Preparation method and application of tert-dodecyl mercaptan catalyst

Abstract

The invention provides a method for improving the stability of a tert-dodecyl mercaptan catalyst and application of the tert-dodecyl mercaptan catalyst. The method comprises the following steps: step 1, dissolving a metal precursor and a functional additive in water or ethanol according to a certain molar ratio; 2, calculating the water absorption rate of the Y-type molecular sieve, placing the dried Y-type molecular sieve in the solution, and carrying out equivalent-volume impregnation, and 3, carrying out low-temperature drying on the impregnated Y-type molecular sieve obtained in the step 2, and then carrying out high-temperature roasting to obtain the modified Y-type molecular sieve. The catalyst prepared by the method provided by the invention is suitable for synthesis of tert-dodecyl mercaptan by addition of isododecene and hydrogen sulfide, has low requirements on olefin content of raw materials, and the obtained product has high yield and good stability and is suitable for industrial production.

Description

Technical Field

[0001] The present invention relates to a method for improving the stability of a catalyst for tert-dodecyl mercaptan and its application, belonging to the field of organic chemical industry. Background Art

[0002] As one of the important products in the mercaptan series, tert-dodecyl mercaptan (TDM) is widely used in fields such as the synthesis of industrial materials, medicine, surfactants, and organic chemical intermediates. Especially as a polymer molecular weight regulator and chain transfer agent, its application in the polymer synthesis industry is irreplaceable. In recent years, China has developed rapidly in the field of polymer material synthesis. The apparent consumption of rubber and resin in the country has shown an increasing trend year by year. In the future, the demand for TDM in China will further increase, and even show a doubling growth situation.

[0003] The synthesis of TDM mainly depends on the selection of raw material carbon sources and catalyst types. The one-step addition of isododecene and hydrogen sulfide to produce TDM has a simple process and mature technology. It is the main process route that has been studied most widely and has been industrialized. Generally, butene trimer or propylene tetramer is selected as the dodecene raw material, and aluminum trichloride, resin, Y-type molecular sieve, etc. are selected as catalysts. However, currently commercial catalysts generally have problems such as low conversion rate, high requirements for raw material content, serious pollution, and short service life, which severely restrict their industrial applications. Although patents CN116162048A and CN115850132A have good catalytic activity by modifying Y-type molecular sieve with organic acids or organic ammonium, they still face the problem of catalyst deactivation due to carbon deposition or sulfur deposition. Therefore, it is of great significance to invent a highly stable catalyst for the synthesis of tert-dodecyl mercaptan. Summary of the Invention

[0004] The present invention provides a method for improving the stability of a catalyst for tert-dodecyl mercaptan and its application. Loading a certain amount of metal on the molecular sieve using a functional additive is beneficial to improving the stability of the catalyst, reducing carbon deposition and sulfur deposition, extending the service life, and enabling the addition of isododecene and hydrogen sulfide to produce tert-dodecyl mercaptan in a reaction kettle and a fixed bed.

[0005] Technical Solution 1: Preparation of the Catalyst This method includes the following steps: Step 1, dissolving a metal precursor and a functional additive in water or ethanol according to a certain molar ratio; Step 2, calculating the water absorption rate of the Y-type molecular sieve, and placing the dried Y-type molecular sieve in the above solution for equal-volume impregnation; Step 3, drying the impregnated Y-type molecular sieve obtained in Step 2 at a low temperature, and then calcining it at a high temperature in an N2 atmosphere to obtain a modified Y-type molecular sieve.

[0006] The metal precursors described in Step 1 can be one or more of nitrates, sulfates, chlorides of metals such as cobalt, molybdenum, nickel, copper, potassium, and their respective hydrates; The functional promoter described in Step 1 is a mixture of triethylenetetraminehexaacetic acid or ethylenediaminetetraacetic dianhydride and 4-aminopyrazole or 2-amino-1,3,4-thiadiazole.

[0007] Specifically, it is a mixture of triethylenetetraminehexaacetic acid and 4-aminopyrazole; or a mixture of triethylenetetraminehexaacetic acid and 2-amino-1,3,4-thiadiazole; or a mixture of ethylenediaminetetraacetic dianhydride and 4-aminopyrazole; or a mixture of ethylenediaminetetraacetic dianhydride and 2-amino-1,3,4-thiadiazole.

[0008] The molar ratio of triethylenetetraminehexaacetic acid or ethylenediaminetetraacetic dianhydride to 4-aminopyrazole or 2-amino-1,3,4-thiadiazole is 1:0.5 - 2.

[0009] The molar ratio of the metal ions to the functional promoter described in Step 1 is 1:1 - 1:5.

[0010] The Y-type molecular sieve described in Step 2 can be one of NaY, HY, REY, USY, mesoporous Y, and it is impregnated with an equal volume of the metal salt solution for 1 - 6 h.

[0011] The impregnated Y-type molecular sieve in Step 3 is dried at a low temperature in an oven at a temperature of 60 - 100 °C for 6 - 12 h, and then calcined at a high temperature in an N2 atmosphere at a temperature of 200 - 300 °C for 2 - 8 h.

[0012] Technical solution two: Application of the catalyst The modified Y molecular sieve described can be applied to the addition synthesis of tert-dodecyl mercaptan from butene trimer or propene tetramer and hydrogen sulfide, and there is no requirement for the olefin content of butene trimer and propene tetramer; The modified Y molecular sieve described can be applied to a high-pressure reactor and a fixed-bed reactor, and the reaction conditions are: temperature 50 - 120 °C; pressure 0 - 5.0 MPa; volume space velocity 0.1 - 1.0 h -1 ; the molar ratio of hydrogen sulfide to isododecene is 5 - 20:1.

[0013] The beneficial effects of the present invention are as follows: (1) The modified Y molecular sieve catalyst prepared by the method of the present invention has better anti-coking and anti-sulfur accumulation characteristics due to metal regulation, and has more and more stable active sites compared with the unmodified molecular sieve catalyst.

[0014] (2) Due to the action of the functional additive, the metal-modified Y zeolite catalyst prepared by the method of the present invention participates in the coordination of metal ions, enhances the chelation effect between the zeolite and the metal, makes the metal dispersion more uniform, and combines more stably.

[0015] (3) The modified Y zeolite catalyst prepared by the method of the present invention has a simple synthesis method, high yield, long life, reduces production costs, and reduces the generation of three wastes.

[0016] (4) The modified Y zeolite catalyst prepared by the method of the present invention is suitable for the addition of isododecene with different sources and different olefin contents to hydrogen sulfide to form tert-dodecyl mercaptan. It has a high conversion rate and a high mercaptan yield, and is suitable for large-scale production.

[0017] (5) Compared with the modified resin catalyst (the mercaptan yield drops from 70 - 80% to 40 - 50% after 1000 h), the mercaptan yield of the modified Y zeolite catalyst prepared by the method of the present invention is still above 80% after 1500 h. Specific Embodiments

[0018] To better understand the present invention, the following examples will further illustrate the technical solutions of the present invention. However, the present invention is not limited to the listed examples, and also includes any other well-known changes within the scope of the claims of the present invention.

[0019] A method for improving the stability of the tert-dodecyl mercaptan catalyst and its application, using Y zeolite impregnated with metal as the catalyst, taking isododecene as the raw material, and generating tert-dodecyl mercaptan under certain conditions in a reaction kettle or a fixed-bed reactor.

[0020] The isododecene used in the present invention is a trimer of butene and a tetramer of propylene, both of which are commercially available and have different olefin contents; hydrogen sulfide is a cylinder gas with a purity ≥ 99.5%; metal salts and other reagents are all purchased from Aladdin Reagent Company.

[0021] In the present invention, the conversion rate of isododecene and the selectivity of tert-dodecyl mercaptan are both measured by Agilent 8860 GC.

[0022] Example 1 Preparation of the catalyst: Weigh 0.01 mol of nickel nitrate, 0.03 mol of triethylenetetramine hexaacetic acid, and 0.02 mol of 4-aminopyrazole, dissolve them in 50 mL of absolute ethanol, stir evenly, then add 20 g of HY zeolite for equal-volume impregnation. After impregnating at room temperature for 3 h, dry at 100 °C for 8 h, and finally calcine the modified zeolite at 300 °C for 3 h to obtain Ni-HY zeolite.

[0023] Evaluation of the catalyst: 20 mL of Ni-HY molecular sieve was placed in a fixed-bed reactor. First, hydrogen sulfide was introduced and sulfided at 300 °C for 60 min. Then, hydrogen sulfide gas at 0.0018 mol / min and butene trimer (olefin content ≥ 70%) at 0.0003 mol / min were introduced simultaneously. The molar ratio of hydrogen sulfide to butene trimer was 6, and the space velocity was 0.2 h -1 , the reaction temperature was 50 °C, the pressure was 1.5 Mpa, the initial conversion rate was 92.8%, the selectivity was 98.9%. After continuous operation for 1000 h, the conversion rate was 88.5%, and the selectivity was 99%.

[0024] Example 2 Preparation of the catalyst: 0.01 mol of nickel nitrate, 0.03 mol of ethylenediaminetetraacetic dianhydride, and 0.02 mol of 4-aminopyrazole were dissolved in 50 mL of deionized water. After stirring evenly, 20 g of REY molecular sieve was added for equal-volume impregnation. After impregnation at room temperature for 6 h, it was dried at 80 °C for 12 h. Finally, the modified molecular sieve was calcined at 250 °C for 3 h to obtain Ni-REY molecular sieve.

[0025] Evaluation of the catalyst: 20 mL of Ni-REY molecular sieve was placed in a fixed-bed reactor. First, hydrogen sulfide was introduced and sulfided at 300 °C for 60 min. Then, hydrogen sulfide gas at 0.0036 mol / min and butene trimer (olefin content ≥ 70%) at 0.0006 mol / min were introduced simultaneously. The molar ratio of hydrogen sulfide to butene trimer was 6, and the space velocity was 0.4 h -1 , the reaction temperature was 60 °C, the pressure was 1.5 Mpa, the initial conversion rate was 94.5%, the selectivity was 98.8%. After continuous operation for 1200 h, the conversion rate was 85.6%, and the selectivity was 98.2%.

[0026] Example 3 Preparation of the catalyst: 0.01 mol of cobalt nitrate, 0.03 mol of ethylenediaminetetraacetic dianhydride, and 0.02 mol of 2-amino-1,3,4-thiadiazole were dissolved in 50 mL of deionized water. After stirring evenly, 20 g of HY molecular sieve was added for equal-volume impregnation. After impregnation at room temperature for 5 h, it was dried at 60 °C for 8 h. Finally, the modified molecular sieve was calcined at 200 °C for 6 h to obtain Co-HY molecular sieve.

[0027] Evaluation of the catalyst: 20 mL of Co-HY molecular sieve was placed in a fixed-bed reactor. First, hydrogen sulfide was introduced and sulfided at 300 °C for 60 min. Then, hydrogen sulfide gas at 0.0036 mol / min and propylene tetramer (olefin content ≥ 95%) at 0.0006 mol / min were introduced simultaneously. The molar ratio of hydrogen sulfide to propylene tetramer was 6, and the space velocity was 0.4 h -1, the reaction temperature was 60 °C, the pressure was 1.5 Mpa, the initial conversion rate was 96.2%, the selectivity was 99.6%, the continuous operation was 800 h, the conversion rate was 88.3%, and the selectivity was 98.1%.

[0028] Example 4 Preparation of catalyst: Weigh 0.02 mol of ammonium molybdate, 0.02 mol of triethylenetetraminehexaacetic acid, and 0.03 mol of 2-amino-1,3,4-thiadiazole and dissolve them in 50 mL of absolute ethanol. After stirring evenly, add 20 g of USY molecular sieve for equal-volume impregnation. After impregnating at room temperature for 3 h, dry at 80 °C for 10 h. Finally, calcine the modified molecular sieve at 250 °C for 4 h to obtain Mo-USY molecular sieve.

[0029] Evaluation of catalyst: Place 20 mL of Mo-USY molecular sieve in a fixed-bed reactor. First, introduce hydrogen sulfide and sulfide at 300 °C for 60 min. Then, simultaneously introduce 0.009 mol / min of hydrogen sulfide gas and 0.0009 mol / min of propylene tetramer (olefin content ≥ 95%). The molar ratio of hydrogen sulfide to propylene tetramer is 10, and the space velocity is 0.6 h -1 , the reaction temperature was 50 °C, the pressure was 1.5 Mpa, the initial conversion rate was 98.4%, the selectivity was 98.5%, the continuous operation was 1500 h, the conversion rate was 89.7%, and the selectivity was 97.3%.

[0030] Example 5 Preparation of catalyst: Weigh 0.01 mol of ammonium molybdate, 0.02 mol of triethylenetetraminehexaacetic acid, and 0.03 mol of 4-aminopyrazole and dissolve them in 50 mL of absolute ethanol. After stirring evenly, add 20 g of mesoporous Y molecular sieve for equal-volume impregnation. After impregnating at room temperature for 4 h, dry at 100 °C for 8 h. Finally, calcine the modified molecular sieve at 300 °C for 6 h to obtain Mo-mesoporous Y molecular sieve.

[0031] Evaluation of catalyst: Place 20 mL of Mo-mesoporous Y molecular sieve in a fixed-bed reactor. First, introduce hydrogen sulfide and sulfide at 300 °C for 60 min. Then, simultaneously introduce 0.006 mol / min of hydrogen sulfide gas and 0.0006 mol / min of propylene tetramer (olefin content ≥ 77%). The molar ratio of hydrogen sulfide to propylene tetramer is 10, and the space velocity is 0.4 h -1 , the reaction temperature was 50 °C, the pressure was 1.2 Mpa, the initial conversion rate was 88.4%, the selectivity was 96.8%, the continuous operation was 600 h, the conversion rate was 80.4%, and the selectivity was 95.3%.

[0032] Example 6 Preparation of catalyst: Weigh 0.01 mol of cobalt nitrate, 0.01 mol of ethylenediaminetetraacetic dianhydride, and 0.04 mol of 4-aminopyrazole, dissolve them in 50 mL of absolute ethanol. After stirring evenly, add 20 g of HY zeolite for isovolumetric impregnation. After impregnating at room temperature for 6 h, dry it at 100 °C for 12 h. Finally, calcine the modified zeolite at 300 °C for 3 h to obtain Co-HY zeolite.

[0033] Evaluation of catalyst: Place 20 mL of Co-HY zeolite in a fixed-bed reactor. First, introduce hydrogen sulfide and sulfide at 300 °C for 60 min. Then, simultaneously introduce 0.006 mol / min of hydrogen sulfide gas and 0.0006 mol / min of propylene tetramer (olefin content ≥ 80%). The molar ratio of hydrogen sulfide to propylene tetramer is 10, and the space velocity is 0.4 h -1 , The reaction temperature is 50 °C, the pressure is 1.0 Mpa, the initial conversion rate is 86.9%, the selectivity is 98.2%. Continuously run for 900 h, the conversion rate is 80.5%, and the selectivity is 97.1%.

[0034] Example 7 Preparation of catalyst: Weigh 0.01 mol of copper nitrate, 0.04 mol of ethylenediaminetetraacetic dianhydride, and 0.01 mol of 2-amino-1,3,4-thiadiazole, dissolve them in 50 mL of absolute ethanol. After stirring evenly, add 20 g of HY zeolite for isovolumetric impregnation. After impregnating at room temperature for 6 h, dry it at 100 °C for 12 h. Finally, calcine the modified zeolite at 300 °C for 3 h to obtain Cu-HY zeolite.

[0035] Evaluation of catalyst: Place 20 mL of Cu-HY zeolite in a fixed-bed reactor. First, introduce hydrogen sulfide and sulfide at 300 °C for 60 min. Then, simultaneously introduce 0.0048 mol / min of hydrogen sulfide gas and 0.0006 mol / min of propylene tetramer (olefin content ≥ 80%). The molar ratio of hydrogen sulfide to propylene tetramer is 8, and the space velocity is 0.4 h -1 , The reaction temperature is 50 °C, the pressure is 1.0 Mpa, the initial conversion rate is 89.3%, the selectivity is 97.2%. Continuously run for 1800 h, the conversion rate is 81.6%, and the selectivity is 95.4%.

[0036] Example 8 Preparation of catalyst: Weigh 0.01 mol of potassium nitrate, 0.04 mol of ethylenediaminetetraacetic dianhydride, and 0.01 mol of 2-amino-1,3,4-thiadiazole, dissolve them in 50 mL of absolute ethanol. After stirring evenly, add 20 g of HY molecular sieve for equal-volume impregnation. After impregnating at room temperature for 6 h, dry at 100 °C for 12 h. Finally, calcine the modified molecular sieve at 200 °C for 3 h to obtain K-HY molecular sieve.

[0037] Evaluation of catalyst: Place 20 mL of K-HY molecular sieve in a fixed-bed reactor. First, introduce hydrogen sulfide and sulfide at 300 °C for 60 min. Then, simultaneously introduce 0.0048 mol / min of hydrogen sulfide gas and 0.0006 mol / min of butene trimer (olefin content ≥ 80%). The molar ratio of hydrogen sulfide to butene trimer is 8, and the space velocity is 0.4 h -1 , the reaction temperature is 50 °C, the pressure is 1.0 Mpa, the initial conversion rate is 86.5%, the selectivity is 98.8%. Continuously run for 700 h, the conversion rate is 80.2%, and the selectivity is 97.4%.

[0038] Comparative Example 1 Preparation of catalyst: HY molecular sieve without metal impregnation.

[0039] Evaluation of catalyst: Place 20 mL of HY molecular sieve in a fixed-bed reactor. Then, simultaneously introduce 0.0048 mol / min of hydrogen sulfide gas and 0.0006 mol / min of butene trimer (olefin content ≥ 80%). The molar ratio of hydrogen sulfide to butene trimer is 6, and the space velocity is 0.4 h -1 , the reaction temperature is 50 °C, the pressure is 1.5 Mpa, the initial conversion rate is 90.9%, the selectivity is 99.2%. Continuously run for 800 h, the conversion rate is 68.2%, and the selectivity is 98.5%.

[0040] Comparative Example 2 Preparation of catalyst: REY molecular sieve without metal impregnation.

[0041] Evaluation of catalyst: Place 20 mL of REY molecular sieve in a fixed-bed reactor. Then, simultaneously introduce 0.0054 mol / min of hydrogen sulfide gas and 0.0009 mol / min of propylene tetramer (olefin content ≥ 80%). The molar ratio of hydrogen sulfide to propylene tetramer is 6, and the space velocity is 0.6 h -1 , the reaction temperature is 80 °C, the pressure is 1.0 Mpa, the initial conversion rate is 92.3%, the selectivity is 98.5%. Continuously run for 800 h, the conversion rate is 58.6%, and the selectivity is 96.4%.

[0042] Comparative Example 3 Preparation of catalyst: USY zeolite without metal impregnation.

[0043] Evaluation of catalyst: 20 mL of USY zeolite was placed in a fixed-bed reactor, and then 0.0015 mol / min of hydrogen sulfide gas and 0.00015 mol / min of butene trimer (olefin content ≥ 80%) were introduced simultaneously. The molar ratio of hydrogen sulfide to butene trimer was 10, and the space velocity was 0.1 h -1 , the reaction temperature was 70 °C, the pressure was 1.5 Mpa, the initial conversion rate was 92.9%, the selectivity was 99.6%, and it was continuously operated for 800 h. The conversion rate was 70.6%, and the selectivity was 97.2%.

[0044] Comparative Example 4 Preparation of catalyst: 0.02 mol of ammonium molybdate was weighed and dissolved in 50 mL of absolute ethanol. After stirring evenly, 20 g of USY zeolite was added for equal-volume impregnation. After impregnation at room temperature for 3 h, it was dried at 80 °C for 10 h. Finally, the modified zeolite was calcined at 250 °C for 4 h to obtain Mo-USY zeolite without adding functional additives.

[0045] Evaluation of catalyst: 20 mL of Mo-USY zeolite without adding functional additives was placed in a fixed-bed reactor. First, hydrogen sulfide was introduced and sulfided at 300 °C for 60 min, and then 0.0015 mol / min of hydrogen sulfide gas and 0.00015 mol / min of butene trimer (olefin content ≥ 90%) were introduced simultaneously. The molar ratio of hydrogen sulfide to butene trimer was 10, and the space velocity was 0.1 h -1 , the reaction temperature was 70 °C, the pressure was 1.5 Mpa, the initial conversion rate was 90.4%, the selectivity was 98.5%, and it was continuously operated for 1000 h. The conversion rate was 75.8%, and the selectivity was 97.1%.

[0046] Comparative Example 5 Preparation of catalyst: 0.02 mol of ammonium molybdate and 0.05 mol of triethylenetetramine hexaacetic acid were weighed and dissolved in 50 mL of absolute ethanol. After stirring evenly, 20 g of USY zeolite was added for equal-volume impregnation. After impregnation at room temperature for 3 h, it was dried at 80 °C for 10 h. Finally, the modified zeolite was calcined at 250 °C for 4 h to obtain Mo-USY-1 zeolite.

[0047] Evaluation of catalyst: 20 mL of Mo-USY-1 zeolite was placed in a fixed-bed reactor. First, hydrogen sulfide was introduced and sulfided at 300 °C for 60 min, and then 0.009 mol / min of hydrogen sulfide gas and 0.0009 mol / min of butene trimer (olefin content ≥ 80%) were introduced simultaneously. The molar ratio of hydrogen sulfide to butene trimer was 10, and the space velocity was 0.6 h -1, the reaction temperature was 50 °C, the pressure was 1.5 Mpa, the initial conversion rate was 92.6%, the selectivity was 99.2%, and after continuous operation for 1000 h, the conversion rate was 80.3% and the selectivity was 98.4%.

[0048] Comparative Example 6 Catalyst: the modified resin catalyst in Patent CN118080009A Evaluation of the catalyst: 20 mL of the modified resin catalyst was placed in a fixed-bed reactor, and then 0.0009 mol / min of hydrogen sulfide gas and 0.00015 mol / min of propylene tetramer (olefin content ≥ 80%) were simultaneously introduced. The molar ratio of hydrogen sulfide to propylene tetramer was 10, and the space velocity was 0.1 h -1 , the reaction temperature was 50 °C, the pressure was 1.5 Mpa, the initial conversion rate was 85.9%, the selectivity was 90.5%, and after continuous operation for 1000 h, the conversion rate was 58.2% and the selectivity was 86.3%.

Claims

1. A preparation method of a tert-dodecyl mercaptan catalyst, characterized in that, It includes the following steps: (1) Dissolve the metal precursor and the functional promoter in a solvent according to a certain molar ratio; (2) Place the dried Y-type molecular sieve in the above solution for impregnation; (3) Low-temperature dry the impregnated Y-type molecular sieve obtained in step (2), and then high-temperature calcine it in an N2 atmosphere to obtain a modified Y-type molecular sieve.

2. The preparation method of the tert-dodecyl mercaptan catalyst according to claim 1, characterized in that, The metal precursor is one or a combination of more of cobalt, molybdenum, nickel, copper, and potassium salts.

3. The preparation method of the tert-dodecyl mercaptan catalyst according to claim 1, wherein, The functional promoter is triethylenetetraminehexaacetic acid or a mixture of ethylenediaminetetraacetic anhydride and 4-aminopyrazole or 2-amino-1,3,4-thiadiazole.

4. The preparation method of the tert-dodecyl mercaptan catalyst according to claim 1, characterized in that The solvent is ethanol or distilled water.

5. The preparation method of the tert-dodecyl mercaptan catalyst according to claim 1, characterized in that, The molar ratio of the metal precursor to the functional promoter is 1:1 - 1:

5.

6. The preparation method of the tert-dodecyl mercaptan catalyst according to claim 1, wherein, The Y-type molecular sieve is any one of NaY, HY, REY, USY, and mesoporous Y.

7. The preparation method of the tert-dodecyl mercaptan catalyst according to claim 1, characterized in that, The impregnation time is 1 - 6 h, the low-temperature drying temperature is 60 - 100 °C, and the time is 6 - 12 h.

8. The preparation method of the tert-dodecyl mercaptan catalyst according to claim 1, characterized in that, The high-temperature calcination temperature is 200 - 300 °C, and the time is 2 - 8 h.

9. Application of the tert-dodecyl mercaptan catalyst prepared by the method according to any one of claims 1 - 8 in the addition of hydrogen sulfide to propylene tetramer or butene trimer to synthesize tert-dodecyl mercaptan.

10. The application according to claim 9, wherein The catalyst of tert-dodecyl mercaptan is applied to a high-pressure reactor and a fixed-bed reactor, and the reaction conditions are as follows: temperature 50 - 120 °C; pressure 0 - 5.0 MPa; space velocity 0.1 - 1.0 h -1 ; the molar ratio of hydrogen sulfide to propylene tetramer is 5 - 20:1, or the molar ratio of hydrogen sulfide to butene trimer is 5 - 20:1.