JPH02225425A - Production of hydrocarbon containing magnesia as one component of catalyst - Google Patents

Abstract

PURPOSE:To obtain >=2C hydrocarbon by using a catalyst comprising highly purified and ultratinely pulverized single crystal magnesium oxide, alkali metal oxide and 3-4 valent metal oxide in bringing a methane-containing gas into contact with an oxygen-containing gas in the presence of catalyst. CONSTITUTION:An oxidative coupling reaction is performed by bringing a methane-containing gas and an oxygen-containing gas both heated at 500-1500 deg.C into contact with complex oxide catalyst to obtain >=2C hydrocarbon such as ethylene, ethane or propylene. The catalyst is composed of (A) highly purified and ultratinely pulverized single crystal magnesium oxide as a carrier, (B) alkali metal oxide and (C) oxide of trivalent metal (e.g. V, Cr, Mn or Fe) or tetravalent metal (e.g. Ti, Mn or Ge) able to be complex oxide of NaCl-type structure together with the components A and B. A small amount of said catalyst is used to afford the aimed substance in high conversion ratio and high selectivity coefficient at relatively low temperature.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is a method for producing hydrocarbons having a carbon number of 2 or more, such as ethylene, ethane, and propylene, by bringing a methane-containing gas and an oxygen-containing gas into contact with each other in the presence of a catalyst. The present invention relates to a method for manufacturing.

[Prior art] Olefinic hydrocarbons, especially lower olefinic hydrocarbons such as ethylene and propylene, have 2ffl bonds between carbons and are highly reactive, so they are currently one of the extremely important basic raw materials for petrochemical products. It is. Wet natural gas (mainly ethane and higher hydrocarbons) in the United States and Canada
Since it is available in abundance and at low cost, the manufacturing method that uses naphtha as a raw material is overwhelmingly used, but in Japan and Europe, the method that uses naphtha as a raw material and thermally decomposes it has been mainly adopted.

However, since the oil crisis in 1971, each country has tried to disperse and diversify their raw materials from naphtha or wet natural gas (side-side type), and one of the H-power candidates is dry natural gas (the main component of which is methane). ) is the raw material for producing ethylene.

Currently, the recoverable reserves of dry natural gas are comparable to those of oil, and new deposits have been discovered one after another recently, and the ultimate recoverable reserves are estimated to be 200 to 250 trillion m'. Furthermore, unlike oil resources, this natural gas is widely distributed around the world. Despite this, the utilization rate of this natural gas is still low worldwide.

Under these circumstances, each country is currently researching and developing ethylene production methods using dry natural gas as a raw material, and many legal texts and patents have been issued (1Δ) so far.

That is, in G, Keller et al. (J, or Cat
lysis739 (1982)) is the conversion reaction (
Oxidative coupling), manganese (Mn), cadmium (
It has been reported that alumina catalysts supporting oxides such as Cd) are promising, but their methane conversion rate (5% or less)
and the selectivity for ethylene and ethane (45% or less) is extremely low. Also, the temperature required for the reaction is relatively high (800°C). It.

et al. (J, ^a, chem, soc, 1075062 (1
985)) investigated the use of a lithium (Li)-magnesia (MgO)-based catalyst prepared by a conventional catalytic WE manufacturing method for the oxidative coupling of methane. Li7wt%/
MgO is the most desirable, with a methane conversion of 38% at 720°C and ethylene and ethane selectivity (hereinafter referred to as C2-
They reported that they obtained a selectivity rate of 47%. In addition, Akishika et al. (CheIi.

LctL, 1165 (1988) conducted similar experiments using magnesia-based catalysts supporting various metal oxides, and found that Na 15m o I 96/M g O was the most desirable, with a selectivity of 02-57 at 800°C. %,
It is reported that a C2-yield of 22.4% was obtained. moreover,
According to JP-A-01-207346, a catalyst supporting lead oxide (PbO) or lead oxide and manganese oxide (MnO) is preferable, and the methane conversion rate is 26 at 750°C.
%, C2-selectivity of 41%, and C2-yield of 10.7%. However, none of these can be said to be highly active in terms of catalytic performance.

On the other hand, Adira et al. (59Lh CATSJ Meeting
Ab-sLracts, No. AI 29 No. 2
．． 48. (1987)) used various metal oxide catalysts supported by alkali salts, among which L i 20io
1%/NiO system has the highest activity <, methane conversion rate 26.1% at 750°C, C2-selectivity 55.8
%, C2 ~ yield of 14.6%, and furthermore, it was found that the reactive active species was LiNiO2, but it is reported that the reaction active species was found to be LiNiO2. Composite oxide (
A, M”02 or A2MNO,) have not reached the conclusion that all six effects.Also, with the same legal text, Adiri et al.
a20mo1%/NiO type or K20s
o1%/NiO system activity is low (C2-yield
%), and the presence of NaNiO2 or KNi02 was not confirmed.

According to the invention - the formula AM"02 or A2M"
The aim was not to obtain a 03-type composite oxide, but simply to support 20 mo1% alkali metal on various metal oxides, and to add some consideration to what was effective based on the activity test results. do not have.

Also, G, S, [, anc et al. (Proc, 9t!t I
nL, Congr.

CaLa1.2.944(1,9N)) was studied for LiNiO2 systems with different supported amounts, and Li 18ν
t%/T i Oz system is the most desirable, and its C2
- The yield was 11,5%, but within 48 hours about 17
It has been reported that the activity has decreased to below 5. Moreover, in the same legal text, they state that the reactive species is not Li2Ti03 but Li2Ti03.
It is clearly stated that Ti0□.

In the present invention, the opposite is true for titanium, and L1
□Tie, etc. are considered to be active species, and the appropriate alkali support for TiO2 is also different.

Furthermore, [According to Patent Publication No. Sho GO-502005, an example of a NaMn0210wt%/MgO based catalyst is shown, and although the catalytic activity varies considerably depending on the type of MgO, the most Even the active one has a methane conversion rate of 15.8% at a temperature of 800°C.
, C2-7-selectivity 88, 696.02~7-yield 1
It is reported to be 4.0%. However, this publication does not provide details regarding the types of MgO and what characteristics these MgO have. We also searched related US patents (26), but found no mention of this in any of them.

[Problems to be Solved by the Invention] The fundamental principle of the method for producing hydrocarbons according to the present invention is that the temperature
The so-called "oxidative coupling method of methane" is a method of producing hydrocarbons having 2 or more carbon atoms by contacting methane H-containing gas and oxygen-containing gas at 0 to 1500°C in the presence of a catalyst. However, as described in the previous section, the known techniques have various problems. That is, ■, the conversion rate of methane is low. ■, C2-Selectivity is low.

■, C2=low yield. ■The temperature required for the 0 reaction is high.

There are problems such as these, and the present invention solves these problems all at once.

[Means for solving the problem] The present invention involves the catalytic oxidation of methane-containing gas and oxygen-containing gas at a temperature of 500 to 1500°C in the presence of a catalyst prepared using high-purity ultrafine powder single crystal magnesium oxide. This invention relates to a method for producing hydrocarbons having two or more carbon atoms, such as ethylene and ethane, by coupling, and can solve all of the various problems mentioned above.

In more detail about the catalyst used in the present invention, high-purity ultrafine powder single crystal magnesium oxide is used as a carrier raw material, an alkali metal oxide is added as a second component, and NaCl is added as a third component together with the above magnesium oxide and alkali metal oxide. Vine plus 3 becomes a composite oxide with a type structure
It is characterized in that it is prepared by adding an additive component raw material that is produced after preparing a catalyst, such as an oxide of a metal element having a valence of valence or +4.

The magnesium oxide that is the carrier raw material for preparing the catalyst of the present invention is produced by, for example, bringing magnesium vapor and oxygen-containing gas into contact with each other in a turbulent diffusion state to oxidize magnesium, that is, by a gas phase oxidation method. It has properties such as high purity, ultra-fine powder, single crystal, and high activity (average particle size 0.01-0.2 μm1 purity>99.
98%). The more fine the magnesium oxide raw material is, the more preferable it is to the present invention.

In addition, lithium (Lf), sodium (Na), or potassium is one of the raw materials for additive components for preparing the catalyst of the present invention, and the raw materials for producing the alkali metal oxide, which is a component of the composite oxide after preparing the catalyst, include lithium (Lf), sodium (Na), or potassium. The oxide, hydroxide, carbonate, nitrate, acetate, alkoxide or acetylacetonate of (K) is used. By adding these alkali metal oxides to the catalyst, the C2 yield increases dramatically.

The raw materials for producing after catalyst preparation an oxide of a metal element with a valence of +3 or 4 which can form a composite oxide with an NaCl type structure together with the above-mentioned magnesium oxide and alkali metal oxide include one or more of these metal elements. Oxides, hydroxides, nitrates, acetates, alkoxides or acetylacetonates are used. By adding these metal oxides to the catalyst, a composite oxide having an NaCl type structure is formed together with the alkali metal oxide described above, and becomes a catalytically active species.

Examples of positive trivalent metal elements that can form a composite oxide with the NaCIW structure together with the above magnesium oxide and alkali metal oxides include vanadium (■) and chromium (Cr).
, manganese (M n ), iron (Fe) cobalt (
Co), nickel (Ni), gallium (Ga),
Yttrium (Y) and indium (In) can be mentioned, and examples of positive tetravalent metal elements include titanium (TK), manganese (M n ), germanium (Ge), zirconium (Zr), and tin ( Sn),
and hafnium (J(f)).

After preparing the catalyst, these raw materials for additive components for catalyst preparation have an atomic ratio A/M of 1 between the alkali metal element (A) and the trivalent metal element (Ml), which forms a composite oxide with an NaCl type structure. or so that the atomic A/M'v of the alkali metal element (A) and the positive tetravalent metal element (M") which can form a composite oxide of NaCl type structure is 2, After catalyst preparation, each AM” 0
2 or A 2 M''03 is generated.

Also, the amount of high-purity ultrafine powder single crystal magnesium oxide is catalyst: A? ! Later, it is formulated to have a concentration of 5% or more and 95% or less. The catalyst may be prepared according to a commonly used method, but to explain in more detail, it is preferable to follow the following method.

First, an alkali hydroxide is added to the aqueous solution of the +3-valent or +4-valent metal salt to precipitate each hydroxide, and after thoroughly washing with water, the hydroxide is suspended in water. The alkali salt is added to this so that the atomic ratio of A/M" is -1 or A/M"-2, and the mixture is evaporated to dryness with stirring, and then fired.

AM'02 type or A2MN obtained in this way
03 Type Composite Oxide Color In order to prepare a NaCl type composite oxide with magnesium oxide, the two are mixed at the above weight ratio, suspended in an organic solvent such as ethyl alcohol, and evaporated with thorough stirring. After drying, it is fired.

Further, in the method for producing ethylene and other hydrocarbons according to the present invention, a methane-containing gas such as dry natural gas and an oxygen-containing gas such as air are subjected to a catalytic reaction in the presence of the above catalyst. The reaction is usually carried out continuously by introducing the above-mentioned mixed gas mixed with a diluent gas such as He, N2, Ar, etc. as necessary into a tubular flow reactor (fixed bed type) filled with a catalyst. The reaction pressure is generally normal pressure to 20 kgr/cd G
, preferably normal pressure to 5 kgr/cJ G, and reaction temperature 500 to 1500°C, preferably 650 to 85
It is carried out at 0°C.

Incidentally, a fluidized bed reactor or the like can also be used as the reaction apparatus, and the reactor is not limited to the above-mentioned fixed bed reactor. By performing oxidative coupling of methane-containing gas in this manner, hydrocarbons such as ethylene can be produced with a small amount of catalyst and at a relatively low temperature with a high conversion rate and high selectivity.

[Effect] Already high-purity ultrafine powder single crystal magnesium oxide with alkali metal oxide (A70) and atomic number 21 (Sc) ~ 2+1
(Ni) or atomic number 57 (La) to 71. c,
It was discovered that a catalyst supporting a metal element oxide (M''20i) that can have a positive trivalent valence of L u,
No. 7), but the reason is that A
It is thought that M"O7 is formed and forms a solid solution in MgO, which has the same NaCl type structure, promoting the oxidative coupling reaction of methane.Based on this, further intensive studies revealed that the alkali metal Magnesium oxide based composite oxide (AM"O□ or A2M"0., respectively) consisting of an oxide (A20) and a positive trivalent or positive tetravalent metal element oxide (M1□03 or MlvO2, respectively) It has been found that the catalyst is extremely effective for the oxidative coupling reaction of methane.

[Example] Examples and comparative examples are shown below.

Examples 1 to 9 First, a method for synthesizing an AM″0□ type composite oxide will be described.

LiCr0. , LiMn0□, LiFeO2, LiCo
0. LiNiO2 is a nitrate aqueous solution (Cr (NO
3) 3 ・9H20, Mn (NOx)-
6H20, Fe (NO3) 2 '982 0
sCo (NO3) 2 ・6H20, N j
Add lithium hydroxide to (NO3) 2 ・6H20) to precipitate each hydroxide, wash thoroughly with water, suspend this hydroxide in water, and add lithium nitrate to it.
M was added so that the atomic ratio was 1, and the mixture was evaporated to dryness with stirring. This was prepared by firing at 400°C and further firing at 800°C for 4 hours. Moreover, Li1nO, is 1. Wako In 203 (99.9% purity) and lithium nitrate were added to water so that the Li/In atomic ratio was 1, and mixed well and evaporated to dryness.
It was fired at 800°C for 4 hours.

On the other hand, NaFeO2, NaNf021. NaInk2 was prepared in the same manner as above using sodium hydroxide instead of lithium hydroxide and sodium nitrate instead of lithium nitrate. In both cases, it was confirmed by XRD that the oxides after firing at 800°C turned into the desired composite oxides.

These AM" O□ type composite oxides and high-purity ultrafine powder single crystal magnesium oxide (average particle size 0.08 μm) were suspended in ethyl alcohol mixed at a weight ratio of -1, and evaporated to dryness with thorough stirring. After that, it was baked at 800°C for 4 hours.

These AM''02/MgO-based catalysts 0.1.
:3 mixed gas was passed under the conditions of 50 ml/mln, lat*.

Analysis of the products obtained at reaction temperatures of 600°C to 900°C using gas chromatography revealed that ethylene, ethane, a small amount of propylene, carbon dioxide,
- Carbon oxide, water.

Table 1 shows the results at the reaction temperature at which the C2-hydrocarbon production rate showed the highest value.

Table 1 Examples 10 to 17 L i 2 T i O), L l 2 Z r O
5L l 2SnOt is prepared by adding titanium tetrachloride, zirconium tetrachloride, and tin tetrachloride to water, then neutralizing it with lithium hydroxide, thoroughly washing the generated hydroxide with water, and mixing the hydroxide with lithium nitrate in a molar ratio of 1: 2 (Li/M atomic ratio -2) was suspended in water and evaporated to dryness with stirring. This dried product is 4
After firing at 00°C, it was further fired at 800°C for 4 hours.

Li2Hf0. and Li2GeO3 are hafnium oxide (97%) or germanium oxide (99,99%) manufactured by Wako.
9999%) was added with a desired ratio of lithium nitrate, suspended in water, and evaporated to dryness with thorough stirring, then calcined at 400°C and further calcined at 800°C for 4 hours.

On the other hand, Na, 2Tie, Na2ZrO,, Na25
nO, is sodium hydroxide instead of lithium hydroxide,
It was prepared in the same manner as above using sodium nitrate instead of lithium nitrate.

It was confirmed by XRD that all the oxides were the desired composite oxides.

These A2MNO* type composite oxide colored high-purity ultrafine powder single crystal magnesium oxide (average particle size 0.05 μm) were mixed at a weight ratio of -1, suspended in ethyl alcohol, dried with thorough stirring, and then heated at 800°C. It was baked for 4 hours.

The catalyst activity evaluation test was conducted under the same conditions as Examples 1 to 9.

Table 2 shows the results at the reaction temperature at which the C2-hydrocarbon production rate showed the highest value.

Table 2 Examples 18 to 24 LiNiO2, LtlnO2 or Li25nO, and high purity ultrafine powder single crystal magnesium oxide (average particle size 0.0
5μm) and the formulation ff1m ratio is 10 no 9Q, 20780
Or Example 6 except that it was changed to 80/20.
8 or 16.

The catalyst activity evaluation test was conducted under the same conditions as Examples 1 to 9.

Table 3 shows the results at the reaction temperature at which the C2-hydrocarbon production rate was highest.

(, Ill 7 F-11,03t -h/sip) Table 3 Comparative Examples 1 to 3 Aqueous ammonia was added to an aqueous solution of magnesium nitrate to obtain magnesium hydroxide, which was fired at 800°C to produce liquid phase-ruptured magnesium oxide (average A particle size of 0.02 μm) was obtained. 50%LiNiO2-50% liquid phase MgO
A system catalyst was obtained.

In addition, 50%
%LiNiO2-50%5i02 type catalyst was obtained.

Furthermore, an activity evaluation test was conducted under the same conditions as in Examples 1 to 3 using these 38 catalysts, including high-purity ultrafine powder single crystal magnesium oxide (average particle size 0.05 μm) and a catalyst with no support.

Table 4 shows the results at the reaction temperature at which the C2-hydrocarbon production rate showed the highest value.

Table [Effects of the Invention] As is clear from the above description, the following effects can be achieved by producing a hydrocarbon having 2 or more carbon atoms according to the method of the present invention.

■High conversion rate of methane. ■, C2-high selectivity.

■High C2-yield. (1) The temperature required for reaction is extremely low.

Claims (2)

[Claims] (1) In a method (oxidative coupling) of producing a hydrocarbon having 2 or more carbon atoms by contacting a methane-containing gas and an oxygen-containing gas at a temperature of 500 to 1500°C in the presence of a catalyst, [1] High-purity ultrafine powder Single crystal magnesium oxide [2] Alkali metal oxide [3] A composite oxide catalyst consisting of an oxide of a positive trivalent metal element that can form a composite oxide with a NaCl type structure together with the above magnesium oxide and alkali metal oxide is used. A method for producing a hydrocarbon having 2 or more carbon atoms, characterized in that: (2) In a method for producing a hydrocarbon having two or more carbon atoms by contacting a methane-containing gas and an oxygen-containing gas at a temperature of 500 to 1500°C in the presence of a catalyst, [1] High-purity ultrafine powder single crystal magnesium oxide [ 2) Alkali metal oxide [3] A composite oxide catalyst consisting of an oxide of a positive tetravalent metal element that can form a composite oxide with an NaCl type structure together with the above magnesium oxide and alkali metal oxide is used. A method for producing hydrocarbons having 2 or more carbon atoms.