JPS6033812B2 - Ethanol manufacturing method - Google Patents

Description

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

Conventionally, the method for producing ethanol from methanol, carbon monoxide, and hydrogen chloride uses cobalt and iodine as a catalyst. Contains bromine as an active ingredient,
In addition, ruthenium, osmium compounds,
There are known methods of using various ligands, etc.
Ru.

For example, Japanese Patent Publication No. 38-24863 describes 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 is a method of reacting methanol, carbon monoxide, and hydrogen 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, in addition to the above catalyst systems, various ligands such as tertiary phosphine, tertiary antimony, and tertiary arsine are roughly combined as promoters.

For example, Hakama Kaisho 51-149213 is a method in which methanol, carbon monoxide, and hydrogen are reacted using a hydrocarbon as a solvent in the presence of a cobalt halide-tertiary phosphine catalyst soot. Tokukan Sho 55-4 26 is a method of reacting in the presence of a catalyst consisting of cobalt chloride or a polydentate ligand containing a nitrogen or phosphorus atom. British Patent No. 2,036,739 uses a catalyst consisting of cobalt and other Group 8 metals, and 'P' also contains iodine or bromine as a reagent, as well as tertiary phosphine, tertiary arsine, or tertiary arsine.
This method involves reacting in the presence of antimony. Furthermore, Hakamaseki Sho 55-92330 discloses a method of reacting in the presence of a catalyst containing a hydridocobalt carbonyl compound, iodine, a ruthenium compound, and a tertiary phosphine, tertiary antimony to tertiary arsine, or tertiary arsine as active ingredients.

U.S. Pat. No. 4,233,466 uses a catalyst system consisting of cobalt, ruthenium, iodine, and tertiary phosphine, P/1 (molar ratio) = 1:0.36 to 1:5, P/C
This is a method in which the reaction is carried out under conditions of o (molar ratio) = 1.5 or more. Recently, as a method for using a catalyst other than cobalt, a catalyst system in which a nitrogen-containing compound is combined with iron, ruthenium, manganese, or osmium has been proposed.
For example, US Pat. No. 4,301,312 discloses a method in which ethanol, carbon monoxide, 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, etc. , acetaldehyde, dimethoxychetane, acetic acid, methyl acetate, ethyl acetate, and other C2 or higher compounds are produced simultaneously, and the selectivity to ethyl/ethyl is not sufficient, especially for ligands. It has been found that when used together, there are various problems as an industrial catalyst.

i.e. Samurai Kosho-24863 or U.S. Patent No. 3
No. 285948, as mentioned above, cobalt iodine,
Or, in the presence of a catalyst containing cobalt and ruthenium as active ingredients, in the absence of a solvent, at a reaction temperature of 175 to 230 qo.
, a method in which methanol, carbon monoxide, and hydrogen are reacted at a pressure of 281[9/water or higher].

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 particularly frequently among the created products submitted by the present inventors.
The drawback was that the selectivity to free ethanol was extremely low.
On the other hand, the method in which the above-mentioned catalyst and various ligands are combined roughly suppresses the by-product of ethers, but the addition of the ligand reduces the catalytic activity, so the reaction temperature has to be increased. As a result, the creation of methane from methanol increases,
Many of the above-mentioned by-products are also produced, and the selectivity to ethanol cannot necessarily be said to be high.

In particular, in these methods, in addition to cobalt and ruthenium, iodine or bromine, and tertiary phosphine,
Since a plurality of tertiary antimony, tertiary arsine, tertiary amines, etc. are used, various problems occur industrially 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 is adopted in which each catalyst component is recovered, the catalyst system is complex, requiring a complicated process, and the loss associated with recovery is large, resulting in high 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, as a method for producing ethanol, the present inventors reacted methanol, carbon monoxide, and hydrogen in the presence of a solvent and water in the presence of a catalyst containing cobalt, iron, ruthenium, and iodine as active ingredients. proposed a method (Request 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.
As a result of intensive research to eliminate these drawbacks, the present inventors have discovered that methanol, monoxide and When producing ethanol by reacting carbon and hydrogen, by adding methylethylenal and methyl acetate to the reaction system, the creation of both is suppressed and the selectivity to ethanol is improved. The present invention was completed.

That is, the present invention involves reacting methanol, carbon monoxide, and hydrogen in the presence of a catalyst containing cobalt, ruthenium, and iodine, or cobalt, ruthenium, iron, and iodine as active ingredients to produce ethanol. This method involves adding both methyl and methyl. The amount of methyl ethyl ether and methyl acetate added in the present invention varies depending on the presence or absence of a solvent, the type of solvent, the presence or absence of water addition, reaction conditions, etc., and cannot be uniformly specified. There is an amount added at which the creation of methyl acetate is 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.

Cobalt, iron, and ruthenium sources include metallic cobalt, metallic iron, metallic ruthenium, and various compounds thereof. Cobalt compounds include cobalt iodide,
These include cobalt bromide, cobalt chloride, cobalt oxide, cobalt carbonate, cobalt formate, cobalt acetate, cobalt naphthenate, cobalt acetylacetonate, and cobalt carbonyl compounds. Examples of iron compounds include iron iodide, iron chloride, iron oxide, iron acetate, iron acetylacetonate, iron carbonyl, and the like. Examples of the ruthenium compound include ruthenium iodide, ruthenium chloride, ruthenium bromide, ruthenium hydroxide, ruthenium acetate, and ruthenium carbonyl. 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. In order to suitably carry out the present invention, the amount of cobalt added to the catalyst is as follows:
It ranges from 0.1 to 500 female atoms, preferably from 1 to 50 female atoms per mole.

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 between 0.01 and 4, preferably between 0.1 and 2.

If it is less than this, the production of acetaldehyde and dimethoxychetane will increase, and if it is more than this, the creation of dimethyl ether, methyl formate, etc. 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. Examples of aromatic hydrocarbons include benzene, toluene, xylene, ethylbenzene, trimethylbenzene, methylethylbenzene, jetylbenzene, isopropylbenzene, and the like. Further, the cyclic ether is a compound represented by the general formula (R-○)n, and tetrahydrofuran, 1,3-dioxane, and 1,4-dioxane are preferable. The amount of solvent used is usually 0.05 to 20 methanol per methanol, preferably 0.1 to 1 methanol. 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 ranges from 100 to 250 qo, preferably from 130 to 200 qo.

At temperatures lower than 100°C, the reaction rate decreases, and 25
At temperatures higher than 000, side reactions increase.

The reaction pressure only needs to be 30k9/mG or more, and there is no particular upper limit on the upper limit, but practically it is 100 to 500k9/mG.
A range of is suitable.

The molar ratio of carbon monoxide to hydrogen is between 4:1 and 1:4, preferably between 2:1 and 1:2. These mixed gases (synthesis gas) may contain gases that are inert to the reaction, such as argon, nitrogen, carbon dioxide, methane, etc., but in this case, the partial pressure of carbon monoxide 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 creation 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. Furthermore, 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.

Methanol reaction rate (%) Q Yamakomi methanol (one reacted methanol), mole of methanol charged, mole Mol XIOO
Actual methanol reaction rate (%) = (Prepared methanol -
unreacted methanol - converted methanol), mol XIOO
Preparation methanol, Mol W Himari ethanol + converted ethanol),
Mole Realizable ethanol (%) = (Prepared methanol monofluoric reaction methanol - converted methanol), moles x 100 In addition, among the products, components that can be converted to methanol or ethanol include acetaldehyde, dimethoxychetane, diethyl ether, ethyl acetate, etc. There is.

Example 1 In a stainless steel shaking autoclave with an internal volume of 100, 7 methanol (0.2185 mol) and 1 mol of benzene were added.
2 evenings (0.154 mol), 5 evenings of water (0.111 mol),
Methyl ethyl ether 4.6 mmol (0.077 mol), methyl acetate 0.8 mmol (0.011 mol), cobalt iodide 0.5 mmol (1.6 mmol) as catalyst, iron iodide 0 0.25 mmol (0.81 mmol) and 0.2 mmole (0.76 mmol) of ruthenium chloride trihydrate were charged and sealed.

Next, a mixed gas of carbon monoxide and hydrogen (molar ratio of 2/CO=2) was injected into 240 k9/g and reacted at 150 kC for 3 hours. 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 conversion rate of 30.4%.
%, and the selectivity to each other component is dimethyl ether 1.82%, acetaldehyde 0.32%, methyl formate 0.12%, diethyl ether 0.61%, acetic acid 1.
62%, ethyl acetate 3.21%, and no methyl ethyl ether or methyl acetate was created. The actual methanol conversion rate at this time was 29.8%, and the achievable ethanol selectivity was 90.5%. Example 2~
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.

Table 1 Comparative Example 1 (corresponding to Example 1) In a stainless steel shaking autoclave with an internal volume of 100, 7 methanol (0.2185 mol) and 1 mol of benzene were added.
2 evenings (0.154 mol), 2 evenings of water (0.111 mol),
0.5 mmol of cobalt iodide (1.6 mmol), 0.25 mmol of iron iodide (0.81 mol), and ruthenium chloride.
0.2 mmol (0.76 mmol) of trihydrate was charged and the mixture was sealed.

Next, a mixed gas of carbon monoxide and hydrogen (molar ratio of 2/CO=2) was injected into 240k9/G, and reacted for 3 hours at 0:00. As a result, the methanol reaction rate was 26
．． At 8%, the ethanol selectivity was 75.6%,
Selectivity to other components is dimethyl ether 2.44%
, fucetaldehyde 0.27%, methyl formate 0.07%
, ethyl methyl ether 3.61%, diethyl ether 0.54%, methyl acetate 4. The total percentage was 0.60% acetic acid and 0.82% methyl acetate. The actual methanol conversion rate at this time was 25.0%, and the achievable ethanol selectivity was 84.3%. 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.

Table 2

Claims (1)

[Claims] 1 methanol, carbon monoxide and hydrogen, cobalt,
A method for producing ethanol, which comprises adding both methyl ethyl ether and methyl acetate when producing ethanol by reacting in the presence of a catalyst containing ruthenium and iodine or cobalt, ruthenium, iron and iodine as active ingredients.