Catalyst for synthesizing gamma-butyrolactone from 1, 4-butanediol and preparation method of catalyst

Abstract

The invention discloses a catalyst for synthesizing gamma-butyrolactone from 1, 4-butanediol and a preparation method of the catalyst. The chemical formula of the catalyst is represented as Cu-Zn-Zr-Cr / SiO2. The active components of the catalyst comprise metallic, oxide or composite oxide of Cu, Zn, Zr, Cr and the like. Wherein Cu is the main active center of the catalyst, and the dispersion degree and anchoring position of Cu and the proportion of Cu0 / Cu + are determined by the components of Zn, Zr, Cr and the like and the confinement effect provided by SiO2. The catalyst has the characteristics that good catalytic performance is maintained under the condition of low Cr content, the conversion rate of 1, 4-butanediol reaches 99.7%, and the selectivity of gamma-butyrolactone reaches 99.4%; the particle size and distribution of Cu are optimized, and the contents of Cu0 and Cu + and the proportion of Cu0 / Cu + are kept stable under the hydrogen reaction condition, so that the service life of the catalyst is prolonged; the catalyst is simple in preparation process, free of precious metal and high in economical efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of catalysis, and mainly relates to a catalyst for dehydrogenating 1,4-butanediol to prepare gamma-butyrolactone and a preparation method thereof. Background Art

[0002] γ-Butyrolactone is an important intermediate in the synthesis of polyvinyl pyrrolidone, methionine, vitamin B1 and naofukang, and is also an effective ingredient in coatings, detergents and textile auxiliaries. The catalytic dehydrogenation of 1,4-butanediol to produce γ-butyrolactone is one of the more mature known synthetic methods.

[0003] The reaction of 1,4-butanediol catalytic dehydrogenation to γ-butyrolactone is usually carried out in the presence of hydrogen. Among common catalysts, the active component is mainly Cu, supplemented by additives such as Cr, Mn, Zn, Ba, Fe, and Pd (see Chinese patents CN1111168A, CN1304795A, CN1357409A CN1169428A, and CN1194268A). Among them, Cu-Cr catalyst is one of the earliest developed catalysts, and its advantages are stable performance and long life. However, Cr is extremely harmful to environmental pollution and human body. Therefore, the reduction and replacement of Cr in catalysts has long been one of the important research goals. However, the Cu-Zn and Cu-Zn-Al catalysts that have received attention in existing studies still have problems such as excessive Cu content, uneven Cu distribution, and easy agglomeration of Cu, which leads to poor long-term stability of the catalyst, poor selectivity, and high energy consumption for subsequent product separation.

[0004] Therefore, considering the technical cost and ecological environment, it is of great significance to develop a new type of efficient and low-toxic catalyst for the dehydrogenation of 1,4-butanediol to γ-butyrolactone. Summary of the invention

[0005] The invention provides a catalyst for efficiently catalyzing the dehydrogenation of 1,4-butanediol to prepare gamma-butyrolactone and a preparation method thereof.

[0006] The catalyst provided by the present invention has a chemical formula of Cu-Zn-Zr-Cr / SiO2, and is characterized in that the mass percentage of the Cu component (including Cu, Cu2O, and CuO) in the catalyst is 3 to 5%, the mass percentage of the ZnO in the catalyst is 10 to 15%, the mass percentage of the ZrO2 in the catalyst is 10 to 15%, the mass percentage of the Cr component (including Cr2O3 and CrO3) in the catalyst is 0.5 to 2%, and the mass percentage of the SiO2 is 63 to 76.5%.

[0007] The SiO2 component in the catalyst provides carrier support for the catalyst and confines the metal through regular molecular sieve pores to prevent metal agglomeration.

[0008] The Zr component in the catalyst strengthens the catalyst skeleton and can also adjust the acidity and alkalinity of the carrier SiO2.

[0009] The Zn and Cr components in the catalyst play a catalytic role in the dehydrogenation reaction and are also helpful in adjusting the electronic structure and dispersion of the Cu component.

[0010] The catalyst is applied to a hydrogen reaction system, and the added Zn, Cr, and Zr components help maintain the zero-valent copper (Cu) in the catalyst under a H2 atmosphere. 0 ) and copper (Cu + ) content, and Cu 0 / Cu + proportion.

[0011] The present invention provides a method for preparing a catalyst for dehydrogenating 1,4-butanediol to produce γ-butyrolactone, comprising the following steps:

[0012] A. Mix tetraethoxysilane, tetrapropylammonium hydroxide and deionized water, stir and place in an autoclave at 180-200°C for 68-72 hours; filter and dry to obtain a solid, place in a muffle furnace at 400-600°C for calcination for 2-6 hours to obtain SiO2 solid.

[0013] B. Mix copper nitrate, chromium nitrate and deionized water and stir for 1 hour.

[0014] C. The solid obtained in step A is mixed with the solution obtained in step B, and then ultrasonically treated for 0.5 to 1 h, and stirring is continued for 6 to 24 h.

[0015] D. The mixture obtained in step C is placed in an autoclave and treated at 180-200° C. for 36-72 hours; the solid is dried and filtered to obtain a solid, and the solid is placed in a muffle furnace and calcined at 400-600° C. for 2-6 hours.

[0016] E. Mix copper nitrate, zinc nitrate, zirconium nitrate and deionized water and stir for 1 hour.

[0017] F. The solid obtained in step D is immersed in the solution obtained in step E, and ammonia water with a concentration of 0.8 to 1 mol / L is added to react for 6 to 8 minutes.

[0018] h; filtering and drying to obtain a solid, placing it in a muffle furnace and roasting it at 400-600° C. for 2-6 hours, and then crushing and molding to obtain the catalyst for dehydrogenation of 1,4-butanediol to produce γ-butyrolactone.

[0019] The implementation method of the present invention is as follows: the catalyst of the present invention is applied to the reaction of dehydrogenating 1,4-butanediol to produce γ-butyrolactone. The reaction is carried out in a fixed bed reactor. First, the catalyst is loaded into the constant temperature zone of the bed, and a reducing gas is introduced to activate the catalyst; the catalyst bed is adjusted to the temperature required for the reaction, and 1,4-butanediol and H2 are introduced at a certain molar ratio to carry out a dehydrogenation reaction; the reaction products are collected in real time, and the products are quantitatively analyzed using gas chromatography.

[0020] Advantages of the present invention: Compared with the commonly used Cu-Cr dehydrogenation catalyst, the Cr content in the catalyst of the present invention is significantly reduced (0.5%), which reduces the risk of poisoning during the catalyst preparation process. The support of Zn, Cr, Zr additives and SiO2 carrier optimizes the particle size and distribution of Cu in the catalyst. 0 and Cu + The content and Cu 0 / Cu + The ratio of 2-H2O to 2-H2O is kept stable, which helps to ensure the life of the catalyst (it has been running stably for more than 100 hours). The catalyst preparation process is simple, the raw materials are cheap, no precious metals are contained, and the manufacturing cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The data shown are the 1,4-butanediol conversion rate and the selectivity to γ-butyrolactone of the catalyst described in Example 1 in the real-time reaction under the reaction conditions of 1,4-butanediol dehydrogenation to γ-butyrolactone for 100 hours. DETAILED DESCRIPTION

[0022] Embodiment 1:

[0023] A. Mix 3.1 g of tetraethoxysilane, 2.4 g of tetrapropylammonium hydroxide, and 6 mL of deionized water and stir for 1 h, then place in an autoclave and treat at 180°C for 72 h; after separation, place the solid in an oven at 100°C for 12 h and calcine in a muffle furnace at 550°C for 4 h to obtain SiO2 solid.

[0024] B. Mix 0.09 g copper nitrate, 0.02 g chromium nitrate, and 4 mL deionized water and stir for 1 h.

[0025] C. The SiO2 solid obtained in step A was mixed with the solution obtained in step B, and then ultrasonically treated for 1 hour, and then continued to stir for 24 hours.

[0026] D. The mixture obtained in step C was placed in an autoclave and treated at 180° C. for 72 h. After separation, the solid was placed in an oven for drying at 100° C. for 12 h and then calcined in a muffle furnace at 550° C. for 4 h.

[0027] E. Dissolve 0.06 g copper nitrate, 0.43 g zinc nitrate, and 0.56 g zirconium nitrate in deionized water.

[0028] F. Immerse the solid obtained in step D in the solution obtained in step E; add 50 mL of 1 mol / L ammonia water, react for 8 hours, and filter; after separation, dry the solid in an oven at 100° C. for 12 hours and calcine in a muffle furnace at 400° C. for 4 hours;

[0029] After crushing and tableting, the Cu-Zn-Zr-Cr / SiO2 catalyst was obtained. The contents of the components in the catalyst are shown in Table 1.

[0030] Embodiment 2:

[0031] The preparation method is the same as that of Example 1, except that the amount of the metal salt used in step B is: 0.03 g of copper nitrate, 0.08 g of chromium nitrate, and the contents of the components in the catalyst are shown in Table 1.

[0032] Embodiment 3:

[0033] The preparation method is the same as that of Example 1, except that the amount of the metal salt used in step E is 0.06 g of copper nitrate, 0.29 g of zinc nitrate, and 0.56 g of zirconium nitrate. The contents of the components in the catalyst are shown in Table 1.

[0034] Embodiment 4:

[0035] The preparation method is the same as that of Example 1, except that the amount of the metal salt used in step E is 0.06 g of copper nitrate, 0.43 g of zinc nitrate, and 0.37 g of zirconium nitrate. The contents of the components in the catalyst are shown in Table 1.

[0036] Embodiment 5:

[0037] The preparation method is the same as that of Example 1, except that in step D, the mixture is treated in an autoclave at 200° C. for 36 h.

[0038] Comparative Example 1:

[0039] This example is implemented to verify the effect of SiO2. The catalyst is prepared by coprecipitation method. The metal salts of Cu, Zn, Zr and Cr in the same amount as in Example 1 are mixed and dissolved in deionized water. After sufficient mixing, 1 mol / L ammonia solution is added for coprecipitation reaction to obtain a catalyst precursor; the catalyst precursor is placed in an autoclave and treated under the same conditions as in Example 1. The difference between this example and Example 1 is that the catalyst does not contain any components related to SiO2. The contents of each component in the catalyst are shown in Table 1.

[0040] Comparative Example 2:

[0041] This example is carried out to verify the effect of trace Cr. The preparation process is the same as that of Example 1, except that chromium nitrate is not added in step B. The contents of each component in the catalyst are shown in Table 1.

[0042] Comparative Example 3:

[0043] This example is implemented to verify the necessity of hydrothermal treatment in an autoclave. The preparation method is the same as that in Example 1, except that the treatment in step D is changed to immersion for 12 hours followed by filtration, drying in an oven at 100°C for 12 hours, and calcination in a muffle furnace at 550°C for 4 hours.

[0044] Comparative Example 4:

[0045] This example is implemented to verify the necessity of adding the Cu component in two steps. The preparation method is the same as that of Example 1, except that the amount of copper nitrate in step A is changed to 0.15 g; and the amount of copper nitrate in step E is changed to 0.

[0046] Catalyst application results

[0047] Weigh 1g of catalyst and load it into the constant temperature layer of the fixed bed reactor. Pass H2-N2 mixed gas with 20% H2 into the reactor, and reduce the catalyst at 280℃ for 5h. Pass 1,4-butanediol and H2 into the reactor for reaction. The feed rate of 1,4-butanediol is 2mL / h, the molar ratio of H2 to 1,4-butanediol is 20:1, and the reaction temperature and pressure are shown in Table 2. After the reaction is completed, the liquid product is collected, and the concentration of each component in the product is analyzed by gas chromatography, and the conversion rate of 1,4-butanediol and the selectivity of γ-butyrolactone are calculated. The product analysis results are shown in Table 2.

[0048] Table 1: Mass percentage of each component in the catalyst

[0049] catalyst Cu composition (%) ZnO(%) <![CDATA[ZrO2(%)]]> Cr component (%) Example 1 5.0 15.0 15.0 0.5 Example 2 3.0 15.0 15.0 2.0 Example 3 5.0 10.0 15.0 0.5 Example 4 5.0 15.0 10.0 0.5 Example 5 5.0 15.0 15.0 0.5 Comparative Example 1 14.1 42.3 42.3 1.3 Comparative Example 2 5.0 15.0 15.0 0 Comparative Example 3 5.0 15.0 15.0 0.5 Comparative Example 4 5.0 15.0 15.0 0.5

[0050] Table 2: Reaction conditions and performance evaluation data of catalyst application

[0051] Case Temperature(℃) Pressure(MPa) BDO conversion rate (%) GBL selectivity (%) Example 1 260 0.3 99.7 99.4 Example 2 260 0.3 99.4 99.6 Example 3 260 0.3 98.7 99.5 Example 4 260 0.3 97.8 98.9 Example 5 260 0.3 99.1 99.6 Comparative Example 1 260 0.3 83.2 97.0 Comparative Example 2 260 0.3 79.1 96.7 Comparative Example 3 260 0.3 61.9 95.4 Comparative Example 4 260 0.3 74.9 96.4

[0052] * In the table, 1,4-butanediol is abbreviated as BDO and γ-butyrolactone is abbreviated as GBL.

Claims

1. A method for preparing a catalyst for dehydrogenating 1,4-butanediol to produce γ-butyrolactone, characterized in that: Here are the steps: A. Mix tetraethoxysilane, tetrapropylammonium hydroxide and deionized water, stir and place in an autoclave at 180-200°C for 68-72h; filter and dry to obtain a solid, place in a muffle furnace and calcine at 400-600°C for 2-6h. Obtain SiO2 solid; B. Mix copper nitrate, chromium nitrate and deionized water and stir for 1 hour; C. mixing the solid obtained in step A with the solution obtained in step B, ultrasonically treating for 0.5 to 1 h, and continuing stirring for 6 to 24 h; D. placing the mixture obtained in step C in an autoclave at 180-200° C. for 36-72 h; drying and filtering to obtain a solid, and calcining the solid in a muffle furnace at 400-600° C. for 2-6 h; E. Mix copper nitrate, zinc nitrate, zirconium nitrate and deionized water and stir for 1 hour; F. The solid obtained in step D is immersed in the solution obtained in step E, and ammonia water with a concentration of 0.8 to 1 mol / L is added to react for 6 to 8 hours; the solid is filtered and dried to obtain a solid, which is placed in a muffle furnace and roasted at 400 to 600° C. for 2 to 6 hours. After crushing and molding, the catalyst for dehydrogenation of 1,4-butanediol to prepare γ-butyrolactone is obtained.

2. The preparation method according to claim 1, characterized in that The tetraethoxysilane used in step A is replaced by silica sol, silicate or silane compound.

3. A catalyst for dehydrogenating 1,4-butanediol to produce γ-butyrolactone prepared according to the method of claim 1.

4. The catalyst prepared by the method according to claim 1, wherein the catalyst chemical formula is: Cu-Zn-Zr-Cr / SiO2; the mass percentage of the Cu component in the catalyst is 3-5% of the catalyst, the mass percentage of the ZnO in the catalyst is 10-15%, the mass percentage of the ZrO2 in the catalyst is 10-15%, the mass percentage of the Cr component in the catalyst is 0.5-2%, and the mass percentage of the SiO2 is 63-76.5%; the Cu component comprises Cu, Cu2O and / or CuO; the Cr component comprises Cr2O3 and / or CrO3.

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