WO2021103437A1 - Catalyst for preparing propylene epoxide and a preparation method therefor - Google Patents

Abstract

Disclosed is a catalyst for preparing propylene epoxide. The catalyst comprises 0.05-10 wt% of TiO 2, 0.5-2.9 wt% of M1, and 0.05-0.5 wt% of M2, with the balance being SiO 2; wherein M1 is at least one of Al 2O 3, SO 3 and Cr 2O 3; and M2 is at least one of P, W and Mo. The preparation method for the catalyst comprises: (1) mixing silicon powder, a plasticizer, an adhesive, a glue adjustment agent and M2, forming the mixture into a molded material, and drying and calcining the molded material to obtain a silicon strip; (2) adding the silicon strip into a reactor, adding a titanium source and allowing a reaction to occur, soaking the reaction mixture with a solution comprising M1, and discharging the solution after soaking is complete; and (3) soaking the reaction mixture with an acid solution, discharging the acid solution and rinsing the reaction mixture, then drying the reaction mixture to obtain the catalyst. The catalyst can significantly increase the purity of cumene and α,α-dimethylbenzyl alcohol as intermediate products in the preparation of propylene epoxide, which facilitates full use of materials. The method can successfully achieve the production of the catalyst.

Description

Catalyst for preparing propylene oxide and preparation method thereof Technical field

The invention relates to a catalyst for preparing propylene oxide by an oxidation method of cumene hydrogen peroxide and a preparation method thereof, and belongs to the field of catalyst synthesis.

Background technique

As a basic organic chemical raw material, propylene oxide is widely used in chemical fields such as polyethers and adhesives. Under severe environmental pressure, the traditional chlorohydrin method for the production of propylene oxide and equipment are gradually being replaced, eliminated or even shut down. Under this opportunity, clean and economical green preparation and production technology are gradually developed and industrialized. The process of preparing propylene oxide from propylene oxide after diluting organic peroxides with associated solvents is developing rapidly. The process of preparing propylene oxide from cumene hydroperoxide and propylene oxide was first developed by Japan's Sumitomo Chemical Company. This method uses titanium silicon molecular sieve as a catalyst and cumene hydrogen peroxide as an oxygen source to epoxidize propylene to propylene oxide. This method is an environment-friendly clean production process with no pollution and good technical and economic efficiency.

In the preparation of propylene oxide by the oxidation and oxidation of cumene hydrogen peroxide and related processes, the titanium silicon molecular sieve has good catalytic activity for the selective oxidation of olefins, the selectivity of propylene oxide is high, and the conversion rate of cumene hydrogen peroxide it is good. In the entire process, after the epoxidation reaction of the raw materials is completed, propylene is separated and propylene oxide is extracted to obtain a mixture of cumene and α,α-dimethylbenzyl alcohol (DMBA). The mixture is reduced by hydrogenolysis and then After oxidation, cumene hydrogen peroxide is generated, which effectively realizes the recycling of materials. Actual research shows that when the materials after the completion of the epoxidation reaction of the raw materials are separated from the titanium silica molecular sieve catalyst for subsequent processes, α,α-dimethylbenzyl alcohol will be decomposed into by-products, acetophenone and α-methylstyrene, which contain The mixture of by-products is extremely unfavorable for recycling. Therefore, in order to ensure the stability of the propylene oxide preparation process, without additional purification, develop a propylene oxide with high selectivity, good conversion of cumene hydrogen peroxide, cumene and α,α-dimethylbenzyl The catalyst with high purity of alcohol (DMBA) mixed liquid and gas phase is of great significance.

Summary of the invention

The purpose of this application is to achieve the above-mentioned goals and provide a catalyst for the production of propylene oxide by the oxidation of cumene hydroperoxide with propylene. The catalyst can greatly improve the intermediate products on the basis of ensuring high-efficiency selectivity and conversion rate. The purity of cumene and α,α-dimethylbenzyl alcohol facilitates the full use of materials. The specific technical solutions are:

A catalyst for preparing propylene oxide, which contains _{0.05-10wt% TiO 2} , 0.5-2.9wt% M1, 0.05-0.5wt% M2, and the remaining components are SiO ₂ ; M1 is Al ₂ O ₃ , At least one of SO ₃ or Cr ₂ O ₃ ; M2 is at least one of P, W or Mo; the pore diameter of the catalyst is 5-15 nm, the specific surface area is 150-560 m ² /g, and the total amount is calculated as 100 wt%.

The catalyst has moderate pore size and specific surface area, which facilitates the contact between the reactants and the active metal in the catalyst and the effective separation, improves the catalytic efficiency, and has good economic performance. A high-efficiency metal composite catalyst is provided for the preparation of propylene oxide from cumene hydrogen peroxide and propylene oxide.

The catalyst is added with the auxiliary metal element M2, which not only ensures the high-efficiency stability of the titanium silicon molecular sieve, but also effectively inhibits the oxidative dehydration of α,α-dimethylbenzyl alcohol. On the basis of ensuring that the catalyst has a good catalytic effect, no additional purification process is added, and the content of by-products in the mixed solution of cumene and α,α-dimethylbenzyl alcohol is greatly reduced to ensure the overall preparation process of propylene oxide Efficient and stable progress.

Using this catalyst, the conversion rate of cumene hydrogen peroxide is ≥99.9%, the selectivity of propylene oxide is ≥99.5%, and the gas phase purity of the mixed solution of cumene and α,α-dimethylbenzyl alcohol is ≥99.6%.

Secondly, this application also provides a preparation method of the above-mentioned catalyst, which includes the following steps:

(Ⅰ) Mix the silicon powder, plasticizer, adhesive, glue adjuster and M2 according to the set ratio, extrude or compression mould into a shaped object; dry the shaped object at 40～140℃ for 10～36h, Then it is calcined at 250～900℃ for 2.5～17h to obtain silicon strips;

(II) Add silicon strips to the reactor, control the temperature in the reactor at 200～900℃, bring the titanium source into the titanium source from the vaporizer at the bottom of the reaction, keep the temperature for 4～26h, then reduce to room temperature; then put the reactor inside Adjust the temperature to 30～190℃, pump the solution containing M1 from the top of the reactor, soak the silicon strips, and drain the solution containing M1 after soaking for 5～26h;

(Ⅲ) Adjust the temperature in the reactor to 25～90℃, pump the acid liquid from the top of the reactor, soak the silicon strips for 4～28h, then drain the acid liquid; adjust the temperature in the reactor to 80～400℃ , The catalyst is prepared by pumping in deionized water, cleaning it to neutrality, and keeping the temperature and drying for 10-28 hours.

In the preparation method, silicon powder is selected, the raw materials are readily available and cheap, and the relevant indicators are stable. The addition of the glue adjusting agent can effectively break the charge balance of the silica gel colloid and accelerate the gel curing. At the same time, the glue adjuster has certain water retention and lubricating properties, prevents rapid evaporation of water, and improves the overall crushing strength of the catalyst.

The vaporization of the titanium source can effectively improve the uniformity of the reaction, and the effective control of the reaction temperature can reduce the excessive accumulation of titanium caused by the reflux phenomenon. MI entering from the top can effectively improve the removal and departure of related substances.

Soaking in acid solution can effectively dechlorinate and free participating metal ions, improving the overall stability of the catalyst.

Preferably, in the preparation method of the catalyst,

In step (I), the mass ratio of silicon powder, plasticizer, adhesive, glue adjusting agent and M2 is 100: (0.5-10): (50-500): (0.5-5.0): (0.05-5.0).

In step (II), the mass ratio of the silicon strip to the titanium source is 100: (5-40); the mass ratio of the silicon strip to the M1 solution is 100: (400-8000).

In step (III), the mass ratio of silicon strip to acid solution is 100: (500-1000). The mass ratio of silicon strip to deionized water is 100: (500～50,000).

In the above scheme, M1 is a relatively stable ionic solution with good uniformity, and is also effectively exchanged and adsorbed on the silicon strip during the immersion process, and at the same time partially removes the unstable titanium dioxide. M2 effectively dissolves in the aqueous solution of the adhesive and effectively contacts with the silicon powder to improve the overall dispersibility.

Furthermore, in step (I), the pore diameter of the silicon powder is 5-15 nm; the specific surface area is 360-820 m ² /g.

In (I), the silica powder is at least one of column chromatography silica gel powder, macroporous silica gel powder, white carbon black or gas phase white carbon black;

In (I), the plasticizer is at least one of hydroxypropyl methylcellulose, sesame gum, polyethylene glycol 10000, and lignin;

In (I), the adhesive is silica sol or an aqueous silicon dioxide solution containing 1 to 3 wt% pseudo-boehmite, and the mass concentration of silicon dioxide in the adhesive is 5 to 60 wt%;

In (I), the glue adjusting agent is at least one of propylene glycol, polyethylene glycol 400, polyethylene glycol 200 or glycerol;

In (I), M2 is at least one of phosphotungstic acid, phosphomolybdic acid, silicotungstic acid or silimolybdic acid;

In (II), the titanium source is at least one of titanium tetrachloride, tetraethyl titanate, tetrapropyl titanate or tetrabutyl titanate;

In (II), the solution of M1 is at least one of sodium metaaluminate solution, aluminum trichloride solution, sodium sulfate solution, potassium sulfate solution or potassium dichromate solution;

In (III), the acid solution is at least one of hydrochloric acid solution, sulfuric acid solution, phosphoric acid solution or nitric acid solution, and the concentration of the acid solution is 0.25 to 1.6 moL/L. When the acid solution is a mixed solution of multiple acids, the concentration of the acid solution is the total concentration of the various acids.

In the above scheme, the addition of pseudo-boehmite not only supplements the metal source, but also improves the strength of the catalyst. An appropriate amount of M2 can be effectively dissolved in the adhesive aqueous solution, and an appropriate amount of acid can effectively exchange and remove unstable metal elements. .

Detailed ways

Example 1

Column chromatography silica gel powder (pore size 5nm, specific surface area 820m ² /g) 100g, hydroxypropyl methylcellulose 3g, 20wt% silica aqueous solution 500g, 0.5g polyethylene glycol 400 and 5g phosphotungstic acid After fully mixing, extrusion molding; the molded product was dried at 40°C for 36 hours, and then calcined at 900°C for 2.5 hours to obtain silicon strips.

The silica aqueous solution contains 1wt% pseudo-boehmite. Before use, the pseudo-boehmite is added to the silica aqueous solution and stirred uniformly.

Add 100 g of the calcined silicon rod to the reactor, the temperature of the reactor is controlled at 200 DEG C, 40 g of titanium tetrachloride is brought in with nitrogen from the vaporizer at the bottom of the reaction, kept for 26 hours, and then cooled to room temperature.

Then adjust the temperature in the reactor to 30°C, pump 400 g of 0.4 wt% potassium dichromate solution from the top of the reactor for soaking, and drain the solution after soaking for 26 hours.

The temperature of the reactor was controlled at 90°C, 500g of 1.6mol/L hydrochloric acid solution was pumped from the top, and the hydrochloric acid solution was drained after immersion for 4h. The temperature was increased to 400°C, and 50,000g of deionized water was pumped into it, washed to neutrality, and kept for 10h. The resulting catalyst is labeled Cat1#.

The catalyst prepared by the present invention is packed in a fixed bed reactor, the reaction pressure is 2MPa, the reaction temperature is 150°C, the concentration of cumene hydrogen peroxide is 55wt%, the volumetric space velocity of cumene hydrogen peroxide is 4h ^-1 , propylene and hydrogen peroxide The molar ratio of cumene is 15:1. After the reaction is completed, the propylene oxide is collected by a separator, and the mixture of cumene and α,α-dimethylbenzyl alcohol is sampled and gas-phase analyzed for percentage content and then used in the subsequent process. The usage is marked as CatP1*. This solution is only for evaluating the catalyst method, and this patent is not limited to this.

Example 2

Fully mix 100g fumed white carbon black (pore diameter 15nm, specific surface area 360m ² /g), 10g Sesbania Gum, 50g 60wt% silica aqueous solution, 1.5g propylene glycol and 0.1g phosphomolybdic acid, and then extrude and shape; The material was dried at 140°C for 10 hours, and then calcined at 250°C for 17 hours to obtain silicon strips.

The silicon dioxide aqueous solution contains 3wt% pseudo-boehmite. Before use, the pseudo-boehmite is added to the silicon dioxide aqueous solution and stirred uniformly.

Add 100 g of the calcined silicon rod to the reactor, the temperature of the reactor is controlled at 900°C, 5 g of tetrabutyl titanate is brought into the vaporizer at the bottom of the reaction with nitrogen, kept for 4 hours, and then cooled to room temperature.

Then adjust the temperature in the reactor to 30° C., pump 8000 g of 0.15 wt% sodium sulfate solution from the top of the reactor for soaking, and drain the solution after soaking for 5 hours.

The temperature of the reactor was controlled at 25°C, 10000g of 0.2mol/L sulfuric acid solution was pumped from the top, the sulfuric acid solution was drained after being soaked for 28h, the temperature was increased to 80°C, 500g of deionized water was pumped in, washed to neutrality, and then kept for 28 hours. The resulting catalyst is labeled Cat2#.

The catalyst prepared by the invention is packed in a fixed bed reactor, the reaction pressure is 8MPa, the reaction temperature is 40°C, the concentration of cumene hydrogen peroxide is 25wt%, the volumetric space velocity of cumene hydrogen peroxide is 0.1 ^-1 , propylene and hydrogen peroxide The molar ratio of cumene is 5:1. After the reaction is completed, the propylene oxide is collected by a separator, and the mixture of cumene and α,α-dimethylbenzyl alcohol is sampled and gas-phase analyzed for percentage content and then used in the subsequent process. The usage is marked as CatP2*.

Example 3

Column chromatography silica gel powder (pore size 10nm, specific surface area 590m ² /g) 100g, polyethylene glycol 10000 and hydroxypropyl methylcellulose each accounted for 6g of a mixture of 50wt, 300g silica sol containing 30wt% silica , 2.25g glycerol and 0.26g silicotungstic acid are fully mixed and extruded; the molded product is dried at 110°C for 23h, and then calcined at 650°C for 4.5h to obtain silicon strips.

Add 100 g of the calcined silicon rod to the reactor, the temperature of the reactor is controlled at 550°C, and 26 g of tetraethyl titanate is brought in with nitrogen from the vaporizer at the bottom of the reaction, kept for 10 hours, and then cooled to room temperature.

Then adjust the temperature in the reactor to 75° C., pump 600 g of 0.5 wt% aluminum trichloride solution from the top of the reactor for soaking, and drain the solution after soaking for 10 hours.

The temperature of the reactor was controlled at 50°C, and 4000g of 0.4mol/L phosphoric acid solution was pumped from the top, and the phosphoric acid solution was drained after soaking for 6 hours. The temperature was increased to 140°C, and 7000g of deionized water was pumped into the reactor to wash until it was neutral and kept for 14 hours. The resulting catalyst is labeled Cat3#.

The catalyst prepared by the present invention is packed in a fixed bed reactor, the reaction pressure is 4MPa, the reaction temperature is 100°C, the concentration of cumene hydrogen peroxide is 35wt%, the volumetric space velocity of cumene hydrogen peroxide is 2h ^-1 , propylene and hydrogen peroxide The molar ratio of cumene is 10:1. After the reaction is completed, the propylene oxide is collected by a separator, and the mixture of cumene and α,α-dimethylbenzyl alcohol is sampled and gas-phase analyzed for percentage content and then used in the subsequent process. The usage is marked as CatP3*.

Example 4

This embodiment is the same as embodiment 3, except that silicotungstic acid is replaced with silimolybdic acid, and other conditions remain unchanged. The resulting catalyst is labeled Cat4#. The evaluation method is the same as in Example 3, and the usage is marked as CatP4*.

Example 5

100g of macroporous silica gel powder (pore size 12nm, specific surface area 470m ² /g), 6g of a mixture of polyethylene glycol 10000 and hydroxypropyl methylcellulose each accounting for 50wt%, 300g and 2.25g of 30wt% silica aqueous solution Glycerol and 0.26 g of silicotungstic acid are fully mixed and then extruded; the molded product is dried at 60°C for 18 hours, and then calcined at 400°C for 10.5 hours to obtain silicon strips.

The silica aqueous solution contains 2wt% pseudo-boehmite. Before use, the pseudo-boehmite is added to the silica aqueous solution and stirred uniformly.

Add 100g of the calcined silicon rod to the reactor, the temperature of the reactor is controlled at 350°C, and 13g of titanium tetrachloride is brought in with nitrogen from the vaporizer at the bottom of the reaction, kept for 12h, and then cooled to room temperature.

Then adjust the temperature in the reactor to 100° C., pump 600 g of 0.5 wt% aluminum trichloride solution from the top of the reactor for soaking, and drain the solution after soaking for 15 hours.

The temperature of the reactor is controlled at 70°C, 2500g of 0.4mol/L phosphoric acid solution is pumped from the top, the phosphoric acid solution is drained after soaking for 12h, the temperature is increased to 200°C, and 5000g of deionized water is pumped into the reactor to wash until it is neutral, and then it is kept and dried for 20h. The resulting catalyst is labeled Cat5#. The evaluation method is the same as in Example 3, and the usage is marked as CatP5*.

Example 6

This embodiment is the same as Embodiment 5, except that phosphoric acid is replaced with sulfuric acid, the amount of titanium tetrachloride is 30 g, and the amount of silicotungstic acid is 0.1 g, and other conditions remain unchanged. The resulting catalyst is labeled Cat6#. The evaluation method is the same as in Example 3, and the usage is marked as CatP6*.

Example 7

This Example 7 is a comparative example.

This embodiment is the same as embodiment 3, except that pseudo-boehmite and silicotungstic acid are no longer added, and the 0.5wt% aluminum trichloride solution and 0.4mol/L phosphoric acid solution are replaced with the same amount of deionization water. The resulting catalyst is labeled Cat7#. The evaluation method is the same as in Example 3, and the usage is marked as CatP7*.

The test results of the catalysts in each embodiment are shown in Table 1, and the use effects are shown in Table 2.

Table 1 Catalyst detection results of each embodiment

Table 2 Effect of the catalyst in each example

mark	Conversion rate/%	Selectivity/%	Gas phase purity of mixed solution/%
CatP1*	99.96	99.81	99.81
CatP2*	99.98	99.63	99.63
CatP3*	100	99.58	99.91
CatP4*	99.97	99.55	99.86
CatP5*	99.95	99.61	99.78
CatP6*	99.99	99.72	99.90
CatP7*	99.96	99.62	98.21

The gas phase purity of the mixed solution in Table 2 means that the total volume of cumene and α,α-dimethylbenzyl alcohol is in the gas phase when the solution obtained after separating propylene oxide and propylene in the reaction product is tested under gas phase conditions. In the proportion. The higher the value, the higher the total content of cumene and α,α-dimethylbenzyl alcohol, and the smaller the total amount of by-products derived from decomposition.

Comprehensively available: Although the comparative example effectively ensures the high efficiency of the epoxidation catalyst, the gas phase purity of the mixed liquid of cumene and α,α-dimethylbenzyl alcohol decreases, indicating that part of α,α-dimethylbenzyl alcohol is produced In order to decompose, the total content of by-products increased significantly. The catalyst prepared by this scheme not only guarantees high efficiency in the use process, and at the same time, the gas phase purity of the mixed solution of cumene and α,α-dimethylbenzyl alcohol is high, and the total content of by-products is small, which effectively solves practical problems.

Claims (9)

1. A catalyst for preparing propylene oxide, which is characterized in that it contains _{0.05-10wt% of TiO 2} , 0.5-2.9wt% of M1, 0.05-0.5wt% of M2, and the remaining components are SiO ₂ , and the total amount is 100wt% %meter;

   M1 is at least one _{of Al 2} O ₃ , SO ₃ or Cr ₂ O _3;

   M2 is at least one of P, W or Mo;

   The pore diameter of the catalyst is 5-15nm, and the specific surface area is 150-560m ² /g.
2. A method for preparing a catalyst, which is used to prepare the catalyst according to claim 1, characterized in that it comprises the following steps:

   (Ⅰ) Mix the silicon powder, plasticizer, adhesive, glue adjuster and M2 according to the set ratio, extrude or compression mould into a shaped object; dry the shaped object at 40～140℃ for 10～36h, Then it is calcined at 250～900℃ for 2.5～17h to obtain silicon strips;

   (II) Add silicon strips to the reactor, control the temperature in the reactor at 200-900℃, bring nitrogen into the titanium source from the vaporizer at the bottom of the reaction, keep the temperature for 4 to 26 hours and then reduce to room temperature;

   Then adjust the temperature in the reactor to 30～190℃, pump the solution containing M1 from the top of the reactor, soak the silicon strips, and drain the solution containing M1 after soaking for 5～26h;

   (Ⅲ) Adjust the temperature in the reactor to 25～90℃, pump acid liquid from the top of the reactor, and drain the acid liquid after soaking the silicon strips for 4-28 hours;

   The temperature in the reactor is adjusted to 80-400°C, deionized water is pumped into the reactor, washed until it is neutral, and then kept and dried for 10-28 hours to prepare the catalyst.
3. The preparation method according to claim 2, wherein:

   In step (I), the mass ratio of silicon powder, plasticizer, adhesive, glue adjusting agent and M2 is 100: (0.5-10): (50-500): (0.5-5.0): (0.05-5.0).
4. The preparation method according to claim 2, wherein:

   In step (II), the mass ratio of the silicon strip to the titanium source is 100: (5-40).
5. The preparation method according to claim 2, wherein:

   In step (III), the mass ratio of the silicon strip to the M1 solution is 100: (400-8000).
6. The preparation method according to claim 2, wherein:

   In step (III), the mass ratio of silicon strip to acid solution is 100: (500-1000).
7. The preparation method according to claim 2, wherein:

   The mass ratio of silicon strip to deionized water is 100: (500～50,000).
8. The preparation method according to claim 2, wherein:

   In step (I), the silicon powder has a pore diameter of 5-15 nm and a specific surface area of 360-820 m ² /g.
9. The preparation method according to claim 2, wherein:

   In step (I), the silicon powder is at least one of column chromatography silica gel powder, macroporous silica gel powder, white carbon black or gas phase white carbon black;

   The plasticizer is at least one of hydroxypropyl methylcellulose, sesame gum, polyethylene glycol 10000, and lignin;

   The adhesive is silica sol or an aqueous silicon dioxide solution containing 1 to 3 wt% pseudo-boehmite, and the mass concentration of silicon dioxide in the adhesive is 5 to 60 wt%;

   The gumming agent is at least one of propylene glycol, polyethylene glycol 400, polyethylene glycol 200 or glycerol;

   In step (I), M2 is selected from at least one of phosphotungstic acid, phosphomolybdic acid, silicotungstic acid or silimolybdic acid;

   The titanium source is at least one of titanium tetrachloride, tetraethyl titanate, tetrapropyl titanate or tetrabutyl titanate;

   The solution of M1 is at least one of sodium metaaluminate solution, aluminum trichloride solution, sodium sulfate solution, potassium sulfate solution or potassium dichromate solution;

   The acid solution is at least one of a hydrochloric acid solution, a sulfuric acid solution, a phosphoric acid solution or a nitric acid solution, and the concentration of the acid solution is 0.25 to 1.6 moL/L.