JPH11193253A - Direct production of styrene - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an efficient one-step process of direct styrene production from benzene and ethylene and/or ethane by using a zeolite catalyst ion- exchanged with a specific metal element. SOLUTION: Over a zeolite catalyst ion-exchanged with metal elements selected from the group consisting of Ga, Ge, As, In, Sn, Sb, Tl, Pb and Bi, the catalytic reactions between benzene and ethylene and or ethane are carried out under the gas-phase conditions. In a preferred embodiment, a ZSM zeolite having the MFI structure can be selected as a zeolite catalyst. The zeolite used for the ion exchange bears an alkali metal cation because the ion-exchange rate can be increased. In this direct styrene production, the reactions are carried out at the molar ratio of benzene to ethylene and/or ethane of 2/1-10/1, the weight space velocity of 0.2-5, at reaction temperature of 500-650 deg.C under the pressure of 0.1-3 kg/cm<2> calculated as a partial pressure of the starting gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to styrene, which is useful as a monomer material for synthetic resins and synthetic rubbers such as polystyrene, styrene / butadiene rubber, acrylonitrile / butadiene / styrene and unsaturated polyester, and benzene and ethylene and / or ethane. And a method for manufacturing in one step.

[0002]

2. Description of the Related Art An industrial method for producing styrene is a so-called two-step production method in which ethylbenzene is produced from benzene and ethylene by an alkylation reaction, and styrene is produced from ethylbenzene obtained by separation and purification by dehydrogenation. Has been done on a large scale. The method for producing ethylbenzene corresponding to the former stage includes an alkylation reaction under a liquid phase condition using a Friedel-Crafts type catalyst such as aluminum chloride or phosphoric acid, and a liquid phase reaction using an acid type zeolite catalyst such as Y, β or ZSM-5. Alternatively, an alkylation reaction under gas phase conditions is typical. The reaction is ΔH (300K) =-27.2Kcal / mo.
1 violent exothermic reaction. To increase the yield of ethylbenzene, it is generally employed to carry out a transalkylation reaction after the alkylation reaction. On the other hand, the styrene production method corresponding to the latter stage is typically a dehydrogenation reaction under a gas phase condition using steam as a medium and an iron oxide system such as Fe2O3-Cr2O3-K2CO3 as a catalyst. The reaction is ΔH (300K) = 28.1Kcal / mo.
This is a vigorous endothermic reaction, and a high temperature condition of 500 ° C. or more is adopted on the reaction equilibrium. Although the two-stage styrene production method via ethylbenzene production is still being improved at present, the production technology has reached an almost completed area.

As a method for producing styrene, there is a possibility that a significant industrial value may be generated over the above-mentioned conventional production method, and the styrene and the raw materials benzene and ethylene are produced in a one-step reaction without going through ethylbenzene production. This is a simple method for producing styrene. However, a technique showing significance in the production technique of the one-step reaction has not been disclosed so far.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing styrene directly in a one-step reaction using benzene and ethylene, and furthermore, benzene and ethane as raw materials, and a catalyst used therefor. And

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems. As a result, if a zeolite catalyst ion-exchanged with a specific metal element is used, benzene and ethylene can be further reacted. Have found that styrene can be efficiently produced even by reacting benzene with ethane, and have completed the present invention.

That is, the present invention relates to the following. (1) Ga, Ge, As, In, Sn, Sb, Tl, P
b. Direct styrene production process comprising contacting benzene with ethylene and / or ethane under gas phase conditions in the presence of a zeolite catalyst ion-exchanged with at least one metal element selected from b and Bi. (2) Ion exchange Is carried out using a zeolite having an alkali metal cation.
The direct production method of styrene according to 1. (3) The method for directly producing styrene according to the above (1) or (2), wherein the zeolite is a ZSM zeolite having an MFI structure.

Hereinafter, the present invention will be described in more detail. The catalyst of the present invention comprises Ga, Ge, As, In, Sn, Sb, T
It is a zeolite species ion-exchanged with at least one metal element selected from l, Pb, and Bi.

[0008] The zeolite species is not particularly limited as long as it is a zeolite that can be used as a catalyst. Examples are X-type faujasite, Y-type faujasite, A, L, β
(Beta), offretite, erionite, mordenite, ferrierite, ZSM-5, ZSM-8, ZSM
-11, ZSM-12, ZSM-22, ZSM-23,
Crystalline aluminosilicates such as ZSM-35, ZSM-38, ZSM-48, and silicalite are used. Si
The molar ratio of O2 / Al2O3 can be selected from the range of about 5 to 1000, preferably about 10 to 200. Also, B, Ga, Ti, Fe, Cu, Ag,
Metalloaluminosilicate or metallosilicate containing elements such as Cr, Ge, and P can also be used. Among these zeolite species, more preferred zeolite species are I
ZSM-based aluminosilicates, metalloaluminosilicates, and metallosilicates represented by the skeleton structure type and the MFI structure type according to the recommendations of UPAC.

In the catalyst of the present invention, at least one specific metal element is introduced into the above zeolite species by an ion exchange method. Specific metal elements are Ga, Ge, As, In, S
at least one selected from n, Sb, Tl, Pb and Bi
It is a seed element.

As a method for introducing at least one specific metal element into the zeolite species, there are known introduction methods such as an ion exchange method, an impregnation method and a kneading method, and any of these methods can be adopted. The ion exchange method is used. The zeolite species obtained by introducing at least one specific metal element by an ion exchange method, when used in the catalyst of the present invention, compared with the zeolite species of the impregnation method or the kneading method, benzene and ethylene and / or It increases the conversion of ethane and the selectivity of the resulting styrene. For this reason, zeolite species employing the ion exchange method are superior to zeolite species employing other methods as catalysts in the direct styrene production process of the present invention.

As the metal compound used for the ion exchange method, metal salts such as nitrates, sulfates, hydrochlorides, acetates, oxalates and the like are used. On the other hand, zeolite subjected to the ion exchange method has protons, ammonium ions, and Na as cation species.
Alkali metal cations such as K, alkaline earth metal cations such as Mg and Ca, tetraalkylammoniums
Those having one or more cations derived from a template (crystallization agent) such as alkylamines and diamines are used. Further, a material in which Al, B, Ga, or the like existing in the skeleton during the process of zeolite synthesis or post-treatment is partially desorbed from the skeleton and partially occupies a cation site is also used. In the ion exchange method, some or all of these cations are exchanged. In the partial exchange, these cation species coexist with the transition metal element, but there is no problem as a catalyst. In the ion exchange method, a cation species capable of increasing the ion exchange rate is an alkali metal cation. Even when a catalyst is used, the alkali metal cation exhibits favorable catalytic performance in the presence of a specific metal.

[0012] The ion exchange method can be performed according to a known method, typically using an aqueous solvent. The relationship between the usage ratio of zeolite and metal salts in the ion exchange treatment is as follows:
It is usually in the range of 0.1 to 100, expressed as the ratio of the total number of moles of metal salts to the exchange capacity of zeolite. In general, a metal salt containing a metal to be introduced is dissolved in an aqueous solvent, and zeolite is charged into the aqueous solution and allowed to stand or stirred to perform ion exchange. The concentration of the aqueous metal salt solution when the metal salt to be introduced is dissolved in an aqueous solvent varies depending on the type of the metal salt used, and is usually 0.0001 to 10 mol / li.
ter. The pressure at the time of the ion exchange treatment is usually performed at normal pressure, but may be performed under reduced pressure or under increased pressure. When the aqueous solution temperature at the time of the ion exchange treatment is normal pressure, 0 to 100 ° C. is usually used. The ion exchange treatment time is usually 0.1 to 100 hours. Further, the ion exchange treatment may be performed not only once but also repeatedly. After the completion of the ion exchange treatment, the catalyst can be washed with water, dried, and optionally heated or calcined to be used as a catalyst. The ratio of the introduced metal to the zeolite in the catalyst thus obtained is usually in the range of 0.1 to 10% by weight, depending on the type of zeolite and the method of ion exchange. This concentration range is not strict,
When the content is less than 0.1% by weight, the catalyst performance is not sufficient, and when the content is more than 10% by weight, it is difficult to improve the catalyst performance as compared with the amount of metal used.

These zeolites can be used as a catalyst as they are. However, in order to improve the physical properties of the catalyst, such as by imparting strength, the zeolite powder is converted to alumina, silica, silica / alumina, titania, diatomaceous earth, or natural clay. It can be used by mixing with various inorganic oxide binders. In this case, the content of the inorganic oxide binder in the catalyst is 1
It may be within the range of ~ 99% by weight, and generally 10 ~ 99% by weight.
It may be in the range of 90% by weight, more usually 20-30% by weight. The catalyst obtained by mixing the zeolite and the inorganic oxide binder is used after being formed into tablets or extrudates having a desired size and shape by a known method.

The raw material benzene used in the production method of the present invention is used after previously removing the water content thereof to about 200 ppm by weight or less and further to about 100 ppm by weight or less in order to suppress the activity deterioration of the zeolite catalyst. Is preferred. The olefin or alkane having two carbon atoms, which is the other raw material, is typically a purified high-purity ethylene gas or ethane gas, or a mixed gas thereof. Furthermore,
A hydrocarbon mixture of lower purity, for example, crude ethylene gas having an ethylene concentration of about 30 to 90% by volume generated from a naphtha pyrolysis furnace or off-gas having an ethylene concentration of about 10 to 20% by volume generated from a catalytic cracking furnace (FCC) Alternatively, ethane-rich gas from natural gas can be used.

The type of the reactor according to the present invention is not particularly limited, and various types of reactors can be used. Typically, a flow-type fixed bed reactor or fluidized bed reactor can be employed. Both benzene and two-carbon olefins and alkanes exist in the gas phase in the reactor. In the case of a vertical flow reactor, the flow direction of both benzene vapor and two-carbon olefins and alkanes With the ascending co-current method,
Either a descending cocurrent method or a countercurrent method can be adopted. These reactors may be a single catalyst bed or multiple catalyst beds. Also, multiple reactors in parallel or in series may be used. Since the reaction is slightly endothermic, a reactor which easily gives heat is employed.

The amount of benzene and ethylene (and / or ethane) supplied to the reactor is preferably supplied in the presence of a stoichiometric excess of benzene in order to prevent catalyst deterioration. The supply molar ratio of benzene to ethylene (and / or ethane) is from 1: 1 to 20: 1, preferably from 2: 1 to 1
It can be selected from the range of 0: 1. The reaction temperature is about 450 ° C to 700 ° C, preferably about 500 ° C to 650 ° C.
It is in the range of ° C. The reaction pressure is about 0.1 to 10 kg / cm ² , preferably about 0.1 to 3 in terms of a partial pressure of a raw material gas composed of benzene vapor and ethylene (and / or ethane).
kg / cm ² . As the diluent gas, not only the accompanying gas contained in ethylene (and / or ethane) but also an inert or less active gas such as nitrogen or carbon dioxide may be positively added. The weight hourly space velocity (WHSV) of ethylene (and / or ethane) ranges from about 0.1 to 10, preferably from about 0.2 to 5. However, these reaction conditions are not individually taken as optimum values but are interrelated.

After cooling, the product after the reaction is separated into a gas component and a liquid component, and the liquid component is supplied to a purification step in which a commonly known distillation operation is carried out to obtain a target styrene. The unreacted benzene fraction separated by the distillation operation is returned to the reactor and can be recycled. The ethylbenzene fraction produced as a by-product can be taken out as a by-product or returned to the reactor and recycled.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to examples. Note that the present invention is not limited to these examples unless it exceeds the gist.

[0019]

(Example 1) ZSM-5 type zeolite (SiO ₂ / Al ₂ O ₃ =) prepared by hydrothermal synthesis, filtration, washing, drying and calcining in air at 550 ° C. by a known method.
48) with 1N aqueous nitric acid solution (10 ml / g-zeolite)
Exchanged at room temperature for 3 hours, filtered and washed with water at 110 ° C
To prepare H ⁺ type ZSM-5. This H ⁺ type Z
SM-510 g in 4.3 wt% gallium nitrate aqueous solution 10
Using 0 g, the mixture was stirred at 80 ° C. for 2 hours to perform an ion exchange treatment. After filtration, washing with water and drying at 110 ° C., 55
By calcining at 0 ° C., an H ⁺ type zeolite containing gallium was prepared. Subsequently, after pressure molding, pulverization is performed, and 0.6-1.
A catalyst sieved to 0 mm was prepared. As a result of analysis with an X-ray microanalyzer (EPMA), it contained 0.4 wt% of gallium. Inner diameter 15mm, length 450
3 g of the catalyst was charged into a 1 mm quartz reactor, and introduced at 600 ° C. and normal pressure at a ratio of benzene / ethylene = 10/1 at an ethylene space velocity of 1.0 h ⁻¹ and reacted for 1 hour. The gas composition after one hour was analyzed by gas chromatography.
Was obtained.

(Example 2) ZSM-5 used in Example 1
Type zeolite _{(SiO 2 / Al 2 O 3} = 48) 3.4
N sodium chloride aqueous solution (10 ml / g-zeolite)
Ion exchange at 90 ° C for 3 hours in water, 110 ° C after washing with filtered water
To prepare Na ⁺ type ZSM-5. This Na ⁺
10 g of type ZSM-5 was subjected to an ion exchange treatment at 60 ° C. for 2 hours using 100 g of a 3.7 t% indium chloride aqueous solution. The same treatment and molding as in Example 1 were performed to prepare a Na ⁺ -type ZSM-5 catalyst containing indium. When the catalyst was analyzed with an X-ray microanalyzer (EPMA),
It contained 0.4% indium. The reaction was carried out in the same reactor, method, and conditions as in Example 1, and the results in Table 1 were obtained.

(Example 3) 10 g of Na ⁺ type ZSM-5 prepared in Example 2 was added to an 8 wt% aqueous solution of thallium nitrate 10
Using 0 g, an ion exchange treatment was performed at 60 ° C. for 2 hours. The same treatment and molding as in Example 1 were performed to prepare a Na ⁺ -type ZSM-5 catalyst containing thallium. When the catalyst was analyzed by an X-ray microanalyzer (EPMA), it contained 0.3% of thallium. The reaction was carried out in the same reactor, method, and conditions as in Example 1, and the results in Table 1 were obtained.

Example 4 10 g of Na ⁺ type ZSM-5 prepared in Example 2 was added to 100 g of a 5 wt% tin chloride aqueous solution.
Was used to perform an ion exchange treatment at 60 ° C. for 2 hours. When the catalyst was analyzed with an X-ray microanalyzer (EPMA), it contained 0.4% tin. The reaction was carried out in the same reactor, method, and conditions as in Example 1, and the results in Table 1 were obtained.

Example 5 10 g of Na ⁺ type ZSM-5 prepared in Example 2 was subjected to ion exchange treatment at 60 ° C. for 2 hours using 100 g of an 8 wt% aqueous solution of lead nitrate. Na ⁺ type ZSM containing lead by performing the same processing and molding as in Example 1.
-5 catalyst was prepared. When the catalyst was analyzed with an X-ray microanalyzer (EPMA), it contained 0.3% of lead. The reaction was carried out in the same reactor, method and conditions as in Example 1,
The results in Table 1 were obtained.

Example 6 10 g of Na ⁺ type ZSM-5 prepared in Example 2 was subjected to ion exchange treatment at 60 ° C. for 2 hours using 100 g of a 7 wt% antimony tartrate aqueous solution. The same treatment and molding as in Example 1 were performed to prepare a Na ⁺ -type ZSM-5 catalyst containing antimony. When the catalyst was analyzed with an X-ray microanalyzer (EPMA), it contained 0.3% of antimony. The reaction was carried out in the same reactor, method, and conditions as in Example 1, and the results in Table 1 were obtained.

Example 7 10 g of Na ⁺ type ZSM-5 prepared in Example 2 was subjected to an ion exchange treatment at 60 ° C. for 2 hours using 100 g of 7 wt% bismuth nitrate. The same treatment and molding as in Example 1 were performed to prepare a Na ⁺ -type ZSM-5 catalyst containing bismuth. When the catalyst was analyzed with an X-ray microanalyzer (EPMA), bismuth was reduced to 0.
It contained 3%. The reaction was carried out in the same reactor, method, and conditions as in Example 1, and the results in Table 1 were obtained.

[0026]

[Table 1] (Example 8) Na ⁺ type ZSM-5 prepared in Example 2
10 g was stirred at 80 ° C. for 2 hours using 100 g of a 4.3 wt% gallium nitrate aqueous solution to perform ion exchange treatment.
The same processing and molding as in Example 1 were performed, and Na containing bismuth was used.
^{A +} type ZSM-5 catalyst was prepared. When analyzed with an X-ray microanalyzer (EPMA), gallium was 0.6
wt%. 3 g of catalyst in the same reactor as in Example 1
And benzene / ethane = 10 /
Introduced at a rate of 1 at an ethane space velocity of 1.0 h ^-1 and reacted for 1 hour. One hour later, the selectivity and the reaction rate were styrene selectivity = 15%, ethylbenzene selectivity = 65%, and ethane reaction rate = 3%.

(Comparative Example 1) H ⁺ type Z prepared in Example 1
SM-5 was molded as a catalyst in the same manner as in Example 1, and reacted in the same manner as in Example 1. After one hour, the selectivity and the reaction rate are shown in Table 2.

(Comparative Example 2) The Na ⁺ type ZSM-5 prepared in Example 2 was molded as a catalyst in the same manner as in Example 1,
The reaction was performed in the same manner as in Example 1. After 1 hour selectivity,
The conversion is shown in Table 2.

Comparative Example 3 H ⁺ type Z prepared in Example 1
0.15 g of gallium nitrate and 10 g of water are added to 10 g of SM-5.
Was added, and the mixture was stirred sufficiently, the water was evaporated, and the resultant was further dried at 120 ° C. to impregnate the zeolite with gallium. Gallium impregnated zeolite in air 600
Calcination was performed at 8 ° C. for 8 hours. When analyzed by fluorescent X-ray, it contained 0.4% of gallium. The catalyst was molded in the same manner as in Example 1 and reacted in the same manner as in Example 1. 1
The selectivity and the reaction rate after the time are shown in Table 2.

[0030]

[Table 2]

[0031]

The one-stage styrene production method according to the present invention can provide a much simpler production method than the conventional two-stage styrene production method, so that it is an economical and energy-saving process and has high industrial value. Further, since an ethane raw material can be used in place of the ethylene raw material, production not depending on ethylene production becomes possible, and conversion to an environmentally compatible alkane raw material becomes possible.

Claims (3)

[Claims] 1. Ga, Ge, As, In, Sn, Sb,
A direct method for producing styrene, comprising contacting benzene with ethylene and / or ethane in the presence of a zeolite catalyst ion-exchanged with at least one metal element selected from Tl, Pb, and Bi. 2. The method for directly producing styrene according to claim 1, wherein the ion exchange is performed using a zeolite having an alkali metal cation. 3. The method according to claim 1, wherein the zeolite has a ZS having an MFI structure.
The method for producing styrene directly according to claim 1 or 2, wherein the styrene is M zeolite.