Preparation method and application of terephthalic acid hydrogenation catalyst

Abstract

The invention relates to a preparation method and application of a terephthalic acid hydrogenation catalyst. The preparation method of the terephthalic acid hydrogenation catalyst comprises the following steps: S1, carrying out heat treatment on a mixture containing a palladium source and a carrier in a first mixed gas atmosphere to obtain a heat treatment product, and S2, carrying out reduction treatment on the heat treatment product in the step S1 in a second mixed gas atmosphere to obtain the terephthalic acid hydrogenation catalyst, wherein the first mixed gas is prepared from inert gas and C3-C10 monocarboxylic acid. When the catalyst prepared by the preparation method provided by the invention is applied to hydrofining of crude terephthalic acid, the conversion rate of 4-CBA can be effectively improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of catalysts, and particularly relates to a preparation method and application of a terephthalic acid hydrogenation catalyst. BACKGROUND

[0002] Terephthalic acid has important commercial value and is widely used in the preparation of various polyester polymers. A small amount of impurity p-carboxybenzaldehyde (4-CBA) in crude terephthalic acid (CTA) can affect the esterification performance of PTA. In industry, the main impurity 4-CBA (p-carboxybenzaldehyde) is usually hydrogenated under high temperature and high pressure in a palladium-based catalyst to generate p-toluic acid (p-TA) crystals, which are separated to obtain PTA.

[0003] The terephthalic acid hydrogenation refining reaction process is a first-order reaction, the reaction speed is fast, and it is difficult for the reactants to penetrate into the inside of the catalyst particles to react during the reaction process, so the distribution and dispersion of the metal palladium on the carrier have a great influence on the performance of the catalyst.

[0004] US 3,138,560 adds hydrogen peroxide to the impregnation solution to hydrolyze the water-soluble compound of Pd into an insoluble compound. However, since hydrogen peroxide itself also has oxidizing properties, it can oxidize the surface groups of the activated carbon, thereby changing the surface physical and chemical properties of the carrier, i.e., changing the surface group structure of the carrier, which has a strong uncertain negative impact and can damage other properties of the catalyst, such as catalyst life, selectivity, etc. SUMMARY

[0005] In view of the problems existing in the prior art, the present application provides a preparation method and application of a terephthalic acid hydrogenation catalyst. When the catalyst prepared by the preparation method provided by the present application is applied to the hydrogenation refining of crude terephthalic acid, the conversion rate of 4-CBA can be effectively improved.

[0006] In a first aspect, the present application provides a preparation method of a terephthalic acid hydrogenation catalyst, which comprises the following steps:

[0007] S1: subjecting a mixture containing a palladium source and a carrier to heat treatment in a first mixed gas atmosphere to obtain a heat-treated product,

[0008] S2: subjecting the heat-treated product of step S1 to reduction treatment in a second mixed gas atmosphere to obtain the terephthalic acid hydrogenation catalyst;

[0009] The first mixed gas comprises an inert gas and a C3-C10 monocarboxylic acid.

[0010] The present application can change the surface environment of the carrier, and facilitate the loading and dispersion of Pd on the surface of the carrier by heat treating the mixture containing a palladium source and a carrier in the presence of a mixed gas containing C3-C10 monocarboxylic acid.

[0011] In some embodiments, the first mixed gas contains C3-C8 monocarboxylic acid. In some embodiments, the first mixed gas contains C3-C5 monocarboxylic acid or C6-C8 monocarboxylic acid.

[0012] In some embodiments, the first mixed gas contains C3-C5 linear monocarboxylic acid or C6-C8 linear monocarboxylic acid. In some embodiments, the first mixed gas contains one or more of propionic acid, butyric acid, valeric acid, caproic acid, heptanoic acid and octanoic acid.

[0013] In some embodiments, the inert gas is selected from one or more of nitrogen, helium and argon.

[0014] In some embodiments, the molar ratio of monocarboxylic acid to inert gas in the first mixed gas is 1:0.5-1:5, for example 1:0.7, 1:1, 1:1.3, 1:1.5, 1:1.7, 1:2, 1:2.3, 1:2.5, 1:2.7, 1:3, 1:3.3, 1:3.5, 1:3.7, 1:4, 1:4.5 or any value therebetween. In some embodiments, the molar ratio of monocarboxylic acid to inert gas in the first mixed gas is 1:1-1:3.

[0015] In the present application, a too high molar ratio of monocarboxylic acid to inert gas can cause Pd to react with acidic substances in the atmosphere, resulting in a reduced loading amount. A too low molar ratio of monocarboxylic acid to inert gas can result in large pd particles and poor dispersion.

[0016] In some embodiments, the temperature of the heat treatment is 550℃-800℃, for example 570℃, 600℃, 630℃, 650℃, 670℃, 700℃, 730℃, 750℃, 770℃ or any value therebetween. In some embodiments, the temperature of the heat treatment is 600℃-750℃.

[0017] In the present application, a temperature of the heat treatment within the above range can sublimate Pd ions, promote the combination of Pd ions and the carrier, and a too high temperature can damage the structure of the carrier and cause the decomposition of organic acids in the atmosphere; a too low temperature can not sublimate Pd ions, which is not conducive to loading.

[0018] In some embodiments, the time of the heat treatment is 3h-20h, for example 6h, 8h, 10h, 12h, 14h, 16h or 18h. In some embodiments, the time of the heat treatment is 5h-15h.

[0019] In some embodiments, the second mixed gas comprises hydrogen and nitrogen. In some embodiments, the volume fraction of hydrogen in the second mixed gas is 1% to 20%, for example, 3%, 5%, 7%, 9%, 10%, 11%, 13%, 15%, 17%, 19%, or any value therebetween. In some embodiments, the volume fraction of hydrogen in the second mixed gas is 5% to 15%.

[0020] In some embodiments, the temperature of the reduction treatment is 100°C to 150°C, for example, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, or 145°C. In some embodiments, the time of the reduction treatment is 0.5h to 5h, for example, 1h, 2h, 3h, or 4h.

[0021] In some embodiments, the palladium source is selected from one or more of solid palladium sources. In some embodiments, the palladium source is selected from one or more of palladium chloride, palladium nitrate, and palladium acetate.

[0022] In some embodiments, the carrier is selected from silica. In some embodiments, the carrier is selected from mesoporous silica molecular sieves. In some embodiments, the carrier is selected from MCM-41 mesoporous molecular sieves.

[0023] In some embodiments, the mixture comprising the palladium source and the carrier is obtained by grinding mixing the palladium source and the carrier.

[0024] In some embodiments, the preparation of the first mixed gas comprises: preheating and gasifying the C3-C10 monocarboxylic acid, and then mixing with an inert gas to obtain the first mixed gas.

[0025] In some embodiments, the preheating temperature is 200°C to 300°C, for example, 210°C, 220°C, 230°C, 240°C, 255°C, 260°C, 270°C, 275°C, 290°C, or any value therebetween. In some embodiments, the preheating temperature is 250°C to 280°C.

[0026] In some embodiments, the mixed gas of the carboxylic acid (C3-C8) and N2 is mixed sufficiently in a preheater and a premixing tank before entering the tubular furnace.

[0027] In some embodiments, the C3-C10 monocarboxylic acid is preheated and gasified in the preheating gas, and then mixed with an inert gas such as nitrogen in a premixing tank.

[0028] In some embodiments, the preparation method of the terephthalic acid hydrogenation catalyst comprises the following specific steps:

[0029] (1) grinding a mixture of a palladium salt solid and a support, silica, to obtain material I;

[0030] (2) heat treating material I at 500-700°C to obtain material II, the heat treatment being carried out in an atmosphere comprising nitrogen and a carboxylic acid, said carboxylic acid being a C3-C8 saturated monocarboxylic acid;

[0031] (3) subjecting material II to a gas phase reduction to obtain said catalyst.

[0032] In a second aspect, the present application provides a terephthalic acid hydrogenation catalyst, said catalyst comprising a support and an active component, said active component comprising palladium, the mass content of said palladium being 0.5%-3% based on the mass of the catalyst, preferably, the dispersion of said palladium being 5%-20%.

[0033] In some embodiments, the mass content of said palladium is 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.7%, 2.0%, 2.3%, 2.5%, 2.7% or any value therebetween. In some embodiments, the mass content of said palladium is 0.5%-1.8%.

[0034] In some embodiments, the dispersion of said palladium is 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or any value therebetween. In some embodiments, the dispersion of said palladium is 8%-15%.

[0035] In some embodiments, the support is selected from silica. In some embodiments, the support is selected from mesoporous silica molecular sieves. In some embodiments, the support is selected from MCM-41 mesoporous molecular sieves.

[0036] In some embodiments, the method for preparing said terephthalic acid hydrogenation catalyst comprises the following steps:

[0037] S1: subjecting a mixture comprising a palladium source and a support to heat treatment in a first mixed gas atmosphere to obtain a heat-treated product,

[0038] S2: subjecting the heat-treated product of step S1 to reduction treatment in a second mixed gas atmosphere to obtain said terephthalic acid hydrogenation catalyst;

[0039] wherein said first mixed gas comprises an inert gas and a C3-C10 monocarboxylic acid.

[0040] In some embodiments, the first mixed gas comprises C3-C8 monocarboxylic acids. In some embodiments, the first mixed gas comprises C3-C5 monocarboxylic acids or C6-C8 monocarboxylic acids.

[0041] In some embodiments, the first mixed gas comprises C3-C5 straight-chain monocarboxylic acids or C6-C8 straight-chain monocarboxylic acids. In some embodiments, the first mixed gas comprises one or more of propionic acid, butyric acid, valeric acid, caproic acid, heptanoic acid, and octanoic acid.

[0042] In some embodiments, the inert gas is selected from one or more of nitrogen, helium, and argon.

[0043] In some embodiments, the molar ratio of monocarboxylic acid to inert gas in the first mixed gas is 1:0.5-1:5, such as 1:0.7, 1:1, 1:1.3, 1:1.5, 1:1.7, 1:2, 1:2.3, 1:2.5, 1:2.7, 1:3, 1:3.3, 1:3.5, 1:3.7, 1:4, 1:4.5, or any value therebetween. In some embodiments, the molar ratio of monocarboxylic acid to inert gas in the first mixed gas is 1:1-1:3.

[0044] In some embodiments, the temperature of the heat treatment is 550°C-800°C, such as 570°C, 600°C, 630°C, 650°C, 670°C, 700°C, 730°C, 750°C, 770°C, or any value therebetween. In some embodiments, the temperature of the heat treatment is 600°C-750°C.

[0045] In some embodiments, the time of the heat treatment is 3h-20h, such as 6h, 8h, 10h, 12h, 14h, 16h, or 18h. In some embodiments, the time of the heat treatment is 5h-15h.

[0046] In some embodiments, the second mixed gas comprises hydrogen and nitrogen. In some embodiments, the volume fraction of hydrogen in the second mixed gas is 1%-20%, such as 3%, 5%, 7%, 9%, 10%, 11%, 13%, 15%, 17%, 19%, or any value therebetween. In some embodiments, the volume fraction of hydrogen in the second mixed gas is 5%-15%.

[0047] In some embodiments, the temperature of the reduction treatment is 100°C-150°C, such as 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, or 145°C. In some embodiments, the time of the reduction treatment is 0.5h-5h, such as 1h, 2h, 3h, or 4h.

[0048] In some embodiments, the palladium source is selected from one or more of a solid palladium source. In some embodiments, the palladium source is selected from one or more of palladium chloride, palladium nitrate, and palladium acetate.

[0049] In some embodiments, the mixture comprising the palladium source and the support is obtained by grinding the palladium source and the support together.

[0050] In some embodiments, the first mixed gas is prepared by preheating a C3-C10 monocarboxylic acid and mixing the preheated C3-C10 monocarboxylic acid with an inert gas.

[0051] In some embodiments, the preheating temperature is 200-300°C, such as 210°C, 220°C, 230°C, 240°C, 255°C, 260°C, 270°C, 275°C, 290°C, or any value therebetween. In some embodiments, the preheating temperature is 250-280°C.

[0052] In some embodiments, the mixture of the carboxylic acid (C3-C8) and N2 is mixed thoroughly in a preheater and a premixing tank before entering the tube furnace.

[0053] In some embodiments, the C3-C10 monocarboxylic acid is preheated in a preheating gas and then mixed with an inert gas, such as nitrogen, in a premixing tank.

[0054] In some embodiments, the method for preparing the terephthalic acid hydrogenation catalyst comprises the following specific steps:

[0055] (1) grinding and mixing a palladium salt solid and a support, silicon dioxide, to obtain material I;

[0056] (2) heat treating material I at 500-700°C to obtain material II, the heat treatment atmosphere comprising nitrogen and a carboxylic acid, the carboxylic acid being a C3-C8 saturated monocarboxylic acid;

[0057] (3) gas phase reduction of material II to obtain the catalyst.

[0058] In a third aspect, the present application provides a terephthalic acid hydrogenation catalyst prepared by the preparation method of the first aspect or the terephthalic acid hydrogenation catalyst of the second aspect for use in the refining of crude terephthalic acid.

[0059] In a fourth aspect, the present application provides a method for refining crude terephthalic acid, which comprises using water as a solvent, using crude terephthalic acid containing 4-CBA and hydrogen as raw materials, and reacting in the presence of a terephthalic acid hydrogenation catalyst prepared by the preparation method of the first aspect or the terephthalic acid hydrogenation catalyst of the second aspect to remove 4-CBA from the crude terephthalic acid.

[0060] In some embodiments, the hydrofinishing reaction temperature may be 220°C-270°C.

[0061] In some embodiments, the hydrofinishing reaction pressure may be 7 bar to 12 bar.

[0062] In some embodiments, the hydrogenation reaction time is 120 min to 130 min.

[0063] In some embodiments, the reaction can be carried out in a batch mode or a continuous mode.

[0064] Beneficial technical effects of the present invention:

[0065] The catalyst provided by the invention is used for crude terephthalic acid refining reaction and has the characteristics of high catalyst activity and high 4-CBA conversion rate. DETAILED DESCRIPTION

[0066] To make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the following examples. The specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention in any way. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion about the concepts of the present disclosure. Such structures and technologies are also described in many publications.

[0067] The endpoints of the ranges and any values ​​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 endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0068] The present invention will be described in detail below through examples.

[0069] In the present invention, the weight percentage of palladium is measured by ICP-AES analysis.

[0070] In the present invention, the palladium dispersion is measured by hydrogen titration:

[0071]

[0072] Example 1

[0073] 1. Catalyst preparation

[0074] Mixing SiO2 support and Pd precursor: 10 g of mesoporous SiO2 with MCM-41 structure and 0.17 g of PdCl2 powder were thoroughly ground and mixed in a marver mortar to obtain the catalyst raw material.

[0075] Loading: The mixed catalyst raw material was placed in a tube furnace, first purged with 50 mL / min of N2 for 1 h to remove air. Then, a mixed gas with a propionic acid and N2 molar ratio of 1:2 (preparation method: propionic acid was injected at 0.055 mL into a preheater at 270°C for thorough vaporization, and then mixed with 33 mL / min of N2 in a premixing tank) was used as the loading atmosphere at a flow rate of 50 mL / min, and finally the reaction furnace was heated to 650°C and maintained for 7 h.

[0076] Reduction: The atmosphere in the tube furnace was replaced with N2\H2 mixed gas with a N2:H2 ratio of 9:1 (volume ratio) (H2 volume fraction of 10%), and the temperature was lowered to 110°C and maintained for 2 h. After reduction was completed, the catalyst was washed with deionized water for more than 3 times until the Cl element content in the washing liquid was less than 500 ppm, and then dried to obtain the Pd-SiO2 catalyst.

[0077] 2. Catalyst evaluation

[0078] 100 mL of a dynamic pressurized reaction kettle was added with the above catalyst 0.5 g and deionized water 60 mL, 4-CBA 2 g. Purged with nitrogen and pressurized to 10 bar, heated to 250°C, then started to pass into hydrogen to the pressure of 3 MPa (hydrogen partial pressure 2 MPa), the reaction temperature up to 270°C, the reaction time 2 h. After the reaction was completed, the 4-CBA conversion rate could reach 99.4% by chromatographic analysis.

[0079] Example 2

[0080] 1. Catalyst preparation

[0081] The catalyst preparation process was the same as in Example 1, except that the temperature of the reaction furnace during the loading process was 600°C.

[0082] 2. Catalyst evaluation

[0083] The same as in Example 1.

[0084] Example 3

[0085] 1. Catalyst preparation

[0086] The catalyst preparation process was the same as in Example 1, except that a mixed gas with a caprylic acid and N2 molar ratio of 1:2 was used instead of a mixed gas with a propionic acid and N2 molar ratio of 1:2.

[0087] 2. Catalyst evaluation

[0088] The same as Example 1.

[0089] Example 4

[0090] 1. Catalyst preparation

[0091] The catalyst was prepared in the same manner as in Example 1, except that the temperature of the reduction treatment was 150°C.

[0092] 2. Catalyst evaluation

[0093] The same as Example 1.

[0094] Example 5

[0095] 1. Catalyst preparation

[0096] The catalyst was prepared in the same manner as in Example 1, except that in the reduction treatment, N2:H2mixed gas (H2volume fraction: 1%) having a N2:H2ratio of 99:1 was used instead of N2:H2mixed gas having a N2:H2ratio of 9:1.

[0097] 2. Catalyst evaluation

[0098] The same as Example 1.

[0099] Example 6

[0100] 1. Catalyst preparation

[0101] The catalyst was prepared in the same manner as in Example 1, except that in the reduction treatment, N2:H2mixed gas (H2volume fraction: 20%) having a N2:H2ratio of 8:2 was used instead of N2:H2mixed gas having a N2:H2ratio of 9:1.

[0102] 2. Catalyst evaluation

[0103] The same as Example 1.

[0104] Example 7

[0105] 1. Catalyst preparation

[0106] The catalyst was prepared in the same manner as in Example 1, except that mixed gas having a propionic acid:N2molar ratio of 1:4 was used instead of mixed gas having a propionic acid:N2molar ratio of 1:2.

[0107] 2. Catalyst evaluation

[0108] The same as Example 1.

[0109] Example 8

[0110] 1. Catalyst preparation

[0111] The catalyst preparation process is the same as that of Example 1, except that a mixture of propionic acid and N2 with a molar ratio of 1:0.5 is used instead of a mixture of propionic acid and N2 with a molar ratio of 1:2.

[0112] 2. Catalyst evaluation

[0113] Same as Example 1.

[0114] Comparative Example 1

[0115] 1. Catalyst preparation

[0116] The catalyst preparation process was the same as in Example 1, except that pure N2 gas was used to replace the mixture of propionic acid and N2 with a molar ratio of 1:2.

[0117] 2. Catalyst evaluation

[0118] Same as Example 1.

[0119] Comparative Example 2

[0120] 1. Catalyst preparation

[0121] The catalyst preparation process is the same as that of Example 1, except that a mixture of NH3 and N2 in a molar ratio of 1:2 is used to replace a mixture of propionic acid and N2 in a molar ratio of 1:2.

[0122] 2. Catalyst evaluation

[0123] Same as Example 1.

[0124] Comparative Example 3

[0125] 1. Catalyst preparation

[0126] The catalyst preparation process is the same as that of Example 1, except that a mixture of acrylic acid and N2 in a molar ratio of 1:2 is used to replace a mixture of propionic acid and N2 in a molar ratio of 1:2.

[0127] 2. Catalyst evaluation

[0128] Same as Example 1.

[0129] Comparative Example 4

[0130] 1. Catalyst preparation

[0131] The catalyst preparation process is the same as that of Example 1, except that a mixture of hydrogen chloride and N2 in a molar ratio of 1:2 is used instead of a mixture of propionic acid and N2 in a molar ratio of 1:2.

[0132] 2. Catalyst evaluation

[0133] Same as Example 1.

[0134] Comparative Example 5

[0135] 1. Catalyst preparation

[0136] The catalyst was prepared in the same manner as in Example 1, except that a mixed gas of formic acid and N2in a molar ratio of 1:2 was used instead of a mixed gas of propionic acid and N2in a molar ratio of 1:2.

[0137] 2. Catalyst evaluation

[0138] The same as in Example 1.

[0139] Comparative Example 6

[0140] 1. Catalyst preparation

[0141] The catalyst was prepared in the same manner as in Example 1, except that a mixed gas of acetic acid and N2in a molar ratio of 1:2 was used instead of a mixed gas of propionic acid and N2in a molar ratio of 1:2.

[0142] 2. Catalyst evaluation

[0143] The same as in Example 1.

[0144] Comparative Example 7

[0145] 1. Catalyst preparation

[0146] The catalyst was prepared in the same manner as in Example 1, except that a mixed gas of dodecanoic acid and N2in a molar ratio of 1:2 was used instead of a mixed gas of propionic acid and N2in a molar ratio of 1:2.

[0147] 2. Catalyst evaluation

[0148] The same as in Example 1.

[0149] Comparative Example 8

[0150] 1. Catalyst preparation

[0151] The catalyst was prepared in the same manner as in Example 1, except that a mixed gas of oxalic acid and N2in a molar ratio of 1:2 was used instead of a mixed gas of propionic acid and N2in a molar ratio of 1:2.

[0152] 2. Catalyst evaluation

[0153] The same as in Example 1.

[0154] The content and dispersion of the active component, palladium, of the catalysts in each of the examples and comparative examples, and the evaluation results of the catalysts using the above-mentioned activity evaluation conditions are shown in Table 1.

[0155] Table 1

[0156]

[0157]

[0158] As can be seen from Table 1, after treating the catalyst raw material with the mixed gas containing the monobasic carboxylic acid defined in the present application, the conversion rate of 4-CBA of the prepared catalyst can be effectively improved.

[0159] The preferred embodiments of the present application are described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including that each technical feature is combined in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application and belong to the protection scope of the present application.

Claims

1. A method for preparing a terephthalic acid hydrogenation catalyst, comprising the following steps: S1: subjecting a mixture comprising a palladium source and a carrier to a heat treatment in a first mixed gas atmosphere to obtain a heat-treated product, S2: subjecting the heat-treated product of step S1 to a reduction treatment in a second mixed gas atmosphere to obtain the terephthalic acid hydrogenation catalyst; wherein the first mixed gas comprises an inert gas and a C3-C10 monocarboxylic acid.

2. The production method according to claim 1, characterized by, the first mixed gas comprises a C3-C8 monocarboxylic acid, preferably one or more of propionic acid, butyric acid, valeric acid, caproic acid, heptanoic acid and octanoic acid; and / or the inert gas is selected from one or more of nitrogen, helium and argon.

3. The production method according to claim 1 or 2, characterized by, In the first mixed gas, the molar ratio of the monocarboxylic acid to the inert gas is 1:0.5-1:5, preferably 1:1-1:

3.

4. The production method according to any one of claims 1 to 3, characterized by, The temperature of the heat treatment is 550-800℃, preferably 600-750℃; the time of the heat treatment is 3-20h, preferably 5-15h.

5. The production method according to any one of claims 1 to 4, characterized by, The second mixed gas comprises hydrogen and nitrogen, preferably in the second mixed gas, the volume fraction of hydrogen is 1-20%, preferably 5-15%; and / or The temperature of the reduction treatment is 100-150℃, and the time of the reduction treatment is 0.5-5h.

6. The production method according to any one of claims 1 to 5, characterized by, The palladium source is selected from one or more of solid palladium sources, preferably the palladium source is selected from one or more of palladium chloride, palladium nitrate and palladium acetate; and / or The carrier is selected from silica, preferably mesoporous silica molecular sieve, more preferably MCM-41 mesoporous molecular sieve.

7. The production method according to any one of claims 1 to 6, characterized by, The C3-C10 monocarboxylic acid is preheated and gasified, and then mixed with the inert gas to obtain the first mixed gas, preferably the preheating temperature is 200-300℃, preferably 250-280℃. 8.A terephthalic acid hydrogenation catalyst prepared by the preparation method according to any one of claims 1-7, preferably the catalyst comprises a carrier and an active component, the active component comprises palladium, and the mass content of the palladium is 0.5-3%, preferably 0.8-1.5%, based on the mass of the catalyst; and / or The dispersion of palladium is 5-20%, preferably 8-15%. 9.The terephthalic acid hydrogenation catalyst prepared by the preparation method according to any one of claims 1-7 or the terephthalic acid hydrogenation catalyst according to claim 8 is used for crude terephthalic acid hydrogenation refining. 10.A method for refining crude terephthalic acid, comprising reacting crude terephthalic acid containing 4-CBA and hydrogen as raw materials in the presence of a terephthalic acid hydrogenation catalyst prepared by the preparation method according to any one of claims 1-7 or the terephthalic acid hydrogenation catalyst according to claim 8, with water as solvent, to remove 4-CBA in the crude terephthalic acid.

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