Catalyst recycling method and device system for preparing phthaloyl chloride by phosgene method
阅读说明：本技术 一种光气法制备苯二甲酰氯的催化剂回用方法及装置系统 (Catalyst recycling method and device system for preparing phthaloyl chloride by phosgene method ) 是由 李建峰 尚永华 朱付林 吴谦 程英 王鹏飞 俞勇 黎源 于 2020-05-27 设计创作，主要内容包括：本发明提供一种光气法制备苯二甲酰氯的催化剂回用方法及装置系统,所述回用方法通过两级分离设备使催化剂回收利用。相对传统工艺流程,本发明的酰氯催化剂回用工艺不但减少了废液的排放,实现了催化剂的循环利用,还减少了频繁排料导致的物料泄漏及污染,减轻了工人作业强度,改善现场作业环境和环保安全；本发明的回收装置系统设备投资少,操作简单,设计合理,催化剂循环次数多,酰氯反应液反应纯度高,有很高的经济效益和环境效益。(The invention provides a method and a device system for recycling a catalyst for preparing phthaloyl chloride by a phosgene method. Compared with the traditional process flow, the recycling process of the acyl chloride catalyst not only reduces the discharge of waste liquid and realizes the recycling of the catalyst, but also reduces material leakage and pollution caused by frequent discharge, lightens the operation intensity of workers, and improves the field operation environment and environmental protection safety; the recovery device has the advantages of less system equipment investment, simple operation, reasonable design, more catalyst circulation times, high reaction purity of acyl chloride reaction liquid and high economic benefit and environmental benefit.)
1. A catalyst recycling method for preparing phthaloyl chloride by a phosgene method is characterized by comprising the following steps:
1) preparing phthaloyl chloride by a phosgene method by taking DMF as a catalyst;
2) enabling the phthaloyl chloride reaction product liquid flow containing the catalyst to enter high-speed centrifugal separation equipment, and centrifugally separating the phthaloyl chloride reaction product liquid flow into a light component flow containing an acyl chloride dissolving solution and a recombinant flow mainly containing a catalyst solution by utilizing the density difference of two phases;
3) the light component flows through a light component liquid outlet and is sent into the acyl chloride solution storage tank, and the recombined split stream is sent into a membrane separation device to carry out secondary separation of the catalyst and the small amount of acyl chloride solution;
4) the catalyst is separated, and the separated catalyst enters the catalyst storage tank and is circulated to the reaction kettle in the first step to continuously participate in the reaction; the small amount of acid chloride solution was collected into the acid chloride solution reservoir.
2. The catalyst recycling method according to claim 1, wherein the high-speed centrifugal separation device in the step 2) is a high-speed cyclone separator, and the rotating speed of a high-speed rotating disc of the high-speed cyclone separator is 100-3000 rpm.
3. The catalyst recycling method according to claim 2, wherein the rotating speed of the high-speed rotating disc is 500-2500 rpm, and the flow rate of the material entering the high-speed cyclone separator is 0.5-3 m/s.
4. The catalyst recycling method according to claim 3, wherein the high-speed rotating disc comprises a rotating disc with a planar structure and liquid-stirring convex plates which are uniformly distributed and are protruded on the rotating disc.
5. The catalyst recycling method according to claim 4, wherein the liquid-repellent convex plate is 3-10 liquid-repellent convex plates, the liquid-repellent convex plates radially extend from the center of the rotating disc to the edge of the rotating disc, the raised liquid-repellent convex plates are in a fan blade-shaped structure, and the height of the liquid-repellent convex plates is 5 mm-200 mm.
6. The catalyst recycling method according to claim 1, wherein the membrane separation device in step 3) is a tubular membrane separation cartridge, the tubular membrane separation cartridge comprises a tube side of a filter tube and a shell side of a cavity, and the heavy component is sent to the tube side.
7. The catalyst recycling method according to claim 6, wherein the filter tube is made of PP, the surface of the filter tube is provided with sieve pores with the diameter of 5-50 mm, the surface of the filter tube is supported with a separation membrane, the separation membrane is an oleophobic hydrophilic membrane made of PTFE, the small amount of acyl chloride solution cannot permeate through the filter membrane, and the catalyst can permeate through the filter membrane to be separated.
8. The catalyst recycling method according to claim 7, wherein the separation membrane has a pore size of 0.1 to 5 μm and a thickness of 100 to 350 μm.
9. The method for recycling catalyst according to claim 7 or 8, wherein the pressure difference between the inside and the outside of the filter tube is 0.4kg/cm2To 1.5kg/cm2The length of the filter tube is 0.1-3 m, and the flow velocity of the recombined split flow entering the filter tube is 30-100 ml/min/cm2。
10. The catalyst recycling method according to claim 9, wherein the pressure difference between the inside and the outside of the filter tube is more than 4 times of the original pressure difference or less than 0.4kg/cm2In the meantime, the filtration membrane is replaced.
11. The catalyst recycling method according to claim 1, wherein the catalyst is discharged out of the system after being recycled for 20-40 times and replaced by a new catalyst.
12. The device system for recycling the phthaloyl chloride catalyst prepared by the phosgene method of any one of claims 1 to 11 is characterized by comprising an acyl chloride reaction kettle, a high-speed cyclone separator, a primary catalyst collecting tank, a tubular membrane separation cylinder, a secondary catalyst tank and an acyl chloride solution storage tank, wherein the high-speed cyclone separator comprises a feed inlet positioned at the bottom, a light component liquid outlet positioned at the upper part and a heavy component liquid outlet positioned at the top; the discharge hole of the acyl chloride reaction kettle is connected with the bottom feed inlet of the high-speed cyclone separator; the light component liquid outlet is connected with an acyl chloride solution storage tank; the heavy component liquid outlet is connected with the primary catalyst collecting tank; the first-stage catalyst collecting tank is connected with a feed inlet of the tubular membrane separation cylinder; the discharge hole at the bottom of the tubular membrane separation cylinder is connected with a secondary catalyst tank; a discharge port at the side part of the tubular membrane separation cylinder is connected with an acyl chloride solution storage tank; and the secondary catalyst tank is connected with the acyl chloride reaction kettle.
13. The apparatus system for recycling catalyst used in preparation of phthaloyl chloride by phosgene process according to claim 12, wherein the light component liquid outlet, the heavy component liquid outlet, and the bottom and side outlets of the tubular membrane separation cylinder of the high-speed cyclone separator are all provided with an on-line densitometer; the tubular membrane separation cylinder is provided with a pressure difference meter.
Technical Field
The invention relates to the technical field of acyl chloride synthesis, in particular to a method and a device system for recycling a catalyst for preparing phthaloyl chloride by a phosgene method.
Background
The phthaloyl chloride is one of the main monomers for synthesizing high-strength films and high-temperature resistant materials such as polyaramide, polyesteramide, polyarylate, polyarylsulfone and the like, and is widely applied to the aspects of pesticides, medicines, dyes, pigments and the like. The monomers are widely applied to the aspects of industrial materials, electric appliance insulating materials, protective clothing, interior decoration materials and the like, can be used as raw materials of polyamide for paint elimination, aromatic polyimide laminated high-temperature resistant materials, permeable membrane materials, polymer modifiers, dyes and the like, and can also be used for synthesizing pesticides, medicines and the like. Therefore, the phthaloyl chloride has wide market prospect. The preparation method mainly comprises a sulfoxide chloride method, a phosgene method, a phosphorus trichloride method, a phosphorus pentachloride method, an ester chlorination method and a paraxylene chlorination method.
At present, phthalic anhydride or phthalic acid is generally used as a raw material to react with a chlorinating agent to prepare the corresponding phthaloyl chloride. The reaction temperature of the thionyl chloride method production process is about 80 ℃, the reaction time is generally 8-12 hours, the yield is about 85%, but the prepared product has low quality and low purity, the melting point of the prepared terephthaloyl chloride is only about 80 ℃, the prepared terephthaloyl chloride cannot be directly used for the synthesis of artificial fibers, the pressure reduction distillation is often needed for several times to reach the specified index, in the post-treatment process of the method, thionyl chloride has certain corrosivity on equipment, the production cost is higher, in addition, the thionyl chloride has strong irritation, and the operation environment is severe.
In addition, the phosphorus pentachloride has strong chloridizing capacity and more side reactions, the product is not easy to separate and purify, and the phosphorus pentachloride is easy to absorb moisture in the air and decompose to release hydrogen chloride gas. The application of phosphorus trichloride is less, the reaction needs higher temperature and longer time, the process operation is relatively complex, the yield is low, a phosphorus oxychloride byproduct is also generated, and the phosphorus trichloride and the phosphorus oxychloride have higher corrosivity on equipment. The catalyst used in the chlorohydrocarbon process is zinc powder, aluminium powder, iron powder, anhydrous zinc chloride, ammonium chloride, ferric chloride, etc. it has the demerits that the chlorohydrocarbon is not environment friendly, and that the mixture of Lewis acid and organic side product is difficult to treat and the separation operation cost is high. The trichlorotoluene process has the disadvantage that benzoyl chloride by-products and Lewis acids are formed and the work-up is complicated. Chlorine is used as a chlorinating agent in the ester chlorination method, but methanol is consumed in the production process of dimethyl terephthalate as a raw material, the reaction temperature is high, the production period is long, ultraviolet light irradiation is often used in the reaction process, the release of tail gas in the reaction process causes great pollution to the environment, and phosgene is also released. The xylene chlorination method is mainly characterized in that the method starts from p-xylene with lower cost, an acid stage is not needed, but bis (trichloromethyl) benzene is generally needed to be prepared, so that the preparation process of the terephthaloyl chloride becomes complicated, the flow is prolonged, the method is not as convenient as the method for preparing the phthaloyl chloride by taking phthalic acid as a raw material, in addition, the reaction is carried out at higher temperature, the yield is lower, and simultaneously, the method also needs ultraviolet irradiation as the ester chlorination method, consumes a large amount of energy and has higher cost. Therefore, a new synthesis technology of terephthaloyl chloride is urgently needed to be researched, so that the preparation process of the terephthaloyl chloride meets the characteristics of simple process, environmental friendliness, low cost and the like.
The prior method for synthesizing the phthaloyl chloride mainly adopts a thionyl chloride method, has higher cost and is not suitable for the prior hundred thousand ton-grade industrial mass production. With the progress of the technology, the phosgene method is more mature, and the industrialization trend is more obvious. Phosgene is a highly toxic gas, but the current industrial synthesis and safety technical measures are mature, the automation degree is high, the production cost is low, and the problem of processing sulfur-containing tail gas without thionyl chloride is solved.
Patent US3184506 relates to a process for the preparation of acid chlorides, comprising isophthaloyl dichloride, terephthaloyl dichloride, 1, 4-cyclohexanoyl dichloride, 1-naphthoyl dichloride, p-nitrobenzoyl dichloride, especially in the special reaction and operation conditions, the process of preparing acid chlorides by the reaction of carboxylic acid and phosgene is catalyzed by dimethyl formamide (DMF) as a catalyst, and the problem of tar generation in the continuous production reaction process is well solved. Prior to this patent, all processes for the preparation of acid chlorides from carboxylic acids and phosgene used formamide as a catalyst, and these processes failed in continuous production due to tar formation.
Chinese patent CN1229325C discloses a method for preparing high-purity isophthaloyl dichloride, which uses isophthalic acid and a chlorinating agent as raw materials, and produces the high-purity isophthaloyl dichloride through chemical reaction and separation and refining processes under the condition of a catalyst, wherein the purity of the isophthaloyl dichloride can reach more than 99.8 percent.
China patent application CN104744232A of Hunan sea Li discloses that m-phthalic acid is used as raw material, N-phenyl-N-methylbenzamide or 4-dimethylamino pyridine is used as catalyst, dichloroethane or toluene, chlorobenzene and xylene are used as reaction solvent, and phosgene COCl is used2Reacting the m-phthalic acid raw material serving as a chlorinating agent, then using nitrogen to drive hydrogen chloride gas generated by the reaction and unreacted chlorinating agent gas, and carrying out reduced pressure rectification to obtain the high-quality m-phthalic acid chloride with the mass percentage content of more than 99.95%.
In the prior art, the phosgene method is adopted for acyl chloride production, the catalyst DMF is mostly enriched to heavy components in the post-treatment process at present, and the catalyst used by chemical manufacturers is mostly disposable at present and is directly discharged as waste. Because the waste catalyst belongs to dangerous solid waste, a special unit must be entrusted to carry out incineration and other treatments, and a large amount of nitrogen-containing tail gas is generated. Such treatment not only increases the production cost, but also causes environmental pollution. In view of the fact that the catalyst recycling of the phosgene method acyl chloride production process is reported in the prior art, in order to improve economic benefits and environmental benefits and boost the large-scale application of the phosgene method acyl chloride process, the research on the recycling of the catalyst in the process is very necessary.
Disclosure of Invention
The invention aims to overcome the defects of the prior art, uses phosgene to replace traditional chlorinating agents such as thionyl chloride, phosphorus oxychloride and phosphorus trichloride to react with phthalic acid to prepare phthaloyl chloride, and particularly provides a recycling method and a recycling device system of an acyl chloride catalyst, wherein the recycling method and the recycling device system can save the catalyst dosage by more than 95 percent, thereby reducing the production cost, reducing the environmental hazard, improving the operation environment and realizing the environment-friendly and operation-friendly production process.
In order to achieve the technical effects, the invention adopts the following technical scheme:
a catalyst recycling method for preparing phthaloyl chloride by a phosgene method is characterized by comprising the following steps:
1) preparing phthaloyl chloride by a phosgene method by taking DMF as a catalyst;
2) enabling the phthaloyl chloride reaction product liquid flow containing the catalyst to enter high-speed centrifugal separation equipment, and centrifugally separating the phthaloyl chloride reaction product liquid flow into a light component flow containing an acyl chloride dissolving solution and a recombinant flow mainly containing a catalyst solution by utilizing the density difference of two phases;
3) the light component flows through a light component liquid outlet and is sent into the acyl chloride solution storage tank, and the recombined split stream is sent into a membrane separation device to carry out secondary separation of the catalyst and the small amount of acyl chloride solution;
4) the catalyst is separated, and the separated catalyst enters the catalyst storage tank and is circulated to the reaction kettle in the first step to continuously participate in the reaction; the small amount of acid chloride solution was collected into the acid chloride solution reservoir.
The high-speed centrifugal separation equipment in the step 2) is a high-speed cyclone separator, and the rotating speed of a high-speed rotating disc of the high-speed cyclone separator is 100-3000 rpm.
The rotating speed of the high-speed rotating disc is 500-2500 rpm, and the flow speed of the materials entering the high-speed cyclone separator is 0.5-3 m/s.
The high-speed rotating disc comprises a rotating disc with a plane structure and a liquid stirring convex plate which is uniformly distributed and is protruded on the rotating disc.
The liquid stirring convex plates are 3-10 liquid stirring convex plates which are uniformly distributed at intervals, the liquid stirring convex plates radially extend to the edge of the rotating disc from the center of the rotating disc, the raised liquid stirring convex plates are of fan blade-shaped structures, and the height of each liquid stirring convex plate is 5-200 mm.
Wherein, the membrane separation device in the step 3) is a tubular membrane separation cylinder, the tubular membrane separation cylinder comprises a tube pass of a filter tube and a shell pass of a cavity, and the heavy component is sent to the tube pass.
The filter tube is made of PP materials, the surface of the filter tube is provided with sieve pores with the diameter of 5-50 mm, the surface of the filter tube is supported with a separation membrane, the separation membrane is an oleophobic hydrophilic membrane made of PTFE materials, a small amount of acyl chloride solution cannot permeate through the filter membrane, and the catalyst can permeate through the filter membrane to be separated.
Wherein the aperture of the separation membrane is 0.1-5 μm, and the thickness is 100-350 μm.
Wherein the pressure difference between the inside and the outside of the filter pipe is 0.4kg/cm2To 1.5kg/cm2The length of the filter pipe is 1.2m, and the flow velocity of the recombined split flow entering the filter pipe is 30-100 ml/min/cm2。
Wherein the pressure difference between the inside and the outside of the filter pipe is more than 4 times of the original pressure difference or the pressure difference is less than 0.4kg/cm2In the meantime, the filtration membrane is replaced.
And discharging the catalyst out of the system after the catalyst is recycled for 20-40 times, and replacing the catalyst with a new catalyst.
On the other hand, the invention provides a device system for recycling the phthaloyl chloride catalyst prepared by the phosgene method, which is characterized by comprising an acyl chloride reaction kettle 1, a high-speed cyclone separator 3, a primary catalyst collecting tank 11, a tubular membrane separation cylinder 13, a secondary catalyst tank 16 and an acyl chloride solution storage tank 19, wherein the high-speed cyclone separator 3 comprises a feed inlet 4 positioned at the bottom, a light component liquid outlet 7 positioned at the upper part and a heavy component liquid outlet 9 positioned at the top; the discharge hole of the acyl chloride reaction kettle 1 is connected with the bottom feed inlet 4 of the high-speed cyclone separator 3; the light component liquid outlet 7 is connected with an acyl chloride solution storage tank 19; the heavy component liquid outlet 9 is connected with a primary catalyst collecting tank 11; the first-stage catalyst collecting tank 11 is connected with a feed inlet of a tubular membrane separation cylinder 13; the discharge hole at the bottom of the tubular membrane separation cylinder 13 is connected with a secondary catalyst tank 16; a discharge port at the side part of the tubular membrane separation cylinder 13 is connected with an acyl chloride solution storage tank 19; the secondary catalyst tank 16 is connected with the acyl chloride reaction kettle 1.
Wherein the light component liquid outlet 7, the heavy component liquid outlet 9 and the bottom discharge port and the side discharge port of the tubular membrane separation cylinder 13 of the high-speed cyclone separator 3 are all provided with an online densimeter; the tubular membrane separation cylinder 13 is provided with a pressure difference gauge 20.
By adopting the technical scheme, the invention has the following beneficial effects:
(1) the method for recycling the acyl chloride catalyst can quickly, simply and conveniently control the quality of raw materials, discover the slight difference of the raw materials, reduce the dosage of the catalyst by more than 95 percent and prepare the acyl chloride with excellent performance at lower cost and higher efficiency.
(2) The acyl chloride catalyst recycling device system of this equipment, the core equipment handling capacity is big and separation efficiency is high, and equipment is small, and dwell time is shorter, generally within 5 ~ 30 minutes, and the liquid holdup is little to reach the big and obvious technological effect of treatment effect of separation handling capacity.
(3) Compared with the prior art, the method and the device system for recycling the acyl chloride catalyst have the advantages of small effective volume of equipment, high automation degree, simple process, low cost, environmental friendliness, friendly operation, good recycling effect, high reaction yield, low production cost, easy realization of industrial production, and great implementation value and social, economic and environmental benefits.
Drawings
FIG. 1 is a schematic view of the flow and structure of the catalyst recycling device system of the present invention.
FIG. 2 is a schematic top view of the rotating disk of the high-speed cyclone separator of the present invention.
FIG. 3 is a schematic side view of the rotating disk of the high-speed cyclone separator of the present invention.
Wherein, 1 is acyl chloride reation kettle, 2 reaction liquid delivery pumps, 3 high-speed cyclone, 4 bottom feed inlets, 5 motor and drive mechanism, 6 spinning disk, 7 light component leakage fluid dram, 8 on-line densimeters, 9 heavy ends liquid outlet, 10 on-line densimeters, 11 one-level catalyst collection tanks, 12 delivery pumps, 13 tubular membrane separation section of thick bamboo, 14 oleophobic filter membrane pipe, 15 on-line densimeters, 16 second grade catalyst jar, 17 catalyst delivery pumps, 18 on-line densimeters, 19 acyl chloride solution storage tanks, 20 differential pressure table, 201 whirl disc, 202 transmission shaft, 203 feed inlets, 204 stir liquid convex plate.
Detailed Description
The following examples will further illustrate the method provided by the present invention in order to better understand the technical solution of the present invention, but the present invention is not limited to the listed examples, and also includes any other known modifications within the scope of the claims of the present invention.
The device system for recycling the phthaloyl chloride catalyst prepared by the phosgene method is characterized by comprising an acyl chloride reaction kettle 1, a high-speed cyclone separator 3, a primary catalyst collecting tank 11, a tubular membrane separation cylinder 13, a secondary catalyst tank 16 and an acyl chloride solution storage tank 19, wherein the high-speed cyclone separator 3 comprises a feed inlet 4 positioned at the bottom, a light component liquid outlet 7 positioned at the upper part and a heavy component liquid outlet 9 positioned at the top; the discharge hole of the acyl chloride reaction kettle 1 is connected with the bottom feed inlet 4 of the high-speed cyclone separator 3; the light component liquid outlet 7 is connected with an acyl chloride solution storage tank 19; the heavy component liquid outlet 9 is connected with a primary catalyst collecting tank 11; the first-stage catalyst collecting tank 11 is connected with a feed inlet of a tubular membrane separation cylinder 13; the discharge hole at the bottom of the tubular membrane separation cylinder 13 is connected with a secondary catalyst tank 16; a discharge port at the side part of the tubular membrane separation cylinder 13 is connected with an acyl chloride solution storage tank 19; the secondary catalyst tank 16 is connected with the acyl chloride reaction kettle 1.
As understood by those skilled in the art, the connection means that two reactors or devices or storage tanks are directly or indirectly connected through one or more pipelines, and inevitably valves including, but not limited to, pumps, valves, flow meters, densitometers, pressure meters, thermometers, etc., electrical meters or other control devices can be arranged according to actual control requirements; auxiliary equipment or facilities such as an intermediate storage tank, a buffer tank or a heat exchanger can be arranged between the two connected main equipment according to the requirement. The connection described herein is intended to convey the flow of material between the primary devices only and should be within the scope of the present invention, whether directly or indirectly connected. In the process of the present invention, the pipeline material is preferably modified polypropylene, and the equipment casing is preferably enamel.
For example, as shown in fig. 1, the apparatus system for preparing phthaloyl chloride catalyst by phosgene method comprises a 1 acyl chloride reaction kettle, a 3 high-speed cyclone separator, 11 primary catalyst collection tanks, 13 tubular membrane separation cylinders, a secondary catalyst tank, and 19 acyl chloride solution storage tanks. The high-speed cyclone separator 3 comprises a feed inlet 4 positioned at the bottom, a light component liquid outlet 7 positioned at the upper part and a heavy component liquid outlet 9 positioned at the top, and the cyclone disc 6 is driven to rotate at a high speed by a motor and a transmission mechanism 5; the discharge hole of the acyl chloride reaction kettle 1 is connected with the bottom feed inlet 4 of the high-speed cyclone separator 3 through a reaction liquid delivery pump 2; the light component liquid outlet 7 is connected with an acyl chloride solution storage tank 19 through an online densimeter 8; the heavy component liquid outlet 9 is connected with a first-stage catalyst collecting tank 11 through an online densimeter 10; the primary catalyst collecting tank 11 is connected with a feed inlet of a tubular membrane separation cylinder 13 through a delivery pump 12; the tubular membrane separation cylinder 13 comprises a tube side of an oleophobic filter membrane tube 14 distributed in the interior and a shell side of a cavity, a pressure difference meter 20 for monitoring the pressure difference of the oleophobic filter membrane tube 14, a discharge hole at the bottom and a discharge hole at the side, and the discharge hole at the bottom of the tubular membrane separation cylinder 13 is connected with a secondary catalyst tank 16 through an online densimeter 15; a discharge port at the side part of the tubular membrane separation cylinder 13 is connected with an acyl chloride solution storage tank 19 through an online densimeter 18; the secondary catalyst tank 16 is connected with the acyl chloride reaction kettle 1 through a catalyst delivery pump 17, so that the catalyst can be recycled.
According to the device system for recycling the phthaloyl chloride catalyst prepared by the phosgene method, the light component liquid outlet 7, the heavy component liquid outlet 9, the bottom discharge hole and the side discharge hole of the tubular membrane separation cylinder 13 are respectively provided with the double-flange differential pressure densimeter, the distribution of the catalyst liquid is monitored at any time through the online densimeter, the quality of the raw materials can be rapidly and simply controlled, the slight difference of the raw materials is found, and the acyl chloride product with excellent performance is guaranteed.
Correspondingly, the invention provides a method for recycling a catalyst for preparing phthaloyl chloride by a phosgene method, which comprises the following steps:
1) the phthaloyl chloride is prepared by a phosgene method by taking DMF as a catalyst.
In a specific embodiment, the specific process conditions for preparing phthaloyl chloride by the phosgene method can adopt a method disclosed in the self-owned patent CN1229325C of the company to synthesize an acid chloride reaction liquid by the phosgene method. The dosage ratio of the catalyst can be selected according to the product process, and generally, the dosage of the catalyst is within 0.01-10%. The solvent used for the reaction is generally chlorobenzene or o-dichlorobenzene. The content of the catalyst in the acyl chloride reaction solution obtained after the reaction is 0.01-10 wt% based on the total weight of the product.
2) The flow of the phthaloyl chloride reaction product containing the catalyst enters high-speed centrifugal separation equipment, and is centrifugally separated into a light component flow containing an acyl chloride dissolving solution and a recombinant flow mainly containing a catalyst solution by utilizing the density difference of two phases.
Through the step, acyl chloride reaction liquid containing the catalyst enters a high-speed centrifugal separator, and the aim of separation is fulfilled by utilizing the density difference of two phases and the difference of centrifugal force of the two phases in the mixed liquid rotating at high speed. By controlling relevant parameters, such as material flow rate and rotational speed of centrifugal separation, preliminary separation of light components and heavy components is achieved in a centrifuge, so that the light component liquid contains only a solution of acid chloride, and the heavy component liquid contains mainly a catalyst solution, but inevitably a small amount of acid chloride product. In the method of the invention, the amount of catalyst in the heavy component content obtained after the first-stage separation is 90-99.5 wt%, preferably 95-98 wt%, based on the total amount. At the same time, the heavies stream contains less than 10%, 5%, 2%, 1%, or 0.5% acid chloride product or less. The content of light components obtained after the first-stage separation in this step is 80 to 99 wt%, preferably 85 to 95 wt%, based on the total amount of the reaction solution; the balance is heavy components, and the content of the obtained heavy components is 1-20 wt%, preferably 5-15 wt% based on the total weight of the reaction solution.
In a specific embodiment, the high-speed centrifugal separation equipment is a high-speed cyclone separator, and the rotating speed of a high-speed rotating disc of the high-speed cyclone separator is 100-3000 rpm, preferably 500-2500 rpm; the flow rate of the materials of the acyl chloride reaction liquid entering the high-speed cyclone separator is 0.5-3 m/s.
As shown in fig. 1, the high-speed cyclone separator 3 comprises a cyclone disk 6 at the center, a separating drum and a cylindrical compartment area at the periphery, a feed inlet 4 at the bottom, a light fraction discharge outlet 7 at the upper part and a heavy fraction discharge outlet 9 at the top, wherein the cyclone disk 6 is driven to rotate at a high speed by a motor and a transmission mechanism 5. The motor can be a variable frequency motor, and the motor mainly has the functions of providing different speeds to drive the equipment to rotate, increasing the turbulent motion strength of liquid and shortening the diffusion distance. The transmission mechanism includes a motor double bearing housing and a drive shaft supported by the double bearing housing, one end of the drive shaft being connected to the rotating disk such that the rotating disk rotates at the speed of the drive shaft.
In a preferred embodiment, fig. 2 and fig. 3 show a specific structure form of a high-speed cyclone separator, the high-speed rotating disc 6 comprises rotational flow discs 201, 202 with a plane structure, drive shafts, 203 feed inlets and liquid-stirring convex plates 204 which are uniformly distributed at intervals and are protruded on the rotational flow discs 201, at least one feed inlet 203 is uniformly arranged on the surface of the rotational flow disc 201, and the feed inlet 203 is connected with a feed inlet 4 arranged at the bottom of the high-speed cyclone separator 3. More preferably, the liquid stirring convex plates are 3-10 liquid stirring convex plates, the liquid stirring convex plates radially extend to the edge of the rotating disc from the center of the rotating disc, the raised liquid stirring convex plates are of fan blade-shaped structures, and the height of each liquid stirring convex plate is 5-200 mm.
The acyl chloride reaction solution containing the catalyst is separated by high-speed centrifugal separation equipment, and the separation equipment is preferably made of a perfluorinated high polymer material and can resist strong acid corrosion. Reaction liquid materials are fed from the bottom and enter the separation rotary drum under the action of a rotary disc driven by a motor, the mixed liquid quickly rotates synchronously with the rotary disc, and the catalyst liquid with high density gradually leaves away from the center of the rotary shaft and leans against the wall of the rotary drum in the upward flowing process under the action of centrifugal force; the light phase liquid with smaller specific gravity gradually gets away from the wall of the rotary drum and leans to the center, and the clarified two-phase liquid finally enters the collection chamber through the weir plates and is respectively led out of the machine through the leading pipes, so that the two-phase separation process is completed.
In a specific embodiment, the rotating speed of the high-speed rotating disc is generally 100 to 3000rpm, preferably 500 to 2000rpm according to the requirement of the separation ratio content. The flow velocity of the material entering the high-speed cyclone separator is 0.5-3 m/s.
3) And the light component flows through a light component liquid outlet and is sent into the acyl chloride solution storage tank, and the recombined split stream is sent into a membrane separation device for secondary separation of the catalyst and the small amount of acyl chloride solution.
In a specific embodiment, the membrane separation device is a tubular membrane separation cartridge, the tubular membrane separation cartridge comprises a tube side of a filter tube and a shell side of a cavity, and is similar to a tubular heat exchanger structure, for example, a plurality of filter tubes which are parallel to each other are arranged in the interior of the separation cartridge, a separation membrane is wound on the filter tubes, for example, the number of the filter tubes which are parallel to each other is 5-20 or more, and the separation between the filter tubes is, for example, 2-8cm, but is not limited thereto. And (3) sending the heavy component into a tube pass, and further obtaining the catalyst without acyl chloride through membrane separation. In the secondary separation step of the invention, the separation of the catalyst and a small amount of acyl chloride solution is carried out by adopting a separation membrane element.
In a preferred embodiment, the filtering pipe is made of PP material, the surface of the filtering pipe is provided with a sieve pore with the diameter of 5-50 mm, and the surface of the filtering pipe is wound with a separation membrane, the pore diameter of the separation membrane is 0.1-5 μm, the thickness of the separation membrane is 100-350 μm, and the preferred thickness is 150-190 μm. The separation membrane can be wound or coated on the outer surface of the filter pipe, also can be arranged on the inner surface of the filter pipe, and is preferably wound on the outer surface of the filter pipe for convenient replacement. The separation membrane is an oleophobic hydrophilic membrane made of PTFE material, for example, an MSPTFE100LX filtration membrane of Mebothri biomembrane technology Limited is selected, the small amount of acyl chloride solution can not permeate the filtration membrane, the catalyst can permeate the filtration membrane to be separated, the separated catalyst is enriched at the bottom and is sent to a secondary catalyst tank 16, and the catalyst can also be recycled in a reaction kettle; the light component is an acyl chloride solution, which is collected and sent to an acyl chloride solution storage tank 19, and may be further sent to a separation system to obtain a product with higher purity.
In a preferred embodiment, the pressure drop inside and outside the filter tube is controlled to be 0.5kg/cm, and the pressure drop between the inner and outer walls of the filter tube is controlled to be 0.5kg/cm2The maximum pressure drop allowed by the filter is 1.5kg/cm2. I.e. the pressure difference between the inside and the outside of the filter tube is usually between 0.4kg/cm2To 1.5kg/cm2The length of the filter tube is 0.1-3 m, and the flow rate is 30-100 ml/min/cm2Preferably, the flow rate is 50-80 ml/min/cm2(ii) a When the internal and external pressure difference of the filter pipe is more than 4 times of the original pressure difference or the pressure difference is less than 0.4kg/cm2In the meantime, the filtration membrane is replaced.
4) The catalyst is separated, and the separated catalyst enters the catalyst storage tank and is recycled for later use; the small amount of acid chloride solution was collected into the acid chloride solution reservoir.
In another aspect of the present invention, the present invention provides a method for preparing acyl chloride by a phosgene method with a catalyst recycled, comprising the following steps:
1) preparing phthaloyl chloride by a phosgene method by taking DMF as a catalyst;
2) enabling the phthaloyl chloride reaction product liquid flow containing the catalyst to enter high-speed centrifugal separation equipment, and centrifugally separating the phthaloyl chloride reaction product liquid flow into a light component flow containing an acyl chloride dissolving solution and a recombinant flow mainly containing a catalyst solution by utilizing the density difference of two phases;
3) the light component flows through a light component liquid outlet and is sent into the acyl chloride solution storage tank, and the recombined split stream is sent into a membrane separation device to carry out secondary separation of the catalyst and the small amount of acyl chloride solution;
4) the catalyst is separated, and the separated catalyst enters the catalyst storage tank and is circulated to the reaction kettle in the first step to continuously participate in the reaction; the small amount of acid chloride solution was collected into the acid chloride solution reservoir.
In the embodiment, the catalyst components obtained by secondary separation and collection are recycled to the reaction kettle in the first step to continuously participate in the reaction, so that the discharge of waste liquid is reduced, the cyclic utilization of the catalyst is realized, and the additional value of products is further improved. And separating the light component without the catalyst under vacuum to recover the solvent and other light and heavy component impurities, thereby obtaining the high-quality isophthaloyl dichloride with the content of more than 99.95 percent.
In a preferred embodiment, in order to avoid the accumulation of impurities in the reacted catalyst, the catalyst is recycled for a certain number of times and then is discharged out of the reaction system, and the catalyst is replaced by fresh catalyst; preferably, the recycling is carried out for 20-40 times and the discharging is carried out for 1 time, and more preferably, the recycling is carried out for 25-30 times and the discharging is carried out for 1 time.
The following method for preparing o-, m-, and p-phthaloyl chloride by reacting phosgene with o-, m-, and p-phthalic acid is described in further detail by specific examples using phosgene as a chlorinating agent and DMF as a catalyst.
As shown in figure 1, the equipment used in the invention is a general chemical reaction kettle, a storage tank, a pump and the like, and the material is acid corrosion resistant material. The high-speed cyclone separator and the tubular membrane separation cylinder used in the method are manufactured by Wanhua Mucun machining company, the diameter of a rotating disk is 200mm, the rotating disk is a single layer, the volume of the separation cylinder is 100L, the power of a motor is about 5 kilowatts, and the rotating speed of a high-speed rotating bed is controlled to be 500-3000 r/min. The separation effect was monitored by an on-line densitometer.
The reaction liquid in the acyl chloride reaction kettle 1 is prepared according to a first-step phosgene method, and is conveyed to a bottom feed inlet 4 of a high-speed cyclone separator 3 through a reaction liquid conveying pump 2, the device is driven by a motor and a transmission mechanism 5, a cyclone disc 6 rotates at a high speed, acyl chloride solution with low density is discharged from a light component liquid discharge port 7 and is monitored by an online densimeter 8, and a catalyst solution is discharged from a heavy component liquid discharge port 9 and is monitored by an online densimeter 10. Heavy components are discharged to a first-stage catalyst collecting tank 11, and are conveyed to a tubular membrane separation cylinder 13 by a conveying pump 12, and the catalyst and a small amount of acyl chloride solution are separated by an oleophobic filter membrane tube 14.
The first-stage catalyst treatment liquid flows through a separation membrane to be further separated, and the catalyst passing through the filter membrane is enriched at the bottom, monitored by an online densimeter 15, stored in a second-stage catalyst tank 16 and recycled to the reaction kettle 1 by a catalyst delivery pump 17 for use. The acyl chloride solution which does not pass through the membrane is sent to an acyl chloride solution storage tank 19 through a pipeline and then sent to a separation system to remove the solvent, and then the product is obtained. A pressure difference meter 20 is arranged inside and outside the filter tube, and the state pressure difference of the filter membrane is monitored to be more than 1.5kg/cm2Or the pressure difference is less than 0.4kg/cm2And replacing the filtering membrane.
The following examples and comparative examples used starting materials to exclude the effect of known related impurities on the reaction.
The purity analysis of acyl chloride in the invention is carried out on gas chromatography, and HP6890 gas chromatography is adopted for analysis and detection, and the analysis and test conditions are as follows:
capillary chromatography column HP-5, 30m 0.33 mm;
sample injector temperature: 290 ℃;
nitrogen flow rate: 3.0 ml/min;
column temperature: the initial temperature is 100 ℃, the temperature programming rate is 20 ℃/min to the final temperature is 250 ℃, and the temperature is kept for 5 min;
hydrogen flame monitor temperature: 290 deg.c.
Example 1
75 parts of chlorobenzene, 25 parts of isophthalic acid and 2 parts of N, N-dimethylformamide are metered into a reactor provided with a stirring and sealing device, a temperature controller, a heating device, a phosgene metering device and a tail gas treatment device, and the reaction temperature is 75 ℃. And starting a stirring device and a tail gas treatment device, introducing phosgene, reacting until the solution is brownish yellow, wherein the reaction has no obvious heat release, the solid dicarboxylic acid is completely reacted, and the reaction is stopped when the reaction solution basically has no solid particles and slurry. The final reaction solution is a yellow solution, the upper layer is an acyl chloride chlorobenzene solution, the lower layer is a catalyst solution, and a part of mixed emulsion is arranged in the middle. Phosgene is removed at 50 ℃ using an inert gas such as nitrogen. Through gas chromatographic analysis, the content of the isophthaloyl dichloride in the product is more than 99.8 percent.
The reaction liquid is fed into a feed inlet of a high-speed cyclone separator, and the material flow rate is 0.5 m/s. Starting the cyclone separator and monitoring the online densimeter. The liquid convex plate of dialling of high-speed rotary disk of separator is 3 liquid boards of dialling, dials the liquid convex plate and is fan blade column structure evenly spaced apart distribution, dials liquid convex plate height and is 5 mm. The rotational speed of the spinning disk is adjusted to be 500rpm, and the densimeter is less than 1.179g/cm3And opening a light component liquid outlet, and sending the acyl chloride solution into an acyl chloride solution storage tank.
The density is more than 1.180g/cm3The heavy component enters a first-stage catalyst collection tank through a heavy component liquid outlet under the action of high-speed rotating centrifugal force, and is conveyed to a tubular membrane separation cylinder for secondary separation, the heavy component is conveyed to an oleophobic filter membrane pipe, and the catalyst permeates through a filter membrane and enters a second-stage catalyst tank through collection. A MSPTFE100LX filter membrane of Mebothri biomembrane technology Limited is selected, a filter tube supporting material is made of PP, a sieve pore with the diameter of 50mm is arranged on the surface, and a separation membrane with the pore diameter of 0.1 mu m is made of PTFE. The thickness of the filter membrane is 100 μm, the length of the filter tube is 0.1m, and the flow rate is 30ml/min/cm2. Controlling the density to make the pressure difference between the inside and the outside of the filter membrane less than 1.5kg/cm2Greater than 0.4kg/cm2. Collecting the acyl chloride solution which does not pass through the oleophobic membrane to an acyl chloride solution storage tank, wherein the density of the stream is less than 1.179g/cm3。
And (3) carrying out vacuum distillation on the materials in the acyl chloride solution storage tank under the distillation pressure of 100mbar and the distillation temperature of 80 ℃ to remove chlorobenzene, and then carrying out vacuum rectification under the distillation pressure of 10mbar and the kettle temperature of 160 ℃ to obtain a white substance, namely the isophthaloyl dichloride product.
The separated catalyst solution is circulated to the acyl chloride reaction kettle for continuous reaction and recycling, 40 batches of circulation is carried out, the obtained reaction solution is analyzed by gas chromatography, and specific experimental results are shown in table 1.
TABLE 1
Example 2
The raw materials and the synthesis and separation process of the prepared isophthaloyl dichloride are basically the same as those in example 1, wherein the addition amount of the catalyst and the reaction temperature are also the same.
The reaction liquid is fed into a feed inlet of a high-speed cyclone separator, and the material flow rate is 1.2 m/s. Starting the cyclone separator and monitoring the online densimeter. The liquid convex plate of dialling of high-speed rotary disk of separator is 8 and dials the liquid board, dials the liquid convex plate and is fan blade column structure evenly spaced apart distribution, dials liquid convex plate height and is 45 mm. The rotational speed of the spinning disk is adjusted to be 1500rpm, and the densimeter is less than 1.179g/cm3And opening a light component liquid outlet, and sending the acyl chloride solution into an acyl chloride solution storage tank.
The density is more than 1.180g/cm3The heavy component enters a first-stage catalyst collection tank through a heavy component liquid outlet under the action of high-speed rotating centrifugal force, and is conveyed to a tubular membrane separation cylinder for secondary separation, the heavy component is conveyed to an oleophobic filter membrane pipe, and the catalyst permeates through a filter membrane and enters a second-stage catalyst tank through collection. A MSPTFE100LX filtration membrane of Mebothri biomembrane technology Limited is selected, a support material of the filtration tube is a PP material, a sieve pore with the diameter of 40mm is arranged on the surface, and the aperture of the separation membrane is 3 mu m and is a PTFE material. The thickness of the filtration membrane was 200 μm, the length of the filtration tube was 1m, and the flow rate was 80ml/min/cm2. Controlling the density to make the pressure difference between the inside and the outside of the filter membrane less than 1.5kg/cm2Greater than 0.4kg/cm2. Collecting the acyl chloride solution which does not pass through the oleophobic membrane to an acyl chloride solution storage tank, wherein the density of the stream is less than 1.179g/cm3。
The separated catalyst solution is circulated to the acyl chloride reaction kettle for continuous reaction and recycling, 30 batches of circulation is carried out, the obtained reaction solution is analyzed by gas chromatography, and specific experimental results are shown in table 2.
TABLE 2
Batches of
Catalytic amount/%
Reaction temperature/. degree.C
Reaction time/min
Purity of reaction/%)
1
8
75
51
99.93
5
8
75
53
99.83
10
8
75
55
99.89
15
8
75
58
99.83
20
8
75
62
99.86
30
8
75
63
99.83
Example 3
The raw materials and the synthesis and separation process of the prepared isophthaloyl dichloride are basically the same as those in example 1, except that the addition amount of the catalyst and the reaction temperature are different, in this example, the catalyst amount is 5%, the DMF is 1.25 parts, and the reaction temperature is 70 ℃.
The reaction liquid is fed into a feed inlet of a high-speed cyclone separator, and the material flow rate is 3 m/s. Starting the cyclone separator and monitoring the online densimeter. The liquid-stirring convex plate of the high-speed rotating disc of the separator is 10 liquid-stirring plates, the liquid-stirring convex plate is of a fan blade-shaped structure, and the height of the liquid-stirring convex plate is 200 mm. The rotational speed of the rotational flow disk is adjusted to 2500rpm, and the density meter is less than 1.179g/cm3And opening a light component liquid outlet, and sending the acyl chloride solution into an acyl chloride solution storage tank.
The density is more than 1.180g/cm3The heavy component enters a first-stage catalyst collection tank through a heavy component liquid outlet under the action of high-speed rotating centrifugal force, and is conveyed to a tubular membrane separation cylinder for secondary separation, the heavy component is conveyed to an oleophobic filter membrane pipe, and the catalyst permeates through a filter membrane and enters a second-stage catalyst tank through collection. A MSPTFE100LX filter membrane of Mebothri biomembrane technology Limited is selected, a filter tube supporting material is made of PP, a sieve pore with the diameter of 30mm is arranged on the surface, and a separation membrane with the pore diameter of 5 mu m is made of PTFE. The thickness of the filter membrane was 350 μm, the length of the filter tube was 1.2m, and the flow rate was 80ml/min/cm2. Controlling the density to make the pressure difference between the inside and the outside of the filter membrane less than 1.5kg/cm2Greater than 0.4kg/cm2. Collecting the acyl chloride solution which does not pass through the oleophobic membrane to an acyl chloride solution storage tank, wherein the density of the stream is less than 1.179g/cm3。
The separated catalyst solution is circulated to the acyl chloride reaction kettle for continuous reaction and recycling, 40 batches of circulation is carried out, the obtained reaction solution is analyzed by gas chromatography, and specific experimental results are shown in table 2.
TABLE 3
Batches of
Catalytic amount/%
Reaction temperature/. degree.C
Reaction time/min
Purity of reaction/%)
1
5
70
85
99.89
5
5
70
82
99.84
10
5
70
83
99.87
15
5
70
78
99.85
20
5
70
76
99.85
30
5
70
80
99.83
40
5
70
77
99.80
Example 4
85 portions of o-dichlorobenzene, 15 portions of terephthalic acid and 0.75 portion of N, N-dimethylformamide are metered into a reactor provided with a stirring and sealing device, a temperature controller, a heating device, a phosgene metering device and a tail gas treatment device, and the reaction temperature is 80 ℃. And starting a stirring device and a tail gas treatment device, introducing phosgene, reacting until the solution is brownish yellow, wherein the reaction has no obvious heat release, the solid dicarboxylic acid is completely reacted, and the reaction is stopped when the reaction solution basically has no solid particles and slurry. The final reaction solution is a yellow solution, the upper layer is an acyl chloride chlorobenzene solution, the lower layer is a catalyst solution, and a part of mixed emulsion is arranged in the middle. Phosgene is removed at 50 ℃ using an inert gas such as nitrogen. The content of the terephthaloyl chloride in the product is more than 99.8 percent through gas chromatography analysis.
The reaction liquid is fed into a feed inlet of a high-speed cyclone separator, and the material flow rate is 0.5 m/s. Starting the cyclone separator and monitoring the online densimeter. The liquid-stirring convex plate of the high-speed rotating disc of the separator is 10 liquid-stirring plates, each liquid-stirring convex plate is of a fan blade-shaped structure, and the height of each liquid-stirring convex plate is 5 mm. The rotational speed of the spinning disk is adjusted to 2000rpm, and the densimeter is less than 1.311g/cm3And opening a light component liquid outlet, and sending the acyl chloride solution into an acyl chloride solution storage tank.
Heavy components with the density of more than 1.312g/cm3 enter a primary catalyst collecting tank through a heavy component liquid outlet under the action of high-speed rotating centrifugal force, and are conveyed to a tubular membrane separation cylinder for secondary separation, and the heavy components are conveyed to an oleophobic filter membrane tube. The catalyst permeates the filter membrane and enters a secondary catalyst tank after being collected. A MSPTFE100LX filter membrane of Mebothri biomembrane technology Limited is selected, a filter tube supporting material is made of PP, a sieve pore with the diameter of 5mm is arranged on the surface, and a separation membrane with the pore diameter of 4 mu m is made of PTFE. The thickness of the filter membrane was 190 μm, the length of the filter tube was 1.2m, and the flow rate was 100ml/min/cm2. The pressure difference between the inside and the outside of the filter membrane is controlled to be less than 1.5kg/cm2Greater than 0.4kg/cm2. Collecting the acyl chloride solution which does not pass through the oleophobic membrane to an acyl chloride solution storage tank, wherein the density of the stream is less than 1.311g/cm3。
And (3) carrying out vacuum distillation on the material in the terephthaloyl chloride solution storage tank under the distillation pressure of 100mbar and the distillation temperature of 80 ℃ to remove chlorobenzene, and then carrying out vacuum rectification under the distillation pressure of 13mbar and the distillation temperature of 130 ℃ to obtain a white substance, namely the terephthaloyl chloride product.
The separated catalyst solution is circularly returned to the acyl chloride reaction kettle for continuous reaction and recycling, 40 batches of circulation is carried out, the obtained reaction solution is analyzed by gas chromatography, and specific experimental results are shown in table 4.
TABLE 4
Batches of
Catalytic amount/%
Reaction temperature/. degree.C
Reaction time/min
Purity of reaction/%)
1
5
80
33
99.92
2
5
80
32
99.85
3
5
80
35
99.86
4
5
80
38
99.88
5
5
80
29
99.84
10
5
80
37
99.79
15
5
80
28
99.81
20
5
80
35
99.80
30
5
80
31
99.83
40
5
80
30
99.81
Example 5
The raw materials and the synthesis and separation process of the prepared terephthaloyl chloride are basically the same as those in example 4, wherein the catalyst addition amount and the reaction temperature are also the same.
The reaction liquid is fed into a feed inlet of a high-speed cyclone separator, and the material flow rate is 1.2 m/s. Starting the cyclone separator and monitoring the online densimeter. The liquid-stirring convex plate of the high-speed rotating disc of the separator is 8 liquid-stirring plates, each liquid-stirring convex plate is of a fan blade-shaped structure, and the height of each liquid-stirring convex plate is 10 mm. The rotational speed of the spinning disk is adjusted to be 1500rpm, and the densimeter is less than 1.311g/cm3And opening a light component liquid outlet, and sending the acyl chloride solution into an acyl chloride solution storage tank.
The density is more than 1.312g/cm3The heavy component enters a first-stage catalyst collecting tank through a heavy component liquid outlet under the action of high-speed rotating centrifugal force, and is conveyed to a tubular membrane separation cylinder for secondary separation, and the heavy component is conveyed to an oleophobic filter membrane tube. The catalyst permeates the filter membrane and enters a secondary catalyst tank after being collected. A MSPTFE100LX filter membrane of Mebothri biomembrane technology Limited is selected, a filter tube supporting material is made of PP, a sieve pore with the diameter of 45mm is arranged on the surface, and a separation membrane with the pore diameter of 3 mu m is made of PTFE. The thickness of the filter membrane is 300 μm, the length of the filter tube is 2m, and the flow rate is 30ml/min/cm2. The pressure difference between the inside and the outside of the filter membrane is controlled to be less than 1.5kg/cm2Greater than 0.4kg/cm2. Collecting the acyl chloride solution which does not pass through the oleophobic membrane to an acyl chloride solution storage tank, wherein the density of the stream is less than 1.311g/cm3。
The separated catalyst solution is circularly returned to the acyl chloride reaction kettle for continuous reaction and recycling, 40 batches of circulation is carried out, the obtained reaction solution is analyzed by gas chromatography, and specific experimental results are shown in table 5.
TABLE 5
Batches of
Catalyst and process for preparing sameAmount/%)
Reaction temperature/. degree.C
Reaction time/min
Purity of reaction/%)
1
5
80
30
99.90
5
5
80
28
99.93
10
5
80
33
99.90
15
5
80
34
99.84
20
5
80
37
99.83
30
5
80
35
99.84
40
5
80
38
99.79
Example 6
The raw materials and the steps of synthesis and separation of the prepared terephthaloyl chloride were substantially the same as in example 4, except that the amount of the catalyst added and the reaction temperature were different, in this example, the amount of the catalyst used was 3.5% and 0.525 parts of DMF, and the reaction temperature was 75 ℃.
The reaction liquid is fed into a feed inlet of a high-speed cyclone separator, and the material flow rate is 0.5 m/s. Starting the cyclone separator and monitoring the online densimeter. The liquid-stirring convex plate of the high-speed rotating disc of the separator is 4 liquid-stirring plates, the liquid-stirring convex plate is of a fan blade-shaped structure, and the height of the liquid-stirring convex plate is 150 mm. The rotational speed of the rotational flow disk is adjusted to 2500rpm, and the density meter is less than 1.311g/cm3And opening a light component liquid outlet, and sending the acyl chloride solution into an acyl chloride solution storage tank.
Heavy components with the density of more than 1.312g/cm3 enter a primary catalyst collecting tank through a heavy component liquid outlet under the action of high-speed rotating centrifugal force, and are conveyed to a tubular membrane separation cylinder for secondary separation, and the heavy components are conveyed to an oleophobic filter membrane tube. The catalyst permeates the filter membrane and enters a secondary catalyst tank after being collected. A MSPTFE100LX filter membrane of Mebothri biomembrane technology Limited is selected, a filter tube supporting material is made of PP, a sieve pore with the diameter of 15mm is arranged on the surface, and a separation membrane with the pore diameter of 5 mu m is made of PTFE. The thickness of the filter membrane was 350 μm, the length of the filter tube was 1m, and the flow rate was 50ml/min/cm2. The pressure difference between the inside and the outside of the filter membrane is controlled to be less than 1.5kg/cm2Greater than 0.4kg/cm2. Collecting the acyl chloride solution which does not pass through the oleophobic membrane to an acyl chloride solution storage tank, wherein the density of the stream is less than 1.311g/cm3。
The separated catalyst solution is circularly returned to the acyl chloride reaction kettle for continuous reaction and recycling, 40 batches of circulation is carried out, the obtained reaction solution is analyzed by gas chromatography, and specific experimental results are shown in table 6.
TABLE 6
Batches of
Catalytic amount/%
Reaction temperature/. degree.C
Reaction time/min
Purity of reaction/%)
1
3.5
75
59
99.88
5
3.5
75
63
99.86
10
3.5
75
69
99.80
15
3.5
75
64
99.81
20
3.5
75
66
99.82
30
3.5
75
68
99.81
40
3.5
75
70
99.78
According to the reaction time and the purity of the reaction liquid, the catalyst can be recycled, the stability of the recycled catalytic reaction system among batches is good, the quality of the reaction liquid is good, and the discharge of waste liquid is reduced.
The method and the device system for recycling the acyl chloride catalyst can save the catalyst consumption by more than 95 percent, reduce the production cost, reduce the environmental hazard, improve the operation environment and ensure that the synthesis process is environment-friendly and operation-friendly.
While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention. It will be appreciated by those skilled in the art that modifications or adaptations to the invention may be made in light of the teachings of the present specification. Such modifications or adaptations are intended to be within the scope of the present invention as defined in the claims.
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