KR20190049209A - production of selective ethylene from propylene by acid treated ZSM-5 - Google Patents

Abstract

The present invention provides a method for manufacturing selective ethylene from propylene. More specifically, the present invention provides the method for manufacturing ethylene from propylene with high selectivity by using a ZSM-5 catalyst, which is treated with an acid, thereby having a controlled Bronsted acidity and Lewis acidity, and a controlled process.

Description

[0001] The present invention relates to a process for the production of selective ethylene from propylene by acid-treated ZSM-5,

The present invention relates to a process for selectively producing ethylene from propylene, and more particularly to a process for preparing ethylene with high selectivity from propylene under ZSM-5 catalysts treated with an acid and having a specific acidity.

Light olefins, ethylene and propylene, are the major bulk chemicals currently in the petrochemicals market and are an important basic raw material used in the manufacture of plastics as well as various chemicals such as synthetic rubber, packaging, textiles, building materials and furniture. Due to these various applications, the use of ethylene and propylene in the world market is expected to continue to increase in the future.

In particular, in the case of ethylene, more than 50% of ethylene is used in the production of polyethylene and ethylene copolymers in the world. In addition, there are various types of ethylene, hydrogenation, hydrogenation, alkylation, hydration, oligomerization, Chemical reactions are very important for the chemical industry and are supplied as various raw materials.

There are various routes for producing such light olefins in the petrochemical industry. However, there are various routes for producing such light olefins. However, steam produced by pyrolyzing hydrocarbon raw materials such as gas raw materials (ethane, propane) and liquid raw materials (naphtha, gas oil) Cracking process is the most common process. The yield of the product obtained through this steam cracking is mostly determined by the hydrocarbon feedstock used, and in the case of an ethane cracker using gaseous ethane as a raw material, mainly ethylene (about 83% yield) and a little fuel oil Is obtained as a by-product.

However, in the case of naphtha crackers, which account for the largest number of crackers currently operating for olefin production, C4 olefins, BTX aromatic oils and other fuels can be obtained as light olefins, ethylene and propylene by-products, , And a yield of about 16% of propylene.

The amount of ethylene produced in the petroleum-derived naphtha cracking process, which is the most commonly used process for producing olefins, is about two times higher than the amount of propylene produced. However, not only is the type of hydrocarbon feedstock used and the process applied, Because of the different types of industries producing light products using light olefins, the price gap between ethylene and propylene will inevitably vary depending on local demand and supply, such as the US, Europe, China, and Asia.

Therefore, there is a need to develop olefin interconversion techniques to balance the local supply and demand of light olefins between ethylene and propylene.

Ethylene-to-propylene (ETP) processes have been extensively studied from ethylene due to the expectation that propylene prices and demand will be relatively high in comparison with ethylene in general in the olefin interconversion studies.

Recently, however, many ethane crackers have been supplied by many newly built ethane crackers to use shale gas as a gas raw material in the United States. In Asia, however, not only are there a high demand for ethylene, but also a wide variety, such as naphtha crackers, PDH and MTP Because propylene feedstocks exist, propylene prices are relatively inexpensive relative to ethylene prices.

Therefore, it is necessary to develop propylene-to-ethylene (PTE) process that selectively converts propylene to ethylene in Asia.

 As a technology related to PTE, triolefin process using olefin metathesis reaction was developed and commercialized in the 1960s. This metathesis reaction employs a heterogeneous catalyst in which tungsten oxide is supported on a silica carrier, and two moles of propylene are theoretically converted into one ethylene and two-butene, respectively.

However, in the self-metathesis reaction of propylene itself, the one-pass selectivity is less than 35.3% and the selectivity of ethylene is not high. In order to maximize the ethylene yield in the process using the metathesis reaction The propylene as the raw material and the metathesis reactors of butene, the main by-product, and the reactor for decomposing the various hydrocarbons produced, must be constituted in series. Commercialization of ethylene production selectively from propylene through a metathesis path has been discontinued for reasons such as the above.

 On the other hand, zeolites have been used as solid acid catalysts in many catalytic processes in the chemical industry due to their unique shape selectivity and controllable acid sites. In particular, these features have led to high efficiencies in oil refineries and petrochemical processes. For example, zeolite catalysts exhibit high catalytic activity and production selectivity in a series of catalytic reactions such as cracking, isomerization, aromatization, disproportionation, alkylation. Most of the zeolites as catalysts in ethylene production have been used in additional processes of the overall process to improve the yield of light olefins and ethylene is obtained through catalytic cracking of olefins and hydrocarbons as reaction intermediates. The selectivity of ethylene in this catalytic cracking was reported to be as low as 12 ~ 30%.

Therefore, the application of existing technologies and catalysts is limited in order to produce ethylene selectively from propylene, and a new process for improving it is required.

International Patent Publication No. WO2005-014169

The present invention provides a process for the selective preparation of ethylene from propylene, which comprises a process for the production of ethylene using the metathesis reaction of propylene and the production of ethylene as a by-product in the cracking reaction of olefins and hydrocarbons, To produce ethylene with high selectivity from propylene in the presence of an acidity controlled ZSM-5 catalyst.

In order to achieve the above object, the present invention provides a process for selectively producing ethylene from propylene in the presence of a ZSM-5 catalyst, which is a specific catalyst having acidity controlled by treatment with an acid, A method for producing the above-

Acid to produce ethylene by reacting propylene under a ZSM-5 catalyst having a weak acidity of 0.09 mmol / g-catalyst or less and a strong acidity of 0.45 mmol / g-catalyst or less do.

Preferably, the acid according to one embodiment of the present invention may be one or more selected from hydrochloric acid, ammonium hexafluorosilicate, oxalic acid and ammonium fluoride.

Preferably, the ZSM-5 catalyst according to one embodiment of the present invention may have a Si / Al ₂ molar ratio of 30 to 80 or less, and may be treated with 0.005 to 0.5 mol of an acid.

Preferably, the weak acidity according to one embodiment of the present invention is 0.029 to 0.084 mmol / g catalyst and the acidity of acidity is 0.18 to 0.45 mmol / g catalyst.

Preferably, the ZSM-5 catalyst according to an embodiment of the present invention may have a strong acidity / weak acidity of 4.0 to 8.0 in view of high conversion and ethylene selectivity.

Preferably, the reaction according to one embodiment of the present invention is carried out at a temperature of 550 to 600 占 폚, atmospheric pressure of 1 to 10 KPa, hourly weight hourly space velocity of propylene of 0.1 to 10 hours ^-1 and propylene and nitrogen of 1: Dilution ratio.

Preferably, the ZSM-5 catalyst according to an embodiment of the present invention may be H-ZSM-5, and ZSM-5 may be one selected from the group consisting of La, Zn, Ni, Fe, Ga, Cu, Pd, Al, Co, Cr, Au, Pt, Re, Ru, and Ir.

The process for producing the selective ethylene from the propylene of the present invention can be carried out in a fixed bed reactor or a fluidized bed reactor, and preferably the conversion of propylene is 70% or more and the selectivity of ethylene is 60% or more.

The process for selectively producing ethylene from propylene of the present invention is very high in propylene conversion and ethylene selectivity using ZSM-5 catalysts treated with acid and controlled in acidity.

Further, the process for producing ethylene from propylene of the present invention significantly improves the selectivity of ethylene to be produced by reacting propylene under specific controlled reaction conditions with ZSM-5 having a specific range of acidity and a controlled range.

Thus, the recent low oil prices in the Asia-Pacific region have led to high production rates of naphtha crackers, resulting in massive production of propylene for demand, and PDH and petroleum substitution, an on-purpose process for the production of propylene from cheap natural gas (mostly propane) Or a non-petroleum raw material, methanol is used to produce an excess of propylene compared to local demand, since the MTP process is newly constructed and operated. Therefore, the process for producing the selective ethylene from the propylene of the present invention is characterized in that a high- It is possible to economically solve the imbalance in demand-supply of ethylene-propylene.

1 is a diagram showing the weak acidity, the strong acidity and the total acidity of each catalyst prepared in Example 4 of the present invention,
2 is a graph showing propylene conversion and ethylene selectivity in Example 5 and Comparative Example 1 of the present invention.
3 is a graph showing the yield of ethylene in Example 5 and Comparative Example 1 of the present invention.
4 is a graph showing the selectivity of ethylene according to the Si / Al ₂ molar ratio in Example 6 of the present invention.
5 is a graph showing the propylene conversion and ethylene selectivity of Example 7 of the present invention.
6 is a graph showing the conversion of propylene and the selectivity of ethylene according to the partial pressure of Example 8 of the present invention,
Figure 7 is a graph showing the effect of the acid treated ZSM-5 prepared in Examples 1 to 4 of the present invention Propylene conversion and ethylene selectivity. Fig.

The present invention provides a method for producing ethylene with high selectivity from propylene in the presence of ZSM-5 having acidity controlled by treatment with an acid,

Acid to produce ethylene by reacting propylene under a ZSM-5 catalyst having a weak acidity of 0.09 mmol / g-catalyst and a strong acidity of 0.45 mmol / g-catalyst or less.

The process for producing the selective ethylene from propylene of the present invention is a catalyst of a process for selectively producing ethylene from propylene, using a ZSM-5 catalyst controlled to have an acidity in a specific range by treatment with acid, Can be produced by reacting a ZSM-5 catalyst having a ZSM-5 catalyst with propylene at a high conversion and selectivity, and it is possible to obtain ethylene with high selectivity from propylene, rather than the production of olefins obtained from various by- Method.

Further, the process for producing selective ethylene from propylene according to the present invention is characterized in that the ZSM-5 catalyst is treated with a specific acid to selectively deal with the weak acid point by dealumination of the ZSM-5 catalyst to increase the conversion of propylene, Can be improved.

In other words, zeolite, including ZSM-5 catalyst, has strong and strong electron-dense and low-density portions, but as the Si / Al ₂ molar ratio is low, It is difficult to form strong acid sites, and the acidity is weak.

That is, when the density of the bridged Si-O-Al is high, the acidity of the zeolite is increased, while when the density of the isolated Si-O-Al is increased, the acidity is selectively decreased.

The inventors of the present invention have found that ethylene can be prepared from propylene with high conversion and selectivity as the ZSM-5 catalyst is treated with an acid to deal with the density of isolated Si-O-Al, And completed the invention.

That is, in the method of producing ethylene from propylene of the present invention, ethylene can be produced with high yield and selectivity by selectively controlling the acidity and strong acidity by treating the ZSM-5 catalyst with an acid.

The process for producing the selective ethylene from the propylene of the present invention is remarkably economical because it can obtain ethylene with remarkably improved selectivity and simple process unlike the conventional process and is surprising in comparison with the process for producing propylene from ethylene, And the method of selectively producing ethylene from propylene of the present invention can solve the supply imbalance of ethylene and propylene.

Preferably, the acid according to an embodiment of the present invention may be any one or two or more selected from ammonium hexafluorosilicate, hydrochloric acid, oxalic acid and ammonium fluoride and has a well-controlled acidity and is more preferable in terms of increasing the selectivity of ethylene May be ammonium hexafluorosilicate.

Specific catalysts used in the preparation of propylene from the propylene of the present invention are ZSM-5, which is different from zeolite catalysts ZSM-11, ZSM-22, HY, SSZ-13, SAPO-34, SAPO-11, mordenite and beta The conversion of propylene and the selectivity of ethylene are remarkably improved, and furthermore, the acidity is controlled by treating with an acid, especially ammonium hexafluorosilicate, to further improve conversion and selectivity.

The Bronsted acidity and Lewis acidity of the present invention are values measured by pyridine adsorption experiments (50 to 150 DEG C).

The strong acidity and weak acidity of the present invention are values measured by ammonia adsorption experiments (25 to 900 DEG C).

Preferably, the Si / Al ₂ molar ratio of ZSM-5 can be 23 to 80 or less, more preferably 30 to 80, even more preferably 30 to less than 80.

The ZSM-5 catalyst according to one embodiment of the present invention is treated with an acid, especially ammonium hexafluorosilicate, to control the acidity.

Preferably, the adjustment of the appropriate acid sites by the bridged Si-O-Al in the ZSM-5 catalyst reduces the formation of by-products through excessive hydrocarbon cracking or oligomerization and aromatization of the olefins, and ZSM- And the ZSM-5 acid sites generated by the neighboring aluminum in the ZSM-5 are appropriately maintained to inhibit the catalyst activity from being lowered. The Si / Al ₂ molar ratio of ZSM-5 may be from 23 to 100, preferably from 30 to 80, more preferably from 30 to 80, in view of increasing propylene conversion and ethylene selectivity, And more preferably from 50 to 80. [

Preferably, the ZSM-5 catalyst of the present invention may be treated with from 0.005 mol to 0.5 mol of the acid and treated with 0.05 mol to 0.25 mol of ammonium hexafluorosilicate in order to have an excellent propylene conversion and ethylene selectivity .

Preferably, the ZSM-5 catalyst in the process for preparing selective ethylene according to an embodiment of the present invention has a weak acidity according to an embodiment of the present invention is 0.025 to 0.085 mmol / g catalyst, preferably 0.025 to 0.085 mmol / g catalyst And a strong acidity of 0.18 to 0.45 mmol / g, more preferably a weak acidity of 0.03 to 0.07 mmol / g of catalyst, and a strong acidity of 0.20 to 0.41 mmol / g of catalyst.

Preferably, the ZSM-5 catalyst according to one embodiment of the present invention may have a ratio of strong acidity / weak acidity, that is, a ratio of weak acidity to weak acidity of 4.0 to 8.0.

Further, the Bronsted acidity of the present invention may be not more than 1.5 mmol / g-catalyst, the Lewis acidity is not more than 0.010 mmol / g-catalyst, the total acidity may be in the range of 0.22 to 0.55 mmol / g-catalyst, preferably the Bronsted acidity Catalyst may be 0.10 to 0.16 mmol / g-catalyst or less and a Lewis acidity of 0.05 to 0.008 mmol / g-catalyst or less and a total acidity of 0.25 to 0.48 mmol / g-catalyst.

The process for preparing the selective ethylene from propylene of the present invention can proceed with controlled reaction conditions as well as controlled acidity in order to improve the selectivity of ethylene.

1 to 1:30. This controlled reaction for the production of ethylene from propylene optionally in the invention is 550 to 600 ℃ temperature, of from 1 to 10KPa pressure, 0.1 to 10 hr ^-1, the propylene weight hourly space velocity of 1 and Propylene and nitrogen dilution ratio (volume ratio).

The preparation process according to an embodiment of the present invention simultaneously satisfies ZSM-5, a specific catalyst having an acidity of such a controlled specific range, and a specific range of reaction conditions, thereby greatly improving the propylene conversion and ethylene selectivity.

Preferably, the ZSM-5 catalyst according to an embodiment of the present invention may be H-ZSM-5, and ZSM-5 may be one selected from the group consisting of La, Zn, Ni, Fe, Ga, Cu, Pd, Al, Co, Cr, Au, Pt, Re, Ru, and Ir.

The process for producing the selective ethylene from propylene of the present invention can be carried out in a fixed-bed reactor or a fluidized bed reactor, and preferably the conversion of propylene is 60% or more, the selectivity of ethylene is 50% or more, The conversion rate is 70% or more, and the selectivity of ethylene may be 60% or more.

Specifically, in the process for producing the selective ethylene from the propylene of the present invention, the conversion of propylene into ethylene is limited to a specific value or higher and is a value obtained by the formula, and these formulas are described in the following examples.

In the method of selectively decomposing propylene, the zeolite has stronger and stronger acidity as a result of the formation of the electron-dense portion and the lower portion of the ZSM-5 catalyst. However, the lower the Si / Al ₂ molar ratio, the higher the electron density and the lower electron density The acidity of the acid is high because it is difficult to form a strong acid point.

That is, when the density of the bridged Si-O-Al is high, the acidity of the zeolite is increased, while when the density of the isolated Si-O-Al is increased, the acidity is selectively decreased.

The inventors of the present invention have found that ethylene can be prepared from propylene with high conversion and selectivity as the ZSM-5 catalyst is treated with an acid to deal with the density of isolated Si-O-Al, And completed the invention.

That is, in the case of the ZSM-5 catalyst treated with an acid, preferably ammonium hexafluorosilicate, the dealumination within the structure of the catalyst becomes an appropriate acid point, thereby increasing the conversion of propylene and increasing the selectivity of ethylene do.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

≪ Measurement of Bronsted acidity and Lewis acidity of catalyst >

The pyridine adsorption experiment was performed in a high-temperature chamber with a diffuse reflectance equipped with a window (Spectra-Tech). The chamber may be connected to a gas system to allow gas to flow through the chamber and to leave the chamber free of gas.

The sample was pulverized into fine powder and made into pellets and placed in a chamber for measurement. The sample was first heated to 250 DEG C and held at 250 DEG C for at least 1 hour while passing inert gas through the chamber. After cooling to 50 < 0 > C, the pyridine inert gas mixture was passed through the chamber for about 5 minutes. Thereafter, the flow of the pyridine was stopped, while the flow of the inert gas was continued, and the amount of pyridine passed through the chamber for 5 minutes was measured. After that, the flow of inert gas was heated to 150 DEG C over about 12 hours, , And the amount of chemically desorbed pyridine was measured. The pyridine absorbed at 50 占 폚 by the amount of pyridine absorbed in the Bronsted acid and Lewis acid sites was measured by using the pyrimidinium-band and the pyridine-Lewis acid band corresponding to the known extinction coefficient, Using the difference.

<Strong acidity, weak acidity and total acidity of catalyst>

The analytical techniques used to measure the strong acidity and weak acidity of the catalyst were measured from the acid intensity distribution chart by NH3-TPD (temperature-programmed desorption) and ammonia desorption desorption.

First, a sample was prepared as in the above-mentioned Bronsted acidity and Lewis acidity measurement, and the sample was pre-treated by heating at 500 ° C. for 60 minutes. After ammonia adsorption for 30 minutes at 100 ° C., / min and ammonia desorbed was measured using a TCD detector (thermal conductivity detector). The amount of the acid sites of the zeolite catalyst was determined by deconvolution of the measured TPD curves, and the amounts of weak acid sites and strong acid sites were calculated. The total acidity was the sum of the two acid sites.

&Lt; Calculation of Propylene Conversion Rate and Ethylene Selectivity >

The conversion of propylene and the selectivity of ethylene were calculated from the following formulas.

Cov. _{C3 =} denote conversion of C _{= 3;} M _{C3 =} to represents the mol of DMF at the initial time; MC _{3 =} is the mol of C _{3 =} at the desired reaction time; Selec. C _{2 =} denote the selectivity of product C _{2 =} ; M _{C2 =} is the mol of product C _{2 =} ; Yield C2 is yield of product C2 ₌ .

Example 1 Preparation of ZSM-5 Catalyst Treated with 0.1 M Oxalic Acid

1 g of ZSM-5 zeolite (Zeolyst, Si / Al ₂ = 50, CBV 5524G) was added to 20 ml of 0.1M oxalic acid, and the mixture was heated and refluxed at room temperature for 1 hour. After drying for 6 hours using dry oven, the prepared sample was heated at 60 ° C. for 5 hours at 550 ° C. to prepare a ZSM-5 catalyst treated with 0.1 M oxalic acid.

Example 2 Preparation of ZSM-5 Catalyst Treated with 0.1 M Ammonium Fluoride

A ZSM-5 catalyst treated with 0.1M ammonium fluoride was prepared in the same manner as in Example 1, except that ammonium fluoride was used instead of oxalic acid in Example 1 and the mixture was stirred for 72 hours at a final temperature of 500 ° C for 10 hours.

Example 3: Preparation of ZSM-5 catalyst treated with 0.1 M hydrochloric acid

In Example 1, hydrochloric acid instead of oxalic acid was used to conduct a heating and reflux reaction at 85 ° C for 4 hours, followed by washing with distilled water and firing at 400 ° C for 6 hours. The procedure of Example 1 was repeated to prepare a ZSM- 5 catalyst.

Example 4: Preparation of ZSM-5 catalyst treated with ammonium hexafluorosilicate

1 g of ZSM-5 zeolite (Zeolyst, Si / Al ₂ = 50, CBV 5524G) was added to 25 ml of 0.1M ammonium hexafluorosilicate, and the mixture was reacted at 90 ° C for 3 hours under reflux. Thereafter, the reaction mixture was dried in a dry oven for 6 hours, and the prepared sample was calcined at 500 ° C. for 5 hours to prepare a ZSM-5 catalyst treated with ammonium hexafluorosilicate 0.1 M, and used in this experiment .

ZSM-5 catalysts treated with ammonium hexafluorosilicate in an amount of 0.005, 0.05, 0.25 and 0.5 M were prepared, respectively, by changing the moles of ammonium hexafluorosilicate.

Each of the prepared catalysts had weak acidity, strong acidity and total acidity as shown in FIG. 1, and Bronsted acidity, Lewis acidity and total acidity were measured and the results are shown in Table 1 below.

Ammonium hexafluorosilicate concentration Weak acidity Strong acidity Strong acidity / weak acidity Bornstedt Lewis acid Total acidity 0.005 0.084 0.450 5.35 0.204 0.006 0.534 0.05 0.069 0.406 5.88 0.151 0.005 0.475 0.1 0.049 0.385 7.86 0.142 0.007 0.434 0.25 0.042 0.201 4.79 0.102 0.007 0.243 0.5 0.029 0.183 6.31 - - 0.212 Untreated 0.140 0.450 3.21 - - 0.590

[Example 5 and Comparative Example 1] Production of ethylene from propylene under ZSM-5 catalyst according to the treatment concentration of ammonium hexafluorosilicate

0.5 g of the ZSM-5 catalyst prepared in Example 4 of the present invention and 0.5 g of the ZSM-5 catalyst not treated with ammonium hexafluorosilicate were filled in a 0.5-inch fixed bed reactor, propylene was injected into the fixed bed reactor, Ethylene was prepared by carrying out the reaction at a reaction temperature of 550 ° C, 0.1 MPa and a WHSV of 1.09 h ^-1 , a partial pressure of propylene of 0.0065 MPa, and a total flow rate (propylene + nitrogen) of 70.6 ml / min , Propylene conversion and ethylene selectivity are shown in FIG. 2, and the yield of ethylene is shown in FIG.

As can be seen in Figures 2 and 3, the ZSM-5 catalyst of the present invention is superior to Comparative Example 1 (which is the leftmost bar graph of Figure 2) in which ammonium hexafluorosilicate is not treated, And that the yield of ethylene is high at the same time.

[Example 6] Production of ethylene from propylene according to Si / Al ₂ molar ratio

Except that ZSM-5 catalysts different in Si / Al ₂ molar ratio as described in Table 2 below were used as ZSM-5 catalysts treated with 0.1 M ammonium hexafluorosilicate (AHFS), respectively, in Example 5 The results are shown in Table 2 and FIG. 4.

Conversion CH4 C2H6 C2H4 C3H8 C5 + Total C4 = H-ZSM- (23) / AHFS 01M 86.79 22.25 3.10 37.12 6.96 27.87 1.70 78.13 15.49 5.32 44.29 10.73 18.39 5.25 H-ZSM- (50) / AHFS 01M 77.80 16.02 2.90 43.37 8.74 23.70 3.89 70.50 6.58 1.72 62.45 7.92 10.14 10.07 H-ZSM- (80) / AHFS 01M 54.04 5.59 1.70 58.18 6.23 10.50 10.38 62.70 5.29 2.31 62.44 8.65 8.83 10.72 H-ZSM- (280) / AHFS 01M 14.61 6.47 0.00 59.52 2.82 5.24 16.12 15.31 6.64 0.00 58.61 2.36 4.52 27.88

As shown in Table 2 and FIG. 4, the selectivity and the yield of ethylene are remarkably different depending on Si / Al ₂ molar ratio.

[Example 7] Production of ethylene from propylene under ZSM-5 catalyst treated with AHFS according to temperature

Ethylene was prepared from propylene using ZSM-5 treated with AHFS in the same manner as in Example 5 except that the temperature was changed to 400 ° C., 450 ° C., 500 ° C., 550 ° C., 600 ° C. and 650 ° C., respectively, The results are shown in Fig.

As shown in FIG. 5, it can be seen that the propylene conversion and ethylene selectivity differ depending on the temperature, and it can be seen that the selectivity and the yield are both excellent at 550 ° C.

[Example 8] Production of ethylene from propylene under ZSM-5 catalyst treated with AHFS according to partial pressure

Ethylene was prepared from propylene in the same manner as in Example 5, except that the partial pressure was changed in Example 5 as shown in Fig. 5. The results are shown in Fig.

As shown in FIG. 6, it can be seen that the conversion of propylene and the selectivity of ethylene are significantly different depending on the dilution ratio of propylene and nitrogen. The dilution ratio of propylene and nitrogen is 1: 1 to 1: 30, The selectivity can be seen.

Specifically, when the injection amount of propylene is fixed at 4.6 ml / min, the nitrogen input amount is in the range of 10 to 150 ml / min, that is, the dilution ratio of propylene and nitrogen is 1: 1 to 32, preferably 1: : 4 to 16.5 shows better conversion and selectivity.

[Example 9] Production of ethylene from propylene under ZSM-5 catalyst treated with hydrochloric acid, oxalic acid and ammonium fluoride, respectively

Ethylene was prepared from propylene in the same manner as in Example 5 except that the ZSM-5 catalyst prepared in each of Examples 1 to 3 was used in place of ammonium hexafluorosilicate in Example 5, Respectively.

As shown in FIG. 7, it can be seen that ethylene can be selectively prepared from propylene under an acid-treated ZSM-5 catalyst treated with an acid. Further, among various acids, ZSM-5 treated with ammonium hexafluorosilicate Ethylene can be produced with the highest selectivity and yield under the catalyst.

Claims (11)

Acid catalyst to produce ethylene by reacting propylene under a ZSM-5 catalyst having an acidity of 0.09 mmol / g-catalyst or less and a strong acidity of 0.45 mmol / g-catalyst or less. The method according to claim 1,
Wherein the acid is selected from propylene, one or two phases selected from hydrochloric acid, ammonium hexafluorosilicate, oxalic acid and ammonium fluoride. The method according to claim 1,
Wherein the ZSM-5 catalyst is selected from propylene having a Si / Al ₂ molar ratio of 30 to 80. The method according to claim 1,
Wherein said ZSM-5 catalyst is treated with 0.005 to 0.5 moles of an acid. The method according to claim 1,
Wherein the weak acidity is from 0.029 to 0.084 mmol / g of catalyst and the acidity of acidity is from 0.18 to 0.45 mmol / g of catalyst. The method according to claim 1,
Wherein said ZSM-5 catalyst is selected from propylene having a strong acidity / weak acidity degree of 4.0 to 8.0. The method according to claim 1,
Wherein the reaction is carried out at a temperature of from 550 to 600 占 폚, atmospheric pressure of from 1 to 15 KPa, a weight hourly space velocity of propylene of from 0.1 to 10 hours ^-1 and propylene and nitrogen dilution ratios of from 1: 1 to 1:35, &Lt; / RTI &gt; The method according to claim 1,
Wherein said ZSM-5 catalyst is H-ZSM-5. The method according to claim 1,
The ZSM-5 is characterized in that one or two or more selected from among La, Zn, Ni, Fe, Ga, Cu, Pd, Al, Co, M, Ce, Cr, Au, Pt, Re, &Lt; / RTI &gt; by weight of propylene. The method according to claim 1,
Wherein said step is carried out in a fixed bed reactor or a fluidized bed reactor. The method according to claim 1,
The production process is characterized in that the conversion of propylene is 70% or more, and the selectivity of ethylene is 60% or more.

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