JPH0437056B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for obtaining polyols such as ethylene glycol, glycerin, and erythritol from paraformaldehyde using a catalyst consisting of a ruthenium compound and an imidazolium salt. [Prior Art] There are no known examples of polyol production by reductive condensation reaction of formaldehyde. In addition, there is a formose reaction (the catalyst is calcium hydroxide (Ca(OH) ₂ ), etc.) to obtain carbohydrates from formaldehyde, but the selectivity is generally low and products with a wide range of carbon numbers are obtained (for example, T .Mizuno and AHWeiss, Adv.
(See Carbohydr.Chem.Biochem., 29, 173 (1974)). [Problems to be Solved by the Invention] An object of the present invention is to provide a novel method for producing polyol from paraformaldehyde in good yield. [Means for Solving the Problems] The present invention is characterized in that a catalyst system consisting of ruthenium, imidazolium salt, and optionally an organic amine is used in the synthesis reaction of polyol from paraformaldehyde. . That is, the present invention produces polyol from formaldehyde in the presence of hydrogen or in the coexistence of a mixed gas of hydrogen and carbon monoxide using a catalyst system consisting of ruthenium and imidazolium salts and, if necessary, an organic amine. This provides a new method. The ruthenium compounds used in the method of the present invention include halides, carboxylates, inorganic acid salts, oxides, compounds complexed with various organic ligands, and compounds complexed with various inorganic ligands. ,
Examples include ruthenium iodide, ruthenium acetate, ruthenium dioxide, Ru(acac) ₃ ,
( _{C5H5 ) 2Ru} , _Ru3 (CO) ₁₂ , etc. can be exemplified. The proportion of the ruthenium compound used is not particularly limited. As the imidazolium salt which is another catalyst component of the present invention, those represented by the following general formula [] can be mentioned. In the formula, R ₁ , R ₂ , R ₃ , and R ₄ may be the same or different, and include aliphatic groups such as alkyl groups such as methyl, ethyl, and propyl, and alkoxy groups such as methoxy and ethoxy, phenyl, and benzyl. arbitrarily selected from aromatic groups such as, and hydrogen (H).
Moreover, X represents a halogen atom such as I, Br, Cl. Other preferred examples include those represented by the following two general formulas [] and []. R ₁ , R ₂ and X in the formula have the same meanings as above. Moreover, n is an integer of 1 to 10. In the present invention, it is preferable to use an organic amine as another catalyst component together with the ruthenium compound and imidazolium salt. Examples of such organic amines include alkylamines such as triethylamine, alkanolamines such as triethanolamine, cyclohexylamines such as dicyclohexylamine, N-alkylpyrrolidines such as N-methylpyrrolidine, N-methylpyrrolidine, etc. N-alkylpiperidines, N,
N,N,N',N'-tetraalkyl-α,ω such as N,N',N'-tetramethylethylenediamine
-Alkanediamines, pyridines such as pyridine, alkylpyridine, 2-hydroxypyridine and 2-(β-hydroxyethyl)-pyridine, quinolines such as quinoline and isoquinoline, N,N
-Anilines such as dimethylaniline, 1,4-
Examples include diazabicycloamines such as diazabicyclo-[2.2.2.]octane and 1,8-diazabicyclo[5.4.0.]-7-undecene. The reaction of the present invention is usually carried out in the presence of a solvent. As the solvent, any organic solvent can be used as long as it is inert to the reaction. Specifically, dioxane, diethylene glycol dimethyl ether, 18
-Ethers such as Crown-6, methyl acetate,
Ethylene glycol diacetate, esters such as γ-butyrolactone, N,N-dimethylformamide, N,N-dimethylacetamide, N-
Amides such as methyl-2-pyrrolidone and N-benzylpyrrolidone, substituted ureas such as 1,3-dimethyl-2-imidazolidone, phenol, m-
Examples include phenols such as cresol and resorcinol, nitriles such as acetonitrile and benzonitrile, hydrocarbons such as hexane and cyclohexane, and aromatic hydrocarbons such as benzene, toluene, m-xylene, naphthalene and dodecylbenzene. be able to. The catalyst of the present invention can also be used in the coexistence of water. The amount of water used is arbitrary as long as it does not phase separate from the organic solvent. The method of the invention is carried out in the presence of hydrogen.
The hydrogen pressure at this time is 1 atm to 500 atm, preferably 10 to 200 atm. Further, the reaction temperature is room temperature to 300°C, preferably 50 to 200°C. The method of the present invention can also use a mixed gas of carbon monoxide and hydrogen instead of hydrogen. The hydrogen/carbon monoxide ratio in this case is chosen arbitrarily. The catalyst used in the method of the present invention can be prepared by separately adding a ruthenium compound, an imidazolium salt, and an organic amine if necessary to the reaction system; There is a method in which the organic amine is mixed in advance in a solvent and then introduced into the reaction system after preparation. In the present invention, the reaction is usually carried out under hydrogen pressure at a predetermined temperature (one-stage method), but after reacting once under nitrogen for a predetermined time, the gas is replaced with hydrogen, and then the reaction is carried out at the same temperature as in the one-stage method. (two-stage method). In this case, the nitrogen pressure in the reaction under nitrogen is arbitrary, and the reaction temperature is room temperature to 200°C, preferably 50 to 150°C. [Example] The present invention will be described in more detail below based on Examples. Note that the yields of the following products are all based on the raw material paraformaldehyde. The imidazolium salt used in each example has the following formula.

[Formula] 1a: R ₁ = Et, R ₂ = Me, X = Br 1b: R ₁ = Et, R ₂ = Et, X = Br 1c: R ₁ = Pr, R ₂ = Et, X = Br 1d: R ₁ = Me, R ₂ = Me, X = I 1e: R ₁ = Et, R ₂ = H, X = Br Example 1 Dodecacarbonyl triruthenium (Ru ₃
(CO) ₁₂ ) 0.1mg-atom, 3-ethyl-1-methylbenzimidazolium bromide (NMBI.EtBr.
3 mmol of triethylamine, 25 mmol of paraformaldehyde, 75 mmol of water, and 20 ml of dioxane were introduced, and the air in the autoclave was replaced with hydrogen gas. Next, the same gas was introduced to 100 atm, and the reaction was carried out at 150°C for 3 hours. After the reaction was completed, the autoclave was cooled to room temperature, the gas in the system was purged, the liquid reaction mixture was taken out, and after trimethylsilylation, it was quantified by gas chromatography, and the trimethylsilylated products of ethylene glycol, glycerin, and erythritol were 17.9, 16.1, and 5.5, respectively. % yield. Comparative Example 1 When the reaction was carried out in the same manner as in Example 1 except that (Ru ₃ (CO) ₁₂ ) was not used, glyceraldehyde was
Only 0.9% of the polyol was obtained, and the polyol was not produced at all. Comparative example 2 Example 1 except that NMBI.EtBr (1a) is not used
When the reaction was carried out in the same manner as above, _{no C2} to _C4 polyol was detected. Example 2 When the reaction was carried out in the same manner as in Example 1 except that triethylamine was not used, 6.0% and 3.3% of ethylene glycol and glycerin were obtained, respectively. Example 3 When the reaction was carried out in the same manner as in Example 1 except that water was not used, 10.2%, 4.8%, and 1.2% of ethylene glycol, glycerin, and erythritol were obtained, respectively. Example 4 The same catalyst solution as in Example 1 was heated with 100% nitrogen in advance.
After reacting at 60°C for 1 hour under atmospheric pressure, purging with nitrogen and filling with 100 atm of hydrogen instead, reacting at 150°C for 3 hours, ethylene glycol, glycerin, and erythritol were found to be 21.0, 18.6, and 18.6, respectively.
3.2% was obtained. Examples 5 to 8 Table 1 shows the results of experiments conducted in the same manner as in Example 1 by changing the types of imidazolium salts (1b to 1e in the above formula). EG, GLY, and Erith represent ethylene glycol, glycerin, and erythritol, respectively.

[Table] Comparative Examples 3 to 5 1-ethyl-4 instead of imidazolium salt
-dimethylaminopyridinium bromide 4,1
- The results using ethylquinolinium bromide 5 and calcium hydroxide are shown in Table 1. No product _C2 - _C4 polyol was observed. Examples 11-15 Triethanolamine, 1,4-diazabicyclo[2.2.2.]octane, isoquinoline, 2-(β-
The reaction was carried out in the same manner as in Example 1 except that hydroxyethyl)pyridine and N,N-dimethylaniline were used, and the results are shown in Table 2.

[Table] Aniline

Examples 16-18 N-methyl- instead of dioxane as solvent
2-pyrrolidone (NMP), acetonitrile ( _CH3CN ) and dimethylformamide (DMF)
Table 3 shows the results obtained in the same manner as in Example 3 except that .

[Table] Examples 19 and 20 The reaction was carried out in the same manner as in Example 1 except that the reaction temperature was different. The results are shown in Table 4.

〔Effect of the invention〕

According to the method of the present invention, polyols, especially _C2 to _C4 polyols, can be obtained in higher yield than in conventional formose reactions.

Claims (1)

[Claims] 1. A method for producing polyol from paraformaldehyde in the coexistence of hydrogen or a mixed gas of hydrogen and carbon monoxide using a catalyst comprising a ruthenium compound and an imidazolium salt. 2. The method for producing a polyol according to claim 1, characterized in that an organic amine is used in combination with a ruthenium compound and an imidazolium salt as a catalyst. 3. The manufacturing method according to claim 1 or 2, wherein the ruthenium compound is dodecacarbonyl triruthenium. 4 Imidazolium salt is the formula [] (In the formula, R ₁ , R ₂ , R ₃ , and R ₄ may be the same or different and represent an aliphatic group or hydrogen, and X represents a halogen atom.) A manufacturing method according to any one of claims 1 to 3. 5. The manufacturing method according to claim 2, wherein the organic amine is triethanolamine.