CN115957775A - Catalyst for preparing styrene by ethylbenzene dehydrogenation and preparation method and application thereof - Google Patents
Catalyst for preparing styrene by ethylbenzene dehydrogenation and preparation method and application thereof Download PDFInfo
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Abstract
The invention relates to a catalyst for preparing styrene by ethylbenzene dehydrogenation and a preparation method and application thereof. The catalyst comprises Fe 2 O 3 、K 2 O、CeO 2 、WO 3 、MgO、Na 2 O; wherein, ceO 2 (111) Exposed crystal face area of CeO 2 More than 70% of the total exposed crystal plane area. The catalyst of the invention has high selectivity and high stability when being used for ethylbenzene dehydrogenation reaction.
Description
Technical Field
The invention relates to a catalyst for preparing styrene by ethylbenzene dehydrogenation, in particular to a catalyst for preparing styrene by ethylbenzene dehydrogenation with a low water ratio, and a preparation method and application thereof.
Background
The styrene monomer is the species with the simplest structure in unsaturated aromatic monomer series, is an important raw material in synthetic rubber and plastic industries, and plays an important role in national economy. The ethylbenzene catalytic dehydrogenation method is always the leading technical route for producing styrene at home and abroad, and the production capacity of the ethylbenzene catalytic dehydrogenation method accounts for more than 85 percent of the total production capacity of the styrene. To improve the efficiency of ethylbenzene dehydrogenation, large quantities of high temperature steam are typically introduced industrially. Steam plays a number of important roles in the reaction, such as providing the heat required for the reaction, promoting the shift of the chemical equilibrium towards styrene, eliminating catalyst surface coke deposition by the water gas shift reaction, oxidizing the catalyst surface to maintain catalyst activity, and the like. However, the large amount of superheated steam as the dehydrogenation medium makes the process large in energy consumption, large in product condensation amount, high in process equipment cost and high in production cost. The development of the high-selectivity styrene catalyst suitable for low water ratio realizes the energy conservation and consumption reduction of the styrene device and the reduction of the production cost, and becomes the urgent need of styrene enterprises.
Toluene and benzene are the major by-products of the catalytic dehydrogenation reaction of ethylbenzene. The byproduct benzene can be separated by the rectification unit and then returned to the ethylbenzene unit for recycling. The toluene with low economic value can only be sold as a byproduct at low price, the utilization rate of the raw material ethylbenzene can be improved by reducing the generation amount of the toluene, the material consumption of the device is reduced, and the economic benefit is increased. The styrene plant is preferably operated with a catalyst having good styrene selectivity. The prior styrene catalyst mostly takes Fe-K-Ce as a main catalyst, fe-K oxide as a main catalyst and Ce as a main auxiliary agent, and also contains structural stabilizers such as oxides of Mg, mo, W and Ca and electronic auxiliary agents. The presently disclosed ethylbenzene dehydrogenation catalyst with low water ratio mainly adopts the methods of improving the structural stability of the catalyst, modifying the surface property of the catalyst and the like to improve the stability, activity and selectivity of the catalyst under the condition of low water ratio. CN106582678A discloses that on the basis of a Fe-K-Ce-W catalyst, ba, sn and rare earth oxides (Sm, eu and Gd) are introduced to stabilize the active phase of the catalyst, so that the high activity and high stability of the catalyst under the condition of low water ratio are realized; CN101279269A discloses a catalyst with bismuth oxide and beryllium oxide added in an iron-potassium-cerium-tungsten-calcium catalytic system, which improves the stability and activity of an ethylbenzene dehydrogenation catalyst under the condition of low water ratio. The existing production method for preparing styrene by ethylbenzene dehydrogenation still has the problem of low styrene selectivity under the condition of low water ratio.
At present, the styrene production technology is developing towards the large-scale device and the comprehensive utilization of energy. In order to improve the economy of styrene production by ethylbenzene dehydrogenation, it is necessary to develop a catalyst for ethylbenzene dehydrogenation which is suitable for operation under low water ratio conditions, has high selectivity, and has better stability.
Disclosure of Invention
The invention aims to solve the technical problems of low catalyst selectivity and poor stability under the condition of low water ratio in the prior art of preparing styrene by ethylbenzene dehydrogenation, and provides a novel dehydrogenation catalyst for preparing styrene. The catalyst is used for ethylbenzene dehydrogenation reaction and has high selectivity and high stability.
The second technical problem to be solved by the present invention is to provide a method for preparing ethylbenzene dehydrogenation catalyst for preparing styrene corresponding to the first technical problem.
The present invention is also directed to a method for preparing styrene by dehydrogenation of ethylbenzene at a low water ratio using an ethylbenzene dehydrogenation catalyst.
In order to solve one of the technical problems, the technical scheme adopted by the invention is as follows:
in a first aspect, the invention provides a catalyst for preparing styrene by ethylbenzene dehydrogenation, wherein the catalyst comprises Fe 2 O 3 、K 2 O、CeO 2 、WO 3 、MgO、Na 2 O; wherein, ceO 2 (111) Exposed crystal face area in CeO 2 More than 70%, preferably more than 75% of the total exposed crystal plane area.
In the technical scheme, the catalyst comprises the following components in percentage by mass based on the total mass of the catalyst:
(a) 60-85% Fe 2 O 3 ；
(b) 6 to 14 percent of K 2 O；
(c) 6 to 14 percent of CeO 2 ；
(d) 0.5 to 5 percent of WO 3 ；
(e) 0.2 to 5 percent of MgO;
(f) 0.1 to 2 percent of Na 2 O。
In the above-mentioned aspect, it is preferable that the catalyst contains 0.01 to 1.0% by mass of oxides of other metals such as sm and/or La based on the total mass of the catalyst.
In the above technical solution, preferably, the CeO 2 (111) Exposed crystal face area of CeO 2 More than 75% of the total exposed crystal plane area; such as but not limited to 78%,80%,85%,87%,90%,92%,95%,97%,99%, etc.
To solve the second technical problem, the invention adopts the following technical scheme:
the second aspect of the present invention provides a preparation method of the above catalyst for preparing styrene by ethylbenzene dehydrogenation, comprising the following steps:
uniformly mixing a Fe source, a K source, a Ce source, a W source, a Mg source, a Na source and an optional pore-foaming agent, adding an alkaline solution, standing for reaction, forming and roasting to prepare the catalyst; the alkaline solution is tert-butylamine and/or ammonia solution.
In the above technical solution, the alkaline solution is a solution of tert-butylamine and/or ammonia water, preferably a solution of tert-butylamine and ammonia water; ammonia in alkaline solution as NH 3 ·H 2 The mass ratio of O to tert-butylamine is preferably 1-10: 1. the concentration of the alkaline solution is 0.5-5 mol/L. In the preparation method of the catalyst, the dosage of the alkaline solution is enough to ensure that the cerium source is dissolved in the liquid phase for reaction.
In the technical scheme, the Fe source is oxide Fe 2 O 3 Is added in the form of (1). The Fe source is preferably selected from red iron oxide and/or yellow iron oxide, more preferably a combination of red and yellow iron oxide, wherein red and yellow iron oxide are in the form of Fe 2 O 3 The mass ratio is 1.0-3.0. The K source is added in the form of potassium salt; the potassium salt is any one or more of potassium carbonate, potassium nitrate and potassium bicarbonate. The Ce source is added in the form of cerium salt; the cerium salt is cerium nitrate. The W source is added in the form of tungsten salt or oxide; the tungsten salt is ammonium tungstate. The Mg source is added in the form of an oxide or a magnesium salt. The magnesium salt is magnesium carbonate. The Na source was added as the sodium salt. The sodium salt is selected from one or more of sodium carbonate or sodium bicarbonate. The pore-forming agent is any one or more of activated carbon, graphite, sodium carboxymethylcellulose and polystyrene microspheres. The addition amount of the pore-foaming agent is 0-5% of the mass of the catalyst. In the preparation method of the catalyst, a Fe source, a K source, a Ce source, a W source, a Mg source, a Na source and a pore-forming agent are added in a solid powder mode.
In the technical scheme, the raw material also contains an Sm source and/or an La source; and mixing the Sm source and/or the La source with the Fe source, the K source, the Ce source, the W source, the Mg source, the Na source and the optional pore-foaming agent, and uniformly adding. The Sm source is added in the form of Sm salt or oxide; the Sm salt is one or two of samarium nitrate or samarium chloride. The La source is added in the form of La salt or oxide; the La salt is one or two of lanthanum nitrate or lanthanum chloride.
In the above technical solution, the mixing can be performed by a conventional mechanical stirring method.
In the technical scheme, the standing reaction condition is that the standing reaction is carried out for 12-48 h at 185-265 ℃. The vessel for the standing reaction is preferably an autoclave. The pressure of the standing reaction is not particularly limited.
In the above technical scheme, the molding can be performed by extruding a strip, and the strip can be a particle with a diameter of 2-5 mm and a length of 3-10 mm. If the reacted material can not meet the forming requirement, partial water can be removed by evaporation or the like or a proper amount of water is added, and then forming is carried out.
In the technical scheme, the roasting temperature is 600-1000 ℃, and the roasting time is 2-8 h.
In the above technical scheme, as a preferred roasting condition, two-step roasting is adopted, for example, but not limited to, roasting at 600-800 ℃ for 2-4 h, and then roasting at 900-1000 ℃ for 2-4 h. The firing is carried out in a muffle furnace.
In the above technical scheme, the formed material may be dried before being calcined. The drying temperature is 30-200 ℃, and the drying time is 1-24 h.
In order to solve the third technical problem, the third aspect of the present invention provides an application of the above catalyst in the preparation of styrene by ethylbenzene dehydrogenation.
In the technical scheme, the application of the catalyst in preparing styrene is suitable for ethylbenzene dehydrogenation with the water ratio of below 2.0, preferably 1.3-2.0.
In the technical scheme, the application of the ethylbenzene dehydrogenation catalyst in preparing styrene is suitable for ethylbenzene dehydrogenation under a low water ratio; the low water ratio is 1.3 or less, preferably 0.7 to 1.3.
In the above technical solution, the application includes: the ethylbenzene-containing raw material contacts with the catalyst of the invention in the presence of steam to carry out dehydrogenation reaction, and a styrene-containing product is obtained.
In the technical scheme, water is preheated to be water vapor before entering the reactor and is fully mixed with the raw material gas.
In the technical scheme, the temperature of the dehydrogenation reaction is 570-640 ℃.
In the technical scheme, the pressure of the dehydrogenation reaction is absolute pressure which is 20-100 kPa.
In the technical scheme, the mass space velocity of the ethylbenzene is 0.2-2.0 h -1 。
Compared with the prior art, the invention has the remarkable advantages and prominent effects as follows:
1. the crystal face effect of the catalyst has an important influence on the catalytic performance. The inventor finds out through research that the reaction performance of the Fe-K-Ce-W system ethylbenzene dehydrogenation catalyst and CeO in the catalyst 2 The surface structure of (A) is highly correlated, with different CeO 2 Exposing crystal planes can result in a significant difference in catalyst dehydrogenation selectivity and stability. The inventors have further studied and found that CeO 2 (111) Exposed crystal face area in CeO 2 The total exposed crystal face area is more than 70 percent, and the prepared catalyst is applied to ethylbenzene dehydrogenation reaction by matching with a main active component, namely iron sylvite of the catalyst, and has the outstanding advantages of few byproducts, high styrene selectivity and good stability.
2. In the invention, the inventor finds that the CeO in the catalyst can be well controlled by controlling the concentration of alkali in the solution and the wet reaction conditions in the hydrothermal synthesis preparation process 2 Surface structure of (5) CeO 2 (111) The exposed crystal face occupation ratio is high, the selectivity of a target product styrene in the ethylbenzene dehydrogenation reaction is improved, on the other hand, the preparation method promotes the interaction between the auxiliary component and the active component, and the stability of a crystal structure in the catalyst is improved. Compared with the conventional dry preparation method, the method is more beneficial to improving the catalytic performance, especially the selectivity, of the ethylbenzene dehydrogenation catalyst. The preparation process of the catalyst is simple, and the obtained catalyst has the advantages of high styrene selectivity and stable performance after the catalyst runs for 1000 hours.
3. The catalyst is used in the reaction of preparing styrene by ethylbenzene dehydrogenation, has high selectivity and high stability under low-to-high water ratio, especially low water ratio, and obtains better technical effect.
By adopting the technical scheme of the invention, the catalyst prepared by the invention is solidified in an isothermal mannerThe activity evaluation is carried out on a fixed bed at 70kPa (absolute pressure) and liquid space velocity of 1.0h -1 The styrene selectivity can be up to 96.8% or more as evaluated under the conditions of 620 ℃ and water ratio decreased from 2.0 (by weight) to 0.8 (by weight). After running for 1000 hours, the catalyst performance is kept stable, and the selectivity is not obviously changed. The catalyst of the invention obviously improves the selectivity and stability of the catalyst under the condition of low water ratio and obtains better technical effect.
Drawings
FIG. 1 is a graph of the major exposed crystal planes of the HAADF-STEM test of the catalyst obtained in example 1;
FIG. 2 is a graph of the major exposed crystal planes of the HAADF-STEM test of the catalyst obtained in comparative example 1.
Detailed Description
The invention is further illustrated by the following examples, without restricting its scope.
In the invention, the area of an exposed crystal face is tested by adopting a high-angle annular dark field image scanning transmission electron microscope (HAADF-STEM) characterization means, and a testing instrument is a Titan cube corner Themis G2 300 transmission electron microscope for correcting double spherical aberration of FEI company. CeO (CeO) 2 (111) Crystal face of CeO 2 The proportion of the total exposed crystal face area is obtained by counting and calculating HAADF-STEM morphology pictures and geometric structural characteristics of catalyst samples, namely the observed CeO 2 (111) Crystal face area in observed CeO 2 Proportion of total exposed crystal plane area. CeO (CeO) 2 Total exposed crystal face area of CeO 2 (100)、CeO 2 (110)、CeO 2 (111) And CeO 2 (311) Sum of exposed crystal plane areas. Observing the (111) exposed crystal plane by a scanning transmission electron microscope, wherein the spacing between the crystal planes visible in a plane vertical to the (111) observation direction is 305-335 pm, and the exposed crystal plane is CeO 2 (111)。
In the invention, the performance evaluation of the ethylbenzene dehydrogenation reaction is carried out on the catalyst in an isothermal fixed bed, and the process is briefly described as follows:
the reactor is a stainless steel tube with the inner diameter of 1' and is filled with 50-150 ml of catalyst with the diameter of 3-10 mm. Deionized water and ethylbenzene are respectively fed into a preheating mixer through a metering pump, preheated and mixed into a gas state, and then fed into a reactor, and the reactor is heated by an electric heating wire to reach a preset temperature. The composition of the reactants exiting the reactor was analyzed by gas chromatography after condensation of water.
The ethylbenzene conversion and the styrene selectivity are calculated according to the following formulas:
[ example 1 ] A method for producing a polycarbonate
Weighing up to 48.2 parts of Fe 2 O 3 23.6 parts of Fe 2 O 3 Iron oxide yellow of (1), corresponding to 11.2 parts of K 2 Potassium carbonate of O, corresponding to 10.9 parts of CeO 2 Corresponding to 1.6 parts of WO 3 Ammonium tungstate, 3.6 parts of magnesium oxide, equivalent to 0.7 part of Na 2 Sodium carbonate of O, 0.2 part of Sm 2 O 3 And 2.8 parts of polystyrene microspheres, and stirring in a mixer for 2 hours until the mixture is uniform. 1.9 parts of NH were added 3 ·H 2 O and 0.6 part
Mixed aqueous solution of tert-butylamine, NH in mixed aqueous solution 3 ·H 2 The total concentration of O and tert-butylamine was 2.4mol/L. The reaction was allowed to stand in an autoclave at 230 ℃ for 20 hours. And then, adjusting the water content of the mixture, extruding the mixture into strips, cutting the strips into granules to obtain granules with the diameter of 3 mm and the length of 6 mm, putting the granules into an oven, drying the granules for 4h at 80 ℃ and drying the granules for 4h at 160 ℃, then putting the granules into a muffle furnace, roasting the granules for 2h at 650 ℃ and roasting the granules for 2h at 900 ℃ to obtain the finished catalyst, wherein the composition of the catalyst is listed in Table 1.
100 ml of catalyst were charged to the reactor at 70kPa (abs.) and liquid space velocity of 1.0h -1 The performance was evaluated at 620 ℃ and a water ratio of 0.8 (wt). The test results for a reaction time of 100 hours are shown in Table 1, and the test results for a reaction time of 1000 hours are shown in Table 2.
[ example 2 ] A method for producing a polycarbonate
Weighed equivalent to 38.4 parts Fe 2 O 3 23.1 parts of Fe 2 O 3 Iron oxide yellow of (1), corresponding to 13.7 parts of K 2 Potassium carbonate of O, equivalent to 13.4 parts of CeO 2 Corresponding to 4.9 parts of WO 3 Ammonium tungstate, 3.7 parts of magnesium oxide, equivalent to 1.8 parts of Na 2 Sodium carbonate of O, 1.0 part of Sm 2 O 3 And 2.4 parts of polystyrene microspheres, and stirring in a mixer for 2 hours until the mixture is uniform. Then 3.8 parts of NH were added 3 ·H 2 O and 0.4 part
Mixed aqueous solution of tert-butylamine, NH in mixed aqueous solution 3 ·H 2 The total concentration of O and tert-butylamine was 4.8mol/L. The mixture is kept still in an autoclave for reaction for 48 hours at 190 ℃. And then, adjusting the water content of the mixture, extruding into strips, cutting into granules to obtain granules with the diameter of 3 mm and the length of 6 mm, putting the granules into an oven, drying for 4h at 80 ℃ and drying for 4h at 150 ℃, then putting the granules into a muffle furnace, roasting for 2h at 650 ℃ and roasting for 2h at 900 ℃ to obtain the finished catalyst, wherein the catalyst composition is listed in Table 1.
100 ml of catalyst were charged to the reactor at 70kPa (abs.) and liquid space velocity of 1.0h -1 The performance was evaluated at a temperature of 620 ℃ and a water ratio of 0.8 (wt), and the results of the test for 100 hours of reaction are shown in Table 1.
[ example 3 ] A method for producing a polycarbonate
Weighing equivalent to 45.2 parts of Fe 2 O 3 Iron oxide red of (1), 25.4 parts of Fe 2 O 3 Iron oxide yellow of (1), corresponding to 10.3 parts of K 2 Potassium carbonate of O, corresponding to 10.5 parts of CeO 2 Equivalent to 3.1 parts of WO 3 Ammonium tungstate, 4.55 parts of magnesium oxide, equivalent to 0.9 part of Na 2 Sodium carbonate of O, 0.05 part of Sm 2 O 3 And 0.5 part of polystyrene microspheres, and stirring for 2 hours in a mixer until the mixture is uniformly mixed. 1.7 parts of NH were added 3 ·H 2 Mixed aqueous solution of O and 0.5 part of tert-butylamine, NH in mixed aqueous solution 3 ·H 2 The total concentration of O and tert-butylamine was 2.1mol/L. The reaction was allowed to stand in an autoclave at 260 ℃ for 16 hours. Adjusting water content of the mixture, extruding into strips, cutting into granules with diameter of 3 mm and length of 6 mm, placing into oven, and heating at 80 deg.CDrying for 4h, drying at 150 ℃ for 4h, then placing in a muffle furnace, roasting at 650 ℃ for 2h, and roasting at 900 ℃ for 2h to obtain the finished catalyst, wherein the catalyst composition is listed in Table 1.
100 ml of catalyst were charged to the reactor at 70kPa (abs.) and liquid space velocity of 1.0h -1 The performance was evaluated at a temperature of 620 ℃ and a water ratio of 0.8 (wt), and the results of the test for 100 hours of reaction are shown in Table 1.
[ example 4 ] A method for producing a polycarbonate
Weighed 43.2 parts Fe 2 O 3 40.5 parts of Fe 2 O 3 Iron oxide yellow of (1), corresponding to 6.1 parts of K 2 Potassium carbonate of O, corresponding to 6.8 parts of CeO 2 Equivalent to 2.1 parts of WO 3 Ammonium tungstate, 0.2 part of magnesium oxide, equivalent to 0.7 part of Na 2 Sodium carbonate of O, 0.4 part of Sm 2 O 3 And 4.6 parts of polystyrene microspheres, and stirring in a mixer for 2 hours until the mixture is uniformly mixed. Then 0.6 part of NH is added 3 ·H 2 Mixed aqueous solution of O and 0.3 part of tert-butylamine, NH in mixed aqueous solution 3 ·H 2 The total concentration of O and tert-butylamine was 0.8mol/L. The reaction was allowed to stand in an autoclave at 200 ℃ for 40 hours. And then, adjusting the water content of the mixture, extruding into strips, cutting into granules to obtain granules with the diameter of 3 mm and the length of 6 mm, putting the granules into an oven, drying for 4h at 80 ℃ and drying for 4h at 150 ℃, then putting the granules into a muffle furnace, roasting for 2h at 650 ℃ and roasting for 2h at 900 ℃ to obtain the finished catalyst, wherein the catalyst composition is listed in Table 1.
100 ml of catalyst were charged to the reactor at 70kPa (abs.) and liquid space velocity of 1.0h -1 The performance was evaluated at a temperature of 620 ℃ and a water ratio of 0.8 (wt), and the results of the test for 100 hours of reaction are shown in Table 1.
[ example 5 ]
Weighed in an amount corresponding to 56.1 parts of Fe 2 O 3 Iron oxide red of (1), 19.1 parts of Fe 2 O 3 Iron oxide yellow of (1), corresponding to 8.9 parts of K 2 Potassium carbonate of O, corresponding to 8.5 parts of CeO 2 Equivalent to 2.6 parts of WO 3 Ammonium tungstate, 3.1 parts of magnesium oxide, equivalent to 0.8 part of Na 2 Sodium carbonate of O, 0.9 part of Sm 2 O 3 And 2.3 parts of polystyrene microspheres,stir in the mixer for 2h until well mixed. Then 1.0 part of NH was added 3 ·H 2 Mixed aqueous solution of O and 0.5 part of tert-butylamine, NH in mixed aqueous solution 3 ·H 2 The total concentration of O and tert-butylamine was 1.2mol/L. The reaction was allowed to stand in an autoclave at 240 ℃ for 18 hours. And then, adjusting the water content of the mixture, extruding into strips, cutting into granules to obtain granules with the diameter of 3 mm and the length of 6 mm, putting the granules into an oven, drying at 80 ℃ for 4h, drying at 160 ℃ for 4h, then putting the granules into a muffle furnace, roasting at 650 ℃ for 2h, and roasting at 900 ℃ for 2h to obtain the finished catalyst, wherein the catalyst composition is listed in Table 1.
100 ml of catalyst were charged into the reactor at 70kPa (abs.) and a liquid space velocity of 1.0h -1 The performance evaluation was performed at a temperature of 620 ℃ and a water ratio of 0.8 (wt), and the test results of the reaction for 100 hours are shown in Table 1 and the test results of the reaction for 1000 hours are shown in Table 2.
[ example 6 ]
Weighed corresponding to 47.6 parts of Fe 2 O 3 21.8 parts of Fe 2 O 3 Iron oxide yellow of (1), corresponding to 12.5 parts of K 2 Potassium carbonate of O, corresponding to 12.6 parts of CeO 2 Corresponding to 0.5 part of WO 3 Ammonium tungstate, 4.3 parts of magnesium oxide, equivalent to 0.5 part of Na 2 Sodium carbonate of O, 0.2 part of Sm 2 O 3 And 1.5 parts of polystyrene microspheres, and stirring in a mixer for 2 hours until the mixture is uniform. Then 2.6 parts of NH were added 3 ·H 2 O and 0.4 part
Mixed aqueous solution of tert-butylamine, NH in mixed aqueous solution 3 ·H 2 The total concentration of O and tert-butylamine was 3.2mol/L. The reaction was allowed to stand in an autoclave at 230 ℃ for 20 hours. And then, adjusting the water content of the mixture, extruding the mixture into strips, cutting the strips into granules to obtain granules with the diameter of 3 mm and the length of 6 mm, putting the granules into an oven, drying the granules for 4h at 80 ℃ and drying the granules for 4h at 150 ℃, then putting the granules into a muffle furnace, roasting the granules for 2h at 650 ℃ and roasting the granules for 2h at 900 ℃ to obtain the finished catalyst, wherein the composition of the catalyst is listed in Table 1.
100 ml of catalyst were charged into the reactor at 70kPa (abs.) and a liquid space velocity of 1.0h -1 The performance was evaluated at 620 ℃ and a water ratio of 0.8 (wt), and the results of the test for 100 hours of reaction are shown in Table 1.
[ example 7 ]
Weighed corresponding to 46.8 parts of Fe 2 O 3 Red iron oxide of (1), 23.2 parts of Fe 2 O 3 Iron oxide yellow of (1), corresponding to 11.6 parts of K 2 Potassium carbonate of O, corresponding to 11.3 parts of CeO 2 Equivalent to 2.1 parts of WO 3 Ammonium tungstate, 4.3 parts of magnesium oxide, equivalent to 0.1 part of Na 2 Sodium carbonate of O, 0.6 part of Sm 2 O 3 And 1.2 parts of polystyrene microspheres, and stirring in a mixer for 2 hours until the mixture is uniform. 1.8 parts of NH were added 3 ·H 2 O and 0.7 part
Mixed aqueous solution of tert-butylamine, NH in mixed aqueous solution 3 ·H 2 The total concentration of O and tert-butylamine was 2.2mol/L. The mixture was left to stand in an autoclave at 230 ℃ for 20 hours. And then, adjusting the water content of the mixture, extruding into strips, cutting into granules to obtain granules with the diameter of 3 mm and the length of 6 mm, putting the granules into an oven, drying for 4h at 80 ℃ and drying for 4h at 150 ℃, then putting the granules into a muffle furnace, roasting for 2h at 650 ℃ and roasting for 2h at 900 ℃ to obtain the finished catalyst, wherein the catalyst composition is listed in Table 1.
100 ml of catalyst were charged into the reactor at 70kPa (abs.) and a liquid space velocity of 1.0h -1 The performance was evaluated at a temperature of 620 ℃ and a water ratio of 0.8 (wt), and the results of the test for 100 hours of reaction are shown in Table 1.
[ example 8 ]
Weighed equivalent to 45.9 parts Fe 2 O 3 27.4 parts of Fe 2 O 3 Corresponding to 9.4 parts of K 2 Potassium carbonate of O, corresponding to 10.0 parts of CeO 2 Equivalent to 2.5 parts of WO 3 Ammonium tungstate, 3.1 parts of magnesium oxide, equivalent to 1.2 parts of Na 2 Sodium carbonate of O, 0.5 part of Sm 2 O 3 And 3.6 parts of polystyrene microspheres, and stirring in a mixer for 2 hours until the mixture is uniformly mixed. 1.4 parts of NH were added 3 ·H 2 Mixed aqueous solution of O and 1.2 parts of tert-butylamine, NH in mixed aqueous solution 3 ·H 2 The total concentration of O and tert-butylamine was 1.8mol/L. The reaction was allowed to stand in an autoclave at 220 ℃ for 20 hours. Then, the mixture is subjected to water content adjustment, and then is extruded into strips and cut into particles to obtain the product with the diameter of 3 mmAnd 6 mm long particles are put into an oven, dried at 80 ℃ for 4h and 150 ℃ for 4h, then placed into a muffle furnace, calcined at 650 ℃ for 2h and calcined at 900 ℃ for 2h to obtain the finished catalyst, and the composition of the catalyst is listed in Table 1.
100 ml of catalyst were charged to the reactor at 70kPa (abs.) and liquid space velocity of 1.0h -1 The performance was evaluated at a temperature of 620 ℃ and a water ratio of 0.8 (wt), and the results of the test for 100 hours of reaction are shown in Table 1.
[ example 9 ] A method for producing a polycarbonate
Weighed corresponding to 48.7 parts Fe 2 O 3 Iron oxide red of (1), 24.1 parts of Fe 2 O 3 Iron oxide yellow of (1), corresponding to 11.8 parts of K 2 Potassium nitrate of O, corresponding to 11.2 parts of CeO 2 Cerium nitrate of (1.8 parts of WO) 3 1.1 parts of magnesium oxide, equivalent to 1.0 part of Na 2 Sodium carbonate of O, 0.3 part of Sm 2 O 3 And 2.6 parts of polystyrene microspheres, and stirring in a mixer for 2 hours until the mixture is uniformly mixed. Then, 2.0 parts of NH was added 3 ·H 2 Mixed aqueous solution of O and 0.6 part of tert-butylamine NH in the mixed aqueous solution 3 ·H 2 The total concentration of O and tert-butylamine was 2.5mol/L. The reaction was allowed to stand in an autoclave at 230 ℃ for 20 hours. And then, adjusting the water content of the mixture, extruding into strips, cutting into granules to obtain granules with the diameter of 3 mm and the length of 6 mm, putting the granules into an oven, drying for 4h at 80 ℃ and drying for 4h at 150 ℃, then putting the granules into a muffle furnace, roasting for 2h at 650 ℃ and roasting for 2h at 900 ℃ to obtain the finished catalyst, wherein the catalyst composition is listed in Table 1.
100 ml of catalyst were charged into the reactor at 70kPa (abs.) and a liquid space velocity of 1.0h -1 The performance was evaluated at 620 ℃ and a water ratio of 0.8 (wt), and the results of the test for 100 hours of reaction are shown in Table 1.
[ example 10 ]
Weighed equivalent to 44.0 parts Fe 2 O 3 27.6 parts of Fe 2 O 3 Iron oxide yellow of (1), corresponding to 10.0 parts of K 2 Potassium carbonate of O, corresponding to 12.1 parts of CeO 2 Cerium nitrate of (5), 2.2 parts of WO 3 Magnesium carbonate equivalent to 1.8 parts of MgO, and Na equivalent to 1.5 parts of Na 2 Sodium hydrogen carbonate of O, corresponding to 0.8 part of Sm 2 O 3 Samarium nitrate and 2.7 parts of activated carbon are stirred in a mixer for 2 hours until the materials are uniformly mixed. 2.3 parts of NH were added 3 ·H 2 Mixed aqueous solution of O and 0.7 part of tert-butylamine, NH in mixed aqueous solution 3 ·H 2 The total concentration of O and tert-butylamine was 2.9mol/L. The reaction was allowed to stand in an autoclave at 230 ℃ for 20 hours. And then, adjusting the water content of the mixture, extruding into strips, cutting into granules to obtain granules with the diameter of 3 mm and the length of 6 mm, putting the granules into an oven, drying at 80 ℃ for 4h, drying at 160 ℃ for 4h, then putting the granules into a muffle furnace, roasting at 650 ℃ for 2h, and roasting at 900 ℃ for 2h to obtain the finished catalyst, wherein the catalyst composition is listed in Table 1.
100 ml of catalyst were charged to the reactor at 70kPa (abs.) and liquid space velocity of 1.0h -1 The performance was evaluated at 620 ℃ and a water ratio of 0.8 (wt). The test results for a reaction time of 100 hours are shown in Table 1, and the test results for a reaction time of 1000 hours are shown in Table 2.
[ example 11 ]
Weighing up to 48.2 parts of Fe 2 O 3 23.6 parts of Fe 2 O 3 Iron oxide yellow of (1), corresponding to 11.2 parts of K 2 Potassium carbonate of O, corresponding to 10.9 parts of CeO 2 Corresponding to 1.6 parts of WO 3 Ammonium tungstate, 3.6 parts of magnesium oxide, equivalent to 0.7 part of Na 2 Sodium carbonate of O, 0.2 part of La 2 O 3 And 2.8 parts of hydroxymethyl cellulose, and stirring in a mixer for 2 hours until uniformly mixed. 1.9 parts of NH were added 3 ·H 2 O and 0.6 part
Mixed aqueous solution of tert-butylamine, NH in mixed aqueous solution 3 ·H 2 The total concentration of O and tert-butylamine was 2.4mol/L. The reaction was allowed to stand in an autoclave at 230 ℃ for 20 hours. And then, adjusting the water content of the mixture, extruding into strips, cutting into granules to obtain granules with the diameter of 3 mm and the length of 6 mm, putting the granules into an oven, drying at 80 ℃ for 4h, drying at 160 ℃ for 4h, then putting the granules into a muffle furnace, roasting at 650 ℃ for 2h, and roasting at 900 ℃ for 2h to obtain the finished catalyst, wherein the catalyst composition is listed in Table 1.
100 ml of catalyst were charged to the reactor at 70kPa (abs.) and liquid space velocity of 1.0h -1 The performance evaluation was carried out at 620 ℃ with a water ratio of 0.8 (wt) and the reaction was carried out for 100 hoursThe test results are shown in Table 1.
[ example 12 ]
Weighing up to 48.2 parts of Fe 2 O 3 23.6 parts of Fe 2 O 3 Iron oxide yellow of (1), corresponding to 11.2 parts of K 2 Potassium carbonate of O, corresponding to 10.9 parts of CeO 2 Corresponding to 1.6 parts of WO 3 Ammonium tungstate, 3.6 parts of magnesium oxide, equivalent to 0.7 part of Na 2 Sodium carbonate of O, 0.2 part of Sm 2 O 3 And 2.8 parts of polystyrene microspheres, and stirring in a mixer for 2 hours until the mixture is uniformly mixed. 2.5 parts of NH were added 3 ·H 2 Aqueous solution of O, NH 3 ·H 2 The concentration of O was 2.4mol/L. The mixture was left to stand in an autoclave at 230 ℃ for 20 hours. And then, adjusting the water content of the mixture, extruding into strips, cutting into granules to obtain granules with the diameter of 3 mm and the length of 6 mm, putting the granules into an oven, drying at 80 ℃ for 4h, drying at 160 ℃ for 4h, then putting the granules into a muffle furnace, roasting at 650 ℃ for 2h, and roasting at 900 ℃ for 2h to obtain the finished catalyst, wherein the catalyst composition is listed in Table 1.
100 ml of catalyst were charged to the reactor at 70kPa (abs.) and liquid space velocity of 1.0h -1 The performance was evaluated at 620 ℃ and a water ratio of 0.8 (wt), and the results of the test for 100 hours of reaction are shown in Table 1.
[ example 13 ] to prepare a suspension
Weighing up to 48.2 parts of Fe 2 O 3 23.6 parts of Fe 2 O 3 Iron oxide yellow of (1), corresponding to 11.2 parts of K 2 Potassium carbonate of O, corresponding to 10.9 parts of CeO 2 Corresponding to 1.6 parts of WO 3 Ammonium tungstate, 3.6 parts of magnesium oxide, equivalent to 0.7 part of Na 2 Sodium carbonate of O, 0.2 part of Sm 2 O 3 And 2.8 parts of polystyrene microspheres, and stirring in a mixer for 2 hours until the mixture is uniformly mixed. 2.5 parts of an aqueous solution of tert-butylamine were added thereto, the concentration of tert-butylamine was 2.4mol/L. The reaction was allowed to stand in an autoclave at 230 ℃ for 20 hours. Then, the mixture is extruded and cut into particles with the diameter of 3 mm and the length of 6 mm after the water content is adjusted, the particles are put into an oven, dried for 4h at the temperature of 80 ℃ and dried for 4h at the temperature of 160 ℃, then put into a muffle furnace, roasted for 2h at the temperature of 650 ℃ and roasted for 2h at the temperature of 900 ℃ to obtain the productThe catalyst composition is shown in Table 1.
100 ml of catalyst were charged into the reactor at 70kPa (abs.) and a liquid space velocity of 1.0h -1 The performance evaluation was performed at a temperature of 620 ℃ and a water ratio of 0.8 (wt), and the test results of the reaction for 100 hours are shown in Table 1 and the test results of the reaction for 1000 hours are shown in Table 2.
Comparative example 1
Weighing up to 48.2 parts of Fe 2 O 3 23.6 parts of Fe 2 O 3 Iron oxide yellow of (1), corresponding to 11.2 parts of K 2 Potassium carbonate of O, corresponding to 10.9 parts of CeO 2 Corresponding to 1.6 parts of WO 3 Ammonium tungstate, 3.6 parts of magnesium oxide, equivalent to 0.7 part of Na 2 Sodium carbonate of O, 0.2 part of Sm 2 O 3 And 2.8 parts of polystyrene microspheres, and the same amount of water as in example 1 was added to the mixer, stirred for 2 hours until the mixture was uniformly mixed, and then allowed to stand in an autoclave at 230 ℃ for 20 hours. And then, adjusting the water content of the mixture, extruding the mixture into strips, cutting the strips into granules to obtain granules with the diameter of 3 mm and the length of 6 mm, putting the granules into an oven, drying the granules for 4h at 80 ℃ and drying the granules for 4h at 160 ℃, then putting the granules into a muffle furnace, roasting the granules for 2h at 650 ℃ and roasting the granules for 2h at 900 ℃ to obtain the finished catalyst, wherein the composition of the catalyst is listed in Table 1.
100 ml of catalyst were charged to the reactor at 70kPa (abs.) and liquid space velocity of 1.0h -1 The performance evaluation was performed at a temperature of 620 ℃ and a water ratio of 0.8 (wt), and the test results of the reaction for 100 hours are shown in Table 1 and the test results of the reaction for 1000 hours are shown in Table 2.
TABLE 1 catalyst composition, properties and evaluation results of examples and comparative examples
Note: * The ethylbenzene conversion rate and the styrene selectivity of the reaction are 100h under the water ratio of 0.8;
* Crystal plane ratio: ceO in catalyst 2 (111) Exposed crystal face area of CeO 2 Proportion of total exposed crystal plane area.
Table 2 catalyst stability evaluation results of examples and comparative examples
As can be seen from FIGS. 1 and 2, ceO was contained in the catalyst of example 1 2 Has CeO as main exposed crystal face 2 (111) A crystal plane. Comparative example 1 CeO in catalyst 2 Mainly exposed crystal face of CeO 2 (110) Crystal face, ceO 2 (110) Crystal face of CeO 2 The proportion of total exposed crystal planes of (a) is 62%. The results in tables 1 and 2 show that the catalyst has high selectivity and good stability, and the ethylbenzene selectivity is not obviously reduced after the dehydrogenation reaction is operated for 1000 hours.
The specific embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.
Claims (10)
1. A catalyst for the dehydrogenation of ethylbenzene to styrene, wherein said catalyst comprises Fe 2 O 3 、K 2 O、CeO 2 、WO 3 、MgO、Na 2 O; wherein, ceO 2 (111) Exposed crystal face area in CeO 2 More than 70%, preferably more than 75% of the total exposed crystal plane area.
2. The catalyst of claim 1, wherein: the catalyst comprises the following components in percentage by mass based on the total mass of the catalyst:
(a) 60-85% Fe 2 O 3 ；
(b) 6 to 14 percent of K 2 O；
(c) 6 to 14 percent of CeO 2 ；
(d) 0.5 to 5 percent of WO 3 ；
(e) 0.2 to 5 percent of MgO;
(f) 0.1-2% of Na 2 O。
3. The catalyst of claim 2, wherein: the catalyst contains 0.01 to 1.0 mass% of Sm and/or La metal oxide based on the total mass of the catalyst.
4. A process for preparing a catalyst according to any one of claims 1 to 3, characterized by comprising the steps of:
uniformly mixing a Fe source, a K source, a Ce source, a W source, a Mg source, a Na source and an optional pore-foaming agent, adding an alkaline solution, standing for reaction, forming and roasting to prepare the catalyst; the alkaline solution is tert-butylamine and/or ammonia solution.
5. The production method according to claim 4, wherein the concentration of the alkali solution is 0.5 to 5mol/L;
preferably, the alkaline solution is a solution of tert-butylamine and ammonia, the ammonia being NH 3 ·H 2 The mass ratio of O to tert-butylamine is preferably 1-10: 1.
6. the method according to claim 4, wherein the static reaction is carried out at 185 to 265 ℃ for 12 to 48 hours.
7. The preparation method according to claim 4, wherein the roasting temperature is 600-1000 ℃ and the roasting time is 2-8 h.
8. The production method according to any one of claims 4 to 7, wherein the Ce source is cerium nitrate;
and/or the source of Fe is the oxide Fe 2 O 3 Is added in the form of (1);
and/or the K source is added in the form of potassium salt;
and/or the W source is added in the form of a tungsten salt or oxide;
and/or the Mg source is added in the form of an oxide or hydroxide;
and/or the Na source is added in the form of a sodium salt.
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 the dehydrogenation of ethylbenzene to styrene.
10. Use according to claim 9, wherein the catalyst is suitable for the dehydrogenation of ethylbenzene at low water ratios; the low water ratio is 1.3 or less, preferably 0.7 to 1.3.
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