CTA hydrofining catalyst as well as preparation method and application thereof

Abstract

The invention relates to the technical field of catalysts, and provides a CTA hydrofining catalyst and a preparation method and application thereof. The preparation method of the catalyst comprises the following steps: loading an active component on a carrier by using a loading liquid, and then carrying out reduction treatment to obtain the catalyst, the load liquid comprises an active component precursor and a surfactant. The preparation process of the catalyst is simple and controllable, and the conversion rate of 4-CBA can be effectively improved when the catalyst is used in a CTA hydrofining reaction.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and more specifically, to a CTA hydrorefining catalyst and a preparation method and application thereof. Background Art

[0002] Purified Terephthalic Acid (PTA) is an important chemical raw material, which can be mainly used to produce polyester. Its preparation process mainly includes PX oxidation step and CTA hydrogenation refining step. The PX oxidation step is accompanied by a large number of side reactions, resulting in the crude terephthalic acid (CTA) obtained from the oxidation process containing by-products such as methylbenzaldehyde (TALD), p-methylbenzoic acid (PT acid) and p-carboxybenzaldehyde (4-carboxybenzaldehyde, 4-CBA). Among them, 4-CBA will have a great impact on the melting point of polyester and endanger the quality of the product. The content of 4-CBA is an important indicator of PTA quality, so 4-CBA must be removed through the CTA hydrogenation refining process. 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 hydrorefining step, a CTA hydrorefining catalyst is used to catalyze the reaction, so that 4-CBA reacts with H under the action of the CTA hydrorefining catalyst. 2 A reduction reaction occurs, reducing its own aldehyde group to a methyl group, thereby generating a water-soluble substance, PT acid, and removing it.

[0003] However, the catalytic conversion effect of existing CTA hydrorefining catalysts on 4-CBA is not ideal, and the conversion rate of 4-CBA is low. Summary of the invention

[0004] The object of the present invention is to provide a CTA hydrorefining catalyst and a preparation method thereof, 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 object, the technical solution adopted by the present invention is:

[0006] In a first aspect, the present invention provides a method for preparing a catalyst, comprising: using a loading liquid to load an active component on a carrier, and then performing a reduction treatment to obtain the catalyst; the loading liquid comprises an active component precursor and a surfactant.

[0007] In the present invention, adding a surfactant to the loading liquid can promote the dispersion of the active components, improve the utilization rate of the active components, and thus improve the catalytic effect of the catalyst.

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

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

[0010] In the present invention, the combined use of anionic surfactants and tertiary amine oxide surfactants can further improve the dispersing 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 structural formula of the tertiary amine oxide surfactant is R 1 N(R 2 ) 2 O, where R 1 Selected from C 10 ~C 20 Alkyl, R 2 Selected from C 1 ~C 5 Alkyl, hydroxy substituted C 1 ~C 5 alkyl.

[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 an alkali metal alkyl sulfate and an alkylbenzene sulfonate.

[0015] According to some embodiments of the present invention, the alkali metal alkyl sulfate has an alkyl carbon number of 10-20.

[0016] According to some embodiments of the present invention, the alkali metal alkyl sulfate 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, tetrabutylammonium trifluoromethanesulfonate, and hexadecyltrimethylammonium p-toluenesulfonate, such as sodium dodecylbenzene sulfonate.

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

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

[0020] According to some embodiments of the present invention, the carrier is a FAU-configuration 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 SiO 2 / Al 2 O 3 (molar ratio) is 2.2 to 3.0.

[0024] According to some embodiments of the present invention, the SiO 2 / Al 2 O 3 (molar ratio) is 2.4 to 2.8.

[0025] According to some embodiments of the present invention, the loading amount 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 amount of the active component Pd in ​​the catalyst is 0.08-2 wt %.

[0027] According to some embodiments of the present invention, the loading amount 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, and the pretreatment comprises: using NaH 2 PO 4 Solution treatment and / or treatment with NaOH solution.

[0031] In the present invention, NaH 2 PO 4The pretreatment of the carrier with NaOH solution and / or NaOH solution is beneficial to increase the pore volume and specific surface area of ​​the molecular sieve carrier, thereby improving the catalytic performance of the catalyst. 2 PO 4 The solution and NaOH solution can generally be aqueous solutions, and the treatment process can adopt common treatment methods such as immersing the carrier in the solution so that the carrier and the treatment solution can be fully contacted.

[0032] According to some embodiments of the present invention, the pretreatment comprises: using NaH 2 PO 4 Solution treatment and treatment with NaOH solution.

[0033] According to some embodiments of the present invention, the NaH 2 PO 4 The concentration of the solution is 0.2-2 wt%.

[0034] According to some embodiments of the present invention, NaH 2 PO 4 The solution treatment time is 30 to 50 minutes.

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

[0036] According to some embodiments of the present invention, the treatment time with the 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, and the reducing gas is H 2 , the reduction time is 1 to 2 hours.

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

[0039] In a third aspect, the present invention provides use of the catalyst described in the second aspect in a CTA hydrotreating reaction.

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

[0041] The beneficial effects of the present invention are at least:

[0042] The preparation method of the CTA hydrorefining catalyst provided by the present invention is simple and controllable, and using the catalyst in the CTA hydrorefining reaction can effectively improve the conversion rate of 4-CBA. DETAILED DESCRIPTION

[0043] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain this patent in detail and do not limit the scope of protection of the present invention in any way.

[0044] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the raw materials, instruments and equipment used in the following examples, etc., can all be purchased on the market or can be obtained by existing methods; the reagent amounts, unless otherwise specified, are the reagent amounts used in conventional experimental operations; the experimental methods, unless otherwise specified, are all conventional methods.

[0045] Example 1

[0046] The preparation method of the catalyst is as follows:

[0047] Molecular sieve pretreatment: Take 10g of X-type molecular sieve, wash with deionized water, and dry. 2 PO 4 500 mL of the solution was soaked at room temperature for 30 min, filtered, and washed with deionized water for more than 3 times until the pH of the washing solution was neutral; then 500 mL of 0.02 wt % NaOH solution was used to soak the molecular sieve at room temperature for 20 min, filtered, and washed with deionized water for more than 3 times until the pH of the washing solution was neutral; finally, it was dried in a muffle furnace at 480° C. for 8 h.

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

[0049] Loading: fully mix the pretreated molecular sieve and the loading liquid, and shake until the loading liquid is fully absorbed; then place in a desiccator for 24 hours for aging.

[0050] Reduction: The aged catalyst precursor was placed in a tube furnace and heated with 5% H 2 (Ar gas was used as inert gas) and fully reduced at 90°C for 1 hour. After reduction, the mixture was washed with deionized water for more than 3 times until the Cl content of the washing solution was less than 500 ppm, and then dried and stored.

[0051] Example 2

[0052] The preparation method of the catalyst is as follows:

[0053] Molecular sieve pretreatment: Take 10g of X-type molecular sieve, wash with deionized water, and dry. 2 PO 4 500 mL of the solution was soaked at room temperature for 40 min, filtered, and washed with deionized water for more than 3 times until the pH of the washing solution was neutral; then 500 mL of a 0.03 wt % NaOH solution was used to soak the molecular sieve at room temperature for 30 min, filtered, and washed with deionized water for more than 3 times until the pH of the washing solution was neutral; finally, it was dried in a muffle furnace at 480° C. for 8 h.

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

[0055] Loading: fully mix the pretreated molecular sieve and the loading liquid, and shake until the loading liquid is fully absorbed; then place in a desiccator for 24 hours for aging.

[0056] Reduction: The aged catalyst precursor was placed in a tube furnace and heated with 5% H 2 (Ar gas was used as inert gas) and fully reduced at 70°C for 2h. After reduction, the mixture was washed with deionized water for more than 3 times until the Cl content of the washing solution was less than 500ppm, and then dried and stored.

[0057] Example 3

[0058] The preparation method of the catalyst is as follows:

[0059] Molecular sieve pretreatment: Take 10g of X-type molecular sieve, wash with deionized water, and dry. 2 PO 4 500 mL of the solution was soaked at room temperature for 50 min, filtered, and washed with deionized water for more than 3 times until the pH of the washing solution was neutral; then 500 mL of a 0.05 wt% NaOH solution was used to soak the molecular sieve at room temperature for 20 min, filtered, and washed with deionized water for more than 3 times until the pH of the washing solution was neutral; finally, it was dried in a muffle furnace at 480°C for 8 h.

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

[0061] Loading: fully mix the pretreated molecular sieve and the loading liquid, and shake until the loading liquid is fully absorbed; then place in a desiccator for 24 hours for aging.

[0062] Reduction: The aged catalyst precursor was placed in a tube furnace and heated with 5% H 2 (Ar gas was used as inert gas) and fully reduced at 90°C for 1 hour. After reduction, the mixture was washed with deionized water for more than 3 times until the Cl content of the washing solution was less than 500 ppm, and then dried and stored.

[0063] Example 4

[0064] The preparation method of the catalyst is similar to that of Example 1, except for the molecular sieve pretreatment step.

[0065] Molecular sieve pretreatment: Take 10g of X-type molecular sieve, wash with deionized water, and dry. Use 0.5wt% NaH 2 PO 4 500 mL of the solution was soaked at room temperature for 30 min, filtered, and washed with deionized water for more than 3 times until the pH of the washing solution was neutral; then dried in a muffle furnace at 480°C for 8 h.

[0066] Example 5

[0067] The preparation method of the catalyst is similar to that of Example 1, except for the molecular sieve pretreatment step.

[0068] Molecular sieve pretreatment: Take 10g of X-type 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, and wash with deionized water for 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 preparation method of the catalyst is similar to that of 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 for more than 3 times until the pH of the washing liquid is neutral, and then dry it in a muffle furnace at 480°C for 8 hours.

[0072] Example 7

[0073] The preparation method of the catalyst is the same as that of Example 6, except that 0.2 g of sodium dodecyl sulfate and 0.2 g of octadecyl dihydroxyethyl amine oxide in the loading liquid are replaced with 0.4 g of sodium dodecyl sulfate.

[0074] Example 8

[0075] The preparation method of the catalyst is the same as that of Example 6, except that 0.2 g of sodium dodecyl sulfate and 0.2 g of octadecyl dihydroxyethyl amine oxide in the loading liquid are replaced with 0.4 g of octadecyl dihydroxyethyl amine oxide.

[0076] Example 9

[0077] The preparation method of the catalyst is similar to that of Example 6, except that 0.2 g of sodium dodecyl sulfate and 0.2 g of octadecyl dihydroxyethyl amine oxide in the loading liquid are replaced with 0.2 g of sodium dodecylbenzene sulfonate and 0.2 g of octadecyl dihydroxyethyl amine oxide.

[0078] Example 10

[0079] The preparation method of the catalyst is the same as that of Example 6, except that 0.2 g of sodium dodecyl sulfate and 0.2 g of octadecyl dihydroxyethyl amine oxide in the loading liquid are replaced with 0.2 g of sodium decyl sulfate and 0.2 g of octadecyl dihydroxyethyl amine oxide.

[0080] Embodiment 11

[0081] The preparation method of the catalyst is the same as that of Example 6, except that 0.2 g of sodium dodecyl sulfate and 0.2 g of octadecyl dihydroxyethyl amine oxide in the loading liquid are replaced with 0.2 g of sodium tridecyl hydrogen sulfate and 0.2 g of octadecyl dihydroxyethyl amine oxide.

[0082] Example 12

[0083] The preparation method of the catalyst is the same as that of Example 6, except that 0.2 g of sodium dodecyl sulfate and 0.2 g of octadecyl dihydroxyethyl amine oxide in the loading liquid are replaced with 0.2 g of sodium dodecyl sulfate and 0.2 g of hexadecyl dimethyl amine oxide.

[0084] Example 13

[0085] The preparation method of the catalyst refers to Example 4, with the only difference being that after aging, the aged catalyst precursor is treated with 500 mL of 0.02 wt% NaOH solution at room temperature for 10 min on the molecular sieve, filtered, and washed with deionized water for more than 3 times until the pH of the washing solution is neutral, and then the catalyst precursor is dried and then subjected to the reduction step.

[0086] Embodiment 14

[0087] The preparation method of the catalyst is similar to that of Example 5, except that after aging, the aged catalyst precursor is treated with 0.5 wt% NaH 2 PO 4500 mL of the solution was treated at room temperature for 10 min, filtered, and washed with deionized water for more than 3 times until the pH of the washing solution was neutral, and then the catalyst precursor was dried and then subjected to the reduction step.

[0088] Embodiment 15

[0089] The preparation method of the catalyst is similar to that of Example 1, except that the X-type molecular sieve is replaced by the Y-type molecular sieve.

[0090] Comparative Example 1

[0091] The preparation method of the catalyst is as follows:

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

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

[0094] Loading: fully mix the pretreated molecular sieve and the loading liquid, and shake until the loading liquid is fully absorbed; then place in a desiccator for 24 hours for aging.

[0095] Reduction: The aged catalyst precursor was placed in a tube furnace and heated with 5% H 2 (Ar gas was used as inert gas) and fully reduced at 90°C for 1 hour. After reduction, the mixture was washed with deionized water for more than 3 times until the Cl content of the washing solution was less than 500 ppm, and then dried and stored.

[0096] Catalyst performance evaluation

[0097] The evaluation method is as follows:

[0098] Add 0.2 g of catalyst, 48 mL of deionized water, and 12 mL of 4-CBA to a 100 mL dynamic pressure reactor. Purge with nitrogen and pressurize the reactor to 10 bar. After heating to 250 ° C, start to introduce hydrogen. The reaction temperature reaches a maximum of 270 ° C and the reaction time is 2 hours. After the reaction is completed, the conversion rate of 4-CBA is obtained by chromatographic analysis.

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

[0100]

[0101]

[0102] By comparing the catalysts of Example 1, Examples 4-6, and Examples 13-14, it can be seen that the use of NaH 2 PO 4Solution treatment and / or NaOH solution pretreatment of the carrier can improve the 4-CBA conversion rate of the catalyst; and the catalytic performance of the catalyst prepared by sequentially pretreatment with the two solutions is better than that of the catalyst prepared by pretreatment with only one of the solutions.

[0103] By comparing the catalysts of Examples 6-12, it can be seen that the surfactant in the loading liquid is a combination of anionic surfactant and tertiary amine oxide surfactant. Compared with using only one of the surfactants, the catalyst can have a higher 4-CBA conversion rate.

[0104] By comparing the catalysts of Example 1 and Example 15, it can be seen that the use of X-type molecular sieve as a carrier can make the catalyst have better catalytic performance than using Y-type molecular sieve.

[0105] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation to 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 words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein, on the contrary, the present invention can be extended to all other methods and applications with the same functions.

Claims

1. A method for preparing a catalyst, characterized in that: include: The active component is loaded on the carrier using a loading liquid, and then subjected to a reduction treatment to obtain the catalyst; The loading liquid includes an active component precursor and a surfactant.

2. The preparation method according to claim 1, characterized in that: The surfactant includes an anionic surfactant and / or a tertiary amine oxide surfactant; Preferably, 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 an alkali metal alkyl sulfate and an alkylbenzene sulfonate; And / or, the structural formula of the tertiary amine oxide surfactant is R1N(R2)2O, wherein R1 is selected from C 10 ~C 20 Alkyl, R2 is selected from C1~C5 alkyl, hydroxyl-substituted C1~C5 alkyl; preferably, 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.

3. The preparation method according to claim 2, characterized in that: The alkyl carbon number of the alkali metal alkyl sulfate is 10 to 20; preferably, the alkali metal alkyl sulfate includes at least one of decyl sodium sulfate, undecyl sodium sulfate, dodecyl sodium sulfate, dodecyl sodium hydrogen sulfate, tridecyl sodium hydrogen sulfate, and octadecyl sodium sulfate; And / or, the alkylbenzene sulfonate includes at least one of sodium dodecylbenzene sulfonate, potassium dodecylbenzene sulfonate, calcium dodecylbenzene sulfonate, magnesium dodecylbenzene sulfonate, tetrabutylammonium trifluoromethanesulfonate, and hexadecyltrimethylammonium p-toluenesulfonate.

4. The preparation method according to any one of claims 1 to 3, characterized in that: The active component includes Pd; and / or, the active component precursor comprises a Pd-containing compound; And / or, the carrier is a FAU configuration molecular sieve; preferably, the carrier is an X-type molecular sieve; more preferably, the SiO2 / Al2O3 of the carrier is 2.2 to 3.0, preferably 2.4 to 2.

8.

5. The preparation method according to claim 4, characterized in that: The loading amount of the active component Pd in ​​the catalyst is 0.05 to 5 wt %.

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

1.

7. The preparation method according to any one of claims 1 to 6, characterized in that: The carrier is pretreated, and the pretreatment includes: treating with a NaH2PO4 solution and / or treating with a NaOH solution; Preferably, and / or, the concentration of the NaH2PO4 solution is 0.2-2wt%; and / or, the treatment time with NaH2PO4 solution is 30 to 50 minutes; and / or, the concentration of the NaOH solution is 0.01 to 0.05 wt %; And / or, the treatment time with NaOH solution is 20 to 30 minutes.

8. The preparation method according to any one of claims 1 to 7, characterized in that: The temperature of the reduction treatment is 40-100° C., the reducing gas is H 2 , and the reduction time is 1-2 hours.

9. A catalyst prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the catalyst according to claim 9 in CTA hydrofining reaction.

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