JP3110531B2 - Method for producing alkyl-substituted aromatic hydrocarbon - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an industrially advantageous method for producing 4,4'-diethylbiphenyl, a raw material for producing 4,4'-biphenyldicarboxylic acid, which is important as a raw material monomer for a heat-resistant polymer material. On how to do it. The 4,4'-diethylbiphenyl can be easily oxidized to give 4,4'-biphenyldicarboxylic acid.

[0002]

2. Description of the Related Art Conventionally, when an ethyl group is introduced into biphenyl, alkylation of biphenyl with ethylene or ethyl halide has been proposed. , 3'-body, 2,
2-substituted such as 4'-form, or 2,3-form, 2,4-form having two ethyl groups in one phenyl nucleus,
For the purpose of the present invention such as the 2,5- and 2,6- isomers, it is inevitable that a large amount of diethyl biphenyl isomer is produced which is not desired.

On the other hand, in the method for producing 4,4'-diethylbiphenyl using a transalkylation reaction, substitution at an adjacent position of an aryl group (that is, position 2 of biphenyl) hardly occurs due to steric hindrance. 2,2'-body, 2,3 '
-, 2,4'-, 2,3-, 2,4-, 2,5
-Body, 2,6-body, etc. are suppressed, and as a result,
There is an advantage that the selectivity of the 4'-form is improved.

[0004] Based on the above idea, transalkylation reactions using polyethylbenzenes or polyethyltoluenes as transalkylating agents have been studied in the past.

[0005] For example, in a method disclosed in Japanese Patent Publication No. 47-15945, a mixture of polyethylbenzenes by-produced when ethylbenzene is produced from benzene and ethylene (hereinafter sometimes referred to as EnBmix in some cases) is used as a transalkylating agent. (Hereinafter sometimes referred to as a TA agent) in the presence of an aluminum chloride catalyst at a reaction temperature of 9
A transalkylation reaction is performed at 0 ° C. with biphenyl (hereinafter sometimes referred to as BP). As a result, when the conversion of biphenyl was 60%, the conversion to monoethylbiphenyl (hereinafter sometimes referred to as EBP in some cases) was 45.4.
%, Conversion to diethyl biphenyl (hereinafter sometimes referred to as DEBP) of 11.2%, selectivity of 2-ethyl biphenyl in monoethyl biphenyl of 1% or less, and 4-ethyl biphenyl (hereinafter sometimes referred to as 4-EBP) was 69%.

Although the publication does not disclose the production ratio of diethyl biphenyl isomer, the selectivity of 4-ethyl biphenyl in monoethyl biphenyl is only 69%. '-Diethylbiphenyl (hereinafter sometimes referred to as 4,4'-DEBP)
Can be estimated to be about 50%. According to the examples in the publication, transalkylation reaction with biphenyl was carried out at a reaction temperature of 120 ° C. in the presence of an aluminum chloride catalyst using diethyltoluene as a TA agent instead of EnBmix, and the conversion of biphenyl was 65. At 6%, the conversion to monoethylbiphenyl was 29.5%, the conversion to diethylbiphenyl was 19.7%, and the selectivity of 4-ethylbiphenyl in monoethylbiphenyl was 50%. .

The publication discloses that the selectivity for 4-position substitution is significantly reduced when the conversion of biphenyl is increased. Therefore, it is necessary to produce 4,4'-diethylbiphenyl on an industrial scale. Increased the conversion of biphenyl,
In addition, it is necessary to increase the 4-position substitution selectivity.

In Japanese Patent Publication No. 49-39667,
A transalkylation reaction with biphenyl is performed at a reaction temperature of 40 ° C. in the presence of an aluminum chloride catalyst using diethyltoluene as a transalkylating agent.

As a result, the conversion of biphenyl is 25%,
Conversion to monoethyl biphenyl 21.3%, conversion to diethyl biphenyl 3.8%, selectivity of 4-ethyl biphenyl in monoethyl biphenyl 90%, conversion of 4,4'-diethyl biphenyl in diethyl biphenyl Selectivity 8
The 4-position substitution selectivity is as high as 1%.

However, according to the method disclosed in the above publication, the conversion of biphenyl is kept as low as 25%, and when the conversion is increased,
It is believed that the 4-position substitution selectivity is significantly reduced. Therefore, it is not preferable as a method for producing 4,4'-diethylbiphenyl on an industrial scale.

It is difficult to selectively and inexpensively produce diethyltoluene used as a transalkylating agent. Even if it is produced by diethylation of toluene, other polyethyltoluenes in addition to diethyltoluene must be produced as a by-product.If diethyltoluene is selectively removed from this mixture of polyethyltoluenes, it is still economical. Not a target.

Therefore, if the mixture of polyethyltoluenes can be used as a reaction raw material, it is very economical and extremely advantageous for industrial production. However, according to experiments conducted by the present inventors, it is difficult to produce efficiently only by using a mixture of polyethyltoluenes as a reaction raw material.

In the method disclosed in JP-A-63-162632, a transalkylation reaction with biphenyl is carried out using a mixture of polyethylbenzenes as a transalkylating agent and a solid acid as a catalyst. For example, when 92.4 parts of biphenyl, 160.9 parts of a mixture of polyethylbenzenes, and 40 parts of silica-alumina as a catalyst are put into a batch reactor and reacted at 250 ° C., the conversion of biphenyl is 64.4%, The results are that the conversion to biphenyl is 44.0%, the conversion to diethyl biphenyl is 12.2%, and the selectivity for 4-ethylbiphenyl in monoethylbiphenyl is 66.4%. Alternatively, in a continuous reactor, using Y-type zeolite as a catalyst,
A 1: 4 (mol) mixture of biphenyl and diethylbenzene was sent to the reactor at LHSV = 1 L / L · H,
When reacted at 250 ° C., the conversion of biphenyl is 87.
4%, 44.0% conversion to monoethylbiphenyl, 33.9% conversion to diethylbiphenyl, 1 conversion to triethylbiphenyl and tetraethylbiphenyl
The result is a selectivity of 2.5% and a selectivity of 4-ethylbiphenyl in monoethylbiphenyl of 48.1%.

[0014] When either silica-alumina or Y-type zeolite is used as a catalyst, 4-ethyl in monoethylbiphenyl is used.
Ethyl biphenyl selectivity is not very high. Although the formation ratio of the diethyl biphenyl isomer is not described, since the selectivity of 4-ethyl biphenyl in monoethyl biphenyl is only 66.4% in the silica-alumina system, 4,4 ′ in diethyl biphenyl is not considered. It can be assumed that the selectivity of -diethylbiphenyl will be around 45% or less.
Although there are many advantages to using a solid acid as a catalyst, it is necessary to improve the substitution position selectivity.

[0015]

As described above, the present invention provides:
It is an object of the present invention to increase the selectivity of 4,4'-diethylbiphenyl in the transalkylation reaction of biphenyl and polyethyltoluenes in the presence of an acid catalyst and to efficiently produce 4,4'-diethylbiphenyl. When the acid catalyst is a Friedel-Crafts catalyst, the conversion of biphenyl is increased while the selectivity of 4,4'-diethylbiphenyl is kept sufficiently high, and the production rate of 4,4'-diethylbiphenyl is significantly increased. The task is to make it work. Further, when the acid catalyst is a solid acid, it is another object to remarkably increase the substitution position selectivity.

The present invention solves these problems, and uses a polyethyltoluene mixture obtained by an industrially inexpensive method as a reaction raw material, and provides a high selectivity and a high production rate of 4,4'-diethylbiphenyl. It is an object of the present invention to provide an industrial production method.

[0017]

That is, the present invention relates to a method for converting biphenyl from a group of ethyl-substituted toluene to a benzene ring.
So that the average number of ethyl groups per one becomes 1.1 to 3.9
And diethyltoluene or triethyltoluene
A transalkylation reaction with a mixture of polyethyltoluenes containing ruene in the presence of an acid catalyst,
This is a method for producing 4'-diethylbiphenyl.

Hereinafter, the production method of the present invention will be described in detail. Examples of the polyethyltoluene (hereinafter sometimes referred to as EnT) used in the present invention include ethyltoluene (hereinafter sometimes referred to as E1T), diethyltoluene (hereinafter sometimes referred to as E2T), and triethyltoluene (hereinafter sometimes referred to as E2T). Occasionally represented as E3T), tetraethyltoluene (hereinafter sometimes referred to as E4T), pentaethyltoluene (hereinafter sometimes represented as E5T).
Ethyl substituents der toluene etc. is, ethyl unsubstituted body
It shall include toluene. These polyethyltoluenes can be easily synthesized by alkylating toluene with ethylene, halogenated ethane, ethanol or the like in the presence of an acid catalyst. Alternatively, one or more polyethyltoluenes can be easily synthesized by a disproportionation reaction or a transalkylation reaction in the presence of an acid catalyst. Industrially, polyethyltoluenes by-produced in the reaction of producing ethyltoluene by ethylation of toluene can also be used.

In the production method of the present invention, polyethyltoluenes as a transalkylating agent are used in a mixture thereof. As a mixture, the average value of the number of ethyl groups substituted by toluene per benzene ring (hereinafter, referred to as the
In some cases, it is important to adjust the mixing ratio of the polyethyltoluenes so that the average ethyl group number and expressed as n *) are 1.1 to 3.9.

The n * of the polyethyltoluene mixture is 1.
Less than 1 is not advantageous because the conversion of biphenyl to diethylbiphenyl is low. If n * of the mixture of polyethyltoluenes is larger than 3.9, the selectivity of 4,4'-diethylbiphenyl in the formed diethylbiphenyl is low, which is not preferable.

Even though a mixture is used, it is not necessary to include all of ethyltoluene, diethyltoluene, triethyltoluene, tetraethyltoluene and pentaethyltoluene among the polyethyltoluenes. However, it is essential to include either or both diethyltoluene and triethyltoluene. Further, diethyl toluene and triethyl toluene may be any positional isomers.

As described above, it is important to use a mixture containing either or both of diethyl toluene and triethyl toluene and having a specific average number of ethyl groups, rather than simply using a mixture of polyethyl toluene. The reason is unknown, but satisfying such requirements enables an efficient reaction.

Such a polyethyltoluene mixture is
It can be easily obtained by a method in which toluene is ethylated with an acid catalyst according to a conventional method. However, the content of ethyltoluene, diethyltoluene, triethyltoluene, tetraethyltoluene, pentaethyltoluene, etc. in the reaction mixture may be considerable depending on the reaction conditions such as the type, amount, reaction temperature, and charging ratio of the acid catalyst in the ethylation. Range. Therefore, if appropriately combined with a separation means such as distillation, and if the acid catalyst and the reaction conditions are set in advance so as to have a predetermined ratio and the toluene is ethylated, a polyethyltoluene mixture conforming to the production method of the present invention can be obtained. It can be easily manufactured.

As the acid catalyst used in the production method of the present invention, any acid catalyst can be used. Specifically, Friedel-Crafts catalysts represented by metal halides such as aluminum trichloride, aluminum tribromide, boron trifluoride, iron trichloride, antimony trichloride, and zinc dichloride;
Or a metal oxide catalyst such as silica-alumina, silica, alumina, chromina, alumina chromina, or a zeolite catalyst such as offretite, X-type zeolite, Y-type zeolite, mordenite, ZSM-5, ZSM-11, or silicotungstic acid , Heteropolyacid catalysts such as phosphotungstic acid, ion exchange resin catalysts such as Amberlyst, hydrogen fluoride, hydrogen fluoride-boron trifluoride, hydrogen fluoride-antimony pentafluoride, chlorosulfonic acid, fluorosulfonic acid, trifluorosulfonic acid Liquid super strong acid catalysts such as dichloromethane, fluorosulfonic acid-antimony pentafluoride, perfluorosulfonic acid resin (trade name: Nafion), or antimony pentafluoride, tantalum pentafluoride, boron trifluoride,
Examples thereof include solid superacid catalysts in which aluminum trichloride, aluminum tribromide and the like are supported on a suitable carrier such as metal oxide, graphite, ion exchange resin and activated carbon. These acid catalysts can be used as a mixture as appropriate.

Particularly preferred catalysts are a Friedel-Crafts catalyst, a zeolite catalyst, a liquid superacid catalyst, a solid superacid catalyst and the like.

In the present invention, the amount of the transalkylating agent used is not particularly limited, but the molar ratio of the total benzene ring to biphenyl ring of the polyethyltoluenes (hereinafter referred to as “the molar ratio”) is used.
EnT / BP) is suitably in the range of 0.1 to 20.0. If the value of EnT / BP is smaller than 0.1, the conversion of biphenyl to diethylbiphenyl is low and not industrial, and if it is larger than 20, 4,4 'from the reaction solution.
The process of separating diethylbiphenyl is not efficient;

In the present transalkylation reaction, the amount of the catalyst used is not particularly limited, but is suitably 0.1 to 50% by weight based on the starting hydrocarbons. The amount of the catalyst can be appropriately selected depending on the type of the acid catalyst used within this range and the value of EnT / BP. If the amount of the catalyst is less than 0.1% by weight, the conversion of biphenyl to diethylbiphenyl is low, which is not industrial. When the amount of the catalyst exceeds 50% by weight, the reaction is not particularly advantageous and is only uneconomical.

The reaction temperature is suitably from 0 to 400 ° C. If the temperature is lower than the reaction temperature range, the reaction rate is low and the reaction is not industrial.On the other hand, if the temperature is high, deethylation, transalkylation of a methyl group, or formation of a large amount of polyethylbiphenyl such as triethylbiphenyl and tetraethylbiphenyl occurs. Are not preferred.

Preferably, it can be selected according to the kind of the acid catalyst used in the above temperature range. For example, 0-300 ° C. for Friedel Crafts catalyst and 100-300 ° C. for zeolite catalyst
300 ° C., 100-400 ° C. for metal oxide catalysts, 0-250 ° C. for liquid super-strong acid catalysts, 0-250 ° C. for solid super-strong acid catalysts
350 ° C. is suitable.

The reaction pressure is not particularly limited as long as the reaction is carried out in a liquid phase, but is usually from normal pressure to 100 kg / cm ^2.
Is appropriate. Even if the reaction pressure exceeds 100 kg / cm ² , it does not adversely affect the reaction, but does not need to be particularly high.

The reaction solvent is not particularly required because the reaction substrate itself can be a reaction solvent. However,
A known inert reaction solvent may be used as appropriate.

The production method of the present invention can be carried out in either a continuous flow reaction mode or a batch reaction mode. In the case of industrial large-scale production, the continuous flow reaction type is suitable, and in the case of small-quantity production, the batch type is suitable.

In the case of production by a continuous flow reaction system, the reaction solution is distilled after the transalkylation reaction, and a fraction lighter than biphenyl mainly consisting of toluene, monoethyltoluene, diethyltoluene and triethyltoluene can be obtained by any method. May be used as a transalkylating agent after ethylation. Of the heavy fractions more than biphenyl, 4,4'-
Some or all of the distillate and bottoms other than diethyl biphenyl may be recycled to the transalkylation step.

After completion of the reaction, the desired product, 4,4'-diethylbiphenyl, can be easily obtained by appropriate separation means, for example, distillation.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments and the like.

Preparation of EnTmix EnTmix used in the reaction was prepared by converting toluene into HY
After alkylating with ethylene in the presence of a type zeolite catalyst (10% by weight based on the aromatic hydrocarbon), a product obtained by removing a heavy component having a boiling point higher than E5T by distillation was used. Further, toluene, E1T and E2T were removed from the thus obtained EnTmix by distillation, if necessary. The reaction temperature of the alkylation was 200 ° C., and the reaction pressure was 20 kg / cm ² with ethylene.

The EnBmix used in the reaction was obtained by alkylating benzene with ethylene and then removing heavy components having a boiling point higher than that of benzene, ethylbenzene and hexaethylbenzene by distillation. The reaction conditions are the same as in the case of the alkylation reaction of toluene.

Example 1 A 200 ml autoclave equipped with a stirrer was charged with 150 mmol of biphenyl and EnTmix (n * = 3.2).
0) 337.5 mmol (the ratio of the number of moles of ethyl groups to the number of moles of biphenyl is hereinafter referred to as ethyl / BP, and in this example, ethyl / BP = 7.2), and 2.31 g of HY-type zeolite. , After purging with nitrogen, stirring 1
The temperature was raised to 85 ° C. After reacting for 18 hours, the reaction solution was analyzed by GLC. Table 1 shows the analysis results.

Comparative Example 1 As a transalkylating agent, EnBmix (n * = 3.20) 337.5 mmol instead of EnTmix
All tests were performed in the same manner as in Example 1 except that (ethyl / BP = 7.2) was used. Table 1 shows the analysis results. However, E2B in the table is diethylbenzene, E3B is triethylbenzene, E4B is tetraethylbenzene,
E5B represents pentaethylbenzene and E6B represents hexaethylbenzene.

COMPARATIVE EXAMPLES 2 to 4 As transalkylating agents, three types of EnTmixes having different n * and each having an equimolar EnT component (Comparative Example 2:
EnTmix consisting of E3T, E4T, E5T and n * = 4.00, Comparative Example 3: EnTmix consisting of toluene, E1T, E2T and n * = 1.00, Comparative Example 4:
EnT composed of E1T and E5T and n * = 3.00
mix) was used in the same manner as in Example 1 except that ethyl / BP was used as 7.2. Table 1 shows the analysis results.

Comparative Examples 5 to 9 As a transalkylating agent, 360 mmol of E3T was used.
(Ethyl / BP = 7.2) (Comparative Example 5), E2T
540 mmol (ethyl / BP = 7.2) (Comparative Example 6), E5T 216 mmol (ethyl / BP =
7.2) (Comparative Example 4), 270 mmol of E4T (et
hyl / BP = 7.2) (Comparative Example 5), E1T108
0 mmol (ethyl / BP = 7.2) (Comparative Example 6)
The test was performed in the same manner as in Example 1 except that each was used. Table 1 shows the analysis results.

Examples 2 to 3 EnTmi containing E1T as transalkylating agent
x (Example 2: n * = 2.47) is 510.1 mmol
(Ethyl / BP = 8.4), EnTmix containing toluene and E1T (Example 3: n * = 1.88) was 67
All tests were performed in the same manner as in Example 1 except that 0.2 mmol (ethyl / BP = 8.4) was used. The results of the analysis are shown in Table 2. In the table, Tol indicates toluene.

Example 4 As a transalkylating agent, EnT used in Example 1 was used.
EnTmix obtained by removing E2T from the mix by distillation
(N * = 3.81) in 330.6 mmol (ethyl
/BP=8.4), except that the test was conducted in the same manner as in Example 1. The analysis results are shown in Table 2.

Examples 5 to 7 As transalkylating agents, three kinds of EnTmixes having different n * and each having an equimolar EnT component (Example 5:
EnTmix consisting of E2T, E3T and E4T and n * = 3.00, Example 6: EnTmix consisting of E2T, E3T and E5T and n * = 3.33, Example 7: E
E consisting of 2T, E4T, and E5T, where n * = 3.67
All tests were performed in the same manner as in Example 1 except that nTmix) was used so that ethyl / BP = 7.2. Table 2 shows the analysis results.

Example 8 A 300 ml three-necked flask was used as a reactor, 2.31 g of aluminum chloride was used as a catalyst, and the reaction temperature was 90 ° C.
The reaction was carried out in the same manner as in Example 1 except that
After completion of the reaction, the reaction solution was washed with water and dried to perform GLC analysis. The conversion of BP was 89.1%, the conversion of BP to EBP was 25.6%, the selectivity of 4-EBP was 90.7%, and the conversion of BP was 90.7%. D
The conversion to EBP was 45.3%, and the selectivity for 4,4'-DEBP was 82.7%.

Example 9 A reaction was carried out in the same manner as in Example 8 except that 2.31 g of trifluoromethanesulfonic acid was used as a catalyst and the reaction temperature was 100 ° C., and the reaction time was 36 hours. After completion of the reaction, the resultant was washed with water and dried, and the reaction solution was analyzed by GLC. As a result, the conversion rate of BP was 55.3%, the conversion rate of BP to EBP was 32.3%,
EBP selectivity 97.4%, conversion of BP to DEBP 2
0.2% and 4,4-DEBP selectivity were 95.5%.

Example 10 As a catalyst, antimony pentafluoride prepared by HY
The reaction was carried out in the same manner as in Example 1, except that 2.31 g of solid superacid supported on zeolite was used.

After completion of the reaction, the reaction solution was washed with water and dried, and the reaction solution was subjected to GLC.
Analysis showed that the conversion of BP was 73.1%,
Conversion to EBP 49.1%, 4-EBP selectivity 8
8.1%, 22.2% conversion of BP to DEBP, 4,
The 4-DEBP selectivity was 69.1%.

(Catalyst preparation method) Granular HY zeolite 2
The reaction tube was filled with 0 g and evacuated at 400 ° C. for 1 hour in a nitrogen stream. After returning to room temperature, antimony pentafluoride was introduced until the pressure reached 1 atm.
Hold for hours. Then, the solid superacid in which antimony pentafluoride was supported on HY zeolite was obtained by maintaining the mixture at 200 ° C. for 2 hours in a nitrogen stream.

[0050]

[Table 1]

[0051]

[Table 2]

[0052]

According to the present invention, 4,4'-diethylbiphenyl can be produced from a polyethyltoluene mixture, which is an economical reaction material, with much higher selectivity than the conventional method. In the presence of a Friedel-Crafts catalyst, 4,4'-diethylbiphenyl can be produced with a high selectivity similar to that of the conventional method and a much higher production rate than the conventional method. Further, according to the present invention, after the transalkylation reaction, the reaction solution is distilled, and a fraction lighter than biphenyl mainly consisting of toluene, monoethyltoluene, diethyltoluene, and triethyltoluene is ethylated by an optional method, and then re-evaporated. It may be used as a transalkylating agent. Of the heavy fractions not less than biphenyl, some or all of the fraction excluding 4,4'-diethylbiphenyl and the bottoms are recycled to the transalkylation step. The biphenyl may be used as the starting material, and substantially all of the ethylenizing agent such as ethylene and the biphenyl can be converted to 4,4'-diethylbiphenyl, so that its industrial significance is extremely high.

Continuation of the front page (51) Int.Cl. ⁷ identification symbol FI C07B 61/00 300 C07B 61/00 300 (58) Field surveyed (Int. Cl. ⁷ , DB name) C07C 6/12 C07C 15/14 CA (STN)

Claims (1)

(57) [Claims] (1) Biphenyl is substituted with ethyl in toluene
Has an average number of ethyl groups per benzene ring of 1.1
~ 3.9, and diethyltoluene
Alternatively, a method for producing 4,4'-diethylbiphenyl , comprising reacting a mixture of polyethyltoluenes containing triethyltoluene with an acid catalyst.