JP2002336687A - Method for producing compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an industrially very economical production method in which a drier is made unnecessary or energy used for drying can be diminished as a method for producing a compound in which a slurry is formed under pressure and/or under heating. SOLUTION: The method for producing a compound has (A) a reaction step in which reaction is carried out in a reactor under a higher pressure than atmospheric pressure and a temperature equal to or higher than the boiling point of a used reaction medium under atmospheric pressure to form the compound, (B) a separation step in which a specific quantity or more of the reaction medium is separated from the resulting slurry containing the compound and the reaction medium in a separator under a higher pressure than atmospheric pressure and a temperature equal to or higher than the boiling point of the reaction medium under atmospheric pressure to obtain a cake in which the weight ratio of a liquid sticking to the cake to the solid component is <=50% and (C) a drying step in which the obtained cake is transferred to a compound recovery zone kept under a lower pressure than the pressure in the separator and a lower temperature than the temperature in the separator and the liquid sticking to the cake is evaporated by internal energy released by the transfer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a compound. More specifically, the present invention relates to a method for producing a compound obtained by reacting under pressure and heat, comprising a step of removing adhering substances such as a reaction medium and / or a washing solution from the compound using internal energy. .

[0002]

BACKGROUND OF THE INVENTION The case where the desired solid particle product is obtained as a slurry which is a mixture with a reaction mother liquor is found in chemical processes. Generally, a solid particle product is obtained by subjecting the slurry to a unit operation of separation and drying. There have been many attempts to improve the above unit operation and process. For example, with respect to the drying operation, Japanese Patent Application Laid-Open No. 52-59177 discloses an example in which a compressed air transfer dryer is used, and drying is performed by external heating using hot gas or hot air. JP-B-58-11418 and JP-A-55-164650 disclose examples in which a slurry liquid is evaporated in a heating tube to obtain a solid and a gas. However, in these methods, it is necessary to use energy corresponding to drying in order to dry the cake by newly applying heat on the premise that the drying operation is performed independently.

On the other hand, it is common practice to carry out crystallization by lowering the temperature while maintaining a slurry state as a pretreatment for solid-liquid separation. For example, in British Patent No. 1152575,
An example is shown in which the solvent is evaporated to cause cooling and to precipitate terephthalic acid. However, evaporation itself only slightly increases the slurry concentration, and has no effect on the process other than lowering the temperature. Also, JP-A-11-335
No. 32 discloses an example in which terephthalic acid is reslurried and flushed with a cleaning liquid. Since it is difficult to extract the powder from the pressurized state, a method of extracting the powder by reslurrying is generally known, but attention has not been paid to the negative part where energy is lost. Thus, the process of lowering the temperature of the slurry, dissipating energy and reheating by drying, as shown in the two examples above,
It is hard to say that energy is being used effectively.

Japanese Patent Application Laid-Open No. 1-299618, US Pat. No. 5,698,734, and WO 91/09661 exemplify cake separation under a pressurized state. However, retention of thermal energy of a slurry before separation is effective for cake drying. Nothing is said about it. In addition, Japanese Patent Translation
No. 6461 describes an example in which a slurry of terephthalic acid and water is separated under pressure and the water remaining in the cake is flash evaporated. However, since the latent heat of evaporation of water is high, only a part of the liquid adhering to the cake can be evaporated, and it is necessary to go through a normal drying step to remove the compound.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to utilize the internal energy of the slurry after the reaction to reduce the energy consumption in the drying step, and it is particularly preferable to dry the cake only from the internal energy of the slurry. In this case, the energy used is greatly reduced, and the separation / drying step is integrated to construct a simple process.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, they have obtained a reaction under pressure and heating by employing a specific manufacturing process. The inventors have found that the internal energy of the reactants has the ability to evaporate most of the cake adhering liquid, and have completed the present invention.

That is, the gist of the present invention resides in a method for producing a compound having at least the following steps. (A) a reaction step of performing a reaction in a reactor at a pressure higher than the atmospheric pressure and at a temperature equal to or higher than the boiling point of the reaction medium at the atmospheric pressure to produce a compound;
At a pressure higher than the atmospheric pressure and a temperature higher than the boiling point of the reaction medium at the atmospheric pressure, a certain amount or more of the reaction medium is separated from the slurry containing the compound and the reaction medium, and the weight ratio of the cake adhering liquid to the solid content is 50% or less. A separation step of obtaining a cake, and (C) transferring the obtained cake to a compound recovery zone at a pressure lower than the pressure in the separation device and lower than the temperature in the separation device, and the internal energy released by the movement moves the cake. A drying step for evaporating the adhering liquid.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. FIG. 1 is a conceptual diagram for explaining a specific method of the present invention. Raw materials and a reaction medium are supplied to the reactor 1 from a line 11. The reaction is carried out under certain conditions in the reactor. The reaction product after the reaction is one liquid phase, two gas-liquid phases, two solid-liquid phases,
A gas-liquid-solid three-phase may be used, and particularly a solid-liquid two-phase and a gas-liquid-solid three-phase are called a slurry. In the production method of the present invention, in order to perform solid-liquid separation in the separation step, it is necessary that the slurry be formed at least before being transferred to the separation device. The target compound is obtained as a solid, preferably as a crystal, and a slurry containing at least the solid compound and the reaction medium is obtained. Note that the target compound may be partially dissolved in the reaction medium.

The reactants are transferred via line 12 to intermediate treatment tank 2 as necessary, where crystallization, dissolution, and other intermediate treatments are performed as necessary. The reactant having undergone the intermediate treatment is transferred to the separation device 3 via the line 13. If no intermediate treatment of the reactants is performed, the reactants are transferred directly from the reactor 1 to the separation device.

In the separation device 3, the solid and the liquid in the slurry are separated, and the weight ratio of the cake adhering liquid to the solid content is 50% or less, preferably 30% or less, more preferably 20% or less, particularly preferably 15% or less. % Of the cake (hereinafter, in this specification, the weight ratio (W1 / W) of the cake adhering liquid (W1) to the solid content (W2).
2) is referred to as the liquid content or content of the cake adhering liquid). In the separation device, the cake is washed with a washing liquid as needed. The cake produced in the separation device 3 is transferred to the powder tank 6 (compound recovery zone) through the chamber 4 and the valve 5, and the target compound is obtained as a solid.

Next, the respective steps of the reaction step (A), the separation step (B), the drying step (C), and the intermediate treatment step (D) which is added if necessary, in the production method of the present invention will be described.

(A) Reaction Step In the production method of the present invention, the reaction for producing a compound is as follows:
The reaction is carried out at a pressure higher than the atmospheric pressure and at a temperature equal to or higher than the boiling point of the reaction medium at the atmospheric pressure. Raw materials are supplied to the reactor 1 from a line 11. The line 11 may be singular or plural according to the feed condition. Raw materials are gas, liquid,
It may be either solid or slurry, and may be a single phase or a mixed phase. Further, the composition may be a pure substance or a mixture, but usually a reaction medium, a catalyst and additives as needed are added to the reaction substrate. Their composition is arbitrarily determined according to the type of reaction. The temperature is also arbitrarily determined, but is usually within a range where the reaction substrate and the reaction medium are not decomposed. Further, the phase state of the raw material may be intentionally changed according to the temperature. For example, there is an example in which the temperature is raised to make the slurry into a completely dissolved phase or the liquid phase to be a liquid-gas mixed phase.

The reaction forms used in the present invention include oxidation reaction, reduction reaction, substitution reaction, addition reaction, elimination reaction and the like.
Either may be used. Further, any of an exothermic reaction and an endothermic reaction may be used, but an exothermic reaction is preferable from the viewpoint of effectively utilizing internal energy. Further, the compound produced in the reaction vessel may be a liquid, but is preferably a solid,
More preferably, it is obtained as a crystal. The reaction may be carried out batchwise or continuously.

The reaction medium used in the present invention is a liquid or gas-liquid two-phase during the reaction step, and does not cause a chemical change in the reaction substrate or the target compound after the reaction. The latent heat of vaporization of the reaction medium at atmospheric pressure (hereinafter, the latent heat of vaporization is defined as atmospheric latent heat in the present invention) is 300 kcal / kg.
The following is preferable, 200 kcal / kg or less is more preferable, and 150 kcal / kg or less is particularly preferable. Although the lower limit of the latent heat of evaporation is not particularly defined, it is usually 50 kPa.
cal / kg or more, preferably 70 kcal / k
g or more.

The boiling point of the reaction medium at atmospheric pressure is preferably 40 ° C. or more and 200 ° C. or less, more preferably 5 ° C. or less.
0 ° C to 180 ° C, particularly preferably 60 ° C to 15 ° C
0 ° C. or less. When the boiling point of the reaction medium at atmospheric pressure is significantly lower than the above range, the handling and recovery of the reaction medium in each step tends to be difficult. When the compound is moved, the residual amount of the reaction medium tends to increase.

In the reactor 1, the raw material is supplied, and the target reaction substrate is chemically changed to 30% or more, preferably 50% or more, more preferably 70% or more, for example, 80% or more. The reaction mixture can be in various cases of liquid 1 phase, gas / liquid 2 phase, gas / liquid / solid 3 phase. The reaction conditions are determined in consideration of various factors such as the reaction rate and side reactions, solubility in the reaction medium, and the like, and the temperature is usually 50 ° C or higher and 350 ° C or lower, preferably 100 ° C or higher and 300 ° C or lower, more preferably 130 ° C or lower. ° C
The reaction is carried out at a temperature of not less than 250 ° C., particularly preferably not less than 150 ° C. and not more than 230 ° C., and not less than the boiling point at the atmospheric pressure of the reaction medium. The pressure exceeds atmospheric pressure and is 20MPa
Or less, preferably 0.2 MPa or more and 10 MPa or less, more preferably 0.5 MPa or more and 5 MPa or less, particularly preferably 1 MPa or more and 3 MPa.
It is implemented in the following range. If the reaction temperature and pressure are significantly lower than the above ranges, the internal energy of the cake obtained during the production process of the present invention is small, and the evaporation of the cake adhering liquid when transferring the cake to the compound recovery zone is not sufficient. . On the other hand, when the reaction temperature and pressure are significantly higher than the above ranges, a double reaction is likely to occur or the compound is easily decomposed, and the yield tends to decrease.

In the production method of the present invention, a catalyst may be used during the reaction step, and the catalyst may be a heterogeneous catalyst or a homogeneous catalyst. The temperature of the reactor is controlled by heating or removing heat. This depends on the temperature of the liquid supply and the type of reaction such as endothermic and exothermic. Heating is performed by a jacket or a coil, and heat removal can be further performed by evaporation.

In the reaction step, the reaction conditions may change on the way (including the case where there are a plurality of reactors). In such a case, the reaction conditions of the reaction step of the present invention are regulated (higher than atmospheric pressure). Pressure and temperature above the boiling point of the reaction medium at atmospheric pressure) refers to the reaction conditions closest in time to the separation step. Therefore, in the production method of the present invention, in the reaction step, the reaction is performed at a pressure lower than the atmospheric pressure or a temperature lower than the boiling point at the atmospheric pressure of the reaction medium, and after the reaction is completed, pressure and / or heating is performed to reach the separation device. A distinction is made between production processes in which a pressure above atmospheric pressure and a temperature above the boiling point of the reaction medium at atmospheric pressure is reached. In the process from the reactor to the separation device through the intermediate treatment tank used as needed, if the conditions for maintaining the pressure at or above atmospheric pressure and the temperature at or above the boiling point of the reaction medium are satisfied, dilution or heating may be performed. Additional unit operations such as may be entered.

(D) Intermediate treatment step The intermediate treatment step is not essential, and a plurality of intermediate treatment tanks can be provided. The intermediate treatment step includes, for example, cooling, heating, increasing pressure, decreasing pressure, concentrating, diluting, precipitating, adding, and the like. Typically, crystallization or dissolution is performed. For example, crystallization is performed to increase the recovery of the compound, and dissolution is performed to increase the purity of the compound.
These intermediate treatment steps are appropriately selected depending on the type of the target compound, product specifications, and the like.

When the reaction product obtained in the reaction step does not contain a solid such as a liquid 1 phase or a gas-liquid 2 phase such as a supersaturated state, the target compound is solidified before the separation step. It is essential to carry out the crystallization in the intermediate treatment step. The intermediate treatment step does not need to use a container such as an intermediate treatment tank, and may be performed in a line from the reaction step to the separation step.

When crystallization is performed as a preferred example of the operation in the intermediate treatment step, the number of crystallization stages is four or less, more preferably two or less, and particularly preferably one. Line 1
2. At any point of the intermediate processing tank 2 and the line 13, the reactant maintains a temperature higher than the boiling point of the reaction medium at the atmospheric pressure and a pressure higher than the atmospheric pressure.
The pressure range is preferably above atmospheric pressure and 20 MPa or less, more preferably 0.2 MPa or more and 10 MPa or less, particularly preferably
It is 0.3 MPa or more and 5 MPa or less. The temperature range is usually 50 ° C
The temperature is not less than 350 ° C and preferably not less than 100 ° C and not more than 300 ° C, more preferably not less than 130 ° C and not more than 250 ° C.

The boiling point of the reaction medium at atmospheric pressure (Bp1)
And the difference (T) between the temperature (TD) of the reactant in the intermediate treatment step 2
D-Bp1) is preferably in the range of 5 ° C to 200 ° C, more preferably in the range of 10 ° C to 150 ° C,
Particularly preferably, the temperature is in the range of 15 ° C to 100 ° C.
By maintaining the above temperature difference, at least a part of the thermal energy of the reactant extracted from the line 12 can be left in the reactant in the line 13. In addition,
As described above, the reactant may be a liquid 1 phase, a gas-liquid 2 phase, a solid-liquid 2 phase, and a gas-liquid solid 3 phase. As will be appreciated, during the manufacturing process of the present invention, the reactants are usually slurries at the time they move through line 13.

(B) Separation Step The slurry-like reactant is transferred from the intermediate treatment tank 2 via the line 13 or from the reactor 1 to the separation apparatus 3 via another line (not shown). . The mechanism of the separation device 3 is not particularly limited, and is generally known such as a centrifugal separator, a horizontal belt filter, a rotary vacuum filter and the like as shown in JP-A-7-507291, and as shown in JP-A-6-502653. Filter cells can also be used. In particular, when a centrifuge is used, a screen bowl decanter or a solid bowl decanter can be selected.

The pressure and temperature of the separator 3 are adjusted so that the thermal energy of the slurry entering the separator 3 from the line 13 is not completely dissipated. If the pressure of the separation device 3 is low, the slurry is flushed and the temperature is lowered. Therefore, the pressure of the separation device 3 is higher than the atmospheric pressure,
If desired, the pressure may be higher than the pressure in the reactor 1 or the intermediate processing tank 2. The slurry transferred to the separator is subjected to solid-liquid separation in the separator, and the content of the reaction medium in the slurry with respect to the solid content is reduced to 50% or less, preferably 30% or less, to obtain a cake. In the production method of the present invention, the target compound forms a main component of the cake as a solid, to which a reaction medium or a washing liquid is used to wash the cake as described below (in the present specification, the washing liquid is present in the cake. The reaction medium and the washing liquid are collectively referred to as a cake adhering liquid) in the range of 50% or less, preferably 30% or less, based on the solid content.

The temperature (TB2) of the cake immediately before discharge obtained in the separator 3 is preferably higher than the boiling point (Bp2) at atmospheric pressure of the cake adhering liquid immediately before discharge from the separator 3. For example, when transferring the slurry from the line 13 to the separation step 3 having a high pressure, the slurry can be transferred by increasing the pressure by a pump or the like before the separation step 3 is started. The pressure range of the separation step 3 is preferably from 0.11 MPa to 22 MPa,
More preferably, it is 0.21 MPa or more and 12 MPa or less, particularly preferably 0.31 MPa or more and 7 MPa or less. The range of the cake temperature immediately before discharge is 50 ° C or higher and 350 ° C or lower, preferably 100 ° C or higher and 300 ° C or lower.
° C or lower, more preferably 130 ° C or higher and 250 ° C or lower.
The difference between the boiling point of the cake adhering liquid immediately before being discharged from the separation step 3 at atmospheric pressure and the temperature difference (TB2-Bp2) of the cake discharged from the separation step 3 is preferably 5 ° C. or more and 200 ° C.
C. or lower, more preferably 10 to 150.degree. C., particularly preferably 15 to 100.degree.

It is also possible to add a washing function to the separation device 3. The type of the washing solution is not particularly limited, and may be a component completely different from the reaction medium or, conversely, the same component. Further, the presence or absence of reslurry in cleaning is not particularly limited. Again, the amount and temperature of the cleaning liquid is controlled so that the thermal energy of the separation cake is not dissipated. When a low-temperature cleaning solution is used, the amount of the cleaning solution is reduced to suppress the influence. If the temperature of the cleaning liquid can be increased to suppress heat removal from the cake, the amount of the cleaning liquid can be increased. Therefore, the specific temperature of the cleaning liquid is higher than the boiling point of the cleaning liquid at atmospheric pressure, and TB1 + 10
0 ° C. or less (where TB1 is the temperature of the unwashed cake, which is generally approximately equal to the temperature in the separator before washing), preferably in the range of TB1 or more and TB1 + 80 ° C. or less, more preferably TB1 + 5 ° C. or more TB1 + 60 ° C
The range is as follows.

The specific amount of the washing liquid is preferably 0.03 or more and 5.0 or less, more preferably 0.05 or more and 4.0 or less, particularly preferably 0.05 to 4.0 in terms of weight ratio to the solid content in the cake. It is 0.1 or more and 3.0 or less. In addition, in order to avoid bumping of the cleaning liquid, the pressure in the separation device for introducing the cleaning liquid is set to be higher than the vapor pressure of the cleaning liquid. Preferably, the pressure in the separator is higher than the vapor pressure of the slurry supplied to the separator by 0.01 to 2.0 MPa, more preferably 0.01 to 1.0 MPa, and particularly preferably 0.02 to 2.0 MPa.
０．５0.5 MPa higher range.

The type of the washing liquid is not particularly limited, except that it is present as a liquid under the pressure and temperature conditions in the separation device. Further, the composition of the cleaning liquid may be completely different from that of the reaction medium, and there is no limitation on the latent heat of vaporization of the reaction medium. The latent heat of evaporation of the washing liquid is preferably 300 kcal / kg or less, more preferably 200 kcal / kg or less, and particularly preferably 150 kcal / kg or less. The lower limit of the latent heat of vaporization is not particularly limited, and it is better to be as small as possible as long as it can be used as a cleaning liquid.
/ Kg or more, preferably 70 kcal / kg or more.

The boiling point of the cleaning solution at atmospheric pressure is preferably 40 ° C. or more and 200 ° C. or less, more preferably 5 ° C. or less.
0 ° C to 180 ° C, particularly preferably 60 ° C to 15 ° C
0 ° C. or less. If the boiling point of the washing solution at atmospheric pressure is significantly lower than the above range, the handling of the washing solution tends to be difficult.If the boiling point is extremely high, the washing solution is transferred when the target compound is moved to the compound recovery zone in the separation step. Tends to increase. The liquid content (weight ratio to the solid content of the adhering liquid in the cake) of the cake separated and optionally washed is 50% or less, preferably 30% or less, more preferably 20% or less, particularly Preferably it is 15% or less.

(C) Drying Step The type of the drying apparatus used in the present invention is not particularly limited as long as each operation of the drying step described below can be performed, but it is usually a discharge valve (hereinafter simply referred to as a valve). Is used.
The separated cake is held in the chamber 4 and extracted to the powder tank (compound recovery zone) 6 by the valve 5 while controlling the powder surface as needed. Chamber 4 and separation device 3
Are substantially the same pressure. The pressure of the powder tank 6 is lower than that of the separation device 3, and is preferably atmospheric pressure. By releasing the pressurized cake in the chamber 4 to the atmospheric pressure through the valve 5, the boiling point of the cake adhering liquid is lowered, and the cake adhering liquid evaporates by sensible heat due to the boiling point difference. Therefore, in the present invention, it is important that the internal energy that can be used as sensible heat is left more consistently than the reaction. Therefore, the reaction product, cake, target compound, etc. are subjected to the temperature and pressure until passing through the valve 5 in the reaction step (A), the intermediate treatment step (D), the separation step (B), and the drying step (C). In each of the steps, each step maintains a temperature equal to or higher than the boiling point of the liquid present in each form at the atmospheric pressure, and each step maintains a pressure higher than the atmospheric pressure.

There are no particular restrictions on the amount of cake collected in the chamber 4 and the frequency of withdrawal as a method for extracting the cake.
The cake may always stay in the chamber 4 or may be emptied intermittently. The valve 5 can be kept open while the pressure of the chamber 4 is kept high relative to the powder tank 6, but intermittent opening and closing are preferable because gas sealing is essential. The measurement of the cake amount in the chamber 4 is indirect and direct without any particular limitation. Generally, in order to detect the position of the cake surface, an electric contact type detector or a distance measuring device using light or sound waves is used.

A single or a plurality of extraction valves can be provided from the separation device 3 to the compound recovery zone, and another valve can be added before the valve 5 closest to the compound recovery zone. Examples of the valve 5 or 9 include a ball valve, a butterfly valve, a rotary valve, a flap damper, a slide damper, a spindle valve, and the like. When extracting with two valves as exemplified by the valve 5 and the valve 9, for example, by alternately opening and closing the valve 5 and the valve 9, the cake may be intermittently accumulated in the intermediate chamber 16 and discharged from the valve 5. It is possible. Further, the cake may be discharged from the valve 5 by sealing the intermediate chamber 16 as required, appropriately performing heating, cooling, pressurizing, depressurizing, and gas replacement. In the mode of continuously discharging the cake, the release timing of the valve 9 and the release timing of the valve 5 are controlled so as not to overlap, and the release time is preferably 0.5 seconds to 20 seconds, more preferably 1 second to
It is 15 seconds, particularly preferably 2 seconds to 10 seconds. Specifically, the specifications of the heat exchanger, gas injection, gas purge, and the like can be given. Further, it is also possible to reduce the pressure difference before and after each valve by controlling the opening and closing timing of the valve by increasing the number of intermediate chambers connected in series by adding a valve.

These valves are characterized by the shape of the seal portion. For example, there are surface contact and line contact, and the line contact also has a square or circular shape. As an application example of the present invention, when a plurality of valves having an intermediate chamber are used, the shape of the seal portion is not particularly limited. However, when the compound is discharged from the separation device to the compound recovery zone with a single valve, preferably, the seal portion has a line contact and is circular. Specifically, a spindle-type valve having a substantially conical valve body is used. If it is in line contact, there are few sliding parts and there is an effect of suppressing solid entrapment. Further, a spindle-type substantially conical valve body valve having a circular seal portion shape can be driven at high speed. In the case of a single valve, if the release time is long in the drying step, the pressure in the separation step and the previous step will also leak, so it is preferable to appropriately control the release time, for example, an operation of repeating release and closing . Its release time is preferably 0.0
1 to 1 second, more preferably 0.02 to 0.5 second, particularly preferably 0.04 to 0.2 second, and most preferably 0.02 to 0.2 second.
5 to 0.15 seconds. FIG. 2 shows a pressure drying apparatus provided with a valve of this type.

The cake discharged from the separation device is transferred to the chamber 4. According to the example of FIG. 2, the chamber 4 is separated from the chute 7 by a seal 22 provided on a substantially conical valve body. When the amount of the cake is accumulated to an appropriate amount by the detector 21, the cylinder 24 connected to the oil unit is driven to lower the valve 5, and the seal 22 is opened to discharge the cake. The discharged cake passes through a chute and is transferred to a powder tank. Also,
The seal 23 blocks the chute 7 from the outside air. The inner surfaces of the chamber 4 and the chute 7 are subjected to a treatment for preventing adhesion as required. The seal 22 has a high temperature and a high stress,
A material and shape that can withstand friction are selected.

In addition to the method of completely shutting off the chamber and the powder tank by using a valve, there is also a method of using a screw conveyor instead of the discharge valve and sealing with a cake in the screw conveyor. In this case, the cake is transferred from the chamber to the powder tank by the screw conveyor. Some or all of the cake adhering liquid is removed by evaporating from the cake transferred to the compound recovery zone due to a temperature difference.However, in order to prevent recontamination by the evaporated cake adhering liquid, dry gas is supplied to the compound recovery zone or the intermediate zone. Preferably, it is introduced into the chamber 16. As the drying gas, any inert gas can be used as long as it is inert to the compound and the adhesion liquid and is not saturated in the composition of the adhesion liquid. For example, a rare gas such as nitrogen gas, argon, or neon can be used. Used.

When the cake in the chamber 4 moves to the powder tank 6, the adhered liquid evaporates due to the opened internal energy, and the liquid content of the cake is reduced.
Or more, more preferably 6% or more, particularly preferably 9%
Or more. Here, the decrease in the liquid content of the cake by 3% means that the liquid content of the cake decreases from 15% to 12%, for example. Further, the liquid content of the cake can be reduced to 10% or less, preferably 5% or less, more preferably 2% or less, and the cake is preferably stored in a powder tank as powder having a low liquid content.

The cake adhering liquid is a reaction medium, a washing liquid, a reaction by-product, a reaction substrate, other additives and the like, and a mixture thereof, and is mainly a reaction medium or a washing liquid or a mixture thereof. The effect of the present invention is that the latent heat of evaporation of the cake adhering liquid at atmospheric pressure is 300 kcal / k.
g, particularly preferably 250 kcal / kg or less, more preferably 200 kcal / kg or less,
For example, it is 150 kcal / kg or less. When the cake adhering liquid is a mixture, the latent heat of evaporation is determined as an average value of the mixture. The adhering liquid evaporates to a gas, and the evaporative gas is discharged from the line 14 and collected as needed.

The target compound extracted into the powder tank 6 is recovered through the line 15. If the liquid content exceeds the acceptable range for the product, it will be necessary to pass through a dryer,
In that case, the intermediate tank 1 can be used without performing the heating and drying operation.
It is preferable to dry the compound by introducing a drying gas into the powder bath 6 or the powder tank 6.

The difference between the temperature of the cake in the separator and the temperature of the cake discharged to the compound recovery zone is preferably 5 ° C. to 25 ° C.
0 ° C, more preferably 10 ° C to 200 ° C, particularly preferably 20 ° C to 170 ° C. If the temperature is significantly lower than the above range, the drying becomes insufficient, and if the temperature is significantly higher than the above range, the temperature of the cake in the separator becomes too high, so that the decomposition of the compound may occur. The difference between the pressure in the separator and the pressure in the compound recovery zone is preferably 0.01 MPa to 22 MPa, more preferably 0.1 MPa to 22 MPa.
11 MPa to 12 MPa, particularly preferably 0.21 MP
a to 7 MPa. If the amount is significantly smaller than the above range, it becomes difficult to discharge the cake, and if the amount is significantly larger than the above range, the discharge becomes abrupt and control becomes difficult. The volume average particle size of the cake discharged from the separation device is preferably 4
It is at least 0 μm, more preferably at least 50 μm, particularly preferably at least 60 μm. If it is significantly smaller than the above range, the liquid removal will be poor. There is no upper limit, but usually 3
It is not more than 00 μm.

The relative relationship between the temperature and the pressure in the above-mentioned reaction step (A), intermediate treatment step (D) and separation step (B) is as follows. The temperature is not limited except that the above temperature is maintained and each step is maintained at a pressure higher than the atmospheric pressure. For example, regarding the temperature, the temperature of the reaction step (hereinafter T
A)> Temperature of intermediate treatment step (hereinafter TD)> Temperature of separation step (hereinafter TB), TA> TD <TB, TA
Any case where <TD <TB is applicable to the present invention. Also, in the relationship between the reaction step and the separation step, TA <T
B, TA> TB. The same applies to the pressure, and the pressure during the reaction step (hereinafter PA)> the pressure during the intermediate treatment step (hereinafter PD)> the pressure during the separation step (hereinafter P)
In the case of B), PA> PD <PB, PA <PD <P
In the case of B, any of the cases of PA <PB and PA> PB may be used. Further, the relationship between the temperature and the pressure does not necessarily need to be linked. For example, if the pressure is increased in the intermediate treatment step and passed through a cooler, the temperature becomes PA> PB, but the pressure becomes PA> PB.
<PB.

Next, the production method of the present invention is applied to those which are recovered as solids as target compounds. The compound produced by the production method of the present invention may be any compound as long as it is stably present in each of the above-described steps and at least partially exists as a solid before at least the separation step. And more preferably an aromatic dicarboxylic acid, and particularly preferably terephthalic acid.

Since the production method of the present invention includes a solid-liquid separation step and the target substance is recovered as a solid, the unreacted raw material is itself a liquid or a reaction medium and / or Alternatively, a compound having higher solubility in a washing solution is preferable because the purity of the target compound can be increased.

In a preferred embodiment of the present invention,
Liquid phase oxidation of alkylbenzene with molecular oxygen. By this reaction, an aromatic carboxylic acid such as an aromatic monocarboxylic acid, an aromatic dicarboxylic acid, or an aromatic tricarboxylic acid, and a product obtained by oxidizing some of the alkyl groups thereof are obtained. According to the method of the present invention, a description will be given below as applied to the production of terephthalic acid as a representative example. In addition, paraxylene is mentioned as an alkylbenzene used as a raw material.

Liquid phase oxidation of para-xylene usually uses acetic acid as the reaction medium. The amount of the reaction medium used is usually 1 to 10 times by weight, preferably 2 to 8 times the weight of para-xylene.
The weight ratio is more preferably 3 to 6 times by weight. Also, in addition to acetic acid, usually 25% by weight or less, preferably 10% by weight
The following water may be contained. Further, in the liquid phase oxidation reaction of para-xylene, water is generated, and the water concentration in the reaction medium, together with the water originally contained in the solvent, is usually at most 5 to 25% by weight, preferably 7 to 25% by weight. It is controlled to be 20% by weight. The adjustment of the water concentration can be carried out by purging a part of the condensed reflux liquid obtained by condensing the gas volatilized from the reactor out of the system according to a conventional method.

As the molecular oxygen-containing gas used in the oxidation of para-xylene, air, oxygen-diluted air, oxygen-enriched air and the like are used, but air is desirable from the viewpoint of equipment and cost.

As the catalyst in the oxidation reaction, any known catalyst can be used, but typically cobalt, manganese and bromine are mainly used. As a specific compound of the catalyst component, examples of the cobalt compound include cobalt acetate, cobalt naphthenate, and cobalt bromide, and among them, cobalt acetate is preferable. Examples of the manganese compound include manganese acetate, manganese naphthenate, and manganese bromide. Among them, manganese acetate is preferable.
Examples of the bromine compound include hydrogen bromide, sodium bromide, cobalt bromide, manganese bromide, and bromoethane, with hydrogen bromide being preferred. These compounds may be used in combination. Further, other metal components may be present in the acetic acid solvent. For example, when the sodium component is present at 1 ppm or more and 100 ppm or less,
Further, it has a role of preventing precipitation of a manganese component and has an effect of improving the transmittance of the obtained terephthalic acid.

The amount of the catalyst used is such that the amount of the cobalt component used is 100 ppm by weight or more and 2000 ppm by weight or less, preferably 200 wt.
pm or more and 1000 ppm by weight or less. The use amount of the manganese component is 1 ppm by weight or more and 1000 ppm by weight or less, preferably 5 ppm by weight or more and 500 ppm by weight or less. The amount of bromine used is 400 ppm or more and 200
It is 0 ppm or less. Further, a co-oxidizing agent can be used in combination for promoting the reaction. The reaction medium contains reaction intermediates such as 4-carboxybenzaldehyde, paratoluic acid, and paratolualdehyde, and impurities such as benzoic acid.

In the oxidation reaction of para-xylene, in an acetic acid solvent,
In the presence of a catalyst containing cobalt, manganese, and bromine,
95% or more of para-xylene is oxidized while continuously supplying a molecular oxygen-containing gas at a temperature of 40 ° C to 230 ° C, preferably 150 ° C to 210 ° C. This is called the first reaction zone. The reaction pressure is at least the pressure at which the mixture can maintain a liquid phase at the reaction temperature, and is usually 0.2 to 5 MPa.
It is. The oxidation reaction time (average residence time) is usually 30 to
300 minutes. In the first reaction zone, the oxidizing exhaust gas obtained by condensing and removing condensable components from the gas extracted from the reactor is branched into two streams in order to increase the oxygen partial pressure in the gas phase of the reaction system. It is also possible to use a method of discharging to the outside and continuously circulating the other to the reactor.

Next, if necessary, 130 ° C. to 240 ° C., preferably 140 ° C. to 220 ° C., more preferably 160 ° C. to 220 ° C.
A second reaction zone at between 200C and 200C can be provided. In this zone, low-temperature re-oxidation is performed with molecular oxygen without adding para-xylene. The reaction time (average residence time) of the low temperature additional oxidation is usually 20 to 90 minutes. Next, if necessary, in the third reaction zone at a temperature higher than the second reaction zone of 150 to 300 ° C., preferably 200 to 280 ° C., additional oxidation can be carried out with molecular oxygen without adding para-xylene. . The reoxidation reaction time (average residence time) is 5 to 120 minutes.

The oxidation reaction may be terminated in the first reaction zone, or may be performed up to the second reaction zone or the third reaction zone. According to the definition herein, the last reaction zone in the selected process corresponds to the reactor 1 in FIG. For example, if the operation is performed up to the third reaction zone,
Correspond to the reactor 1. According to the above example, the slurry led to the intermediate treatment step from the line 12 in FIG.
To 300 ° C. This intermediate processing may be performed,
The transfer may be directly performed from the line 13 to the separation step 3 without being performed. For example, when the reaction is carried out up to the second reaction zone in the case of terephthalic acid, a slurry at 130 ° C. to 240 ° C. is obtained, but crystallization is not required, so that the slurry is transferred to the separation device while maintaining the reaction temperature. The pressure of the slurry is equal to or higher than the vapor pressure of the mother liquor in the slurry. When the pressure is reduced, the temperature also decreases. Therefore, actually, the temperature of the slurry is controlled by manipulating the pressure of the slurry.

The temperature of the slurry supplied from the line 13 in FIG. 1 to the separation device is determined in consideration of the amount of cake adhering liquid to be evaporated from the cake. For example, assuming that a mixed solution having a water concentration of 10% by weight and an acetic acid concentration of 90% by weight in the reaction medium adheres to the terephthalic acid cake at a weight ratio of 11%, the mother liquor adhered to the cake is completely evaporated. The required cake temperature is 170 ° C. or higher. Therefore, the slurry obtained by carrying out the reaction up to the second reaction zone is, for example, 1 slurry.
It is preferred to carry out the reaction in the second reaction zone at a temperature between 30 ° C and 240 ° C but above 170 ° C. Note that 170
Even if the reaction is carried out at a temperature lower than ℃, if it is maintained at a temperature higher than the boiling point under atmospheric pressure of 110 ℃, the difference from the actual cake temperature is industrially used for cake drying as sensible heat It is possible to do.

Therefore, keeping the temperature above the normal pressure boiling point without releasing the slurry pressure to the atmospheric pressure in the process after the reaction is important from the viewpoint of energy utilization in the present invention. However, if only a slurry of 170 ° C. or less is obtained in the illustrated case, the amount of heat insufficient for drying the cake must be compensated for, and heating is performed on any of the slurry before separation, the cake after separation, and the cake after discharge. . Use of a heat exchanger for slurry before separation, heating of washing liquid and heating of gas atmosphere for cake after separation, heating of powder atmosphere from outside of powder tank and heating of gas atmosphere for cake after discharge Update and the like. In order to maintain the slurry at 170 ° C. or more, a pressure of 0.6 MPa or more is required, and the pressure of the separator is preferably 0.65 MPa or more and 1.5 MPa or less, more preferably 0.7 MPa or more and 1.3 MPa or less, and particularly preferably. Is 0.8MPa
Not less than 1.0 MPa.

The temperature of the cake washing liquid is preferably equal to or higher than that of the cake so as not to carry away the heat energy of the cake. As a specific example, if the cake temperature is 170 ° C., a cleaning liquid containing acetic acid at 170 ° C. or higher as a main component, for example, a cleaning liquid higher by 5 ° C. or higher is prepared. Further, in order to avoid bumping of the cleaning liquid, the pressure in the separation device for introducing the cleaning liquid is set to be higher than the vapor pressure of the cleaning liquid. For example, it is preferable that the pressure in the separator is higher than the vapor pressure of the slurry supplied to the separator by 0.01 to 1.0 MPa, and the vapor pressure of the cleaning liquid falls within this range. The type of cake washing liquid is 300 Kca by accumulating the latent heat of evaporation of each component.
It is preferably 1 / kg or less. Although the latent heat of vaporization of water alone is 500 kcal / kg or more, it is preferably used even if water is contained as long as the mixture has an average latent heat of vaporization of 300 kcal / kg. Also,
The composition of the cleaning liquid may be completely different from the reaction medium. For example, in the case of the reaction medium containing acetic acid as a main component in the above example, the cleaning liquid may be completely different, for example, a pure substance of acetic ester, or may be the same component as the reaction medium except for impurities.

The terephthalic acid cake leaving the separator is shown in FIG.
Stays in the chamber 4 illustrated in FIG. The cake is withdrawn intermittently or continuously into a powder tank at atmospheric pressure. The average value of the cake retention amount in the chamber 4 is preferably 0.0001 to 0.1 in terms of weight ratio, for example, assuming that the processing amount per hour is 1, and depends on the shape of the chamber and the setting of the cake amount upper limit and the cake amount lower limit. . The extraction amount is determined from the upper and lower limits of the cake in the chamber 4 and the retained amount. For example, if the processing amount per hour is 1, the discharge amount per drive of the valve 5 is 0.002 to 0.02. The driving distance of the valve 5 is 3 ~
It is preferably 50 mm, more preferably 10 to 25 mm. The driving frequency is preferably 50 to 500 times / hr. By setting the driving distance and the driving frequency within the preferable ranges, the discharge of the compound from the separation device to the compound recovery zone is improved.

The terephthalic acid cake discharged into the powder tank 6 illustrated in FIG.
Recovered from. The gas containing acetic acid as a main component and the introduced dry gas generated in the atmospheric pressure system are removed from the line 14. The cake recovered from the line 15 becomes a product through further purification steps as necessary.

[0056]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the scope of the invention.

COMPARATIVE EXAMPLE 1 In a facility where the production of terephthalic acid is 36 Ton / hr, paraxylene, acetic acid, cobalt acetate, manganese acetate, hydrogen bromide 5.5 times by weight of paraxylene were continuously fed into the liquid phase oxidation reactor. At a temperature of 197 ° C. and a pressure of 1.45M.
The oxidation reaction was performed at pa and a reaction time (average residence time) of 90 minutes. The amount of the catalyst used is such that the amount of the cobalt component is 280 ppm by weight, the amount of the manganese component is 280 ppm by weight, and the amount of the bromine component is 700 ppm relative to the solvent in terms of cobalt metal.

Air is used as a gas for performing an oxidation reaction by molecular oxygen. At this time, the oxygen content of the air is 21%. Then, compressed air was supplied into the reactor such that the oxygen concentration in the gas discharged from the reactor (hereinafter sometimes referred to as waste gas) became 5% by volume. Next, the oxidized slurry was continuously transferred to a low-temperature post-oxidation reactor, and air (oxygen content 21%) was used as a gas for performing an oxidation reaction at a temperature of 190 ° C., a pressure of 1.3 MPa, and a reaction time (average residence time) of 35 minutes. Was supplied so that the oxygen concentration in the waste gas became 6% by volume, and low-temperature additional oxidation was performed.

The low-temperature reoxidation slurry was continuously crystallized in a three-stage intermediate treatment tank, and subjected to solid-liquid separation at atmospheric pressure. At this time, the liquid content of the cake separated into solid and liquid was 15.0.
%Met.

Next, the cake was dried at atmospheric pressure using a steam tube drier using steam as a heating source. Steam having a pressure of 0.4 Mpa is circulated around the dryer to heat the drying oven. The cake adhering liquid evaporated by heating is taken out of the system by the nitrogen gas flowing in the dryer. The outlet temperature of the dryer is 140 ° C. When 1 Ton terephthalic acid was dried by this dryer, the calorific value of the steam used in the dryer was 36000 Kcal. The liquid content of the obtained terephthalic acid was 0.1%. Therefore, when the terephthalic acid cake is dried at atmospheric pressure from a liquid content of 15.0% to a liquid content of 0.1%, 1T of terephthalic acid is required.
A heat of 36000 Kcal is required per on.

Example 1 Next, the production method according to the present invention, ie, the phenomenon that occurs when the solid and liquid are separated while maintaining the pressure and temperature generated in the reaction step, and the cake is transferred to a zone lower than the separation zone. An experiment was conducted to verify the effect of evaporating and separating the cake adhering liquid using the heat difference. The cake obtained by the same method as in the comparative example was dried by flash separation using the equipment shown in FIG.

The flash separation device is used to heat the heater 32 having a capacity of 1.2 liters (a cylindrical shape having an inner diameter of 40 mm and a length of 800 mm), a receiver 34 having a capacity of 3 liters (compound recovery zone), and a heater. Jacket 38,
The receiver can be immersed in an oil bath 35 for heating or cooling. A cake having a liquid content of 14.1% (a solid content of 700%) obtained by the same method as in Comparative Example 1.
g equivalent: composition of the cake adhering liquid having a water concentration of 10% -acetic acid concentration of 90%) from the upper valve 31 to the heater 3 under atmospheric pressure.
2 If heated as it is, part of the acetic acid and water adhering to the cake would evaporate and the amount contained in the cake would change. The amount was added to the heater in advance, and then the heater was closed and the temperature was raised to 173 ° C. At this time, the pressure in the heater was 0.6 MPa.

In the receiver located below the heater, the interior of the receiver is vaporized so as to have an acetic acid vapor atmosphere, and an amount of acetic acid corresponding to the volume thereof is charged in advance, and then the receiver is set to 11
It was immersed in a heating medium oil at 5 ° C. Then, the bottom valve 33 was opened, and the cake in the heater and the vaporized adhering liquid were transferred to a receiver at atmospheric pressure. Since the pressure of the heater immediately became atmospheric pressure, the bottom valve of the heater was immediately closed, and the valve 36 between the receiver and the trap container 37 containing ethylene glycol was closed. The temperature inside the receiver is 123 ° C
Then it was cooled down. If the receiver is opened to the atmosphere after the flash separation, the true value is difficult to measure because the liquid components remaining on the cake surface diffuse rapidly into the atmosphere. For this purpose, the receiver is cooled in a closed system, and the gas components in the gas phase of the receiver are condensed. Specifically, the receiver is cooled sufficiently to 20 ° C. where almost no acetic acid or water vapor is generated. The entire cake containing acetic acid inside was recovered. It was confirmed that both the method of obtaining the amount of the cake adhering liquid from the weight loss after drying the cake and the analysis of the composition in the liquid obtained by washing the cake surface with water were identical.

Acetic acid and water vapor discharged through a receiver by flash separation are introduced into a container containing ethylene glycol and water and absorbed, and then the amount of acetic acid and water is increased in weight and the liquid component in the container is converted into gas. Analysis by chromatography confirmed the mass balance. The value obtained by subtracting the amount of acetic acid present in the gas phase of the receiver before cooling the receiver from the amount of cake adhering liquid thus obtained is defined as the amount of liquid adhering to the cake immediately after flash separation. The rate was determined. The median diameter of this cake is 99
μm. Analysis of the median diameter was performed using a laser scattering particle size distribution analyzer “Lazer Micro” manufactured by Seishin Enterprise.
n Sizer / LMS-24 "was used. 1 g of the recovered cake and a surfactant were placed in a water-filled sample chamber of the apparatus. Thereafter, the dispersion under the ultrasonic wave for 30 seconds and the analysis by the laser scattering automatically proceed. When the analysis is completed, a volume frequency distribution for each particle size section is obtained. From the results, the particle size at which the cumulative frequency became 50% was calculated.

Example 2 Example 1 was the same as Example 1 except that the composition of the cake adhering liquid having a water concentration of 10% and the acetic acid concentration of 90%, the liquid content of the cake was 10.4%, and the temperature of the heater was 187 ° C. Flash separation was performed in the same manner as described above. Receiver temperature after flash separation is 11
It was cooled at 0 ° C. and cooled.

Example 3 In Example 1, the composition of the cake adhering liquid having an acetic acid concentration of 100%, the liquid content of the cake was 15.0%, and the temperature of the heater was 144 ° C.
Flash separation was performed in the same manner as in Example 1 except that

Table 1 shows the working conditions of Examples 1 to 3, and Table 2 shows the results. In each case of Examples 1 to 3, it is assumed that the separation step and the drying step are performed while maintaining the temperature and pressure generated in the reaction step. Therefore, other than the temperature and pressure generated in the reaction step, no new energy is used in the drying step. In Example 1, the liquid content was 14.1% to 1.3%, in Example 2, the liquid content was 10.4% to 0.1%, and in Example 3, the liquid content was 15.0. % To 5.7%, respectively, without any additional heat being applied.

Further, as shown in Table 2, the cake liquid content after the flash separation operation matched the amount calculated from the enthalpy of the system. Accordingly, it is shown that by employing the production method of the present invention, the internal energy generated in the reaction step can be effectively used for the drying step, and a large amount of heat energy conventionally required in the drying step can be saved. Was done.

[0069]

[Table 1]

[0070]

[Table 2]

[0071]

According to the method of reheating and drying after separating solid and liquid under atmospheric pressure, a large amount of heat is required, because terephthalic acid itself needs to be heated in addition to the mother liquor medium to be evaporated. On the other hand, in a method in which solid-liquid is separated while maintaining the temperature at or above atmospheric pressure and then dried under pressure, the energy consumed for drying can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an example process for implementing the present invention.

FIG. 2 is a schematic view of an example of a preferred flash tank for carrying out the present invention.

FIG. 3 is a schematic view of a flash tank used in an example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reactor 2 Intermediate processing tank 3 Separation device 4 Chamber 5 Discharge valve 6 Powder tank (compound recovery zone) 7 Chute 8 Substantially conical valve element 9 Upper valve 11 Raw material etc. introduction line 12 Reactant transfer line 13 Reactant transfer Line 14 Evaporated gas discharge line 15 Compound recovery line 16 Intermediate chamber 21 Detector 22 Seal 23 Seal 24 Cylinder 31 Upper valve of heater 32 Heater 33 Bottom valve of heater 34 Receiver (compound recovery zone) 35 Oil bath 36 Receiving Valve between vessel and trap 37 trap 38 jacket

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F26B 5/14 F26B 5/14 // C07B 61/00 300 C07B 61/00 300 (72) Inventor Katsunori Fukuda Mitsubishi Chemical Co., Ltd. (1-1) Kurosaki Castle Stone, Kitakyushu City, Fukuoka Prefecture (72) Takayuki Isogai 1-1, Kurosaki Castle Stone, Yawata Nishi Ward, Kitakyushu City, Fukuoka Prefecture Mitsubishi Chemical Corporation (72) Inventor Katsuya Ando Tokyo 3-9-2, Nihonbashi, Chuo-ku Tomoe Industry Co., Ltd. F-term (reference) 3H052 AA01 BA03 BA35 CA23 DA06 EA06 EA07 3L113 AC23 AC67 BA39 CB40 DA02 4G075 AA03 AA13 AA22 AA35 AA41 BA06 BA10 BB02 CA54 CA02 DA01 DA02 DA18 EC09 ED01 ED03 ED04 ED11 4H006 AA02 AC46 BA16 BA20 BA32 BB11 BC10 BC11 BC14 BD80 BD84 BJ50 BS30 4H039 CA65 CC30

Claims (24)

[Claims] (A) a reaction step in which a reaction is carried out in a reactor at a pressure higher than the atmospheric pressure and at a temperature equal to or higher than the boiling point of the reaction medium at the atmospheric pressure to produce a compound; At a pressure higher than the atmospheric pressure and a temperature higher than the boiling point of the reaction medium at the atmospheric pressure, a certain amount or more of the reaction medium is separated from the slurry containing the compound and the reaction medium, and the weight ratio of the cake adhering liquid to the solid content is 50% or less. And (C) transferring the obtained cake to a compound recovery zone at a pressure lower than the pressure in the separator and lower than the temperature in the separator, and releasing the internal energy released by the transfer. A method for producing a compound having a drying step of evaporating a cake adhering liquid by the method. 2. In the separation step (B), the cake is heated at a pressure higher than the atmospheric pressure and at a temperature not lower than the boiling point at the atmospheric pressure and the latent heat of vaporization at the boiling point at the atmospheric pressure is 300 kcal / kg or less. The method for producing a compound according to claim 1, wherein the compound is washed with a washing solution. 3. The method according to claim 1, wherein the latent heat of vaporization at a boiling point of the reaction medium at atmospheric pressure is 300 kcal / kg or less.
The method for producing a compound according to the above. 4. In the separation step (B), the cake is washed with a washing solution having a temperature in the range from the boiling point of the washing solution at atmospheric pressure to “TB1 + 100 ° C.” (TB1 indicates the temperature (° C.) of the unwashed cake). A method for producing the compound according to any one of claims 1 to 3. 5. The method according to claim 1, wherein in the separation step (B), the cake is washed with a washing solution 0.03 to 5.0 times the weight of the solid content in the cake. Production method. 6. The method for producing a compound according to claim 1, wherein the compound formed in the reaction step (A) is an aromatic carboxylic acid. 7. The method according to claim 6, wherein the aromatic carboxylic acid is terephthalic acid. 8. The process for producing a compound according to claim 6, wherein in the reaction step (A), an aromatic compound is obtained by subjecting an alkyl group-substituted aromatic compound to liquid phase oxidation with molecular oxygen to obtain an aromatic carboxylic acid. 9. The process according to claim 7, wherein in the reaction step (A), paraxylene is oxidized in a liquid phase with molecular oxygen to obtain terephthalic acid. 10. The reaction step (A) is performed at 50 ° C. or more and 350 ° C.
The method for producing a compound according to any one of claims 1 to 9, which is performed in a temperature range of not more than ° C. 11. The method according to claim 1, wherein the reaction step (A) is carried out at a pressure exceeding atmospheric pressure.
The method for producing a compound according to any one of claims 1 to 10, which is performed in a pressure range of not more than MPa. 12. The method according to claim 1, wherein in the drying step (C), the difference between the temperature of the cake in the separation device and the temperature of the cake discharged to the compound recovery zone is 5 ° C. to 250 ° C. A method for producing a compound. 13. In the drying step (C), the pressure difference between the pressure in the separation apparatus and the pressure in the compound recovery zone is 0.01 MPa to 2 MPa.
The method for producing a compound according to any one of claims 1 to 12, wherein the pressure is 2 MPa. 14. The method for producing a compound according to claim 1, wherein the discharged compound has a median diameter of 40 μm or more and 300 μm or less in the drying step (C). 15. The method according to claim 1, wherein in the drying step (C), the weight ratio of the cake adhering liquid to the solid content is 10% or less.
15. The method for producing a compound according to any one of the above items. 16. The method according to claim 1, wherein in the drying step (C), the weight ratio of the cake adhering liquid to the solid content is reduced by 3% or more. 17. The drying step (C), wherein an intermediate chamber is provided between the separation device and the compound recovery zone.
7. A method for producing the compound according to any one of the above items 6. 18. The method for producing a compound according to claim 1, wherein a drying gas is introduced into the intermediate chamber and / or the compound recovery zone in the drying step (C). 19. The method for producing a compound according to claim 1, wherein in the drying step (C), the pressure in the compound recovery zone is atmospheric pressure. 20. The method for producing a compound according to claim 1, wherein in the drying step (C), a pressure drying device equipped with a discharge valve is used. 21. The method for producing a compound according to claim 20, wherein the contact portion between the valve body and the valve seat of the discharge valve is linear and circular in shape. 22. In the drying step (C), the discharge valve is intermittently opened, and the release time is 0.01 second to
22. The method for producing a compound according to claim 20, wherein the time is 1 second. 23. An intermediate treatment step (D) in which a compound is crystallized or dissolved between the reaction step (A) and the separation step (B).
The method for producing a compound according to any one of claims 1 to 22, comprising: 24. The method for producing a compound according to claim 1, wherein the compound produced in the reaction step (A) is obtained as a solid.