Method for enhancing hydration efficiency of 2, 3-dihydropyran

Abstract

The invention discloses a method for enhancing the hydration efficiency of 2, 3-dihydropyran. According to the present invention, 2, 3-dihydropyran and water are adopted as raw materials, alcohol chemicals are adopted as additives, and reaction is performed at a temperature of 80-160 DEG C and a pressure of 0.5-8 MPa in the presence or absence of an acid catalyst to produce the 2-hydroxytetrahydropyran and the derivative thereof. According to the method, the contact interface between the 2, 3-dihydropyran and the water raw material is promoted by using the additive, the addition reaction activity is improved, the hydration reaction efficiency is enhanced, the yield of a unit reaction device is improved, and the method has a good industrial application prospect.

Description

Technical Field

[0001] The invention relates to a method for enhancing the hydration efficiency of 2,3-dihydropyran, and belongs to the technical field of fine chemical industry. Background Art

[0002] 2-Hydroxytetrahydropyran and its derivatives 5-hydroxyvaleraldehyde, di-2-hydroxytetrahydropyran ether, etc. are raw materials for preparing 1,5-pentanediol, 1-hydroxy-pentylamine, and 1,5-pentanediamine. The invention of producing 1,5-pentanediol using tetrahydrofurfuryl alcohol as raw material disclosed in Chinese patent CN108368015 involves using 2,3-dihydropyran, a dehydration product of 1,5-pentanediol, as raw material, and reacting with raw water to obtain 2-hydroxytetrahydropyran through hydration reaction. The reaction requires a high molar ratio of water to 2,3-dihydropyran. The method for synthesizing 5-amino-1-pentanol disclosed in Chinese patent CN108947851 involves the hydration reaction of 2,3-dihydropyran to 2-hydroxytetrahydropyran. The reaction needs to be carried out under the protection of inert gas, which is not conducive to operation. In addition, 2,3-dihydropyran and water are directly used as raw materials for reaction. Due to the extremely low solubility of 2,3-dihydropyran in water, the above hydration reaction efficiency is low. Aiming at the problem that the reaction activity of 2,3-dihydropyran and water addition is low and thus the reaction efficiency is low, the present invention discloses a method for enhancing the reaction efficiency of 2,3-dihydropyran and water by using hydroxyl-containing alcohol chemicals as additives. By implementing the present invention, the output of a unit reaction device can be effectively improved. Summary of the invention

[0003] The present invention discloses a method for enhancing the hydration efficiency of 2,3-dihydropyran. The specific content of the invention is as follows:

[0004] A method for enhancing the hydration efficiency of 2,3-dihydropyran, comprising: using 2,3-dihydropyran and water as raw materials and an alcohol compound as an additive, adding 2,3-dihydropyran, water and the alcohol compound into a reactor, and producing one or more of 2-hydroxytetrahydropyran and its derivatives under the conditions of a reaction temperature of 80 to 160° C. and a reaction pressure of 0.5 to 8 MPa; wherein the molar ratio of the 2,3-dihydropyran to the water is 1:1 to 1:10, and the mass ratio of the alcohol compound to the 2,3-dihydropyran is 1:1 to 1:20.

[0005] In a preferred embodiment, the alcohol compound is one or more of methanol, ethanol, n-propanol, isopropanol, n-butanol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, furfuryl alcohol, tetrahydrofurfuryl alcohol, n-pentanol, 1,5-pentanediol, 1,2-pentanediol and 1,6-hexanediol.

[0006] In a preferred embodiment, the reactor is a reactor, a fixed bed or a tubular reactor.

[0007] In a preferred embodiment, the reaction temperature is 80-160°C, preferably 90-150°C, more preferably 100-140°C, most preferably 110-130°C.

[0008] In a preferred embodiment, the reaction pressure is 0.5 to 8 MPa, preferably 1 to 7 MPa, more preferably 1.5 to 6 MPa, and most preferably 2 to 6 MPa.

[0009] In a preferred embodiment, the molar ratio of the 2,3-dihydropyran to water is 1:1 to 1:10, preferably 1:2 to 1:9, more preferably 1:2 to 1:8, and most preferably 1:3 to 1:6.

[0010] In a preferred embodiment, the mass ratio of the alcohol additive to 2,3-dihydropyran is 1:1 to 1:20, preferably 1:2.5 to 1:10, more preferably 1:3 to 1:10, and most preferably 1:4 to 1:10.

[0011] In a preferred embodiment, the reaction is carried out in the presence or absence of an acidic catalyst.

[0012] The use of alcohol compound additives in the method promotes the contact interface between 2,3-dihydropyran and water raw materials, improves the activity of the addition reaction, strengthens the efficiency of the hydration reaction, and increases the output of a unit reaction device, which has good industrial application prospects. DETAILED DESCRIPTION

[0013] The method of the present invention is implemented according to the above steps, and is described in detail below through examples.

[0014] Example 1

[0015] Add 20 g of 2,3-dihydropyran, 12.9 g of deionized water, and 2 g of tetrahydrofurfuryl alcohol (the molar ratio of 2,3-dihydropyran to water is 1:3, and the mass ratio of tetrahydrofurfuryl alcohol to 2,3-dihydropyran is 1:10) to a 100 ml mechanically stirred reactor. Use N2 to replace the reactor three times, and then fill the reactor with 6 MPa N2. Heat the reactor to 110 ° C and stir at 600 rpm for 2 hours. After the reaction is completed, cool to room temperature and analyze and calculate the reaction mixture. The conversion rate of 2,3-dihydropyran is 87%, and the total selectivity of 2-hydroxytetrahydropyran, 5-hydroxyvaleraldehyde and di-2-tetrahydropyran ether is 96%.

[0016] Example 2

[0017] Except that the reaction temperature was changed to 130° C., other conditions (and processes, the same below) were the same as in Example 1. The conversion rate of 2,3-dihydropyran was 98%, and the total selectivity of 2-hydroxytetrahydropyran, 5-hydroxyvaleraldehyde and di-2-tetrahydropyranyl ether was 94%.

[0018] Example 3

[0019] Except that the pressure of nitrogen filling the reactor was changed to 2 MPa, other conditions were the same as those in Example 1. The conversion rate of 2,3-dihydropyran was 85%, and the total selectivity of 2-hydroxytetrahydropyran, 5-hydroxyvaleraldehyde and di-2-tetrahydropyranyl ether was 97%.

[0020] Example 4

[0021] Except that the mass of tetrahydrofurfuryl alcohol was changed to 5 g (the mass ratio of tetrahydrofurfuryl alcohol to 2,3-dihydropyran was 1:4), other conditions were the same as those in Example 1. The conversion rate of 2,3-dihydropyran was 99%, and the total selectivity of 2-hydroxytetrahydropyran, 5-hydroxyvaleraldehyde and di-2-tetrahydropyranyl ether was 95%.

[0022] Example 5

[0023] Except that the mass of tetrahydrofurfuryl alcohol was changed to 3.3 g (the mass ratio of tetrahydrofurfuryl alcohol to 2,3-dihydropyran was 1:6), other conditions were the same as those in Example 1. The conversion rate of 2,3-dihydropyran was 94%, and the total selectivity of 2-hydroxytetrahydropyran, 5-hydroxyvaleraldehyde and di-2-tetrahydropyranyl ether was 95%.

[0024] Example 6

[0025] Except that tetrahydrofurfuryl alcohol was replaced by methanol, other conditions were the same as those in Example 1. The conversion rate of 2,3-dihydropyran was 90%, and the total selectivity of 2-hydroxytetrahydropyran, 5-hydroxyvaleraldehyde and di-2-tetrahydropyranyl ether was 94%.

[0026] Example 7

[0027] Except that tetrahydrofurfuryl alcohol was replaced by isopropanol, other conditions were the same as those in Example 1. The conversion rate of 2,3-dihydropyran was 88%, and the total selectivity of 2-hydroxytetrahydropyran, 5-hydroxyvaleraldehyde and di-2-tetrahydropyranyl ether was 96%.

[0028] Example 8

[0029] Except that tetrahydrofurfuryl alcohol was replaced by 1,4-butanediol, other conditions were the same as those in Example 1. The conversion rate of 2,3-dihydropyran was 91%, and the total selectivity of 2-hydroxytetrahydropyran, 5-hydroxyvaleraldehyde and di-2-tetrahydropyranyl ether was 97%.

[0030] Example 9

[0031] Except that tetrahydrofurfuryl alcohol was replaced by 1,5-pentanediol, other conditions were the same as those in Example 1. The conversion rate of 2,3-dihydropyran was 87%, and the total selectivity of 2-hydroxytetrahydropyran, 5-hydroxyvaleraldehyde and di-2-tetrahydropyranyl ether was 95%.

[0032] Example 10

[0033] A tubular reactor with an inner diameter of 10 mm and a length of 500 mm was used, and the reactor was heated by a jacketed heat transfer oil. N2 was filled into the reactor, and the N2 valve was closed when the pressure reached 4 MPa. A mixed solution of 2,3-dihydropyran and tetrahydrofurfuryl alcohol (the mass ratio of tetrahydrofurfuryl alcohol to 2,3-dihydropyran was 1 / 5) was pumped into the inlet of the tubular reactor at a rate of 0.3 ml / min through a constant flow pump, and deionized water was pumped into the inlet of the tubular reactor at a rate of 0.35 ml / min. The system pressure was controlled to 4 MPa by a back pressure valve. The reaction was carried out at 120°C, and after 4 hours of reaction, sampling was analyzed and calculated. The conversion rate of 2,3-dihydropyran was 93%, and the total selectivity of 2-hydroxytetrahydropyran, 5-hydroxyvaleraldehyde and di-2-tetrahydropyran ether was 96%.

[0034] Comparative Example 1

[0035] Add 20 g of 2,3-dihydropyran and 12.9 g of deionized water (the molar ratio of 2,3-dihydropyran to water is 1:3) to a 100 ml mechanically stirred reactor. Use N2 to replace the reactor three times, and then fill the reactor with 6 MPa N2. Heat the reactor to 110 ° C and stir at 600 rpm for 2 hours. After the reaction is completed, cool to room temperature and analyze and calculate the reaction mixture. The conversion rate of 2,3-dihydropyran is 51%, and the total selectivity of 2-hydroxytetrahydropyran, 5-hydroxyvaleraldehyde and di-2-tetrahydropyran ether is 93%.

[0036] Comparative Example 2

[0037] A tubular reactor with an inner diameter of 10 mm and a length of 500 mm was used, and the reactor was heated by a jacketed heat transfer oil. N2 was filled into the reactor, and the N2 valve was closed when the pressure reached 4 MPa. 2,3-Dihydropyran was pumped into the inlet of the tubular reactor at a rate of 0.3 ml / min through a constant flow pump, and deionized water was pumped into the inlet of the tubular reactor at a rate of 0.35 ml / min. The system pressure was controlled to 4 MPa by a back pressure valve. The reaction was carried out at 120°C, and after 4 hours of reaction, sampling was performed for analysis and calculation. The conversion rate of 2,3-dihydropyran was 60%, and the total selectivity of 2-hydroxytetrahydropyran, 5-hydroxyvaleraldehyde and di-2-tetrahydropyran ether was 94%.

[0038] It can be seen from Example 1 and Comparative Example 1, and Example 10 and Comparative Example 2 that the use of alcohol compound additives can greatly increase the conversion rate of 2,3-dihydropyran in the reaction and improve the reaction efficiency. It can be seen from Examples 1-10 that the method provided by the present invention can achieve a high conversion rate reaction during the reaction of 2,3-dihydropyran and water. The present invention greatly improves the conversion rate of the hydration reaction of 2,3-dihydropyran by selecting alcohol compounds as additives, and the reaction conditions are mild and the operating window is large, the process is simple, and it is applicable to a variety of reactors, easy to scale up, and has considerable industrial application prospects.

Claims

1. A method for enhancing the hydration efficiency of 2,3-dihydropyran, characterized in that: With 2,3-dihydropyran and water as raw materials and alcohol compounds as additives, 2,3-dihydropyran, water and alcohol compounds are added into a reactor, and one or more of 2-hydroxytetrahydropyran and its derivatives are produced under the conditions of a reaction temperature of 80-160°C and a reaction pressure of 0.5-8MPa; wherein the molar ratio of 2,3-dihydropyran to water is 1:1-1:10, and the mass ratio of the alcohol compounds to 2,3-dihydropyran is 1:1-1:

20.

2. The method according to claim 1, characterized in that: The alcohol compound is one or more of methanol, ethanol, n-propanol, isopropanol, n-butanol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, furfuryl alcohol, tetrahydrofurfuryl alcohol, n-pentanol, 1,5-pentanediol, 1,2-pentanediol and 1,6-hexanediol.

3. The method according to claim 1, characterized in that: The reactor is a reactor, a fixed bed or a tubular reactor.

4. The method according to claim 1, characterized in that: The reaction temperature is 80-160°C, preferably 90-150°C, more preferably 100-140°C, most preferably 110-130°C.

5. The method according to claim 1, characterized in that: The reaction pressure is 0.5 to 8 MPa, preferably 1 to 7 MPa, more preferably 1.5 to 6 MPa, and most preferably 2 to 6 MPa.

6. The method according to claim 1, characterized in that: The molar ratio of the 2,3-dihydropyran to water is 1:1 to 1:10, preferably 1:2 to 1:9, more preferably 1:2 to 1:8, and most preferably 1:3 to 1:

6.

7. The method according to claim 1, characterized in that: The mass ratio of the alcohol additive to 2,3-dihydropyran is 1:1 to 1:20, preferably 1:2.5 to 1:10, more preferably 1:3 to 1:10, and most preferably 1:4 to 1:

10.

8. The method according to claim 1, characterized in that: The reaction is carried out in the presence or absence of an acidic catalyst.