JPS5867641A - Synthesizing method of acetic acid - Google Patents

Abstract

PURPOSE:To obtain acetic acid in high selectivity with a little amount of easily removable by-products, e.g. methane and to attain easy removal of the generated heat, by reacting CO with H2 in a liquid medium catalytically in the presence of a ruthenium compound and a cobalt compound and a cocatalyst under pressure. CONSTITUTION:CO is catalytically reacted with H2 in a liquid medium, e.g. haptane or octane, containing a ruthenium compound, e.g. rutheium oxide or ruthenium halide, capable of forming a complex with CO as a ligand, a cobalt compound, e.g. a cobalt halide or cobalt carbonyl, capable of forming a complex with CO as a ligand, and a cocatalyst, e.g. tributylamine or tributylphosphine, under pressure (80-1,000kg/cm<2>.G) to give acetic acid (including acetic acid contained in the form of methyl acetate or ethyl acetate).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for synthesizing acetic acid by a direct liquid phase method using -carbon oxide and hydrogen as raw materials.

- Several examples of the so-called direct method, in which acetic acid is directly synthesized using carbon oxide and hydrogen as raw materials, are known so far. For example, according to JP-A-51-80806 and JP-A-54-41558, carbon monoxide and hydrogen are reacted by a heterogeneous method using rhodium supported on a carrier such as silica gel as a catalyst. By this, hydrocarbons and oxygenated compounds.

A method by which the product is obtained is disclosed. However, in this method, the selectivity of carbon monoxide consumed in the reaction to F acid (hereinafter referred to as acetic acid selectivity) is only as low as about 30%. Moreover, it suffers from the disadvantage that large amounts of hydrocarbons such as methane are formed which are difficult to separate from the unreacted carbon monoxide and hydrogen gas mixture. Furthermore, Japanese Patent Application Laid-Open No. 14706/1983 discloses a method in which a rhodium'-manganese catalyst is used in place of the above-mentioned rhodium in a gas phase heterogeneous method. However, the selectivity of acetic acid is still only about 50%, and it cannot be said that the life cycle of hydrocarbons such as methane has been improved. Further, JP-A-54-138504 and JP-A-54-141705 disclose a method using a catalyst system in which magnesium and a base are added to rhodium, also in the gas phase heterogeneous method. In this method, the selectivity of #acid has improved considerably, but the selectivity does not exceed 601%, and the undesirable methane of one organism is still e%.
~4096 are generated.

There is a strong desire to develop a method for synthesizing acetic acid that improves the drawbacks of the above-mentioned methods already disclosed.

The present inventors have discovered that when carbon monoxide and hydrogen are reacted in a liquid medium using a ruthenium compound and a cobalt compound as catalysts, acetic acid and an acetic acid ester such as methyl acetate or ethyl lrF acid may react depending on the type of cocatalyst. Cyto also found that a high selectivity was obtained and that the by-product of undesirable hydrocarbons such as methane was extremely small, leading to the completion of the present invention.

Acetate esters such as methyl acetate or ethyl acetate obtained by the method of the present invention can be easily obtained by hydrolysis.
It can be converted to toric acid and useful methanol or ethanol.

Acetate esters as they are are useful as industrial products and solvents, and can be separated from the reaction product and obtained as tomic acid esters.

Hereinafter, in the method of the present invention, ffy:f1! contained in the above acetate ester! They are collectively called α-acids.

The ruthenium compound in the method of the present invention refers to a complex formed using carbon oxide as a ligand, and under reaction conditions becomes a ruthenium complex with a carbon monoxide ligand, which dissolves in the liquid medium used. . This complex can be produced using various ruthenium compounds as precursors under reaction conditions. As the precursor ruthenium compound, any ruthenium compound can be used as long as it forms a ruthenium complex having a carbon monoxide ligand under the reaction conditions. Examples of these include, in addition to ruthenium metal, ruthenium oxides such as ruthenium dioxide and ruthenium tetroxide, their hydrates, ruthenium salts such as ruthenium chloride, ruthenium iodide, and ruthenium nitrate, and ruthenium acetate. , Ruthenium 9M organic # such as ruthenium propionate! There are melons, etc. Also,
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, nitrogen, phosphorus, arsenic,
Examples include ruthenium complexes coordinated with ligands containing antimony, bismuth, etc., and their salts.

Among these ruthenium compounds, ruthenium oxides, ruthenium halides, ruthenium carbonyls, and ruthenium complexes in which at least some of the carbon monoxide ligands of ruthenium carbonyl are replaced with other ligands are preferred. L) Also, the cobalt compound is,
Under the reaction conditions, a cobalt complex is formed with a carbon monoxide ligand that is soluble in the liquid medium used.As in the case of ruthenium, the complex can be prepared using various cobalt compound precursors under the reaction conditions. It can be generated below. Therefore, the cobalt compound as a precursor is
Again, anything that provides a cobalt complex with a carbon ligand under the reaction conditions can be used.

Examples of these include, in addition to metallic cobalt, cobalt oxides, cobalt hydroxides, cobalt mineral salts such as cobalt chloride, cobalt iodide, cobalt nitrate, cobalt acetate, cobalt benzoate, and cobalt naphthenate. There are organic acid whispers of cobalt such as. In addition, coordination compounds can also be used, examples of which include dicobalt octacarbonyl, tetracobalt dodecacarbonyl, and tetracobalt dodecacarbonyl.
Cobalt 814, which is cobalt carbonyl such as carbonyl, cyclopentadienyl cobalt dicarbonyl, or cobalt coordinated with a ligand containing lfl, sulfur, halogen, nitrogen, phosphorus, arsenic, antimony, bismuth, etc.
Examples include the body and its salts.

Among these cobalt compounds, cobalt oxides, cobalt halides, cobalt carbonyls, cobalt organic acid groups, and cobalt complexes in which at least some of the carbon monoxide ligands of cobalt carbonyl are replaced with other ligands. is preferred.

Precursors of these ruthenium compounds and cobalt compounds include ruthenium-cobalt heteronuclear clusters such as the above-mentioned ruthenium and cations.

In the process of the present invention, the ruthenium compound and the cobalt compound are each combined with at least one molecule per atom of the monoxide cobalt compound under the reaction conditions to form heteronuclear clusters, such as those mentioned above. Although it is not clear whether a ruthenium compound and a cobalt compound form a complex such as M (OORus(00)13), the effects of the present invention can only be achieved when both a ruthenium compound and a cobalt compound coexist.

In the method of the present invention, it refers to an additive that serves to improve the efficiency of using a cocatalyst.

Such a promoter may include at least one basic compound containing at least one Van element in the periodic table of elements such as nitrogen, phosphorus, arsenic, antimony, and bismuth.
At least one species and/or norogenide is used. Particularly preferably, a combination of a basic compound and a halide brings about a hot effect. The basic compound mentioned here means Lewis basicity, and is a general term for compounds having a lone pair of electrons. At least one of the vB group elements
Examples of basic compounds containing seeds include nitrogen-containing compounds such as amino compounds, imino compounds, nitrilo compounds, adenoids or cryptands,
In addition, as phosphorus-containing compounds, general formulas (1), (11), (
2) or a compound represented by ■R, -〇-P=0 heat R.

(In the formula, R1, - and - represent an alkyl group, an aryl group, an alkaryl group, a cycloalkyl group, etc. having 1 to 20 carbon atoms.) Also, nitrogen-containing compounds,
Examples of antimony-containing compounds or bismuth-containing compounds include compounds in which the phosphorus atom in formula (1) is replaced with an arsenic atom, an antimony atom, or a bismuth atom.

Compounds containing two or more group B atoms, such as diamines and diphosphines, can also be used.

1. The halides include inorganic halides such as halides of alkali metals, alkaline earth metals, rare earth metals, etc.
(%I)l Rs' (In M, R1, Rs, Rs and - are an alkyl group, aryl group, alkaryl group or cycloalkyl group having 1 to 20 carbon atoms, and X- is
Examples include quaternary ammonium salts represented by halogen anions such as Or, Bf-1-, and phosphonium salts in which the nitrogen atom is replaced with a phosphorus atom in formula (7). In addition, 4 containing cyclic amines
Halides in the form of ammonium salts, iminium salts, etc. are also effective in achieving the objects of the present invention.

In the method of the present invention, co-catalysts more preferably used include basic compounds such as amines such as tributylamine, triphenylamine, pyridine and 2-hydroxypyridine, phosphines such as tributylphosphine and triphenylphosphine; Triphenylarsine and triphenylamine mata include substances such as triphenylbismachine, quaternary ammonium halides such as tetrabutylammonium chloride and methylpyridinium bromide, tetraphenylphosphonium chloride, m-heptyltriphenylphosphonium bromide, and benzyl trichloride. Examples include phosphonium halides such as phenylphosphonium chloride, iminium halides such as bistriphenylphosphine iminium chloride, and the like.

The liquid medium used in the method of the invention may be one that can exist as a liquid for at least 1 s under the reaction conditions.

Examples of such liquid media include saturated hydrocarbons and molten salts. These liquid media may be inert with respect to the reaction, such as saturated hydrocarbons, or reactive, such as alcohols, which form esters with the acetic acid produced. Further, it may also be a substance having an effect as a co-catalyst, such as amines.

Additionally, molten salts such as molten quaternary ammonium halides and phosphonium halides can be used as liquid media with halide effects.

Among these liquid media, aprotic liquid media are more preferably used in the method of the present invention. Examples of this include saturated hydrocarbons, aromatics, tetraglyme,
Esters such as methyl acetate, ethyl butyrate, r-butyrolactone, etc., ketones such as acetone, methyl ethyl ketone, acetophenone, amides such as N
, N-dimethylformamide, etc. Also, lactams and their derivatives, such as 2-pyrrolidone, 1-caprolactam, N-methylpyrrolidone, etc., amines, such as ethylamine, ethylenediamine, cyclohexylamine, N-methylaniline, N, N-diethylaniline, morpholine, N-methylmorpholine, pyridine,
Examples include picoline, 2-hydroxypyridine, quinoline, etc., sulfones such as sulfolane, and sulfoxides such as dimethyl sulfoxide.

These liquid media may be used alone or in combination of two or more.

In the method of the present invention, the reaction temperature is not particularly limited, but
The lower limit is set at a temperature that provides a practical reaction rate, and the upper limit is set at a temperature where the -1,carbon partial pressure necessary to solubilize the ruthenium compound and cobalt compound as a catalyst is extremely high. It may be determined so as not to increase the corrosion rate, to prevent the corrosion of the co-catalyst material from accelerating significantly, and to suppress undesirable side reactions that produce methane and the like. Usually the reaction temperature ranges from 150 to 300°, preferably from 170 to 280°.

In addition, in the method of the present invention, the reaction pressure is set to the minimum carbon monoxide partial pressure necessary to solubilize the ruthenium compound and cobalt compound acting as the main catalyst at the reaction temperature, and to maintain a practical reaction rate. The lower limit is limited by the sum of the minimum required hydrogen partial pressures, and the upper limit is limited by economic constraints such as the pressure resistance of the reactor and the power required for the pressure of carbon monoxide and hydrogen as synthesis raw materials. is restricted.

Usually, the reaction pressure ranges from 50 to 5000 #/d gauge, preferably from 80 to 1000 #/cd gauge.

The molar ratio of carbon monoxide and hydrogen used as raw materials for synthesis is stoichiometrically 1:1, but the reaction proceeds satisfactorily even at other molar ratios.

The range of this molar ratio is limited by, for example, reaction rate, acetic acid selectivity, etc. Taking these into consideration, a range of 1:10 to 10:1 is usually used. However, as an extreme example, it is possible to carry out the process of the invention by selecting reaction conditions, such as the use of pure carbon oxide in the presence of water or even the use of pure hydrogen in the presence of carbon dioxide. is possible.

The synthesis raw material gas may contain other components inert to the reaction, such as methane nitrogen. Concentrations typically range from 11 to 100 parts by weight of pure ruthenium and pure cobalt per 1000 parts by weight of liquid medium. In addition, the usage ratio of ruthenium compounds and cobalt compounds is 50% ruthenium:cobalt in atomic ratio.
It is in the range of 0:1 to 1:10.

The amount of cocatalyst used in the process of the present invention is controlled by the amount relative to the amount of ruthenium compound and cobalt compound used as catalysts.

If the amount of co-catalyst is too small, the effect of its addition will not be recognized, but if it is too large, the effect of its addition may be impaired.

The preferred range of the amount added is as follows based on the sum of the number of gram atoms of ruthenium in the ruthenium compound and the number of gram atoms of cobalt in the cobalt compound. That is, for the basic compound containing at least one type of Va group element, the number of moles is α001 to 10 times the sum of the gram atoms of the ruthenium and ruthenium), and
Regarding halides, the number of moles is 1001 to 100 times the sum of the gram atoms of ruthenium and cobalt.More preferably, Q is in the range of 01 to 2 times the mole, and 1 to 60 times the mole, respectively. The method of the present invention can be carried out in a batch, semi-continuous or continuous manner.

The ruthenium and cobalt compounds, cocatalyst and liquid medium may be initially added to the reactor in patch mode or may be fed semi-continuously or continuously; the products may be prepared by known methods such as distillation, It can be extracted by a method such as stripping, and in some cases, the acetate produced can be hydrolyzed to decompose into acetic acid and alcohol, and each can be extracted.

If necessary, the catalyst, cocatalyst and liquid medium can be recycled to the reactor and used again.

The method of the present invention has the following advantages over the conventional direct synthesis method of acetic acid. That is, (1) the selectivity of acetic acid, including acetic acid in acetic acid ester, which is easily converted to acetic acid by hydrolysis, is high.

(When unreacted carbon monoxide and hydrogen are recycled and reused, there is very little generation of hydrocarbons such as methane, which are difficult to remove.

(3) Since the reaction takes place in a liquid phase, a large amount of heat generated during the reaction can be easily removed.

Hereinafter, the method of the present invention will be explained more specifically with reference to Examples.

Example 1 Triruthenium dodecacarbonyl (nus) was placed in a stainless steel autoclave with an internal volume of 5018 mm, and a mixed gas of carbon oxide and hydrogen (CO:H) was charged.

(molar ratio 1:1) was injected at room temperature to 280 V-gauge. The autoclave was heated under stirring, and when the internal temperature reached 220°C, the temperature was maintained for 5 hours to carry out the reaction. During this time, the autoclave internal pressure was 575 to 365.
Changed to kg/d gauge.

Next, the heating of the autoclave was stopped, and after cooling to room temperature, the pressure was released, and the contents were taken out and analyzed by chromatography.

The reaction solution is divided into two phases, and the sum of both phases is:
ito & y75.9119, η methyl torate t5■, ethyl acetate 15.5 mg, methanol (L8119, engineering p) -
17111G and very small amounts of methyl formate were detected.

Traces of methane were detected in the gas phase.

Examples 2 to 2g In Example 1, ruthenium compound-cobalt adduct, basic compound, halide, liquid medium, reaction temperature,
The reaction was carried out by determining the reaction pressure, the molar ratio of carbon oxide and hydrogen, the amount, and the set values. These results, together with Example 1, are described in the first garment.

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

Ru-A;) Riruthenium dodecacarbonyl C
Ru5 (co) l11) Ru-B; cobalt oxide (
Fl, uO2) Co-A; dicobalt octacarbonyl (co, (co) 5) Co-B cobalt chloride (
co, cz4) TPP;) Riphenylphosphine (ph
3p) P; viridi/(C6H1sN) TBr; n-heptyl) I7 phenylphosphonium bromide (nHpPhsPBr) BOI; benzyltriphenylphosphonium chloride (B)ph, pct) yar; sodium iodide G; cammagtyrolactone TPA゛; Triphenylarsine TPB;) Riphenylbismasi/HTBr; n-hexyltriphenylphosphonium bromide BTBr ” n-butyltriphenylphosphonium bromide+++Ct' bistriphenylphosphineiminium chloritetracpBr; cetylpyridinium bromide Example 1
The reaction was carried out in exactly the same manner except for the absence of n-heptyltri7enylphosphonium bromide and triphenylphosphine. Reaction pressure t'1220
34 Q'kind cages were reached at °C.

After the reaction, the reaction solution contained 8.5119 methanol and 2.
, 5 mg of ethanol, and 14 μg of propatool were detected.

1lr1. However, neither methyl acetate nor ethyl acetate was detected.

)1 It was compared horizontally.

Acetic acid, methyl acetate and ethyl acetate were all not detected.

Comparative Example S In Comparative Example 1, the reaction was carried out in exactly the same manner except for the absence of triruthenium dodecacarbonyl.

The reaction pressure reached 580kss/c-gauge.

After the reaction, a small amount of methanol was found in the reaction solution.

m-1, methyl ^1 acid and ethyl acetate were not detected.

patent applicant Kogyo Kei’#Director Ishi & Makoto

Claims (1)

[Scope of Claims] 1) A method for synthesizing acetic acid, which comprises catalytically reacting carbon monoxide and hydrogen under pressure in a liquid catalyst containing a ruthenium compound, a cobalt compound, and a promoter. 2) The co-catalyst is at least one element of group Va in the periodic table of elements.
2. The method according to claim 1, wherein at least one basic compound and/or at least one halide contains a species. 3) The method according to claim 2, wherein the basic compound is at least one compound selected from amines, phosphines, arsines, stipines, and bismachines. The method according to claim 2, which is a compound of 5) The method according to claims 1 to 4, wherein the liquid medium is an aprotic liquid medium. 6) Reaction pressure is 80-1000#/11! The method according to claims 1 to 5, which is a II gauge.