KR102590777B1 - Method for producing terephthaloyl chloride through temperature control - Google Patents

Abstract

The present invention relates to a method for producing terephthaloyl chloride, and specifically, to produce terephthaloyl chloride by reacting hexachloroparaxylene at a plurality of temperature ranges depending on the conversion rate, and reacting the prepared hexachloroparaxylene with phthalic acid to produce terephthaloyl chloride. It relates to a method for producing terephthaloyl chloride, which produces monochloride.

Description

Method for producing terephthaloyl chloride through temperature control {Method for producing terephthaloyl chloride through temperature control}

The present invention relates to a method for producing terephthaloyl chloride through temperature control.

Terephthaloyl chloride (TPC) is a white solid or colorless needle-shaped crystal and is mainly used as a polymer monomer of poly(paraphenylene terephthamide) and polysulfonamide.

In addition, the terephthaloyl chloride has broad development and application prospects, such as being used as an admixture for high molecular weight polymers and as a heavy agent in the pesticide and pharmaceutical industries.

The method for producing terephthaloyl chloride, which has various uses as described above, typically involves a photoreaction step of paraxylene and chlorine gas using ultraviolet rays, and then reacting hexachloroparaxylene produced by the photoreaction with terephthalic acid in the presence of a catalyst. Methods for producing terephthaloyl chloride (also known as terephthaloyldichloride) are known.

However, as the concentration of hexachloroparaxylene generated in the photoreaction increases, the viscosity increases and the reaction rate may decrease. Accordingly, when reacting at a high temperature to lower the viscosity, the solubility of chlorine gas inside liquid para-xylene becomes very low, and thus the time to participate in the reaction is very short, so that it is discharged to the outside before reacting with para-xylene. Problems may arise.

In addition, when photoreacting paraxylene and chlorine gas, there is a problem that unreacted chlorine gas is discharged together with hydrochloric acid, a side reactant, causing environmental pollution. In other words, as mentioned above, in the case of hydrochloric acid, which is a side reactant, it can be easily removed by dissolving in water, but in the case of unreacted chlorine gas, excessive facilities are required to recover or store it when discharged to the outside, so it cannot be completely circulated in the reaction. There is a need for a new method to ensure that it is consumed in the reaction.

Republic of Korea Patent Publication No. 10-2019-0042664 (2019.04.24.)

The present invention was developed to solve the above-mentioned problems. By controlling the photoreaction temperature inside the reactor in producing hexachloroparaxylene, hexachloroparaxylene can maintain relatively high chlorine gas solubility within an appropriate viscosity. The purpose is to provide a method for producing xylene.

In addition, the present invention seeks to provide a method for producing hexachloroparaxylene in which chlorine gas is not discharged to the outside by completely consuming unreacted chlorine gas in the reaction without discharging it to the outside.

In addition, it is intended to provide terephthaloyl chloride by reacting the prepared hexachloroparaxylene with terephthalic acid.

The present invention relates to a method for producing hexachloroparaxylene by photoreacting paraxylene and chlorine gas, in which the photoreaction proceeds in four steps according to the increase in melting point of the intermediate product produced according to the conversion rate of hexachloroparaxylene. A method for producing hexachloroparaxylene, which is reacted in the above plurality of temperature ranges, is provided.

According to one aspect of the present invention, the hexachloroparaxylene production method may involve a plurality of reactors connected in parallel.

According to one aspect of the present invention, the plurality of reactors are reactors in which a first reactor and a second reactor are connected in parallel, and chlorine gas is continuously introduced into the first reactor filled with para-xylene to react and produce hexachloro-para-xylene. At the conversion rate of hexachloroparaxylene, where hydrochloric acid gas, which is a side-reactant due to conversion, is discharged to the outside, and chlorine gas continuously introduced from the first reactor where the reaction was started begins to be discharged as an unreacted product, the first Unreacted chlorine gas that is continuously introduced into the reactor and does not participate in the reaction is transferred to the second reactor without being discharged to the outside to initiate an initial reaction with para-xylene filled in the second reactor, and the reaction in the first reactor is terminated. The chlorine gas continuously injected into the first reactor is connected to the second reactor to start continuous input into the second reactor, and while the first reactor that discharged the product is filled with paraxylene, the chlorine gas continuously injected into the second reactor At the conversion rate of hexachloroparaxylene at which gas begins to be discharged as an unreacted product, the process of transferring the unreacted chlorine gas to the first reactor to initiate the initial reaction with paraxylene in the first reactor is repeated to produce non-reacting It may include a method of producing hexachloroparaxylene without discharging chlorine gas to the outside.

According to one aspect of the present invention, in the method of producing terephthaloyl chloride by reacting hexachloroparaxylene and terephthalic acid, paraxylene and chlorine gas are photoreacted in four or more temperature ranges depending on the melting point of the intermediate product. Preparing hexachloroparaxylene; And reacting the hexachloroparaxylene and terephthalic acid under a Lewis acid catalyst to produce terephthaloylchloride.

According to one aspect of the present invention, the method for producing hexachloroparaxylene may include a plurality of reactors connected in parallel.

According to one aspect of the present invention, the plurality of reactors are reactors in which a first reactor and a second reactor are connected in parallel, and chlorine gas is continuously introduced into the first reactor filled with para-xylene to react and produce hexachloro-para-xylene. At the conversion rate of hexachloroparaxylene, where hydrochloric acid gas, which is a side-reactant due to conversion, is discharged to the outside, and chlorine gas continuously introduced from the first reactor where the reaction was started begins to be discharged as an unreacted product, the first Unreacted chlorine gas that is continuously introduced into the reactor and does not participate in the reaction is transferred to the second reactor without being discharged to the outside to initiate an initial reaction with para-xylene filled in the second reactor, and the reaction in the first reactor is terminated. The chlorine gas continuously injected into the first reactor is connected to the second reactor to start continuous input into the second reactor, and while the first reactor that discharged the product is filled with paraxylene, the chlorine gas continuously injected into the second reactor At the conversion rate of hexachloroparaxylene at which gas begins to be discharged as an unreacted product, the process of transferring the unreacted chlorine gas to the first reactor to initiate the initial reaction with paraxylene in the first reactor is repeated to produce non-reacting It may be producing hexachloroparaxylene without discharging chlorine gas to the outside.

According to one aspect of the present invention, the prepared hexachloroparaxylene may further include a purification step.

According to one aspect of the present invention, the purification step may be purification using a distillation column.

According to one aspect of the present invention, the distillation column may include purifying hexachloroparaxylene at a bottom temperature of 100 to 300°C, a top temperature of 100 to 250°C, and a pressure of 1 to 20 torr. there is.

According to one aspect of the present invention, the Lewis acid catalyst may include any one or two or more selected from aluminum trichloride, zinc chloride, and ferric trichloride.

According to one aspect of the present invention, the prepared terephthaloyl chloride may further include a purification step.

According to one aspect of the present invention, the purification step may be purification using a distillation column.

According to one aspect of the present invention, the distillation column may purify hexachloroparaxylene at a controlled distillation temperature of 75 to 250°C and a pressure of 1 torr to 20 torr.

The present invention can provide hexachloroparaxylene with a low impurity content by providing hexachloroparaxylene through light irradiation instead of a radical initiator.

In addition, the present invention controls the reaction temperature during the photoreaction by dividing it into a plurality of sections and gradually increases the reaction temperature in each section, thereby maintaining relatively high chlorine gas solubility within an appropriate viscosity to produce high yield of hexachloroparahydrate. Xylene may be provided.

The present invention introduces a chlorine gas circulation system that circulates unreacted chlorine gas to the first and second reactors when producing hexachloroparaxylene, an intermediate raw material, to produce hexachloroparaxylene without emitting toxic chlorine gas to the outside. There is an advantage in producing xylene.

Figure 1 shows a schematic diagram of the manufacturing steps for producing terephthaloyl chloride.
Figure 2 shows a schematic diagram of the manufacturing steps of hexachloroparaxylene.

Hereinafter, the present invention will be described in more detail through specific examples or examples including the attached drawings. However, the following specific examples or examples are only a reference for explaining the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms.

Additionally, unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention pertains. The terminology used herein is merely to effectively describe particular embodiments and is not intended to limit the invention.

Additionally, as used in the specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to also include the plural forms, unless the context clearly dictates otherwise.

Additionally, when a part "includes" a certain component, this means that it may further include other components rather than excluding other components, unless specifically stated to the contrary.

Additionally, the chlorinated intermediate product described later in the present invention may be monochloroparaxylene, dichloroparaxylene, trichloroparaxylene, tetrachloroparaxylene, or pentachloroparaxylene.

Hexachloroparaxylene, the final product produced by the chlorination reaction of the present invention, is produced by irradiating chlorine gas with ultraviolet rays and producing a substitution reaction of chlorine radicals with the hydrogen of the methyl group of paraxylene.

However, as the concentration of hexachloroparaxylene increases through the photoreaction, the viscosity also increases, causing a problem in that the reaction rate decreases.

On the other hand, when reacting at a high reaction temperature, the viscosity is low, but the solubility of chlorine gas in liquid para-xylene becomes very low. As a result, the time to participate in the reaction is very short, which may cause problems in that it is discharged to the outside before reacting with paraxylene.

Accordingly, in order to solve the problem that occurs when the reaction temperature is raised as described above, the present invention increases the melting point of the product by the intermediate product produced as the degree of chlorination of para-xylene increases, and the melting point of the product increases. When an increasing amount of intermediate products are produced, the reaction temperature of the mixture containing the intermediate products is raised between the melting point start temperature and the melting point end temperature, and the reaction is carried out by dividing the reaction into 4 or more steps, preferably 10 or more steps. This was achieved by performing .

As the conversion rate of the intermediate product increases, when the product is recovered and the melting point is measured, the solubility of chlorine gas is increased by dividing the stages between the melting point start point at which melting begins and the melting point end point at complete melting as possible. The goal is to provide a new reaction method that adopts an environmentally friendly means of reacting by inducing chlorine gas to participate in the reaction as much as possible and substantially eliminating or minimizing the entire chlorine gas leaking to the outside.

Specifically, during the above reaction, chlorination products are generated as chlorination progresses to the methyl group of para-xylene. The chlorinated products have a higher melting point than para-xylene, and as chlorination progresses further in para-xylene, the melting point of the chlorinated products also increases. For example, the melting point of trichloroparaxylene is higher than monochloroparaxylene, and the melting point of pentachloroparaxylene is higher than trichloroparaxylene.

Therefore, the present invention recognizes that the melting point of various types of chlorinated intermediate products or mixtures of final products produced according to the conversion rate of para-xylene by chlorination of para-xylene increases, and that the reaction temperature increases as the melting point increases. By conducting a thermal reaction while continuously raising the temperature, a new, environmentally friendly method of producing hexachloroparaxylene that can be used in the reaction without external discharge of chlorine is provided.

The present invention divides the temperature section from low temperature to high temperature into at least 3-step section, 4-step section, 5-step section, 6-step section, 7-step section, 8-step section, 9-step section, or 10-step or more section. By reacting while raising the temperature , the reaction speed is fast by controlling the solubility of chlorine gas while maintaining the viscosity at a certain level, and chlorine can participate as much as possible in the reaction without external leakage, thereby achieving a high yield of over 95%.

In one embodiment according to the present invention, the reaction is initiated for 4 hours under conditions of increasing the reaction temperature from 13°C to 20°C, and as the conversion rate progresses, the reaction temperature is 4 hours at 47°C to 60°C, and 4 hours at 63°C to 67°C. React for 4 hours, 67℃ to 83℃ for 14 hours, 87℃ to 99℃ for 2 hours, and 106℃ to 113℃ for 2 hours to convert more than 95% of the product, preferably more than 98% of the product, and also chlorine. It can react without external leakage of gas.

In addition, the present invention combines the step of circulating unreacted chlorine gas from the first reactor to the second reactor, or from the second reactor to the first reactor, in addition to the multi-stage reaction temperature according to the melting point of the product to prevent external leakage of chlorine gas. Measures to prevent or minimize were adopted.

By means of the present invention, the present inventors have solved the problem of proceeding directly with the photoreaction by raising the temperature to a temperature at which all chlorinated intermediate products or final products can be melted, as in the prior art.

In other words, according to the present invention, it is not smooth to control the reaction due to the high temperature, and in particular, the solubility of the chlorine gas used in the reaction is lowered, which causes a problem in that the efficiency of the reaction is reduced, and it is also difficult to discharge unreacted chlorine to the outside. I learned that inevitable problems can be eliminated or minimized.

The present invention is a multi-stage reaction temperature means for reacting by gradually increasing the temperature from the para-xylene melting point according to the melting point of the chlorinated product and/or reacting with chlorine gas introduced from one reactor in the first and second reactors connected in parallel. The above purpose could be achieved by circulating the unreacted and remaining chlorine gas to another reactor to participate in the reaction.

In this reaction, by adopting the above-mentioned temperature range and the circulation reaction means of reaction chlorine gas, there is an advantage that para-xylene can maintain the reactivity of the chlorination reaction at a high level even when mixed gas of chlorine and hydrochloric acid produced as a reaction by-product is used. .

The circulation of the chlorine gas will be described in detail.

In the photoreaction for producing hexachloroparaxylene using paraxylene, as the reaction progresses, the reaction rate of chlorine gas gradually increases, resulting in additional chlorine substitution reaction. As the speed gradually decreases, a problem occurs in which the content of unreacted chlorine gas increases.

Accordingly, in the present invention, a plurality of reactors are connected in parallel, and unreacted chlorine gas discharged sequentially from the plurality of reactors is transferred to another reactor and circulated, and unreacted chlorine gas is transferred to another reactor without being discharged to the outside for reaction. A means of encouraging participation was adopted.

The plurality of reactors may be two or three or more, but this is not limited.

Hereinafter, a more detailed description will be given using a reactor in which two reactors are connected in parallel.

The present invention first starts the reaction by continuously introducing chlorine gas into a first reactor filled with para-xylene and discharging hydrochloric acid gas, a side-reactant resulting from the conversion of hexachloro-para-xylene, to the outside. At this time, the injected chlorine gas reacts quantitatively with paraxylene and is consumed. Subsequently, at the conversion rate of hexachloroparaxylene at which chlorine gas continuously introduced into the first reactor begins to be discharged as unreacted material, unreacted chlorine gas continuously introduced into the first reactor and does not participate in the reaction is discharged from the first reactor. At this point, the unreacted chlorine gas discharged is transferred to the second reactor without being discharged to the outside, and the initial reaction with paraxylene filled in the second reactor is initiated. The circulating chlorine gas is reacted by stopping the introduction of chlorine gas into the first reactor as soon as the reaction in the first reactor is completed, connecting the chlorine gas introduced into the first reactor to the second reactor, and continuously introducing it into the second reactor. to participate in

Then, in the first reactor that discharged the product, the starting material para-xylene is filled again, and at the conversion rate of hexachloro-para-xylene at which chlorine gas continuously introduced into the second reactor begins to be discharged as unreacted material, the unreacted By repeating the process of circulating chlorine gas to the first reactor to initiate the initial reaction with para-xylene in the first reactor, hexachloro-para-xylene is produced without discharging unreacted chlorine gas to the outside.

The method for producing hexachloroparaxylene will be described in more detail step by step with reference to FIG. 2 below.

According to one aspect of the present invention, the hexachloroparaxylene production step is

S1) filling the first reactor 100 and the second reactor 200 with para-xylene;

S2) Chlorine gas is continuously introduced into the first reactor (100), the introduced chlorine gas reacts 100% with para-xylene, and hydrochloric acid gas, a by-product discharged from the reaction, flows through the first transfer pipe (110). recovering hydrochloric acid by transferring it to an incinerator (600);

S3) when the reaction of chlorine gas in the first reactor 100 decreases to 100% or less and unreacted chlorine gas is generated, blocking the first discharge pipe 110;

S4) After blocking the first discharge transfer pipe 110, the unreacted chlorine gas and residual hydrochloric acid gas in the first reactor 100 are transferred to the second reactor 200 through the first cross transfer pipe 120. A step of initially reacting in the second reactor 200 and producing hexachloroparaxylene simultaneously in the first reactor 100 and the second reactor 200;

S5) transferring hydrochloric acid gas generated as a by-product in the second reactor 200 to the incinerator 600 through the second discharge pipe 210 at the top of the second reactor 200;

S6) When the reaction in the first reactor 100 is completed, blocking the first cross transfer pipe 120 and changing the chlorine gas introduced into the first reactor 100 into the second reactor 200;

S7) discharging hexachloroparaxylene as a product into the first reactor 100 and introducing new paraxylene;

S8) When the chlorine gas reaction in the second reactor 200 decreases to 100% or less and unreacted chlorine gas is generated, the second discharge pipe 210 is blocked and the unreacted chlorine gas and Injecting residual hydrochloric acid into the first reactor 100 through the second cross transfer pipe 220 to simultaneously proceed with the hexachloroparaxylene production reaction in the second reactor 200 and the first reactor 100;

S9) After the reaction in the second reactor 200 is completed, the chlorine gas introduced into the second reactor 200 is introduced into the first reactor 100 to react, and the first discharge pipe 110 is opened. transporting hydrochloric acid, a by-product, to an incinerator (600) to recover hydrochloric acid; and

S10) discharging hexachloroparaxylene into the second reactor 200 and adding new paraxylene; repeating steps S2 to S10 to continuously produce hexachloroparaxylene It may include steps.

In the hexachloroparaxylene production step, chlorine gas and paraxylene are produced into hexachloroparaxylene through photoreaction. The chlorine gas is decomposed into chlorine radicals due to the photo reaction, and the chlorine radicals are replaced with the hydrogen of the methyl group of para-xylene to produce hexachloro-para-xylene, and hydrochloric acid is discharged as a by-product.

Through the method for producing hexachloroparaxylene, all chlorine gas can be consumed in the reaction, thereby preventing chlorine gas, which is fatal to the human body or the environment, from being released to the outside.

In addition, in the method for producing hexachloroparaxylene, there is an advantage that reactivity can be maintained at a high level even when the mixed gas of chlorine and hydrochloric acid is used when reacting within the plurality of temperature ranges.

Additionally, according to one aspect of the present invention, the photoreaction may include an ultraviolet light amount range of less than 2000 LUX, specifically 100 to 1,800 LUX, and specifically 100 to 1,500 LUX.

Conventionally, the amount of light input to the photoreaction was a high-energy light amount in the range of 2,000 LUX to 50,000 LUX ultraviolet rays, but there were disadvantages in that side reactions may occur in this light amount range and the yield of hexachloroparaxylene was low.

Accordingly, the present inventors found that hexachloroparaxylene can be produced even by controlling the irradiated light amount range to 100 to 1,500 LUX of ultraviolet rays, and that side reactions are low and yield is high when produced in the above light amount range.

In addition, when reacting in the above light amount range, the reaction heat generated according to the reaction is low, which is very good for temperature control and has the advantage of controlling the reaction rate at the same time.

In addition, the irradiation area for the light reaction is not limited as long as the reaction proceeds smoothly, but is specifically 5 to 30 cm ² per Kg of paraxylene, specifically 10 to 20 cm ² , specifically 10 to 15 cm 2 per kg of paraxylene. It can be ^cm2 .

Previously, a mercury lamp was used as a light source for the photo reaction. However, the short-wavelength light of the low-pressure mercury lamp can cause other photochemical side reactions and lower the purity of the product, while the long-wavelength light of the high-pressure mercury lamp causes a chlorine radical reaction. It may not be enough to wake you up, so more energy may be consumed. In addition, when using the mercury lamp, more heat is generated, and problems such as the need to introduce an additional cooling device to reduce the heat may occur.

Accordingly, the present invention overcomes the disadvantages of the mercury lamp by using an LED lamp. By using the LED lamp, the wavelength range appropriate for the reaction can be controlled, thereby reducing photochemical side reactions, and it has the advantage of not requiring an additional cooling device because it does not generate heat compared to a mercury lamp even when used for a long period of time. In addition, the LED lamp has low power consumption and has the advantage of high energy efficiency.

In particular, in the case of a mixed gas of chlorine gas and hydrochloric acid gas introduced into the reactor through the first cross transfer pipe or the second cross transfer pipe, the probability of side reactions occurring is higher than that of single chlorine gas at high light levels, and this causes the problem of reduced reactivity. It can happen.

Accordingly, in the present invention, by irradiating the amount of light below 2,000 LUX, the side reaction can be reduced and high yield of hexachloroparaxylene can be obtained.

In addition, by satisfying the light amount range and the temperature range of the plurality of temperature sections at the same time, side reactions are very low and at the same time, the discharge of hydrochloric acid gas, a by-product, is smooth, so that a very high yield of hexachloroparaxylene can be obtained.

The discharged hydrochloric acid gas moves to the incinerator, all unreacted chlorine gas is discharged from the incinerator, and the hydrochloric acid gas enters the hydrochloric acid production facility to produce a 35% hydrochloric acid solution.

Specifically, the hydrochloric acid gas generated from the incinerator is dissolved in water through a scrubbing system within the hydrochloric acid production facility and produced as hydrochloric acid.

The prepared 35% hydrochloric acid solution is transferred to a hydrochloric acid tank and stored.

According to one aspect of the present invention, terephthaloyl chloride can be produced by reacting the prepared hexachloroparaxylene with terephthalic acid.

As one embodiment, the step of producing terephthaloyl chloride includes producing hexachloroparaxylene from paraxylene; Purifying the prepared hexachloroparaxylene; It may include the step of reacting the purified para-xylene and terephthalic acid under an acid catalyst to produce terephthalic monochloride.

In addition, as one embodiment, the step of producing terephthaloyl chloride includes producing hexachloroparaxylene from paraxylene; Purifying the prepared hexachloroparaxylene; Preparing terephthalic monochloride by reacting the purified para-xylene and terephthalic acid under a Lewis acid catalyst; and purifying the prepared terephthaloyl chloride.

First, the hexachloroparaxylene purification step may include a recrystallization method, a rectification method, a distillation method, etc., and the distillation method may include a vacuum distillation method or a molecular distillation method.

In the purification step, the distillation method can be distilled using a distillation tower, and the distillation tower is not limited to this if it is a device that generally distills compounds.

The distillation column can purify hexachloroxylene under conditions where the bottom temperature of the distillation temperature is 100 to 300°C, the top temperature is 100 to 250°C, and the pressure is 1 to 20 torr, but is not limited thereto.

Additionally, the catalyst used in the step of producing terephthaloyl chloride by reacting the purified hexachloroxylene with terephthalic acid in the presence of an acid catalyst may be a Lewis acid catalyst.

The Lewis acid catalyst may include any one or two or more selected from aluminum trichloride, zinc chloride, and ferric trichloride, but is not limited thereto as long as it is a catalyst commonly used in the above synthesis.

The terephthaloyl chloride synthesis may be performed by adding 30 to 300 parts by weight of terephthalic acid, preferably 40 to 200 parts by weight, and more preferably 45 to 130 parts by weight, based on 100 parts by weight of hexachloroparaxylene. It is not limited.

In addition, based on 100 parts by weight of hexechloroparaxylene, the acid catalyst may include 0.001 to 10 parts by weight, preferably 0.003 to 1 part by weight, and more preferably 0.005 to 0.01 parts by weight, but is not limited thereto. no.

In addition, according to one aspect of the present invention, the prepared terephthaloyl chloride may further include a purification step, and the terephthaloyl chloride purification step may include a recrystallization method, a rectification method, a distillation method, etc. The distillation method may include a vacuum distillation method or a molecular distillation method.

In the terephthaloyl chloride purification step, the distillation method can be distilled using a distillation tower, and the distillation tower is not limited to this if it is a device that generally distills compounds.

The distillation column can purify terephthaloyl chloride at a controlled distillation temperature of 75 to 250°C and a pressure of 1 torr to 20 torr, but is not limited thereto.

The present invention will be described in more detail below based on examples and comparative examples. However, the following Examples and Comparative Examples are only one example to explain the present invention in more detail, and the present invention is not limited by the following Examples and Comparative Examples.

[Example 1]

1) Hexachloro-p-xylene manufacturing steps

After injecting 100 parts by weight of para-xylene from the para-xylene supply unit 300 into the first reactor 100 and the second reactor 200, nitrogen is supplied from the nitrogen gas supply unit 500 to the first reactor. (100) After removing the air inside by injecting it inside, chlorine gas was injected from the chlorine gas supply unit (400) into the first reactor (100) and photoreacted to produce hexachloroparaxylene.

The injected chlorine gas was injected at a rate of 30 parts by weight per hour for 100 parts by weight of paraxylene.

In the photoreaction, the reaction temperature is as the reaction progresses in the first reactor 100, intermediate products are generated according to the conversion rate in Table 1 below, and the melting point of the intermediate product mixture increases due to the production of the intermediate product, and the temperature as shown in Table 2 The reaction was carried out under multi-step temperature increasing conditions with time and temperature. During the reaction, stirring was performed at 300 rpm, and the light reaction was irradiated with ultraviolet rays of 1,000 LUX on a light area of 15 cm ² per 1 kg of raw material.

In addition, the external chlorine gas introduced into the first reactor participated in the reaction quantitatively at the beginning of the reaction and was consumed, and at this time, hydrochloric acid, a by-product, was discharged to the incinerator 600 through the first discharge pipe 110. When the yield of hexachloroparaxylene reached 0.1%, unreacted chlorine gas began to be discharged to the outside, so at this time, unreacted chlorine gas was circulated to the second reactor to produce the same amount of heat as in the first reactor. The chlorination reaction was initiated under these conditions.

In the first reactor, the reaction was performed under the conditions of Table 1 and Table 2, and the reaction was terminated after 32 hours. The chlorine gas introduction pipe of the first reactor was connected to the chlorine gas introduction pipe of the second reactor, and chlorine gas was supplied to the second reactor. It was put in. The reaction was performed under the conditions of the conversion rate, reaction temperature, and time in the second reactor as shown in Tables 3 and 4.

At the point where unreacted chlorine gas was generated in the second reactor at a hexaparaxylene yield of 0.1%, the chlorine gas was transferred to the first reactor and the chlorination reaction was initiated in the first reactor.

[Table 1]

[Table 2]

2) Hexachloroparaxylene purification step

Hexachloroparaxylene produced in the first reactor 100 and the second reactor 200 was transferred to the bottom of the first distillation tower. In order to purify the hexachloroparaxylene, the first distillation column is purified at a total distillation column pressure of 5 torr, a bottom temperature of 160°C, a tower temperature of 150°C, and a stirring speed of 300 rpm to purify hexachloroparaxylene to high purity. After fractionation of xylene and the hexachloroparaxylene residue, the purified hexachloroparaxylene was transferred to a first storage tank and stored.

3) Terephthaloyl chloride reaction step

In the hexachloroparaxylene purification step, high-purity hexachloroparaxylene stored in the first storage tank is transferred to a third reactor, and terephthalic acid and iron chloride (FeCl ₃ ) catalyst are added to the third reactor. Terephthaloyl chloride was prepared by reacting for 5 hours.

The reaction was performed by mixing 100 parts by weight of high-purity hexachloro-p-xylene, 100 parts by weight of terephthalic acid, and 0.005 parts by weight of FeCl ₃ , and the reaction conditions were maintained at a temperature of 120°C and an atmospheric pressure.

4) Terephthaloyl chloride purification step

The terephthaloyl chloride produced in the 3) terephthaloyl chloride reaction step was transferred to the second distillation column and subjected to primary purification. The purification conditions of the second distillation tower were carried out under the conditions of a total distillation tower pressure of 5 torr, a bottom temperature of 160°C, a tower temperature of 130°C , and a stirring speed of 300 rpm. The highly purified terephthaloyl chloride was transferred to a second storage tank and stored.

As described above, the present invention has been described with specific details, limited embodiments, and drawings, but these are provided only to facilitate a more general understanding of the present invention, and the present invention is not limited to the above embodiments, and the present invention Anyone skilled in the art can make various modifications and variations from this description.

Accordingly, the spirit of the present invention should not be limited to the described embodiments, and the scope of the patent claims described below as well as all modifications that are equivalent or equivalent to the scope of this patent claim shall fall within the scope of the spirit of the present invention. .

100: first reactor
110: First discharge transfer pipe
120: First cross transfer pipe
200: Second reactor
210: Second discharge transfer pipe
220: Second cross transfer pipe
300: Paraxylene supply department
400: Chlorine gas supply unit
500: Inert gas supply unit
600: Incinerator
700: Hydrochloric acid manufacturing equipment

Claims (13)

A method of producing hexachloroparaxylene by photoreacting paraxylene and chlorine gas. The reaction is performed in a plurality of reactors connected in parallel, and the photoreaction in each reactor is performed according to the conversion rate of hexachloroparaxylene. The reaction is carried out in a plurality of temperature ranges of 4 or more stages according to the increase in the melting point of the intermediate product produced.
A method for producing paraxylene, wherein unreacted chlorine gas released from one of the plurality of reactors is circulated to another reactor to participate in the reaction.
delete According to paragraph 1,
The plurality of reactors are reactors in which a first reactor and a second reactor are connected in parallel, and chlorine gas is continuously injected into the first reactor filled with para-xylene to react, and hydrochloric acid gas, which is a side reactant due to the conversion of hexachloro-para-xylene, is reacted. The reaction begins by discharging to the outside, and at the conversion rate of hexachloroparaxylene at which chlorine gas, which is continuously introduced from the first reactor where the reaction is initiated, begins to be discharged as unreacted material, it is continuously introduced into the first reactor and participates in the reaction. Unreacted chlorine gas is not discharged to the outside but is transferred to the second reactor to initiate an initial reaction with the para-xylene filled in the second reactor. After the reaction in the first reactor is completed, chlorine is continuously introduced into the first reactor. Gas is connected to the second reactor and continuous injection into the second reactor begins. In the state where para-xylene is filled into the first reactor that discharged the product, chlorine gas continuously introduced into the second reactor begins to be discharged as unreacted material. At the conversion rate of hexachloroparaxylene, the process of transferring the unreacted chlorine gas to the first reactor to initiate the initial reaction with paraxylene in the first reactor is repeated, without discharging the unreacted chlorine gas to the outside. Method for producing hexachloroparaxylene.
A method of producing terephthaloyl chloride by reacting hexachloroparaxylene and terephthalic acid,
The reaction is carried out in a plurality of reactors connected in parallel,
Producing hexachloroparaxylene by photoreacting paraxylene and chlorine gas in 4 or more temperature ranges depending on the melting point of the intermediate product; and
It includes the step of reacting the hexachloroparaxylene and terephthalic acid under a Lewis acid catalyst to produce terephthaloylchloride,
A method for producing terephthaloyl chloride, wherein unreacted chlorine gas released from one of the plurality of reactors is circulated to another reactor to participate in the reaction.
delete According to paragraph 4,
The plurality of reactors are reactors in which a first reactor and a second reactor are connected in parallel, and chlorine gas is continuously injected into the first reactor filled with para-xylene to react, and hydrochloric acid gas, which is a side reactant due to the conversion of hexachloro-para-xylene, is reacted. The reaction begins by discharging to the outside, and at the conversion rate of hexachloroparaxylene at which chlorine gas, which is continuously introduced from the first reactor where the reaction is initiated, begins to be discharged as unreacted material, it is continuously introduced into the first reactor and participates in the reaction. Unreacted chlorine gas is not discharged to the outside but is transferred to the second reactor to initiate an initial reaction with the para-xylene filled in the second reactor. After the reaction in the first reactor is completed, chlorine is continuously introduced into the first reactor. Gas is connected to the second reactor and continuous injection into the second reactor begins. In the state where para-xylene is filled into the first reactor that discharged the product, chlorine gas continuously introduced into the second reactor begins to be discharged as unreacted material. At the conversion rate of hexachloroparaxylene, the process of transferring the unreacted chlorine gas to the first reactor to initiate the initial reaction with paraxylene in the first reactor is repeated, without discharging the unreacted chlorine gas to the outside. A method for producing terephthaloyl chloride to produce hexachloroparaxylene.
According to clause 4,
A method for producing terephthaloyl chloride, wherein the prepared hexachloroparaxylene further includes a purification step.
According to clause 7,
The purification step is a method of producing terephthaloyl chloride, wherein the purification step is purification using a distillation column.
According to clause 8,
The distillation tower has a bottom temperature of 100 to 300 ℃, a tower temperature of 100 to 250 ℃, and a pressure of 1 to 20 torr to purify hexachloroparaxylene. A method of producing terephthaloyl chloride.
According to clause 4,
A method for producing terephthaloyl chloride, wherein the Lewis acid catalyst is any one or two or more selected from aluminum trichloride, zinc chloride, and ferric trichloride.
According to clause 4,
A method for producing terephthaloyl chloride, wherein the prepared terephthaloyl chloride further includes a purification step.
According to clause 11,
The purification step is a method of producing terephthaloyl chloride, wherein the purification step is purification using a distillation column.
According to clause 12,
The method of producing terephthaloyl chloride, wherein the distillation tower purifies hexachloroparaxylene at a controlled distillation temperature of 75 to 250°C and a pressure of 1 torr to 20 torr.