A cta hydrofining catalyst, its preparation method and application

Abstract

This invention relates to the field of catalyst technology, and provides a CTA hydrorefining catalyst, its preparation method, and its application. The catalyst preparation method includes: loading an active component onto a support using a supported liquid, followed by reduction treatment to obtain the catalyst; the supported liquid includes an active component precursor and a surfactant. The catalyst preparation process is simple and controllable, and its application in the CTA hydrorefining reaction can effectively improve the conversion rate of 4-CBA.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, and more specifically, to a CTA hydrorefining catalyst, its preparation method, and its application. Background Technology

[0002] Purified terephthalic acid (PTA) is an important chemical raw material, mainly used in the production of polyesters. Its preparation process primarily includes a PX oxidation step and a CTA hydrogenation refining step. The PX oxidation step involves numerous side reactions, resulting in the crude terephthalic acid (CTA) obtained from the oxidation process containing byproducts such as methylbenzaldehyde (TALD), p-methylbenzoic acid (PT acid), and p-carboxybenzaldehyde (4-CBA). Among these, 4-CBA significantly affects the melting point of polyesters, harming product quality. The 4-CBA content is a crucial indicator of PTA quality; therefore, the CTA hydrogenation refining process must remove 4-CBA. Since the molecular structure of 4-CBA is similar to that of terephthalic acid, it can form a eutectic with terephthalic acid, which is difficult to remove by conventional physical methods. Therefore, in the CTA hydrogenation purification step, a CTA hydrogenation purification catalyst is used to catalyze the reaction, so that 4-CBA reacts with H2 under the action of the CTA hydrogenation purification catalyst, reducing its aldehyde group to a methyl group, thereby generating the water-soluble substance PT acid and removing it.

[0003] However, the existing CTA hydrorefining catalysts do not perform well in the catalytic conversion of 4-CBA, and the conversion rate of 4-CBA is low. Summary of the Invention

[0004] The purpose of this invention is to provide a CTA hydrorefining catalyst and its preparation method, so as to solve the technical problem of low 4-CBA conversion rate of existing CTA hydrorefining catalysts in the prior art.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] In a first aspect, the present invention provides a method for preparing a catalyst, comprising: loading an active component onto a support using a supporting liquid, and then subjecting it to a reduction treatment to obtain the catalyst; wherein the supporting liquid comprises an active component precursor and a surfactant.

[0007] In this invention, the addition of surfactants to the supported liquid can promote the dispersion of active components, improve the utilization rate of active components, and thus enhance the catalytic effect of the catalyst.

[0008] According to some embodiments of the present invention, the surfactant includes anionic surfactants and / or tertiary amine oxide surfactants.

[0009] According to some embodiments of the present invention, the surfactant includes anionic surfactants and tertiary amine oxide surfactants.

[0010] In this invention, the combined use of anionic surfactants and tertiary amine oxide surfactants can further improve the dispersion effect of the active components.

[0011] According to some embodiments of the present invention, the mass ratio of the anionic surfactant to the tertiary amine oxide surfactant is 1:3 to 3:1.

[0012] According to some embodiments of the present invention, the tertiary amine oxide surfactant has the structural formula R1N(R2)2O, wherein R1 is selected from C 10 ~C 20 Alkyl group, R2 is selected from C1-C5 alkyl groups and C1-C5 alkyl groups substituted with hydroxyl groups.

[0013] According to some embodiments of the present invention, the tertiary amine oxide surfactant includes at least one of tetradecyl dihydroxyethyl amine oxide, hexadecyl dihydroxyethyl amine oxide, octadecyl dihydroxyethyl amine oxide, octadecyl dimethyl amine oxide, and hexadecyl dimethyl amine oxide, preferably octadecyl dihydroxyethyl amine oxide.

[0014] According to some embodiments of the present invention, the anionic surfactant includes at least one of alkyl sulfate alkali metal salts and alkylbenzene sulfonates.

[0015] According to some embodiments of the present invention, the alkyl sulfate alkali metal salt has 10 to 20 alkyl carbons.

[0016] According to some embodiments of the present invention, the alkyl sulfate alkali metal salt includes at least one of sodium decyl sulfate, sodium undecyl sulfate, sodium dodecyl sulfate, sodium dodecyl hydrogen sulfate, sodium tridecyl hydrogen sulfate, and sodium octadecyl sulfate.

[0017] According to some embodiments of the present invention, the alkylbenzene sulfonate includes at least one of sodium dodecylbenzene sulfonate, potassium dodecylbenzene sulfonate, calcium dodecylbenzene sulfonate, magnesium dodecylbenzene sulfonate, tetrabutyltrifluoromethanesulfonate, and hexadecyltrimethyl-p-toluenesulfonate, such as sodium dodecylbenzene sulfonate.

[0018] According to some embodiments of the present invention, the active component includes Pd.

[0019] According to some embodiments of the present invention, the active component precursor includes a Pd-containing compound, such as chloropalladium acid.

[0020] According to some embodiments of the present invention, the support is an FAU-configured molecular sieve.

[0021] FAU molecular sieves generally include X-type molecular sieves and Y-type molecular sieves.

[0022] According to some embodiments of the present invention, the carrier is an X-type molecular sieve.

[0023] According to some embodiments of the present invention, the SiO2 / Al2O3 (molar ratio) of the carrier is 2.2 to 3.0.

[0024] According to some embodiments of the present invention, the SiO2 / Al2O3 (molar ratio) of the carrier is 2.4 to 2.8.

[0025] According to some embodiments of the present invention, the loading of the active component Pd in ​​the catalyst is 0.05 to 5 wt%.

[0026] According to some embodiments of the present invention, the loading of the active component Pd in ​​the catalyst is 0.08 to 2 wt%.

[0027] According to some embodiments of the present invention, the loading of the active component Pd in ​​the catalyst is 0.1 to 1 wt%.

[0028] According to some embodiments of the present invention, the mass ratio of the surfactant to the active component is (5-20):1.

[0029] According to some embodiments of the present invention, the mass ratio of the surfactant to the active component is (5-10):1.

[0030] According to some embodiments of the present invention, the carrier is pretreated, the pretreatment including treatment with NaH2PO4 solution and / or treatment with NaOH solution.

[0031] In this invention, pretreating the support with NaH2PO4 solution and / or NaOH solution is beneficial for increasing the pore volume and specific surface area of ​​the molecular sieve support, thereby improving the catalytic performance of the catalyst. The NaH2PO4 solution and NaOH solution can generally be aqueous solutions, and the treatment process can employ common methods that ensure sufficient contact between the support and the treatment solution, such as immersing the support in the solution.

[0032] According to some embodiments of the present invention, the pretreatment includes treatment with NaH2PO4 solution and treatment with NaOH solution.

[0033] According to some embodiments of the present invention, the concentration of the NaH2PO4 solution is 0.2–2 wt%.

[0034] According to some embodiments of the present invention, the treatment time with NaH2PO4 solution is 30 to 50 minutes.

[0035] According to some embodiments of the present invention, the concentration of the NaOH solution is 0.01 to 0.05 wt%.

[0036] According to some embodiments of the present invention, the treatment time with NaOH solution is 20 to 30 minutes.

[0037] According to some embodiments of the present invention, the temperature of the reduction treatment is 40-100°C, the reducing gas is H2, and the reduction time is 1-2 hours.

[0038] Secondly, the present invention provides a catalyst prepared by the preparation method described in the first aspect.

[0039] Thirdly, the present invention provides the application of the catalyst described in the second aspect in the CTA hydrorefining reaction.

[0040] According to some embodiments of the present invention, the temperature of the CTA hydrogenation refining reaction is 250–300°C, the pressure is 7–12 bar, and the time is 120–130 min.

[0041] The beneficial effects of this invention are at least as follows:

[0042] The preparation method of the CTA hydrorefining catalyst provided by this invention is simple and controllable, and its application in the CTA hydrorefining reaction can effectively improve the conversion rate of 4-CBA. Detailed Implementation

[0043] To make the technical problem to be solved, the technical solution, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely for illustrating this patent and do not limit the scope of protection of this invention in any way.

[0044] Unless otherwise defined, the technical terms used in the following embodiments have the same meaning as commonly understood by those skilled in the art. Unless otherwise specified, the reagents used in the following embodiments are conventional biochemical reagents; the raw materials, instruments, and equipment used in the following embodiments can all be obtained commercially or by existing methods; unless otherwise specified, the reagent dosages are those used in routine experimental operations; unless otherwise specified, the experimental methods are conventional methods.

[0045] Example 1

[0046] The catalyst is prepared as follows:

[0047] Molecular sieve pretreatment: Take 10g of type X molecular sieve, wash with deionized water, and dry. First, soak the sieve in 500mL of 0.5wt% NaH2PO4 solution at room temperature for 30min, filter, and wash with deionized water at least 3 times until the pH of the washing solution is neutral; then soak the molecular sieve in 500mL of 0.02wt% NaOH solution at room temperature for 20min, filter, and wash with deionized water at least 3 times until the pH of the washing solution is neutral; finally, dry in a muffle furnace at 480℃ for 8h.

[0048] Preparation of the loading solution: Take 0.3g of chloropalladium acid (Pd content 18wt%), add 4g of deionized water, and stir thoroughly at room temperature for 1h; then add 0.2g of sodium dodecyl sulfate and 0.2g of octadecyl dihydroxyethylamine oxide, and stir for 20min.

[0049] Loading: The pretreated molecular sieve and the loading liquid are thoroughly mixed and shaken until the loading liquid is fully absorbed; then the mixture is placed in a dryer for 24 hours for aging.

[0050] Reduction: The aged catalyst precursor was placed in a tube furnace and reduced completely at 90°C for 1 hour using 5% H2 (Ar gas was used as the inert gas). After reduction, the catalyst was washed with deionized water at least three times until the Cl content in the washing solution was below 500 ppm, and then dried and stored.

[0051] Example 2

[0052] The catalyst is prepared as follows:

[0053] Molecular sieve pretreatment: Take 10g of type X molecular sieve, wash with deionized water, and dry. First, soak the sieve in 500mL of 1wt% NaH2PO4 solution at room temperature for 40min, filter, and wash with deionized water at least 3 times until the pH of the washing solution is neutral; then soak the molecular sieve in 500mL of 0.03wt% NaOH solution at room temperature for 30min, filter, and wash with deionized water at least 3 times until the pH of the washing solution is neutral; finally, dry in a muffle furnace at 480℃ for 8h.

[0054] Preparation of the loading solution: Take 0.5g of chloropalladium acid (Pd content 18wt%), add 4g of deionized water, and stir thoroughly at room temperature for 1h; then add 0.6g of sodium dodecyl sulfate and 0.2g of octadecyl dihydroxyethylamine oxide, and stir for 20min.

[0055] Loading: The pretreated molecular sieve and the loading liquid are thoroughly mixed and shaken until the loading liquid is fully absorbed; then the mixture is placed in a dryer for 24 hours for aging.

[0056] Reduction: The aged catalyst precursor was placed in a tube furnace and reduced completely at 70°C for 2 hours using 5% H2 (Ar gas was used as the inert gas). After reduction, the catalyst was washed with deionized water at least three times until the Cl content in the washing solution was below 500 ppm, and then dried and stored.

[0057] Example 3

[0058] The catalyst is prepared as follows:

[0059] Molecular sieve pretreatment: Take 10g of type X molecular sieve, wash with deionized water, and dry. First, soak the sieve in 500mL of 0.3wt% NaH2PO4 solution at room temperature for 50min, filter, and wash with deionized water at least 3 times until the pH of the washing solution is neutral; then soak the molecular sieve in 500mL of 0.05wt% NaOH solution at room temperature for 20min, filter, and wash with deionized water at least 3 times until the pH of the washing solution is neutral; finally, dry in a muffle furnace at 480℃ for 8h.

[0060] Preparation of the loading solution: Take 0.1g of chloropalladium acid (Pd content 18wt%), add 4g of deionized water, and stir thoroughly at room temperature for 1h; then add 0.05g of sodium dodecyl sulfate and 0.1g of octadecyl dihydroxyethylamine oxide, and stir for 20min.

[0061] Loading: The pretreated molecular sieve and the loading liquid are thoroughly mixed and shaken until the loading liquid is fully absorbed; then the mixture is placed in a dryer for 24 hours for aging.

[0062] Reduction: The aged catalyst precursor was placed in a tube furnace and reduced completely at 90°C for 1 hour using 5% H2 (Ar gas was used as the inert gas). After reduction, the catalyst was washed with deionized water at least three times until the Cl content in the washing solution was below 500 ppm, and then dried and stored.

[0063] Example 4

[0064] The catalyst was prepared according to Example 1, except for the molecular sieve pretreatment step.

[0065] Molecular sieve pretreatment: Take 10g of type X molecular sieve, wash with deionized water, and dry. Soak in 500mL of 0.5wt% NaH2PO4 solution at room temperature for 30min, filter, wash with deionized water at least 3 times until the pH of the washing solution is neutral; then dry in a muffle furnace at 480℃ for 8h.

[0066] Example 5

[0067] The catalyst was prepared according to Example 1, except for the molecular sieve pretreatment step.

[0068] Molecular sieve pretreatment: Take 10g of type X molecular sieve, wash with deionized water, and dry. Soak the molecular sieve in 500mL of 0.02wt% NaOH solution at room temperature for 20min, filter, wash with deionized water more than 3 times until the pH of the washing solution is neutral; then dry in a muffle furnace at 480℃ for 8h.

[0069] Example 6

[0070] The catalyst was prepared according to Example 1, except for the molecular sieve pretreatment step.

[0071] Molecular sieve pretreatment: Take 10 grams of X-type molecular sieve, wash it with deionized water more than 3 times until the pH of the washing solution is neutral, and then dry it in a muffle furnace at 480℃ for 8 hours.

[0072] Example 7

[0073] The catalyst was prepared according to Example 6, except that 0.2 g of sodium dodecyl sulfate and 0.2 g of octadecyl dihydroxyethylamine oxide in the supported solution were replaced with 0.4 g of sodium dodecyl sulfate.

[0074] Example 8

[0075] The catalyst was prepared according to Example 6, except that 0.2 g of sodium dodecyl sulfate and 0.2 g of octadecyl dihydroxyethylamine oxide in the supported solution were replaced with 0.4 g of octadecyl dihydroxyethylamine oxide.

[0076] Example 9

[0077] The catalyst was prepared according to Example 6, except that 0.2 g of sodium dodecyl sulfate and 0.2 g of octadecyl dihydroxyethylamine oxide in the supported solution were replaced with 0.2 g of sodium dodecylbenzenesulfonate and 0.2 g of octadecyl dihydroxyethylamine oxide.

[0078] Example 10

[0079] The catalyst was prepared according to Example 6, except that 0.2 g of sodium dodecyl sulfate and 0.2 g of octadecyl dihydroxyethylamine oxide in the supported solution were replaced with 0.2 g of sodium decyl sulfate and 0.2 g of octadecyl dihydroxyethylamine oxide.

[0080] Example 11

[0081] The catalyst was prepared according to Example 6, except that 0.2 g of sodium dodecyl sulfate and 0.2 g of octadecyl dihydroxyethylamine oxide in the supported solution were replaced with 0.2 g of sodium tridecyl hydrogen sulfate and 0.2 g of octadecyl dihydroxyethylamine oxide.

[0082] Example 12

[0083] The catalyst was prepared according to Example 6, except that 0.2 g of sodium dodecyl sulfate and 0.2 g of octadecyl dihydroxyethylamine oxide in the supported solution were replaced with 0.2 g of sodium dodecyl sulfate and 0.2 g of hexadecyl dimethylamine oxide.

[0084] Example 13

[0085] The catalyst preparation method is the same as in Example 4, except that: after aging, the aged catalyst precursor is treated with 500 mL of 0.02 wt% NaOH solution at room temperature for 10 min, filtered, washed with deionized water more than 3 times until the pH of the washing solution is neutral, and then the catalyst precursor is dried before proceeding with the reduction step.

[0086] Example 14

[0087] The catalyst preparation method is the same as in Example 5, except that: after aging, the aged catalyst precursor is treated with 500 mL of 0.5 wt% NaH2PO4 solution at room temperature for 10 min, filtered, washed with deionized water more than 3 times until the pH of the washing solution is neutral, and then the catalyst precursor is dried before proceeding with the reduction step.

[0088] Example 15

[0089] The catalyst was prepared according to Example 1, except that the X-type molecular sieve was replaced with a Y-type molecular sieve.

[0090] Comparative Example 1

[0091] The catalyst is prepared as follows:

[0092] Molecular sieve pretreatment: Take 10 grams of X-type molecular sieve, wash it with deionized water more than 3 times until the pH of the washing solution is neutral, and then dry it in a muffle furnace at 480℃ for 8 hours.

[0093] Preparation of the loading solution: Take 0.03 g of chloropalladium acid, add 4 g of deionized water, and stir thoroughly at room temperature for 1 h.

[0094] Loading: The pretreated molecular sieve and the loading liquid are thoroughly mixed and shaken until the loading liquid is fully absorbed; then the mixture is placed in a dryer for 24 hours for aging.

[0095] Reduction: The aged catalyst precursor was placed in a tube furnace and reduced completely at 90°C for 1 hour using 5% H2 (Ar gas was used as the inert gas). After reduction, the catalyst was washed with deionized water at least three times until the Cl content in the washing solution was below 500 ppm, and then dried and stored.

[0096] Catalyst performance evaluation

[0097] The evaluation method is as follows:

[0098] 0.2 g of catalyst, 48 mL of deionized water, and 12 mL of 4-CBA were added to a 100 mL dynamically pressurized reactor. The reactor was purged with nitrogen and pressurized to 10 bar. After heating to 250 °C, hydrogen gas was introduced, and the reaction temperature was raised to a maximum of 270 °C for 2 hours. The conversion rate of 4-CBA was determined by chromatographic analysis after the reaction was completed.

[0099] The evaluation results are shown in the table below:

[0100]

[0101]

[0102] A comparison of the catalysts from Examples 1, 4-6, and 13-14 shows that pretreatment of the support with NaH2PO4 solution and / or NaOH solution can improve the 4-CBA conversion rate of the catalyst. Furthermore, the catalyst prepared by sequentially pretreatment with both solutions exhibits better catalytic performance than the catalyst prepared by pretreatment with only one solution.

[0103] By comparing the catalysts in Examples 6-12, it can be seen that the use of both anionic and tertiary amine oxide surfactants in the supported liquid can result in a higher 4-CBA conversion rate compared to using only one of these surfactants.

[0104] A comparison of the catalysts in Examples 1 and 15 shows that using an X-type molecular sieve as the support can result in better catalytic performance compared to using a Y-type molecular sieve.

[0105] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A method for preparing a catalyst, characterized in that, include: The active component is loaded onto a support using a supporting liquid, and then reduced to obtain the catalyst. The supported liquid includes an active component precursor and a surfactant; The carrier undergoes pretreatment, which includes treatment with NaH2PO4 solution and treatment with NaOH solution; after the NaH2PO4 solution treatment is completed, the carrier is washed until neutral. The surfactants include anionic surfactants and oxidized tertiary amine surfactants; The carrier is an X-type molecular sieve.

2. The preparation method according to claim 1, characterized in that, The mass ratio of the anionic surfactant to the tertiary amine oxide surfactant is 1:3 to 3:1; And / or, the anionic surfactant includes at least one of alkali metal alkyl sulfates and alkylbenzene sulfonates; And / or, the tertiary amine oxide surfactant has the structural formula R1N(R2)2O, wherein R1 is selected from C 10 ~C 20 Alkyl group, R2 is selected from C1-C5 alkyl groups and C1-C5 alkyl groups substituted with hydroxyl groups.

3. The preparation method according to claim 1, characterized in that, The tertiary amine oxide surfactant includes at least one of tetradecyl dihydroxyethyl amine oxide, hexadecyl dihydroxyethyl amine oxide, octadecyl dihydroxyethyl amine oxide, octadecyl dimethyl amine oxide, and hexadecyl dimethyl amine oxide.

4. The preparation method according to claim 1, characterized in that, The tertiary amine oxide surfactant includes octadecyl dihydroxyethyl amine oxide.

5. The preparation method according to claim 2, characterized in that, The alkyl sulfate alkali metal salt has 10 to 20 alkyl carbons; And / or, the alkylbenzene sulfonate includes at least one of sodium dodecylbenzene sulfonate, potassium dodecylbenzene sulfonate, calcium dodecylbenzene sulfonate, magnesium dodecylbenzene sulfonate, tetrabutyltrifluoromethanesulfonate, and hexadecyltrimethyl-p-toluenesulfonate.

6. The preparation method according to claim 2, characterized in that, The alkyl sulfate alkali metal salt includes at least one of sodium decyl sulfate, sodium undecyl sulfate, sodium dodecyl sulfate, sodium dodecyl hydrogen sulfate, sodium tridecyl hydrogen sulfate, and sodium octadecyl sulfate.

7. The preparation method according to any one of claims 1-6, characterized in that, The active component includes Pd; And / or, the active component precursor includes a Pd-containing compound.

8. The preparation method according to any one of claims 1-6, characterized in that, The SiO2 / Al2O3 ratio of the support is 2.2 to 3.

0.

9. The preparation method according to claim 8, characterized in that, The SiO2 / Al2O3 ratio of the carrier is 2.4 to 2.

8.

10. The preparation method according to claim 7, characterized in that, The loading of the active component Pd in ​​the catalyst is 0.05 to 5 wt%.

11. The preparation method according to any one of claims 1-6, characterized in that, The mass ratio of the surfactant to the active component is (5-20):

1.

12. The preparation method according to any one of claims 1-6, characterized in that, The concentration of the NaH2PO4 solution is 0.2–2 wt%; And / or, the treatment time with NaH2PO4 solution is 30–50 min; And / or, the concentration of the NaOH solution is 0.01–0.05 wt%; And / or, the treatment time with NaOH solution is 20 to 30 minutes.

13. The preparation method according to any one of claims 1-6, characterized in that, The reduction treatment is performed at a temperature of 40–100°C, using H2 as the reducing gas, and for a time of 1–2 hours.

14. A catalyst prepared by the preparation method according to any one of claims 1-13.

15. The application of the catalyst according to claim 14 in the CTA hydrorefining reaction.

Images