JPS6257171B2 - - 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 chemicals, or a non-volatile antifreeze solution. [Conventional technology] Traditionally, ethylene glycol has been produced by the oxidation reaction of ethylene.In recent years, a method for producing ethylene glycol has been to use synthesis gas, which is a cheaper and more abundant raw material than ethylene, as a raw material. is being developed. 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, and U.S. Patent No. 4013700, 4199520, 4133776
No. 4151192, 4153623, 4225530, 4199521
As described in the specifications of No. 4190598, No. 4211719, and No. 4302547, a method of reacting carbon monoxide and hydrogen using a rhodium catalyst under high temperature and high pressure conditions is well known. ing. [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 a method for producing ethylene glycol by reacting carbon monoxide and hydrogen in a liquid phase in the presence of a rhodium catalyst, which has a trialkylphosphine and 1,4-diazabutadiene skeleton in the reaction system. The gist of the present invention is a method for producing ethylene glycol characterized by the presence of a compound. Hereinafter, the present invention will be explained in detail. The source of the raw material gases used in the present invention, ie, carbon monoxide and hydrogen, is not particularly limited, and may contain a small amount of inert gas such as nitrogen gas or carbon dioxide. The volume ratio of hydrogen to carbon monoxide is usually in the range of 1/10 to 10/1, and preferably the composition is in the range of 1/5 to 5/1. In the present invention, rhodium is present as a catalyst component. 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;
Complex compounds; salts such as rhodium trichloride, rhodium nitrate, rhodium acetate; oxides such as rhodium trihydroxide; trivalent complex compounds such as tris(acetylacetonato)rhodium; tetrarhodium dodecacarbonyl, hexalodium hexadecacarbonyl clusters such as rhodium tetracarbonyl anion, carbidehexarodium pentadecacarbonyl dianion, and other anion complexes. Furthermore, in the present invention, it is also possible to use a rhodium compound to which a phosphine compound that acts as a reaction accelerator is previously coordinated. Specific examples include RhH[P(i-Pr) ₃ ] ₃ , RhH
( _PEt3 ) ₄ , RhH( _PEt3 ) ₃ , {trans−Rh(CO)
(py) [P(i-Pr) ₃ ] ₂ }BPh ₄ , trans-RhH
(CO)[P ₍ c- _C6H11 ) ₃ ] ₂ , trans-RhH
(CO) [P(i-Pr) ₃ ] ₂ , Rh(CO)[P(n-
Bu) ₃ ] ₂ , RhH[P(t-Bu) ₃ ] ₂ , RhH[P
(c- _C6H11 ) ₃ ] ₂ , [Rh(CO) _3P (i- _Pr ) ₃ ]
₂ , Rh ₂ (CO) ₃ [P(i-Pr) ₃ ] ₃ , Rh ₂
(CO) ₄ [P(t-Bu) ₃ ] ₂ , Rh ₂ (CO) ₄ [P(c
−C ₆ H ₁₁ ) ₃ ] ₂ and the like. (In the above chemical formulas, i-Pr represents an isopropyl group, Et represents an ethyl group, py represents a pyridine group, Ph represents a phenyl group, c-C ₆ H ₁₁ represents a cyclohexyl group, and n-Bu represents an n- (butyl group and t-Bu represent t-butyl group, respectively.) The amount of rhodium used is as the concentration in the reaction solution.
It ranges from 0.0001 to 100 gram atoms, preferably from 0.001 to 10 gram atoms per liter of reaction solution. In the present invention, as a catalyst component, a trialkylphosphine which acts as a reaction accelerator and a general formula (): A compound having a 1,4-diazabutadiene skeleton represented by is present. Trialkylphosphine is thought to have the function of coordinating with rhodium, the main catalyst, and controlling its electronic state. Although the details of the control mechanism are not necessarily clear, it is assumed that, for example, the electron donating ability of trialkylphosphine plays an important role. In fact, the hydrogenation activity and selectivity to ethylene glycol of rhodium-phosphine catalyst systems vary widely depending on the type of phosphine. Therefore, in order to achieve a high level of ethylene glycol yield, it is necessary to use the general formula of phosphine.
PR ₁ R ₂ R ₃ (wherein R ₁ , R ₂ and R ₃ represent a primary alkyl group, a secondary alkyl group, a tertiary alkyl group or a cycloalkyl group, even if they are different from each other) It is particularly effective to use trialkylphosphines of the formula Specific examples of trialkylphosphines used in the present invention include trimethylphosphine, triethylphosphine, tri-n-propylphosphine, tri-n-butylphosphine, tri-n-octylphosphine, tri- iso-butylphosphine, tris(2-ethylhexyl)phosphine,
3 such as di-n-butyl-iso-butylphosphine
trialkylphosphine with primary alkyl groups; tri-iso-propylphosphine, tri-sec-butylphosphine, tri-tert-butylphosphine, tricyclopentylphosphine, tricyclohexylphosphine, di- iso-propyl-cyclopentylphosphine, di-iso-propyl-t-butylphosphine, di-t-butyl-
iso-bropylphosphine, di-t-butyl-sec
-butylphosphine, di-sec-butyl-iso-propylphosphine, di-iso-propyl-cyclohexylphosphine, di-t-butyl-cyclopentylphosphine, di-t-butyl-cyclohexylphosphine, di-sec -butyl-cyclohexylphosphine, dicyclopentyl-iso-propylphosphine, dicyclopentyl-t-butylphosphine, dicyclohexyl-iso-propylphosphine, diadamantyl-iso-propylphosphine, cyclopentyl-cyclohexyl-t
- Three secondary alkyl groups, tertiary alkyl groups, or cycloalkyl groups such as butylphosphine (hereinafter these are collectively referred to as "α-branched alkyl groups")
trialkylphosphine with; di-n-butyl-iso-propylphosphine, di-n-butyl-t-butylphosphine, di-n-butyl-cyclopentylphosphine, diethyl-iso-propylphosphine, diethyl - trialkylphosphine having two primary alkyl groups and one α-branched alkyl group, such as cyclopentylphosphine;
Di-iso-propyl-ethylphosphine, di-iso
-propyl-n-butylphosphine, di-t-butyl-methylphosphine, di-t-butyl-n-
Propylphosphine, di-t-butyl-n-butylphosphine, dicyclopentyl-ethylphosphine, dicyclopentyl-n-propylphosphine, dicyclopentyl-n-butylphosphine,
Dicyclohexyl-n-butylphosphine, dicyclohexyl-n-propylphosphine, diadamantyl-ethylphosphine, diadamantyl-
n-butylphosphine, dinorbornyl-ethylphosphine, dinorbornyl-n-butylphosphine, iso-propyl-t-butyl-n-butylphosphine, t-butyl-cyclohexyl-ethylphosphine, iso-propyl-cyclopentyl- Examples include trialkylphosphines having one primary alkyl group and two α-branched alkyl groups, such as n-octylphosphine. The amount of trialkylphosphine used above is
Usually 0.2 to 1 gram atom of rhodium
The amount is in the range of 1000 mol, preferably 0.5 to 100 mol, more preferably 0.8 to 10 mol. In addition, 1,4- represented by the above general formula ()
Among the compounds having a diazabutadiene skeleton, the general formula (): (In the formula, R ₁ , R ₂ , R ₃ and R ₄ are the same or different from each other and represent a hydrogen atom, an alkyl group, an aryl group, a heterocyclic group, a hydroxyl group, or an amino group. Also, R ₁ and R ₂ , It is more preferable to use a compound having a 1,4-diazabutadiene skeleton represented by R ₂ and R ₃ and R ₃ and R ₄ may be bonded to each other to form a ring. Specifically, N,N'-dimethyl-1,4-diazabutadiene N,N'-di-n-butyl-1,4-diazabutadiene N,N'-diisopropyl-1,4-diazabutadiene N,N'-di-t-butyl-1,4-diazabutadiene N,N'-dicyclohexyl-1,4-diazabutadiene N,N'-diisopropyl-2,3-dimethyl-
1,4-diazabutadiene N,N'-di-t-butyl-1,4-diazabutadiene N,N'-di-p-tolyl-1,4-diazabutadiene N,N'-bis(2,6-dimethylphenyl)-
1,4-diazabutadiene N,N'-bis(2,4,6-trimethylphenyl)-1,4-diazabutadiene N,N'-di-p-tolyl-2,3-dimethyl-
1,4-diazabutadiene 3,4,5,6,3',4',5',6'-octahydro-2,2'-dipyridyl 1,4-diazabutadienes such as; N-methylpicolinimine N-phenylpicolinimine N-methyl-2-methylimidazoleimine Monoheterocycle-containing α-diimines such as; dimethylglyoxime 1,2-benzoquinone dioxime Glyoxal dihydrazone Biacetyl dihydrazone 2-pyridine aldoxime Phenyl-2-pyridylketoxime Di-2-pyridylketoxime N-heteroatom-substituted α-diimines such as; 2,2'-bipyridine, 3,3'-dicarbomethoxy-2,2'-bipyridine, 6-methyl-2,2'-bipyridine, 6,6'-dimethyl-2,2'-bipyridine,6-butyl-2,2'-bipyridine,6-phenyl-2,2'-bipyridine,4,4'-dicarboxy-2,2'-bipyridine, 4,4 ′-diphenyl-
2,2'-bipyridine, 4-nitro-2,2'-bipyridine, 4,4'-dichloro-2,2'-bipyridine, 4,4'-di-t-butyl-2,2'-bipyridine, etc. 2,2'-bipyridines; 1,10-phenanthroline, 2,9-dimethyl, -1,10-phenanthroline, 2-methyl-1,10-phenanthroline, 5-amino-1, 10-phenanthroline,
4,7-dimethyl-1,10-phenanthroline,
1,10-phenanthrolines such as 3,4,7,8-tetramethyl-1,10-phenanthroline and 4,7-diphenyl-1,10-phenanthroline; 2,2'-biquinoline;2,2'-bipyrazine 2,2'-biimidazole 4,4',5,5'-tetracyano-2,2'-biimidazole 2,2'-bis(5-methyl-2-thiazoline) 1,4,5,8-tetraazaphenanthrene Bisheterocycles such as; 2-(2-pyridyl)quinoline Pyrido[2,3-e]benzothiazole 2-(2-pyridyl)imidazole 2-(2-pyridyl)benzimidazole 2-(2-pyridyl)imidazoline 2-(2-pyridyl)thiazole asymmetric bisheterocyclic compounds such as; 2,2′:6′,2″-terpyridine 2,6-di(2-quinolyl)pyridine N'-(2-pyridylmethyl)picolamidine picolinaldehyde azine 2-(2-pyridyl)-1,8-naphthyridine 2,7-di(2-pyridyl)-1,8-naphthyridine Examples include polydentate α-diimines such as . The amount of the above-mentioned compound having a 1,4-diazabutadiene skeleton used is usually 0.2 to 1000 mol, preferably 0.5 to 100 mol, per gram atom of rhodium.
mol, more preferably in the range of 0.8 to 10 mol. Although the invention can be carried out in the absence of a solvent, ie the reaction raw materials and catalyst components themselves serve as reaction medium, it is also possible to use a solvent. Examples of such solvents include diethyl ether,
Ethers such as anisole, tetrahydrofuran, ethylene glycol dimethyl ether, and dioxane; Ketones such as acetone, methyl ethyl ketone, and acetophenone; methanol, ethanol,
Alcohols such as n-butanol, benzyl alcohol, phenol, ethylene glycol, diethylene glycol; formic acid, acetic acid, propionic acid,
Carboxylic acids such as toluic acid; esters such as methyl acetate, n-butyl acetate, benzyl benzoate;
Aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and tetralin; Aliphatic hydrocarbons such as n-hexane, n-octane, and cyclohexane; Halogenated hydrocarbons such as dichloromethane, trichloroethane, and chlorobenzene; Nitro compounds such as nitromethane and nitrobenzene; triethylamine,
Tertiary amines such as tri-n-butylamine, benzyldimethylamine, pyridine, α-picoline, 2-hydroxypyridine; N,N-dimethylformamide, N,N-dimethylacetamide, N-
Carboxylic acid amides such as methylpyrrolidone; inorganic acid amides such as hexamethylphosphoric acid triamide, N,N,N',N'-tetraethylsulfamide;
N,N'-dimethylamidazolidone, N,N,
Ureas such as N',N'-tetramethylurea; Sulfones such as dimethylsulfone and tetramethylenesulfone; Sulfoxides such as dimethylsulfoxide and diphenylsulfoxide; Lactones such as γ-butyrolactone and ε-caprolactone; Tetraglyme , 18-crown-6, and other nitriles; acetonitrile, benzonitrile, and other nitriles; and dimethyl carbonate, ethylene carbonate, and other carbonate esters. Among the above solvents, aprotic polar solvents,
That is, it is preferable to use amines, amides, ureas, sulfones, sulfoxides, lactones, polyethers, nitriles, 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. As the reaction temperature, a condition of 100 to 300°C is usually adopted, but a more preferable temperature range is about 100 to 250°C. The reaction pressure used is 50Kg/ ^cm2 or higher, but usually 150Kg/cm2 or higher.
It is more common to carry out at ^around 600Kg/cm2. This method 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 catalyst liquid. [Examples] The present invention will be explained in more detail with reference to Examples below, 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-), which indicates the number of moles of product produced per unit reaction time.
atomRh・hr). Example 1 Tetrarhodium dodecacarbonyl [Rh ₄ (CO) ₁₂ ] containing 0.5 mg-atom of rhodium, tri-iso- was placed in a Hastelloy C autoclave with an internal volume of 35 c.c.
Propylphosphine 0.5 mmol, N,N'-di-t-
Butyl-1,4-diazabutadiene 0.5 mmol and N,N'-dimethylimidazolidone 10 as solvent
ml, then an equal volume mixed gas of carbon monoxide and hydrogen was injected at room temperature up to 300 kg/cm ² . The initial reaction pressure was 480 Kg/cm ² when the temperature of the autoclave was raised to 220°C. The reaction pressure was maintained in the range of 480 to 460 Kg/ ^cm2 by intermittently supplying an equal volume mixed gas of carbon monoxide and hydrogen, and the reaction pressure was maintained at 220℃.
A time reaction was performed. After the reaction, the autoclave was cooled, and the contents were taken out and analyzed by gas chromatography. As a result, 22.6 mol/g-atomRh・hr of ethylene glycol and 8.5 mol/g-atomRh・hr of methanol were produced. This was confirmed. Comparative Example 1 The reaction was carried out in the same manner as in Example 1, except that 0.5 mmol of N,N'-di-t-butyl-1,4-diazabutadiene was not added.
It was confirmed that 7.0 mol/g-atomRh·hr of ethylene glycol and 15.81 mol/g-atomRh·hr of methanol were produced. Examples 2 to 7 Example 1 except that 0.5 mmol of 1,4-diazabutadiene shown in Table 1 was used instead of N,N'-di-t-butyl-1,4-diazabutadiene.
The reaction was carried out in the same manner. The results are shown in Table-1.

[Table] Examples 9 to 17 Implemented except that 0.5 mmol of 1,4-diazabutadiene shown in Table 2 was used instead of N,N'-di-t-butyl-1,4-diazabutadiene. Example-1
The reaction was carried out in the same manner. The results are shown in Table-2.

【table】

[Table] Example 18 Except for changing the reaction temperature from 220°C to 230°C,
As a result of carrying out the reaction in the same manner as in Example-1,
It was confirmed that 26.7 mol/g-atomRh·hr of ethylene glycol and 13.1 mol/g-atomRh·hr of methanol were produced. Examples 19-20 The reaction was carried out in the same manner as in Example 1, except that the amount of N,N'-di-t-butyl-1,4-diazabutadiene used was changed as shown in Table 3. The results are shown in Table 3.

[Table] Examples 21 to 22 The reaction was carried out in the same manner as in Example 1, except that 0.5 mmol of trialkylphosphine shown in Table 4 was used instead of 0.5 mmol of tri-iso-propylphosphine. Summer. The results are shown in Table 4.

[Table] Examples 23-25 Instead of N,N'-dimethylimidazolidone,
Example except that 10ml of the solvent shown in Table 5 was used.
The reaction was carried out in the same manner as in 1. Table 5 shows the results.
Shown below.

[Table] Example 26 Acetylacetonatobis(carbonyl)rhodium, tri-iso- containing 1.2 mg-atom of rhodium in a Hastelloy C autoclave with an internal volume of 35 c.c.
Propylphosphine 1.2 mmol, N,N'-di-t-
1.2 mmol of butyl-1,4-diazabutadiene and 5 ml of N,N'-dimethylimidazolidone as solvent
After charging, an equal volume mixed gas of carbon monoxide and hydrogen was injected at room temperature up to 300 kg/cm ² . The initial reaction pressure was 475 Kg/cm ² when the temperature of the autoclave was raised to 230°C. The reaction pressure is increased by intermittently supplying an equal volume mixed gas of carbon monoxide and hydrogen.
The reaction was carried out at 230° C. for 1 hour while maintaining the temperature in the range of 500 to 480 Kg/cm ² . After the reaction, the autoclave was cooled, and the contents were taken out and analyzed by gas chromatography. As a result, 16.9 mol/g-atomRh・hr of ethylene glycol and 15.4 mol/g-atomRh・hr of methanol were produced. This was confirmed. Examples 27-37 Acetylacetonatobis(carbonyl)rhodium, tri-iso-propylphosphine, N,N'-
The reaction was carried out in the same manner as in Example 26, except that the amount of di-t-butyl-1,4-diazabutadiene used was changed as shown in Table 6. Display the results -
6.

[Table] Examples 38-40 Acetylacetonatobis(carbonyl)rhodium, tri-iso-propylphosphine and N,
Same as Example 26 except that the amount of N'-di-t-butyl-1,4-diazabutadiene used, the volume ratio of carbon monoxide and hydrogen, and the reaction temperature were changed as shown in Table 7. The reaction was carried out using The results are shown in Table-7.

[Table] [Effects of the Invention] 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. In a method for producing ethylene glycol by reacting carbon monoxide and hydrogen in a liquid phase in the presence of a rhodium catalyst, the presence of a compound having a trialkylphosphine and a 1,4-diazabutadiene skeleton in the reaction system. A method for producing ethylene glycol characterized by: