A solid supported alkali-free deodorization catalyst and a preparation method thereof

Abstract

This invention discloses a supported alkali-free desulfurization catalyst and its preparation method. The catalyst comprises, by weight, 30%-75% molecular sieve, 10-55% xMO▪yM'₂O₃, and 5%-25% cobalt phthalocyanine, wherein M represents elements of Group IIA and Group IIB, M' represents elements of Group IIIA and Group VIII, and x:y = 0.5~30. The supported alkali-free deodorization catalyst of this invention uses microporous or mesoporous molecular sieves with suitable pore structures as the basic support, and MO and M'₂O₃ as solid bases. Simultaneously, the active component, cobalt phthalocyanine, is synthesized and immobilized in the catalyst through in-situ. The catalyst of this invention exhibits a strong bond between the active component, cobalt phthalocyanine, and the molecular sieve support, resulting in minimal loss of the active component.

Description

Technical Field

[0001] This invention relates to a catalyst suitable for alkali-free deodorization of light hydrocarbons or gasoline fractions and its preparation method, specifically to a supported catalyst for alkali-free deodorization processes and its preparation method. Background Technology

[0002] Light hydrocarbons produced in oil fields or refineries contain large amounts of thiols, such as CH3SH and C2H5SH. With increasingly stringent environmental legislation and the deep utilization of light hydrocarbons, it is necessary to thoroughly remove these sulfur-containing components. Liquefied petroleum gas (LPG) desulfurization technology was first proposed by UOP in 1958 and has since developed into a mature extraction and oxidation regeneration process. Currently, the most widely used technologies are UOP's Merox desulfurization technology and Merichem Co.'s fiber-film contactor alkali treatment technology. The technical principle is that a strong alkali reacts with a thiol to produce sodium thiolate, which is then oxidized under the action of a phthalocyanine catalyst to produce disulfide substances, which are finally separated. The disadvantages of this method are: the phthalocyanine cobalt catalyst is in the alkaline phase, making it prone to aggregation and deactivation, leading to frequent catalyst replacements and high catalyst costs; moreover, the process requires continuous discharge of waste alkaline solution to meet process requirements, increasing operating costs and exacerbating environmental pressures.

[0003] To address these issues, UOP proposed a fixed-bed mercaptan removal process. The core of this process involves dispersing a phthalocyanine catalyst on a porous support and packing it into a fixed bed. Mercaptan-containing hydrocarbons flow through the fixed bed and undergo an oxidation reaction, removing the mercaptan. US Patent 2988500 discloses a supported cobalt phthalocyanine catalyst, which supports cobalt phthalocyanine on activated carbon and catalyzes the oxidation of mercaptan under the action of a soluble base. US Patent 5286372 supports a metal complex on a solid base, eliminating the need for external alkali solution when using this catalyst. Chinese Patent CN1200958A discloses a catalyst with a complex supported on the surface of a solid basic oxide. This complex is formed by combining a cobalt phthalocyanine sulfonate or cobalt phthalocyanine carboxylate with an anionic group with a cobalt quaternary ammonium salt with a positive anionic group. This catalyst does not require external alkali solution during the oxidation reaction and exhibits improved activity and stability. Chinese patent CN 104588097A discloses a method for preparing a supported phthalocyanine catalyst. The method involves spraying a solution of metal phthalocyanine, dispersant, alkaline substance and water onto a porous support, thereby achieving high dispersion and loading of the active component through the dissolution of the metal phthalocyanine.

[0004] Currently, the preparation of this type of catalyst mostly employs the supported method (the preparation methods listed in the patents above). Although catalysts prepared by the supported method have high activity, since the support and the metal phthalocyanine compound are only connected by physical adsorption, the active component is very easy to detach during the reaction and flow out of the reaction bed with the process stream, leading to catalyst deactivation. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a supported alkali-free deodorization catalyst and its preparation method. This catalyst can remove thiols from light hydrocarbons under alkali-free conditions, and the active component is bonded to the support, making it less prone to detachment and deactivation during the reaction. This significantly improves catalyst stability and reduces operating costs.

[0006] According to a first aspect of the present invention, the present invention provides a supported alkali-free deodorization catalyst.

[0007] The supported alkali-free deodorization catalyst of the present invention comprises, by weight, 35%-65% molecular sieve, 10%-55% xMO·yM'2O3, and 5%-25% cobalt phthalocyanine; wherein M is a group IIA or group IIB element, M' is a group IIIA or group VIII element, and x:y = 0.5-30.

[0008] Furthermore, M is at least one divalent metal selected from Mg, Ca, Ba, and Zn, and M' is at least one trivalent metal selected from Al, Fe, Co, and Ni.

[0009] Furthermore, the conventional molecular sieve is selected from at least one of Y-type molecular sieves, X-type molecular sieves, MCM-41 molecular sieves, Al / MCM-48 molecular sieves, and SBA-15 molecular sieves. The silica-alumina molar ratio of the molecular sieve is generally 0.5 to 200, preferably 1 to 50.

[0010] Furthermore, the supported alkali-free deodorization catalyst of the present invention comprises, by weight, 30%-75% molecular sieve, preferably 40%-55%; 10%-55% xMO·yM'2O3, preferably 20%-35%; and 5%-25% cobalt phthalocyanine, preferably 10%-20%.

[0011] According to a second aspect of the present invention, the present invention also provides a method for preparing the above-mentioned supported alkali-free deodorization catalyst.

[0012] A method for preparing a supported alkali-free deodorization catalyst includes the following:

[0013] (1) Prepare a mixture containing M 2+ and M' 3+The molecular sieve is added to the above mixed solution and stirred until homogeneous;

[0014] (2) React the molecular sieve suspension obtained in step (1) with a mixed solution of NaOH and Na2CO3 or a weak alkaline solution under stirring for a period of time;

[0015] (3) The material obtained in step (2) is filtered, washed, dried and calcined to obtain a composite carrier;

[0016] (4) Prepare a cobalt-containing solution and remove Co through ion exchange. 2+ The components are transferred to the composite carrier obtained in step (3);

[0017] (5) The material obtained in step (4) is filtered and dried to obtain Co molecular sieve solid alkali;

[0018] (6) The Co molecular sieve solid base obtained in step (5) is added to a mixture of pyridine and nitrobenzene and heated to 50-110°C with stirring; then phthalonitrile is added and the reaction is carried out at 150-300°C.

[0019] (7) The material obtained in step (6) is filtered, washed and dried to obtain the supported alkali-free deodorizing catalyst.

[0020] Furthermore, the stirring time in step (1) is generally 10 min to 180 min, preferably 60 min to 120 min.

[0021] Further, in the mixed solution of step (1), M is a Group IIA or Group IIB element, and M' is a Group IIIA or Group VIII element; preferably, M is at least one divalent metal selected from Mg, Ca, Ba, and Zn, and M' is at least one trivalent metal selected from Al, Fe, Co, and Ni. Containing M 2+ and M' 3+ The mixed solution can be a nitrate solution or a hydrochloride solution of M and M'. Containing M 2+ and M' 3+ The concentrations of the mixed solutions are typically 0.1 mol / L (saturation concentration) and 0.02 mol / L (saturation concentration). Wherein, M... 2+ and M' 3+ The molar ratio is generally 0.5 to 30.

[0022] Furthermore, in step (2), the molar ratio of NaOH to Na2CO3 in the mixed solution is 1:3 to 30:1. The weak alkaline solution is selected from at least one of ammonia water (dilute ammonia water) and dimethylamine. In step (2), when the pH value reaches 9 to 10, stirring is stopped, and the solution is allowed to stand for 10 to 180 minutes, preferably 60 to 120 minutes.

[0023] Furthermore, the filtration, washing, drying, and calcination described in step (3) can be performed under conventional operating conditions in the art. The calcination conditions are as follows: the temperature is generally 400–900℃, preferably 500–800℃, and the calcination time is 4–10 h, preferably 6–8 h. The heating rate is 3–20℃ / min, preferably 5–10℃ / min.

[0024] Furthermore, the cobalt salt solution in step (4) is selected from at least one of Co(NO3)2, Co(AC)2, or CoCl2 solution. The operating conditions for the ion exchange in step (4) are: temperature from room temperature to 200°C, preferably 80 to 150°C, and exchange time from 12 to 36 hours, preferably 18 to 26 hours.

[0025] Furthermore, the filtration, washing, drying and calcination described in step (5) can be performed under conventional operating conditions in the art, and will not be described in detail here.

[0026] Further, in the mixture described in step (6), the concentration of pyridine is 0.1-0.5 mol / L. The heating temperature is 50-110℃, preferably 80-110℃; after adding phthalonitrile, the reaction temperature is adjusted to 110-300℃, preferably 150-220℃, and the reaction continues for 0.5-3h, preferably 1-2h, after adding phthalonitrile.

[0027] Furthermore, the filtration, washing, and drying described in step (7) are performed using conventional practices in the art.

[0028] The supported alkali-free deodorization catalyst provided by this invention can catalytically oxidize thiols to disulfides under alkaline conditions. Compared with conventional processes, it consumes no alkali solution, fundamentally solving the environmental problem of waste alkali discharge. Furthermore, this catalyst uses a supported method to combine cobalt phthalocyanine with mesoporous molecular sieves, effectively reducing the problem of cobalt phthalocyanine catalyst aggregation and deactivation.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The supported alkali-free deodorization catalyst provided by this invention uses microporous or mesoporous molecular sieves with suitable pore structures as the basic support, and MO and M'2O3 as solid bases. Simultaneously, the active component, cobalt phthalocyanine, is synthesized in situ and immobilized into the catalyst. The active component and the cobalt phthalocyanine are firmly bonded to the molecular sieve support, exhibiting the characteristic of minimal loss of the active component.

[0031] 2. In the catalyst preparation method provided by the present invention, the mesoporous molecular sieve is first impregnated with a mixed solution containing M(NO3)2 and M'(NO3)3, and then calcined to obtain a solid alkali, thereby creating an alkaline environment on the molecular sieve support and reducing or even eliminating the consumption of alkali solution in the desulfurization process.

[0032] 3. The catalyst provided by this invention forms a Co-molecular sieve structure through ion exchange and is synthesized in situ to form cobalt phthalocyanine. Compared with similar supported catalysts, cobalt phthalocyanine is bonded to the molecular sieve through chemical bonds, and it basically does not undergo freeing, shedding, or aggregation during the catalytic reaction, thus avoiding deactivation and having a longer service life. Detailed Implementation

[0033] The following detailed description of the supported alkali-free desulfurization catalyst and its preparation method according to the present invention is provided in conjunction with specific embodiments. Unless otherwise specified, all percentages mentioned in the embodiments are mass percentages.

[0034] Example 1

[0035] 105g of Zn(NO3)2·6H2O and 20g of Al(NO3)3·9H2O were dissolved in 500mL of deionized water. 22.8g of SBA-15 molecular sieve (silicon-to-aluminum molar ratio of 30) was added and stirred to prepare a suspension. While continuously stirring, 1mol / L ammonia solution was simultaneously added dropwise to the same reactor, maintaining the pH at 10, and the reaction was carried out at room temperature for 3 hours. After filtration, the solution was washed with deionized water until the pH reached 7, dried at 95℃, and then calcined in a muffle furnace at 700℃ for 4 hours to obtain the catalyst composite support.

[0036] Prepare a 0.2 mol / L Co(AC)₂ solution by slowly adding 27 mL of the solution dropwise into a reaction vessel. Stir at room temperature for 2 h, then raise the temperature to 85 °C and maintain the temperature for 12 h. Cool the reaction vessel to room temperature. After filtration, washing with deionized water, and drying at 180 °C, obtain the Co molecular sieve solid alkali sample.

[0037] A Co molecular sieve solid base sample was added to a reaction vessel, along with a mixture of pyridine and nitrobenzene (pyridine concentration 0.3 mol / L, 33 mL of mixed solution). The mixture was stirred continuously and heated to 100 °C. Then, 7 g of phthalonitrile was added, and the mixture was heated to 175 °C and reacted for 3 h. After the reaction was complete, the mixture was allowed to cool naturally to room temperature. The catalyst was filtered, washed successively with hot nitrobenzene, dilute hydrochloric acid, deionized water, and methanol, and then dried to obtain the supported catalyst.

[0038] Example 2

[0039] 115g Ni(NO3)2·6H2O and 20g Al(NO3)3·9H2O were mixed and dissolved in 500mL deionized water. 33.5g HY molecular sieve (silicon-to-aluminum molar ratio of 2) was added and stirred to prepare a suspension. While continuously stirring, a 1mol / L mixed solution of NaOH and Na2CO3 (NaOH to Na2CO3 molar ratio 1:1) was simultaneously added dropwise to the same reactor, maintaining the pH at 10, and the reaction was carried out at room temperature for 5 hours. After filtration, the solution was washed with deionized water until the pH reached 7, dried at 80℃, and then calcined in a muffle furnace at 650℃ for 8 hours to obtain the catalyst composite support.

[0040] Prepare a 0.2 mol / L Co(AC)₂ solution, and slowly add 54 mL of the solution dropwise into a reaction vessel. Stir at room temperature for 2 h, then raise the temperature to 85 °C and maintain it for 20 h. Cool the reaction vessel to room temperature. After filtration, washing with deionized water, and drying at 190 °C, obtain the Co(Y) molecular sieve solid alkali sample.

[0041] A Co(Y) molecular sieve solid base sample was added to a reaction vessel, along with a mixture of pyridine and nitrobenzene (pyridine concentration 0.3 mol / L, 65 mL of mixed solution). The mixture was stirred continuously and heated to 90 °C. Then, 14 g of phthalonitrile was added, and the mixture was heated to 190 °C and reacted for 3 h. After the reaction was complete, the mixture was allowed to cool naturally to room temperature. The catalyst was filtered, washed successively with hot nitrobenzene, dilute hydrochloric acid, deionized water, and methanol, and then dried to obtain the supported catalyst.

[0042] Example 3

[0043] 58g of Mg(NO3)2·6H2O and 20g of Al(NO3)3·9H2O were dissolved in 300mL of deionized water. 14.3g of SBA-15 molecular sieve (silicon-to-aluminum molar ratio of 30) was added and stirred to prepare a suspension. While continuously stirring, 1mol / L ammonia solution was simultaneously added dropwise to the same reactor, maintaining the pH at 10, and the reaction was carried out at room temperature for 4 hours. After filtration, the solution was washed with deionized water until the pH reached 7, dried at 90℃, and then calcined in a muffle furnace at 700℃ for 5 hours to obtain the catalyst composite support.

[0044] Prepare a 0.2 mol / L Co(NO3)2 solution, and slowly add 27 mL of the solution dropwise into a reaction vessel. Stir at room temperature for 5 h, then raise the temperature to 120 °C and maintain it for 24 h. Cool the reaction vessel to room temperature. After filtration, washing with deionized water, and drying at 200 °C, obtain the Co(Y) molecular sieve solid alkali sample.

[0045] A Co molecular sieve solid base sample was added to a reaction vessel, along with a mixture of pyridine and nitrobenzene (pyridine concentration 0.3 mol / L, 33 mL of mixed solution). The mixture was stirred continuously and heated to 100 °C. Then, 7 g of phthalonitrile was added, and the mixture was heated to 200 °C and reacted for 2 h. After the reaction was complete, the mixture was allowed to cool naturally to room temperature. The catalyst was filtered, washed successively with hot nitrobenzene, dilute hydrochloric acid, deionized water, and methanol, and then dried to obtain the supported catalyst.

[0046] Example 4

[0047] 56g of Mg(NO3)2·6H2O and 20g of Al(NO3)3·9H2O were dissolved in 300mL of deionized water. 21.1g of HY molecular sieve (silicon-to-aluminum molar ratio of 2) was added and stirred to prepare a suspension. While continuously stirring, a 1mol / L mixed solution of NaOH and Na2CO3 (NaOH to Na2CO3 molar ratio 1:2) was simultaneously added dropwise to the same reactor, maintaining the pH at 10, and the reaction was carried out at room temperature for 4.5h. After filtration, the solution was washed with deionized water until the pH reached 7, dried at 80℃, and then calcined in a muffle furnace at 650℃ for 6h to obtain the catalyst composite support.

[0048] Prepare a 0.2 mol / L CoCl2 solution, and slowly add 55 mL of the solution dropwise into the reaction vessel. Stir at room temperature for 5 h, then raise the temperature to 120 °C and maintain it for 28 h. Cool the reaction vessel to room temperature. After filtration, washing with deionized water, and drying at 150 °C, obtain the Co(Y) molecular sieve solid alkali sample.

[0049] A Co(Y) molecular sieve solid base sample was added to a reaction vessel, along with a mixture of pyridine and nitrobenzene (pyridine concentration 0.3 mol / L, 66 mL of mixed solution). The mixture was stirred continuously and heated to 100 °C. Then, 15 g of phthalonitrile was added, and the mixture was heated to 195 °C and reacted for 1.6 h. After the reaction was complete, the mixture was allowed to cool naturally to room temperature. The catalyst was filtered, washed successively with hot nitrobenzene, dilute hydrochloric acid, deionized water, and methanol, and then dried to obtain the supported catalyst.

[0050] Example 5

[0051] 30g of Mg(NO3)2·6H2O and 8g of Al(NO3)3·9H2O were dissolved in 200mL of deionized water. 17.1g of HY molecular sieve (silicon-to-aluminum molar ratio of 2) was added and stirred to prepare a suspension. While continuously stirring, 0.5mol / L ammonia solution was simultaneously added dropwise to the same reactor, maintaining the pH at 9, and the reaction was carried out at room temperature for 3 hours. After filtration, the solution was washed with deionized water until the pH reached 7, dried at 100℃, and then calcined in a muffle furnace at 500℃ for 8 hours to obtain the catalyst composite support.

[0052] Prepare a 0.2 mol / L Co(AC)₂ solution, and slowly add 55 mL of the solution dropwise into a reaction vessel. Stir at room temperature for 2 h, then raise the temperature to 150 °C and maintain it for 18 h. Cool the reaction vessel to room temperature. After filtration, washing with deionized water, and drying at 150 °C, obtain the Co(Y) molecular sieve solid alkali sample.

[0053] A Co(Y) molecular sieve solid base sample was added to a reaction vessel, along with a mixture of pyridine and nitrobenzene (pyridine concentration 0.3 mol / L, 67 mL mixed solution). The mixture was stirred continuously and heated to 90 °C. Then, 15 g of phthalonitrile was added, and the mixture was heated to 180 °C and reacted for 3 h. After the reaction was complete, the mixture was allowed to cool naturally to room temperature. The catalyst was filtered, washed successively with hot nitrobenzene, dilute hydrochloric acid, deionized water, and methanol, and then dried to obtain the supported catalyst.

[0054] Example 6

[0055] 5g of Cr(NO3)3·9H2O and 8g of Mg(NO3)2·9H2O were dissolved in 200mL of deionized water. 14.8g of HY molecular sieve (silicon-to-aluminum molar ratio of 2) was added and stirred to prepare a suspension. While continuously stirring, 0.8mol / L ammonia solution was simultaneously added dropwise to the same reactor, maintaining the pH at 11, and the reaction was carried out at room temperature for 4 hours. After filtration, the solution was washed with deionized water until the pH reached 7, dried at 90℃, and then calcined in a muffle furnace at 800℃ for 5 hours to obtain the catalyst composite support.

[0056] Prepare a 0.2 mol / L Co(AC)₂ solution, and slowly add 55 mL of the solution dropwise into a reaction vessel. Stir at room temperature for 2 h, then raise the temperature to 110 °C and maintain it for 22 h. Cool the reaction vessel to room temperature. After filtration, washing with deionized water, and drying at 190 °C, obtain the Co(Y) molecular sieve solid alkali sample.

[0057] A Co(Y) molecular sieve solid base sample was added to a reaction vessel, along with a mixture of pyridine and nitrobenzene (pyridine concentration 0.3 mol / L, 66 mL of mixed solution). The mixture was stirred continuously and heated to 90 °C. Then, 14 g of phthalonitrile was added, and the mixture was heated to 110 °C and reacted for 3 h. After the reaction was complete, the mixture was allowed to cool naturally to room temperature. The catalyst was filtered, washed successively with hot nitrobenzene, dilute hydrochloric acid, deionized water, and methanol, and then dried to obtain the supported catalyst.

[0058] Comparative Example 1

[0059] An alkali-free desulfurization catalyst was prepared using the method disclosed in CN1200958A. The catalyst composition was: 60 wt% molecular sieve, 20% solid alkali, and 20% cobalt phthalocyanine. The molecular sieve and solid alkali were the same as in Example 5.

[0060] Comparative Example 2

[0061] An alkali-free desulfurization catalyst was prepared using the method disclosed in CN1978058A. The catalyst composition was 65% molecular sieve, 10% solid alkali, and 25% cobalt phthalocyanine. The molecular sieve and solid alkali were the same as in Example 6.

[0062] Table 1 Catalyst Composition (wt%)

[0063]

[0064] Desulfurization evaluation experiments were conducted on the catalysts prepared in Examples 1-6 and Comparative Examples 1-2. The properties of the experimental feedstock were: sulfur content 12000 μg / g, mercaptan sulfur content 11500 μg / g. A fixed-bed reactor with top feed was used; the reaction conditions were: volume hourly space velocity (VHSV) 1 h⁻¹. -1 The reaction temperature was 25℃, and the reaction pressure was 1.5MPa. The catalyst activity evaluation and stability test results are listed in Tables 2 and 3, respectively.

[0065] Table 2 Evaluation Results (Sampling Time: 10h)

[0066]

[0067]

[0068] Table 3. Stability Evaluation (Product Thiol Sulfur, μg / g)

[0069] Sampling time 48h 96h 144h 192h Example 1 ＜2 ＜2 4 8 Example 2 ＜2 ＜2 3 5 Example 3 ＜2 ＜2 2 4 Example 4 ＜2 ＜2 ＜2 2 Example 5 ＜2 ＜2 ＜2 ＜2 Example 6 ＜2 ＜2 ＜2 ＜2 Comparative Example 1 ＜2 ＜2 6 20 Comparative Example 2 ＜2 ＜2 11 50

Claims

1. A method for preparing a supported alkali-free deodorization catalyst, comprising the following: (1) Prepare a formula containing M 2+ and M' 3+ The molecular sieve is added to the above mixed solution and stirred until homogeneous; (2) Add the material from step (1) and a mixed solution containing NaOH and Na2CO3 or a weak alkaline solution dropwise into the reactor and react for a period of time with stirring; (3) The material obtained in step (2) is filtered, washed, dried and calcined to obtain a composite carrier; (4) Prepare a cobalt salt solution and remove Co through ion exchange. 2+ The components are transferred to the composite carrier obtained in step (3); (5) The material obtained in step (4) is filtered and dried to obtain Co molecular sieve solid alkali; (6) The Co molecular sieve solid base obtained in step (5) is added to a mixture of pyridine and nitrobenzene and heated to 50~110℃ with stirring; then phthalonitrile is added and the reaction is carried out at 150~300℃. (7) The material obtained in step (6) is filtered, washed and dried to obtain the solid-supported alkali-free deodorizing catalyst; in, M is an element of Group IIA or Group IIB, and M' is an element of Group IIIA or Group VIII; the silicon-to-aluminum molar ratio of the molecular sieve is 0.5 to 200.

2. The preparation method according to claim 1, characterized in that, The stirring time in step (1) is 10 min to 180 min.

3. The preparation method according to claim 1, characterized in that, M is selected from at least one divalent metal from Mg, Ca, Ba, and Zn, and M' is selected from at least one trivalent metal from Al, Fe, Co, and Ni.

4. The preparation method according to claim 1, characterized in that, The one containing M 2+ and M' 3+ The mixed solution is a nitrate solution or hydrochloride solution of M and M', wherein the solution containing M 2+ and M' 3+ The concentrations of the mixed solutions are 0.1 mol / L - saturation concentration and 0.02 mol / L - saturation concentration, respectively; where M 2+ and M' 3+ The molar ratio is 0.5~30.

5. The preparation method according to claim 1, characterized in that, The one containing M 2+ and M' 3+ The molar ratio of NaOH to Na2CO3 in the mixed solution is 1:3 to 30:1; the weak alkaline solution is selected from at least one of dilute ammonia water and dimethylamine.

6. The preparation method according to claim 1, characterized in that, In step (2), stop stirring when the pH value reaches 9-10 and let it stand for 10-180 minutes.

7. The preparation method according to claim 1, characterized in that, The calcination conditions in step (3) are: temperature of 400~900℃ and calcination time of 4-10h.

8. The preparation method according to claim 1, characterized in that, The cobalt salt solution mentioned in step (4) is selected from at least one of Co(NO3)2, Co(AC)2 or CoCl2 solution.

9. The preparation method according to claim 1, characterized in that, The operating conditions for ion exchange in step (4) are: temperature from room temperature to 200℃, and exchange time from 12 to 36 hours.

10. The preparation method according to claim 1, characterized in that, In the mixture described in step (6), the concentration of pyridine is 0.1-0.5 mol / L.

11. The preparation method according to claim 1, characterized in that, The heating temperature in step (6) is 50~110℃; after adding phthalonitrile, the reaction temperature is adjusted to 150~220℃, and the reaction continues for 0.5-3h.

12. The supported alkali-free deodorization catalyst obtained by any one of the preparation methods described in claims 1-11, characterized in that, The composition by weight includes 35%-65% molecular sieve, 10%-55% xMO▪yM'2O3, and 5%-25% cobalt phthalocyanine; wherein M is a group IIA or group IIB element, M' is a group IIIA or group VIII element, and x:y = 0.5~30.

13. The supported alkali-free deodorization catalyst according to claim 12, characterized in that, M is selected from at least one divalent metal from Mg, Ca, Ba, and Zn, and M' is selected from at least one trivalent metal from Al, Fe, Co, and Ni.

14. The supported alkali-free deodorization catalyst according to claim 12, characterized in that, The molecular sieve is selected from at least one of Y-type molecular sieve, X-type molecular sieve, MCM-41 molecular sieve, Al / MCM-48 molecular sieve, and SBA-15 molecular sieve.

15. The supported alkali-free deodorization catalyst according to claim 12, characterized in that, The catalyst comprises, by weight, 40%–55% molecular sieve, 20%–35% xMO▪yM'2O3, and 10%–20% cobalt phthalocyanine.

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