Preparation method of Ti-based material-supported Ru-based catalyst and its application

Abstract

The present invention provides a preparation method of a Ti-based material-loaded Ru-based catalyst and its application in the partial hydrogenation of benzene to produce cyclohexene. By adding additives 1 and 2 simultaneously to the Ti-based material, a higher cyclohexene yield can be obtained under conditions of lower Ru content. This is mainly due to the fact that the addition of the additives increases the alkalinity of the catalyst surface, which is more conducive to the adsorption of benzene and the desorption of cyclohexene, ultimately promoting the conversion of benzene and avoiding excessive hydrogenation of cyclohexene to produce cyclohexane. In addition, there is an electronic interaction between the additive and the metal Ru. Due to the strong electronegativity of the additive, it can adsorb electrons in the metal Ru, thereby causing it to transfer and generate Ru with a partial positive charge. δ+ 。 δ+ The presence of Ru can reduce the hydrogenation capacity of the catalyst, thereby preventing excessive hydrogenation of cyclohexene to cyclohexane. In addition, the Ru-based catalyst of the present invention has a much lower Ru content than the industrial catalyst (Ru content is 10 wt%).

Description

Technical Field

[0001] The present invention belongs to the technical field of catalyst preparation, and in particular relates to a preparation method of a Ti-based material-loaded Ru-based catalyst and application thereof. Background Art

[0002] Cyclohexene is an important industrial raw material used in the synthesis of high-value-added chemicals such as cyclohexanol, caprolactam, and adipic acid. Cyclohexene can be obtained through methods such as partial hydrogenation of benzene, dehydration of cyclohexanol, dehydrogenation of cyclohexane, and Birch reduction. Partial hydrogenation of benzene to cyclohexene is the most commonly used method due to its readily available and inexpensive raw material (benzene), simple reaction process, and ease of operation. Thermodynamically, the standard Gibbs free energy change from benzene hydrogenation to cyclohexane (-98 kJ / mol) is much smaller than that from benzene hydrogenation to cyclohexene (-23 kJ / mol), making benzene hydrogenation thermodynamically more favorable for the production of cyclohexene. Selecting the appropriate catalyst and reaction system is crucial for increasing cyclohexene yields.

[0003] Currently, academic and industrial researchers are using the following three methods to increase cyclohexene yields: 1) Adding additives. For example, Zhou et al. [Zhou G, et al. J Catal 2014;311:393-403] added additive B to Ru / ZrO2, leveraging the increased acidity and electronic interaction between B and Ru to improve cyclohexene yield. 2) Adding hydrophilic substances. For example, patent CN105664931A coats the surface of Ru particles with SiO2 to increase the hydrophilicity of the catalyst, thereby preventing the cyclohexene generated by the reaction from accumulating on the catalyst surface and over-hydrogenating to cyclohexane. Patent CN103785378A doped SiO2 into TiO2 to prepare a Ti-Si composite material, leveraging the hydrophilicity of SiO2 to improve the hydrophilicity of the catalyst surface. 3) Adding organic substances such as alcohols. For example, Estevam et al. [Estevam V, et al. Catal Commun 2003;4:91-96] added organic compounds such as methanol, ethanol, ethylene glycol, and glycerol to a Ru-based catalyst. Activity tests showed that the appropriate addition of alcohols could increase cyclohexene yields to a certain extent. Sun et al. [Sun H, et al. Chem Eng J 2013;218:415-424] added organic compounds such as ethanol, ethylene glycol, and polyethylene glycol to a Ru-Zn catalyst. Catalytic performance tests showed that the addition of polyethylene glycol could increase cyclohexene yields to a certain extent. Industrially, benzene partial hydrogenation catalysts have evolved through two stages: unsupported Ru-Zn catalysts and supported Ru-based catalysts. When China first imported Asahi Kasei's benzene partial hydrogenation process from Japan to produce cyclohexene, the catalyst used was an unsupported Ru-Zn catalyst with a Ru content of 20-30 wt%, making it very expensive. Subsequently, the Sinopec Institute of Petroleum and Chemical Industry and Zhengzhou University improved this catalyst, developing a Ru-Zn-ZrO2 catalyst with a Ru content reduced to approximately 10 wt%. While this new catalyst reduced cost, the high precious metal content still posed a significant cost burden. Therefore, developing a low-Ru catalyst with industrial applicability remains a significant challenge for both industry and academia. Summary of the Invention

[0004] The present invention aims to provide a method for preparing a catalyst for the partial hydrogenation of benzene to cyclohexene, overcoming the challenges faced by existing catalysts, such as low cyclohexene yield and high costs resulting from high precious metal content. The Ru-based catalyst provided by the present invention is primarily used for the partial hydrogenation of liquid benzene to cyclohexene. It has advantages such as low Ru content and low cost, offering a price advantage in industrial production.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] (1) Tetraethyl titanate, additives 1 and 2 were added to water, the pH value was adjusted to 8.5-9.0 with aqueous ammonia, and then heated to reflux, filtered, dried overnight, and then calcined at high temperature;

[0007] (2) Disperse the sample obtained in step 1 in water, add Ru salt, stir and dissolve, add urea or N-phenylurea, heat to reflux, filter, dry overnight, and then calcine at high temperature;

[0008] (3) The sample obtained in step 2 is dispersed in water, and hydrazine hydrate is added to reduce the metal Ru.

[0009] In some preferred embodiments, the additive 1 in step (1) is one or more of a Li salt, a Na salt, a K salt, and a Cs salt. The Li salt is one or more of LiNO3, Li2CO3, LiCl, and Li2SO4; the Na salt is one or more of NaNO3, Na2CO3, NaCl, and Na2SO4; the K salt is one or more of KNO3, K2CO3, KCl, and K2SO4; the Cs salt is one or more of CsNO3, Cs2CO3, CsCl, and Cs2SO4; and the content of the additive 1 is 1 wt% to 10 wt%.

[0010] In some preferred embodiments, the auxiliary agent 2 in step (1) is one or more of a Zn salt, a La salt, and a Co salt. The Zn salt is one or more of Zn(NO3)2·6H2O, [ZnCO3]2·[Zn(OH)2]3, ZnCl2, and ZnSO4; the La salt is one or more of La(NO3)3, La2(CO3)3·xH2O, LaCl3, and La2(SO4)3; the Co salt is one or more of Co(NO3)2·6H2O, CoCO3, CoCl2, and CoSO4·H2O; and the content of the auxiliary agent 2 is 1 wt% to 10 wt%.

[0011] In some preferred embodiments, the calcination temperature in step (1) is 350° C. to 800° C., and the calcination time is 3 h to 8 h.

[0012] In some preferred embodiments, the Ru salt in step (2) is one or more of RuCl3, Ru(acac)3 and Ru(NO)(NO3)3.

[0013] In some preferred embodiments, the content of metal Ru in step (2) is 0.5 wt% to 5.0 wt%.

[0014] In step (2), the amount of N-phenylurea added is 10-50 times the mass of the Ru salt. The amount of urea or N-phenylurea used is slightly in excess of the mass of the Ru salt.

[0015] The present invention provides a preparation method of the Ti-based material-supported Ru-based catalyst described in the above technical solution, and its application in the reaction of partially hydrogenating benzene to produce cyclohexene.

[0016] The beneficial results of the present invention are:

[0017] The present invention provides a method for preparing a Ti-based material-supported Ru-based catalyst and its application in the liquid-phase partial hydrogenation reaction to produce cyclohexene. Thanks to the synergistic effect of additives 1 and 2, the catalyst of the present invention can rapidly convert benzene into cyclohexene under conditions of low Ru content and maintain a high cyclohexene yield. This is mainly because the addition of additives 1 and 2 can change the acidity and alkalinity of the catalyst surface and interact with the metal Ru to attract some electrons to transfer from Ru to the additives, thereby generating Ru with a partial positive charge. δ+ 。 δ+ The presence of can weaken the hydrogenation ability of the Ru-based catalyst, thereby avoiding excessive hydrogenation of the product cyclohexene to cyclohexane. DETAILED DESCRIPTION

[0018] The present invention provides a method for preparing a Ti-based material-supported Ru-based catalyst for use in the partial hydrogenation of benzene to cyclohexene. The catalytic performance evaluation apparatus used in the present invention is a tank reactor, similar to the industrial production apparatus for partial hydrogenation of benzene to cyclohexene.

[0019] In this invention, unless otherwise specified, the evaluation method for the partial hydrogenation of benzene to cyclohexene is as follows: a predetermined amount of catalyst and water are loaded into a kettle reactor, which is then filled with hydrogen and evacuated three times to completely expel the air from the kettle. After pressure buildup and leak detection, the reactor is heated to the target temperature, and benzene is added, which begins the reaction timer.

[0020] In the present invention, unless otherwise specified, the reaction conditions for partial hydrogenation of benzene to cyclohexene are: 5.0 MPa, 140° C., rotation speed 1000 r / min, catalyst 1 g, benzene 50 mL, and water 100 mL.

[0021] In the present invention, unless otherwise specified, the benzene conversion and cyclohexene selectivity listed in Table 1 are all obtained under the conditions of maximum cyclohexene yield.

[0022] To further illustrate the present invention, the following embodiments are described in detail, but the protection scope of the present invention is not limited to the following embodiments.

[0023] Example 1

[0024] 14.3g of tetraethyl titanate was dispersed in 100mL of water, and 0.19g of NaNO3 (additive 1) and 0.25g of Co(NO3)2·6H2O (additive 2) were added. Ammonia was added dropwise to adjust the pH to 8.5-9.0. The mixture was refluxed at 80°C for 5 hours, filtered, dried at 100°C overnight, and then calcined at 600°C. The resulting Ti-based material doped with Na and Co, abbreviated as Na-Co-Ti, was obtained. The mass fractions of Na and Co were both 1.0wt%.

[0025] The above-mentioned Na-Co-Ti was dispersed in 150 mL of water, and 0.18 g of RuCl3 was added. After the metal salt was completely dissolved, 5 g of urea was added, and the mixture was heated under reflux at 80 ° C for 12 h. Then the mixture was filtered and washed with deionized water until there was no Cl ion in the filtrate. Finally, it was dried at 100 ° C overnight to obtain the catalyst precursor.

[0026] The catalyst precursor was dispersed in 200 mL of water, 5 g of hydrazine hydrate was added, and after stirring for 1 hour, it was filtered and washed with deionized water until the solution was neutral. The obtained product was a Ru-based catalyst supported by a Ti-based material.

[0027] Example 2

[0028] A Ti-based material-supported Ru-based catalyst was prepared with reference to Example 1. The difference from Example 1 was that the mass fractions of Na and Co in this example were both 2.5 wt %.

[0029] Example 3

[0030] A Ti-based material-supported Ru-based catalyst was prepared with reference to Example 1. The difference from Example 1 was that the mass fractions of Na and Co in this example were both 5.0 wt %.

[0031] Example 4

[0032] Referring to Example 2, a Ti-based material-supported Ru-based catalyst was prepared. The difference from Example 2 was that in this example, the Na salt was Na2CO3 and the Co salt was CoCO3.

[0033] Example 5

[0034] A Ti-based material-supported Ru-based catalyst was prepared with reference to Example 2. The difference from Example 2 is that the auxiliary agent 1 in this example is LiNO 3 .

[0035] Example 6

[0036] A Ti-based material-supported Ru-based catalyst was prepared with reference to Example 2. The difference from Example 2 is that the auxiliary agent 1 in this example is KNO3.

[0037] Example 7

[0038] Referring to Example 2, a Ti-based material-supported Ru-based catalyst was prepared. The difference from Example 2 was that the auxiliary agent 1 in this example was CsNO 3 .

[0039] Example 8

[0040] Referring to Example 2, a Ti-based material-supported Ru-based catalyst was prepared. The difference from Example 2 was that the auxiliary agent 2 in this example was Zn(NO3)2·6H2O.

[0041] Example 9

[0042] Referring to Example 2, a Ti-based material-supported Ru-based catalyst was prepared. The difference from Example 2 was that the auxiliary agent 2 in this example was La(NO3)3.

[0043] Example 10

[0044] Referring to Example 2, a Ti-based material-supported Ru-based catalyst was prepared. The difference from Example 2 was that in this example, the auxiliary agent 1 was LiNO 3 and the auxiliary agent 2 was Zn(NO 3 ) 2 ·6H 2 O.

[0045] Example 11

[0046] Referring to Example 2, a Ti-based material-supported Ru-based catalyst was prepared. The difference from Example 2 was that in this example, the auxiliary agent 1 was LiNO 3 and the auxiliary agent 2 was La(NO 3 ) 3 .

[0047] Example 12

[0048] Referring to Example 2, a Ti-based material-supported Ru-based catalyst was prepared. The difference from Example 2 was that in this example, the auxiliary agent 1 was KNO 3 and the auxiliary agent 2 was Zn(NO 3 ) 2 ·6H 2 O.

[0049] Example 13

[0050] Referring to Example 2, a Ti-based material-supported Ru-based catalyst was prepared. The difference from Example 2 was that in this example, the auxiliary agent 1 was KNO3 and the auxiliary agent 2 was La(NO3)3.

[0051] Example 14

[0052] A Ti-based material-supported Ru-based catalyst was prepared with reference to Example 2. The difference from Example 2 was that in this example, the auxiliary agent 1 was CsNO 3 and the auxiliary agent 2 was Zn(NO 3 ) 2 ·6H 2 O.

[0053] Example 15

[0054] Referring to Example 2, a Ti-based material-supported Ru-based catalyst was prepared. The difference from Example 2 was that in this example, the auxiliary agent 1 was CsNO3 and the auxiliary agent 2 was La(NO3)3.

[0055] Example 16

[0056] 14.3g of tetraethyl titanate was dispersed in 100mL of water, and 0.19g of NaNO3 (additive 1) and 0.25g of Co(NO3)2·6H2O (additive 2) were added. Ammonia was added dropwise to adjust the pH to 8.5-9.0. The mixture was refluxed at 80°C for 5 hours, filtered, dried at 100°C overnight, and then calcined at 600°C. The resulting Ti-based material doped with Na and Co, abbreviated as Na-Co-Ti, was obtained. The mass fractions of Na and Co were both 1.0wt%.

[0057] The above-mentioned Na-Co-Ti was dispersed in 150 mL of water, and 0.18 g of RuCl3 was added. After the metal salt was completely dissolved, 5 g of N-phenylurea was added. The mixture was heated under reflux at 80 °C for 12 h, filtered, and washed with deionized water until no Cl ions were left in the filtrate. Finally, it was dried at 100 °C overnight to obtain the catalyst precursor.

[0058] The catalyst precursor was dispersed in 200 mL of water, 5 g of hydrazine hydrate was added, and after stirring for 1 hour, it was filtered and washed with deionized water until the solution was neutral. The obtained product was a Ru-based catalyst supported by a Ti-based material.

[0059] Comparative Sample 1

[0060] Referring to Example 2, a Ti-based material-supported Ru-based catalyst was prepared. The difference from Example 2 is that the additives 1 and 2 were not present in this example.

[0061] Comparative Sample 2

[0062] Referring to Example 2, a Ti-based material-supported Ru-based catalyst was prepared. The difference from Example 2 is that the additive 1 was not included in this example.

[0063] Comparative Sample 3

[0064] A Ti-based material-supported Ru-based catalyst was prepared with reference to Example 2. The difference from Example 2 is that there is no auxiliary agent 2 in this example.

[0065] The above samples were evaluated for benzene partial hydrogenation activity under the above-mentioned conditions. The catalytic activity test results are listed in Table 1. From the implementation results, it can be seen that the simultaneous addition of additives 1 and 2 can significantly increase the cyclohexene yield. This is mainly because the addition of additives 1 and 2 can change the acidity and alkalinity of the catalyst surface, increase the benzene adsorption capacity and cyclohexene desorption capacity, and interact with metal Ru to attract some electrons to transfer from Ru to the additives, thereby generating some positively charged Ru. δ+ 。 δ+The presence of ruthenium can weaken the hydrogenation capacity of Ru-based catalysts, thereby preventing excessive hydrogenation of the cyclohexene product to cyclohexane. Furthermore, thanks to the promoting effect of additives 1 and 2, the catalyst of the present invention can achieve a cyclohexene yield of 50 mol% at a relatively low Ru content. The metallic Ru content is far lower than that of industrial catalysts, and no additional zinc sulfate additive is required during the reaction.

[0066] Table 1. Performance results of partial hydrogenation of benzene in Examples.

[0067]

[0068]

Claims

1. A method for preparing a Ti-based material-supported Ru-based catalyst, characterized in that: The following steps are involved: (1) Tetraethyl titanate, additives 1 and 2 are added to water, the pH value is adjusted to 8.5-9.0 with aqueous ammonia, then heated to reflux, filtered, dried overnight, and then calcined at high temperature; additive 1 is one or more of Li salt, Na salt, K salt and Cs salt; additive 2 is one or more of Zn salt, La salt and Co salt; (2) Disperse the sample obtained in step 1 in water, add Ru salt, stir and dissolve, add urea or N-phenylurea, heat to reflux, filter, dry overnight, and then calcine at high temperature; (3) The sample obtained in step 2 was dispersed in water, and hydrazine hydrate was added to reduce the metal Ru.

2. The method according to claim 1, characterized in that In step (1), the Li salt is one or more of LiNO3, Li2CO3, LiCl and Li2SO4; The Na salt is one or more of NaNO3, Na2CO3, NaCl and Na2SO4; The K salt is one or more of KNO3, K2CO3, KCl and K2SO4; The Cs salt is one or more of CsNO3, Cs2CO3, CsCl and Cs2SO4; The content of the additive 1 is 1 wt%~10 wt%.

3. The method according to claim 1, characterized in that In step (1), the Zn salt is one or more of Zn(NO3)2·6H2O, [ZnCO3]2·[Zn(OH)2]3, ZnCl2 and ZnSO4; La salt is one or more of La(NO3)3, La2(CO3)3·xH2O, LaCl3 and La2(SO4)3; The Co salt is one or more of Co(NO3)2·6H2O, CoCO3, CoCl2 and CoSO4·H2O; The content of the additive 2 is 1 wt%~10 wt%.

4. The method according to claim 1, characterized in that In step (1), the heating reflux reaction temperature is 50-100° C., and the reflux reaction time is 3-5 h.

5. The method according to claim 1, characterized in that: In step (1), the calcination temperature is 350°C to 800°C, and the calcination time is 3 h to 8 h.

6. The method according to claim 1, characterized in that In step (2), the Ru salt is one or more of RuCl3, Ru(acac)3 and Ru(NO)(NO3)3; the Ru content is 0.5 wt%~5.0 wt%.

7. The method according to claim 6, characterized in that In step (2), the amount of urea or N-phenylurea added is 10-50 times the mass of the Ru salt.

8. The method according to claim 1, characterized in that: In step (2), the heating reflux reaction temperature is 50-100° C., and the reflux reaction time is 8-12 h.

9. The method according to claim 1, characterized in that: In step (2), the calcination temperature is 350°C to 800°C, and the calcination time is 3 h to 12 h.

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