CN105056976B - Preparation method of vulcanized zirconium dioxide serving as solid acid catalyst and having high specific surface area - Google Patents

Abstract

The invention relates to a preparation method of a solid acid catalyst sulfurized zirconium dioxide with a high specific surface area, and the invention relates to a preparation method of a solid acid catalyst sulfurized zirconium dioxide. The invention aims to solve the problems that the existing sulfide zirconia preparation method is complicated, the preparation time is long, and the specific surface area of the prepared sulfide zirconia is small. The method comprises the following steps: 1. preparing zirconium hydroxide; 2. preparing powdery solid; 3. calcining to obtain sulfide zirconium dioxide, a solid acid catalyst with a high specific surface area. The invention is used for the preparation method of solid acid catalyst sulfurized zirconium dioxide with high specific surface area.

Description

Preparation of a solid acid catalyst sulfurized zirconia with high specific surface area method

technical field

The invention relates to a preparation method of solid acid catalyst sulfurized zirconium dioxide.

Background technique

Organic reactions such as isomerization of hydrocarbons play an important role in the petroleum industry and directly affect the development of the national economy. Usually these reactions can only be carried out under strong acid conditions. However, the liquid acid catalyst used in the reaction can promote the corrosion of the reaction unit, is not easy to separate from the reaction product, pollutes the environment, and has certain dangers. Therefore, the use of solid acid catalysts to replace liquid acid catalysts has a good development prospect, because solid acid catalysts can well solve the problems of difficult separation of liquid acid catalysts, environmental pollution, and corrosion of equipment. Recently, a large number of literatures have reported the preparation and application of solid acid catalysts such as zeolite molecular sieves, ion exchange resins, and metal oxides.

Among the solid ^acid catalysts, sulfurized zirconium _{dioxide (} SO ₄ ^2- /ZrO ₂ ) has attracted extensive attention from researchers because of its special surface acid properties , it has a good application prospect in many industrial important reactions. On the other hand, the catalytic activity of a catalyst is related to its specific surface area, and a higher specific surface area can provide more catalytically active sites. So the solid acid catalyst sulfurized zirconia (SO ₄ ^2- /ZrO ₂ ) with high specific surface area is a kind of catalyst with good application prospect.

Although a large number of documents and materials have reported the preparation method of sulfide zirconium dioxide (SO ₄ ^2- /ZrO ₂ ), that is, using the sol-gel method, this preparation method is complicated and takes a long time, and the required time is 72h~ 82h, and the specific surface area of the obtained sulfide zirconium dioxide (SO ₄ ^2- /ZrO ₂ ) is small, that is, the specific surface area is generally 70m ² /g-100m ² /g. So far, there are no literature reports that can increase the specific surface area and simplify the preparation method.

Contents of the invention

The present invention aims to solve the problems that the existing sulfide zirconia preparation method is complex, the preparation time is long, and the prepared sulfide zirconia has a small specific surface area, and a solid acid catalyst sulfide zirconia with a high specific surface area is provided. Preparation.

One, prepare the hydroxide of zirconium:

At room temperature, ZrOCl ₂ 8H ₂ O was mixed with deionized water and stirred to dissolve to obtain ZrOCl ₂ solution, which was weighed according to the molar ratio of N element in ammonia water to Zr element in ZrOCl ₂ 8H ₂ O was 5.5:1 Take ammonia water, then add the weighed ammonia water dropwise into the _ZrOCl solution at room temperature and under stirring conditions to obtain a mixture. Filter the precipitate, wash the precipitate with deionized water until there is no chloride ion in the washing liquid, and obtain the washed precipitate, and finally place the washed precipitate in an oven at a temperature of 80°C to 100°C, and dry it for 12h to 24h , to obtain the hydroxide of zirconium;

The volume ratio of the mass of ZrOCl ₂ ·8H ₂ O to deionized water is 1g:7.7580mL;

2. Preparation of powdery solid:

Weighing zirconium hydroxide and solid ammonium sulfate, at room temperature, placing the weighed zirconium hydroxide and solid ammonium sulfate in a mortar, mixing evenly and grinding to obtain a white powdery solid;

The mol ratio of the hydroxide of described zirconium to solid ammonium sulfate 1:(4～8);

3. Calcination:

Put the white powdery solid in a muffle furnace, raise the temperature of the muffle furnace to 600°C-750°C at a heating rate of 5°C/min, and then calcinate it for 5 hours at a temperature of 600°C-750°C to obtain Solid acid catalyst SO ₄ ^2- /ZrO ₂ , that is, a solid acid catalyst with high specific surface area sulfurized zirconia.

The beneficial effects of the present invention are: 1. The preparation of sulfide zirconium dioxide (SO ₄ ^2- /ZrO ₂ ) is simplified from the complex sol-gel method to the solid phase grinding method, that is, there is no solution involved in the preparation process, which can simplify During the preparation process, the preparation time is reduced from 72h to 82h to 50h to 55h.

2. The specific surface area of sulfide zirconia (SO ₄ ^2- /ZrO ₂ ) prepared by solid phase grinding method is larger than that of sulfide zirconia (SO ₄ ^2- /ZrO ₂ ) prepared by sol-gel method, and the surface area is the highest. It reaches 153m ² /g, while the specific surface area of sulfide zirconium dioxide (SO ₄ ^2- /ZrO ₂ ) prepared by the traditional method is only 87m ² /g. The larger specific surface area can provide more catalytic active sites for the reaction.

Description of drawings

Fig. 1 is that the calcination temperature is the same, and when the molar ratio is different, the sulfide zirconia prepared is at 77K N _The isotherm adsorption-desorption curve; a is the sulfide zirconia prepared by the traditional method in Example 4, and b is prepared in Example 2 The sulfide zirconia; c is the sulfide zirconia prepared in embodiment one; d is the sulfide zirconia prepared in embodiment three;

Fig. 2 is that the molar ratio is the same, when the calcination temperature is different, the sulfide zirconia prepared is at 77K N _The isotherm adsorption-desorption curve; e is the sulfide zirconia prepared in embodiment five; f is the sulfide prepared in embodiment six Zirconia; g is the sulfide zirconia prepared in Example 1; h is the sulfide zirconia prepared in Example 7; i is the sulfide zirconia prepared in Example 8.

detailed description

Specific embodiment one: the preparation method of a kind of solid acid catalyst sulfurized zirconium dioxide with high specific surface area described in this embodiment is completed according to the following steps:

One, prepare the hydroxide of zirconium:

At room temperature, ZrOCl ₂ 8H ₂ O was mixed with deionized water and stirred to dissolve to obtain ZrOCl ₂ solution, which was weighed according to the molar ratio of N element in ammonia water to Zr element in ZrOCl ₂ 8H ₂ O was 5.5:1 Take ammonia water, then add the weighed ammonia water dropwise into the _ZrOCl solution at room temperature and under stirring conditions to obtain a mixture. Filter the precipitate, wash the precipitate with deionized water until there is no chloride ion in the washing liquid, and obtain the washed precipitate, and finally place the washed precipitate in an oven at a temperature of 80°C to 100°C, and dry it for 12h to 24h , to obtain the hydroxide of zirconium;

The volume ratio of the mass of ZrOCl ₂ ·8H ₂ O to deionized water is 1g:7.7580mL;

2. Preparation of powdery solid:

Weighing zirconium hydroxide and solid ammonium sulfate, at room temperature, placing the weighed zirconium hydroxide and solid ammonium sulfate in a mortar, mixing evenly and grinding to obtain a white powdery solid;

The mol ratio of the hydroxide of described zirconium to solid ammonium sulfate 1:(4～8);

3. Calcination:

Put the white powdery solid in a muffle furnace, raise the temperature of the muffle furnace to 600°C-750°C at a heating rate of 5°C/min, and then calcinate it for 5 hours at a temperature of 600°C-750°C to obtain Solid acid catalyst SO ₄ ^2- /ZrO ₂ , that is, a solid acid catalyst with high specific surface area sulfurized zirconia.

In step ₁ of this specific embodiment, the precipitate is washed with deionized water until the AgNO3 solution is used to test that there is no chloride ion in the washing liquid.

Step 3 of this specific embodiment can remove impurity nitrogen, moisture and other impurities in the product.

Principle: Sulfide zirconia (SO ₄ ^2- /ZrO ₂ ) prepared by the grinding method and the traditional method, the sulfate radical interacts with the zirconium on the surface of the zirconia in a double-coordinated form, and the double-coordinated adsorption formed on the surface is Sulfurized zirconia (SO ₄ ^2- /ZrO ₂ ) provides solid acid sites, and the action of zirconium hydroxide and sulfate is different, which will make the prepared sulphurized zirconia (SO ₄ ^2- /ZrO ₂ ) The amount of sulfate group adsorbed by double coordination is different, so the acidity strength of the acid center and the specific surface area of the particles are also different. Therefore, the particle size and specific surface area of zirconium dioxide sulfide prepared by different preparation methods are different. At the same time, the change of calcination temperature will change the amount of sulfate group adsorbed by double coordination in sulfide zirconia (SO ₄ ^2- /ZrO ₂ ), so the acidity strength and particle size of sulfide zirconia after different calcination temperatures The specific surface area is also different.

The beneficial effects of this embodiment are: 1. The preparation of sulfide zirconium dioxide (SO ₄ ^2- /ZrO ₂ ) is simplified from the complicated sol-gel method to the solid phase grinding method, that is, there is no solution involved in the preparation process, which can The preparation process is simplified, and the preparation time is reduced from 72h to 82h to 50h to 55h.

2. The specific surface area of sulfide zirconia (SO ₄ ^2- /ZrO ₂ ) prepared by solid phase grinding method is larger than that of sulfide zirconia (SO ₄ ^2- /ZrO ₂ ) prepared by sol-gel method, and the surface area is the highest. It reaches 153m ² /g, while the specific surface area of sulfide zirconium dioxide (SO ₄ ^2- /ZrO ₂ ) prepared by the traditional method is only 87m ² /g. The larger specific surface area can provide more catalytic active sites for the reaction.

Specific embodiment 2: This embodiment differs from specific embodiment 1 in that in step 1, at room temperature, the mixture is first stirred for 1 h, and then aged for 24 h to obtain a precipitate. Others are the same as in the first embodiment.

Specific embodiment 3: The difference between this embodiment and specific embodiment 1 or 2 is that in step 1, the precipitate after washing is finally placed in an oven with a temperature of 100° C. and dried for 24 hours to obtain zirconium hydroxide . Others are the same as in the first or second embodiment.

Embodiment 4: The difference between this embodiment and one of Embodiments 1 to 3 is that the molar ratio of zirconium hydroxide and solid ammonium sulfate described in step 2 is 1:4. Others are the same as the specific embodiments 1 to 3.

Embodiment 5: This embodiment is different from Embodiment 1 to Embodiment 4 in that the molar ratio of zirconium hydroxide to solid ammonium sulfate described in step 2 is 1:6. Others are the same as the specific embodiments 1 to 4.

Embodiment 6: The difference between this embodiment and one of Embodiments 1 to 5 is that the molar ratio of zirconium hydroxide to solid ammonium sulfate described in step 2 is 1:8. Others are the same as those in Embodiments 1 to 5.

Embodiment 7: The difference between this embodiment and Embodiment 1 to 6 is that in step 3, the white powdery solid is placed in the muffle furnace, and the temperature of the muffle furnace is raised to 5° C./min at a heating rate of 600°C. Others are the same as those in Embodiments 1 to 6.

Embodiment 8: The difference between this embodiment and one of Embodiments 1 to 7 is that in step 3, calcining is carried out at a temperature of 600° C. for 5 hours. Others are the same as those in Embodiments 1 to 7.

Specific embodiment nine: the difference between this embodiment and one of the specific embodiments one to eight is: in step 3, the white powdery solid is placed in the muffle furnace, and the temperature of the muffle furnace is raised to 5° C./min at a heating rate of 650°C. Others are the same as those in Embodiments 1 to 8.

Embodiment 10: This embodiment is different from Embodiment 1 to Embodiment 9 in that: in step 3, the calcining is carried out for 5 hours at a temperature of 650°C. Others are the same as the specific embodiments 1 to 9.

Adopt the following examples to verify the beneficial effects of the present invention:

Embodiment one:

A kind of preparation method of the solid acid catalyst sulfurized zirconium dioxide with high specific surface area described in the present embodiment is completed according to the following steps:

One, prepare the hydroxide of zirconium:

At room temperature, mix 6.445g ZrOCl ₂ 8H ₂ O with 50mL deionized water and stir to dissolve to obtain a ZrOCl ₂ solution. The molar ratio of N element in ammonia water to Zr element in ZrOCl ₂ 8H ₂ O is 5.5:1 Weigh 7.205g of ammonia water with a mass percentage of ₂₆ %, then add the weighed ammonia water dropwise to the ZrOCl solution at room temperature and under stirring conditions to obtain a mixture, at room temperature, first stir the mixture for 1h, and then age After 24 hours, the precipitate was obtained, the precipitate was filtered, and the precipitate was washed with deionized water until there was no chloride ion in the washing liquid to obtain the washed precipitate, and finally the washed precipitate was placed in an oven with a temperature of 100°C. After drying for 24 hours, the hydroxide of zirconium is obtained;

2. Preparation of powdery solid:

Weigh 0.725g of zirconium hydroxide and 3.6113g of solid ammonium sulfate, place the weighed zirconium hydroxide and solid ammonium sulfate in a mortar at room temperature, mix well and grind, grind for 30min to obtain white powder shape solid;

3. Calcination:

Put the white powdery solid in a muffle furnace, raise the temperature of the muffle furnace to 600°C at a heating rate of 5°C/min, and then calcinate for 5 hours at a temperature of 600°C to obtain a solid acid catalyst SO ₄ ^{2 -} /ZrO ₂ , a solid acid catalyst sulfurized zirconia with a high specific surface area.

That is, the molar ratio of zirconium hydroxide to solid ammonium sulfate described in step 2 of this embodiment is 1:6.

Embodiment 2: The difference between this embodiment and Embodiment 1 is that in step 2, 0.725g of zirconium hydroxide and 2.4075g of solid ammonium sulfate are weighed. Others are the same as in Embodiment 1.

That is, the molar ratio of zirconium hydroxide and solid ammonium sulfate described in step 2 of this embodiment is 1:4.

Embodiment three: the difference between this embodiment and embodiment one is: in the step two, 0.725g of zirconium hydroxide and 4.8151g of solid ammonium sulfate are weighed. Others are the same as in Embodiment 1.

That is, the molar ratio of zirconium hydroxide to solid ammonium sulfate described in step 2 of this embodiment is 1:8.

Embodiment four: the comparative experiment of embodiment one to three, specifically carry out according to the following steps: 0.99g solid ammonium sulfate is dissolved in deionized water, obtains the ammonium sulfate solution that 15mL concentration is 0.5mol/L, then 1g zirconium The hydroxide was added to the ammonium sulfate solution with a concentration of 0.5mol/L, stirred at room temperature for 2 hours, and filtered to obtain a solid product. The solid product was placed in an oven at a temperature of 100°C and dried for 12 hours to obtain the dried product , put the dried product in a muffle furnace, raise the temperature of the muffle furnace to 600°C at a heating rate of 5°C/min, and then calcinate for 5 hours at a temperature of 600°C to obtain a solid prepared by the traditional method Acid catalyst SO ₄ ^2- /ZrO ₂ .

Embodiment 5: For comparative experiments, the difference between this embodiment and Embodiment 1 is that in step 3, the muffle furnace is heated to 450° C. at a heating rate of 5° C./min, and then at a temperature of 450° C., Calcined for 5h. Others are the same as in Embodiment 1.

Embodiment 6: For a comparative experiment, the difference between this embodiment and Embodiment 1 is that in step 3, the muffle furnace is heated to 550° C. at a heating rate of 5° C./min, and then at a temperature of 550° C., Calcined for 5h. Others are the same as in Embodiment 1.

Example 7: The difference between this example and Example 1 is that in step 3, the temperature of the muffle furnace was raised to 650° C. at a heating rate of 5° C./min, and then calcined at 650° C. for 5 hours. Others are the same as in Embodiment 1.

Embodiment 8: The difference between this embodiment and Embodiment 1 is that in step 3, the temperature of the muffle furnace is raised to 750° C. at a heating rate of 5° C./min, and then calcined for 5 hours at a temperature of 750° C. Others are the same as in Embodiment 1.

Table 1 The specific surface area and pore volume of SO ₄ ^2- /ZrO ₂ prepared by different methods

It can be seen from Table 1 that when the calcination temperature is 600°C, the specific surface area of sulfide zirconium dioxide (SO ₄ ^2- /ZrO ₂ ) first increases and then decreases with the increase of ammonium sulfate solid content. When the molar ratio of solid zirconium hydroxide and solid ammonium sulfate is 1:6, the specific surface area of the prepared sulfide zirconium dioxide (SO ₄ ^2- /ZrO ₂ ) is 124m ² /g, while the traditional method prepared The specific surface area of sulfide zirconium dioxide (SO ₄ ^2- /ZrO ₂ ) is 87m ² /g, so when the calcination temperature is 600°C, the molar ratio of ground zirconium hydroxide to solid ammonium sulfate is 1: The specific surface area of the sulfide zirconia (SO ₄ ^2- /ZrO ₂ ) prepared by the mixture of 6 is larger than that of the sulfide zirconia (SO ₄ ^2- /ZrO ₂ ) prepared by the traditional method. The molar ratio of solid zirconium hydroxide and solid ammonium sulfate is 1:6 for the grinding method.

Table 2 The specific surface area and pore volume of SO ₄ ^2- /ZrO ₂ prepared at different calcination temperatures in the grinding method

It can be seen from Table 2 that when the molar ratio of solid zirconium hydroxide and solid ammonium sulfate is 1:6, as the calcination temperature increases, the specific surface area of sulfide zirconium dioxide (SO ₄ ^2- /ZrO ₂ ) First increase and then decrease. When the calcining temperature is 650°C, the prepared zirconia sulfide (SO ₄ ^2- /ZrO ₂ ) has the largest specific surface area, so the calcining temperature selected for the grinding method is 650°C.

Fig. 1 is that the calcination temperature is the same, and when the molar ratio is different, the sulfide zirconia prepared is at 77K N _The isotherm adsorption-desorption curve; a is the sulfide zirconia prepared by the traditional method in Example 4, and b is prepared in Example 2 sulfide zirconia; c is the sulfide zirconia prepared in Example 1; d is the sulfide zirconia prepared in Example 3. It can be concluded from Fig. 1 that although the molar ratio of raw materials of zirconia sulfide (SO ₄ ^2- /ZrO ₂ ) prepared by solid phase grinding method is different, the N ₂ adsorption-desorption isotherm curves at 77K all have obvious hysteresis loops , is the type III adsorption-desorption curve.

Fig. 2 is that the molar ratio is the same, when the calcination temperature is different, the sulfide zirconia prepared is at 77K N _The isotherm adsorption-desorption curve; e is the sulfide zirconia prepared in embodiment five; f is the sulfide prepared in embodiment six Zirconia; g is the sulfide zirconia prepared in Example 1; h is the sulfide zirconia prepared in Example 7; i is the sulfide zirconia prepared in Example 8. It can be concluded from Fig. 2 that the sulfide zirconium dioxide (SO ₄ ^2- /ZrO ₂ ) prepared by the solid phase grinding method has obvious hysteresis loops in the N ₂ adsorption-desorption isotherm curves at 77K, although the calcination temperature is different. It is a type III adsorption-desorption curve.

Claims (2)

1. a kind of preparation method of the solid acid catalyst sulfurized zirconium dioxide with high specific surface area, it is characterized in that a kind of preparation method of the solid acid catalyst sulfurized zirconium dioxide with high specific surface area is finished according to the following steps: One, prepare the hydroxide of zirconium: At room temperature, ZrOCl ₂ 8H ₂ O was mixed with deionized water and stirred to dissolve to obtain ZrOCl ₂ solution, which was weighed according to the molar ratio of N element in ammonia water to Zr element in ZrOCl ₂ 8H ₂ O was 5.5:1 Take ammonia water, then add the weighed ammonia water dropwise into the _ZrOCl solution at room temperature and under stirring conditions to obtain a mixture. Filter the precipitate, wash the precipitate with deionized water until there is no chloride ion in the washing liquid, and obtain the washed precipitate, and finally place the washed precipitate in an oven at a temperature of 80°C to 100°C, and dry it for 12h to 24h , to obtain the hydroxide of zirconium; The volume ratio of the mass of ZrOCl ₂ ·8H ₂ O to deionized water is 1g:7.7580mL; 2. Preparation of powdery solid: Weighing zirconium hydroxide and solid ammonium sulfate, at room temperature, placing the weighed zirconium hydroxide and solid ammonium sulfate in a mortar, mixing evenly and grinding to obtain a white powdery solid; The mol ratio of the hydroxide of described zirconium and solid ammonium sulfate is 1:6; 3. Calcination: Put the white powdery solid in a muffle furnace, raise the temperature of the muffle furnace to 600°C at a heating rate of 5°C/min, and then calcinate for 5 hours at a temperature of 600°C to obtain a solid acid catalyst SO ₄ ^{2 -} /ZrO ₂ , a solid acid catalyst sulfurized zirconia with a high specific surface area. 2. a kind of preparation method with the solid acid catalyst sulfurized zirconium dioxide of high specific surface area according to claim 1, it is characterized in that in step 1, the precipitate after washing is placed in the oven of 100 ℃ at last, dry After 24h, the hydroxide of zirconium was obtained.