阅读说明：本技术 多孔氧化锆基固体酸催化剂及其制备方法和应用 (Porous zirconia-based solid acid catalyst and preparation method and application thereof ) 是由 王锐 阳雪 于 2018-05-31 设计创作，主要内容包括：本发明涉及固体酸催化剂领域,公开了一种多孔氧化锆基固体酸催化剂及其制备方法和应用。本发明的多孔氧化锆基固体酸催化剂的制备方法包括：1)将含有锆盐、铝盐、有机酸螯合剂和相分离诱导剂的溶液与氨水进行第一接触,得到第一接触后的产物；2)将步骤1)得到的第一接触后的产物进行水热溶剂处理后,得到处理后的产物；3)将步骤2)中得到的处理后的产物与硫酸进行第二接触后固液分离,并将固液分离得到的固体进行第一焙烧；4)将第一焙烧得到的产物与氯铂酸进行第三接触后进行第二焙烧。将本发明的多孔氧化锆基固体酸催化剂用于直链烷烃的加氢异构化反应,在相同的反应温度下,转化率和产物选择性更高,稳定性更好。(The invention relates to the field of solid acid catalysts, and discloses a porous zirconia-based solid acid catalyst, and a preparation method and application thereof. The preparation method of the porous zirconia-based solid acid catalyst comprises the following steps: 1) carrying out first contact on a solution containing a zirconium salt, an aluminum salt, an organic acid chelating agent and a phase separation inducer and ammonia water to obtain a product after the first contact; 2) carrying out hydrothermal solvent treatment on the first contacted product obtained in the step 1) to obtain a treated product; 3) carrying out solid-liquid separation after carrying out second contact on the treated product obtained in the step 2) and sulfuric acid, and carrying out first roasting on the solid obtained by the solid-liquid separation; 4) and carrying out third contact on the product obtained by the first roasting and chloroplatinic acid, and then carrying out second roasting. The porous zirconia-based solid acid catalyst is used for the hydroisomerization reaction of straight-chain alkane, and has higher conversion rate and product selectivity and better stability at the same reaction temperature.)

1. A method for producing a porous zirconia-based solid acid catalyst, characterized by comprising the steps of,

1) carrying out first contact on a solution containing a zirconium salt, an aluminum salt, an organic acid chelating agent and a phase separation inducer and ammonia water to obtain a product after the first contact;

2) Carrying out hydrothermal solvent treatment on the first contacted product obtained in the step 1) to obtain a treated product;

3) Carrying out solid-liquid separation after carrying out second contact on the treated product obtained in the step 2) and sulfuric acid, and carrying out first roasting on the solid obtained by the solid-liquid separation;

4) and carrying out third contact on the product obtained by the first roasting and chloroplatinic acid, and then carrying out second roasting.

2. The method of claim 1, wherein the zirconium salt is one or more of zirconium oxychloride, zirconium oxynitrate, and zirconium nitrate;

preferably, the aluminum salt is one or more of aluminum nitrate, aluminum chloride and aluminum sulfate;

Preferably, the organic acid chelating agent is one or more of citric acid, tartaric acid, oleic acid and gluconic acid;

Preferably, the phase separation inducer is one or more of polyoxyethylene, polyacrylic acid, polyethylene glycol, and polyethylene oxide.

3. the method according to claim 1, wherein the zirconium salt in terms of zirconium, the aluminum salt in terms of aluminum, the organic acid chelating agent, and the phase separation inducing agent are used in a molar ratio of 1: 0.01-2: 0.05-4: 0.00001-0.0001;

Preferably, the solvent in the solution containing the zirconium salt, the aluminum salt, the organic acid chelating agent and the surfactant is one or more of water, ethanol, ethylene glycol and glycerol;

Preferably, ammonia water is added dropwise to a solution containing a zirconium salt, an aluminum salt, an organic acid chelating agent, and a phase separation inducer;

Preferably, the concentration of the ammonia water is 2-7 mol/L;

Preferably, the ammonia water is used in an amount such that the pH value of the contacted product is 8-10.

4. the method of claim 1, wherein the conditions of the hydrothermal solvent treatment comprise: the temperature is 60-150 ℃, and the time is 6-36 hours;

Preferably, the solvent used in the hydrothermal solvent treatment is water or a mixed solvent of water and a water-soluble organic solvent.

5. The method of claim 1, wherein the method further comprises: a step of washing the resulting treated product before second contacting the resulting treated product with sulfuric acid.

6. The process of any one of claims 1 to 5, wherein the second contacting of the resulting treated product with sulfuric acid is carried out by impregnating the resulting treated product with a solution of sulfuric acid;

Preferably, the concentration of the sulfuric acid in the sulfuric acid solution is 0.5-1.5mol/L, and the amount of the sulfuric acid solution is 5-15mL relative to 1g of the treated product.

7. the method of any one of claims 1-5, wherein the conditions of the second contacting comprise: the temperature is 10-40 ℃, and the time is 0.2-4 hours;

preferably, the conditions of the first firing include: the temperature is 650 ℃ and 750 ℃ and the time is 2-4 hours.

8. The method according to any one of claims 1 to 5, wherein the third contacting of the first calcined product with chloroplatinic acid is carried out by impregnating the first calcined product with a solution of chloroplatinic acid;

Preferably, the concentration of chloroplatinic acid in the chloroplatinic acid solution is 0.01 to 0.1mol/L, and the amount of the chloroplatinic acid solution is 0.1 to 1mL relative to 1g of the product obtained by the first calcination.

9. The method of any of claims 1-5, wherein the conditions of the second firing comprise: the temperature is 400 ℃ and 500 ℃ and the time is 2-4 hours.

10. A porous zirconia-based solid acid catalyst prepared by the method of any one of claims 1 to 9.

11. use of the porous zirconia-based solid acid catalyst prepared by the method of any one of claims 1 to 9 in a hydroisomerization reaction of linear paraffins.

Technical Field

The invention relates to the field of solid acid catalysts, in particular to a porous zirconia-based solid acid catalyst and a preparation method and application thereof.

Background

With the increasing importance of the country on environmental protection, the quality specification of the motor gasoline product is higher and higher, and the limitation on the contents of aromatic hydrocarbon and olefin in the motor gasoline is stricter and stricter.

Isomerization of light naphtha produces an isomerate that is sulfur-free, aromatics-free, olefins-free, and can increase the light naphtha octane number by 10-20 units by using different light naphtha isomerization technologies and processing schemes, and the isomerate is an ideal clean gasoline blending component.

The isomerization of light paraffin is generally carried out under the hydrogen condition, and is a process for generating corresponding isoparaffin from normal paraffin.

₄ ^2- _{2 2}the present industrial catalyst is a bifunctional catalyst containing noble metal, and is mainly divided into three types according to the difference of carriers, namely an aluminum chloride type, a molecular sieve type and an oxide type (solid super acid). in the catalyst, a metal oxide type solid super acid catalytic material has the advantages of stronger acidity, higher thermal stability, easy phase separation with a reaction product, environmental friendliness, no corrosion to equipment, regeneration and the like, and particularly can catalyze alkane isomerization reaction at low temperature, SO the catalyst is regarded as the most promising isomerization catalyst and has wide application prospect.

Currently, the method commonly used for preparing Sulfated zirconia catalysts is a zirconium salt hydrolysis precipitation method, which is approximately Zr salt precipitation → Zr (OH) ₄ drying → dipping sulfate → drying roasting → dipping Pt drying roasting, for example, in the reports of Monocolic and Tetragonal High Surface Area sulfuric acid in hydrothermal synthesis, CO Adsorption and Catalysis solutions, and Journal of Catalysis 2001,198: 277) 285, the hydrothermal method is adopted for hydrothermal treatment at 150 ℃ for 2-20 hours, so as to prepare Sulfated ZrO ₂ with High specific Surface Area, and the product has High butane isomerization performance, but the ZrO ₂ prepared by the method is mainly Monoclinic phase, and has poor activity, conversion rate and product selectivity in isomerization reaction of C5-C6.

Disclosure of Invention

The porous zirconia-based solid acid catalyst is used for the hydroisomerization reaction of straight-chain paraffin, and has higher conversion rate and product selectivity and better stability at the same reaction temperature.

in order to accomplish the above object, according to one aspect of the present invention, there is provided a method for preparing a porous zirconia-based solid acid catalyst, the method comprising the steps of,

1) Carrying out first contact on a solution containing a zirconium salt, an aluminum salt, an organic acid chelating agent and a phase separation inducer and ammonia water to obtain a product after the first contact;

2) Carrying out hydrothermal solvent treatment on the first contacted product obtained in the step 1) to obtain a treated product;

3) Carrying out solid-liquid separation after carrying out second contact on the treated product obtained in the step 2) and sulfuric acid, and carrying out first roasting on the solid obtained by the solid-liquid separation;

4) and carrying out third contact on the product obtained by the first roasting and chloroplatinic acid, and then carrying out second roasting.

The second aspect of the present invention provides a porous zirconia-based solid acid catalyst prepared by the above-described preparation method.

The second aspect of the invention provides an application of the porous zirconia-based solid acid catalyst prepared by the preparation method in a hydroisomerization reaction of straight-chain paraffin.

According to the preparation method, a sol-gel method and a precipitation method are combined, and phase separation is introduced to obtain a porous structure. Compared with the catalyst prepared by the conventional precipitation method, the obtained catalyst is single tetragonal mesoporous zirconia, has high specific surface and large pore volume, can obtain a porous structure with larger pore volume compared with the conventional sol-gel method, and has the advantages of simple preparation, low cost and good catalytic performance. In addition, when the porous zirconia-based solid acid catalyst prepared by the preparation method is used for the hydroisomerization reaction of straight-chain paraffin, the conversion rate and the product selectivity are higher and the stability is better at the same reaction temperature.

drawings

Fig. 1 is a Scanning Electron Microscope (SEM) photograph of the porous zirconia-based solid acid catalyst prepared in example 1;

Fig. 2 is a Scanning Electron Microscope (SEM) photograph of the zirconia-based solid acid catalyst prepared in comparative example 2.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

according to a first aspect of the present invention, there is provided a method for producing a porous zirconia-based solid acid catalyst, comprising the steps of,

1) Carrying out first contact on a solution containing a zirconium salt, an aluminum salt, an organic acid chelating agent and a phase separation inducer and ammonia water to obtain a product after the first contact;

2) Carrying out hydrothermal solvent treatment on the first contacted product obtained in the step 1) to obtain a treated product;

3) Carrying out solid-liquid separation after carrying out second contact on the treated product obtained in the step 2) and sulfuric acid, and carrying out first roasting on the solid obtained by the solid-liquid separation;

4) And carrying out third contact on the product obtained by the first roasting and chloroplatinic acid, and then carrying out second roasting.

According to the present invention, the zirconium salt may be various existing zirconium-containing salts that can be used for preparing the porous zirconia-based solid acid catalyst, preferably one or more of zirconium oxychloride, zirconyl nitrate, and zirconium nitrate; more preferably zirconium oxychloride.

According to the present invention, the aluminum salt may be various existing aluminum-containing salts that can be used for preparing the porous zirconia-based solid acid catalyst, preferably one or more of aluminum nitrate, aluminum chloride, and aluminum sulfate; more preferably aluminum nitrate.

According to the present invention, the organic acid chelating agent may be one or more of citric acid, tartaric acid, oleic acid and gluconic acid; citric acid is preferred.

in the present invention, the activity of the resulting catalyst can be significantly improved by using a phase separation inducer. Preferably, the phase separation inducer may be one or more of polyoxyethylene, polyacrylic acid, polyethylene glycol, and polyethylene oxide; more preferably polyoxyethylene.

According to the present invention, preferably, the zirconium salt in terms of zirconium, the aluminum salt in terms of aluminum, the organic acid chelating agent, and the phase separation inducer are used in an amount of 1: 0.01-2: 0.05-4: 0.00001-0.0001; from the viewpoint of further improving the conversion, product selectivity and stability of the obtained porous zirconia-based solid acid catalyst, the amount of the zirconium salt in terms of zirconium, the aluminum salt in terms of aluminum, the organic acid chelating agent and the phase separation inducer is more preferably used in a molar ratio of 1: 0.04-0.5: 0.1-1: 0.00001 to 0.00005, more preferably 1: 0.05-0.25: 0.12-0.35: 0.00001-0.00003.

According to the present invention, the solvent in the solution containing the zirconium salt, the aluminum salt, the organic acid chelating agent, and the phase separation inducer may be any solvent that can dissolve the zirconium salt, the aluminum salt, the organic acid chelating agent, and the phase separation inducer without reacting with them, and preferably, the solvent in the solution containing the zirconium salt, the aluminum salt, the organic acid chelating agent, and the phase separation inducer is one or more of water, ethanol, ethylene glycol, and glycerol; more preferably, the solvent in the solution containing the zirconium salt, the aluminum salt, the organic acid chelating agent and the surfactant is water and/or ethanol.

the amount of the solvent used is not particularly limited as long as the zirconium salt, the aluminum salt, the organic acid chelating agent, and the phase separation inducer can be sufficiently dissolved. Preferably, the solvent is used in an amount of 100-1000mL, more preferably 200-750mL, relative to 1 mole of the zirconium salt in terms of zirconium.

According to the present invention, the solution containing the zirconium salt, the aluminum salt, the organic acid chelating agent, and the phase separation inducer is preferably contacted with the aqueous ammonia for the first time, and the aqueous ammonia is preferably added dropwise to the solution containing the zirconium salt, the aluminum salt, the organic acid chelating agent, and the phase separation inducer. Preferably, the concentration of the ammonia water is 2-7 mol/L.

In addition, the amount of the aqueous ammonia is preferably such that the pH of the product after contact is 8 to 10, and more preferably such that the pH of the product after contact is 8 to 9. In addition, the first contacting may be carried out at room temperature, for example, at 15 to 40 ℃.

According to the present invention, the conditions of the hydrothermal solvent treatment include: the temperature is 60-150 ℃, and the time is 6-36 hours; preferably, the conditions of the hydrothermal solvent treatment include: the temperature is 110-130 ℃ and the time is 12-24 hours.

The solvent used in the hydrothermal solvent treatment may be water or a mixed solvent of water and a water-soluble organic solvent. The water-soluble organic solvent is preferably one or more of ethanol, propanol and polyethylene glycol. The amount of the solvent used in the hydrothermal treatment may be selected according to the weight of the gel product, and preferably, the amount of the solvent is 30 to 150% by weight, more preferably 50 to 120% by weight, based on the weight of the gel product.

according to the present invention, preferably, the method further comprises: a step of washing the resulting treated product before second contacting the resulting treated product with sulfuric acid. The solvent for the washing may be, for example, water.

According to the present invention, the form of the second contact between the obtained treated product and sulfuric acid is not particularly limited, and for example, the obtained treated product may be contacted with a sulfuric acid solution. Preferably, the second contacting of the treated product obtained with sulfuric acid is carried out by impregnating the treated product obtained with a sulfuric acid solution. More preferably, the impregnation of the treated product with the sulfuric acid solution is carried out under stirring.

The concentration of sulfuric acid in the sulfuric acid solution may be, for example, 0.5 to 4mol/L, preferably 0.5 to 1.5mol/L, and more preferably 1 to 1.5 mol/L. The amount of the sulfuric acid solution to be used is 5 to 30mL, preferably 5 to 15mL, and more preferably 8 to 12mL, based on 1g of the treated product.

According to the present invention, preferably, the conditions of the second contacting include: the temperature is 10-40 ℃, and the time is more than 5 minutes; more preferably, the conditions of the second contacting include: the temperature is 15-40 deg.C, and the time is 0.5-2 hr.

according to the present invention, the treated product obtained is subjected to a second contact with sulfuric acid and then subjected to solid-liquid separation, which may be performed by filtration or centrifugation, for example. Preferably, after the solid-liquid separation, the solid obtained by the solid-liquid separation is washed and dried. The solvent for the washing may be, for example, water, and the drying may be, for example, drying at 100-120 ℃ to constant weight.

According to the present invention, preferably, the conditions of the first firing include: the temperature is 600 ℃ and 800 ℃, and the time is 1-6 hours; more preferably, the conditions of the first firing include: the temperature is 650 ℃ and 750 ℃ and the time is 2-4 hours. Further, it is preferable that the first baking is performed in an air atmosphere.

According to the present invention, after the solid obtained by the solid-liquid separation is subjected to the first calcination, the calcined product is subjected to the third contact with chloroplatinic acid to support Pt.

according to the present invention, the third contact mode between the product obtained by the first calcination and chloroplatinic acid is not particularly limited, and for example, the product obtained by the first calcination may be contacted with a chloroplatinic acid solution. Preferably, the third contacting of the product obtained by the first calcination with chloroplatinic acid is performed in such a manner that the product obtained by the first calcination is impregnated with a solution of chloroplatinic acid. The impregnation is preferably incipient wetness impregnation.

the concentration of chloroplatinic acid in the above-mentioned chloroplatinic acid solution may be, for example, 0.01 to 0.1mol/L, preferably 0.02 to 0.05 mol/L. The amount of the chloroplatinic acid solution to be used is 0.1 to 1mL, preferably 0.3 to 0.6mL, based on 1g of the product obtained by the first calcination.

According to the present invention, the third contact is preferably carried out at room temperature, and may be carried out at, for example, 10 to 40 ℃, and the contact time is not particularly limited, and may be, for example, until the solution is evaporated to dryness.

According to the present invention, preferably, the method further comprises a step of drying the product of the second contact before performing the second firing. The drying may be carried out, for example, at 80 to 120 ℃ for 12 to 24 hours.

according to the present invention, preferably, the conditions of the second firing include: the temperature is 400 ℃ and 600 ℃, and the time is 2-6 hours; more preferably, the conditions of the second firing include: the temperature is 400 ℃ and 500 ℃ and the time is 2-4 hours. Further, it is preferable that the second baking is performed in an air atmosphere.

According to the present invention, in the step (4), the Pt loading is preferably 0.05 to 2% by weight, more preferably 0.1 to 0.3% by weight.

According to a second aspect of the present invention, there is also provided a porous zirconia-based solid acid catalyst obtained by the above method.

the porous zirconia-based solid acid catalyst according to the present invention is a tetragonal phase, has a specific surface area of 170-400m ²/g and a pore volume of 0.16-0.4cm ³/g.

according to a third aspect of the present invention, the present invention also provides the use of the porous zirconia-based solid acid catalyst obtained by the above method in a hydroisomerization reaction of linear paraffins.

The porous zirconia-based solid acid catalyst has higher specific surface and pore volume, and has higher conversion rate and product selectivity and better stability when being used for the hydroisomerization reaction of straight-chain alkane at the same reaction temperature.

The present invention will be described in detail below by way of examples.

In the following examples and comparative examples, the scanning electron microscope used was FEI Company Nova NanoSEM 450 model;

Specific surface area and pore volume were determined by nitrogen adsorption on a specific surface analyzer, model tristar II 3020-M, available from Micromeritics;

The composition of the crystalline phases was determined by X-ray diffraction (XRD) using an instrument model D8 from Bruker;

The initial C6 conversion, C6 conversion, 2-DMB (2, 2-dimethylbutane) selectivity, and isomerization were measured for content by a gas chromatograph available from shimadzu corporation, japan, model GC-2014, and calculated by the following formulas.

Initial n-hexane C6 conversion ═ amount (amount of n-hexane initially consumed in the reaction for 40 minutes (mol/min))/(amount of n-hexane introduced in the reaction (mol/min)) × 100%

N-hexane C6 conversion ═ amount (amount of n-hexane consumed for 6 hours of reaction (mol/min))/(amount of n-hexane introduced for reaction (mol/min)) × 100%

2,2-DMB selectivity (amount of 2,2-DMB produced by the reaction (mol/min))/(amount of n-hexane consumed in the reaction (mol/min)) × 100%

The isomerization ratio was (amount of isomer produced by the reaction (mol/min))/(amount of n-hexane consumed in the reaction (mol/min)). times.100% (here, the isomerization products were isobutane, isopentane, 2-DMB, 2,3-DMB (2, 3-dimethylbutane), 2-MP (2-methylpentane), 3-MP (3-methylpentane))

In addition, commercially available products are used as the raw materials unless otherwise specified.