CN114618487B

CN114618487B - Bimetal alloy microcrystal catalyst for hydrogenation preparation of cyclohexene

Info

Publication number: CN114618487B
Application number: CN202210513035.XA
Authority: CN
Inventors: 刘寿长; 刘立胜; 郑强勇
Original assignee: Beijing Runjing Future New Material Technology Co ltd
Current assignee: Beijing Runjing Future New Material Technology Co ltd
Priority date: 2022-05-12
Filing date: 2022-05-12
Publication date: 2023-01-31
Anticipated expiration: 2042-05-12
Also published as: CN114618487A

Abstract

The invention discloses a bimetal cyclohexene alloy microcrystal catalyst prepared by hydrogenation. The catalyst mainly comprises Ru-Zn alloy microcrystal or Ru-Zn alloy microcrystal, wherein the Ru-Zn alloy microcrystal comprises 98-80% of Ru and 2-20% of Zn by mass, the particle size range of the Ru-Zn alloy microcrystal is 2-8 nm measured according to TEM, and the activity index gamma of the catalyst is ₄₀ Is 60 to 180. The catalyst has high selectivity and high activity index, and is suitable for industrial application.

Description

Bimetal alloy microcrystal catalyst for hydrogenation preparation of cyclohexene

Technical Field

The invention relates to a catalyst for preparing cyclohexene by hydrogenation, in particular to a bimetallic alloy microcrystalline catalyst for preparing cyclohexene by hydrogenation and a preparation method and application thereof.

Background

The selective hydrogenation of benzene to cyclohexene has historically been considered nearly impossible to achieve on a large scale commercial scale due to the thermodynamic and kinetic disadvantages of this chemical reaction. Since swedish scholars detected cyclohexene by hydrogenation of benzene with Ni film catalysis for the first time in 1957, the industry of asahi formation company in japan was industrialized in 1989, and the development process was over 30 years. Over the last half century, extensive research has been conducted in countries around the world to further improve cyclohexene selectivity and yield.

The benzene selective hydrogenation catalytic technology has been monopolized by the Asahi Kasei Corp before the research and development of the catalytic problem group of Zhengzhou university. Research on selective hydrogenation catalysis technology by the Zhengzhou university topic group starts in 1998, a key core technology for preparing cyclohexene by benzene hydrogenation with high efficiency and controllability is developed aiming at the technical bottleneck of preparing cyclohexene by benzene, and industrial application is realized in 2010.

The downstream products of the cyclohexene, nylon 6 and nylon-66, prepared by benzene hydrogenation are called chinlon after melt spinning, and have high strength, wear resistance and rebound resilience. The catalyst technology realizes safe production, clean production and green production of cyclohexanone, caprolactam and adipic acid which are products from the sources of nylon 6 and nylon-66, and plays an important role in improving the cultural life of people and promoting the health level.

Chinese patent publication No. CN1984712A (application No. 200580023158. X) discloses a catalyst for cycloolefin production, which contains zirconia as a carrier and is composed of particles having an average primary particle diameter of 3nm to 50nm, and in which the volume of pores having a pore diameter in the range of 2.5nm to 15nm accounts for 50% by volume or more of the total volume of pores having a pore diameter in the range of 2nm to 150 nm. The catalyst has a particle size of 20m ² /g～300 m ² Specific surface area/g, in fact, the catalysts prepared in examples 1 and 2 had a surface area of 201 m ² G and 111 m ² Specific surface area in g. Chinese patent publication No. CN106140154A (application No. 201510184558.4) discloses a catalyst for preparing cyclohexene by selective hydrogenation of benzene, which consists of a zirconia carrier and an active metal component loaded on the zirconia carrier, wherein the catalyst has an average primary particle size of 10-50 nm and has a particle size of 10m ² /g～ 150m ² A specific surface area per gram, and the volume ratio of pores with a pore diameter in the range of 2nm to 15nm to pores with a pore diameter in the range of 2nm to 150nm in the catalyst is less than 50%, wherein the active metal component is ruthenium and/or a compound of ruthenium, and optionally zinc and/or a compound of zinc. The average crystal diameter of the ruthenium is 2nm to 15nm. The average particle diameter of the ruthenium metal particles supported on the catalyst was calculated by Transmission Electron Microscope (TEM) measurement. The cyclohexene selectivity is 76.5-82.8% when the benzene conversion rate is 50%. Both of these patent applications disclose catalysts which are supported on zirconia as a support. Prepared by loading active metal compounds on a zirconia carrier. Because the active components are solidified on the surface of the carrier and in the pore channels, reactants can not fully contact with the catalyst, and a target product cyclohexene produced by benzene hydrogenation can not be timelyThe catalyst is easy to be continuously hydrogenated into cyclohexane, so that the selectivity of cyclohexene is reduced due to mass transfer, and the industrial application of the supported catalyst is limited.

Patent application CN104941637B (application no 201510259968.0) discloses a metal catalyst which is an alloy of Ru and a transition metal M, M being one of Zn, fe, co. The catalyst is prepared by the following method: adding a ruthenium compound and a compound of a transition element M serving as precursors into diphenyl ether containing oleamide, and then injecting a strong reducing agent; adding a dispersing solvent, and then carrying out centrifugal separation to obtain the Ru-M alloy catalyst. From the TEM photograph, the particles having a particle size in the range of 1nm to 10nm were observed in the sample prepared in example 1. Thus, the Ru-M alloy catalyst of this patent application CN104941637B is a particle with a particle size distribution in the range of 1nm to 10 nm. The active specific surface area is 10m ² /g～30m ² (iv) g. The patent application does not give performance parameters for the catalyst prepared in example 1, but gives the catalytic performance of the catalyst of example 2. As can be seen from fig. 4, the benzene conversion was less than 45% when the reaction time was 15min, and less than or equal to 50% when the reaction time was 20min. Because the catalyst particles have different sizes, according to the Kelvin theorem, along with the extension of reaction time, small particles are dissolved, large particles are grown, and the activity selectivity of the catalyst is obviously reduced, thereby limiting the industrial application of the catalyst.

Therefore, there is a need to develop a new alloy catalyst for hydrogenation to cyclohexene with high selectivity and activity.

Disclosure of Invention

In view of the above, the invention provides a bimetal cyclohexene alloy microcrystalline catalyst prepared by hydrogenation. It has high selectivity, high activity and good stability, and can meet the requirements of industrial production.

The invention aims to provide a catalyst for preparing cyclohexene bimetal alloy microcrystal through hydrogenation, which mainly comprises or consists of Ru-Zn alloy microcrystal, wherein the Ru-Zn alloy microcrystal comprises 98-80% of Ru and 2-20% of Zn by mass, and the Ru-Zn alloy microcrystal is measured according to TEMThe particle diameter range is 2 nm-8 nm, and the activity index gamma of the catalyst ₄₀ Is 60 to 180.

When the specific surface area of the Ru-Zn alloy microcrystal is 40m ² /g～60m ² The activity index of the corresponding catalyst is 60-130 in g; when the specific surface area is 60m ² /g～80m ² The activity index of the corresponding catalyst is 130-180 in terms of/g. According to the invention, the pore volume of the Ru-Zn alloy crystallites is 0.10 cm ³ /g～0.35 cm ³ In terms of/g, preferably 0.13 cm ³ /g～0.29 cm ³ /g。

The Ru-Zn alloy crystallites have a particle size of from 2nm to 7nm, preferably from 2nm to 6nm, as measured by TEM.

The average crystallite diameter obtained by the Ru-Zn alloy microcrystal according to an XRD measuring method is 2 nm-5 nm, and preferably 2.5-4 nm.

According to the invention, the bi-metal alloy microcrystalline catalyst for hydrogenation preparation of cyclohexene contains inevitable impurities.

According to the invention, the hydrogenation cyclohexene bimetallic alloy microcrystalline catalyst does not contain a carrier.

According to the invention, the bimetal cyclohexene alloy microcrystalline catalyst prepared by hydrogenation is prepared by the following method: stirring and standing the alkali liquor and the salt liquor in a stirring kettle, and injecting the alkali liquor and the salt liquor into a high-pressure kettle for reduction, wherein the preparation of a water retention film is optionally included; wherein the alkali solution is Na compound alkali solution, and the salt solution is Zn compound salt solution and Ru compound solution. The reactants do not contain organic solvents.

According to the invention, the bimetal cyclohexene alloy microcrystalline catalyst prepared by hydrogenation is prepared by the following method: stirring and standing the alkali liquor and the salt liquor in a stirring kettle, and injecting the alkali liquor and the salt liquor into a high-pressure kettle for primary reduction to obtain a primary reduced Ru-Zn alloy microcrystal precursor; then optionally preparing a water retention film; then carrying out secondary reduction, and washing to obtain Ru-Zn alloy microcrystal, wherein the primary reduction is to carry out timing reduction reaction for 6-8 h when the hydrogen pressure is stabilized at 8-10 MPa and the temperature reaches 80-100 ℃; the secondary reduction is that the hydrogen pressure is stabilized at 6MPa to 8MPa, the time for reduction reaction is controlled at 4h to 6h after the temperature reaches 160 ℃ to 180 ℃.

The invention also aims to provide a preparation method of the cyclohexene bimetallic alloy microcrystalline catalyst by hydrogenation.

The invention also aims to provide the application of the bimetal cyclohexene alloy microcrystal catalyst prepared by hydrogenation in preparation of cyclohexene.

According to the catalyst of the present invention, when the benzene conversion rate is 40%, the activity index γ 40 of the catalyst is in the range of 60 to 180, preferably in the range of 100 to 170. The cyclohexene selectivity is in the range of 80% -89%.

The inventor discovers the change rule of the specific surface area and the catalyst activity index of the Ru-Zn alloy microcrystal of the invention through a large number of experiments, and discovers that the specific surface area of the Ru-Zn alloy microcrystal is 40m ² /g～60m ² The activity index (gamma 40) of the corresponding catalyst per gram is 60 to 130; the microcrystal specific surface area of Ru-Zn alloy is 60m ² /g～80m ² The activity index (. Gamma.40) per gram of the corresponding catalyst is 130 to 180.

The inventor discovers the optimal catalyst production reaction conditions through a large number of laboratory experiments and industrial production experiments, and invents a quantitative embedding method of Zn atoms in Ru crystal lattices, so as to prepare the hydrogenation cyclohexene bimetal alloy microcrystalline catalyst, namely the Ru-Zn alloy microcrystalline catalyst.

Advantageous effects

(1) The catalyst for preparing the cyclohexene bimetal alloy microcrystal through hydrogenation is a Ru-Zn alloy microcrystal which is in a crystalline structure and is not in an amorphous structure, so that the catalyst is stable in structure and low in temperature sensitivity, not only is the activity index of the catalyst improved, but also the service life of the catalyst is prolonged. Compared with Ru-Zn amorphous catalyst, the alloy microcrystalline catalyst provided by the invention has more excellent effect.

(2) According to the invention, zn atoms are quantitatively embedded, so that Zn in the generated Ru-Zn alloy microcrystal catalyst is not easy to precipitate and run off, and the improvement and the stability of the selectivity of the catalyst are ensured. Meanwhile, the growth speed of the Ru-Zn alloy microcrystal catalyst particles is reduced, the activity reduction speed of the catalyst is reduced in industrial application, and the stability of the activity is kept.

Drawings

FIG. 1 is an XRD pattern of the catalyst prepared in example 1;

FIG. 2 is a TEM image of a transmission electron microscope of the catalyst prepared in example 1;

FIG. 3 is an XRD pattern of the catalyst prepared in example 2;

FIG. 4 is a TEM image of a catalyst prepared in example 2;

FIG. 5 is an XRD pattern of the catalyst prepared in example 3;

FIG. 6 is a TEM image of a catalyst prepared in example 3;

FIG. 7 is an XRD pattern of the catalyst prepared in example 4;

FIG. 8 is a TEM image of a catalyst prepared in example 4;

FIG. 9 is an XRD pattern of the catalyst prepared in example 5;

FIG. 10 is a TEM image of a catalyst prepared in example 5;

FIG. 11 is an XRD pattern of the catalyst prepared in example 6;

FIG. 12 is a TEM image of a catalyst prepared in example 6;

FIG. 13 is an XRD pattern of the catalyst prepared in example 7;

FIG. 14 is a TEM image of a catalyst prepared in example 7;

FIG. 15 is a graph of the relationship between the specific surface area and the activity index of the catalyst of the present invention.

Detailed Description

The invention is further described below by means of specific embodiments, the advantages and features of which will become clearer as the description proceeds. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention, and that such changes and substitutions are intended to be within the scope of the invention.

The term "hydrogenation to cyclohexene bimetallic alloy microcrystalline catalyst" is interchangeable with the term "Ru — Zn alloy microcrystalline catalyst" and is the same catalyst. In practice, the hydrogenation to cyclohexene bimetallic alloy crystallite catalyst consists of Ru — Zn alloy crystallites, which may contain unavoidable impurities. The hydrogenation cyclohexene bimetallic alloy microcrystalline catalyst "consisting of Ru — Zn alloy crystallites" should not be understood as a hydrogenation cyclohexene bimetallic alloy crystallite catalyst consisting of Ru — Zn alloy crystallites only, but should be understood as a hydrogenation cyclohexene bimetallic alloy crystallite catalyst consisting essentially of Ru — Zn alloy crystallites and possibly containing unavoidable impurities. The hydrogenation cyclohexene bimetallic alloy microcrystalline catalyst does not contain a carrier, such as a zirconia carrier.

Through a large number of experimental researches, the inventor invents a method for quantitatively embedding Zn atoms in Ru crystal lattices, and prepares the cyclohexene bimetallic alloy catalyst through hydrogenation. The catalyst is of a nano-crystalline structure, so the catalyst is called microcrystal and is different from the existing ruthenium-zinc catalyst with an amorphous structure.

According to the invention, the catalyst mainly comprises or consists of Ru-Zn alloy microcrystal, wherein the Ru-Zn alloy microcrystal comprises 98-80% of Ru and 2-20% of Zn by mass, and the specific surface area of the Ru-Zn alloy microcrystal is 40m ² /g～80m ² Per g, when the specific surface area of the Ru-Zn alloy microcrystal is 40m ² /g～50m ² Corresponding to the catalyst activity index gamma in g ₄₀ 60 to 100 percent, when the specific surface area of the Ru-Zn alloy microcrystal is 50m ² /g～60m ² Corresponding to the catalyst activity index gamma in g ₄₀ 100 to 130; when the specific surface area is 60m ² /g～80m ² Corresponding to the catalyst activity index gamma in g ₄₀ Is 130 to 180.

According to the invention, the pore volume of the Ru-Zn alloy crystallites is 0.10 cm ³ /g～0.35 cm ³ In g, preferably 0.13 cm ³ /g～0.29 cm ³ /g。

The Ru-Zn alloy crystallites have a particle size of from 2nm to 8nm, preferably from 2nm to 7nm, or from 2nm to 6nm, or from 2nm to 5nm, as measured by TEM.

According to the invention, the bimetal cyclohexene alloy microcrystalline catalyst prepared by hydrogenation is prepared by the following method: stirring and standing the alkali liquor and the salt liquor in a stirring kettle, and injecting the alkali liquor and the salt liquor into a high-pressure kettle for reduction, wherein preparation of a water retention membrane is optionally included; wherein the alkali liquor is Na compound alkali liquor, and the salt liquor is Zn compound salt solution and Ru compound solution.

According to the invention, the bimetal cyclohexene alloy microcrystalline catalyst prepared by hydrogenation is prepared by the following method: stirring and standing the alkali liquor and the salt liquor in a stirring kettle, and injecting the alkali liquor and the salt liquor into a high-pressure kettle for primary reduction to obtain a primary reduced Ru-Zn alloy microcrystal precursor; then optionally preparing a stagnant water film; then carrying out secondary reduction, and washing to obtain Ru-Zn alloy microcrystal, wherein the primary reduction is to carry out timing reduction reaction for 6-8 h when the hydrogen pressure is stabilized at 8-10 MPa and the temperature reaches 80-100 ℃; the secondary reduction is that the hydrogen pressure is stabilized at 6MPa to 8MPa, the time for reduction reaction is controlled at 4h to 6h after the temperature reaches 160 ℃ to 180 ℃.

The invention also discloses a preparation method of the bimetal alloy microcrystalline catalyst for hydrogenation preparation of cyclohexene, wherein the bimetal alloy microcrystalline catalyst for hydrogenation preparation of cyclohexene is a Ru-Zn alloy microcrystalline catalyst, and the preparation method comprises the following steps:

the first step, the preparation and treatment of the Ru-Zn alloy microcrystalline catalyst precursor, comprises: preparing Na compound alkali solution, zn compound salt solution and Ru compound solution, stirring and standing;

and a second step, a reduction reaction, comprising: injecting the prepared Ru-Zn alloy microcrystalline catalyst precursor liquid into a high-pressure reaction kettle, stirring, standing, introducing nitrogen for gas replacement, introducing high-purity hydrogen after replacement, heating and stirring after the hydrogen pressure reaches 8-10 MPa, stabilizing the pressure at 8-10 MPa in the reaction process, and performing timed reduction reaction after the temperature reaches 80-100 ℃ for 6-8 h; then optionally standing for the second time and returning and washing;

optionally, in the third step, the preparation of the water retention film comprises: preparing ZnSO with deionized water ₄ Solution, the catalyst precursor feed liquid washed in the second step and the prepared ZnSO ₄ The solution is injected into the hastelloy mixer in sequenceStirring in a stirring kettle;

and step four, carrying out secondary reduction reaction, including: heating and stirring when the hydrogen pressure reaches 6-8 MPa, stabilizing the pressure at 6-8 MPa in the reaction process, and performing timed reduction reaction when the temperature reaches 160-180 ℃ for 4-6 h; cooling and reducing the pressure after the reduction is finished;

and fifthly, washing, namely, putting the Ru-Zn alloy microcrystal catalyst liquid obtained in the fourth step into a washing tank, and washing the catalyst liquid by using deionized water until the slurry is free of chloride ions and the pH value is 7-7.5, so as to obtain the Ru-Zn alloy microcrystal catalyst.

According to the invention, the preparation method of the cyclohexene bimetallic alloy microcrystalline catalyst by hydrogenation comprises the following steps:

the first step, the preparation and treatment of the Ru-Zn alloy microcrystalline catalyst precursor, comprises:

(1) In a proportioning tank, firstly injecting deionized water at 40-50 ℃, then sequentially injecting the prepared Na compound alkali solution, zn compound salt solution and Ru compound solution, and standing for 5-10 min;

(2) Injecting the mixed solution into a Hastelloy stirring kettle, and fully stirring for 30-40 min;

(3) After being stirred evenly, the mixture is kept stand for 10min to 20min;

and a second step, a reduction reaction, comprising:

(1) Pretreatment: injecting the prepared Ru-Zn alloy microcrystal catalyst precursor into a high-pressure reaction kettle, controlling the reaction temperature to be 40-50 ℃, and stirring for reaction for 8-10 h;

(2) Standing for the first time: stopping stirring, cooling and adjusting, controlling the temperature at 25-30 ℃, and then standing for 8-10 h;

(3) Primary reduction: firstly, introducing nitrogen into a high-pressure reaction kettle after standing for gas replacement; introducing high-purity hydrogen after replacement, heating and stirring after the hydrogen pressure reaches 8-10 MPa, stabilizing the pressure at 8-10 MPa in the reaction process, and performing timed reduction reaction after the temperature reaches 80-100 ℃ for 6-8 h;

(4) And (3) secondary standing: after the reaction is finished, reducing the temperature and the pressure, controlling the temperature to be 25-35 ℃ and the pressure to be 5-6 MPa, and standing for 10-12 h;

(5) Material returning and washing: washing the catalyst liquid with deionized water, and controlling the pH value to be 7-8 to obtain a primary reduced Ru-Zn alloy microcrystal catalyst precursor;

step three, preparing a water retaining membrane, comprising the following steps:

(1) Configuration of ZnSO ₄ Solution: preparing ZnSO with deionized water ₄ Solution of ZnSO ₄ The mass ratio of the deionized water to the deionized water is 5-10;

(2) The washed catalyst precursor feed liquid of the second step and the prepared ZnSO ₄ The solution is injected into a hastelloy mixing kettle in sequence, the temperature is controlled to be 25-35 ℃, and the solution is evenly mixed for 30-40 min;

and step four, carrying out secondary reduction reaction, including:

(1) Injecting materials: injecting the water-retaining film solution obtained in the third step into a high-pressure reaction kettle, and fully stirring and reacting for 4-6 h at normal temperature;

(2) Standing: stopping stirring, and standing for 2-4 h at normal temperature;

(3) And (3) secondary reduction: introducing nitrogen into the high-pressure reaction kettle for gas replacement; introducing high-purity hydrogen after replacement, heating and stirring after the hydrogen pressure reaches 6-8 MPa, stabilizing the pressure at 6-8 MPa in the reaction process, and performing timed reduction reaction after the temperature reaches 160-180 ℃ for 4-6 h;

(4) Cooling and reducing pressure: after the reduction is finished, gradually reducing the temperature and the pressure, slowly releasing the pressure to normal pressure when the temperature is reduced to below 60 ℃, and continuously reducing the temperature;

the fifth step, washing, includes: and (3) putting the Ru-Zn alloy microcrystal catalyst liquid after the reduction into a washing tank, and washing the catalyst liquid by using deionized water until the slurry is free of chloride ions and the pH value is 7-7.5, thus obtaining the Ru-Zn alloy microcrystal catalyst.

In one embodiment, in the preparation method, the alkaline solution in the first step is NaOH, and the mass fraction of the alkaline solution is 5-40%; combination of ZnThe salt solution is ZnSO ₄ And ZnCl ₂ One or two of the components are 5 to 50 percent by mass; the solution of Ru compound salt is RuCl ₃ The mass fraction is 10-40%.

In one embodiment, the above preparation method, ruCl, in the first step ₃ And deionized water in a mass ratio of 2-5.

In the production process of the catalyst, the Ru-Zn alloy microcrystalline catalyst with different specific surface areas, different pore volumes, different particle sizes and different activity indexes can be produced by changing different mass fractions and volume ratios of reaction raw materials and different parameters such as temperature, pressure and the like in the production process of the catalyst.

Evaluation of main technical indexes of catalyst

A. The main technical indexes of the catalyst comprise catalyst activity (benzene conversion rate) and cyclohexene selectivity, and the comprehensive indexes are expressed by activity indexes. The benzene selective hydrogenation reaction is carried out in a GS-1 type hastelloy high-pressure reaction kettle. 1.96 g of the Ru-Zn alloy microcrystalline catalyst prepared by the invention and 45.7 g of zinc sulfate heptahydrate (ZnSO) ₄ .7H ₂ 0) Then 280 mL of water are added, in H ₂ Heating to 135-140 ℃ under the conditions of pressure of 5.0MPa and stirring rate of 700-800 r/min, starting timing, operating the high-pressure kettle for 22 hours at constant temperature, adding 140 mL of benzene after heating to 150 ℃, adjusting the hydrogen pressure to 5.0MPa, increasing the stirring rate to 1400 r/min, starting timing, and sampling every 5 minutes. Detecting the product composition by gas chromatograph, detecting with hydrogen Flame Ionization Detector (FID), calculating the mass fraction of cyclohexane, cyclohexene and benzene by area normalization method, and calculating the benzene conversion rate C at different times according to the mass percentage of each detected component _BZ Cyclohexene Selective S _HE And an activity index γ. The calculation formula of each technical parameter is as follows:

………………………………（1）

in the formula:

C _BZ -benzene conversion,%

w ₁ -mass fraction of benzene in the raw material,%;

w ₂ -mass fraction of benzene in the reaction product,%.

………………………………（2）

In the formula:

S _HE -cyclohexene selectivity,%;

W _HE -cyclohexene mass fraction,%, in the product;

C _BZ -benzene conversion,%.

………………………………………（3）

In the formula:

γ _X -benzene mole conversion X% Activity index, representing grams of benzene converted per gram of catalyst per hour, subscript _X Representing the conversion of benzene, e.g.γ ₄₀ 、γ ₅₀ Respectively representing activity indexes when the conversion rate of benzene is 40% and 50%;

V _BZ benzene injection volume in (mL),V _BZ =140；

ρ _BZ -benzene Density in (g/cm) ³ ），ρ _BZ =0.88；

C _BZ -benzene conversion,%;

t _x -in benzene conversionA rate ofC _BZ The reaction time required,/% is, in h (h), subscript _X Represents the benzene conversion;

m _cat -the mass of the catalyst in (g),m _cat =1.96。

B. the specific surface area and the pore volume of the catalyst adopt N ₂ And (5) measuring by using an adsorption instrument. A sample of about 0.2 g of catalyst was weighed out at 150 deg.C ^o Degassing for 1.5 h at C, adsorbing and desorbing at liquid nitrogen temperature (77K) with nitrogen as adsorbate, and measuring N ₂ Adsorption and desorption isotherms. Then according to the BET equation

To do so by

To pairp/p ₀ Plotting, from the intercept and slope of the lineV _m . Then will beV _m Substitution equation

In (2), the specific surface area of the sample can be obtained.

Wherein the formula comprises:

S _g is the total specific surface area per gram of catalyst and is expressed in m ² ·g ^-1 ；

V _m The volume of adsorbate when a monolayer is fully paved on the solid surface;

V _mol is the molar volume of adsorbate in the standard state;

Lis the Avogadro constant;

a _m is the cross-sectional area of one nitrogen molecule.

The specific surface area and pore volume measurement results of the catalyst sample can be calculated by a data workstation of the nitrogen adsorption instrument.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Example 1

The preparation method of the catalyst comprises the following steps:

in a first step, a Ru-Zn alloy microcrystalline catalyst precursor is formulated and processed, comprising:

(1) In the batching tank, firstly deionized water with the temperature of 40 ℃ is injected, and then the prepared NaOH solution (5 percent) and ZnSO are injected in sequence ₄ Solution (10%) and RuCl ₃ (5%) the volume ratio of the solution, the salt solution and the alkali liquor is 1.

(2) And injecting the mixed solution into a Hastelloy stirring kettle, and fully stirring for 30min.

(3) After stirring uniformly, standing for 10min.

And a second step, a reduction reaction, comprising:

(1) Pretreatment: injecting the prepared Ru-Zn alloy microcrystal catalyst precursor into a high-pressure reaction kettle, controlling the reaction temperature at 40-45 ℃, and stirring for reaction for 8 hours.

(2) Standing for the first time: stopping stirring, cooling and adjusting, controlling the temperature at 25-30 ℃, and then standing for 8h.

(3) Primary reduction: firstly, introducing nitrogen into a high-pressure reaction kettle after standing for gas replacement, introducing high-purity hydrogen after replacement, heating and stirring after the hydrogen pressure reaches 8MPa, stabilizing the pressure at 8-8.5 MPa in the reaction process, and performing timed reduction reaction after the temperature reaches 80 ℃ for 8 hours.

(4) And (3) secondary standing: after the reaction is finished, reducing the temperature and the pressure, controlling the temperature to be 30-35 ℃, controlling the pressure to be 5MPa, and standing for 10 hours.

(5) Material returning and washing: and washing the catalyst liquid with deionized water, wherein the pH value is 7.5, and obtaining the primary reduction Ru-Zn alloy microcrystal catalyst precursor.

Thirdly, preparing a water retention membrane, which comprises the following steps:

(1) Configuration of ZnSO ₄ Solution: preparing ZnSO with deionized water ₄ Solution of ZnSO ₄ The mass ratio of the deionized water to the deionized water is 1.

(2) The washed catalyst precursor feed liquid of the second step and the prepared ZnSO ₄ The solution is injected into a hastelloy stirring kettle in sequence, the temperature is controlled to be 30-35 ℃, and the solution is uniformly stirred for 30min.

And step four, carrying out secondary reduction reaction, including:

(1) Injecting materials: and (4) injecting the water-retained membrane solution obtained in the third step into a high-pressure reaction kettle, and fully stirring and reacting for 4 hours at normal temperature.

(2) Standing: stopping stirring, and standing for 2h at normal temperature.

(3) And (3) secondary reduction: and (2) introducing nitrogen into the high-pressure reaction kettle after standing for gas replacement, introducing high-purity hydrogen after replacement, heating and stirring after the hydrogen pressure reaches 7MPa, stabilizing the pressure at 7-7.5 MPa in the reaction process, and performing timed reduction reaction after the temperature reaches 170 ℃ for 5 hours.

(4) Cooling and reducing pressure: after the reduction is finished, gradually reducing the temperature and the pressure, slowly releasing the pressure to normal pressure when the temperature is reduced to below 60 ℃, and continuously reducing the temperature.

The fifth step, washing, includes: and (3) putting the Ru-Zn alloy microcrystalline catalyst liquid after the reduction into a washing tank, and washing the catalyst liquid by using deionized water until the slurry is free of chloride ions and has a pH value of 7 to obtain the Ru-Zn alloy microcrystalline catalyst.

Fig. 1 is an XRD pattern of the bimetal alloy microcrystalline catalyst prepared in this example, which is calculated by Scherrer's formula to be 3.36nm in average crystallite diameter, and fig. 2 is a TEM photograph of the bimetal alloy microcrystalline catalyst prepared in this example, from which it can be seen that the Ru-Zn alloy microcrystalline catalyst has a crystallite diameter of 2nm to 7nm.

According to the catalyst evaluation method, the main technical indexes such as the activity index, the selectivity and the like of the catalyst obtained in example 1 are as follows:

t ₄₀ =12min，γ ₄₀ =126，S ₄₀ =87%；

t ₅₀ =16min，γ ₅₀ =118，S ₅₀ =85%；

t ₆₀ =20min，γ ₆₀ =113，S ₆₀ =83%；

t ₇₀ =24min，γ ₇₀ =110，S ₇₀ =81%

by low temperature N ₂ The catalyst obtained in example 1 was tested by the adsorbent method, and the results of testing the specific surface area and pore volume of the catalyst were as follows:

TABLE 1

Technical index	Specific surface area (m) of catalyst ² /g)	Pore volume (cm) of catalyst ³ /g)
			The result of the detection	57.4867	0.1739

Example 2

The preparation method of the catalyst comprises the following steps:

(1) In the batching tank, firstly deionized water with the temperature of 45 ℃ is injected, and then the prepared NaOH solution (6 percent) and ZnSO are injected in sequence ₄ Solution (10%) and RuCl ₃ (10%) the volume ratio of the solution, the salt solution and the alkali liquor is 1.

(3) After stirring uniformly, standing for 15min.

And a second step, a reduction reaction, comprising:

(1) Pretreatment: injecting the prepared Ru-Zn alloy microcrystal catalyst precursor into a high-pressure reaction kettle, controlling the reaction temperature at 45-50 ℃, and stirring for reaction for 9 hours.

(2) Standing for the first time: stopping stirring, cooling and adjusting, controlling the temperature at 25-30 ℃, and then standing for 9h.

(3) Primary reduction: firstly, introducing nitrogen into a high-pressure reaction kettle after standing for gas replacement, introducing high-purity hydrogen after replacement, heating and stirring after the hydrogen pressure reaches 8.5MPa, stabilizing the pressure at 8.5-9.0 MPa in the reaction process, and performing timing reduction reaction after the temperature reaches 90 ℃ for 8 hours.

(4) And (3) secondary standing: after the reaction is finished, reducing the temperature and the pressure, controlling the temperature to be 25-30 ℃ and the pressure to be 5.5 MPa, and standing for 12h.

(5) Material returning and washing: and washing the catalyst liquid with deionized water, wherein the pH value is 7, and obtaining the Ru-Zn alloy microcrystal catalyst precursor subjected to primary reduction.

(2) The washed catalyst precursor feed liquid of the second step and the prepared ZnSO ₄ The solution is injected into a hastelloy stirring kettle in sequence, the temperature is controlled to be 25-30 ℃, and the solution is uniformly stirred for 35min.

And step four, carrying out secondary reduction reaction, including:

(1) Injecting materials: and (4) injecting the water-retaining film solution obtained in the third step into a high-pressure reaction kettle, and fully stirring and reacting for 6 hours at normal temperature.

(2) Standing: stopping stirring, and standing for 4h at normal temperature.

(3) And (3) secondary reduction: and introducing nitrogen into the high-pressure reaction kettle after standing for gas replacement. Introducing high-purity hydrogen after replacement, heating and stirring after the hydrogen pressure reaches 7MPa, stabilizing the pressure at 7-8 MPa in the reaction process, and performing timing reduction reaction after the temperature reaches 165 ℃ for 5 hours.

The fifth step, washing

And (3) putting the Ru-Zn alloy microcrystalline catalyst liquid after the reduction into a washing tank, and washing the catalyst liquid by using deionized water until the slurry has no chloride ions and the pH value is 7 to obtain the Ru-Zn alloy microcrystalline catalyst.

Fig. 3 is an XRD pattern of the bimetal alloy microcrystalline catalyst prepared in this example, and the average crystallite diameter of the catalyst calculated by Scherrer's formula is 2.91nm, and fig. 4 is a TEM photograph of the bimetal alloy microcrystalline catalyst prepared in this example, from which it can be seen that the Ru-Zn alloy microcrystalline catalyst has a particle diameter of 2nm to 6nm.

Evaluation of main technical indexes of catalyst

According to the catalyst evaluation method described above, the main specifications of the catalyst obtained in example 2 were as follows:

t ₄₀ =11min，γ ₄₀ =137，S ₄₀ =86%；

t ₅₀ =14min，γ ₅₀ =135，S ₅₀ =85%；

t ₆₀ =19min，γ ₆₀ =119，S ₆₀ =83%；

t ₇₀ =24min，γ ₇₀ =110，S ₇₀ =80%

by low temperature N ₂ The adsorbent is used for detecting the catalyst obtained in example 2, and the detection results of the specific surface area and the pore volume of the obtained catalyst are as follows:

TABLE 2

Technical index	Catalyst specific surface area BET (m) ² /g)	Pore volume (cm) of catalyst ³ /g)
			The result of the detection	62.9301	0.2133

Example 3

The preparation method of the catalyst comprises the following steps:

the first step, ru-Zn alloy microcrystal catalyst precursor preparation and treatment, includes:

(1) In a proportioning tank, firstly injecting 40 ℃ deionized water, and then sequentially injecting the prepared NaOH solution (10 percent) and ZnSO ₄ Solution (8%) and RuCl ₃ (10%) the volume ratio of the solution, the salt solution and the alkali liquor is 1.

(2) And (3) injecting the mixed solution into a Hastelloy stirring kettle, and fully stirring for 40min.

(3) After stirring uniformly, standing for 20min.

And a second step, a reduction reaction, comprising:

(1) Pretreatment: injecting the prepared Ru-Zn alloy microcrystal catalyst precursor into a high-pressure reaction kettle, controlling the reaction temperature at 45-50 ℃, and stirring for reaction for 10 hours.

(3) Primary reduction: firstly, introducing nitrogen into a high-pressure reaction kettle after standing for gas replacement, introducing high-purity hydrogen after replacement, heating and stirring after the hydrogen pressure reaches 8.5MPa, stabilizing the pressure at 8-9 MPa in the reaction process, and performing timing reduction reaction after the temperature reaches 95 ℃, wherein the time is controlled to be 8 hours.

(4) And (3) secondary standing: after the reaction is finished, reducing the temperature and the pressure, controlling the temperature to be 25-30 ℃ and the pressure to be 5-6 MPa, and standing for 10h.

(5) Material returning and washing: and washing the catalyst solution with deionized water, wherein the pH value is 7.5, and obtaining the Ru-Zn alloy microcrystal catalyst precursor subjected to primary reduction.

(1) Arrangement of ZnSO ₄ Solution: preparing ZnSO with deionized water ₄ Solution of ZnSO ₄ The mass ratio of the deionized water to the deionized water is 1.

(2) The washed catalyst precursor feed liquid of the second step and the prepared ZnSO ₄ The solution is injected into a hastelloy stirring kettle in sequence, the temperature is controlled to be 25-30 ℃, and the solution is uniformly stirred for 30min.

And step four, carrying out secondary reduction reaction, including:

(1) Injecting materials: and (4) injecting the water-retaining film solution obtained in the third step into a high-pressure reaction kettle, and fully stirring and reacting for 4 hours at normal temperature.

(2) Standing: stopping stirring, and standing for 2h at normal temperature.

(3) And (3) secondary reduction: and (2) introducing nitrogen into the high-pressure reaction kettle after standing for gas replacement, introducing high-purity hydrogen after replacement, heating and stirring after the hydrogen pressure reaches 6.5MPa, stabilizing the pressure at 6-7 MPa in the reaction process, and performing timed reduction reaction after the temperature reaches 160 ℃, wherein the time is controlled to be 4 hours.

The fifth step, washing

And (3) putting the Ru-Zn alloy microcrystalline catalyst liquid after the reduction into a washing tank, and washing the catalyst liquid by using deionized water until the slurry is free of chloride ions and has a pH value of 7 to obtain the Ru-Zn alloy microcrystalline catalyst.

Fig. 5 is an XRD pattern of the bimetal alloy microcrystalline catalyst prepared in this example, and the average crystallite diameter of the catalyst calculated by Scherrer's formula is 2.85nm, and fig. 6 is a TEM photograph of the bimetal alloy microcrystalline catalyst prepared in this example, from which it can be seen that the Ru-Zn alloy microcrystalline catalyst has a particle diameter of 2nm to 5nm.

Evaluation of main technical indexes of catalyst

According to the catalyst evaluation method described above, the catalyst obtained in example 3 has the following main technical index results:

t ₄₀ =10min，γ ₄₀ =151，S ₄₀ =87%；

t ₅₀ =14min，γ ₅₀ =135，S ₅₀ =85%；

t ₆₀ =18min，γ ₆₀ =126，S ₆₀ =83%；

t ₇₀ =23min，γ ₇₀ =115，S ₇₀ =81%

by low temperature N ₂ The adsorbent is used for detecting the catalyst obtained in example 3, and the detection results of the specific surface area and the pore volume of the obtained catalyst are as follows:

TABLE 3

Technical index	Catalyst specific surface area BET (m) ² /g)	Pore volume (cm) of catalyst ³ /g)
			The result of the detection	64.6726	0.1949

Example 4

The preparation method of the catalyst comprises the following steps:

(1) In the batching tank, firstly 50 ℃ deionized water is injected, and then the prepared NaOH solution (10 percent) and ZnSO are injected in sequence ₄ Solution (10%) and RuCl ₃ (12%) the volume ratio of the solution, the salt solution and the alkali liquor is 1.

(3) After stirring uniformly, standing for 20min.

And a second step of primary reduction reaction, which comprises the following steps:

(1) Pretreatment: injecting the prepared Ru-Zn alloy microcrystal catalyst precursor into a high-pressure reaction kettle, controlling the reaction temperature at 50 ℃, and stirring for reaction for 10 hours.

(3) Primary reduction: firstly, introducing nitrogen into a high-pressure reaction kettle after standing for gas replacement, introducing high-purity hydrogen after replacement, heating and stirring after the hydrogen pressure reaches 8.5MPa, stabilizing the pressure at 8-9 MPa in the reaction process, and performing timed reduction reaction after the temperature reaches 100 ℃ for 8 hours.

(4) And (3) secondary standing: after the reaction is finished, reducing the temperature and the pressure, controlling the temperature to be 25-30 ℃ and the pressure to be 5-6 MPa, and standing for 12h.

(5) Material returning and washing: and washing the catalyst solution with deionized water, wherein the pH value is 7.5, and obtaining the precursor of the primary reduction Ru-Zn alloy microcrystal catalyst.

And step three, preparing a water retention film, which comprises the following steps:

(1) Configuration ofZnSO ₄ Solution: preparing ZnSO with deionized water ₄ Solution of ZnSO ₄ The mass ratio of the deionized water to the deionized water is 1.

And step four, carrying out secondary reduction reaction, including:

(1) Injecting materials: and (4) injecting the water-retained membrane solution obtained in the third step into a high-pressure reaction kettle, and fully stirring and reacting for 5 hours at normal temperature.

(2) Standing: stopping stirring, and standing for 3h at normal temperature.

(3) And (3) secondary reduction: and introducing nitrogen into the high-pressure reaction kettle after standing to perform gas replacement. Introducing high-purity hydrogen after replacement, heating and stirring after the hydrogen pressure reaches 6.5MPa, stabilizing the pressure at 6.5-7.5 MPa in the reaction process, and performing timing reduction reaction after the temperature reaches 165 ℃ for 5 hours.

Fig. 7 is an XRD pattern of the bimetal alloy microcrystalline catalyst prepared in this example, which is calculated by Scherrer's formula to be 2.55nm in average crystallite diameter, and fig. 8 is a TEM photograph of the bimetal alloy microcrystalline catalyst prepared in this example, from which it can be seen that the Ru-Zn alloy microcrystalline catalyst has a crystallite diameter of 2nm to 5nm.

Evaluation of main technical indexes of catalyst

The method for evaluating the main indexes of the catalyst obtained in example 4 is as described above, and the results of the main technical indexes of the catalyst are as follows:

t ₄₀ =9.2min， γ ₄₀ =164，S ₄₀ =88%；

t ₅₀ =12.2min，γ ₅₀ =155，S ₅₀ =86%；

t ₆₀ =17min， γ ₆₀ =133，S ₆₀ =84%；

t ₇₀ =21min， γ ₇₀ =126，S ₇₀ =82%

by low temperature N ₂ The adsorbent is used for detecting the catalyst obtained in example 4, and the detection results of the specific surface area and the pore volume of the obtained catalyst are as follows:

TABLE 4

Technical index	Catalyst specific surface area BET (m) ² /g)	Pore volume (cm) of catalyst ³ /g)
			The result of the detection	76.7665	0.2942

Example 5

The preparation method of the catalyst comprises the following steps:

(1) In a proportioning tank, firstly injecting 40 ℃ deionized water, and then sequentially injecting the prepared NaOH solution (7 percent) and ZnSO ₄ Solution (9%) and RuCl ₃ (10%) solution, saline solution andand standing for 10min under the condition that the volume ratio of the alkali liquor is 1.

(3) After stirring uniformly, standing for 20min.

And a second step, a reduction reaction, comprising:

(1) Pretreatment: injecting the prepared Ru-Zn alloy microcrystal catalyst precursor into a high-pressure reaction kettle, controlling the reaction temperature at 45 ℃, and stirring for reaction for 10 hours.

(2) Standing for the first time: stopping stirring, cooling and adjusting, controlling the temperature at 25-30 ℃, and then standing for 6h.

(3) Primary reduction: firstly, introducing nitrogen into a high-pressure reaction kettle after standing for gas replacement, introducing high-purity hydrogen after replacement, heating and stirring after the hydrogen pressure reaches 8.0MPa, stabilizing the pressure at 8-9 MPa in the reaction process, and performing timed reduction reaction after the temperature reaches 95 ℃ for 8 hours.

Step three, preparing a water retention film, comprising the following steps:

And step four, carrying out secondary reduction reaction, including:

(2) Standing: stopping stirring, and standing for 3h at normal temperature.

(3) And (3) secondary reduction: and introducing nitrogen into the high-pressure reaction kettle after standing to perform gas replacement. Introducing high-purity hydrogen after replacement, heating and stirring after the hydrogen pressure reaches 6.5MPa, stabilizing the pressure at 6.5-7.5 MPa in the reaction process, and performing timing reduction reaction after the temperature reaches 160 ℃, wherein the time is controlled to be 4 hours.

The fifth step, washing, namely: and (3) putting the Ru-Zn alloy microcrystalline catalyst liquid after the reduction into a washing tank, and washing the catalyst liquid by using deionized water until the slurry has no chloride ions and the pH value is 7 to obtain the Ru-Zn alloy microcrystalline catalyst.

Fig. 9 is an XRD pattern of the bimetal alloy microcrystalline catalyst prepared in this example, and the average crystallite diameter of the catalyst calculated by Scherrer's formula is 3.55nm, and fig. 10 is a TEM photograph of the bimetal alloy microcrystalline catalyst prepared in this example, from which it can be seen that the Ru-Zn alloy microcrystalline catalyst has a particle diameter of 2nm to 8 nm.

Evaluation of main technical indexes of catalyst

The evaluation method of the main indexes of the catalyst obtained in example 5 is as described above, and the main technical indexes of the catalyst have the following results:

t ₄₀ =13min，γ ₄₀ =116，S ₄₀ =84%；

t ₅₀ =17min，γ ₅₀ =110，S ₅₀ =82%；

t ₆₀ =21min，γ ₆₀ =108，S ₆₀ =80%；

t ₇₀ =25min，γ ₇₀ =106，S ₇₀ =76%

by low temperature N ₂ The catalyst obtained in example 5 was tested with an adsorbent to obtain the results of testing the specific surface area and pore volume of the catalyst as shown inThe following:

TABLE 5

Technical index	Catalyst specific surface area BET (m) ² /g)	Pore volume (cm) of catalyst ³ /g)
			The result of the detection	53.1716	0.1372

Example 6

The preparation method of the catalyst comprises the following steps:

(1) In the batching tank, firstly deionized water with the temperature of 45 ℃ is injected, and then the prepared NaOH solution (8 percent) and ZnSO are sequentially injected ₄ Solution (8%) and RuCl ₃ (12%) the volume ratio of the solution, the salt solution and the alkali liquor is 1.

(2) And injecting the mixed solution into a Hastelloy stirring kettle, and fully stirring for 35min.

(3) After stirring uniformly, standing for 15min.

(1) Pretreatment: injecting the prepared Ru-Zn alloy microcrystal catalyst precursor into a high-pressure reaction kettle, controlling the reaction temperature at 50 ℃, and stirring for reaction for 8 hours.

(3) Primary reduction: firstly, introducing nitrogen into a high-pressure reaction kettle after standing for gas replacement, introducing high-purity hydrogen after replacement, heating and stirring after the hydrogen pressure reaches 8.0MPa, stabilizing the pressure at 8-9 MPa in the reaction process, and performing timed reduction reaction after the temperature reaches 90 ℃ for 8 hours.

Step three, preparing a water retention film, comprising the following steps:

(2) The washed catalyst precursor feed liquid of the second step and the prepared ZnSO ₄ The solution is injected into a hastelloy stirring kettle in sequence, the temperature is controlled to be 25-30 ℃, and the solution is uniformly stirred for 25min.

And step four, carrying out secondary reduction reaction, including:

(2) Standing: stopping stirring, and standing for 3h at normal temperature.

(3) And (3) secondary reduction: and introducing nitrogen into the high-pressure reaction kettle after standing for gas replacement. Introducing high-purity hydrogen after replacement, heating and stirring after the hydrogen pressure reaches 6.5MPa, stabilizing the pressure at 6.5-7.5 MPa in the reaction process, and performing timing reduction reaction after the temperature reaches 170 ℃ for 6 hours.

Fig. 11 is an XRD pattern of the bimetal alloy microcrystalline catalyst prepared in this example, which has an average crystallite diameter of 3.51nm calculated by Scherrer's formula, and fig. 12 is a TEM photograph of the bimetal alloy microcrystalline catalyst prepared in this example, from which it can be seen that the Ru-Zn alloy microcrystalline catalyst has a particle diameter of 2nm to 7nm.

Evaluation of main technical indexes of catalyst

The method for evaluating the main indexes of the catalyst obtained in example 6 is as described above, and the results of the main technical indexes of the catalyst are as follows:

t ₄₀ =12min，γ ₄₀ =126，S ₄₀ =85%；

t ₅₀ =15min，γ ₅₀ =126，S ₅₀ =82%；

t ₆₀ =18min，γ ₆₀ =126，S ₆₀ =80%；

t ₇₀ =23min，γ ₇₀ =115，S ₇₀ =77%

by low temperature N ₂ The adsorbent is used for detecting the catalyst obtained in example 6, and the detection results of the specific surface area and the pore volume of the obtained catalyst are as follows:

TABLE 6

Technical index	Catalyst specific surface area BET (m) ² /g)	Pore volume (cm) of catalyst ³ /g)
			The result of the detection	58.3656	0.1748

Example 7

The preparation method of the catalyst comprises the following steps:

(1) In the batching tank, firstly deionized water with the temperature of 40 ℃ is injected, and then the prepared NaOH solution (6 percent) and ZnSO are injected in sequence ₄ Solution (8%) and RuCl ₃ (10%) the volume ratio of the solution, the salt solution and the alkali liquor is 1.

(3) After stirring uniformly, standing for 15min.

And a second step, a reduction reaction, comprising:

(1) Pretreatment: injecting the prepared Ru-Zn alloy microcrystal catalyst precursor into a high-pressure reaction kettle, controlling the reaction temperature at 40 ℃, and stirring for reaction for 9 hours.

(3) Primary reduction: firstly, introducing nitrogen into a high-pressure reaction kettle after standing for gas replacement, introducing high-purity hydrogen after replacement, heating and stirring after the hydrogen pressure reaches 8.5MPa, stabilizing the pressure at 8-9 MPa in the reaction process, and performing timed reduction reaction after the temperature reaches 95 ℃ for 8 hours.

(4) And (3) secondary standing: after the reaction is finished, reducing the temperature and the pressure, controlling the temperature to be 25-30 ℃ and the pressure to be 5-6 MPa, and standing for 10 hours.

And step four, carrying out secondary reduction reaction, including:

(2) Standing: stopping stirring, and standing for 2h at normal temperature.

(3) And (3) secondary reduction: and introducing nitrogen into the high-pressure reaction kettle after standing to perform gas replacement. Introducing high-purity hydrogen after replacement, heating and stirring after the hydrogen pressure reaches 6.5MPa, stabilizing the pressure at 6.5-7.5 MPa in the reaction process, and performing timed reduction reaction after the temperature reaches 170 ℃ for 6 hours.

Fig. 13 is an XRD pattern of the bimetal alloy microcrystalline catalyst prepared in this example, which is calculated by Scherrer's formula to be 3.75nm in average crystallite diameter, and fig. 14 is a TEM photograph of the bimetal alloy microcrystalline catalyst prepared in this example, from which it can be seen that the Ru-Zn alloy microcrystalline catalyst has a crystallite diameter of 2nm to 8 nm.

Evaluation of main technical indexes of catalyst

The evaluation method of the main indexes of the catalyst obtained in example 7 is as described above, and the main technical indexes of the catalyst have the following results:

t ₄₀ =15min，γ ₄₀ =101，S ₄₀ =88%；

t ₅₀ =17min，γ ₅₀ =111，S ₅₀ =86%；

t ₆₀ =20min，γ ₆₀ =113，S ₆₀ =84%；

t ₇₀ =24min，γ ₇₀ =110，S ₇₀ =82%

by low temperature N ₂ The adsorbent is used for detecting the catalyst obtained in example 7, and the detection results of the specific surface area and the pore volume of the obtained catalyst are as follows:

TABLE 7

Technical index	Catalyst specific surface area BET (m) ² /g)	Pore volume (cm) of catalyst ³ /g)
			The result of the detection	51.4662	0.1343

Example 8

The preparation of the catalysts was carried out according to examples 1 to 7, giving catalysts having the following specific surface areas, pore volumes and activity indices:

TABLE 8

	Specific surface area (m) ² /g)	Pore volume (cm) ³ /g)	Index of activityγ ₄₀	Index of activityγ ₅₀
					Catalyst 1	57.4867	0.1739	126	118
Catalyst 2	62.9301	0.2133	137	135
					Catalyst 3	64.6726	0.1949	151	135
Catalyst 4	76.7665	0.2942	164	155
					Catalyst 5	53.1716	0.1372	116	110
Catalyst 6	58.3656	0.1748	126	126
					Catalyst 7	51.4662	0.1343	101	111

Example 9

And (3) omitting the steps of secondary standing and cooling, returning and washing, preparation of a water retention film in the third step and material injection and standing in the fourth step according to the proportion and conditions of the embodiments 5-7, reducing according to the primary reduction condition without returning, and continuously reducing the pressure and heating according to the secondary reduction condition to prepare 8-10 of the obtained catalyst.

With reference to the formulation and conditions of example 5, the preparation of catalyst 8 comprises the following steps:

(1) In the batching tank, firstly deionized water with the temperature of 40 ℃ is injected, and then the prepared NaOH solution (7 percent) and ZnSO are injected in sequence ₄ Solution (9%) and RuCl ₃ (10%) the volume ratio of the solution, the salt solution and the alkali liquor is 1.

(3) After stirring uniformly, standing for 20min.

(1) Pretreatment: and injecting the prepared Ru-Zn alloy microcrystal catalyst precursor into a high-pressure reaction kettle, controlling the reaction temperature at 45 ℃, and stirring for reaction for 10 hours.

(2) Standing: stopping stirring, cooling and adjusting, controlling the temperature at 25-30 ℃, and then standing for 6h.

(3) Primary reduction: firstly, introducing nitrogen into a high-pressure reaction kettle after standing for gas replacement, introducing high-purity hydrogen after replacement, heating and stirring after the hydrogen pressure reaches 8.0MPa, stabilizing the pressure at 8-9 MPa in the reaction process, and performing timing reduction reaction after the temperature reaches 95 ℃, wherein the time is controlled to be 8 hours.

And step three, carrying out secondary reduction reaction, including:

(1) And (3) secondary reduction: after primary reduction, the pressure is gradually reduced, the hydrogen pressure reaches 6.5MPa, then heating and stirring are carried out, the pressure needs to be stabilized at 6.5-7.5 MPa in the reaction process, and when the temperature reaches 160 ℃, the timing reduction reaction is carried out, and the time is controlled to be 4 hours.

(2) Cooling and reducing pressure: after the reduction is finished, gradually reducing the temperature and the pressure, slowly releasing the pressure to normal pressure when the temperature is reduced to below 60 ℃, and continuously reducing the temperature.

The fourth step, washing, includes: and (3) putting the Ru-Zn alloy microcrystalline catalyst liquid after the reduction into a washing tank, and washing the catalyst liquid by using deionized water until the slurry has no chloride ions and the pH value is 7 to obtain the Ru-Zn alloy microcrystalline catalyst 8.

The second step of standing and cooling, material returning and washing, the third step of preparation of water-retaining films and the fourth step of material injection and standing are omitted according to the proportion and conditions of the embodiments 6 to 7, and the catalysts 9 to 10 are prepared.

And (3) detecting and evaluating the catalyst by 8-10 according to the method to obtain the following specific surface area, pore volume and activity index results:

TABLE 9

	Specific surface area (m) ² /g)	Pore volume (cm) ³ /g)	Index of activityγ ₄₀	Index of activityγ ₅₀
					Catalyst 8	41.7592	0.1045	73	85
Catalyst 9	43.9765	0.1096	79	88
					Catalyst 10	46.3548	0.1189	86	91

Example 10

The specific surface areas and activity indexes of catalysts 1 to 7 prepared in examples 1 to 7 and catalysts 8 to 10 prepared in example 9 were set toγ ₄₀ Plotting, and finding out the specific surface area and the activity index of the Ru-Zn catalyst microcrystalγ ₄₀ I.e. a specific surface area of 40m ² /g～60m ² Per g corresponding to the catalyst activity index (γ ₄₀ ) 60 to 130; specific surface area 60m ² /g～80m ² Per g corresponding to the catalyst activity index (γ ₄₀ ) 130 to 180 as shown in fig. 15. The dotted line in fig. 15 may indicate that the y value is in the range of ± 5%.

The catalyst prepared by the method is Ru-Zn alloy microcrystal which is in a crystalline alloy structure, and the catalyst particles are uniform as can be seen from an electron microscope image. A large number of experiments prove that the crystalline alloy has stable structure, low temperature sensitivity and difficult damage, and improves the activity index of the catalyst. The catalysts 1 to 7 prepared by the method of the invention are mixed, and the mixed catalyst is detected and evaluated according to the method, so that the data shown in the following table are obtained:

watch 10

Ru-Zn alloy microcrystalline catalyst 140 ^o Cyclohexene selectivity data at C

t/min	T/ ^o C	C _BZ mol%	S _HE mol%	Y _HE mol%
					10	139.9	44.54	84.82	37.78
15	141.7	61.30	81.46	49.94
					20	139.6	75.01	77.22	57.93
25	141.5	82.94	73.16	60.68
					30	140.3	88.78	69.13	61.37
45	140.1	96.54	56.62	54.66
					60	138.4	98.82	46.20	45.65

(pretreatment is carried out for 22h under the pressure of 5MPa and the temperature of the reaction kettle is 140 ℃ under the condition that the rotating speed of a stirrer is 1000 revolutions per minute ^o About C, the rotating speed of the stirrer is 1400 revolutions per minute.C _BZ Is the benzene conversion, S _HE Is cyclohexene selectivity, Y _HE Is the cyclohexene yield. )

For this mixed catalyst, the results for activity index and cyclohexene selectivity at 40% and 50% benzene conversion, respectively, are as follows:

t ₄₀ =12min，γ ₄₀ =126，S ₄₀ =85%；

t ₅₀ =14min，γ ₅₀ =135，S ₅₀ =83%。

the above description is intended to illustrate the preferred embodiments of the present invention, but the present invention is only illustrative and should not be construed as being limited to the scope of the present invention. All equivalent changes and modifications made within the scope of the present invention shall fall within the scope of the present invention.

Claims

1. A bimetal alloy microcrystal catalyst for preparing cyclohexene by hydrogenation is characterized by mainly comprising or consisting of Ru-Zn alloy microcrystal, wherein the Ru-Zn alloy microcrystal comprises 98-80% of Ru and 2-20% of Zn by mass, the average microcrystal particle size obtained by an XRD measurement method is 2nm-2.91nm, and the specific surface area is 60m ² /g～80m ² G, corresponding to the catalyst activity index γ ₄₀ 130-180, cyclohexene selectivity S when benzene conversion is 40% ₄₀ 84 to 88 percent of the total weight of the composition,

the catalyst for preparing the bimetal cyclohexene alloy microcrystal by hydrogenation is prepared byThe preparation method comprises the following steps: stirring and standing the alkali liquor and the salt liquor in a stirring kettle, and injecting the mixture into a high-pressure kettle for primary reduction, wherein the primary reduction is a timed reduction reaction after the hydrogen pressure is stabilized at 8 MPa-10 MPa and the temperature reaches 80-100 ℃, and the time is controlled at 6-8 h to obtain a primary reduced Ru-Zn alloy microcrystal precursor; then, preparing a water retention film, which comprises the following steps: preparing ZnSO with deionized water ₄ Solution, washing the catalyst precursor feed liquid and preparing ZnSO ₄ Sequentially injecting the solution into a Hastelloy stirring kettle and stirring; then carrying out secondary reduction, wherein the secondary reduction is to carry out timing reduction reaction after the hydrogen pressure is stabilized at 6-8 MPa and the temperature reaches 160-180 ℃, controlling the time to be 4-6 h, and washing to obtain the Ru-Zn alloy microcrystal.

2. The catalyst of claim 1, wherein the hydrogenation to cyclohexene bimetallic alloy microcrystalline catalyst does not comprise a support.

3. Catalyst according to claim 1, characterized in that the pore volume of the Ru-Zn alloy crystallites is 0.10 cm ³ /g～0.35 cm ³ /g。

4. Catalyst according to claim 1, characterized in that the pore volume of the Ru-Zn alloy crystallites is 0.13 cm ³ /g～0.29 cm ³ /g。

5. The catalyst according to claim 1, characterized in that the Ru-Zn alloy crystallites have a particle size in the range of 2nm to 7nm as measured by TEM.

6. The catalyst according to claim 1, characterized in that the Ru-Zn alloy crystallites have a particle size in the range of 2nm to 6nm as measured according to TEM.

7. The catalyst according to claim 1, wherein the bi-metal cyclohexene alloy hydrogenating catalyst crystallite contains unavoidable impurities.