CN109513455B

CN109513455B - Epoxidation catalyst, method of making and method of using the same

Info

Publication number: CN109513455B
Application number: CN201811469861.9A
Authority: CN
Inventors: 余渡江; 黄东平; 邢益辉; 魏斌; 范春元
Original assignee: Hongbaoli Group Co ltd
Current assignee: HONGBAOLI GROUP Co.,Ltd.; RED POLAROID GROUP TAIXING CHEMICAL Co.,Ltd.
Priority date: 2018-12-04
Filing date: 2018-12-04
Publication date: 2021-09-24
Anticipated expiration: 2038-12-04
Also published as: CN109513455A

Abstract

The invention discloses an epoxidation catalyst which comprises 2-15 wt% of TiO₂(ii) a 84-96 wt% of SiO₂(ii) a 0.75 to 3 wt% of M; TiO 2₂And SiO₂The total amount of (A) is 97-99.25 wt%; the epoxidation catalyst has a pore diameter of 9-30 nm and a specific surface area of 210-700 m²(ii)/g; wherein M is CaO, Fe₂O₃CuO or Cr₂O₃At least one of (1). The preparation method of the epoxidation catalyst comprises the following steps: (11) adding a template agent, a pH regulator and water into a reactor to prepare mesoporous silica gel powder; (12) roasting the mesoporous silica gel powder, the extrusion aid and the adhesive to prepare a formed molecular sieve; (13) adding a formed molecular sieve into a reaction furnace for roasting, pumping a titanium source, and soaking by using a first soaking solution; (14) cleaning, drying, and adding a modifier to prepare the epoxidation catalyst. The application also provides a method for using the catalyst. The catalyst has the advantage of recycling under the condition of ensuring high efficiency, and the preparation method is clean.

Description

Epoxidation catalyst, method of making and method of using the same

Technical Field

The invention relates to an epoxidation catalyst, a preparation method and a use method thereof, and belongs to the field of catalyst synthesis and application.

Background

Propylene oxide is an important basic organic chemical raw material. The traditional process for producing the propylene oxide by the chlorohydrination method has heavy pollution and large corrosion. On the important premise of environmental protection, the development of an epoxidation green production technology with simple process flow, cleanness and economy is particularly important. The preparation of epoxy compounds by oxidation of olefins in related solvents with organic peroxides has been rapidly developed in the last two decades. Such as cumene hydroperoxide, has become one of the development of propylene oxide production technology due to low pollution and no coproduct formation. Ethylbenzene hydroperoxide propylene oxide from Shell is also used commercially on a large scale. Therefore, the olefin epoxidation catalyst is the core of technical breakthrough, and the structural morphology and the composition of the catalyst directly influence the conversion rate of raw materials and the selectivity of products. The service life of the catalyst directly affects the production cost.

Data research shows that the titanium silicalite molecular sieve has good catalytic activity for the selective oxidation of olefins and is a better catalyst in epoxidation reaction. The mesoporous (2-50 nm) molecular sieve can meet the requirements of molecular sizes of ethylbenzene hydroperoxide and cumene hydroperoxide. Organic peroxide source and olefin are diffused in the pore channel of the titanium-silicon molecular sieve, and contact metal elements are easy to react to prepare corresponding products. Researches show that organic matters can be deposited and blocked in the molecular sieve pore channels along with the reaction. Greatly reducing the service life of the catalyst. Therefore, there is a trend toward the development of highly efficient catalysts which can be recycled.

Disclosure of Invention

The invention aims to provide a catalyst which has the advantage of recycling under the condition of ensuring high efficiency, and the specific technical scheme is as follows:

an epoxidation catalyst comprising

2-15 wt% of TiO₂(ii) a 84-96 wt% of SiO₂(ii) a 0.75 to 3 wt% of M; TiO 2₂And SiO₂The total amount of (A) is 97-99.25 wt%; the epoxidation catalyst has a pore diameter of 9-30 nm and a specific surface area of 210-700 m²(ii)/g; wherein M is CaO, Fe₂O₃CuO or Cr₂O₃At least one of (1).

The catalyst has large aperture and high specific surface area, is extremely beneficial to the contact and leaving of reactants entering and exiting catalyst pore passages and metal, and improves the catalytic efficiency. The catalyst can be used as a catalyst for propylene epoxidation, and has good economic performance. Provides a high-efficiency metal composite catalyst for preparing propylene oxide by oxidizing propylene with organic peroxide.

The catalyst can assist the circulation of impregnation, cleaning and re-impregnation of metal elements, so that the high-efficiency stability of the titanium-silicon molecular sieve is ensured, and the processes of pore channel dredging and recycling are realized. The catalyst can be recycled on the basis of ensuring good catalytic effect.

The catalyst can make the conversion rate more than or equal to 99.9% and the selectivity more than or equal to 99.5%.

Secondly, the application also provides a preparation method of the epoxidation catalyst, which comprises the following steps:

(11) adding a template agent, a pH regulator and water into a reactor, heating to 40-90 ℃, stirring for 0.5-1.5 h, adding a silicon source, keeping the temperature at 40-90 ℃ for 12-48 h, raising the temperature of the reactor to 120-150 ℃, continuing to react for 12-48 h, then cooling to room temperature, filtering and drying to obtain mesoporous silica gel powder;

(12) uniformly mixing the mesoporous silica gel powder, the extrusion aid and the adhesive in proportion, and performing extrusion molding to form a molded product; drying the formed product at 100-180 ℃ for 12-24 h, and then roasting at 400-850 ℃ for 3-5 h to obtain a formed molecular sieve;

(13) adding a formed molecular sieve into a reaction furnace, keeping the temperature of the reaction furnace at 400-900 ℃, pumping a titanium source from the top of the reaction furnace, keeping the temperature for 6-12 hours, cooling to 60-90 ℃, adding a first impregnation liquid for impregnation, discharging and exhausting the first impregnation liquid after impregnating for 4-12 hours, wherein the first impregnation liquid is a first metal hydroxide solution;

(14) controlling the temperature of the reaction furnace at 100-400 ℃, adding deionized water for cleaning, keeping the temperature and drying for 8-24 h after cleaning, reducing the furnace temperature to 90-160 ℃, adding a modifier, and keeping the temperature for 2-10 h to obtain the epoxidation catalyst.

The preparation method controls the product index by adjusting the reaction temperature in the later stage, simplifies the removal process of template extraction or roasting, and reduces water and gas pollution.

Preferably, in the preparation method of the epoxidation catalyst,

in the step (11), the mass ratio of the template agent, the pH regulator, the water and the silicon source is 1: 0.1-0.3: 10-25: 3-10;

in the step (12), the mass ratio of the mesoporous silica gel powder to the extrusion aid to the adhesive is 1: 0.03-0.1: 0.3 to 1;

in the step (13), the mass ratio of the formed molecular sieve to the titanium source is 1: 0.1 to 0.5;

in the step (13), the first metal hydroxide solution is a metal hydroxide aqueous solution, a solution of metal hydroxide dissolved in a first acid, a solution of metal hydroxide dissolved in a first base, a solution of metal hydroxide dissolved in a first solvent, or a metal hydroxide colloidal solution, and the mass concentration of the first metal hydroxide solution is 0.1 to 2 wt%;

the first acid is hydrochloric acid, nitric acid or perchloric acid, the first alkali is ammonia water or ammonium salt solution, and the first solvent is glycerol or sodium cyanide solution;

in the step (14), the mass ratio of the deionized water to the formed molecular sieve to the modifier is 2-5: 1: 0.1 to 0.5.

In the scheme, the first metal hydroxide is introduced in the form of solution or colloidal solution, so that the dispersity of metal elements is improved, a large number of unreacted titanium sources can be removed in the dipping process, and the influence of non-framework titanium on the catalytic performance is reduced. The addition of the modifier improves the overall hydrophobic performance of the catalyst and reduces the influence of moisture on the use of the catalyst.

Further, in the step (11), the template agent is selected from at least one of dodecylamine, hexadecylamine, polyethylene glycol 4000, tween 80 or sodium dodecylbenzene sulfonate;

in the step (11), the pH regulator is at least one selected from oxalic acid, ammonia water, glacial acetic acid, citric acid or tetramethyl ammonium hydroxide;

in the step (11), the silicon source is at least one selected from a silicon dioxide aqueous solution, liquid silica sol or sodium silicate;

in the step (12), the extrusion aid is selected from at least one of hydroxypropyl methylcellulose, sesbania gum or polyethylene glycol 6000;

in the step (12), the adhesive is selected from a silicon dioxide aqueous solution or a silicon sol, and the mass concentration of silicon dioxide in the silicon dioxide aqueous solution or the silicon sol is 5-40%;

in the step (13), the titanium source is at least one selected from titanium tetrachloride, tetramethyl titanate, tetraethyl titanate, tetrapropyl titanate and tetrabutyl titanate;

in the step (13), the metal hydroxide in the first metal hydroxide solution is selected from at least one of calcium hydroxide, iron hydroxide, copper hydroxide or chromium hydroxide;

in the step (14), the modifier is at least one selected from hexamethyldisilazane, tetramethyldisilazane, trimethylchlorosilane, trimethylbromosilane or trimethyliodosilane.

In the scheme, the silicon source avoids the selection of organic silicate, the hydrophilic property of the silica gel powder is improved, more attachment points are provided for metal, and the matching property with the adhesive is improved.

Again, the present application also provides a method of using the above epoxidation catalyst comprising the steps of:

(21) loading an epoxidation catalyst into a tubular reactor, controlling the temperature of the reactor to be 60-125 ℃, adding a propylene and organic peroxide mixed solution, sampling and analyzing the gas phase composition of a reaction product, and titrating and analyzing the conversion rate of the organic peroxide;

(22) when the reaction temperature is 5-10 ℃ lower than the set reaction temperature, stopping adding the organic peroxide mixed solution, stopping adding propylene, adding a second impregnation solution for impregnation, discharging and exhausting the second impregnation solution after impregnating for 4-12 hours, circularly introducing a relevant solvent to clean the epoxidation catalyst, and repeatedly recycling the epoxidation catalyst after cleaning for 4-12 hours; the second impregnation solution is a second metal hydroxide solution.

In the scheme, the catalytic performance of the catalyst can be effectively monitored by combining temperature (reaction heat) and conversion rate detection, and the process stability is improved. And the catalyst pore channel structure can be effectively dredged by re-dipping and cleaning, the loss of active metal is avoided, and the service life of the catalyst is prolonged. The circulation of the impregnation, cleaning and re-impregnation of the auxiliary metal elements not only ensures the high-efficiency stability of the titanium silicalite molecular sieve, but also realizes the processes of dredging the pore channel and recycling;

preferably, in step (21), the molar ratio of propylene to organic peroxide is 1: 4-16; in the step (22), the mass ratio of the relevant solvent to the epoxidation catalyst is 1: 2 to 5.

In the above scheme, the solvent can effectively remove residual impurities in the impregnation liquid, and meanwhile, the solvent can also take away residual moisture, so that the reduction of the hydrophobic property of the catalyst after modification is effectively avoided.

In the step (22), the organic peroxide mixed solution is a mixed solution of cumene hydroperoxide and cumene; or the organic peroxide mixed solution is a mixed solution of ethylbenzene hydroperoxide and ethylbenzene; the mass percentage of the organic peroxide is 25-55%; when the organic peroxide mixed solution is a mixed solution of cumene hydroperoxide and cumene, the related solvent is the cumene; when the organic peroxide mixed solution is a mixed solution of ethylbenzene hydroperoxide and ethylbenzene, the relevant solvent is ethylbenzene.

In the scheme, the propylene oxide prepared by oxidizing the propylene by the organic peroxide mixed solution has low water content, few byproducts and high product quality. And the hydrogen peroxide cumene method has no coproduction, low pollution and material recycling.

Preferably, in the step (22), the second metal hydroxide solution is an aqueous metal hydroxide solution, a solution of metal hydroxide dissolved in a second acid, a solution of metal hydroxide dissolved in a second base, a solution of metal hydroxide dissolved in a second solvent, or a metal hydroxide colloid solution, and the mass concentration of the second metal hydroxide solution is 0.1-2 wt%;

the second acid is hydrochloric acid, nitric acid or perchloric acid, the second base is ammonia water or ammonium salt solution, and the second solvent is glycerol or sodium cyanide solution.

Detailed Description

Example 1

Adding 22g of polyethylene glycol 4000 and 500g of deionized water into a 1L reactor, heating to 60 ℃, stirring for 1h, adding 100g of an alkaline silica gel aqueous solution with the concentration of 40 wt%, keeping the temperature, stirring for 20h, heating to 125 ℃, continuing to react for 20h, filtering and roasting to obtain 35g of mesoporous silica gel powder; 2g of mixed gel formed by hydroxypropyl methyl cellulose and sesbania gum according to the mass ratio of 1:1, 75g of silicon dioxide aqueous solution with the concentration of 40 wt% and 15g of deionized water are added into mesoporous silica gel powder, are uniformly stirred and are extruded by a single-screw extruder to form a strip-shaped molecular sieve with the diameter of 2 mm. Drying at 125 deg.C for 20 hr, baking at 550 deg.C for 3.5 hr, and cutting into strips.

Adding 50g of strip molecular sieve into a reaction furnace, adding 12.5g of titanium tetrachloride at the furnace temperature of 610 ℃, and preserving the temperature for 8 h. And (3) cooling the furnace temperature to 70 ℃, adding 100g of 1 wt% calcium hydroxide solution, soaking for 8h, draining, heating the reaction furnace to 200 ℃, introducing 200g of deionized water, cleaning, and preserving heat and drying for 8h after water is added. The temperature of the reaction furnace is reduced to 150 ℃, 12.5g of metered hexamethyldisilazane is added, and the temperature is kept for 8 hours. The resulting catalyst was labeled # 1.

A certain amount of epoxidation catalyst prepared by the method is filled in a fixed bed reactor, the reaction pressure is controlled to be 2-5 MPa, the reaction temperature is controlled to be 40-160 ℃, the concentration of cumene hydroperoxide is 35 wt%, and the volume airspeed of the cumene hydroperoxide is 0.5-2 h^-1The molar ratio of propylene to cumene hydroperoxide was 10: 1. In the reaction process, if the conversion rate of the cumene hydroperoxide is lower than 95 percent, stopping adding the cumene hydroperoxide/cumene mixed solution and the propylene, adding 1 weight percent ferric hydroxide solution, soaking for 8 hours, discharging, and circularly introducing the cumene, cleaning for 8 hours and then continuously using. The use case is labeled P1.

Example 2

This example is substantially the same as example 1, except that: the amount of polyethylene glycol 4000 used was changed to 16.2g, and the procedure was repeated as in example 1. The resulting catalyst was labeled # 2. The use case is labeled P2.

Example 3

This example is substantially the same as example 1, except that: 22g of polyethylene glycol 4000 were replaced with 15g of hexadecylamine, and the rest was the same as in example 1. The resulting catalyst was labeled # 3. The use case is labeled P3.

Example 4

This example is substantially the same as example 1, except that: 100g of a 1% by weight calcium hydroxide solution was replaced with 100g of a 1% by weight ferric hydroxide colloidal solution, and the rest was the same as in example 1. The resulting catalyst was labeled # 4. The use case is labeled P4.

Example 5

This example is substantially the same as example 1, except that: 2g of a mixed gum formed by hydroxypropylmethylcellulose and sesbania gum in a mass ratio of 1:1 was replaced with 3g of sesbania gum, the amount of the aqueous silica solution having a concentration of 40 wt% was adjusted from 75g to 100g, and 100g of the calcium hydroxide solution having a concentration of 1 wt% was replaced with 80g of the glycerin copper hydroxide solution having a concentration of 1.2 wt%, and the rest was the same as in example 1. The resulting catalyst was labeled # 5. The use case is labeled P5.

Example 6

This example is substantially the same as example 1, except that: the molar ratio of propylene to cumene hydroperoxide was adjusted to 6: 1, the rest is the same as example 1. The resulting catalyst was labeled # 6. The use case is labeled P6.

The catalysts prepared in the examples were tested and the results are shown in Table 1. The effects of the catalysts prepared in the examples are shown in Table 2.

Table 1 test results of catalysts of each example

TABLE 2 Effect of catalyst use in examples

As can be seen from tables 1 and 2, the catalyst in the present application has a good structure and excellent catalytic and use properties.

Claims

1. An epoxidation catalyst comprising

2-15 wt% of TiO₂；

84-96 wt% of SiO₂；

0.75 to 3 wt% of M;

TiO₂and SiO₂The total amount of (A) is 97-99.25 wt%;

the epoxidation catalyst has a pore diameter of 9-30 nm and a specific surface area of 210-700 m²/g；

Wherein M is CaO, Fe₂O₃CuO or Cr₂O₃At least one of;

the epoxidation catalyst is prepared by the following steps:

(11) adding a template agent, a pH regulator and water into a reactor, heating to 40-90 ℃, stirring for 0.5-1.5 h, adding a silicon source, keeping the temperature at 40-90 ℃ for 12-48 h, raising the temperature of the reactor to 120-150 ℃, continuing to react for 12-48 h, then cooling to room temperature, filtering and drying to obtain mesoporous silica gel powder; the pH regulator is at least one selected from oxalic acid, ammonia water, glacial acetic acid, citric acid or tetramethyl ammonium hydroxide;

2. The epoxidation catalyst of claim 1,

3. The epoxidation catalyst of claim 1,

in the step (11), the template agent is selected from at least one of dodecylamine, hexadecylamine, polyethylene glycol 4000, tween 80 or sodium dodecyl benzene sulfonate;

4. The method of using the epoxidation catalyst of claim 1 comprising the steps of:

5. Use according to claim 4,

in the step (21), the molar ratio of propylene to the organic peroxide is 1: 4-16;

in the step (22), the mass ratio of the relevant solvent to the epoxidation catalyst is 1: 2 to 5.

6. Use according to claim 4,

in the step (22), the organic peroxide mixed solution is a mixed solution of cumene hydroperoxide and cumene; or

The organic peroxide mixed solution is a mixed solution of ethylbenzene hydroperoxide and ethylbenzene;

the mass percentage of the organic peroxide is 25-55%;

when the organic peroxide mixed solution is a mixed solution of cumene hydroperoxide and cumene, the related solvent is the cumene;

when the organic peroxide mixed solution is a mixed solution of ethylbenzene hydroperoxide and ethylbenzene, the relevant solvent is ethylbenzene.

7. Use according to claim 4,

in the step (22), the second metal hydroxide solution is a metal hydroxide aqueous solution, a solution of metal hydroxide dissolved in second acid, a solution of metal hydroxide dissolved in second base, a solution of metal hydroxide dissolved in second solvent, or a metal hydroxide colloid solution, and the mass concentration of the second metal hydroxide solution is 0.1-2 wt%;