JPH029830A - Preparation of dialkylbenzene containing p-isomer in high amount - Google Patents

Abstract

PURPOSE:To provide the subject compound by transalkylating an (alkyl)benzene, polyalkylbenzenes circulated from a distillation process, etc., in the presence of a Friedel Crafts catalyst and subjecting to in turn an alkylation process, an isomerization process and the distillation process. CONSTITUTION:In a transalkylation reaction process an (alkylated) benzene 1 (e.g., toluene), a polyalkylbenzene 6 (e.g., polyisopropyltoluene) circulated from a distillation process IV, a dialkylbenzene 5 (e.g., cymene) containing the m-isomer thereof in a high content and unreacted raw materials 7 are subjected to a transalkylation reaction in the presence of a Friedel Crafts catalyst 2 (e.g., AlCl3). The reaction product is reacted with an alkylating agent 3 (e.g., propylene) in an alkylation process II, subjecting the product to an isomerization reaction process (III) in the presence of a Friedel Crafts catalyst at 30-100 deg.C and sending the reaction products to a distillation process (IV) to provide the subject compound having a m-isomer/(p-isomer + m-isomer) ratio of <=65% (preferably 40-60%).

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an improvement in a method for producing baladialkylbenzene (hereinafter referred to as p-dialkylbenzene).

p-Dialkylbenzene, such as paraisopropyltoluene (hereinafter referred to as p-cymene), is an important compound as a raw material for para-cresol, for example, and baradiisopropylbenzene is an important compound as a raw material for hydroquinone.

<Prior art and its problems> Dialkylbenzenes such as isopropyltoluene (hereinafter referred to as cymene) and diisopropylbenzene have o-form,
There are three isomers: m-isomer and p-isomer. These dialkylbenzenes, for example, cymene, are usually synthesized by alkylating toluene with propylene using a catalyst such as aluminum chloride. The ratio of is close to the equilibrium composition.

That is, aluminum chloride has strong activity as an alkylation catalyst and is therefore used as an industrially useful catalyst.

However, aluminum chloride is known to act as an alkylation catalyst as well as an isomerization catalyst.

Therefore, due to the isomerization reaction accompanying alkylation, a large amount of m-cymene is present in the product.
, m-cymene/(p-cymene + m-cymene) ratio is approximately 65
~70% (Organic Synthetic Chemistry Vol. 38, No. 7, p. 7)
14 (1980)).

Furthermore, in the above reaction, a large amount of alkylated polyalkylbenzenes (hereinafter referred to as polyalkylbenzenes) such as diisopropyltoluene and triisopropylbenzene are usually produced as by-products.

<Problems to be Solved by the Invention> Cresol produced using such a mixed cymene as a raw material has a ratio of its isomers depending on the equilibrium composition of cymene. Since the demand for each isomer of cresol does not necessarily match the production ratio of each isomer of cresol determined by the equilibrium composition of cymene, it is desirable to be able to produce it in accordance with the demand. If only a specific cymene isomer can be produced in a high content, it will be possible to change the production ratio of each cresol isomer, which is determined by the equilibrium composition of cymene, and this can be said to have great industrial significance due to its great taste.

The importance of para-cresol as an antioxidant or a raw material for medicine and agrochemicals is increasing, and it is desired to establish a production method in which para-cresol is present in excess of the equilibrium composition of the cymene isomer.

The metacresol/(valacresol+metacresol) ratio in cresol obtained from cymene at equilibrium composition is approximately 6.
5 to 70%, but because the difference in boiling point between metacresol and paracresol is very small, it is difficult to separate them by distillation as it is, and it is necessary to use a complicated method of, for example, butylation → distillation separation → debutylation. , not only is the cost of separation high, but meta-cresol separated in this way is
This excess amount has become a major obstacle in determining optimal production and quantity.

On the other hand, if the isomers could be separated in an inexpensive manner at the mixed cymene stage, the unnecessary m-cymene isomer would be recycled into the reaction system together with polyisopropyltoluene, resulting in a high content of effective p-cymene after isomerization. This is extremely convenient since simene is obtained as a result.

In the oxidation of cymene and subsequent decomposition reaction (so-called HPO method), the yield of orthocresol obtained from 0-cymene is low, and the oxidation and decomposition yields of other isomers are low due to the by-products produced. adversely affect.

Therefore, in order to obtain para-cresol with high efficiency, it is necessary not only to increase the p-cymene content in cymene, but also to reduce the 0-cymene content to a range that does not substantially cause any adverse effects.

As a measure to solve the above problem, the main components are cymene, polyisopropyltoluene, unreacted toluene, etc. produced in an alkylation reaction step in which toluene and propylene are reacted in the presence of a Friedel-Crafts catalyst containing aluminum chloride as an essential component. The reaction product is subjected to a transalkylation reaction process in the presence of a Friedel-Crafts catalyst containing aluminum chloride as an essential component together with polyisopropyltoluene recycled from the distillation process, and then the transalkylation reaction product is distilled. Accordingly, the cymene fraction and other fractions are fractionated to obtain cymene as a product, while other fractions that are not obtained as products, such as the toluene fraction, are sent to the alkylation reaction step and/or transalkylation reaction step. A possible method is to circulate polyisopropyltoluene to the transalkylation reaction step.

However, it has been found that the isomer ratio of cymene obtained by such a method is close to an equilibrium composition, which is far from the objective of the present invention, which is to obtain a high content of p-cymene. In other words, even if you attempt to separate cymene with a high content of m-cymene by distillation and obtain a product cymene with a high content of p-7-mene, distilling cumene with a composition close to equilibrium will result in a heavy distillation process. Since cymene having a large amount of m-cymene and a high content of m-cymene must be distilled off in large quantities, it is extremely disadvantageous in terms of energy and production efficiency.

Therefore, if cymene with a high content of polyisopropyltoluene and/or m-cymene can be recycled to the reaction system and the p-cymene ratio of cymene obtained from the reaction system can be made to be in excess of the equilibrium composition, it would be extremely useful. It's convenient.

<Means for Solving the Problems> In view of the above-mentioned circumstances, the present inventors have made extensive studies and have successfully combined the transalkylation reaction process, alkylation reaction process, isomerization reaction process, and distillation process. By combining these methods, a method for producing cumene with a high p-cymene content was discovered, and the present invention was achieved.

That is, the present invention provides (III) the following distillation process (IV) with optionally alkylated benzene in the presence of a Friedel Krach catalyst.
) A transalkylation reaction step ( ■) The product of the above transalkylation reaction step (1) is transferred from the following distillation process fl (■) to Ill if necessary.
Alkylation reaction step (III) of producing a dialkylbenzene isomer mixture by reacting a portion of the unreacted optionally alkylated benzene with an alkylating agent in the presence of a catalyst. The product of step (II) is free-treated in the substantial absence of alkylating agent.
Isomerization reaction step (IV) in which the product of the isomerization reaction step (III) is subjected to an isomerization reaction in the presence of a Zoltara fluorocatalyst. It is characterized by comprising each step of a distillation process in which a mixture of dialkylbenzene isomers having a high content of p and unreacted optionally alkylated benzene are separated from a mixture of dialkylbenzene isomers having a high content of p. This is a method for producing dialkylbenzene with a high content of p-units.

Examples of the optionally alkylated benzene according to the present invention include benzene, toluene, ethylbenzene, isopropylbenzene (cumene), and the like.

The dialkylbenzene isomer mixture referred to in the present invention includes isomer mixtures of cumene, diisopropylbenzene, xylene, ethyltoluene, diethylbenzene, and the like.

The polyalkylbenzene recycled from the distillation step (IV) in the present invention refers to diisopropyltoluene, triisopropylbenzene, and the like.

The alkylating agent used in the present invention includes lower olefins such as ethylene, propylene, butylene, ethanol,
Lower alcohols such as Impropatool or methyl chloride, ethyl chloride, isopropyl chloride,
Examples include halogenated lower alkyls such as isopropyl bromide, among which propylene is preferably used.

Hereinafter, preferred embodiments of the method of the present invention will be explained in more detail based on FIG. 1, using cymene as an example of dialkylbenzene.

FIG. 1 is a flow sheet diagram of the main part of the reaction process of the present invention.

In the figure, (1) is the transalkylation reaction step, (II)
is an alkylation reaction step, (II[) is an isomerization reaction step,
(IV) represents a distillation/separation step.

In addition, the numbers in the figure have the following meanings.

1 Optionally alkylated benzene (specific example: toluene) 2 Catalyst 3 Alkylating agent (specific example: propylene) 4 Dialkylbenzene with a high content of p-cymene (specific example: cymene with a high content of p-cymene) ) 5 Dialkylbenzene with a high content of m (specific example; cymene with a high content of m-cymene) 6 Polyalkylbenzene (specific example: polyisopropyltoluene) 7 Unreacted optionally alkylated benzene (Specific example: unreacted toluene) First, in the transalkylation reaction step (1), the raw material toluene (indicated as 1 in the figure) is separated from the catalyst (indicated as 2-1 in the figure) and the distillation step (IV). Cymene with a high content of mainly m-7mene (indicated as 5 in the figure),
A transalkylation reaction is carried out using polyisopropyltoluene (indicated as 6 in the figure) and part or all of unreacted toluene (indicated as 7 in the figure).

Next, the product of the alkylation reaction step (formerly, the above transalkylation reaction step) is subjected to a distillation step (IV) if necessary.
) along with a portion of unreacted toluene 7 separated from
React with propylene (labeled 3 in the figure) in the presence of a catalyst.

Next, in the isomerization reaction step (II[), the alkylation reaction product is subjected to an isomerization reaction in the substantial absence of propylene and in the presence of a Friedel-Crafts catalyst.

Next, in the distillation step (IV), cymene with a high content of m-cymene (indicated as 5 in the figure), polyisopropyltoluene 6 and unreacted toluene 7 are converted into cymene with a high content of p-cymene (indicated as 5 in the figure). 4)). The separated cymene 5 with a high content of m-cymene, polyisopropyltoluene 6 and unreacted toluene 7 are recycled to the first transalkylation step (1), while the target p-cymene with a high content is recycled. Cymene 4 is fractionated.

The present invention requires each of the steps (1) to (IV) above to be carried out, but if necessary, each step may be carried out in two stages, or other steps may be carried out, as long as the spirit of the present invention is met. It is permissible to incorporate additional/supplementary processes.

Each step of the present invention will be explained in more detail below.

Among the steps of the present invention, (III) to (II[)
The steps are carried out in the presence of a catalyst, and among them, the transalkylation reaction step (1) and the isomerization reaction step (
[[Each step in [] must be carried out in the presence of a Friedel-Crafts catalyst.

As the free delta raft catalyst used here, one containing aluminum chloride as an essential component is particularly preferably used. Specifically, for example, aluminum trichloride 1
Catalysts prepared from about 0.3 to about 2 molar parts of hydrogen chloride as a cocatalyst and an aromatic hydrocarbon such as toluene or men are preferably used. Here, when aluminum trichloride, hydrogen chloride, and aromatic hydrocarbons come into contact, they react to form a high specific gravity oily complex with a complex structure, and this complex is different from the low specific gravity aromatic hydrocarbon phase. form another phase. This complex then functions as a Friedel-Crafts catalyst for alkylation reactions, transalkylation reactions, and isomerization reactions.

Therefore, in the transalkylation reaction step (III) and the isomerization reaction step (III), the above-mentioned composite phase and the aromatic hydrocarbon phase are brought into contact, and the transalkylation reaction and
An alkylation reaction and an isomerization reaction will proceed.

The catalyst used in the alkylation reaction step (II) of the present invention is not limited to the Friedel-Crafts catalyst, but of course the aluminum chloride catalyst used as the composite phase is also preferably used.

In addition, as a Friedel-Crafts catalyst, G.

Catalysts such as those listed in the article "A. 0LAHr Free-Sol Tarafts and Related Reactions", Vol. 1, pp. 191-197 (1963) can be used.

The Friedel-Crafts catalyst that can be used in the method of the present invention is
Especially the periodic table 3rd column, 4'a, 5'a, 1b, 2b,
halides of elements of groups 4b, 5b, 6b, 7b and 8, which are liquid or solid under operating conditions, such as aluminium, tin, phosphorus, antimony, arsenic, bismuth, titanium, tantalum, niobium, These are the chlorides, bromides, fluorides and iodides of zirconium, vanadium, tungsten, molybdenum, iron, cobalt, nickel, copper, zinc, silver and cadmium. Specific examples of these halides are aluminum chloride, aluminum bromide. , stannic and dichloride, stannic and dibromide, bismuth trichloride, titanium tetrachloride,
Zirconium tetrachloride, antimony pentafluoride, tungsten hexachloride, molybdenum chloride, ferric chloride, ferrous chloride,
Mention may be made of ferric bromide, ferrous bromide, cuprous chloride, cupric chloride, silver chloride and zinc chloride.

Preferable examples of these Friedel-Craft catalysts include aluminum chloride, ferric chloride, zirconium tetrachloride, and titanium tetrachloride. More preferred is aluminum chloride, and it is even more convenient to use it as a complex with toluene.

These catalysts can be used not only alone but also in combination with other catalysts. That is, examples of combinations thereof include aluminum chloride, ferric chloride, cuprous chloride, and silver chloride.

Furthermore, combinations of aluminum chloride and metal chlorides may also be mentioned. That is, aluminum chloride, sodium chloride, lithium chloride, calcium chloride, etc. can be mentioned.

Further examples include complexes of aluminum chloride and certain organic compounds. Specifically, complexes of aluminum chloride and carbon tetrachloride, chloroform, ethers, phosphorus compounds, oxygen compounds, nitromethane, and the like can also be used.

Further types of complexes of Lewis acids and hydric acids can also be used. That is, for example, the complex S b Fs.HF or BF3.HF can be mentioned.

In the process of the present invention, what is important is that in the alkylation reaction step (n) of reacting with an alkylating agent, the ratio of 〇-isomer in the dialkylbenzene produced is about 10%.
The above is preferably about 20% or more, and the m-isomer/(p=isomer+m-isomer) ratio is about 65% or less, preferably about 50% or less. Then, the alkylation reaction product is treated in the substantial absence of an alkylating agent at a reaction temperature of preferably about 30 to 100° C. using a Friedel-Crafts catalyst containing aluminum chloride as an essential component to obtain a 〇-isomer ratio. about 10% or less, preferably about 8
% or less.

This leads to good results for producing dialkylbenzene with a high content of p-units.

Hereinafter, by further explaining the present invention, the objects of the present invention,
Benefits etc. will be better understood.

In the transalkylation reaction step (III), the amount of benzene nuclei supplied to the step (1) is 0.1 to
10 mol %, preferably 0.1 to 5 mol %, more preferably 0.2 to 1 mol % of said catalyst are present;
In the isomerization reaction step (II [>), 0.05 to 10 mol% based on the benzene nucleus supplied to the step (nl),
Preferably 0.1 to 5 mol%, more preferably 0.5 to 5 mol%
2 mol% of said catalyst is present.

The catalyst used in the alkylation reaction step (IT) is 0.01 to 10 mol%, preferably 0.1 to 5 mol%, based on the benzene nuclei supplied to the step (II).
More preferably, it is 0.1 to 1 mol%. Here, if the catalyst brought in in the previous transalkylation reaction step (III) is sufficient, it is possible to omit supplying a new catalyst.

The amount of metal compound or organic compound used in combination with aluminum chloride is 0 relative to aluminum chloride.
．． The amount is such that the molar ratio is 5 to 10.

Preferably 0.5-5 molar ratio, more preferably 1.0-5
3 molar ratio.

Transalkylation reaction step (1) of the present invention, alkylation reaction step (II) and isomerization reaction step (III)
The reaction is carried out as a batch, semi-continuous, or continuous reaction.

Although it is possible to separate or remove the catalyst used in each step, it is possible to separate or remove the catalyst from the product of the isomerization reaction step (III) without separating or removing it, and then to provide it to the distillation step. is also possible.

The following methods can be exemplified as industrial embodiments of the steps (1) to (III).

The high specific gravity catalyst phase is separated from the reaction mixture of step (III), and the separated catalyst phase is recycled to step (III) or supplied to step (III). Alternatively, part or the entire amount is supplied to step (II).

In step (II), if a new catalyst is added or aluminum chloride is used, step (1)
After complete complex formation, for example by adding carbon tetrachloride to the reaction mixture containing the catalyst phase supplied from the reactor, the reaction mixture is reacted with propylene and the complex phase is separated from the reaction mixture, or the step (without separation) is carried out. III). In step (III), the catalyst phase separated from step (1) and/or a new catalyst are supplied to carry out the isomerization reaction.

The transalkylation reaction step (III) of the present invention is
This is a process in which the raw material toluene reacts with polyisopropyltoluene and/or cymene containing a high content of m-7mene recycled from the distillation step (IV), resulting in a thermodynamically balanced composition. The composition is 2 to 8% polyisopropyltoluene, 20 to 50% cymene, and 70 to 70% toluene.
40%, and the 0-cymene ratio in cymene is 3-5%,
m-cymene/(p-cymene + m-cymene) ratio is approximately 70%
It is.

If you stop before equilibrium is reached, m-cymene/(
The p-cymene (m-cymene) ratio is 70% or more, which is a disadvantageous composition from the point of view of the present invention.

The reaction temperature in this step (III) is about 30 to 120°C, preferably about 60 to 120°C.

Next, as described above, the alkylation reaction step (n) has a reaction temperature of about 0 to 120°C, preferably about 30 to 100°C.

The propylene used has a propylene/toluene molar ratio of 0.1 to 0, preferably 0.5 to 2.
．． One of the preferable requirements for achieving the object of the present invention is to implement it at a molar ratio of 0, more preferably from 0.6 to 1.0.

The reaction time varies depending on other conditions, namely reaction temperature, amount of propylene used, catalyst used and its amount, but about 0.5 to 10 hours is sufficient to reach the desired composition.

The target composition in this alkylation reaction step (n) is such that the 0-7 mene ratio in the produced cymene is about 10% or more, preferably about 20% or more, more preferably about 30% or more, and m- The cymene/(p-cumene+m-cymene) ratio is about 65% or less, preferably about 50% or less, more preferably about 40% or less.

In order to obtain such a composition, it is necessary to optimize the combination of the above-mentioned reaction conditions.

The reaction product of the alkylation reaction step (n) is subsequently fed to the isomerization reaction step (III), either by separating the catalyst from the reaction product or without separating it (the entire amount is removed from the isomerization reaction step). It may also be supplied to step (III).

In this isomerization reaction step (III), the previous step (
It is important from the industrial point of view of this process to carry out the isomerization reaction until the high content of 0-cymene in II) is reduced to about 10% or less, more preferably about 8% or less.

At this time, substantially p-
Cymene needs to be in excess over the equilibrium composition.

The reaction temperature is about 30-100°C, preferably about 40-80°C.
It is ℃.

The reaction time varies depending on other conditions, such as reaction temperature, amount of catalyst used, etc., but it takes about 0.1~
10 hours is sufficient.

Here, the 0-cymene ratio is set to about 10% or less, more preferably about 8% or less, within a range that does not substantially adversely affect the oxidation and decomposition reactions of other isomers in the so-called HPO method cresol synthesis. I'm talking about the upper limit,
It is not preferable to lower this value pointlessly because this reaction will thermodynamically approach an equilibrium composition, which will increase the ratio of m-cymene.

Therefore, control of the reaction conditions in this isomerization reaction step (II[) is extremely important in achieving the purpose of the present invention.

After the reaction product from the isomerization reaction step (III) is separated from the catalyst, or without separation, the catalyst is completely removed by washing with an alkali, washing with water, etc., and the product is supplied to the distillation step (IV). Note that the separated catalyst can also be recycled and reused.

In the distillation step (IV), cymene having a high content of p-cymene is obtained as a product by distillation.

Alkylated polyisopropyltoluene, which is a high-boiling component, is used in the transalkylation reaction step (1) described above.
). Further, the unreacted toluene fraction, which is a low-boiling component, is recycled to the transalkylation reaction step (III) and, if necessary, to the alkylation reaction step (II).

Furthermore, cymene with a high content of m-cymene is separated by distillation and other various means, and then subjected to the transalkylation reaction step ([
). Or, it does not circulate and contains a high amount of m-cymene.
It is also possible to obtain cymene as a product.

By the method of the present invention described above, cymene having a high content of p-cymene can be obtained as a product.

Here, the ratio of m-cymene/(p-cymene to m-cymene) in cymene with a high content of m-cymene obtained by distillation can be adjusted freely depending on the distillation conditions, but the ratio is approximately 50-90%, preferably about 65-90%, more preferably about 70-85%.

It is recommended that the above steps (1) to (IV) be carried out continuously.

<Effects of the Invention> The effects of the present invention will be explained with reference to the case where cymene is used as the dialkylbenzene.
-Only the equilibrium composition in which cymene can be produced in large quantities was obtained, but as revealed in the present invention, the m-cymene/(p-cymene + m-cymene) ratio is surprisingly about 40 to 60%. We were able to achieve the desired ratio. Or step (IV)
If the cymene with a high content of m-cymene separated in step (1) is obtained as a product without being recycled to step (1), the m-cymene/(p-cumene + m-cymene) ratio will be approximately 40 to 90%. The ratio can now be adjusted freely.

The production ratio of meta-cresol and vala-cresol, which was conventionally fixed for annual production of several hundred tons of cresol, has now become possible to respond flexibly to increased demand for each cresol through the method of the present invention. The matter is extremely important.

<Examples> Hereinafter, the method of the present invention will be explained by examples, but the present invention is not limited by the following examples.

In addition, in the following examples, percentage (%) indicates 1% by weight unless otherwise specified.

Example 1 515 parts of toluene i-ringed from the distillation process/Hr, 275 parts of polyalkylbenzene (diisopropyltoluene)
part/Hr and m-shi) 7/ (p-'ymen+m-
193 parts/Hr of cymene at a ratio of 85% and 327 parts/1-1r of fresh toluene were supplied to the transalkylation reactor. As a catalyst, 40 parts/hr of liquid aluminum chloride (composition: 26% aluminum chloride, 70% toluene, 4% hydrochloric acid) was supplied. The temperature of the transalkylation reactor was 105°C. After about 2 hours of warm-up time,
The composition of the reaction product was 60% toluene, 5% polyalkylbenzene, and 35% cymene. The m-cymene/(p-cymene + m-cymene) ratio in cymene is 69%,
The 0-cymene ratio was 3%.

The reaction product of the transalkylation reactor is supplied to the alkylation reactor, and at the same time 149 parts of propyref/H
I blew r.

The reaction temperature of the alkylation reactor was 75°C. The composition of the reaction product after about 2 hours of residence time was 32% toluene, 20% polyalkylbenzene, and 48% cymene. The m-cymene/(p-cymene ten m-cymene) ratio in cymene is 4
8%, and the O-cymene ratio was 25%.

The reaction product of the alkylation reactor was supplied to the isomerization reactor, and at the same time, the catalyst recycled from the catalyst separation step and 30 parts/hr of liquid aluminum chloride (composition; same as above) were supplied. The reaction temperature of the isomerization reactor was 60°C. After about 1 hour of residence time, the reaction product composition had a cymene content of 50%, m/mene/(p-cymene + m-cymene) ratio in cymene of 55%, and a 0-cymene ratio of 7%. Ta.

The reaction product in the isomerization reactor was supplied to the catalyst separator, and the catalyst phase with high specific gravity was circulated to the isomerization reactor, and a portion was discharged outside the system. The oil phase was washed with alkaline water and washed with water to completely remove catalyst components, and was then supplied to the distillation process at about 1400 parts/Hr.

In the distillation process, unreacted toluene, a low-boiling component, and polyalkylbenzene, a high-boiling component, were first separated, and higher-boiling components were discharged from the system.

The cymene fraction was further separated by distillation to separate a fraction with a high m-cymene ratio, and then about 600 parts/hr of cymene with a high p-cymene content was obtained as a product.

Cymene with a high proportion of toluene, polyalkylbenzene, and m-cymene is circulated to the transalkylation tank, and the composition of the product cymene is 99.9% or more in purity, m-cymene/(
p-cymene+m-cymene) ratio was 48%, and 0-cymene ratio was 8%.

Example 2 Toluene 515/Hr recycled from the distillation process.

Polyalkylbenzene (diisopropyltoluene) 27
5 parts/Hr and m-cymene/(p-cymene+m-
193 parts/Hr of cymene at a ratio of 85% (cymene) and 327 parts/Hr of fresh toluene were supplied to the transalkylation reactor. As a catalyst, 40 parts/hr of liquid aluminum chloride (composition: same as above) was supplied. The temperature of the transalkylation reactor was 105°C. After about 2 hours of residence time, the composition of the reaction product was 60% toluene, 5% polyalkylbenzene, and 35% cymene. m- in cymene
The cymene/(p-cymene+m-cymene) ratio was 69%, and the 0-cymene ratio was 3%.

The reaction product of the transalkylation reaction tank was supplied to the catalyst adjustment tank, and at the same time 1r of carbon tetrachloride (15 parts/) was added. After a residence time of 30 minutes, the reactor was fed to the alkylation reactor, and at the same time 149 parts of propylene/Hr was blown into the reactor.

The reaction temperature of the alkylation reactor was 75°C. The composition of the reaction product after about 2 hours of residence time was 29% toluene, 28% polyalkylbenzene, and 43% cymene. The m-cymene/(p-cymene + m-cymene) ratio in cymene is 4
5%, and the 0-cymene ratio was 29%.

The reaction product of the alkylation reactor was supplied to the isomerization reactor, and at the same time, the catalyst recycled from the catalyst separation step and 60 parts/Hr of liquid aluminum chloride (composition: same as above) were newly supplied. The reaction temperature of the isomerization reactor was set at 60°C. After about 1 hour of residence time, the reaction product composition contained 149% cumene, the m-cymene/(p-cymene + m-cymene) ratio in cymene was 53%, and the O-cymene ratio was 8%. Ta.

The reaction product in the isomerization reactor was supplied to the catalyst separator, and the catalyst phase with high specific gravity was circulated to the isomerization reactor, and a portion was discharged outside the system. The oil phase was washed with alkaline water and washed with water to completely remove catalyst components, and was then supplied to the distillation process at about 1400 parts/Hr.

In the distillation process, unreacted toluene, a low-boiling component, and polyalkylbenzene, a high-boiling component, were first separated, and higher-boiling components were discharged from the system.

The cymene fraction was further separated by distillation to separate a fraction with a high m-cymene ratio, and then approximately 6001/Hr of cymene with a high p-cymene content was obtained as a product.

Toluene, polyalkylbenzene and cymene with a high m-cymene ratio are recycled to the transalkylation FIJ,
The composition of the product cumene was 99.9% or higher in purity, an m-cymene/(p-cumene+m-cymene) ratio of 45%, and an 0-cymene ratio of 8%.

Example 3 515 parts/Hr of toluene recycled from the distillation process.

Polyalkylbenzene (diisopropyltoluene) 27
5 parts/Hr and m-cylinder/(1)-shime 7+m
- Cymene) 193 parts/Hr of 90% cymene and 327 parts/Hr of fresh toluene were supplied to the transalkylation reactor. As a catalyst, 40 parts/hr of liquid aluminum chloride (composition; same as above) was supplied. The temperature of the transalkylation reactor was 100°C. Residence time approx. 2
After an hour, the composition of the reaction product was 60% toluene, 5% polyalkylbenzene, 35% cymene. m-cymene/(p-cymene + m-cymene) ratio in cymene is 69%
The O-cymene ratio was 3%.

The reaction product of the above transalkylation reaction tank is supplied to the alkylation reaction tank, and at the same time, the reaction product of the transalkylation reaction tank is
7 parts of sodium chloride/Hr were added.

The reaction temperature of the alkylation reactor was 80°C. The composition of the reaction product after about 2 hours of residence time was 42% toluene, 19% polyalkylbenzene, and 39% cymene. The m-cymene/(p-cymene ten m-cymene) ratio in cymene is 4
6%, and the 0-cymene ratio was 25%.

The reaction product of the alkylation reaction tank was supplied to the isomerization reaction tank, and 60 parts/Hr of liquid aluminum chloride (composition - same as above) was newly supplied. The reaction temperature of the isomerization reactor was 60°C. After about 1 hour of residence time, the reaction product composition contains cymene! 47%, the m-cymene/(p-cymene + m-cymene) ratio in cymene is 56%, and the O-cymene ratio is 7.
%Met.

The reaction product of the isomerization reaction was subjected to alkaline washing and water washing to completely remove catalyst components, and was then supplied to the distillation process at about 1400 parts/Hr.

In the distillation process, unreacted toluene, a low-boiling component, and polyalkylbenzene, a high-boiling component, were first separated, and higher-boiling components were discharged from the system.

The cymene fraction was further separated by distillation to separate a fraction with a high m-cymene ratio, and then approximately 6001/Hr of cymene with a high p-cymene content was obtained as a product.

Cymene with a high proportion of toluene, polyalkylbenzene and m-cymene is recycled to transalkyl ([F), and the composition of the product cymene is 99.9% purity or higher,
The (p-cymene+m-7mene) ratio was 40%, and the 0-cymene ratio was 9%.

Example 4 Cumene 665 parts/Hr, polyalkylbenzene (triisopropylbenzene) 317 parts recycled from the distillation process
parts/Hr, and m-diisopropylbenzene 226
part/Hr and 422 parts/Hr of fresh cumene were supplied to the transalkylation reactor. Liquid aluminum chloride (composition: 26% aluminum chloride, 70% cumene, 4% hydrochloric acid >40!/Hr was supplied as a catalyst. The temperature of the transalkylation reactor was 100°C. After about 2 hours of residence time, reaction products were formed. The composition of the product is 61% cumene, 8% polyalkylbenzene, and 31% diisopropylbenzene.
Met. The m-diisopropylbenzene/(p-diisopropylbenzene/m-diisopropylbenzene) ratio in diisopropylbenzene was 72%, and the 0-diisopropylbenzene ratio was 3%.

The reaction product of the transalkylation reactor is fed to the alkylation reactor, and at the same time 149 parts of propylene/
Hr was added.

The reaction temperature of the alkylation reactor was 90°C. After about 2 hours of residence time, the reaction product composition was 38% cumene, 22% polyalkylbenzene, and 40% diisopropylbenzene.
Met. The m-diisopropylbenzene/(p-diisopropylbenzene/m-diisopropylbenzene) ratio in diisopropylbenzene was 41%, and the 0-diisopropylbenzene ratio was 20%.

The reaction product of the alkylation reaction was supplied to the isomerization reaction tank, and a fresh supply of 60 parts/Hr of liquid aluminum chloride (composition; same as above) was supplied. The reaction temperature of the isomerization reactor was 60°C. The composition of the reaction product after a residence time of about 1 hour was a diisopropylbenzene content of 52%, a m~diisopropylbenzene/(p-diisopropylbenzene~m-diisopropylbenzene) ratio in diisopropylbenzene of 57%, and a 0- Diisopropylbenzene ratio is 3%
Met.

The reaction product of the isomerization reaction was subjected to alkaline washing and water washing to completely remove catalyst components, and was then supplied to the distillation process at about 1780 parts/Hr.

In the distillation process, unreacted cumene, a low-boiling component, and polyalkylbenzene, a high-boiling component, were first separated, and higher-boiling components were discharged from the system.

The diisopropylbenzene fraction is further distilled to separate a fraction with a high m-diisopropylbenzene ratio, and then p-
Approximately 550 parts/hr of diisopropylbenzene with a high content of diisopropylbenzene was obtained as a product.

Diinepropylbenzene with a high proportion of cumene, polyalkylbenzene and m-diisopropylbenzene is circulated to the transalkylation tank, and the composition of the product diisopropylbenzene is 99.9% or more in purity, m-diisopropylbenzene/(p-diisopropylbenzene + m-diisopropylbenzene). -diisopropylbenzene) ratio was 23%, and the 0-diisopropylbenzene ratio was 5%.

[Brief explanation of the drawing]

FIG. 1 is a flow route diagram of the main parts of the reaction process of the present invention. In the diagram, the symbols and numbers represent the following meanings. (III) Transalkylation reaction step, (II)
Alkylation reaction step, (1) Isomerization reaction step, (IV) Distillation/separation step, l Optionally alkylated benzene (specific example: toluene) Catalytic alkylating agent (specific example: propylene) Dialkylbenzene content (specific example; p
- cymene with a high content of cymene) 5 Dialkylbenzene with a high content of m-monocarbons (Specific example - cumene with a high content of m-cymene) Polyalkylbenzene (Specific example: polyisopropyltoluene) Unreacted alkylated Benzene (specific example, unreacted toluene) Procedural amendment (spontaneous) Indication of the case Patent Application No. 162113 of 1988 2, Title of the invention Process for producing dialkylbenzene with high content of p-1, 3, Relationship with the case of the person making the amendment Patent applicant ■ (209) Sumitomo Chemical Co., Ltd. Representative Hideo Mori 4, Agent 5-5-33 Kitahama 4-chome, Chuo-ku, Osaka City, ``Invention'' of the specification subject to amendment Column 6 of ``Detailed Explanation of ``, contents of amendment (1) The following sentence is inserted between lines 6 and 7 of page 14 of the specification. ``Also, the number of reaction vessels in each step of (III) to (III) is not particularly limited, and necessary vessels may be added as needed to maintain the residence time necessary to reach the target composition. It can be used continuously.The number of reaction vessels in each of these steps is preferably selected from 1 to 5 due to economic efficiency or operational management constraints.'' (2) Specification, page 19 Insert the following statement between the 15th and 16th lines. "Also, the transalkylation step (1), alkylation step (n), and isomerization step (II[) are carried out in an appropriate number of reaction vessels according to the required reaction time." (3) Specification Insert the following sentence between page 20, line 16 and line 17. "Also, the separated catalyst phase can be reused in step (II), and in that case, the catalyst phase can be activated as is or by blowing hydrogen chloride gas etc. that does not contain substantially water. In addition, by blowing hydrogen chloride gas containing substantially no water into the reaction system in step (III), the catalyst activity can be increased and the reaction can proceed smoothly. "that's all

Claims (1)

[Claims] (1) (I) Optionally alkylated benzene in the presence of a Friedel-Crafts catalyst and the following distillation step (IV)
A transalkylation reaction step in which a dialkylbenzene isomer mixture containing a high content of polyalkylbenzene and/or m-isomer recycled from II) The product of the above transalkylation reaction step (I) is mixed with a part of the unreacted and optionally alkylated benzene recycled from the following distillation step (IV) if necessary, in the presence of a catalyst, Alkylation reaction step (III) of reacting with an alkylating agent to produce a dialkylbenzene isomer mixture. Isomerization reaction step (IV) in which the product of the isomerization reaction step (III) is subjected to an isomerization reaction in the presence of a catalyst. It is characterized by comprising each step of a distillation process for separating a dialkylbenzene isomer mixture having a high content and unreacted optionally alkylated benzene from a dialkylbenzene isomer mixture having a high content of p-isomers. A method for producing dialkylbenzene with a high content of p-isomer. (2) In the alkylation reaction step (II), the o-isomer ratio in the resulting dialkylbenzene isomer mixture is about 10% or more, and the m-isomer/(p-isomer + m-isomer) ratio is about 65%. Process according to claim 1, characterized in that the reaction is completed as follows. (3) The method according to claim 1 or 2, wherein the isomerization reaction step (III) is carried out at a temperature of about 30 to 100°C. (4) Any one of claims (1) to (3), characterized in that in the isomerization reaction step (III), the reaction is completed with the o-isomer ratio in the resulting dialkylbenzene isomer mixture being about 10% or less. Method described in Crab. (5) Transalkylation reaction step (I) for about 30 minutes
The method according to any one of claims (1) to (4), carried out at a temperature of -120<0>C.