JPS59118727A - Production of ethanol - Google Patents

Abstract

PURPOSE:To produce ethanol in high selectivity, suppressing the production of methyl ethyl ether and methyl acetate, by reacting methanol with CO and H2 in the presence of a catalyst containing Co, Ru, I and optionally Fe, adding methyl ethyl ether and methyl acetate to the reaction system. CONSTITUTION:Ethanol is produced by the reaction of methanol with CO and H2 in the presence of a catalyst containing Co, Ru, I and optionally Fe. In the above process, the reaction is carried out in the presence of methyl ethyl ether and methyl acetate. The molar ratio of methyl ethyl ether and methyl acetate to methanol are 0.01-2 and 0.005, respectively. The amount of the catalyst is 1-50mg of Co per 1mol of methanol, and the atomic ratio of Ru to Co is 0.1-2. EFFECT:Since the process does not necessitate unstable ligand, the recovery and reuse of the catalyst can be carried out easily.

Description

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

Conventionally, methods for producing ethanol from methanol, carbon oxide, and hydrogen generally include cobalt as a catalyst and iodine or bromine as active ingredients, and, if necessary, ruthenium, osmium compounds, and various other substances. A method is known in which a ligand or the like is used in combination.

For example, Japanese Patent Publication No. 5B-24865 discloses a method in which methanol, carbon monoxide and hydrogen are reacted in the presence of a cobalt catalyst and an iodine promoter.

Further, US Pat. No. 3,285,948 discloses a method in which methanol, carbon oxide, and hydrogen are reacted in the presence of a soluble cobalt compound, iodine or iodide, and a ruthenium compound catalyst.

In recent years, catalyst systems have been proposed in which various ligands such as 6th phosphine, 6th antimony, and 6th arsine are combined as promoters in addition to the above catalyst systems. For example, JP-A-51
-149213 is a method in which methanol, -carbon oxide, and hydrogen are reacted using a hydrocarbon as a solvent in the presence of a cobalt-halide-tertiary phosphine catalyst.

JP-A-55-49326 discloses a method of reacting in the presence of a catalyst consisting of cobalt-iodine or a polydentate ligand containing a nitrogen or phosphorus atom. British Patent No. 2,036,73
No. 9 is a method in which a catalyst containing cobalt and other group 8 metals is used, and the reaction is carried out in the presence of iodine or bromine as a promoter, as well as 6-phosphine, 6-arsine, or tertiary antimony. It is.

Further, JP-A-55-92330 discloses a hydritocobartocarbonyl complex, iodine, a ruthenium compound, and a tertiary carbonyl complex.
This is a method in which the reaction is carried out in the presence of a catalyst containing phosphine, tertiary antimony, or 6-arsine as an active ingredient. U.S. Pat. No. 4.2!13,466 uses a catalyst system consisting of cobalt, ruthenium, iodine, and tertiary phosphine, P/I (molar ratio) = 1:, 0.36 to 1:5.
, P/Co (molar ratio) = 1, 5 or more.

Moreover, recently, as a method of using a catalyst other than cobalt, a catalyst system in which iron, ruthenium, manganese, or osmium is combined with a nitrogen-containing compound has been proposed. For example, US Pat. No. 4,301,312 discloses a method in which methanol, carbon oxide, and hydrogen are reacted in the presence of a tertiary amine as a nitrogen-containing compound.

However, when we investigated in detail whether the method using the catalyst system represented above could be applied to an industrial ethanol production method, we found that in addition to the target ethanol, methane, dimethyl ether, methyl ethyl ether, diethyl ether A large number of by-products such as , acetaldehyde, dimethoxyethane, acetic acid, methyl acetate, ethyl acetate, and other 02 or higher compounds are generated simultaneously, and the selectivity to ethanol is not sufficient, especially when using ligands together. was found to have various problems as an industrial catalyst.

That is, in Japanese Patent Publication No. 38-24863 or U.S. Patent No. 3,285,948, as mentioned above, in the presence of a catalyst containing cobalt-iodine or cobalt-iodine-ruthenium as an active ingredient, in the absence of a solvent, the reaction temperature is 175-23
0℃, pressure 281 kl/(yr1 or more, methanol,
- A method of reacting carbon oxide and hydrogen. These catalyst systems are easy to handle because they do not use any ligands, but according to the inventors' studies, ethers and methyl acetate are produced in particular by the above-mentioned byproducts, and free It had the drawback of extremely low selectivity to ethanol.

On the other hand, in the method in which the above 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. As a result, the by-product of methane from methanol increases, and many of the above-mentioned by-products are also produced, and the selectivity to ethanol cannot necessarily be said to be high. In particular, these methods use iodine or bromine in addition to cobalt and ruthenium, and multiple tertiary phosphine, tertiary antimony, tertiary arsine, or tertiary amines as ligands, so they are industrially difficult. This causes various problems as follows. In other words, according to the studies conducted by the present inventors, ligands such as tertiary 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. Furthermore, even if a method were adopted in which each catalyst component was recovered, the catalyst system would be complicated, requiring complicated steps, and the loss associated with recovery would be large.
Since it is expensive, it has the disadvantage of increasing catalyst costs.

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

Previously, the present inventors proposed a method for producing ethanol in which methanol, carbon oxide, and hydrogen were mixed in the presence of a solvent and water in the presence of a catalyst containing cobalt, iron, ruthenium, and iodine as active ingredients. We proposed a method to react (
Patent application No. 57-102145). Although this method has the advantage that the catalyst can be easily recovered and reused in that it does not use unstable ligands, it still has the disadvantage that methyl ethyl ether and methyl acetate are produced as by-products.

In order to eliminate these drawbacks, the present inventors have developed a sharp fiJl[
As a result, when producing ethanol by reacting methanol, carbon oxide and hydrogen in the presence of cobalt, ruthenium and iodine or a catalyst containing cobalt, ruthenium, iron and iodine as active ingredients, methyl is present in the reaction system. It was discovered that by adding ethyl ether and methyl acetate, the by-products of both were suppressed and the selectivity to ethanol was greatly improved, and the present invention was completed.

That is, the present invention is directed to the production of process 1) by reacting methanol, carbon oxide and hydrogen in the presence of cobalt, ruthenium and iodine or a catalyst containing cobalt, ruthenium, iron and iodine as active ingredients. , a method in which both methyl ethyl ether and methyl acetate are added.

The amount of methyl ethyl ether and methyl acetate added in the present invention depends on the presence or absence of a solvent, the type of solvent, the presence or absence of water addition,
Although it varies depending on the reaction conditions and cannot be uniformly defined, depending on the conditions, there is an amount added at which by-products of methyl ethyl ether and methyl acetate are completely suppressed. Generally, the amount of methyl ethyl ether added to methanol is in the range of 0.01 to 2 molar ratio, and the amount of methyl acetate is in the range of 0.005 to 1 molar ratio.

The catalyst used in the invention is a catalyst system containing cobalt, ruthenium and iodine or cobalt, ruthenium, iron and iodine as active ingredients. Sources of cobalt, iron, and ruthenium include metallic cobalt, metallic iron, metallic ruthenium, and five types of compounds thereof. Cobalt compounds include cobalt iodide, cobalt bromide, cobalt chloride, cobalt oxide, cobalt carbonate, and formic acid. Cobalt, cobalt acetate, Nanzu/fJ-71ζruto, :! These include Aρ-acetyl 7cetonate and cobalt carbonyl compounds.

Examples of iron compounds include iron iodide, iron chloride, iron oxide, iron acetate, iron acetylacetonate, iron carbonyl, and the like.

In addition, ruthenium compounds include ruthenium iodide,
Ruthenium chloride, Ruthenium bromide, Ruthenium hydroxide,
Ruthenium acetate, ruthenium carbonylnato Iodine sources include iodine and iodide, and examples of iodide include hydrogen iodide, sodium iodide, potassium iodide, calcium iodide, and lithium iodide. Industrially, cobalt iodide, iron iodide, and ruthenium chloride or ruthenium iodide are preferably used as catalyst sources from the viewpoint of ease of handling.

The amount of catalyst used for suitably carrying out the present invention is in the range of from 1 to 500 atoms, preferably from 1 to 5019 atoms, per mole of methanol starting material. When the amount is less than this, the reaction rate becomes low, and when it is more than this, it is not economical although there is no adverse effect, and the above range is practical.

The atomic ratio of ruthenium to cobalt is 0.

01-4, preferably in the range 0.1-2.

If it is less than this, the production of 7cetaldehyde and dimethoxyethane will increase, and if it is more than this, by-products such as dimethyl ether and methyl formate will increase, and the selectivity to ethanol will decrease.

In the present invention, it is preferred to use a solvent. Aromatic hydrocarbons and cyclic ethers are particularly suitable as solvents. Aromatic hydrocarbons include benzene, toluene, xylene, ethylbenzene, trimethylbenzene,
Examples include methylethylbenzene, diethylbenzene, isopropylbenzene, and the like. Further, the cyclic ether is a compound represented by the general formula (R-0)n, and tetrahydrofuran, 1,6-dioxane, and 1,4-dioxane are preferable. The amount of solvent used is usually 0 for 1 volume of methanol.
．． 05-2.

volume, preferably in the range of 0.1 to 10 volume.

The present invention can also be carried out by adding water to the reaction system. The amount of water that can be added is in the range of 2 moles or less per mole of methanol. If more than this is added, the reaction rate tends to decrease.

The reaction temperature is in the range of 100 to 25°C, preferably 130 to 200°C. At temperatures below 100°C, the reaction rate decreases, and at temperatures above 250°C, side reactions increase.

The reaction pressure should be 30 kl/cm'G or more,
There is no particular upper limit, but practically 100 to 50 tons
A range of l'il/cm'G is preferred. - The molar ratio of carbon oxide to hydrogen is between 4.1 and 1.4, preferably between 2:1 and 1.2. These mixed gases (synthesis gas) contain gases that are inert to the reaction, such as argon,
Nitrogen, carbon dioxide, methane, 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 method of the present invention, the production of methyl ethyl ether and methyl acetate, which are the main by-products, can be completely suppressed, and ethanol can be obtained with high selectivity under relatively mild reaction conditions. Therefore, from an industrial perspective, it means a method in which methyl ethyl ether and methyl acetate can be recycled to the raw material system. Moreover, since no unstable ligands are used, the catalyst can be easily recovered and reused. It also has the advantage of being able to use low-grade methanol mixed with water, making it an industrially advantageous method for producing ethanol.

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

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

Realizable ethanol C96 with a methanol conversion rate Q and a substantial methanol conversion rate of 0) Among the products, components that can be converted into methanol or ethanol include acetaldehyde, dimethoxyethane, diethyl ether, ethyl acetate, and the like.

Example 1 7 g (0,2185 mol) of methanol and 1 mol of benzene were placed in a stainless steel shaking autoclave with an internal volume of 100 m7.
2g ([1,154 mol), water 2g (0,141 mol)
, 4.6 g (0,077 mol) of methyl ethyl ether,
and 0.8 g (0, C111 mol) of methyl acetate, 0.5 g (j, 6 mmol) of cobalt iodide as a catalyst, 0.25 g (0,81 mmol) of iron iodide, and 0.0 g of ruthenium chloride hexahydrate. .2 g (0, fromimole) was charged and the container was sealed.

Next, a mixed force of carbon oxide and hydrogen (H2/C0 = 2 molar ratio) was press-fitted into 24.0k117cm"G, and 15
The reaction was allowed to proceed for 3 hours at 0°C. After the reaction, the autoclave was cooled and residual gas was purged, and the reaction product liquid was analyzed using a gas chromatograph. As a result, the ethanol selectivity was 86.1% at a methanol reaction rate of 30.4L96IC, and the selectivity to other components was as follows: dimethyl ether i, 8296, acetaldehyde 0
．． 32%, methyl formate 0.12%, diethyl ether 0
．． 6196, acetic acid 1.62%, and ethyl acetate 6.21%, and there were no by-products of methyl ethyl ether and methyl acetate. The actual methanol conversion rate at this time was 29.8
%, and the achievable ethanol selectivity is 90.596
Met.

Examples 2 to 4 Table 1 shows the experimental results in which methyl ethyl ether and methyl acetate were added in the same manner as in Example 1, and the charging conditions, reaction conditions, solvent type, etc. were varied.

Comparative Example 1 (corresponding to Example 1) 7 g of methanol (0.2 + 85 mol) and benzene + 2 were placed in a stainless steel shaking autoclave with contents: bond + ooi.
g (0,154 mol), water 2 g (0,111 mol),
Cobalt iodide 0.5 g (+, 6 mmol), iron iodide 0. ．． 25 g (0.81 mol) and 0.2 g (0.76!j mol) of ruthenium chloride hexahydrate were charged and the flask was sealed. Next, a mixed gas of 1-carbon oxide and hydrogen (H2
/C0=2 molar ratio) was press-fitted into 240 kg/(G),
The reaction was carried out at 150°C for 6 hours. As a result, the ethanol selectivity was 7 at a methanol conversion rate of 26.8%.
The selectivity to other components is 2.44% dimethyl ether, 0.27% acetaldehyde, 0.07% methyl formate, and 3.6196% ethyl methyl ether.
, diethyl ether 0.5496, methyl acetate 4.88
96%, acetic acid 0.6096%, and ethyl acetate 0.82%. The actual methanol conversion rate at this time was 25.096, and the achievable ethanol selectivity was 84.396. .

Comparative Examples 2 to 4 The results of Comparative Examples 2 to 4 without the addition of methyl ethyl ether and methyl acetate to Examples 2 to 4 are shown in the second table.
Shown in the table.

Claims (1)

[Claims] When producing ethanol by reacting methanol, carbon oxide and hydrogen in the presence of cobalt, ruthenium and iodine or a catalyst containing cobalt, ruthenium, iron and iodine as active ingredients, both methyl ethyl ether and methyl acetate are added. A method for producing ethanol characterized by