JPS63154634A - Production of ethanol - Google Patents

Abstract

PURPOSE:To economically suppress corrosion of a reactor in directly synthesizing ethanol from a synthesis gas by using a specific catalyst containing a corrosive component, by using a reactor comprising stainless steel of austenite type containing molybdenum as a material. CONSTITUTION:In producing an oxygen-containing compound such as methanol, ethanol, etc., by bringing carbon monoxide and hydrogen into contact with a liquid medium containing a ruthenium compound, a cobalt compound and a halogen compound under high-temperature and high-pressure conditions at 180-260 deg.C under 300-500kg/cm<2>G, a reactor having a material stainless steel of austenite type containing molybdenum is used. Corrosion of a reactor in the presence of a highly corrosive catalyst and under corrosive reaction conditions is suppressed by using the reactor of an inexpensive material without using a reactor of an expensive material such as hastelloy C, titanium, etc., and cost of the reactor is extremely reduced to give ethanol advantageously.

Description

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

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) There are many methods (proposed) for directly synthesizing ethanol from synthesis gas using liquid phase homogeneous catalysts of ruthenium compounds. For example, solubilized ruthenium carbonyl A method for directly producing methanol, ethylene glycol and ethanol or their carboxylate derivatives by reacting synthesis gas in an appropriate solvent containing a complex (Japanese Unexamined Patent Publication No. 55-1
No. 15834).

Other examples include a method of selectively producing methanol and ethanol by bringing a homogeneous ruthenium catalyst, a halogen or a halogenation promoter, and an organic oxidized phosphine compound into contact with synthesis gas (Japanese Unexamined Patent Publication No. 57-82327).

However, most of these known techniques are aimed solely at improving the reaction performance, and nothing is known about the equipment, especially the material of the reactor.

To produce ethanol from synthesis gas, carbon monoxide is needed as a raw material, and halogen compounds and metal carbonyl compounds are essential as catalysts, but these are extremely corrosive under the high temperature and high pressure conditions that are the reaction conditions. . Therefore, in general-purpose reactors such as stainless steel, the material of the reactor corrodes, causing corrosion and deterioration of the reactor, which not only poses a safety problem, but also produces iron carbonyl or nickel carbonyl due to corrosion, which has an adverse effect on reaction results. effect.

Those skilled in the art have traditionally known that Hastelloy C, Hastelloy F, tantalum,
Reactors made of materials such as titanium, tantalum-titanium alloy, and Inconel 600 are used. However, these metal materials are high-grade materials that contain a large amount of nickel, and the use of reactors using such metal materials has a significant impact on equipment costs, and it is unlikely that economic efficiency will be significantly impaired. It's obvious.

As described above, in order to industrially implement the method of producing ethanol from synthesis gas, a reactor is required that is not attacked by the above-mentioned corrosive components and is made of an economical material.

(Means for Solving the Problems) In order to solve these problems, the present inventors conducted intensive studies on the material of the reactor. As a result, it was discovered that austenitic stainless steel containing molybdenum is hardly corroded in a liquid-phase homogeneous catalytic reaction using a ruthenium compound, a cobalt compound as a catalyst, and a halogen compound as a co-catalyst. It was completed.

That is, the present invention provides a method for producing oxygen-containing compounds such as methanol and ethanol by bringing synthesis gas into contact with a liquid medium containing a ruthenium compound, a cobalt compound, and a halogen compound under high temperature and pressure. This method of producing ethanol is characterized by using a reactor made of austenitic stainless steel.

As the ruthenium compound used in the method of the present invention, any ruthenium compound can be used as long as it forms a complex having carbon monoxide coordination under the reaction conditions. Examples of these include ruthenium metal, as well as
Ruthenium oxides such as ruthenium dioxide and ruthenium tetroxide, their hydrates, mineral acid salts of ruthenium such as ruthenium chloride, ruthenium iodide, and ruthenium nitrate;
Examples include organic acid 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 triruthenium dodecacarbonyl, and ruthenium combined with oxygen, sulfur, halogen, nitrogen, phosphorus,
Examples include ruthenium complexes coordinated with ligands containing arsenic, antimony, bismuth, etc., and their salts.

Among these ruthenium compounds, ruthenium oxide, ruthenium halide, ruthenium carbonyl, ruthenium acetylacetonate, or a ruthenium complex in which at least some of the carbon monoxide ligands of ruthenium carbonyl are replaced with other ligands. etc. are preferable.

The amount of ruthenium compound used in the method of the invention in the liquid medium, expressed as weight in terms of ruthenium metal, is
It ranges from 0.1 to 300 parts by weight per 1000 parts by weight of liquid medium.

In addition to metal cobalt, cobalt compounds include cobalt oxide, cobalt hydroxide, cobalt chloride, cobalt iodide, cobalt mineral salts such as cobalt nitrate, cobalt acetate, cobalt benzoate, and cobalt naphthenate. These include organic acid salts of cobalt. Other coordination compounds can also be used, such as cobalt carbonyl, such as dicobalt octacarbonyl, tetracobalt dodecacarbonyl, cyclobencundienyl cobalt dicarponyl, and cobalt with oxygen. Examples include cobalt complexes coordinated with ligands containing sulfur, halogen, nitrogen, phosphorus, arsenic, antimony, bismuth, etc., and their salts. Among these cobalt compounds, at least some of the carbon monoxide ligands of cobalt oxide L cobalt halide, cobalt carbonyl, cobalt organic acid salt, cobalt acetylacetonate, or cobalt carbonyl are replaced with other ligands. Cobalt complexes and the like are preferred.

The amount of ruthenium compound used in the method of the invention in the liquid medium, expressed as weight in terms of ruthenium metal, is
It ranges from 0.1 to 300 parts by weight per 1000 parts by weight of liquid medium.

The amount of the cobalt compound used in the method of the invention in the liquid medium is between 0.1 and 100 gram atoms, preferably 1 gram atom of cobalt per gram atom of ruthenium.
~10 gram atoms.

Further, in the method of the present invention, it is necessary to use a halogen compound as a co-catalyst in addition to the ruthenium compound and the cobalt compound. 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, alkaline earth metal salts, ammonium salts, quaternary Examples include salts such as phosphonium salts and iminium salts, and hydrocarbon halides such as alkyl halides and aryl halides. Further, hydrogen halides, acid halides, transition metal halides, and the like can also be used. More specifically, (1) examples of metal salts include lithium chloride, lithium bromide, lithium iodide, sodium chloride, potassium bromide, cesium iodide, magnesium chloride, lanthanum iodide, etc.; (2) ammonium salts; Examples include trimethylammonium chloride, trimethylammonium bromide, trimethylammonium iodide, dimethylethylammonium chloride,
Methyldiethylammonium iodide, tetramethylammonium chloride, tetramethylammonium iodide, tetraphenylammonium chloride, cetyltriethylammonium bromide, etc. (3
) Examples of quaternary phosphonium salts include tetraphenylphosphonium chloride, tetra-n-butylphosphonium bromide, n-hebutyltriphenylphosphonium bromide, benzyltriphenylphosphonium iodide, methyltriphenylphosphonium chloride, etc. (4) iminium salts Examples include bis(triphenylphosphine)iminium chloride, bis(triphenylphosphine)iminium bromide, bis(triphenylphosphine)iminium iodide, and at least a portion of the phenyl groups of these iminium compounds are methyl groups. and iminium salts substituted with ethyl groups, etc. (5)
Examples of alkyl halides include methyl chloride, methylene chloride, chloroform, carbon tetrachloride, methyl iodide, ethyl iodide, benzyl chloride, benzyl iodide, etc. (6)
Examples of hydrogen halides include hydrogen chloride, hydrogen bromide, hydrogen iodide, and (7) examples of acid halides.
Examples of the (8) transition metal halides include acetyl chloride and acetyl bromide, as well as nickel chloride, ruthenium chloride, and copper iodide.

Moreover, iodine, chlorine gas, and bromine gas can also be used.

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 in the range of 0.1 to 200 gram atoms of halogen per 1 gram atom of ruthenium, more preferably 1 to 200 gram atoms.
In the 50 gram atom range.

The method of the invention is carried out in a liquid medium. The liquid medium used is preferably an aprotic liquid solvent.

For example, saturated and aromatic hydrocarbons such as heptane, octane, cyclohexane, decalin, tetralin, kerosene, benzene, toluene, xylene, durene, hexamethylbenzene, chloropencune, 0-dichlorobenzene, p-chlorotoluene, fluorocarbons, etc. Halogenated hydrocarbons such as benzene, dioxane, tetrahydrofuran, ethyl ether, anisole, phenyl ether,
Ethers such as diglyme, tetraglyme, 18-crown-6, esters such as methyl acetate, ethyl butyrate, methyl benzoate, T-butyrolactone, acetone,
Ketones such as acetophenone and benzophenone, N-
Methylpyrrolidin-2-one, N-ethylpyrrolidine-
N-substituted amides such as 2-one, N, N-dimethylacetamide, N-methylpiperidone, hexamethylphosphoric triamide, N, N-diethylaniline,
3 such as N-methylmorpholine, pyridine, quinoline, etc.
amines, sulfones such as sulfolane, sulfoxides such as dimethyl sulfoxide, urea derivatives such as 1゜3-dimethyl-2-imidabridinone, and
triethylphosphine oxide, tri-n-propylphosphine oxide, tri-n-butylphosphine oxide, tri-n-hebutylphosphine oxide,
Oxides of trivalent organic phosphorus compounds such as tri-n-octylphosphine oxide, triphenylphosphine oxide, tri-P-)lylphosphine oxide, tri-p-chlorophenylphosphine oxide, and tributylphosphine oxide, ethers, and trivalent organic Examples include oxides of phosphorus compounds.

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

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

In the method of the present invention, the reaction temperature is in the range of 160 to 300°C, preferably in the range of 180 to 260°C. When the reaction temperature is less than 160°C, the reaction between carbon monoxide and hydrogen is extremely slow. Furthermore, when the reaction temperature exceeds 300°C, the amount of methane by-product increases significantly, and the selectivity of ethanol decreases.

In addition, the reaction pressure is in the range of 150 to 800 kg/c G,
Preferably it is in the range of 300 to 500 kg/c+lIG. Anti=11 Although a higher pressure is preferable for the reaction between carbon oxide and hydrogen, a pressure of 800 kg/cJG or less is preferable for practical use.

The molar ratio of carbon monoxide and hydrogen used as raw materials is 1:
A range of 10 to 10:1 is preferred. However, even in extreme cases such as the use of carbon oxide in the presence of water or the use of pure hydrogen in the presence of carbon dioxide, it is possible to carry out the method of the present invention by selecting the reaction conditions. be.

Further, other components inert to the present invention, such as methane, nitrogen, etc., may be present in the raw material synthesis gas.

In the method of the present invention, methods for condensing unreacted synthesis gas below the reaction temperature and separating non-condensable gases are methods known to those skilled in the art. For example, a method is usually used in which unreacted synthesis gas is passed through a cooling pipe and separated into a condensate and non-condensable gas in a gas-liquid separator. The cooling temperature at this time is in the range of -5 to 100°C, preferably 30 to 100°C.

The molybdenum-containing austenitic stainless steel used in the method of the present invention is SUS-316 or 5US-316L.

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

In FIG. 1, a test metal piece is attached to a reactor (1) so as to be in contact with a liquid phase portion and a gas phase portion. Further, the reactor (1) holds a ruthenium compound and a halogen compound, or a liquid solvent containing a ruthenium compound, a cobalt compound, and a halogen compound.

The raw material synthesis gas is passed through the conduit (6) to the reactor (1).
supplied to Also, so that the concentration of catalyst components such as ruthenium, halogen and solvent in the reactor is kept constant, these are fed through conduits (10).

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

The produced ethanol and the co-produced by-products are entrained by the synthesis gas flowing unreacted in the liquid medium and led through the conduit (7) to the cooler (2). Here, the ethanol and by-products are cooled and passed through a high-pressure gas-liquid separator (
In step 3), it is separated into a liquid phase containing non-condensable gas and condensate.

Industrially, this non-condensable gas is recycled back to the reactor.

The gas phase led into conduit (8) is accompanied by small amounts of products such as methanol. On the other hand, the liquid phase is led to the conduit (9). The gas phase introduced into the conduit (8) is removed through the pressure regulating valve (4), and the liquid introduced into the conduit (9) is removed through the level regulating valve (5).

(Function) In the present invention, when producing ethanol by bringing raw material synthesis gas into contact with a liquid-phase homogeneous catalyst whose main catalyst is a ruthenium compound, a cobalt compound, and a halogen compound, the material of the reactor is austenite containing molybdenum. Use stainless steel. According to this method, corrosion of the material is extremely small even under highly corrosive catalyst and reaction conditions.

As a result, there is no need to use a reactor made of expensive materials such as Hastelloy C or titanium, and the cost of the reactor is significantly reduced.

That is, the method of the present invention improves C1 chemistry technology to an industrial level compared to conventional methods.

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

Example 1 A test metal piece cut into 30 mm length, 15 mm width, and 2 mm thickness was polished with 41500 sandpaper, washed with acetone, and dried at 100°C for 30 minutes to produce a test metal piece.

12 g (56 mg atoms as Ru) of triruthenium dodecacarbonyl (Rua(CO)+z ), 28.
88 (168 mg atoms as Co) dicobalt octacarbonyl (Coz(Go)a), 47.6 g
(1123 mg atoms as CI) of lithium chloride (LiCI) and ? A capacity of 560g of tributylphosphine oxide (BusPO) was installed so that five types of test metal pieces were in contact with the liquid phase and gas phase. After the reactor is closed, the molar ratio of carbon monoxide and hydrogen is 1:1 from the bottom of the reactor.
Synthesis gas No. 2 was fed little by little. When the pressure of the reactor reached 320 kg/cJG, temperature increase was started. Synthesis gas was supplied when the temperature of the reactor reached 300°C, and the gas was supplied at a space velocity of 2500/hour while maintaining the reaction pressure at 495 kg/cJG. At the same time, the ruthenium compound, halogen, and solvent were supplied from the bottom of the reactor so that the catalyst concentration within the reactor did not change.

Corrosion tests were conducted in this manner for a total of 100 hours.

Through the liquid level control valve (5), 420 g of the product liquid containing by-products such as ethanol and methanol and methyl acetate was collected per hour.

Table 1 shows the degree of corrosion per year determined from the weight change of the metal pieces before and after the reaction.

Table 1 (Effects of the invention) As the material, SUS-316 or 5US-316
L has no corrosion at all in the liquid phase part of the reactor, and even in the liquid phase part, the degree of corrosion per year is 0.048 mm.
and 0.046 mm.

As described above, by using the method of the present invention, ethanol can be produced using ruthenium compounds, cobalt compounds, and halogen compounds as catalysts without using reactors made of expensive materials such as Hastelloy C1 and Inconel 600. can do.

[Brief explanation of the drawing]

FIG. 1 shows an example of a manufacturing flow sheet for implementing the present invention. In the figure, each symbol is as follows. 1 reactor, 2 cooler, 3 high pressure gas-liquid separator, 4 pressure reducing valve, 5 liquid level control valve

Claims (1)

[Claims] (1) In a method for producing oxygen-containing compounds such as methanol and ethanol by bringing carbon monoxide and hydrogen into contact with a liquid medium containing a ruthenium compound, a cobalt compound, and a halogen compound under high temperature and pressure, the material contains molybdenum. A method for producing ethanol, characterized by using a reactor made of austenitic stainless steel.