JP3244636B2 - Method for producing aromatic mononitro compound - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an aromatic mononitro compound by nitrating an aromatic compound using a mixed acid containing nitric acid. More specifically, the present invention relates to a method for producing an aromatic mononitro compound in a reactor having a specific structure.

[0002] Aromatic mononitro compounds include dyes, pigments,
It is an industrially useful compound used as a raw material or intermediate for industrial chemicals, or reduced to an aromatic amino compound to be used as a raw material for polymer materials such as polyamide and urethane.

[0003]

2. Description of the Related Art A method for producing an aromatic mononitro compound has been well known for a long time. For example, when nitrobenzene is used as an example, industrially, benzene is produced from nitric acid, sulfuric acid and water by a batch method or a continuous method. It is produced by reacting with a mixed solution (called a mixed acid), and is usually performed at a controlled temperature of 60 to 70 ° C. while removing heat of reaction. In this case, the mixed acid is used with a high concentration of nitric acid of 20-30%, and the ratio of mixed acid to benzene is usually 3%.
４4: 1. The used acid is substantially free of nitric acid, and generally becomes a 70% sulfuric acid waste liquid.
It is concentrated to 5% and reused. The problem with this method is the large scale cooling and temperature control required to remove the heat of reaction and the large amount of utility required to concentrate and reuse the spent acid after use.

Utilizing the reaction to increase the reaction rate without dissipating most of the heat of mixing and heat of reaction, it is effective to concentrate the high temperature spent acid by a method such as flash evaporation. A so-called adiabatic process which is used in US Pat. No. 2,256,999 has been proposed (called the Kastner method). The mixed acid used in the Kastner method is a mixture of 75% sulfuric acid and 63% nitric acid, and the nitric acid concentration in the mixed acid is 10% or less.
Specifically, it was 3%. The reaction initiation temperature is about 90
The method is carried out by dropping benzene into a stirred tank reactor at a temperature of ° C.

In this method, (1) the residence time is long,
(2) It is difficult to control the reaction, (3) The temperature is easily raised, (4) The side reaction such as dinitrobenzene is easily generated, and (5) The reaction is likely to be dangerous because of the presence of the gas phase. And the like, and it is said that the Kastner method has not been industrially successful.

Thereafter, a method for producing nitrobenzene by an adiabatic process, which is an improvement of the Kastner method, was proposed by Alexander et al. (Japanese Patent Publication No. 20534/1986 and Japanese Patent Application Laid-Open No. 54-32424). Each of these methods specifies the use of a mixed acid having a specific composition of 1 to 8.5% nitric acid, 60 to 70% sulfuric acid and 25% or more water as reaction conditions. By reacting under such conditions, dinitrobenzene as a by-product can be suppressed to 500 ppm or less. They also state that "strong stirring" is required to disperse the benzene, and all use a stirred tank reactor.

[0007] Mixing using a stirring vessel essentially produces a gas phase. The presence of a gas phase containing an organic compound such as benzene at high temperatures in a system where nitric acid is present, such as a nitration reaction, has the danger of explosion and is undesirable. There is a need for a device that does not.

[0008] Under adiabatic reaction conditions, the reaction temperature is necessarily high, and the longer the reaction product is exposed to the high temperature, the more undesirable by-products increase. Therefore, when producing an aromatic mononitro compound by an adiabatic reaction process, it is required to promote the reaction as much as possible and complete the reaction in a short time.

A method for producing an aromatic mononitro compound also includes forming a stream of a mixed acid or benzene into fine droplets of 10 μm or less using an atomizing nozzle or a similar orifice and blowing the stream into one stream with a turbulent jet stream. A method for producing nitrobenzene by accelerating the reaction has been proposed (US Pat. No. 4,973,770). However, even in this method, the reaction rate reaches only about 55% with a residence time of about 3 minutes, and it is estimated that it takes 6 minutes or more to complete the reaction.

Further, a mixed acid in a specific range (nitric acid concentration: 3%) such that the contained nitric acid is completely dissociated into nitronium ions.
The following method has been proposed for nitrating in a tubular reactor (US Pat. No. 5,313,009).

US Pat. No. 4,453,027 discloses a method for producing halonitrobenzene by adiabatic nitration using a mixed acid having a specific composition.

[0012] Recently, with respect to the adiabatic nitration method of toluene or chlorobenzene, a method has been disclosed in which a certain range of mixing energy is added as stirring power in order to vigorously mix the reaction participants (Japanese Patent Laid-Open No. 7-1995).
-258173, JP-A-7-278062).

However, these methods have a problem that the configuration of the reactor and the reaction path are complicated.

[0014]

SUMMARY OF THE INVENTION The method of the present invention solves the above-mentioned problems of the prior art such as a reduction in the reaction rate, an increase in the volume of the reactor, complexity, and safety. It is an object of the present invention to provide an improved method for producing an aromatic mononitro compound having little by-product in a short time.

[0015]

The present invention includes the following arrangement. (1) A plurality of curved plate-like members having a leading edge substantially perpendicular to a trailing edge of the preceding plate-like member and having a conduit and a plate-like member that are sequentially and continuously arranged are not included. Empty tube
The reaction tube combined with
A method for producing an aromatic mononitro compound, characterized in that a mixed acid containing nitric acid and an aromatic compound are allowed to flow through a reactor in which a plurality of conduits and hollow tubes are alternately combined to cause a reaction. (2) The length of the hollow tube is included in the conduit
The method according to (1), wherein the number of plate members is 40 or less . (3) The method according to (1) or (2), wherein the material of the curved plate-shaped member is ceramics. (4) The reaction temperature in the reaction tube is 160 ° C. or lower (1)
Or the method according to (2). (5) The composition of the mixed acid is 1 to 10% by weight of nitric acid and 20 to
Process according to (1) or (2), wherein 40% by weight and the balance is sulfuric acid and / or phosphoric acid. (6) The linear velocity of the fluid in the reaction tube is 20 to 300 cm / s
The method according to (1) or (2), which is ec. (7) The aromatic compound is benzene, toluene, chlorobenzene, naphthalene, or anthraquinone (1)
Or the method according to (2). (8) After the reaction mixture discharged from the reactor is separated into an acid phase and an organic phase, the acid phase is distilled by flash evaporation, the concentration of the separated acid phase is adjusted, and this is returned to the reactor for further reaction ( The method according to 1) or 2).

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a reaction tube includes a conduit having a special shape. This conduit will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a hollow tube having a circular cross section, which is a mixer conduit for reacting a mixed acid and an aromatic compound. Inside the conduit 1, a plurality of curved plate-like members 2 are arranged in series. In FIG. 1, a part of the conduit 1 is cut away to show the inside, and it can be seen that several of these plate-like members 2 are built in the inside. The number of these plate-shaped members 2 can be any number, and the selection of the number will be described later. Each of these plate members 2 is made of a flat plate material having a width substantially equal to the inner diameter of the conduit 1 and a length several times the width. Each plate member 2 is twisted and its front and rear ends have an angle with respect to each other, and the angle is preferably in a range of 60 degrees to 210 degrees. Further, each plate-like member 2 is twisted in the opposite direction to the preceding plate-like member 2, and ends of adjacent plate-like members 2 form an angle, and it is desirable that the angle be 90 degrees. . Instead of reversing the twisting direction of each plate-like member 2 one by one, a plurality of plate-like members 2 twisted in the opposite direction after a plurality of plate-like members 2 twisted in the same direction every several pieces Two can also be arranged. Therefore, the plate-like members 2 are arranged such that right-handed and left-handed groups are alternately arranged, and each group is composed of one or several plate-like members 2. FIG. 2 is an external view showing several curved plate-like members 2 incorporated in the mixer conduit 1 of FIG.

Further, in the adiabatic nitration method, since a strong acid such as sulfuric acid is handled at a high temperature, the corrosion resistance is insufficient with a usual metal material, and the material of the above-mentioned plate member is sufficiently resistant to a strong acid such as sulfuric acid. It is desired that the ceramic has excellent corrosion resistance. For example, alumina, zirconia, mullite,
And silicon carbide.

The conduit having the above-described shape and function includes:
For example, "Chemical Engineers, Hand" by Perry & Chilton
book "Ken to McGraw-Hill Publishing 6th Edition 19-22
Under the name of icsstatic mixer, it is mainly introduced as a device that mixes substances with high viscosity. In Japan,
It is sold by Noritake Company as "Noritake Static Mixer". Fluids are mixed in this type of mixer in three ways: splitting, inverting and diversion. This type of mixer, especially when used in adiabatic nitration reactions, can be used for mixing by a stirrer in a tank vessel or other types of non-driven mixers, such as the Sulzer static mixer, Koch Engineering Co. , Inc.
(1) Compared to (1), the structure is simple, there is no dead space and pressure loss is small, (2) Scale-up is easy, (3) Maintenance is easy, (4) (5) It is easy to stabilize and simplify, (5) A special acid-resistant material such as ceramics can be used, (6)
There are many advantages such as no noise and vibration due to the absence of a drive unit and no failure due to it, and (7) safety because there is substantially no gas phase in the reaction unit.

The aromatic compound and the mixed acid are mixed by using a pump.
The liquid is sent into the conduit at the same time. If the amounts of the liquids of the aromatic compound B and the mixed acid A are significantly different, it becomes difficult to uniformly insert the two liquids into the conduit.
It is preferable to provide the guide tube 3 as described in (1). The outlet of the guide tube 3 is on the extension of the center of the conduit inlet, and the tube diameter of the guide tube is smaller than the tube diameter of the conduit. As the diameter of the guide tube decreases, the linear velocity at the outlet increases, which is effective in improving the mixing state. However, since the pressure resistance of the conduit is also required, the diameter of the guide tube is reduced to 2 m.
m or more. In the adiabatic nitration reaction, it is preferable to provide a guide tube irrespective of the amount of liquid to be sent. As shown in FIG.
Is provided.

The aromatic compound used in the present invention is stable in the presence of hot sulfuric acid and hot phosphoric acid, and is about 40 to 8
Any aromatic compound that can be liquefied in the temperature range of 0 ° C. and whose nitration product is also stable in the presence of hot aqueous sulfuric acid and hot phosphoric acid,
Examples include benzene, toluene, chlorobenzene, naphthalene, or anthraquinone.

In the conduit having the plate-like member 2, there are areas where the finely divided droplets of the aromatic compound that have passed through a certain number of the plate-like members 2 are no longer further reduced. Usually, the number of plate members at the limit is 50 or less, and in some cases, 20 to 30 or less. In the adiabatic nitration reaction, the reaction proceeds even in that region, and the reaction can be completed. Immediately after being miniaturized once, the reaction progress can be maintained even in a hollow pipe having no plate member within a certain period of time, so a conduit having a certain number of plate members and a hollow tube made of glass lining are required. It is also possible to combine them alternately.
A reaction tube that combines a conduit and a hollow tube can reduce the number of conduits required to complete the reaction, compared to a reaction tube that uses only a conduit, and can be changed in size to a device that uses only a conduit. Pressure loss can be reduced. The length of the hollow tube is a length corresponding to 40 or less, in some cases, 20 or less in terms of the number of plate members.

Since the method of the present invention is performed in an adiabatic system,
The amount of heat generated based on the reaction and mixing is determined by the raw material supply conditions such as the mixed acid composition and the molar ratio of the aromatic compound / nitric acid and the amount of reaction based thereon, and the amount of temperature rise is thereby determined. Various combinations of raw material supply conditions are possible,
160 temperature in the system from the viewpoint of safety and by-product control
It is preferred to choose conditions that do not raise the temperature above ° C. Usually, the amount of nitric acid in the mixed acid is 1 to 10%, preferably 1 to 10%.
The composition of sulfuric acid or phosphoric acid and water other than the above can be changed to some extent within a range of a temperature rise amount such that the temperature in the reaction system becomes 160 ° C. or less. In order to keep the temperature in the system below 160 ° C, 50-75
%, Preferably 55-70% sulfuric acid or phosphoric acid, and 20-40%, preferably 28-37% water. In particular, in the case of nitration of chlorobenzene, it is possible to control the isomer ratio of the aromatic nitro compound by selectively using concentrated phosphoric acid and sulfuric acid which are concentrated to a P ₂ O ₅ concentration of 74 to 80%. Such mixed acid and the stoichiometric excess of the stream of aromatic compound are mixed in a static mixer. The reaction is usually 50 to 10
It starts at 0 ° C and reaches 130-150 ° C.

The supply amount of the aromatic compound is preferably at least 1 mole ratio to the nitric acid in the mixed acid. Although it is possible to carry out the reaction at a molar ratio of less than 1 mol, there is a safety problem since unreacted nitric acid remains after the reaction. Therefore, the supply amount of the aromatic compound is usually used in the range of 1 to 3 molar ratio with respect to nitric acid.

Next, the speed of the reaction fluid will be described. Since the optimum reaction rate varies depending on the size of the reactor, reaction conditions, and the like, it cannot be unconditionally determined.
m, the linear velocity passing through the conduit is usually 20 to 3
00 cm / sec, preferably 50 to 150 cm / sec
c. If the linear velocity is less than 20 cm / sec, the reaction rate tends to decrease. In addition, the linear velocity is 300 cm / s
Although it is possible to perform the reaction under conditions exceeding ec, there is a limit to the optimal droplet size at which the reaction proceeds, and even if an excessive amount of energy is added, only a loss is caused. Therefore, there are economical problems such as the necessity of high pressure pumps, pipes, and devices.

The residence time of the fluid in the reaction tube varies depending on the reaction conditions. From 1 second to 5 minutes, the reaction of the present invention is completed in a much shorter time than the known methods so far. As a result, generation of by-products is suppressed.

The reaction mixture discharged from the reaction tube is separated into an organic phase and an acid phase in the separator.
It is desirable to pressurize to a pressure such that the acid phases do not flash evaporate together. The pressure at this time is usually ^{2 to 5} kg / cm ² because the pressure at the inlet of the conduit also increases accordingly.
G, preferably 2-3 kg / cm ² G. The separated acid phase is re-concentrated using known means, for example, a vacuum flash evaporator utilizing the heat generated by the reaction or mixing, and is recycled if necessary. The organic phase can be separated and purified from impurities contained therein by a method usually used for nitration of an aromatic compound, for example, washing, distillation, or the like, to obtain a target aromatic nitro compound.

[0027]

EXAMPLES The method of the present invention will be specifically described below with reference to examples.

Embodiment 1 An inner diameter 1 having eight ceramic plate members alternately formed by twisting a rectangular plate 180 degrees to the left or right inside the plate 1
Using a series of 45 2 mm ceramic Noritake static mixers (model CSM-12-5) connected in series as a conduit, benzene at 24 ° C (abbreviated as Bz)
At a rate of 52 kg / h, sulfuric acid 65% by weight, nitric acid 5.2
99% mixed acid consisting of 29.8% by weight of water and 29.8% by weight of water.
Continuously pumped into the reactor at a rate of 0 kg / h,
The reaction took place adiabatically. Under these conditions, the benzene / nitric acid molar ratio was 1.4, the linear velocity in the static mixer was 1.05 m / sec, the residence time through the static mixer was 2.6 seconds for the 24th mixer, and 4.8 for the 45th mixer.
Seconds. In the steady state one hour after the start of the reaction, the inlet temperature was 94 ° C and the outlet temperature was 148 ° C. From the analysis results of the acid phase of the reaction liquid sampled by the 24th and 45th static mixers, the nitric acid reaction rates with respect to the charged nitric acid were 73.0% and 99.8%, respectively. Dinitrobenzene (abbreviated as DNB) by-produced from nitrobenzene generated from the analysis result of the 45th organic phase was 300 pp
m, and dinitrophenol (abbreviated as DNP) is 15
The amount of trinitrophenol (abbreviated to TNP) was 200 ppm.

Example 2 A ceramic Noritake static mixer (model CSM-30-) having an inner diameter of 30 mm and having four plate members.
5) The same operation as in Example 1 except that 40 pipes connected in series were used as a conduit, and the feed rates of the mixed acid and Bz were changed to maintain the linear velocity in the static mixer at 1.05 m / sec. Was done. Under these conditions, the residence time through the 40 static mixers is 5.1 seconds. In the steady state one hour after the start of the reaction, the inlet temperature was 9
At 4 ° C the outlet temperature was 140 ° C. 4th, 5th,
From the analysis results of the acid phase of the reaction solution sampled at the 7th and 40th tubes, the nitric acid reaction rates for
31, 32, 33, 90%. The amount of DNB by-produced from nitrobenzene generated from the analysis result of the 40th organic phase was 260 ppm, and the amount of DNP was 1400 pp.
m and TNP was 150 ppm.

Example 3 The mixed acid composition was 65.8% by weight of sulfuric acid, 4.0% by weight of nitric acid,
Water was 30.2% by weight, and the benzene / nitric acid molar ratio was 1.
4. The linear velocity in the static mixer is 1.05 m / s
In order to maintain the temperature at ec, the amount of liquid sent was 3660 kg / h of mixed acid,
The same operation as in Example 2 was performed except that Bz was changed to 254 kg / h. From the analysis result of the acid phase of the reaction solution sampled at the outlet, the nitric acid reaction rate with respect to the charged nitric acid was 95%. From the analysis results of the organic phase, by-product DNB was 300 ppm, DNP was 950 ppm, and TNP was 70 ppm with respect to nitrobenzene produced.

Example 4 In order to set the linear velocity in the static mixer to 0.4 m / sec, the feed rate was 1400 kg / h of mixed acid and Bz97
The same operation as in Example 3 was performed except that the weight was changed to kg / h. Under these conditions, static mixer (40)
Is 13.2 seconds. From the analysis result of the acid phase of the reaction solution sampled at the outlet, the nitric acid reaction rate with respect to the charged nitric acid was 70%. The amount of DNB by-produced from nitrobenzene generated from the analysis results of the organic phase was 2%.
60 ppm, DNP is 700 ppm, TN
P was 50 ppm.

Example 5 The same operation as in Example 3 was performed except that the reaction starting temperature was set at 120 ° C. One hour after steady state, outlet temperature is 155 ° C
Met. From the analysis result of the acid phase of the reaction solution sampled at the outlet, the nitric acid reaction rate with respect to the charged nitric acid was 99.8%. The amount of DNB by-produced from nitrobenzene generated from the analysis result of the organic phase was 945 ppm,
Was 2580 ppm and TNP was 450 ppm.

Example 6 A Noritake static mixer (model CSM-12) made of ceramics having an inner diameter of 12 mm and having eight plate members.
5), followed by a glass lining inner diameter of 12
A series of 12 combinations of hollow tubes of 300 mm length and 300 mm length connected in series was used as a reaction tube.
z at a rate of 51 kg / h, sulfuric acid 65% by weight, nitric acid 5.
5% mixed acid at 99 ° C. consisting of 2% by weight and 29.8% by weight of water
The solution was fed at a rate of 65 kg / h. Under these conditions, the residence time through the static mixer is 2.6 seconds, and the residence time through the hollow tube is 8.8 seconds. From the analysis result of the acid phase of the reaction solution sampled at the outlet, the nitric acid reaction rate with respect to the charged nitric acid was 87%. The amount of DNB by-produced from nitrobenzene generated from the analysis results of the organic phase was 2%.
70 pm, DNP is 1200 ppm, TN
P was 100 ppm.

Example 7 The same operation as in Example 6 was performed except that the length of the glass-lined hollow tube was 800 mm. Under these conditions,
The residence time through the static mixer is 2.6 seconds,
The residence time through the hollow tube is 23.4 seconds. From the analysis result of the acid phase of the reaction solution sampled at the outlet, the nitric acid reaction rate with respect to the charged nitric acid was 99.6%. The amount of DNB by-produced from nitrobenzene generated from the analysis result of the organic phase was 300 ppm, and the amount of DNP was 1500 ppm.
And the TNP was 200 ppm.

Example 8 70% by weight of phosphoric acid (P ₂ O ₅ ), 5.2% by weight of nitric acid, and 24.times. Of chlorobenzene at 24 ° C. at a rate of 144 kg / h.
The same operation as in Example 1 was performed, except that a mixed acid of 8% by weight at 99 ° C. was continuously supplied to the reaction tube by a pump at a rate of 517 kg / h. Under these conditions, chlorobenzene /
The nitric acid molar ratio is 3, the linear velocity in the static mixer is 1.0 m / sec, and the residence time through the static mixer is 4.8 seconds. In the steady state one hour after the start of the reaction, the inlet temperature was 94 ° C and the outlet temperature was 135 ° C.
From the analysis result of the acid phase of the reaction solution sampled at the outlet, the nitric acid reaction rate with respect to the charged nitric acid was 99%, and the isomer ratio (abbreviated as P / O ratio) of paranitrochlorobenzene and orthonitrochlorobenzene was 1.15. Dinitrochlorobenzene (abbreviated as DNCB) by-produced from nitrochlorobenzene generated from the analysis result of the organic phase was 100%.
0 ppm, and chlorophenol (abbreviated as CP) is 4 ppm.
It was 00 ppm.

Example 9 The composition of the mixed acid was as follows: sulfuric acid 62% by weight, nitric acid 5.2% by weight, water 3
The same operation as in Example 8 was performed except that the amount was changed to 2.8% by weight. Under this condition, the rate of nitric acid reaction with respect to the charged nitric acid was 5 based on the analysis result of the acid phase of the reaction solution sampled at the outlet.
At 0%, the P / O ratio was 1.66. DNCB produced as a by-product of nitrochlorobenzene generated from the analysis result of the organic phase was 600 ppm, and CP was 240 ppm.

Example 10 Toluic acid (P ₂₎ was added to toluene at 20 ° C. at a rate of 62 kg / h.
O ₅ ) The same as in Example 1 except that a mixed acid of 70% by weight, 4.5% by weight of nitric acid, and 25.5% by weight of water at 90 ° C. was continuously supplied to the reaction tube by a pump at a rate of 560 kg / h. The operation was performed. Under these conditions, the molar ratio of toluene / nitric acid was 1.68, and the linear velocity in the static mixer was 1.04.
m / sec, the residence time passing through the static mixer (the 45th mixer) is 4.8 seconds. In the steady state one hour after the start of the reaction, the inlet temperature was 82 ° C and the outlet temperature was 130 ° C. From the analysis result of the acid phase of the reaction solution sampled at the outlet, the nitric acid reaction rate with respect to the charged nitric acid was 99%.
DNT (dinitrotoluene) by-produced with respect to mononitrotoluene was 950 ppm, and nitrocresol was 540 ppm. The isomer ratio of mononitrotoluene was orthonitrotoluene: 55.3 (relative ratio), metanitrotoluene: 4.8% (relative ratio), and paranitrotoluene: 39.9% (relative ratio).

Comparative Example 1 A 500 ml autoclave was charged with 268 g of a mixed acid of 63.5% by weight of sulfuric acid, 5.2% by weight of nitric acid, and 31.3% by weight of water, and heated to 99 ° C., followed by benzene at 15 ° C. with nitrogen. 4
g into the autoclave and the system pressure (gauge pressure)
Was adjusted to 3 × 10 ⁵ Pascal, and reacted at a rotation speed of 600 rpm for 300 seconds. Under these conditions, the benzene / nitric acid molar ratio was 1.3 and the temperature of the autoclave reached 140 ° C. From the analysis result of the acid phase of the reaction solution, the nitric acid reaction rate with respect to the charged nitric acid was 99%. The amount of DNB by-produced from nitrobenzene generated from the analysis of the organic phase was 38.
0 ppm, DNP is 1500 ppm, TN
P was 1000 ppm.

Comparative Example 2 70 g of chlorobenzene was heated in an autoclave, and 70% by weight of phosphoric acid (P ₂ O ₅ ), 5.2% by weight of nitric acid, and 24.
The same operation as in Comparative Example 1 was performed except that 250 g of an 8% by weight mixed acid was injected. Under these conditions, the chlorobenzene / nitric acid molar ratio was 3, and the temperature of the autoclave reached 138 ° C. From the analysis result of the acid phase of the reaction solution, the nitric acid reaction rate with respect to the charged nitric acid was 99%. DNCB by-produced from nitrochlorobenzene generated from the analysis of the organic phase
Was 2400 ppm and CP was 1000 ppm.

[0040]

According to the method of the present invention, compared with the conventional method, a simple apparatus, extremely high reaction speed, and safe
The aromatic compound can be nitrated adiabatically, and a high-quality aromatic mononitro compound with few by-products can be produced.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an example of a continuous reaction apparatus used in the present invention, and a part of the apparatus is cut away to show the inside of a mixer conduit.

FIG. 2 is an external view showing several curved plate-like members incorporated in the mixer conduit of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conduit 2 Curved plate member 3 Guide tube A Mixed acid B Aromatic compound

Continuing on the front page (72) Inventor Hiroki Ogaki 30 Asamuta-cho, Omuta-shi, Fukuoka Prefecture, Mitsui-Higashi Pressure Chemical Co., Ltd. (72) Inventor Takafumi Yamaguchi 30 Asamuta-cho, Omuta-shi, Fukuoka Prefecture Mitsui East Pressure Chemical Co., Ltd. (56) References JP-A-7-258173 (JP, A) JP-A-7-278062 (JP, A) JP-A-5-123566 (JP, A) Chemical apparatus, May 1994, pp. 74-78 (58) Fields investigated (Int. Cl. ⁷ , DB name) C07C 205/06 C07C 201/08

Claims (8)

(57) [Claims] 1. A have included a plurality of curved plate-like member a conduit and a plate-like member formed by sequentially continuously arranged brought substantially perpendicular to the edge after the plate-like member which precedes the leading edge to the inside Absent
A reaction tube combined with a hollow tube has a conduit upstream of the reaction.
Position, multiple combinations so that the conduit and hollow tube alternate
A method for producing an aromatic mononitro compound, characterized in that a mixed acid containing nitric acid and an aromatic compound are caused to flow through a reactor that has been reacted. 2. The method of claim 1 , wherein the length of said hollow tube is within said conduit.
The method according to claim 1, wherein the number of plate members to be formed is 40 or less . 3. The method according to claim 1, wherein the material of the curved plate member is ceramics. 4. The method according to claim 1, wherein the reaction temperature in the reactor is 160 ° C. or lower. 5. A mixed acid composition comprising 1 to 10% by weight of nitric acid and 2
3. The process according to claim 1, wherein 0 to 40% by weight, the balance being sulfuric acid and / or phosphoric acid. 6. The linear velocity of the fluid in the reactor is 20 to
The method according to claim 1 or 2, wherein the pressure is 300 cm / sec. 7. The method according to claim 1, wherein the aromatic compound is benzene, toluene, chlorobenzene, naphthalene, or anthraquinone. 8. The reaction mixture discharged from the reactor is separated into an acid phase and an organic phase, and then the acid phase is distilled by flash evaporation to adjust the concentration of the separated acid phase. The method according to claim 1 or 2, wherein the reaction is carried out.