CN114315518A - Chlorohydrination reaction device and application thereof - Google Patents

Abstract

The invention discloses a chlorohydrin reaction device and its application. The reaction device includes a hypochlorous acid reaction zone and a chlorohydrin reaction zone, both of which include a gas phase zone, and each gas phase zone is independent of each other for accommodating unreacted reaction gas in each reaction zone; Independent" means that the gases in the two gas phase regions exist independently of each other and are not in contact with each other. By setting up two gas-phase spaces independent of each other, the side reaction caused by the direct gas-phase contact of chlorine and olefins is avoided, the generation of low-value chlorinated by-products is greatly reduced, and the unit consumption of chlorohydrins is reduced.

Description

A kind of chlorohydrin reaction device and its application

technical field

The invention belongs to the field of chlorohydrin reaction, in particular to a chlorohydrin reaction device and application thereof.

Background technique

Chlorohydrin reaction is one of the important industrial methods of alkylene oxide. For example, chlorine gas and propylene are contacted in water, hypochlorous acid generated by chlorine gas and water reacts with propylene to form chloropropanol, and chloropropanol is contacted with calcium hydroxide to produce propylene oxide. (PO). The method for preparing alkylene oxide by chlorohydrin reaction has the advantages of short process flow, mature technology, safe production and small capital construction investment.

During the chlorohydrin reaction of propylene, there are main reactions and side reactions at the same time, resulting in by-products such as chloropropanol and dichloropropane.

Main reaction:

side effects:

The reaction of propylene with hypochlorous acid (eq. (2)) is rapid, as is the rapid reaction of propylene with free chlorine (eq. (3)) to produce a dichloropropane by-product. The industrially used chlorohydrin reactors include single-column chlorohydrin reactors, tubular chlorohydrin reactors, three-column series chlorohydrin reactors, and tube-to-column combined chlorohydrin reactors, all of which have the same shortcoming. : Undissolved chlorine and unreacted olefins diffuse into the same gas-phase space to quickly react to generate by-products, such as the chlorohydrin method to prepare propylene oxide device, and per ton of propylene oxide by-produced low-value solvent dichloropropane 150-180kg.

SUMMARY OF THE INVENTION

In order to improve the deficiencies of the prior art, the present invention provides a chlorohydrin reaction device. The reaction device includes a hypochlorous acid reaction zone and a chlorohydrin reaction zone. Both reaction zones include a gas phase zone. To accommodate unreacted reaction gas in each reaction zone.

Wherein, the "independent of each other" means that the gases in the two gas phase regions exist independently of each other and do not contact each other.

According to an embodiment of the present invention, both the hypochlorous acid reaction zone and the chlorohydrin reaction zone also include a solution zone, the solution zone of the hypochlorous acid reaction zone is denoted as the first solution zone, and the solution zone of the chlorohydrin reaction zone is denoted as the first solution zone is the second solution area.

According to an embodiment of the present invention, in each reaction zone, the gas phase zone is located above the solution zone.

According to an embodiment of the present invention, the first solution zone and the second solution zone are communicated or not communicated, preferably communicated. Those skilled in the art can understand that there is no particular limitation on the manner of realizing the communication, for example, the hypochlorous acid reaction area and the chlorohydrin reaction area are connected through a pipeline to realize the communication of the solution area.

Exemplarily, a first communication line may be provided at the bottom of the hypochlorous acid reaction zone and the bottom of the chlorohydrin reaction zone, so as to realize the communication between the first solution zone and the second solution zone.

Preferably, a second communication line may also be provided in the middle and upper part of the hypochlorous acid reaction zone and the middle and upper part of the chlorohydrin reaction zone, so as to realize the circulation of the liquid in the first solution zone and the second solution zone.

Preferably, a liquid delivery device may be provided on any of the communication lines, for example, a liquid delivery device may be provided on the second communication line. Preferably, the liquid delivery device may be a pump.

According to an embodiment of the present invention, the gas phase zone of the hypochlorous acid reaction zone is denoted as the first gas phase zone, the gas phase zone of the chlorohydrin reaction zone is denoted as the second gas phase zone, and the first gas phase zone is used to accommodate unreacted chlorine gas, The second gas phase zone is used to contain unreacted olefins.

According to an embodiment of the present invention, the first gas phase region is connected with the first solution region, and the second gas phase region is connected with the second solution region, and the connection point is the liquid level of the solution.

According to an embodiment of the present invention, the reaction device includes a line for introducing chlorine gas, and the gas outlet of the line for introducing chlorine gas is disposed in the first solution zone.

According to an embodiment of the present invention, the reaction device further includes a first gas phase line, the first gas phase line is connected to the first gas phase zone for discharging unreacted chlorine gas.

According to an embodiment of the present invention, the first gas phase pipeline can be connected with a pipeline for introducing chlorine gas, and the chlorine gas produced from the first gas phase zone can be reused as a raw material gas. Preferably, a pressurizing device is provided on the connecting line between the first gas phase line and the chlorine gas inlet line. For example, the boosting device may be a compressor or a fan.

According to an embodiment of the present invention, the reaction device further comprises at least one pipeline for introducing olefins, and the gas outlet of the pipeline for introducing olefins is arranged at least in the second solution zone, preferably in the middle and lower part of the second solution zone . Further, when there are two pipelines for feeding the olefin, the gas outlet of one olefin feeding pipeline is set in the second solution zone (preferably set in the middle and lower part of the second solution zone), and the other olefin feeding The pipeline is arranged in the middle and lower part of the first solution zone (preferably arranged on the opposite side of the pipeline for chlorine gas introduction).

According to an embodiment of the present invention, the olefin may be selected from ethylene, propylene, chloropropene or butene, and the like.

According to an embodiment of the present invention, the reaction apparatus further includes a second gas phase line connected to the second gas phase zone for discharging unreacted olefins.

According to an embodiment of the present invention, the second gas phase line is connected to the olefin feed line communicated with the second solution zone, and the gas phase produced from the second gas phase zone is reused as a raw material gas. Preferably, a pressurizing device is provided on the connecting line between the second gas phase line and the olefin inlet line communicating with the second solution zone. For example, the boosting device may be a compressor or a fan.

According to an embodiment of the present invention, the reaction device may further include a process water line for supplementing the water required for the reaction into each reaction zone. Preferably, the process water line is connected to each gas phase zone.

According to an embodiment of the present invention, the hypochlorous acid reaction zone and the chlorohydrin reaction zone further comprise a thermal insulation layer. Preferably, the thermal insulation layer covers at least the solution area.

According to an embodiment of the present invention, the reaction device may further comprise a reaction liquid outflow line, and the reaction liquid outflow line is connected with the second solution zone, preferably located at the upper part of the second solution zone.

According to an embodiment of the present invention, the reaction device further comprises a stirrer, and the stirrer is used for stirring the materials in the solution zone in each reaction zone.

The present invention also provides the application of the above chlorohydrin reaction device in the preparation of chlorohydrin and/or the preparation of propylene oxide.

The present invention also provides a method for preparing chlorohydrins, comprising the following steps: reacting chlorine gas and olefins in the above chlorohydrin reaction device to prepare chlorohydrin.

According to an embodiment of the present invention, chlorine gas is introduced into the first solution zone, the chlorine and water are contacted and then dissolved and reacted to generate hypochlorous acid and HCl, and the undissolved chlorine gas enters the first gas phase zone; The olefin, the olefin reacts in the second solution zone with the aqueous hypochlorous acid solution from the first solution zone to obtain chlorohydrins, and the unreacted olefin enters the second gas phase zone.

According to an embodiment of the present invention, the olefin is ethylene, propylene, propylene chloride, butene, or the like.

According to an embodiment of the present invention, the ratio of the total molar amount of olefins to the molar amount of chlorine gas is (1.01-1.3):1, eg (1.05-1.16):1.

According to an embodiment of the present invention, the ratio of the molar amount of the olefin that is passed into the olefin feed line arranged in the middle and lower part of the first solution zone to the molar amount of the chlorine gas passed into the chlorine gas feed line is (0-0.99):1.

According to an embodiment of the present invention, the reaction temperature is 10-100°C, preferably 30-80°C, more preferably 40-60°C.

Beneficial effects of the present invention:

In the chlorohydrin reaction device provided by the invention, chlorine gas is introduced into the middle and lower part of the first solution zone, and the chlorine gas contacts with water and then dissolves and reacts to generate hypochlorous acid and HCl, and the undissolved chlorine gas enters the first gas phase zone; the middle and lower part of the second solution zone The olefin is introduced, the olefin reacts with the aqueous hypochlorous acid solution from the first solution zone in the second solution zone, and the unreacted olefin enters the second gas phase zone. Undissolved chlorine and unreacted olefins enter into different gas phase zones respectively, avoiding direct encounter and rapid reaction to generate chlorinated by-products. By setting two independent gas phase zones, the device reduces or even avoids the contact reaction of undissolved chlorine gas and olefin in the gas phase space, and effectively reduces the generation of by-products.

Description of drawings

1 is a schematic structural diagram of the chlorohydrin reaction device provided in Example 1.

2 is a schematic structural diagram of a chloropropanol preparation device provided in Example 2 with a double glass round bottom flask as a reaction zone.

3 is a schematic diagram of the structure of the device used in the comparative example to prepare chloropropanol with a single round bottom glass flask as the reaction zone.

V11, the first gas phase zone, V12, the first solution zone, V21, the second gas phase zone, V22, the second solution zone, 1, the chlorine gas feeding pipeline, 2, the olefin feeding pipeline, 3, the first gas phase pipeline , 4, the second gas phase pipeline, 5, the first connecting pipeline, 6, the second connecting pipeline, 7, the process water pipeline, 8, the chlorohydrin product outflow line, 9, the delivery pump, 10, the first solution zone agitator, 11. The second solution zone stirrer.

Detailed ways

The technical solutions of the present invention will be described in further detail below with reference to specific embodiments. It should be understood that the following examples are only for illustrating and explaining the present invention, and should not be construed as limiting the protection scope of the present invention. All technologies implemented based on the above content of the present invention are covered within the intended protection scope of the present invention.

Unless otherwise stated, the starting materials and reagents used in the following examples are commercially available or can be prepared by known methods.

The product analysis conditions of the following examples and comparative examples are as follows:

Analytical instrument: Agilent GC7820; chromatographic column: 30m×530μm×0.25μm DB-FFAP; detector: FID; inlet temperature: 225℃, detector temperature: 240℃, temperature program: 40℃ for 5min, 30℃/ min to 230°C, hold for 5min; H ₂ : 0.1Mpa, AIR: 0.1Mpa, N ₂ : 0.075Mpa, makeup: 0.1Mpa.

Example 1

Chlorohydrin reaction device as shown in Figure 1, comprises: hypochlorous acid reaction zone and chlorohydrin reaction zone, chlorine gas feeds with pipeline 1, olefin feeds with pipeline 2, first gas phase pipeline 3, second gas phase pipeline 4, Process water line 7 and chlorohydrin product effluent line 8. The hypochlorous acid reaction zone includes a first gas phase zone V11 and a first solution zone V12, and the chlorohydrin reaction zone includes a second gas phase zone V21 and a second solution zone V22, the first gas phase zone V11 and the second gas phase zone V21 are independent of each other, each The gas phase zone in the reaction zone is located above the solution zone.

The chlorine gas is introduced into the middle and lower part of the first solution zone V12 with the pipeline 1, and the olefin is introduced into the middle and lower part of the second solution zone V22 with the pipeline 2, and the chlorine gas of the first solution zone is introduced into the opposite side of the pipeline 1. The bottom of the first solution zone V12 and the bottom of the second solution zone V22 are connected by the first communication line 5, the middle and upper part of the first solution zone V12 and the middle and upper part of the second solution zone V22 are connected by the second communication line 6, the first The materials in the communication line and the second communication line flow in opposite directions, and conveying equipment such as a pump (not shown in the figure) is provided on either line.

The upper part of the second solution zone V22 is connected to the chlorohydrin product outflow line 8, and the chlorohydrin reaction product is produced. The first gas phase zone V11 is connected with the first solution zone V12, the connection surface is the liquid phase interface, the top of the first gas phase zone is connected with the first gas phase pipeline 3, and the upper part of the first gas phase zone is connected with the process water pipeline 7. The second gas phase space V21 is connected with the second solution region V22, the connection surface is the liquid phase interface, the top of the second gas phase region is connected with the second gas phase pipeline 4, and the upper part of the second gas phase region is connected with the process water pipeline 7.

In one embodiment, the first gas phase pipeline is connected with a pipeline for introducing chlorine gas, a pressurizing device is arranged on the connecting pipeline, and the gas phase extracted from the first gas phase zone is reused as raw material gas. The second gas phase pipeline is connected with the pipeline for olefin feeding, and a pressurizing device is arranged on the connecting pipeline, and the gas phase extracted from the second gas phase zone is reused as the raw material gas.

Example 2

Chloropropanol is prepared by the chlorohydrin reaction of propylene:

As shown in Figure 2, the reaction device includes a hypochlorous acid reaction area and a chlorohydrin reaction area, and the two reaction areas are two 500ml four-necked round-bottom glass flasks, and the bottom of the flask passes through the first communication line 5 (in the present embodiment, glass tube) connected, the total volume of the reaction solution was 800ml, and hot water was introduced into the jacket to control the reaction temperature at 50°C. The reaction flask was equipped with mechanical stirrers: a first solution zone stirrer 10 and a second solution zone stirrer 11, with a stirring speed of 100 rpm. A metering pump 9 is provided on the second communication line 6, and the flow rate of the delivery pump 9 is 26.5 L/h.

Chlorine is passed into the first solution zone V12 at a speed of 52ml/min (2.3mmol/min) through chlorine through pipeline 1, and propylene is passed into the second solution at a speed of 62ml/min (2.7mmol/h) through olefin through pipeline 2. Solution Zone V22. The delivery pump 9 draws out the solution from the second solution area, and sends it into the first solution area V12. The second solution region V22 flows into the first solution region V12.

The undissolved chlorine gas comes out from the first gas phase pipeline 3, is absorbed by the lye, and is measured and analyzed. Unreacted propylene and the like are discharged from the second gas phase line 4, absorbed in -20°C ethyl acetate, and analyzed by measurement.

After aeration for 190 min, the mass fraction of chloropropanol in the reaction solution reached about 3.5 wt%.

Analysis of chloropropanol and impurity content in the reaction material, analysis of chlorine and impurity content in the first gas phase line 3 outlet, analysis of propylene and impurity content (main impurity is dichloropropane (DCP)) in the second gas phase line 4 outlet. The comprehensive analysis results showed that the content of chloropropanol in the reaction solution was 3.52wt%, the content of DCP was 0.022wt%, the content of PCE was 0.010wt%, and the content of chloroacetone was 0.010wt%.

Examples 3-6

The process is the same as that of Example 2, and the ventilation time is shown in Table 1. The analysis results of the reaction materials are shown in Table 1. Control the gas introduction time.

Table 1

Note: impurities/chloropropanol=(the mass percentage of dichloropropane in the reaction solution+the mass percentage of dichlorodiisopropyl ether+the mass percentage of chloroacetone)/the mass of chloropropanol in the reaction solution percent content.

Comparative Examples 1-3

The reaction device shown in Figure 3, the reaction device is a 1000ml four-necked round bottom glass flask, the total volume of the reaction solution is 800ml, and hot water is introduced to control the reaction temperature of 50°C. The reaction flask was equipped with mechanical stirring at 100 rpm.

Chlorine gas was passed under the reaction liquid surface at a rate of 52 ml/min (2.3 mmol/min) through a pipeline, and propylene was passed into the reaction liquid surface at a rate of 62 ml/min (2.7 mmol/h) through a pipeline.

The gas phase is removed from the gas phase space of the reaction flask and absorbed in two stages of lye and ethyl acetate.

Analyze the content of chloropropanol and impurities in the reaction material, analyze the content of chlorine, propylene and impurities in the gas phase removed from the reaction bottle (the main impurity is dichloropropane (DCP)). The analysis results are shown in Table 2.

Table 2

Note: impurities/chloropropanol=(the mass percentage of dichloropropane in the reaction solution+the mass percentage of dichlorodiisopropyl ether+the mass percentage of chloroacetone)/the mass of chloropropanol in the reaction solution percent content.

It can be seen from the comparative example that using the reaction device of the present invention, by setting two independent gas-phase spaces, the contact reaction of undissolved chlorine and olefins in the gas-phase space is reduced or even avoided, and the reaction by-products are reduced by nearly 7 times.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. a chlorohydrin reaction unit, it is characterized in that, described reaction unit comprises hypochlorous acid reaction zone and chlorohydrin reaction zone, two reaction zones both comprise gas phase zone, each gas phase zone is independent of each other, is used for accommodating each reaction zone unreacted reactive gases in; Wherein, the "independent of each other" means that the gases in the two gas phase regions exist independently of each other and do not contact each other. 2. chlorohydrin reaction device according to claim 1, is characterized in that, described hypochlorous acid reaction zone and chlorohydrin reaction zone also comprise solution zone, and the solution zone of hypochlorous acid reaction zone is marked as the first solution zone, the solution zone of the chlorohydrin reaction zone is recorded as the second solution zone. Preferably, the gas phase zone is located above the solution zone in each reaction zone. 3. The chlorohydrin reaction device according to claim 1 or 2, characterized in that, the first solution area and the second solution area are connected or not connected, preferably connected. For example, the hypochlorous acid reaction zone and the chlorohydrin reaction zone are connected by a pipeline to realize the communication of the solution zone. Preferably, a first communication line is arranged at the bottom of the hypochlorous acid reaction zone and the bottom of the chlorohydrin reaction zone, so as to realize the communication between the first solution zone and the second solution zone. Preferably, a second communication line is arranged in the middle and upper part of the hypochlorous acid reaction zone and the middle and upper part of the chlorohydrin reaction zone, so as to realize the circulation of the liquid in the first solution zone and the second solution zone. Preferably, a liquid delivery device is provided on any of the above-mentioned communication lines. Preferably, the liquid delivery device is a pump. 4. The chlorohydrin reaction device according to any one of claims 1-3, wherein the gas phase zone in the hypochlorous acid reaction zone is denoted as the first gas phase zone, and the gas phase zone in the chlorohydrin reaction zone is denoted as the first gas phase zone. The zone is designated as the second gas phase zone, the first gas phase zone is used for containing unreacted chlorine gas, and the second gas phase zone is used for containing unreacted olefin. Preferably, the first gas phase region is connected with the first solution region, and the second gas phase region is connected with the second solution region, and the connection point is the liquid level of the solution. 5. The chlorohydrin reaction device according to any one of claims 1-4, wherein the reaction device comprises a chlorine gas feeding pipeline, and the gas outlet of the chlorine gas feeding pipeline is arranged in the first solution zone Inside. Preferably, the reaction device further comprises a first gas phase line, the first gas phase line is connected to the first gas phase zone for discharging unreacted chlorine gas. Preferably, the first gas phase pipeline is connected with a chlorine gas introduction pipeline, and the chlorine gas extracted from the first gas phase zone is reused as a raw material gas. Preferably, a pressurizing device is provided on the connecting line between the first gas phase line and the chlorine gas inlet line. For example, the booster device is a compressor or a fan. 6. The chlorohydrin reaction device according to any one of claims 1-5, characterized in that, the reaction device further comprises at least one olefin feeding pipeline, and the gas outlet of the olefin feeding pipeline is arranged at least at The second solution zone is preferably arranged in the middle and lower part of the second solution zone. Preferably, when there are two olefin feeding pipelines, the gas outlet of one olefin feeding pipeline is set in the second solution zone (preferably set in the middle and lower part of the second solution zone), and the other olefin feeding pipeline The pipeline is arranged in the middle and lower part of the first solution zone (preferably arranged on the opposite side of the pipeline for chlorine gas introduction). Preferably, the reaction device further comprises a second gas phase line, the second gas phase line is connected to the second gas phase zone for discharging unreacted olefins. Preferably, the second gas phase line is connected to the olefin feed line communicating with the second solution zone, and the gas phase produced from the second gas phase zone is reused as the raw material gas. Preferably, a pressurizing device is provided on the connecting line between the second gas phase line and the olefin inlet line communicating with the second solution zone. For example, the booster device is a compressor or a fan. 7. The chlorohydrin reaction device according to any one of claims 1-6, characterized in that, the reaction device further comprises a process water pipeline for supplementing the water required for the reaction into each reaction zone. Preferably, the process water line is connected to each gas phase zone. Preferably, the hypochlorous acid reaction zone and the chlorohydrin reaction zone further comprise a thermal insulation layer. Preferably, the thermal insulation layer covers at least the solution area. Preferably, the reaction device further comprises a reaction liquid outflow line, and the reaction liquid outflow line is connected to the second solution zone, preferably located at the upper part of the second solution zone. Preferably, the reaction device further comprises a stirrer, and the stirrer is used for stirring the materials in the solution zone of each reaction zone. 8. The application of the chlorohydrin reaction device described in any one of claims 1-7 in the preparation of chlorohydrin and/or the preparation of propylene oxide. 9. A preparation method of chlorohydrin, characterized in that, the preparation method comprises the steps of: reacting chlorine gas and olefin in the chlorohydrin reaction device according to any one of claims 1-7 to prepare chlorohydrin. 10. preparation method according to claim 9, is characterized in that, described preparation method comprises the steps: feed chlorine gas into the first solution zone, after chlorine gas contacts with water, dissolving reaction, generates hypochlorous acid and HCl, does not have. Dissolved chlorine gas enters the first gas phase zone; feeds olefin into the second solution zone, the olefin reacts with the hypochlorous acid aqueous solution from the first solution zone in the second solution zone to obtain chlorohydrins, and the unreacted olefin enters the second gas phase zone . Preferably, the olefin is ethylene, propylene, allyl chloride or butene.

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