JPH0713067B2 - Method for producing furfuryl alcohol - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention provides a compound of formula (I) (In the formula, R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents an allyl group or a propargyl group).

<Prior Art> The furfuryl alcohols represented by the general formula (I) are useful intermediates for agricultural chemicals, pharmaceuticals, perfumes and the like.

Conventionally, as a method of obtaining an alcohol by a reaction of a carbonyl compound and a propargyl halide, (a) a Grignard reaction method, (b) a Rifomasky reaction method, (c) an organolithium compound method and the like are well known. There is.

Alternatively, a method of reacting a carbonyl compound and an allyl halide in the presence of zinc in (d) a tetrahydrofuran-water mixed solvent or (e) a tetrahydrofuran-saturated ammonium chloride aqueous solution mixed solvent [J. Or.
g. Chem., 50 910-912 (1985)].

<Problems to be Solved by the Invention> However, all of the above methods (a) to (c) require water-prohibiting conditions which are extremely disadvantageous industrially, and also involve a very large reaction heat, The methods (a) and (b) have a problem that they are extremely difficult to carry out on an industrial scale, such as via a rapid heat generation or an intermediate product having ignitability.

Further, when the methods (d) and (e) are applied to the reaction of furfural or 5-methylfurfural with an allyl halide, the reaction of the method (d) hardly progresses, and The method produces a large amount of tar-like substances, the yield of the desired furfuryl alcohols is very low (30% or less), and the reaction heat is large, and the raw material cost is increased by using ammonium chloride. Such as inviting
It is extremely unsatisfactory as an industrial method for producing furfuryl alcohols.

From the above, the present inventors have improved the above-mentioned drawbacks,
As a result of various investigations for producing the furfuryl alcohols represented by the general formula (I) industrially advantageously, as a result of reacting the furfural with a propargyl halide or an allyl halide under specific conditions, a mild reaction can be achieved. The inventors have found that the desired furfuryl alcohols can be obtained under the conditions and have reached the present invention.

<Means for Solving Problems> The present invention provides a compound represented by the general formula (II): (In the formula, R ₁ has the same meaning as described above) and a general formula (III) X—R ₂ (III) (wherein X represents a halogen atom and R ₂ has the same meaning as described above). In the presence of zinc, an acid, and an organic quaternary ammonium salt-based surfactant, water or water-
The present invention provides a method for producing furfuryl alcohols represented by the general formula (I), which comprises reacting in a mixed solvent of organic solvents.

In the present invention, furfural or 5-methylfurfural is used as the furfural represented by the general formula (III).

The halide represented by the general formula (III) is allyl halide or propargyl halide, and the bromine or chlorine atom is generally used as the halogen atom. The amount of such a halide used is preferably in the range of 1 to 3 times the mol of the raw material aldehyde.

In this reaction, the amount of zinc used is preferably in the range of 1 to 5 times the molar amount of the raw material furfural.

In the present invention, as the acid, a mineral acid such as hydrochloric acid, sulfuric acid, phosphoric acid or the like, or an organic acid such as acetic acid is used, and the amount thereof is preferably in the range of 0.01 to 10 times mol relative to the raw material furfural. , Is not particularly limited.

Further, as the organic quaternary ammonium salt-based surfactant, an organic quaternary ammonium salt known as a surfactant is used, and particularly preferred are tetraethylammonium bromide, tetraethylammonium chloride and tetraethylammonium bromide. Propylammonium, tetrapropylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium iodide, tetrabenzylammonium bromide, tetrabentylammonium chloride, benzyltriethylammonium chloride, benzyltripropylammonium chloride, odor And dodecyltrimethylammonium chloride and cetyltrimethylammonium chloride.

The amount of such organic quaternary ammonium salt used is preferably in the range of 0.005 to 1 times the molar amount of the raw material furfural. Of course, the reaction proceeds even if the amount exceeds 1 time, but the raw material cost increases, which is uneconomical.

The reaction is carried out in a water solvent or a water-organic solvent mixed system. The organic solvent is selected from aliphatic or aromatic hydrocarbons, ethers and amines, preferably n-hexane, toluene, xylene, tetrahydrofuran, diethyl ether and pyridine. The amount of the solvent used is usually 1 to 50 times the weight of the raw material furfural and 0 to 30 times the weight of the organic solvent, but it is not particularly limited.

The reaction temperature is generally selected in the range of 0 to 100 ° C, preferably 5 to 80 ° C.

The progress of the reaction is monitored by instrumental analysis such as gas chromatography, and the reaction ends when all the raw material furfurals have disappeared. The furfuryl alcohols are taken out from the reaction solution, for example, by separating the organic layer and then distilling the organic layer.

<Effects of the Invention> Thus, according to the method of the present invention, the desired furfuryl alcohols represented by the general formula (I) can be industrially easily obtained in a short time.

<Examples> Hereinafter, the present invention will be described with reference to Examples.

Example 1 A flask was charged with 44 g of 5-methylfurfural, 36.7 g of allyl chloride, 31.4 g of zinc powder, 28 g of tetrapentylammonium bromide, and 440 g of water, and then 45 ± 3 with stirring.
380 g of 5% hydrochloric acid was added over 3 hours while maintaining the temperature at 0 ° C., so that the pH in the reaction system was maintained at about 4.5. After the dropping was completed, the temperature was maintained for 30 minutes.

After the reaction was completed, the reaction solution was separated, and the organic layer was rectified under reduced pressure to obtain a fraction of 2- (1-hydroxy-3-butenyl) -5-methylfuran 34.2 g (content 99.6%). (Yield 56.0
%).

Example 2 After charging 44 g of 5-methylfurfural, 35.8 g of propargyl chloride, 52.3 g of zinc powder, 26 g of tetrabutylammonium bromide, 440 g of water and 88 g of toluene in a flask,
While maintaining the temperature at 35 ± 3 ° C. while stirring, 400 g of 5% hydrochloric acid was added dropwise over 3 hours so that the pH in the reaction system was maintained at about 4. After the dropping was completed, the temperature was maintained for 30 minutes.

After the reaction was completed, the reaction solution was separated, and the organic layer was rectified under reduced pressure to obtain 40.1 g of 2- (1-hydroxy-3-butynyl) -5-methylfuran fraction (content: 99.7%). (Yield 66.6
%).

Example 3 A flask was charged with 38.4 g of furfural, 57.1 g of propargyl bromide, 33 g of zinc powder, 26 g of benzyltripropylammonium chloride, 330 g of water and 33 g of tetrahydrofuran, and 59 g of acetic acid was added to 1 while maintaining the temperature at 35 ± 3 ° C. with stirring.
The solution was added dropwise over a period of time so as to maintain the pH in the reaction system at about 2. After the completion of dropping, the temperature was maintained for 2 hours.

After the reaction was completed, the reaction solution was separated, and the organic layer was rectified under reduced pressure to obtain 29.1 g (content 99.7%) of 2- (1-hydroxy-3-butynyl) -furan fraction (yield). 53.3%).

Example 4 Furfural 38.4 g and allyl chloride 36.7 in a flask.
g, zinc powder 52.3g, cetyltrimethylammonium chloride 28
g, 650 g of water and 65 g of tri-n-butylamine were charged, and then 4% of 430 g of 5% sulfuric acid was added while maintaining the temperature at 40 ± 3 ° C with stirring.
In order to maintain the pH in the reaction system at about 4.5 over time,
Dropped. After the dropping was completed, the temperature was maintained at the same temperature for 1 hour.

After the reaction was completed, the reaction solution was separated, and the organic layer was rectified under reduced pressure to obtain a fraction of 2- (1-hydroxy-3-butenyl) -furan 30.6 g (content 99.5%) (yield 55.1%).

Comparative Example 1 A flask was charged with 44 g of 5-methylfurfural, 36.7 g of allyl chloride, 31.4 g of zinc powder, 440 g of water and 44 g of tetrahydrofuran, and then the mixture was kept under stirring at 35 ± 3 ° C. for 7 hours.

After the reaction was completed, the reaction solution was separated and the organic layer was rectified under reduced pressure to obtain 1.1 g of 2- (1-hydroxy-3-butenyl) -5-methylfuran fraction (content: 99.0%). (Yield 1.8
%).

Comparative Example 2 In a flask, 44 g of 5-methylfurfural, 31.4 g of zinc powder,
After charging 97.1 g of ammonium chloride, 342.9 g of water and 88 g of tetrahydrofuran, while maintaining the temperature at 25 ± 3 ° C. with stirring, 36.7 g of allyl chloride was required for 1 hour and then kept at the same temperature for 2 hours after completion of dropping. .

After the reaction was completed, the reaction solution was separated and the organic layer was rectified under reduced pressure to obtain 14.8 g (content 98.7%) of 2- (1-hydroxy-3-butenyl) -5-methylfuran fraction. (Yield 24.0
%).

Claims (7)

[Claims] 1. A general formula (In the formula, R ₁ represents a hydrogen atom or a methyl group) and a general formula X—R ₂ (in the formula, X represents a halogen atom and R ₂ represents an allyl group or a propargyl group). The halogenated compound in the presence of zinc, an acid and an organic quaternary ammonium salt-based surfactant in water or water-
General formula characterized by reacting in a mixed solvent of organic solvents (In the formula, R ₁ and R ₂ have the same meanings as described above.) The method for producing furfuryl alcohols. 2. The production method according to claim 1, wherein the acid is a mineral acid. 3. The method according to claim 2, wherein the mineral acid is hydrochloric acid, sulfuric acid or phosphoric acid. 4. The method according to claim 1, wherein the acid is an organic acid. 5. The method according to claim 4, wherein the organic acid is acetic acid. 6. The method according to claim 1, wherein the organic solvent is an aliphatic hydrocarbon, an aromatic hydrocarbon, an ether or an amine. 7. An organic quaternary ammonium salt surfactant is tetraethylammonium bromide, tetraethylammonium chloride, tetrapropylammonium bromide, tetrapropylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, tetraiodide. Butylammonium, tetrapentylammonium bromide, tetrapentylammonium chloride, benzyltriethylammonium chloride, benzyltripropylammonium chloride, dodecyltrimethylammonium bromide or cetyltrimethylammonium chloride.
The manufacturing method according to item.