Method for preparing isononanoic acid ester through olefin hydrogen esterification

Abstract

The invention relates to the technical field of preparation of oxygen-containing compounds, and discloses a method for preparing isononanoic acid ester through olefin hydrogen esterification, and the method comprises the following steps: in the presence of CO, introducing an alcohol solvent, a fresh catalyst material and an olefin material into a hydrogen esterification reactor, and carrying out hydrogen esterification reaction to obtain a hydrogen esterification reaction crude product; and separating the crude product of the hydrogen esterification reaction to obtain an ester phase material and a circulating catalyst material which can be circulated to the hydrogen esterification reactor to participate in the hydrogen esterification reaction again. According to the method disclosed by the invention, in the separation process of the crude product, most of the catalyst does not need to stay for a long time in a carbon monoxide-free atmosphere and is continuously heated, so that the activity decline speed of the catalyst is slower when the catalyst is recycled, the stability of the activity of the catalyst is facilitated, and the service life of the catalyst is prolonged.

Description

Technical Field

[0001] This invention relates to the field of oxygen-containing compound preparation technology, and specifically to a method for preparing isononanoic acid ester by olefin hydrogen esterification. Background Technology

[0002] Isononanoic acid is a basic raw material for fine organic chemicals with a wide range of applications. It can be used to synthesize high-grade lubricating oils and coatings, as well as as a raw material for synthetic lubricants, pharmaceutical intermediates, metal soaps, and metalworking fluids. It is also suitable for modifying alkyd resins, improving their resistance to yellowing and impact resistance. It can be used in the cosmetics industry, and its metal salts can be used as paint drying agents, vinyl stabilizers, polyvinyl chloride stabilizers and preservatives, tire bonding aids, and for various other purposes.

[0003] Existing methods for synthesizing isononanoic acid involve the hydroformylation of olefins to aldehydes, followed by oxidation to an acid using a homogeneous metal salt catalyst. However, due to side reactions and limitations in reaction conditions, the purity and yield of most products are low. The resulting acid can then react with fatty alcohols to form isononanoic acid esters, a lengthy process, and the oxidation reaction carries a high risk of combustion and explosion due to the involvement of the oxidant.

[0004] CN116237086A discloses a catalyst system for the carbonylation of ethylene to produce methyl propionate based on an antioxidant strategy. The catalyst system includes a palladium salt, a phosphine ligand, a co-catalyst, and an antioxidant; the antioxidant is a phenolic compound, ascorbic acid, ascorbic acid ester, or an inorganic salt derivative; the palladium salt is a divalent palladium salt; the phosphine ligand includes monodentate, bidentate, and multidentate phosphine containing chain and cyclic alkyl and / or aryl groups; the co-catalyst is any one or more of sulfonic acid, trivalent aluminum salt, trivalent iron salt, divalent copper salt, or water.

[0005] WO1996019434A1 discloses a catalyst system capable of catalyzing the carbonylation of ethylene and a method of using such a system, wherein the catalyst system can be combined with a Group VIII metal, such as a Group VIII metal, to obtain palladium or a compound thereof and a bidentate phosphine, such as bis(di-tert-butylphosphino)-o-xylene.

[0006] WO2001068583A3 discloses a process for carbonylating an ethylenically unsaturated compound having 3 or more carbon atoms by reacting with carbon monoxide and a hydroxy compound in the presence of a catalyst system. The catalyst system comprises (a) a source of palladium cations; (b) a bidentate diphosphine of formula (I): R1R2>P-R3-R-R4-P<R5R6, where P represents a phosphorus atom; R1, R2, R5 and R6 independently represent the same or different optionally substituted organic groups containing a tertiary carbon atom, which is linked to the phosphorus atom through the tertiary carbon atom; R3 and R4 independently represent an optionally substituted alkylene group and R represents an optionally substituted aryl group; (c) a source of anions derived from an acid having a pKa less than 3.

[0007] WO2003070370A1 discloses a process for carbonylating an ethylenically unsaturated compound with carbon monoxide and a co-reactant. The carbonylation reaction is carried out in the presence of a novel catalyst comprising: a) a source of Group VIII metal, b) a bidentate diphosphine.

[0008] In the prior art, the focus has mainly been on the screening and preparation of catalyst ligands, and there has been little involvement in the separation method of the crude product, and there is a defect that the catalyst is prone to deactivation. SUMMARY OF THE INVENTION

[0009] The object of the present invention is to overcome the defects in the olefin hydroesterification technology provided by the prior art, such as long reaction process, unstable catalyst activity and rapid deactivation of the catalyst.

[0010] To achieve the above object, the present invention provides a process for preparing isononanoate by olefin hydroesterification, which process comprises:

[0011] (A) In the presence of CO, introducing an alcohol solvent, a fresh catalyst material and an olefin material into a hydroesterification reactor for hydroesterification reaction to obtain a crude hydroesterification product;

[0012] (B) Subjecting the liquid phase product obtained after gas-liquid separation of the crude hydroesterification product to alcohol solvent evaporation treatment and then to a layering treatment to obtain a first ester phase and a first recycled catalyst that can be recycled to the hydroesterification reactor to participate in the hydroesterification reaction again;

[0013] In step (A), the fresh catalyst material contains a palladium complex and a ligand; the mass ratio of the ligand to the palladium complex is 0.01 - 100:1; in the fresh catalyst material, the mass concentration of the palladium complex is 0.01% - 5%;

[0014] The olefin material is C 2～20 olefin.

[0015] The solution provided by the present invention has at least the following advantages:

[0016] 1. In the method of the present invention, diisobutylene can be directly synthesized into isononanoate through a hydromethyl esterification reaction, avoiding the high risk of oxidation reaction. Isononanoate can be used to prepare isononanoic acid. Therefore, the method of the present invention can significantly simplify the reaction process.

[0017] 2. In the method of the present invention, during the separation of crude products, most of the catalysts do not need to remain in a carbon monoxide-free atmosphere for a long time and be continuously heated, which makes the catalyst activity decrease more slowly during recycling, which is more conducive to the stability of catalyst activity and extends the service life of the catalyst.

[0018] 3. The method of the present invention is applicable to a wide range of olefin feedstocks, especially suitable for the hydrogen esterification reaction of multi-branched olefins with large steric hindrance, and has the advantages of low reaction pressure, low equipment investment and significantly reduced processing costs.

[0019] 4. The method of the present invention has high olefin conversion rate and isonononate selectivity;

[0020] 5. The catalyst involved in the method of the present invention can be recycled. During the recycling process, a small amount of ligand and a small amount of promoter are added; or only a small amount of ligand is added; or only a small amount of promoter is added; or even no ligand and promoter are added, which can prevent the catalyst activity from decreasing or slow down the rate of decrease in catalyst activity, or even increase the activity of the deactivated catalyst. Detailed Implementation

[0021] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0022] As previously stated, this invention provides a method for preparing isononanoic acid esters by olefin hydrogen esterification, the method comprising:

[0023] (A) In the presence of CO, alcohol solvent, fresh catalyst material and olefin material are introduced into hydrogen esterification reactor to carry out hydrogen esterification reaction to obtain crude product of hydrogen esterification reaction;

[0024] (B) The liquid phase product obtained after gas-liquid separation of the crude product of the hydrogen esterification reaction is subjected to alcohol solvent treatment and layering treatment in sequence to obtain the first ester phase and the first circulating catalyst that can be recycled to the hydrogen esterification reactor to participate in the hydrogen esterification reaction again.

[0025] In step (A), the fresh catalyst material contains a palladium complex and a ligand; the mass ratio of the ligand to the palladium complex is 0.01-100:1; and the mass concentration of the palladium complex in the fresh catalyst material is 0.01%-5%.

[0026] The olefin material is C 2～20 Olefins.

[0027] Preferably, the alcohol solvent evaporation treatment and the layering treatment are carried out under normal pressure.

[0028] Preferably, the palladium complex of the present invention is selected from at least one of palladium dichloride, bis(acetonitrile)palladium dichloride, palladium acetate, palladium trifluoroacetate, bis(triphenylphosphine)palladium dichloride, (1,5-cyclooctadiene)palladium dichloride, allyl palladium chloride, tetratriphenylphosphine palladium, bis(acetylacetone)palladium, bis(dibenzylacetone)palladium, and tri(dibenzylacetone)palladium.

[0029] Preferably, in step (A), the hydrogen esterification reactor further contains an acid auxiliary agent that participates in the hydrogen esterification reaction.

[0030] More preferably, the acid additive is selected from at least one of organic sulfonic acids, boric acid, benzoic acid, salicylic acid, and Lewis acids containing trifluoromethanesulfonate; the organic sulfonic acids include p-toluenesulfonic acid, benzenesulfonic acid, naphthalenesulfonic acid, quinoline-8-sulfonic acid, dodecylbenzenesulfonic acid, trifluoromethanesulfonic acid, and methanesulfonic acid; the Lewis acids containing trifluoromethanesulfonate include aluminum trifluoromethanesulfonate, scandium trifluoromethanesulfonate, and bismuth trifluoromethanesulfonate.

[0031] In a preferred embodiment, in step (A), the mass ratio of the ligand to the palladium complex is 0.1-20:1; more preferably, it is 1-10:1.

[0032] Preferably, in step (A), the mass concentration of the palladium complex in the fresh catalyst material is 0.1%-3%, more preferably 0.5%-1.5%, and even more preferably 0.6%-1%.

[0033] According to a preferred embodiment, in step (A), the ligand in the fresh catalyst material is provided by at least one of the following substances:

[0034] 1,2-bis(diphenylphosphine)ethane, 1,3-bis(diphenylphosphine)propane, 1,4-bis(diphenylphosphine)butane, 1,1'-bis(diphenylphosphine)ferrocene, 1,1'-binaphthyl-2,2'-bisdiphenylphosphine, 4,5-bis(diphenylphosphine)-9,9-dimethyloxanthracene, 4,5-bis(diphenylphosphine oxide)-9,9-dimethyloxanthracene, 4,6-bis(diphenylphosphine)phenazine 1,2-bis(di-tert-butylphosphine)benzene, 1,1'-bis(di-tert-butylphosphine)ferrocene, tris(2,4-di-tert-butyl)phosphite, trimethylolpropane phosphite, 2,2′-bis[(1,1'-biphenyl-2,2'-diyl)phosphite]-3,3'-di-tert-butyl-5,5'-dimethoxy-1,1'-biphenyl and phosphorus-containing ligands containing P,O-hetero-groups;

[0035] The phosphorus-containing ligand containing the P,O-heteromeric group is selected from at least one of L1, L2, L3, L4, L5, and L6;

[0036]

[0037] Particularly preferably, the ligand is provided by at least one of L1, L2, L3, L4, L5, and L6.

[0038] Preferably, in step (A), the temperature of the hydrogen esterification reaction is 60℃-250℃, more preferably 90℃-200℃, even more preferably 100℃-160℃, and particularly preferably 100℃-140℃.

[0039] The hydrogen esterification reactor of the present invention preferably consists of two or more reactors connected in series. Preferably, the hydrogen esterification reactor consists of two reactors connected in series. The temperatures of the two reactors connected in series can be the same or different. The reaction temperatures can be equal, lower at the beginning and higher at the end, or higher at the beginning and lower at the end. The residence time of the material in the high-temperature reaction zone should be reduced, which helps to reduce the residence time of the catalyst in the higher reaction temperature zone and reduce catalyst decomposition.

[0040] The CO can flow in from the bottom of the hydrogen esterification reactor, or from the bottom of multiple hydrogen esterification reactors. Furthermore, the ratio of carbon monoxide to olefins flowing into different hydrogen esterification reactors can be the same or different. This allows for easy adjustment of the CO to olefin ratio in each hydrogen esterification reactor to achieve the optimal ratio, which is beneficial for higher conversion and better selectivity. Particularly preferred is a CO to olefin molar ratio of 1-12:1, more preferably 3-6:1.

[0041] Preferably, in step (A), the pressure of the hydrogen esterification reaction is 1 MPa-12 MPa, more preferably 2 MPa-10 MPa, and even more preferably 5 MPa-8 MPa.

[0042] In a preferred embodiment, in step (A), the hydrogen esterification reaction takes 1-40 hours, more preferably 3-20 hours, and even more preferably 5-10 hours.

[0043] According to a particularly preferred embodiment, the method further includes adding ligands and / or acid auxiliaries to the hydrogen esterification reaction system when the first recycled catalyst is involved in the hydrogen esterification reaction again.

[0044] Preferably, the weight ratio of the added ligand to the initially added ligand participating in the hydrogen esterification reaction is 0.07-200:100, more preferably 1-100:100, and even more preferably 16-36:100.

[0045] Preferably, the weight ratio of the added acid auxiliaries to the initially added acid auxiliaries for participating in the hydrogen esterification reaction is 0.02-200:100, more preferably 1-150:100, and even more preferably 4-100:100.

[0046] Preferably, in step (A), the weight ratio of the initially added olefin material to the initially added fresh catalyst material (based on ligands) is 100:0.01-50; more preferably, it is 100:0.1-10.

[0047] According to a particularly preferred embodiment, the method further includes:

[0048] The first ester phase is subjected to distillation and / or rectification to obtain a refined ester phase material, and optionally also to obtain a second recycled catalyst;

[0049] The first circulating catalyst, or the first circulating catalyst and the second circulating catalyst, are used as circulating catalyst materials.

[0050] Preferably, in step (B), the conditions of the alcohol solvent treatment are controlled such that the alcohol solvent content in the liquid product before the layering treatment is less than 0.1 wt%.

[0051] Particularly preferred, the alcohol solvent is C 1-6 Alcohol. Particularly preferably, the alcohol solvent is at least one selected from methanol, ethanol, and n-butanol.

[0052] Preferably, the hydrogen esterification reactor is a batch reactor and / or a tubular reactor.

[0053] In this invention, when the recycled catalyst material is recycled back to the inlet of the hydrogen esterification reactor, a small amount of ligand and / or acid additive may be added as needed.

[0054] The olefins in the olefin material described in this invention can be straight-chain olefins and / or branched-chain olefins, wherein the branched-chain olefins have ≥1 branch. Preferably, the olefin material is C 6～20 Olefins.

[0055] Preferably, the olefin material is a C8 olefin material.

[0056] Particularly preferably, the olefin material is 2,4,4-trimethyl-1-pentene and / or 2,4,4-trimethyl-2-pentene. Trimethyl multi-branched olefins are more difficult to hydrogenate than few-branched olefins due to their large steric hindrance. However, the inventors of this invention have discovered that the present invention can maintain high catalyst activity while achieving nearly 100% product selectivity in the hydrogenation reaction of trimethyl multi-branched olefins.

[0057] In a particularly preferred embodiment, the olefin material is 2,4,4-trimethyl-1-pentene and 2,4,4-trimethyl-2-pentene, and the content of 2,4,4-trimethyl-1-pentene in the olefin material is 70-80 wt%, and the content of 2,4,4-trimethyl-2-pentene is 15-30 wt%.

[0058] According to a particularly preferred embodiment of the present invention, the method includes:

[0059] (1) In the presence of CO, alcohol solvent, fresh catalyst material and olefin material are introduced into hydrogen esterification reactor to carry out hydrogen esterification reaction to obtain crude product of hydrogen esterification reaction.

[0060] (2) The liquid phase product obtained after gas-liquid separation of the crude product of the hydrogen esterification reaction is subjected to alcohol solvent treatment and layering treatment in sequence to obtain the first ester phase and the first circulating catalyst that can be recycled to the hydrogen esterification reactor to participate in the hydrogen esterification reaction again.

[0061] (3) The first ester phase is subjected to distillation and / or rectification to obtain refined ester phase material and second circulating catalyst.

[0062] The first circulating catalyst, or the first circulating catalyst and the second circulating catalyst, are used as circulating catalyst materials.

[0063] The hydrogen esterification reaction of the present invention can be carried out at lower temperatures and lower pressures.

[0064] After the hydrogen esterification reaction of the present invention is completed, the crude product of the hydrogen esterification reaction is separated into gas and liquid phases to separate carbon monoxide. After distilling off the remaining alcohol solvent and unreacted olefin raw materials, the product is cooled to room temperature and subjected to sedimentation and separation. The upper layer is the first ester phase, and the lower layer is the first circulating catalyst containing palladium complex, ligands, and auxiliaries. The first ester phase is separated, and the first circulating catalyst is returned to the hydrogen esterification reactor for recycling. The first ester phase is collected by distillation or rectification to obtain a high-purity ester. The remaining trace amount of palladium complex can also be returned to the hydrogen esterification reactor for recycling as a second circulating catalyst.

[0065] When the hydrogen esterification reactor is a tubular reactor, preferably, CO, alcohol solvent, fresh catalyst material, and olefin material flow into the tubular reactor from the bottom, and the reaction products flow out from the top of the tubular reactor.

[0066] When the hydrogen esterification reactor is a tubular reactor, preferably, CO, alcohol solvent, fresh catalyst material, and olefin material flow into the tubular reactor from the top, and the reaction products flow out from the bottom.

[0067] The present invention involves distilling and / or rectifying the first ester phase, which can be done under atmospheric or vacuum conditions. The distillation or rectification apparatus can be a vacuum or atmospheric pressure distillation kettle, a distillation column, or a thin-film evaporator, or other distillation and rectification apparatus known in the art. Exemplarily, the pressure of the vacuum distillation kettle or distillation column is ≤10. -2 MPa, preferably ≤10 MPa -3 MPa, more preferably ≤10 MPa -4 MPa; column bottom temperature 70-200℃; thin film evaporator pressure ≤10mmHg, preferably ≤6mmHg, more preferably ≤1mmHg, heating surface temperature 35-150℃, preferably 40-100℃, more preferably 45-70℃, residence time 1-30 minutes, preferably 1-10 minutes, more preferably 1-2 minutes. If a distillation column is used, the reflux ratio is 1-20:1, preferably 1-10:1.

[0068] The gas-liquid separation can be carried out in a gas-liquid separation tank under conditions of cooling without pressure reduction. For example, the gas-liquid separation temperature is 0℃-100℃, preferably 20℃-80℃, and more preferably 20℃-40℃. The gaseous stream obtained after gas-liquid separation is CO. After condensation and / or absorption, the CO can be recycled to the inlet of the hydrogen esterification reactor for reuse.

[0069] The liquid phase stream after gas-liquid separation can be distilled using a distillation apparatus. The top product is alcohol, and the bottom product is a catalyst containing esters and palladium complexes. The ester-containing catalyst solution is cooled and allowed to settle and separate into two phases. The ester phase is separated, and the catalyst phase is recycled to the hydrogen esterification reactor for reuse. The ester phase can be used directly as a product, or it can be distilled or purified to collect the distilled ester, yielding a high-purity ester. The remaining trace amounts of palladium complexes can be returned to the hydrogen esterification reactor for recycling.

[0070] The present invention will be described in detail below through examples. In the following examples, unless otherwise specified, the raw materials used are all commercially available products.

[0071] The olefin feedstock in the example is a commercially available C8 olefin with the following composition: 75.1 wt% 2,4,4-trimethyl-1-pentene, 21.2 wt% 2,4,4-trimethyl-2-pentene, and the balance being other multi-branched olefins.

[0072] The hydrogen esterification reactor used below is a single batch reactor.

[0073] For the synthesis of L3 ligands, see the similar method disclosed in Journal of Catalysis (2023), 426, 214-221.

[0074] The palladium complex used below is palladium acetate.

[0075] The acid additive used below is p-toluenesulfonic acid.

[0076] The following olefin conversion rates are calculated separately for each cycle. That is, for example, in the first cycle (which is the second hydrogen esterification reaction), the feedstock involved in the formula for calculating the olefin conversion rate refers to the feedstock for the second hydrogen esterification reaction, not all feedstock including both the first and second hydrogen esterification reactions. The same concept applies to the products. Specifically, the formula for calculating the olefin conversion rate is: Olefin conversion rate = (moles of olefins in the feedstock - moles of olefins in the hydrogen esterification reaction products) / moles of olefins in the feedstock × 100%.

[0077] The formula for calculating the selectivity of methyl isononanoate is: (number of moles of methyl isononanoate in the hydrogen esterification product / total number of moles of the hydrogen esterification product) × 100%.

[0078] Example 1

[0079] (1) 0.6 g of palladium complex, 5 g of L3 ligand, 5 g of acid auxiliary agent, 112 g of C8 olefin and 96 g of methanol were added to the hydrogen esterification reactor. The reaction was carried out for 5 h under CO pressure of 3 MPa and 120 °C to obtain crude product. The olefin conversion rate was 98 mol% and the selectivity of methyl isononanoate was nearly 100 mol%.

[0080] (2) The crude product of the reaction is separated by gas-liquid separation, and CO is separated and recycled. The crude liquid product is distilled off with methanol under normal pressure, cooled, and separated by sedimentation and stratification. The catalyst is recycled to the hydrogen esterification reactor.

[0081] (3) Second use of catalyst:

[0082] The recycled catalyst obtained in step (2) was recycled to the hydrogen esterification reactor, and 0.7 g of L3 ligand, 0.2 g of acid promoter, 112 g of C8 olefin and 96 g of methanol were added. The reaction was carried out under the same reaction conditions as in step (1) to obtain the crude product. According to the test and calculation, the olefin conversion rate was 98 mol% and the selectivity of methyl isononanoate was nearly 100 mol%.

[0083] (4) Continue separation in the manner described in step (2) of this embodiment, and use the catalyst for the third time:

[0084] The recycled catalyst obtained in step (3) was recycled to the hydrogen esterification reactor, and 112 g of C8 olefin and 96 g of methanol were added, along with 0.7 g of L3 ligand and 0.2 g of acid auxiliary agent. The reaction was carried out under the same reaction conditions as in step (3) to obtain the crude product. According to the test and calculation, the olefin conversion rate was 95 mol% and the selectivity of methyl isononanoate was nearly 100 mol%.

[0085] (5) Continue separation as described above, and use the catalyst for the fourth time:

[0086] The recycled catalyst obtained in step (4) was recycled to the hydrogen esterification reactor, and 112 g of C8 olefin and 96 g of methanol were added, along with 0.7 g of L3 ligand and 0.2 g of acid auxiliary agent. The reaction was carried out under the same reaction conditions as in step (3) to obtain the crude product. According to the test and calculation, the olefin conversion rate was 93 mol% and the selectivity of methyl isononanoate was nearly 100 mol%.

[0087] Comparative Example 1

[0088] The reaction was carried out according to the method of Example 1, except that the product separation was different. Specifically,

[0089] In step (2), after methanol is distilled off from the crude liquid product at atmospheric pressure, it is then subjected to a process at 20 × 10⁻⁶ ppm. -3Under the same conditions, methyl isononanoate was distilled off, and the remaining catalyst was recycled to the hydrogen esterification reactor for reuse. Everything else was the same as in Example 1. Catalyst recycling was carried out in this process (and the same product separation steps as in this comparative example were used each time).

[0090] In the third use of the catalyst corresponding to step (4) of Example 1, the results were: olefin conversion of 83 mol% and methyl isononanoate selectivity of nearly 100 mol%.

[0091] In the fourth use of the catalyst corresponding to step (5) of Example 1, the results were: olefin conversion of 66 mol% and methyl isononanoate selectivity of nearly 100 mol%.

[0092] A comparison of the results of Example 1 and Comparative Example 1 shows that the scheme according to the present invention is more likely to maintain the high activity of the catalyst.

[0093] Example 2

[0094] The difference in catalyst recycling according to the method of Example 1 is:

[0095] When the catalyst corresponding to step (3) of Example 1 was recycled, no L3 ligand was added, only 5g of acid promoter was added. Everything else was the same as in Example 1. The results were: olefin conversion of 96mol% and methyl isononanoate selectivity of nearly 100mol%.

[0096] The recycled catalyst obtained in the previous step was recycled to the hydrogen esterification reactor. No L3 ligand was added, only 0.2 g of acid promoter was added. Everything else was the same as in Example 1. The results were: olefin conversion of 96 mol% and methyl isononanoate selectivity of nearly 100 mol%.

[0097] Example 3

[0098] Except for the addition of 1.1g of acid auxiliary agent in each reaction, the catalyst was recycled according to step (3) in Example 1. When the catalyst was repeated for the 15th reaction, 1.3g of L3 ligand and 0.2g of acid auxiliary agent were added. All other steps were the same as step (3) in Example 1. The results showed that the olefin conversion rate increased from 66mol% when the catalyst was repeated for the 14th reaction to 76mol%, and the selectivity of methyl isononanoate was close to 100mol%.

[0099] Example 4

[0100] The catalyst was recycled according to step (3) of the method in Example 1. When the catalyst was repeated for the 16th reaction, 1.4 g of L3 ligand and 0.2 g of acid promoter were added. Everything else was the same as step (3) of Example 1. The result was that the olefin conversion rate was 82 mol% and the methyl isononanoate selectivity was nearly 100 mol% when the catalyst was repeated for the 16th reaction. When the catalyst was repeated for the 17th, 18th, 19th and 20th reactions according to step (3) of the method in Example 1, everything else was the same as step (3) of Example 1, except that the L3 ligand and acid promoter were not added each time. The result was that the olefin conversion rates were 85 mol%, 88 mol%, 88 mol%, and 88 mol% respectively when the catalyst was repeated for the 17th, 18th, 19th and 20th reactions, and the methyl isononanoate selectivity was nearly 100 mol% in all cases.

[0101] As can be seen from the comparison results between Example 1 and Comparative Example 1, the method provided by the present invention has a shorter reaction process, makes it easier to maintain high catalyst activity, is beneficial to catalyst activity stability, and extends catalyst life.

[0102] Furthermore, the results of the above embodiments also show that adding a small amount of ligand and acid promoter, or adding either ligand or acid promoter, can slow down catalyst deactivation or improve catalyst activity. When neither ligand nor acid promoter is added at the appropriate time, the olefin conversion rate does not decrease or increases slightly, and the selectivity of methyl isononanoate is close to 100 mol%.

[0103] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing isononanoic acid ester by hydrogen esterification of an olefin, characterized in that, The method includes: (A) In the presence of CO, alcohol solvent, fresh catalyst material and olefin material are introduced into hydrogen esterification reactor to carry out hydrogen esterification reaction to obtain crude product of hydrogen esterification reaction; (B) The liquid phase product obtained after gas-liquid separation of the crude product of the hydrogen esterification reaction is subjected to alcohol solvent treatment and layering treatment in sequence to obtain the first ester phase and the first circulating catalyst that can be recycled to the hydrogen esterification reactor to participate in the hydrogen esterification reaction again. In step (A), the fresh catalyst material contains a palladium complex and a ligand; the mass ratio of the ligand to the palladium complex is 0.01-100:1; and the mass concentration of the palladium complex in the fresh catalyst material is 0.01%-5%. The olefin material is C 2～20 Olefins.

2. The method for preparing isonononate by olefin hydrogen esterification according to claim 1, characterized in that, In step (A), the mass ratio of the ligand to the palladium complex is 0.1-20:1; preferably 1-10:

1.

3. The method for preparing isononanoic acid ester by olefin hydrogen esterification according to claim 1 or 2, characterized in that, In step (A), the mass concentration of the palladium complex in the fresh catalyst material is 0.1%-3%, preferably 0.5%-1.5%, and more preferably 0.6%-1%. Preferably, the fresh catalyst material further contains an acid promoter, and the acid promoter is preferably selected from at least one of organic sulfonic acids, boric acid, benzoic acid, salicylic acid, and Lewis acids containing trifluoromethanesulfonate; the organic sulfonic acids include p-toluenesulfonic acid, benzenesulfonic acid, naphthalenesulfonic acid, quinoline-8-sulfonic acid, dodecylbenzenesulfonic acid, trifluoromethanesulfonic acid, and methanesulfonic acid; the Lewis acids containing trifluoromethanesulfonate include aluminum trifluoromethanesulfonate, scandium trifluoromethanesulfonate, and bismuth trifluoromethanesulfonate.

4. The method for preparing isononanoic acid ester by olefin hydrogen esterification according to any one of claims 1-3, characterized in that, In step (A), the hybrid ligand in the fresh catalyst material is provided by at least one of the following substances: 1,2-bis(diphenylphosphine)ethane, 1,3-bis(diphenylphosphine)propane, 1,4-bis(diphenylphosphine)butane, 1,1'-bis(diphenylphosphine)ferrocene, 1,1'-binaphthyl-2,2'-bisdiphenylphosphine, 4,5-bis(diphenylphosphine)-9,9-dimethyloxanthracene, 4,5-bis(diphenylphosphine oxide)-9,9-dimethyloxanthracene, 4,6-bis(diphenylphosphine)phenazine 1,2-bis(di-tert-butylphosphine)benzene, 1,1'-bis(di-tert-butylphosphine)ferrocene, tris(2,4-di-tert-butyl)phosphite, trimethylolpropane phosphite, 2,2'-bis[(1,1'-biphenyl-2,2'-diyl)phosphite]-3,3'-di-tert-butyl-5,5'-dimethoxy-1,1'-biphenyl and phosphorus-containing ligands containing P,O-hetero-groups; The phosphorus-containing ligand containing the P,O-heteromeric group is selected from at least one of L1, L2, L3, L4, L5, and L6; Preferably, the ligand is provided by at least one substance selected from L1, L2, L3, L4, L5, and L6.

5. The method for preparing isononanoic acid ester by olefin hydrogenation according to any one of claims 1-4, characterized in that, In step (A), the molar ratio of CO to olefin is 1-12:1, more preferably 3-6:

1.

6. The method for preparing isononanoic acid ester by olefin hydrogen esterification according to any one of claims 1-4, characterized in that, The method further includes: when the first recycled catalyst participates in the hydrogen esterification reaction again, adding ligands and / or acid auxiliaries to the hydrogen esterification reaction system; Preferably, the weight ratio of the added ligand to the initially added ligand participating in the hydrogen esterification reaction is 0.07-200:100, more preferably 1-100:100, and even more preferably 16-36:100; Preferably, the weight ratio of the added acid auxiliaries to the initially added acid auxiliaries for participating in the hydrogen esterification reaction is 0.02-200:100, more preferably 1-150:100, and even more preferably 4-100:

100.

7. The method for preparing isononanoic acid ester by olefin hydrogen esterification according to any one of claims 1-4, characterized in that, In step (A), the temperature of the hydrogen esterification reaction is 60°C-250°C, preferably 90°C-200°C, and more preferably 100°C-160°C; Preferably, in step (A), the pressure of the hydrogen esterification reaction is 1 MPa-12 MPa, more preferably 2 MPa-10 MPa, and even more preferably 5 MPa-8 MPa; Preferably, in step (A), the hydrogen esterification reaction takes 1-40 hours, more preferably 3-20 hours, and even more preferably 5-10 hours.

8. The method for preparing isononanoic acid ester by olefin hydrogen esterification according to any one of claims 1-7, characterized in that, The method also includes: The first ester phase is subjected to distillation and / or rectification to obtain a refined ester phase material, and optionally also to obtain a second recycled catalyst; The first circulating catalyst, or the first circulating catalyst and the second circulating catalyst, are used as circulating catalyst materials.

9. The method for preparing isononanoic acid ester by olefin hydrogenation according to any one of claims 1-8, characterized in that, In step (B), the conditions of the alcohol solvent treatment are controlled such that the alcohol solvent content in the liquid product before the layering treatment is less than 0.1 wt%.

10. The method for preparing isononanoic acid ester by hydrogen esterification of olefins according to any one of claims 1-8, characterized in that, The hydrogen esterification reactor is a batch reactor and / or a tubular reactor.

11. The method for preparing isononanoic acid ester by olefin hydrogenation according to any one of claims 1-10, characterized in that, The olefin material is a C8 olefin material; Preferably, the olefin material is 2,4,4-trimethyl-1-pentene and / or 2,4,4-trimethyl-2-pentene.

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