Synthesis method of 2-hydroxymethyl-5-methyl furan

Abstract

The synthesis method comprises the following steps: mixing 2-methylfuran with paraformaldehyde, diethyl ether and hydroquinone, adding a catalyst, immediately sealing a kettle opening, preventing gasification and leakage, carrying out temperature-controlled stirring reaction for a certain time under a certain pressure condition, carrying out pressure relief after cooling, discharging a reaction solution, neutralizing the reaction solution to be neutral by using a sodium carbonate solution, and carrying out reduced pressure distillation to obtain 2-hydroxymethyl-5-methylfuran. And standing for layering, removing the solvent and unreacted dimethyl furan, and rectifying to obtain the high-purity 2-hydroxymethyl-5-methyl furan. According to the method, the raw material ratio and the reaction temperature of the reaction are optimized at the same time, so that high yield of the reaction is achieved, safe and stable operation of the test is effectively guaranteed, and unexpected effects are achieved; the preparation process of the 3-hydroxymethyl-2-methylfuran is improved, so that the yield of the 3-hydroxymethyl-2-methylfuran is greatly improved, and the yield of the whole preparation process is further improved.

Description

Technical Field

[0001] The invention relates to the technical field of chemical synthesis, and in particular to a method for synthesizing 2-hydroxymethyl-5-methylfuran. Background Art

[0002] 2-Hydroxymethyl-5-methylfuran is a pharmaceutical intermediate with great application value, which can be used to prepare a series of compounds such as 2.5-dimethylfuran, 5-methylfurfural, 5-hydroxymethylfurfural, etc. At present, there is no report on the synthesis process of 2-hydroxymethyl-5-methylfuran in China. Summary of the invention

[0003] The object of the present invention is to provide a method for synthesizing 2-hydroxymethyl-5-methylfuran to solve the above-mentioned technical problems.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions: A method for synthesizing 2-hydroxymethyl-5-methylfuran comprises the following steps: mixing 2-methylfuran, paraformaldehyde, ether and hydroquinone, adding a catalyst, immediately sealing the kettle mouth to prevent gasification and leakage, reacting for a certain time under certain pressure conditions and temperature-controlled stirring, releasing the pressure after cooling, releasing the reaction liquid, neutralizing it to neutrality with a sodium carbonate solution, performing static stratification, removing the solvent and unreacted dimethylfuran, and then performing rectification to obtain high-purity 2-hydroxymethyl-5-methylfuran; the yield is 73% based on paraformaldehyde.

[0005] As a further embodiment of the present invention, the molar ratio of the 2-methylfuran to the paraformaldehyde is 1.0-2.5:1.

[0006] As a further solution of the present invention: the reaction pressure is 1.0-1.5 MPa.

[0007] As a further solution of the present invention: the stirring reaction temperature is 130-160°C, and the reaction time is 2.5-3.5h.

[0008] As a further embodiment of the present invention: the mass ratio of the 2-methylfuran to the diethyl ether is 1:3.

[0009] As a further solution of the present invention: the catalyst is zinc chloride, and the mass ratio of 2-methylfuran to zinc chloride is 7-10:1.

[0010] As a further embodiment of the present invention: the mass ratio of 2-methylfuran to hydroquinone is 200:1.

[0011] Reaction equation of the present invention is as follows:

[0012] The invention has the following beneficial effects: the invention adopts a synthesis method to synthesize 2-hydroxymethyl-5-methylfuran by using 2-methylfuran and paraformaldehyde, the conversion rate of 2-methylfuran and paraformaldehyde is high, the byproducts are small, the three wastes pollution is small, and the excess 2-methylfuran can be reused. The invention optimizes the raw material ratio and the reaction temperature of the reaction at the same time, so that the reaction obtains a high yield, and also effectively guarantees the safe and stable operation of the experiment, and obtains unexpected effects; the invention improves the preparation process of 3-hydroxymethyl-2-methylfuran, so that its yield is greatly improved, thereby improving the yield of the entire preparation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0014] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0015] Example 1

[0016] In a 2000ml medium-pressure reactor, 300g of 2-methylfuran, 120g of paraformaldehyde, 900g of ether and 1.5g of hydroquinone were added and mixed, and then 43g of zinc chloride was added. The reactor was immediately sealed to prevent gasification, and the temperature was raised to 150°C. At this time, the pressure was about 1.6MPa, and the reaction was stirred for 3h. After cooling, the pressure was released, the reaction liquid was discharged, and it was neutralized to neutrality with sodium carbonate solution, and then static stratification was performed, and the solvent and unreacted 2-methylfuran were removed from the organic phase, and then high-purity 2-hydroxymethyl-5-methylfuran was obtained by distillation. About 423g of 2-hydroxymethyl-5-methylfuran was obtained, with a content of 99.1% and a yield of 73%.

[0017] Under the conditions of Example 1, the amount of zinc chloride was changed, and it was found that even if the amount of catalyst was increased by 2 times, the yield of 2-hydroxymethyl-5-methylfuran changed little; when the amount of catalyst was reduced by 1 time, the yield of 2-hydroxymethyl-5-methylfuran decreased significantly. We speculate that the mass ratio of 2-methylfuran to zinc chloride is preferably 7-10:1.

[0018] Experimental method: 300g of 2-methylfuran, 120g of paraformaldehyde, 900g of ether and 1.5g of hydroquinone were added to a 2000ml medium-pressure reactor, and then 43g, 80g and 20g of zinc chloride were added respectively. The reactor mouth was immediately closed to prevent gasification, and the temperature was raised to 150°C. At this time, the pressure was about 1.6 MPa, and the reaction was stirred for 3h. After cooling, the pressure was released, the reaction liquid was released, and it was neutralized to neutrality with sodium carbonate solution. Then, it was statically layered, and the solvent and unreacted 2-methylfuran were removed from the organic phase, and then high-purity 2-hydroxymethyl-5-methylfuran was obtained by distillation.

[0019] Experimental Results

[0020] Under the conditions of Example 1, the amount of ether was changed, and it was found that the yield of 2-hydroxymethyl-5-methylfuran changed little when the amount of ether was increased by 1.2 times; the yield of 2-hydroxymethyl-5-methylfuran was sharply reduced when the amount of ether was reduced to 0.5 times; we speculate that the mass ratio of 2-methylfuran to ether is 1:3.

[0021] Experimental method: 300g of 2-methylfuran, 120g of paraformaldehyde, 900g, 1080g, 450g of ether and 1.5g of hydroquinone were added to a 2000ml medium-pressure reactor, and 43g, 80g and 20g of zinc chloride were added respectively. The reactor mouth was immediately closed to prevent gasification, and the temperature was raised to 150°C. At this time, the pressure was about 1.6 MPa, and the reaction was stirred for 3h. After cooling, the pressure was released, the reaction liquid was discharged, and it was neutralized to neutrality with sodium carbonate solution, and then static stratification was performed, the solvent and unreacted 2-methylfuran were removed from the organic phase, and then high-purity 2-hydroxymethyl-5-methylfuran was obtained by distillation.

[0022] Experimental Results

[0023] Example 4

[0024] Under the conditions of Example 1, the temperature and pressure (the pressure is about the saturated vapor pressure of ether at the corresponding temperature) were changed. It was found that when the temperature was lower than 130°C and the pressure was 8.5 MPa, the reaction rate was significantly slow. When the temperature was higher than 150°C and the pressure was higher than 1.6 MPa, the reaction rate was no longer significantly accelerated, the by-products increased, and the yield decreased. We speculate that the reaction temperature should be controlled at 130-150°C and the pressure should be controlled at 1.0-1.6 MPa.

[0025] Experimental method: Add 300g of 2-methylfuran, 120g of paraformaldehyde, 900g of ether and 1.5g of hydroquinone into a 2000ml medium-pressure reactor, mix them, add 43g of zinc chloride, immediately seal the reactor mouth to prevent gasification leakage, raise the temperature to 130℃, 140℃, 150℃ and 160℃ respectively, keep warm and stir to react for 3h, release the pressure after cooling, release the reaction liquid, neutralize it with sodium carbonate solution to neutrality, and then perform static stratification, remove the solvent and unreacted 2-methylfuran from the organic phase, and then distill to obtain high-purity 2-hydroxymethyl-5-methylfuran.

[0026] Experimental Results

[0027] Experimental Example 5 Under the conditions of Example 1, the reaction time was changed to 2h, 3h, and 4h, respectively. It was found that the reaction of polyformaldehyde was incomplete after 2h of reaction, and the conversion rate was significantly reduced; it was found that the side reactions increased significantly after 4h of reaction, and the product yield decreased; we speculate that it is appropriate to control the reaction time to 2.5-3h.

[0028] Experimental method: Add 300g of 2-methylfuran, 120g of paraformaldehyde, 900g of ether, and 1.5g of hydroquinone into a 2000ml medium-pressure reactor, mix them, add 43g of zinc chloride, immediately seal the reactor mouth to prevent gasification leakage, heat to 150℃, keep warm and react with stirring for 2h, 3h, and 4h respectively, release the pressure after cooling, release the reaction liquid, neutralize it with sodium carbonate solution to neutrality, and then perform static stratification to remove the solvent and unreacted 2-methylfuran from the organic phase, and then distill it to obtain high-purity 2-hydroxymethyl-5-methylfuran.

[0029] Experimental Results

[0030] The above is a preferred embodiment of the present invention. For ordinary technicians in this field, according to the teachings of the present invention, without departing from the principles and spirit of the present invention, changes, modifications, substitutions and variations made to the implementation methods are still within the scope of protection of the present invention.

Claims

1. A method for synthesizing 2-hydroxymethyl-5-methylfuran, characterized in that , including the following steps: mixing 2-methylfuran, paraformaldehyde, ether and hydroquinone, adding a catalyst, immediately closing the kettle mouth to prevent gasification and leakage, reacting for a certain time under certain pressure conditions and temperature control and stirring, releasing the pressure after cooling, releasing the reaction liquid, neutralizing it with sodium carbonate solution to neutrality, and then performing static stratification to remove the solvent and unreacted dimethylfuran, and then distilling to obtain high-purity 2-hydroxymethyl-5-methylfuran.

2. The synthesis method according to claim 1, characterized in that: The molar ratio of the 2-methylfuran to the paraformaldehyde is 1.0-2.5:

1.

3. The synthesis method according to claim 1, characterized in that: The reaction pressure is 1.0-1.5 MPa.

4. The synthesis method according to claim 1, characterized in that: The stirring reaction temperature is 130-160°C, and the reaction time is 2.5-3.5h.

5. The synthesis method according to claim 1, characterized in that: The mass ratio of the 2-methylfuran to diethyl ether is 1:

3.

6. The synthesis method according to claim 1, characterized in that: The catalyst is zinc chloride, and the mass ratio of 2-methylfuran to zinc chloride is 7-10:

1.

7. The synthesis method according to claim 1, characterized in that: The mass ratio of the 2-methylfuran to hydroquinone is 200:1.

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