JPS6341894B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for directly producing ethanol from carbon monoxide and hydrogen (hereinafter referred to as synthesis gas). More specifically, the present invention relates to a method for directly synthesizing methanol and ethanol from synthesis gas by a liquid phase catalytic reaction carried out in the presence of a catalyst containing a ruthenium compound and a chlorine or bromine compound as main components. Methanol or ethanol is a compound that has a wide range of uses as an intermediate raw material or solvent for various chemicals. (Prior Art) A method for producing methanol and/or ethanol using carbon monoxide and hydrogen as raw materials in the presence of a ruthenium-containing catalyst is known. For example, a method for directly producing methanol, ethylene glycol, and ethanol or their carboxylate derivatives by reacting hydrogen and carbon monoxide in a suitable solvent containing a solubilized ruthenium carbonyl complex (Japanese Patent Application Laid-Open No. 55-115834) ), a method for producing acetaldehyde and/or ethanol by reacting carbon monoxide with hydrogen in the presence of a catalyst system consisting of a ruthenium source and a halide source (Japanese Patent Application Laid-Open No. 166133/1989), and a method for producing acetaldehyde and/or ethanol in a homogeneous manner A method for selectively producing methanol and ethanol by bringing a ruthenium catalyst, a halogen or halide promoter, and an organic oxidized phosphine compound into contact with carbon monoxide and hydrogen (Japanese Patent Application Laid-open No. 82327-1982)
Examples include. However, it is still necessary to industrialize the known technology.
Both methanol and ethanol activity and selectivity are insufficient. One reason for this is that acetic acid and acetic acid esters produced as by-products relatively reduce the proportion of the target alcohol in the product. (Problems to be Solved by the Invention) An object of the present invention is to provide a method for producing methanol and ethanol with increased selectivity in a direct one-step reaction using carbon monoxide and hydrogen as raw materials. That's true. (Means for Solving the Problems) The present inventors have made extensive studies to solve these problems. As a result, in a liquid phase homogeneous reaction using a ruthenium catalyst, acetic acid and/or an ester of acetic acid are supplied to the reaction system, thereby
The present inventors have discovered a method for selectively producing methanol and ethanol by reducing the net amount of acetic acid produced, leading to the present invention. That is, the present invention provides a method for producing alcohol by contacting a catalyst mainly composed of a ruthenium compound and a chlorine compound or a bromine compound with carbon monoxide and hydrogen under high temperature and pressure. This is a method for producing alcohols, characterized in that acetic acid and/or esters of acetic acid are supplied to a reaction system in an amount such that the net production amount is zero. 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 the reaction conditions. Examples of these include, in addition to metallic ruthenium, 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, ruthenium acetate, Examples include organic acid salts of ruthenium such as 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, ruthenium combined with oxygen,
Examples include ruthenium complexes and their salts coordinated with ligands containing sulfur, halogen, nitrogen, phosphorus, arsenic, antimony, bismuth, etc. Among these ruthenium compounds, ruthenium oxide, ruthenium halide, ruthenium carbonyl, ruthenium acetylacetonate,
Alternatively, a ruthenium complex in which at least some of the carbon monoxide ligands of ruthenium carbonyl are replaced with other ligands is preferable. The amount of the ruthenium compound used in the method of the present invention in the liquid medium is 0.1 to 300 parts by weight per 1000 parts by weight of the liquid medium in terms of ruthenium metal.
Parts by weight range. Further, in the method of the present invention, it is necessary to use a halogen compound as a promoter for the ruthenium 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 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. Further, hydrogen halides, acid halides, transition metal halides, and the like can also be used. More specifically, examples of metal salts include lithium chloride, lithium bromide, lithium iodide, sodium chloride, potassium bromide, cesium iodide, magnesium chloride, and lanthanum iodide; examples of ammonium salts include trimethylammonium Quaternary phosphonium salts such as chloride, trimethylammonium bromide, trimethylammonium iodide, dimethylethylammonium chloride, methyldiethylammonium iodide, tetramethylammonium chloride, tetramethylammonium iodide, tetraphenylammonium chloride, cetyltriethylammonium bromide, etc. Examples include tetraphenylphosphonium chloride, tetra n-butylphosphonium bromide,
Examples of iminium salts include bis(triphenylphosphine)iminium chloride, bis(triphenylphosphine)iminium bromide, n-heptyltriphenylphosphonium bromide, benzyltriphenylphosphonium iodide, methyltriphenylphosphonium chloride, etc. Examples of alkyl halides include methyl chloride, chloride, etc., such as bis(triphenylphosphine)iminium iodide and iminium salts in which at least a portion of the phenyl group of these iminium compounds is substituted with a methyl group, ethyl group, etc. methylene, chloroform, carbon tetrachloride, methyl iodide,
Examples of hydrogen halides include hydrogen chloride, hydrogen bromide, and hydrogen iodide; examples of acid halides include acetyl chloride and acetyl bromide; and transition metals such as acetyl chloride and acetyl bromide. Examples of halides include nickel chloride, ruthenium chloride, copper iodide, etc. Iodine, chlorine gas, and nitrogen 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 per gram atom of ruthenium is:
The halogen atoms range from 0.1 to 200 gram atoms, more preferably from 1 to 50 gram atoms. The method of the invention can be carried out in a liquid medium. The liquid medium used is preferably an aprotic liquid solvent. For example, heptane, octane, cyclohexane, decalin, tetralin, kerosene, benzene, toluene, xylene, diyulene,
Saturated and aromatic hydrocarbons such as hexamethylbenzene, halogenated hydrocarbons such as chloropentane, o-dichlorobenzene, p-chlorotoluene, fluorobenzene, dioxane, tetrahydrofuran, ethyl ether, anisole,
Ethers such as phenyl ether, diglyme, tetraglyme, 18-crown-6, ketones such as acetone, acetophenone, benzophenone, N-methylpyrrolidin-2-one, N-ethylpyrrolidin-2-one, N,N - N-substituted amides such as dimethylacetamide, N-methylpiperidone and hexamethylphosphoric triamide; tertiary amines such as N,N-diethylaniline, N-methylmorpholine, pyridine and quinoline; sulfones such as sulfolane; Examples include sulfoxides such as dimethyl sulfoxide, urea derivatives such as 1,3-dimethyl-2-imidazolidinone, phosphine oxides such as tributylphosphine oxide, and silicone oil. Among these, particularly preferred liquid solvents include saturated hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, ethers, and phosphine oxides. These liquid solvents can be used alone or in combination of two or more. Further, if the liquid solvent used in the method of the present invention is liquid at least under the reaction conditions,
It can be used even if it is solid at room temperature and pressure. In the method of the present invention, acetic acid and/or acetic acid ester are supplied to the reaction system. Forms of acetic acid include, in addition to acetic acid, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, and the like. It is also possible to use acetates such as ammonium acetate, calcium acetate, cobalt acetate, and the like. Among these compounds, acetic acid and methyl acetate are particularly preferred. These compounds can be used alone or in combination of two or more. The supply of acetic acid, acetate ester, and/or acetate to the reaction system is such that the net production amount of acetic acid is 0.
It is preferable to do so. The amount of acetic acid and/or acetic ester that will make the net amount of acetic acid produced is 0, is actually determined by gradually changing the amount of these supplied to the reaction system so that the net amount of acetic acid produced becomes 0. This amount is usually determined by determining the amount of acetic acid, but usually this amount is approximately twice or more of the acetic acid produced when acetic acid and/or acetate ester are not added to the reaction system. In this manner, the amount of acetic acid and/or acetate ester to be supplied to the reaction system is determined in advance, and this predetermined appropriate amount is supplied to the reaction system prior to the start of the reaction. Such a supply is advantageous in industrial processes where the recovered acetic acid and acetate are recycled back to the reactor. As the amount supplied to the reaction system increases, the net amount of acetic acid produced decreases, and the amount supplied is adjusted so that it becomes zero. However, if too large a quantity is supplied, the activity of the catalyst will decrease, which is not preferable. Here, the net amount of acetic acid produced is calculated from the total amount of acetic acid after the reaction and the amount of acetic acid esters converted to acetic acid, the amount of acetic acid supplied, and when using acetate esters or acetates, , excluding the total amount converted into acetic acid. The molar ratio of carbon monoxide and hydrogen used as synthetic raw materials in the method of the present invention is usually 1:
The ratio is 10 to 10:1, preferably 1:3 to 2:1. It is also possible to use other inert components such as methane and nitrogen in the synthesis gas. 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. At reaction temperatures below 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. Moreover, the reaction pressure is in the range of 150 to 800 Kg/cm ² , preferably in the range of 300 to 500 Kg/cm ² . The higher the reaction pressure is, the more preferable it is for the reaction between carbon monoxide and hydrogen, but for practical purposes, a pressure of 800 Kg/cm ² or less is preferable. The method of the present invention can be carried out in a batch, semi-continuous or continuous manner. In the process of the invention, the acetic acid and/or esters of acetic acid fed may initially be added to the reactor batchwise, or may be fed semi-continuously or continuously. (Function) In the present invention, in a method for producing ethanol by bringing a raw material gas into contact with a catalyst containing a ruthenium compound and a halogen compound, acetic acid and/or
Alternatively, by supplying esters of acetic acid to the reaction system, the net amount of acetic acid produced can be reduced and the proportions of methanol and ethanol in the produced product can be relatively increased. According to this method, the selectivity of ethanol can be increased, and the recovered acetic acid and/or esters of acetic acid can be recycled and used, so it is an industrial method. That is, compared to the conventional method, the method of the present invention has the following advantages:
C ₁ It aims to improve chemical technology to an industrial level. (Example) Hereinafter, the method of the present invention will be explained in more detail with reference to Examples and Comparative Examples. Example 1 In a stainless steel autoclave with a capacity of 50ml
0.28 mg atoms of triruthenium dodecacarbonyl [Ru ₃ (CO) ₁₂ ], 3.5 mmole of bis(triphenylphosphine)iminium chloride [(φ ₃ P) ₂ NCl], 0.84 mmole of hydrogen bromide, 10.2 m
Add mole of acetic acid and 15 ml of toluene, and add synthesis gas (CO:H ₂ molar ratio 1:1) at 340 °C at room temperature.
It was press-fitted up to Kg/ ^cm2 . The autoclave was heated with stirring, the internal temperature was maintained at 240°C, and the reaction was carried out for 1 hour. During this time, the internal pressure of the autoclave is 458-420
It changed to Kg/ ^cm2 . 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 gas chromatography. The results are shown in Table 1. Examples 2 to 6 and Comparative Examples 1 to 5 In the method of Example 1, ruthenium compound concentration, amount of acetic acid added, type of halogen compound, concentration of halogen compound, type of additive, concentration of additive, type of solvent The reaction temperature was changed as shown in Table 1. The reaction results are shown in Table 1. Example 7 In Example 1, the reaction was carried out using 12.9 mmole of methyl acetate instead of acetic acid. The substantial reaction products were methanol, ethanol, methane, etc., and no substantial production of acetic acid was observed.

[Table] In Table 1, each symbol represents the following compound. Ru: triruthenium dodecacarbonyl PPNCl: bis(triphenylphosphine)iminium chloride LiCl: lithium chloride Me ₃ NHBr: trimethylammonium bromide HCl: hydrochloric acid HBr: hydrobromic acid Toluene: toluene NMP: N-methylpyrrolidine- 2-one MeOH, EtOH, and AcOH are the values obtained by converting the generated ester into the corresponding methanol, ethanol, and acetic acid, and adding them. The amount of product represents the net amount produced. In Example 9, methyl acetate was used instead of acetic acid. The amount shown is the amount of acetic acid equivalent to the methyl acetate added. (Effects of the Invention) Comparative Example 1 is the result when acetic acid was not added, and the ratio of alcohol (methanol + ethanol) in the product was 67.8%. On the other hand, in Example 1, 10.2 mmole of acetic acid, which is more than twice the produced 4.3 mmole of acetic acid, was added in advance, and the alcohol ratio in the product was 77.8.
%. Comparative Examples 2 to 5 also correspond to Examples 2 to 6.
In comparison, the same effect as mentioned above was confirmed. Thus, by using the method of the present invention, the proportion of alcohol in the product can be increased.

Claims (1)

[Claims] 1. In a method for producing alcohol by contacting a catalyst mainly composed of a ruthenium compound and a chlorine compound or a bromine compound with carbon monoxide and hydrogen under high temperature and pressure, a predetermined net production amount of acetic acid is 1. A method for producing alcohols, which comprises supplying acetic acid and/or esters of acetic acid to a reaction system in an amount such that the amount becomes zero prior to the start of the reaction.