JP2003342206A - 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. <P>SOLUTION: This method for producing the 4-chloro-o-xylene comprises chlorinating o-xylene and affording the 4-chloro-o-xylene. In the method, the following zeolite is used as a catalyst. Zeolite L with ≤1.0 wt.% moisture content, the zeolite L prebaked at ≥200°C or the zeolite L predehydrated at ≥100°C for subsequent use without exposure into the air once, or the like. <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. In addition, Sugit B. Kumar et al. Used KL type zeolite dried at 165 ° C. for 12 hours as a catalyst, and used 1,2 as a solvent.
-It is disclosed that the production ratio of 4-chloroorthoxylene / 3-chloroorthoxylene is increased by utilizing dichloroethane (Journal of Catalysis, 150, p430-433 (1994)).

[0004]

However, even in the conventionally known methods, the selectivity of 4-chloroorthoxylene is still insufficient, and the formation of 3-chloroorthoxylene having a small boiling point difference is suppressed, and 4-chloroorthoxylene is suppressed. There is a need for a method of more selectively synthesizing Increasing the selectivity simplifies the purification process and lowers the fixed cost of the purification process.

Therefore, it is an object to obtain a method for suppressing the production of 3-chloroorthoxylene and selectively synthesizing 4-chloroorthoxylene.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies in order to solve the problems. As a result, in the method of chlorinating orthoxylene to obtain 4-chloroorthoxylene, the water content as a catalyst is The inventors have found that a high selectivity can be achieved by using L-type zeolite in an amount of 1.0% by weight or less, and have reached the present invention.

The present invention mainly has the following constitution in order to solve the above problems. That is, in the method of chlorinating orthoxylene to obtain 4-chloroorthoxylene, L-type zeolite having a water content of 1.0% by weight or less is used as a catalyst. Is. Furthermore, in a method of chlorinating orthoxylene to obtain 4-chloroorthoxylene, as a method of using L-type zeolite having a water content of 1.0% by weight or less, (1) firing at a temperature of 200 ° C. or more And (2) a method of using the L-type zeolite without being exposed to the air even after being dehydrated in advance at a temperature of 100 ° C. or higher.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.
The method for producing 4-chloroorthoxylene of the present invention is a method of chlorinating orthoxylene to obtain 4-chloroorthoxylene, wherein L-type zeolite having a water content of 1.0% by weight or less is used as a catalyst. Characterize.

The L-type zeolite used in the present invention can be easily synthesized by a known method. It is also commercially available and can be purchased from Tosoh Corporation, for example. The L-type zeolite is hydrophilic, and when exposed to the air, it adsorbs water in the air and usually has a water content of 7 to 10%. In the known literature, (Journal of Catalysis, 15
0, p430-433 (1994)) 12 at 165 ° C
Although it is disclosed that the catalyst is activated in a time, even when dehydrated by this method, about 1.4% by weight of water remains in the zeolite. The present inventors have found that the water content is 1.0 by the following method.
It is possible to use L-type zeolite in an amount of not more than 10% by weight as a catalyst for the reaction, and such an L-type zeolite having a low water content is very high in the method of chlorinating orthoxylene to obtain 4-chloroorthoxylene. The inventors have found that they exhibit selectivity and have reached the present invention. (1) After calcining L-type zeolite at 200 ° C. or higher, preferably 400 ° C. or higher, it is cooled while still hot in a desiccator filled with phosphorus pentoxide as a dehydrating agent, and is not exposed to the atmosphere containing water as much as possible. To be introduced into orthoxylene,
(2) L-type zeolite having a water content of more than 1% is introduced into orthoxylene, heated to 100 ° C. or higher to dehydrate water in the zeolite, and used in the reaction as it is without exposing the zeolite to the air. (3) Introduce L-type zeolite into the reaction vessel, heat it to 100 ° C while flowing a dry gas to dehydrate it, and introduce orthoxylene without exposing it to the atmosphere containing water as it is to start the reaction. To do.

The method for measuring the water content of L-type zeolite is shown below. The weight is measured so that the zeolite is not exposed to the air as much as possible, and the weight is defined as W1. The zeolite is 5
Place in an electric furnace at 00 ° C and bake for 3 hours.
Place in a desiccator filled with phosphorus and cool. After cooling to room temperature, the weight is measured so that it is not exposed to the air as much as possible, and the weight is defined as W2. Moisture content is 100 x (W1-
W2) / W1 (%).

Commercially available or as-synthesized L-type zeolites generally contain K ions as cations and about 0.2% by weight Na ions. In the present invention, other cations may be exchanged. Any treatment may be performed on the L-type zeolite.

The amount of L-type zeolite used is usually 0.5 to 60 g per mol of orthoxylene.

The method of the present invention uses orthoxylene as a raw material. As orthoxylene, industrially available orthoxylene can be used without any particular limitation on purity. 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.

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 a liquid phase or a gas phase, but a liquid phase reaction is preferable 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.

In the present invention, it is preferable to add a solvent 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.
Also in the method of the present invention, the selectivity is improved by using the solvent. The reason is not clear.

The solvent used is preferably recovered by distillation or the like and reused from the viewpoint of production cost. Therefore, a compound having a sufficient boiling point difference from the product and a low boiling point 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 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. In particular, dichloroethane such as 1,2-dichloroethane and 1,
Dichloropropane such as 2-dichloropropane and 1,3-dichloropropane is preferable because both activity and selectivity are high.

[0019]

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

Example 1 A reflux tube, a thermometer, a chlorine blowing port, and a sampling port were installed in a 100 ml four-necked flask. 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.

In the above flask, 16.96 ortho-xylene (manufactured by Sigma-Aldrich Japan KK, first-grade reagent).
60 g of 1,2-dichloroethane (manufactured by Sigma-Aldrich Japan Co., Ltd., first grade) per g, KL type zeolite (manufactured by Tosoh Corp. 0.16% by weight Na), which was calcined at 420 ° C. for 1 hour and cooled in a desiccator. 3.39 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. The water content of the KL type zeolite calcined at 420 ° C for 1 hour was 0.1% by weight.

After 3 hours, the conversion of ortho-xylene was 78%.
Thus, the production ratio of 4-chloroorthoxylene / 3-chloroorthoxylene was 8.5.

(Comparative 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.

In the above flask, 16.96 orthoxylene (Sigma Aldrich Japan KK, first-grade reagent).
To g, 60 ml of 1,2-dichloroethane (manufactured by Sigma-Aldrich Japan Co., Ltd., first grade), 3.39 g of KL-type zeolite (manufactured by Tosoh Corporation) that was calcined at 165 ° C. for 12 hours and cooled in a desiccator was added, and nitrogen was added. The 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. The water content of the KL type zeolite calcined at 165 ° C for 12 hours was 1.4% by weight.

After 4 hours, the conversion of ortho-xylene is 80%.
Thus, the production ratio of 4-chloroorthoxylene / 3-chloroorthoxylene was 7.6.

Example 2 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.

In the above flask, 16.96 ortho-xylene (manufactured by Sigma-Aldrich Japan KK, first-grade reagent).
3.39 g of KL type zeolite (manufactured by Tosoh Corp.), which was calcined at 165 ° C. for 12 hours and cooled in a desiccator, was added to g, and heated to 80 ° C. while blowing nitrogen gas from a chlorine gas blowing port. The mixture was heated at 130 ° C for 12 hours to remove the water content in the zeolite. Thereafter, the temperature was lowered to 80 ° C., 60 ml of 1,2-dichloroethane (manufactured by Sigma-Aldrich Japan KK, first grade) was added, and nitrogen gas was changed to chlorine gas to start the reaction. The chlorine gas blowing rate was adjusted to 0.08 mol / hour. 12 at 165 ° C
The water content of the KL-type zeolite calcined for an hour was 1.4% by weight. The water content of the zeolite heated at 130 ° C in xylene has not been exposed to the atmosphere after being heated at 130 ° C, so that the water content of the zeolite during the reaction is lower than 1.4% by weight. Seem.

After 4 hours, the conversion of ortho-xylene is 80%.
Thus, the production ratio of 4-chloroorthoxylene / 3-chloroorthoxylene was 8.2.

[0029]

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 BA81                 4H039 CA52 CD10

Claims (3)

[Claims] 1. A method for obtaining 4-chloroorthoxylene by chlorinating orthoxylene, wherein 4-chloroorthoxylene having a water content of 1.0% by weight or less is used as a catalyst. Manufacturing method. 2. A method for chlorinating orthoxylene using L-type zeolite as a catalyst to obtain 4-chloroorthoxylene, characterized in that L-type zeolite calcined at a temperature of 200 ° C. or higher is used. Method for producing orthoxylene. 3. A method of chlorinating orthoxylene using L-type zeolite as a catalyst to obtain 4-chloroorthoxylene, which has been dehydrated in advance at a temperature of 100 ° C. or higher and then never exposed to the atmosphere. Is used to produce 4-chloroorthoxylene.