JPH01311032A - Transchlorination of aromatic polychloride - Google Patents

Abstract

PURPOSE:To obtain an aromatic compound having high utility value from an aromatic polychloride having low utility value, in high efficiency and yield by using an activated carbon supporting palladium chloride and a rare-earth metal chloride as catalysts. CONSTITUTION:An aromatic polychloride (especially preferably polychlorobenzenes, polychloronaphthalenes, polychlorobipyenyls or polychloropyridines) is transchlorinated to obtain a valuable aromatic compound such as p-dichlorobenzene by using an activated carbon supporting a catalyst consisting of palladium chloride and a rare-earth metal chloride (especially preferably chloride of yttrium, lanthanum or cerium). The same catalyst can be used in the chlorination of benzene ring of an aromatic polychloride to form valuable chlorobenzene and an aromatic compound free from substituted chloride.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a process for transchlorination of aromatic polychlorides. Specifically, activated carbon supporting palladium chloride and rare earth metal chloride is used as a catalyst, and aromatic polychlorides with low utility value to aromatic chlorides with high utility value, or chlorobenzene and aromatic compounds without substituted chlorine are used. Relating to a method of manufacturing.

Conventional technology When aromatic compounds are chlorinated, in addition to the target chloride, polychlorides with little utility value are inevitably produced, and the treatment of these polychlorides with little utility value has become a problem. There is. Conventionally, various proposals have been made for converting such aromatic polychlorides, which have little utility value, into useful chlorides by transchlorination. Transchlorination of aromatic polychlorides includes an isomerization reaction in which chlorine atoms move within the same molecule, a disproportionation reaction in which chlorine atoms move between molecules, and a reaction in which chlorine atoms move to other types of compounds. However, for example, there are many reports on isomerization reactions and disproportionation reactions of aromatic polychlorides using Lewis acids and other catalysts. There have also been reports on reactions that transfer the chlorine atoms of aromatic polychlorides to other types of compounds. A reaction is disclosed in which hydrochloric acid, benzene, chlorobenzene, and isobutyne are obtained by reacting in the gas phase at 350°C. Also, Chemistry Letters (Chemi
Try Letters) 1987. In p. 2051, the present inventor has reported that chlorobenzene can be obtained by reacting orthodichlorobenzene at 400° C. in the gas phase using activated carbon supporting palladium chloride as a catalyst.

Problems to be Solved by the Invention However, none of the isomerization reactions and disproportionation reactions of aromatic polychlorides that have been proposed so far have been industrially useful. There are not many reports on reactions that transfer chlorine atoms to other types of compounds, and the reactions described in the above-mentioned documents have low reaction rates and cannot be used industrially. , it is desired to effectively utilize aromatic polychlorides, which have little utility value.

The present invention was made in view of the above-mentioned current situation, and
The purpose is to provide a transchlorination method for converting aromatic polychlorides with little utility value into aromatic compounds with high utility value.

The present inventors have discovered an extremely highly active catalyst for the isomerization reaction and disproportionation reaction of aromatic polychlorides, which have little utility value, and the chlorination reaction of other types of compounds with aromatic polychlorides,
The present invention has now been completed.

Means for Solving the Problems The structural feature of the present invention lies in the use of activated carbon supporting palladium chloride and rare earth metal chloride as a catalyst in the transchlorination reaction of aromatic polychlorides.

In the present invention, the transchlorination of an aromatic polychloride means an isomerization reaction, a disproportionation reaction, and a chlorination reaction of benzene with an aromatic polychloride.

In the present invention, aromatic polychloride means polychlorobenzenes, polychloronaphthalenes, polychlorobiphenyls, and polychloropyridines.

The catalyst used in the present invention consists of activated carbon supporting palladium chloride and rare earth metal chloride.

This catalyst can be manufactured by a known method.

For example, it can be produced by treating activated carbon with an aqueous solution of palladium chloride, drying, treating with an aqueous solution of rare earth metal chloride, and drying.

Rare earth metal chlorides include yztrium, lanthanum,
It is preferred to use chlorides of cerium and cerium, but chlorides of praseodymium, neodymium, samarium and gadolinium can also be used. These chlorides may be used alone or in a mixture of two or more.

The type of activated carbon is not particularly limited, and any of coconut shell charcoal, coal-based activated carbon, and petroleum-based activated carbon can be used. Furthermore, the activated carbon may be in any shape such as granules, pellets, spheres, and powders.

The concentration of palladium chloride supported on activated carbon is not particularly limited, but is usually set within a range of about 0.01% to 30%, preferably 0.1% to 10%.

Further, the amount of rare earth metal chloride to palladium chloride is not particularly limited, but the molar ratio is usually 0.01 to 100.
, preferably within the range of 0.1 to 10.

In the present invention, transchlorination of aromatic polychloride includes isomerization reaction, disproportionation reaction, and chlorination reaction of benzene with aromatic polychloride as described above. The reaction produces useful para-dichlorobenzene, for example, by converting ortho-dichlorobenzene to baradichlorobenzene. Further, in the disproportionation reaction, for example, useful paradichlorobenzene is produced by converting 1.2.4-)-dichlorobenzene into paradichlorobenzene and tetrachlorobenzene. Furthermore, in the chlorination reaction of benzene with an aromatic polychloride, useful lolobenzene is produced by the reaction between the aromatic polychloride and benzene.

As an example of the transchlorination of an aromatic polychloride of the present invention, the reaction formula for the chlorination reaction of benzene with an aromatic polychloride is illustrated below.

(1) C6H16-, Clll+(n-1) Cb
Ha−+nC6HsCl where n is 2 to 6 Cb Cb H1−−I CI −+ (
0.5n-1) Cs Hs-+0.5 nca H
s C1 Here n is 3 to 6 ■c,,H,,-,,C1,+nCi Hb-nca
Hs C1+C+oHs where n is 1 to 8 (4) CI2H110-111c 1 a +
n C6Ha→nCs Hs C1+C1tl(+
.

Here, n is 1 to 10 (5) Cs H1-sl CI m N+ ncb H
6-nci) Is Cl+cs HsN where n is 1
~5 As is clear from the above reaction formula, the reaction products of the reaction between polychlorobenzenes and benzene are chlorobenzene and dichlorobenzene, and the dichlorobenzene is
It is a mixture of meta-, para-, and ortho-isomers. In the reaction between orthodichlorobenzene and benzene, isomerization of orthodichlorobenzene also occurs. When the molar ratio of benzene to polychlorobenzene is set to 10 or more, chlorobenzene can be selectively produced.

The reaction products of the reaction between polychloronaphthalenes and benzene are chlorobenzene, naphthalene, and chloronaphthalene. When the molar ratio of benzene is set to 10 or more, the production of chloronaphthalene can be suppressed.

The reaction products of the reaction between polychlorobiphenyl and benzene are chlorobenzene, biphenyl, and chlorobiphenyl. When the molar ratio of benzene is 10 or more, the production of chlorobiphenyl can be suppressed.

The reaction products of the reaction between polychloropyridines and benzene are chlorobenzene, pyridine, and chloropyridine. When the molar ratio of benzene is set to 10 or more, the production of chloropyridine can be suppressed.

In the present invention, the transchlorination reaction is preferably carried out in each case in the gas phase.

The simple type of reactor is a fixed bed flow type, but
A fluidized bed type can also be used.

When the reaction is carried out in the gas phase, the space velocity (SV
) is preferably in the range of 0.5 h-' to 10000 h-', more preferably 10 h-' to 1000 h
-' range. In addition, the reaction temperature is 200°C
to 500°C, more preferably 25°C
It is set in the range of 0°C to 450°C.

When aromatic polychloride and benzene are reacted, it is preferable to gasify them in a preheater or the like before introducing them into the reactor, but it is also possible to introduce them in a liquid or slurry form and gasify them in a catalyst layer. If necessary, it may be diluted with an inert gas such as nitrogen.Although the molar ratio of benzene to aromatic polychloride may be set arbitrarily, it is preferably in the range of 1 to 100.

EXAMPLES Next, the present invention will be specifically explained by examples, but the present invention is not limited to the same extent by these examples.

Note that the yields in the following Examples and Comparative Examples were calculated using the following formula.

Yield of C6H, ---r CI,
an integer of 1 to 6, n: the number of benzene chloride salts in the raw material, an integer of 2 to 6, XII: mol% of CbH14-, ICl)
Example 1 Dissolve 1.0 g of palladium chloride in salt 11i1sIIj, add 15Ilj of water to dilute it, and then dissolve granular activated carbon 1.
0 g was added, heated with stirring, and evaporated to dryness.

This is converted into cerium chloride hydrate (CeC1-・7H20)
It was added to an aqueous solution of 2.09 g dissolved in 201" of water, heated with stirring, and evaporated to dryness. The entire amount of the catalyst thus prepared was used in the reaction.

The supported concentration of palladium chloride on activated carbon of the obtained catalyst was 10%, and the molar ratio of cerium chloride to palladium chloride was 1.0.

Quartz fixed bed flow reaction tube (inner diameter 25mm, length 300n
A reaction tube filled with the above catalyst in the center of i+) was heated in an electric furnace, and the temperature of the catalyst layer was maintained at 400°C. Mixture of orthodichlorobenzene (0-DCB) 50 mj and benzene (Ph1100 mj (molar ratio 2.55>
was supplied to the preheater at a flow rate of 10 ij/h, gasified and introduced into the reaction tube. Outflow gas from the reaction tube was introduced into a cooler, liquefied and collected. 6 From 1 hour after the start of the reaction, 2 The composition of the product collected during the hour was PhH57,88,
Chlorobenzene (CB) 28.92, metadichlorobenzene (l-roC3) 2.11, paradichlorobenzene (p-ro CB) 1.34, o-DCB 9.75, trichlorobenzenes (TCB) 0.00 mol% Met.

The yield of CB from o-DCB was 52.3%.

Example 2 Yttrium chloride hydrate (Y
A catalyst was prepared in the same manner as in Example 1, except that CI s .6 H20>1.70r was used.

The composition of the product collected by carrying out the reaction in the same manner as in Example 1 is Phl+ 58.92, CB 27.19, ID
CB 1.71, p-0CR1,09, o-DCB 1
1.09, TCB 0.00 mol%. C.B.
The yield from o-DCB was 49.5%.

Example 3 Lanthanum chloride hydrate (LaCI) was used instead of cerium chloride.
A catalyst was prepared in the same manner as in Example 1, except that s 7 H* O) 2.10ir was used.

The composition of the product collected by carrying out the reaction in the same manner as in Example 1 is PhH59,00, CB2a,95, n-DCB.
C88, D-DCB 1.07, o-DCB 9.
1G, TCB 0.00 mol%. CB o-D
The yield of CB scraps was 54.6%.

Comparative Examples 1 to 5 A catalyst containing no rare earth metal chloride and a catalyst containing another metal chloride instead of the rare earth metal chloride were prepared in the same manner as in Example 1, and using these catalysts, the same procedure as in Example 1 was carried out. The reaction was carried out. The results are shown in Table 1.

Table 1 Note: CI Utagatan Example 4 A reaction was carried out in the same manner as in Example 1, using the entire amount of the catalyst prepared in the same manner as in Example 1, except that 30 g of granular activated carbon was used. However, 1. The reaction temperature (temperature of the catalyst layer) was 360°C. The composition of the product collected between 4th and 5th hours after the start of the reaction was PhH52.71, CB40.14,
m-DCB 2.98, p-DCB 1.92, o-D
CB2.25, TCB 0.00 mol%. C.B.
The yield from o-DCB was 73.7%.

Example 5 A catalyst was prepared in the same manner as in Example 4, and the entire amount was used.

1.2.4-) 10nj! /
The reaction was carried out in the same manner as in Example 4, except that the gas was supplied at a flow rate of h.

The composition of the product is PhH40,61, CB 46.30
, rg-DCB? , 09, p-oca 3.70,
o-DCB 2.30, TCB O, 00 mol%. The yield of CB was 63.9%, and the yield of dichlorobenzenes (DCB) was 36.1%.

Example 6 A catalyst was prepared in the same manner as in Example 4, and the entire amount was used.

1.2.4.5-tetrachlorobenzene (and T) 5.3
The reaction was carried out in the same manner as in Example 5, except that a mixed solution having a composition of 3 mol % and 94.67 mol % benzene was used.

The composition of the product is PhH74,66, CB 18.12
, rg-DCB 3.13, p-DCB 2.
42, 0-ro CB 1゜67, ICB O,00
, TET O, 00 mol%. The yield of CB is 55
．． 7%, and the OCR yield was 44.3%.

Example 7 A catalyst was prepared in the same manner as in Example 4, and the entire amount was used.

The reaction was carried out in the same manner as in Example 5, except that a mixed solution having a composition of 1 mol % hexachlorobenzene and 99 mol % benzene was used.

The composition of the product was PhH 94°07, CB 5.93 mol%. The yield of CB was 100%.

Example 8 A reaction was carried out in the same manner as in Example 4 using a catalyst prepared in the same manner as in Example 1 except that 50 g of granular activated carbon was used. The yield of CB was 75.0%.

Comparative Example 6 A reaction was carried out in the same manner as in Example 8 using a catalyst prepared in the same manner as in Example 1, except that 50 tons of granular activated alumina was used instead of granular activated carbon. The yield of CB is 6.3%
Met.

Example 9 The entire amount of the catalyst prepared in the same manner as in Example 1 except that 30 tons of granular activated carbon was used was filled in the center of a quartz fixed bed flow reaction tube, the reaction tube was heated in an electric furnace, and the catalyst layer was heated. The temperature was maintained at 350°C. Orthodichlorobenzene 101
The gas flowing out from the reaction tube was introduced into a cooler and liquefied and collected. The composition of the product collected during the period was PhHO, 91, CB 20.0
3, DCB31.65, DCB 9.
41, 0-ro CB 11.98, 1, 2.5-I
CB6.23.1, 2.4-TCB 16.13.1,
2.3-TCB 2.14, TET 1.52 mol%.

Example 10 1°2.4 in place of orthodichlorobenzene in Example 9
-) The reaction was carried out in the same manner as in Example 9 except that dichlorobenzene was used. The composition of the product collected between 4 and 5 hours after the start of the reaction was CBO998, n-DCB
9.43, p-oca 6.31, o-DCB 3.
07.1゜3.5-TCB 14.04.1,2.4-
TCB 35.37.1, 2.3-ICB4.07.1
,2,4.5-TET 20.3G ,1,2,3.4
-TET was 3.89, and pentachlorobenzene was 2.54 mol%.

Effects of the Invention As is clear from the comparison between Examples and Comparative Examples, according to the present invention, it is possible to carry out the transchlorination reaction of benzene with an aromatic polychloride in high yield. therefore,
Aromatic chlorides, chlorobenzene, and aromatic compounds with high utility value can be efficiently obtained from aromatic polychlorides with low utility value.

Patent Applicant Kureha Chemical Industry Co., Ltd. Agent Patent Attorney Tsuyoshi Liquidbe Procedural Amendment M (Voluntary) Commissioner of the Patent Office August 12, 1988 Furu 1) Takeshi Moon Address 1-9, Nihonbashi Horidome-cho, Chuo-ku, Tokyo 11@
6. Details of amendment (1) "Aqueous solution" on page 5, line 15 of the specification is corrected to "hydrochloric acid acidic aqueous solution."

■ Correct "praseodymium, neodymium" on page 5, line 20 to "praseodymium, neodymium".

G) "0.5 nc* Hs CI" on page 7, line 16
Correct J to '0.5 nc* H4Cl2J. .

(4) From page 10, line 15 to Suesha's ' Cb Ht
6-61 The yield of Cl m, I = xloo Σ-XI, is converted into the yield of 'C6H+*-0Cl, i = xlOO.

■ Correct "salt" to "chlorine" on page 11, line 3.

(O, page 12, lines 4, 5 and 15, same, 13
3rd line of the same page, 6th line of the 14th page, 15th and 16th lines of the 16th page, and 5th line of the 17th page.
Correct to.

Written amendment to the above procedure (voluntary) □ July 10, 1999 Director General of the Japan Patent Office Yoshi 1) Tsuyoshi Moon 1, Indication of the case 1988 Patent Application No. 137274 2, Name of the invention Trans-chlorine of aromatic polychloride Method 3, Relationship with the case of the person making the amendment Patent applicant representative Shun Kodama Part 4, agent address 1-8-5 Kanda Nishiki-cho, Chiyoda-ku, Tokyo 101 "Detailed description of the invention" in the specification Column 6, Contents of the Amendment Insert the following sentence on a new line after the 9th line of page 17 of the specification.

"Example 11 A catalyst was prepared in the same manner as in Example 4, and the entire amount was used.

Tetrachlorobiphenyl 3.51 mol% and benzene 96
．． A mixture having a composition of 49 mol% was supplied at a flow rate of 10 ml/h. However, the reaction temperature (temperature of the catalyst layer) was 875°C. The composition of the product collected between 5th and 6th hours after the start of the reaction was PhH 88.53, CB 12.30.
DCB O.04, biphenyl 1.09, and monochlorobiphenyl 0.04 mol%. J or more

Claims (3)

[Claims] (1) A method for transchlorinating an aromatic polychloride, which comprises transchlorinating an aromatic polychloride using activated carbon supporting palladium chloride and a rare earth metal chloride as a catalyst. (2) A method for transchlorinating an aromatic polychloride, which comprises reacting the aromatic polychloride with benzene using activated carbon supporting palladium chloride and a rare earth metal chloride as a catalyst. (3) Claim 1, characterized in that the aromatic polychloride is one selected from the group consisting of polychlorobenzenes, polychloronaphthalenes, polychlorobiphenyls, and polychloropyridines. The transchlorination method according to item 1 or 2.