CN111978273A - Continuous synthesis process of epoxy chloropropane by hydrogen peroxide method - Google Patents

Abstract

The invention proposes a continuous synthesis process of epichlorohydrin by a hydrogen peroxide method. Hydrogen peroxide, methanol, chloropropene and a catalyst are put into a reactor for epoxidation reaction. The reactor is a loop reactor, and the catalyst is pre-installed Into the loop reactor, allyl chloride and methanol in the mixing tank to form a mixture of allyl chloride and methanol is pumped into the loop reactor by metering pump A, and hydrogen peroxide is pumped into the loop reactor by metering pump B at the same time. The synthesis process of the invention has less methanol consumption, long catalyst service life, simple process device, and realizes continuous operation. In the long-term continuous operation process, relatively stable hydrogen peroxide conversion rate and high epichlorohydrin selection rate can be obtained. sex.

Description

A kind of hydrogen peroxide method epichlorohydrin continuous synthesis technology

technical field

The invention belongs to the field of catalytic synthesis, and relates to a method for synthesizing epichlorohydrin, more particularly, the invention relates to a continuous synthesis process for epichlorohydrin by a hydrogen peroxide method.

Background technique

Epichlorohydrin is an important organic chemical raw material and fine chemical product. Because its molecule contains active epoxy groups and chlorine atoms, its chemical properties are quite active, and it has become an important basic organic chemical raw material and intermediate. It is widely used in the synthesis of epoxy resin, glycerin, alcohol rubber, medicine, pesticide, surfactant, glass fiber reinforced plastic, ion exchange resin, coating and plasticizer.

At present, research at home and abroad mainly focuses on the process of preparing epichlorohydrin by direct epoxidation of chloropropene using hydrogen peroxide as the oxygen source. This process route does not produce salt-containing wastewater, only the water generated by the reaction, which has high atomic utilization and pollution. Small. CN101124044A discloses a production process of epichlorohydrin. Using titanium-silicon molecular sieve as catalyst and methanol as solvent, epichlorohydrin is directly epoxidized to prepare epichlorohydrin; It is configured into a homogeneous phase with hydrogen peroxide. At a certain temperature, it is pumped into a fixed bed for the reaction. This reaction requires the feed to be configured into a homogeneous phase, so a large amount of methanol needs to be used, and the recovery energy consumption of methanol is relatively high. CN102093313A introduces a method for preparing epichlorohydrin. Hydrogen peroxide, methanol, chloropropene and catalyst are put into a reactor for direct epoxidation reaction, and the reacted liquid-solid mixture is subjected to membrane separation to obtain a solid part and a liquid part. Part is the catalyst, and the liquid part is separated and refined to obtain epichlorohydrin. The catalyst in this process has a short usage time, and the catalyst needs to be regenerated for each reaction, the process is complicated, and the energy consumption is high.

SUMMARY OF THE INVENTION

The object of the present invention is to overcome the deficiencies in the above-mentioned epichlorohydrin synthesis process, and adopt a loop reactor to provide a kind of epichlorohydrin synthesis process with few methanol consumption, simple process device and continuous operation.

The object of the present invention is achieved through the following technical solutions: hydrogen peroxide, methanol, propylene chloride and a catalyst are put into a reactor to carry out epoxidation reaction, and it is characterized in that, the reactor is a loop reactor, and the catalyst is preloaded into a ring In the type reactor, allyl chloride and methanol form a mixture of allyl chloride and methanol in the mixing tank, which is pumped into the loop reactor by the metering pump A, and the hydrogen peroxide is pumped into the loop reactor by the metering pump B at the same time.

The catalyst is a TS-1 catalyst and is packed in one or more stages.

The loop reactor is also connected with other components, the other components include a forced circulation pump, a mixer, a settling tank or centrifugal equipment, a withdrawal valve, and a reaction liquid collection tank.

The outlet of the loop reactor is also connected to a filter, preferably a ceramic filter.

The molar ratio of allyl chloride and hydrogen peroxide is 1-4:1.

The molar ratio of methanol and hydrogen peroxide is 1-5:1.

The hydrogen peroxide concentration is 10-70%.

The reaction temperature is 0-80°C.

The residence time of the reactants in the loop reactor is 0.1-10 h.

The reaction pressure is 0-1 MPa.

The continuous synthesis process of epichlorohydrin by the hydrogen peroxide method proposed in the present invention adopts a loop reactor and has the following advantages: (1) realizing continuous operation, high safety of the reaction process, and precise control; (2) without using a large amount of methanol, reducing methanol Recycling; ③The catalyst has a longer service life and does not need to separate the catalyst; ④The process device is simple and easy to realize industrialization. By adopting the method of the invention to oxidize chloropropene, in the long-term continuous operation process, relatively stable oxidant conversion rate and high target oxidation product selectivity can be obtained. In particular, by adopting the method of the present invention, the selectivity of epoxides is high, thereby reducing the difficulty of subsequent separation and purification.

Description of drawings

The accompanying drawings are used to provide a further understanding of the present invention, and constitute a part of the specification, and together with the following specific embodiments, are used to explain the present invention, but do not constitute a limitation to the present invention.

Fig. 1 is the process flow diagram of continuous synthesis of epichlorohydrin by hydrogen peroxide method of the present invention.

Detailed ways

In order to illustrate the technical solution and technical purpose of the present invention, the following specific embodiments will further introduce the present invention.

The loop reactor of the present invention uses jacket circulating water to control temperature.

The forced circulation pump of the present invention is located inside the loop reactor to ensure that the catalyst, the chloropropene methanol mixed solution and the hydrogen peroxide are evenly mixed.

The mixer of the present invention is located between the metering pump and the inlet of the loop reactor, and is used for uniformly mixing the mixture of chloropropene methanol and hydrogen peroxide.

The sedimentation tank or centrifugal device of the present invention is a common or uncommon device for sedimentation or centrifugation, located between the mixer and the inlet of the loop reactor, connected in series or in parallel with one or more stages, preventing the reaction system Mechanical impurities or particles enter the loop reactor.

The filter of the present invention is connected with the outlet of the loop reactor to prevent the passage of catalyst solid particle residues with the smallest particle size, resulting in catalyst loss.

The loop reactor of the present invention needs to wash and activate the catalyst before use. The specific operation is as follows: after the catalyst is filled in the reactor and the reactor is installed, deionized water is pumped to fill the entire loop reactor, Turn on the circulating water bath, turn on the forced circulating pump, continue to inject deionized water into the reactor through the metering pump to wash the wetting catalyst, drain the deionized water, and continue to inject methanol into the reactor through the metering pump to wet and activate the catalyst to drain the methanol.

[Example 1]

(1) Fill the TS-1 catalyst into the reactor according to Figure 1, fill the I-III sections, and install the reactor, pump deionized water to fill the entire loop reactor, open the circulating water bath, and the water temperature is 0 ° C , turn on the forced circulation pump. Continue to inject deionized water into the system through the metering pump for 4 hours to wash the wetting catalyst and drain the deionized water; continue to inject methanol into the system through the metering pump for 4 hours to wet the activated catalyst and drain the methanol.

(2) Allyl chloride and methanol are uniformly mixed according to the molar ratio of 1:1;

(3) Turn on metering pumps A and B at the same time, feed into the mixer, control the molar ratio of chloropropene and hydrogen peroxide to 1:1, and the solubility of hydrogen peroxide to 50wt%. The residence time of the control material in the loop reactor is 2h;

(4) Measure the hydrogen peroxide and gas spectrum of the produced material every 30min until the content of epichlorohydrin in the produced oil layer and water layer reaches a stable value. Stable operation was started to realize the continuous synthesis of the reaction.

(5) continuous operation under the above-mentioned conditions, during the operation, the composition of the reaction mixture output in the detection reactor is detected, and the oxidant conversion rate, epichlorohydrin selectivity are calculated, wherein, the reaction times are 2 hours, 500 hours, 1000 and the results at 2000 hours are listed in Table 1.

[Example 2]

(1) Fill the TS-1 catalyst into the reactor according to Figure 1, fill the first stage, and install the reactor, pump deionized water to fill the entire loop reactor, open the circulating water bath, and the water temperature is 10 ° C, open Forced circulation pump. Continue to inject deionized water into the system through the metering pump for 6h to wash the wetting catalyst and drain the deionized water; continue to inject methanol into the system through the metering pump for 8h to wet the activated catalyst and drain the methanol.

(2) Allyl chloride and methanol are uniformly mixed according to a molar ratio of 2:1;

(3) Open metering pumps A and B at the same time, feed into the mixer, control the molar ratio of chloropropene and hydrogen peroxide to 1:1, and the hydrogen peroxide solubility to 10wt%. The residence time of the control material in the loop reactor is 1h;

(4) Same as Example 1.

(5) Same as Example 1.

[Example 3]

(1) Fill the TS-1 catalyst into the reactor according to Figure 1, fill the I-IV sections, and install the reactor, pump deionized water to fill the entire loop reactor, open the circulating water bath, and the water temperature is 30 ° C , turn on the forced circulation pump. Continue to inject deionized water into the system through the metering pump for 8h to wash the wetting catalyst and drain the deionized water; continue to inject methanol into the system through the metering pump for 6h to wet the activated catalyst and drain the methanol.

(2) Allyl chloride and methanol are uniformly mixed according to the molar ratio of 1:1;

(3) Turn on metering pumps A and B at the same time, feed into the mixer, control the molar ratio of chloropropene and hydrogen peroxide to 3:1, and the hydrogen peroxide solubility to 70wt%. The residence time of the control material in the loop reactor is 0.1h;

(4) Same as Example 1.

(5) Same as Example 1.

[Example 4]

(1) Fill the TS-1 catalyst into the reactor according to Figure 1, fill the I-II sections, and install the reactor, pump deionized water to fill the entire loop reactor, open the circulating water bath, and the water temperature is 80 ° C , turn on the forced circulation pump. Continue to inject deionized water into the system through the metering pump for 10h to wash the wetting catalyst and drain the deionized water; continue to inject methanol into the system through the metering pump for 24h to wet the activated catalyst and drain the methanol.

(2) Allyl chloride and methanol are uniformly mixed according to a molar ratio of 5:1;

(3) Open metering pumps A and B at the same time, feed into the mixer, control the molar ratio of chloropropene and hydrogen peroxide to 2:1, and the hydrogen peroxide solubility of 70wt%. The residence time of the control material in the loop reactor is 10h;

(4) Same as Example 1.

(5) Same as Example 1.

[Example 5]

(1) Fill the TS-1 catalyst into the reactor according to Figure 1, fill the I-IV sections, and install the reactor, pump deionized water to fill the entire loop reactor, open the circulating water bath, and the water temperature is 20 ° C , turn on the forced circulation pump. Continue to inject deionized water into the system through the metering pump for 10h to wash the wetting catalyst and drain the deionized water; continue to inject methanol into the system through the metering pump for 12h to wet the activated catalyst and drain the methanol.

(2) Allyl chloride and methanol are uniformly mixed according to a molar ratio of 4:3;

(3) simultaneously open metering pump A, B, feed to mixer, control chloropropene and hydrogen peroxide mol ratio 4:1,

Hydrogen peroxide solubility 40wt%. The residence time of the control material in the loop reactor is 3h;

(4) Same as Example 1.

(5) Same as Example 1.

[Example 6]

(1) Fill the TS-1 catalyst into the reactor according to Figure 1, fill the I-IV sections, and install the reactor, pump deionized water to fill the entire loop reactor, open the circulating water bath, and the water temperature is 10 ° C , turn on the forced circulation pump. Continue to inject deionized water into the system through the metering pump for 12h to wash the wetting catalyst and drain the deionized water; continue to inject methanol into the system through the metering pump for 16h to wet the activated catalyst and drain the methanol.

(2) Allyl chloride and methanol are uniformly mixed according to a molar ratio of 3:5;

(3) simultaneously open metering pump A, B, feed to mixer, control chloropropene and hydrogen peroxide mol ratio 3:1,

Hydrogen peroxide solubility 60wt%. The residence time of the control material in the loop reactor is 1h;

(4) Same as Example 1.

(5) Same as Example 1.

Table 1 Example 1-6 continuous running result data

[Comparative Example 1]

(1) Add allyl chloride, methanol, hydrogen peroxide and catalyst in the same proportions as in Example 5, heat up to 42°C, and react for 2h.

(2) reaction finishes, detects the hydrogen peroxide residue and epichlorohydrin content of reaction solution, calculates the hydrogen peroxide conversion rate and the yield of epichlorohydrin. The catalyst was filtered and used for the next batch of epoxidation.

The results are listed in Table 2.

Table 2 Comparative Example Catalyst Application Result Data

The content of the present invention is not limited to the content of the embodiments of the present invention.

The structure and implementation of the present invention are described herein by using specific examples, and the descriptions of the above embodiments are only used to help understand the core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can also be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims (10)

1. A continuous synthesis process of epoxy chloropropane by hydrogen peroxide is characterized in that hydrogen peroxide, methanol, chloropropene and a catalyst are put into a reactor for epoxidation, the reactor is a ring reactor, the catalyst is pre-loaded into the ring reactor, chloropropene and methanol form a chloropropene-methanol mixed solution in a mixing tank, the chloropropene-methanol mixed solution is pumped into the ring reactor by a metering pump A, and hydrogen peroxide is pumped into the ring reactor by a metering pump B.

2. The continuous synthesis process of epichlorohydrin by hydrogen peroxide method according to claim 1, wherein the catalyst is a TS-1 catalyst and is packed in 1 or more stages.

3. The continuous synthesis process of epichlorohydrin by hydrogen peroxide method according to claim 1, wherein the loop reactor is further connected with other components, and the other components comprise a forced circulation pump, a mixer, a settling tank or a centrifugal device, a production valve and a reaction liquid collecting tank.

4. The continuous synthesis process of epichlorohydrin by hydrogen peroxide method according to claim 3, wherein the outlet of the loop reactor is further connected with a filter, preferably a ceramic filter.

5. The continuous synthesis process of epoxy chloropropane by using a hydrogen peroxide method according to claim 1, characterized in that the molar ratio of chloropropene to hydrogen peroxide is 1-4: 1.

6. The continuous synthesis process of epichlorohydrin by a hydrogen peroxide method according to claim 1, wherein the molar ratio of methanol to hydrogen peroxide is 1-5: 1.

7. The continuous synthesis process of epichlorohydrin by using hydrogen peroxide as claimed in claim 1, wherein the concentration of hydrogen peroxide is 10-70%.

8. The process for the continuous synthesis of epichlorohydrin by hydrogen peroxide method according to claim 1, wherein the reaction temperature is 0-80 ℃.

9. The continuous synthesis process of epichlorohydrin by hydrogen peroxide method according to claim 1, wherein the residence time of the reactants in the loop reactor is 0.1-10 h.

10. The process for continuously synthesizing epichlorohydrin by a hydrogen peroxide method according to claim 1, wherein the reaction pressure is 0-1 MPa.

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