JP2003342207A - METHOD FOR PRODUCING 4-CHLORO-o-XYLENE - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing high-purity 4-chloro-o-xylene by which the 4-chloro-o-xylene is selectively produced from 3-chloro-o-xylene when o-xylene is chlorinated to afford the 4-chloro-o-xylene. <P>SOLUTION: This method for producing the 4-chloro-o-xylene comprises chlorinating the o-xylene and affording the 4-chloro-o-xylene. In the method, the moisture content in the o-xylene is ≤100 ppm and used zeolite is reutilized without exposure into the air. Zeolite L is preferred as the zeolite. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing 4-chloroorthoxylene which can be used as a raw material for various organic synthetic chemical substances such as medicines and agricultural chemicals, and a polymer.

[0002]

2. Description of the Related Art 4-Chloroorthoxylene can be obtained by chlorinating orthoxylene in the presence of a Lewis acid. At this time, 3-chloroorthoxylene and α having a small boiling point difference with 4-chloroorthoxylene are used. -Chloroxylene is by-produced.

As a method for selectively obtaining the required 4-chloroorthoxylene, JP-A-3-81234 discloses a method for producing 4-chloroorthoxylene by chlorination of orthoxylene using L-type zeolite as a catalyst. . When a nitro group-containing compound is added as an additive, 4-
It is also disclosed that the production ratio of chloroorthoxylene / 3-chloroorthoxylene is increased. Sugit B. Kumar et al. Also used 1,2-dichloroethane as a solvent to produce 4-chloroorthoxylene /
It is disclosed that the production ratio of 3-chloroorthoxylene is high (Journal of Catalysis, 150).
Vol. Pp. 430-433 (1994)).

[0004]

However, the selectivity of 4-chloroorthoxylene, the reusability of the catalyst, etc. are not sufficient even in the conventionally known methods, and 3-chloroorthoxylene having a high activity and a small boiling point difference is obtained. There is a demand for a method of suppressing the formation of chlorobenzene and selectively synthesizing 4-chloroorthoxylene. If the reaction activity is improved, the fixed cost is reduced, and if the selectivity is increased, the purification process is simplified and the fixed cost of the purification process is reduced. If the catalyst can be reused, the proportional cost can be reduced. In the conventionally known methods, the selectivity and activity of the reaction are disclosed, but the highest recycling of the zeolite catalyst in the raw materials is not disclosed. Reusing the catalyst many times leads to reduction of industrial waste and cost reduction.

Therefore, it is an object to obtain a method for suppressing the production of 3-chloroorthoxylene, selectively synthesizing 4-chloroorthoxylene with high activity, and enhancing the reusability of the catalyst.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies in order to solve the problems, and as a result, in a method of chlorinating orthoxylene using zeolite as a catalyst to obtain 4-chloroorthoxylene, High selectivity can be achieved by controlling the water content of xylene to 100 ppm or less, activity can be achieved by reusing the used zeolite without exposing it to the atmosphere, and reuse without lowering the selectivity, water content of ortho-xylene It was found that the reusability is further improved by setting the rate to 100 ppm or less and reusing the used zeolite without exposing it to the atmosphere, and thus the present invention has been completed.

The present invention has the following constitution in order to solve the above problems. That is, in the method of chlorinating orthoxylene using zeolite as a catalyst to obtain 4-chloroorthoxylene, the water content of orthoxylene is 100 ppm.
Method for producing 4-chloroorthoxylene characterized by the following, method for producing 4-chloroorthoxylene characterized by reusing used zeolite without exposing it to the atmosphere, water content of orthoxylene To 100 ppm or less and to reuse the used zeolite without exposing it to the atmosphere, to provide a method for producing 4-chloroorthoxylene.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.
In the method for producing 4-chloroorthoxylene of the present invention, in the method for chlorinating orthoxylene using zeolite as a catalyst to obtain 4-chloroorthoxylene, the water content of orthoxylene is 100 ppm or less (first invention). , Reuse the used zeolite without exposing it to the atmosphere (the second invention), make the water content of orthoxylene 100 ppm or less, and reuse the used zeolite without exposing it to the atmosphere ( The third invention).

The method of the present invention uses orthoxylene as a raw material. In the second invention, as orthoxylene, industrially available orthoxylene can be used without particular limitation on impurities and the like. The higher the purity, the more preferable, but it is usual that impurities such as para-xylene, meta-xylene, ethylbenzene, and C9 compound are contained in a small amount, and these impurities may be contained. Usually, commercially available orthoxylene contains about 150 ppm of water, but the water content is preferably 100 ppm or less. In the first and third inventions, the water content of orthoxylene is 100 ppm.
It is essential that: The water content can be easily measured with a Karl Fischer water content meter. The method of the present invention is
Zeolite is used as a catalyst. As will be described later, zeolite is usually hydrophilic and has a property of adsorbing water very selectively. Therefore, when the ortho-xylene raw material contains more than 100 ppm of water, water is adsorbed to the zeolite pores and high selectivity cannot be obtained. Further, when the zeolite contains water, hydrogen chloride generated by the chlorination reaction is dissolved in water adsorbed on the zeolite to become hydrochloric acid. As a result, dealumination of the zeolite skeleton is caused and the catalyst life is shortened. In the chlorination of orthoxylene, the zeolite having the highest unit price is not preferable because the production cost becomes high unless the life is long.

The method of the present invention has a water content of 10 as a raw material.
Use 0 ppm or less of orthoxylene. As orthoxylene, industrially available orthoxylene can be used without particular limitation on impurities other than water.
The higher the purity, the more preferable, but it is usual that impurities such as para-xylene, meta-xylene, ethylbenzene, and C9 compound are contained in a small amount, and these impurities may be contained. Ordinary commercial orthoxylene has a water content of 150.
Approximately ppm is included. The method of the present invention uses zeolite as a catalyst. As will be described later, zeolite is usually hydrophilic and has a property of adsorbing water very selectively. Therefore, 1 in the ortho-xylene raw material
If the water content is more than 00 ppm, water will be adsorbed to the zeolite pores and high selectivity cannot be obtained. Also,
When water is contained in zeolite, hydrogen chloride generated by the chlorination reaction is dissolved in water adsorbed on the zeolite and becomes hydrochloric acid. As a result, dealumination of the zeolite skeleton is caused and the catalyst life is shortened. In the chlorination of orthoxylene, the zeolite having the highest unit price is not preferable because the production cost becomes high unless the life is long.

The method for lowering the water content of orthoxylene is not particularly limited, and examples thereof include a method of dehydrating by adding a molecular sieve for dehydration, a method of preheating and removing by distillation, and the like. After removal, it is important not to expose orthoxylene to a moist atmosphere.

The method of the present invention is a chlorination reaction. The chlorinating agent is not particularly limited, and any chlorinating agent such as chlorine gas and sulfuryl chloride can be used,
Price, ease of handling, ease of blowing control,
It is most preferable to use chlorine gas because the reaction pressure can be easily controlled.

The chlorination reaction of the method of the present invention may be in the liquid phase or the gas phase, but the liquid phase reaction is preferred from the viewpoint that the reaction temperature can be set low. If the reaction temperature is too high, side reactions increase. That is, chlorination is achieved by contacting the liquid or vapor of orthoxylene with the chlorinating agent, but it is preferable to contact the liquid orthoxylene with the chlorinating agent. Most preferably, the liquid orthoxylene is brought into contact with chlorine gas by blowing chlorine gas. When blowing, it is preferable to blow while stirring. Further, in order to utilize chlorine efficiently, it is preferable to blow chlorine at a sufficient depth. The reaction may be performed under pressure, atmospheric pressure or reduced pressure, but atmospheric pressure is preferable from the viewpoint of reducing equipment investment.

The reactor used in the method of the present invention is a continuous type,
Either a batch system or a semi-batch system may be used.

The chlorination reaction of the method of the present invention uses zeolite as a catalyst. In the present invention, zeolite is
A crystalline microporous substance, having a uniform pore size of molecular size, crystalline aluminosilicate, crystalline metallosilicate, crystalline metalloaluminosilicate,
It refers to crystalline aluminophosphate, crystalline metalloaluminophosphate, and crystalline silicoaluminophosphate. As used herein, metallosilicate, metalloaluminosilicate, gallium, iron, titanium, boron, a part or all of the aluminum of the aluminosilicate,
It is substituted with a metal other than aluminum, such as cobalt or chromium. Similarly, the metalloaluminophosphate refers to aluminophosphate whose aluminum or phosphorus is partially substituted with another metal.

In the present invention, zeolite means atlas of zeolite structure types (Atlas of Z
eolite Structure types) (WM Meier, DH Olson, Ch. Baerl)
ocher, Zeolites,) 17 (1/2), 1996) (reference 1). A new type of zeolite having a structure not described in the above-mentioned documents is also included in the zeolite of the present invention. However, preferably, L-type zeolite, faujasite-type zeolite, A-type zeolite, MFI-type zeolite, mordenite-type zeolite, β-type zeolite, Ω-type zeolite, which are easily available,
AFI type zeolite, AEL type zeolite, and ATO type zeolite are preferable. Particularly preferred is L-type zeolite in terms of 4-chloroorthoxylene selectivity. The reason why the selectivity of 4-chloroorthoxylene is high when the L-type zeolite is used is not clear at this time.

The L-type zeolite generally contains K ions as cations, but it may contain other ions. The amount of zeolite used is usually 0.5 to 60 g per mol of orthoxylene.

In the present invention, other additives such as a solvent may be added during the chlorination reaction. It is known that the production ratio of 4-chloroorthoxylene / 3-chloroorthoxylene is improved by using dichloroethane as a solvent and KL type zeolite as a catalyst by a conventionally known method, for the reason. Is not clear. Dichloroethane can be preferably used in the present invention. When performing chlorination reaction using zeolite as a catalyst, 1 nm in zeolite structure
It is considered that the reaction proceeds in the smaller pores. In the chlorination reaction in the zeolite pores, the minimum molecular diameter is
It is believed that chloroorthoxylene is selectively produced over 3-chloroorthoxylene. However, the chlorination reaction proceeds without a catalyst, and the chlorination reaction that proceeds without a catalyst has no selectivity. Therefore, the faster the diffusion of ortho-xylene and the produced 4-chloro-ortho-xylene in the zeolite pores, the higher the reaction rate in the zeolite pores,
Both selectivity and activity are improved. It can be presumed that the solvent has a role of promoting adsorption / desorption of the substrate and the reaction substance.

The solvent is preferably collected by distillation and reused. Therefore, a compound having a sufficient boiling point difference from the product and a low temperature is preferable, and a compound having a boiling point of 160 ° C. or lower is preferable. The type of solvent is not particularly limited, but conventionally known chloro-containing compounds and nitro-containing compounds are preferably used. Chloro-containing compounds are preferred because they are more active than nitro-containing compounds. The chloro-containing compound is
It may be aromatic or aliphatic. For example, chlorobenzene, o-, m-, p-dichlorobenzene, chloroform, carbon tetrachloride, chloroethane, dichloroethane, trichloroethane, chloropropane, dichloropropane and the like. A compound having a boiling point of 160 ° C. or lower is preferable from the viewpoint of the subsequent steps and recycling property. Particularly, dichloroethane such as 1,2-dichloroethane and dichloropropane such as 1,2-dichloropropane and 1,3-dichloropropane are preferable because both activity and selectivity are high.

In the second and third aspects of the present invention, the zeolite catalyst used once in the reaction is reused, but it is essential that the zeolite recovered after the reaction is not exposed to the atmosphere.
When exposed to the atmosphere, the selectivity becomes low. Although the reason is not clear, the air contains a large amount of water, and if it is exposed to the air, the zeolite adsorbs the water. It is thought that it is difficult to use.

Specifically, the mixture of the zeolite and the reaction solution after the reaction is separated into a transparent portion and a zeolite-containing portion by natural sedimentation, centrifugal sedimentation or the like. The zeolite-containing portion is reused in the reaction so as not to be exposed to the atmosphere. The reaction liquid may be subjected to the next reaction together with the zeolite. The reaction may be carried out by drying in a dry nitrogen stream or the like without exposing to water as it is by filtering in a moisture-free atmosphere. It is preferable that the zeolite-containing reaction liquid is subjected to the reaction again in a wet state with the reaction liquid. The reason is that the reaction liquid contains a high-boiling substance, and the high-boiling substance may be clogged in the zeolite pores when dried. It is not a particular problem that the high boiling point substance is subjected to the next reaction together with the zeolite, but it is not preferable to solidify it in the zeolite pores. The high-boiling substances due to the chlorination of ortho-xylene are particularly likely to be solidified, and it was difficult to recycle the conventional catalysts, but the present invention made it possible to recycle them.

It is obvious that lowering the water content of the orthoxylene used improves the recyclability of the catalyst.
Moisture contained in ortho-xylene is gradually adsorbed by zeolite and reduces reaction selectivity.

[0023]

EXAMPLES The present invention will be described below with reference to examples.

Example 1 A 100 ml four-necked flask was equipped with a reflux tube, a thermometer, a chlorine injection port, and a sampling port. The waste chlorine gas was exhausted from the upper part of the reflux pipe and trapped with a sodium hydroxide solution. Heating was performed in an oil bath.

The above-mentioned flask was previously charged with a molecular sieve.
16. Ortho-xylene dehydrated at 4 A to a water content of 20 ppm (Sigma Aldrich Japan KK, first-grade reagent) 16.
1,2-dichloroethane (Tokyo Chemical Industry Co., Ltd.) in 96 g
Manufactured by Tohso Co., Ltd., EP) 60 ml, calcined at 400 ° C. for 1 hour and cooled in a desiccator.
39 g was added, and the mixture was heated to 80 ° C. while blowing nitrogen gas through the chlorine gas blowing port. After heating to 80 ° C., nitrogen gas was changed to chlorine gas to start the reaction. The chlorine gas blowing rate was adjusted to 0.08 mol / hour.

After 3 hours, the conversion of ortho-xylene is 78%.
Thus, the production ratio of 4-chloroorthoxylene / 3-chloroorthoxylene was 8.2.

(Comparative Example 1) A reaction was carried out in the same manner as in Example except that orthoxylene was used as a reagent. The water content of the reagent orthoxylene was measured and found to be 138 ppm.

After 3 hours, the conversion of ortho-xylene is 77%.
Thus, the production ratio of 4-chloroorthoxylene / 3-chloroorthoxylene was 7.8.

Example 2 A 100 ml four-necked flask was equipped with a reflux tube, a thermometer, a chlorine blowing port, and a sampling port. The waste chlorine gas was exhausted from the upper part of the reflux pipe and trapped with a sodium hydroxide solution. Heating was performed in an oil bath.

16.96 Ortho-xylene (manufactured by Sigma-Aldrich Japan Co., Ltd .; reagent grade 1 was dehydrated to 20 ppm with molecular sieve 4A) in the flask.
1,2-dichloroethane (manufactured by Tokyo Chemical Industry Co., Ltd.,
EP) 60 ml, KL type zeolite (manufactured by Tosoh Corporation) 3.39 which was calcined at 400 ° C. for 1 hour and cooled in a desiccator.
g was added, and the mixture was heated to 80 ° C. while blowing nitrogen gas through the chlorine gas blowing port. After heating to 80 ° C., nitrogen gas was changed to chlorine gas to start the reaction. The chlorine gas blowing rate was adjusted to 0.08 mol / hour.

After 3 hours, the conversion of ortho-xylene was 87%.
The 4-chloroorthoxylene / 3-chloroorthoxylene production ratio was 8.3. After that, the reaction was continued for 3.5 hours, the supply of chlorine was stopped, the mixture was cooled, and it was allowed to stand. After the zeolite settled to the bottom, the supernatant was removed. Newly, 16.96 g of ortho-xylene (manufactured by Sigma-Aldrich Japan Co., Ltd., which was obtained by dehydrating reagent grade 1 to 20 ppm with molecular sieve 4A), and 60 ml of 1,2-dichloroethane (manufactured by Tokyo Chemical Industry Co., Ltd., EP) In addition, the reaction solution was analyzed by gas chromatography. Orthoxylene: 3-chloroorthoxylene: 4-chloroorthoxylene: α-chloroorthoxylene: dichloroorthoxylene = 77.1: 2.1: 18.8:
It was 0.2: 0.94. Nitrogen gas was heated to 80 ° C. while being blown through the chlorine gas blowing port. After heating to 80 ° C., nitrogen gas was changed to chlorine gas to start the reaction. The chlorine gas blowing rate was adjusted to 0.08 mol / hour.

After 3 hours, the conversion of ortho-xylene was 91%.
The 4-chloroorthoxylene / 3-chloroorthoxylene production ratio was 8.3.

Comparative Example 2 A 100 ml four-necked flask was equipped with a reflux tube, a thermometer, a chlorine blowing port, and a sampling port. The waste chlorine gas was exhausted from the upper part of the reflux pipe and trapped with a sodium hydroxide solution. Heating was performed in an oil bath.

16.96 Ortho-xylene (manufactured by Sigma-Aldrich Japan Co., Ltd .; reagent grade 1 was dehydrated to 20 ppm with molecular sieve 4A) in the above flask.
1,2-dichloroethane (manufactured by Tokyo Chemical Industry Co., Ltd.,
EP) 60 ml, KL type zeolite (manufactured by Tosoh Corporation) 3.39 which was calcined at 400 ° C. for 1 hour and cooled in a desiccator.
g was added, and the mixture was heated to 80 ° C. while blowing nitrogen gas through the chlorine gas blowing port. After heating to 80 ° C., nitrogen gas was changed to chlorine gas to start the reaction. The chlorine gas blowing rate was adjusted to 0.08 mol / hour.

After 3 hours, the conversion of ortho-xylene was 87%.
The 4-chloroorthoxylene / 3-chloroorthoxylene production ratio was 8.3. After that, it reacted for 3.5 hours, stopped the supply of chlorine, cooled, filtered in the atmosphere,
The reaction solution was cut as much as possible.

Ortho-xylene (manufactured by Sigma-Aldrich Japan Co., Ltd., reagent 1 grade 2 with molecular sieve 4A)
16.96 g of water dehydrated to 0 ppm), 60 ml of 1,2-dichloroethane (EP, manufactured by Tokyo Kasei Kogyo Co., Ltd.),
KL-type zeolite (manufactured by Tosoh Corporation) filtered as described above
Was added and the mixture was heated to 80 ° C. while blowing nitrogen gas through the chlorine gas blowing port. After heating to 80 ° C., nitrogen gas was changed to chlorine gas to start the reaction. The chlorine gas blowing rate was adjusted to 0.08 mol / hour.

After 3 hours, the conversion of ortho-xylene was 87%.
The 4-chloroorthoxylene / 3-chloroorthoxylene production ratio was 7.3.

[0038]

INDUSTRIAL APPLICABILITY According to the present invention, 4-chloroorthoxylene can be selectively produced from 3-chloroorthoxylene, and highly pure 4-chloroorthoxylene can be produced.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Naoyuki Uchiyama             1 East of 9 Oemachi, Minato-ku, Nagoya City, Aichi Prefecture             Les Nagoya Office F-term (reference) 4H006 AA02 AC30 BA71 BC30 BD36                       BD52 BE53                 4H039 CA52 CD00

Claims (4)

[Claims] 1. A method for producing 4-chloroorthoxylene, which comprises chlorinating orthoxylene using zeolite as a catalyst to obtain 4-chloroorthoxylene, wherein the water content of orthoxylene is 100 ppm or less. 2. A method for obtaining 4-chloroorthoxylene by chlorinating orthoxylene using zeolite as a catalyst, wherein spent zeolite is reused without being exposed to the atmosphere. Production method. 3. A method for obtaining 4-chloroorthoxylene by chlorinating orthoxylene using zeolite as a catalyst, wherein the water content of orthoxylene is 100 ppm or less and the used zeolite is reused without being exposed to the atmosphere. Of 4-chloroorthoxylene 4. The method for producing 4-chloroorthoxylene according to claim 1, wherein the zeolite is an L-type zeolite.