JPH07233099A - Continuous production of monoalkyl aromatic hydrocarbon - Google Patents

Abstract

PURPOSE:To continuously produce a monoalkyl aromatic hydrocarbon in high yield and efficiency by introducing an aromatic hydrocarbon and an olefin into a former- stage reaction part to effect the alkylation reaction of the hydrocarbon and introducing the reaction product into the latter-stage reaction part together with a polyalkyl aromatic hydrocarbon formed in the latter-stage reaction part to effect the transalkylation reaction. CONSTITUTION:This process for the continuous production of a monoalkyl aromatic hydrocarbon comprises the use of a reactor composed of a former-stage reaction part and a latter-stage reaction part, the introduction of a Friedel-Crafts' catalyst, an aromatic hydrocarbon and an olefin into the former-stage reaction part to effect the alkylation reaction at an olefin conversion of 30-99% while concurrently flowing the components in mixed phase, the introduction of the effluent of the former-stage reaction part and a polyalkyl aromatic hydrocarbon separated from the effluent of the latter-stage reaction part into the latter-stage reaction part and the reaction of the components mainly by transalkylation at an olefin conversion of 100%. Preferably, the reactor is composed of a single vessel separated into the former-stage reaction part and the latter-stage reaction part with a porous partition member such as a perforated plate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous process for producing monoalkyl aromatic hydrocarbons, and more particularly to a novel process for producing monoalkyl aromatic hydrocarbons by reacting an olefin with an aromatic hydrocarbon compound. And improved method. Monoalkyl aromatic hydrocarbons, such as ethylbenzene, have been used in large quantities to produce high-demand polystyrene as well as the styrene monomer that is the raw material for many copolymers.

[0002]

2. Description of the Related Art Conventionally, as an example of a method for producing a monoalkyl aromatic hydrocarbon by reacting an aromatic hydrocarbon with an olefin, aluminum chloride is used as an alkylation catalyst and ethylbenzene is converted by an alkylation reaction of benzene and ethylene. The case of manufacturing will be described.

The most general method for producing ethylbenzene is a method in which an alkylation reaction and a transalkylation reaction are carried out simultaneously in one reactor 21 as shown in FIG. Benzene 12A, which is the raw material, is separated and recovered in the subsequent stage 23.
Gaseous ethylene 11 is also continuously introduced into the reactor front part 15 together with benzene 14A from At that time,
Aluminum chloride and hydrochloric acid (or ethyl chloride) catalyst (co-catalyst) 20 is also continuously continuously at the bottom of reactor 21.
Introduce to 5. The reaction is carried out in the liquid phase in excess of benzene, and ethylene substantially completes the alkylation reaction in the reactor 21.

The molar ratio of ethyl groups to the benzene ring fed to the reactor is an important operating condition and affects the equilibrium composition in the transalkylation reaction in parallel with the alkylation reaction. The equilibrium constant of the transalkylation reaction is shown as

[0005]

[Chemical 1]

FIG. 5 shows the equilibrium composition based on the equilibrium constant with respect to the molar ratio of ethyl group and benzene ring.
As shown in FIG. 5, when the molar ratio is increased, the amount of polyethylbenzene produced is increased, so that the separation energy of polyethylbenzene in the separation / recovery facility 23 is increased. On the other hand, since the amount of unreacted benzene is reduced, the separation energy of benzene is reduced. The optimum molar ratio is determined from the balance between the two and the condition of the separation and recovery facility 23.

The main reaction alkylation reaction is about 27 (kca).
It is an exothermic reaction of 1 / mol-EB). This heat of reaction is mainly used for the evaporation of benzene in the reaction liquid, and the evaporated benzene is condensed into a liquid phase benzene 13 by a condenser 22 connected to the reactor rear part 18 and reintroduced into the reactor front part 15. To be done. At the same time, the heat of condensation is effectively recovered and used by the separation and separation energy of the separation and recovery equipment and steam generation.

Since the aluminum chloride complex of the catalyst has a very strong corrosive property, the reactor 21 is made of a corrosion resistant material such as hastelloy or an inner lining such as acid brick. The effluent 17 other than gas in the reactor rear part 18 is neutralized and washed with water in order to remove the dissolved aluminum chloride and hydrochloric acid after separating the catalyst in the separation / recovery facility 23. Further, benzene, ethylbenzene and polyethylbenzene are separated in this order, and finally polyethylbenzene and heavy substances such as flux are separated. Here, polyethylbenzene is a higher alkylated benzene having two or more ethyl groups, such as diethylbenzene, triethylbenzene, and tetraethylbenzene. Polyethylbenzene 16A as well as the separated unreacted benzene is introduced into the reactor front part 15 and converted into ethylbenzene by the transalkylation reaction. Incinerate other heavy materials. In this way, ethylbenzene 19A was continuously produced.

In this conventional method, the alkylation and transalkylation reactions can be carried out in one reactor 21, but the production amount of heavy substances such as flux is large and the yield or selectivity of ethylbenzene is low. The composition of the reaction product liquid is
The closer to the reaction equilibrium composition, the smaller the separation and recovery equipment and the energy required. However, the reactor 21 requires a relatively large reaction volume in order to approach the reaction equilibrium composition, and the productivity is low.

Therefore, Japanese Patent Publication No. Sho 61 has tried to improve productivity.
No. 3,67,29, the reactor is integrated and configured in an integrated alkylation-transalkylation type consisting of an alkylation zone around the central axis spaced from the top and a transalkylation zone surrounding this zone. Has been done. However, even in this method, essentially all the reaction of ethylene has to be completed at the outlet end of the alkylation zone, so that the volume of the alkylation reaction zone required for this is large and the productivity is low.

[0011]

Therefore, as a measure for improving the yield and productivity, first, the reaction of a gas-liquid mixed phase flow will be considered. In the alkylation reaction, a liquid phase mainly composed of a catalyst, a raw material benzene and an alkylation reaction product such as ethylbenzene or polyethylbenzene, and a gas phase mainly composed of ethylene gas are present. Usually, the liquid phase is a continuous phase. The gas phase exists in the form of bubbles, that is, as a dispersed phase. The alkylation reaction is carried out in the liquid phase by absorbing ethylene gas in the bubbles into the liquid phase. The alkylation reaction in the liquid phase is a very fast reaction even with a small amount of catalyst and is an exothermic reaction. As the reaction progresses, Hensen evaporates and is mixed in the bubbles. At the moment when ethylene was supplied, the ethylene concentration in the bubbles was high and the ethylene gas was quickly absorbed.However, when the reaction proceeded along with the flow of bubbles, the ethylene gas in the bubbles was absorbed in the liquid phase, and benzene became liquid. The phases evaporate and mix into the bubbles. The ethylene concentration in the bubbles decreases, and the drying force for absorption decreases,
A considerable residence time is required until the ethylene gas in the bubbles is completely absorbed in the liquid phase.

That is, the rate at which ethylene in the gas phase is absorbed into the liquid phase becomes a problem, and when the residence time is shortened, the absorption of ethylene gas becomes insufficient and ethylene is purged as an unreacted gas, so that the raw material ethylene fed is supplied. The yield of ethylbenzene per unit decreases. Therefore, it is possible to return unreacted ethylene to the reactor by using a recovery device such as a recycle compressor. However, the recovery device will be a facility made of corrosive material and used for driving an ethylene recycle compressor. This is also undesirable because it requires energy. In order to complete the alkylation reaction in the alkylation reaction zone where the absorption of ethylene gas is rate-determining, the residence time becomes long in the alkylation reaction zone.

Next, even in the reaction in the liquid single phase, in order to complete the alkylation reaction in the alkylation reaction zone,
Immediately before the completion of the reaction, the ethylene concentration in the liquid becomes very low, and the residence time in the alkylation reaction zone also becomes long. Thus, nothing has been solved about the low productivity in the alkylation reaction zone.

The present invention provides a monoalkyl aromatic hydrocarbon which produces a small amount of a heavy product and has a high yield or selectivity of a monoalkyl aromatic hydrocarbon and which has a high productivity in an alkylation reaction and a transalkylation reaction. A manufacturing method is provided.

[0015]

The present invention is based on the Friedel
When a monoalkyl aromatic hydrocarbon is produced by reacting an olefin with an aromatic hydrocarbon in the presence of a Krafts catalyst, a reactor consisting of a pre-reaction section and a post-reaction section is set, and a Friedel-Crafts catalyst, Aromatic hydrocarbons and olefins are introduced into the pre-stage reaction section, and they are co-flowed in a mixed phase to carry out an alkylation reaction, and the olefin conversion rate in the rear section of the pre-stage reaction section is controlled to 30 to 99%. And the polyalkylaromatic hydrocarbon obtained by separating the effluent from the rear part of the latter-stage reaction part are introduced into the front part of the latter-stage reaction part, and mainly in the trans-stage reaction part. And a olefin conversion in the rear part of the latter-stage reaction section is set to 100% by an alkylation reaction, and a continuous production method of a monoalkyl aromatic hydrocarbon is provided.

As the aromatic hydrocarbon which is a raw material in the present invention, aromatic hydrocarbons such as benzene, toluene, xylene and phenol are used. As an olefin, carbon numbers such as ethylene, propylene and butylene have 2 to 2
There are 4 olefins. The choice of these olefins is made to provide the desired alkyl group on the monoalkyl aromatic hydrocarbon produced. For example, there are ethylbenzene and cumene as monoalkyl aromatic hydrocarbons. When ethylbenzene is produced, benzene and ethylene are used as raw materials, and when cumene is produced, benzene and propylene are used as raw materials. Further, it is preferable that the raw material olefin has a high purity, but in the present invention, it is not an essential condition,
Even if the raw material olefin contains an inert gas or paraffin in a gaseous state in a standard state, any olefin containing 5% by volume or more can be used.

When the monoalkyl aromatic hydrocarbon is produced, the molar ratio of olefin to aromatic hydrocarbon introduced into the reactor (hereinafter abbreviated as "E / B ratio") is:
0.3 to 1.0 is preferable. E / B at the inlet of the reactor is
The reaction is an equilibrium reaction and determines the reaction equilibrium composition at the outlet of the reactor as shown in FIG. 5, which greatly affects the entire equipment such as reaction and separation / recovery and the separation / recovery energy. When the E / B ratio is small, the amount of polyalkyl aromatic hydrocarbons recovered and introduced is small, but the amount of aromatic hydrocarbons recovered and introduced is large. The opposite is true when the E / B ratio is large, and there is an optimum value from the situation of each separated and recovered energy.

The polyalkyl aromatic hydrocarbon is a higher alkyl aromatic hydrocarbon having two or more alkyl groups, such as diethylbenzene, triethylbenzene and tetraethylbenzene in the production of ethylbenzene. The alkylation reaction is a reaction of introducing an alkyl side chain into an aromatic hydrocarbon. For example, there is a reaction of synthesizing ethylbenzene from benzene and ethylene as raw materials, and a reaction of synthesizing cumene from benzene and propylene as raw materials.

The transalkylation reaction is a reaction in which an alkyl group is mainly transferred from a polyalkyl aromatic hydrocarbon to an aromatic hydrocarbon to synthesize a monoalkyl aromatic hydrocarbon. For example, there is a reaction for synthesizing ethylbenzene from polyethylbenzene and benzene. The Friedel-Crafts catalyst in the present invention is a catalyst that promotes an alkylation reaction and a transalkylation reaction. For example, AlCl ₃ , SbCl ₅ , FeCl ₃ , TeC
l ₂ , SnCl ₄ , TiCl ₄ , TeCl ₄ , BiCl
₃ , Lewis acid catalysts such as ZnCl ₂ , silica, alumina,
There are solid acid catalysts such as zeolites. Zeolite catalysts include Y-type zeolite, X-type zeolite, ZSM-
5, ZSM-11, β-type zeolite, Ω-type zeolite and the like.

The reactor may be in the form of a container or tubular. In the case of a container, either a single one or a multi-tiered one is possible.
The setting of the first-stage reaction section and the second-stage reaction section is performed by supplying an alkylation catalyst, an aromatic hydrocarbon and an olefin, and further introducing a polyalkylaromatic hydrocarbon flowing out from the second-stage reaction section. And the alkylation reaction is carried out in the first-stage reaction section,
The transalkylation reaction is mainly performed in the latter-stage reaction section, and the alkylation reaction also proceeds.

In the reactor, a liquid phase mainly composed of aromatic hydrocarbons, a liquid phase or a catalyst existing in a solid phase suspended in the liquid phase,
And olefins dissolved in the gas or liquid phase,
The gas-liquid phase, the solid-liquid phase, or the gas-liquid solid phase reacts in parallel flow. Especially in a system in which a gas phase exists, when the gas phase and the liquid phase or the solid-liquid phase are countercurrent, the reaction liquid containing a small amount of aromatic hydrocarbons comes into contact with the olefin, and a heavy component is produced. This is because it becomes difficult to apply the present invention because it becomes easy and causes a decrease in olefin yield.

In the case of an upward co-current flow with one reactor as a container, a pre-stage reaction section 41 is provided at the lower part of the reactor, that is, the raw material supply side, and a post-stage reaction section 42 is provided at the upper part, that is, the reaction product take-out side. To provide. Inside the reaction vessel, a pore partitioning tool, for example, one or more perforated plates provided at the boundary between the two,
Filled with packing, or some combination of these can be used. Thus, the one-stage reactor can easily divide the front-stage reaction section 41 and the rear-stage reaction section 42.

As shown in FIG. 1, when the reactor is provided with a perforated plate, the reactor is separated from one perforated plate 34 immediately below the introduction of the polyalkyl aromatic hydrocarbon 16 and the lower part of the pre-reaction part 41 is provided. Then, the latter-stage reaction section 42 is formed on the upper part thereof. Although it is not necessary to install anything in each reaction section, it is preferable to further install the perforated plate 34. In the gas-liquid phase reaction, the former reaction section 4
When the perforated plate 34 is installed in the unit 1, the reaction amount per unit volume is improved. This is because in the alkylation reaction, the absorption of olefins from the gas phase containing mainly olefins to the liquid phase containing mainly aromatic hydrocarbons is rate-determining. The gas phase generally exists as bubbles in the liquid phase. Perforated plate 3
When passing through No. 4, since the interfacial area where the gas-liquid phase contacts is increased by being dispersed in finer bubbles having a larger diameter, the absorption rate of olefin is improved and the amount of alkylation reaction per unit volume is improved. Further, when the perforated plate 34 is installed in the post-reaction section 42, the transalkylation reaction amount per unit volume is improved, and the reaction product at the outlet can be brought closer to the composition in the reaction equilibrium state. This is because the flow is suppressed by the liquid phase reverse mixing in the system due to the porous plate.

The raw material aromatic hydrocarbon 12, the olefin 11, and the Friedel-Crafts catalyst 20 are continuously supplied to the first-stage reaction section 41. High-boiling substances such as catalyst, aromatic hydrocarbons, monoalkyl aromatic hydrocarbons, polyalkyl aromatic hydrocarbons, fluxes, and unreacted olefins from the first-stage reaction section 41 are all introduced into the second-stage reaction section 42. The effluent from the latter-stage reaction section 42, that is, the effluent 17 containing high boiling substances such as catalyst, aromatic hydrocarbons, monoalkyl aromatic hydrocarbons, polyalkyl aromatic hydrocarbons, and flux is overflowed, and the separation and recovery facility 23 is provided. And the product, a monoalkyl aromatic hydrocarbon 19, is taken out.

As a separation and recovery method, the catalyst is separated by sedimentation or a filter, and unreacted aromatic hydrocarbons and polyalkyl aromatic hydrocarbons and fluxes of reaction by-products are separated by distillation. At this time, the separated and recovered aromatic hydrocarbon 14 is returned to the front part of the front reaction part 41,
The polyalkyl aromatic hydrocarbon 16 is introduced into the front part of the rear reaction section 42. The post-reaction section 42 is located above the pre-reaction section 41 and is mainly used for aromatic carbonization such as a vapor phase of unreacted olefins from the pre-reaction section 41 and vapors of aromatic hydrocarbons evaporated by the reaction heat of the alkylation reaction. All of the liquid phase composed of hydrogen is introduced into the second-stage reaction section 42. Since it is in a gas-liquid two-phase flow here, the polyalkyl aromatic hydrocarbon from the separation and recovery system is sufficiently dispersed and mixed in the post-reaction section 42, and the transalkylation reaction is promoted.

The perforated plate usually has a hole diameter of 1 to 100 mm,
The aperture ratio is selected to be 1 to 30%. Here, if the pore diameter and the opening ratio are both smaller, the reverse mixing flow of the liquid phase can be suppressed and the reaction can be effectively performed. However, if it is too small, the strength of the perforated plate 34 must be increased due to the problem of clogging of solids or the like and the increase in pressure loss. It is selected according to the reaction conditions and reaction system used in this way.

In the case of charging the packing, as shown in FIG. 2, the reactor 21 is divided into the packing 35 immediately below the introduction of the polyalkylaromatic hydrocarbon 16 and the reaction section 41 at the lower part and the rear part at the upper part. The reaction part 42 is formed. It is not necessary to install anything in each reaction part, but it is preferable to further fill the filling material 35. The raw material and the recovered polyalkyl aromatic hydrocarbon 16 are introduced in the same manner as when the porous plate 34 of FIG. 1 is installed. The packing used here can be either an irregular packing such as Raschig ring or pole ring, or an ordered packing used in a distillation column or the like.

When using a plurality of reactors, FIG.
As shown in (1), the first reactor is the pre-reaction section 41, and the second reactor downstream thereof is the post-reaction section 42. Both are connected by piping. Here, if the mixed phase is cocurrent, it may be upward or downward. The raw materials are fed to the front part of the first reactor, and the introduction of the polyalkyl aromatic hydrocarbons 16 is carried out in the same manner as in the case of FIGS. 1 and 2.

When using a tubular reactor, the first half is set in the front reaction section 41 as shown in FIG.
The raw material is introduced into the front part of the front reaction part 41, and the latter half is set in the back reaction part 42. Introduction of the raw material and the recovered polyalkyl aromatic hydrocarbon is performed in the same manner as in FIGS. The reactor used in the present invention is not limited to these, and it is also possible to use, for example, a combination of some or all of them.

The olefin conversion rate is the ratio of olefins that contributed to the alkylation reaction per olefin introduced. When the introduced olefin is x mol / hour and the reacted olefin is y mol / hour, the olefin conversion rate is represented by (y / x) × 100%. These are calculated from the composition analysis and mass balance of the reaction solution by gas chromatography and the like.

Control of the olefin conversion rate is performed as follows. When the reaction temperature, the flow rate, and the catalyst concentration conditions are determined when designing the reactor, the olefin conversion rate can be increased by increasing the reaction time, that is, the reaction volume in the first-stage reaction section. On the contrary, the olefin conversion rate can be lowered by shortening the residence time. When increasing the olefin conversion rate depending on the operating conditions, increase the catalyst concentration,
This is achieved by raising the reaction temperature. On the contrary, when lowering the olefin conversion rate, the catalyst concentration is lowered or the reaction temperature is lowered.

Besides, the factors related to the reaction of the present invention are set as follows. The reaction temperature of the alkylation and transalkylation reaction is preferably 100 to 350 ° C. If the reaction temperature is too low, the reaction rate is lowered, the productivity is remarkably lowered, and the heat recovery temperature of the reaction heat is lowered, so that it cannot be effectively used. On the contrary, if it is too high, there are problems such as deterioration of the catalyst and reduction of yield. Here, the reaction temperatures of the alkylation reaction and the transalkylation reaction do not have to be the same, and any temperature can be used within this temperature range.

The reaction pressure is preferably 0 to 50 kg / cm ² gauge. The reaction pressure is preferably a pressure at which a liquid phase or a gas-liquid phase is formed. The present invention is basically based on the reaction in a gas-liquid phase. However, when an unreacted olefin is dissolved in a liquid phase in which an olefin is completely absorbed by an aromatic hydrocarbon or in a liquid phase of an aromatic hydrocarbon. Is no problem. When a Lewis acid catalyst is used as the Friedel-Crafts catalyst, it is necessary to make equipment such as a reactor and a heat exchanger with a corrosion-resistant material, so that olefin is mainly present in the gas phase. It is preferred to carry out the reaction at relatively low pressure. On the other hand, when the solid acid catalyst is used, the equipment does not need to be made of a corrosion resistant material, and therefore the reaction can be performed at a higher temperature and pressure than the Lewis acid catalyst. Therefore, the reaction rate may be either a gas-liquid solid phase or a solid-liquid phase, and the reaction heat can be recovered efficiently at a high temperature.

In the case of using a finely divided zeolite catalyst as an example of the production method using a solid acidic catalyst, the finely divided zeolite is suspended directly in the reaction solution in the pre-reaction section and subjected to the reaction, and then in the post-reaction section. It is introduced together with the alkylation reaction product, and the effluent thereof is separated by an ordinary separation device, for example, using a sedimentation separation tank or a filtration device, and is recycled to the reactor. Here, the secondary particle diameter of the solid acidic catalyst is 5 mm or less, preferably 0.1 micron or more and 50
It is 0 micron or less. The smaller the particle size is, the larger the surface area per unit volume of the catalyst is, so that the reaction rate is improved. However, there is no problem if the filtration equipment as disclosed in JP-A-5-68869 is used.

Next, the focus of the present invention will be described. The reaction mechanism will be described by taking an ethylbenzene synthesis reaction using aluminum chloride as a catalyst and using Ekrene and benzene as raw materials. This reaction is a typical Free
It is a del-Crafts reaction. First, in the alkylation reaction, ethylene gas is blown into liquid-phase benzene in the presence of aluminum chloride and a co-catalyst hydrochloric acid (or ethyl chloride). According to Hancock's reaction mechanism, this reaction is carried out by first using σ-BEAT (Sigma-bonded ethyl) with ethylene, aluminum chloride and hydrochloric acid.
e aluminum tetrachloride).

[0036]

[Chemical 2]

This σ-BEAT reacts with benzene to give π-BPCAT (π-bonded phenyleth).
yl carbonium aluminum tet
form a lacloride).

[0038]

[Chemical 3]

Through this, ethylbenzene is obtained.

[0040]

[Chemical 4]

Next, the transalkylation reaction reversibly produces ethylbenzene by dealkylation with polyethylbenzene and benzene or disproportionation reaction of polyethylbenzene.

[0042]

[Chemical 5]

Finally, the side reaction products are butylbenzene, flux and the like. Butylbenzene is formed by the dimerization of ethylene to form butene, which then reacts with benzene. At this time, it is σ-BEAT that contributes to the production of butene from ethylene.

[0044]

[Chemical 6]

Further, butylbenzene or the like is ethylene,
It reacts with butene, ethylbenzene, etc. and undergoes polycondensation to form a heavy substance called flux.

[0046]

[Chemical 7]

By clarifying the above reaction mechanism, it was found that there are the following two measures to improve the yield of ethylbenzene, that is, to reduce the production amount of heavy substances. (1) Suppression of heavy substances such as flux from butylbenzene. Specifically, it is achieved by dividing into two reactions, an alkylation reaction and mainly a transalkylation reaction. Here, the former is performed in the former reaction section and the latter is performed in the latter reaction section. The reason for suppressing the formation of heavy substances by this is that the polyethylbenzene recovered in the separation / recovery system is returned to the front part of the latter-stage reaction section, but butylbenzene and the like have a boiling point close to that of polyethylbenzene, so they are entrained with polyethylbenzene. It is returned to the front part of the rear reaction section. These react in a system in which a large amount of ethylene and the like are present, and polycondensate to generate a flux. Therefore, the formation of heavy substances is suppressed by dividing the reaction into a front reaction part containing a large amount of ethylene and a rear reaction part containing a small amount of ethylene, and returning polyethylbenzene to a system containing less ethylene, that is, a rear reaction part. (2) Prevention of ethylene dimerization. Specifically, it is achieved by reducing the excess catalyst in the ethylene-rich portion such as the first-stage reaction section. The reason is that the reaction rate of alkylation is generally much faster than the gas absorption rate of ethylene gas into a liquid phase mainly composed of benzene, so that the amount of catalyst required for the alkylation reaction is small. Therefore, reduce excess catalyst σ
-Reduce the amount of BEAT and preferentially react with benzene. This is because the production of butene due to the dimerization of ethylene is reduced and the production of butylbenzene is suppressed.

[0048]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

[0049]

Example 1 Aluminum chloride was used as a Friedel-Crafts catalyst, hydrogen chloride was used as a co-catalyst, ethylene and benzene were used as raw materials, and a continuous alkylation reaction and a continuous transalkylation reaction by re-introduction of recovered polyethylbenzene were used. An experimental experiment of synthetic ethylbenzene was performed.

As the apparatus used, one having a perforated plate 34 installed in one reactor 21 as shown in FIG. The reactor 21 has a vertical cylindrical shape with an internal volume of about 500 liters, and the perforated plates 34 can be attached and detached inside the reactor 21 so that the number of perforated plates 34, the aperture ratio, the hole diameter, the interval, etc. can be changed. I chose The raw material olefin 11, aromatic hydrocarbon 12, catalyst 20 supply nozzle are installed in the lower part of the apparatus, and the olefin and aromatic hydrocarbon gas extraction nozzles are installed in the upper part as described above, and the reaction is carried out in an upward parallel flow. It was Several nozzles for re-introducing the collected polyalkylbenzene, a nozzle for taking out reaction products and a sampling nozzle are installed so that the residence times of the pre-reaction part 41 and the post-reaction part 42 can be set separately, and gas and liquid at each point can be set. The composition was analyzed. Further, a pressure gauge and a thermometer were installed to measure reaction temperature and pressure. Also, a condenser 22 for gas from the upper part was installed to condense the gas and return it to the pre-stage reaction section 41. Separation and recovery of the effluent 17 is performed by first cooling with a cooler,
The catalyst and the reaction solution are separated by a filter, etc., and high boiling substances such as benzene, ethylbenzene, polyalkylbenzene and flux in the reaction solution are separated by an ordinary distillation apparatus. Was reintroduced into the second reaction section 42. At that time, the raw material and polyalkylbenzene were dispersed as uniformly as possible by using a sparger. All the reactors and condensers in contact with these catalysts and cocatalysts to the catalyst separator were made of corrosion-resistant metal.

The raw material ethylene was continuously and quantitatively supplied using a flow meter. Benzene was azeotropically dried (dehydrated) with a distillation apparatus and continuously quantitatively introduced with a pump. The aluminum chloride catalyst was continuously and quantitatively pumped as an ethylbenzene solution. The reaction conditions and results of the experiment are shown in Table 1.

From the experimental results and the experimental results shown in Table 4 of Comparative Example 1, the following can be said. (1) The reaction results of the alkylation reaction and the transalkylation reaction per unit volume by the method of the present invention, that is, the ethylbenzene yield and the reaction equilibrium arrival rate are improved. (2) The ethylbenzene selectivity is improved by increasing the ethylene conversion rate to a certain degree or more in the rear part of the front reaction section 41. (3) The ethylene conversion rate is improved by installing the perforated plate in the front reaction section 41. (4) By installing the perforated plate in the latter-stage reaction section 42, the reaction equilibrium arrival rate is improved, that is, the circulating benzene amount and the circulating polyethylbenzene amount are reduced.

[0053]

[Example 2] The same reaction experiment as in Example 1 was carried out except that a reactor filled with a packing material was used instead of the porous plate.
Here, as the filling material, a pole ring having a nominal size of 1 inch was used, and as shown in FIG. Table 2 shows the experimental conditions and results. From this, as in Example 1, high reaction results could be obtained.

[0054]

Example 3 The same reaction experiment as in Example 1 was carried out except that a zeolite catalyst was used as the catalyst. The experimental conditions and results are shown in Table 3. From this, as in Example 1, high reaction results could be obtained.

[0055]

Comparative Example 1 As shown in FIG. 6, a porous plate was not installed in the reactor 21, and polyethylbenzene was connected to the front of the reactor 21. Others were the same as in Example 1, and a reaction experiment was performed. The experimental conditions and results are shown in Table 4.

[0056]

[Table 1]

[0057]

[Table 2]

[0058]

[Table 3]

[0059]

[Table 4]

[0060]

The method for producing a monoalkylaromatic hydrocarbon according to the present invention returns the polyalkylaromatic hydrocarbon separated in the separation / recovery system to the front part of the second-stage reaction section 42 to thereby obtain a monoalkylaromatic hydrocarbon. Improve the yield of hydrogen. At this time, in the first-stage reaction section 41, the conversion rate of the olefin in the rear part is controlled to 30 to 99%, and the alkylation reaction is efficiently performed in the region where the olefin concentration in the gas phase is high. Further, when the transalkylation reaction is carried out in the latter-stage reaction section 42, at the same time, the alkylation reaction of the unreacted olefin from the alkylation reaction zone is substantially completed, thereby eliminating the loss of olefin. In this way, the yield and productivity of monoalkyl aromatic hydrocarbons can be improved at the same time.

Further, the alkylation reaction is usually the rate-limiting absorption of olefins in a system in which a gas phase exists. Therefore, when a porous plate or a packing is installed in the pre-reaction section 41,
Bubbles mainly containing olefin are atomized and dispersed, the contact interface area of gas and liquid is increased, the absorption rate of olefin is improved, and the alkylation reaction can be efficiently performed. Further, when a perforated plate or a packing material is installed in the latter-stage reaction section 42, since the reverse mixing flow of the liquid phase is suppressed, it is possible to easily approach the reaction equilibrium state. As described above, the productivity can be further improved by installing the perforated plate or the filler in each reaction section.

In the present invention, the catalyst may be either a Lewis acid catalyst or a particulate solid acid catalyst. For example, when a zeolite catalyst is used, the material of the reactor is smaller than that of the Lewis acid catalyst. Can be mild. In addition, since the two reaction sections of the front reaction section 41 and the rear reaction section 42 are set in one reactor, the operability is
It has good maintainability and can be installed and modified easily.

[Brief description of drawings]

FIG. 1 is a manufacturing method using a reactor in which a perforated plate is installed in the reactor. (For 4 perforated plates)

FIG. 2 is a production method using a reactor in which a reactor is filled with a packing. (When the packing is installed in two stages)

FIG. 3 is a production method using two reactors.

FIG. 4 is a production method using a tubular reactor.

FIG. 5 shows the equilibrium composition with respect to the molar ratio of ethyl group / benzene nucleus in the reactor in the synthesis of ethylbenzene by the alkylation reaction of ethylene and benzene using an aluminum chloride catalyst.

FIG. 6 is a manufacturing method using a conventional reactor.

[Explanation of symbols]

 11: Raw material olefin supply 11A: Ethylene 12: Raw material aromatic hydrocarbon supply 12A: Benzene 13: Condensate circulation (mainly aromatic hydrocarbon) 13A: Benzene 14: Aromatic hydrocarbon 14A: Benzene 15: Reactor front part 16: Polyalkyl aromatic hydrocarbon 16A: Polyethylbenzene 17: Effluent 18: Reactor rear part 19: Monoalkyl aromatic hydrocarbon 19A: Ethylbenzene 20: Catalyst (co-catalyst) 21: Reactor 22: Condenser 23: Separation Recovery equipment 31: sparger 32: sparger 33: sparger 34: perforated plate 35: packing 41: pre-reaction section 42: post-reaction section

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[Procedure amendment]

[Submission date] March 25, 1994

[Procedure Amendment 1]

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[Procedure Amendment 2]

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[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous process for producing a monoalkyl aromatic hydrocarbon, and more particularly to a novel process for producing a monoalkyl aromatic hydrocarbon by reacting an olefin with an aromatic hydrocarbon. Regarding an improved method. Monoalkyl aromatic hydrocarbons, such as ethylbenzene, have been used in large quantities to produce high-demand polystyrene as well as the styrene monomer that is the raw material for many copolymers.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

Since the aluminum chloride complex of the catalyst has a very strong corrosive property, the reactor 21 is made of a corrosion resistant material such as hastelloy or an inner lining such as acid brick. The effluent 17 other than gas in the reactor rear part 18 is neutralized and washed with water in order to remove the dissolved aluminum chloride and hydrochloric acid after separating the catalyst in the separation / recovery facility 23. Furthermore, benzene and ethylbenzene are separated in this order, and finally polyethylbenzene and heavy substances such as flux are separated. Here, polyethylbenzene is a higher alkylated benzene having two or more ethyl groups, such as diethylbenzene, triethylbenzene, and tetraethylbenzene. Polyethylbenzene 16A as well as the separated unreacted benzene is introduced into the reactor front part 15 and converted into ethylbenzene by the transalkylation reaction. Incinerate other heavy materials. In this way, ethylbenzene 19A was continuously produced.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

That is, the rate at which ethylene in the gas phase is absorbed into the liquid phase becomes a problem, and when the residence time is shortened, the absorption of ethylene gas becomes insufficient and ethylene is purged as an unreacted gas, so that the raw material ethylene fed is supplied. The yield of ethylbenzene per unit decreases. Therefore, it is possible to return unreacted ethylene to the reactor by using a recovery device such as a recycle compressor. However, the recovery device will be a facility made of corrosion-resistant material and will be used for driving an ethylene recycle compressor or the like. This is also undesirable because it requires energy. In order to complete the alkylation reaction in the alkylation zone where the absorption of ethylene gas is rate-determining, the residence time becomes long in the alkylation zone.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

Next, even in the reaction in the liquid single phase, in order to complete the alkylation reaction in the alkylation zone, the ethylene concentration in the solution becomes very low immediately before the reaction is completed, and the alkylation zone is also reduced. The residence time at is longer.
Thus, nothing has been solved about the low productivity in the alkylation zone.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

The present invention provides a monoalkyl aromatic hydrocarbon which produces a small amount of a heavy product and has a high yield or selectivity of a monoalkyl aromatic hydrocarbon and which has a high productivity in an alkylation reaction and a transalkylation reaction. A continuous manufacturing method is provided.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

When the monoalkyl aromatic hydrocarbon is produced, the molar ratio of olefin to aromatic hydrocarbon introduced into the reactor (hereinafter abbreviated as "E / B ratio") is:
0.3 to 1.0 is preferable. The E / B ratio at the inlet of the reactor determines the reaction equilibrium composition at the outlet of the reactor as shown in FIG. 5, and has a great influence on the entire equipment such as reaction and separation / recovery and the separation / recovery energy. When the E / B ratio is small, the amount of polyalkyl aromatic hydrocarbons recovered and introduced is small, but the amount of aromatic hydrocarbons recovered and introduced is large. The opposite is true when the E / B ratio is large, and the optimum value is selected from the situation of each separation and recovery energy.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Name of item to be corrected] 0023

[Correction method] Change

[Correction content]

As shown in FIG. 1, when the reactor is provided with a perforated plate, the reactor is separated from one perforated plate 34 immediately below the introduction of the polyalkyl aromatic hydrocarbon 16 and the lower part of the pre-reaction part 41 is provided. Then, the latter-stage reaction section 42 is formed on the upper part thereof. Although it is not necessary to install anything in each reaction section, it is preferable to further install the perforated plate 34. In the gas-liquid phase reaction, the former reaction section 4
When the perforated plate 34 is installed in the unit 1, the reaction amount per unit volume is improved. This is because in the alkylation reaction, the absorption of olefins from the gas phase containing mainly olefins to the liquid phase containing mainly aromatic hydrocarbons is rate-determining. The gas phase generally exists as bubbles in the liquid phase. Perforated plate 3
When passing through No. 4, since the interfacial area where the gas-liquid phase contacts is increased by being dispersed in finer bubbles having a larger diameter, the absorption rate of olefin is improved and the amount of alkylation reaction per unit volume is improved. Further, when the perforated plate 34 is installed in the post-reaction section 42, the transalkylation reaction amount per unit volume is improved, and the reaction product at the outlet can be brought closer to the composition in the reaction equilibrium state. This is because the reverse mixing flow of the liquid phase in the system is suppressed by the porous plate.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

When using a tubular reactor, the first half is set in the front reaction section 41 as shown in FIG.
The raw material is introduced into the front part of the front reaction part 41, and the latter half is set in the back reaction part 42. The introduction of the raw material and the recovered polyalkyl aromatic hydrocarbon is carried out in the same manner as in FIGS. The reactor used in the present invention is not limited to these, and it is also possible to use, for example, a combination of some or all of them.

[Procedure Amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0033

[Correction method] Change

[Correction content]

The reaction pressure is preferably 0 to 50 kg / cm ² gauge. The reaction pressure is preferably a pressure at which a liquid phase or a gas-liquid phase is formed. The present invention is basically based on the reaction in a gas-liquid phase. However, when an unreacted olefin is dissolved in a liquid phase in which an olefin is completely absorbed by an aromatic hydrocarbon or in a liquid phase of an aromatic hydrocarbon. Is no problem. When a Lewis acid catalyst is used as the Friedel-Crafts catalyst, it is necessary to make equipment such as a reactor and a heat exchanger with a corrosion-resistant material, so that olefin is mainly present in the gas phase. It is preferred to carry out the reaction at relatively low pressure. On the other hand, when the solid acid catalyst is used, the equipment does not need to be made of a corrosion resistant material, and therefore the reaction can be performed at a higher temperature and pressure than the Lewis acid catalyst. Therefore, the reaction system may be either a gas-liquid solid phase or a solid-liquid phase, and the reaction heat can be recovered efficiently at high temperature.

[Procedure Amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0040

[Correction method] Change

[Correction content]

[0040]

[Chemical 4]

[Procedure Amendment 12]

[Document name to be amended] Statement

[Correction target item name] 0060

[Correction method] Change

[Correction content]

[0060]

The method for producing a monoalkylaromatic hydrocarbon according to the present invention returns the polyalkylaromatic hydrocarbon separated in the separation / recovery system to the front part of the second-stage reaction section 42 to thereby obtain a monoalkylaromatic hydrocarbon. Improve the yield of hydrogen. At this time, in the first-stage reaction part 41, the conversion rate of the olefin in the rear part is controlled to 30 to 99%, and the alkylation reaction is efficiently performed in the region where the olefin concentration is high. Further, in the latter-stage reaction section 42, the transalkylation reaction is performed, and at the same time, the alkylation reaction of the unreacted olefin from the alkylation reaction zone is substantially completed, thereby eliminating the loss of olefin. In this way, the yield and productivity of monoalkyl aromatic hydrocarbons can be improved at the same time.

Claims (8)

[Claims] 1. In the presence of Friedel-Crafts catalyst,
When a monoalkyl aromatic hydrocarbon is produced by reacting an aromatic hydrocarbon with an olefin, a reactor consisting of a pre-reaction section and a post-reaction section is set to remove Friedel-Crafts catalyst, aromatic hydrocarbon and olefin. The mixture was introduced into the front-stage reaction section and allowed to flow in parallel in a mixed phase to carry out an alkyl reaction, and the olefin conversion rate in the rear section of the front-stage reaction section was 30 to 99.
%, And a polyalkyl aromatic hydrocarbon obtained by separating the effluent from the former reaction part and the effluent from the latter part of the latter reaction part is introduced into the latter part of the latter part reaction part, A method for continuously producing a monoalkylaromatic hydrocarbon characterized in that a transalkylation reaction is mainly carried out in the latter-stage reaction section, and the olefin conversion rate in the latter-half section of the latter-stage reaction section is 100% depending on the alkylation reaction. . 2. The continuous production method for monoalkyl aromatic hydrocarbons according to claim 1, wherein one container is set in the front reaction section and the rear reaction section by means of the pore partitioning tool. 3. The continuous production method for monoalkyl aromatic hydrocarbons according to claim 2, wherein the pore partitioning tool is a porous plate. 4. The method for continuously producing a monoalkyl aromatic hydrocarbon according to claim 2, wherein the pore partitioning member is a filling material. 5. The continuous production method for monoalkyl aromatic hydrocarbons according to claim 1, wherein the front-stage reaction section and the rear-stage reaction section are set by a plurality of vessels connected by piping. 6. The reactor is tubular, and the polyalkyl aromatic hydrocarbon is introduced in the middle of the tubular to make the front part of the tubular part a front stage reaction part and the rear part of the tubular part a back stage reaction part. The method for continuously producing monoalkyl aromatic hydrocarbons according to claim 1. 7. The continuous production method of monoalkyl aromatic hydrocarbons according to claim 1, wherein a Lewis acid catalyst is used as the Friedel-Crafts catalyst and the reaction is carried out in a mixed phase of gas and liquid. 8. The method for continuously producing monoalkyl aromatic hydrocarbons according to claim 1, wherein a solid acid catalyst is used as the Friedel-Crafts catalyst and the reaction is carried out in a solid-liquid or solid-gas mixed phase.