A kind of synthesis method of epichlorohydrin

Abstract

The present invention discloses a method for synthesizing epichlorohydrin. The method comprises the following steps: adding 3-chloropropylene and hydrogen peroxide to a solvent, adding an inorganic base to adjust the pH, and carrying out a reaction under the catalytic action of a modified titanium silicalite. The method can achieve a hydrogen peroxide conversion rate of over 99.5%, and an epichlorohydrin selectivity of over 99%.

Description

Technical Field

[0001] The invention belongs to the field of organic synthesis, and particularly relates to a method for synthesizing epichlorohydrin. Background Art

[0002] Epichlorohydrin, also known as epichlorohydrin, is a volatile, unstable, colorless, oily liquid. It is an important organic chemical raw material, synthetic intermediate, and fine chemical product. It is widely used in the synthesis of epoxy resins, nitroglycerin explosives, epichlorohydrin rubber, glycerin, electrical insulation, surfactants, fiberglass reinforced plastics, ion exchange resins, pharmaceuticals, pesticides, plasticizers, and hydroxyethyl ester derivatives. Besides EO and PO, it is the largest epoxy monomer in terms of market volume.

[0003] The main synthesis routes for epichlorohydrin are the chlorohydrin method, the glycerin method, and the direct oxidation method with hydrogen peroxide. The chlorohydrin method produces 36 tons of high-salt wastewater per ton of epichlorohydrin, which is subject to environmental restrictions; the glycerin method has high raw material costs; and the direct oxidation method with hydrogen peroxide has low raw material costs and less waste, waste gas, and waste residue, making it the focus of current research.

[0004] Hydrogen peroxide direct oxidation uses allyl chloride and hydrogen peroxide as raw materials to synthesize epichlorohydrin in one step. The reaction equation is as follows:

[0005]

[0006] Patent CN111057026A discloses a method for synthesizing epichlorohydrin using ordinary titanium silicon molecular sieve as a catalyst. Carbonate or bicarbonate is added to the raw material, the hydrogen peroxide conversion rate is 96%, and the epichlorohydrin selectivity is about 98%.

[0007] Patent CN103030610A discloses a method for producing epichlorohydrin by oxidizing allyl chloride. The method uses a titanium silicalite molecular sieve material with a composite pore structure. The catalyst synthesis uses polyethylene glycol, polyoxyethylene or polyethylene oxide as a phase separation inducer, a triblock copolymer, an ammonium halide, citric acid, tartaric acid, malic acid or lactic acid as a structure directing agent, and ammonium fluoride, potassium fluoride, ammonium chloride, ammonium phosphate or ammonium carbonate as a catalyst. The epichlorohydrin selectivity can reach 99%, and the epichlorohydrin yield can reach 98%.

[0008] Patent CN107308981A discloses a modified titanium silicate molecular sieve catalyst, its preparation method and application, and a method for synthesizing epichlorohydrin. The modified titanium silicate molecular sieve catalyst has an MFI topology and is added with alumina and silver. Using this solution, the epichlorohydrin selectivity can reach 98% and the epichlorohydrin yield can reach 89%.

[0009] However, the above patented technologies all have the problem of low hydrogen peroxide conversion rate, and the selectivity of epichlorohydrin is still low and needs to be further improved. How to further improve the selectivity of epichlorohydrin and increase the hydrogen peroxide conversion rate is of great significance. Summary of the Invention

[0010] To solve the above problems, the present invention provides a method for synthesizing epichlorohydrin, which can significantly improve the utilization rate of hydrogen peroxide and reduce the amount of polymer generated. The conversion rate of hydrogen peroxide can reach above 99.5%, and the selectivity of epichlorohydrin can reach above 99%.

[0011] In order to achieve the above technical effects, the present invention adopts the following technical solutions:

[0012] A method for synthesizing epichlorohydrin comprises adding 3-chloropropylene and hydrogen peroxide into a solvent, adding an inorganic base to adjust the pH, and carrying out a reaction under the catalysis of a modified titanium silicalite molecular sieve.

[0013] Preferably, the modified titanium silicate molecular sieve is a titanium silicate molecular sieve modified with ammonium fluorine-containing metal oxide.

[0014] Preferably, the preparation method of the titanium silicalite molecular sieve modified with ammonium fluorine-containing metal oxide is as follows:

[0015] 1) uniformly mixing titanium silicon molecular sieve powder, fluorine-containing ammonium metal acid, silica sol and pore-enlarging agent, and forming;

[0016] 2) The formed catalyst is placed in a muffle furnace at 500-600° C. and calcined for 10-12 hours to obtain a titanium silicate molecular sieve catalyst modified with ammonium fluorine-containing metal oxide.

[0017] Preferably, the fluorine-containing ammonium metal acid salt includes but is not limited to ammonium fluorotitanate, ammonium fluorosilicate, ammonium fluoroferrate, ammonium fluoroaluminate, ammonium fluorozirconate, ammonium fluoroberyllate, ammonium fluoroniobate, ammonium fluororuthenate, ammonium fluorovanadate, ammonium fluorothalliumate, ammonium fluoroantimonate, and ammonium fluorogallate, preferably ammonium fluorogallate and ammonium fluorozirconate. The amount of the fluorine-containing ammonium metal acid salt used is 1-5% by mass of the titanium silicalite raw powder, preferably 2-3%.

[0018] Preferably, the silica sol is a silica aqueous solution with a silica concentration of 20-25%. The amount of silica sol used is 0.3-2 times, preferably 0.5-1.5 times, the mass of the titanium silicate molecular sieve powder.

[0019] The pore expanding agent includes sesbania powder, ethanol, yeast, carbon black, mesitylene, polyethylene glycol, urea, boric acid, polyacrylamide, acetic acid, oxalic acid, adipic acid, formic acid, citric acid, salicylic acid, tartaric acid, benzoic acid, and starch, preferably sesbania powder. The amount of the pore expanding agent is 1-10% of the mass of the original titanium silicalite powder, preferably 2-3%.

[0020] Preferably, a polymerization inhibitor is added to the reaction, and the polymerization inhibitor is a piperidine nitroxide free radical polymerization inhibitor. The piperidine nitroxide free radical includes but is not limited to p-hydroxytetramethylpiperidine nitroxide free radical (ZJ-701), 4-carbonyl-tetramethylpiperidine nitroxide free radical (ZJ-702), and tetramethylpiperidine nitroxide free radical phosphite (ZJ-705), preferably p-hydroxytetramethylpiperidine nitroxide free radical and tetramethylpiperidine nitroxide free radical phosphite; the amount of the polymerization inhibitor is 0.1-1% of the mass of 3-chloropropylene, preferably 0.2-0.3%.

[0021] In the present invention, the amount of inorganic base added is based on adjusting the pH of the reaction solution to 7-8. The inorganic base includes one or more of sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, cesium hydroxide, ammonia water, potassium carbonate, sodium bicarbonate, sodium carbonate, cesium fluoride, and cesium carbonate, preferably ammonia water. The concentration of ammonia water can be selected from 10-50%, preferably 25-28%.

[0022] In the present invention, the solvent includes one or more of methanol, ethanol, n-propanol, isopropanol, acetone, n-butanol, isobutanol, tert-butanol, butanone, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, and glycerol, preferably methanol.

[0023] In the present invention, the mass space velocity of 3-chloropropylene is 1 to 3 h -1 The molar ratio of hydrogen peroxide to 3-chloropropylene is 0.2-0.5:1, the molar ratio of solvent to 3-chloropropylene is 4-6:1, and the mass concentration of hydrogen peroxide is 30-70%.

[0024] The reaction temperature of the present invention can be selected from 20 to 70° C., preferably from 30 to 60° C., and the operating pressure is from 10 KPa(G) to 200 KPa(G).

[0025] The synthesis method of the present invention can significantly improve the utilization rate of hydrogen peroxide and the selectivity of epichlorohydrin. The mechanism is speculated as follows: the present invention uses a titanium silicalite modified with fluorine-containing ammonium metal acid as a catalyst. The fluorine atoms have strong polarity and can form hydrogen bonds with the hydrogen atoms of hydrogen peroxide. After the addition of the fluorine-containing ammonium metal acid to the titanium silicalite, the utilization rate of hydrogen peroxide can be greatly improved. The fluorine-containing ammonium metal acid contains metal atoms, which can produce a coordination effect with the chlorine atoms of allyl chloride, thereby improving the utilization rate of allyl chloride. At the same time, the present invention uses piperidine nitroxide free radicals as a polymerization inhibitor. The nitroxide free radicals of the polymerization inhibitor can complex with the metal atoms of the fluorine-containing ammonium metal acid, synergistically preventing the occurrence of polymerization during the reaction process. The method of the present invention can significantly improve the utilization rate of hydrogen peroxide and reduce the amount of polymer produced. The conversion rate of hydrogen peroxide can reach above 99.5%, and the selectivity of epichlorohydrin can reach above 99% (based on the theoretical production of 1 mol of hydrogen peroxide to 1 mol of epichlorohydrin). DETAILED DESCRIPTION

[0026] The present invention is further described below with reference to the following examples. It should be noted that the examples do not limit the scope of protection claimed in the present invention.

[0027] The detection method used in the embodiment is introduced below:

[0028] (1) HPLC method

[0029] The present invention uses high performance liquid chromatography to analyze the conversion rate of 3-chloropropene and epichlorohydrin selectivity. The chromatographic analysis conditions are as follows:

[0030] Instrument model: LC-6A high performance liquid chromatograph (Shimadzu)

[0031] Analytical column: CLC-SIL 150*6.0mm (Shimadzu)

[0032] Preparative column: Zorbax SIL 250*9.4mm (Zhubang)

[0033] Mobile phase: ether: ethanol: tert-butanol: cyclohexane = 10:3:3:55 (v / v)

[0034] Flow rate: 0.8ml / min

[0035] Column temperature: room temperature

[0036] UV detector (Shimadzu SPD-6AV UV-visible spectrophotometer) wavelength: 240 nm

[0037] (2) Potentiometric titration

[0038] The present invention adopts KMnO4 direct titration method to analyze the hydrogen peroxide content, using Swiss Metrohm 905 Ai·Intelligent series fully automatic potentiometric titrator.

[0039] Source of raw materials:

[0040] Raw material name Manufacturer Titanium silicate molecular sieve powder China Catalyst New Materials Co., Ltd. Ammonium fluorogallate Beijing Bailingwei Technology Co., Ltd. Ammonium fluozirconate Shandong Changyao New Materials Co., Ltd. Ammonium fluorotitanate Shandong Liang New Material Technology Co., Ltd. ZJ-701 Shandong Lingchuang Biotechnology Co., Ltd. ZJ-702 Nantong Runfeng Petrochemical Co., Ltd. ZJ-705 Jiangsu Xinsu New Materials Co., Ltd.

[0041] Example 1

[0042] Preparation of Catalyst-A:

[0043] 1) Mix 20 g of titanium silicate molecular sieve powder, 0.2 g of ammonium fluorogallate, 6 g of a 25% silica sol aqueous solution, and 0.2 g of sesbania powder, and squeeze into strips;

[0044] 2) The extruded catalyst was placed in a muffle furnace at 600° C. and calcined for 10 h. The ammonium fluorogallate-modified titanium silicate molecular sieve catalyst-A was obtained after pelletizing.

[0045] Preparation of epichlorohydrin:

[0046] A method for preparing epichlorohydrin comprises the following steps:

[0047] 1) 10 g of catalyst-A was loaded into a fixed bed;

[0048] 2) Mix 1000 g of 3-chloropropylene, 296 g of 30% hydrogen peroxide, 1675 g of methanol, and 1 g of ZJ-701, and adjust the pH of the reaction solution to 7 with 25% ammonia water;

[0049] 3) The fixed bed was heated to 20°C and pressurized to 10 kPa(G), and the feed reaction was started at a feed rate of 30 g / h of the raw material mixture.

[0050] After 100 hours of continuous reaction, the reaction liquid was analyzed, and the conversion rate of hydrogen peroxide was 99.73%, and the selectivity of epichlorohydrin was 99.86%.

[0051] Example 2

[0052] Preparation of Catalyst-B:

[0053] 1) Mix 20 g of titanium silicate molecular sieve powder, 1 g of ammonium fluorozirconate, 40 g of a 20% silica sol aqueous solution, and 2 g of sesbania powder, and squeeze into strips;

[0054] 2) The extruded catalyst was placed in a muffle furnace at 500° C. and calcined for 12 h. The ammonium fluorozirconate-modified titanium silicate molecular sieve catalyst-B was obtained after pelletizing.

[0055] Preparation of epichlorohydrin:

[0056] A method for preparing epichlorohydrin comprises the following steps:

[0057] 1) 10 g of catalyst-B was loaded into a fixed bed;

[0058] 2) Mix 1000 g of 3-chloropropylene, 317 g of 70% hydrogen peroxide, 2512 g of methanol, and 10 g of ZJ-705, and adjust the pH of the reaction solution to 8 with 28% ammonia water;

[0059] 3) The fixed bed was heated to 70°C and pressurized to 200 kPa(G), and the feed reaction was started at a feed rate of 115 g / h of the raw material mixture.

[0060] After 100 hours of continuous reaction, the reaction liquid was analyzed, and the conversion rate of hydrogen peroxide was 99.76%, and the selectivity of epichlorohydrin was 99.79%.

[0061] Example 3

[0062] Preparation of Catalyst-C:

[0063] 1) Mix 20 g of titanium silicate molecular sieve powder, 0.6 g of ammonium fluorotitanate, 20 g of a 23% silica sol aqueous solution, and 1 g of sesbania powder, and squeeze into strips;

[0064] 2) The extruded catalyst was calcined in a muffle furnace at 550° C. for 11 h, and pelletized to obtain ammonium fluorotitanate-modified titanium silicate molecular sieve catalyst-C.

[0065] Preparation of epichlorohydrin:

[0066] A method for preparing epichlorohydrin comprises the following steps:

[0067] 1) 10 g of catalyst-C was loaded into a fixed bed;

[0068] 2) Mix 1000 g of 3-chloropropylene, 267 g of 50% hydrogen peroxide, 2094 g of methanol, and 3 g of ZJ-702, and adjust the pH of the reaction solution to 7.5 with 26% ammonia water;

[0069] 3) The fixed bed was heated to 40°C and pressurized to 50 kPa(G), and the feed reaction was started at a feed rate of 67 g / h of the raw material mixture.

[0070] After 100 hours of continuous reaction, the reaction liquid was analyzed, and the conversion rate of hydrogen peroxide was 99.55%, and the selectivity of epichlorohydrin was 99.64%.

[0071] Example 4

[0072] 1) 10 g of catalyst-A prepared according to the method of Example 1 was loaded into a fixed bed;

[0073] 2) Mix 1000 g of 3-chloropropylene, 296 g of 30% hydrogen peroxide, and 1675 g of methanol, and adjust the pH of the reaction solution to 7 with 25% ammonia water;

[0074] 3) The fixed bed was heated to 20°C and pressurized to 10 kPa(G), and the feed reaction was started at a feed rate of 30 g / h of the raw material mixture.

[0075] After 100 hours of continuous reaction, the reaction liquid was analyzed, and the conversion rate of hydrogen peroxide was 97.43%, and the selectivity of epichlorohydrin was 97.19%.

[0076] Comparative Example 1

[0077] Preparation of Catalyst-D:

[0078] 1) Mix 20 g of titanium silicate molecular sieve powder, 6 g of 25% silica sol aqueous solution, and 0.2 g of sesbania powder, and squeeze into strips;

[0079] 2) The extruded catalyst was calcined in a muffle furnace at 600° C. for 10 h, and pelletized to obtain titanium silicate molecular sieve catalyst-D.

[0080] Preparation of epichlorohydrin:

[0081] 1) 10 g of catalyst-D was loaded into a fixed bed;

[0082] 2) Mix 1000 g of 3-chloropropylene, 296 g of 30% hydrogen peroxide, 1675 g of methanol, and 1 g of ZJ-701, and adjust the pH of the reaction solution to 7 with 25% ammonia water;

[0083] 3) The fixed bed was heated to 20°C and pressurized to 10 kPa(G), and the feed reaction was started at a feed rate of 30 g / h of the raw material mixture.

[0084] After 100 hours of continuous reaction, the reaction liquid was analyzed, and the conversion rate of hydrogen peroxide was 94.11%, and the selectivity of epichlorohydrin was 97.03%.

[0085] Comparative Example 2

[0086] 1) 10 g of catalyst-D was loaded into a fixed bed;

[0087] 2) Mix 1000 g of 3-chloropropylene, 296 g of 30% hydrogen peroxide, and 1675 g of methanol, and adjust the pH of the reaction solution to 7 with 25% ammonia water;

[0088] 3) The fixed bed was heated to 20°C and pressurized to 10 kPa(G), and the feed reaction was started at a feed rate of 30 g / h of the raw material mixture.

[0089] After 100 hours of continuous reaction, the reaction liquid was analyzed, and the conversion rate of hydrogen peroxide was 92.85%, and the selectivity of epichlorohydrin was 94.34%.

[0090] Comparative Example 3

[0091] 1) Place 10g of TS-1 from the Institute of Petroleum Technology into the fixed bed;

[0092] 2) Mix 1000 g of 3-chloropropylene, 296 g of 30% hydrogen peroxide, and 1675 g of methanol, and adjust the pH of the reaction solution to 7 with 25% ammonia water;

[0093] 3) The fixed bed was heated to 20°C and pressurized to 10 kPa(G), and the feed reaction was started at a feed rate of 30 g / h of the raw material mixture.

[0094] After 100 hours of continuous reaction, the reaction liquid was analyzed and the conversion rate of hydrogen peroxide was 91.44% and the selectivity of epichlorohydrin was 93.79%.

Claims

1. A method for synthesizing epichlorohydrin, characterized in that: 3-chloropropylene and hydrogen peroxide are added to a solvent, an inorganic base is added to adjust the pH value of the reaction solution to 7-8, and the reaction is carried out under the catalysis of a modified titanium silicalite molecular sieve; The preparation method of the modified titanium silicate molecular sieve is as follows: 1) uniformly mixing titanium silicon molecular sieve powder, fluorine-containing ammonium metal acid, silica sol and pore-enlarging agent, and forming; 2) calcining the formed catalyst in a muffle furnace at 500-600° C. for 10-12 hours to obtain a modified titanium silicate molecular sieve catalyst; The fluorine-containing ammonium metal acid salt is selected from one or more of ammonium fluoroferrate, ammonium fluoroaluminate, ammonium fluorozirconate, ammonium fluoroberyllate, ammonium fluoroniobate, ammonium fluororuthenate, ammonium fluorovanadate, ammonium fluorothalliumate, ammonium fluoroantimonate, and ammonium fluorogallate.

2. The synthesis method according to claim 1, wherein The fluorine-containing ammonium metal acid salts are ammonium fluorogallate and ammonium fluorozirconate.

3. The synthesis method according to claim 1, wherein The amount of the fluorine-containing ammonium metal acid salt is 1-5% of the mass of the original titanium silicon molecular sieve powder.

4. The synthesis method according to claim 3, characterized in that The amount of the fluorine-containing ammonium metal acid salt is 2-3% of the mass of the original titanium silicon molecular sieve powder.

5. The synthesis method according to claim 1, characterized in that The silica sol is a silicon dioxide aqueous solution with a silicon dioxide concentration of 20-25%. The amount of the silica sol used is 0.3-2 times the mass of the original titanium silicon molecular sieve powder.

6. The synthesis method according to claim 5, characterized in that The amount of the silica sol used is 0.5 to 1.5 times the mass of the original titanium silicate molecular sieve powder.

7. The synthesis method according to claim 1, characterized in that The pore expanding agent is selected from sesbania powder, ethanol, yeast, carbon black, mesitylene, polyethylene glycol, urea, boric acid, polyacrylamide, acetic acid, oxalic acid, adipic acid, formic acid, citric acid, salicylic acid, tartaric acid, benzoic acid, and starch. The amount of the pore expanding agent is 1-10% of the mass of the original titanium silicate molecular sieve powder.

8. The synthesis method according to claim 7, characterized in that The pore-enlarging agent is sesbania powder, And / or, the amount of the pore-enlarging agent is 2-3% of the mass of the original titanium silicate molecular sieve powder.

9. The synthesis method according to any one of claims 1 to 8, characterized in that A polymerization inhibitor is also added into the reaction, and the polymerization inhibitor is a piperidine-type nitrogen oxide free radical polymerization inhibitor.

10. The synthesis method according to claim 9, characterized in that The piperidine nitroxide free radical is selected from hydroxytetramethylpiperidine nitroxide free radical, 4-carbonyl-tetramethylpiperidine nitroxide free radical, tetramethylpiperidine nitroxide free radical phosphite, and the amount of the polymerization inhibitor is 0.1-1% of the mass of 3-chloropropylene.

11. The synthesis method according to claim 10, characterized in that The piperidine nitroxide free radicals are p-hydroxytetramethylpiperidine nitroxide free radical and tetramethylpiperidine nitroxide free radical phosphite; And / or, the amount of the polymerization inhibitor is 0.2 to 0.3% of the mass of 3-chloropropylene.

12. The synthesis method according to claim 1, characterized in that The inorganic base is selected from one or more of sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, cesium hydroxide, ammonia water, potassium carbonate, sodium bicarbonate, sodium carbonate, cesium fluoride, and cesium carbonate.

13. The synthesis method according to claim 12, characterized in that The inorganic base is aqueous ammonia.

14. The synthesis method according to claim 1, characterized in that The solvent is selected from one or more of methanol, ethanol, n-propanol, isopropanol, acetone, n-butanol, isobutanol, tert-butanol, butanone, ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, and glycerol.

15. The synthesis method according to claim 14, characterized in that The solvent is methanol.

16. The synthesis method according to claim 11, characterized in that The mass space velocity of 3-chloropropene is 1 to 3 h -1 The molar ratio of hydrogen peroxide to 3-chloropropylene is 0.2-0.5:1, the molar ratio of solvent to 3-chloropropylene is 4-6:1, and the mass concentration of hydrogen peroxide is 30-70%.

17. The synthesis method according to claim 1, characterized in that The reaction temperature is 20-70°C, and the operating pressure is 10KPaG-200KPaG.

18. The synthesis method according to claim 17, characterized in that The reaction temperature is 30-60°C.

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