JPH06166642A - Production of alkyl-substituted aromatic hydrocarbon - Google Patents

Abstract

PURPOSE:To efficiently produce a 4,4'-dialkylbiphenyl in high selectivity of alkylation at the 4-position in trans-alkylation reaction of a 4-alkylbiphenyl and polyethyltoluene in the presence of a Friedel-Crafts catalyst. CONSTITUTION:A 4-alkylbiphenyl is reacted with a polyethyltoluene mixture containing diethyltoluene or triethyltoluene, having the average number of ethyl groups per benzene ring satisfying the following formula: 1.1<=n<=3.9 (n is average number of ethyl group per benzene ring) in the presence of a Friedel-Crafts catalyst under a condition wherein the ratio of the number of mols of ethyl group of the polyethyltoluene mixture and the total of the number of mols of benzene ring of the polyethyltoluene mixture and the number of mols of biphenyl satisfies the following formula: 1.0<=Et/(Bz+Bp) (Et is the number of mols of ethyl group, Bz is the number of mols of benzene ring of polyethyltoluene mixture and Bp is the number of mols of biphenyl) to produce a 4,4'-dialkylbiphenyl.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to 4,4'-diethylbiphenyl and other 4,4'-, which are raw materials for producing 4,4'-biphenyldicarboxylic acid, which is an important raw material monomer for heat-resistant polymer materials. The present invention relates to a method for industrially producing a dialkylbiphenyl. The 4,4'-dialkylbiphenyl can be easily produced into 4,4'-biphenyldicarboxylic acid by oxidizing the 4,4'-dialkylbiphenyl by a conventional method.

[0002]

2. Description of the Related Art When introducing an ethyl group into a biphenyl ring, it has been proposed to carry out ethylation with ethylene or ethyl halide. However, this method cannot avoid the production of a large amount of undesired isomers such as 2-alkylbiphenyl.

On the other hand, in the transalkylation reaction, substitution at the adjacent position of the aryl group or the alkyl group is unlikely to occur due to steric hindrance, and the 4-position alkylation selectivity is improved. Therefore, benzene having at least one ethyl group (hereinafter sometimes referred to as polyethylbenzene or EnB) or toluene having at least one ethyl group (hereinafter sometimes referred to as polyethyltoluene or EnT)
Has been conventionally studied.

For example, in the method disclosed in JP-B-47-15945, a polyalkylbenzene mixture (hereinafter sometimes referred to as EnBmix) produced as a by-product when ethylbenzene is produced from benzene and ethylene is used as a transalkylating agent ( Hereinafter referred to as TA agent in some cases)
Used in the presence of aluminum chloride catalyst, reaction temperature 90 ℃
And transphenylation reaction with biphenyl (hereinafter sometimes referred to as BP). As a result, when the conversion rate of BP was 60%, the conversion rate to monoethylbiphenyl (hereinafter, sometimes referred to as EBP) was 45.4%, and the conversion rate to diethylbiphenyl (hereinafter, sometimes referred to as DEBP) was 11%. At 0.2%, the selectivity of 2-ethylbiphenyl in EBP was 1% or less, and the selectivity of 4-ethylbiphenyl (hereinafter sometimes referred to as 4-EBP) was 69%.

Further, according to the embodiment of the publication, EnBm
Diethyltoluene was used as a TA agent instead of ix in the presence of an aluminum chloride catalyst to perform a transalkylation reaction with BP at a reaction temperature of 120 ° C., and the conversion rate of BP was 6
When 5.6%, conversion rate to EBP 29.5%, DEBP
The conversion rate to 1 is 99.7% and the selectivity of 4-EBP in EBP is 50%.

According to the publication, when the conversion rate of BP increases, 4-
Since it has been shown that the position alkylation selectivity is remarkably reduced, a method for producing 4,4'-dialkylbiphenyl (hereinafter sometimes referred to as 4,4'-DABP) on an industrial scale is Not satisfactory.

Further, in Japanese Patent Publication No. 49-39667,
Using diethyltoluene as a TA agent, a transalkylation reaction is carried out with BP at a reaction temperature of 40 ° C. in the presence of an aluminum chloride catalyst.

As a result, the conversion rate of BP was 25%, and EB
Conversion to P 21.3%, conversion to DEBP 3.8
%, The selectivity of 4-EBP in EBP is 90%, and the 4-position alkylation selectivity is high.

However, even in the method of the above publication, the conversion rate of BP is kept as low as 25%, and when the conversion rate is increased, 4-
It is considered that the degree of alkylation selectivity is significantly lowered. Therefore, it is not preferable as a method for producing 4,4'-DABP on an industrial scale.

In the above two publications, it is difficult to selectively and inexpensively produce diethyltoluene used as a TA agent. Even if it is produced by diethylation of toluene, other EnT of diethyltoluene is unavoidable as a by-product, and it is still not economical to selectively take out diethyltoluene from this mixture of EnT.

Therefore, if the mixture of EnT itself can be used as the reaction raw material, it will be economical and extremely advantageous for industrial production. However, according to the experiments conducted by the present inventors, it is difficult to perform efficient production simply by using a mixture of EnT as a reaction raw material.

On the other hand, in the method disclosed in JP-A-63-162632, EnBmix is used as a TA agent,
A transalkylation reaction is carried out with BP using a solid acid as a catalyst. For example, BP92.4 part, EnB
mix 160.9 parts, silica-alumina 40 as a catalyst
Part was put into a batch type reactor and reacted at 250 ° C., conversion rate of BP was 64.4%, conversion rate to EBP was 4
The results are 4.0%, conversion to DEBP 12.2%, and 4-EBP selectivity in EBP 66.4%.

Alternatively, in a continuous reactor, using Y-type zeolite as a catalyst, BP and diethylbenzene are mixed in a ratio of 1: 4.
When the (mol) mixed solution was fed into the reactor at LHSV = 1 L / L · H and reacted at 250 ° C., the conversion rate of BP was 87.4%, the conversion rate to EBP was 44.0%, and the DEBP was DEBP.
The conversion rate is 33.9%, the conversion rate to triethylbiphenyl and tetraethylbiphenyl is 12.5%, and the selectivity of 4-EBP in EBP is 48.1%.

The selectivity of 4-EBP in EBP is not so high whether silica-alumina or Y-type zeolite is used as a catalyst. When a solid acid is used as a catalyst, it is industrially superior to homogeneous acid catalysts such as the Friedel-Crafts catalyst because it does not require an acid neutralization step, but the regioselectivity of alkylation can never be satisfied. is not.

[0015]

As described above, the present invention is
4-alkylbiphenyl (hereinafter, sometimes 4-ABP
In the transalkylation reaction of EnT with
It is an object of the present invention to increase the 4-position alkylation selectivity in the presence of a Friedel-Crafts catalyst and to provide an efficient method for producing 4,4'-DABP.

That is, the present invention solves the above-mentioned problems and uses a polyethyltoluene mixture (hereinafter, sometimes referred to as EnTmix) obtained by an industrially inexpensive method as a reaction raw material, with high selectivity and high production. Rate of 4,4'-D
It is intended to provide an industrial production method of ABP.

[0017]

That is, the present invention provides 4-ABP containing diethyltoluene or triethyltoluene in the presence of a Friedel-Crafts catalyst, and n is 1.1.
EnTmix of ~ 3.9 and Et / (Bz + Bp)
Is a transalkylation reaction under a condition of 1.0 or more, and is a method for producing 4,4′-DABP.

Here, n represents the average number of ethyl groups per one benzene ring, Et is the number of ethyl group moles in the polyethyltoluene mixture, Bz is the number of benzene ring moles in the polyethyltoluene mixture, and Bp is 4-. Represents the number of biphenyl ring moles of alkylbiphenyl.

The manufacturing method of the present invention will be described in detail below. 4-ABP used in the present invention is 4
-Methylbiphenyl (hereinafter sometimes referred to as 4-MBP) or 4-EBP. These can be used alone or as a mixture. When 4-MBP is used as a starting material, 4-ethyl-4'-methylbiphenyl (hereinafter sometimes referred to as 4,4'-EMBP) is used as 4-EBP.
4,4'-diethylbiphenyl (hereinafter,
In some cases 4,4'-DEBP) is produced respectively.

EnT used in the present invention is toluene (hereinafter sometimes referred to as TOL) and an ethylated product of TOL, that is, TOL, ethyltoluene (hereinafter sometimes referred to as E1T), diethyltoluene (hereinafter referred to as In some cases, E2T), triethyltoluene (hereinafter sometimes referred to as E3T), tetraethyltoluene (hereinafter sometimes referred to as E4T), pentaethyltoluene (hereinafter sometimes referred to as E5T).
These EnTs may be any position isomer.

These EnTs can be easily synthesized by alkylating TOL with ethylene, halogenated ethane, ethanol or the like in the presence of an acid catalyst. Alternatively, one or more kinds of EnT can be easily synthesized by a disproportionation reaction or a transalkylation reaction in the presence of an acid catalyst.
Industrially, EnT which is a by-product of the ethyltoluene production reaction by ethylation of TOL can also be used.

In the production method of the present invention, EnT as a TA agent is used in a mixture thereof. As for the mixture, it is important to adjust the mixing ratio of EnT so that n is 1.1 to 3.9.

If n of EnTmix is less than 1.1, 4-
Dialkylbiphenyl of ABP (hereinafter, DA in some cases
It is not industrial because the conversion rate to BP) is low, and when n of EnTmix exceeds 3.9, the selectivity of 4,4′-DABP in the produced DABP is low.
Neither is preferable.

Even if a mixture is used, the EnT
Out of TOL, E1T, E2T, E3T, E4T, E5
It is not necessary to include all of T. However, it is essential to include either or both E2T and E3T.

As mentioned above, it is imperative to use a specific nTnMix containing either or both of E2T and E3T and not simply using a mixture of EnTs. Although the reason is unknown, satisfying such requirements enables an efficient reaction.

Such EnTmix can be easily obtained by a method of ethylating TOL in the presence of an acid catalyst according to a conventional method. However, depending on the reaction conditions such as the type, amount, reaction temperature and reaction pressure of the acid catalyst during the ethylation, E
TOL, E1T, E2T, E3T, E4 in nTmix
The contents of T and E5T change within a considerable range. Therefore, by properly combining with a separation means such as distillation, and setting the reaction conditions so as to have a predetermined ratio in advance and ethylating TOL, EnTmix conforming to the production method of the present invention can be easily produced. it can.

In the present invention, the amount of the TA agent used is not particularly limited, but it is suitable to adjust it so that Bz / Bp falls within the range of 0.1 to 20.0. Bz / B
When p is less than 0.1, the conversion rate of 4-ABP to DABP is low and it is not industrial, and when Bz / Bp exceeds 20, the step of separating 4,4′-DABP from the reaction solution is efficient. All of them are not preferable because they are not appropriate.

However, the number of moles of ethyl groups of EnTmix is the product of the average number of ethyl groups per one benzene ring of EnTmix and the number of moles of benzene rings of EnTmix (Et.
= (N) × (Bz)), TA in the present invention
EnTmix used as an agent takes into account the n,
It is important to adjust the amount used so that t / (Bz + Bp) becomes 1.0 or more.

Et / (Bz + Bp) is preferably 1.
It is 0 to 3.7. If Et / (Bz + Bp) is less than 1.0, the conversion rate of 4-ABP to DABP is low, or the selectivity of 4,4′-DABP in the produced DABP is low, so it is not industrial, and Et / ( Bz + Bp) is 3.7
When it exceeds the above range, the step of separating 4,4'-DABP from the reaction solution is not efficient, and thus any of them is not preferable.

The Friedel-Crafts catalyst used in the production method of the present invention may be any Friedel-Crafts catalyst. Specific examples include aluminum chloride, aluminum bromide, boron fluoride, iron chloride, antimony chloride, zinc chloride and the like. These Friedel-Crafts catalysts can also be used in an appropriate mixture.

In the present transalkylation reaction, the amount of the catalyst used is not particularly limited, but 0.1 to 50% by weight based on the raw material hydrocarbons is suitable. The amount of catalyst can be appropriately selected depending on the type of Friedel-Crafts catalyst used within this range and the n and amount of the TA agent. The catalyst amount is 0.
If it is less than 1% by weight, the conversion rate of 4-ABP into DABP is low and it is not industrial. Even if the amount of the catalyst exceeds 50% by weight, there is no particular advantage in the reaction and it is uneconomical.

The reaction temperature is suitably 0 to 300 ° C. 0
Below ℃, the reaction rate is slow and not industrial, while 30
If the temperature exceeds 0 ° C., deethylation, transalkylation of the alkyl group of 4-ABP, or production of a large amount of polyalkylbiphenyl such as trialkylbiphenyl or tetraalkylbiphenyl occurs, which is not preferable.

The reaction pressure is not particularly limited as long as the reaction is carried out in the liquid phase, but it is usually 0 to 100 kg / cm ² G
Is appropriate. Even if the reaction pressure exceeds 100 kg / cm ² G, it does not adversely affect the reaction, but it is not particularly required to increase it.

The reaction solvent is not particularly required because the reaction substrate itself can serve as the reaction solvent. However,
It is also possible to use an appropriately known reaction solvent which is inert.

The production method of the present invention can be carried out in either a continuous flow reaction system or a batch reaction system. A flow continuous reaction system is suitable for industrial mass production, and a batch reaction system is suitable for small production.

In the case of production in a continuous flow reaction system, after the transalkylation reaction, the reaction solution is distilled and mainly TO
A fraction composed of L, E1T, E2T, and E3T and having a boiling point lower than that of BP may be ethylated by an arbitrary method and then used as a TA agent. Of BP and high-boiling fractions having a boiling point higher than that of BP, some or all of the fraction excluding 4,4'-DABP and the bottom may be recycled to the transalkylation step. .

After completion of the reaction, the desired product, 4,4'-DABP, can be easily obtained by an appropriate separation means such as distillation.

[0038]

EXAMPLES The present invention will be specifically described below based on examples.

Preparation of EnTmix and EnBmix The EnTmix used in the reaction here was prepared by adding TOL in the presence of a HY-type zeolite catalyst (10% by weight based on TOL).
After ethylation with ethylene, a high-boiling fraction having a boiling point higher than that of E5T was removed by distillation was used. Also, if necessary, TOL from the EnTmix thus obtained,
What removed E1T and E2T by distillation was used.
The reaction temperature for alkylation was 200 ° C., and the reaction pressure was 20 kg / cm ² G with ethylene.

The EnBmix used in the reaction is HY-type zeolite catalyst (10% by weight based on benzene).
After ethylation with ethylene in the presence of benzene, benzene, ethylbenzene, and a high-boiling fraction having a boiling point higher than that of hexaethylbenzene were removed by distillation were used.
The reaction conditions are the same as in the case of the TOL ethylation reaction.

Example 1 A 300 ml three-necked flask equipped with a stirrer was charged with 4-EB.
P150 mmol, EnTmix (n = 3.20) 29
After adding 0.6 mmol (Et / Bp = 6.20 in this case) and purging with nitrogen, 2.31 g of aluminum chloride
Was added, the temperature was raised to 90 ° C. with stirring, and the reaction was performed for 18 hours. After the reaction was completed, it was washed with water and dried, and the reaction solution was analyzed by GLC. The analysis results are shown in Table 1.

Comparative Example 1 As a TA agent, EnBmix was used instead of EnTmix.
The reaction was carried out in the same manner as in Example 1 except that (n = 3.20) was used so that Et / Bp = 6.20. The analysis results are shown in Table 1.

Comparative Examples 2 to 4 As the TA agent, EnTmix (Comparative Example 2) having equimolar amounts of TOL, E1T and E2T and having n = 1.00, and n = 3 having equimolar amounts of E1T, E4T and E5T. 0.33 EnTmix (Comparative Example 3), equimolar E3T, E4
EnTmix in which T = E5T and n = 4.00
The reaction was carried out in the same manner as in Example 1 except that (Comparative Example 4) was used so that Et / Bp = 6.20. The analysis results are shown in Table 1.

Comparative Examples 5 to 8 As the TA agent, E2T (Comparative Example 5), E3T (Comparative Example 6), E4T (Comparative Example 7) and E5T (Comparative Example 8) were used.
The reaction was carried out in the same manner as in Example 1 except that t / Bp = 6.20 was used. The analysis results are shown in Table 1.

Comparative Example 9 As a TA agent, EnTmix (n = 3.20) was used.
The reaction was performed in the same manner as in Example 1 except that t / (Bz + Bp) = 0.91 was used. GL of reaction liquid
The C analysis results are shown in Table 1.

[0046]

[Table 1]

Examples 2 to 3 EnTmix containing TOL and E1T as TA agents
(N = 1.88) 494.7 mmol (Example 2), E
EnTmix (n = 2.47) 376.5m including 1T
The reaction was carried out in the same manner as in Example 1 except that mol (Example 3) was used. The analysis results are shown in Table 2.

Example 4 As a TA agent, EnTmix (n = 3.62) 25
The reaction was performed in the same manner as in Example 1 except that 6.9 mmol was used. The analysis results are shown in Table 2.

Examples 5 to 7 As a TA agent, EnTmix310.0 mmo consisting of equimolar amounts of E2T, E3T and E4T and n = 3.00.
1 (Example 5), EnTmix279.3 mmo with equimolar amounts of E2T, E3T, E5T, n = 3.33.
1 (Example 6), EnTmix 253.4 mmo consisting of equimolar E2T, E4T, E5T with n = 3.67.
The reaction was performed in the same manner as in Example 1 except that 1 (Example 7) was used. The analysis results are shown in Table 2.

Example 8 As a TA agent, EnTmix (n = 3.20) 105
The reaction was performed in the same manner as in Example 1 except that 0.0 mmol was used. The analysis results are shown in Table 2.

[0051]

[Table 2]

Example 9 In a 300 ml three-necked flask equipped with a stirrer, 4-MB
P150 mmol, EnTmix (n = 3.20) 29
After adding 0.6 mmol (Et / Bp = 6.20 in this case) and purging with nitrogen, 2.31 g of aluminum chloride
Was added, the temperature was raised to 90 ° C. with stirring, and the reaction was performed for 18 hours. After the reaction was completed, it was washed with water and dried, and the reaction solution was analyzed by GLC. The analysis results are shown in Table 3.

Comparative Example 10 As a TA agent, EnBmix was used instead of EnTmix.
The reaction was performed in the same manner as in Example 9 except that (n = 3.20) was used so that Et / Bp = 6.20. The analysis results are shown in Table 3.

Comparative Examples 11 to 13 As a TA agent, EnTmix (Comparative Example 11) consisting of equimolar TOL, E1T and E2T and having n = 1.00,
Consisting of equimolar E1T, E4T, E5T, n = 3.33
EnTmix (Comparative Example 12), equimolar E3T,
EnTmi consisting of E4T and E5T with n = 4.00
The reaction was performed in the same manner as in Example 9 except that x (Comparative Example 13) was used so that Et / Bp = 6.20.
The analysis results are shown in Table 3.

Comparative Examples 14 to 17 As TA agents, E2T (Comparative Example 14), E3T (Comparative Example 15), E4T (Comparative Example 16) and E5T (Comparative Example 1)
The reaction was carried out in the same manner as in Example 9 except that 7) was used so that Et / Bp = 6.20. The analysis results are shown in Table 3.

Comparative Example 18 As a TA agent, EnTmix (n = 3.20) was used as Et.
The reaction was carried out in the same manner as in Example 9 except that /(Bz+Bp)=0.91 was used. Table 3 shows the analysis results
Shown in.

[0057]

[Table 3]

[0058]

EFFECTS OF THE INVENTION According to the present invention, 4,4'-DABP is produced from EnTmix, which is an economical reaction raw material, with a selectivity as high as that of the conventional method and at a much higher production rate than that of the conventional method. You can According to the invention, 4-ABP D
When the conversion rate to ABP is 20% or more, the selectivity of 4,4′-DABP in the produced DABP is 75% or more, and when the reaction conditions are optimized, the conversion rate of 4-ABP to DABP 43 %, 4,4'-DAB in produced DABP
The P selectivity is 92% or more. Further, according to the present invention, after the transalkylation reaction, the reaction solution is distilled, and mainly TO
A low-boiling fraction consisting of L, E1T, E2T, and E3T and having a boiling point lower than that of BP may be ethylated by an arbitrary method and then used again as a transalkylating agent. BP and a boiling point of BP Of the above high boiling fractions, 4,
The fraction excluding 4'-DABP and a part or the whole of the residue in the kettle may be recycled to the transalkylation step. Therefore, an ethylating agent such as ethylene as a raw material and 4-AB
Since P can be substantially 4,4'-DABP in its total amount, its industrial significance is extremely high.

Claims (3)

[Claims] 1. A 4-alkylbiphenyl in the presence of a Friedel-Crafts catalyst containing diethyltoluene or triethyltoluene, wherein the average number of ethyl groups per benzene ring is represented by the following formula: 1.1 ≦ n ≦ 3.9 ( Where n represents the average number of ethyl groups per benzene ring), the number of moles of ethyl groups in the mixture of polyethyltoluene, the number of moles of benzene ring in the mixture of polyethyltoluene and biphenyl of 4-alkylbiphenyl. The total ratio of the number of ring moles is represented by the following formula: 1.0 ≦ Et / (Bz + Bp) (where Et is the number of ethyl group moles of the polyethyltoluene mixture, Bz is the number of benzene ring moles of the polyethyltoluene mixture, and Bp is 4). -Representing the number of moles of biphenyl ring of alkylbiphenyl) 4,4'- Method of manufacturing alkyl biphenyl. 2. The method for producing 4,4′-diethylbiphenyl according to claim 1, wherein the 4-alkylbiphenyl is 4-ethylbiphenyl. 3. The 4-ethyl-biphenyl according to claim 1, wherein the 4-alkylbiphenyl is 4-methylbiphenyl.
Process for producing 4'-methylbiphenyl.