JPS61218540A - Production of ethanol - Google Patents

Abstract

PURPOSE:In producing the titled substance by reacting carbon monoxide with hydrogen in a liquid medium containing a catalyst comprising ruthenium, etc. as a main component, to improve a yield without requiring separation process, by synthesizing the titled substance while circulating the raw material gas through the medium, entraining it in the fed synthesis gas and taking it out. CONSTITUTION:A synthesis gas containing carbon monoxide and hydrogen is fed from the conduit 6 to the reactor 1 having a liquid medium containing a ruthenium and a halogen compound. The reactor 1 is kept at 180-260 deg.C at 300-600kg/cm<2> reaction pressure, the fed synthesis gas is brought into contact with the catalyst to give ethanol. The reaction product is entrained in the synthesis gas which is flowing in an unreacted state in the liquid medium, sent through the conduit 7 to the cooler 2, separated into a noncondensing gas and a condensed solution by the high-pressure vapor-liquid separator 3, and a liquid phase containing ethanol is taken out through the conduit 9.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for directly synthesizing ethanol from -carbon oxide and hydrogen (hereinafter referred to as 1 synthesis gas). More specifically, the present invention relates to an improved method for directly synthesizing ethanol from one synthesis gas by a liquid phase homogeneous catalytic reaction using ruthenium compounds and halogen compounds as catalysts.

Ethanol is a compound that has a wide range of uses as an intermediate raw material or solvent for various chemicals.

(Prior Art and Problems to be Solved by the Invention) Many methods have been proposed for directly producing ethanol from synthesis gas using a ruthenium liquid-phase homogeneous catalyst.

A method for directly producing these carboxylate derivatives (Japanese Unexamined Patent Publication No. 115834/1989), and a method for selecting methanol and ethanol by contacting a homogeneous ruthenium catalyst, a halogen or a halogenation promoter, and an organic oxidized phosphine compound with synthesis gas. method of manufacturing (Unexamined Japanese Patent Publication No. 5
No. 7-82327).

Technology for producing ethanol directly from synthesis gas.

To date, it has not yet been industrialized. In order to implement this technology industrially, a continuous production process is necessarily required, in which ethanol is synthesized by bringing synthesis gas into contact with a catalyst liquid, and then ethanol is separated from the catalyst liquid.

Unfortunately, to date, the development efforts for producing ethanol by liquid-phase homogeneous catalysis using ruthenium have been focused on improving the performance of the catalyst, including the economical separation of the product and the catalyst liquid. The technology is little known.

Synthesize ethanol from syngas and then.

In the continuous production process of separating ethanol from the catalyst liquid, the catalyst liquid and synthesis gas are usually fed into a reactor and reacted, and after the catalyst liquid containing the product is taken out from reactor 1, the product is separated. A process consisting of separating into a catalyst liquid and a catalyst liquid is known.

Such methods include, for example, a method for producing ethylene glyco-A/1 methanol and ethanol using a ruthenium catalyst (Japanese Unexamined Patent Publication No. 57-130936), a method for producing ethylene glycol A/1 methanol and ethanol using a ruthenium catalyst, %
Repeatedly remove methanol, before exceeding the liquid phase.
A method for continuously producing ethylene glycol and ethanol (Japanese Unexamined Patent Publication No. 82328/1982) is disclosed.

However, these methods: 1. A separate process (equipment) is required to separate the low concentration products from the catalyst liquid. Furthermore, according to experiments conducted by the present inventors, when a ruthenium liquid-phase homogeneous catalyst is used, the resulting alcohol accumulates in the catalyst liquid, reducing the catalyst performance. This fact is based on the above-mentioned Japanese Unexamined Patent Publication No. 57
-82328, ``During the reaction process, in the liquid phase,
Experiments have shown that as the concentration of ethylene glycol increases, the rate of ethylene glycol production decreases correspondingly.'' For these reasons, in order to separate the product from the catalyst and liquid, it is economically preferable to have a high product concentration in the catalyst liquid. must be suppressed and controlled as much as possible.

However, it is questionable whether the active species generated under the reaction conditions of high temperature and high pressure will remain stable even after being handled under separation conditions and separation conditions.

The object of the present invention is to take into account the above-mentioned problems of the prior art and to provide an economical method for continuously producing ethanol from synthesis gas.

(Means for Solving the Problems) The present inventors have conducted extensive studies to solve these problems. As a result, I discovered that ethanol could be obtained by supplying synthesis gas to the catalyst liquid held in the reactor to produce ethanol, and stripping the produced ethanol with unreacted synthesis gas to obtain ethanol. Completed the invention.

Namely, the present invention provides a method for producing ethanol by contacting a catalyst-containing liquid medium containing a ruthenium compound and a halogen compound as main components with a synthesis gas containing -carbon oxide and hydrogen under high temperature and high pressure. The method is characterized in that synthesis gas is continuously supplied to a catalyst-containing liquid medium held in one reactor to produce ethanol-1:2, and the produced ethanol is taken out along with unreacted synthesis gas. This is a method for producing ethanol.

Any ruthenium compound used in the present invention can be used as long as it forms a ruthenium complex having a carbon monoxide ligand under one reaction condition. Examples of these include, in addition to ruthenium metal, ruthenium oxides such as ruthenium dioxide and ruthenium tetroxide;
These hydrates, ruthenium chloride, ruthenium iodide,
These include mineral salts of ruthenium such as ruthenium nitrate, and organic salts of ruthenium such as ruthenium acetate and ruthenium propionate.

Ruthenium compounds can also be used directly in the form of coordination compounds, examples of which include ruthenium carbonyl, such as tolyltenicumdodecacarbonyl, and ruthenium combined with oxygen, sulfur, halogen [ 1! J-n,
Arsenic, antimony.

Examples include ruthenium complexes coordinated with ligands such as bismuth, and their salts.

Among these ruthenium compounds, ruthenium, ruthenium oxide, ruthenium halide, ruthenium, or one of the ruthenium compounds as a promoter in the method of the present invention,
It is necessary to use halogen compounds. In the absence of these halogen compounds, ethanol activity and selectivity are significantly lower.

These halogen compounds include metal salts such as alkali metal salts and alkaline earth metal salts having halogen ions such as chloride ions, bromide ions, and iodine ions as anions constituting the salts.

Examples include salts such as ammonium salts, quaternary phosphonium salts, and iminium salts, and hydrocarbon halides such as alkyl halides and aryl halides. Ma?
t+, /S Hydrogen halides, acid halogenides, transition metal halides, and the like can also be used. More specifically, (1) Examples of metal salts include lithium chloride, lithium pentabromide, sodium chloride, potassium bromide, ceniodide, cum, magnesium chloride, and lanthanum iodide.

, J. 7-.

Id, trimethylammonium iodide, dimethylethylammonium chloride, methyl 1'.

■Examples of quaternary phosphonium salts include, for example, ethyl ammonium iodide, tetramethylammonium chloride, tetramethylammonium iodide, tetraphenylammonium chloride, and cetyltriethylammonium bromide. butylphosphonium bromide, n-heptyltriphenylphosphonium bromide, benzyltriphenylphosphonium iodide, methyltriphenylphosphonium chloride, etc.

■ Examples of iminium salts include bis(triphenylphosphine)iminium bromide, bis(triphenylphosphine)iminium bromide, his(triphenylphosphine)iminium iodide, and at least a portion of the phenyl group of these iminium compounds. Examples of alkyl halides include iminium salts in which is substituted with a methyl group or ethyl group, etc., methyl chloride, methylene chloride - chloro'.

Rumu Wataru, Carbon tetrachloride, Methyl iodide, Echiku iodide,
l; Engineered hensyl chloride, benzylnato iodide, ■halo U'
? f' Examples of hydrogen tetrahydride include hydrogen chloride, hydrogen bromide, and so on.

These halogen compounds can be used alone or in combination of two or more.

In the method of the present invention, the amount of these halogen compounds used is per gram atom of ruthenium.

Halogen atoms range from 0.1 to 200 gram atoms.

More preferably, it is in the range of 1 to 20 gram atoms.

The method of the invention is carried out in a liquid medium. The liquid medium used is preferably an aprotic liquid solvent. In protic liquid media such as water and alcohol, the ethanol production activity is low and the selectivity is also poor.

In the method of the present invention, the aprotic liquid solvent preferably used is, for example, heptane.

Hydrocarbons and aromatic hydrocarbons such as octane, cyclohexane, decalin, tetralin, kerosene, benzene, toluene, xylene, hexamethylbenzene, chloropentane, 0-di(t5゛tetrahydrofuran, ethyl ether) , Aniso-jj
:□ ′〃, ethers such as phenyl ether, diglyme, tetraglyme, 18-crown-6, methyl acetate,
Esters such as ethyl butyrate, methyl benzoate, and γ-butyrolactone, ketones such as acetone, acetophenone, and benzophenone, N-methylpyrrolidin-2-one, N-ethylpyrrolidin-2-one, N,N-dimethylacetamide, N-substituted amides such as N-methylpiperidone, hexamethylphosphoric triamide, N.

N-diethylaniline, N-methylmorpholine.

Tertiary amines such as pyridine and quinoline, sulfones such as sulfolane, sulfoxides such as dimethyl sulfoxide, and urea derivatives such as 1,3-dimethyl-2-imidazolidinone.

Examples include phosphine oxides such as tributylphosphine oxide and silicone oil.

1''; near-thyl compounds and phosphine oxytes are listed.

A liquid solvent having a boiling point of 200° C. or higher is more preferred. However, even if the boiling point is less than 200°C, it can be separated from the product and recycled to the reactor for use.

These liquid solvents can be used alone or in combination of two or more.

Furthermore, the liquid solvent used in the method of the present invention can be used even if it is solid at room temperature and pressure, as long as it is liquid at least under the reaction conditions.

The method of the present invention has a reaction temperature in the range of 160 to 300°C,
Preferably it is in the range of 180 to 260°C.

When the reaction temperature is less than 160°C, the reaction between -carbon oxide and hydrogen is extremely slow. Also, if the degree of one reaction exceeds 300℃,
Methane by-product increases significantly and ethanol selectivity decreases.

In addition, 1 reaction pressure is in the range of 150 to 800 kP/i, preferably ξ
°Although the practical pressure is less than 5ooky/d-
The unreacted synthesis gas that is taken out along with the produced ethanol is supplied to one reactor, and is mainly the remaining gas consumed in the production of ethanol, with a small amount of by-product of course. contains carbon dioxide and methane.This gas strips out the ethanol produced at the same time.

The supplied gas may be mixed with a gas inert to the reaction.

By mixing an inert gas in this way, the stripping effect of ethanol can be improved.

As such a gas, an inert gas such as nitrogen, argon, helium, etc. is used.

The gas hourly space velocity range of the gas supplied to the reactor is not particularly limited. The optimum gas hourly space velocity is determined by the type 1 reaction source of the reactor, reaction pressure, catalyst performance, etc.

If the space velocity is too high or too low, the visibility of the entrained product will be reduced and the stripping efficiency will be reduced.

The method of the present invention will be specifically explained with reference to the drawings.

FIG. 1 is a manufacturing process diagram for carrying out the method of the present invention.

In FIG. 1, one reactor (1) holds a liquid medium containing a ruthenium compound and a halogen compound. Synthesis gas is fed to one reactor (1) through conduit (6). Reactor (1) has a reaction temperature of 180°C and 260°C.
and the reaction pressure is in the range of 300 to 600 kg/cril.

Synthesis gas continuously fed into such a reactor (1) contacts a catalyst in a liquid medium to produce ethanol.

The produced ethanol and co-produced by-products are entrained in the liquid medium by the unreacted syngas flowing through the conduit (
7) and is led to the cooler (2).

Here the ethanol and by-products are cooled and removed through the high and low pressure valve (5).

(Function) According to the present invention, ethanol is produced while flowing raw material synthesis gas through a liquid medium containing a catalyst.

The generated ethanol is taken out along with the supplied synthesis gas.

According to this method, the process of separating the product and the catalyst liquid can be omitted, and a highly concentrated product can be directly recovered from the reactor. In addition, the catalyst liquid does not need to be taken out of the reactor to separate it from the products (it is always retained within the reactor, so the catalyst liquid is kept under optimal conditions for synthesizing the desired product). In other words,
The catalyst regeneration process associated with separation of catalyst liquid and product can be omitted.

In addition, the products in the reactor are always accompanied by gases containing unreacted gases, and are taken out of the reactor. ■ - There is no need for a separation process (equipment) between the catalyst liquid and the products. It has the following characteristics: there is no need to increase the concentration of the product for separation, and there is no risk of partial activation of the catalytically active species under these separation conditions.

Ethanol is produced directly from synthesis gas.

In other words, the method of the present invention improves C1 chemical technology to an industrial level compared to conventionally proposed methods.

(Example) Hereinafter, the method of the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example 1 21 mmole of triruthenium/'
(Ru3(Co)12), 35 mmole of bis(triphenylphosphine)iminium promyl-
(Ph3P)2+ - NB'), 84 mmole of glue C4 and liquid solvent, 2807 tri-n-butylphosphine oxide was introduced from the top of the tubular reactor, and after the reactor was closed, synthesis gas was introduced from the bottom of the reactor. The administration of ``M'' was started little by little.

The temperature of the reactor reached 240℃ □゛-1 The liquid was collected.

The results of analyzing the liquid using a gas chromatograph.

11.5% as methanol, 68% as ethanol
．． 6%, 10.5% as propatool, 2.7% as formic acid, 4.3% as acetic acid, and 1.3% as acetaldehyde. (This is the weight percentage calculated and added).

Examples 2-9 By the same method as in Example 1... rogen compound.

The reaction was carried out by changing the additives, liquid solvent 1 reaction density, and space velocity as shown in Table 1.

These results are shown in Table 1 together with Example 1.

Comparative Example 1 14 mmole of ruthenium acetylacetoner) (Ru(acac)3), 85 mmole per hour
Synthesis gas (gas space velocity 15007
time). As a result of increasing the temperature while maintaining the pressure at 400 kg/d, a steady value was obtained about 2 hours after the reaction temperature reached 220°C.

At this time, 438 g of liquid was collected from the reactor outlet per hour. As a result of analyzing the liquid in the same manner as in the example, it was 1.8% as methanol and 2.0% as ethanol.
%, 0.2% as a property tool.

The amounts were 0.1% as formic acid, 0.2% as acetic acid, and 0.2% as acetaldehyde (these indications are the same as in Example 1).

Comparative example 2 A halogen compound was prepared in the same manner as in Comparative Example 1.

The reaction was carried out by changing the composition ratio of the additives as shown in Table 1.

The results were summarized in Examples 1 to 9. It is shown in Table 1 together with Comparative Example 1.

Note in Table 1: 1) In Examples 1 to 5 and Comparative Examples 1 to 2, the diameter is 1.
A tubular reactor of 5 cIrL and 120 crIL length (inner volume 200 m/ ) was used. In Examples 6 to 9, the diameter is 3.
crrL length 180 crrL tubular reactor (inner volume 1
200 mj) was used.

Note 2) Methanol, ethanol, and propatool in the table are the values obtained by converting the produced esters and ethers into the corresponding alcohols and adding them.

Note-3) The amount of catalyst in Comparative Examples 1 and 2 is the amount supplied to the reactor per hour.

Note-4) In Table 1, each symbol represents the following compound.

Ru3(CO)t2: triruthenium dodecacarboxylic Ru(acac)3: ruthenium acetylacetonate PPNCl: bis(triphenylphosphine)iminium chloride PPNBr: bis(triphenylphosphine)iminium bromide PPNI: bis(triphenyl) phosphine) iminium iodide LiC1: lithium chloride NMe3I (Br: t') methylammonium bromide NMe3HI: ) limethylammonium iodide Me3PO4: ) limethylphosphoric acid) (3PO4 diphosphoric acid Bu3PO: tri-n-butylphosphine oxide ph2o nidiphenyl ether NMP
:N-Methylpyrrolidin-2-one (Effect) In Comparative Examples 1 and 2, the ethanol concentrations in the recovered liquids were both 3% or less.

Furthermore, in the method of the comparative example, from the first recovered liquid.

A process (equipment) is required to separate the product and catalyst liquid.

On the other hand, in Examples 1 to 9, the ethanol concentration in the recovered liquid was 43 parts or more, and in Example 2, it was 71 parts.

As described above, by using the method of the present invention, it is possible to recover highly concentrated ethanol from one recovered liquid without requiring a step (equipment) for separating the product and the catalyst liquid.

[Brief explanation of drawings]

Figure 1 shows one of the manufacturing flow sheets for carrying out the method of the present invention.
This is an example. In the figure, each symbol is as follows. 1 Reactor, 2 Cooler 23 High pressure gas-liquid separator. 4.5 Pressure reducing valve

Claims (1)

[Claims] 1) In a method for producing ethanol by contacting a catalyst-containing liquid medium containing a ruthenium compound and a halogen compound with a synthesis gas containing carbon monoxide and hydrogen under high temperature and high pressure, the liquid medium is held in a reactor. A method for producing ethanol, which comprises continuously supplying synthesis gas to a catalyst-containing liquid medium to produce ethanol, and removing the produced ethanol along with unreacted synthesis gas.