl, C1-C8 haloalkyl, cycloalkyl, heterocycloalkyl, bicyclic cycloalkyl, bicyclic heterocycloalkyl, cycloalkenyl, cycloalkynyl, aryl or heteroaryl.

[0061] In one aspect, the carboxylic acid has only one more carbon atom than the ethylenically unsaturated compound.Symmetric anhydrides can be prepared by such matching of carboxylic acids and ethylenically unsaturated compounds.

[0062] In a specific aspect, the ethylenically unsaturated compound is propylene, the carboxylic acid is isobutyric acid, and the organic anhydride is isobutyric anhydride. The reaction will generally proceed according to Scheme 2 (wherein the co-catalytic additive and solvent are independently optional). The reaction products herein and elsewhere will typically produce the desired organic anhydride and isomers of the organic anhydride, as shown in Scheme 1 below.

[0063] Solution 1.

[0064]

[0065] This particular aspect illustrates the versatility and efficiency of the disclosed catalytic process. For example, Scheme 2 compares the disclosed process with an existing process for making isobutyric anhydride (IBAN), which can be used to make the common polyester precursor 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD).

[0066] Solution 2.

[0067]

[0068] Thus, in one specific industrial aspect of the process, the process may further include cracking the isobutyric anhydride formed by carboxyl carbonylation to produce dimethyl ketene, dimerizing two equivalents of dimethyl ketene to provide 2,2,4,4-tetramethyl-1,3-cyclobutanedione, and hydrogenating 2,2,4,4-tetramethyl-1,3-cyclobutanedione to form 2,2,4,4-tetramethyl-1,3-cyclobutanediol. In a further aspect, the process may further include polymerizing 2,2,4,4-tetramethyl-1,3-cyclobutanediol optionally with one or more comonomers to form a polyester. In a further aspect, the isobutyric acid byproduct generated from dimethyl ketene can be reused in a subsequent carboxyl carbonylation reaction.

[0069] 3. Phosphine ligand

[0070] A variety of phosphine ligands can be used to obtain palladium-phosphine catalysts for carboxyl carbonylation reactions. In one aspect, the phosphine ligand is monodentate or bidentate. In another aspect, the phosphine ligand has formula (III) or (IV):

[0071]

[0072] Where R 4 -R 10 are independently halides, C1-C 24 Alkyl, C2-C 24 Alkenyl, C2-C 24 Alkynyl, C1-C 24 Halogenated alkyl, C2-C 24 Halogenated alkenyl, C2-C 20 haloalkynyl, cycloalkyl, heterocycloalkyl, bicyclic cycloalkyl, bicyclic heterocycloalkyl, cycloalkenyl, cycloalkynyl, aryl, heteroaryl, ferrocenyl, or OR 11 , where R 11 It is a halide, C1-C 24 Alkyl, C2-C 24 Alkenyl, C2-C 24 Alkynyl, C1-C 24 Halogenated alkyl, C2-C 24 Halogenated alkenyl, C2-C 24 haloalkynyl, cycloalkyl, heterocycloalkyl, bicyclic cycloalkyl, bicyclic heterocycloalkyl, cycloalkenyl, cycloalkynyl, aryl, heteroaryl or ferrocenyl; and wherein Q is C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, aryl, heteroaryl, heteroaryl, oxydibenzyl, ferrocenyl, quinolinyl, acridinyl, dihydroacridinyl, xanthenyl or 10H-phenoxazinyl.

[0073] In another aspect, the phosphine ligand has the formula (IV); wherein R 7 -R 10R is independently cycloalkyl, heterocycloalkyl, bicyclic cycloalkyl, bicyclic heterocycloalkyl, cycloalkenyl, cycloalkynyl, aryl, heteroaryl or ferrocenyl; wherein Q is aryl, heteroaryl, heteroaralkyl, oxydibenzyl, ferrocenyl, quinolinyl, acridinyl, dihydroacridinyl, xanthenyl or 10H-phenoxazinyl.

[0074] In another aspect, the phosphine ligand has formula (IV), wherein R 7 -R 10 R is independently aryl, and Q is aryl, heteroaryl, heteroaralkyl, oxydibenzyl, ferrocenyl, quinolinyl, acridinyl, dihydroacridinyl, xanthenyl or 10H-phenoxazinyl.

[0075] In another aspect, the phosphine ligand has formula (V):

[0076]

[0077] Where R 12 -R 15 are independently aryl, C1-C 24 Alkyl, 2-pyridyl or 2-furyl; R 16 -R 21 are independently hydrogen or C1-C 24 alkyl; wherein the broken bond lines represent optional bonds; wherein Y 1 If present it is C(CH3)2, NH, NCH3 or CH2.

[0078] In another aspect, the phosphine ligand has formula (VI):

[0079]

[0080] Where R 22 -R 25 are independently aryl, C1-C 24 alkyl, 2-pyridyl or 2-furyl, and wherein Y 2 It is CH2, C2H4C3H6 or C4H8.

[0081] In another aspect, the phosphine ligand has formula (VII):

[0082]

[0083] Where R 26 -R 28 are independently aryl, C1-C 24 alkyl, 2-pyridyl or 2-furyl.

[0084] In another aspect, the phosphine ligand has formula (VIII):

[0085]

[0086] Where R 29 -R 32 are independently aryl, C1-C 24 alkyl, 2-pyridyl or 2-furyl.

[0087] In another aspect, the phosphine ligand has formula (IX):

[0088]

[0089] Where R 33 , R 34 and R 35 -R 36 (when present) are independently aryl, C1-C 24 alkyl, 2-pyridyl or 2-furyl; wherein Y, if present, is CHCH3, CH2 or CHR 37 , where R 37 It is C1-C 24 Alkyl; wherein the broken bond lines represent optional bonds, i.e. -YPR 35 R 36 is an optional substituent.

[0090] Specific non-limiting examples of phosphine ligands include the following:

[0091]

[0092]

[0093]

[0094] Other specific examples of the phosphine ligand include triphenylphosphine, xphos, trioctylphosphine, triethyl phosphite, (9,9-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphane) (xantphos), 2-chloro-4,4,5,5-tetramethyl-1,3,2-dioxaphospholane, tri-tert-butylphosphine, dppf, triphenylphosphine oxide, tricyclohexylphosphine, trioctylphosphine, diphenylphosphine, rac-BINAP, tri(dimethylamino)phosphine, tri-tert-butylphosphonium tetrafluoroborate, trioctylphosphine oxide, tri(o-tolyl)phosphine, tributylphosphine, triphenylphosphite, tBuXPhos, tri-n-butylphosphine, chlorodiphenylphosphine, 1,3-bis( diphenylphosphino) propane, ethylenebis(diphenylphosphine), di-tert-butylchlorophosphine, 1,4-bis(diphenylphosphino)butane, trimethylphosphine, chlorodiisopropylphosphine, 1,2-bis(dicyclohexylphosphino)ethane, tri(diethylamino)phosphine, 1,2-bis(diphenylphosphino)benzene, tricyclohexylphosphine tetrafluoroborate, diphenylphosphine chloride, trimethyl phosphite, (oxydi-2,1-phenylene)bis(diphenylphosphine), tri(2-furyl)phosphine, triphenylphosphine, diphenylphosphine oxide, 1,2,3,4,5-pentaphenyl-1′-(di-tert-butylphosphino)ferrocene, tributylphosphine, trioctylphosphine oxide, dimethylphenylphosphine, DTBPF, phenylphosphonyl dichloride, chlorodicyclohexylphosphine , p,p-dichlorophenylphosphine, methylphosphonyl dichloride, 1,3,5-triaza-7-phosphaadamantane, me4t-butylxphos, tri(trimethylsilyl)phosphine, tri-n-butylphosphine, diethyl methylphosphite, tributylphosphine oxide, triethylphosphine, triethylphosphine oxide, di-tert-butylphosphite, bis(diphenylphosphino)methane, tri(hydroxymethyl)phosphine, tri(4-methoxyphenyl)phosphine, 1,2-bis(dimethylphosphino)ethane, di-tert-butyl(methyl)phosphonium tetrafluoroborate, 2-(diphenylphosphino)ethylamine, methyldiphenylphosphine, di-tert-butylphosphine, N-XantPhos, tri(p-tolyl)phosphine, trimethylphosphite, tert-butyldichlorophosphine , tri(4-fluorophenyl)phosphine, 2-chloro-1,3,2-dioxaphosphinane-4-one, triphenylphosphine hydrobromide, 5-(di-tert-butylphosphino)-1′,3′,5′-triphenyl-1′H-[1,4′]bipyrazole, tri(2,4,6-trimethylphenyl)phosphine, 4-(diphenylphosphino)styrene, tri(pentafluorophenyl)phosphine, diphenyl-2-pyridylphosphine, 1,3,5,7-tetramethyl l-6-phenyl-2,4,8-trioxa-6-phosphaadamantane, tri(o-methoxyphenyl)phosphine, dicyclohexylphosphine, bis(diethylamino)chlorophosphine, diisopropylphosphoramidite dichloride), tris(4-trifluoromethylphenyl)phosphine, 4-(diphenylphosphino)benzoic acid, di-1-adamantylphosphine, 1,1′-tri(diisopropylphosphino)ferrocene, 1,1'-binaphthyl-2,2'-diyl hydrogenphosphate, 2-(di-tert-butylphosphino)-1-phenylindole, 1,5-bis(diphenylphosphino)pentane, MePhos, 1,1,1-tri(diphenylphosphinomethyl)ethane, di(1-adamantyl)-n-butylphosphine hydride, 2-(diphenylphosphino)benzaldehyde, di-tert-butyl n,n-diisopropylphosphoramidite, (6-aminohexyl)triphenylphosphonium bromide hydrobromide, cis-1,2-bis(diphenylphosphino)ethylene, bis(2-diphenylphosphinoethyl)phenylphosphine, 1,1'-bis(dicyclohexylphosphino)ferrocene, 1, 3-Bis(dicyclohexylphosphino)propane bis(tetrafluoroborate), cyclohexyldiphenylphosphine, dichlorodiethylphosphoramidite, tri(1-pyrrolidinyl)phosphine, tri(2,4,6-trimethoxyphenyl)phosphine, tBuXPhos, diphosphoryl chloride, p-chlorodiphenylphosphine, tBuMePhos, 1,3-bis(dicyclohexylphosphino)propane, 2-(diphenylphosphino)benzoic acid, ethylenebis(diphenylphosphine), dimethylphenylphosphite, chloro(tert-butyl)phenylphosphine, diphenylvinylphosphine, 6,6′-[(3,3′-di-tert-butyl-5,5′-dimethoxy-1,1′- bis(diphenyl-2,2′-diyl)bis(oxy)]bis(dibenzo[d,f][1,3,2]dioxaphosphine), (2-hydroxyphenyl)diphenylphosphine, bis(1-adamantyl)-2-dimethylaminophenylphosphine, tris[3,5-bis(trifluoromethyl)phenyl]phosphine, 2,6-bis(di-tert-butylphosphinomethyl)pyridine, triisopropylphosphine, chlorodiethylphosphine, cyclohexyldichlorophosphine, diethylphosphine, ethyldiphenylphosphinate, dicyclohexyl(4-(N,N-dimethylamino)phenyl)phosphine, 3-methyl-1-phenyl-2-phosphine 1-oxide, bis(1-adamantyl)chlorophosphine, Tris[2-(diphenylphosphino)ethyl]phosphine, 4-chlorophenyl dichlorophosphate, tripropylphosphine, di-tert-butylphosphine oxide, 1,3-bis(di-tert-butylphosphinomethyl)benzene, bis(dicyclohexylphosphino)methane, diphenyl(2-methoxyphenyl)phosphine, 1,2-bis(di-tert-butylphosphinomethyl)benzene, N,N-diisopropylmethylphosphonic acid dichloride, ethyldiphenylphosphine, N,N,N′,N′-tetraisopropyldiaminophosphonic acid methyl ester, bis(dimethylamino)chlorophosphine, di(1-adamantyl)benzylphosphine, tri(4-chlorophenyl)phosphine, diethylphenylphosphine, bis(diphenylphosphino)acetylene, 1,2-Bis(dichlorophosphino)ethane, tri-1-naphthylphosphine, 2-(di-tert-butyl-phosphino)-1-phenyl-1h-pyrrole, 4-(dimethylamino)phenyldiphenylphosphine, allyldiphenylphosphine, o-phenylenephosphoryl chloride, bis(dicyclohexylphosphinophenyl)ether, methyldiphenylphosphine oxide, dicyclohexylphenylphosphine, tetrapropylphosphonium bromide, 2-[2-(dicyclohexylphosphino)phenyl]-N-methylindole, di(o-tolyl)phosphine, 9,9-dimethyl-4,5-bis(di-tert-butylphosphino)xanthene, (6-bromohexyl)triphenylphosphonium bromide, (RS)-1-(2-diphenylphosphino-1-naphthyl)isoquinoline, o-phenylenephosphoryl chloride, trimethylphosphite, dichloroisopropylphosphine, diphenyl( trimethylsilyl)phosphine, bis(2,4,6-trimethylphenyl)phosphine, 1-diphenylphosphino-1′-(di-tert-butylphosphino)ferrocene, 1,2-bis(diphenylphosphino)ethane monoxide, bis(3,5-bis(trifluoromethyl)phenyl)phosphine, (2-bromophenyl)diphenylphosphine, tributylphosphine tetrafluoroborate, tri(3,5-dimethylphenyl)phosphine, tert-butyldiphenylphosphine, 2-(dicyclohexylphosphino)-1-phenyl-1H-pyrrole, 1,6-bis(diphenylphosphino)hexane, trioctylphosphine oxide, 2-(2-(diphenylphosphino)ethyl)pyridine, trans-1,2-bis(diphenylphosphino)ethylene, bis(4-methoxyphenyl)chlorophosphine, tri(4-methoxy-3,5-dimethylphenyl)phosphine phosphine, bis(dimethylphosphino)methane, bis(2,4,6-trimethylphenyl)phosphine chloride, (4-hydroxyphenyl)diphenylphosphine, bis(3,5-bis(trifluoromethyl)phenyl)(2′,6′-bis(dimethylamino)-3,6-dimethoxybiphenyl-2-yl)phosphine, P,P′-(9,9-dimethyl-9H-xanthene-4,5-diyl)bis[N,N,N′,N′-tetraethyl-phosphorodiamidite], (R)-(4,4′,6,6′-tetramethoxybiphenyl-2,2′-diyl)bis(bis-3,5-di-tert-butyl-4-methoxyphenyl)phosphine, diphenyl(p-tolyl)phosphine, (R)-(4,4′,6,6′-tetramethoxybiphenyl-2,2′-diyl)bis( bis(3,5-diphenylmethyl)phosphine), 4-(diethylphosphino)-N,N-dimethylaniline, bis(3,5-dimethylphenyl)chlorophosphine, bis(diethylamino)phenylphosphine, 5,5-dimethyl-1,3,2-dioxaphosphinane-2-one, di-tert-butylphenylphosphine, 2-((di-tert-butylphosphinomethyl)-6-diethylaminomethyl)pyridine, bis(dichlorophosphino)methane, bis(3,5-dimethylphenyl)phosphine, 3-(diphenylphosphino)-1-propylamine, 1,4-bis(dicyclohexylphosphino)butane, chlorodi(o-tolyl)phosphine, methyl diphenylphosphinate, di-tert-butylneopentylphosphonium tetrafluoroborate, 2-(di-tert-butylphosphino)dimethylaminobenzene, bis(3,5-di-tert-butyl-4-methoxyphenyl)chlorophosphine, Me3(OMe)tBuXPhos, ethyldiphenylphosphine oxide, bis(3,5-bis(trifluoromethyl)phenyl)(2′,6′-bis(isopropoxy)-3,6-dimethoxybiphenyl-2-yl)phosphine, (1R,2R)-N,N′-bis[2-(diphenylphosphino)benzyl]cyclohexane-1,2-diamine, bis(4-methylphenyl)chlorophosphine, bis(3,5-dimethyl-4-methoxyphenyl)chlorophosphine, tricyclopentylphosphine, 5-(di-tert-butylphosphino)-1-(naphthalen-1-yl)-1H-pyrazole, bis[2-(diadamantylphosphino)ethyl]amine, isopropyldiphenylphosphine, divinylphenylphosphine, 2-(di-tert-butylphosphino) 1-(2-methoxyphenyl)-1H-pyrrole, 2-(1,1-dimethylpropyl)-6-(diphenylphosphino)pyridine, tricyclopentylphosphine tetrafluoroborate, tetraphenyldiphosphine, 5-(dicyclohexylphosphino)-1′,3′,5′-triphenyl-1′H-[1,4′]bipyrazole, 2′-dicyclohexylphosphino-2,4,6-trimethoxybiphenyl, triisopropylphosphonium tetrafluoroborate, (2-bromophenyl)dicyclohexylphosphine, (1R,2R)-2-(diphenylphosphino)cyclohexylamine, bis(2-methoxyphenyl)phosphine, tri(4-methyl-1-piperazinyl)phosphine, (S)-(4,4′,6,6′-tetramethoxybiphenyl-2,2′-diyl)bis(bis(3,5-di-tert-butyl-4-methoxy) 2-(Dicyclohexylphosphino)benzenesulfonic acid, 2-[bis(3,5-dimethylphenyl)phosphino]benzaldehyde, tert-butylphosphonyl dichloride, 2-[bis(2-methoxyphenyl)phosphino]benzenesulfonic acid, (1R,2R)-2-amino-1-phenylpropyldiphenylphosphine, bis(4-methoxyphenyl)chlorophosphine, isocyanatophosphonyl dichloride, 2-(diphenylphosphino)ethylamine tetrafluoroborate, bis(3,5-di-tert-butyl-4-methoxyphenyl)phosphine, 2-[bis(3,5-di-tert-butyl-4-methoxyphenyl)phosphino]benzaldehyde, 9-[2-(diisopropylphosphino)phenyl]-9H-carbazole, (2-aminoethyl)bis(tetrafluoroborate)diisopropylphosphonium, (S)-1-(diphenylphosphino)ethylamine tetrafluoroborate 1H,1H,2H,2H-perfluorodecyl)phenyl]phenylphosphine, tris(2,4-dimethyl-5-aminosulfonic acid phenyl)phosphine trisodium salt, 2-(dicyclohexylphosphino)-N,N-diisopropyl-1H-indole-1-carboxamide, bis(2-isopropoxyphenyl)chlorophosphine, bis(3,5-dimethyl-4-methoxyphenyl)chlorophosphine, di(1-adamantyl)-(2-triisopropylsilyloxyphenyl)phosphine, 1,1′-bis[bis(dimethylamino)phosphino]ferrocene, tert-butylchloro(methyl)phosphine, diethyl 4-(trifluoromethyl)benzylphosphonate, 2-(diphenylphosphino)-N,N,N-trimethylbenzylammonium trifluoromethanesulfonate, 1-methyl-2-(2-diphenylphosphinophenyl)-1H-benzimidazole, triphenylphosphinimine hemisulfate, 2,2′-bis(diphenylphosphino)-1,1′-biphenyl, tetraisopropylvinylidene diphosphonate, 2-(di-tert-butylphosphino)ethylamine, (R)-1-(diphenylphosphino)-3-methyl-2-butylamine, 3-(diphenylphosphino)propane-1 -ammonium tetrafluoroborate, (3-aminopropyl)di-tert-butylphosphonium bis(tetrafluoroborate), (2-aminoethyl)di-tert-butylphosphonium bis(tetrafluoroborate), P,P-dichloroferrocenylphosphine, N-[2-(diphenylphosphino)benzylidene]cyclohexylamine, 2-(diphenylphosphino)benzaldehyde oxime, 2-(di-p-tolylphosphino)benzaldehyde, bis(2-furyl)phosphine chloride 2′-(di-tert-butylphosphino) 1-(4-(di-tert-butylphosphonium)propane sulfonate, DPBP bidentate phosphine, 4-(triphenylphosphino)butane-1-sulfonate, bis(3,5-di(trifluoromethyl)phenyl)chlorophosphine, [1,3-phenylenebis(methylene)]bis(dicyclopentylphosphine), (9-benzyl-9-fluorenyl)dicyclohexylphosphonium tetrafluoroborate, tert-butyldimethylphosphine borane, tert-butyldicyclohexylphosphine Phosphine, di-tert-butyl methyl phosphine, phenyl bis[4-(3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl)phenyl]phosphine, tris[4-(tridecafluorohexyl)phenyl]phosphine, tert-butyl diisopropyl phosphine, 1,1′-bis(phenylphosphino)ferrocene, ethyl o-methylphosphonothioate, benzyl diphenyl phosphine, dichloromethyl phosphine and 1,1′-bis(phenylphosphinilidene)ferrocene.

[0095] In a specific aspect, the phosphine ligand is bis[(2-diphenylphosphino)phenyl]ether (DPEphos) or (9,9-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphine) (also known as Xantphos).

[0096] C. Examples

[0097] The following examples further illustrate the present disclosure. The scope of the present disclosure and claims is not limited by the scope of the following examples.

[0098] 1. Pre-catalyst

[0099] A range of palladium sources were evaluated under a set of standard conditions to see which palladium sources showed activity for the carbonylation coupling of 1-heptene with octanoic acid to form n-octanoic anhydride or isooctanoic anhydride (Table 1). The reaction was performed using Xantphos in an equimolar amount to palladium and was run at 120°C for 16 hours in acetonitrile solvent at 40 atmospheres of CO pressure. Under these conditions, several palladium sources were found to be active precatalysts for the carboxyl carbonylation reaction; the highest yields were obtained using palladium chloride (π-cinnamyl) dimer [Pd(cinnamyl)Cl]2. This precatalyst was used for subsequent ligand and reaction condition evaluations.

[0100] Table 1

[0101]

[0102]

[0103]

[0104] a Toluene was used as solvent. b 10 mol % of Xantphos was used as a ligand. c The reaction time was 3 hours. d Xantphos-coordinated Buchwald carbazole palladium precatalysts generation 3 and 4. e The stoichiometric ratio of olefin to carboxylic acid is 1:3. f 5 mol % of palladium dimer was used as precatalyst. g Chlorobenzene was used as solvent with the reaction run at 105 °C.

[0105] 2. Carbon monoxide partial pressure, stoichiometry and temperature

[0106] Screening of different CO pressures showed that 40 atm (589 psi) carbon monoxide was an effective pressure (Table 2, entry 3). Lower pressures resulted in reduced yields (entries 1 and 2); however, higher pressures should increase yields (entry 4). The ratio of positive to iso was essentially constant at all screened CO pressures. Evaluation of reagent stoichiometry showed that higher equivalents of carboxylic acid were more effective in producing higher yields of positive anhydride isomers (Table 3, entry 8). Additional analysis of the carboxylic acid mixture recovered from the reaction showed the displacement of isoanhydride isomers to produce symmetrical anhydrides. Correcting this displacement, the regioselectivity of the hydropalladium step does not change when an excess of carboxylic acid is used. However, in the case of excess olefins, high yields of anhydrides were observed, but no significant differences in the ratio of positive to iso were found. In addition, slightly reducing the temperature from 120°C to 105°C will increase the selectivity to positive to iso without significantly affecting the overall yield (Table 4, entry 5). Further reduction of the temperature resulted in decreased yields (Table 4, entries 1-4), while higher temperatures (such as 135°C) reduced the selectivity to anhydride in favor of olefin isomerization (Table 4, entry 8).

[0107] Table 2

[0108]

[0109] a The reaction time was 3 hours.

[0110] Table 3

[0111]

[0112]

[0113] a The reaction time was 3 hours. b Conversion rate based on the recovered limiting reagent. c The reactions were run without solvent.

[0114] Table 4

[0115]

[0116] a The reaction time was 3 hours, 3 equivalents of octanoic acid and 1 equivalent of heptene. b The conversion was calculated based on the recovered 1-heptene. c Use 1 equivalent of octanoic acid and 2 equivalents

[0117] Amount of heptene.

[0118] 3. Solvent

[0119] Most of the screened solvents had better solubility for the initial starting materials compared to acetonitrile (Table 5, entry 1). Halogenated solvents and ether solvents improved the solubility of the precatalyst and ligand (entries 2-8). Other aromatic solvents resulted in reduced anhydride yields (entries 9 and 10). Most solvents had a linear to branched ratio similar to acetonitrile; however, perfluorotoluene (entry 6), tetrachloroethane (entry 7), and DMF (entry 12) all showed a significant increase in selectivity for the n-isomer, albeit with reduced yields. Although significant olefin isomerization was detected, no reaction was observed when DMSO was used as a solvent (entry 13). When the reaction was run without solvent, the anhydride yield was >70% with a n / iso ratio of 6 (entry 14). When octanoic acid was used in solvent amounts, the n / iso ratio of the anhydride was significantly improved due to equilibrium in the displacement of the anhydride with the carboxylic acid (entry 15).

[0120] Table 5

[0121]

[0122]

[0123]

[0124] a The precipitate was soluble in DCM during work-up. b Conversion calculated based on recovered 1-heptene. c The reaction was run without solvent.

[0125] 4. Phosphine ligand

[0126] Various ligand types were screened for catalytic activity in the carbonylation of 1-heptene in acetonitrile solvent (Table 6). Under these conditions, the ligands provided anhydride ranging from trace amounts to over 70% in acetonitrile solvent.

[0127] Table 6

[0128]

[0129] Conditions: (A) 1 equivalent of acid, 2 equivalents of olefin, 120°C. (B) 1 equivalent of olefin, 3 equivalents of acid, 105°C.

[0130]

[0131]

[0132]

[0133]

[0134]

[0135] a Conversion based on the recovered limiting reagent. b 5 mol% of allylpalladium chloride dimer was used as precatalyst. c 10 mol% of ligand was used. d Chlorobenzene was used as solvent. Ad = adamantyl, c Pent = cyclopentyl.

[0136]

[0137] Table 7

[0138]

[0139] a The conditions are the same as those in Table 6.

[0140] 5. Catalytic additives

[0141] Adding chloride additives, such as cinnamyl chloride and tetrabutylammonium chloride (TBACl), provides a slight improvement in the reaction yield (Table 8, entries 2 and 3). When a catalytic amount of p-toluenesulfonic acid (PTSA) is added, a decrease in yield is observed (entry 4). Palladium black and other precipitates are typically observed in the above reaction, and this problem is minimized when benzoyl chloride (BzCl) is added in a catalytic amount (entry 5). Using 5mol% BzCl, the loading of the palladium precatalyst can be further reduced to 1mol% or 0.5mol% (entries 6 and 7). Further changing the ratio of palladium: ligand to include excess ligand also helps to minimize the amount of palladium black formed (entries 8, 9 and 10). At lower catalyst loadings, in the absence of BzCl additive, lower yields are observed (entry 11), and in the absence of BzCl and excess ligand, the reaction stops (entry 12). Changing the equivalents of the BzCl additive does not increase the yield or greatly affect the selectivity of the positive / iso (entries 13 and 14).

[0142] Chloride additives were examined at lower palladium loadings in the presence of excess xantphos, and acyl chlorides and cinnamyl chloride (entries 15 and 16) were found to be superior to simple chloride salts such as TBACl and lithium chloride (entries 17 and 18), although lithium chloride as an additive nearly doubled the n / i ratio. Combinations of BzCl and lithium chloride were tried to improve yield and selectivity; however, there was no improvement over BzCl alone as an additive (entry 19). Other acyl additives, acetic anhydride and trifluoroacetic anhydride (TFAA), produced anhydride in reduced yields, but higher n / i selectivities were observed in the case of acetic anhydride additive (entries 20 and 21). Since BzCl and carboxylic acids are known to readily produce anhydrous HCl, other acid sources were added in catalytic amounts. However, anhydrous HCl in dioxane and other sulfonic acids all produced anhydride in lower yields (entries 22-25). Palladium(II) chloride was an active precatalyst under these conditions, and its activity was greatly enhanced when combined with a catalytic amount of benzoyl chloride (entries 26-27).

[0143] Table 8

[0144]

[0145]

[0146]

[0147] Table 9

[0148]

[0149] entry additive Reaction time Positive yield (%) Yield (%) 1 0 mol% benzoyl chloride 2 22 -- 2 2.5 mol% benzoyl chloride 2 28 -- 3 5.0 mol% benzoyl chloride 2 34 -- 4 7.5 mol% benzoyl chloride 2 30 -- 5 10.0 mol% benzoyl chloride 2 30 -- 6 12.5 mol% benzoyl chloride 2 32 -- 7 5.0 mol% benzoyl chloride 6 25 --

[0150] Reagent concentration: P CO =23.8atm, 0.1M heptene, 0.2M octanoic acid, 0.0025M Pd(cinnamyl)Cl2, 0.005M Xantphos.

[0151] Table 10

[0152]

[0153]

[0154]

[0155] Reagent concentration: P CO =23.8 atm, 0.1 M heptene, 0.2 M octanoic acid, 0.0025 M Pd(OAc)2 / Pd(cinnamyl)Cl2 / PdI2, 0.005 M Xantphos.

[0156] a P CO =11.9atm

[0157] Table 11

[0158]

[0159]

[0160] Reagent concentration: P CO =11.9 atm, 0.1 M heptene, 0.2 M octanoic acid, 0.0025 M Pd(OAc)2 / [Pd(cinnamyl)Cl]2, 0.005 M Xantphos.

[0161] a P CO =5.95atm

[0162] Table 12

[0163]

[0164]

[0165]

[0166] 6. Propylene reaction

[0167] Propylene was studied as an olefin to produce symmetric C4 anhydrides with butyric acid and asymmetric C4:C8 anhydrides with octanoic acid. The vast majority of the anhydride products were symmetric products corresponding to the acids present; C8:C8 for the propylene and octanoic acid runs, and C4:C4 for the propylene butyric acid runs (Table 13).

[0168] Table 13

[0169]

[0170] Cat / Lig acid C4 anhydride C4:C8 anhydride C8 Anhydride C4 anhydride normal / iso ratio <![CDATA[Pd(OAc)2 / xant]]> 0.1M Caprylic Acid 0.015M 0.0008M 0.049M 2.5 <![CDATA[Pd(OAc)2 / xant]]> 0.15M Caprylic Acid 0.030M 0.0018M 0.078M 3.3 <![CDATA[Pd(OAc)2 / xant]]> 0.2M Caprylic Acid 0.020M 0.0011M 0.097M 3.4 <![CDATA[Pd(OAc)2 / xant]]> 0.1M Butyric Acid 0.061M -- -- 9.4 <![CDATA[Pd(OAc)2 / xant]]> 0.15M Butyric Acid 0.068M -- -- 13.6 <![CDATA[Pd(OAc)2 / xant]]> 0.2M Butyric Acid 0.113M -- -- 17.9

[0171] Reagent concentration: P CO =175psig, P C3H6 =50psig, 0.0025M Pd(OAc)2, 0.005M Xantphos.

[0172] 7. Propylene reaction at lower pressure

[0173] Propylene was examined at lower CO and propylene pressures and a range of temperatures. At 120°C, 25 psig propylene and 50 psig CO, the anhydride yield was low due to the formation of large amounts of heptene (which was rapidly isomerized to internal olefins), thereby trapping most of the octanoic acid in an inactive form. Lowering the temperature to 105°C and 90°C to suppress the isomerization of 1-heptene resulted in an increase in anhydride yield at lower temperatures. The major products were symmetric C8 acid dehydration condensation products, containing small amounts of symmetric C4 anhydrides (linear and branched), and almost no asymmetric C4:C8 products.

[0174] Table 14

[0175]

[0176]

[0177] Reagent concentration: P CO =3.4atm, P C3H6 =0.7-1.7atm, 0.0025M Pd(OAc)2, 0.005MXantphos.

[0178] a 0.2 mol% Rh was added.

[0179] b 2.0 mol% Rh was added.

[0180] 8. Propylene reaction at higher pressure

[0181] The following standard conditions were first examined with n-butyric acid: 0.5 mol % [Pd(cinnamyl)Cl]2, 2 mol % PPh3 and 5 mol % benzoyl chloride, under 40 atm CO and propylene (p CO =31.2atm, p 丙烯=8.8atm) in DCM solvent. Under these conditions, using 1.33M n-butyric acid, a mixture of anhydrides with a concentration of 0.48M was obtained (Table 15; entry 1). The reaction produced almost equal amounts of branched and linear products. Running the reaction for 22 hours instead of 3 hours formed significantly more isobutyric acid and isobutyric anhydride by post-catalytic scrambling of the acid (Table 15; entry 2). Changing the additive from benzoyl chloride to hydrogen chloride did not increase the reaction yield, but did reduce the branching selectivity (Table 15; entry 3). We tested the reactivity of xantphos and Dtbpx (Table 15; entries 4 and 6) in the presence of benzoyl chloride. Changing the additive to HCl·Et2O slightly increased the linear selectivity of xantphos, but did not increase the linear selectivity of the Dtbpx ligand (Table 15; entries 5 and 7). Reducing the pressure to 20atm significantly reduced the yield (Table 15; entry 8).

[0182]

[0183] Table 15

[0184]

[0185] Reaction conditions: [Pd(cinnamyl)Cl]2 (0.5 mol%), PPh3 (2 mol%), butyric acid (1.5 mmol, 1.33 M), CO / propylene (40 atm) [p 丙烯 =8.8atm,p CO =31.2 atm], 105 °C, 5 mol% benzoyl chloride, 3 h. Using HMDSO as an internal standard, the quantitative 13 C NMR calculates molar concentration. TON = (n-butyric anhydride + mixed anhydride + isobutyric anhydride) / millimole of catalyst. Anhydride L / B = ((2*n-butyric anhydride) + mixed anhydride) / (mixed anhydride + (2*isobutyric anhydride)), and total L / B = ((2*n-butyric anhydride) + mixed anhydride + linear acid) / (mixed anhydride + (2*isobutyric anhydride) + isobutyric acid).

[0186] Reactivity with isobutyric acid was also explored, with standard reaction conditions producing high branching selectivity with moderate TON (Table 16; entry 1). Lower branching selectivity was observed at longer reaction times (Table 16; entry 2). Using xantphos, both high activity and branching selectivity (TON = 104) were observed (Table 16; entry 3). However, when Dtbpx was used for the reaction, the concentration of the combined anhydride was only 0.75 M (Table 16; entry 4), while when xantphos was used for the reaction, the concentration of the combined anhydride was 1.37 M. The increased steric hindrance of the ligand favors the formation of linear products. Reducing the reaction pressure improves the reaction efficiency (Table 16; entry 5).

[0187]

[0188] Table 16

[0189]

[0190] Reaction conditions: [Pd(cinnamyl)Cl]2 (0.5 mol%), ligand (2 mol%), isobutyric acid (1.5 mmol, 1.3 M), CO / propylene (40 atm) [p 丙烯 =8.8atm,p CO =31.2 atm], 105 °C, 5 mol% benzoyl chloride, 3 h. Using HMDSO as an internal standard, the quantitative 13 C NMR calculates molar concentration. TON = (n-butyric anhydride + mixed anhydride + isobutyric anhydride) / millimole of catalyst. Anhydride L / B = ((2*n-butyric anhydride) + mixed anhydride) / (mixed anhydride + (2*isobutyric anhydride)), and total L / B = ((2*n-butyric anhydride) + mixed anhydride + linear acid) / (mixed anhydride + (2*isobutyric anhydride) + isobutyric acid).

[0191] 9. Changes in starting substrate

[0192] Catalytic reactions can be carried out on various types of substrates as shown below.

[0193]

[0194] a 1 mol% Pd dimer, 4 mol% Xantphos. b PhCl as solvent.

[0195] 10. Photochemical carbonylation anhydride synthesis

[0196] The reaction was also carried out using light irradiation. Starting from a change in standard hydrocarbon oxycarbonylation conditions using 0.5 mol% [Pd (cinnamyl) Cl] 2 as a precatalyst, 2 mol% of a Xantphos ligand and 5 mol% of benzoyl chloride as an additive, a combined anhydride yield of 79% was obtained under irradiation from a 370 nm LED at 10 atm of CO, with a normal / iso ratio of 16:1 observed, starting from 1-heptene and 3 equivalents of octanoic acid (entry 1). Under these conditions, a large amount of isoacids were also formed. The use of octanoic acid as a limiting reagent prevented this post-catalytic isomerization, while the total yield of anhydrides did not change (entry 2). The use of longer wavelength LEDs (427 nm and 390 nm) resulted in a slight decrease in yield (entries 3 and 4). The benzoyl chloride additive is not necessary for the conduct of the carbonylation reaction because disproportionation of palladium dimers may occur under irradiation (entry 5). Lower yields were observed at lower pressure (1.1 atm CO, entry 6) and shorter reaction time (3 h, entry 7).

[0197] Simple palladium precatalyst salts without chloride ligands failed to provide the desired anhydride products, although it is possible that no active palladium(0) catalyst was formed under these conditions (entries 8 and 9). Other bidentate phosphine ligands with promising results under thermal conditions produced anhydride products in minor yields under photochemical conditions (entries 10–13).

[0198] Table 17

[0199]

[0200]

[0201] a HMDSO was used as an internal standard and quantitative 13 Yield determined by C NMR. b 2:1 olefin:acid stoichiometry.

[0202] 11. Exemplary intermittent catalytic process (I)

[0203] In an argon-filled glove box, a 2 mL GC vial was charged with a magnetic stir bar, cinnamylpalladium chloride dimer (6.5 mg, 2.5 mol%, 12.5 μmol), xantphos (14.5 mg, 5 mol%, 25 μmol), acetonitrile (1 mL, 0.50 M), octanoic acid (0.24 mL, 3 eq, 1.50 mmol), and 1-heptene (70 μL, 1 eq, 0.50 mmol). The vial was capped with a pre-cut septum and loaded into a Parr reactor where any other reactions were performed under the same pressure and temperature conditions. The reactor was sealed, removed from the glove box, pressurized with carbon monoxide (purged 3 times at 10 atm and then pressurized to 40 atm), placed in a preheated silicone oil bath, and stirred at 105 °C for 3 h. Carbon monoxide is toxic, and all manipulations involving CO should be performed in a well-ventilated and properly functioning fume hood. A personal CO detector (Draeger Pac 6500 series) was used to monitor the atmosphere during these operations. The reactor was then removed from the oil bath, allowed to cool to room temperature, and depressurized in a fume hood. A stock solution of tridecane (3 mL, 5.6 mM in DCM) was added to the reaction mixture as an internal standard. The solution was filtered through a 0.45 μm PTFE syringe filter into a 20 mL scintillation vial and quantified by GC or NMR analysis.

[0204] GC spectra were obtained using a Shimadzu GC-2010 gas chromatograph with a Shimadzu AOC-20s autosampler and a Shimadzu SHRXI-5MS GC column. GC data were obtained using the following method: initial temperature 30.0°C, ramped up to 50.0°C at 5.0°C / min, then ramped up to 250.0°C at 15.0°C / min, and held for 2.0 min. GC yields were supported by comparison with commercially available or independently synthesized products via calibration curves.

[0205] Alternatively, the mixture was concentrated under reduced pressure and then diluted with CDCl3 (1 mL), hexamethyldisiloxane (HMDSO, 15 μL) was added as an internal standard, and the mixture was analyzed by NMR. Proton and carbon magnetic resonance spectra ( 1 H NMR and 13 C NMR) recorded with a CryoQNP probe ( 1 H NMR at 600 MHz, and 13 C at 151 MHz) spectrometer on a Bruker Neo 600 with HMDSO as the internal standard ( 1 H NMR: HMDSO in CDCl3, 0.07 ppm; 13C NMR: HMDSO in CDCl3, 1.97 ppm). Quantitative 13 C NMR analysis.

[0206] 12. Exemplary Batch Catalytic Process (II)

[0207] All samples were prepared using anhydrous solvents in a glove box under a nitrogen atmosphere. About 2 mL of a prepared solution including precursors (1-heptene (0.1 M, 28.2 μL), octanoic acid (0.2 M, 63.4 μL) and a catalyst complex (2:1 L:Pd, 2.5 mM [Pd], 5.0 mM ligand)) was added to a small glass bottle equipped with a magnetic stirrer, a septum to prevent splashing, and a needle that allows the liquid phase to be exposed to CO when placed in a stainless steel autoclave pressurized by CO. The autoclave was sealed and removed from the glove box, and then connected to a gas supply manifold for purging nitrogen and filling with propylene (if necessary) and carbon monoxide (purged 3 times at 10 atm, then filled to the reaction pressure). After purging the manifold CO, the autoclave was sealed and disconnected from the manifold, and then the autoclave was placed in an oil bath and stirred at the reaction temperature for 2 hours. After the reaction, the autoclave was cooled and depressurized, and a sample of the reaction mixture was taken out for GC analysis (900 μL solvent+1.8 mM tridecane internal standard and 100 μL of reaction mixture).

[0208] 13. Exemplary batch catalytic process (III)

[0209] In a nitrogen-filled glove box, a 2 mL GC vial was charged with a magnetic stir bar, cinnamyl palladium chloride dimer (3.8 mg, 0.5 mol%, 0.0075 mmol), ligand (2 mol%, 0.03 mmol), a mixture of deuterated and protonated dichloromethane (1 mL), butyric acid (0.116 mL, 1.50 mmol) or isobutyric acid (0.136 mL, 1.50 mmol) and benzoyl chloride (8.71 μL, 5%, 0.075 mmol). The vial was capped with a septum and punctured 10 times before loading into the Hel-cat reactor. The reactor was sealed, removed from the glove box, and pressurized with carbon monoxide / propylene (78% / 22%) (purged 3 times at 10 atm and then pressurized to the desired pressure). The reactor was heated to 105°C and stirred for the desired hours. Carbon monoxide is toxic, and all manipulations involving CO must be performed in a well-ventilated and functioning fume hood. A personal CO detector (Draeger Pac 6500 series) was used to monitor the atmosphere during these manipulations. The reactor was then allowed to cool to room temperature and depressurized slowly in the fume hood.

[0210] Hexamethyldisiloxane (HMDSO, 15 μL) was added as an internal standard, transferred to an NMR tube (if necessary, filtered through a PTFE syringe filter) and quantified by NMR analysis. 13 C NMR) with CryoQNP probe ( 13 C at 151 MHz) spectrometer on a Bruker Neo 600 with HMDSO as internal standard ( 13 C NMR: recorded in HMDSO in CD2Cl2, 1.97 ppm. Quantitative 13 CNMR analysis.

[0211] 14. Exemplary intermittent photocatalytic process

[0212] In an argon-filled glove box, an Ace Glass pressure tube was charged with cinnamyl palladium chloride dimer (1.3 mg, 0.5 mol%, 2.5 μmol), xantphos (5.8 mg, 2 mol%, 10 μmol), DCM (1 mL, 0.50 M), octanoic acid (0.24 mL, 3 eq., 1.50 mmol) and 1-heptene (70 μL, 1 eq., 0.50 mmol). The vessel was sealed with a Swagelok connector cap and removed from the glove box. In a fume hood with a closed sash, the tube was pressurized to 5 atm CO, purged 3 times with CO to replace argon, set to 10 atm, and stirred for 18 hours under 370 nm irradiation (Kessil PR160-370). The tube was then depressurized and the reaction mixture was diluted with dichloromethane, transferred to a 20 mL scintillation vial, concentrated under reduced pressure, and prepared for NMR analysis in CDCl3 with HMDSO as an internal standard.

[0213] The features and advantages of the present disclosure are apparent from the detailed description, and the claims cover all such features and advantages. A variety of variations will occur to those skilled in the art, and any variations equivalent to those described in the present disclosure fall within the scope of the present disclosure. It will be appreciated by those skilled in the art that the concepts upon which the present disclosure is based can be used as the basis for designing other methods and systems for achieving the multiple purposes of the present disclosure. Therefore, the claims should not be considered to be limited by the description or examples.

Claims

1. A method for preparing an organic anhydride, which comprises contacting an ethylenically unsaturated compound with carbon monoxide and a carboxylic acid in the presence of a catalyst system obtainable by combining palladium or a palladium compound with a phosphine ligand.

2. The method of claim 1, wherein the ethylenically unsaturated compound is a monosubstituted olefin, a disubstituted olefin, or a trisubstituted olefin.

3. The method of claim 1, wherein the ethylenically unsaturated compound is a terminal olefin.

4. The method of claim 1, wherein the ethylenically unsaturated compound has formula (I): Where R 1 and R 2 are independently hydrogen, halide, C1-C 24 Alkyl, C1-C 24 Heteroalkyl, C1-C 24 Alkenyl, C1-C 24 Alkynyl, C1-C 24 Halogenated alkyl, C1-C 24 haloalkenyl, cycloalkyl, heterocycloalkyl, bicyclic cycloalkyl, bicyclic heterocycloalkyl, cycloalkenyl, cycloalkynyl, aryl or heteroaryl; or Where R 1 and R 2 together form a ring having 4 to 10 carbons; and The wavy bonds represent any geometric isomers.

5. The process of claim 1, which is carried out at a partial pressure of carbon monoxide of at least 1 atmosphere (atm).

6. The process according to claim 1, which is carried out at a partial pressure of carbon monoxide of 10-100 atmospheres (atm).

7. The process of claim 1 conducted at a partial pressure of carbon monoxide of about 40 atmospheres (atm).

8. The process of claim 1 which is carried out at a temperature of at least 70°C.

9. The method according to claim 1, which is carried out at a temperature of 50°C to 200°C.

10. The method according to claim 1, which is carried out at a temperature of 100°C to 130°C.

11. The process of claim 1 , which is carried out in a reactor substantially free of water.

12. The method of claim 1, which is performed under illumination from a light source.

13. The method of claim 12, wherein the light source has a wavelength of 300 to 500 nm. The method of claim 12 , wherein the light source has a wavelength of 350 to 430 nm.

15. The method of claim 12, wherein the light source has a wavelength of 350 to 390 nm.

16. The method of claim 1, wherein the carboxylic acid is formed in situ.

17. The method of claim 1, wherein the carboxylic acid has formula (II): Where R 3 It is C1-C 24 Alkyl, C1-C 24 Alkenyl, C1-C 24 Alkynyl, C1-C 24 Halogenated alkyl, C1-C 24 Halogenated alkenyl, C1-C 24 haloalkynyl, cycloalkyl, heterocycloalkyl, bicyclic cycloalkyl, bicyclic heterocycloalkyl, cycloalkenyl, cycloalkynyl, aryl or heteroaryl.

18. The method of claim 1, wherein the carboxylic acid has one more carbon atom than the ethylenically unsaturated compound.

19. The method of claim 1, wherein the ethylenically unsaturated compound is propylene, the carboxylic acid is isobutyric acid, and the organic anhydride is isobutyric anhydride.

20. The process of claim 19, further comprising cracking the isobutyric anhydride to produce dimethyl ketene and isobutyric acid, dimerizing two equivalents of dimethyl ketene to provide 2,2,4,4-tetramethyl-1,3-cyclobutanedione, and hydrogenating the 2,2,4,4-tetramethyl-1,3-cyclobutanedione to form 2,2,4,4-tetramethyl-1,3-cyclobutanediol.

21. The process according to claim 20, wherein the isobutyric acid is used to prepare isobutyric anhydride.

22. The method of claim 20, further comprising polymerizing the 2,2,4,4-tetramethyl-1,3-cyclobutanediol, optionally with one or more comonomers, to form a polyester.

23. The process of claim 19, conducted at a partial pressure of carbon monoxide of 30 atmospheres (atm).

24. The method of claim 19, which is performed over a period of 10 to 22 hours.

25. The method of claim 1, wherein the palladium compound is a palladium (0) or palladium (II) compound.

26. The method of claim 1, wherein the palladium compound is tris(dibenzylideneacetone)dipalladium(0), palladium chloride (π-cinnamyl) dimer, Pd(OAc)2, PdCl2, Pd(PhCN)2Cl2, Pd(MeCN)2Cl2, Pd(PPh3)2Cl2, Pd(COD)Cl2 or [Pd(π-allyl)Cl]2.

27. The method of claim 1, wherein the phosphine ligand is monodentate or bidentate.

28. The method of claim 1, wherein the phosphine ligand has formula (III) or (IV): Where R 4 -R 10 are independently halides, C1-C 24 Alkyl, C2-C 24 Alkenyl, C2-C 24 Alkynyl, C1-C 24 Halogenated alkyl, C2-C 24 Halogenated alkenyl, C2-C 20 haloalkynyl, cycloalkyl, heterocycloalkyl, bicyclic cycloalkyl, bicyclic heterocycloalkyl, cycloalkenyl, cycloalkynyl, aryl, heteroaryl, ferrocenyl, or OR 11 , where R 11 It is a halide, C1-C 24 Alkyl, C2-C 24 Alkenyl, C2-C 24 Alkynyl, C1-C 24 Halogenated alkyl, C2-C 24 Halogenated alkenyl, C2-C 24 haloalkynyl, cycloalkyl, heterocycloalkyl, bicyclic cycloalkyl, bicyclic heterocycloalkyl, cycloalkenyl, cycloalkynyl, aryl, heteroaryl or ferrocenyl; and wherein Q is C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, aryl, heteroaryl, heteroaryl, oxydibenzyl, ferrocenyl, quinolinyl, acridinyl, dihydroacridinyl, xanthenyl or 10H-phenoxazinyl.

29. The method of claim 28, wherein the phosphine ligand has formula (IV); Where R 7 -R 10 is independently cycloalkyl, heterocycloalkyl, bicyclic cycloalkyl, bicyclic heterocycloalkyl, cycloalkenyl, cycloalkynyl, aryl, heteroaryl, or ferrocenyl; and wherein Q is aryl, heteroaryl, heteroaralkyl, oxydibenzyl, ferrocenyl, quinolinyl, acridinyl, dihydroacridinyl, xanthenyl or 10H-phenoxazinyl.

30. The method of claim 28, wherein the phosphine ligand has the formula (IV), wherein R 7 -R 10 R is independently aryl, and Q is aryl, heteroaryl, heteroaralkyl, oxydibenzyl, ferrocenyl, quinolinyl, acridinyl, dihydroacridinyl, xanthenyl or 10H-phenoxazinyl.

31. The method of claim 30, wherein the phosphine ligand is bis[(2-diphenylphosphino)phenyl]ether (DPEphos) or Xantphos.

32. The method of claim 1 which is performed neat.

33. The method of claim 1, which is carried out in a solvent.

34. The method of claim 33, wherein the solvent is aromatic.

35. The method of claim 33, wherein the solvent is a halogenated, nitrile or ether solvent.

36. The method of claim 33, wherein the solvent is acetonitrile, chlorobenzene, dichloromethane, dichloroethane, trifluorotoluene, perfluorotoluene, tetrachloroethane, tetrahydrofuran, benzonitrile, chlorobenzene, pyridine, dibenzyl ether, xylene, toluene, methyl acetate, methyl propionate, ethyl acetate, propyl acetate, butyl acetate, isobutyl acetate, dimethylformamide or dimethyl sulfoxide.

37. The method of claim 1, wherein the catalyst system comprises a promoter additive.

38. The method of claim 37, wherein the promoter additive is an acid.

39. The method of claim 38, wherein the acid is an organic acid.

40. The method of claim 37, wherein the promoter additive is an acyl electrophile.

41. The method of claim 40, wherein the acyl electrophile is trifluoroacetic anhydride or acetic anhydride.

42. The method of claim 37, wherein the promoter additive is halogenated.

43. The method of claim 37, wherein the promoter additive is an aryl halide or a benzoyl halide.

44. The method of claim 38, wherein the acid is HCl.

45. A process for preparing a cyclic organic anhydride comprising contacting an ethylenically unsaturated carboxylic acid with carbon monoxide in the presence of a catalyst system obtainable by combining palladium or a palladium compound with a phosphine ligand.

46. ​​A process for preparing a poly(organic anhydride) comprising contacting a first compound having at least two ethylenically unsaturated groups with carbon monoxide and a second compound having at least two carboxylic acid groups in the presence of a catalyst system obtainable by combining palladium or a palladium compound with a phosphine ligand.

47. The process of claim 1 further comprising cracking the organic anhydride to produce dimethyl ketene and a carboxylic acid, dimerizing two equivalents of the dimethyl ketene to provide 2,2,4,4-tetramethyl-1,3-cyclobutanedione, and hydrogenating the 2,2,4,4-tetramethyl-1,3-cyclobutanedione to form 2,2,4,4-tetramethyl-1,3-cyclobutanediol.

48. The process of claim 47, wherein the produced carboxylic acid is used to prepare an organic anhydride.

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