KR20080114799A - Process for production of propylene - Google Patents

Abstract

A process for producing propylene efficiently from a raw material mixture comprising an olefin having four or more carbon atoms and at least one of methanol and dimethyl ether with high selectivity and in a high yield by inhibiting the production of by-products such as aromatic compounds or paraffins while keeping the reaction rate at a high level. The process comprises diluting a raw material mixture comprising an olefin having four or more carbon atoms and at least one of methanol and dimethyl ether with a diluent (C) (which consists of one or more members selected from among paraffins, aromatic compounds, steam, carbon dioxide, carbon monoxide, nitrogen, argon, and helium)in such a way as to satisfy the requirement (A) that the ratio of the amount by mole of the olefin fed into the reactor to the sum of the amount by mole of methanol fed into the reactor and twice the amount by mole of dimethyl ether fed thereinto is 0.5 to 10 and the requirement (B) that the total concentration of the olefin, methanol and dimethyl ether in the whole component fed into the reactor is 20 to 80% by volume, and subjecting the obtained dilution to catalytic reaction. ® KIPO & WIPO 2009

Description

Process for producing propylene {PROCESS FOR PRODUCTION OF PROPYLENE}

The present invention relates to a process for producing propylene from a raw material mixture containing olefins having 4 or more carbon atoms and at least one of methanol and dimethyl ether.

As a method for producing propylene, conventionally, steam cracking of naphtha and fluid catalytic cracking of reduced pressure diesel gas have been generally performed, and recently, at least one of a metathesis reaction based on ethylene and 2-butene or methanol and dimethyl ether is used. MTO processes based on dogs are also attracting attention. On the other hand, the method of manufacturing a lower olefin using a C4 or more olefin and oxygen compounds, such as methanol, as a raw material is also known (patent document 1).

In the said patent document 1, although the reaction is implemented on the conditions containing the high concentration of olefin and methanol in the Example, the reason is not clear. It is because there is no document specifically described in this way as far as this inventor knows.

However, in the present inventors' guess, the contact cracking of the C4 or more olefin which does not add oxygen-containing compounds, such as methanol, thinks that it was what the inventor of patent document 1 thought if it is generally performed on the conditions of high concentration olefin. do.

Thus, confirmation experiments as described in Reference Examples 1 and 2 described later were conducted. As a result, as the olefin concentration of the raw material is lower, by-products such as aromatic compounds and paraffins are suppressed. However, it was confirmed that a problem occurs that the reaction rate is slowed to increase the required amount of catalyst. For this reason, it was estimated that in Patent Document 1, the reaction was performed under the conditions containing high concentration of olefin and methanol to avoid such a problem.

Patent Document 1: US Patent No. 6888038

Disclosure of the Invention

Problems to be Solved by the Invention

However, in producing propylene from a raw material mixture containing olefins having 4 or more carbon atoms and at least one of methanol and dimethyl ether, employing high concentration reaction conditions leads to an increase in the amount of by-products such as aromatic compounds and paraffins. The formation of these undesirable by-products not only lowers the yield of the desired propylene, but also adversely affects the reaction process, such as promoting catalyst deterioration and troublesome purification process.

In the present invention, in the production of propylene by contacting a raw material mixture containing olefins having 4 or more carbon atoms and at least one of methanol and dimethyl ether with a catalyst in a reactor, the reaction rate is maintained to suppress byproducts such as aromatic compounds and paraffins. Another object is to provide a method for producing propylene at high selectivity and efficiently.

Means to solve the problem

MEANS TO SOLVE THE PROBLEM The present inventors earnestly examined in order to solve the said subject, fundamentally reviewing the conventional propylene manufacturing conditions at the time of using oxygen-containing compounds, such as methanol, and the common technical knowledge of the prior art, methanol, dimethyl In the reaction system containing an oxygen-containing compound such as ether in the raw material, even if the concentration of olefin, methanol and dimethyl ether in the raw material is lowered, the reaction rate decreases (that is, the conversion rate of the target butene) hardly occurs, and these By lowering the concentration, it is possible to remarkably suppress the formation of undesirable by-products such as aromatic compounds and paraffins, and to lengthen the catalyst life. As a result, propylene can be produced highly selectively and efficiently without increasing the amount of catalyst. It was found that the present invention was reached.

That is, the 1st summary of this invention makes the raw material mixture containing a C4 or more olefin and at least 1 of methanol and dimethyl ether so that the following conditions (A) and (B) satisfy | fill with the following diluent (C) And a step of contacting a raw material mixture containing dilution and at least one of dilute olefins having at least 4 carbon atoms and methanol and dimethyl ether with a catalyst in a reactor.

Condition (A): 0.5 or more and 10 or less by molar ratio with respect to the sum total of 2 or more times the number of moles of methanol and the number of moles of dimethyl ether supplied to the reactor with the amount of C4 or more olefins supplied to a reactor.

Condition (B): 20 volume% or more and 80 volume% or less of the total concentration of a C4 or more olefin, methanol, and a dimethyl ether in all the feed components supplied to a reactor

Condition (C): One or two or more selected from paraffins, aromatics, water vapor, carbon dioxide, carbon monoxide, nitrogen, argon and helium

A second aspect of the present invention is a method for producing propylene, in the above method, wherein the catalyst contains zeolite as a catalytically active component.

According to a third aspect of the present invention, in the above method, the zeolite is one or more mixtures selected from MFI, MEL, MOR, MWW, CHA, BEA, and FAU.

According to a fourth aspect of the present invention, in the above method, the zeolite is one or a plurality of mixtures selected from MFI, MEL, MWW and CHA.

In a fifth aspect of the present invention, there is provided a method for producing propylene, in which the gas temperature at the reactor inlet is 400 ° C or more and 600 ° C or less.

In a sixth aspect of the present invention, there is provided a method for producing propylene, in which the reactor is a fixed bed reactor.

In a seventh aspect of the present invention, there is provided a method for producing propylene, in which the at least part of the hydrocarbon having 4 or more carbon atoms contained in the reactor outlet gas is recycled to the reactor inlet.

Effects of the Invention

According to the present invention, in the production of propylene from a raw material mixture containing olefins having 4 or more carbon atoms and at least one of methanol and dimethyl ether, the reaction rate is maintained to suppress by-products such as aromatic compounds and paraffins, thereby providing high selectivity. Propylene can be efficiently produced in high yields.

Implement the invention  Best form for

EMBODIMENT OF THE INVENTION Although the typical aspect for implementing this invention below is demonstrated concretely, this invention is not limited to the following aspect, unless the summary is exceeded.

[catalyst]

First, the catalyst used by this invention is demonstrated.

The catalyst to be used in the reaction according to the present invention is not particularly limited as long as it is in the form of a solid having a Brentstead acid point. Conventionally known catalysts are used, for example, clay minerals such as kaolin; Impregnated and supported with acids such as sulfuric acid and phosphoric acid in a carrier such as clay mineral; Acidic ion exchange resins; Zeolites; Aluminum phosphates; And solid acid catalysts such as mesoporous silica alumina such as Al-MCM41.

Among these solid acid catalysts, those having a molecular sieve effect are preferable, and it is preferable that the acid strength is not too high.

As the structures of the zeolites and aluminum phosphates having the molecular sieve effect among the solid acid catalysts, represented by codes prescribed by the International Zeolite Association (IZA), for example, AEI, AET, AEL, AFI, AFO, AFS, AST , ATN, BEA, CAN, CHA, EMT, ERI, EUO, FAU, FER, LEV, LTL, MAZ, MEL, MFI, MOR, MTT, MTW, MWW, OFF, PAU, RHO, STT, TON have. Among these, catalysts having a framework density of 18.0 T / nm ³ or less are preferred, and such catalysts are preferably MFI, MEL, MOR, MWW, FAU, BEA, CHA, and more preferably MFI, MEL, MOR. , MWW, CHA, and particularly preferably MFI, MEL, MWW, CHA.

Here, the framework density (unit: T / nm ³ ) means the number of T atoms (atoms other than oxygen among the atoms constituting the skeleton of the zeolite) per unit volume (1 nm ³ ) of the zeolite, This value is determined by the structure of the zeolite.

More preferably, the solid acid catalyst has micropores having a pore diameter of 0.3 to 0.9 nm, a crystalline alumino having a BET specific surface area of 200 to 700 m 2 / g and a pore volume of 0.1 to 0.5 cc / g. Silicates, metalosilicates, metalloaluminosilicates or crystalline aluminum phosphates are preferred. In addition, the pore diameter here refers to the crystallographic free diameter of the channels defined by the International Zeolite Association (IZA), and is described in ATLAS OF ZEOLITE FRAMEWORKTYPES FIFTH RIVISED EDITION 2001 (ELSEVIER). When the shape of the pores (channels) is a round shape, the diameter thereof is indicated, and when the shape of the pores is elliptical, the short diameter is indicated.

During the addition, the aluminosilicate, preferably at least a molar ratio of _{SiO 2 / Al 2 O 3 10} . If the SiO ₂ / Al ₂ O ₃ molar ratio is too low, it is not preferable because the durability of the catalyst is lowered. The upper limit of the SiO ₂ / Al ₂ O ₃ molar ratio is usually 10000 or less, preferably 2000 or less. If the molar ratio of SiO ₂ / Al ₂ O ₃ is too high, it is not preferable because the catalytic activity is lowered. The molar ratio can be obtained by conventional methods such as fluorescence X-rays and chemical analysis.

The aluminum content in the catalyst can be controlled by the amount of raw material injected during preparation of the catalyst, and Al can be reduced by steaming or the like after preparation. In addition, a part of Al may be substituted with other elements, such as boron and gallium, and it is preferable to substitute with boron especially.

These catalysts may be used individually by 1 type, and may mix and use 2 or more types.

In the present invention, the catalytically active component as described above may be used as the catalyst as it is in the reaction, granulated and molded using a substance or a binder inert to the reaction, or a mixture thereof is used for the reaction. You may also do it. Examples of the substance or binder which are inert to the reaction include alumina or alumina sol, silica, silica gel, quartz, and mixtures thereof.

In addition, the said catalyst composition is a composition only of the catalytically active component which does not contain the substance, binder, etc. which are inert to these reactions. However, when the catalyst according to the present invention contains a substance, a binder, or the like which is inert to these reactions, the above-mentioned catalytically active component and a substance, a binder, and the like which are inert to the reaction thereof are referred to as a catalyst. When it does not contain the substance, binder, etc. which are inert to a reaction, only a catalyst active component is called a catalyst.

Although the particle diameter of the catalyst used by this invention differs according to the conditions at the time of synthesis, it is normally 0.01 micrometer-500 micrometers as an average particle diameter. If the particle size of the catalyst is too large, the surface area showing the catalytic activity is small, and if the particle size is too small, the handleability is poor, which is not preferable in either case. This average particle diameter can be calculated | required by SEM observation etc.

The preparation method of the catalyst used by this invention is not specifically limited, It can be prepared by the well-known method generally called hydrothermal synthesis. In addition, after hydrothermal synthesis, the composition may be changed by modifications such as ion exchange, dealumination treatment, impregnation, and supporting.

When used for the reaction, the catalyst used in the present invention may be one having the above physical properties or composition, and may be prepared by any method.

[Reaction raw material]

Next, the C4 or more olefin, methanol, and dimethyl ether which are used as a reaction raw material in this invention are demonstrated.

<Olefin>

It does not specifically limit as a C4 or more olefin used as a raw material of reaction. For example, those produced by catalytic cracking or steam cracking from a petroleum feedstock (C4 raffinate-1, C4 raffinate-2, etc.), FT (using a hydrogen / CO mixed gas obtained by gasification of coal as a raw material) Obtained by performing Fischer Tropsch) synthesis, obtained by oligomerization reaction including dimerization reaction of ethylene, obtained by dehydrogenation or oxidative dehydrogenation method of C4 or more paraffin, obtained by MTO reaction, Olefin having 4 or more carbon atoms, particularly 4 to 10 carbon atoms obtained by various known methods such as those obtained by dehydration of alcohols and those obtained by hydrogenation of diene compounds having 4 or more carbon atoms, may be optionally used. The thing of the state in which the compound other than a C4 or more olefin which originates in a manufacturing method was mixed arbitrarily as it is And also using, it may be used a purified olefin.

<Methanol, Dimethyl Ether>

The production origin of at least one of methanol and dimethyl ether used as a raw material for the reaction is not particularly limited. For example, those obtained by the hydrogenation reaction of coal / natural gas and a mixed gas of hydrogen / CO derived from by-products in the steelmaking industry, those obtained by the reforming reaction of alcohols derived from biomass, and obtained by the fermentation method The thing obtained from organic substances, such as a thing and recycled plastics or municipal waste, etc. are mentioned. Under the present circumstances, the thing of the state in which the compound other than methanol and dimethyl ether resulting from each manufacturing method was arbitrarily mixed may be used as it is, or the refined thing may be used.

[Reaction operation, condition]

The operation and conditions of the propylene production reaction of the present invention using the catalyst and the reaction raw material described above will be described below.

<Reactor>

The reaction of at least one of olefins having 4 or more carbon atoms and methanol and dimethyl ether in the present invention is a gas phase reaction. Although the form of this gas phase reactor is not specifically limited, Usually, a continuous fixed bed reactor or a fluidized bed reactor is selected.

In addition, when filling the reactor with the catalyst described above, in order to suppress the temperature distribution of the catalyst layer to be small, particulate matter inert to the reaction of quartz sand, alumina, silica, silica alumina, or the like may be mixed with the catalyst and filled. In this case, the usage-amount of the granular material inert to reaction of quartz sand etc. is not specifically limited. Moreover, it is preferable that this granular material is the particle size of the same grade as a catalyst from a uniform mixing property with a catalyst.

Moreover, you may divide and supply a reaction substrate (reactive raw material) for the purpose of disperse | distributing the exotherm accompanying a reaction.

The catalyst used in the present invention has less caulking and has a lower rate of catalyst deterioration than conventional catalysts, but it is necessary to perform catalyst regeneration during the operation when continuous operation is performed for one year or more.

For example, in the case of selecting a fixed bed reactor, it is preferable to install at least two reactors and operate while switching the reaction and regeneration. As the form of the fixed bed reactor, a multi-tubular reactor or adiabatic reactor is selected.

On the other hand, when selecting a fluidized bed reactor, it is preferable to send a catalyst continuously to a regeneration tank, and to perform reaction, returning the catalyst regenerated in a regeneration tank to a reactor continuously.

Here, as the regeneration operation of the catalyst, regeneration by treating the catalyst introduced from the reactor with nitrogen gas, water vapor or the like containing oxygen may be mentioned.

<Supply concentration ratio of at least one of olefin and methanol and dimethyl ether>

In the present invention, the amount of olefins having 4 or more carbon atoms to be supplied to the reactor is 0.5 or more, preferably 0.8 or more and 10 or less in molar ratio with respect to the total of twice the number of moles of methanol and the number of moles of dimethyl ether supplied to the reactor. , Preferably it is 5 or less (condition (A)).

That is, when the supply molar amount of olefins having 4 or more carbon atoms is M _c4 , the supply molar amount of methanol is M _m , and the supply molar amount of dimethyl ether is M _dm , M _c4 is 0.5 to 10 times of (M _m + 2M _dm ), preferably Preferably 0.8 to 5 times.

Even if this feed concentration ratio is too low or too high, reaction will become slow and it is unpreferable. Especially, when this feed concentration ratio is too low, since the consumption of olefin of a raw material reduces, it is unpreferable.

That is, in the present invention, by supplying olefins having 4 or more carbon atoms and at least one of methanol and dimethyl ether at a suitable concentration ratio, the substrate concentration to be described later is lowered to significantly increase the reaction rate.

In addition, when supplying a C4 or more olefin and at least 1 of methanol and dimethyl ether to a reactor, you may supply these, respectively, and may supply after mixing some or all previously.

<Substrate concentration>

In the present invention, the total concentration (substrate concentration) of olefins having 4 or more carbon atoms, methanol and dimethyl ether in the total feed components to be supplied to the reactor is 20% by volume or more and 80% by volume or less, preferably 30% by volume or more and 70% by volume. (Condition (B)) is as follows.

When the substrate concentration is too high, the production of aromatic compounds and paraffins becomes remarkable, and the selectivity of propylene tends to decrease. On the contrary, when the substrate concentration is too low, a large amount of catalyst is required because the reaction rate is slowed, and the cost of purification of the product and the construction cost of the reaction equipment are also large and not economical.

By carrying out the reaction within the above preferred substrate concentration range, it is possible to produce propylene at a low cost while suppressing the generation of undesirable by-products with an appropriate catalytic amount.

Therefore, in this invention, the reaction substrate is diluted with the diluent (diluent (C)) described below so that it may become such a substrate concentration.

<Diluent>

In the reactor, a gas inert to the reaction, such as paraffins, aromatics, water vapor, carbon dioxide, carbon monoxide, nitrogen, argon, helium, and mixtures thereof, in addition to olefins having 4 or more carbon atoms and at least one of methanol and dimethyl ether, Can exist. Moreover, among these diluents, although paraffins and aromatics may react slightly depending on reaction conditions, since reaction amount is small, it is defined as a diluent.

As such a diluent, the impurity contained in the reaction raw material may be used as it is, or the diluent prepared separately may be mixed with the reaction raw material and used.

In addition, the diluent may be mixed with the reaction raw materials before being put into the reactor, or may be supplied to the reactor separately from the reaction raw materials.

<Space velocity>

The space velocity herein refers to a flow rate of olefins having 4 or more carbon atoms which is a reaction raw material per weight of the catalyst (catalyst active component), and the weight of the catalyst is a catalyst that does not contain an inert component or binder used for assembling / forming the catalyst. The weight of the active ingredient. In addition, a flow volume is a flow volume (weight / hour) of an olefin of 4 or more carbon atoms.

The space velocity is between 500hr ^-1 preferably from 0.1hr ^-1, and more preferably between 1.0hr ^-1 at 100hr ^-1. If the space velocity is too high, the conversion ratio of at least one of the olefin of the raw material, methanol and dimethyl ether is low, and sufficient propylene selectivity cannot be obtained. In addition, if the space velocity is too low, the amount of catalyst required to obtain a constant yield increases, the reactor becomes too large, and undesirable by-products such as aromatic compounds and paraffins are generated, and thus the propylene selectivity is lowered, which is not preferable. .

<Reaction temperature>

The lower limit of the reaction temperature is usually about 300 ° C. or higher, preferably 400 ° C. or higher as the gas temperature at the reactor inlet, and the upper limit of the reaction temperature is usually 700 ° C. or lower, preferably 600 ° C. or lower. When reaction temperature is too low, reaction rate is low, there exists a tendency for many unreacted raw materials to remain, and the yield of propylene also falls. On the other hand, when reaction temperature is too high, the yield of propylene will fall remarkably.

<Reaction pressure>

The upper limit of the reaction pressure is usually 2 MPa (absolute pressure, the same below) or less, preferably 1 MPa or less, and more preferably 0.7 MPa or less. In addition, the minimum of reaction pressure is although it does not restrict | limit especially, Usually, it is 1 kPa or more, Preferably it is 50 kPa or more. If the reaction pressure is too high, the amount of undesired by-products such as paraffins and aromatic compounds increases, and the yield of propylene tends to decrease. If the reaction pressure is too low, the reaction rate tends to be slow.

<Reaction product>

As the reactor outlet gas (reactor effluent), a mixed gas containing propylene as the reaction product, unreacted raw materials, by-products and diluents is obtained. The propylene concentration in this mixed gas is 5 to 95 weight% normally.

The unreacted raw material is usually an olefin having 4 or more carbon atoms. Depending on the reaction conditions, at least one of methanol and dimethyl ether is contained, but the reaction is preferably performed under reaction conditions in which the conversion ratio of at least one of methanol and dimethyl ether is 100%. This facilitates separation of the reaction product and the unreacted raw material.

Examples of the by-product include ethylene, olefins having 4 or more carbon atoms, paraffins, aromatic compounds, and water.

<Separation of product>

The mixed gas containing propylene, unreacted raw materials, by-products, and diluents, which are reaction products as the reactor outlet gas, may be introduced into a known separation and purification facility, and may be recovered, purified, recycled, and discharged according to each component. .

One embodiment of this separation and purification method includes a step of cooling and compressing the gas at the reactor outlet and removing most of the condensed water, and removing the water to remove the hydrocarbon fluid containing some water. The method including the process of drying with benzene and then refine | purifying each olefin and paraffin by distillation is applied. In the above method, the compressed hydrocarbon fluid may be supplied to one distillation column, but a multistage compressor may be installed to separate crude hydrocarbons that are easily condensed and hydrocarbons that are difficult to condensate, and these may be supplied to the distillation column to carry out distillation. You may also do it.

It is preferable to recycle part or all of components other than propylene (olefin, paraffin, etc.) by mixing with a reaction raw material or supplying directly to a reactor after the said separation and purification. In addition, the components which are inert to the reaction in the by-product can be reused as a diluent.

Although an Example is given to the following and this invention is demonstrated to it further more concretely, this invention is not limited to a following example at all.

In addition, the catalyst used by the following example, the comparative example, and the reference example was prepared as follows.

[Catalyst preparation]

<Preparation Example 1>

26.6 g of tetrabromide-n-propylammonium (TPABr) and 4.8 g of sodium hydroxide were sequentially dissolved in 280 g of water, followed by colloidal silica (SiO _2). = 40 weight%, Al <0.1 weight%) The liquid mixture of 75g and 35g of water was added slowly, and it fully stirred, and obtained the aqueous gel. Next, this gel was poured into a 1000 ml autoclave, and hydrothermal synthesis was carried out at 170 ° C. for 72 hours while stirring at 300 rpm under self pressure. The product isolate | separated the solid component by pressure filtration, and after washing with water sufficiently, it dried at 100 degreeC for 24 hours. The catalyst after drying was baked at 550 degreeC for 6 hours under air circulation, and Na type aluminosilicate was obtained.

2.0 g of this Na type aluminosilicate was suspended in 40 cc of 1 M ammonium nitrate aqueous solution, and it stirred at 80 degreeC for 2 hours. The liquid after treatment separated the solid component by suction filtration, and after washing with water sufficiently, it was suspended in 40 cc of 1M ammonium nitrate aqueous solution again, and stirred at 80 degreeC for 2 hours. The liquid after treatment separated the solid component by suction filtration, and after washing with water sufficiently, it dried at 100 degreeC for 24 hours. The catalyst after drying was baked at 500 degreeC under air circulation for 4 hours, and H type aluminosilicate (called "catalyst A") was obtained.

This catalyst A confirmed that the structure of a zeolite was MFI type by XRD (X-ray diffraction).

The composition of this catalyst A was quantified by chemical analysis to find SiO ₂ / Al ₂ O ₃ = 1100 (molar ratio).

<Preparation Example 2>

26.6 g of tetrabromide-n-propylammonium (TPABr), 12.4 g of boric acid, 1.25 g of aluminum nitrate 9 hydrate, and 4.8 g of sodium hydroxide were sequentially dissolved in 280 g of water, followed by colloidal silica (SiO ₂ = 40 weight). %, Al = about 0.06 weight%) The liquid mixture of 75 g and 35 g of water was added slowly, and it fully stirred, and obtained the aqueous gel. Next, this gel was injected into a 1000 ml autoclave, and hydrothermal synthesis was performed at 170 ° C. for 72 hours while stirring at 300 rpm under self-pressure. Subsequent processes performed the same operation as Preparation Example 1 to obtain an H-type boroaluminosilicate (called "catalyst B").

This catalyst B confirmed that the structure of the zeolite was MFI type by XRD.

As a result of quantifying the composition of this catalyst B by chemical analysis, SiO ₂ / Al ₂ O ₃ = 324 (molar ratio) and SiO ₂ / B ₂ O ₃ = 94 (molar ratio).

[Production of propylene]

Below, the manufacture example and the comparative example of the propylene which used the said catalyst A, B are shown.

<Example 1>

Propylene was produced using Catalyst A.

In the reaction, a mixture of 25 mg of the catalyst A and 0.5 g of quartz was charged into a quartz reaction tube having an inner diameter of 6 mm using a atmospheric pressure fixed bed flow reactor. This reactor was supplied with a gas prepared from isobutene (20% by volume), methanol (10% by volume) and nitrogen (70% by volume) through an evaporator. Reaction temperature (reactor inlet gas temperature) was 550 degreeC. 70 minutes after the start of the reaction, the product was analyzed by gas chromatography.

Table 1 shows the reaction conditions and the reaction results.

The butene conversion was 51.2%, the methanol conversion was 100%, and the selectivity for propylene was 52.7%. On the other hand, the selectivity of the sum total of an aromatic compound and paraffin was 1.8%, and was very low level.

<Example 2>

The reaction was carried out under the same reaction conditions as in Example 1 except that the concentration of isobutene and methanol in the source gas concentration was doubled, respectively. Table 1 shows the reaction conditions and the reaction results. The butene conversion was 64.7%, the methanol conversion was 100%, and the selectivity for propylene was 54.9%. Although the selectivity of the sum total of an aromatic compound and paraffin was 6.4%, although it was higher than Example 1, it was a low level.

<Example 3>

The reaction was carried out under the same reaction conditions as in Example 1 except that the concentrations of isobutene and methanol in the source gas concentration were respectively 2.33 times. Table 1 shows the reaction conditions and the reaction results. The butene conversion was 64.9%, the methanol conversion was 100%, and the selectivity for propylene was 52.7%. Although the selectivity of the sum total of an aromatic compound and paraffin was 9.1%, it was higher than Example 1, 2, but was a low level.

Comparative Example 1

The reaction was carried out under the same reaction conditions as in Example 1 except that the concentration of isobutene and methanol in the source gas concentration was tripled. Table 1 shows the reaction conditions and the reaction results. The butene conversion was 65.1%, the methanol conversion was 100%, and the selectivity for propylene was 47.4%. The selectivity of the sum total of the aromatic compound and the paraffin was 15.3%, which was remarkably increased compared with Examples 1-3, and the selectivity of propylene was also not a level which can satisfy | fill.

<Example 4>

The reaction was carried out in the same manner as in Example 1 except that the catalyst B was used instead of the catalyst A, and a gas prepared with 15 vol% of isobutene, 15 vol% of methanol, and 70 vol% of nitrogen was supplied to the reactor through an evaporator. Table 1 shows the reaction conditions and the reaction results. The butene conversion was 50.0%, the methanol conversion was 100%, and the selectivity for propylene was 52.7%. On the other hand, the selectivity of the sum total of an aromatic compound and paraffin was 2.1%, and was very low level.

Example 5

The reaction was carried out under the same reaction conditions as in Example 4 except that the concentration of isobutene and methanol in the source gas concentration was doubled, respectively. Table 1 shows the reaction conditions and the reaction results. The butene conversion was 59.0%, the methanol conversion was 100%, and the selectivity for propylene was 54.7%. Although the selectivity of the sum total of an aromatic compound and paraffin was 5.7%, it was higher than Example 4, but was a low level.

<Example 6>

The reaction was carried out under the same reaction conditions as in Example 4 except that the concentrations of isobutene and methanol of the source gas concentration were respectively 2.33 times. Table 1 shows the reaction conditions and the reaction results. The butene conversion was 59.2%, the methanol conversion was 100%, and the selectivity for propylene was 52.1%. Although the selectivity of the sum total of an aromatic compound and paraffin was 8.4%, it was higher than Example 4, 5, but was a low level.

Comparative Example 2

The reaction was carried out under the same reaction conditions as in Example 4 except that the concentration of isobutene and methanol in the source gas concentration was tripled. Table 1 shows the reaction conditions and the reaction results. The butene conversion was 59.5%, the methanol conversion was 100%, and the selectivity for propylene was 47.6%. The selectivity of the sum of the aromatic compound and the paraffin was 14.8%, which was remarkably increased in comparison with Examples 4 to 6, and the selectivity of propylene was not a level that could be satisfied.

<Reference Examples 1,2>

The reaction was carried out under the same reaction conditions as in Examples 1 and 2, except that the supply flow rate of nitrogen was increased instead of methanol as the starting material. Table 1 shows the reaction conditions and the reaction results. In Examples 1 and 2, the conversion rate did not change significantly even when the raw material concentration was 1/2, whereas in Reference Examples 1 and 2, the conversion rate was greatly decreased by the raw material concentration being 1/2.

Although this invention was detailed also demonstrated with reference to the specific embodiment, it is clear for those skilled in the art that various changes and correction can be added without deviating from the mind and range of this invention.

This application is based on the JP Patent application (Japanese Patent Application 2006-112254) of an application on April 14, 2006, The content is taken in here as a reference.

The present invention, in the production of propylene by contacting a raw material mixture containing olefins having 4 or more carbon atoms and at least one of methanol and dimethyl ether with a catalyst in a reactor, maintains the reaction rate to suppress byproducts such as aromatic compounds and paraffins. This provides a method for producing propylene at high selectivity and efficiently.

Claims (7)

Diluting a raw material mixture containing at least one of olefins having 4 or more carbon atoms and methanol and dimethyl ether to satisfy the following conditions (A) and (B) with the following diluent (C); and diluting 4 or more carbon atoms. A process for producing propylene, comprising contacting a raw material mixture containing olefins and at least one of methanol and dimethyl ether with a catalyst in a reactor: Condition (A): 0.5 or more and 10 or less by molar ratio with respect to the sum total of 2 or more times the number of moles of methanol and the number of moles of dimethyl ether supplied to the reactor with the amount of C4 or more olefins supplied to a reactor, Condition (B): 20 volume% or more and 80 volume% or less of the total concentration of a C4 or more olefin, methanol, and a dimethyl ether in all the feed components supplied to a reactor, Condition (C): 1 type or 2 or more types chosen from paraffins, aromatics, water vapor, carbon dioxide, carbon monoxide, nitrogen, argon, and helium. The method of claim 1, And the catalyst contains zeolite as the catalytically active component. The method of claim 2, The zeolite is a method for producing propylene, characterized in that one or a plurality of mixtures selected from MFI, MEL, MOR, MWW, CHA, BEA and FAU. The method of claim 3, wherein The zeolite is a method for producing propylene, characterized in that one or a plurality of mixtures selected from MFI, MEL, MWW and CHA. The method according to any one of claims 1 to 4, The gas temperature at the reactor inlet is 400 ° C or more and 600 ° C or less. The method according to any one of claims 1 to 5, Process for producing propylene, characterized in that the reactor is a fixed bed reactor. The method according to any one of claims 1 to 6, At least a portion of the hydrocarbon having 4 or more carbon atoms contained in the reactor outlet gas is recycled to the reactor inlet.