Co-feeding ethylene with allyl alcohol in hydroformylation to produce 1,4-butanediol and n-propanol

Abstract

A process for co-feeding gaseous ethylene and liquid allyl alcohol in the presence of a catalyst to produce 1,4-butanediol and n-propanol may comprise: introducing a gaseous mixture of ethylene, carbon monoxide, and hydrogen in a solvent into a reactor in the presence of a hydroformylation catalyst; introducing liquid allyl alcohol (AA) into the reactor; and conducting a hydroformylation reaction at a temperature between 50° C. and 100° C. to obtain a hydroformylation product.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 083,615, filed on September 25, 2020, which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates to a method for producing 1,4-butanediol (BDO) and its branched byproduct 2-methyl-1,3-propanediol by co-feeding gaseous ethylene with liquid allyl alcohol in a hydroformylation process. The present invention relates to a process for producing n-propanol (n-Pr) and more particularly to a process for producing n-propanol and BDO by co-feeding gaseous ethylene with liquid allyl alcohol in the presence of a hydroformylation catalyst in a homogeneous reaction. Background Art

[0004] Typically, 1,4-butanediol (BDO) is produced using propylene oxide (PO) as a starting material. PO is first isomerized to allyl alcohol (AA), which is then hydroformylated with synthesis gas (H2 + CO) to produce 4-hydroxybutyraldehyde (HBA), which is then hydrogenated to 1,4-butanediol. See, for example, U.S. Patent No. 4,215,077.

[0005] Hydroformylation is a process in which olefins are reacted with carbon monoxide and hydrogen to form aldehydes. This process is used in the chemical industry to produce compounds such as propionaldehyde and butyraldehyde from simple olefins such as ethylene and propylene.

[0006] In the hydroformylation of ethylene, the propionaldehyde (PA) product is distilled from the catalyst solution prior to hydrogenation to produce n-propanol, see, for example, U.S. Patent No. 4,262,142. Typical hydroformylation processes involve catalysts such as Rh-phosphite complexes and require high process temperatures ranging from 100°C to 145°C. High temperatures increase production costs.

[0007] Another process is the hydroformylation of activated olefins such as allyl alcohol to produce hydroxy aldehydes, including 4-hydroxybutyraldehyde and 3-hydroxy-2-methylpropional (HMPA). In this process, the hydroxy aldehydes in the toluene catalyst solution are extracted with water before hydrogenation with a sponge nickel catalyst. The remaining catalyst solution is then recycled back into the hydroformylation process.

[0008] The hydroformylation mechanisms differ for gaseous feedstocks such as ethylene and liquids such as allyl alcohol. Process control to combine the two hydroformylation reactions while maintaining a linear to branched ratio and effectively separating the products from the recycle catalyst solution can be difficult. Therefore, there remains a need for efficient production of 1,4-butanediol and n-propanol while maintaining a high linear to branched C4-diol ratio and efficiently recycling the catalyst. Summary of the Invention

[0009] The present disclosure provides a process for producing propanol and, in addition, 1,4-butanediol and 2-methyl-1,3-propanediol. The disclosed process involves co-feeding gaseous ethylene with liquid allyl alcohol, along with carbon monoxide and hydrogen, in the presence of a solvent and a hydroformylation catalyst to produce linear 4-hydroxybutyraldehyde, the branched isomer 3-hydroxy-2-methyl-propanal, and propanal. The hydroformylation catalyst comprises a rhodium phosphine complex. After completion of the hydroformylation, the reaction product is subjected to water extraction to separate HBA / HMPA / PA from the hydroformylation catalyst / solvent, wherein the catalyst / solvent is recycled back to the hydroformylation reaction. The aqueous aldehyde solution is then hydrogenated in the presence of a nickel catalyst, wherein HBA and HMPA are converted to BDO and PA, respectively. Propionaldehyde is converted into n-propanol.

[0010] Maintaining a linear (HBA) to branched (HMPA) ratio of 10:1 or higher increases the yield of PA, making it suitable for further processing. The significantly lower reaction temperature (approximately 65°C) saves energy compared to reaction temperatures between 100°C and 145°C. Potential savings are also realized in terms of conserving phosphine ligands, which degrade more as reaction temperatures rise above 110°C.

[0011] According to one aspect of the present disclosure, the molar ratio of ethylene to allyl alcohol is 1:3 to 1:7. In one embodiment, the molar ratio of ethylene to allyl alcohol is in the range of 1:4 to 1:5.

[0012] According to one aspect of the present disclosure, the amount of allyl alcohol used in the hydroformylation reaction is 5 wt % to 40 wt % in the solvent.

[0013] According to one aspect of the present disclosure, the molar ratio of ethylene:carbon monoxide:hydrogen is (0.18-0.35):(2.7-4.1):(5-7). In one embodiment, the molar ratio of ethylene:carbon monoxide:hydrogen is about 1:13:22.

[0014] According to one aspect of the present disclosure, the gaseous mixture is introduced at an elevated pressure within a range of about 137.9 kPa to about 1378.95 kPa. In one embodiment, the gaseous mixture is introduced at a pressure within a range of about 689.48 kPa to about 1034.21 kPa. In one embodiment, the gaseous mixture is introduced at a pressure within a range of about 896.32 kPa to about 965.27 kPa.

[0015] According to one aspect of the present disclosure, the hydroformylation catalyst is a mixture of rhodium and a ligand selected from the group consisting of trans-1,2-bis(3,5-trimethylphenylphosphinomethyl)cyclobutane (ligand A), 1,4-bis(diphenylphosphinobutane) (DPPB), triphenylphosphine (TPP), bidentate diphosphates, and combinations thereof.

[0016] According to one aspect of the present disclosure, the molar ratio of rhodium to ligand A is in the range of 1:1 to 1:5, or the molar ratio of rhodium to ligand A is about 1:2.

[0017] According to one aspect of the present disclosure, the hydroformylation catalyst is a mixture of rhodium, ligand A, DPPB, and TPP, or a molar ratio of rhodium:ligand A:DPPB:TPP of about 1:2:0.1:2. According to one aspect of the present disclosure, the molar ratio of rhodium:ligand A:DPPB:TPP can be in the range of about 0.8-1.2:1.6-2.4:0.08-0.12:1.6-2.4, wherein each value within the indicated ranges can be independently selected.

[0018] According to one aspect of the present disclosure, rhodium is present in an amount from 50 ppm to 500 ppm.

[0019] According to one aspect of the present disclosure, the reaction temperature is maintained between 50°C and 100°C, or the reaction temperature is maintained between 60°C and 80°C.

[0020] According to one aspect of the present disclosure, the water to feed ratio in the water extraction process is in the range of 1:5 to 2:1. According to one aspect of the present disclosure, the water to feed ratio in the water extraction process is in the range of 1.5:4 to 1.5:1. According to one aspect of the present disclosure, the water to feed ratio in the water extraction process is in the range of 3:5 to 1:1. According to one aspect of the present disclosure, the water to feed ratio in the water extraction process is in the range of 1:1 to 2:1. According to one aspect of the present disclosure, the water to feed ratio in the water extraction process is in the range of 1:5 to 1:1. According to one aspect of the present disclosure, the water to feed ratio in the water extraction process is in the range of 1:3 to 1:1.

[0021] As used herein, the term "inert solvent" refers to a solvent that is stable under the reaction conditions without decomposing or forming impurities.

[0022] As used herein, "hydroformylation" refers to the reaction in which a formyl group (CHO) and a hydrogen atom are added to the carbon-carbon double bond of an olefin to produce an aldehyde.

[0023] As used herein, "hydroformylation catalyst" refers to a catalyst system that promotes the hydroformylation reaction at relatively low temperatures.

[0024] Unless the context dictates otherwise, the use of the words "a" or "an" when used in conjunction with the term "comprising" in a claim or specification means one or more than one.

[0025] The term "about" refers to the stated value plus or minus the margin of error in the measurement, or plus or minus 10% if no measurement is specified.

[0026] The term "or" as used in the claims is intended to mean "and / or" unless explicitly stated to refer to only alternatives or the alternatives are mutually exclusive.

[0027] The terms "comprise," "have," "include," and "contain" (and variations thereof) are open-ended linking verbs and allow for the addition of additional elements when used in a claim.

[0028] The phrase "consisting of is closed and excludes all additional elements.

[0029] The phrase "consisting essentially of excludes additional material elements but allows for the inclusion of non-material elements that do not substantially change the nature of the disclosure.

[0030] The following abbreviations are used in this article:

[0031] BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A synthetic strategy for hydroformylation followed by hydrogenation to produce propanol from a co-feed of ethylene and allyl alcohol is provided.

[0033] Figure 2 The hydroformylation and hydrogenation of allyl alcohol and ethylene are shown.

[0034] Figure 3A A graph of synthesis gas consumption in the hydroformylation of allyl alcohol is provided.

[0035] Figure 3B A graph of syngas and ethylene consumption in ethylene hydroformylation is provided.

[0036] Figure 4 A graph of the syngas and ethylene consumption in the hydroformylation of allyl alcohol and ethylene is provided. DETAILED DESCRIPTION

[0037] The present disclosure provides a novel process for co-feeding a gaseous mixture of ethylene, carbon monoxide, and hydrogen with liquid allyl alcohol for hydroformylation in a solvent in the presence of a hydroformylation catalyst. The resulting product can be separated from the catalyst / solvent for further processing, such as hydrogenation, to ultimately produce 1,4-butanediol and n-propanol.

[0038] Although hydroformylation of allyl alcohol is typically performed to produce 4-hydroxybutyraldehyde, followed by hydrogenation to produce 1,4-butanediol, the co-feeding of gaseous ethylene with allyl alcohol provides a pathway for producing additional products such as propionaldehyde. However, separating the aldehyde product from the hydroformylation catalyst solution is technically challenging. While the hydroxyaldehyde (product of the hydroformylation of allyl alcohol) is efficiently extracted in water, the propionaldehyde produced by the ethylene hydroformylation is collected from the hydroformylation catalyst solution by distillation. See, for example, US 9,795,952. The temperature of such distillation can be as high as 150°C, at which temperature decomposition of the phosphine or phosphite ligands can occur, thereby degrading the hydroformylation catalyst.

[0039] Figure 1 Overview of the process flow. Figure 1 In the process flow outlined in

[0015] , a gaseous feed comprising ethylene, carbon monoxide and hydrogen is introduced into a reactor together with a liquid feed of allyl alcohol to carry out hydroformylation. The process is a homogeneous reaction of gaseous and liquid substrates, and the gaseous feed is mixed with the liquid feed to produce the product more uniformly. The reactor also contains a hydroformylation catalyst, and in one embodiment, the hydroformylation catalyst is present in a solvent (such as toluene). The product may include HBA, HMPA and PA.

[0040] After the hydroformylation reaction is complete, the product, along with the hydroformylation catalyst / solvent, is first subjected to water extraction to separate the product from the catalyst / solvent, and the catalyst / solvent can then be recycled back to the hydroformylation reactor. The separated products, HBA, HMPA, and PA, in water are moved to a hydrogenation reactor and hydrogenated in the presence of a sponge nickel catalyst.

[0041] The hydrogenation reaction converts HBA, HMPA and PA into BDO, The product was further purified to remove water and impurities.

[0042] The chemical synthesis pathway is shown in Figure 2 Reference Figure 2 In particular, the hydroformylation of allyl alcohol produces two different isomers, linear 4-hydroxybutyraldehyde and branched 3-hydroxy-2-methylpropanal. Each isomer will form a diol after hydrogenation, and the branched isomer is a lower value product, and its production can be minimized.

[0043] In the presence of a hydroformylation catalyst, the starting materials are allyl alcohol and ethylene, as well as carbon monoxide and hydrogen. Allyl alcohol itself is converted into linear 4-hydroxybutyraldehyde and branched 3-hydroxy-2-methylpropanal (as by-products), while a side reaction isomerizes allyl alcohol to propionaldehyde. Another possible route to allyl alcohol is direct hydrogenation to form n-propanol.

[0044] On the other hand, gaseous ethylene is hydroformylated in the presence of the same hydroformylation catalyst to produce only propionaldehyde.

[0045] Various hydroformylation catalyst systems can be used for hydroformylation reactions. Some such hydroformylation catalysts and processes use rhodium complexes in conjunction with ligands, such as phosphine ligands. In these embodiments, the hydroformylation catalyst system comprises a rhodium complex and a phosphine ligand. Such phosphine ligands comprise trisubstituted phosphines, such as triphenylphosphine. In embodiments, the phosphine ligands may comprise one or more selected from diphosphine ligands, monophosphines, and combinations thereof.

[0046] In these embodiments, the hydroformylation catalyst system includes a rhodium complex and a diphosphine ligand, such as trans-1,2-bis(bis(3,5-di-n-alkylphenyl)phosphinomethyl)cyclobutane, as described, for example, in U.S. Patent Nos. 7,294,602 and 7,279,606. In these embodiments, the diphosphine ligand includes trans-1,2-bis(bis(3,5-dimethylphenyl)phosphinomethyl)cyclobutane (also known as trans-1,2-bis[di(3,5-dimethylphenyl)phosphinomethyl]cyclobutane). trans-1,2-bis(bis(3,5-di-n-alkylphenyl)phosphinomethyl)cyclobutane has the following chemical structure:

[0047]

[0048] wherein R is an n-alkyl group. In embodiments, R is a methyl group, an ethyl group, or a propyl group. In embodiments, the bisphosphine ligand may be trans-1,2-bis(bis(3,5-dimethylphenyl)phosphinomethyl)cyclobutane or trans-1,2-bis(bis(3,5-diethyl-phenyl)phosphinomethyl)cyclobutane, 2,3-O-isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane (DIOP), R,R-xylyl DIOP, trans-1,2-bis(3,4,5-trimethylphenylphosphinomethyl)cyclobutane, or (-)-2,3-O-isopropylidene-2,3-dihydroxy-1,4-bis(3,5-dimethyldiphenylphosphino)butane. trans-1,2-bis(bis(3,5-di-n-alkylphenyl)phosphinomethyl)cyclobutane may be prepared by any suitable method. For example, it can be prepared by the reaction of trans-1,2-cyclobutane dimethanol, bis(toluenesulfonate) and lithium bis(3,5-di-n-alkylphenyl)phosphine. The ligands and catalyst compositions described herein are commercially available or can be prepared according to the methods, procedures, and processes described in patents and other literature, including U.S. Patent Nos. 7,271,295, 7,279,606, and WO2008 / 121194, each of which is incorporated herein by reference in its entirety for all purposes.

[0049] In certain embodiments, the hydroformylation catalyst system further includes a rhodium complex. This rhodium complex contains rhodium attached to a ligand group. In embodiments, the rhodium complex is soluble in a solvent. There are no particular restrictions on the choice of ligand attached to the rhodium complex. For example, such ligands include hydrides, carbonyls, substituted and unsubstituted cyclopentadienyls, 2,4-alkanediones, trialkyl or triaryl phosphines, diphosphines, and mixtures thereof. In embodiments, the ligand attached to the rhodium complex is selected from carbonyls, acetylacetonates (2,4-pentanedionato), triphenylphosphine, and mixtures thereof. Examples of rhodium complexes include, but are not limited to, (acetylacetonato)dicarbonylrhodium(I) (also known as dicarbonyl-acetylacetonato-rhodium(I), 2,4-pentanedionatodicarbonylrhodium(I), Rh(CO)2(acac), and dicarbonylacetylacetonatorhodium(I)) and tris(triphenylphosphine)carbonylrhodium hydride.

[0050] The rhodium complex can be pre-associated with a phosphine (e.g., trans-1,2-bis(bis(3,5-di-n-alkylphenyl)phosphinomethyl)cyclobutane) prior to use in the hydroformylation reaction, such that the [bis(bis(3,5-di-n-alkylphenyl)phosphinomethyl)cyclobutane] ligand forms part of the rhodium complex, or it can be added separately. However, in certain embodiments, the rhodium complex is added separately from the phosphine ligand (e.g., trans-1,2-bis(bis(3,5-di-n-alkylphenyl)phosphinomethyl)cyclobutane). In certain embodiments, the molar ratio of the phosphine ligand:rhodium complex (e.g., trans-1,2-bis(bis(3,5-di-n-alkylphenyl)phosphinomethyl)cyclobutane:rhodium complex) can be in the range of 0.5:1 to 5:1.

[0051] In an embodiment, the hydroformylation catalyst system comprises a rhodium complex and one or more diphosphine ligands, the rhodium complex comprises Rh(CO)2(acac), and the molar ratio of Rh(CO)2(acac) to diphosphine ligand is in the range of 0.1:1 to 1:5, 0.9:1.5 to 1:3, or 1:1.9 to 1:2.1.

[0052] In certain embodiments, the hydroformylation catalyst system may further comprise an ancillary ligand such that the hydroformylation is further carried out in the presence of the ancillary ligand added to the catalyst solution. In certain embodiments, the ancillary ligand comprises a monophosphine.

[0053] In certain embodiments, the monophosphine compound is a ligand in addition to any phosphine ligand that may be associated with the rhodium complex. In certain embodiments, the monophosphine compound may be a trisubstituted phosphine represented by the formula:

[0054] (R 1 )3P,

[0055] where R 1 is an alkyl or aryl group. 1 The aromatic R 1 The group comprises phenyl, tolyl and / or naphthyl. 1 The groups can be the same or different. In some embodiments, the monophosphine is a trisubstituted arylphosphine. In other embodiments, the monophosphine can be triphenylphosphine. In other embodiments, the monophosphine is triphenylphosphine.

[0056] In certain embodiments, the hydroformylation catalyst system includes a diphosphine ligand and a monophosphine, and the monophosphine is present such that the ratio of diphosphine to monophosphine is in a range of 1:1 to 1:3, 1:1.2 to 1:2, or 1:1.4 to 1:1.6.

[0057] Hydroformylation can be carried out in the presence of a hydroformylation reaction solvent. Typical solvents are those solvents that can dissolve the rhodium complex and are not reactive with the aldol produced in the hydroformylation step. The solvent can include an organic solvent with very low or minimum solubility in water. In certain embodiments, the hydroformylation reaction solvent is selected from C5-C20 aliphatic hydrocarbons, C6-C20 aromatic hydrocarbons, alcohol, ether or its mixture. In certain embodiments, the hydroformylation reaction solvent is selected from toluene, hexanaphthene, methyl tert-butyl ether, dimethylbenzene or its mixture. In an embodiment, the hydroformylation reaction solvent is dry, degassed toluene.

[0058] Typical hydroformylation reaction conditions that favor the formation of linear HBA over branched HMPA reaction products compared to typical commercial ethylene hydroformylation processes are at lower temperatures and moderate pressures. In certain embodiments, the hydroformylation reaction conditions include temperatures in the range of 20° C. to 120° C., 45° C. to 85° C., 50° C. to 80° C., 35° C. to 120° C., 45° C. to 95° C., or 50° C. to 70° C., or greater than or equal to 55° C., 60° C., or 65° C. In certain embodiments, the hydroformylation reaction conditions include moderate pressures, such as 137.9 kPa to 4136.85 kPa, 206.84 kPa to 2757.90 kPa, 275.79 kPa to 2068.42 kPa, 689.48 kPa to 2757.9 kPa, or 827.37 kPa to 2068.43 kPa.

[0059] The molar ratio of ethylene to carbon monoxide and hydrogen can vary as long as the linear:branched ratio can be maintained at or above 10. In an embodiment, the molar ratio of ethylene:carbon monoxide:hydrogen is in the range of (0.18-0.35):(2.7-4.1):(5-7).

[0060] The molar ratio of carbon monoxide to hydrogen (CO:H2) can be about 1:1, although this ratio can vary significantly. In embodiments, the syngas comprises a molar ratio of carbon monoxide to hydrogen in the range of 0.5:1.5 to 1.5:0.5, 0.8:1.2 to 0.9:1.1, or 0.95:1.05 to 0.98:1.12, or greater than or equal to 1:1.

[0061] If the reaction favors the formation of linear products over branched isomers and efficient water extraction is achieved, the molar ratio of ethylene to allyl alcohol can be in the range of 1:10 to 1:2. In embodiments, the molar ratio of ethylene to allyl alcohol is in the range of 1:10 to 1:3. In embodiments, the molar ratio of ethylene to allyl alcohol is in the range of 1:3 to 1:7, or 1:3.38 to 1:6.56, or 1:4 to 1:5. In some embodiments, the molar ratio of ethylene to allyl alcohol is about 1:4.37.

[0062] The partial pressure of CO can be in the range of 34.47 kPa to 689.48 kPa. The partial pressure of hydrogen can be in the range of 275.79 kPa to 1378.95 kPa. In an embodiment, the hydroformylation reaction is carried out under these conditions until most of the allyl alcohol has reacted, for example 60 to 99.9 mol%, and the product mainly includes 4-hydroxybutyraldehyde and some branched reaction products.

[0063] In certain embodiments, the starting concentration of allyl alcohol, based on the combined hydroformylation reaction solvent (catalyst solution) and AA feed, is calculated by the following formula: In an embodiment, the concentration of AA in the solution mixture is in the range of 5 wt % to 40 wt %.In an embodiment, a starting allyl alcohol concentration for the hydroformylation reaction in the range of 10 wt % to 25 wt % can be used.

[0064] The hydroformylation of allyl alcohol is carried out so that the CO concentration in the liquid phase during the hydroformylation ([CO] liq ) is maintained above 4 mmol / L (0.004M). [CO] liq The values ​​of are defined in U.S. Patent No. 6,225,509, the teachings of which are incorporated herein by reference for purposes not inconsistent with the present disclosure. In certain embodiments, the liquid phase hydrogen:carbon monoxide molar ratio is in the range of 10:1 to 1:2, or 5:1 to 1:2.

[0065] Extraction of the catalyst is essential in reducing production costs because it allows the catalyst to be recycled back into the reaction after product removal. By co-feeding gaseous ethylene and liquid allyl alcohol, the catalyst in the solvent can be easily separated from the hydroformylation product by water extraction, thereby reducing production costs.

[0066] The water-to-feed ratio refers to the weight ratio of water to the hydroformylation effluent, consisting of the catalyst solution and the aldehyde product, introduced into the extraction column. The water-to-feed ratio can affect the efficiency of the water extraction. In embodiments, the water-to-feed ratio ranges from 1:5 to 2:1, or from 1:3 to 1:1, or from 1:2 to 1:1.

[0067] The hydroformylation process of the present disclosure is conducted at temperatures lower than those used in conventional ethylene hydroformylation processes conducted at 90-120° C. The hydroformylation process of the present disclosure may be conducted at 50-100° C., or in other embodiments, at 50-80° C.

[0068] In one embodiment, a hydroformylation catalyst used in a hydroformylation process comprises Rh and a ligand of trans-1,2-bis(3,5-dimethylphenylphosphinomethyl)cyclobutane (hereinafter referred to as "ligand A"). In one embodiment, the molar ratio of Rh to ligand A is in a range of 1:1 to 1:5. In certain embodiments, the molar ratio of Rh to ligand A may be about 1:2.

[0069] Propionaldehyde is less polar than HBA and its branched isomer HMPA and therefore has a higher affinity for the toluene phase, thereby reducing the water extraction efficiency.

[0070] Co-feeding liquid allyl alcohol with gaseous ethylene to carry out the same hydroformylation reaction has not been accomplished due to challenges and difficulties in controlling the process to reduce or eliminate the production of unwanted by-products.

[0071] The following examples illustrate the range of ethylene co-feed amounts, the effect of the amount of CO or H2 on hydroformylation, the effect of water to feed ratio on extraction efficiency, and the effect of propionaldehyde on the linear:branched (L:B) ratio (HBA:HMPA) of the AA hydroformylation product.

[0072] Example 1: Batch Hydroformylation

[0073] Gaseous ethylene and liquid allyl alcohol were co-fed into the hydroformylation reactor using synthesis gas (50:50 hydrogen and carbon monoxide gas mixture). A (1:1:1) gas mixture of ethylene, hydrogen, and carbon monoxide obtained from Praxair was used as the gaseous feed. This feed allowed the simultaneous introduction of ethylene substrate and reagent synthesis gas. Rh-ligand A was used as catalyst. The first hydroformylation experiment used only the gaseous feed (1:1:1) to establish a baseline containing only ethylene. The second experiment involved the injection of allyl alcohol as a co-feed to demonstrate the generation of HBA, HMPA, and PA.

[0074] The hydroformylation reaction was carried out at 65°C using 1378.95 kPa of synthesis gas or in combination with ethylene as the gaseous feed. The catalyst comprised 200 ppm of rhodium and ligand A in toluene solvent with a molar composition of [Rh]:[ligand A]=1:2, and [Rh]=4.3×10 -5 Moore. Figure 3A and Figure 3B Syngas consumption is shown.

[0075] like Figure 3A and Figure 3B As can be seen in Figure 5, at 65°C, the hydroformylation of AA and ethylene independently of the catalyst system produces similar kinetics. This suggests that if run in the same reactor as a co-feed, both allyl alcohol and ethylene should be consumed in a similar manner.

[0076] Figure 4 The synthesis gas and ethylene consumption for allyl alcohol co-fed with ethylene are shown in Table 1. The hydroformylation results are summarized in Table 1.

[0077]

[0078]

[0079] As seen in Table 1, all of the ethylene was converted solely to propionaldehyde, as expected. Greater than 88 wt% of the allyl alcohol was converted to either linear HBA or branched HMPA, with a linear:branched ratio of 10 to 1, indicating that the majority of the product was linear HBA, which is more desirable than branched HMPA. The high yield of PA also indicates that the gaseous ethylene co-feed was well mixed to allow for simultaneous co-hydroformylation with AA.

[0080] Co-feeding gaseous ethylene with liquid allyl alcohol in the presence of the hydroformylation catalyst Rh-trans-1,2-bis(3,5-dimethylphenylphosphino-methyl)cyclobutane in the solvent produced a 10:1 molar ratio of linear to branched AA hydroformylation products, HBA and HMPA, and ethylene hydroformylation product, PA. Importantly, no increase in potential impurities, such as (2-methyl-1,3-pentanediol), which could be due to the high PA content, was observed. This demonstrates the apparent compatibility of the two feeds.

[0081] The use of the catalyst Rh-trans-1,2-bis(3,5-dimethylphenylphosphinomethyl)cyclobutane allows for co-hydroformylation at low temperatures (e.g., in the range of about 63° C. to 68° C.), unlike commercial ethylene hydroformylation using Rh-phosphite ligands at temperatures exceeding 100° C. and as high as 120° C. This makes the commercial process energy intensive, especially when combined with distillation of the propionaldehyde product from the hydroformylation catalyst solution.

[0082] Continuous hydroformylation

[0083] Allyl alcohol feed is introduced at a feed rate of 68.3 g / h, which corresponds to 11% of the catalyst and substrate feed rate of the hydroformylation process. Ethylene gas is fed separately and mixed with the independently fed synthesis gas components CO and H2, while nitrogen is added for balance to maintain a total flow of 300 SLH (standard liters per hour). The gases are then combined and injected into the reactor through a single ejector. Whenever ethylene is added to the feed system or when CO or H2 feed is adjusted under constant ethylene, the equivalent flow of nitrogen is reduced or increased to maintain a total of 300 SLH.

[0084] By varying the amount of ethylene feed, an effective reaction ratio of up to about 10 wt% of the combined ethylene and allyl alcohol weight feed rate (or an 18.6 molar feed ratio) is achieved. The ethylene concentration is calculated as follows: (weight of ethylene / (weight of AA + weight of ethylene)). Here, 10 wt% ethylene feed is equivalent to an 18.6% molar feed ratio because (7.52 g / (7.52 + 68.3 g) x 100% corresponds to 18.6% ((moles ethylene / moles of AA + moles of ethylene) x 100%).

[0085] The upper limit for ethylene is based on a loss in extraction efficiency. This is because when the ethylene feed exceeds 10 wt%, water extraction efficiency decreases due to the increased propionaldehyde concentration, increasing the miscibility of the toluene hydroformylation effluent with water, resulting in an inability to fully extract all of the produced propionaldehyde from the hydroformylation effluent of the catalyst solution and the produced aldehyde. Inadequate water extraction can cause some propionaldehyde to remain in the reactor and recycle back to the reactor along with the toluene catalyst solution, further reducing hydroformylation efficiency. Therefore, process control and the water extraction step contribute to the overall success of the production process.

[0086] Comparative Example 1-2: AA Feed

[0087] An average AA feed rate of 80 cc / hr (68.3 g / hr), corresponding to a feed concentration of 11 wt %, was introduced into the reactor at 930.79 kPa and 65° C.-68° C. The rhodium concentration was 150 ppm-210 ppm, with a ligand A:Rh molar ratio of 1.5-1.8, the amount of 1,4-bis(diphenylphosphino)butane (DPPB) was 100 ppm, and the amount of triphenylphosphine (TPP) was approximately 0.1%.

[0088] In order to fully dissolve the gas in the liquid to ensure selective reaction to the desired product, the H2 feed rate was maintained between 111 SLH and 131 SLH (equivalent to 13 to 16.5 mg-mol / L[H2] liq ), and the CO feed rate was maintained between 53 SLH and 68 SLH (equivalent to 10 to 15 mg-mol / L[CO] liq ). The gas mixture of CO and H2 was maintained at 300 SLH, with N2 as the balance. The same considerations apply to all the consecutive examples herein.

[0089] The product is carried in a toluene catalyst solution, which is then fed into an extraction column. Cold water is added from the top of the column, and the aldehyde product is extracted from the toluene catalyst solution in a countercurrent process. The toluene catalyst solution rises to the top of the column and overflows into a catalyst reservoir, from which it is reintroduced into the hydroformylation reactor.

[0090] The aldehyde product aqueous solution leaves the bottom of the extraction column and is further fed to a hydrogenation reactor. The hydrogenation catalyst is molybdenum-promoted sponge nickel, and during the hydrogenation reaction, linear 4-hydroxybutyraldehyde and branched 3-hydroxy-2-methylpropanal are converted to 1,4-butanediol and 2-methyl-1,3-propanediol, respectively, while the byproduct propionaldehyde is converted to n-propanol.

[0091] Table 2 shows the results for an allyl alcohol feed with only variable CO at a constant hydrogen feed of 63°C. As shown, similar reaction results were obtained at CO feed rates of 68 SLH and 63 SLH. Allyl alcohol conversion in the hydroformylation was >99.9%, with high selectivity to HBA and HMPA, >98.5%, and low C3 product selectivity, <1%. The low C3 selectivity indicates that the direct conversion from allyl alcohol to propionaldehyde was low (0.015 wt%), while after hydrogenation, overall, more than about 99 wt% of the allyl alcohol had been converted to linear (BDO) or branched aldehydes.

[0092] The results also show low losses of aqueous rhodium at <50 ppb. This amount of loss corresponds to rhodium dissolved in toluene, which is entrained in the aqueous phase leaving the extractor and therefore cannot be recycled back to the hydroformylation reactor.

[0093]

[0094]

[0095]

[0096] Example 2-5: Hydrogen Feed

[0097] Hydrogen feed was supplied between 111 SLH and 160 SLH at 65°C, and other reaction conditions were the same as those of Comparative Example 1. All examples had high AA conversion (99.9%), C3 selectivity (0.58 wt%-0.67 wt%), BDO selectivity (89.02 wt%-90.57 wt%), Comparable performance was demonstrated in terms of selectivity (8.78% to 8.93% by weight) and n-propanol / propionaldehyde yields (0.09% by weight / 0.02% by weight). While theoretically, the average n-propanol concentration in the hydroformylation of allyl alcohol is 0.1% by weight (0.32% selectivity), the results of Examples 2-5 doubled this to approximately 0.2% by weight (1.8 mmol / hr, approximately 0.64% selectivity). However, this still indicates that very little (approximately 0.2% by weight) of propionaldehyde is produced directly from the conversion of allyl alcohol in the hydroformylation. This 0.2% by weight is negligible in practical terms.

[0098] In addition, the lower catalyst losses during the water extraction process reduced the overall cost. Here, the rhodium catalyst losses were all below 60 ppb, comparable to Comparative Examples 1-2, indicating that a wide operating window of H2 feed rate (concentration) maintained stable performance and had no negative impact on the system.

[0099]

[0100]

[0101]

[0102] Examples 6-13: Ethylene Co-feed for Continuous Reactions

[0103] Examples 6-9 show ethylene feed at different flow rates, which increase n-propanol production while maintaining a linear:branched product ratio of 10 for the AA to BDO main process. The ethylene feed rate was varied between 4 SLH and 8 SLH, and CO was maintained at 68 SLH to ensure adequate supply, except for Example 6, where CO was maintained at 63 SLH compared to Example 4. Examples 10-13 varied the CO feed rate from 53 SLH to 85 SLH while maintaining the ethylene feed rate at 6 SLH. Other conditions were the same as in Comparative Example 1. The results are shown in Table 3.

[0104]

[0105]

[0106] The results in Table 3 were obtained by co-feeding up to 23.3 mol% ethylene with 68.3 g / hr of allyl alcohol (76.7 mol% of the total feed). Quantitative AA conversions >99.9% were observed under all conditions tested while maintaining the conversion of BDO and This again demonstrates that the co-feed of liquid allyl alcohol with gaseous ethylene successfully produces And n-propanol. Specifically, In contrast, Examples 6-12 showed ratios greater than 9.9-10, indicating that branched product pathways were not significantly increased. The requirement for success is to maintain The linear:linear ratio of the AA to BDO process was maintained above 10, especially in a system with four reactants and four possible products in two phases. The results show that by maintaining the ethylene co-feed at 7.52 g / hr = <9.92 wt%, the linear:linear ratio of the AA to BDO process was maintained above 10, which has not been demonstrated previously.

[0107] Example 13 provides a lower limit for the CO feed rate, which results in a significant decrease in the linear:branched ratio of 9.71. Here, when the CO feed rate is lower than that in Example 13, especially when ethylene is co-fed with AA, the selectivity of the linear product (BDO) decreases with the branched product. When allyl alcohol is the only feed, the split chain pathway is also the pathway to produce propionaldehyde and thus n-propanol.

[0108] With particular regard to C3 selectivity, the results show an increase in C3 yield (10.30 wt% in Example 6 versus 0.66 wt% in Comparative Example 1) while maintaining a linear:branched product ratio of 10 for the primary AA to BDO process. Examples 6 to 8 show that substantially the same amount of n-propanol as in Comparative Examples 1 or 2 is produced directly in the hydroformylation, approximately 0.08 wt%, indicating that direct hydrogenation of AA to propanol in the hydroformylation stage is not enhanced when ethylene is co-fed. One skilled in the art will recognize that this result implies that the pathway from AA to branched HMPA product (which also produces both PA and n-propanol) is not favored or enhanced when ethylene is co-fed with AA. This result is consistent with the observed The ratio remains at 10.

[0109] Comparison of the C3 selectivity calculated based on ethylene feed alone with the observed combined selectivity (baseline of ethylene feed alone + AA feed alone) shows good agreement with the quantitative process. Thus, in Example 6, the n-Pr selectivity for ethylene alone was 9.24 wt% based on GC analysis, while the baseline for Example 2 was 0.64 wt%, resulting in a total selectivity of 9.88 wt%, approximately 96% of the observed 10.3 wt%. This is within the expected error range for GC analysis. Similarly (Examples 8 / 10 / 11 / 12 all had calculated n-Pr selectivities of 13.25 wt% for an ethylene only feed, and observed combined n-Pr totals of 14.00 / 13.77 / 13.77 / 14.20 wt% selectivities. Again, all observations were within ±2% of the calculated ethylene only (13.25 wt%) + baseline n-Pr ~ (0.65 wt%), giving a total of 13.9 wt% combined n-Pr. This confirms the successful co-feeding of ethylene with AA to produce n-Pr and And for about 10 BDO and Example 9 shows the upper limit of the ethylene co-feed again being effectively extracted, still showing quantitative recovery of product, calculated ethylene only n-Pr, 16.92 wt% + 0.65 wt% baseline, giving a 17.57 wt% selectivity for combined n-Pr, compared to 17.3 wt% based on GC, again within experimental error.

[0110] Examples 9, 14 and 15: Extraction Efficiency

[0111] To determine the effect of water to feed ratio on extraction efficiency, the conditions according to Example 9 were repeated except that the water to feed ratio was gradually increased from 0.5 to 1.0. The results are shown in Table 4.

[0112]

[0113]

[0114]

[0115] As shown in Table 4, the lowest water-to-feed ratio in Example 9 also resulted in the least effective extraction and the highest Rh loss (88 ppb), indicating that some toluene was carried over into the aqueous phase exiting the extraction column. This was also confirmed by the lowest interfacial tension (4.09 dynes / cm). Furthermore, the highest retention of propionaldehyde in the aqueous extraction following the catalyst solution also made reintroduction of the catalyst into the reactor the least desirable.

[0116] Thus, when the water-to-feed ratio is increased to 0.7 (Example 14) and 1.0 (Example 15), the extraction efficiency is improved and the rhodium loss is reduced. However, these higher water-to-feed ratios (Examples 14 and 15) are undesirable in commercial applications because energy would be required to remove the excess water in the purification of the hydrogenated product. Therefore, a process with a water-to-feed ratio of ≤ 0.5 is more ideal.

[0117] In terms of C3 yield, all three examples showed expected actual C3 selectivities within the calculated range (Example 9 / 14 / 15 = 17.40 / 17.97 / 17.30) compared to the calculated ethylene only 16.92 wt% + baseline 0.65 wt% / (17.57 wt% selectivity). This again shows good agreement between theoretical (calculated) and observed selectivities based on GC analysis.

[0118] Taken together, Examples 8-12, co-feeding 18.6 mol% ethylene with allyl alcohol at a water-to-feed extraction ratio of 0.5, show an operating range with low rhodium catalyst losses (<50 ppb), matching the performance of the primary allyl alcohol-only feed process. Examples 6 and 7 demonstrate that additional ethylene can be added because an extraction ratio of 0.5 is superior to an extraction ratio of 1.0 in terms of rhodium losses (see 23 vs. 41 ppb). Without being bound by theory, Example 7 may have higher rhodium losses due to a higher water ratio with more rhodium in the reactor. However, the losses are still below 50 ppb.

[0119] In addition, maintaining the CO feed rate at 58 SLH (12.24 mg-mol / L or above) ensures that when ethylene is co-fed, the primary AA The process maintains a linear:branched ratio of at least 10. As previously mentioned, in Example 13, when the CO concentration in the system is too low to maintain the primary AA to The process selectivity was shown to decrease with a L:B ratio of 9.7 when the 53SLH and CO feed rates were adjusted.

[0120] Shows that for primary AA to The present disclosure demonstrates the benefits of combining allyl alcohol and ethylene hydroformylation without requiring new reactors or extraction equipment, while achieving quantitative n-propanol production and a primary process. product. Furthermore, the reaction can be carried out at lower temperatures to reduce energy costs while maintaining high conversion. The added benefit of n-propanol production has a wide range of applications.

[0121] While certain embodiments have been shown and described, modifications thereof can be made by one skilled in the art without departing from the teachings of this disclosure.

[0122] Once the above disclosure is fully understood, many other modifications, equivalents, and alternatives will become apparent to those skilled in the art. Where applicable, the appended claims are intended to be interpreted as encompassing such modifications, equivalents, and alternatives. Accordingly, the scope of protection is not limited by the above description, but only by the appended claims, which include equivalents of the subject matter of the claims.

Claims

1. A method for producing alcohols in a hydroformylation process comprising the following steps: a) introducing a gaseous mixture of ethylene, carbon monoxide and hydrogen into a reactor in a solvent in the presence of a hydroformylation catalyst; b) introducing liquid allyl alcohol into the reactor; and c) carrying out a hydroformylation reaction at a temperature between 50° C. and 100° C. to obtain a hydroformylation product; wherein after the hydroformylation reaction is completed, the reaction product is subjected to water extraction; and the aqueous aldehyde solution is subsequently subjected to hydrogenation.

2. The process according to claim 1, wherein the molar ratio of ethylene to allyl alcohol is in the range of 1:3 to 1:

7.

3. The process according to claim 1, wherein the molar ratio of ethylene to allyl alcohol is in the range of 1:4 to 1:

5.

4. The method according to claim 1, wherein the The concentration of allyl alcohol in the solvent was calculated to be in the range between 10 wt % and 25 wt %.

5. The method according to claim 1, wherein the molar ratio of ethylene:carbon monoxide:hydrogen is (0.18-0.35):(2.7-4.1):(5-7).

6. The method of claim 5, wherein the molar ratio of ethylene:carbon monoxide:hydrogen is 1:13:

22.

7. The process according to claim 1, wherein in step c), the hydroformylation reaction is carried out at a medium pressure ranging from 137.9 kPa to 1378.95 kPa.

8. The process according to claim 1, wherein in step c), the hydroformylation reaction is carried out at a moderate pressure ranging from 689.48 kPa to 1034.21 kPa.

9. The process according to claim 1, wherein in step c), the hydroformylation reaction is carried out at a medium pressure ranging from 896.32 kPa to 965.27 kPa.

10. The process of claim 1 , wherein the hydroformylation catalyst is a mixture of rhodium and a ligand selected from the group consisting of trans-1,2-bis(3,5-dimethylphenylphosphinomethyl)cyclobutane, ligand A, 1,4-bis(diphenylphosphinobutane) (DPPB), triphenylphosphine (TPP), bidentate diphosphates, and combinations thereof.

11. The method according to claim 10, wherein the molar ratio of rhodium to ligand A is in the range of 1:1 to 1:

5.

12. The method according to claim 10, wherein the molar ratio of rhodium to ligand A is 1:

2.

13. The process of claim 10, wherein the hydroformylation catalyst is a mixture of rhodium, Ligand A, DPPB, and TPP.

14. The method of claim 13, wherein the molar ratio of rhodium:ligand A:DPPB:TPP is 1:2:0.1:

2.

15. The method of claim 10, wherein the rhodium is present in an amount of 50 ppm to 500 ppm.

16. The method of claim 1, wherein in step c), the temperature is between 50°C and 80°C.

17. The method according to claim 1, further comprising the steps of: The product is separated from the solvent and the catalyst by water extraction.

18. The process according to claim 17, wherein the water-to-feed ratio in the water extraction procedure is in the range of 1:5 to 2:1, wherein the water-to-feed ratio refers to the weight ratio of water to the hydroformylation effluent consisting of the catalyst solution and the aldehyde product introduced into the extraction column.

19. Use of a catalyst system for the hydroformylation of allyl alcohol and ethylene, the catalyst system comprising rhodium and a ligand, wherein the ligand is selected from the group consisting of trans-1,2-bis(3,5-dimethylphenylphosphinomethyl)cyclobutane, i.e., Ligand A, 1,4-bis(diphenylphosphinobutane) (DPPB), triphenylphosphine (TPP), bidentate diphosphates, and combinations thereof.

20. Use according to claim 19, wherein the molar ratio of rhodium to ligand A is in the range of 1:1 to 1:5.

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