KR100653563B1 - A method for production of styrene - Google Patents

Abstract

 The present invention relates to a process for producing styrene by dehydrogenating ethylbenzene, and more particularly, to a process for producing styrene from dehydrogenation of ethylbenzene at a relatively low temperature of 100-400 ° C To a process for producing styrene by dehydrogenating ethylbenzene.

According to the styrene production method of the present invention, it is not necessary to use high-temperature steam as a diluent by using the iron oxide-based catalyst used for dehydrogenating the existing ethylbenzene and a new catalyst having a synergy effect, Since styrene can be produced at a lower temperature than the method of producing styrene by dehydrogenating ethylbenzene in the presence of a catalyst, the present invention can simplify the production process of styrene and reduce the cost, and at a remarkably high yield There is an excellent effect that styrene can be produced by dehydrogenation of ethylbenzene.

Description

 [0001] The present invention relates to a method for producing styrene,

The present invention relates to a process for producing styrene by dehydrogenating ethylbenzene, and more particularly, to a process for producing styrene from dehydrogenation of ethylbenzene at a relatively low temperature of 100-400 ° C A process for producing styrene by dehydrogenating ethylbenzene and styrene produced by the process.

Generally, styrene is widely used as a raw material for producing various polymers such as polystyrene, ABS resin and synthetic rubber such as synthetic rubber, and is one of important raw materials of the chemical industry, whose production amount is increasing every year due to its use.

Commercial styrene production methods known so far include a method of dehydrogenating ethylbenzene at a high temperature of 600 ° C or higher in the presence of an iron oxide catalyst and a method of reacting ethylbenzene with oxygen to produce peroxide of ethylbenzene and reacting it with propylene, Oxide and dehydrating phenylethanol again to prepare styrene.

First, the method of dehydrogenating ethylbenzene in the presence of an iron oxide-based catalyst, which is the most common method used for commercial production of styrene, was initially poor in performance of the catalyst, resulting in low selectivity and conversion rate and short catalyst life, As a result of efforts to improve the catalyst, a catalyst having advantages such as high selectivity and conversion rate has been developed as shown in U.S. Patent No. 6191065, U.S. Patent No. 6465704, U.S. Patent No. 5689023, and the like. However, in the method of producing styrene by the dehydrogenation reaction of ethylbenzene in the presence of an iron oxide catalyst, the thermodynamic equilibrium is basically disadvantageous to styrene, and a steam having a higher molar ratio than ethylbenzene should be used. Therefore, when the molar ratio of ethylbenzene to steam is low, decomposition of ethylbenzene occurs and coke is formed on the catalyst, shortening the lifetime of the catalyst, lowering the selectivity, and using a lot of energy.

In order to overcome this fundamental problem, as shown in US Pat. No. 6,586,360 and US Pat. No. 5,866,737, much research has been conducted on the oxidative dehydrogenation reaction of ethylbenzene. Compared with the simple dehydrogenation reaction of ethylbenzene, the oxidative dehydrogenation reaction that generates water is thermodynamically favorable to styrene, so that the styrene yield can be expected at a relatively low temperature theoretically. However, it has been difficult to develop a catalyst having a high selectivity because it is difficult to control the reaction by using oxygen, which is a strong oxidizing agent.

In order to overcome the difficulties of this oxidative dehydrogenation reaction, the styrene production process which is a process of producing propylene and styrene together, that is, a process of producing ethylbenzene peroxide by reacting ethylbenzene with oxygen and reacting it with propylene to produce phenyl ethanol and propylene oxide And dehydrating phenylethanol again to prepare styrene. This method overcomes the difficulties of the dehydrogenation reaction and the oxidative dehydrogenation reaction of ethylbenzene, but requires a three-step reaction. Since propylene oxide is blended, it is disadvantageous in that the production amount of styrene must be controlled according to the market conditions of propylene oxide .

Accordingly, there have been many demands in the art for a method of producing styrene without such problems.

In order to overcome the above problems, the inventors of the present invention have been studying a method of overcoming the above difficulties and producing styrene in a one-step reaction at a low temperature. Among the iron oxide-based catalysts and compounds having a quinone structure Styrene can be prepared by reacting ethylbenzene at a temperature of 100 ° C to 400 ° C in the presence of the catalyst system in which the coexisting catalyst is present.

Accordingly, an object of the present invention is to provide a process for producing styrene at a low temperature, compared to a process for producing styrene by dehydrogenating ethylbenzene in the presence of a conventional iron oxide catalyst without using high temperature water vapor as a diluent, And at the same time to reduce costs, and to provide styrene produced by the above method.

Another object of the present invention is to provide a process for producing dehydrogenation of ethylbenzene, which is used for dehydrogenating ethylbenzene to produce dehydrogenation of ethylbenzene to produce styrene at a significantly low temperature, The present invention provides a method for producing styrene which can produce styrene at a remarkably high yield.

In order to accomplish the above object, the present invention provides a process for producing ethylbenzene by dehydrogenation reaction at a reaction temperature of 100 to 400 ° C in the presence of an iron oxide catalyst and a catalyst system in which a compound of Formula 1 or Formula 2 having a quinone structure coexists And the styrene is reacted with the styrene.

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( 여기서, R1, R2, R3, R4는 각각 수소, 알킬, 알케닐, 할로겐, 시안기 등의 작용기를 나타내는 것으로 각각은 같을 수도 있고 다를 수도 있다.)

(Wherein R1, R2, R3, and R4 each represent a functional group such as hydrogen, alkyl, alkenyl, halogen, or a cyano group, and each may be the same or different)

The compound of formula 1 or 2 is characterized by being benzoquinone, anthraquinone or a derivative thereof.

The iron oxide catalyst is characterized in that the Fe compound catalyst contains a K compound.

The dehydrogenation reaction of ethylbenzene is characterized in that water vapor is not used as a diluent.

Hereinafter, the present invention will be described.

The present invention relates to a process for producing styrene by dehydrogenating ethylbenzene, and more particularly, to a process for producing styrene by the dehydrogenation of ethylbenzene without using steam at high temperature as a diluent and a compound having a quinone structure such as the following structural formula 1 or 2 The present invention relates to a new method for producing styrene by dehydrogenating ethylbenzene at a relatively low temperature of 100 ° C to 400 ° C in the presence of a catalyst system.

R 1, R 2, R 3 and R 4 in the following structural formula 1 or 2 each represent a functional group such as hydrogen, alkyl, alkenyl, halogen or cyanide, and may be the same or different, Is preferably benzoquinone, anthraquinone or a derivative thereof in consideration of the synergistic effect with the iron oxide-based catalyst.

Next, the iron oxide catalyst used in the present invention means a metal oxide catalyst containing iron used for the dehydrogenation reaction of ethylbenzene. The iron oxide catalyst may be prepared by known coprecipitation, impregnation, cracking, mechanical mixing, or the like. The iron oxide catalyst prepared by any one of the above methods is extruded into a desired shape, It is preferable to use it by baking at a temperature of 1200 deg.

Here, the iron oxide catalyst is not limited as long as it is a known iron oxide catalyst used in a conventional styrene production process, but preferably the Fe compound catalyst is composed to contain a K compound.

Hereinafter, the technical structure of the present invention will be described in more detail with reference to examples. However, these embodiments are for illustrative purposes only, and the present invention is not limited to these embodiments.

Example 1

A 500 cc autoclave was charged with 250 g of ethylbenzene and 50 g of an iron oxide catalyst (77% Fe 2 O 3, 9.6% K 2 O, 7% CeO 2, MgO 2 %, CaO 2%, and MoO 3 2.4%) and benzoquinone corresponding to 5% by weight of ethylbenzene were introduced, and the dehydrogenation reaction was carried out under the conditions of a reaction temperature of 250 ° C., a reaction pressure of 12 atm, and a reaction time of 3 hours And the number of moles of the resultant styrene was measured. The results are shown in Table 1.

Example 2

Benzoquinone was introduced into the reactor corresponding to 10% by weight of ethylbenzene.

Comparative Example

Was carried out in the same manner as in Example 1, except that benzoquinone was not introduced into the reactor at all.

Benzoquinone (added amount relative to ethylbenzene,%)  The iron oxide catalyst (g)  Production of styrene (mmol) Example 1 5 50 2.865 Example 2 10 50 3.126 Comparative Example No additives 50 0

From Table 1, it can be seen that when the reaction conditions such as the present invention, namely, the reaction temperature is 250 ° C, the dehydrogenation reaction of ethylbenzene does not occur at all when benzoquinone is not added to the iron oxide catalyst, , It can be seen that styrene is produced at a considerably high yield when benzoquinone is added.

It will be apparent to those skilled in the art that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

As described above, according to the styrene production method of the present invention, it is not necessary to use high-temperature steam as a diluent by using the iron oxide-based catalyst used for dehydrogenating the existing ethylbenzene and a new catalyst having a synergy effect concurrently , Styrene can be produced at a lower temperature than the conventional method of producing styrene by dehydrogenating ethylbenzene in the presence of an iron oxide catalyst, and thus the present invention can simplify the styrene production process and reduce costs But there is an excellent effect that styrene can be produced by dehydrogenation of ethylbenzene at a remarkably high yield.

Claims (5)

Ethylbenzene is subjected to a dehydrogenation reaction at a reaction temperature of 100 to 400 DEG C in the presence of a catalyst system in which an iron oxide-based catalyst and a compound having a structural formula 1 or a structural formula 2 having a quinone structure coexist.

(Wherein R1, R2, R3, and R4 each represent a functional group such as hydrogen, alkyl, alkenyl, halogen, or a cyano group, and each may be the same or different) delete The method for producing styrene according to claim 1, wherein the compound of Formula 1 or Formula 2 is any one of benzoquinone, anthraquinone, and derivatives thereof. The method for producing styrene according to claim 1 or 3, wherein the iron oxide catalyst comprises a K compound. delete