CN114570417A

CN114570417A - Catalyst for preparing butene from n-butanol, preparation method of catalyst and method for preparing butene

Info

Publication number: CN114570417A
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: 2022-06-03
Anticipated expiration: 2042-03-23
Also published as: CN114570417B

Abstract

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

Description

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

Technical Field

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

Background

At present, due to the rapid development of the aviation industry, the demand for aviation fuel is increasing, and the non-renewable fossil resources and the increasingly serious environmental problems cause people to explore the technology for preparing the biological aviation fuel from the 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 an abundant renewable biomass resource in southeast Asia countries, palm oil produced by palm is an important palm industry in southeast Asia countries, palm Empty Fruit Bunch (EFB) is a main waste in palm industry, EFB is generally used for preparing fertilizer after being burned or combusted in a boiler, but combustion not only causes serious environmental pollution, but also wastes palm Empty Fruit Bunch biomass resources, so that a new path for EFB utilization is sought to become a hot point of research of people. The EFB contains cellulose, hemicellulose and lignin, wherein the cellulose and the hemicellulose can be degraded into reducing sugar, products with high added values such as biochemistry, medicine, energy and the like are prepared through microbial fermentation, for example, the EFB is pretreated to obtain cellulose and hemicellulose hydrolysate, the 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 the aviation industry. The process can utilize renewable biomass resources EFB as raw materials, does not depend on coal and petroleum resources, has the advantages of renewability and environmental friendliness, and therefore has great development prospect and remarkable economic and social benefits. In the process of preparing the biological aviation kerosene by using the EFB, the catalytic dehydration of the biological butanol for preparing the butylene is one of key technologies and is also an important guarantee for further producing the biological aviation kerosene, so that the development of a catalyst with high catalytic efficiency in the process of preparing the butylene by using the biological butanol becomes a key technical challenge.

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

Disclosure of Invention

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

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

The present invention also provides a process for preparing a catalyst as hereinbefore described, said process comprising: ZSM-5 with Zn²⁺、Co²⁺Mixing the solutions, and carrying out hydrothermal reaction;and carrying out solid-liquid separation on the product of the hydrothermal reaction, and roasting the solid obtained by separation to obtain the catalyst. Thus, the process has all the features and advantages of the catalyst described hereinbefore, which are not described in detail herein. In addition, the method also has the advantages of simple operation, low production cost and the like.

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

said Zn-containing²⁺、Co²⁺The solution of (1) 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 0.5-1.5 wt%, and the content of the cobalt nitrate is 2-4 wt%.

Said ZSM-5 and said Zn-containing²⁺、Co²⁺The solution (2) has a solid-to-liquid ratio of 1:10 g/ml.

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

The invention also provides a method for preparing butylene, which comprises the step of carrying out dehydration reaction on n-butanol by using the catalyst to obtain butylene. Thus, the process has all the features and advantages of the catalysts described hereinbefore and will not be described in any further detail. In general, the use of the catalyst can lead the dehydration reaction to have higher conversion rate of the butyl alcohol and higher selectivity of the butyl alcohol, and the dehydration reaction can be carried out under low temperature conditions, and also has the advantage of reducing energy consumption.

In addition, the process for preparing butenes according to the invention can also have the following additional technical features:

the method for preparing the butene comprises the following steps: heating and gasifying the n-butyl alcohol to obtain gasified n-butyl alcohol; and contacting the gasified n-butanol with the catalyst to enable the gasified n-butanol to carry out dehydration reaction to obtain the butene.

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

The dehydration reaction is carried out at the temperature of 250-300 ℃; the particle size of the catalyst is 20-40 meshes; said vaporizing n-butylThe mass space velocity of the alcohol 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 at 450 ℃ for 2 hours under the protection of inert gas;

further, after the activation treatment, the method further comprises a step of reducing the temperature of the catalyst so as to reduce the temperature of the catalyst to the temperature of the dehydration reaction.

Drawings

FIG. 1 is a flow diagram of a process for preparing a catalyst according to the present invention;

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

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

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

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

FIG. 6 is an XPS survey 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 following description of the embodiments is merely exemplary in nature and is in no way intended to limit the present disclosure. The examples, where specific techniques or conditions are not indicated, are to be construed according to the techniques or conditions described in the literature in the art or according to the product specifications. The reagents used are not indicated by manufacturers, and are all conventional products available on the market.

The present application is based on the discovery by the inventors of the following facts and problems: the inventor finds that the existing catalyst for preparing the butylene through butanol dehydration generally has the defects of low butanol conversion rate, low butylene selectivity, short service life, easy inactivation 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 butylene from n-butanol, wherein the catalyst is ZSM-5 modified by Zn and Co. The catalyst is used in the reaction of preparing the butylene by dehydrating the n-butyl alcohol, has higher conversion rate of the butylene and higher selectivity of the butylene, can be used for dehydration reaction at low temperature, and also has the advantage of reducing energy consumption. In addition, the catalyst also has the advantages of high stability and long service life.

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

s100, ZSM-5 and Zn-containing²⁺、Co²⁺Mixing the solutions, and carrying out hydrothermal reaction;

according to an embodiment of the invention, the Zn is contained²⁺、Co²⁺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 0.5-1.5 wt%, and the content of the cobalt nitrate is 2-4 wt%.

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

One skilled in the art can dissolve zinc nitrate and cobalt nitrate into water with certain mass respectively or simultaneously, and adjust the mass of the added zinc nitrate and cobalt nitrate to make the content of the zinc nitrate and cobalt nitrate in the prepared solution be the above-mentioned content, so that the Zn-containing solution can be obtained simply and conveniently²⁺、Co²⁺The solution of (1).

Said ZSM-5 and said Zn-containing²⁺、Co²⁺The solid-to-liquid ratio of the solution (2) is 1:10g/ml, and the solid-to-liquid ratio refers to the mass of a solid and the volume of a liquidAnd (4) the ratio.

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

According to some embodiments of the present invention, the temperature of the hydrothermal reaction may be 130-;

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

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

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

According to an embodiment of the invention, the solid-liquid separation comprises: and carrying out centrifugal filtration treatment on the reaction product of the hydrothermal reaction so as to separate the solid from the liquid of the reaction product and obtain a solid product. The solid product obtained after the centrifugal filtration treatment was subsequently washed. The solvent for washing the above solid product may be water. The number of washing times is not limited in the present invention, and may be one, two, three or more.

Further, after the solid-liquid separation is carried out on the product of the hydrothermal reaction, the method also comprises the step of drying the solid obtained by the separation; the invention does not limit the drying temperature and the drying time, and the skilled in the art can adjust the drying temperature and the drying time according to the requirements as long as the aim of removing the solvent through drying treatment can be achieved. For example, the temperature of the drying may be 120 ℃, and the time of the drying may be 12 hours.

Further, after drying treatment, roasting the dried solid product to obtain the Zn and Co modified ZSM-5.

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

The firing treatment may be performed in a muffle furnace. The muffle furnace may be raised to the firing temperature at a ramp rate and then held at the firing temperature for a period of time. According to some embodiments of the invention, the ramp rate may be 5 ℃/min. After raising the temperature to the roasting treatment, the muffle furnace may be maintained at the roasting temperature for 5 hours, but is not limited thereto, and the holding time may be adjusted by those skilled in the art according to the actual circumstances.

Thus, the process has all the features and advantages of the catalysts described hereinbefore and will not be described in any further detail. In general, the catalyst prepared by the method is used for the reaction of preparing the butylene by dehydrating the n-butyl alcohol, has higher conversion rate of the butylene and higher selectivity of the butylene, can be carried out at low temperature, and has the advantage of reducing energy consumption. In addition, the method also 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 carrying out dehydration reaction on n-butanol by using the catalyst to obtain the butene. Thus, the process has all the features and advantages of the catalysts described hereinbefore and will not be described in any further detail. In general, the catalyst of the invention can ensure that the dehydration reaction has higher conversion rate of the butyl alcohol and higher selectivity of the butyl alcohol, and the dehydration reaction can be carried out under low temperature condition, thereby having the advantage of reducing energy consumption.

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

s300, heating and gasifying the n-butyl alcohol to obtain gasified n-butyl alcohol

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

The n-butyl alcohol is heated and gasified, so that the contact area of the n-butyl alcohol and the catalyst can be increased, and the catalytic effect is improved. According to some embodiments of the invention, in this step, the n-butanol solution may be subjected to thermal gasification to obtain gasified n-butanol. The n-butanol solution is 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 80 wt%, but is not limited thereto, and may be adjusted by those skilled in the art according to the use requirement.

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

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

the particle size of the catalyst is 20-40 meshes; therefore, the catalyst has a higher specific surface area, the contact area of the catalyst and the n-butyl alcohol 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, prior to contacting the vaporized n-butanol with the catalyst, the reacting further comprises: activating the catalyst; further, the activation treatment is as follows: the catalyst was heated at 450 ℃ for 2 hours under an inert gas blanket. This can further improve the efficiency of the dehydration reaction.

Further, after the activation treatment, the method further comprises the step of reducing the temperature of the catalyst so as to reduce the temperature of the catalyst to the temperature of the dehydration reaction.

The invention will now be described with reference to specific examples, which are intended to be illustrative only and not to be 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 ZSM-5 is added according to the solid-to-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 ℃, after the reaction is finished, centrifugally filtering the solid-liquid mixture, repeatedly cleaning with deionized water, drying for 12 hours at 120 ℃, after completely drying, putting into a muffle furnace for roasting at 600 ℃, heating at the speed of 5 ℃/min, and preserving heat for 5 hours. Obtaining Zn and Co modified ZSM-5: 1% Zn-3% Co-ZSM-5.

As can be seen from fig. 2, the surface structure of unmodified ZSM-5 is relatively flat and smooth, and as can be seen from fig. 5, the surface of Zn and Co modified ZSM-5 becomes rough and particles adhere 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 the successful loading of Zn and Co onto the ZSM-5 framework.

Preparation example 2

Preparing a zinc nitrate solution with the mass fraction of 1%, and adding ZSM-5 according to the solid-to-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 ℃, after the reaction is finished, centrifugally filtering the solid-liquid mixture, repeatedly cleaning with deionized water, drying for 12 hours at 120 ℃, after completely drying, putting into a muffle furnace for roasting at 600 ℃, heating at the speed of 5 ℃/min, and preserving heat for 5 hours. Obtaining a Zn-modified ZSM-5: 1% of Zn-ZSM-5.

As can be seen from fig. 2, the surface structure of unmodified ZSM-5 is relatively flat and smooth, and as can be seen from fig. 3, the surface of Zn-modified ZSM-5 becomes rough and particles adhere to the surface.

Preparation example 3

Preparing a cobalt nitrate solution with the mass fraction of 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 ℃, after the reaction is finished, centrifugally filtering the solid-liquid mixture, repeatedly cleaning with deionized water, drying for 12 hours at 120 ℃, after completely drying, putting into a muffle furnace for roasting at 600 ℃, heating at the speed of 5 ℃/min, and preserving heat for 5 hours. Obtaining a Co-modified ZSM-5: 3% of Co-ZSM-5.

As can be seen from fig. 2, the surface structure of unmodified ZSM-5 is relatively flat and smooth, and as can be seen from fig. 4, the surface of Co-modified ZSM-5 becomes rough and particles adhere to the surface.

Preparation example 4

A Mn-modified ZSM-5 catalyst was prepared according to the method of preparation example 3, except that: preparing a manganese nitrate solution with the mass fraction of 4%, and finally obtaining the Mn modified ZSM-5 by the method with the other conditions being the same as those of the preparation example 3: 4% Mn-ZSM-5.

Preparation example 5

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

Preparation example 6

A Zn-modified ZSM-5 catalyst was prepared according to the method of preparation example 2, except that: preparing a zinc nitrate solution with the mass fraction of 1.5%, and finally obtaining the Zn modified ZSM-5 under the same conditions as the preparation example 2: 1.5% Zn-ZSM-5.

Preparation example 7

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

Preparation example 8

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

Example 1

Tabletting, crushing and screening the catalyst 1% Zn-3% Co-ZSM-5 prepared in the preparation example 1, selecting the size of the catalyst to be 20-40 meshes, loading the catalyst into a stainless steel fixed bed tubular reactor, supporting the lower layer by broken porcelain pieces, activating under the protection of nitrogen with the flow of 100mL/min, wherein the activation temperature is 450 ℃, activating for 2 hours, cooling to the reaction temperature of 250 ℃ to perform catalytic reaction after the activation is completed, injecting a n-butyl alcohol solution with the concentration of 80% into the reactor by a peristaltic pump, completing gasification in the upper gasification section of the reactor, and completing the gasification in the mass space velocity of the n-butyl alcoholIs 1h^-1And the gasified n-butanol is reacted through a catalyst bed layer, a condensation recovery device is arranged at the outlet section of the reaction tube to recover the unreacted n-butanol, and gas-phase and liquid-phase products are respectively collected for analysis. The gas product was analyzed by Shimadzu GC-2010 gas chromatography. The liquid phase was analyzed by liquid chromatography (HPLC). Through analysis and calculation, in the n-butanol dehydration reaction, the conversion rate of the butanol is 96.52 percent, and the selectivity of the butene is 94.39 percent.

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

Example 2

Tabletting, crushing and screening the catalyst 1% Zn-3% Co-ZSM-5 prepared in the preparation example 1, selecting the size of the catalyst to be 20-40 meshes, loading the catalyst into a stainless steel fixed bed tubular reactor, supporting the lower layer by broken porcelain pieces, activating under the protection of nitrogen with the flow of 100mL/min, wherein the activation temperature is 450 ℃, activating for 2 hours, cooling to the reaction temperature of 300 ℃ to perform catalytic reaction after the activation is completed, injecting a n-butyl alcohol solution with the concentration of 80% into the reactor by a peristaltic pump, and completing gasification in the upper gasification section of the reactor, wherein the mass space velocity of the n-butyl alcohol is 1 hour^-1And the gasified n-butanol is reacted through a catalyst bed layer, a condensation recovery device is arranged at the outlet section of the reaction tube to recover the unreacted n-butanol, and gas-phase and liquid-phase products are respectively collected for analysis. The gas product was analyzed by Shimadzu GC-2010 gas chromatography. The liquid phase was analyzed by liquid chromatography (HPLC). Through analysis and calculation, in the n-butyl alcohol dehydration reaction, the conversion rate of the butyl alcohol is 96.69%, and the selectivity of the butylene is 94.07%.

Example 3

Tabletting, crushing and screening the catalyst 1% of Zn-3% of Co-ZSM-5 prepared in the preparation example 1, selecting the size of the catalyst to be 20-40 meshes, putting the catalyst into a stainless steel fixed bed tubular reactor, supporting the lower layer by broken ceramic sheets, activating under the protection of nitrogen with the flow rate of 100mL/min, wherein the activation temperature is 450 ℃, activating for 2 hours, and reducing the temperature to 250 ℃ after the activation is finishedCarrying out catalytic reaction at the reaction temperature, injecting a solution of n-butyl alcohol with the concentration of 80 percent into the reactor by a peristaltic pump, and completing gasification in the upper gasification section of the reactor, wherein the mass space velocity of the n-butyl alcohol is 2h^-1The gasified n-butyl alcohol reacts through a catalyst bed layer, a condensation recovery device is arranged at an outlet section of the reaction tube to recover the unreacted n-butyl alcohol, and gas-phase and liquid-phase products are respectively collected to be analyzed. The gas product was analyzed by Shimadzu GC-2010 gas chromatography. The liquid phase was analyzed by liquid chromatography (HPLC). Through analysis and calculation, in the n-butanol dehydration reaction, the conversion rate of the butanol is 79.84%, and the selectivity of the butene is 95.53%.

Example 4

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

Comparative example 1

Tabletting, crushing and screening 1% of Zn-ZSM-5 catalyst in preparation example 2, selecting the size of the catalyst to be 20-40 meshes, putting the catalyst into a stainless steel fixed bed tubular reactor, supporting the lower layer by a broken porcelain piece, activating under the protection of nitrogen with the flow of 100mL/min, the activation temperature being 450 ℃, activating for 2h, cooling to the reaction temperature of 250 ℃ to perform catalytic reaction after the activation is completed, injecting an n-butyl alcohol solution with the concentration of 80% into the reactor by a peristaltic pump, and completing gasification in the upper gasification section of the reactor, wherein the mass space velocity of the n-butyl alcohol is 1h^-1And the gasified n-butanol is reacted through a catalyst bed layer, a condensation recovery device is arranged at the outlet section of the reaction tube to recover the unreacted n-butanol, and gas-phase and liquid-phase products are respectively collected for analysis. The gas product was analyzed by Shimadzu GC-2010 gas chromatography. The liquid phase was analyzed by liquid chromatography (HPLC). Through analysis and calculation, in the n-butanol dehydration reaction, the conversion rate of the butanol is 95.94%, and the selectivity of the butene is 91.11%.

Comparative example 2

For preparation examples3, tabletting, crushing and screening the catalyst 3% Co-ZSM-5, selecting the catalyst with the size of 20-40 meshes, putting the catalyst into a stainless steel fixed bed tubular reactor, supporting the lower layer by broken ceramic pieces, activating under the protection of nitrogen with the flow rate of 100mL/min, wherein the activation temperature is 450 ℃, activating for 2 hours, cooling to the reaction temperature of 250 ℃ to perform catalytic reaction after the activation is finished, injecting a n-butyl alcohol solution with the concentration of 80% into the reactor by a peristaltic pump, and finishing the gasification in the upper gasification section of the reactor, wherein the mass space velocity of the n-butyl alcohol is 1 hour^-1The gasified n-butyl alcohol reacts through a catalyst bed layer, a condensation recovery device is arranged at an outlet section of the reaction tube to recover the unreacted n-butyl alcohol, and gas-phase and liquid-phase products are respectively collected to be analyzed. The gas product was analyzed by Shimadzu GC-2010 gas chromatography. The liquid phase was analyzed by liquid chromatography (HPLC). Through analysis and calculation, in the n-butanol dehydration reaction, the conversion rate of the butanol is 91.43%, and the selectivity of the butene is 92.68%.

Comparative example 3

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

Comparative example 4

The catalytic effect of ZSM-5 as a catalyst for catalyzing the reaction of preparing butylene by dehydrating n-butanol was tested, the conditions of the dehydration reaction were the same as those in example 1, except that the types of the catalysts were different, and after the reaction, the conversion rate of butanol was 94.61% and the selectivity of butylene was 83.92% in the n-butanol dehydration reaction.

As can be seen from FIG. 7, the service life of the catalyst ZSM-5 is remarkably poor, and the selectivity of butene of the ZSM-5 is reduced to be below 80% when the catalyst 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 in a reaction for catalyzing dehydration of n-butanol to butene, the dehydration reaction conditions were the same as in example 1 except that the catalyst type was different, and analysis and calculation after the reaction showed that the conversion rate of butanol was 72.64% and the selectivity of butene was 93.11% in the n-butanol dehydration reaction.

Comparative example 6

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

Comparative example 7

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

Comparative example 8

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

As can be seen from comparison of examples 1 to 4, when Zn and Co modified ZSM-5 were used as a catalyst for preparing butene by dehydration of n-butanol, there was a higher conversion rate of butanol and a higher selectivity of butene. Further, when the mass space velocity of the n-butanol is 1h^-1Meanwhile, when the temperature of the dehydration reaction is 250-300 ℃, Zn and Co modified ZSM-5 is used as a catalyst, the conversion rate of the butanol is up to more than 96%, and the selectivity of the butene is up to more than 94%, so that the method can simultaneously have higher conversion rate of the butanol and higher selectivity of the butene.

As can be seen from the comparison between example 1 and comparative examples 1 to 8, the catalytic effect of the Zn and Co modified ZSM-5 as the catalyst is significantly higher than that of the Zn and Co modified ZSM-5 as the catalyst, that of the Mn modified ZSM-5 as the catalyst and that of the unmodified ZSM-5 as the catalyst.

In the description of the specification, reference to the description of "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" or the like 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 invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer 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, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims

1. The catalyst for preparing the butylene from the n-butanol is characterized by being ZSM-5 modified by Zn and Co.

2. A method of preparing the catalyst of claim 1, comprising:

ZSM-5 with Zn²⁺、Co²⁺Mixing the solutions, and carrying out hydrothermal reaction;

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

3. The method according to claim 2, wherein said Zn is contained²⁺、Co²⁺The solution of (1) is a solution containing zinc nitrate and cobalt nitrate;

4. The method of claim 3, wherein the ZSM-5 and the Zn-containing are present²⁺、Co²⁺The solution (2) has a solid-to-liquid ratio of 1:10 g/ml.

5. The method as claimed in claim 2, wherein the temperature of the hydrothermal reaction is 130-180 ℃;

the time of the hydrothermal reaction is 2-6 hours;

the roasting temperature is 500-700 ℃.

6. A process for producing butene, which comprises subjecting n-butanol to dehydration reaction using the catalyst of claim 1 to obtain butene.

7. The method of claim 6, wherein the method comprises:

heating and gasifying the n-butyl alcohol to obtain gasified n-butyl alcohol;

and contacting the gasified n-butanol with the catalyst to enable the gasified n-butanol to carry out dehydration reaction to obtain the butene.

8. The process according to claim 7, characterized in that the dehydration reaction is carried out in a fixed bed tubular reactor.

9. The method as claimed in claim 8, 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 airspeed of the gasified n-butanol is 1h^-1。

10. The method of claim 7, wherein the reacting further comprises activating the catalyst prior to contacting the vaporized n-butanol with the catalyst;

the activation treatment comprises: heating the catalyst at 450 ℃ for 2 hours under the protection of inert gas;

optionally, after the activation treatment, the method further comprises the step of reducing the temperature of the catalyst to a temperature at which the dehydration reaction is carried out.