JPS5865232A - Preparation of ethanol - Google Patents

Abstract

PURPOSE:To obtain ethanol in high selectivity in reacting methanol with CO and H2 in the presence of a catalyst containing Co, Ru and I as active constituents, by the presence of an aromatic hydrocarbon in the reaction system. CONSTITUTION:Methanol is reacted with CO and H2 in the presence of a catalyst containing Co, Ru and I as active constituents and further an aromatic hydrocarbon e.g. benzene, toluene or mixed xylene, at 130-200 deg.C to give ethanol. The amount of the aromatic hydrocarbon to be used is 0.1-10mol based on one mole methanol. The presence of a little water in an amount of 2mol or less based on one mole methanol in the reaction system reduces the formation of ether as a by-product and is effective for increasing the selectivity of the ethanol. EFFECT:The catalyst is easily recovered, and low-grade methanol containing water can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for selectively producing ethanol from methanol, carbon monoxide, and hydrogen.

Conventionally, methods for producing ethanol from methanol, carbon monoxide, and hydrogen generally include cobalt and iodine or bromine as active ingredients as catalysts, and if necessary, ruthenium, osmium compounds, and various coordination compounds. A method is known in which children are used in combination.

For example, Japanese Patent Publication No. 5B-24863 discloses a method in which methanol, carbon monoxide and hydrogen are reacted in the presence of a cobalt catalyst and an iodine promoter.

Also, US Special Fraud No. 3,285,948 is a soluble cobalt compound. This is a method in which methanol, carbon oxide, and hydrogen are reacted in the presence of iodine or iodide and a ruthenium compound catalyst.

Recently, catalyst systems have been proposed in which various ligands such as tertiary phosphine, tertiary antimony, and tertiary arsine are combined in addition to the above catalysts as promoters. For example, JP-A-51-1
49215 is methanol using a hydrocarbon as a solvent in the presence of a cobalt-halide-tertiary phosphine catalyst.

-This is a method of reacting carbon oxide and hydrogen.

JP-A-54-73708 describes aryl halide, ether in the presence of cobalt-iodine or bromine-tertiary phosphine or tertiary amine catalyst.

This method uses inert solvents such as thiophene, long chain acids, aromatic acids, or silicone oil.

JP-A-55-49326 discloses a method in which the reaction is carried out in the presence of a cobalt-iodine or bromine-nitrogen catalyst or a polydentate ligand containing a phosphorus atom.

British patent 2,056,739 describes cobalt and 25.8-
,of.

, , ga□Good 5 U□Eh. Yo. , A6. . gate 4
This is a method in which the reaction is carried out in the presence of ni-14-3 phosphine, tertiary antimony, or 6-arsine.

% Open Showa 55-92330 is a hydridocobalt carbonyl complex, iodine, and a ruthenium compound.

and a method of reacting in the presence of a catalyst containing 6th phosphine, 6th antimony, or tertiary arsine as an active ingredient.

U.S. Pat. No. 4,233,466 describes cobalt.

Using a catalyst system consisting of ruthenium, iodine, and tertiary phosphine, P/I (molar ratio) = 1:0, 36
-1:5, P/Co (molar ratio) = 1.5 or more.

However, when we examined the application of the method using the existing catalyst system represented above to an industrial ethanol production method, we found that in addition to the target ethanol, dimethyl ether, methyl ethyl ether, diethyl ether, acetaldehyde, dimethoxy Ethane. Acetic acid. Methyl acetate.

A large number of by-products such as ethyl acetate, methyl formate, and other compounds with Cs or higher are generated simultaneously, making it difficult to selectivity to 9-ethanol as an industrial catalyst, especially when used in combination with a ligand. It was found that there were various problems.

That is, Japanese Patent Publication No. 3B-24863, or U.S. Pat.
, 285,948. As mentioned above, cobalt-iodine,
Or in the presence of a catalyst containing cobalt-iodine-ruthenium as an active ingredient, without a solvent, at a reaction temperature of 175 to 230'C.
, is a method in which methanol is reacted with carbon monoxide and hydrogen at a pressure of 281 and 9/cd or more, and this catalyst is excellent in ease of handling since no ligand is used in combination.

According to studies conducted by the present inventors, among the above-mentioned by-products, ethers and methyl acetate are particularly produced, and the selectivity to free ethanol is extremely low.

On the other hand, in the method in which the above-mentioned catalyst and various ligands are combined, the by-product of ethers tends to be suppressed, but the addition of the ligand reduces the catalytic activity, so the reaction temperature has to be increased. The result is acetaldehyde, dimethoxyethane, acetic acid, and methyl acetate. Ethyl acetate. Methyl formate. Others 01
There are many by-products such as the above compounds, and it cannot be said that the selectivity to ethanol is necessarily high. In particular, in these methods, in addition to Hupart and ruthenium, iodine or bromine,
and tertiary phosphine, 6th antimony as a ligand,
Alternatively, the use of a plurality of tertiary arsine etc. causes various problems industrially as follows. In other words, according to the inventor's study, ligands such as the sixth phosphines are thermally unstable and are likely to be decomposed or altered in the reaction system, leaving the active species of the catalyst intact. It is extremely difficult to collect and reuse it. Moreover, even if method 5= of recovering each catalyst component is adopted, the catalyst system is complicated, so complicated steps are required, and the loss associated with recovery is large.

Since it is expensive, it has the disadvantage of increasing catalyst costs.

As described above, all of the known methods have problems in the selectivity of ethanol, the reaction rate, and the recovery and reuse of the catalyst system, and cannot be said to be industrially satisfactory.

As a result of extensive research in order to avoid various drawbacks of conventional methods, the present inventor has discovered that when reacting methanol with carbon monoxide and hydrogen in the presence of a catalyst containing cobalt, ruthenium, and iodine as active ingredients, The inventors have discovered that the selectivity to ethanol can be improved by allowing aromatic hydrocarbons to coexist in the reaction system, and have completed the present invention.

That is, the present invention is a method of using a cobalt-iodine-ruthenium catalyst and reacting methanol with carbon monoxide and hydrogen in the presence of an aromatic hydrocarbon in one reaction system.

6- The aromatic hydrocarbon used in the present invention is benzene,
Toluene, O + rn + p-xylene, mixed xylene, ethylbenzene, 1,2.3=trimethylbenzene, 0-methylethylbenzene, 0-diethylbenzene, isopropylbenzene, etc., but especially benzene,
toluene.

and mixed xylenes are preferred. The amount of aromatic hydrocarbon used is 0.02 to 20 mol, preferably 0.1 to 10 mol, per 1 mol of methanol. 0.
If it is less than 0.02 moles, the effect will be small, and if it is more than 20 moles, the space-time yield will be small, so the above range is practical.

In the present invention, it is preferable to have some water present in the reaction system since this has the effect of reducing the by-product of ether and increasing the selectivity of ethanol. In this case, the amount of water added is methanol 1
, , is in the range of 2 moles or less per 1 mole of Nyl. When 2 moles or more is added, the by-product of acetic acid or methyl acetate increases, and the selectivity to ethanol decreases.

The catalyst used in the present invention is cobalt.

This is a catalyst system containing ruthenium and iodine as active ingredients. Cobalt and ruthenium are metallic cobalt, metallic ruthenium, and various compounds thereof, and any material containing cobalt and ruthenium can be used. For example, cobalt compounds include: cobalt iodide, cobalt bromide, cobalt chloride, cobalt pseudoacid, cobalt formate, cobalt acetate/cobalt unaphthenate, cobalt acetylacetonate, cobalt carbonyl, and the like. Ruthenium compounds include potassium iodide, ruthenium chloride, ruthenium bromide, and ruthenium hydroxide.

These include lupnium acetate and ruthenium carbonyl. These ruthenium compounds can also be used in the form of being supported on a porous carrier such as carbon, silica, alumina, or the like.

As the iodine source, iodine and iodide containing iodine are used. for example.

Examples of iodides include hydrogen iodide, methyl iodide, sodium iodide, potassium iodide, calcium iodide, and lithium iodide. .

What is the amount of catalyst used to suitably carry out the present invention?

1i of cobalt and ruthenium per mole of raw methanol
ID, 1-100 milligram atoms.

Preferably it ranges from 1 to 50 milligram atoms. When the amount is less than this, the rate of one reaction becomes low, and when it is more than this, there is no adverse effect but it is not economical. Excellent catalytic activity can be obtained by combining the two within the above range.

The atomic ratio of ruthenium to cobalt is 0°01-10
, preferably in the range of 0.1 to 2. If the amount is less than this, the production of acetaldehyde and dimethoxyethane will increase.

If the amount is too high, the by-product of methyl formate increases and the selectivity to ethanol decreases.

The amount of iodine used is 0.05 to 20 milligram atoms per milligram atom of cobalt, preferably 0.05 to 20 milligram atoms.
It ranges from 1 to 10 milligram atoms. If it is less than 0.05 milligrams, the 9- reaction rate tends to be low, and if it is more than this, it becomes uneconomical, so the above range is practical.

The reaction temperature is in the range of 100-250°C.

Preferably it is 130-200°C. At temperatures lower than 100°C, the reaction rate is too low to be practical (and at temperatures higher than 250°C, side reactions increase.

The molar ratio of carbon monoxide and hydrogen is 4:1 to 1:4,
Preferably it is in the range of 1:2 to 2:1.

The reaction pressure may be 50 K9/clG or higher, and there is no particular upper limit, but it is practically 100 to 500 Kic.
A range of -/Q is preferred. These gas mixtures contain 5
A gas inert to the reaction, such as Ar.

N2°CO2, CHa, etc. may be mixed, but in this case, the partial pressures of -carbon oxide and hydrogen must correspond to the above pressure range.

According to the present invention, the selectivity to ethanol can be increased, ethanol can be obtained at a sufficient reaction rate, and the catalyst can be easily recovered since no unstable ligands are used. Furthermore, since the presence of some water gives rather favorable results, there is also the advantage that low-grade methanol mixed with water can be used.

This is an industrially advantageous method for producing ethanol.

Note that the method of the present invention can be suitably carried out by either a batch method or a continuous method.

Methanol reaction rate in the following examples and comparative examples,
The ethanol selectivity, the actual methanol conversion rate, and the realizable ethanol selectivity are defined as follows.

Methanol conversion rate (%) Selectivity to each product (%) Actual methanol conversion rate (%) Realizable selectivity to ethanol (%) Note that among the products that can be converted to methanol or ethanol Ingredients include 7cetaldehyde, dimethoxyethane, methyl acetate, and methyl ethyl ether.

Example 1 Methanol 7J/(0.22 mol) was placed in a stainless steel breakage type autoclave with an internal volume of 1110 m/m.

Benzene 12&(0,15 mol), water 2y(0,1
1 mol), cobalt iodide 1.9 (3°2 mmol), and ruthenium chloride trihydrate 0.2'l (0.7
5 mmol) and the container was sealed. Next, a mixed gas of carbon oxide and hydrogen (H2/C0=2) was added to 2401'P/storeG.
and reacted at 170°C for 1 hour. After the reaction, the autoclave was cooled and residual gas was purged, and the two reaction product liquids were analyzed by the internal standard method using a gas chromatograph. As a result, methanol reaction rate 3
At 5.6%, the ethanol selectivity was 66.5%, and the selectivity for each other component was 0.90 for acetaldehyde.
%, methyl ethyl ether 12.1%, methyl acetate
It was 3°87%. At this time, the actual methanol conversion rate was 82.7%, and the selectivity to ethanol that could be achieved was 79.9%.

Examples 2 to 8 The results of changing the reaction temperature, amount of water added, mixed gas composition, amount of catalyst, and type of aromatic hydrocarbon in the presence or absence of water using the same method as in Example 1 were shown. 1st
Shown in the table.

13- Comparative example 1 Internal volume 100II! Methanol 211 (0.66 mol) and cobalt iodide 1# (3.2 mmol) were placed in a stainless steel damping autoclave.

and ruthenium chloride hexahydrate 0,2.1/(0°7
5 mmol) and the container was sealed. Next, a mixed gas of carbon oxide and hydrogen (H2/Co = 2) was added to 240 ηh
The mixture was pressurized into dQ and reacted at 170° C. for 1 hour.

After the reaction, the autoclave was cooled and residual gas was purged, and the reaction product liquid No. 11 was analyzed by an internal standard method using a gas chromatograph. As a result, the ethanol selectivity was 38.5% at a methanol conversion rate of 35.5%, and the selectivity for each other component was 0.
．． 90%, methyl ethyl ether 25.4%, methyl acetate 8.9%, and dimethoxyethane 1.96%. The actual methanol conversion rate at this time was 28.9%, and the selectivity to ethanol that could be achieved was 65.5%.

16- Comparative Examples 2 to 6 Comparative Example 2 in which water was added to Comparative Example 1. and aliphatic hydrocarbons in place of aromatic hydrocarbons. Comparative Examples 6 and 6 using alicyclic hydrocarbons in the presence or absence of water are shown in Table 2.

=171

Claims (1)

[Claims] Production of ethanol, characterized in that aromatic hydrocarbons are present in one reaction system when producing ethanol by reacting methanol, carbon monoxide, and hydrogen in the presence of a catalyst containing cobalt, ruthenium, and iodine as active ingredients. law