JPS629573B2 - - Google Patents

Description

[Detailed description of the invention]

FIELD OF INDUSTRIAL APPLICATION The present invention relates to a process for producing ethylene glycol from synthesis gas, ie a mixture of carbon monoxide and hydrogen. Ethylene glycol is an extremely important chemical product industrially as a raw material for polyester fibers, a raw material for organic solvents, a non-volatile antifreeze solution, and the like. [Prior Art] Ethylene glycol has conventionally been produced by an oxidation reaction of ethylene. In recent years, as a method for producing ethylene glycol, a technology has been developed that uses synthesis gas, which is a cheaper and more abundant raw material than ethylene, as a raw material. For example, Special Publication No. 53-31122, Special Publication No. 55-43821
No., Special Publication No. 53-15047, Special Publication No. 50-32118, Special Publication No. 56-40131, Special Publication No. 55-5497, Special Publication No. 55
−33694, Special Publication No. 55-33697, Japanese Patent Publication No. 1973-
No. 125203, Special Publication No. 10894, Special Publication No. 1983-40698
No., JP-A-52-42809, JP-A-52-42810, JP-A-56-40132, JP-A-53-121714, JP-A-Sho.
No. 54-71098, JP-A-54-48703, JP-A-54-
No. 92903, JP-A-54-16415, JP-A-54-122211
No., JP-A-55-9065, JP-A-53-108889, JP-A-56-75498, JP-A-57-128645, JP-A-Sho.
57-130941 and Japanese Patent Application Laid-open No. 57-130942, as well as U.S. Patent Nos. 4013700 and 4199520,
No. 4133776, No. 4151192, No. 4153623, No. 4225530,
No. 4199521, No. 4190598, No. 4211719, and No. 4302547
As described in the specifications of No. 1, a method of reacting carbon monoxide and hydrogen using a rhodium catalyst under high temperature and high pressure conditions is well known. [Problems to be solved by the invention] However, the methods of the prior art exemplified above have not yet achieved sufficient catalytic activity to justify the use of expensive rhodium, and therefore cannot be implemented on an industrial scale. As a method, it had problems such as being difficult to adopt. [Means for Solving the Problems] The present inventors have arrived at the present invention as a result of taking the above facts into consideration and making intensive studies to increase the activity of rhodium catalysts. That is, the present invention provides carbon monoxide and hydrogen in a liquid phase in the presence of a catalyst containing rhodium and at least one trialkylphosphine selected from the group consisting of branched alkylphosphines and cyclic alkylphosphines. In the method of producing ethylene glycol by reaction, saturated aliphatic polycarboxylic acids, cycloaliphatic polycarboxylic acids, unsaturated aliphatic polycarboxylic acids, and aliphatic polycarboxylic acids containing hydroxy groups or oxo groups are added to the reaction system. The gist of the present invention is a method for producing ethylene glycol, characterized in that at least one selected from the group consisting of carboxylic acids is present. The present invention will be explained in more detail below. The raw material gases used in the present invention, that is, the carbon monoxide and hydrogen sources, are not particularly limited.
It may contain some amount of inert gas such as nitrogen gas or carbon dioxide. The volume ratio of hydrogen and carbon monoxide is usually in the range of 1/10 to 10/1,
It is preferable to use one having a composition in the range of 1/55/1. In the present invention, rhodium and trialkylphosphine are present as catalyst components. As for the supply form of the rhodium component, any rhodium metal or rhodium compound capable of forming a rhodium carbonyl compound in the reaction zone can be used. Specific examples of the rhodium compound include zero-valent compounds such as dirhodium octacarbonyl; rhodium acetylacetonatodicarbonyl;
Monovalent complex compounds such as chlorodicarbonyl rhodium dimer; salts such as rhodium trichloride and rhodium nitrate; oxides such as rhodium trihydroxide; trivalent complex compounds such as tris(acetylacetonato)rhodium; tetrarhodium dodecacarbonyl, There are clusters such as hexalodium hexadecacarbonyl; anion chains such as rhodium tetracarbonyl anion and carbidehexarodium pentadecacarbonyl dianion. The amount of rhodium used is expressed as the concentration in the reaction solution.
Usually 0.0001 to 10 gram atoms per reaction solution,
Preferably it is in the range of 0.001 to 1 gram atom. In addition, the above-mentioned trialkylphosphines include tri-iso-butylphosphine, tris(2-ethylhexyl)phosphine, tri-iso-propylphosphine, tri-sec-butylphosphine, tri-t-butylphosphine, etc. Branched alkylphosphine; cyclic alkylphosphine such as tricyclopentylphosphine and tricyclohexylphosphine. The amount of the above-mentioned trialkylphosphine used is 0.2 to 1000 mol per gram atom of rhodium.
Preferably 0.5 to 100 mol, more preferably
It ranges from 0.8 to 10 moles. The method of the present invention further uses an aliphatic polycarboxylic acid which acts as a reaction accelerator. As these aliphatic polyhydric carboxylic acids, those having about 2 to 20 carbon atoms are usually used. The aliphatic polycarboxylic acids include oxalic acid,
Malonic acid, methylmalonic acid, ethylmalonic acid, ethylmethylmalonic acid, succinic acid, glutaric acid, β
- Saturated aliphatic polycarboxylic acids such as ethyl glitaric acid, β, β-ethylpropylglutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, hexadecanedioic acid; 1,1-cyclobutanedicarboxylic acid, cis-1, 3-cyclobutanedicarboxylic acid, trans-1,3-cyclobutanedicarboxylic acid, 1,1-cyclopropanedicarboxylic acid,
1,1-cyclohexanedicarboxylic acid, 1,1-
Cyclobentanedicarboxylic acid, cis-1,2-cyclopentanedicarboxylic acid, trans-1,2-cyclopentanedicarboxylic acid, cis-1,3-cyclopentanedicarboxylic acid, trans-1,3-cyclopentanedicarboxylic acid, 1 , 2,4-cyclohexanetricarboxylic acid, α-camphoric acid,
Cycloaliphatic polycarboxylic acids such as cis, cis, cis-1,2,3,4-cyclopentanetetracarboxylic acid; maleic acid, fumaric acid, mesaconic acid, itaconic acid, 1,2,3-propene Torcarboxylic acid,
Unsaturated aliphatic polycarboxylic acids such as acetylene dicarboxylic acid; tartaric acid, citric acid, malic acid, 3-
Hydroxy group- or oxo group-containing aliphatic polycarboxylic acids such as oxoglutaric acid are used. The amount of the aliphatic polycarboxylic acid used is usually in the range of 0.1 to 200 mol, preferably in the range of 0.5 to 100 mol, per gram atom of rhodium. Although the present invention can be carried out in the absence of a solvent, ie, the reaction raw materials and catalyst components themselves are used as a solvent, a solvent can also be used. Examples of such solvents include ethers such as diethyl ether, anisole, tetrahydrofuran, ethylene glycol dimethyl ether, and dioxane;
Ketones such as acetone, methyl ethyl ketone, acetophenone; alcohols such as methanol, ethanol, n-butanol, benzyl alcohol, phenol, ethylene glycol, diethylene glycol; carboxylic acids such as formic acid, acetic acid, propionic acid, toluic acid; methyl acetate, acetic acid Esters such as n-butyl and benzyl benzoate; Aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and tetralin; n-hexane, n-octane,
Aliphatic hydrocarbons such as cyclohexane; halogenated hydrocarbons such as dichloromethane, trichloroethane, and chlorobenzene; nitro compounds such as nitromethane and nitrobenzene; carboxylic acids such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone Amides such as amide, hexamethylphosphoric acid triamide, N,N,N',N'-tetraethylsulfamide;N,N'-dimethylimidazolidone,N,N,N',N'-tetramethylurea, etc. Sulfones such as dimethyl sulfone and tetramethylene sulfone; Sulfoxides such as dimethyl sulfoxide and diphenyl sulfoxide; Lactones such as γ-butyrolactone and ε-caprolactone; Polyethers such as tetraglyme and 18-crown-6 Nitriles such as acetonitrile and benzonitrile; Carbonate esters such as dimethyl carbonate and ethylene carbonate. Among the above solvents, it is preferable to use aprotic polar solvents, ie amides, ureas, sulfones, sulfoxides, lactones, polyethers, nitrites and carbonate esters. Particularly preferred are aprotic polar solvents with a dielectric constant of 20 or more. The reaction of the present invention can be carried out in either a homogeneous system or a heterogeneous suspension system. The reaction temperature is usually 100 to 300°C, but a more preferable temperature range is about 150 to 250°C. The reaction pressure is usually 50 kg/cm ² or higher, preferably about 250 to 750 kg/cm ² . The method of the present invention can be carried out in any batch, semi-continuous or continuous reaction mode. Oxygen-containing compounds produced by the reaction, ie, ethylene glycol, methanol, etc., can be separated by conventional separation methods such as distillation. Furthermore, the distillation residue can be recycled and reused as a reaction catalyst liquid. [Examples] The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded. The amount of product produced is determined by the unit amount of rhodium atoms and the turnover number (mol/g-atom), which indicates the number of moles of product produced per unit reaction time.
expressed in Rh/hr). Example 1 In a Hastelloy C autoclave with an internal volume of 35 c.c., acetylacetonatobis(carbonyl)rhodium [Rh
(CO) ₂ (acac)], tri-iso-propylphosphine 0.1 mmol and adipic acid 0.1 mmol and N,
Add 10ml of N′-dimethylimidazolidinone,
Furthermore, an equal volume mixture of carbon monoxide and hydrogen is added at room temperature.
It was filled up to 300Kg/cm ² . The initial value of the reaction pressure when the autoclave temperature is raised to 220℃ is 470
It was Kg/ ^cm2 . After continuing the reaction for 2 hours, the autoclave was cooled and the contents were taken out and analyzed by gas chromatography. As a result, 17.08 mol/g-atom Rh・hr of ethylene glycol and 13.42 mol/g-atom Rh・It was confirmed that hr methanol was being produced. Examples 2 to 4 and Comparative Examples 1 to 2 Reactions were carried out in the same manner as in Example 1, except that aliphatic polycarboxylic acids shown in Table 1 were used instead of adipic acid. The results are shown in Table-1.

[Table] The reaction was carried out without.
Example 5 The reaction was carried out in the same manner as in Example-1 except that tri-iso-propylphosphine was changed to tricyclohexylphosphine. As a result, 8.63 mol/g-
atom Rh・hr ethylene glycol and 25,
It was confirmed that methanol of 0.8 mol/g-atom Rh/hr was produced. Comparative Example 3 The reaction was carried out in the same manner as in Example 5, except that adipic acid was not added. As a result, 4.59 mol/g
atom Rh・hr ethylene glycol and 12.35mol/
It was confirmed that g-atom Rh/hr methanol was produced. Examples 6 and 7 The reaction was carried out in the same manner as in Example 1 except that 0.1 mmol of fumaric acid (Example 6) or 0.1 mmol of tartaric acid (Example 7) was used instead of adipic acid. Results are shown in Table-2.

〔effect〕

According to the method of the present invention, it is possible to produce ethylene glycol at a high level of yield that could not be achieved using conventional catalyst systems.

Claims (1)

[Claims] 1. Ethylene glycol is produced by reacting carbon monoxide and hydrogen in a liquid phase in the presence of a catalyst containing rhodium and at least one trialkylphosphine selected from the group consisting of branched alkylphosphines and cyclic alkylphosphines. In the method for producing , the reaction system contains a group consisting of saturated aliphatic polycarboxylic acids, cycloaliphatic polycarboxylic acids, unsaturated aliphatic polycarboxylic acids, and aliphatic polycarboxylic acids containing hydroxy or oxo groups. A method for producing ethylene glycol, characterized in that at least one aliphatic polycarboxylic acid selected from the following is present.