A catalyst for preparing lactone by coating diol dehydrogenation cyclization, a preparation method and application thereof

Abstract

The application discloses a kind of catalyst for preparing lactone by coating diol dehydrogenation cyclization, preparation method and application, and aluminium oxide in surface coating layer interacts with inner core porcelain ball during catalyst calcination process, and the compressive strength of catalyst is high;Strong alkaline adjuvant cesium and dehydrogenation adjuvant chromium are introduced, and the amount of hydrogenolysis, dehydration side reaction is less, and the dehydrogenation selectivity is high.The catalyst of the application greatly reduces the amount of non-ferrous metal, significantly reduces the cost of catalyst raw materials, and has low abrasion, small dust and less broken during production, transportation and loading.The catalyst of the application is especially suitable for near normal pressure reaction conditions due to uniform void after loading, less support house bridge and broken particles.

Description

Technical Field

[0001] This invention relates to a coated diol dehydrogenation cyclization catalyst for the preparation of lactones, its preparation method, and its application, belonging to the field of chemical catalysis technology. Background Technology

[0002] The dehydrogenation and cyclization of diols to prepare lactones, such as the dehydrogenation of 1,4-butanediol to prepare γ-butyrolactone, the dehydrogenation of 1,5-pentanediol to prepare δ-pentanelactone, the dehydrogenation of 1,6-hexanediol to prepare ε-caprolactone, and the dehydrogenation of diethylene glycol to prepare p-dioxanone, is a reaction route with high economic value. The lactone products obtained are widely used in solvents, organic synthesis intermediates, biodegradable materials and other fields.

[0003] Diol dehydrogenation cyclization reactions generally require high temperature, near-atmospheric pressure, or pressurized, hydrogen-containing conditions, and necessitate the assistance of a catalyst to lower the reaction energy barrier, increase the reaction rate, and achieve a high lactone yield (≥90%). Currently, commonly used catalyst systems are primarily copper-based, such as Cu-Zn-Cr-Zr (CN1054843A), Cr-Cr-Mn-Ba (CN1081948A), and Cu-Zn-Al. These catalysts typically contain high levels of non-ferrous metals, generally 30-50%, and are often formed using a tableting method. Many metal species are embedded within the catalyst, becoming ineffective sites and failing to be fully utilized, resulting in high catalyst production costs. Given the increasingly fierce competition in industries such as γ-butyrolactone, manufacturers urgently need to reduce production costs and improve product competitiveness. Therefore, reducing the amount of non-ferrous metals in diol dehydrogenation cyclization catalysts and improving catalytic efficiency has become a hot research topic in the industry.

[0004] The dehydrogenation and cyclization of glycols are often accompanied by the formation of byproducts. For example, the dehydrogenation of 1,4-butanediol to γ-butyrolactone may also generate lighter components such as dihydrofuran, tetrahydrofuran, n-butanol, and 2-hydroxytetrahydrofuran, as well as heavier components such as various C8 acetals like 2-(4-hydroxybutoxy)tetrahydrofuran, various C8 esters like butyl butyrate, and even heavier components. Tetrahydrofuran is a product of the dehydration of 1,4-butanediol or the dehydrogenation of n-butanol; n-butanol is a product of the hydrogenolysis of 1,4-butanediol; and 2-(4-hydroxybutoxy)tetrahydrofuran is a product of the polycondensation of a dehydrogenation intermediate and 1,4-butanediol. When 1,4-butanediol remains on the catalyst surface for too long, a large number of side reactions such as dehydration, hydrogenolysis, and polycondensation occur, leading to a decrease in the yield of γ-butyrolactone.

[0005] Furthermore, when the reaction temperature is too low, the rate at which intermediate products of the 1,4-butanediol dehydrogenation reaction, such as 2-hydroxytetrahydrofuran, are further converted into γ-butyrolactone is slowed down. 2-hydroxytetrahydrofuran and 1,4-butanediol then react to generate a large amount of hemiacetals and acetals such as 2-(4-hydroxybutoxy)tetrahydrofuran. This not only reduces the yield of the γ-butyrolactone main product, but also covers the active sites of the catalyst, affecting the catalyst's operating life.

[0006] With the scaling up and enlarging of reaction units, the diameter and length of the tubes in dehydrogenation reactors have shown a significant increasing trend. However, the heat transfer capacity of existing catalysts is limited, and the internal cold point temperature of the reaction tubes is too low. As a result, a large amount of the aforementioned heavy component byproducts will be generated and discharged from the bottom of the subsequent heavy component removal distillation column along with unreacted 1,4-butanediol. Since 1,4-butanediol and 2-(4-hydroxybutoxy)tetrahydrofuran have similar boiling points, they are difficult to separate. The bottom liquid cannot be used efficiently and mostly has to be incinerated, resulting in economic losses. Summary of the Invention

[0007] To address the aforementioned industry pain points, this invention provides a catalyst for the dehydrogenation cyclization of glycols to prepare lactones.

[0008] The technical solution of the present invention is as follows:

[0009] A catalyst for the dehydrogenation cyclization of glycols to prepare lactones, the catalyst being a coated type comprising a core and a coating layer; the core being a porous inert ceramic ball, and the coating layer being a mixture containing copper, silicon, aluminum, cesium, and chromium.

[0010] The porous inert ceramic ball is a mixture of inert alumina and silicon oxide or inert alumina. In the core porous inert ceramic ball, the mass ratio of silicon oxide to alumina is 0 to 1, for example, it can be 0 (in which case it is pure alumina), 0.3, 0.6, 0.8, 1, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0011] The diameter of the core porous inert ceramic ball is 2 to 5 mm, for example, it can be 2 mm, 3 mm, 4 mm, 5 mm, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0012] Preferably, based on the core mass, the water absorption rate of the porous inert ceramic ball in the core is 5-20%, for example, it can be 5%, 10%, 15%, 20%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0013] Preferably, the thermal conductivity of the core porous inert ceramic ball is 10 to 30 W / (m·K), for example, it can be 10 W / (m·K), 17 W / (m·K), 24 W / (m·K), 30 W / (m·K), etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0014] The copper, silicon, aluminum, cesium, and chromium elements in the coating layer exist in oxidized form, such as copper oxide, silicon oxide, aluminum oxide, cesium oxide, silicates, aluminates, chromium oxide, chromates, dichromates, or composite oxides or compounds composed of two or more of the above elements;

[0015] Preferably, the thickness of the coating layer is 0.5 to 3 mm, for example, it can be 0.5 mm, 1 mm, 1.5 mm, 2 mm, 3 mm, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0016] In one embodiment, the coating layer of the catalyst comprises, as a coating layer, 4-20 wt% copper oxide, 4-20 wt% silicon oxide, 0.05-5 wt% cesium oxide, 0.4-10 wt% chromium oxide (calculated as chromium trioxide), and 45-91.55 wt% aluminum oxide.

[0017] More preferably, it comprises 5-15 wt% copper oxide, 5-15 wt% silicon oxide, 0.1-3% cesium oxide, 0.5-3% chromium trioxide and 64-89.4% aluminum oxide;

[0018] Preferably, based on the coating layer, the copper oxide content is 5 to 15 wt%, for example, it can be 5 wt%, 8 wt%, 11 wt%, 13 wt%, 15 wt%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0019] Preferably, based on the coating layer, the silicon oxide content is 5 to 15 wt%, for example, it can be 5 wt%, 8 wt%, 11 wt%, 13 wt%, 15 wt%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0020] Preferably, based on the coating layer, the cesium oxide content is 0.1 to 3 wt%, for example, it can be 0.1 wt%, 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0021] Preferably, based on the coating layer, the chromium oxide (calculated as chromium trioxide) content is 0.5 to 3 wt%, for example, it can be 0.5 wt%, 1.0 wt%, 1.7 wt%, 2.4 wt%, 3 wt%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0022] Preferably, based on the coating layer, the alumina content is 64 to 89.4 wt%, for example, it can be 64 wt%, 70 wt%, 76 wt%, 82 wt%, 89.5 wt%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0023] This type of catalyst features a uniform distribution of active species on its outer layer, significantly reducing the amount of non-ferrous metals used and substantially lowering production costs. More importantly, it avoids the drawback of excessive residence time caused by diol diffusion into the catalyst interior, thereby reducing the likelihood of side reactions such as hydrogenolysis, dehydration, and polycondensation at the catalyst's active sites and improving lactone yield. Furthermore, since dehydrogenation is a strongly endothermic reaction, the highly thermally conductive inert ceramic ball core allows for rapid external heat supply, preventing excessively low cold-point temperatures in the catalyst bed within the reaction tube. This further suppresses the formation of high-boiling-point species such as hemiacetals and acetals, further extending the catalyst's lifespan. In some application examples, the catalyst operated stably for 8000 hours without any decrease in catalytic performance.

[0024] This invention also provides a method for preparing a diol dehydrogenation catalyst, which mainly includes the following steps:

[0025] (1) Dissolve and disperse a copper source, a cesium source, a chromium source or their solutions in ammonia water to obtain a mixed solution X;

[0026] (2) Add silicon source and aluminum source to mixed solution X, and then heat up to evaporate ammonia to obtain precursor;

[0027] (3) Mix the precursor and binder aqueous solution and coat it onto the core;

[0028] (4) The coated product is dried and calcined to obtain the coated catalyst product.

[0029] In step (1), the copper source can be one or more of copper nitrate, copper carbonate, basic copper carbonate, copper hydroxide, copper formate, copper acetate, copper oxalate, copper citrate, copper oxide, cuprous oxide, and copper powder.

[0030] The cesium source can be one or more of cesium nitrate, cesium carbonate, cesium hydroxide, cesium formate, cesium acetate, cesium oxalate, cesium citrate, and cesium oxide.

[0031] The chromium source may be one or more of chromium nitrate, chromium carbonate, chromium hydroxide, chromium formate, chromium acetate, chromium oxalate, chromium citrate, chromium trioxide, chromium dioxide, chromium trioxide, chromate, and dichromate.

[0032] The ammonia concentration is 10-50 wt%, for example, it can be 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0033] The order in which the copper source, cesium source, chromium source, or their solution are added to ammonia water is not limited, and the solution is an aqueous solution.

[0034] The dissolution and dispersion temperature is 10 to 60°C, for example, it can be 10°C, 25°C, 40°C, 50°C, 60°C, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0035] The dissolution and dispersion operations are carried out during stirring, with no display of the stirring speed and no time limit for dissolution and dispersion, ultimately resulting in a mixed solution X, in which the components of the liquid or slurry are uniformly mixed and distributed.

[0036] In step (2), the silicon source may be one or more of silicon dioxide, silica sol, aluminosilicate sol, tetramethyl silicate, and tetraethyl silicate.

[0037] The aluminum source may be one or more of the following: aluminum nitrate, aluminum carbonate, aluminum hydroxide, aluminic acid, aluminate, aluminum formate, aluminum acetate, aluminum oxalate, aluminum citrate, aluminum alkoxides, alkyl aluminum compounds, hydrated alumina, alumina, aluminum powder, silica-alumina sol, and aluminum sol.

[0038] The order in which the silicon source and aluminum source are added is not limited; they can be added as pure substances or as aqueous solutions added to the mixed solution X.

[0039] The heating rate for the ammonia stripping operation is 10–60 °C / h, for example, it can be 10 °C / h, 20 °C / h, 35 °C / h, 50 °C / h, 60 °C / h, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0040] The heating endpoint for the ammonia stripping operation is 85–99°C, for example, it can be 85°C, 88°C, 91°C, 95°C, 99°C, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0041] The ammonia stripping operation is carried out in a stirring process with no limit on the stirring speed or the time of the ammonia stripping operation. The final precursor is a powder, and the components of the powder are uniformly mixed and distributed.

[0042] In step (3), the binder may be one or more of water, silica sol, aluminosilicate sol, aluminum sol, polyethylene glycol, polyvinyl alcohol, cellulose, guar gum, guar gum powder, gum arabic powder, starch, nitric acid, glycerin, and corn dextrin.

[0043] The mass ratio of the amount of binder added to the amount of precursor is 0.01 to 0.1, for example, it can be 0.01, 0.03, 0.05, 0.08, 0.1, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0044] The mixing of the precursor and binder is carried out in a mixer or grinder, using standard industry operating methods, to achieve uniform dispersion of the precursor and binder aqueous solution, resulting in a viscous powder or slurry.

[0045] The method of coating the core is the rolling ball method, which can be achieved by using the industry's conventional rolling ball method. A constant temperature and humidity environment is preferred to ensure more uniform rolling ball quality.

[0046] In step (4), the drying operation is generally carried out in an oven or belt desiccant. Other drying equipment commonly used in other industries can also be used without any particular restrictions.

[0047] The drying temperature is 80–180°C, for example, 80°C, 100°C, 120°C, 150°C, 180°C, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable. The specific drying temperature should ensure that a large amount of moisture evaporates from the spheres during the drying process without significant migration and redistribution of active components.

[0048] The roasting operation is generally carried out in a muffle furnace, converter kiln or pusher kiln. Roasting equipment commonly used in other industries can also be used without any special restrictions.

[0049] The calcination temperature is 200–650°C, such as 200°C, 300°C, 400°C, 520°C, 650°C, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable. The specific calcination temperature should ensure that carbon and nitrogen impurities in the catalyst decompose and escape from the catalyst.

[0050] The present invention also provides the application of the above catalyst in the dehydrogenation cyclization of diol compounds to prepare lactones.

[0051] Preferably, the diol compound is any one or a combination of at least two of 1,3-propanediol, 1,4-butanediol, 1,4-pentanediol, 1,5-pentanediol, 1,4-hexanediol, 1,5-hexanediol, 1,6-hexanediol or diethylene glycol and their derivatives.

[0052] More preferably, the diol compound is any one or a combination of at least two of 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol or diethylene glycol and their derivatives.

[0053] More preferably, at least one hydrogen atom in the derivative that is attached to a carbon atom is substituted with an alkyl group, an ether bond, a hydroxyl group, a carbonyl group, a carboxyl group, an ester group, an amino group, an imino group, a nitro group, a nitroso group, a cyano group, an amide group, or an aryl group.

[0054] In the application of this invention, the dehydrogenation reaction process is as follows: the diol compound is mixed with hydrogen and vaporized, and then dehydrogenated and cyclized to generate the corresponding lactone.

[0055] Before the dehydrogenation reaction, the catalyst needs to be reduced. There are no special restrictions on the reduction conditions. The reduction is an exothermic reaction process, requiring the reduction temperature rise to be <20℃ to avoid catalyst sintering. After reduction, the copper species in the catalyst exist in the form of elemental copper.

[0056] Preferably, the temperature of the dehydrogenation reaction is 180 to 350°C, for example, it can be 180°C, 230°C, 280°C, 310°C, 350°C, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable. The specific temperature setting should ensure that the glycol and hydrogen are in a gaseous state in the reactor after being mixed and fed.

[0057] Preferably, the volume hourly space velocity (VHSV) of the diol feedstock for the dehydrogenation reaction is 0.01–2 h⁻¹. -1 For example, it could be 0.01h -1 0.05h -1 0.1h -1 1h -1 2h -1 This applies to, but is not limited to, the listed values; other unlisted values ​​within this range also apply.

[0058] Preferably, the dehydrogenation reaction is a hydrogen-induced reaction, and the molar ratio of hydrogen to alcohol is (1-30):1, for example, it can be 1:1, 5:1, 10:1, 20:1, 30:1, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0059] Preferably, the pressure of the dehydrogenation reaction is 0.01 to 1 MPaG, for example, 0.01 MPaG, 0.1 MPaG, 0.3 MPaG, 0.5 MPaG, 1 MPaG, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0060] The beneficial effects of this invention are as follows:

[0061] The coated catalyst prepared by this invention significantly reduces the amount of non-ferrous metals used, thereby substantially reducing the cost of catalyst raw materials. In some application examples, the coated catalyst prepared by the spherical molding process of this invention reduces the production cost by more than 50% compared to the traditional cylindrical catalyst.

[0062] Due to the presence of the inert ceramic ball core in the catalyst of this invention, the compressive strength of the catalyst is greatly improved. The alumina in the surface coating interacts with the alumina in the core ceramic ball during the catalyst calcination process, so that the coating is tightly bonded to the core. In some application examples, the allowable catalyst loading height is >10m, and the catalyst does not crack or break.

[0063] Both dehydration and hydrogenolysis side reactions require the catalytic action of acidic active sites. Introducing alumina into the catalyst improves the bonding between the coating layer and the core, while also introducing acidic sites. To mitigate its adverse effects, the strongly basic promoter cesium is introduced into the catalyst. The introduction of cesium strongly suppresses the dehydration side reaction and improves the selectivity of the dehydrogenation main product, lactone. Chromium, a dehydrogenation promoter, is also introduced into the catalyst. Chromium, in synergy with copper, strongly suppresses the hydrogenolysis side reaction and further enhances the dehydrogenation selectivity.

[0064] Under the same composition, the coated catalyst prepared by the spherical molding process of this invention has advantages over traditional cylindrical catalysts in terms of lower wear, less dust, and less breakage during production, transportation, and filling, making it more friendly to filling workers and the environment. Because of its uniform porosity after filling and fewer bridging and broken particles, the catalyst of this invention is particularly suitable for near-atmospheric pressure reaction conditions. In some application examples of the dehydrogenation of 1,4-butanediol to prepare γ-butyrolactone, the reaction tube inner diameter was 50 mm, the catalyst filling height was 5 m, and the volume hourly space velocity was 0.12 h⁻¹. -1 With a hydrogen-to-ethanol ratio of 13, a reaction pressure of 101 kPaG, and a reaction temperature of 240℃, the bed pressure drop was measured to be only 7 kPa, and the bed cold point was only 228℃. Detailed Implementation

[0065] To facilitate understanding of the present invention, the following description, in conjunction with embodiments, will further illustrate the invention. It should be understood that the following embodiments are merely for a better understanding of the invention and do not imply that the invention is limited to these embodiments.

[0066] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. Locational terms such as top and bottom, mentioned or possibly used in this specification, are defined relative to construction and are relative concepts, and therefore may vary depending on their location and usage.

[0067] Main raw material sources

[0068] Basic copper carbonate, copper nitrate trihydrate, copper hydroxide, copper acetate, cesium carbonate, cesium nitrate, cesium hydroxide, cesium acetate, ammonium chromate, chromium nitrate nonahydrate, chromium trioxide, chromium acetate, ammonia, tetraethyl silicate, fumed SiO2, aluminum nitrate nonahydrate, aluminum hydroxide, guar gum, and nitric acid were purchased from Aladdin Reagent (Shanghai) Co., Ltd. Silica sol was purchased from Shandong Kehan ​​Silicon Products Co., Ltd., aluminum sol from Suzhou Baird New Material Technology Co., Ltd., boehmite from Shandong Yuneng Technology Co., Ltd., ceramic balls from Jiangxi Anfa Environmental Protection New Material Co., Ltd., hydrogen from Air Liquide, and 1,4-butanediol from Wanhua Chemical.

[0069] Analysis method:

[0070] The composition of the products was analyzed by gas chromatography, and the conversion and selectivity of the diols were calculated by the area method: Instrument model: Agilent 8890; Column: HP-Innowax (30m×0.25mm×0.25μm); Injection volume: 0.5μL; Vaporization chamber temperature: 220℃; Initial column temperature: 50℃; Initial waiting time: 2 min; Then, the temperature was increased to 80℃ at a rate of 5℃ / min, and then increased to 260℃ at a rate of 15℃ / min, and held for 10 min; The carrier gas was high-purity nitrogen, with a split ratio of 30:1 and a split flow rate of 30 mL / min; The detector was a flame ionization detector, with a temperature of 260℃, an air flow rate of 400 mL / min, a hydrogen flow rate of 30 mL / min, and a make-up gas flow rate of 25 mL / min.

[0071] Example

[0072] Example 1

[0073] (1) 12.15g of copper nitrate trihydrate, 0.07g of cesium nitrate and 1.60g of chromium nitrate nonahydrate were added to 60g of 50% ammonia water to dissolve and disperse to obtain mixed solution X1. The dissolution and dispersion temperature was 25℃.

[0074] (2) Add 20.00 g of 20% silica sol and 305.17 g of 30% aluminum sol to the mixed solution X1, and then heat to 85℃ at 10℃ / h to evaporate ammonia to obtain precursor Z1;

[0075] (3) Take 100g of precursor Z1 and mix it with guar gum solution as binder. The amount of guar gum is 5g, and a sticky solid powder is obtained. Then roll it to coat the core of an alumina ceramic ball with a diameter of 2mm, a thermal conductivity of 28W / (m·K) and a water absorption rate of 5%, with a coating thickness of ~3mm.

[0076] (4) The coated product is dried at 180°C and then calcined at 650°C to obtain the coated catalyst product.

[0077] The catalyst coating layer prepared in this embodiment has the following composition: 4% CuO-4% SiO2-0.05% Cs2O-0.4% CrO3-91.55% Al2O3.

[0078] Example 2

[0079] (1) 60.74 g of copper nitrate trihydrate, 6.92 g of cesium nitrate, and 40.02 g of chromium nitrate nonahydrate were added to 370 g of 50% ammonia water to dissolve and disperse to obtain mixed solution X2. The dissolution and dispersion temperature was 25℃.

[0080] (2) Add 100.00g of 20% silica sol and 150.00g of 30% aluminum sol to the mixed solution X2, and then heat to 95℃ at 60℃ / h to evaporate ammonia to obtain precursor Z2;

[0081] (3) Take 100g of precursor Z2 and mix it with guar gum solution as binder. The amount of guar gum is 5g, and a sticky solid powder is obtained. Then, roll it onto the core of an alumina ceramic ball with a diameter of 5mm, a thermal conductivity of 30W / (m·K) and a water absorption rate of 5%, and the coating thickness is ~0.5mm.

[0082] (4) The coated product is dried at 80°C and then calcined at 650°C to obtain the coated catalyst product.

[0083] The catalyst coating layer prepared in this embodiment has a composition of 20% CuO-20% SiO2-5% Cs2O-10% CrO3-45% Al2O3.

[0084] Example 3

[0085] (1) Add 7.13g of basic copper carbonate, 0.12g of cesium carbonate and 0.76g of ammonium chromate to 840g of 20% ammonia water to dissolve and disperse to obtain mixed solution X3. The dissolution and dispersion temperature is 10℃.

[0086] (2) Add 15.00 g of gaseous SiO2 and 584.26 g of aluminum nitrate nonahydrate to the mixed solution X3, and then heat to 90 °C at 25 °C / h to evaporate ammonia to obtain precursor Z3;

[0087] (3) Take 100g of precursor Z3 and mix it with a 3% nitric acid solution of boehmite as a binder. The amount of boehmite used is 10g, and a sticky solid powder is obtained. Then, roll it onto the core of a silica-alumina ceramic ball with a diameter of 3mm, a thermal conductivity of 18W / (m·K), and a water absorption rate of 16%. The mass ratio of silica to alumina in the core is 0.06, and the coating thickness is ~2mm.

[0088] (4) The coated product is dried at 120°C and then calcined at 550°C to obtain the coated catalyst product.

[0089] The catalyst coating layer prepared in this embodiment has the following composition: 5% CuO-15% SiO2-0.1% Cs2O-0.5% CrO3-79.4% Al2O3.

[0090] Example 4

[0091] (1) Add 21.40g of basic copper carbonate, 1.16g of cesium carbonate and 2.28g of ammonium chromate to 850g of 20% ammonia water to dissolve and disperse to obtain mixed solution X4. The dissolution and dispersion temperature is 10℃.

[0092] (2) Add 10.00 g of gaseous SiO2 and 533.48 g of aluminum nitrate nonahydrate to the mixed solution X4, and then heat to 90 °C at 25 °C / h to evaporate ammonia to obtain precursor Z4;

[0093] (3) Take 100g of precursor Z4 and mix it with a 3% nitric acid solution of boehmite as a binder. The amount of boehmite used is 10g, and a sticky solid powder is obtained. Then, roll it onto the core of a silica-alumina ceramic ball with a diameter of 3mm, a thermal conductivity of 18W / (m·K), and a water absorption rate of 16%. The mass ratio of silica to alumina in the core is 0.06, and the coating thickness is ~2mm.

[0094] (4) The coated product is dried at 120°C and then calcined at 550°C to obtain the coated catalyst product.

[0095] The catalyst coating layer prepared in this embodiment has the following composition: 15% CuO-10% SiO2-1% Cs2O-1.5% CrO3-72.5% Al2O3.

[0096] Example 5

[0097] (1) Add 14.26g of basic copper carbonate, 3.47g of cesium carbonate and 4.56g of ammonium chromate to 880g of 20% ammonia water to dissolve and disperse to obtain mixed solution X5. The dissolution and dispersion temperature is 10℃.

[0098] (2) Add 5.00 g of gaseous SiO2 and 581.31 g of aluminum nitrate nonahydrate to the mixed solution X5, and then heat to 90 °C at 25 °C / h to evaporate ammonia to obtain precursor Z5;

[0099] (3) Take 100g of precursor Z5 and mix it with a 3% nitric acid solution of boehmite as a binder. The amount of boehmite used is 10g, and a sticky solid powder is obtained. Then, roll it onto the core of a silica-alumina ceramic ball with a diameter of 3mm, a thermal conductivity of 18W / (m·K), and a water absorption rate of 16%. The mass ratio of silica to alumina in the core is 0.06, and the coating thickness is ~2mm.

[0100] (4) The coated product is dried at 120°C and then calcined at 550°C to obtain the coated catalyst product.

[0101] The catalyst coating layer prepared in this embodiment has a composition of 10% CuO-5% SiO2-3% Cs2O-3% CrO3-79% Al2O3.

[0102] Example 6

[0103] (1) Add 18.40g of copper hydroxide, 1.06g of cesium hydroxide and 1.50g of chromium trioxide to 610g of 28% ammonia water to dissolve and disperse to obtain mixed solution X6. The dissolution and dispersion temperature is 50℃.

[0104] (2) Add 34.68 g of tetraethyl silicate and 110.93 g of aluminum hydroxide to the mixed solution X6, and then heat the solution to 92°C at 60°C / h to evaporate ammonia to obtain the precursor Z6;

[0105] (3) Take 100g of precursor Z6 and mix it with 5% nitric acid solution as binder. The amount of nitric acid is 1g, and a sticky solid powder is obtained. Then, roll it onto the core of a silica-alumina ceramic ball with a diameter of 4mm, a thermal conductivity of 25W / (m·K), and a water absorption rate of 9%. The mass ratio of silica to alumina in the core is 0.03, and the coating thickness is ~1.5mm.

[0106] (4) The coated product is dried at 100°C and then calcined at 600°C to obtain the coated catalyst product.

[0107] The catalyst coating layer prepared in this embodiment has the following composition: 15% CuO-10% SiO2-1% Cs2O-1.5% CrO3-72.5% Al2O3.

[0108] Example 7

[0109] (1) Add 34.25g of copper acetate, 1.36g of cesium acetate and 3.44g of chromium acetate to 610g of 28% ammonia water to dissolve and disperse to obtain mixed solution X7. The dissolution and dispersion temperature is 50℃.

[0110] (2) Add 34.68 g of tetraethyl silicate and 110.93 g of aluminum hydroxide to the mixed solution X7, and then heat to 92 °C at 20 °C / h to evaporate ammonia to obtain precursor Z7;

[0111] (3) Take 100g of precursor Z7 and mix it with 5% nitric acid solution as binder. The amount of nitric acid is 1g, and a sticky solid powder is obtained. Then, roll it onto the core of a silica-alumina ceramic ball with a diameter of 4mm, a thermal conductivity of 10W / (m·K), and a water absorption rate of 17%. The mass ratio of silica to alumina in the core is 0.08, and the coating thickness is ~1.5mm.

[0112] (4) The coated product is dried at 100°C and then calcined at 600°C to obtain the coated catalyst product.

[0113] The catalyst coating layer prepared in this embodiment has the following composition: 15% CuO-10% SiO2-1% Cs2O-1.5% CrO3-72.5% Al2O3.

[0114] Example 8

[0115] (1) Add 34.25g of copper acetate, 1.16g of cesium carbonate and 1.50g of chromium trioxide to 1300g of 10% ammonia water to dissolve and disperse to obtain mixed solution X8. The dissolution and dispersion temperature is 60℃.

[0116] (2) Add 50.00g of 20% silica sol and 110.93g of aluminum hydroxide to the mixed solution X8, and then heat to 92℃ at 40℃ / h to evaporate ammonia to obtain precursor Z8;

[0117] (3) Take 100g of precursor Z8, mix it with binder guar gum powder and 20% silica sol, the amount of guar gum powder is 2.00g and the amount of SiO2 is 3.00g, to obtain a sticky solid powder; then roll it to coat the core of a silica alumina ceramic ball with a diameter of 4mm, a thermal conductivity of 12W / (m·K) and a water absorption rate of 20%, the mass ratio of silica to alumina in the core is 0.10, and the coating thickness is ~1.5mm;

[0118] (4) The coated product is dried at 150°C and then calcined at 200°C to obtain the coated catalyst product.

[0119] The catalyst coating layer prepared in this embodiment has the following composition: 15% CuO-10% SiO2-1% Cs2O-1.5% CrO3-72.5% Al2O3.

[0120] Comparative Example

[0121] Comparative Example 1

[0122] (1) Add 21.40g of basic copper carbonate, 1.16g of cesium carbonate and 2.28g of ammonium chromate to 950g of 20% ammonia water to dissolve and disperse to obtain mixed solution X9. The dissolution and dispersion temperature is 10℃.

[0123] (2) Add 607.07 g of aluminum nitrate nonahydrate to the mixed solution X9, and then heat to 90 °C at 25 °C / h to evaporate ammonia to obtain precursor Z9;

[0124] (3) Take 100g of precursor Z9 and mix it with a 3% nitric acid solution of boehmite as a binder. The amount of boehmite used is 10g, and a sticky solid powder is obtained. Then, roll it onto the core of a silica-alumina ceramic ball with a diameter of 3mm, a thermal conductivity of 18W / (m·K), and a water absorption rate of 16%. The mass ratio of silica to alumina in the core is 0.06, and the coating thickness is ~2mm.

[0125] (4) The coated product is dried at 120°C and then calcined at 550°C to obtain the coated catalyst product.

[0126] The catalyst coating prepared in this comparative example does not contain silicon, and the composition of the catalyst coating is 15% CuO-1% Cs2O-1.5% CrO3-82.5% Al2O3.

[0127] Comparative Example 2

[0128] (1) Add 21.40g of basic copper carbonate and 2.28g of ammonium chromate to 860g of 20% ammonia water to dissolve and disperse to obtain a mixed solution X10, with a dissolution and dispersion temperature of 10℃;

[0129] (2) Add 10.00 g of gaseous SiO2 and 540.84 g of aluminum nitrate nonahydrate to the mixed solution X10, and then heat to 90 °C at 25 °C / h to evaporate ammonia to obtain precursor Z9;

[0130] (3) Take 100g of precursor Z10 and mix it with a 3% nitric acid solution of boehmite as a binder. The amount of boehmite used is 10g, and a sticky solid powder is obtained. Then, roll it onto the core of a silica-alumina ceramic ball with a diameter of 3mm, a thermal conductivity of 18W / (m·K), and a water absorption rate of 16%. The mass ratio of silica to alumina in the core is 0.06, and the coating thickness is ~2mm.

[0131] (4) The coated product is dried at 120°C and then calcined at 550°C to obtain the coated catalyst product.

[0132] The catalyst coating prepared in this comparative example does not contain cesium, and the catalyst coating composition is 15% CuO-10% SiO2-1.5% CrO3-73.5% Al2O3.

[0133] Comparative Example 3

[0134] (1) Add 21.40g of basic copper carbonate and 1.16g of cesium carbonate to 860g of 20% ammonia water to dissolve and disperse to obtain mixed solution X11. The dissolution and dispersion temperature is 10℃.

[0135] (2) Add 10.00 g of gaseous SiO2 and 544.52 g of aluminum nitrate nonahydrate to the mixed solution X11, and then heat to 90 °C at 25 °C / h to evaporate ammonia to obtain the precursor Z10;

[0136] (3) Take 100g of precursor Z11 and mix it with a 3% nitric acid solution of boehmite as a binder. The amount of boehmite used is 10g, and a sticky solid powder is obtained. Then, roll it onto the core of a silica-alumina ceramic ball with a diameter of 3mm, a thermal conductivity of 18W / (m·K), and a water absorption rate of 16%. The mass ratio of silica to alumina in the core is 0.06, and the coating thickness is ~2mm.

[0137] (4) The coated product is dried at 120°C and then calcined at 550°C to obtain the coated catalyst product.

[0138] The catalyst coating prepared in this comparative example does not contain chromium, and the catalyst coating composition is 15% CuO-10% SiO2-1% Cs2O-74% Al2O3.

[0139] Catalyst performance testing:

[0140] Take 50g of the dehydrogenation catalyst prepared in the above examples and comparative examples, and fill it centrally into a stainless steel reaction tube with an inner diameter of 30mm and a length of 800cm. The reaction tube is filled with inert quartz sand packing material at the top and bottom. First, dry it at 160℃ for 2h under a nitrogen atmosphere and a pressure of 0.1MPaG; then switch to a hydrogen atmosphere for reduction, gradually increasing the hydrogen concentration from 0.5% to 100% and the bed temperature from 160℃ to 250℃. Observe the exothermic reaction of reduction and control the reduction temperature rise to <20℃. After 48h of reduction, start feeding.

[0141] Using 1,4-butanediol as the reaction substrate and a hydrogen / alcohol ratio of 10 (molar ratio), the results are shown in Table 1.

[0142] Table 1

[0143]

[0144]

[0145] It is readily understood that the above embodiments are merely illustrative examples for clear explanation and do not imply that the invention is limited thereto. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A dehydrogenation catalyst characterized in that: the catalyst is a coated type comprising two parts of a core and a coating layer; the core is a porous inert porcelain ball, and the coating layer is a mixture containing copper, silicon, aluminum, cesium and chromium elements; the porous inert porcelain ball is a mixture of inert alumina and silica or inert alumina, and the mass ratio of the alumina and the silica is 0-1; the coating layer of the catalyst comprises 4-20 wt% of copper oxide, 4-20 wt% of silicon oxide, 0.05-5 wt% of cesium oxide, 0.4-10 wt% of chromium oxide calculated as chromium trioxide and 45-91.55 wt% of aluminum oxide based on the coating layer; and the thickness of the coating layer is 0.5-3 mm.

2. The catalyst according to claim 1, wherein the coating layer comprises 5-15 wt% of copper oxide, 5-15 wt% of silicon oxide, 0.1-3 wt% of cesium oxide, 0.5-3 wt% of chromium trioxide and 64-89.4 wt% of aluminum oxide based on the coating layer.

3. The catalyst according to claim 1 or 2, wherein the diameter of the porous inert porcelain ball of the core is 2-5 mm.

4. The catalyst according to any one of claims 1-3, wherein the water absorption of the porous inert porcelain ball of the core is 5-20% based on the mass of the core; and the thermal conductivity of the porous inert porcelain ball of the core is 10-30 W / (m·K).

5. A preparation method of the catalyst according to any one of claims 1-4, comprising the following steps: (1) dissolving and dispersing a copper source, a cesium source, a chromium source or a solution thereof in ammonia water to obtain a mixed solution X; (2) adding a silicon source and an aluminum source to the mixed solution X, and then heating and evaporating ammonia to obtain a precursor; (3) mixing the precursor and a binder, and coating on the core; and (4) drying and calcining the coated product to obtain a coated catalyst finished product.

2. The catalyst of claim 1, wherein:

6. The preparation method according to claim 5, wherein in step (1), the copper source is one or more of copper nitrate, copper carbonate, basic copper carbonate, copper hydroxide, copper formate, copper acetate, copper oxalate, copper citrate, copper oxide, cuprous oxide and copper powder; the cesium source is one or more of cesium nitrate, cesium carbonate, cesium hydroxide, cesium formate, cesium acetate, cesium oxalate, cesium citrate and cesium oxide; and the chromium source is one or more of chromium nitrate, chromium carbonate, chromium hydroxide, chromium formate, chromium acetate, chromium oxalate, chromium citrate, chromium trioxide, chromium dioxide, dichromium trioxide, chromate and dichromate.

3. The catalyst of claim 1, wherein:

7. The preparation method according to claim 5 or 6, wherein in step (1), the concentration of the ammonia water is 10-50 wt%; and the dissolving and dispersing temperature is 10-60℃.

4. The catalyst of claim 3, wherein:

8. The preparation method according to any one of claims 5-7, wherein in step (2), the silicon source is one or more of silicon dioxide, silica sol, silica-alumina sol, tetramethyl silicate and tetraethyl silicate; and the aluminum source is one or more of aluminum nitrate, aluminum carbonate, aluminum hydroxide, met aluminic acid, met aluminic acid salt, aluminum formate, aluminum acetate, aluminum oxalate, aluminum citrate, alcohol aluminum, alkyl aluminum, hydrated aluminum oxide, aluminum oxide, aluminum powder, silica-alumina sol and aluminum sol.

9. The preparation method according to any one of claims 5-8, wherein in step (2), the heating rate is 10-60℃ / h, and the final temperature of the heating and ammonia evaporation is 85-99℃.

10. The preparation method according to any one of claims 5-9, wherein in step (3), the binder is one or more of water, silica sol, silica-alumina sol, aluminum sol, polyethylene glycol, polyvinyl alcohol, cellulose, guar gum, sesbania powder, gum arabic powder, starch, nitric acid, glycerol and corn dextrin. ​ ​ ​ ​ 6. The preparation method according to claim 5, characterized in that, ​ 7. The preparation method according to claim 5, characterized in that, ​ ​ 8. The preparation method according to claim 5, characterized in that, ​ 9. The preparation method according to claim 5, characterized in that, ​ 10. The preparation method of claim 5, wherein ​ 11. The method of claim 10, wherein, In step (3), the mass ratio of the binder addition amount to the precursor amount is 0.01-0.

1.

12. The method of claim 5, wherein, In step (4), the drying temperature is 80-180℃, and the calcination temperature is 200-650℃.

13. Use of the catalyst according to any one of claims 1-4 in the dehydrocyclization of a diol compound to prepare a lactone.

14. Use according to claim 13, characterized in that, The diol compound includes any one of 1,3-propanediol, 1,4-butanediol, 1,4-pentanediol, 1,5-pentanediol, 1,4-hexanediol, 1,5-hexanediol, 1,6-hexanediol, or diethylene glycol, or a combination of at least two thereof; In the derivative, at least one hydrogen atom connected to carbon is substituted by an alkyl group, an ether bond, a hydroxyl group, a carbonyl group, a carboxyl group, an ester group, an amino group, an imino group, a nitro group, a nitroso group, a cyano group, an amide group, or an aryl group.

15. Use according to claim 13 or 14, characterized in that, The diol compound is mixed with hydrogen and vaporized to undergo dehydrocyclization to generate a corresponding lactone.

16. The use according to claim 15, characterized in that, The dehydrogenation reaction temperature is 180-350℃; The volume space velocity of the dehydrogenation reaction is 0.01-2 h -1 ; The dehydrogenation reaction is a hydrogenation reaction, and the hydrogen / alcohol molar ratio is (1-30):1; The dehydrogenation reaction pressure is 0.01-1 MPaG.

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