Two-step synthesis of pyrrole compounds from furan compounds

Abstract

A pyrrole compound is produced by contacting a furan compound, a solid acid catalyst, and water to form a reaction mixture containing a γ-dicarbonyl compound, and then contacting the γ-dicarbonyl compound with ammonia or an ammonium salt to form a reaction product mixture containing the pyrrole compound. An exemplary pyrrole compound that can be synthesized using these processes is 2,5-dimethylpyrrole.

Description

[Technical Field]

[0001] This disclosure relates to a process for producing pyrrole compounds. More specifically, this disclosure relates to contacting a furan compound, a solid acid catalyst, and water to form a γ-dicarbonyl compound, and then converting this γ-dicarbonyl compound into a similar pyrrole compound. [Background technology]

[0002] Pyrrole compounds, such as 2,5-dimethylpyrrole, can be used as components of oligomerization catalyst systems for producing α-olefins such as 1-hexene or 1-octene from ethylene. However, synthetic schemes for producing pyrrole compounds and their γ-dicarbonyl precursors often suffer from one or more drawbacks, including low yields, the formation of numerous by-products, and the difficulty of isolating and purifying the desired γ-dicarbonyl precursor compound. Therefore, the present invention generally relates to synthetic schemes for producing pyrrole compounds that overcome these pointed-out drawbacks. [Overview of the project]

[0003] This summary is provided in a simplified form to introduce a set of concepts further described in the modes for carrying out the invention below. This summary is not intended to identify essential or intrinsic features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[0004] This specification discloses steps for producing pyrrole compounds. These steps may include: a) contacting a furan compound, a solid acid catalyst, and water to form a reaction mixture containing a γ-dicarbonyl compound; and b) contacting the γ-dicarbonyl compound with ammonia, an ammonium salt, or a combination thereof to form a reaction product mixture containing a pyrrole compound.

[0005] Although not limited thereto, in the processes described in this specification, the furan compound (F1), the γ-dicarbonyl compound (D1), and the pyrrole compound (P1) may have the following formulas.

Chemical formula

[0006] In these formulas, R, R 1 , R 2 , and R 3 are independently a hydrogen atom, a C1-C 30 organo group, or a C3-C 60 silyl group. In certain embodiments, R and R 1 can be a methyl group, and R 2 and R 3 can be a hydrogen atom.

[0007] Both the foregoing summary and the following detailed description are illustrative only and are merely for the purpose of explanation. Therefore, the foregoing summary and the following detailed description should not be regarded as limiting. Furthermore, in addition to what is described in this specification, features or variations may also be provided. For example, certain embodiments may be directed to various combinations and sub-combinations of the features described in the detailed description. In connection with the present invention, the following is further disclosed. [1] A process for producing pyrrole compounds, a) A reaction mixture containing a γ-dicarbonyl compound is formed by contacting a furan compound, a solid acid catalyst, and water. b) The step comprising contacting the γ-dicarbonyl compound with ammonia, an ammonium salt, or a combination thereof to form a reaction product mixture containing the pyrrole compound. [2] The furan compound (F1), the γ-dicarbonyl compound (D1), and the pyrrole compound (P1) have the following formula:

Chemical formula

[10] Step a) is, Temperatures in the range of 80°C to 180°C, and The process described in [1] is carried out at a pressure in the range of 25 to 150 psig.

[11] The process according to [1], wherein step a) is carried out in a water-to-furan compound molar ratio in the range of 0.5:1 to 10:1.

[12] The process according to [1], wherein step a) is carried out in a stirred tank reactor in a weight ratio of the furan compound to the solid acid catalyst in the range of 5:1 to 50:1.

[13] The step according to [1], wherein the conversion rate of the furan compound is at least 90 mol%.

[14] The step according to

[13] , wherein the yield to the γ-dicarbonyl compound is at least 80 mol%.

[15] Step a) is the process described in [1], carried out in a fixed-bed reactor with a furan compound WHSV in the range of 0.01 to 5.

[16] [1] The process described above, Prior to step b), a step of separating at least a portion of the γ-dicarbonyl compound from the reaction mixture, and / or The step further comprises, prior to step b), separating at least a portion of the solid acid catalyst from the reaction mixture.

[17] Step b) comprises contacting the γ-dicarbonyl compound with the ammonium salt, wherein the ammonium salt comprises ammonium hydroxide, ammonium acetate, ammonium carbonate, ammonium bicarbonate, ammonium chloride, ammonium nitrate, ammonium phosphate, ammonium sulfate, or any combination thereof, as described in [1].

[18] [1] The process described above, The reaction product mixture comprises an organic phase and an aqueous phase. The process further comprises, after step b), separating at least a portion of the water from the reaction product mixture.

[19] The process according to [1], wherein the pyrrole compound is produced in a yield of at least 70 mol% based on the furan compound.

[20] The process according to [1] further comprises, after step b), separating at least a portion of the pyrrole compound from the reaction product mixture.

[0008] The following drawings constitute part of this specification and are included to further support specific aspects of the invention. The invention can be better understood by referring to one or more of these drawings in combination with the detailed description and examples. [Brief explanation of the drawing]

[0009] [Figure 1] The gas chromatographic plot of the reaction mixture of Example 1 containing 2,5-hexanedione is shown. [Figure 2] The gas chromatographic plot of the reaction mixture of Example 2, which contains 2,5-hexanedione, is shown. [Figure 3] The gas chromatographic plot of the reaction mixture of Example 3, which contains 2,5-hexanedione, is shown.

[0010] definition To more clearly define the terms used herein, the following definitions are provided. Unless otherwise indicated, the following definitions apply to this disclosure. If a term is used in this disclosure but is not specifically defined herein, the definition from IUPAC Compendium of Chemical Terminology, 2nd Ed (1997) may apply, provided that the definition does not conflict with other disclosures or definitions applicable herein, or that it does not obscure or render ineffective the claim to which the definition applies. In the event of any conflict between any definition or usage provided in any document incorporated herein by reference and any definition or usage contained herein, the definition or usage contained herein shall prevail.

[0011] In this specification, subject matter features may be described in a manner that allows for different combinations of features to be assumed within a particular aspect and / or description. For each and all aspects, and / or descriptions, and / or features disclosed herein, all combinations that do not adversely affect the systems, compositions, processes, and / or methods described herein, whether or not a particular combination is explicitly stated, are considered. Furthermore, unless expressly stated otherwise, any combination of aspects, and / or descriptions, and / or features disclosed herein may be used to describe conceivable processes and systems consistent with this disclosure.

[0012] The terms “a,” “an,” and “the” are intended to include multiple options, for example, at least one option, unless otherwise specified. For example, the disclosure of “furan compounds” or “solid acid catalysts” means, unless otherwise specified, to include one or more mixtures or combinations of furan compounds or solid acid catalysts.

[0013] Generally, groups of elements are indicated using the numbering scheme shown in the version of the periodic table published in Chemical and Engineering News, 63(5), 27, 1985. In some cases, groups of elements may be indicated using the common name assigned to that group, for example, alkali metals for Group 1 elements, alkaline earth metals for Group 2 elements, transition metals for Groups 3-12 elements, and halogens or halides for Group 17 elements.

[0014] For any particular compound or group disclosed herein, any name or structure presented is intended to encompass all conformational isomers, positional isomers, stereoisomers, and mixtures thereof that may arise from a particular set of substituents, unless otherwise specified. This name or structure also encompasses all enantiomers, diastereomers, and other optical isomers (if any) that would be recognized by those skilled in the art, whether enantiomers, racemates, or mixtures of stereoisomers, unless otherwise specified. For example, a general reference to hexene (or hexenes) includes all linear or branched, acyclic or cyclic hydrocarbon compounds having six carbon atoms and one carbon-carbon double bond; a general reference to pentane includes n-pentane, 2-methylbutane, and 2,2-dimethylpropane; and a general reference to butyl group includes n-butyl, sec-butyl, iso-butyl, and t-butyl.

[0015] A chemical "group" is described according to how it is formally derived from a reference or "parent" compound, for example, by the number of hydrogen atoms formally removed from the parent compound to produce the group, even if the group is not literally synthesized in this manner. For example, an "alkyl group" can be formally derived by removing one hydrogen atom from an alkane, while an "alkylene group" can be formally derived by removing two hydrogen atoms from an alkane. Furthermore, a more general term can be used to encompass a variety of groups that are formally derived by removing any number ("one or more") hydrogen atoms from the parent compound, which in this example can be described as an "alkane group," which encompasses "alkyl groups" and "alkylene groups," and the material has three or more hydrogen atoms removed from the alkane, depending on the context. As a whole, disclosure of substituents, ligands or other chemical parts that can constitute a particular "group" means that, when the group is used as described, it follows well-known rules of chemical structure and bonding. When a group is described as "derived by," "derived from," "formed by," or "formed from," these terms are used in a formal sense and are not intended to reflect a specific method or procedure of synthesis unless otherwise specified or required by the context.

[0016] The term “organyl group” is used herein according to the definition specified in IUPAC and refers to an organic substituent having one free valence on a carbon atom, regardless of the type of functional group. Similarly, “organylene group” refers to an organic group derived from an organic compound by removing two hydrogen atoms, two hydrogen atoms from one carbon atom, or one hydrogen atom from each of two different carbon atoms, regardless of the type of functional group. “Organic group” refers to a generalized group formed by removing one or more hydrogen atoms from a carbon atom of an organic compound. Thus, “organyl group,” “organylene group,” and “organic group” may include organic functional groups and / or atoms other than carbon and hydrogen; that is, an organic group may include functional groups and / or atoms in addition to carbon and hydrogen. “Organyl group,” “organylene group,” or “organic group” may be aliphatic (including cyclic or acyclic, or linear or branched) or aromatic.

[0017] As used herein and in the claims, the term “hydrocarbon” refers to a compound containing only carbon and hydrogen. Other identifiers may be used to indicate the presence of a particular group in a hydrocarbon (for example, halogenated hydrocarbons indicate the presence of one or more halogen atoms that substitute for the same number of hydrogen atoms in the hydrocarbon). The term “hydrocarbyl group” is used herein according to the definition specified in IUPAC and is a monovalent group formed by removing a hydrogen atom from a hydrocarbon. Similarly, “hydrocarbylene group” refers to a group formed by removing two hydrogen atoms from a hydrocarbon (two hydrogen atoms from one carbon atom, or one hydrogen atom from each of two different carbon atoms). Thus, according to the terminology used herein, “hydrocarbon group” refers to a generalized group formed by removing one or more hydrogen atoms (as required for a particular group) from a hydrocarbon. “Hydrocarbyl group,” “hydrocarbylene group,” and “hydrocarbon group” may be acyclic or cyclic groups, and / or linear or branched. The "hydrocarbyl group," "hydrocarbylene group," and "hydrocarbon group" may include rings, ring systems, aromatic rings, and aromatic ring systems containing only carbon and hydrogen. Examples of members of the "hydrocarbyl group," "hydrocarbylene group," and "hydrocarbon group" include, in particular, aryl groups, arylene groups, arene groups, alkyl groups, alkylene groups, alkane groups, cycloalkyl groups, cycloalkylene groups, cycloalkane groups, aralkyl groups, alkylene groups, and aralkane groups.

[0018] As used herein and in the claims, the term “alkane” refers to a saturated hydrocarbon compound. Other identifiers may be used to indicate the presence of a particular group in an alkane (for example, a halide alkane indicates the presence of one or more halogen atoms substituting the same number of halogen atoms as hydrogen atoms in the alkane). The term “alkyl group” is used herein according to the definition specified in IUPAC and refers to a monovalent group formed by removing a hydrogen atom from an alkane. Similarly, “alkylene group” refers to a group formed by removing two hydrogen atoms from an alkane (two hydrogen atoms from one carbon atom, or one hydrogen atom from two different carbon atoms). “Alkane group” is a general term referring to a group formed by removing one or more hydrogen atoms (required for a particular group) from an alkane. Unless otherwise specified, “alkyl group,” “alkylene group,” and “alkane group” may be acyclic or cyclic, and / or linear or branched. Primary, secondary, and tertiary alkyl groups are derived by removing a hydrogen atom from the primary, secondary, or tertiary carbon atoms of an alkane, respectively. n-alkyl groups can be derived by removing a hydrogen atom from the terminal carbon atom of a linear alkane.

[0019] The term “substituted” is intended to be non-limiting when used to describe a compound or group, for example, when referring to a substituted analogue of a particular compound or group, and is intended to describe any non-hydrogen moiety that formally replaces a hydrogen in that group. One or more groups may also be referred to herein by equivalent terms such as “unsubstituted” or “unsubstituted,” which refers to the original group in which the non-hydrogen moiety does not substitute a hydrogen in that group. “Substituted” is non-limiting and is intended to include inorganic or organic substituents.

[0020] The term "γ-dicarbonyl compound" refers to a compound having two ketone groups, two aldehyde groups, or one aldehyde group and one ketone group, separated by two consecutive carbon atoms. A γ-dicarbonyl compound must contain at least two groups in the specified relationship, but these compounds may further contain additional aldehyde and / or ketone groups, which may or may not have the specified relationship. Furthermore, unless otherwise specified, a γ-dicarbonyl compound may contain other heteroatoms and / or functional groups (e.g., ester or amide groups).

[0021] Features provided as minimum values ​​in this disclosure may alternatively be described as "at least" or "greater than" any minimum value described in the features disclosed herein. Features provided as maximum values ​​in this disclosure may alternatively be described as "less than" or "less than" any maximum value described in the features disclosed herein.

[0022] Within this disclosure, the usual rules of organic nomenclature prevail. For example, when referring to a substituted compound or group, a reference to a substitution pattern is considered to indicate that the indicated group(s) are at the indicated position and all other unindicated positions are hydrogen. For example, a reference to a 4-substituted phenyl group indicates that there is a non-hydrogen substituent at position 4 and hydrogens at positions 2, 3, 5, and 6. A reference to a compound or group having a substitution at a position in addition to the indicated position may be made using "inclusive" or other alternative language. For example, a reference to a phenyl group with a substituent at position 4 refers to a phenyl group having a non-hydrogen substituent at position 4 and hydrogens or any non-hydrogen substituents at positions 2, 3, 5, and 6.

[0023] The term “contact” is used herein to describe systems, compositions, processes, and methods in which components come into contact or combine in any order, in any manner, and for any length of time, unless otherwise specified. For example, components can be combined by compounding or mixing using any suitable technique. In this specification, a reaction product mixture or reaction mixture is obtained by “contacting” two or more components.

[0024] In this disclosure, compositions and processes are described using the term "containing" various components or steps, but unless otherwise specified, compositions and processes may also "substantially consist of" or "consist of" various components or steps.

[0025] The yields of all disclosed products are based on the limiting reactants in each reaction, unless otherwise specified. For example, in a catalytic step, the limiting reactant for producing a γ-dicarbonyl compound may be a furan compound; therefore, the yield of the γ-dicarbonyl compound will be based on the initial amount of the furan compound. In non-catalytic reactions or transformations, the limiting reactant is a reactant that is not present in sufficient moles to react with the other reactants in a stoichiometric amount.

[0026] Any methods and materials similar to or equivalent to those described herein may be used in carrying out or testing the processes and reaction systems, but typical methods and materials are described herein.

[0027] All publications and patents referenced herein are incorporated herein by reference for the purpose of describing and disclosing, for example, the structures and methodologies described in such publications that may be used in connection with this disclosure. [Modes for carrying out the invention]

[0028] Disclosed herein is a process for producing a pyrrole compound, comprising contacting a furan compound, a solid acid catalyst, and water to form a reaction mixture containing a γ-dicarbonyl compound, and contacting the γ-dicarbonyl compound with ammonia, an ammonium salt, or a combination thereof to form a reaction product mixture containing a pyrrole compound. Generally, the features of the process for producing the pyrrole compound (e.g., in particular the furan compound, the dicarbonyl compound, the pyrrole compound, the solid acid catalyst, the ammonium salt, the conditions under which the dicarbonyl compound is formed, and the conditions under which the pyrrole compound is formed) are described independently herein, and these features may be used in any combination without limitation to further describe the disclosed process for producing the pyrrole compound. Furthermore, additional process steps may be performed before, during, and / or after any step of the disclosed process, and may be used in any combination without limitation to further describe the pyrrole synthesis process, unless otherwise specified.

[0029] Advantageously, the process disclosed herein provides remarkably high conversion rates of furan compounds and yields to γ-dicarbonyl compounds while minimizing by-products. Furthermore, the dicarbonyl compounds can be easily isolated and purified before conversion to the desired pyrrole compounds.

[0030] Synthesis of Gamma Dicarbonyl Compounds In step a) of the process for producing a pyrrole compound, a furan compound, a solid acid catalyst, and water can be brought into contact to form a reaction mixture containing a γ-dicarbonyl compound. The furan compound (F1) and the γ-dicarbonyl compound (D1) in step a) are not limited to these, but may have the following formulas. [ka]

[0031] In these formulas, R, R 1 , R 2 , and R 3These are, independently, hydrogen atoms, C1~C 30 organyl group, or C3~C 60 It can be a silyl group. R, R 1 , R 2 , and R 3 It is considered that either of these may be the same or different.

[0032] In one embodiment, R, R 1 , R 2 , and R 3 These are, independently, hydrogen, C1~C 18 Organyl group (for example, C1~C 18 Hydrocarbyl group), or C3~C 48 It may be a silyl group. In another embodiment, R, R 1 , R 2 , and R 3 These are, independently, hydrogen, C1~C 12 Organyl group (for example, C1~C 12 Hydrocarbyl group), or C3~C 36 It can be a silyl group. In yet another embodiment, R, R 1 , R 2 , and R 3 These are independently hydrogen, C1-C8 organyl groups (e.g., C1-C8 hydrocarbyl groups), or C3-C 24 It can be a silyl group. Therefore, R, R 1 , R 2 , and R 3 These are independently hydrogen or C1~C 18 Hydrocarbyl group (or C1~C 12 Alternatively, it could be a C1-C8 hydrocarbyl group.

[0033] In one embodiment, R, R 1 , R 2 , and / or R 3Any of these may independently be an alkyl group, a substituted alkyl group, a cycloalkyl group, a substituted cycloalkyl group, an aryl group, a substituted aryl group, an aralkyl group, or a substituted aralkyl group; or an alkyl group, a substituted alkyl group; or a cycloalkyl group, a substituted cycloalkyl group; or an aryl group, a substituted aryl group; or an aralkyl group, a substituted aralkyl group; or an alkyl group, a cycloalkyl group, a substituted alkyl group; or a cycloalkyl group, a substituted cycloalkyl group; or an aryl group, a substituted aryl group; or an aralkyl group; or a substituted aralkyl group. In any embodiment disclosed herein, the alkyl group is C1-C 20 , C1~C 10 , or C1-C5 alkyl groups. In any embodiment disclosed herein, the substituted alkyl group is C1-C 20 , C1~C 10 , or C1-C5 substituted alkyl groups. In any embodiment disclosed herein, the cycloalkyl group is C4-C 20 , C4~C 15 , or C4~C 10 It may be a cycloalkyl group. In any embodiment disclosed herein, the substituted cycloalkyl group is C4-C 20 , C4~C 15 , or C4~C 10 It may be a substituted cycloalkyl group. In any embodiment disclosed herein, the aryl group is C6-C 20 , C6~C 15 , or C6~C 10 It may be an aryl group. In any embodiment disclosed herein, the substituted aryl group is C6-C 20 , C6~C 15 , or C6~C 10 It may be a substituted aryl group. In any embodiment disclosed herein, the aralkyl group is C7-C 20 , C7~C 15 , or C7~C10 It may be an aralkyl group. In any embodiment disclosed herein, the substituted aralkyl group is C7-C 20 , C7~C 15 , or C7~C 10 It may be a substituted aralkyl group. Each substituent of a substituted alkyl group (general or specific), substituted cycloalkyl group (general or specific), substituted aryl group (general or specific), and / or substituted aralkyl group (general or specific) may be a halogen, a hydrocarbyl group, or a hydrocarboxyl group, or a halogen or a hydrocarbyl group, or a halogen or a hydrocarboxyl group, or a halogen or a hydrocarbyl group, or a halogen or a hydrocarboxyl group, or a halogen or a hydrocarbyl group, or a hydrocarboxyl group. Substituted halogens, substituted hydrocarbyl groups (general and specific), and substituted hydrocarboxyl groups (general and specific) are disclosed separately herein. These substituted halogens, substituted hydrocarbyl groups, and substituted hydrocarboxyl groups are substituted R, R 1 , R 2 , and / or R 3 It can be used without restriction to further explain the basis.

[0034] In one embodiment, R, R 1 , R 2 , and / or R 3 Any of these may independently be a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, or an octyl group, or a methyl group, an ethyl group, an n-propyl(1-propyl) group, an iso-propyl(2-propyl) group, a tert-butyl(2-methyl-2-propyl) group, or a neopentyl(2,2-dimethyl-1-propyl) group. In some embodiments, R, R 1 , R 2 , and / or R 3The alkyl group that can be used as any of them may be substituted. Each substituent of the substituted alkyl group (general or specific) can independently be a halogen or a hydrocarboxy group, or can be a halogen, or can be a hydrocarboxy group. Substituted halogens and substituted hydrocarboxy groups (general and specific) are independently disclosed herein. These substituted halogens and substituted hydrocarboxy groups are R, R 1 、R 2 、and / or R 3 and can be used without limitation to further describe the substituted alkyl group that can be used as any of them.

[0035] In one aspect, any of R, R 1 、R 2 、and / or R 3 can independently be a cyclopentyl group, a substituted cyclopentyl group, a cyclohexyl group, or a substituted cyclohexyl group, or can be a cyclopentyl group or a substituted cyclopentyl group, or can be a cyclohexyl group or a substituted cyclohexyl group. In one aspect, the substituted cycloalkyl group that can be used as any of R, R 1 、R 2 、and / or R 3 can be a 2-substituted cyclohexyl group, a 2,6-disubstituted cyclohexyl group, a 2-substituted cyclopentyl group, or a 2,5-disubstituted cyclopentyl group, or can be a 2-substituted cyclohexyl group or a 2,6-disubstituted cyclohexyl group, or can be a 2-substituted cyclopentyl group or a 2,5-disubstituted cyclopentyl group, or can be a 2-substituted cyclohexyl group or a 2-substituted cyclopentyl group, or can be a 2,6-disubstituted cyclohexyl group or a 2,5-disubstituted cyclopentyl group. In one aspect, any of R, R 1 、R 2 、and / or R 3One or more substituents of a polysubstituted cycloalkyl group used as either of the above may be the same or different, or all substituents of the polysubstituted cycloalkyl group may be the same, or all substituents of the polysubstituted cycloalkyl group may be different. Each substituent of a substituted cycloalkyl group having a specific number of ring carbon atoms may independently be a halogen, a hydrocarbyl group, or a hydrocarboxy group, or a halogen or a hydrocarbyl group, or a halogen or a hydrocarboxy group, or a hydrocarbyl group, or a halogen, or a hydrocarbyl group, or a hydrocarboxy group. Substituted halogens, substituted hydrocarbyl groups (general and specific), and substituted hydrocarboxy groups (general and specific) are disclosed separately herein. These substituted halogens, substituted hydrocarbyl groups, and substituted hydrocarboxy groups are R, R 1 , R 2 , and / or R 3 Substituted cycloalkyl groups (general or specific) that can be used as either of the above may be used without limitation to further describe them.

[0036] In non-restrictive forms, R, R 1 , R 2 , and / or R 3 Any of these may independently be a cyclohexyl group, a 2-alkylcyclohexyl group, or a 2,6-dialkylcyclohexyl group, or a cyclopentyl group, a 2-alkylcyclopentyl group, or a 2,5-dialkylcyclopentyl group. Alkyl substituents (general and specific) are described independently herein, and these alkyl substituents are R, R 1 , R 2 , and / or R 3Alkylcyclohexyl groups (general and specific), dialkylcyclohexyl groups (general and specific), alkylcyclopentyl groups (general or specific), and / or dialkylcyclopentyl groups (general and specific) which can be used as any of the above may be used without limitation to further describe them. Generally, the alkyl substituents of the dialkylcyclohexyl group or the dialkylcyclopentyl group may be the same, or the alkyl substituents of the dialkylcyclohexyl group or the dialkylcyclopentyl group may be different. In some non-limiting embodiments, R, R 1 , R 2 , and / or R 3 Any of these may independently be a 2-methylcyclohexyl group, a 2-ethylcyclohexyl group, a 2-isopropylcyclohexyl group, a 2-tert-butylcyclohexyl group, a 2,6-dimethylcyclohexyl group, a 2,6-diethylcyclohexyl group, a 2,6-diisopropylcyclohexyl group, or a 2,6-di-tert-butylcyclohexyl group. In other non-limiting embodiments, R, R 1 , R 2 , and / or R 3 Any of these may independently be a 2-methylcyclohexyl group, a 2-ethylcyclohexyl group, a 2-isopropylcyclohexyl group, a 2-tert-butylcyclohexyl group, or a 2,6-dimethylcyclohexyl group, a 2,6-diethylcyclohexyl group, a 2,6-diisopropylcyclohexyl group, or a 2,6-di-tert-butylcyclohexyl group.

[0037] In one embodiment, R, R 1 , R 2 , and / or R 3 Any of these may independently be a phenyl group or a substituted phenyl group, or a phenyl group, or a substituted phenyl group. In one embodiment, R, R 1 , R 2 , and / or R 3The substituted phenyl group that can be used as any of the following may be a 2-substituted phenyl group, a 3-substituted phenyl group, a 4-substituted phenyl group, a 2,4-disubstituted phenyl group, a 2,6-disubstituted phenyl group, a 3,5-disubstituted phenyl group, or a 2,4,6-trisubstituted phenyl group; or a 2-substituted phenyl group, a 4-substituted phenyl group, a 2,4-disubstituted phenyl group, or a 2,6-disubstituted phenyl group; or a 3-substituted phenyl group or a 3,5-disubstituted phenyl group; or a 2-substituted phenyl group or a 4-substituted phenyl group; or a 2,4-disubstituted phenyl group or a 2,6-disubstituted phenyl group; or a 2,4,6-trisubstituted phenyl group. In one embodiment, R, R 1 , R 2 , and / or R 3 One or more substituents of a polysubstituted phenyl group used as either of the above may be the same or different, or all substituents of a polysubstituted phenyl group may be the same, or all substituents of a polysubstituted phenyl group may be different. Each substituent of a substituted phenyl group (general or specific) may independently be a halogen, a hydrocarbyl group or a hydrocarboxyl group, or a halogen or a hydrocarbyl group, or a halogen or a hydrocarboxyl group, or a halogen or a hydrocarbyl group, or a hydrocarboxyl group. Substituted halogens, substituted hydrocarbyl groups (general and specific), and substituted hydrocarboxyl groups (general and specific) are disclosed separately herein. These substituted halogens, substituted hydrocarbyl groups, and substituted hydrocarboxyl groups are R, R 1 , R 2 , and / or R 3 This may be used without limitation to further describe substituted phenyl groups (general or specific) that can be used as either of the above.

[0038] In non-restrictive forms, R, R 1 , R 2 , and / or R 3Any of these may independently be a phenyl group, a 2-alkylphenyl group, a 3-alkylphenyl group, a 4-alkylphenyl group, a 2,4-dialkylphenyl group, a 2,6-dialkylphenyl group, a 3,5-dialkylphenyl group, or a 2,4,6-trialkylphenyl group; or a 2-alkylphenyl group, a 4-alkylphenyl group, a 2,4-dialkylphenyl group, a 2,6-dialkylphenyl group, or a 2,4,6-trialkylphenyl group; or a 2-alkylphenyl group or a 4-alkylphenyl group; or a 2,4-dialkylphenyl group or a 2,6-dialkylphenyl group; or a 3-alkylphenyl group or a 3,5-dialkylphenyl group; or a 2-alkylphenyl group or a 2,6-dialkylphenyl group; or a 2,4,6-trialkylphenyl group. Alkyl substituents (general and specific) are described separately herein, and these alkyl substituents are R, R 1 , R 2 , and / or R 3 To further describe any alkyl-substituted phenyl group that can be used as either of the following, the terms may be used without limitation. Generally, the alkyl substituents of a dialkylphenyl group (general or specific) or a trialkylphenyl group (general or specific) may be the same, or the alkyl substituents of a dialkylphenyl group or a trialkylphenyl group may be different. In some non-limiting embodiments, R, R 1 , R 2 , and / or R 3Any of these may independently be a phenyl group, a 2-methylphenyl group, a 2-ethylphenyl group, a 2-n-propylphenyl group, a 2-isopropylphenyl group, a 2-tert-butylphenyl group, a 2,6-dimethylphenyl group, a 2,6-diethylphenyl group, a 2,6-di-n-propylphenyl group, a 2,6-diisopropylphenyl group, a 2,6-di-tert-butylphenyl group, a 2-isopropyl-6-methylphenyl group, or a 2,4,6-trimethylphenyl group, or It may be a phenyl group, a 2-methylphenyl group, a 2-ethylphenyl group, a 2-n-propylphenyl group, a 2-isopropylphenyl group, or a 2-tert-butylphenyl group, or it may be a phenyl group, a 2,6-dimethylphenyl group, a 2,6-diethylphenyl group, a 2,6-di-n-propylphenyl group, a 2,6-diisopropylphenyl group, a 2,6-di-tert-butylphenyl group, a 2-isopropyl-6-methylphenyl group, or a 2,4,6-trimethylphenyl group.

[0039] In one embodiment, R, R 1 , R 2 , and / or R 3 Any of these may independently be a benzyl group or a substituted benzyl group, or a benzyl group, or a substituted benzyl group. Each substituent of the substituted benzyl group may independently be a halogen, a hydrocarbyl group, or a hydrocarboxy group, or a halogen or a hydrocarbyl group, or a halogen or a hydrocarboxy group, or a hydrocarbyl group, or a halogen, or a hydrocarbyl group, or a hydrocarboxy group. Substituted halogens, substituted hydrocarbyl groups (general and specific), and substituted hydrocarboxy groups (general and specific) are disclosed separately herein. These substituted halogens, substituted hydrocarbyl groups, and substituted hydrocarboxy groups are R, R 1 , R 2 , and / or R 3 Substitutive benzyl groups (general or specific) that can be used as either of the above may be used without limitation to further describe them.

[0040] In one embodiment, R, R 1 , R 2 , and / or R 3 Any of these can independently be an acyl group or a substituted acyl group, or can be an acyl group, or can be a substituted acyl group. In one embodiment, the acyl group is C1~C 20 , C1~C 15 , C1~C 10 , or C1-C5 acyl groups. In one embodiment, the substituted acyl group is C1-C 20 , C1~C 15 , C1~C 10 , or C1-C5 substituted acyl groups. In some embodiments, R, R 1 , R 2 , and / or R 3 Any of these may independently be an alkanoyl group, a substituted alkanoyl group, a benzoyl group, or a substituted benzoyl group, or an alkanoyl group or a substituted alkanoyl group, or a benzoyl group or a substituted benzoyl group, or an alkanoyl group, or a substituted alkanoyl group, or a benzoyl group, or a substituted benzoyl group. In any embodiment disclosed herein, the alkanoyl group is C1-C 20 , C1~C 10 , or C1-C5 alkanoyl groups. In any embodiment disclosed herein, the substituted alkanoyl group is C1-C5 20 , C1~C 10 , or C1-C5 substituted alkanoyl groups. In any embodiment disclosed herein, the benzoyl group is C7-C 20 , C7~C 15 , or C7~C 10 It may be a benzoyl group. In any embodiment disclosed herein, the substituted benzoyl group is C7-C 20 , C1~C 15 , or C1~C 10It may be a substituted benzoyl group. Each substituent of the substituted alkanoyl group (general or specific) and / or substituted benzoyl group (general or specific) may be a halogen, a hydrocarbyl group or a hydrocarboxyl group, or a halogen or a hydrocarbyl group, or a halogen or a hydrocarboxyl group, or a halogen or a hydrocarbyl group, or a hydrocarboxyl group, or a halogen, or a hydrocarbyl group, or a hydrocarboxyl group. Substituted halogens, substituted hydrocarbyl groups (general and specific), and substituted hydrocarboxyl groups (general and specific) are disclosed separately herein. These substituted halogens, substituted hydrocarbyl groups, and substituted hydrocarboxyl groups are R, R 1 , R 2 , and / or R 3 Substituted alkanoyl groups and / or substituted benzoyl groups that can be used as either of the above may be used without limitation to further describe them.

[0041] The various embodiments described herein refer to nonhydrogen substituents such as halogens (or halos, halides), hydrocarbyl, hydrocarboxy, alkyl, and / or alkoxy substituents. In one embodiment, each nonhydrogen substituent in any embodiment for which a substituent is sought may be a halogen, a hydrocarbyl group, or a hydrocarboxy group, or a halogen or a hydrocarbyl group, or a halogen or a hydrocarboxy group, or a hydrocarbyl group, or a halogen, or a hydrocarbyl group, or a hydrocarboxy group. Each hydrocarbyl substituent may independently be C1-C 10 It may be a hydrocarbyl group or a C1-C5 hydrocarbyl group. Each hydrocarboxy substituent is independently a C1-C5 group. 10It may be a hydrocarboxyl group or a C1-C5 hydrocarboxyl group. Each halide substituent may independently be a fluoride, chloride, bromide, or iodide, or it may be a fluoride or chloride, or it may be a fluoride, or it may be a chloride, or it may be a bromide, or it may be an iodide.

[0042] In one embodiment, any hydrocarbyl substituent may independently be an alkyl group, an aryl group, or an aralkyl group, or may be an alkyl group, or may be an aryl group, or may be an aralkyl group. In one embodiment, any alkyl substituent may independently be a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an sec-butyl group, an isobutyl group, a tert-butyl group, an n-pentyl group, an 2-pentyl group, an 3-pentyl group, an 2-methyl-1-butyl group, a tert-pentyl group, an 3-methyl-1-butyl group, an 3-methyl-2-butyl group, or a neopentyl group, or may be a methyl group, an ethyl group, an ethyl group, an isopropyl group, a tert-butyl group, or a neopentyl group. In one embodiment, any aryl substituent may independently be a phenyl group, a tolyl group, a xylyl group, or a 2,4,6-trimethylphenyl group, or may be a phenyl group, or may be a tolyl group, or may be a xylyl group, or may be a 2,4,6-trimethylphenyl group. In one embodiment, any aralkyl substituent may independently be a benzyl group or an ethylphenyl group (2-phenyletho-1-yl or 1-phenyletho-1-yl), or may be a benzyl group, or may be an ethylphenyl group, or may be a 2-phenyletho-1-yl group, or may be a 1-phenyletho-1-yl group.

[0043] In one embodiment, any hydrocarboxy substituent may independently be an alkoxy group, an aryloxy group, or an aralkoxy group. In one embodiment, any alkoxy substituent may independently be a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, an isobutoxy group, a tert-butoxy group, an n-pentoxy group, a 2-pentoxy group, a 3-pentoxy group, a 2-methyl-1-butoxy group, a tert-pentoxy group, a 3-methyl-1-butoxy group, a 3-methyl-2-butoxy group, or a neopentoxy group; or a methoxy group, an ethoxy group, an isopropoxy group, an isopropoxy group, a tert-butoxy group, or a neopentoxy group. In one embodiment, any aryloxy substituent may independently be a phenoxy group, a trooxy group, a xyloxy group, or a 2,4,6-trimethylphenoxy group, or it may be a phenoxy group, or a trooxy group, or a xyloxy group, or a 2,4,6-trimethylphenoxy group. In one embodiment, any aralkoxy substituent may independently be a benzooxy group.

[0044] In one embodiment, R, R 1 , R 2 , and / or R 3 Either of these is independent of C3~C 60 It can be a silyl group, or C3~C 48 It can be a silyl group, or C3~C 36 It can be a silyl group, or C3~C 24 It can be a silyl group, or C3~C 15 It can be a silyl group. In some embodiments, R, R 1 , R 2 , and / or R 3 A silyl group that can be any of the above may have the formula (Si1). [ka]

[0045] Generally, the R of a silyl group having formula Si1 1s , R 2s , and R 3s R can independently be an organyl group or a hydrocarbyl group, or it can be an organyl group or it can be a hydrocarbyl group. 1s , R 2s and R 3s The organyl and / or hydrocarbyl groups that can be used as such may have the same number of carbon atoms as the organyl and hydrocarbyl groups disclosed herein as non-hydrogen furan substituents and dicarbonyl substituents. For example, R 1s , R 2s , and R 3s These are, independently, C1~C 15 It may be a hydrocarbyl group. In one embodiment, the R of a silyl group having formula Si1 1s , R 2s , and R 3s This can be independently an alkyl group, a substituted alkyl group, a cycloalkyl group, a substituted cycloalkyl group, an aryl group, a substituted aryl group, an aralkyl group, or a substituted aralkyl group, or an alkyl group, or a substituted alkyl group, or a cycloalkyl group, or a substituted cycloalkyl group, or an aryl group, or a substituted aryl group, or an aralkyl group, or a substituted aralkyl group. Alkyl groups, substituted alkyl groups, cycloalkyl groups, substituted cycloalkyl groups, aryl groups, substituted aryl groups, aralkyl groups, and substituted aralkyl groups are described herein independently as potential nonhydrogen furan substituents and dicarbonyl substituents, and R of a silyl group having formula Si1 1s , R 2s , and R 3s It can be used without restriction.

[0046] In one embodiment, R, R 1 , R 2 , and / or R 3Any silyl group that can be used as either of the following may independently be a trihydrocarbyl silyl group. In some embodiments, the silyl group may be a trialkylsilyl group (e.g., trimethylsilyl, triethylsilyl, triisopropylsilyl, or tri-t-butylsilyl), a triphenylsilyl, or a tri(substituted phenyl)silyl group, or a trialkylsilyl, or a triphenylsilyl, or a tri(substituted phenyl)silyl group. The hydrocarbyl group, alkyl group, and substituted phenyl group are described herein independently as potential nonhydrogen furan substituents and dicarbonyl substituents, and the R of the silyl group having formula Si1 1s , R 2s , and R 3s It can be used without restriction.

[0047] In some aspects of this specification, R, R 1 , R 2 , and R 3 At least one of them is not a hydrogen atom. For example, R and R 1 These are, independently, C1~C 18 It can be a hydrocarbyl group, R 2 and R 3 R can be a hydrogen atom. Suitable hydrocarbyl groups are disclosed herein, and R and R 1 R and R are independently of each other, for example, a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, a t-butyl group, a phenyl group, a benzyl group, a tolyl group, or a xylyl group. In certain embodiments, R and R 1 It can be a methyl group, R 2 and R 3 It can be hydrogen.

[0048] In one embodiment, the furan compounds used in the disclosed process are 2,5-dimethylfuran, 2,5-diethylfuran, 2-ethyl-5-methylfuran, 2-ethyl-5-n-propylfuran, 2,5-di-n-propylfuran, 2,5-diisopropylfuran, 2,5-di-n-butylfuran, 2,5-di-n-pentylfuran, 2,5-di-n-hexylfuran, 2,5-di-n-heptylfuran, and 2,5-di-n-o Cutylfuran, 2,3,5-triethylfuran, 2,3,5-tri-n-butylfuran, 2,3,5-tri-n-pentylfuran, 2,3,5-tri-n-hexylfuran, 2,3,5-tri-n-heptylfuran, 2,3,5-tri-n-octylfuran, 2,3,4,5-tetraethylfuran, 2,3,4,5-tetra-n-butylfuran, 2,3,4,5-tetra-n-hexylfuran, 2,5-dibenzylfuran This may include (or consist of, or consist of) any combination thereof, such as 2,4-dimethylfuran, 2-methyl-4-isopropylfuran, 2,4-dimethyl-3-ethylfuran, 2,4-diethylfuran, 2-ethyl-4-isopropylfuran, 2-methyl-4-sec-butylfuran, 2-ethyl-4-sec-butylfuran, 2-methyl-4-isobutylfuran, 2-ethyl-4-isobutylfuran, 2-methyl-4-t-butylfuran, 2-ethyl-4-t-butylfuran, 2-methyl-4-neopentylfuran, 2-ethyl-4-neopentylfuran, 3,4-dimethylfuran, 3,4-diethylfuran, 3,4-diisopropylfuran, 3,4-di-sec-butylfuran, 3,4-diisobutylfuran, 3,4-di-t-butylfuran, 3,4-di-neopentylfuran, etc. In certain embodiments consistent with the present invention, the furan compound used in the disclosed process may include (or essentially consist of, or consist of) 2,5-dimethylfuran.

[0049] Surprisingly, step a) for producing the γ-dicarbonyl compound in this specification is particularly effective when the furan compound and solid acid catalyst are brought into contact with water. While we do not wish to be bound by theory, the improvement in reaction yield and conversion rate observed when water is used is thought to be a result of water promoting the reaction between the furan compound and the solid acid catalyst, for example, by stabilizing the transition state between one or more reactants and their products or intermediates. However, water can increase the conversion rate of the furan compound and the yield to the γ-dicarbonyl compound by any other means.

[0050] In general, the appropriate procedure for contact (or reaction) in step a) is not particularly limited. For example, the furan compound, the solid acid catalyst, and water can be contacted in any order, method, or process that produces an acceptable yield of the γ-dicarbonyl compound. In one embodiment, the furan compound can be mixed with water before contact with the solid acid catalyst.

[0051] Certain ratios of components in step a) may prove advantageous with respect to the furan conversion rate and the yield of the γ-dicarbonyl compound. For example, step a) can be carried out with a minimum water-to-furan compound molar ratio of at least 0.25:1, 0.5:1, 1:1, or 1.5:1, and additionally or alternatively, step a) can be carried out with a maximum water-to-furan compound molar ratio of 50:1, 25:1, 10:1, 7.5:1, or 5:1 or less. In general, the water-to-furan compound molar ratio can be within the range from any minimum molar ratio disclosed herein to any maximum molar ratio disclosed herein. Thus, non-limiting ranges suitable for the water-to-furan compound molar ratio may include 0.25:1 to 50:1, 1:1 to 50:1, 0.5:1 to 25:1, 0.5:1 to 10:1, 1:1 to 10:1, 1:1 to 7.5:1, or 1.5:1 to 5:1. Other ranges suitable for the water-to-furan compound molar ratio in step a) can be readily found from this disclosure.

[0052] Typically, step a) can be performed at a pressure sufficient to maintain the water in the liquid phase. For example, step a) can be performed at a pressure of at least 5 psig (34 kPa), 10 psig (69 kPa), 25 psig (172 kPa), 40 psig (276 kPa), or 50 psig (345 kPa), and additionally or alternatively, step a) can be performed at a pressure of 200 psig (1.38 MPa), 175 psig (1.21 MPa), 150 psig (1.03 MPa), or 125 psig (0.86 MPa) or less. Generally, the pressure in step a) can be within the range of any minimum pressure to any maximum pressure disclosed herein. Therefore, suitable non-limiting pressure ranges for step a) may include 5 psig (34 kPa) to 200 psig (1.38 MPa), 10 psig (69 kPa) to 200 psig (1.38 MPa), 25 psig (172 kPa) to 175 psig (1.21 MPa), 25 psig (172 kPa) to 150 psig (1.03 MPa), 40 psig (276 kPa) to 150 psig (1.03 MPa), or 50 psig (345 kPa) to 125 psig (0.86 MPa). Other suitable pressure ranges for step a) and the formation of the γ-dicarbonyl compound are readily apparent from this disclosure. These pressure ranges also mean that they encompass situations in which step a) (or the formation of the γ-dicarbonyl compound) takes place at a series of different pressures rather than a single fixed pressure within each of these pressure ranges.

[0053] In one embodiment, step a) can be carried out at any temperature below the maximum operating temperature (or thermal stability temperature) of the solid acid catalyst. In another embodiment, step a) can be carried out at any temperature below the melting temperature of the solid acid catalyst, or step a) can be carried out at any temperature below the softening point / temperature of the solid acid catalyst. For example, depending on the particular solid acid catalyst, step a) can be carried out at a minimum temperature of 80°C, 90°C, 100°C, 110°C, or 120°C, and additionally or alternatively at a maximum temperature of 180°C, 170°C, 155°C, or 150°C. Generally, the temperature in step a) can be within the range of any minimum temperature to any maximum temperature disclosed herein. Therefore, suitable non-limiting temperature ranges for step a) and the formation of the γ-dicarbonyl compound may include 80°C to 180°C, 80°C to 155°C, 90°C to 170°C, 90°C to 155°C, 100°C to 170°C, 100°C to 155°C, 110°C to 170°C, 110°C to 150°C, 120°C to 180°C, 120°C to 175°C, or 120°C to 150°C. Other suitable temperatures and temperature ranges are readily found in this disclosure. These temperature ranges also mean that they encompass situations in which step a) (or the formation of the γ-dicarbonyl compound) takes place at a series of different temperatures rather than a single fixed temperature within each of these temperature ranges.

[0054] In one embodiment, step a) may be carried out in a stirred-tank reactor. In the stirred-tank reactor, the time for contacting the furan compound, the solid acid catalyst, and water (or for forming the γ-dicarbonyl compound) is not particularly limited and can be carried out for any suitable time. Nevertheless, the minimum average residence time in the stirred-tank reactor in step a) may be 5 minutes, 10 minutes, 15 minutes, 30 minutes, or 1 hour, and additionally or alternatively, the maximum average residence time may be 10 hours, 8 hours, 7 hours, 5 hours, or 3 hours. In general, the average residence time in the stirred-tank reactor in step a) may be within the range from any minimum time disclosed herein to any maximum time disclosed herein. Thus, non-limiting ranges suitable for the average residence time may include 5 minutes to 10 hours, 10 minutes to 8 hours, 15 minutes to 7 hours, 30 minutes to 5 hours, 30 minutes to 3 hours, 1 hour to 10 hours, 1 hour to 7 hours, 1 hour to 5 hours, or 1 hour to 3 hours. Other appropriate ranges for average dwell time can be readily found from this disclosure.

[0055] The weight ratio (furan:catalyst) of the furan compound to the solid acid catalyst in the stirred-tank reactor is not particularly limited. In one embodiment, step a) can be carried out with a minimum furan-to-catalyst weight ratio of at least 5:1, 7.5:1, or 10:1, and additionally or alternatively, step a) can be carried out with a maximum furan-to-catalyst weight ratio of 50:1, 40:1, or 25:1 or less. In general, the furan-to-catalyst weight ratio can be within the range from any minimum weight ratio to any maximum weight ratio disclosed herein. Thus, non-limiting ranges suitable for the furan-to-catalyst weight ratio may include 5:1 to 50:1, 5:1 to 25:1, 7.5:1 to 40:1, 7.5:1 to 25:1, 10:1 to 50:1, 10:1 to 40:1, or 10:1 to 25:1. Other ranges suitable for the furan-to-catalyst weight ratio in step a) are readily found in this disclosure.

[0056] In one embodiment, step a) may be carried out in a fixed-bed reactor. In such embodiments, the furan compound-catalyst contact time (or reaction time) can be expressed as the weight-time-space rate (WHSV), i.e., the ratio (in units of g / g / hr) of the weight of the furan compound reactant in contact with a given weight of the solid acid catalyst per unit time. Step a) may be carried out with a minimum WHSV value of 0.01, 0.05, 0.1, 0.15, or 0.2, and additionally or alternatively, step a) may be carried out with a maximum WHSV value of 10, 5, 4, 3, 2, or 1. In general, the WHSV of step a) may be within the range of any minimum WHSV to any maximum WHSV disclosed herein. Therefore, suitable non-limiting ranges for WHSV may include 0.01–10, 0.01–5, 0.05–4, 0.05–2, 0.1–10, 0.1–3, 0.15–4, 0.15–2, 0.2–3, or 0.2–1. Other suitable WHSV ranges are readily found in this disclosure.

[0057] In the fixed-bed reactor configuration, the conversion of the furan compound to the γ-dicarbonyl compound can be achieved by passing it through the fixed-bed reactor multiple times or by passing it through the fixed-bed reactor once. In the configuration in which the conversion of the furan compound to the γ-dicarbonyl compound is achieved by passing it through the fixed-bed reactor multiple times, the average single-pass conversion rate of the furan compound (or the average single-pass molar yield to the γ-dicarbonyl compound) may be at least 5 mol%, at least 10 mol%, at least 15 mol%, at least 20 mol%, or at least 25 mol%, and additionally or alternatively, the average single-pass conversion rate of the furan compound (or the average single-pass molar yield to the γ-dicarbonyl compound) may be 75 mol% or less, 60 mol% or less, 50 mol% or less, 40 mol% or less, or 30 mol% or less. Generally, the average single-pass conversion rate (or average single-pass molar yield to the γ-dicarbonyl compound) of a furan compound can range from any minimum average single-pass conversion rate (or minimum average single-pass molar yield to the γ-dicarbonyl compound) of any furan compound disclosed herein to any maximum average single-pass conversion rate (or maximum average single-pass molar yield to the γ-dicarbonyl compound) of any furan compound disclosed herein. Therefore, non-limiting ranges suitable for the average single-pass conversion rate (or average single-pass molar yield to the γ-dicarbonyl compound) of a furan compound may include 5 mol% to 75 mol%, 10 mol% to 60 mol%, 10 mol% to 50 mol%, 15 mol% to 40 mol%, 20 mol% to 40 mol%, or 10 mol% to 30 mol%. Other suitable ranges for the average single-pass conversion rate (or average single-pass molar yield to the γ-dicarbonyl compound) of a furan compound are readily found in this disclosure. Generally, molar yield is based on the moles of the furan compound.

[0058] Unexpectedly, step a), whether carried out in a stirred-tank reactor or a fixed-bed reactor, efficiently converts the furan compound to produce the γ-dicarbonyl compound in a higher yield than observed in similar reactions using different catalysts and / or without water. The total conversion rate of the furan compound in step a) (or total molar yield to the γ-dicarbonyl compound) can be at least 70 mol%, more often at least 80 mol%, at least 85 mol%, at least 90 mol%, at least 95 mol%, or at least 97 mol%. The total molar yield is based on the moles of the furan compound.

[0059] Unless otherwise indicated, the composition of the dicarbonyl product (or reaction mixture containing the dicarbonyl product) is disclosed in mol%. Disclosure of composition in mol% herein may also imply disclosure of the same composition in area% (area percentage determined using gas chromatography, as described herein), since the disclosed process and the resulting product are often analyzed or evaluated in this manner. Conversion rates of furan compounds may be available in area% or mol%; however, these conversion rates using area% and mol% are not identical. For example, a disclosure that a γ-dicarbonyl compound can be produced in a yield of at least 90 mol% may also imply a disclosure that a γ-dicarbonyl compound can be produced in a yield of at least 90 area%.

[0060] The process for producing the pyrrole compounds disclosed herein typically yields a reaction mixture after step a), comprising the desired γ-dicarbonyl compound, residual furan reactant, solid catalyst, water, and by-products. Often, it is desirable to isolate or separate at least a portion (and possibly all) of the γ-dicarbonyl compound from the reaction mixture after step a). This can be achieved using any suitable technique, including but not limited to extraction, filtration, evaporation, distillation, or a combination of two or more of these techniques.

[0061] Additionally or alternatively, the steps disclosed herein may further include, prior to step b), separating at least a portion (and possibly all) of the solid acid catalyst from the reaction mixture after step a) using any suitable technique or any technique disclosed herein, e.g., extraction, filtration, evaporation, distillation, or any combination thereof. For example, the solid acid catalyst can be separated from the reaction mixture and then used in the remaining reaction mixture in step b), or the γ-dicarbonyl compound isolated from the reaction mixture can be used in step b).

[0062] Synthesis of pyrrole compounds In step b), the γ-dicarbonyl compound (from step a), either in the reaction mixture or partially or completely separated therefrom, can be contacted with ammonia, an ammonium salt, or a combination thereof to form a reaction product mixture containing the pyrrole compound. The pyrrole compound may have, but is not limited to, the following formulas: [ka]

[0063] Pyrrole compounds are produced from furan compounds (e.g., furan compound (F1)) via γ-dicarbonyl compounds (e.g., γ-dicarbonyl compound (D1)). Therefore, R, R in formula (P1) 1 , R 2 , and R 3 This is the same as described herein for furan compounds (F1) and γ-dicarbonyl compounds (D1). Therefore, R, R 1 , R 2 , and R 3 This includes, independently, hydrogen atoms, and any C1-C12C2 30 Organyl group, or any C3-C group disclosed herein 60 It can be a silyl group. For example, R, R 1 , R 2 , and R 3 These are, independently, hydrogen atoms or C1~C 18It may be a hydrocarbyl group, or R and R 1 These are independent of C1~C 18 It can be a hydrocarbyl group, R 2 and R 3 It could be a hydrogen atom, or R and R 1 It can be a methyl group, R 2 and R 3 It could be a hydrogen atom.

[0064] In one embodiment, the pyrrole compounds prepared by the disclosed process include 2,5-dimethylpyrrole, 2,5-diethylpyrrole, 2-ethyl-5-methylpyrrole, 2-ethyl-5-n-propylpyrrole, 2,5-di-n-propylpyrrole, 2,5-diisopropylpyrrole, 2,5-di-n-butylpyrrole, 2,5-di-n-pentylpyrrole, 2,5-di-n-hexylpyrrole, 2,5-di-n-heptylpyrrole, and 2,5-di-n -Octylpyrrole, 2,3,5-triethylpyrrole, 2,3,5-tri-n-butylpyrrole, 2,3,5-tri-n-pentylpyrrole, 2,3,5-tri-n-hexylpyrrole, 2,3,5-tri-n-heptylpyrrole, 2,3,5-tri-n-octylpyrrole, 2,3,4,5-tetraethylpyrrole, 2,3,4,5-tetra-n-butylpyrrole, 2,3,4,5-tetra-n-hexylpyrrole, 2,5-dibenzylpyrrole This may include (or consist of, or consist of) any combination thereof, such as 2,4-dimethylpyrrole, 2-methyl-4-isopropylpyrrole, 2,4-dimethyl-3-ethylpyrrole, 2,4-diethylpyrrole, 2-ethyl-4-isopropylpyrrole, 2-methyl-4-sec-butylpyrrole, 2-ethyl-4-sec-butylpyrrole, 2-methyl-4-isobutylpyrrole, 2-ethyl-4-isobutylpyrrole, 2-methyl-4-t-butylpyrrole, 2-ethyl-4-t-butylpyrrole, 2-methyl-4-neopentylpyrrole, 2-ethyl-4-neopentylpyrrole, 3,4-dimethylpyrrole, 3,4-diethylpyrrole, 3,4-diisopropylpyrrole, 3,4-di-sec-butylpyrrole, 3,4-diisobutylpyrrole, 3,4-di-t-butylpyrrole, 3,4-di-neopentylpyrrole, etc. In certain embodiments consistent with the present invention, the pyrrole compound prepared by the disclosed steps may include (or consist of essentially) 2,5-dimethylpyrrole.

[0065] The γ-dicarbonyl compound (obtained from step a) or partially or completely separated therefrom may be contacted with ammonia and / or an ammonium salt to form a reaction product mixture containing the desired pyrrole compound in step b). In one embodiment, step b) may include contacting the γ-dicarbonyl compound with ammonia. In another embodiment, step b) may include contacting the γ-dicarbonyl compound with an ammonium salt. Non-limiting examples of suitable ammonium salts may include ammonium hydroxide (e.g., liquid ammonium hydroxide as an aqueous solution of ammonia), ammonium acetate, ammonium carbonate, ammonium bicarbonate, ammonium chloride, ammonium nitrate, ammonium phosphate, ammonium sulfate, and combinations thereof. Thus, step b) may include contacting the γ-dicarbonyl compound with ammonium hydroxide, or ammonium acetate, or ammonium carbonate, or ammonium bicarbonate, or ammonium chloride, or ammonium nitrate, or ammonium phosphate, or ammonium sulfate.

[0066] Step b) can be carried out at any suitable temperature. However, it can be carried out at a minimum temperature of 50°C, 60°C, 70°C, 80°C, or 90°C, and additionally or alternatively at a maximum temperature of 170°C, 160°C, 150°C, 140°C, or 130°C. Generally, the temperature in step b) can be within the range of any minimum to any maximum temperature disclosed herein. Therefore, non-limiting ranges suitable for the temperature in step b) and the formation of the pyrrole compound may include 50°C to 170°C, 60°C to 160°C, 70°C to 150°C, 80°C to 160°C, 80°C to 130°C, 90°C to 170°C, or 90°C to 140°C. Other suitable temperatures and temperature ranges are readily found in this disclosure. These temperature ranges also mean that the situation in which step b) (or the formation of the pyrrole compound) takes place at a series of different temperatures, rather than a single fixed temperature within each temperature range.

[0067] The duration of step b) is not particularly limited. Nevertheless, the minimum contact time (or reaction time) of step b) may be 15 minutes, 30 minutes, 1 hour, or 2 hours, and additionally or alternatively, the maximum contact time (or reaction time) may be 10 hours, 8 hours, 6 hours, 5 hours, or 4 hours. In general, the contact time (or reaction time) of step b) may be within the range of any minimum time to any maximum time disclosed herein. Thus, non-limiting ranges suitable for contact time (or reaction time) may include 15 minutes to 10 hours, 30 minutes to 8 hours, 30 minutes to 4 hours, 1 hour to 6 hours, 1 hour to 4 hours, 2 hours to 10 hours, 2 hours to 6 hours, or 2 hours to 5 hours. Other suitable ranges for the duration of step b) are readily found in this disclosure.

[0068] The reaction product mixture of step b) contains the desired pyrrole compound. However, in many cases the reaction product mixture may have two phases, comprising an organic phase and an aqueous phase. Since it may be advantageous to remove the aqueous phase from the reaction product mixture, the disclosed process may further include a step after process b) of separating at least some (and possibly all) of the water from the reaction product mixture (e.g., using phase cleavage).

[0069] Additionally or alternatively, the process for producing the pyrrole compounds disclosed herein may further include, after step b), a step of separating at least a portion of the pyrrole compounds from the reaction product mixture, or isolating at least a portion (and possibly all) of them. This can be achieved using any suitable technique, such as extraction, filtration, drying, evaporation, distillation, or any combination thereof.

[0070] Unexpectedly, the disclosed two-step synthesis efficiently converts the furan compound to the γ-dicarbonyl compound, and subsequently produces the pyrrole compound in remarkably high yield. For example, the molar yield for the pyrrole compound may be at least 60 mol%, more often at least 70 mol%, at least 80 mol%, at least 90 mol%, at least 95 mol%, or at least 97 mol%. The molar yield is based on the initial moles of the furan compound. Unless otherwise indicated, the compositional aspects of the pyrrole product (or reaction product mixture containing the pyrrole product) are disclosed in mol%. Any disclosure of a compositional aspect in mol% herein also implies a disclosure of the same compositional aspect in area% (area percentage measured using gas chromatography as described herein), since the numerical values ​​using area% and mol% are not identical, but the disclosed process and the resulting product are often analyzed or evaluated in this manner. A typical example is the disclosure that a pyrrole compound can be produced in a yield of at least 90 mol%, which also implies that the pyrrole compound can be produced in a yield of at least 90 area%.

[0071] solid acid catalyst In step a) of the process disclosed herein for producing a pyrrole compound, a furan compound, a solid acid catalyst, and water are brought into contact to form a reaction mixture containing a γ-dicarbonyl compound. Any suitable solid acid catalyst can be used. Exemplary and representative examples of suitable solid acid catalysts may include solid acid catalyst resins. Solid acid catalyst resins may include styrene-divinylbenzene resins, functionalized styrene-divinylbenzene resins, 4-vinylpyridinedivinylbenzene resins, functionalized 4-vinylpyridinedivinylbenzene resins, ionomer resins, tetrafluoroethylene polymer resins modified with sulfonic acid-terminated perfluorovinyl ether groups, or any combination thereof, or styrene-divinylbenzene resins, 4-vinylpyridinedivinylbenzene resins, ionomer resins, tetrafluoroethylene resins modified with sulfonic acid-terminated perfluorovinyl ether groups, etc., and combinations thereof. Some of these types of solid acid catalysts are available under the trade names Amberlyst® resin and Nafion® resin.

[0072] In one embodiment of the present invention, step a) comprises contacting a furan compound, a solid acid catalyst, and water to form a reaction mixture containing a γ-dicarbonyl compound, wherein the solid acid catalyst comprises a styrene-divinylbenzene resin. In another embodiment, step a) comprises contacting a furan compound, a solid acid catalyst, and water to form a reaction mixture containing a γ-dicarbonyl compound, wherein the solid acid catalyst comprises a 4-vinylpyridinedivinylbenzene resin. In yet another embodiment, step a) comprises contacting a furan compound, a solid acid catalyst, and water to form a reaction mixture containing a γ-dicarbonyl compound, wherein the solid acid catalyst comprises a tetrafluoroethylene resin modified with sulfonic acid group-terminated perfluorovinyl ether groups. [Examples]

[0073] The present invention will be further illustrated by the following embodiments, which should not be construed as limiting the scope of the invention. After reading this description, various other embodiments, modifications and equivalents will be obvious to those skilled in the art without departing from the spirit of the invention or the scope of the appended claims.

[0074] Gas chromatography (GC) analysis was performed using an HP-Innowax column (polyethylene glycol, capillary 30 m × 0.25 mm × 25 μm nominal) on an Agilent 7890 GC system. The column was held at 40°C for 2 minutes, then heated from 40°C to 220°C at a rate of 8°C / min, and then heated to 270°C at a rate of 15°C / min, where it was held for 15 minutes. The GC analysis column eluent was measured using a flame ionization detector. Reactants and products were identified and the reaction progress was monitored using 2,5-dimethylfuran (retention time approximately 3 minutes in Figures 1-3) and 2,5-hexanedione (retention time approximately 12.2-12.6 minutes, depending on the peak size in Figures 1-3) standards.

[0075] Examples 1-5 Synthesis of γ-dicarbonyl compound (2,5-hexanedione) from furan compound (2,5-dimethylfuran, DMF) All liquid raw materials were pressurized into the autoclave. If solids were used, they were added before closing the autoclave. The autoclave was then pressurized with nitrogen to 50 psig, and the pressure was released three times to remove air from the system. Approximately 50–75 psig of nitrogen was added to the autoclave, and then it was heated to the desired temperature. Under reaction conditions, the pressure was in the range of 90–140 psig. The reaction was monitored by GC until the conversion stopped. Some initial samples were biphasic. If a sample was biphasic, 2-propanol was added to the sample to homogenize it for GC analysis.

[0076] In Example 1, DMF was mixed with water and concentrated sulfuric acid, as summarized in Table I. The reaction was carried out at 100°C for 3 hours, followed by 140°C for 1 hour. Figure 1 is a GC plot of the reaction mixture in Example 1. The conversion rate of DMF was 93 area % (approximately 93 mol%, where the molar percentage value corresponds to the area percentage). While the conversion using sulfuric acid was acceptable, the presence of sulfuric acid before the reaction mixture containing 2,5-hexanedione is reacted with a base (e.g., ammonia or an ammonium salt) to form the subsequent pyrrole compound makes the separation process difficult.

[0077] In Example 2, DMF was mixed with water and methanesulfonic acid (>99%), as summarized in Table II. The reaction was carried out at 140°C for 3 hours. Figure 2 is the GC plot of the reaction mixture in Example 2. The conversion rate of DMF was 95.7 area% (approximately 95.7 mol%). Note the numerous components within the 15-25 minute range on the GC curve. As in Example 1, the presence of residual methanesulfonic acid before the reaction mixture containing 2,5-hexanedione is reacted with a base (e.g., ammonia or an ammonium salt) to form the subsequent pyrrole compound makes the separation step difficult.

[0078] In Example 3, DMF was mixed with water and Amberlyst 36 (styrene-divinylbenzene solid acid catalyst resin) as summarized in Table III. After the final nitrogen purge cycle, 75 psig of nitrogen was added and the reactor contents were heated to 145°C. The reaction was sampled every hour to monitor its progress and was considered complete after 4 hours. The pressure ranged from 125 to 140 psig. Figure 3 is a GC plot of the reaction mixture in Example 3. Unexpectedly, the reaction mixture contained approximately 3 area% (mol%) of 2,5-dimethylfuran and 97 area% (mol%) of 2,5-hexanedione. The DMF conversion rate was 97 area% (mol%).

[0079] In Example 4, the reaction mixture from Example 3 was further processed to isolate 2,5-hexanedione. Water was removed from the reactor, and residual water was removed from the crude reaction mixture using a rotary evaporator. The conditions used to remove the water were a 70°C water bath with the pressure reduced to less than 100 torr. After this step, 267.5 g of the crude product remained in the kettle.

[0080] Next, the crude product was vacuum distilled to obtain the pure overhead product. The flask was heated to 80°C at 400 torr to remove any remaining light components. Finally, the temperature was increased to 120°C and the pressure was reduced to 50 torr to obtain a high-purity overhead 2,5-hexanedione product (GC purity of approximately 98% area). A reflux ratio of 5:5 was used throughout. This distillation took approximately 25 hours over several days to complete.

[0081] Approximately 221 g of high-purity overhead product was collected (yield 72 area%). However, the final kettle (42.5 g), although GC showed a purity of 98 area%, was slightly darker in color and could not be further distilled due to the liquid level in the flask. If this material had also been recovered, the overall yield of 2,5-hexanedione would have been 86 area% (approximately 86 mol%). Beneficially, 2,5-hexanedione was found to be very easy to separate from the reaction mixture of Example 3 in pure form.

[0082] In Example 5, as summarized in Table IV, DMF was mixed with water and Amberlyst 15 (solid acid catalyst; styrenedivinylbenzene). After the final nitrogen purge cycle, 50 psig of nitrogen was added and the reactor contents were heated to 110°C. The reaction was sampled every hour to monitor its progress, and was considered complete after 20 hours. Similar to Example 3, the DMF conversion rate was 97 area% (mol%).

[0083] Compared to sulfuric acid and methanesulfonic acid (Examples 1-2), the use of a solid acid catalyst offers further advantages in addition to the high conversion rate of DMF. With sulfuric acid and methanesulfonic acid, further removal steps are required, such as extraction using a base or salt formation with ammonia. Extraction requires additional solvents. Furthermore, if the acid is present during water removal, such as in the step of isolating 2,5-hexanedione, a reverse reaction can occur, reforming the DMF. In contrast, when a solid acid catalyst is used, this problem is not an issue because the solid catalyst can be easily filtered before water removal.

[0084] Configuration Example 6 Constitutive synthesis of pyrrole compounds (2,5-dimethylpyrrole) from γ-dicarbonyl compounds (2,5-hexanedione) 2,5-Hexanedione (142 g, approximately 90% purity) can be charged into a 250 mL round-bottom flask equipped with a star bar, heating mantle, reflux condenser, and nitrogen inlet / outlet. The reaction flask is heated to 60°C, and ammonium carbonate (150 g) is added over 90 minutes. Gas generation becomes apparent during this heating stage. Once gas generation stops, the temperature is raised to 80°C over 30 minutes. After cooling to room temperature, the two-phase reaction mixture is separated using a separatory funnel. The aqueous phase generated during the reaction is separated from the organic phase, and the organic phase is washed with an additional 125 mL of water. A total of 90 g of 2,5-dimethylpyrrole (85% molar yield relative to dione) is collected with a purity of 96 area% (approximately 96 mol%) as determined by GC analysis.

[0085] [Table 1] [Table 2] [Table 3] [Table 4]

[0086] The present invention has been described above with reference to numerous embodiments and specific examples. In light of the detailed description above, many modifications will be obvious to those skilled in the art. All such obvious modifications are within the scope intended by the appended claims. Other embodiments of the present invention include, but are not limited to, the following (embodiments are described as including, or essentially consisting of, or consisting of):

[0087] Embodiment 1. A process for producing a pyrrole compound, a) A reaction mixture containing a γ-dicarbonyl compound is formed by contacting a furan compound, a solid acid catalyst, and water. b) The step comprising contacting the γ-dicarbonyl compound with ammonia, an ammonium salt, or a combination thereof to form a reaction product mixture containing the pyrrole compound.

[0088] Embodiment 2. The furan compound (F1), the γ-dicarbonyl compound (D1), and the pyrrole compound (P1) have the following formula: [ka] In the formula, R, R 1 , R 2 , and R 3 These independently form hydrogen atoms, C1~C 30 organyl group, or C3~C 60 The process according to embodiment 1, wherein the group is a silyl group.

[0089] Appearance 3. R, R 1 , R 2 and R 3 The step according to embodiment 2, wherein at least one of the atoms is not a hydrogen atom.

[0090] Appearance 4.R, R 1 , R 2 , and R 3 These independently represent hydrogen atoms or C1~C 18The step according to embodiment 2 or embodiment 3, wherein the group is a hydrocarbyl group.

[0091] Appearance 5. R and R 1 They become independent, C1~C 18 It is a hydrocarbyl group, R 2 and R 3 The method according to embodiment 2 or 3, wherein is a hydrogen atom.

[0092] Appearance 6. R and R 1 The step according to any one of embodiments 2 to 5, wherein is independently a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, a t-butyl group, a phenyl group, a benzyl group, a tolyl group, or a xylyl group.

[0093] Appearance 7. R and R 1 is a methyl group, R 2 and R 3 The process according to any one of embodiments 2 to 6, wherein the substance is hydrogen.

[0094] Embodiment 8. The pyrrole compound is 2,5-dimethylpyrrole, 2-methyl-5-ethylpyrrole, 2,5-diethylpyrrole, 2-ethyl-5-methylpyrrole, 2-ethyl-5-n-propylpyrrole, 2,5-di-n-propylpyrrole, 2,5-diisopropylpyrrole, 2,5-di-n-butylpyrrole, 2,5-di-n-pentylpyrrole, 2,5-di-n-hexylpyrrole, 2,5-di-n-heptylpyrrole, 2 ,5-di-n-octylpyrrole, 2,3,5-triethylpyrrole, 2,3,5-tri-n-butylpyrrole, 2,3,5-tri-n-pentylpyrrole, 2,3,5-tri-n-hexylpyrrole, 2,3,5-tri-n-heptylpyrrole, 2,3,5-tri-n-octylpyrrole, 2,3,4,5-tetraethylpyrrole, 2,3,4,5-tetra-n-butylpyrrole, 2,3,4,5-tetra-n-hexylpyrrole The step according to embodiment 1, which may include 2,5-dibenzyl pyrrole, 2,4-dimethylpyrrole, 2-methyl-4-isopropylpyrrole, 2,4-dimethyl-3-ethylpyrrole, 2,4-diethylpyrrole, 2-ethyl-4-isopropylpyrrole, 2-methyl-4-sec-butylpyrrole, 2-ethyl-4-sec-butylpyrrole, 2-methyl-4-isobutylpyrrole, 2-ethyl-4-isobutylpyrrole, 2-methyl-4-t-butylpyrrole, 2-ethyl-4-t-butylpyrrole, 2-methyl-4-neopentylpyrrole, 2-ethyl-4-neopentylpyrrole, 3,4-dimethylpyrrole, 3,4-diethylpyrrole, 3,4-diisopropylpyrrole, 3,4-di-sec-butylpyrrole, 3,4-diisobutylpyrrole, 3,4-di-t-butylpyrrole, 3,4-di-neopentylpyrrole, or any combination thereof.

[0095] Embodiment 9. The process according to Embodiment 1, wherein the pyrrole compound comprises 2,5-dimethylpyrrole.

[0096] Embodiment 10. The process according to any one of Embodiments 1 to 9, wherein the solid acid catalyst comprises a styrene-divinylbenzene resin, a 4-vinylpyridinedivinylbenzene resin, an ionomer resin, a tetrafluoroethylene resin modified with a sulfonic acid group-terminated perfluorovinyl ether group, or any combination thereof.

[0097] Embodiment 11. The process according to any one of Embodiments 1 to 9, wherein the solid acid catalyst comprises a styrene-divinylbenzene resin.

[0098] Embodiment 12. The process according to any one of Embodiments 1 to 9, wherein the solid acid catalyst comprises a 4-vinylpyridinedivinylbenzene resin.

[0099] Embodiment 13. The process according to any one of Embodiments 1 to 9, wherein the solid acid catalyst comprises a tetrafluoroethylene resin modified with sulfonic acid group-terminated perfluorovinyl ether groups.

[0100] Embodiment 14. Step b) is the step according to any one of Embodiments 1 to 13, comprising contacting the γ-dicarbonyl compound with ammonia.

[0101] Embodiment 15. Step b) is the step according to any one of Embodiments 1 to 13, comprising contacting the γ-dicarbonyl compound with the ammonium salt (for example, ammonium hydroxide, ammonium acetate, ammonium carbonate, ammonium bicarbonate, ammonium chloride, ammonium nitrate, ammonium phosphate, ammonium sulfate, or any combination thereof).

[0102] Embodiment 16. Step a) is the step according to any one of Embodiments 1 to 15, wherein step a) is performed in any molar ratio of water to the furan compound described herein (for example, among the molar ratios of water to the furan compound otherwise disclosed, in the range of 0.5:1 to 10:1, 1:1 to 7.5:1, or 1.5:1 to 5:1).

[0103] Embodiment 17. Step a) is the step according to any one of Embodiments 1 to 16, performed at any temperature below the maximum operating temperature of the solid acid catalyst.

[0104] Embodiment 18. Step a) is the step according to any one of Embodiments 1 to 17, performed at any temperature disclosed herein (for example, in the range of 80°C to 180°C, 100°C to 155°C, or 120°C to 150°C among other disclosed temperatures).

[0105] Embodiment 19. Step a) is the step according to any one of Embodiments 1 to 18, wherein step a) is performed at a pressure sufficient to maintain the water in the liquid phase.

[0106] Embodiment 20. Step a) is the step according to any one of Embodiments 1 to 19, performed at any pressure disclosed herein (for example, in the range of 25 to 150 psig or 50 to 125 psig among other disclosed pressures).

[0107] Embodiment 21. Step a) is the process described in any one of Embodiments 1 to 20, carried out in a stirred-tank reactor or a fixed-bed reactor.

[0108] Embodiment 22. Step a) is the step according to any one of Embodiments 1 to 21, carried out in a stirred tank reactor for any of the times disclosed herein (for example, 10 minutes to 8 hours or 1 hour to 5 hours among the other disclosed times).

[0109] Embodiment 23. Step a) is the step according to Embodiment 21 or 22, carried out in a stirred tank reactor in any weight ratio of the furan compound disclosed herein to the solid acid catalyst (for example, among other weight ratios of the disclosed furan compound to the solid acid catalyst, in the range of 5:1 to 50:1, 7.5:1 to 40:1, or 10:1 to 25:1).

[0110] Embodiment 24. The step according to any one of Embodiments 21 to 23, wherein step a) is carried out in a stirred-tank reactor, and the conversion rate of the furan compound (or yield to the γ-dicarbonyl compound) is any molar conversion rate (or molar yield) disclosed herein (e.g., at least 70%, at least 80%, at least 90%, at least 95%, or at least 97%).

[0111] Embodiment 25. The step according to Embodiment 21, wherein step a) is carried out in a fixed-bed reactor with any furan compound WHSV disclosed herein (for example, in the range of 0.01 to 5, 0.05 to 4, 0.1 to 3, 0.15 to 2, or 0.2 to 1 among the disclosed furan compounds WHSV).

[0112] Embodiment 26. The step according to Embodiment 21 or 25, wherein step a) is carried out in a fixed-bed reactor, and the single-pass conversion rate of the furan compound (or single-pass yield to the γ-dicarbonyl compound) is any single-pass molar conversion rate (or single-pass molar yield) disclosed herein (e.g., at least 10%, at least 25%, at least 50%, at least 75%, or at least 90%).

[0113] Embodiment 27. The step according to any one of Embodiments 1 to 26, further comprising the step of separating at least a portion (and possibly all) of the γ-dicarbonyl compound from the reaction mixture using any suitable technique or any technique disclosed herein, such as extraction, filtration, evaporation, distillation, etc., or any combination thereof, prior to step b).

[0114] Embodiment 28. The step according to any one of Embodiments 1 to 27, further comprising the step of separating at least a portion (and possibly all) of the solid acid catalyst from the reaction mixture using any suitable technique or any technique disclosed herein, for example, extraction, filtration, evaporation, distillation, or any combination thereof, prior to step b).

[0115] Embodiment 29. Step b) is the step according to any one of Embodiments 1 to 28, performed at any temperature disclosed herein (for example, in the range of 70°C to 150°C or 80°C to 130°C among other disclosed temperatures).

[0116] Embodiment 30. Step b) is the step according to any one of Embodiments 1 to 29, performed over any time disclosed herein (for example, 30 minutes to 8 hours or 2 hours to 5 hours among other disclosed times).

[0117] Embodiment 31. The process according to any one of Embodiments 1 to 30, wherein the reaction product mixture comprises an organic phase and an aqueous phase.

[0118] Embodiment 32. The process according to any one of Embodiments 1 to 31, further comprising the step of separating at least a portion (and possibly all) of the water from the reaction product mixture after step b) (e.g., phase cleavage).

[0119] Embodiment 33. The step according to any one of Embodiments 1 to 32, further comprising, after step b), a step of separating at least a portion (and possibly all) of the pyrrole compound from the reaction product mixture using any suitable technique or any technique disclosed herein, such as extraction, filtration, drying, evaporation, distillation, etc., or any combination thereof.

[0120] Embodiment 34. The process according to any one of Embodiments 1 to 33, wherein the pyrrole compound is produced in any molar yield disclosed herein (for example, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, or at least 97% based on the furan compound).

Claims

1. A process for producing pyrrole compounds, a) Forming a reaction mixture containing a γ-dicarbonyl compound by contacting a furan compound, a solid acid catalyst, and water, wherein the molar ratio of water to the furan compound is in the range of 0.5:1 to 10:1, and the formation of the reaction mixture. b) The γ-dicarbonyl compound is brought into contact with ammonia, an ammonium salt, or a combination thereof to form a reaction product mixture containing the pyrrole compound, The solid acid catalyst is a styrene-divinylbenzene resin. The pyrrole compound is 2,5-dialkylpyrrole, The furan compound is 2,5-dialkylfuran, in the above step.

2. The furan compound (F1) and the γ-dicarbonyl compound (D1) have the following formulas: 【Chemistry 1】 In the above formula, R and R １ C １ ~C ３０ It is an alkyl group, R ２ and R ３ The step according to claim 1, wherein is a hydrogen atom.

3. In the above formula, R and R １ C １ ~C １８ The step according to claim 2, wherein the alkyl group is such that R2 and R3 are hydrogen atoms.

4. The step according to claim 2, wherein R and R1 are independently methyl groups.

5. Step a) is, A temperature below the maximum operating temperature of the solid acid catalyst, and The step according to claim 1, carried out at a pressure sufficient to maintain the water in a liquid phase.

6. Step a) is, Temperatures in the range of 80°C to 180°C, and The process according to claim 1, carried out at a pressure in the range of 25 to 150 psig.

7. The step according to claim 1, wherein the molar ratio of water to the furan compound is in the range of 1:1 to 7.5:

1.

8. The step according to claim 1, wherein step a) is carried out in a stirred tank reactor in a weight ratio of the furan compound to the solid acid catalyst in the range of 5:1 to 50:

1.

9. The step according to claim 1, wherein the conversion rate of the furan compound is at least 90 mol%.

10. The step according to claim 9, wherein the yield to the γ-dicarbonyl compound is at least 80 mol%.

11. The step according to claim 1, wherein step a) is carried out in a fixed-bed reactor with a furan compound WHSV in the range of 0.01 to 5.

12. The process according to claim 1, Prior to step b), a step of separating at least a portion of the γ-dicarbonyl compound from the reaction mixture, and / or The step further comprises, prior to step b), separating at least a portion of the solid acid catalyst from the reaction mixture.

13. The step according to claim 1, wherein step b) comprises contacting the γ-dicarbonyl compound with the ammonium salt, the ammonium salt being ammonium hydroxide, ammonium acetate, ammonium carbonate, ammonium bicarbonate, ammonium chloride, ammonium nitrate, ammonium phosphate, ammonium sulfate, or any combination thereof.

14. The process according to claim 1, The reaction product mixture comprises an organic phase and an aqueous phase. The step further comprising, after step b), separating at least a portion of the water from the reaction product mixture.

15. The step according to claim 1, wherein the pyrrole compound is produced in a yield of at least 70 mol% based on the furan compound.

16. The step according to claim 1, further comprising the step of separating at least a portion of the pyrrole compound from the reaction product mixture after step b).

17. The process according to claim 1, wherein step a) is performed at a temperature in the range of 110°C to 170°C.

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