CN111440047A

CN111440047A - Preparation method of 1,1,1,3, 3-pentachloropropane

Info

Publication number: CN111440047A
Application number: CN202010337294.2A
Authority: CN
Inventors: 陶文平; 孙运林; 张驰; 王顺利; 董亮; 吴发明; 马凯; 刘向超; 朱成明
Original assignee: Changzhou Xindong Chemical Industry Development Co ltd
Current assignee: Changzhou Xindong Chemical Industry Development Co ltd
Priority date: 2020-04-26
Filing date: 2020-04-26
Publication date: 2020-07-24
Anticipated expiration: 2040-04-26
Also published as: CN111440047B

Abstract

The invention discloses a preparation method of 1,1,1,3, 3-pentachloropropane, which comprises the steps of mixing carbon tetrachloride and an auxiliary agent, preheating, forcibly circulating for a period of time, forcibly reacting with chloroethylene in a reinforced reactor to obtain a 1,1,1,3, 3-pentachloropropane crude product, and finally carrying out reduced pressure rectification separation to obtain the 1,1,1,3, 3-pentachloropropane. The preparation method of the 1,1,1,3, 3-pentachloropropane provided by the invention has the advantages of simple process, low energy consumption, easily controlled reaction process, recyclable vinyl chloride, carbon tetrachloride, auxiliary agents and residual liquid in a tower kettle, high material utilization rate, less waste generation, high purity of prepared target products, and high efficiency and environmental protection by using a catalyst without ammonia nitrogen and phosphorus.

Description

Preparation method of 1,1,1,3, 3-pentachloropropane

Technical Field

The invention relates to 1,1,1,3, 3-pentachloropropane, in particular to a method for preparing 1,1,1,3, 3-pentachloropropane by using carbon tetrachloride and chloroethylene as raw materials.

Background

The 1,1,1,3, 3-pentafluoropropane (HFC-245 fa) can be used for foaming rigid polyurethane and polyisocyanurate foam insulating plastics, and can also be used as a foaming agent which does not destroy an ozone layer, a refrigerant, a cleaning agent, a heat transfer medium, an aerosol propellant and the like instead of CFC-11, CFC-12 and HCFC-141 b. 1,1,1,3, 3-pentachloropropane (HCC-240 fa) is an important intermediate for preparing 1,1,1,3, 3-pentafluoropropane (HFC-245 fa), HFC-245fa obtained by preparing HCC-240fa is subjected to dehydrofluorination reaction to prepare 1,3,3, 3-tetrafluoropropene (HFO-1234 ze) with low global warming potential (GWP value), and the HFO-1234ze is considered to be a good substitute for HFC-134a and the like used for foaming agents, refrigerants and aerosol propellants; 1-chloro-3, 3, 3-trifluoropropene (HFO-1233 zd) with lower GWP value can be prepared by taking HCC-240fa and hydrofluoric acid (HF) as raw materials through fluorination reaction, and the HFO-1233zd can be applied to the fields of foaming, refrigeration, cleaning and the like; in addition, HFO-1234ze and HFO-1233zd may also be used as fluoropolymer monomers.

The preparation method of 1,1,1,3, 3-pentachloropropane is more, and according to the difference of raw materials, the preparation route of 1,1,1,3, 3-pentachloropropane mainly comprises the following three routes: (1) taking l, 1-dichloroethylene and carbon tetrachloride as raw materials, and carrying out addition, elimination and hydrogenation reduction reaction to obtain 1,1,1,3, 3-pentachloropropane; (2) ethylene and carbon tetrachloride are used as raw materials, and 1,1,1,3, 3-pentachloropropane is prepared through addition and photochlorination; (3) taking chloroethylene and carbon tetrachloride as raw materials, and carrying out addition reaction to generate 1,1,1,3, 3-pentachloropropane; in the three synthesis routes, the (1) th synthesis route and the (2) th synthesis route are both multi-step synthesis methods, and because the reaction steps are multiple, the raw material investment, the production equipment investment, the personnel investment and the environmental protection treatment investment in the production process can be increased, so that the production operation cost is increased, and the (3) th synthesis route is the most reaction route adopted at present, so that the raw materials are easily obtained, and the synthesis process is relatively simple.

The method mainly comprises a copper-amine catalytic telomerization synthesis process and an iron-phosphate catalytic telomerization synthesis process by taking vinyl chloride and carbon tetrachloride as raw materials according to different catalysts. For example, CN103274893A discloses a method for preparing 1,1,1,3, 3-pentachloropropane, which comprises adding iron, ferric chloride, and triethyl phosphate into a carbon tetrachloride tank to prepare a catalyst, wherein a phosphorus-containing catalyst is used for aftertreatment and causes great environmental pollution, and in addition, the used iron powder is easy to agglomerate on the surface of a reactor after reaction, and is difficult to clean, and the fine iron powder is dispersed in organic high boiling water, which results in high consumption and difficult separation and recycling; CN104230648A discloses a preparation process of 1,1,1,3, 3-pentachloropropane, the copper-amine catalyst has strong corrosivity, the product has high viscosity, and the continuous operation is not facilitated; CN104230649A discloses a preparation method of pentachloropropane, in which the catalyst is filtered, washed with water, dried and recovered, and the addition of water actually causes the catalyst to be damaged, and the recovery operation becomes complicated.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the preparation method of the 1,1,1,3, 3-pentachloropropane, which is green and environment-friendly, has simple process and is easy to industrialize. In order to achieve the technical purpose, the technical scheme adopted by the invention is as follows: a preparation method of 1,1,1,3, 3-pentachloropropane mainly comprises the following steps:

(1) uniformly mixing an auxiliary agent and carbon tetrachloride according to a molar ratio of 0.005-0.05: 1, preheating to 60-75 ℃, adding the mixture into a pipeline strengthening reactor, and carrying out cyclic reaction for 3-6 h;

(2) introducing chloroethylene into a reinforced reactor for forced circulation reaction at the reaction temperature of 65-140 ℃ and the reaction pressure of 0.5-2.5 MPa in a feeding amount of chloroethylene and carbon tetrachloride in a molar ratio of 1: 1.5-3;

(3) adding the reaction liquid after the forced circulation reaction in the step (2) into a first rectifying tower for rectification, wherein the temperature of a rectifying tower kettle is 60-90 ℃, the rectification pressure is 1.5-10 kPa, carbon tetrachloride and an auxiliary agent are obtained at the tower top of the first rectifying tower, and crude 1,1,1,3, 3-pentachloropropane is obtained at the tower kettle;

(4) adding the crude 1,1,1,3, 3-pentachloropropane into a second rectifying tower for high vacuum rectification, wherein the temperature of the kettle of the rectifying tower is 70-100 ℃, the rectifying pressure is 200-900 Pa, obtaining the 1,1,1,3, 3-pentachloropropane at the top of the second rectifying tower, and recovering residual liquid in the kettle of the rectifying tower.

Further, the auxiliary agent is ethanol or 12-crown-4, preferably ethanol, and the molar ratio of the auxiliary agent to carbon tetrachloride is 0.005-0.05: 1.

Further, in the step (2), the vinyl chloride is fully mixed with the liquid material in the Venturi mixer and then is sent into the strengthening reactor.

Further, sampling and analyzing every 0.5h in the reaction process of the step (2), and stopping the reaction when the carbon tetrachloride conversion rate reaches 34-66%.

Furthermore, the reinforced reactors are pipeline reactors with external pumping circulation, iron theta ring packing or iron saddle ring packing or iron pall ring packing, preferably iron theta ring packing, are filled in the reinforced reactors, and the packing is stacked into a porous iron packing bed structure.

Further, vinyl chloride, carbon tetrachloride and an auxiliary agent fraction obtained from the top of the first rectifying tower are recycled to the step (1) for reuse.

Further, 5-25% of the residue in the second rectifying tower is used as a waste liquid discharge system, and 75-95% of the residue is recycled to the step (2).

The invention utilizes hydrogen chloride generated by micro thermal decomposition of materials to generate a ferrous chloride catalyst required by telomerization reaction by continuously scouring iron filler with a porous structure in a circulating reactor; the reinforced reactor is adopted, so that the mixing and intermiscibility of gas and liquid phases are enhanced; the solubility of the ferric salt catalyst in a reaction system is further increased by adding 12-crown ether-4 or an ethanol auxiliary agent, so that the 1,1,1,3, 3-pentachloropropane is prepared in an intensified reactor.

The invention has the following beneficial effects:

1) controlling the excess of carbon tetrachloride, fully converting chloroethylene, and diluting the product to reduce the decomposition of the product 1,1,1,3, 3-pentachloropropane to obtain a product with the purity not lower than 99.7 percent, wherein the conversion rate of the carbon tetrachloride is low (34-66 percent);

2) chloroethylene, carbon tetrachloride, an auxiliary agent and the residue of the second rectifying tower can be recycled, the generation of waste is less, and the residue of the rectifying tower containing a certain amount of ferrous chloride catalyst can be used mechanically, so that the telomerization reaction activity in the enhanced reactor can be further improved.

3) The porous iron packed bed stacked by the iron theta ring packing or the iron saddle ring packing or the iron pall ring packing is adopted to replace the traditional iron powder, so that the problem that the iron powder is difficult to recycle after reaction is solved, and the iron which is greatly excessive can reduce a small amount of oxidized ferrous chloride again while slowly releasing the ferrous chloride catalyst, thereby avoiding the high boiling caused by the catalytic decomposition of the material by the ferrous chloride; the porous iron packed bed with the tightly packed fillers can promote the dispersion of the additives, increase the contact area of gas phase and liquid phase, ensure more sufficient reaction, avoid the adhesion and agglomeration of iron mud on the surface of the reactor after the reaction due to the scouring effect and prolong the service time of the reactor;

4) ethanol or phenetole is used as an auxiliary agent to replace the traditional phosphate ester substances to be used as a solubilizer of the ferrous chloride, so that the solubility of the washed ferrous chloride catalyst in materials can be increased, the telomerization reaction rate is improved, and the problem of pollution of three wastes containing nitrogen and phosphorus in the traditional process is solved;

5) the gas-liquid mixer with the Venturi mixer is used, so that the chloroethylene and the carbon tetrachloride can be fully mixed, the dispersity of the chloroethylene in the carbon tetrachloride is greatly improved, the solubility of the chloroethylene in the carbon tetrachloride is improved, and the reaction efficiency is improved; in addition, the telomerization reaction of vinyl chloride and carbon tetrachloride is a strong exothermic reaction, and the material decomposition caused by overhigh local reaction temperature is reduced while the dispersibility of reaction materials is improved by using the reinforced reactor.

Drawings

FIG. 1 is a schematic diagram of the process flow for producing 1,1,1,3, 3-pentachloropropane according to the present invention.

Wherein the reference numerals are: the system comprises a preheating kettle 1, a strengthening reactor 2, a circulating pump 3, a gas-liquid mixer 4, a first rectifying tower 5 and a second rectifying tower 6.

Detailed Description

The present invention is further illustrated by the following examples, but the present invention is not limited to these examples.

Example 1

The strengthening reactor 2 is a pipeline reactor with the internal diameter of 50mm and the length of 32.0m and with an in-vitro pumping circulation, and a porous iron packed bed with iron theta ring packing accumulated is filled inside the pipeline reactor; the preparation process flow of the 1,1,1,3, 3-pentachloropropane is as follows:

1) mixing an auxiliary agent (ethanol) and carbon tetrachloride according to a molar ratio of 0.05:1, preheating to 74.9 ℃ in a preheating kettle 1, adding a mixture into a strengthening reactor 2, continuously pumping materials at the upper part of the reactor by using a circulating pump 3, and pumping the materials into the bottom of the reactor to forcibly and uniformly mix the mixture and circulate for 6 hours;

2) heating the intensified reactor 2 to 138.9 ℃, arranging a Venturi mixer in a gas-liquid mixer 4, feeding chloroethylene according to the feeding amount of the mol ratio of chloroethylene to carbon tetrachloride of 1:2.9, fully mixing the chloroethylene with pumped and circulated liquid materials in the Venturi mixer, adding the mixture into the intensified reactor 2, controlling the pressure of the reactor to be 1.48MPa, in the reaction process, generating ferrous chloride (excessive iron filler and avoiding generating ferric chloride) by the free radical reaction of iron theta ring filler and carbon tetrachloride and a small amount of water in a system, improving the telomerization reaction rate as a catalyst, sampling and analyzing every 0.5h in the reaction process, and stopping the reaction when the conversion rate of carbon tetrachloride reaches 34%;

3) adding the reaction liquid obtained in the step 2) into a first rectifying tower 5, controlling the temperature of a tower bottom of the first rectifying tower 5 to be 87.7 ℃, controlling the pressure of the first rectifying tower 5 to be 9.7kPa, recovering vinyl chloride, carbon tetrachloride and an auxiliary agent (ethanol) fraction obtained at the tower top in the rectifying process, and feeding the crude 1,1,1,3, 3-pentachloropropane obtained at the tower bottom into a second rectifying tower 6 for high vacuum rectification;

4) controlling the temperature of the tower bottom of the second rectifying tower 6 to be 99.3 ℃, the rectifying pressure to be 890Pa, rectifying the crude 1,1,1,3, 3-pentachloropropane in the second rectifying tower for 2.0h under high vacuum, obtaining the 1,1,1,3, 3-pentachloropropane at the tower top, wherein the yield is 91 percent, the purity is 99.8 percent, and recovering residual liquid at the tower bottom.

Example 2

The difference between the embodiment and the embodiment 1 is that vinyl chloride, carbon tetrachloride and assistant fractions obtained at the top of the tower in the step 3) are recycled to the step (1) for reuse, 80% of residual liquid in the tower bottom of the second rectifying tower 6 is recycled to the step (2) for reuse, and after the cyclic reaction is carried out once, 1,1,1,3, 3-pentachloropropane is finally obtained at the top of the second rectifying tower 6, the yield is 96%, and the purity is 99.8%.

Example 3

This example differs from example 1 in that the reaction is carried out without the addition of auxiliary agents, and samples are analyzed in step 2) to find that carbon tetrachloride is not substantially converted.

Example 4

The difference between the embodiment and the embodiment 2 is that in the step 1), the molar ratio of ethanol to carbon tetrachloride is 0.005:1, the mixture is preheated to 60.2 ℃, and the mixing time in the strengthening reactor 2 is 3 hours; in the step 2), the temperature of the enhanced reactor 2 is raised to 138.5 ℃, vinyl chloride is introduced into the enhanced reactor 2 for forced circulation reaction at a feeding amount of a molar ratio of vinyl chloride to carbon tetrachloride of 1:1.5, the pressure of the reactor is 0.51MPa, samples are taken for analysis every 0.5h in the reaction process, and the reaction is stopped when the conversion rate of carbon tetrachloride reaches 66%; in the step 3), the temperature of the tower bottom 5 of the first rectifying tower is 60.6 ℃, and the rectifying pressure is 1.5 kPa; in the step 4), the temperature of the bottom of the second rectifying tower 6 is 70.2 ℃, the rectifying pressure is 200Pa, and finally the 1,1,1,3, 3-pentachloropropane is obtained at the top of the second rectifying tower 6, the yield is 90%, and the purity is 99.8%.

Example 5

The difference between the embodiment and the embodiment 2 is that in the step 1), the molar ratio of ethanol to carbon tetrachloride is 0.025:1, the mixture is preheated to 66.2 ℃, and the mixing time in the strengthening reactor 2 is 4.5 h; in the step 2), the temperature of the intensified reactor 2 is raised to 65.9 ℃, chloroethylene is introduced into the intensified reactor 2 for forced circulation reaction at the feeding amount of the mol ratio of 1:2.2 of chloroethylene to carbon tetrachloride, the pressure of the reactor is 1.01MPa, sampling analysis is carried out every 0.5h in the reaction process, and the reaction is stopped when the conversion rate of the carbon tetrachloride reaches 45%; in the step 3), the temperature of the tower bottom 5 of the first rectifying tower is 74.7 ℃, and the rectifying pressure is 5.7 kPa; in the step 4), the temperature of the bottom of the second rectifying tower 6 is 84.8 ℃, the rectifying pressure is 540Pa, and finally the 1,1,1,3, 3-pentachloropropane is obtained at the top of the second rectifying tower 6, the yield is 94%, and the purity is 99.8%.

Example 6

The difference between the embodiment and the embodiment 2 is that a porous iron packed bed stacked by saddle ring iron packing is filled in the strengthening reactor 2, the auxiliary agent is 12-crown ether-4, the molar ratio of 12-crown ether-4 to carbon tetrachloride in the step 1) is 0.025:1, the mixture is preheated to 66.4 ℃, and the mixing time in the strengthening reactor 2 is 4.5 hours; in the step 2), the temperature of the enhanced reactor 2 is raised to 65.7 ℃, chloroethylene is introduced into the enhanced reactor 2 for forced circulation reaction at the feeding amount of the mol ratio of the chloroethylene to the carbon tetrachloride of 1:2.2, the pressure of the reactor is 1.00MPa, sampling analysis is carried out every 0.5h in the reaction process, and the reaction is stopped when the conversion rate of the carbon tetrachloride reaches 45%; in the step 3), the temperature of the tower bottom 5 of the first rectifying tower is 73.6 ℃, and the rectifying pressure is 5.6 kPa; in the step 4), the temperature of the bottom of the second rectifying tower 6 is 83.9 ℃, the rectifying pressure is 530Pa, and finally the 1,1,1,3, 3-pentachloropropane is obtained at the top of the second rectifying tower 6, the yield is 84%, and the purity is 99.7%.

Example 7

The difference between the embodiment and the embodiment 2 is that a porous iron packed bed with iron pall ring packing stacked is filled in the strengthening reactor 2, 12-crown ether-4 is selected as the auxiliary agent, the molar ratio of 12-crown ether-4 to carbon tetrachloride in the step 1) is 0.025:1, the mixture is preheated to 66.5 ℃, and the mixing time in the strengthening reactor 2 is 4.5 hours; in the step 2), the temperature of the intensified reactor 2 is raised to 65.9 ℃, chloroethylene is introduced into the intensified reactor 2 for forced circulation reaction at the feeding amount of the mol ratio of 1:2.2 of chloroethylene to carbon tetrachloride, the pressure of the reactor is 1.01MPa, sampling analysis is carried out every 0.5h in the reaction process, and the reaction is stopped when the conversion rate of the carbon tetrachloride reaches 45%; in the step 3), the temperature of the tower bottom 5 of the first rectifying tower is 72.9 ℃, and the rectifying pressure is 5.6 kPa; in the step 4), the temperature of the bottom of the second rectifying tower 6 is 83.1 ℃, the rectifying pressure is 530Pa, and finally, the 1,1,1,3, 3-pentachloropropane is obtained at the top of the second rectifying tower 6, the yield is 81 percent, and the purity is 99.7 percent.

The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above-mentioned embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may be made by those skilled in the art without departing from the principle of the invention.

Claims

1. A preparation method of 1,1,1,3, 3-pentachloropropane is characterized by mainly comprising the following steps:

(1) preheating the carbon tetrachloride and auxiliary agent mixture, adding the preheated carbon tetrachloride and auxiliary agent mixture into a strengthening reactor, and performing forced circulation for a period of time;

(2) introducing chloroethylene into a reinforced reactor to perform forced circulation reaction;

(3) adding the reaction liquid after the forced circulation reaction in the step (2) into a first rectifying tower for rectification, obtaining carbon tetrachloride and an auxiliary agent at the top of the first rectifying tower, and obtaining crude 1,1,1,3, 3-pentachloropropane at the bottom of the tower;

(4) adding the crude 1,1,1,3, 3-pentachloropropane into a second rectifying tower for high vacuum rectification, obtaining the 1,1,1,3, 3-pentachloropropane at the top of the second rectifying tower, and recovering residual liquid in the tower bottom.

2. The method of claim 1, wherein: in the step (1), the carbon tetrachloride and the auxiliary agent are uniformly mixed and then preheated to 60-75 ℃, and the circulating reaction time of the mixture is 3-6 h.

3. The method of claim 2, wherein: the auxiliary agent is ethanol or 12-crown ether-4, and the molar ratio of the auxiliary agent to carbon tetrachloride is 0.005-0.05: 1.

4. The production method according to claim 3, characterized in that: in the step (2), the chloroethylene material is fully mixed with the liquid material in the Venturi mixer and then is sent into the strengthening reactor.

5. The method of claim 4, wherein: sampling and analyzing every 0.5h in the reaction process of the step (2), and stopping the reaction when the carbon tetrachloride conversion rate reaches 34-66%.

6. The method of claim 5, wherein: the reinforced reactor is a pipeline reactor with filler, iron theta ring filler or iron saddle ring filler or iron pall ring filler is filled in the reinforced reactor, and the filler is stacked into a porous iron filler bed structure.

7. The method of claim 6, wherein: in the step (2), the molar ratio of chloroethylene to carbon tetrachloride is 1: 1.5-3, the forced circulation reaction temperature is 65-140 ℃, and the reaction pressure is 0.5-2.5 MPa.

8. The method of claim 7, wherein: the temperature of a rectifying tower kettle of the first rectifying tower is 60-90 ℃, and the rectifying pressure is 1.5-10 kPa.

9. The method of claim 8, wherein: and (3) recycling the vinyl chloride, carbon tetrachloride and the auxiliary agent fraction obtained from the top of the first rectifying tower to the step (1) for reuse.

10. The method of claim 9, wherein: the temperature of a rectifying tower kettle of the second rectifying tower is 70-100 ℃, and the rectifying pressure is 200-900 Pa.

11. The method of manufacturing according to claim 10, wherein: and (3) discharging 5-25% of the residual liquid in the second rectifying tower as a waste liquid discharge system, and recycling the residual liquid of 75-95% to the step (2).