Preparation method of epichlorohydrin and catalyst of epichlorohydrin

Abstract

The invention provides a preparation method of epichlorohydrin and a catalyst of the epichlorohydrin, and belongs to the technical field of organic chemistry. Hydrogen peroxide and chloropropene are used as raw materials to react under the action of a catalyst to generate epoxy chloropropane, and the catalyst takes layered metal oxide / Al2O3 / SiO2 microspheres as a carrier and is loaded with K and Mo, and the surface of the catalyst is modified by phytic acid and beta-cyclodextrin. The preparation method is simple, the conditions are mild, the reaction can be carried out under the normal pressure condition, the catalyst activity is high, multiple catalysis can be carried out, the reactant conversion rate is high, byproducts are few, and the conversion rate reaches 90% or above.

Description

Technical Field

[0001] The invention relates to the technical field of organic chemistry, and in particular to a method for preparing epichlorohydrin and a catalyst thereof. Background Art

[0002] Epichlorohydrin, also known as epichlorohydrin, has a chemical name of 3-chloro-1,2-epoxypropane. It is an important organic chemical raw material and synthetic intermediate. Among epoxy compounds, the output of epichlorohydrin ranks third after ethylene oxide and propylene oxide. Epichlorohydrin can be used as a solvent for cellulose esters, resins and cellulose ethers. It is also a raw material for the production of surfactants, medicines, pesticides, coatings, adhesives, ion exchange resins, plasticizers, glycerol derivatives and glycidol derivatives. Various epoxy resins prepared from epichlorohydrin and bisphenol A have the characteristics of strong adhesion, low shrinkage, chemical corrosion resistance and good stability. They are widely used as coatings, adhesives, reinforcement materials and casting materials. Epichlorohydrin rubber produced with epichlorohydrin as raw material is a new type of rubber. It is not easy to swell in ordinary solvents and has the unique function of greater flexibility (better than nitrile, chloroprene rubber and butyl rubber) at low temperature without plasticizers.

[0003] As an important organic chemical raw material and fine chemical product, epichlorohydrin is widely used in chemical, light industry, medicine, electronic and electrical industries. At present, there are three main methods for producing epichlorohydrin: propylene high-temperature chlorination method using propylene as raw material, propylene acetate method and glycerol method using glycerol as raw material. The propylene high-temperature chlorination method was first successfully developed and applied to industrial production by Shell Company of the United States in 1948. It is a classic method for producing epichlorohydrin. At present, more than 90% of epichlorohydrin in the world is produced by this method. However, the disadvantages of this process are that the raw material chlorine seriously corrodes the equipment, has high requirements on the purity of propylene and the material of the reactor, high energy consumption, high chlorine consumption, many by-products, low product yield (about 70%), and a large amount of wastewater containing calcium chloride and organic chlorides generated during production, high treatment costs, easy coking, and short coke cleaning cycle. In view of this shortcoming, people have developed a new method for preparing epichlorohydrin.

[0004] Chinese invention patent CN102453006B discloses a method for preparing epichlorohydrin by direct epoxidation of allyl chloride, in which allyl chloride in excess relative to the oxidant reacts with hydrogen peroxide as the oxidant under reflux in the presence of a quaternary ammonium phosphate additive under the action of a quaternary ammonium phosphotungstic heteropolyacid catalyst to directly generate epichlorohydrin. The catalyst is dissolved in the reaction solution during the reaction and precipitates after the reaction is completed, but there is a problem that the catalyst cannot be completely dissolved and cannot be completely precipitated, which directly affects the activity and recovery rate of the catalyst.

[0005] Chinese invention patent CN101747297B discloses a method for continuous production of epichlorohydrin, which includes introducing 3-chloropropene, hydrogen peroxide and solvent into multiple fixed bed reactors equipped with titanium silicon molecular sieve catalysts, so that 3-chloropropene and hydrogen peroxide undergo epoxidation reaction; stopping the epoxidation reaction in at least one fixed bed reactor and regenerating the catalyst therein, wherein, when any reactor is regenerating the catalyst, an epoxidation reaction is carried out in at least one of the other reactors. However, this method uses hydrogen peroxide as an oxidant, and since hydrogen peroxide decomposes at high temperatures, on the one hand, the utilization rate of the raw materials will decrease, and on the other hand, the decomposition of hydrogen peroxide will produce oxygen, and the mixture of oxygen and chloropropene is explosive. Summary of the invention

[0006] The object of the present invention is to provide a method for preparing epichlorohydrin and a catalyst thereof. The preparation method is simple, the conditions are mild, the reaction can occur under normal pressure, the catalyst has high activity, can catalyze multiple times, the conversion rate of reactants is high, the by-products are small, and the conversion rate reaches more than 90%.

[0007] The technical solution of the present invention is achieved in this way:

[0008] The invention provides a method for preparing epichlorohydrin. Hydrogen peroxide and allyl chloride are used as raw materials. Epichlorohydrin is generated by reaction under the action of a catalyst. The catalyst is a catalyst with layered metal oxide / Al2O3 / SiO2 microspheres as a carrier, loaded with K and Mo, and the surface of which is modified by phytic acid and beta-cyclodextrin.

[0009] As a further improvement of the present invention, the mass ratio of hydrogen peroxide to allyl chloride is 0.02-0.2:1.

[0010] As a further improvement of the present invention, the reaction temperature is 70-80° C., and the reaction time is 1-5 h.

[0011] As a further improvement of the present invention, the preparation method of the catalyst is as follows:

[0012] S1. Preparation of porous Al2O3 / SiO2 microspheres: Alkyl orthosilicate and aluminum isopropoxide were dissolved in ethanol, porogen, ammonia and water were added, stirred for reaction, centrifuged, washed, dried and calcined to obtain porous Al2O3 / SiO2 microspheres;

[0013] S2. Deposition of layered metal oxides: Dissolve zinc nitrate, iron nitrate and nickel nitrate in water, add alkali solution, add porous Al2O3 / SiO2 microspheres, heat for crystallization, filter, wash, dry and calcine to obtain layered metal oxide / Al2O3 / SiO2 microspheres;

[0014] S3. Impregnation: potassium carbonate and ammonium molybdate were dissolved in water to prepare an impregnation solution, layered metal oxide / Al2O3 / SiO2 microspheres were added, and the solvent was evaporated to obtain a mixture;

[0015] S4 Calcination: The mixture was calcined to obtain K / Mo- layered metal oxide / Al2O3 / SiO2 microspheres;

[0016] S5. Preparation of catalyst: Add K / Mo-layered metal oxide / Al2O3 / SiO2 microspheres, phytic acid, β-cyclodextrin and potassium dihydrogen phosphate into water, perform hydrothermal reaction, filter, wash and dry to obtain a catalyst.

[0017] As a further improvement of the present invention, the alkyl orthosilicate in step S1 is methyl orthosilicate or ethyl orthosilicate, the mass ratio of the alkyl orthosilicate, aluminum isopropoxide, porogen, ammonia water and water is 12-15:7-10:2-3:5-7:10-12, the stirring reaction time is 7-10h, the calcination temperature is 400-500°C, the time is 2-4h, and the porogen is hexadecyltrimethylammonium bromide.

[0018] As a further improvement of the present invention, the mass ratio of zinc nitrate, iron nitrate, nickel nitrate, and Al2O3 / SiO2 microspheres in step S2 is 3-4:5-7:1-2:10, the pH value of the solution is adjusted to 7-7.5 by dropping alkali solution, the heating crystallization temperature is 85-95°C, the time is 20-40min, the calcination temperature is 600-700°C, the time is 2-4h, and the alkali solution is 0.5-1mol / L NaOH or KOH solution.

[0019] As a further improvement of the present invention, the mass ratio of potassium carbonate, ammonium molybdate and layered metal oxide / Al2O3 / SiO2 microspheres in step S3 is 3-5:7-10:13-17.

[0020] As a further improvement of the present invention, the calcination temperature in step S4 is 600-800° C. and the calcination time is 1-3 h.

[0021] As a further improvement of the present invention, the mass ratio of K / Mo-layered metal oxide / Al2O3 / SiO2 microspheres, phytic acid, β-cyclodextrin, and potassium dihydrogen phosphate in step S5 is 10:3-5:5-7:0.2-0.5, and the temperature of the hydrothermal reaction is 130-160°C and the time is 8-10h.

[0022] The present invention further protects a catalyst as described above, the preparation method of which comprises the following steps:

[0023] S1. Preparation of porous Al2O3 / SiO2 microspheres: 12-15 parts by weight of alkyl orthosilicate and 7-10 parts by weight of aluminum isopropoxide were dissolved in ethanol, 2-3 parts by weight of a porogen, 5-7 parts by weight of aqueous ammonia and 10-12 parts by weight of water were added, the reaction was stirred for 7-10 hours, centrifuged, washed, dried, and calcined at 400-500°C for 2-4 hours to obtain porous Al2O3 / SiO2 microspheres;

[0024] S2. Deposition of layered metal oxides: 3-4 parts by weight of zinc nitrate, 5-7 parts by weight of iron nitrate, and 1-2 parts by weight of nickel nitrate were dissolved in water, 0.5-1 mol / L of NaOH or KOH solution was added dropwise to adjust the pH value of the solution to 7-7.5, 10 parts by weight of Al2O3 / SiO2 microspheres were added, heated to 85-95°C, crystallized for 20-40min, filtered, washed, dried, and calcined at 600-700°C for 2-4h to obtain layered metal oxides / Al2O3 / SiO2 microspheres;

[0025] S3 impregnation: 3-5 parts by weight of potassium carbonate and 7-10 parts by weight of ammonium molybdate were dissolved in water to obtain an impregnation solution, 13-17 parts by weight of layered metal oxide / Al2O3 / SiO2 microspheres were added, and the solvent was evaporated to obtain a mixture;

[0026] S4 Calcination: The mixture was calcined at 600-800 ℃ for 1-3h to obtain K / Mo- layered metal oxide / Al2O3 / SiO2 microspheres;

[0027] S5. Preparation of catalyst: add 10 parts by weight of K / Mo-layered metal oxide / Al2O3 / SiO2 microspheres, 3-5 parts by weight of phytic acid, 5-7 parts by weight of β-cyclodextrin, and 0.2-0.5 parts by weight of potassium dihydrogen phosphate into water, carry out hydrothermal reaction at 130-160°C for 8-10 hours, filter, wash, and dry to obtain the catalyst.

[0028] The present invention has the following beneficial effects:

[0029] Molybdenum is a transition metal element of Group VI, and its N and O electron layers are not completely distributed, which makes it easier for the molybdenum element to give and accept electrons. Therefore, molybdenum has a variety of variable valences, so that molybdenum has good catalytic properties. In the present invention, Mo metal has good catalytic activity, and the addition of K has a synergistic catalytic effect.

[0030] The present invention uses porous Al2O3 / SiO2 microspheres as one of the carriers. When γ-Al2O3 is used alone as a carrier, it is easy to react with the precursor and affect the catalytic activity. Therefore, the Al2O3 / SiO2 microspheres prepared by using composite oxides as carriers can not only maintain the structural advantage of the large specific surface area of ​​γ-Al2O3, but also inhibit the contact between the precursor and γ-Al2O3, so as to better exert the catalytic activity. Further, the surface is deposited with ZnNiFe layered metal oxides, which, on the one hand, increases the specific surface area of ​​the catalyst and helps to increase the loading amount of K and Mo, and on the other hand, the metal Zn, Ni and Fe have a good effect of promoting the catalytic effect and improve the conversion rate of the reaction.

[0031] The present invention further loads phytic acid and β-cyclodextrin on the surface, and the synthesis route is as follows:

[0032]

[0033] The cavities of phytic acid and beta-cyclodextrin help hydrogen peroxide and propylene chloride to contact the catalyst, promote their in-situ reaction, improve catalytic activity, and improve reaction conversion rate, so that the present invention has good conversion efficiency at lower temperature and room temperature, and the conversion rate reaches more than 90%.

[0034] The preparation method of the invention is simple and has mild conditions. The reaction can occur under normal pressure. The catalyst has high activity and can catalyze multiple times. The conversion rate of reactants is high and the by-products are small. The conversion rate reaches more than 90%. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] Example 1

[0037] This embodiment provides a catalyst, and the preparation method includes the following steps:

[0038] S1. Preparation of porous Al2O3 / SiO2 microspheres: 12 g of methyl orthosilicate and 7 g of aluminum isopropoxide were dissolved in 100 mL of ethanol, 2 g of hexadecyltrimethylammonium bromide, 5 g of ammonia water and 10 g of water were added, the mixture was stirred for 7 h, centrifuged, washed, dried, and calcined at 400 ° C for 2 h to obtain porous Al2O3 / SiO2 microspheres;

[0039] S2. Deposition of layered metal oxides: 3 g zinc nitrate, 5 g iron nitrate, and 1 g nickel nitrate were dissolved in 200 mL water, 0.5 mol / L NaOH solution was added dropwise to adjust the solution pH to 7, 10 g porous Al2O3 / SiO2 microspheres were added, heated to 85°C, crystallized for 20 min, filtered, washed, dried, and calcined at 600°C for 2 h to obtain layered metal oxide / Al2O3 / SiO2 microspheres;

[0040] S3 impregnation: 3g potassium carbonate and 7g ammonium molybdate were dissolved in 150mL of water to prepare an impregnation solution, 13g of layered metal oxide / Al2O3 / SiO2 microspheres were added, and the solvent was evaporated to obtain a mixture;

[0041] S4. Calcination: The mixture was calcined at 600 ° C for 1 h to obtain K / Mo- layered metal oxide / Al2O3 / SiO2 microspheres;

[0042] S5. Preparation of catalyst: Add 10g K / Mo-layered metal oxide / Al2O3 / SiO2 microspheres, 3g phytic acid, 5g β-cyclodextrin, and 0.2g potassium dihydrogen phosphate into 200mL water, carry out hydrothermal reaction at 130°C for 8h, filter, wash, and dry to obtain the catalyst.

[0043] Example 2

[0044] This embodiment provides a catalyst, and the preparation method includes the following steps:

[0045] S1. Preparation of porous Al2O3 / SiO2 microspheres: 15 g of tetraethyl orthosilicate and 10 g of aluminum isopropoxide were dissolved in 100 mL of ethanol, 3 g of hexadecyltrimethylammonium bromide, 7 g of ammonia water and 12 g of water were added, stirred for 10 h, centrifuged, washed, dried, and calcined at 500 ° C for 4 h to obtain porous Al2O3 / SiO2 microspheres;

[0046] S2. Deposition of layered metal oxides: 4 g zinc nitrate, 7 g iron nitrate, and 2 g nickel nitrate were dissolved in 200 mL water, 1 mol / L KOH solution was added dropwise to adjust the solution pH to 7.5, 10 g porous Al2O3 / SiO2 microspheres were added, heated to 95°C, crystallized for 40 min, filtered, washed, dried, and calcined at 700°C for 4 h to obtain layered metal oxide / Al2O3 / SiO2 microspheres;

[0047] S3 impregnation: 5g potassium carbonate and 10g ammonium molybdate were dissolved in 150mL of water to prepare an impregnation solution, 17g of layered metal oxide / Al2O3 / SiO2 microspheres was added, and the solvent was evaporated to obtain a mixture;

[0048] S4 Calcination: The mixture was calcined at 800 ° C for 3h to obtain K / Mo- layered metal oxide / Al2O3 / SiO2 microspheres;

[0049] S5. Preparation of catalyst: Add 10g K / Mo-layered metal oxide / Al2O3 / SiO2 microspheres, 5g phytic acid, 7g β-cyclodextrin, and 0.5g potassium dihydrogen phosphate into 200mL water, carry out hydrothermal reaction at 160°C for 10h, filter, wash, and dry to obtain the catalyst.

[0050] Example 3

[0051] This embodiment provides a catalyst, and the preparation method includes the following steps:

[0052] S1. Preparation of porous Al2O3 / SiO2 microspheres: 13 g of tetraethyl orthosilicate and 8 g of aluminum isopropoxide were dissolved in 100 mL of ethanol, 2.5 g of hexadecyltrimethylammonium bromide, 6 g of ammonia water and 11 g of water were added, the mixture was stirred for 8 h, centrifuged, washed, dried, and calcined at 450 ° C for 3 h to obtain porous Al2O3 / SiO2 microspheres;

[0053] S2. Deposition of layered metal oxides: 3.5 g zinc nitrate, 6 g iron nitrate, and 1.5 g nickel nitrate were dissolved in 200 mL water, 0.7 mol / L KOH solution was added dropwise to adjust the solution pH to 7.5, 10 g porous Al2O3 / SiO2 microspheres were added, heated to 90°C, crystallized for 30 min, filtered, washed, dried, and calcined at 650°C for 3 h to obtain layered metal oxide / Al2O3 / SiO2 microspheres;

[0054] S3 impregnation: 4g potassium carbonate and 8g ammonium molybdate were dissolved in 150mL of water to prepare an impregnation solution, 15g of layered metal oxide / Al2O3 / SiO2 microspheres was added, and the solvent was evaporated to obtain a mixture;

[0055] S4. Calcination: The mixture was calcined at 650 ° C for 2 h to obtain K / Mo- layered metal oxide / Al2O3 / SiO2 microspheres;

[0056] S5. Preparation of catalyst: Add 10g K / Mo-layered metal oxide / Al2O3 / SiO2 microspheres, 4g phytic acid, 6g β-cyclodextrin, and 0.3g potassium dihydrogen phosphate into 200mL water, carry out hydrothermal reaction at 145°C for 9h, filter, wash, and dry to obtain the catalyst.

[0057] Comparative Example 1

[0058] Compared with Example 3, the difference is that tetraethyl orthosilicate is not added in step S1.

[0059] The details are as follows:

[0060] S1. Preparation of porous Al2O3 microspheres: Dissolve 21 g of aluminum isopropoxide in 100 mL of ethanol, add 2.5 g of hexadecyltrimethylammonium bromide, 6 g of ammonia water and 11 g of water, stir and react for 8 h, centrifuge, wash, dry, and calcine at 450°C for 3 h to obtain porous Al2O3 microspheres.

[0061] Comparative Example 2

[0062] Compared with Example 3, the difference is that cetyltrimethylammonium bromide is not added in step S1.

[0063] The details are as follows:

[0064] S1. Preparation of Al2O3 / SiO2 microspheres: Dissolve 13g of tetraethyl orthosilicate and 8g of aluminum isopropoxide in 100mL of ethanol, add 6g of ammonia water and 11g of water, stir and react for 8h, centrifuge, wash, dry, and calcine at 450℃ for 3h to obtain Al2O3 / SiO2 microspheres.

[0065] Comparative Example 3

[0066] Compared with Example 3, the difference is that step S2 is not performed.

[0067] The details are as follows:

[0068] S1. Preparation of porous Al2O3 / SiO2 microspheres: 13 g of tetraethyl orthosilicate and 8 g of aluminum isopropoxide were dissolved in 100 mL of ethanol, 2.5 g of hexadecyltrimethylammonium bromide, 6 g of ammonia water and 11 g of water were added, the mixture was stirred for 8 h, centrifuged, washed, dried, and calcined at 450 ° C for 3 h to obtain porous Al2O3 / SiO2 microspheres;

[0069] S2 impregnation: 4g potassium carbonate and 8g ammonium molybdate were dissolved in 150mL of water to prepare an impregnation solution, 15g of porous Al2O3 / SiO2 microspheres was added, and the solvent was evaporated to obtain a mixture;

[0070] S3 Calcination: The mixture was calcined at 650 ° C for 2h to obtain K / Mo-Al2O3 / SiO2 microspheres;

[0071] S4. Preparation of catalyst: Add 10g K / Mo-Al2O3 / SiO2 microspheres, 4g phytic acid, 6g β-cyclodextrin, and 0.3g potassium dihydrogen phosphate into 200mL water, carry out hydrothermal reaction at 145°C for 9h, filter, wash, and dry to obtain the catalyst.

[0072] Comparative Example 4

[0073] Compared with Example 3, the difference is that potassium carbonate is not added in step S3.

[0074] The details are as follows:

[0075] S3. Impregnation: 12 g of ammonium molybdate was dissolved in 150 mL of water to prepare an impregnation solution, 15 g of layered metal oxide / Al2O3 / SiO2 microspheres were added, and the solvent was evaporated to obtain a mixture.

[0076] Comparative Example 5

[0077] Compared with Embodiment 3, the difference is that step S5 is not performed.

[0078] The details are as follows:

[0079] S1. Preparation of porous Al2O3 / SiO2 microspheres: 13 g of tetraethyl orthosilicate and 8 g of aluminum isopropoxide were dissolved in 100 mL of ethanol, 2.5 g of hexadecyltrimethylammonium bromide, 6 g of ammonia water and 11 g of water were added, the mixture was stirred for 8 h, centrifuged, washed, dried, and calcined at 450 ° C for 3 h to obtain porous Al2O3 / SiO2 microspheres;

[0080] S2. Deposition of layered metal oxides: 3.5 g zinc nitrate, 6 g iron nitrate, and 1.5 g nickel nitrate were dissolved in 200 mL water, 0.7 mol / L KOH solution was added dropwise to adjust the solution pH to 7.5, 10 g porous Al2O3 / SiO2 microspheres were added, heated to 90°C, crystallized for 30 min, filtered, washed, dried, and calcined at 650°C for 3 h to obtain layered metal oxide / Al2O3 / SiO2 microspheres;

[0081] S3 impregnation: 4g potassium carbonate and 8g ammonium molybdate were dissolved in 150mL of water to prepare an impregnation solution, 15g of layered metal oxide / Al2O3 / SiO2 microspheres was added, and the solvent was evaporated to obtain a mixture;

[0082] S4. Calcination: Calcinate the mixture at 650°C for 2h to obtain K / Mo-layered metal oxide / Al2O3 / SiO2 microspheres, which are the catalyst.

[0083] Test Example 1

[0084] The specific surface area and total pore volume of the catalysts for preparing diethyltoluenediamine prepared in Examples 1-3 and Comparative Examples 1-5 were measured using a multi-station high-throughput gas adsorption instrument.

[0085] The results are shown in Table 1.

[0086] Table 1

[0087] Group <![CDATA[Specific surface area (m 2 / g)]]> <![CDATA[Total pore volume (cm 3 / g)]]> Example 1 844.1 0.711 Example 2 845.9 0.712 Example 3 847.8 0.715 Comparative Example 1 821.5 0.689 Comparative Example 2 774.5 0.612 Comparative Example 3 721.9 0.578 Comparative Example 4 831.2 0.704 Comparative Example 5 815.7 0.694

[0088] It can be seen from the above table that the catalysts prepared in Examples 1-3 of the present invention have larger specific surface areas and total pore volumes.

[0089] Example 4

[0090] The present embodiment provides a method for preparing epichlorohydrin, using hydrogen peroxide and allyl chloride as raw materials, wherein the mass ratio of hydrogen peroxide to allyl chloride is 0.1:1, under the action of the catalyst prepared in Example 1, the added amount of the catalyst is 5wt% of the allyl chloride, and the reaction is carried out at 70°C for 5h to generate epichlorohydrin.

[0091] Example 5

[0092] The present embodiment provides a method for preparing epichlorohydrin, using hydrogen peroxide and allyl chloride as raw materials, wherein the mass ratio of hydrogen peroxide to allyl chloride is 0.1:1, under the action of the catalyst prepared in Example 2, the added amount of the catalyst is 5wt% of the allyl chloride, and the reaction is carried out at 80°C for 5h to generate epichlorohydrin.

[0093] Example 6

[0094] The present embodiment provides a method for preparing epichlorohydrin, using hydrogen peroxide and allyl chloride as raw materials, wherein the mass ratio of hydrogen peroxide to allyl chloride is 0.1:1, under the action of the catalyst prepared in Example 3, the added amount of the catalyst is 5wt% of the allyl chloride, and the reaction is carried out at 75°C for 5h to generate epichlorohydrin.

[0095] Comparative Example 6

[0096] Compared with Example 6, the difference is that the catalyst is prepared by Comparative Example 1.

[0097] Comparative Example 7

[0098] Compared with Example 6, the difference is that the catalyst is prepared by Comparative Example 2.

[0099] Comparative Example 8

[0100] Compared with Example 6, the difference is that the catalyst is prepared by Comparative Example 3.

[0101] Comparative Example 9

[0102] Compared with Example 6, the difference is that the catalyst is prepared by Comparative Example 4.

[0103] Comparative Example 10

[0104] Compared with Example 6, the difference is that the catalyst is prepared by Comparative Example 5.

[0105] Test Example 2

[0106] The reactions of Examples 4-6 and Comparative Examples 6-10 were evaluated and the results are shown in Table 2.

[0107] Table 2

[0108] Group Conversion rate of hydrogen peroxide (%) Selectivity of epichlorohydrin (%) Example 4 95.9 99.4 Example 5 96.2 99.5 Example 6 96.7 99.8 Comparative Example 6 91.1 92.8 Comparative Example 7 92.7 94.2 Comparative Example 8 86.5 90.8 Comparative Example 9 89.3 91.4 Comparative Example 10 90.2 88.7

[0109] As can be seen from the above table, the reaction methods in Examples 4-6 of the present invention have higher conversion rates of hydrogen peroxide and selectivity for epichlorohydrin.

[0110] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing epichlorohydrin, using hydrogen peroxide and allyl chloride as raw materials, characterized in that: Under the action of a catalyst, epichlorohydrin is generated by reaction. The catalyst is a catalyst with layered metal oxide / Al2O3 / SiO2 microspheres as carriers, loaded with K and Mo, and the surface of which is modified by phytic acid and beta-cyclodextrin.

2. The preparation method according to claim 1, characterized in that: The mass ratio of hydrogen peroxide to allyl chloride is 0.02-0.2:

1.

3. The preparation method according to claim 1, characterized in that: The reaction temperature is 70-80°C, and the reaction time is 1-5h.

4. The preparation method according to claim 1, characterized in that: The preparation method of the catalyst is as follows: S1. Preparation of porous Al2O3 / SiO2 microspheres: Alkyl orthosilicate and aluminum isopropoxide were dissolved in ethanol, porogen, ammonia and water were added, stirred for reaction, centrifuged, washed, dried and calcined to obtain porous Al2O3 / SiO2 microspheres; S2. Deposition of layered metal oxides: Dissolve zinc nitrate, iron nitrate and nickel nitrate in water, add alkali solution, add porous Al2O3 / SiO2 microspheres, heat for crystallization, filter, wash, dry and calcine to obtain layered metal oxide / Al2O3 / SiO2 microspheres; S3. Impregnation: potassium carbonate and ammonium molybdate were dissolved in water to prepare an impregnation solution, layered metal oxide / Al2O3 / SiO2 microspheres were added, and the solvent was evaporated to obtain a mixture; S4 Calcination: The mixture was calcined to obtain K / Mo- layered metal oxide / Al2O3 / SiO2 microspheres; S5. Preparation of catalyst: Add K / Mo-layered metal oxide / Al2O3 / SiO2 microspheres, phytic acid, β-cyclodextrin and potassium dihydrogen phosphate into water, perform hydrothermal reaction, filter, wash and dry to obtain a catalyst.

5. The preparation method according to claim 4, characterized in that: The alkyl orthosilicate in step S1 is methyl orthosilicate or ethyl orthosilicate, the mass ratio of the alkyl orthosilicate, aluminum isopropoxide, porogen, ammonia water and water is 12-15:7-10:2-3:5-7:10-12, the stirring reaction time is 7-10h, the calcination temperature is 400-500°C, the time is 2-4h, and the porogen is hexadecyltrimethylammonium bromide.

6. The preparation method according to claim 4, characterized in that: The mass ratio of zinc nitrate, iron nitrate, nickel nitrate and Al2O3 / SiO2 microspheres in step S2 is 3-4:5-7:1-2:10, the pH value of the solution is adjusted to 7-7.5 by dropping alkali solution, the heating crystallization temperature is 85-95°C, the time is 20-40min, the calcination temperature is 600-700°C, the time is 2-4h, and the alkali solution is 0.5-1mol / L NaOH or KOH solution.

7. The preparation method according to claim 4, characterized in that: The mass ratio of potassium carbonate, ammonium molybdate and layered metal oxide / Al2O3 / SiO2 microspheres in step S3 is 3-5:7-10:13-17.

8. The preparation method according to claim 4, characterized in that: The calcination temperature in step S4 is 600-800° C. and the calcination time is 1-3 hours.

9. The preparation method according to claim 4, characterized in that: In step S5, the mass ratio of K / Mo-layered metal oxide / Al2O3 / SiO2 microspheres, phytic acid, β-cyclodextrin, and potassium dihydrogen phosphate is 10:3-5:5-7:0.2-0.5, the temperature of the hydrothermal reaction is 130-160°C, and the time is 8-10h.

10. A catalyst used in claim 1, characterized in that The preparation method comprises the following steps: S1. Preparation of porous Al2O3 / SiO2 microspheres: 12-15 parts by weight of alkyl orthosilicate and 7-10 parts by weight of aluminum isopropoxide were dissolved in ethanol, 2-3 parts by weight of a porogen, 5-7 parts by weight of aqueous ammonia and 10-12 parts by weight of water were added, the reaction was stirred for 7-10 hours, centrifuged, washed, dried, and calcined at 400-500°C for 2-4 hours to obtain porous Al2O3 / SiO2 microspheres; S2. Deposition of layered metal oxides: 3-4 parts by weight of zinc nitrate, 5-7 parts by weight of iron nitrate, and 1-2 parts by weight of nickel nitrate were dissolved in water, 0.5-1 mol / L of NaOH or KOH solution was added dropwise to adjust the pH value of the solution to 7-7.5, 10 parts by weight of Al2O3 / SiO2 microspheres were added, heated to 85-95°C, crystallized for 20-40min, filtered, washed, dried, and calcined at 600-700°C for 2-4h to obtain layered metal oxides / Al2O3 / SiO2 microspheres; S3 impregnation: 3-5 parts by weight of potassium carbonate and 7-10 parts by weight of ammonium molybdate were dissolved in water to obtain an impregnation solution, 13-17 parts by weight of layered metal oxide / Al2O3 / SiO2 microspheres were added, and the solvent was evaporated to obtain a mixture; S4 Calcination: The mixture was calcined at 600-800 ℃ for 1-3h to obtain K / Mo- layered metal oxide / Al2O3 / SiO2 microspheres; S5. Preparation of catalyst: add 10 parts by weight of K / Mo-layered metal oxide / Al2O3 / SiO2 microspheres, 3-5 parts by weight of phytic acid, 5-7 parts by weight of β-cyclodextrin, and 0.2-0.5 parts by weight of potassium dihydrogen phosphate into water, carry out hydrothermal reaction at 130-160°C for 8-10 hours, filter, wash, and dry to obtain the catalyst.

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