JPS6391335A - Continuous production of paradichlorobenzene - Google Patents

Abstract

PURPOSE:To obtain the titled compound in high selectivity and efficiently in chlorinating benzene and/or monochlorobenzene by using an L type zeolite catalyst, by making water concentration in the raw material to <= a specific value and carrying out continuous liquid-phase chlorination reaction. CONSTITUTION:In selectively producing parachlorobenzene useful as insecticide, deodorant, etc., by chlorination reaction of benzene and/or monochlorobenzene using L type zeolite, water content in the raw material is suppressed to <=300ppm and continuous liquid-phase chlorination reaction is carried out at preferably 0-200 deg.C, especially 20-150 deg.C to give the aimed compound extremely industrially advantageously while extremely suppressing reduction in activity of the catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for converting dichlorobenpine into 1FjJ Ti by liquid phase chlorination of benzene and/or monochlorobenzene. More specifically, the present invention relates to a method for selectively producing paradichlorobenzene by continuous liquid phase chlorination of benzene and/or monochlorobenzene using an L-type zeolite catalyst.

[Prior Art] Paradichlorobenzene (hereinafter abbreviated as PDCB) is useful as an insect repellent and deodorant, and is an industrially important intermediate in the field of organic synthetic chemistry. Conventionally, PDCB has been produced using benzene or monochlorobenzene (hereinafter referred to as MCB) using a Lewis acid such as ferric chloride or anti-thorn chloride as a catalyst.
It is manufactured by injecting chlorine gas into

However, the 5% ratio of dichlorobenzene produced at this time is paradichlorobenzene, 60-70% metadichlorobenzene, and 0-5% orthodichlorobenzene.
30 to 40%, and a large amount of t1 (orthodichlorobenzene) is produced as a by-product.

Among the three types of isomers, PDCB is the most important industrially and is in high demand. Therefore, many methods for selectively forming PDCB's have been proposed.

As one of the methods, several methods using zeolite as a catalyst have been reported. For example, JP-A-59-1
No. 63329 reports that L-type biolite does not exhibit high PDCB selectivity in a liquid phase halogenation reaction of benzene or halogenated benzene. In addition, in Japanese Patent Application Laid-Open No. 61-189236, L-type zeolite supporting metal salts or Japanese Patent Application No. 60-2471
No. 17 reports that alkali-treated L-type biolite exhibits even higher PDCB selectivity.

These cited examples use a zeolite catalyst in a semi-batch liquid phase reaction, and state that the catalyst can be used repeatedly regardless of the water concentration in the raw materials. However, when considering industrial productivity, a semi-batch type reaction requires a large reactor volume, which causes problems such as temperature distribution and heat removal, so it is desirable to perform a continuous type reaction.

On the other hand, JP-A-57-77631 discloses a gas phase halogenation method using a zeolite catalyst. It has been pointed out that the deterioration is significant.

Also, Tetrahedron Letters (Tetrahedr)
onLetters) Volume 21, pages 3809-3812 (published in 1980), ZSM-5, ZSM-11,
It has been reported that when a gas phase chlorination reaction of benzene is carried out using mordenite, L-type zeolite, and Y-type zeolite as catalysts, L-type zeolite exhibits particularly high PDC83m selectivity. However, the productivity per weight of zeolite catalyst is higher in the liquid phase reaction (furthermore, the liquid phase reaction is more advantageous in terms of needle rhizometry.

That is, when considering industrial productivity, a continuous liquid phase reaction is desired.

[Problems to be Solved by the Invention] It is clear from the prior art that PDCB can be produced with a particularly high selectivity by using an L-type zeolite catalyst in the chlorination reaction of benzene and/or MCB. In the continuous liquid phase reaction, which has the highest productivity, it is expected that there will be a significant decrease in activity, as pointed out in the above-mentioned Japanese Patent Application Laid-open No. 57-77631.

The present inventors have discovered that benzene and/or
Also, when we investigated the continuous liquid phase chlorination reaction of MCB with a particular focus on catalyst life, no decrease in activity was observed in the case of seolide catalysts such as Y-type biolite and mordenite under normal reaction conditions. It has been found that only in the case of the L-type zeolite catalyst, which provides a particularly high PDCB selectivity, the activity decreases significantly.

[Means for Solving the Problems 1] As a result of further detailed study by the present inventors in order to solve these problems, the present inventors found that in order to reduce the activity, We have discovered a completely new fact that trace amounts of water have an extremely large effect. That is, in the chlorination reaction, the raw materials benzene and/or MC
It has become clear that the activity of the L-type biolite catalyst decreases over time when a certain concentration or more of water is present in B.

Normally, benzene and MCB medium which can be handled manually,
150-400ppm and 50-500p respectively
It contains a small amount of pIl water, and when this is used as a raw material, the activity of the L-type zeolite catalyst decreases over time. Therefore, the R
In order to eliminate the influence, the present inventors investigated and found that the water concentration in the raw material benzene and/or MCB was reduced to 30 pp.
It was discovered that the objective could be achieved by suppressing the amount below m.
The present invention has now been completed.

As described above, the present invention provides a method for selectively producing PDCB by a chlorination reaction of benzene and/or MCB using L-type zeolite 1- as a catalyst.
The present invention provides an industrially extremely advantageous method characterized in that a continuous liquid phase chlorination reaction is carried out using benbin and/or MCB, which has been suppressed to less than m, as a raw material.

The present invention will be further explained in detail below.

In the method of the present invention, zeolite is used as a catalyst. Zeolite is usually called a cohesive aluminosilicate, and is composed of SiO4 tetrahedrons and AlO
It is composed of four tetrahedra, but many types are known due to differences in the bonding patterns of each tetrahedron. Zeolides have different crystal structures depending on their type, so they can be identified by powder X-ray analysis.

In the method of the present invention, the zeolite used as a catalyst is L-type zeolite, and its powder X-ray diffraction (copper α
Typical examples of measurement bundles (double lines) are shown in Table 1.

Table 1 5.6 15.8 100 11.2 7.89 5-40 11.8 7.49 10-100 14.8 5.98 10-100 15.3 5.79 10-40 19.4 4 .57 30-80 20.2 4.39 10-10 20.5 4.33 10-10 22.7 3.91 30-120 23.4 3.80 5-40 24.3 3.66 10-10 25.6 3.48 20-80 27.2 3.28 10-60 28.0 3.18 30-120 29.1 3.07 20-80 29.8 3.00 5-40 30.8 2. 91 20-80 33.8 2.65 10-10 34.2 2.62 5-50 L-type zeolite is a type of synthetic zeolite, and can be synthesized by a known method. Specifically, as examples of the method for synthesizing L-type zeolite, Japanese Patent Publication No. 59-73421, Japanese Patent Publication No. 46-35604, and Japanese Patent Publication No. 36-3
Publication No. 675, etc. can be listed. The typical composition of L-type zeolite is 8M2/expressed in molar ratio of oxides.
n0-Al2O3・bSio2a=1.0±0.3.
b=4-8. n represents the valence of the cation M.

In the as-synthesized state, it contains Na ions and/or Na ions as cations.

In the method of the present invention, there is no particular restriction on the cation Δ ion contained in the L-type biolite, and it is sufficient to use as a catalyst a cation containing Na ions and/or ions contained in the L-type biolite. Depending on the situation, it may be possible to use a cation exchanged with another cation. In this case, by a known method using an aqueous solution containing the cation to be exchanged,
Ion exchange treatment may be performed on L-type zeolite.

Furthermore, the L-type zeolite used in the method of the present invention is an L-type zeolite that has been improved to further increase the PDCB selectivity.
Contains type zeolite. For example, JP-A-61-18923
L-type zeolite supporting a metal salt as shown in Publication No. 6, Lτ1 zeolite treated with alkali as shown in Japanese Patent Application No. 60-247117, or JP-A-60-18833
3 Publication, Jil 60-197632 P3 Publication,
Publications No. 60-248631 and No. 61-17283
Examples include L-type zeolite treated with a lower acylating agent, aliphatic carboxylic acid, aliphatic carboxylic acid salt J3, and fatty h% alcohol shown in Japanese Patent No. 7.

In the method of the present invention, there are no particular restrictions on the shape of the catalyst, and it may be used as a powder, but it may also be molded. The molding method may be any conventional method, such as extrusion molding or tablet molding.

Examples include spray drying and granulation methods. When molding, a substance inert to this reaction may be added as a binder or molding aid for the purpose of increasing its mechanical strength. For example, silica, clays, graphite, stearic acid, starch, polyvinyl alcohol, etc. can be added in an amount of 0 to 80% by weight, preferably 2 to 30% by weight.

The catalyst thus obtained is dried if necessary, and then dried under air flow or nitrogen.

Calcination treatment is performed for 10 minutes to 24 hours under the flow of an inert gas such as helium, and the product is used for liquid phase chlorination reaction. The firing temperature is 20
The temperature range may be from 0 to 900°C, preferably from 300 to 8
50℃ is good.

In the method of the present invention, benzene and/or MCB are used as raw materials;
This means that either one of 3 can be used, or benzene can be mixed with MCB recovered from the reaction solution. In the method of the present invention, it is necessary to suppress the water concentration contained in benzene and/or MC[3 used as raw materials to 30 ppm or less. Water concentration can be measured by Karl Fischer method.

There are no particular restrictions on the method of suppressing moisture, and any known dehydration treatment may be performed, such as dehydration using a molecular sieve or the like, or dehydration using distillation.

Examples include a method of dehydrating by reacting with metallic sodium.

As the chlorinating agent, any commonly used chlorinating agent can be used, and chlorine gas may be used.

In the method of the present invention, the liquid phase chlorination reaction is carried out in a continuous manner. Examples of catalysts include fixed bed and fluidized bed.

Any state of suspended bed may be used.

The supply amount of benzene and/or MCB can be expressed as the amount per unit time based on the weight of the zeolite used, and is preferably 1 to 3000 mol//1y-Cat, hr, or 5 to 1000 mol//Kg-Ca[, hr is preferred.

Less than 1 mol/Ig-Cat, hr, sufficient P
DCB production rate + Ct could not be obtained, 3000 mol//
(If it exceeds g-Cat, hr, a sufficient addition rate cannot be obtained.The amount of chlorine gas supplied can also be expressed as the amount per unit time based on the weight of the zeolite used.
~1500 mol/Ig-cat, good hr, 5
~500I101/9-Cat, hr is preferred. 1
mol/KICat, less than hr, sufficient PDCB production rate cannot be obtained, 1500 mol/Ng-Cat,
If the reaction time exceeds hr, the amount of unreacted chlorine gas increases and the reaction is not uniform.

In the method of the present invention, there are no restrictions on the reaction temperature and reaction pressure as long as benzene and/or MCB are in a liquid phase. When the reaction temperature is higher than the boiling point of benzene and/or MCB, the chlorination reaction can be carried out in the liquid phase by increasing the reaction pressure, but the reaction temperature is preferably 0 to 200 ° C. -150 degreeC is more preferable.

Below 0°C, the reaction rate cannot be increased by 200°C.
If the temperature is higher than 0.degree. C., the selectivity of PDCB decreases.

[Brahma effect 1] According to the method of the present invention, when benzene and/or monochlorobenzene is chlorinated using L-type U olide as a catalyst, benzene and By carrying out a continuous liquid-phase thread-forming reaction using monochlorobenzene as a raw material, it is possible to significantly suppress the decline in activity of the L-type zeolite catalyst, and to produce PDCB, which is highly valuable in the coal industry, with high selectivity and efficiency. It can be manufactured as follows.

Therefore, the present invention is extremely significant from an industrial perspective.

[Examples] The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to these Examples.

Note that the conversion rate and selectivity shown in the eggplant examples represent numerical values calculated using the following formula.

Conversion rate @)) - Example 1 Continuous liquid phase chlorination of MCB using L-type zeolite as a catalyst and dehydration with molecular sieves to a water concentration of 20 ppm The reaction was carried out. L-type biolite is published in Japanese Patent Application Publication No. 1983.
Hydrothermal synthesis was carried out under autogenous pressure based on the publication No. 73421.

Next, the slurry was separated by filtration, and the solids were thoroughly washed with water, dried at 110° C. for 15 hours, and calcined at 540° C. for 3 hours under air circulation.

It was confirmed by powder X-ray diffraction using α doublet for copper that the obtained solid powder was L-type zeolite.

Furthermore, acid clay was added as a binder to this L-type zeolite catalyst, and the mixture was granulated by a spray drying granulation method, and then used as a catalyst for a continuous liquid phase chlorination reaction.

The liquid phase chlorination reaction was carried out in a Pyrex double reactor (inner diameter 55 mm) equipped with a stirring device, reflux condenser, and catalyst separator.
m, reactor volume 400 im).

This reactor was filled with 250 g of MC[3 and 20 g of L-type zeolite catalyst, and heated using an oil bath. Then, while stirring the reaction mixture, chlorine gas was continuously supplied to the reactor through a blowing pipe using a constant M pump. Note that MC[3 was used after dehydrating a reagent (Kishida Kagaku) with a molecular sieve, and the water concentration measured with a Karl Fischer moisture meter was 20 ppm.

Reaction temperature 100°C, MCB supply amount 117.8no I
/Iy-Cat, hr, chlorine supply fn 58, 9
mol/to! I-Cat, hr. The product was continuously withdrawn from the reactor and analyzed by gas chromatography.

Figure 1 shows the change in the MCB conversion rate over time.The MCB conversion rate was 49.3% at the start of the reaction and 48% even after 100 hours
．． 7%, and almost no decrease in activity was observed.

During this period, the PDCB selectivity remained constant at 87.5% during the reaction.

Comparative Example 1 A liquid phase chlorination reaction was carried out under exactly the same catalyst 1 reaction conditions as in Example 1, except that the reagent was used as it was as the raw material MCB. The moisture concentration of the raw material MCB measured with a Karl Fischer moisture meter was i7 (3 ppm).

Figure 1 shows the change in MCB conversion over time. The MCB conversion was 49.2% at the start of the reaction, but decreased to 37.1% after 100 hours. During this period, the PDCB selectivity remained constant at 87.5%.

Comparative Example 2 Catalyst 9 which was completely the same as Example 1 except that the raw material MCB used was one whose moisture content was adjusted to 50 ppm.
A liquid phase chlorination reaction was carried out under the reaction conditions.

The MCB conversion rate was 49.2% at the start of the reaction, and decreased to 43.1% after 100 hours.

Example 2 The L-type zeolite catalyst prepared in Example 1 was used in JP-A-61-
Based on Japanese Patent No. 189236, an improved type zeolite catalyst carrying 10% by weight of sodium chloride was prepared by evaporation to dryness.

Using this improved zeolite catalyst, a continuous liquid phase chlorination reaction of benzene was carried out using the same reactor 9 reaction method as in Example 1, using penpin dehydrated with a molecular sieve as a raw material.

Reaction temperature 80°C, benzene supply ff1143.5mo
l/N9-Cat, hr, chlorine supply Li! 143
, 5 mol//(g-Cat, hr.) The water concentration of the raw benzene measured with a Karl Fischer moisture meter was 19.31111 m.The benzene conversion rate was 79.1% at the start of the reaction. , even after 20 hours, 78.
7%, and almost no decrease in activity was observed. Furthermore, the selectivity of loose bodies in dichlorobenzene was approximately constant at 92.0%.

Comparative Example 3 Using the improved biolite catalyst prepared in Example 2,
Except for using a commercially available product as raw material benzene.
A continuous liquid phase hydrogenation reaction of benzene was carried out under reaction conditions similar to Ai Example 3. In addition, the water concentration of raw benzene measured with a Karl Fischer moisture meter is 2401)D
It was I. The benzene conversion rate was 79.3% at the start of the reaction.
However, after 20 hours, it decreased to 75.2%.

Example 3 The L-type zeolite powder prepared in Example 1 was used in a patent application filed in 1980-
An improved alkali-treated zeolite was prepared based on Japanese Patent No. 247117. Alkali treatment is al11
4.3 at 90°C using an aqueous sodium hydroxide solution.
Time went. This improved type zeolite was granulated by a spray drying granulation method.

A continuous liquid phase chlorination reaction of MCB was carried out in the same manner as in Example 1 using the granulated improved zeolite catalyst 20Q with a water concentration of 201)I)m.

The MCl3 conversion rate was 49.0 during 50 hours from the start of the reaction.
It remained almost constant at 2%. Also, during this time 1] D C8
The selectivity was as high as 92.1%.

Comparative Example 4 Using the improved zeolite catalyst 20a prepared in Example 3, a continuous liquid solution of MCB was prepared in the same manner as in Example 3 except that MCB with a moisture content of 1761) was used as the raw material. A phase chlorination reaction was carried out.: The MCB conversion rate was 49.2% at the start of the reaction, but after 50 hours it was 49.2%.
It decreased to 5.2%.

Comparative Example 5.6 Commercially available Na-mordenite (trade name Zeolon 10ONa
, manufactured by Two-Tone) by adding acid clay as a binder,
A continuous liquid phase chlorination reaction of MC [3 with a water content of 176 ppm and 20 Fllll] was carried out using 20q of the granulated product by the spray drying granulation method as a catalyst under the same reaction conditions in the reactor 1 as in Example 1. did. Moisture m degree is 176 Dp
In both cases of II and 20 ppm, the MCB conversion was constant at approximately 49.6% for 100 hours from the start of the reaction, but the PDCB selectivity was 69.8%. As described above, when moranite is used as a catalyst, there is no effect of moisture in the raw material.

Comparative Example 7.8 Acid clay was added as a binder to commercially available Na-Y type zeolite (manufactured by Toyo Kaida Kogyo Co., Ltd.), and 20 g of the granulated product was used as a catalyst to adjust the water concentration. is 176p
A continuous liquid phase chlorination reaction of pm and 20 ppm MCB was carried out under the same reactor 1 ash reaction conditions as in Example 1.

At both water concentrations of 176 pl)m and 20 ppm, the MC[3 conversion rate was constant at approximately 49.7% for 100 hours from the start of the reaction, but the PDCBm selectivity was 79.5%. there were. When a Y-type zeolite catalyst is used, no influence of water in the raw material r1 is observed.

4. Brief explanation of Figure 1 Figure 1 is a graph showing changes in MCB conversion rate over time in Example 1 of the present invention and Comparative Example 1.

Claims (1)

[Claims] In a method for producing paradichlorobenzene by chlorination reaction of benzene and/or monochlorobenzene using an L-type zeolite catalyst, a continuous liquid phase chlorination reaction is performed using benzene and/or monochlorobenzene with a water concentration of 30 ppm or less as a raw material. A method for producing paradichlorobenzene, characterized by: