JPH01233242A - Hydrogenation of carbon monoxide - Google Patents

Abstract

PURPOSE:To obtain an alcohol useful as fuel for automobiles, etc., in high selectivity and in high yield, by reacting CO with H2 by using an indium carrying catalyst having raised activity of indium catalyst by specific treatment to efficiently carry out hydrogenation of CO. CONSTITUTION:CO is hydrogenated at 200-400 deg.C at GHSV=5,000-50,000/h under 20-300kg/cm<2> in the presence of an indium carrying catalyst such as no indium catalyst supported on alumina or indium composite catalyst supported on alumina treated with CO and H2 or a catalyst obtained by treating a prepared indium carrying catalyst with CO and H2 and hydrogenating to give an alcohol. The indium carrying catalyst is prepared by dissolving a water-soluble indium compound and a compound to be optionally added and to become a promoter component in water, impregnating a carrier such as alumina with the aqueous solution, concentrating, drying in air, thermally decomposing at >=20 deg.C and then reducing with hydrogen.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for hydrogenating carbon monoxide, a method for producing alcohol from carbon monoxide, and a method for treating catalysts used therein.

Prior Art Iridium catalysts have generally been considered very low activity methanation catalysts (Catal, Rev., 8.159).
(1973) and J, Catal, 37.449 (
1975)), was also known to exhibit methanol synthesis activity under extremely high pressure;
U, Catal, which shows more than twice the lower activity, 52.
157 (1987)).

The present inventors have also discovered and reported that an alumina-supported iridium composite catalyst exhibits high activity in alcohol synthesis.

Problems to be Solved by the Invention The present invention aims to increase the conversion rate of carbon monoxide or the yield of alcohol when hydrogenating carbon monoxide using an iridium-supported catalyst. Also,
Another object of the present invention is to provide a method for treating an iridium-supported catalyst with enhanced carbon monoxide hydrogenation activity and alcohol production activity.

Means for Solving the Problems The present invention provides a method for hydrogenating carbon monoxide or a method for producing alcohol by reacting carbon monoxide and hydrogen in the presence of an iridium-supported catalyst that has been subjected to a reaction treatment with carbon monoxide and hydrogen. Another invention is a method for treating a carbon monoxide hydrogenation catalyst, in which a prepared iridium-supported catalyst is subjected to a reaction treatment with carbon monoxide and hydrogen, and then subjected to a hydrogen reduction treatment.

The iridium-supported catalyst may be one in which iridium or an iridium compound such as iridium oxide is supported on a support such as alumina, and a promoter component such as a group 6 metal or a compound thereof may be added thereto.

Co-catalyst components include molybdenum, vanadium, chromium,
There are rhenium, tungsten, zirconium, manganese, lanthanum, etc., and the alcohol production activity increases according to this order. For example, a molybdenum-added catalyst exhibits about 300 times the activity of an iridium monocatalyst. Furthermore, the promoter component is 2
The above may be added, such as alkali metals, alkaline earth metals,
Compounds such as rare earth metal oxides may be used in combination with co-catalyst components as described above. The amount of iridium supported is 1 to 10%, preferably 2 to 5% as metallic iridium.
% is appropriate. When adding molybdenum, chromium, etc., the appropriate amount of iridium is within the above range; for molybdenum, chromium, etc., the amount is 0. A range of 1 to 10% is suitable. Examples of suitable catalyst compositions include 3% Ir/alumina,
3% Ir-5% Mo-1, 25% Na, O/alumina,
Examples include 3% Ir-0.5% Mo/alumina.

The iridium-supported catalyst can be prepared, for example, as follows. A water-soluble iridium compound and a compound added as a co-catalyst component are dissolved in water,
After impregnating a carrier such as alumina, concentrating and air drying, 2
The catalyst is thermally decomposed at a temperature of 00°C or higher, preferably 250 to 700°C, and then subjected to hydrogen reduction treatment to form a catalyst. The hydrogen reduction treatment is carried out at 200-700°C, preferably at 3°C in a hydrogen stream.
It is preferable to carry out the heating at a temperature of about 00 to 500°C for about 5 minutes or more.

The prepared iridium-supported catalyst is subjected to a reaction treatment with carbon monoxide and hydrogen.6 The reaction treatment refers to the reaction of carbon monoxide and hydrogen in the presence of this catalyst.In this reaction treatment, the conversion rate of carbon monoxide is is usually extremely low, but by repeating this reaction treatment it gradually increases until it finally shows a higher conversion rate than the palladium catalyst.200
~400°C, preferably 300-350°C, GH3V=
5000~50000/h, 20~300Kg/cd,
It is preferable that H,7GO=about 2.The optimum reaction treatment conditions are generally those that give the highest yield, but these vary depending on the catalyst. The reaction treatment time is 1 hour or more, preferably 5 hours or more, and this is preferably performed at least once, preferably 2 or more times.Furthermore, after one reaction treatment is completed, hydrogen reduction as described above is then carried out. It is preferable to carry out the treatment in order to maintain a good surface condition of the catalyst.

Carbon monoxide and hydrogen are reacted using the catalyst treated as described above. The reaction conditions may be similar to the reaction treatment conditions described above. The composition of the raw material synthesis gas is H2/C0=2
The yield of alcohol such as methanol can be maximized by adjusting the amount of alcohol before or after that. Furthermore, when the reaction temperature is raised, the space-time yield of alcohol increases, but the selectivity decreases.

7JL, the main component of coal is usually methanol,
By selecting the catalyst and conditions, the proportion of alcohol with a large number of carbon atoms such as ethanol can be increased.

Such alcohol mixtures are suitable for applications such as automobile fuels. In addition, oxygen-containing compounds 1 such as dimethyl ether and hydrocarbons such as methane can be produced.

It is thought that by subjecting the active iridium catalyst to a reaction treatment, new active sites appear, thereby improving activities such as alcohol production activity.

Examples Example 1 After dissolving the catalyst component in a predetermined amount of water (1 ml/1 g of alumina), it was impregnated into an alumina support obtained by baking Bayer method gibbsite at 900°C, concentrated on a 60°C water bath, and then heated to room temperature. It was air-dried.

This was thermally decomposed in air at 250°C for 10 minutes, brought to ambient temperature at 200°C/h to 400°C in a hydrogen stream, maintained for 10 minutes, and reduced to prepare a catalyst. Using these conditions as standard, we also investigated catalysts prepared by changing thermal decomposition conditions, reduction conditions, etc. As a catalyst component, IrCl4 Hz
O was used.

Using a fixed bed pressurized flow reactor, 0.3 ml of this catalyst was filled into a stainless steel tube with an inner diameter of 7 mm, and H! /C0=2
．． The reaction was carried out under the conditions of 5V=15000/h and 86Kg/-. Figure 1 shows the temperature increase/decrease program.

In order to keep the surface reduction state constant, hydrogen reduction was performed again in the reaction tube (heated to 400°C at 200°C/h in a hydrogen flow of 40ml/min and held for 10 minutes), then cooled to room temperature. After replacing the atmosphere with nitrogen, the atmospheric gas was switched to synthesis gas, the temperature was increased to 230°C at a rate of 10°C/min, and the gaseous products were analyzed about 1 hour after reaching steady state. Thereafter, the analysis was repeated by increasing the reaction temperature one after another, and finally the catalyst performance was measured at each temperature up to 350°C.

The analysis was also conducted at 250° C. when the temperature was lowered. The above reaction treatment and hydrogen reduction were performed as one cycle, and after this was performed once, the reaction was performed at 250°C.

Note that the analysis was performed by gas chromatography. The conditions and results are shown in Table 1.

Table 1 *Note: STY is the space-time yield of alcohol, Alc, is alcohol, with the majority (90% or more) being methanol, D, [! , is dimethyl ether, Met is methane, 11. c, is a hydrocarbon other than methane, C,! +
, is chloromethane.

Example 2 3% Ir/alumina catalyst prepared as in Example 1 (Ir source 1ra(co)+z) and 3% Ir
-0.5% Cr/Alumina catalyst (Ir source ■r CI4・
The same reaction treatment was performed for 6 or 7 cycles for the Hl 2 O, Cr source CNH4) 2 Crz Ol), and the gaseous reaction products at 250° C. in each cycle were analyzed. The results are shown in FIGS. 2 and 3.

For comparison, Pd/alumina catalyst (Pd source pdcl
The reaction was carried out in the same manner except for using
As compared to the previous conversion rate of 0°48.5TY22.3, almost no improvement was observed due to the reaction treatment.

Effects of the Invention According to the present invention, carbon monoxide can be efficiently hydrogenated using an iridium catalyst. Moreover, alcohol can be manufactured with high productivity.

Furthermore, the activity of the iridium catalyst can be significantly increased.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of reaction treatment, and FIGS. 2 and 3 are diagrams showing the relationship between the number of reaction treatments and space-time yield. Patent applicant: Tomoyuki Inui, Nippon Steel Chemical Co., Ltd.

Claims (1)

[Scope of Claims] 1. A method for hydrogenating carbon monoxide, which comprises reacting carbon monoxide and hydrogen in the presence of an iridium-supported catalyst that has been subjected to a reaction treatment with carbon monoxide and hydrogen. 2. A method for hydrogenating carbon monoxide, which comprises subjecting an iridium-supported catalyst that has been reacted with carbon monoxide and hydrogen to a hydrogen reduction treatment, and then reacting carbon monoxide with hydrogen. 3. A method for producing alcohol, which comprises reacting carbon monoxide and hydrogen in the presence of an iridium-supported catalyst that has been subjected to a reaction treatment with carbon monoxide and hydrogen. 4. A method for treating a carbon monoxide hydrogenation catalyst, which comprises subjecting the prepared iridium-supported catalyst to a reaction treatment with carbon monoxide and hydrogen, and then subjecting it to a hydrogen reduction treatment. 5. The treatment method according to claim 5, wherein the iridium supported catalyst is an alumina supported iridium catalyst or an alumina supported iridium composite catalyst.