JPH0825968B2 - Continuous process for producing ortho- or para-phenylenediamine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a chemical product. More specifically, it relates to a continuous production method of o- or p-phenylenediamine using a flow tube reactor.

2. Description of the Related Art O- or p-phenylenediamine is a compound useful as an intermediate for dyes, pigments, resins and the like.

O- or p-phenylenediamine is usually produced by subjecting o- or p-dichlorobenzene to an amination reaction in the presence of a copper catalyst.

The production method is usually a batch method, but as a continuous production method, a tank-type continuous method is shown in JP-A-60-193951, and a continuous production method using a perforated plate insertion tower reactor is introduced in JP-A-56-16449. . As an example of using a flow tube reactor as a reaction device, an experimental example in an ammonolysis reaction of nitrochlorobenzenes without a catalyst has been reported.

(BIOS, 1147) Problems to be solved by the invention The method for continuously producing the corresponding o- or p-phenylenediamine from o- or p-dichlorobenzene using a copper catalyst is as described above. Although only Japanese Patent Laid-Open Publication No. Sho is known, all of these methods have the drawback of poor volume efficiency.

Therefore, a method for efficiently and continuously producing the corresponding o- or p-phenylenediamine from o- or p-dichlorobenzene using a copper catalyst has not been established yet.

In view of the above situation, the present inventors have used a copper compound catalyst to convert o- or p-dichlorobenzene into o- or p-dichlorobenzene.
-A thorough study was conducted on the method for efficiently and continuously producing phenylenediamine, including the following problems.
The problem to be solved in continuously producing o- or p-phenylenediamine from o- or p-dichlorobenzene using a copper compound catalyst is a reactor suitable for efficient continuous production. Selection of heterogeneous reaction that may cause clogging in the reactor Method for preparing and using copper-ammonia catalyst suitable for continuous production Method for efficient separation of target compound from reaction product Other (reaction conditions, Material of reactor, etc.)

Means for Solving Problems The present inventors provide the method of the present invention as a method for solving the above-mentioned problems all at once.

That is, the present invention relates to a method for producing o- or p-phenylenediamine from o- or p-dichlorobenzene. (1) An aqueous ammonia solution in which a copper compound catalyst is dissolved in a flow tube reactor and heating to a temperature above its melting point. A step of supplying an amount of o- or p-dichlorobenzene which is less than the solubility in the aqueous ammonia solution to change those chloro groups into amino groups (2) o- or p- extracted from the flow tube reactor An inorganic base was added to the reaction product solution containing phenylenediamine to distill off ammonia and low-boiling fractions, insoluble materials were removed from the residue, and then amine was used for o- or p-
-Providing a continuous process for producing o- or p-phenylenediamine, which comprises the step of extracting phenylenediamine.

 The present invention will be specifically described.

In the present invention, a flow tube type reactor is used as the reactor. Regarding the structure of the flow tube type reactor, a single tube coil type or U tube type is preferable because of its high volume efficiency, but a part or all of the reactor may be a multi-tube type reactor.

In the case of a multi-tube reactor, it is desirable to provide a multi-hole nozzle or a collision plate to prevent the volumetric efficiency from decreasing.

Since the flow tube type reactor is exposed to high chlorine ion concentration under high temperature and high pressure, it is necessary to sufficiently withstand them. Usually, stainless steel such as SUS304 and SUS316 or titanium is used as a material. In particular, titanium is the preferred material.

In the production method of the present invention, the raw material, the catalyst, the product, etc. are in a uniform liquid state in all reaction paths including the raw material charging pipe and the flow pipe reactor so as not to form a heterogeneous reaction system. is necessary. A catalyst prepared by dissolving a monovalent or divalent copper compound in ammonia water is used, and it is considered that the copper compound exists as a copper complex ion in the reaction system. As the copper compound, copper oxide, copper hydroxide or copper halides such as copper chloride and copper bromide are used. Although it is possible to use metallic copper, it is difficult to use metallic copper in terms of dissolution rate. The catalyst usually has an NH ₃ / Cu molar ratio of 20 to 200 mol, more preferably 2 to 30 to 50% ammonia water.
It is prepared by dissolving a copper compound in a molar ratio of 0 to 100. When cuprous halide is used as the copper compound, the cuprous ion may be oxidized to form cupric ion by contacting with air, which may cause precipitation at the reaction temperature. 1 Add sufficient hydrazine or hydrazine hydrate to reduce to copper ions, or add ammonium halide (eg ammonium chloride, ammonium bromide) so that at least equimolar halogen ions are present in the oxidation number of copper. It is better to add it. In the production method of the present invention, the used catalyst is recovered in the form of copper hydroxide or copper oxide, but when using these recovered copper hydroxide, copper oxide or new copper hydroxide, copper oxide, at least the oxidation number of copper It is preferable to add ammonium halides such as ammonium chloride and ammonium bromide so that halogen ions corresponding to If a catalyst is prepared using the recovered copper hydroxide or copper oxide, insoluble matter may be included after the catalyst preparation.In such a case, remove them before use. is necessary.

The o- or p-dichlorobenzene is supplied after being heated above its melting point.

More than solubility in ammonia water at reaction temperature o
-Or p-dichlorobenzene is fed to the reaction tube o
It is necessary to supply o- or p-dichlorobenzene whose solubility in ammonia water at the reaction temperature is lower than that of-or p-dichlorobenzene because it separates oil and impairs the homogeneous reaction. O- or p-dichlorobenzene is supplied so that the molar ratio of NH ₃ / o- or p-dichlorobenzene is 12 to 50 when 30 to 50% aqueous ammonia is used for preparing the catalyst. Is preferred.

The reaction temperature is usually 180 to 240 ° C, preferably 200 to 220 ° C.
The reaction pressure is usually 100 to 200 kg / cm ² , preferably 12
It is 0 to 180 kg / cm ² . The average residence time (reactor solution (l) divided by reaction product solution (l / min)) in the flow tube reactor for raw materials, catalyst, ammonia water, etc. is 30 to 12
It is convenient in operation to design or set the reaction apparatus, the charged amount of raw materials, etc. so that the time is about 0 minutes.

It should be noted that the average residence time in the flow tube reactor was changed to change other reaction conditions such that only one of the two chlorines to be aminated of o- or p-dichlorobenzene was aminated. It is also possible to increase the production amount of p-chloraniline.

Next, a method for taking out the target product from the reaction product solution will be described.

The reaction product solution containing the target substance and others after the reaction in the flow tube reactor is continuously withdrawn to the extraction tank, and copper complex ions present in the reaction product liquid, an amount sufficient to decompose ammonium chloride or more Inorganic base (for example, an aqueous solution of caustic potash, caustic soda, magnesium hydroxide, etc. is continuously added) and heated to ammonia, water, unreacted o- or p-dichlorobenzene, by-product o- or p-
Distill off chloraniline and by-product aniline. The pressure in the extraction tank may be atmospheric pressure, but can be increased to 0.3 to 1.0 kg / cm ² . Pressurization is disadvantageous for the recovery of ammonia, but since the temperature of the extraction tank can be raised, the above-mentioned ammonia, water, unreacted o- or p-dichlorobenzene, and by-products are distilled off. You can shorten the time required for. Usually, it is preferable to adjust the pressure and temperature so that the average residence time is 30 to 100 minutes at 70 to 105 ° C.

Then, the reaction solution is continuously withdrawn from the extraction tank into a separator (tank) to remove copper oxide and copper hydroxide deposited by a filtration method, a sedimentation separation method or the like to obtain an aqueous solution containing o- or p-phenylenediamine. obtain. (The copper oxide and the copper hydroxide separated here are reused for the next catalyst preparation.) Note that the steps after withdrawing from the reactor described above can be carried out batchwise if desired.

Next, the aqueous solution containing o- or p-phenylenediamine is continuously extracted using a countercurrent extractor, or extraction is carried out batchwise or continuously in an ordinary tank to remove water and the extractant. Then, ordinary distillation (including vacuum distillation, vacuum flaker, etc.) is performed to obtain highly pure o- or p-phenylenediamine.

As the extractant, o-toluidine, o-chloroaniline,
Benzene-based amines such as aniline can be used, but the use of aniline gives particularly good results. The amount of extract used is usually 15-70% (weight ratio) of the liquid to be extracted, and the extraction temperature is 40-
It is preferably 60 to 80 ° C, more preferably 100 ° C.

In this way, 99.99% of o- or p-phenylenediamine can be obtained. When the above-mentioned extract is distilled off or p-phenylenediamine is distilled under reduced pressure, it is advantageous to carry out it in the presence of a reducing agent such as sodium sulfide, because the thermal alteration of the target substance can be suppressed. Further, when p-phenylenediamine is produced, 4,4'-diaminodiphenylamine is contained in the residue (distillation residue) of the extract, so that it can be recovered if necessary.

Next, an embodiment of the method of the present invention will be described with reference to a flow chart. (See FIG. 1) 1 is a storage tank for o- or p-dichlorobenzene (which is heated and kept at a temperature higher than the melting point of o- or p-dichlorobenzene) It is sent to the preheater 6 by the pump 3. The amount of o is less than the solubility in an aqueous ammonia solution heated above the melting point and around 200 ° C.
-Or p-Dichlorobenzene is supplied to the flow tube reactor 9 through the mixer 8. On the other hand, 2 is a storage tank for the ammonia aqueous solution of the catalyst, and the ammonia aqueous solution of the catalyst is sent to the preheater 7 at a constant flow rate by the liquid feed pump 4, where it is heated to about 150 ° C. to about 200 ° C. and then passed through the mixer 8. It is supplied to the flow tube reactor 9. As a mixer, titanium in a line mixer, static mixer or pipe,
A Hastelloy ball or net may be inserted, and the essential point is that the melted o- or p-dichlorobenzene and the ammonia solution in which the catalyst is dissolved are uniformly mixed. And the solution of the raw materials, etc., which were uniformly mixed in the mixer, is 150-205 ℃.
And is sent to the reactor. (It is preferable to keep the temperature of the mixer 5 to 20 ° C. lower than the reaction temperature.) After a predetermined average residence time has passed in the flow tube type reactor, the reaction product passes through the extraction valve 10 and the extraction tank 11 Is discharged to. The average residence time in the flow tube reactor is controlled to 30 to 120 minutes by adjusting the supply amounts of the liquid feed pumps 3 and 4. At the same time when a solution such as a raw material to be reacted is fed into the reaction system, nitrogen gas is charged under pressure into the pressure adjusting tank 5, and the pressure at the time of reaction is higher than the autogenous pressure of the ammonia water in the reactor (usually 100 ~200kg / cm ²⁾ it is controlled to. Further, the pressure adjusting tank 5 also has a function of preventing a rapid pressure increase. In order to guarantee a uniform liquid flow of the raw material liquid and the reaction product solution, the discharge valve is controlled by controlling the liquid level of the pressure adjustment tank 5.
It is preferable to adjust 10.

A predetermined amount of the inorganic base aqueous solution is supplied from the inorganic base aqueous solution tank 12 to the reaction product solution guided to the extraction tank 11 via the liquid sending pump 13. The extraction tank is heated to distill off ammonia, water and low boiling fractions.

The distillate is led to a condenser 14 and ammonia is recovered in an ammonia gas absorption tower 15. On the other hand, the reaction liquid from which ammonia, water and low boiling components have been removed is guided to the insoluble matter separator 16 and the precipitated copper oxide and copper hydroxide are recovered. The reaction liquid from which the insoluble matter has been removed is stored in a diamine storage tank 17 as necessary, and then sent to a countercurrent extractor 19 via a pump 18.
A predetermined amount of amine extractant such as aniline is sent from the extractant tank 20 to the countercurrent extractor via the liquid delivery pump 21. The amine extract containing o- or p-phenylenediamine is introduced into the aniline separator 22 to remove the low boiling fraction and the extractant, and then the target compound (o- or p-phenylenediamine) is distilled under reduced pressure. And so on.

In the production method of the present invention, the control of the reaction is easy, so there is no risk of clogging or runaway of the reaction. Since the catalyst is recycled and used, the use efficiency of the catalyst is high, and the obtained o- or p-phenylenediamine Established a technology for efficient continuous production of corresponding phenylenediamine from o- or p-dichlorobenzene, which had many advantages such as high purity, waste liquid per product, and little waste. However, its industrial value is extremely large.

EXAMPLES The method of the present invention will be described in more detail with reference to the following examples. All percentages in the examples are weight percentages.

Example 1 This example was produced using the reactor shown in FIG.

Static mixer (same as 8 and below in Fig. 1) and inner diameter
^Flow tube reactor 9 connected in series consisting of 10 ^mmφ and 20 ^mmφ coils (material titanium, pressure resistance 250 kg / cm ² , internal volume 30
l) was fed with the following homogeneously dissolved ammonia solution A and p-dichlorobenzene heated to 100 ° C. by the feed pumps 3 and 4 at the following charging amounts, and the reaction product solution was extracted from the extraction valve 10. It was extracted into the extraction tank 11. Reaction system pressure is 150k
It was g / cm ² .

The preheaters 6 and 7 on the discharge side of the respective liquid feed pumps were preheated to 200 to 205 ° C. when mixed in the mixer 8. The reactor was kept at 220 ° C. Specific gravity of all reaction solutions
It is estimated to be 0.7 and the average residence time of the reaction solution in the reactor is 6
It was 0 minutes. The composition of the product in the reaction liquid at the reactor outlet is shown below.

P-dichlorobenzene 0.025kg / hr P-chloroaniline 0.158 P-phenylenediamine 1.895 aniline 0.058 4,4'-diaminodiphenylamine 0.124 p-aminophenol etc. % NaOH aqueous solution 1
0.25 kg / hr was added and the mixture was heated to 100 ° C. to remove ammon water and the like distilled out. 21.77 kg / hr (2.7% ammonia water 1
(Including 5.27 kg / hr), the average residence time in the extraction tank 11 was about 1 hour. After collecting the copper hydroxide and copper oxide in the reactor 16 following the extraction tank, the reaction liquid is stored in a storage tank 17 with heat insulation at 65 ° C.
It was stocked at 1 o'clock. The p-phenylenediamine concentration in all reaction solutions was 8.9%. Then, this reaction solution was introduced into a countercurrent extractor 19 and the reaction solution containing 94 kg / hr from the upper stage and the aniline from the lower stage were countercurrently contacted so that the ratio of the p-phenylenediamine-containing reaction solution and the aniline was 2: 1. . The countercurrent extraction device is a perforated plate tower, the tower diameter is 100 mm and the tower height is 5 m. Extraction is 60 ~ 6
It was 5 ° C. The extraction phase contained 14.4% p-phenylenediamine 0.14% p-chloroaniline. Again p
-Dichlorobenzene and p-aminophenol were not included.

The extract was further subjected to a known distillation method to recover and remove aniline, water and p-chloroaniline as low-boiling components and then distilled under reduced pressure to obtain 99.99% p-phenylenediamine. Note that adding a reducing agent such as sodium sulfide during distillation was effective in suppressing thermal deterioration.

The ammonia water distilled from the extraction tank had a concentration of 63% and was additionally absorbed with water. The light fraction was also used for the next reaction of p-phenylenediamine. The separated copper was also used next time.

Example 2 In the same apparatus as in Example 1, the following homogeneously dissolved aqueous ammonia solution B and o-dichlorobenzene were fed,
The reaction was carried out at 180 kg / cm ² and 220 ° C.

The specific gravity of the whole reaction solution was estimated to be 0.7, and the average residence time was 100 minutes.

The composition of the product at the outlet of the reaction tube is shown below.

o-Dichlorobenzene 0.044 kg / hr o-Chloraniline 0.275 〃 o-Phenylenediamine 0.953 〃 Aniline 0.130 〃 Chlorbenzene 0.010 〃 Add 23% caustic potash aqueous solution 11.938 kg / hr to the extraction tank at 105 ° C.
Heated to. Distilled ammonia water and light fraction together
It was 12.117 kg / hr, and 30% ammonia water and oil were separated. The oil produced was 0.166 kg / hr with a composition of 61% o-chloroaniline and 24% o-dichlorobenzene. 11.4
The ammonia concentration was 1% at 3 kg / hr. After passing through the bottom solution, 0.252 kg / hr of cuprous oxide was recovered. (Liquid is pale yellow) Further, 0.174 kg / hr of 15% sodium sulfide aqueous solution was added to the liquid to precipitate residual copper as sulfide. The liquid was collected in a diamine storage tank 17 and kept warm under a nitrogen blanket. The content of o-phenylenediamine in all the solutions was 8%. Example 1
Similarly to the above, aniline was supplied at a rate of 53 kg / hr to 108 kg / hr of the reaction solution, and countercurrent extraction was performed at 60 ° C. The extraction phase contained 13.5% o-phenylenediamine and no o-chloroaniline could be detected.

99.99% of o-phenylenediamine could be obtained by adding sodium sulfide to the aniline extract and distilling off aniline by a known method followed by vacuum flaking.

Example 3 50cc autoclave (mixing autoclave SUS316
100 kg / cm ^{2 in} a reactor equipped with a pressure release valve at the outlet of a reactor connected to a flow tube type reactor with an inner diameter of 3φ (SUS316 pressure resistance 300 kg / cm ² , internal volume 287 ml) from the outlet of 200 kg / cm ² )
Aqueous ammonia solution C, which was uniformly dissolved at room temperature under a pressure of 1, and p-dichlorobenzene which had been heated and dissolved at 100 ° C., were supplied at the following charging amounts to carry out the reaction.

Under these conditions, the temperature will be uniform at 195 to 200 ° C, so the mixing autoclave is set to 200 to 205 ° C and the flow tube reactor is set to 220
It was kept at ℃. The specific gravity of all reaction solutions was estimated to be 0.7, and the average residence time was about 100 minutes. The reaction product liquid had the following composition.

p-Dichlorobenzene trace (%) p-chloroaniline 0.7 p-phenylenediamine 86.1 aniline 2.9 diaminodiphenylamine 5.8 p-aminophenol and others 4.5 This reaction solution was treated in the same manner as in Example 2 9
9.99% p-phenylenediamine was obtained.

Effects of the Invention It has become possible to efficiently produce highly pure o- or p-phenylenediamine continuously from o- or p-dichlorobenzene.

[Brief description of drawings]

FIG. 1 shows an example of a reaction apparatus for continuously producing o- or p-phenylenediamine from o- or p-dichlorobenzene by the production method of the present invention. In Fig. 1 =
The line indicated by and the part surrounded by double lines are high voltage parts. In FIG. 1, 1; o- or p-dichlorobenzene tank 2; catalyst ammonia solution tank 3, 4; liquid feed pump 5; pressure adjusting tank, 6, 7; preheater 8; mixer, 9; flow pipe Type reactor 10; withdrawal valve, 11; withdrawal tank 12; inorganic base aqueous solution tank, 13; liquid feed pump 14; condenser, 15; ammonia gas absorber 16; insoluble matter separator 17; diamine storage tank (stock tank ) 18: Liquid feed pump, 19; Countercurrent extractor 20; Extractant tank, 21; Liquid feed pump 22; Distiller for separating extractant, respectively.

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Claims (1)

[Claims] 1. A method for producing o- or p-phenylenediamine from o- or p-dichlorobenzene (1) Aqueous ammonia solution in which a copper compound catalyst is dissolved in a flow tube reactor and heating above the melting point thereof. A step of supplying an amount of o- or p-dichlorobenzene which is less than the solubility in the aqueous ammonia solution to change those chloro groups into amino groups (2) o- or p- extracted from the flow tube reactor An inorganic base was added to the reaction product solution containing phenylenediamine to distill off ammonia and low-boiling fractions, then insoluble materials were removed from the residue, and then amine was used for o- or p-
-Continuous production method of o- or p-phenylenediamine, comprising the step of extracting phenylenediamine