Ethylene oxychlorination catalyst, preparation method and application
阅读说明：本技术 一种乙烯氧氯化催化剂及制备方法和应用 (Ethylene oxychlorination catalyst, preparation method and application ) 是由 于海彬 吕艳红 王占友 易光铨 孙康 黎源 华卫琦 于 2021-09-09 设计创作，主要内容包括：本发明提供一种乙烯氧氯化催化剂及制备方法和应用,该催化剂载体为Al-(2)O-(3)-Nb-(2)O-(5)微球,活性组分包含铜元素、镁元素和碱金属元素。该催化剂制备方法步骤包括：将铝源、水与胶溶剂混合,搅拌得到溶胶A；将铜盐、铌盐与水混合,得到溶液B,然后将溶液B加入到溶胶A中,搅拌得到浆料C；浆料C进行干燥、焙烧、筛分,得到含有铜元素的Al-(2)O-(3)-Nb-(2)O-(5)微球；将碱金属盐、镁盐与盐酸混合,得到溶液D,然后将含有铜元素的Al-(2)O-(3)-Nb-(2)O-(5)微球加入到溶液D中室温浸渍,取出干燥,得到乙烯氧氯化催化剂。该催化剂用于乙烯氧氯化反应中具有优异的活性、选择性及耐磨性能,适合工业化生产及应用。(The invention provides an ethylene oxychlorination catalyst, a preparation method and application thereof, wherein the catalyst carrier is Al 2 O 3 ‑Nb 2 O 5 The active component of the microsphere comprises copper element, magnesium element and alkali metal element. The preparation method of the catalyst comprises the following steps: mixing an aluminum source, water and a peptizing agent, and stirring to obtain sol A; mixing copper salt, niobium salt and water to obtain a solution B, adding the solution B into the sol A, and stirring to obtain slurry C; drying, roasting and screening the slurry C to obtain Al containing copper element 2 O 3 ‑Nb 2 O 5 Microspheres; mixing alkali metal salt, magnesium salt and hydrochloric acid to obtain solution D, and adding Al containing copper element 2 O 3 ‑Nb 2 O 5 And adding the microspheres into the solution D for soaking at room temperature, taking out and drying to obtain the ethylene oxychlorination catalyst. The catalyst has excellent activity, selectivity and wear resistance when being used in the ethylene oxychlorination reaction, and is suitable for industrial production and application.)
1. The ethylene oxychlorination catalyst is characterized in that the catalyst carrier is Al2O3-Nb2O5The active component of the microsphere comprises copper element, magnesium element and alkali metal element.
2. The ethylene oxychlorination catalyst according to claim 1, wherein the metal element comprises, by mass, 3.5 to 6% of copper, 1 to 2.5% of magnesium, 0.2 to 0.75% of an alkali metal element, 0.1 to 0.55% of niobium, and 41 to 46% of aluminum, based on 100% of the total mass of the catalyst; preferably, the mass content of the metal elements is 4-5% of copper elements, 1.1-1.5% of magnesium elements, 0.3-0.5% of alkali metal elements, 0.2-0.4% of niobium elements and 42-45% of aluminum elements;
preferably, the ethylene oxychlorination catalyst does not contain rare earth metal elements;
preferably, the active components copper, magnesium and alkali metal in the ethylene oxychlorination catalyst are all present in the form of metal salts, preferably metal chlorides.
3. The ethylene oxychlorination catalyst according to claim 1 or 2, wherein the alkali metal element is potassium and/or cesium, preferably in a mass ratio of potassium to cesium of 1: (0 to 1), preferably 1: (0.05 to 0.3);
the carrier Al2O3-Nb2O5Microsphere diameter D10>20 μm, D50 of 50-80 μm, D90<200μm；
The ethylene oxychlorination catalyst has a specific surface area of 140-170 m2(ii)/g; the pore volume is 0.35-0.5 ml/g; the average pore diameter is 8-10 nm;
the abrasion index of the ethylene oxychlorination catalyst is less than or equal to 1%.
4. A process for the preparation of an ethylene oxychlorination catalyst according to any one of claims 1 to 3, comprising the steps of:
(1) mixing an aluminum source, water and a peptizing agent, and stirring to obtain sol A;
(2) mixing copper salt, niobium salt and water to obtain a solution B, adding the solution B into the sol A, and stirring to obtain slurry C;
(3) drying, roasting and screening the slurry C to obtain Al containing copper element2O3-Nb2O5Microspheres;
(4) mixing alkali metal salt, magnesium salt and hydrochloric acid to obtain solution D, and adding Al containing copper element2O3-Nb2O5And (4) adding the microspheres into the solution D for dipping, taking out and drying to obtain the ethylene oxychlorination catalyst.
5. The preparation method according to claim 4, wherein in the step (1), the aluminum source is any one or a combination of at least two of pseudo-boehmite, activated alumina powder, aluminum hydroxide powder and aluminum sol, preferably a mixture of pseudo-boehmite and aluminum hydroxide powder in any proportion, more preferably the mass ratio of pseudo-boehmite to aluminum hydroxide powder is (1-2): 1;
preferably, if the aluminum source contains impurity element sodium, the content of the element sodium is required to be less than 100ppm, and preferably less than 30 ppm;
the peptizing agent is a nitric acid aqueous solution, preferably a nitric acid aqueous solution with the mass fraction of 10-68%;
preferably, the mass ratio of the aluminum source (calculated as alumina) to the peptizing agent and the water is 1: (0.06-0.2): (1.1 to 3.2), preferably 1: (0.06-0.15): (1.5-2.5), wherein the water comprises moisture contained in an aluminum source.
6. The method according to claim 4 or 5, wherein in the step (2), the copper salt is any one of copper chloride dihydrate, copper nitrate and copper acetate or a combination of at least two of the above, preferably copper chloride dihydrate;
the niobium salt is any one or combination of at least two of niobium oxalate, ammonium niobium oxalate and niobic acid, and is preferably niobium oxalate;
the mass ratio of the copper salt (calculated by copper element) to the niobium salt (calculated by niobium element) is (5-50): 1, preferably (10 to 44): 1;
the mass ratio of the total mass of the copper salt and the niobium salt to the water is 1: (4-10), preferably 1: (5-8);
in the step (2), the solution B is slowly added into the sol A, preferably in a continuous feeding mode, and more preferably in a dropwise adding mode;
preferably, the feeding time of the solution B is 1-120 min, preferably 1-30 min;
in the step (2), the viscosity of the slurry C is 1000 to 8000 mPa.s, preferably 2000 to 5000 mPa.s.
7. The process according to any one of claims 4 to 6, wherein in step (3), the drying is in the form of oven drying, infrared drying, freeze drying or spray drying, preferably centrifugal spray drying;
preferably, the drying is carried out, wherein the air inlet temperature is 180-250 ℃, and the air outlet temperature is 90-120 ℃;
in the step (3), the roasting temperature is 300-700 ℃, and preferably 400-550 ℃; the roasting time is 2-10 h, preferably 2-5 h; the roasting atmosphere is air;
in the step (3), the Al containing copper element2O3-Nb2O5Microsphere D10>20 μm, D50 of 50-80 μm, D90<200μm。
8. The production method according to any one of claims 4 to 7, wherein in the step (4), the alkali metal salt is any one of or a combination of at least two of a hydrochloride, a carbonate, and a nitrate of an alkali metal, preferably any one of or a combination of at least two of a hydrochloride and a carbonate of potassium and cesium;
the magnesium salt is any one or combination of magnesium chloride and magnesium nitrate, preferably magnesium chloride;
preferably, the mass ratio of the alkali metal salt (calculated as alkali metal element) to the magnesium salt (calculated as magnesium element) is 1: (1 to 20), preferably 1: (3-16);
the mass ratio of the total mass of the alkali metal salt and the magnesium salt to the hydrochloric acid is 1: (4-10), preferably 1: (5-8);
in the step (4), the mass fraction of the hydrochloric acid is 5-15%, and the optimal selection is 8-12%;
in the step (4), the impregnation is carried out at room temperature, and the impregnation time is preferably 0.1-2 h;
in the step (4), the drying mode comprises the steps of airing the surface moisture at room temperature, and then drying in an oven to constant weight;
preferably, the airing time is 1-4 h;
preferably, the drying temperature is 60-150 ℃, and the drying time is 8-24 h.
9. Use of a catalyst according to any one of claims 1 to 3 or prepared by a process according to any one of claims 4 to 8 in a fluid bed process to catalyse the oxychlorination of ethylene to 1, 2-dichloroethane.
10. A process for the oxychlorination of ethylene to produce 1, 2-dichloroethane, characterized in that it is carried out in a fluidized-bed reactor using a catalyst as claimed in any one of claims 1 to 3 or a catalyst prepared by a process as claimed in any one of claims 4 to 8, the oxychlorination conditions comprising:
the volume ratio of the hydrogen chloride to the ethylene to the oxygen is 2: (1-1.1): (0.52-0.6) and a volume space velocity of 1400-2000 h-1；
The oxychlorination reaction is carried out at the temperature of 210-250 ℃ and under the pressure (absolute pressure) of 0.1-0.5 MPa.
Technical Field
The invention belongs to the field of catalysts, relates to an oxychlorination catalyst and a preparation method thereof, and also relates to application of the catalyst in an ethylene oxychlorination fluidized bed process.
Background
Polyvinyl chloride is one of five general resins and is polymerized from vinyl chloride monomer. At present, the mainstream production process of vinyl chloride internationally is to prepare dichloroethane by oxychlorination of ethylene and then crack the dichloroethane to obtain vinyl chloride. The key of the process is the development of a high-activity and high-selectivity ethylene oxychlorination catalyst.
The patent CN02103774.4 adopts a coprecipitation-impregnation method to prepare the catalyst, a large amount of acid liquor, alkali liquor and washing liquor are required to be consumed in the preparation process, the steps are complicated, the cost of three wastes is high, and the industrial production is not facilitated.
The patent CN200910235957.3 introduces an organic dispersant and an organic pore-forming agent to promote the dispersion of active components, improves the pore structure property of the catalyst, has higher cost and increases the explosion risk in the roasting process.
The patent CN201480011596.3 adopts a two-step impregnation method to prepare the supported copper catalyst, the process is simple, but the interaction force between copper chloride obtained by the impregnation method and an alumina carrier is weak, the copper chloride is easy to run off, so that the catalyst is sticky, and the stable operation of the device is influenced.
From the above patents, the existing ethylene oxychlorination catalyst has complex preparation process, high cost, easy loss of copper chloride, easy stickiness of the catalyst and poor stability. Therefore, it is important to develop a catalyst which is relatively simple in preparation process, highly active, and resistant to stickiness.
Disclosure of Invention
One of the objects of the present invention is: the catalyst is an aluminum oxide-niobium pentoxide microsphere containing copper, has better activity, stronger binding force between copper chloride and a carrier, better wear resistance and difficult copper loss.
Another object of the present invention is to: the formula and the preparation method of the ethylene oxychlorination catalyst are provided, and the preparation method has the characteristics of wide raw material source, simple process and good repeatability.
In order to achieve the above purpose, the invention adopts the following technical scheme:
the invention provides an ethylene oxychlorination catalyst, wherein the catalyst carrier is Al2O3-Nb2O5The active component of the microsphere comprises copper element, magnesium element and alkali metal element.
Preferably, the active components copper, magnesium and alkali metal in the ethylene oxychlorination catalyst are all present in the form of metal salts, preferably metal chlorides.
Preferably, the ethylene oxychlorination catalyst does not contain rare earth metal elements.
The ethylene oxychlorination catalyst comprises, by mass, 3.5-6% of metal elements, 1-2.5% of magnesium elements, 0.2-0.75% of alkali metal elements, 0.1-0.55% of niobium elements and 41-46% of aluminum elements, wherein the total mass is 100%;
preferably, the ethylene oxychlorination catalyst comprises, by mass, 4-5% of a metal element, 1.1-1.5% of a magnesium element, 0.3-0.5% of an alkali metal element, 0.2-0.4% of a niobium element and 42-45% of an aluminum element, based on 100% of the total mass of the ethylene oxychlorination catalyst.
In the ethylene oxychlorination catalyst, the alkali metal element is preferably potassium and/or cesium; more preferably, the mass ratio of potassium to cesium is 1: (0 to 1), preferably 1: (0.05-0.3).
The ethylene oxychlorination catalyst and the carrier Al of the invention2O3-Nb2O5Microsphere diameter D10>20 μm, D50 of 50-80 μm, D90<200μm；
The ethylene oxychlorination catalyst has a specific surface area of 140-170 m2(ii)/g; the pore volume is 0.35-0.5 ml/g; the average pore diameter is 8-10 nm;
the abrasion index of the ethylene oxychlorination catalyst is less than or equal to 1%.
The invention also provides a preparation method of the ethylene oxychlorination catalyst, which comprises the following steps:
(1) mixing an aluminum source, water and a peptizing agent, and stirring to obtain sol A;
(2) mixing copper salt, niobium salt and water to obtain a solution B, adding the solution B into the sol A, and stirring to obtain slurry C;
(3) drying, roasting and screening the slurry C to obtain Al containing copper element2O3-Nb2O5Microspheres;
(4) mixing alkali metal salt, magnesium salt and hydrochloric acid to obtain solution D, and adding Al containing copper element2O3-Nb2O5And (4) adding the microspheres into the solution D for dipping, taking out and drying to obtain the ethylene oxychlorination catalyst.
In the step (1), the aluminum source is any one or a combination of at least two of pseudo-boehmite, activated alumina powder, aluminum hydroxide powder and aluminum sol, preferably a mixture of the pseudo-boehmite and the aluminum hydroxide powder in any proportion, more preferably a mass ratio of the pseudo-boehmite to the aluminum hydroxide powder of (1-2): 1.
Preferably, if the aluminum source contains impurity element sodium, the content of the element sodium is required to be less than 100ppm, and preferably less than 30 ppm.
In the step (1), the peptizing agent is a nitric acid aqueous solution, and preferably the nitric acid aqueous solution with the mass fraction of 10-68%.
In step (1) of the present invention, the mass ratio of the aluminum source (in terms of alumina) to the peptizing agent and water is 1: (0.06-0.2): (1.1 to 3.2), preferably 1: (0.06-0.15): (1.5-2.5), wherein the water comprises moisture contained in an aluminum source.
In the step (1), the stirring speed is 200-500 rpm.
In step (2) of the present invention, the copper salt is any one or a combination of at least two of copper chloride dihydrate, copper nitrate and copper acetate, and is preferably copper chloride dihydrate.
In step (2) of the present invention, the niobium salt is any one or a combination of at least two of niobium oxalate, ammonium niobium oxalate and niobic acid, and is preferably niobium oxalate.
In the step (2) of the invention, the mass ratio of the copper salt (calculated by copper element) to the niobium salt (calculated by niobium element) is (5-50): 1, preferably (10 to 44): 1;
the mass ratio of the total mass of the copper salt and the niobium salt to the water is 1: (4-10), preferably 1: (5-8).
In the step (2), the solution B is slowly added into the sol A, preferably in a continuous feeding mode, and more preferably in a dropwise adding mode;
preferably, the feeding time of the solution B is 1-120 min, preferably 1-30 min.
In the step (2), the stirring speed is 200-500 rpm; the stirring time is 0.5-3 h.
In the step (2) of the present invention, the viscosity of the slurry C is 1000 to 8000mPa · s, preferably 2000 to 5000mPa · s.
In the step (3) of the present invention, the drying may be in the form of oven drying, infrared drying, freeze drying, spray drying, etc., preferably centrifugal spray drying;
preferably, the drying is carried out, wherein the air inlet temperature is 180-250 ℃, and the air outlet temperature is 90-120 ℃.
In the step (3), the roasting temperature is 300-700 ℃, and preferably 400-550 ℃; the roasting time is 2-10 h, preferably 2-5 h; the roasting atmosphere is air.
In step (3) of the present invention, the Al containing Cu2O3-Nb2O5Microsphere D10>20 μm, D50 of 50-80 μm, D90<200μm。
In step (4) of the present invention, the alkali metal salt is any one of or a combination of at least two of hydrochloride, carbonate and nitrate of an alkali metal, preferably any one of or a combination of at least two of hydrochloride and carbonate of potassium and cesium.
In step (4) of the present invention, the magnesium salt is any one or a combination of two of magnesium chloride and magnesium nitrate, and is preferably magnesium chloride.
In step (4) of the present invention, the mass ratio of the alkali metal salt (in terms of alkali metal element) to the magnesium salt (in terms of magnesium element) is 1: (1 to 20), preferably 1: (3-16);
the mass ratio of the total mass of the alkali metal salt and the magnesium salt to the hydrochloric acid is 1: (4-10), preferably 1: (5-8).
In the step (4), the mass fraction of the hydrochloric acid is 5-15%, preferably 8-12%.
In the step (4) of the invention, the impregnation is a conventional operation in the field, the invention has no specific requirements on the dosage of the impregnation liquid, and Al containing copper element2O3-Nb2O5The microspheres can be completely immersed in the solution D, from the economic viewpoint, the microspheres can be just immersed in the solution D, or the solution D is preferably slightly excessive, the impregnation is preferably carried out at room temperature, and the impregnation time is preferably 0.1-2 h.
In the step (4), the drying mode comprises the steps of airing the surface moisture at room temperature, and then drying in an oven to constant weight;
preferably, the airing time is 1-4 h;
preferably, the drying temperature is 60-150 ℃, preferably 80-130 ℃, and the drying time is 8-24 hours, preferably 12-18 hours.
The catalyst can be used for catalyzing the oxychlorination of ethylene to 1, 2-dichloroethane in a fluidized bed process.
The invention provides a method for preparing 1, 2-dichloroethane by oxychlorination of ethylene, which adopts the ethylene oxychlorination catalyst of the invention and is carried out in a fluidized bed reactor, wherein the oxychlorination reaction conditions comprise that:
the volume ratio of the feed gas of hydrogen chloride to the ethylene and oxygen is 2: (1-1.1): (0.52-0.6) and a volume space velocity of 1400-2000 h-1；
The oxychlorination reaction is carried out at the temperature of 210-250 ℃ and under the pressure (absolute pressure) of 0.1-0.5 MPa.
The technical scheme of the invention has the beneficial effects that:
the catalyst of the invention has simple preparation steps, easy industrial production and mechanical strengthHigh antiwear performance and high stability. The Al formed after the niobium element is introduced into the invention2O3-Nb2O5Support with pure Al2O3Compared with the carrier, the carrier has stronger interaction force with copper salt, inhibits copper loss caused by copper migration, and can generate synergistic effect with active components of copper, magnesium, alkali metal elements such as potassium, cesium and the like after the niobium element is introduced, thereby enhancing the activity and stability of the catalyst. In addition, the introduced alkali metal can further improve the activity and selectivity of the catalyst by adjusting the acid sites on the surface of the catalyst.
When the catalyst is applied to the reaction of catalyzing the oxychlorination of ethylene to 1, 2-dichloroethane, the conversion rate of hydrogen chloride is higher than 99% and the EDC selectivity reaches more than 97% at the hot spot temperature of about 210-230 ℃.
Detailed Description
In order to better understand the technical solution of the present invention, the following further illustrates the content of the present invention with reference to the examples, but the content of the present invention is not limited thereto.
The test methods used in the examples or comparative examples are described below:
1. analysis of reaction products
The product was analyzed by chromatography using a gas chromatograph model GC-2014 of Shimadzu, Japan:
a chromatographic column: two P-N columns (1m, maximum service temperature 190 ℃), and one MS-13X molecular sieve packed column (2m, maximum service temperature 350 ℃);
DB-5 capillary column (30m 0.32mm 0.25 μm);
sample inlet temperature: 280 ℃;
detector temperature: 300 ℃;
the split ratio is as follows: 50: 1;
column flow rate: 1.5 ml/min;
temperature program of chromatographic column: keeping the temperature at 50 ℃ for 2min, heating to 80 ℃ at 5 ℃/min, heating to 280 ℃ at 15 ℃/min, and staying for 5 min.
The calculation formula of the conversion rate of raw materials and the selectivity of each product in the reaction process is as follows:
HCl conversion ═ mol HCl converted in the reactor/mol HCl supplied to the reactor × 100%
Ethylene conversion ═ mol ethylene converted in the reactor/mol ethylene supplied to the reactor x 100%
EDC selectivity (%) × 100% (mol ethylene converted to 1, 2-dichloroethane/mol ethylene total converted)
COx selectivity (%) - (mol ethylene converted to COx/mol ethylene total converted) × 100%
Chlorine-containing by-product selectivity (%) - (mol ethylene converted to chlorine-containing by-product/mol ethylene converted in total) × 100%
2. Determination of catalyst attrition index
The abrasion index was measured according to the method of Standard "straight tube method for measuring abrasion index of catalytic cracking catalyst" Q/TSH 349092006.
3. Method for measuring viscosity of catalyst slurry
The measurement is carried out by adopting a Shanghai Changji NDJ-1B rotational viscometer, and a No. 3 rotor is selected for the measurement, and the rotating speed is 60 revolutions per minute.
4. Method for measuring pore structure information of catalyst
The BET specific surface area, BJH desorption pore volume and pore diameter of the catalyst are measured by a low-temperature nitrogen physical adsorption method, and the instrument model is Micrometics ASAP 2460 produced by American Mike corporation.
The metal salt raw materials used in the examples or comparative examples of the present invention were purchased from west longum chemical corporation, pseudo-boehmite was purchased from shandong yineng catalytic technology, ltd, activated alumina powder was purchased from suzhou beierde new material science and technology, ltd, and aluminum hydroxide powder was purchased from shandong aluminum;
other raw materials are all common commercial raw materials unless otherwise specified.
Example 1
The preparation of the ethylene oxychlorination catalyst comprises the following steps:
(1) 80g of pseudo-boehmite (the content of alumina is 60 wt%, the content of sodium is 10ppm), 55g of aluminum hydroxide powder (the content of sodium is 27ppm) and 150g of deionized water are weighed and added into a peptization kettle, and the materials are stirred and mixed uniformly at the rotating speed of 300 rpm. Then 8g of concentrated nitric acid (68% wt) was added to the kettle and stirring was continued to obtain sol A.
(2) 15g (0.088mol) of copper chloride dihydrate and 1.21g (0.002mol) of niobium oxalate were weighed out and dissolved in 100g of deionized water to obtain solution B. Slowly dripping the solution B into the sol A, adding for 20min, and stirring at 500rpm for 1h to obtain slurry C with the viscosity of 3000 mPas.
(3) Centrifugally spray-drying the slurry C (the inlet air temperature is 250 ℃, the outlet temperature is 110 ℃), roasting the slurry C in the air for 4 hours at the temperature of 500 ℃, and screening to obtain about 113g of copper-containing Al2O3-Nb2O5The microsphere has the particle size distribution of D10 ═ 25 μm, D50 of 70 μm and D90 of 190 μm.
(4) 6g (0.063mol) of magnesium chloride, 0.5g (0.007mol) of potassium chloride and 0.3g (0.001mol) of cesium carbonate were weighed out and dissolved in 40g of hydrochloric acid (10 wt%) to obtain solution D. Al containing copper element2O3-Nb2O5And adding the microspheres into the solution D, soaking for 0.5h at room temperature, airing for 1h at room temperature, drying for 10h at 80 ℃ and drying for 4h at 130 ℃ to obtain the finished product of the ethylene oxychlorination catalyst.
The ethylene oxychlorination catalyst prepared in this example has Al as the carrier2O3-Nb2O5The active components comprise copper, potassium, cesium and magnesium, and are in the form of chlorides; the mass content of the metal elements contained in the catalyst is 4.63 percent of copper element, 1.26 percent of magnesium element, 0.22 percent of potassium element, 0.21 percent of cesium element, 0.17 percent of niobium element and 44.62 percent of aluminum element, wherein the total mass of the catalyst is 100 percent;
the pore structure properties and the measured values of the attrition index of the catalyst are shown in Table 1.
Ethylene oxychlorination is carried out to prepare 1, 2-dichloroethane, and the steps are as follows:
40g of the ethylene oxychlorination catalyst prepared in this example were placed in a fluidized bed reactor having an internal diameter of 30mm and a height of 600mm, with a feed gas volume ratio of hydrogen chloride: ethylene: oxygen gas is 2:1.02:0.55, space velocity is 1800h-1The reaction temperature is 220 ℃, and the reaction pressure is 0.3 MPa.
And analyzing the composition of the reaction product by gas chromatography, and obtaining the conversion rate of the hydrogen chloride by an acid-base titration method. After 24 hours of operation, the catalyst activity evaluation results at different hotspot temperatures are shown in tables 2, 3 and 4. The results of the catalyst activity evaluations at different hotspot temperatures after 1000h of operation are shown in tables 5, 6 and 7.
After running for 1000h, the catalyst was disassembled, the copper content in the catalyst was analyzed, and the catalyst fluidity was observed, with the results shown in table 8.
Example 2
The preparation of the ethylene oxychlorination catalyst comprises the following steps:
(1) 80g of pseudo-boehmite (the content of alumina is 60 wt%, and the content of sodium is 10ppm) and 210g of alumina sol (the content of alumina is 25 wt%, and the content of sodium is 10ppm) are weighed and added into a peptizing kettle, and the materials are stirred and mixed uniformly at the rotating speed of 250 rpm. Then 7g of concentrated nitric acid (68% wt) was added to the kettle and stirring was continued to obtain sol A.
(2) 12g (0.070mol) of copper chloride dihydrate and 3.64g (0.007mol) of niobium oxalate were weighed out and dissolved in 100g of deionized water to obtain a solution B. Slowly adding the solution B into the sol A for 2min, and stirring at 350rpm for 1h to obtain slurry C with the viscosity of 2000 mPas.
(3) Centrifugally spray-drying the slurry C (the inlet air temperature is 250 ℃, the outlet temperature is 110 ℃), roasting the slurry C in air for 4 hours at the temperature of 450 ℃, and screening to obtain about 110g of copper-containing Al2O3-Nb2O5The microsphere has the particle size distribution of 21 microns D10, 55 microns D50 and 170 microns D90.
(4) 4.5g (0.047mol) of magnesium chloride and 1.1g (0.015mol) of potassium chloride were weighed out and dissolved in 50g of hydrochloric acid (7 wt%) to obtain a solution D. Al containing copper element2O3-Nb2O5And adding the microspheres into the solution D, soaking for 2h at room temperature, airing for 2h at room temperature, drying for 8h at 80 ℃, and drying for 12h at 120 ℃ to obtain the finished product of the ethylene oxychlorination catalyst.
The ethylene oxychlorination catalyst prepared in this example has Al as the carrier2O3-Nb2O5The active components comprise copper, potassium and magnesium, which are all in the form of chloride; to be provided withThe total mass of the catalyst is 100 percent, and the mass content of metal elements contained in the catalyst is 3.82 percent of copper element, 1.08 percent of magnesium element, 0.49 percent of potassium element, 0.54 percent of niobium element and 45.49 percent of aluminum element;
the pore structure properties and the measured values of the attrition index of the catalyst are shown in Table 1.
Ethylene oxychlorination to 1, 2-dichloroethane was carried out in the same manner as in example 1.
Example 3
The preparation of the ethylene oxychlorination catalyst comprises the following steps:
(1) 80g of pseudo-boehmite (the content of alumina is 60 wt%, and the content of sodium is 5ppm), 20g of active alumina powder (the content of sodium is 15ppm) and 120g of deionized water are weighed and added into a peptization kettle, and the materials are stirred and mixed uniformly at the rotating speed of 450 rpm. Then 10g of concentrated nitric acid (68% wt) was added to the kettle and stirring was continued to obtain sol A.
(2) 13g (0.076mol) of copper chloride dihydrate and 2.43g (0.005mol) of niobium oxalate were weighed out and dissolved in 100g of deionized water to obtain a solution B. Slowly adding the solution B into the sol A for 100min, and stirring at the rotating speed of 250rpm for 1h to obtain slurry C with the viscosity of 4800 mPas.
(3) Centrifugally spray-drying the slurry C (the inlet air temperature is 250 ℃, the outlet temperature is 110 ℃), roasting at 550 ℃ for 4h, and screening to obtain about 78g of copper-containing Al2O3-Nb2O5The microsphere has the particle size distribution of D10 ═ 30 μm, D50 of 75 μm and D90 of 160 μm.
(4) 8g (0.084mol) of magnesium chloride, 0.5g (0.007mol) of potassium chloride and 0.15g (0.0005mol) of cesium carbonate were weighed out and dissolved in 35g of hydrochloric acid (13 wt%) to obtain a solution D. Al containing copper element2O3-Nb2O5And adding the microspheres into the solution D, soaking for 0.2h at room temperature, airing for 3h at room temperature, drying for 15h at 60 ℃ and drying for 6h at 140 ℃ to obtain the finished product of the ethylene oxychlorination catalyst.
The ethylene oxychlorination catalyst prepared in this example has Al as the carrier2O3-Nb2O5The active components comprise copper, potassium, cesium and magnesium, and are in the form of chlorides; the metal element substance contained in the catalyst is calculated by taking the total mass of the catalyst as 100 percentThe content of copper element 5.53%, magnesium element 2.31%, potassium element 0.3%, cesium element 0.14%, niobium element 0.48%, and aluminum element 41.14%;
the pore structure properties and the measured values of the attrition index of the catalyst are shown in Table 1.
Ethylene oxychlorination to 1, 2-dichloroethane was carried out in the same manner as in example 1.
Example 4
An ethylene oxychlorination catalyst was prepared by referring to example 1, except that in step (4), potassium was used as the alkali metal, that is, 0.5g of potassium chloride, 0.3g of cesium carbonate was replaced with 0.8g (0.011mol) of potassium chloride, and the operation and parameters were the same as in example 1.
The ethylene oxychlorination catalyst prepared in this example has Al as the carrier2O3-Nb2O5The active components comprise copper, potassium and magnesium, which are all in the form of chloride; the mass content of the metal elements contained in the catalyst is 4.63 percent of copper element, 1.26 percent of magnesium element, 0.35 percent of potassium element, 0.17 percent of niobium element and 44.63 percent of aluminum element, wherein the total mass of the catalyst is 100 percent;
the pore structure properties and the measured values of the attrition index of the catalyst are shown in Table 1.
Ethylene oxychlorination to 1, 2-dichloroethane was carried out in the same manner as in example 1.
Example 5
An ethylene oxychlorination catalyst was prepared by referring to example 1, except that only cesium was used as the alkali metal in step (4), that is, 0.5g of potassium chloride, 0.3g of cesium carbonate were replaced with 0.8g of cesium carbonate (0.002mol), and the operation and parameters were the same as in example 1.
The ethylene oxychlorination catalyst prepared in this example has Al as the carrier2O3-Nb2O5The active components comprise copper, cesium and magnesium, and are in the form of chlorides; the mass content of the metal elements contained in the catalyst is 4.63 percent of copper element, 1.26 percent of magnesium element, 0.56 percent of cesium element, 0.17 percent of niobium element and 44.62 percent of aluminum element, wherein the total mass of the catalyst is 100 percent;
the pore structure properties and the measured values of the attrition index of the catalyst are shown in Table 1.
Ethylene oxychlorination to 1, 2-dichloroethane was carried out in the same manner as in example 1.
Comparative example 1
Preparation of catalyst an ethylene oxychlorination catalyst was prepared by referring to example 1, except that in step (2) no niobium oxalate was added, namely 15g of copper chloride dihydrate was weighed and dissolved in 100g of deionized water to obtain solution B, and other operations and parameters were the same as in example 1.
The pore structure properties and the measured values of the attrition index of the catalyst are shown in Table 1.
Ethylene oxychlorination to 1, 2-dichloroethane was carried out in the same manner as in example 1.
Comparative example 2
Preparation of catalyst an ethylene oxychlorination catalyst was prepared by referring to the method of example 1, except that 80g of pseudo-boehmite (alumina content 60 wt%, sodium content 10ppm) and 55g of aluminum hydroxide powder (sodium content 27ppm) were replaced with 80g of pseudo-boehmite (alumina content 60 wt%, sodium content 1000ppm) and 55g of aluminum hydroxide powder (sodium content 300ppm) in step (1), and the operation and parameters were the same as in example 1.
The pore structure properties and the measured values of the attrition index of the catalyst are shown in Table 1.
Ethylene oxychlorination to 1, 2-dichloroethane was carried out in the same manner as in example 1.
Comparative example 3
The preparation method of the catalyst comprises the following steps:
90g of high purity activated alumina (brand PURALOX SCCa-25/200) manufactured by SASOL corporation was weighed as a catalyst carrier.
15g of copper chloride dihydrate, 6g of magnesium chloride, 0.5g of potassium chloride and 0.3g of cesium carbonate were weighed out and dissolved in 40g of water to obtain an active component solution. And (3) soaking the solution on a SASOL carrier, airing at room temperature for 1h, drying at 80 ℃ for 10h, and drying at 130 ℃ for 4h to obtain a catalyst finished product.
The pore structure properties and the measured values of the attrition index of the catalyst are shown in Table 1.
Ethylene oxychlorination to 1, 2-dichloroethane was carried out in the same manner as in example 1.
Comparative example 4
The catalyst was prepared by the method of reference example 1 except that in step (4), no alkali metal elements potassium and cesium were added, that is, only 6g of magnesium chloride was weighed and dissolved in 40g of water to obtain solution D, and the other operations and parameters were the same as in example 1.
The pore structure properties and the measured values of the attrition index of the catalyst are shown in Table 1.
Ethylene oxychlorination to 1, 2-dichloroethane was carried out in the same manner as in example 1.
Comparative example 5
The catalyst was prepared by the method of reference example 1 except that no magnesium element was introduced in step (4), namely, 0.5g of potassium chloride and 0.3g of cesium carbonate were weighed and dissolved in 40g of water to obtain solution D, and the other operations and parameters were the same as in example 1.
The pore structure properties and the measured values of the attrition index of the catalyst are shown in Table 1.
Ethylene oxychlorination to 1, 2-dichloroethane was carried out in the same manner as in example 1.
TABLE 1 basic physical Properties parameters of the catalysts
Wear index/%
Specific surface area/m2/g
Pore volume/ml/g
Average pore diameter/nm
Example 1
0.56
163
0.39
8.77
Example 2
0.39
147
0.43
8.35
Example 3
0.78
152
0.38
9.18
Example 4
0.63
143
0.36
8.22
Example 5
0.61
141
0.35
8.19
Comparative example 1
3.11
139
0.33
7.31
Comparative example 2
2.67
144
0.36
7.78
Comparative example 3
1.25
156
0.40
8.11
Comparative example 4
1.33
161
0.41
9.21
Comparative example 5
1.56
158
0.40
9.02
TABLE 2 evaluation results of catalyst activity (Hot Point 210 ℃ C., reaction 24 hours)
TABLE 3 evaluation of the activity of the catalyst (hotspot 220 ℃ C., reaction 24h)
HCl conversion/%)
Ethylene conversion/%
EDC selectivity/%
COx selectivity/%)
Selectivity of Cl-containing by-product/%)
Example 1
99.61
96.88
97.28
0.75
1.97
Example 2
99.38
97.17
97.91
0.66
1.43
Example 3
99.47
97.41
97.52
0.59
1.89
Example 4
99.36
96.83
97.23
0.76
2.01
Example 5
99.34
96.79
97.21
0.77
2.02
Comparative example 1
98.06
95.23
97.26
0.35
2.39
Comparative example 2
98.73
95.92
96.61
0.64
2.75
Comparative example 3
99.34
96.62
96.71
0.77
2.52
Comparative example 4
99.22
96.33
96.44
0.62
2.94
Comparative example 5
99.14
96.11
96.52
0.67
2.81
TABLE 4 evaluation of the activity of the catalyst (hotspot 230 ℃ C., reaction time 24h)
HCl conversion/%)
Ethylene conversion/%
EDC selectivity/%
COx selectivity/%)
Selectivity of Cl-containing by-product/%)
Example 1
99.83
97.18
97.19
1.75
1.06
Example 2
99.79
97.35
97.62
1.38
1
Example 3
99.81
97.54
97.28
1.26
1.46
Example 4
99.75
97.14
97.45
1.47
1.08
Example 5
99.72
97.11
97.43
1.48
1.09
Comparative example 1
99.12
96.29
96.36
2.18
1.46
Comparative example 2
99.29
96.66
96.76
2.57
0.67
Comparative example 3
99.59
97.33
96.12
1.56
2.32
Comparative example 4
99.34
96.45
96.29
0.89
2.82
Comparative example 5
99.28
96.33
96.35
0.92
2.73
TABLE 5 evaluation of the activity of the catalyst (Hot Point 210 ℃ C., reaction 1000h)
TABLE 6 evaluation of the activity of the catalyst (hotspot 220 ℃ C., reaction 1000h)
HCl conversion/%)
Ethylene conversion/%
EDC selectivity/%
COx selectivity/%)
Selectivity of Cl-containing by-product/%)
Example 1
99.65
96.91
97.25
0.71
2.04
Example 2
99.41
97.19
97.95
0.59
1.46
Example 3
99.53
97.46
97.46
0.63
1.91
Example 4
99.38
96.87
97.23
0.73
2.04
Example 5
99.35
96.85
97.21
0.74
2.05
Comparative example 1
97.44
95.03
97.33
0.39
2.28
Comparative example 2
98.23
95.62
96.84
0.35
2.81
Comparative example 3
98.78
96.23
96.96
0.55
2.49
Comparative example 4
99.11
96.05
96.62
0.43
2.95
Comparative example 5
99.03
95.91
96.71
0.46
2.83
TABLE 7 evaluation results of catalyst activity (hotspot 230 ℃ C., reaction 1000h)
HCl conversion/%)
Ethylene conversion/%
EDC selectivity/%
COx selectivity/%)
Selectivity of Cl-containing by-product/%)
Example 1
99.84
97.16
97.21
1.78
1.01
Example 2
99.78
97.38
97.69
1.33
0.98
Example 3
99.86
97.61
97.24
1.31
1.45
Example 4
99.76
97.16
97.18
1.81
1.01
Example 5
99.74
97.15
97.17
1.79
1.04
Comparative example 1
98.95
95.66
96.42
2.11
1.47
Comparative example 2
99.01
96.43
96.81
2.43
0.76
Comparative example 3
99.23
97.05
96.41
1.38
2.21
Comparative example 4
99.26
96.37
96.46
0.65
2.89
Comparative example 5
99.18
96.19
96.58
0.63
2.79
TABLE 8 copper loss and flowability of the catalyst