JP3045202B2 - Method for producing paradichlorobenzene - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for selectively producing paradichlorobenzene (hereinafter referred to as P) by chlorinating monochlorobenzene.
DCB).

[0002]

2. Description of the Related Art Disubstituted chlorinated benzene derivatives are industrially important compounds as intermediates for many compounds. Generally, a benzene derivative is prepared by using a Lewis acid such as ferric chloride or antimony chloride as a catalyst. Manufactured by chlorination in the phase. The disubstituted chlorinated benzene derivative has three types of isomers, ortho, meta and para, and the parasubstituted chlorinated benzene derivative is particularly important as a raw material for various organic compounds. Paradichlorobenzene, one of the para-substituted chlorinated benzene derivatives, is an engineering plastic monomer, a pharmaceutical,
It is used as a raw material for pesticides and as a pesticide and insect repellent by itself, and has extremely high industrial value.

[0003] Conventionally, PDCB has been produced by blowing chlorine into benzene or monochlorobenzene in the presence of a Lewis acid catalyst such as ferric chloride. However, the production ratio of the isomer produced by this method is 30 to 40% for the ortho form, 0 to 5% for the meta form, and 60 to 7 for the para form.
It was 5%, and it was difficult to change these formation rates significantly. Also, from ortho-form and meta-form to PD
Since the isomerization reaction to CB is very difficult, many studies have been conducted for the purpose of improving the para-selectivity of the chlorination reaction.

As one of such studies, various attempts have been made to selectively produce PDCB by chlorinating monochlorobenzene using zeolite as a catalyst instead of the conventional Lewis acid catalyst. (1) Chlorination of benzene or monochlorobenzene using L-type zeolite containing a specific amount of potassium as a catalyst to form P
(2) a method for producing DCB by chlorinating benzene in the gas phase in the presence of oxygen using zeolite as a catalyst (JP-A-2-45433); (3) A method for producing PDCB by chlorinating benzene or monochlorobenzene using a zeolite having a specific oxide molar ratio and a powder X-ray diffraction pattern as a catalyst, specifically, ZSM-10 (JP-A-1-246231) No. 1).

It is to be noted that monochlorobenzene is chlorinated to form P
Examples of a method for producing DCB include a method of chlorination using L-type zeolite as a catalyst (Japanese Patent Publication No. 63-12450), and other methods using L-type zeolite with various agents such as a substituted or unsubstituted aliphatic carboxylic acid (eg, 60-19 Kaisho
No. 7632), substituted or unsubstituted metal salts of aliphatic carboxylic acids (JP-A-60-248632), and substituted or unsubstituted aliphatic alcohols (JP-A-61-1728).
No. 37), a lower acylating agent (JP-A-60-1883).
No. 33 discloses that the chlorination of monochlorobenzene using the catalyst treated as described in JP-A No. 33) improves the selectivity of PDCB.

[0006]

As described above, various methods for selectively producing PDCB using a zeolite as a catalyst have been proposed, and it is known that the selectivity of PDCB is improved in the chlorination reaction of monochlorobenzene. Have been. However, further improvement in the para selectivity is desired.

[0007] In the chlorination reaction of monochlorobenzene using zeolite as a catalyst, one factor that inhibits the para-selectivity is that pentachloro, which is formed by the simultaneous radiative chlorination reaction of the nuclear chlorination reaction which is an ion chlorination reaction. It is thought that cyclohexene is in suppressing the ion chlorination reaction of zeolite. Accordingly, the present invention proposes a method for producing PDCB with improved para-selectivity by suppressing the radical chlorination reaction of zeolite. Here, the para selectivity means the ratio of PDCB in the produced dichlorobenzene.

[0008]

SUMMARY OF THE INVENTION In view of the above-mentioned situation, the present inventors have proposed a method for suppressing the radical reaction of zeolite in order to promote the liquid phase chlorination reaction of monochlorobenzene with a zeolite catalyst. As a result of studying the reaction by adding a substance, the presence of 1,2-dichloroethane or bromochloromethane reduces the production of addition chlorinated products such as pentachlorocyclohexene, which is a product of a radical reaction, and reduces PDCB. The selectivity was found to be significantly improved. Further, it has been found that when molecular oxygen coexists, the selectivity of PDCB is further improved and the generation of chlorinated products is suppressed.

The present invention has been made based on such findings. That is, in the present invention, in chlorinating monochlorobenzene in a liquid phase using zeolite as a catalyst, in the presence of 1,2-dichloroethane or bromochloromethane, or 1,2-dichloroethane or bromochloromethane and molecular oxygen A chlorination reaction is carried out in the presence to produce PDCB.

[0010]

The structure of the present invention will be described below in detail. In the present invention, in producing PDCB by chlorination of monochlorobenzene in a liquid phase using zeolite as a catalyst, 1,2-dichloroethane or bromochloromethane, preferably 1,2-dichloroethane or bromochloromethane, is added to a reaction system. Reaction with chlorine gas in the presence of any solvent and molecular oxygen.

When PDCB is produced from monochlorobenzene in the presence of a zeolite catalyst, it may be used in the presence of 1,2-dichloroethane or bromochloromethane, or
When 1,2-dichloroethane or bromochloromethane and molecular oxygen are present, the selectivity of PDCB is improved and the generation of addition chloride is reduced. The effect is particularly large when either a solvent of either 1,2-dichloroethane or bromochloromethane and molecular oxygen coexist.

The zeolite used as a catalyst is L
Type, Y type, mordenite, or zeolites modified by an appropriate method. Particularly, L-type zeolite containing a specific amount of potassium, L-type zeolite ion-exchanged with sodium and barium is preferable. Commercially available L-type zeolites are simple and preferred. The zeolite used for the reaction can be recovered and reused.

The amount of 1,2-dichloroethane or bromochloromethane to be used is 0.01 to 5 volumes, preferably 0.1 to 3 volumes, per 1 volume of monochlorobenzene as a reaction raw material. Further, molecular oxygen is added in an amount of 0.0
It is 5 to 5 moles, preferably 0.1 to 2 moles. Some industrial chlorine gases contain about 1% of oxygen, but this level of oxygen has little effect. As the molecular oxygen, oxygen gas or oxygen gas diluted with an inert gas such as nitrogen may be used. The molecular oxygen may be supplied separately from the chlorine gas, but it is preferable to supply the molecular oxygen by mixing it at a predetermined ratio in advance.

The reaction pressure may be either atmospheric pressure or pressurized. Wei reactants is a liquid phase up to the boiling point temperature below the post-reaction from the reaction temperature is above 50 ° C. at atmospheric pressure or under increased pressure
A lifting temperature, preferably 60 ° C. to 100 ° C. (under pressure). The reaction is based on the degree of salification ( MCB
The average chlorine number was substituted, hereinafter the same) 0.7-1.0, preferably terminates in the scope of 0.75 to 0.9. The type of the chlorination reaction may be either a batch type or a continuous type.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[0016]

[Examples 1-3 and Comparative Example 1] reflux condenser, stirring blade, monochlorobenzene brown glass flask 200ml equipped with a gas inlet tube, _{1,2-dichloroethane,} K 2 O 11% containing L-type zeolite (Tosoh A predetermined amount of TSZ-500KOA manufactured by K.K.) was charged, and chlorine and oxygen gas were introduced at a predetermined flow rate for a predetermined time while stirring at 70 to 75 ° C. The results are shown in Table 1 below. The catalyst used was prepared as follows. 500
ml separable flask to KL-zeolite containing 17.2% as _{K 2} O (TSZ-500KOA, Tosoh
Aqueous solution containing Company Ltd.) 50 g and _NH 4 Cl 4.3 g 3
Then, the mixture was stirred at 90 ° C. for 3 hours. After cooling, the reaction solution was filtered with Toyo Filter Paper No. 5C, washed with ion-exchanged water, freeze-dried, and then baked at 540 ° C. for 3 hours.

[0017]

[Table 1] The meanings of the abbreviations in the table are as follows. The same applies to the following tables. MCB: monochlorobenzene, EDC: 1,2-dichloroethane, m-DCB: metadichlorobenzene, p-D
CB: paradichlorobenzene, o-DCB: orthodichlorobenzene, TCB: trichlorobenzene.

[0018]

Examples 4 to 6 and Comparative Example 1 An L-type zeolite containing 11% of monochlorobenzene, 1,2-dichloroethane and K ₂ O was placed in a 200 ml brown glass flask equipped with a reflux condenser, a stirring blade and a gas inlet tube (Tosoh Corporation). A predetermined amount of TSZ-500KOA (manufactured by K.K.) was charged, and chlorine was introduced at a predetermined flow rate for a predetermined time while stirring at 70 to 75 ° C. The results are shown in Table 2 below. The catalyst used is the same as in Example 1.

[0019]

[Table 2]

[0020]

Examples 7 to 8 and Comparative Example 2 Monochlorobenzene, 1,2-dichloroethane, 1N NaOH-treated L-type zeolite (TSZ: TSZ) was placed in a 200 ml brown glass flask equipped with a reflux condenser, a stirring blade, and a gas inlet tube. A predetermined amount of -500 KOA) was charged, and chlorine and oxygen gas were introduced at a predetermined flow rate for a predetermined time while stirring at 70 to 75 ° C. The results are shown in Table 3 below. The catalyst used was prepared as follows. KL zeolite (TSZ-500KOA containing 17.2% in a separable flask in 1 liter as _{K 2} O, Tosoh
(Manufactured by K.K.) and 500 ml of 1N NaOH aqueous solution were charged and stirred at 90 ° C. for 10 hours. After cooling, Toyo Filter Paper N
The mixture was filtered through o5C, and the cake was washed with ion-exchanged water. After freeze-drying the cake, it was baked at 540 ° C. for 3 hours.

[0021]

[Table 3]

[0022]

Examples 9 to 10 and Comparative Example 3 An L-type zeolite treated with monochlorobenzene, 1,2-dichloroethane and BaCl ₂ (manufactured by Tosoh Corporation) was placed in a 200 ml brown glass flask equipped with a reflux condenser, a stirring blade and a gas inlet tube. A predetermined amount of TSZ-500KOA) was charged, and chlorine and oxygen gas were introduced at a predetermined flow rate for a predetermined time while stirring at 70 to 75 ° C. The results are shown in Table 4 below. The catalyst used was prepared as follows. 500
ml separable flask to KL-zeolite containing 17.2% as _{K 2} O (TSZ-500KOA, Tosoh
Company Ltd.) 20 g and 1 N aqueous solution of barium chloride 200ml
And stirred at 90 ° C. for 1 hour. After cooling, the mixture was filtered with Toyo Filter Paper No. 5C. Put the cake in the reactor again,
200 ml of a specified aqueous barium chloride solution was added, and the mixture was stirred at 90 ° C. for 1 hour. This operation was performed three times in total, and finally, the cake was washed with ion-exchanged water, and the cake was freeze-dried and then baked at 300 ° C. for 4 hours.

[0023]

[Table 4]

[0024]

Examples 11 to 12 and Comparative Example 4 Monochlorobenzene, 1,2-dichloroethane, Y-type zeolite (TSZ-3 manufactured by Tosoh Corporation) were placed in a 200 ml brown glass flask equipped with a reflux condenser, a stirring blade and a gas inlet tube.
10NAA), and chlorine and oxygen gas were introduced at a predetermined flow rate for a predetermined time while stirring at 70 to 75 ° C. The results are shown in Table 5 below.

[0025]

[Table 5]

[0026]

Examples 13 and 14 and Comparative Example 5 Monochlorobenzene, 1,2-dichloroethane, KL zeolite (TSZ-5 manufactured by Tosoh Corporation) were placed in a 200 ml brown glass flask equipped with a reflux condenser, a stirring blade and a gas inlet tube.
00KOA), and chlorine and oxygen gas were introduced at a predetermined flow rate for a predetermined time while stirring at 70 to 75 ° C. The results are shown in Table 6 below.

[0027]

[Table 6]

[0028]

Examples 15 to 16 A predetermined amount of monochlorobenzene, bromochloromethane and KL zeolite (K ₂ O 11%) was charged into a 200 ml brown glass flask equipped with a reflux condenser, a stirring blade and a gas inlet tube.
While stirring at 7 ° C., chlorine and oxygen gas were introduced at a predetermined flow rate for a predetermined time. The results are shown in Table 7 below. The same catalyst as in Example 1 was used.

[0029]

[Table 7]

[0030]

As described above, in the chlorination in the liquid phase in the presence of a zeolite catalyst using monochlorobenzene as a reaction raw material, in the presence of 1,2-dichloroethane or bromochloromethane, or in the presence of 1,2-dichloroethane, Alternatively, by the presence of bromochloromethane and molecular oxygen, remarkable improvement in PDCB selectivity and reduction of added chloride were observed. Therefore, the method of the present invention
Can be obtained with a higher para selectivity and a higher yield by the chlorination reaction of monochlorobenzene, which is suitable as an industrial process for producing PDCB.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-2-45433 (JP, A) JP-A-1-246231 (JP, A) JP-A-62-87536 (JP, A) JP-A-61-1987 172837 (JP, A) JP-A-59-163329 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07C 25/08 C07C 17/12 C07C 17/158

Claims (1)

(57) [Claims] In the chlorination of monochlorobenzene in a liquid phase using a zeolite as a catalyst, in the presence of 1,2-dichloroethane or bromochloromethane,
A method for producing paradichlorobenzene, comprising performing a chlorination reaction using chlorine gas in the presence of 2-dichloroethane or bromochloromethane and molecular oxygen.