A residue-reducing and environmentally friendly propylene oxide saponification reaction method

Abstract

The present application relates to a kind of residue reduction environmental protection's epoxy propane saponification reaction method.The method includes: chlorohydrin occurs epoxidation in the presence of alkali, obtains epoxy propane;Wherein, the average particle size D of the alkali≤1000 μm.The method of the present application significantly improves the saponification reaction and the production efficiency of epoxy propane, and can significantly reduce the amount of calcium hydroxide and solid waste production, with significant economic advantage and environmental advantage.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of residue reduction environmental protection epoxide propane saponification reaction method, belong to the energy-saving and environment-friendly chemical process field. BACKGROUND

[0002] Among numerous chemical products, propylene derivatives occupy an important position. Among these derivatives, the production of propylene oxide (PO) is particularly prominent, ranking second only to polypropylene and acrylonitrile, becoming one of the important varieties of propylene derivatives. As an important organic chemical raw material, propylene oxide is widely used in the production process of polyurethane, surfactant, propylene glycol and other chemical products. Its market demand is large, and its application field is wide, so propylene oxide occupies a pivotal position in the global chemical industry. With the continuous progress of chemical technology and the sustained growth of market demand, the production and application prospect of propylene oxide will continue to maintain strong development momentum.

[0003] Currently, the main methods for industrial synthesis of propylene oxide include chlorohydrination, ethylbenzene co-oxidation, isobutane co-oxidation, and hydrogen peroxide direct oxidation (HPPO). Among them, chlorohydrination is a relatively mature process, which generates chlorohydrin from chlorinated propylene, and then obtains propylene oxide by dehydrochlorination, but this method produces a large amount of waste residue, causing environmental pollution. Ethylbenzene co-oxidation is a method of generating propylene oxide by co-oxidation of ethylbenzene and oxygen. Although this method reduces the generation of waste residue, it has high energy consumption, and the toxicity of ethylbenzene also poses a threat to the environment and the health of operating personnel. Isobutane co-oxidation is a method of generating propylene oxide from isobutane and oxygen under the action of a catalyst. This method has many by-products, and the purity of the raw material isobutane is required to be high. Hydrogen peroxide direct oxidation is a method of generating propylene oxide by direct reaction of hydrogen peroxide and propylene. The only by-product of this method is water, and it is an environmentally friendly production method, but the technology is not mature enough and the cost is high.

[0004] The present application aims to provide a lime milk for propylene oxide production and its use, in order to improve the efficiency of saponification reaction in propylene oxide production. SUMMARY

[0005] To improve the above technical problems, the present application provides a method for saponification reaction, which comprises: epoxidation of chlorohydrin in the presence of alkali to obtain propylene oxide; wherein the average particle size D of the alkali is ≤1000 μm.

[0006] According to embodiments of the present application, the average particle size D of the base is selected from the group consisting of 10-1000 μιη, for example 15-500 μιη, such as 20-250 μιη, 25-200 μιη, 30-150 μιη, 40-100 μιη. By way of example, D can be 10 μιη, 15 μιη, 20 μιη, 25 μιη, 30 μιη, 35 μιη, 40 μιη, 45 μιη, 50 μιη, 55 μιη, 60 μιη, 65 μιη, 70 μιη, 75 μιη, 80 μιη, 85 μιη, 90 μιη, 95 μιη, 100 μιη, 150 μιη or 200 μιη.

[0007] According to embodiments of the present application, the base can comprise an inorganic base known in the art to be useful in saponification reactions, which can be selected from the group consisting of one or more of Ca(OH)2, CaCO3, CaO, Mg(OH)2, MgCO3, NaOH, Na2CO3, NaHCO3, including but not limited to.

[0008] Preferably, the average particle size D of the Ca(OH)2or CaO is selected from the group consisting of 10-1000 μιη, for example 15-500 μιη, such as 20-250 μιη, 25-200 μιη, 30-150 μιη, 40-100 μιη. By way of example, D can be 10 μιη, 15 μιη, 20 μιη, 25 μιη, 30 μιη, 35 μιη, 40 μιη, 45 μιη, 50 μιη, 55 μιη, 60 μιη, 65 μιη, 70 μιη, 75 μιη, 80 μιη, 85 μιη, 90 μιη, 95 μιη, 100 μιη, 150 μιη or 200 μιη.

[0009] According to embodiments of the present application, the base (e.g. Ca(OH)2or CaO) has a purity of no less than 90%, for example 90-95%.

[0010] According to embodiments of the present application, the base is reacted with the chlorohydrin in the form of a mixture thereof with water. For example, a mixture of Ca(OH)2or CaO with water is reacted with the chlorohydrin. In some embodiments, the water is provided from a concentrate solution as described below.

[0011] According to embodiments of the present application, the chlorohydrin can be a chloropropanol selected from the group consisting of 1-chloro-2-propanol, 2-chloro-1-propanol or mixtures thereof.

[0012] According to embodiments of the present application, the chlorohydrin can be reacted with the base in the form of a propene chlorohydrination reaction product.

[0013] According to embodiments of the present application, the temperature of the saponification reaction (i.e. the kettle temperature) can range from 80-95°C, for example 85-86°C.

[0014] According to embodiments of the present application, in the saponification reaction, when 1 mole of the base (e.g. Ca(OH)2, CaCO3, CaO, Mg(OH)2, MgCO3, Na2CO3) can react with 2 moles of H + The molar ratio of the base to chlorohydrin in the reaction can range from 1.05 to 1.20. Alternatively, when 1 mole of the base (e.g. NaOH, NaHCO3) can react with 1 mole of H + The molar ratio of the base to chlorohydrin in the reaction can range from 2.10 to 2.40.

[0015] The present application also provides a mixture comprising a mixture of the base and water as described above. In the mixture, the concentration of the base can be 5% to 10% by weight (calculated as OH - In some embodiments, the water is provided by the concentrated solution.

[0016] The present application also provides a method for producing propylene oxide, comprising the method of the saponification reaction described above.

[0017] According to embodiments of the present application, the method for producing propylene oxide further comprises a propylene chlorohydrination reaction, wherein the product of the propylene chlorohydrination reaction is subjected to the saponification reaction with the base to obtain propylene oxide.

[0018] According to embodiments of the present application, the method for producing propylene oxide comprises:

[0019] saponification of chloropropanol in a system to obtain propylene oxide;

[0020] The system comprises lime milk, chlorohydrin solution, concentrated solution, and reaction materials of the concentrated solution and chlorohydrin.

[0021] The concentrated solution is obtained by concentrating the saponification residual solution generated in the saponification reaction, for example, by using sedimentation or centrifugation.

[0022] According to embodiments of the present application, the concentration ratio of the saponification residual solution to the concentrated solution is 1:1.05 to 1:8, for example, 1:1.1, 1:1.2, 1:1.3, 1:1.5, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7.

[0023] According to embodiments of the present application, the chlorohydrin solution is the reaction solution after the chlorohydrination reaction of propylene with chlorine and water.

[0024] According to embodiments of the present application, the concentrated solution (i.e. the concentrated saponification residual solution) accounts for 70% to 99% of the total volume of the saponification residual solution, for example, 75%, 80%, 85%, 90%, 92%, 95%.

[0025] According to embodiments of the present application, the saponification reaction produces a partially saponified residual liquor which is acidified to neutralize the calcium hydroxide therein. For example, hydrochloric acid is added in an amount such that it reacts only with the calcium hydroxide and not with the calcium carbonate. Preferably, the pH of the saponification residual liquor after mixing with the hydrochloric acid is between 8.6 and 9.6 to avoid the release of greenhouse gas CO2.

[0026] According to embodiments of the present application, the flow rate ratio of the saponification residual liquor which is acidified to the saponification residual liquor which is separated by sedimentation is between 1 :3 and 1 :8, for example 1 :4, 1 :5, 1 :6, 1 :7.

[0027] According to some embodiments of the present application, the calcium hydroxide content of the saponification residual liquor is between 0.1 and 0.2% and the calcium carbonate content is between 0.2 and 0.5%; and / or, the calcium hydroxide content of the concentrated liquor is between 0.5 and 1.5% and the calcium carbonate content is between 1 and 5%.

[0028] According to embodiments of the present application, the solid particulate matter in the saponification residual liquor can comprise one, two or more of an oxide, a hydroxide, a carbonate or a hydrochloric acid insoluble of a metal or a non-metal element.

[0029] According to embodiments of the present application, the metal or non-metal element can be selected from one, two or more of Ca, Mg, Fe, Al, Si.

[0030] According to embodiments of the present application, the solid particulate matter in the saponification residual liquor can comprise one, two or more of Ca(OH)2, CaCO3, MgCO3, Fe2O3, Al2O3, SiO2. For example, the filter residue can comprise Ca(OH)2, CaCO3, Mg(OH)2, MgCO3, Fe2O3, Al2O3and SiO2.

[0031] According to embodiments of the present application, the solid particulate matter in the saponification residual liquor can also comprise CaSO4.

[0032] According to embodiments of the present application, in the concentration process, the ratio of the amount of concentrated liquor recycled to the overflow of supernatant can be between 1 :3 and 1 :10, for example 1 :3, 1 :4, 1 :5, 1 :6, 1 :7, 1 :8, 1 :9 or 1 :10.

[0033] According to embodiments of the present application, the molar ratio of Ca(OH)2to chloropropanol is higher than 1 : 1 and lower than 1.5: 1, for example (1.05-1.3): 1, for example 1.05: 1, 1.10: 1, 1.15: 1, 1.20: 1, 1.25: 1 or 1.30: 1.

[0034] According to an embodiment of the present application, the flow ratio of the concentrated solution to the chlorohydrin solution can be 1:5-1:20, such as 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19, 1:20.

[0035] According to an embodiment of the present application, the method for producing propylene oxide further comprises: subjecting the saponification residual liquid after acidification treatment to solid-liquid separation, and sending the same to industrial water treatment and waste residue treatment.

[0036] According to an embodiment of the present application, the method for producing propylene oxide further comprises: sending other concentrated solutions (concentrated solutions other than the concentrated solution prepared for lime milk, the concentrated solution reacted with chlorohydrin, and the concentrated solution returned to the system) and / or concentrated pool supernatant to industrial water treatment.

[0037] Advantages

[0038] The method of the present application significantly improves the saponification reaction and the production efficiency of propylene oxide, and can significantly reduce the amount of calcium hydroxide and the amount of solid waste, thereby having significant economic and environmental advantages. DETAILED DESCRIPTION

[0039] The technical solutions of the present application will be further described in detail below in combination with specific examples. It should be understood that the following examples are only illustratively described and explained, and should not be interpreted as limiting the scope of protection of the present application. Any technology realized based on the above description of the present application is covered within the scope of protection intended by the present application.

[0040] Example 1: Preparation of lime milk

[0041] In the lime milk preparation device, the same batch of Ca(OH)2 / CaO with a purity of 92% was sieved and ground to obtain samples 1-5 with different average particle sizes.

[0042] Samples 1-5 were respectively added to the lime milk preparation device in an amount of 0.2% of the Ca(OH)2 content in the saponification residual liquid generated by the saponification reaction, and mixed with the concentrated solution to obtain lime milk. The concentrated solution was obtained by concentrating the saponification residual liquid, and the concentration ratio was 1:6. The composition of the concentrated solution was: calcium hydroxide 0.7%, calcium carbonate 2.6%. The mass percentage concentration of Ca(OH)2 in the lime milk was 7wt%, calculated as OH - counted as OH

[0043]

[0044]

[0045] Example 2: Saponification reaction experiment

[0046] In the saponification tower, the chlorohydrin solution (addition amount A) and the lime milk sample of Example 1 (addition amount B) are added into the saponification reaction device through the feeding port, the kettle temperature of the saponification reaction device is controlled at 85-86 DEG C to carry out saponification reaction, and propylene oxide is prepared, the saponification kettle temperature is Tf, and the top temperature is Td.

[0047] The chlorohydrin solution comprises 4.05 wt% chlorohydrin, 1.68 wt% HCl and the rest is water, and the chlorohydrin is a mixture of 1-chloro-2-propanol and 2-chloro-1-propanol.

[0048]

[0049] In conclusion, the production device improves the saponification reaction and the production efficiency of propylene oxide, can significantly reduce the amount of alkali and the amount of solid waste, and has significant economic advantages and environmental advantages.

[0050] The above has exemplarily described the implementation manners of the technical scheme of the present application. It should be understood that the protection scope of the present application is not limited to the above implementation manners. Any modification, equivalent replacement, improvement, etc. made by the person skilled in the art within the spirit and principle of the present application shall be included in the protection scope of the claims of the present application.

Claims

1. A method for a saponification reaction, characterized in that, The method includes: epoxidation of chlorohydrin in the presence of a base to obtain propylene oxide; wherein the average particle size D of the base is 50~200 μm; The alkali is selected from one or both of Ca(OH)2 and CaO; The purity of the alkali is not less than 90%; The alkali reacts with chlorohydrin in the form of a mixture with the concentrated solution, wherein the concentrated solution is obtained by concentrating the saponification residue produced by the saponification reaction; the concentrated solution contains 0.5-1.5% calcium hydroxide and 1-5% calcium carbonate. The temperature range of the saponification reaction is 80~86℃.

2. The method according to claim 1, characterized in that, The average particle size D of the alkali is selected from 55~150μm; And / or, the purity of the alkali is 90-95%.

3. The method according to claim 1, characterized in that, The alkali is Ca(OH)2 or CaO.

4. The method according to claim 1, characterized in that, The concentration ratio of saponification residue to concentrate is 1:1.05 to 1:8; And / or, chlorohydrin solution is the reaction solution after the reaction products of propylene with chlorine and water undergo chlorohydrination.

5. The method according to claim 1, characterized in that, The saponification reaction is carried out at a temperature range of 85~86℃. And / or, in the saponification reaction, when 1 mole of the alkali can react with 2 moles of H... + During the reaction, the molar ratio of the base to chlorohydrin ranges from 1.05 to 1.20; or, when 1 mole of the base can react with 1 mole of H+... + During the reaction, the molar ratio of the base to chlorohydrin ranges from 2.10 to 2.

40.

6. The method according to claim 1, characterized in that, The method is selected from any of the following: Method 1: In a lime milk preparation device, 92% pure Ca(OH)2 is screened and ground to obtain Ca(OH)2 with an average particle size D of 193μm; Ca(OH)2 is added to the lime milk preparation device at a concentration of 0.2% of the Ca(OH)2 content in the saponification residue produced by the saponification reaction, and mixed with the concentrate to obtain lime milk; The concentrated solution was obtained by concentrating saponification residue at a concentration ratio of 1:

6. The concentrated solution composition was: 0.7% calcium hydroxide and 2.6% calcium carbonate. The lime slurry contained 7 wt% Ca(OH)₂. - count; In the saponification tower, chlorohydrin solution at 39.99 t / tPO and lime slurry at 1.500 t / tPO are added to the saponification reactor through the feed inlet. The saponification reaction is carried out by controlling the reactor temperature at 85.4℃ and the top temperature at 72.6℃ to prepare propylene oxide. The chlorohydrin solution contains 4.05 wt% chlorohydrin, 1.68 wt% HCl and the balance being water, wherein the chlorohydrin is a mixture of 1-chloro-2-propanol and 2-chloro-1-propanol; Method 2: In the lime milk preparation device, 92% pure Ca(OH)2 is screened and ground to obtain Ca(OH)2 with an average particle size D of 150μm; Ca(OH)2 is added to the lime milk preparation device at a content of 0.2% of Ca(OH)2 in the saponification residue produced by the saponification reaction, and mixed with the concentrate to obtain lime milk; The concentrated solution was obtained by concentrating saponification residue at a concentration ratio of 1:

6. The concentrated solution composition was: 0.7% calcium hydroxide and 2.6% calcium carbonate. The lime slurry contained 7 wt% Ca(OH)₂. - count; In the saponification tower, chlorohydrin solution at 39.98 t / tPO and lime slurry at 1.495 t / tPO are added to the saponification reactor through the feed inlet. The saponification reaction is carried out by controlling the reactor temperature at 85.3℃ and the top temperature at 72.5℃ to prepare propylene oxide. The chlorohydrin solution contains 4.05 wt% chlorohydrin, 1.68 wt% HCl and the balance being water, wherein the chlorohydrin is a mixture of 1-chloro-2-propanol and 2-chloro-1-propanol; Method 3: In the lime milk preparation device, 92% pure Ca(OH)2 is screened and ground to obtain Ca(OH)2 with an average particle size D of 74μm; Ca(OH)2 is added to the lime milk preparation device at a content of 0.2% of Ca(OH)2 in the saponification residue produced by the saponification reaction, and mixed with the concentrate to obtain lime milk; The concentrated solution was obtained by concentrating saponification residue at a concentration ratio of 1:

6. The concentrated solution composition was: 0.7% calcium hydroxide and 2.6% calcium carbonate. The lime slurry contained 7 wt% Ca(OH)₂. - count; In the saponification tower, chlorohydrin solution at 39.97 t / tPO and lime slurry at 1.489 t / tPO are added to the saponification reactor through the feed inlet. The saponification reaction is carried out by controlling the reactor temperature at 85.2℃ and the top temperature at 72.3℃ to prepare propylene oxide. The chlorohydrin solution contains 4.05 wt% chlorohydrin, 1.68 wt% HCl and the balance being water, wherein the chlorohydrin is a mixture of 1-chloro-2-propanol and 2-chloro-1-propanol; Method 4: In the lime milk preparation device, 92% pure Ca(OH)2 is screened and ground to obtain Ca(OH)2 with an average particle size D of 51μm; Ca(OH)2 is added to the lime milk preparation device at a content of 0.2% of Ca(OH)2 in the saponification residue produced by the saponification reaction, and mixed with the concentrate to obtain lime milk; The concentrated solution was obtained by concentrating saponification residue at a concentration ratio of 1:

6. The concentrated solution composition was: 0.7% calcium hydroxide and 2.6% calcium carbonate. The lime slurry contained 7 wt% Ca(OH)₂. - count; In the saponification tower, chlorohydrin solution at 39.96 t / tPO and lime slurry at 1.485 t / tPO are added to the saponification reactor through the feed inlet. The saponification reaction is carried out by controlling the reactor temperature at 85.1℃ and the top temperature at 72.1℃ to prepare propylene oxide. The chlorohydrin solution contains 4.05 wt% chlorohydrin, 1.68 wt% HCl and the balance being water. The chlorohydrin is a mixture of 1-chloro-2-propanol and 2-chloro-1-propanol.

7. A method for producing propylene oxide, characterized in that, The production method includes the saponification reaction method according to any one of claims 1-6.

8. The production method according to claim 7, characterized in that, The method for producing propylene oxide further includes a propylene chlorohydrin reaction, wherein the product of the propylene chlorohydrin reaction is saponified with the alkali to obtain propylene oxide.

9. The production method according to claim 7, characterized in that, The method for producing propylene oxide includes: Chloropropanol undergoes a saponification reaction in the system to yield propylene oxide; The system includes lime milk, chlorohydrin solution, concentrated solution, and reaction materials of concentrated solution and chlorohydrin; The concentrated liquid is obtained by concentrating the saponification residue produced by the saponification reaction. The chlorohydrin solution is the reaction solution obtained after the reaction products of propylene with chlorine and water undergo a chlorohydrin reaction.

10. The production method according to any one of claims 7-9, characterized in that, Part of the saponification residue produced by the saponification reaction is acidified to neutralize the calcium hydroxide therein.

11. The production method according to any one of claims 7-9, characterized in that, The method for producing propylene oxide further includes: the saponification residue after acidification treatment is separated into solid and liquid components and sent to industrial water treatment and waste residue treatment.

12. The production method according to claim 9, characterized in that, The saponification residue contains 0.1-0.2% calcium hydroxide and 0.2-0.5% calcium carbonate; and / or the concentrate contains 0.5-1.5% calcium hydroxide and 1-5% calcium carbonate.

13. The production method according to claim 9, characterized in that, The solid particles in the saponification residue also include one, two or more of the following: oxides, hydroxides, carbonates or hydrochloric acid insolubles of metallic or non-metallic elements.

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