CN114570417B

CN114570417B - Catalyst for preparing butene from n-butanol, preparation method thereof and method for preparing butene

Info

Publication number: CN114570417B
Application number: CN202210295493.0A
Authority: CN
Inventors: 张建安; 齐学进; 吴晶; 吴鹏飞; 张福春; 周玉杰; 刘宏娟; 阿斯蒂玛·宾特·阿卜杜勒·阿齐兹; 刘利南; 郑淑欣; 苏里哈蒂马西拉·阿卜杜·瓦夫提; 努尔赛伊拉·扎里尔; 杨志亮
Original assignee: Tsinghua University; Palm Oil Research and Development Board
Current assignee: Tsinghua University; Palm Oil Research and Development Board
Priority date: 2022-03-23
Filing date: 2022-03-23
Publication date: 2023-06-27
Anticipated expiration: 2042-03-23
Also published as: CN114570417A

Abstract

The invention discloses a catalyst for preparing butene from n-butanol, a preparation method thereof and a method for preparing butene, wherein the catalyst is Zn and Co modified ZSM-5. Therefore, the catalyst is used in the reaction for preparing the butene by dehydrating the n-butanol, has higher butanol conversion rate and higher butene selectivity, can be used in the dehydration reaction under the low-temperature condition, and has the advantage of reducing energy consumption. In addition, the catalyst has the advantages of high stability and long service life.

Description

Catalyst for preparing butene from n-butanol, preparation method thereof and method for preparing butene

Technical Field

The invention belongs to the field of biochemical engineering, and particularly relates to a catalyst for preparing butene from n-butanol, a preparation method thereof and a method for preparing butene.

Background

Currently, due to the rapid development of the aviation industry, the increasing demand for aviation fuels, non-renewable fossil resources and increasingly serious environmental problems have led to the search for technologies for preparing bio-aviation kerosene from renewable biomass resources. The biological aviation kerosene has the characteristics of being renewable and environment-friendly, and is a product with excellent performance for replacing or supplementing fossil energy. Palm is a renewable biomass resource rich in southeast Asian countries, palm oil production from palm is an important palm industry in southeast Asian countries, palm empty fruit strings (Empty Fruit Bunch, EFB) are the most main waste of the palm industry, and generally, the use of EFB is mainly used for preparing fertilizer after boiler burning or combustion, but combustion not only brings serious environmental pollution, but also wastes biomass resource of the palm empty fruit strings, so searching for a new way of using EFB becomes a research hot spot for people. The EFB contains cellulose, hemicellulose and lignin, wherein the cellulose and the hemicellulose can be degraded into reducing sugar, products with high added value such as biochemistry, medicine, energy sources and the like are prepared through microbial fermentation, cellulose and hemicellulose hydrolysate are obtained after the EFB is pretreated, biological butanol is prepared through microbial fermentation, and the biological butanol is subjected to catalytic dehydration, polymerization and hydrogenation to prepare the biological aviation kerosene for aviation industry. The process can utilize renewable biomass resource EFB as a raw material, does not depend on coal and petroleum resources, has renewable property, and is environment-friendly, so that the process has great development prospect and remarkable economic and social benefits. In the process of preparing the biological aviation kerosene by using EFB, the preparation of the butene by using the catalytic dehydration of the biological butanol is one of the key technologies and is also an important guarantee for further production of the biological aviation kerosene, so that the development of a catalyst with high catalytic efficiency is a key technical challenge in the process of preparing the butene by using the biological butanol.

The existing catalyst for butanol dehydration reaction has the defects of high reaction temperature, high energy consumption, lower butene selectivity, more byproducts and the like. Therefore, there is a need for an improved catalyst for the preparation of butenes by the dehydration of n-butanol.

Disclosure of Invention

The present invention aims to improve at least to some extent at least one of the above technical problems.

In order to solve the technical problems, the invention provides a catalyst for preparing butene from n-butanol, which is Zn and Co modified ZSM-5. Therefore, the catalyst is used in the reaction for preparing the butene by dehydrating the n-butanol, has higher butanol conversion rate and higher butene selectivity, can be used in the dehydration reaction under the low-temperature condition, and has the advantage of reducing energy consumption. In addition, the catalyst has the advantages of high stability and long service life.

The present invention also provides a process for preparing the catalyst described hereinbefore, which comprises: ZSM-5 and Zn-containing ²⁺ 、Co ²⁺ Is mixed with the solution of the above components to carry out hydrothermal reaction; and (3) carrying out solid-liquid separation on the product of the hydrothermal reaction, and roasting the separated solid to obtain the catalyst. Thus, the process has all of the features and advantages of the catalysts described hereinabove and will not be described in detail herein. In addition, the method has the advantages of simple operation, low production cost and the like.

In addition, the method for preparing the catalyst can also have the following additional technical characteristics:

the Zn-containing alloy comprises Zn ²⁺ 、Co ²⁺ The solution of (2) is a solution containing zinc nitrate and cobalt nitrate; in the solution containing zinc nitrate and cobalt nitrate, the content of the zinc nitrate is 0.5-1.5wt%, and the content of the cobalt nitrate is 2-4wt%.

The ZSM-5 and the Zn-containing alloy ²⁺ 、Co ²⁺ The solid-to-liquid ratio of the solution of (C) was 1:10g/ml.

The temperature of the hydrothermal reaction is 130-180 ℃; the hydrothermal reaction time is 2-6 hours; the roasting temperature is 500-700 ℃.

The invention also provides a method for preparing butene, which comprises the step of using the catalyst to dehydrate n-butanol to obtain butene. Thus, the process has all of the features and advantages of the catalysts described above and will not be described in detail herein. In general, the use of the above catalyst can provide a dehydration reaction with a higher butanol conversion and a higher butene selectivity, and the dehydration reaction can be performed at a low temperature, with the advantage of reducing energy consumption.

In addition, the method for preparing butene can also have the following additional technical characteristics:

the method for preparing butene comprises the following steps: heating and gasifying the n-butanol to obtain gasified n-butanol; and (3) contacting the gasified n-butanol with the catalyst to enable the gasified n-butanol to undergo a dehydration reaction so as to obtain butene.

The dehydration reaction is carried out in a fixed bed tubular reactor.

The dehydration reaction is carried out at a temperature of 250-300 ℃; the particle size of the catalyst is 20-40 meshes; the mass airspeed of the gasified n-butanol is 1h ^-1 。

According to an embodiment of the invention, the reacting further comprises activating the catalyst prior to contacting the vaporized n-butanol with the catalyst.

Further, the activation treatment is as follows: heating the catalyst for 2 hours at a temperature of 450 ℃ under the protection of inert gas;

further, after the activation treatment, the method further includes a step of cooling the catalyst to lower the temperature of the catalyst to the temperature of the dehydration reaction.

Drawings

FIG. 1 is a flow chart of a method of preparing a catalyst in the present invention;

FIG. 2 is a scanning electron microscope image of ZSM-5;

FIG. 3 is a scanning electron microscope image of 1% Zn-ZSM-5;

FIG. 4 is a scanning electron microscope image of 3% Co-ZSM-5;

FIG. 5 is a scanning electron microscope image of 1% Zn-3% Co-ZSM-5;

FIG. 6 is a XPS total spectrum of 1% Zn-3% Co-ZSM-5;

FIG. 7 is a graph of the service life of 1% Zn-3% Co-ZSM-5 and ZSM-5 as catalysts.

Detailed Description

Embodiments of the present application are described in detail below. The embodiments described below are exemplary only for the purpose of illustrating the present application and are not to be construed as limiting the present application. The examples are not to be construed as limiting the specific techniques or conditions described in the literature in this field or as per the specifications of the product. The reagents used were not manufacturer-identified and were all commercially available conventional products.

The present application is made based on the findings of the inventors regarding the following facts and problems: the inventor discovers that the existing catalyst for preparing the butene by dehydrating the butanol has the defects of low butanol conversion rate, low butene selectivity, short service life, easy deactivation and the like, and the reaction process needs to be carried out at a higher temperature, so that the energy consumption is high and the equipment requirement is high.

In order to solve the technical problems, the invention provides a catalyst for preparing butene from n-butanol, which is Zn and Co modified ZSM-5. The catalyst is used in the reaction of preparing butene through n-butanol dehydration, has higher butanol conversion rate and higher butene selectivity, can be used in dehydration reaction under low temperature, and has the advantage of reducing energy consumption. In addition, the catalyst has the advantages of high stability and long service life.

The present invention also provides a process for preparing the catalyst described hereinbefore, with reference to figure 1, which process comprises:

s100, ZSM-5 and Zn ²⁺ 、Co ²⁺ Is mixed with the solution of the above components to carry out hydrothermal reaction;

according to an embodiment of the present invention, the Zn-containing alloy comprises Zn ²⁺ 、Co ²⁺ The solution of (2) is a solution containing zinc nitrate and cobalt nitrate;

in the solution containing zinc nitrate and cobalt nitrate, the content of the zinc nitrate is 0.5-1.5wt%, and the content of the cobalt nitrate is 2-4wt%.

Illustratively, the zinc nitrate may be present in the solution containing zinc nitrate, cobalt nitrate in an amount of 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1.0wt%, 1.1wt%, 1.2wt%, 1.3wt%, 1.4wt%, 1.5wt%, and the cobalt nitrate may be present in an amount of 2wt%, 2.1wt%, 2.2wt%, 2.3wt%, 2.4wt%, 2.5wt%, 2.6wt%, 2.7wt%, 2.8wt%, 2.9wt%, 3wt%, 3.1wt%, 3.2wt%, 3.3wt%, 3.4wt%, 3.5wt%, 3.6wt%, 3.7wt%, 3.8wt%, 3.9wt%, 4wt%.

The zinc nitrate and the cobalt nitrate can be dissolved in water with certain mass respectively or simultaneously by a person skilled in the art, and the Zn-containing solution can be simply obtained by adjusting the mass of the added zinc nitrate and cobalt nitrate to ensure that the content of the zinc nitrate and cobalt nitrate in the prepared solution is the content ²⁺ 、Co ²⁺ Is a solution of (a) and (b).

The ZSM-5 and the Zn-containing alloy ²⁺ 、Co ²⁺ The solid-to-liquid ratio of the solution of (2) is 1:10g/ml, and the solid-to-liquid ratio refers to the volume ratio of solid mass to liquid.

According to some embodiments of the invention, ZSM-5 has a silica-alumina ratio of 38.

According to some embodiments of the invention, the temperature of the hydrothermal reaction may be 130-180 ℃, e.g., 130 ℃, 135 ℃, 140 ℃, 145 ℃, 150 ℃, 160 ℃, 165 ℃, 170 ℃, 175 ℃, 180 ℃;

the hydrothermal reaction time may be 2 to 6 hours, for example, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours.

According to some embodiments of the invention, the hydrothermal reaction may be performed in a hydrothermal reaction vessel.

S200, carrying out solid-liquid separation on the product of the hydrothermal reaction, and roasting the separated solid to obtain the catalyst.

According to an embodiment of the present invention, solid-liquid separation includes: and (3) carrying out centrifugal filtration treatment on the reaction product of the hydrothermal reaction so as to separate solid and liquid of the reaction product and obtain a solid product. The solid product obtained by the centrifugal filtration treatment is then washed. The solvent for washing the solid product may be water. The number of times of washing is not limited in the present invention, and may be one time, two times, three times or more.

Further, after the solid-liquid separation of the product of the hydrothermal reaction, the method further comprises a step of drying the separated solid; the invention does not limit the drying temperature and drying time, and the person skilled in the art can adjust the temperature and drying time according to the requirements, so long as the purpose of removing the solvent can be achieved through drying treatment. Illustratively, the temperature of the drying may be 120℃and the time of the drying may be 12 hours.

Further, after the drying treatment, the dried solid product is subjected to roasting treatment, so that Zn and Co modified ZSM-5 can be obtained.

According to some embodiments of the invention, the firing temperature is 500-700 ℃, e.g., 500 ℃, 550 ℃, 600 ℃, 650 ℃, 700 ℃.

The calcination treatment may be performed in a muffle furnace. The muffle furnace may be heated to the firing process temperature at a rate of rise and then held at the firing temperature for a period of time. According to some embodiments of the invention, the temperature increase rate may be 5 ℃/min. After the temperature is raised to the temperature of the roasting treatment, the muffle furnace can be kept at the roasting temperature for 5 hours, but the method is not limited to the above, and the temperature keeping time can be adjusted according to actual conditions by a person skilled in the art.

Thus, the process has all of the features and advantages of the catalysts described above and will not be described in detail herein. In general, the catalyst prepared by the method is used in the reaction for preparing the butene by dehydrating the n-butanol, has higher butanol conversion rate and higher butene selectivity, and the dehydration reaction can be performed under the low-temperature condition, thereby having the advantage of reducing energy consumption. In addition, the method has the advantages of simple operation, low production cost and the like.

The invention also provides a method for preparing butene, which comprises the step of using the catalyst to dehydrate n-butanol to obtain butene. Thus, the process has all of the features and advantages of the catalysts described above and will not be described in detail herein. In general, the catalyst of the present invention can make dehydration reaction have high butanol conversion rate and high butene selectivity, and the dehydration reaction can be performed at low temperature, with the advantage of reduced energy consumption.

According to some embodiments of the invention, the method of producing butene comprises:

s300, heating and gasifying the n-butanol to obtain gasified n-butanol

According to some embodiments of the invention, the dehydration reaction may be performed in a fixed bed tubular reactor.

The n-butanol is heated and gasified, so that the contact area of the n-butanol and the catalyst can be enhanced, and the catalytic effect is further improved. According to some embodiments of the invention, in this step, the n-butanol solution may be heated to gasify to obtain gasified n-butanol. The n-butanol solution refers to an aqueous solution of n-butanol, and the content of n-butanol in the n-butanol solution is not limited in the present invention, for example, the content of n-butanol in the n-butanol solution may be 80wt%, but is not limited thereto, and one skilled in the art may adjust according to the use requirement.

S400, contacting the gasified n-butanol with the catalyst to enable the gasified n-butanol to undergo a dehydration reaction to obtain butene

Further, the dehydration reaction is performed at a temperature of 200-300 ℃, and exemplary, the temperature of the dehydration reaction may be 200 ℃, 210 ℃, 220 ℃, 230 ℃, 240 ℃, 250 ℃, 260 ℃, 270 ℃, 280 ℃, 290 ℃, 300 ℃;

the particle size of the catalyst is 20-40 meshes; therefore, the catalyst can have higher specific surface area, the contact area of the catalyst and the n-butanol can be further increased, and the catalytic effect is further improved.

The mass space velocity of the gasified n-butanol can be 1h ^-1 . This can further improve the catalytic effect.

According to an embodiment of the invention, before the gasified n-butanol is contacted with the catalyst, the reaction further comprises: activating the catalyst; further, the activation treatment is as follows: the catalyst was heated under inert gas at a temperature of 450 ℃ for 2 hours. Thereby, the efficiency of the dehydration reaction can be further improved.

The invention will now be described with reference to specific examples, which are intended to be illustrative only and not limiting in any way.

Preparation example 1

Preparing a solution, wherein the mass fraction of zinc nitrate in the solution is 1%, the mass fraction of cobalt nitrate in the solution is 3%, and adding ZSM-5 according to the solid-liquid ratio of 1:10. Stirring and mixing, pouring the mixed solution into a hydrothermal reaction kettle, heating in a closed salt bath, preserving heat for 4 hours at 150 ℃, centrifugally filtering a solid-liquid mixture after the reaction is finished, repeatedly cleaning with deionized water, drying for 12 hours at 120 ℃, placing the mixture into a muffle furnace for roasting at 600 ℃, and preserving heat for 5 hours at a heating rate of 5 ℃/min. Obtaining Zn and Co modified ZSM-5:1% Zn-3% Co-ZSM-5.

It can be seen from FIG. 2 that the surface structure of unmodified ZSM-5 was relatively smooth, and from FIG. 5, the surface of Zn and Co modified ZSM-5 was roughened and particles were attached to the surface.

As can be seen from fig. 6, the XPS spectrum shows that the sample contains Zn, co, al, si and O, demonstrating successful loading of Zn and Co onto the ZSM-5 framework.

Preparation example 2

Preparing zinc nitrate solution with the mass fraction of 1%, and adding ZSM-5 according to the solid-liquid ratio of 1:10. Stirring and mixing, pouring the mixed solution into a hydrothermal reaction kettle, heating in a closed salt bath, preserving heat for 4 hours at 150 ℃, centrifugally filtering a solid-liquid mixture after the reaction is finished, repeatedly cleaning with deionized water, drying for 12 hours at 120 ℃, placing the mixture into a muffle furnace for roasting at 600 ℃, and preserving heat for 5 hours at a heating rate of 5 ℃/min. Obtaining Zn modified ZSM-5:1% Zn-ZSM-5.

As can be seen from FIG. 2, the surface structure of unmodified ZSM-5 was relatively smooth, and as can be seen from FIG. 3, the surface of Zn-modified ZSM-5 was roughened and particles were attached to the surface.

Preparation example 3

Preparing a cobalt nitrate solution with the mass fraction of 3 percent, and adding ZSM-5 according to the solid-liquid ratio of 1:10. Stirring and mixing, pouring the mixed solution into a hydrothermal reaction kettle, heating in a closed salt bath, preserving heat for 4 hours at 150 ℃, centrifugally filtering a solid-liquid mixture after the reaction is finished, repeatedly cleaning with deionized water, drying for 12 hours at 120 ℃, placing the mixture into a muffle furnace for roasting at 600 ℃, and preserving heat for 5 hours at a heating rate of 5 ℃/min. Obtaining Co modified ZSM-5:3% Co-ZSM-5.

It can be seen from FIG. 2 that the surface structure of unmodified ZSM-5 was relatively smooth, and from FIG. 4, the surface of Co-modified ZSM-5 was roughened and particles were attached to the surface.

Preparation example 4

Mn modified ZSM-5 catalyst was prepared by the method of preparation example 3, differing from preparation example 3 in that: preparing a manganese nitrate solution with the mass fraction of 4%, and obtaining Mn modified ZSM-5 by adopting other conditions as in preparation example 3: 4% Mn-ZSM-5.

Preparation example 5

The Zn modified ZSM-5 catalyst was prepared by the method of preparation example 2, except that: preparing a zinc nitrate solution with the mass fraction of 0.5%, and obtaining Zn modified ZSM-5 by adopting other conditions as in preparation example 2: 0.5% Zn-ZSM-5.

Preparation example 6

The Zn modified ZSM-5 catalyst was prepared by the method of preparation example 2, except that: preparing a zinc nitrate solution with the mass fraction of 1.5%, and obtaining Zn modified ZSM-5 by adopting other conditions as in preparation example 2: 1.5% Zn-ZSM-5.

Preparation example 7

Co-modified ZSM-5 catalyst was prepared by the method of preparation example 3, differing from preparation example 3 in that: preparing a cobalt nitrate solution with the mass fraction of 2%, and obtaining Co modified ZSM-5 by the same conditions as in preparation example 3: 2% Co-ZSM-5.

Preparation example 8

Co-modified ZSM-5 catalyst was prepared by the method of preparation example 3, differing from preparation example 3 in that: preparing a cobalt nitrate solution with the mass fraction of 4%, and obtaining Co modified ZSM-5 by the same conditions as in preparation example 3: 4% Co-ZSM-5.

Example 1

Tabletting, crushing and screening the catalyst 1% Zn-3% Co-ZSM-5 prepared in preparation example 1, selecting the catalyst size to be 20-40 meshes, loading the catalyst into a stainless steel fixed bed tubular reactor, supporting the lower layer by crushed ceramic chips, activating under the protection of nitrogen with the flow rate of 100mL/min, activating at 450 ℃ for 2 hours, cooling to 250 ℃ for catalytic reaction after the activation is completed, injecting 80% n-butanol solution into the reactor by a peristaltic pump, gasifying the n-butanol at the upper layer gasification section of the reactor, and controlling the mass airspeed of the n-butanol to be 1 hour ^-1 The gasified n-butanol reacts through a catalyst bed, a condensation recovery device is arranged at the outlet section of the reaction tube, unreacted n-butanol is recovered, and gas phase and liquid phase products are respectively collected for analysis. The gas phase product was analyzed by Shimadzu GC-2010 gas chromatography. The liquid phase was analyzed by liquid chromatography (HPLC). The butanol conversion was 96.52% and the butene selectivity was 94.39% in the n-butanol dehydration reaction by analytical calculation.

As can be seen from FIG. 7, when 1% Zn-3% Co-ZSM-5 and ZSM-5 are used as the catalyst, the service life of the 1% Zn-3% Co-ZSM-5 is obviously longer than that of the catalyst ZSM-5, and the butanol conversion rate and butene selectivity can still be up to more than 85% when the 1% Zn-3% Co-ZSM-5 is used for 8 hours.

Example 2

The catalyst prepared in preparation example 1, namely 1 percent of Zn-3 percent of Co-ZSM-5, is pressed, crushed and screened, the size of the catalyst is selected to be 20 to 40 meshes, the catalyst is filled into a stainless steel fixed bed tubular reactor, and the lower layer is arrangedSupporting with broken ceramic chip, activating under nitrogen protection with flow rate of 100mL/min, activating at 450deg.C for 2 hr, cooling to 300deg.C, performing catalytic reaction, injecting 80% n-butanol solution into the reactor by peristaltic pump, and gasifying in upper gasification stage of the reactor with mass airspeed of n-butanol of 1 hr ^-1 The gasified n-butanol reacts through a catalyst bed, a condensation recovery device is arranged at the outlet section of the reaction tube, unreacted n-butanol is recovered, and gas phase and liquid phase products are respectively collected for analysis. The gas phase product was analyzed by Shimadzu GC-2010 gas chromatography. The liquid phase was analyzed by liquid chromatography (HPLC). According to analysis and calculation, in the dehydration reaction of n-butanol, the butanol conversion rate is 96.69%, and the butene selectivity is 94.07%.

Example 3

Tabletting, crushing and screening the catalyst 1% Zn-3% Co-ZSM-5 prepared in preparation example 1, selecting the catalyst size to be 20-40 meshes, loading the catalyst into a stainless steel fixed bed tubular reactor, supporting the lower layer by crushed ceramic chips, activating under the protection of nitrogen with the flow rate of 100mL/min, activating at 450 ℃ for 2 hours, cooling to 250 ℃ for catalytic reaction after the activation is completed, injecting 80% n-butanol solution into the reactor by a peristaltic pump, gasifying the n-butanol at the upper layer gasification section of the reactor, and controlling the mass airspeed of the n-butanol to be 2 hours ^-1 The gasified n-butanol reacts through a catalyst bed, a condensation recovery device is arranged at the outlet section of the reaction tube, unreacted n-butanol is recovered, and gas phase and liquid phase products are respectively collected for analysis. The gas phase product was analyzed by Shimadzu GC-2010 gas chromatography. The liquid phase was analyzed by liquid chromatography (HPLC). The butanol conversion was 79.84% and the butene selectivity was 95.53% in the n-butanol dehydration reaction, as calculated by the analysis.

Example 4

The catalytic effect of 1% Zn-3% Co-ZSM-5 prepared in preparation example 1 as a catalyst for catalyzing the dehydration reaction of n-butanol to prepare butene was tested, and the dehydration reaction conditions of example 1 were referred to, except that: the dehydration reaction temperature was 200℃and the other conditions were the same as in example 1. After the reaction, the butanol conversion rate in the dehydration reaction of n-butanol is 83.86% and the butene selectivity is 86.84% by analytical calculation.

Comparative example 1

Tabletting, crushing and screening the catalyst 1% Zn-ZSM-5 in preparation example 2, selecting the catalyst size to be 20-40 meshes, loading the catalyst into a stainless steel fixed bed tubular reactor, supporting the lower layer by crushed ceramic chips, activating under the protection of nitrogen with the flow rate of 100mL/min, activating at 450 ℃ for 2 hours, reducing the reaction temperature to 250 ℃ after the activation is completed, carrying out catalytic reaction, injecting an n-butanol solution with the concentration of 80% into the reactor by a peristaltic pump, gasifying the n-butanol at the upper layer gasifying section of the reactor, and controlling the mass airspeed of the n-butanol to be 1 hour ^-1 The gasified n-butanol reacts through a catalyst bed, a condensation recovery device is arranged at the outlet section of the reaction tube, unreacted n-butanol is recovered, and gas phase and liquid phase products are respectively collected for analysis. The gas phase product was analyzed by Shimadzu GC-2010 gas chromatography. The liquid phase was analyzed by liquid chromatography (HPLC). According to analysis and calculation, in the dehydration reaction of n-butanol, the butanol conversion rate is 95.94%, and the butene selectivity is 91.11%.

Comparative example 2

Tabletting, crushing and screening 3% Co-ZSM-5 catalyst in preparation example 3, selecting catalyst size of 20-40 meshes, loading the catalyst into a stainless steel fixed bed tubular reactor, supporting the lower layer by crushed ceramic plates, activating under the protection of nitrogen with flow of 100mL/min, activating at 450 ℃ for 2h, cooling to 250 ℃ for catalytic reaction, injecting 80% n-butanol solution into the reactor by a peristaltic pump, gasifying the upper layer of the reactor, and controlling mass space velocity of n-butanol to be 1h ^-1 The gasified n-butanol reacts through a catalyst bed, a condensation recovery device is arranged at the outlet section of the reaction tube, unreacted n-butanol is recovered, and gas phase and liquid phase products are respectively collected for analysis. The gas phase product was analyzed by Shimadzu GC-2010 gas chromatography. The liquid phase was analyzed by liquid chromatography (HPLC). According to analysis and calculation, in the dehydration reaction of n-butanol, the butanol conversion rate is 91.43%, and the butene selectivity is 92.68%.

Comparative example 3

The 4% Mn-ZSM-5 prepared in preparation example 4 was tested as a catalyst for catalyzing the dehydration of n-butanol to prepare butene, and the dehydration reaction conditions were the same as in example 1 except that the types of the catalysts were different, and after the reaction, the analysis calculation was performed, the butanol conversion rate was 77.58% and the butene selectivity was 95.4% in the n-butanol dehydration reaction.

Comparative example 4

ZSM-5 was tested as a catalyst for catalyzing the dehydration of n-butanol to prepare butene, and the dehydration conditions were the same as in example 1 except that the types of the catalyst were different, and analysis and calculation were performed after the reaction, in the dehydration of n-butanol, the butanol conversion was 94.61%, and the butene selectivity was 83.92%.

As can be seen from fig. 7, the catalyst ZSM-5 has a significantly poorer service life, and the selectivity of butene is reduced to below 80% when the ZSM-5 is used for 3 hours.

Comparative example 5

The catalytic effect of 0.5% Zn-ZSM-5 prepared in preparation example 5 as a catalyst for catalyzing the dehydration of n-butanol to prepare butene was tested, and the dehydration reaction conditions were the same as in example 1 except that the types of the catalyst were different, and analysis calculation was performed after the reaction, in the dehydration reaction of n-butanol, the butanol conversion was 72.64%, and the butene selectivity was 93.11%.

Comparative example 6

The catalytic effect of 1.5% Zn-ZSM-5 prepared in preparation example 6 as a catalyst for catalyzing the dehydration of n-butanol to prepare butene was tested, and the dehydration reaction conditions were the same as in example 1 except that the types of the catalyst were different, and analysis calculation was performed after the reaction, in the dehydration reaction of n-butanol, the butanol conversion was 92.79%, and the butene selectivity was 70.86%.

Comparative example 7

The catalytic effect of 2% Co-ZSM-5 prepared in preparation example 7 as a catalyst for catalyzing the dehydration of n-butanol to prepare butene was tested, and the dehydration conditions were the same as in example 1 except that the types of the catalyst were different, and after the reaction, the analysis calculation was performed, the butanol conversion rate was 84.45% and the butene selectivity was 86.83% in the dehydration of n-butanol.

Comparative example 8

The catalytic effect of 4% Co-ZSM-5 prepared in preparation example 8 as a catalyst for catalyzing the dehydration of n-butanol to prepare butene was tested, and the dehydration conditions were the same as in example 1 except that the types of the catalyst were different, and after the reaction, the analysis calculation was performed, the butanol conversion rate was 93.46% and the butene selectivity was 79.89% in the dehydration of n-butanol.

From a comparison of examples 1-4, it is seen that when Zn and Co modified ZSM-5 was used as a catalyst for the dehydration of n-butanol to produce butene, there was a higher butanol conversion and higher butene selectivity. Further, when the mass space velocity of the n-butanol is 1h ^-1 And meanwhile, when the dehydration reaction temperature is between 250 and 300 ℃, zn and Co modified ZSM-5 are used as catalysts, the butanol conversion rate is up to more than 96%, and the butene selectivity is up to more than 94%, so that the catalyst has higher butanol conversion rate and higher butene selectivity.

As is evident from the comparison of example 1 with comparative examples 1-8, the catalytic effect of Zn and Co modified ZSM-5 as catalyst was significantly higher than that of one of Zn and Co modified ZSM-5 as catalyst, that of other metal Mn modified ZSM-5 as catalyst, and that of unmodified ZSM-5 as catalyst.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.

Claims

1. A process for producing butene which comprises dehydrating n-butanol using a catalyst to obtain butene,

the catalyst is Zn and Co modified ZSM-5,

the preparation steps of the catalyst comprise:

ZSM-5 and Zn-containing ²⁺ 、Co ²⁺ Is mixed with the solution of the above components to carry out hydrothermal reaction;

carrying out solid-liquid separation on the product of the hydrothermal reaction, roasting the separated solid to obtain the catalyst,

the Zn-containing alloy comprises Zn ²⁺ 、Co ²⁺ The solution of (2) is a solution containing zinc nitrate and cobalt nitrate;

in the solution containing zinc nitrate and cobalt nitrate, the content of the zinc nitrate is 0.5-1.5wt percent, the content of the cobalt nitrate is 2-4wt percent,

the ZSM-5 and the Zn-containing alloy ²⁺ 、Co ²⁺ The solid-to-liquid ratio of the solution of (2) is 1:10g/ml,

the temperature of the hydrothermal reaction is 130-180 ℃;

the hydrothermal reaction time is 2-6 hours.

2. The method of claim 1, wherein the firing temperature is 500-700 ℃.

3. The method according to claim 1, characterized in that the method comprises:

heating and gasifying the n-butanol to obtain gasified n-butanol;

and (3) contacting the gasified n-butanol with the catalyst to enable the gasified n-butanol to undergo a dehydration reaction so as to obtain butene.

4. A process according to claim 3, wherein the dehydration reaction is carried out in a fixed bed tubular reactor.

5. The process according to claim 4, wherein the dehydration reaction is carried out at a temperature of 250-300 ℃;

the particle size of the catalyst is 20-40 meshes;

the mass space velocity of the gasified n-butanol is 1h ^-1 。

6. The method of claim 4, wherein prior to contacting the vaporized n-butanol with the catalyst, the reacting further comprises activating the catalyst;

the activation treatment includes: the catalyst was heated under inert gas at a temperature of 450 ℃ for 2 hours.

7. The method of claim 6, further comprising the step of cooling the catalyst after the activation treatment to reduce the temperature of the catalyst to the temperature of the dehydration reaction.