JPS6130688A - Production of hydrocarbon - Google Patents

Abstract

PURPOSE:To produce easily hydrocarbon having many carbon atoms by heating a vessel which is segmented by a solid electrolyte formed with gas-permeable metallic electrodes on both surfaces to an adequate temp. and supplying lower hydrocarbon to one of the above-mentioned segmented chambers and oxygen to the other. CONSTITUTION:The vessel 1 is segmented to two chambers 5a, b by the solid electrode 2 such as stabilized zirconia and the gas-permeable metallic electrodes 3, 3' consisting of silver, platinum, etc. are formed on both surfaces thereof. A catalyst layer 4 for oxidizing dehydrogenation consisting of bismuth oxide, etc. is further formed on the electrode 3 if necessary. The vessel 1 is heated to 300-1,000 deg.C under or without the impression of voltage to the electrolyte 2 from a voltage impressing device 6 via the above- mentioned electrodes 3, 3'. The lower hydrocarbon such as methane or the gas contg. the same and oxygen or the gas contg. the same are admitted through introducing pipes 1c, d into the chambers 5a, b respectively. The oxygen passes the electrode 3' and arrives at the electrolyte 2, by which the oxygen is ionized to O<2->. The oxygen ions migrate toward the electrode 3 side and oxidizes and dehydrogenates the hydrocarbon. The hydrocarbon such as olefin having more carbon atoms than the carbon atoms of the lower hydrocarbon is thus formed.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for producing a hydrocarbon having a carbon number greater than that of the hydrocarbon by an oxidative dehydrogenation reaction from a lower hydrocarbon. , relates to a novel method for producing hydrocarbons in which the oxidative dehydrogenation reaction is carried out using an electrode reaction of a solid electrolyte.

[Technical background of the invention and its problems]

A method is known in which lower hydrocarbons such as methane and ethane are reacted with oxygen in the presence of a well-known oxidative dehydrogenation catalyst or oxidation catalyst to dehydrogenate them to produce hydrocarbons with a larger number of carbon atoms.

Regarding the oxidation of these lower hydrocarbons, for example, in the electrode reaction of oxygen ion conductive solid electrolytes such as stabilized zirconia in the field of fuel cells, one of the fuels, such as methane and ethane, is oxidized and finally It is a well-known fact that gas changes into water and carbon dioxide.

More recently, a method has been reported in which olefins such as ethylene and propylene are oxidized to produce epoxides using an oxygen ion conductive solid electrolyte (E
electrochemical modification
n of the Activity and 5el
ecti-vity of 5ilver for I
, light Qlefin Oxidation.

M, 5tonkides, C, G, Vayena
s, 8th, International-onal C
ongress on Catalysis 'Vol.
IV 827 (1984)).

In this way, methane,
Methods for oxidizing lower hydrocarbons such as ethane are well known.

However, little is known of a method for proceeding with an oxidative dehydrogenation reaction using a solid electrolyte and, as a result, producing a hydrocarbon having a carbon number greater than that of the lower hydrocarbon from a lower hydrocarbon.

[Purpose of the invention]

The present invention aims to provide a novel method for producing olefins from lower hydrocarbons to hydrocarbons with a larger number of carbon atoms, such as methane, by utilizing the electrode reaction of a solid electrolyte. [Summary of the Invention] The present invention The method for producing hydrocarbon 1 is a method for producing a hydrocarbon having a carbon number greater than or equal to that of the lower hydrocarbon by an oxidative dehydrogenation reaction of the lower hydrocarbon, and includes gas-permeable metal electrodes on both sides. In a container divided into two compartments by the formed solid electrolyte, one compartment contains the lower carbonization at a temperature of 300 to 1000 C with or without applying a voltage to the solid electrolyte. It is characterized in that hydrogen or a lower hydrocarbon-containing gas is introduced into the fraction chamber, and oxygen or an oxygen-containing gas is introduced into the other fraction chamber to proceed with the reaction. In this case, oxygen is ionized by the solid electrolyte and hydrocarbons are oxidized by oxygen ions.

The method of the present invention will be explained in more detail below using the example of the apparatus shown in FIG. 1 used when carrying out the method of the present invention.

In FIG. 1, 1 is the entire reaction vessel, and 1a is a pipe for discharging hydrocarbon gas produced as a result of the reaction described below.

1b is a lead-out pipe for oxygen or oxygen-containing gas used in the reaction, and a valve mechanism (not shown) is attached to each pipe.

Container 1 contains solid electrolyte 2. Gas permeable metal electrode 3.3
', the catalyst layer 4 for oxidative dehydrogenation is divided into two chambers 5a and 5b by an electrode section formed by integrally stacking them.

A lower hydrocarbon to be oxidized and dehydrogenated or a gas containing it flows into the fraction chamber 5a from a lower hydrocarbon inlet pipe 1c equipped with a flow valve (not shown).
Oxygen or a gas containing oxygen is introduced into the tube b from an oxygen introduction pipe 1d equipped with a flow valve (not shown).

In the above-mentioned electrode section, the solid electrolyte which is the main part thereof may be of any material as long as it has ionic conductivity, for example, zirconia.

Examples include thoria, bismuth oxide, nitride oxide, and stabilized zirconia. In particular, (ZrOz)(
Stabilized zirconia represented by 1,6(Y2O2) 6.1 is suitable because it has high ionic conductivity (2X10-2Ω-'cWL-'') at high temperatures (800tll').

On both sides of this solid electrolyte 2, gas permeable metal electrodes 3,
3' is attached, and the electrodes are connected to the voltage applying device 6 using, for example, a platinum wire as a conducting wire. Examples of metals used for electrodes include silver.

Platinum is preferred. For example, in the case of silver, the impregnation method is to suspend oxidized powder in acetone or the like, apply this suspension to both sides of the solid electrolyte, and then apply the entire solid electrolyte to a
An example is a method of baking silver by heating at 0C or higher. It is also preferable to carry out the reaction in a reducing atmosphere.

A catalyst layer 4 for oxidative dehydrogenation can be formed on the metal electrode 3 on the side of the fraction chamber 5a in order to control activity and selectivity. The catalyst used in this layer may be any conventionally known catalyst, such as bismuth, tin,
Examples include lead, antimony, thallium, cobalt, cadmium, manganese, molybdenum, iron, chromium, magnesium, and composite oxides thereof. The catalyst layer can be formed by applying a solution of the above-mentioned metal in an aqueous solution or an organic solvent and then baking it.

In proceeding with the reaction, the temperature of the entire apparatus, especially the electrode part, should be kept at 300 to 1000C, preferably 400 to 750C.
maintain it. If the temperature is less than 300C, the ionic conductivity of the solid electrolyte will be low and the reaction described below will not proceed quickly, and if it exceeds 1000C, the solid electrolyte will deteriorate and its ionic conductivity will disappear again. .

Next, reaction gases are introduced into the fraction chambers 5a and 5b, respectively. The gas flowing into the fraction chamber 5a is a lower hydrocarbon such as methane or ethane, or a mixed gas prepared by diluting these with an inert gas such as helium. Further, the gas flowing into the fraction chamber 5b is oxygen or an oxygen-containing gas such as dry air. The inflow amount of these gases is
The valve mechanisms of each inlet pipe and each outlet pipe are operated and adjusted. Particularly, the pressure in the fraction chamber 5a is normal pressure to 10 kg/c.
It is preferable to adjust it so that it becomes m''.

The oxygen flowing into the fraction chamber 5b passes through the gas-permeable metal electrode 3' and reaches the solid electrolyte 2, where it is ionized and moves within the solid electrolyte toward the other metal electrode 3. That is, ion conduction of O begins. At this time, an electromotive force corresponding to the difference in chemical potential between lower hydrocarbons and oxygen present in the fraction chambers 5a and 5b is generated between the metal electrodes 3° and 3'. As a result, the metal electrode 3 becomes
The metal electrode 3' becomes the θ pole. A predetermined current flows through the lead wire and the voltage application device that connect the two electrodes.

The oxygen ions that have moved to the metal electrode 3 side oxidize and dehydrogenate the lower hydrocarbons in the fraction chamber 5a through the action of the metal electrode or the action of the catalyst layer 4 formed on the metal electrode 3. This reaction proceeds without applying a voltage between the metal electrodes 3 and 3', but a predetermined voltage may be applied between the two electrodes. In the latter case, the amount of hydrocarbons produced varies.

We believe that this is because the amount and speed of oxygen ions moving within the solid electrolyte 2 change due to voltage application, and the state of the oxidation and dehydrogenation reaction within the fraction chamber 5a is subtly affected. It will be done.

Although the above explanation has been made based on the example of the apparatus shown in FIG. 1, the apparatus used in the method of the present invention is not limited to this.

For example, a structure as shown in FIG. 2 may be used.

[Embodiments of the invention]

Examples 1 to 3 A single-sealed tube of stabilized zirconia group having an inner diameter of 30 mm, a length of 30 mm, and a wall thickness of 2.5 mm was prepared. An acetone suspension of silver oxide powder was applied to the inner and outer surfaces of this single-sealed tube over a length of 80 m from the sealed portion.

Then, it was treated in air at 250C for 2 hours to form silver electrodes on the inner and outer surfaces. Bismuth oxide powder was deposited on the silver electrode on the outer surface of the tube to form a catalyst layer.

This is referred to as Example 1 sample.

In place of bismuth oxide, catalyst layers of bismuth oxide-molybdenum oxide and cobalt oxide-magnesium oxide were produced in the same manner, and these were used as Example 2 samples and Example 3 samples, respectively. Note that a sample without a catalyst layer was also produced and designated as Example 4.

Using these four types of electrode sections, a device as illustrated in Fig. 2 was assembled, and 20 cc/m of dry air was introduced into the inside of the tube (fraction chamber 5b), and the outside of the tube (fraction chamber 5a). include methane 2DvoQ%, helium 8QvoQ
% mixed gas was flowed in at 20 CC/ml11 and the overall temperature was maintained at 700 t:'.

The generated gas obtained from the outlet pipe 1a was analyzed, the conversion rate was calculated, and the selectivity to ethane and ethylene was measured.

The above results are shown in Table 1.

Table 1 Example 5 In Example 1, the reaction was carried out by maintaining the temperature at 650C and applying various voltages between the silver electrodes. The results are shown in Table 2.

Table 2 Example 6 In Example 1, a shite reaction was carried out by applying various voltages between the silver electrodes. The results are shown in Table 3.

Table 3 [Effects of the Invention] As is clear from the above explanation, the method of the present invention is a novel method for producing hydrocarbons having a carbon number greater than that of lower hydrocarbons from lower hydrocarbons by utilizing the electrode reaction of a solid electrolyte. This method is expected to be useful as a method for cumulatively producing C1 or higher hydrocarbons from methane, for example, and has great industrial value.

[Brief explanation of drawings]

FIG. 1 and FIG. 2 both show examples of apparatus used in the method of the present invention.

Claims (1)

[Claims] A method for producing a hydrocarbon having a carbon number greater than that of the lower hydrocarbon by an oxidative dehydrogenation reaction of the lower hydrocarbon, the method comprising using a solid electrolyte having gas-permeable metal electrodes formed on both sides. Therefore, in a container divided into two chambers, the solid electrolyte was heated for 30 minutes with or without applying a voltage.
At a temperature of 0 to 1000°C, the lower hydrocarbon or lower hydrocarbon-containing gas is flowed into one fraction chamber, and oxygen or an oxygen-containing gas is flowed into the other fraction chamber to proceed with the reaction. A method for producing hydrocarbons.