A process for the photo-catalytic metathesis of homoallyl alcohols

Abstract

The application discloses a photo-catalytic transposition isomerization process of isoalkenyl alkyne alcohol, which comprises the following steps: under the conditions of an initiator and blue light, isoalkenyl alkyne alcohol shown in formula (I) is subjected to transposition isomerization reaction in a mixed system of water and an organic solvent, so as to obtain E-pent-2-ene-4-alkyn-1-ol shown in formula (II) and Z-pent-2-ene-4-alkyn-1-ol shown in formula (III). The method uses LED blue light irradiation, improves photoelectric efficiency of the transposition isomerization process, reduces the amount of acid, and greatly improves the safety of the process route.

Description

Technical Field

[0001] This invention belongs to the field of vitamin intermediate preparation, specifically relating to a process for photoisomerizing isoenkynol into cis-enkynol and trans-enkynol. Background Technology

[0002] E-enynol (II) and Z-enynol (III), the trans isomers of enynol, are two important chemical intermediates. E-enynol, the trans isomer, can be used to synthesize astaxanthin and canthaxanthin, while Z-enynol, the cis isomer, can be used to synthesize vitamin A. E-enynol and Z-enynol are generally obtained through the isomerization reaction of enynol (I), and the product obtained is a mixture of the two isomers. In the synthesis of vitamin A, to ensure product quality, it is necessary to control the selectivity of the transposition reaction as much as possible to obtain as many Z-isomers as possible.

[0003]

[0004] CN 101605748 A discloses an isomerization process for pent-1-en-3-ol. This method, in a multiphase system containing an aqueous phase and an organic solvent phase, uses hydroquinone as an initiator in the presence of an acid catalyst to isomerize pent-1-en-3-ol to obtain a mixture of Z-pent-2-en-1-ol and E-pent-2-en-1-ol. The isomerization reaction has high conversion and overall yield, but low selectivity and a low proportion of the Z-isomer. The ratio of Z-pent-2-en-1-ol to E-pent-2-en-1-ol is approximately 75:15, making it unsuitable for the synthesis of vitamin A. Furthermore, this method requires holding at 50–60°C for 1–25 hours, while the enynyl alcohol isomer is prone to coking and posing a safety hazard under high temperature and acid conditions. Summary of the Invention

[0005] This invention provides a photocatalytic transisomerization process for isoenkynols, which improves the selectivity of the Z isomer in the product, while reducing the reaction temperature and preventing coking.

[0006] The technical solution of the present invention is as follows:

[0007] A photocatalytic transisomerization process for isoenkynols includes:

[0008] Under initiator and light conditions, the isoenynyl alcohol represented by formula (I) undergoes a transisomerization reaction in a mixed system of water and organic solvent to obtain E-pent-2-en-4-yn-1-ol represented by formula (II) and Z-pent-2-en-4-yn-1-ol represented by formula (III).

[0009]

[0010] In equations (I) to (III), R 1 R is hydrogen, alkyl, or aryl. 2 It is alkyl or aryl;

[0011] The initiator is a protic acid;

[0012] The wavelength of the illumination is 365–510 nm.

[0013] In this invention, by applying light of a specific wavelength to the reaction system and in the presence of an initiator, the proportion of the Z-isomer is increased, making it more suitable for the production of vitamin A. At the same time, the temperature of the isoenynyl alcohol transisomerization reaction can be lowered, reducing the possibility of coking in the reaction system and making industrial applications safer.

[0014] The specific feeding method of this invention is as follows:

[0015] The isoenkynol is dissolved in an organic solvent to form an isoenkynol solution, and the initiator is dissolved in water to form an initiator solution. The solutions are then mixed and reacted under the light conditions.

[0016] In this invention, an initiator is essential under light source irradiation. Preferably, the initiator is sulfuric acid, acetic acid, or an aqueous solution thereof.

[0017] Preferably, the concentration of the initiator is 5 wt% to 50 wt%, and more preferably 5 wt% to 40 wt% for better initiation effect, and even more preferably 10 wt% to 40 wt%.

[0018] In this invention, the illumination uses an LED light source. Typically, the LED light source has a main emission wavelength in the range of at least 365nm to 510nm, preferably in the range of 405nm to 480nm, and more preferably in the range of 450nm to 480nm. Within this wavelength range, it is beneficial to increase the proportion of the Z isomer. Furthermore, the LED light source used in this invention can be a surface light source.

[0019] In this invention, isoenkynol is exposed to LED light and generates heat. Currently, it is known that the dissipated heat has no impact on the isomerization process.

[0020] In this invention, the optical power of the LED light source has a certain influence on the reaction, and its output power is around 10 mW / cm². 2 ~100mw / cm 2 30-50 mw / cm is preferred. 2 .

[0021] As a preferred option, R 1It is hydrogen, C1-C6 alkyl, or C6-C 10 Aryl, R 2 It is a C1-C6 alkyl group or a C6-C6 alkyl group. 10 Aryl; as the optimal choice, R 1 It is hydrogen, R 2 If it is methyl, then isoenynol is 3-methyl-1-penten-4-yn-3-ol as shown in formula (Ⅳ), and the E-isomer and Z-isomer of isoenynol are E-3-methylpenten-2-en-4-yn-1-ol as shown in formula (Ⅴ) and Z-3-methylpenten-2-en-4-yn-1-ol as shown in formula (Ⅵ).

[0022]

[0023]

[0024]

[0025] In this invention, the volume ratio of the initiator solution to the enynyl alcohol solution is at least 1 / 20, more preferably at least 1 / 10. To achieve a better conversion rate, the volume ratio of the initiator to the enynyl alcohol solution is at most 1 / 1, more preferably at most 1 / 2, and most preferably at most 1 / 5.

[0026] Preferably, the transisomerization reaction must be carried out in a solution of enynyl alcohol, and an organic solvent is essential. A polar organic solvent is more preferred. More preferably, the organic solvent is an alcohol, nitrile, aromatic hydrocarbon, or a mixture thereof. The nitrile can be aliphatic or aromatic, preferably containing 1 to 7 carbon atoms. The aromatic hydrocarbon can be benzene or toluene. The most preferred organic solvent is acetonitrile or toluene or a mixture thereof. The enynyl alcohol and the initiator can be a homogeneous solution or a heterogeneous solvent.

[0027] In this invention, the content of the isoenkynol is 1 wt% to 50 wt%, preferably 10 wt% to 40 wt%, more preferably 15 wt% to 30 wt%, and most preferably 15 wt% to 20 wt%.

[0028] In this invention, pressure has no effect on the conversion of enynols, and it is preferred to carry out the conversion under normal pressure.

[0029] In this invention, the light can be emitted in an air atmosphere or in a nitrogen atmosphere, with an air atmosphere being preferred.

[0030] In this invention, the reaction temperature is crucial. The reaction is preferably carried out under air conditions and normal pressure, preferably in the temperature range of 0°C to 60°C, more preferably in the range of 0°C to 30°C, and most preferably in the range of 10°C to 30°C. Lower temperatures can effectively prevent coking and are more conducive to the selective formation of the Z isomer.

[0031] In this invention, the LED light source irradiation time is in the range of 1 hour to 8 hours, preferably in the range of 2 hours to 6 hours, and most preferably in the range of 2 hours to 4 hours.

[0032] All known photoreactors are suitable for photocatalytic isoenynyl alcohol transisomerization reactions, and both batch and continuous reactors are applicable.

[0033] In this invention, the isomer mixture after light exposure can be separated into E-enynol and Z-enynol and aqueous solution through stratification, and E-enynol and Z-enynol are purified by distillation.

[0034] Compared with the prior art, the beneficial effects of the present invention are reflected in:

[0035] (1) The present invention uses specific light conditions and initiators to realize the transisomerization reaction of isoenkynol, which increases the proportion of Z-enkynol and is more conducive to the synthesis of vitamin A.

[0036] (2) The photocatalytic conditions of the present invention are beneficial to reducing the reaction temperature, avoiding coking of the reaction system, and making the reaction process safer. Detailed Implementation

[0037] The starting materials were: isoenkynol, purity >99%, sulfuric acid, and acetic acid initiator, which were commercially available and did not require further purification.

[0038] The mixture was analyzed by gas chromatography. 1-Hexanol was used as an internal standard to assess the yield of enyneols. Z-enyneols and E-enyneols were confirmed by retention time comparison with standards.

[0039] Gas chromatography conditions: OV-17 capillary column, 30m*0.32mm*0.33μm, detector: 230℃, column temperature: 110℃, injector temperature: 200℃, run time: 5min, injection volume: 0.22ul (using a 1ul microsyringe).

[0040] Example 1

[0041] Isoenkynol (Formula IV) was dissolved in toluene to obtain a 20 wt% solution. A 30 wt% sulfuric acid solution was added as an initiator to the toluene solution of isoenkynol, with a volume ratio of sulfuric acid to isoenkynol solution of 1:5. The resulting solution was then added to a beaker. A 470 nm blue LED lamp with a light intensity of 30 mW / cm² was placed 10 cm away from the outside. 2The beaker contained circulating coolant, and the temperature was controlled at 30°C. Under continuous stirring, the toluene solution was irradiated, causing isoenyne alcohol to convert to Z-enyne alcohol and E-enyne alcohol. After 2 hours of irradiation, the irradiation was stopped, and the conversion rate, yield, and Z-isomer / E-isomer ratio of isoenyne alcohol were determined by gas chromatography. The isoenyne alcohol conversion rate was 97.1%, the yield was 86.5%, and the Z-enyne alcohol:E-enyne alcohol ratio was 84:16. After the reaction, the layers were separated. The oil layer was a toluene solution of cis / trans-enyne alcohol, and the aqueous layer (sulfuric acid layer) was reused for the next batch. Excess toluene in the oil layer was removed by scraping, and the remaining toluene was removed by distillation. Further distillation yielded cis / trans-enyne alcohol. The enyne alcohol yield was >85%, and the Z-enyne alcohol:E-enyne alcohol ratio was 85:15.

[0042] Example 2

[0043] Isoenkynol (Formula IV) was dissolved in toluene to produce a 20 wt% solution. A 30 wt% sulfuric acid solution was added as an initiator to the toluene solution of isoenkynol, with a volume ratio of sulfuric acid to isoenkynol solution of 1:5. The resulting solution was then added to a beaker. A 470 nm blue LED lamp with a light intensity of 30 mW / cm² was placed 10 cm away from the outside. 2 The beaker contained circulating coolant, and the temperature was controlled at 30°C. Under continuous stirring, the toluene solution was irradiated, causing isoenyne alcohol to convert to Z-enyne alcohol and E-enyne alcohol. After 4 hours of irradiation, the irradiation was stopped, and the conversion rate, yield, and Z-isomer / E-isomer ratio of isoenyne alcohol were determined by gas chromatography. The isoenyne alcohol conversion rate was 99.6%, the yield was 80.9%, and the Z-enyne alcohol:E-enyne alcohol ratio was 97:3. After the reaction, the layers were separated. The oil layer was a toluene solution of cis / trans-enyne alcohol, and the aqueous layer (sulfuric acid layer) was reused for the next batch. Excess toluene in the oil layer was removed by scraping, and the remaining toluene was removed by distillation. Further distillation yielded cis / trans-enyne alcohol. The enyne alcohol yield was >78%, and the Z-enyne alcohol:E-enyne alcohol ratio was 97:3.

[0044] Example 3

[0045] Isoenkynol (Formula IV) was dissolved in toluene to produce a 20 wt% solution. A 30 wt% sulfuric acid solution was added as an initiator to the toluene solution of isoenkynol, with a volume ratio of sulfuric acid to isoenkynol solution of 1:5. The resulting solution was then added to a beaker. A 470 nm blue LED lamp with a light intensity of 30 mW / cm² was placed 10 cm away from the outside. 2The beaker contained circulating cooling liquid, and the temperature was controlled at 30°C. Under continuous stirring, the toluene solution was irradiated, causing isoenyne alcohol to convert into Z-enyne alcohol and E-enyne alcohol. After 6 hours of irradiation, the irradiation was stopped, and the conversion rate of isoenyne alcohol, the yield of enyne alcohol, and the ratio of Z-isomer to E-isomer were determined by gas chromatography. The conversion rate of isoenyne alcohol was 99.9%, the yield of enyne alcohol was 78.3%, and the Z-enyne alcohol:E-enyne alcohol ratio was 98:2.

[0046] Comparative Example 1

[0047] Isoenkynol (Formula IV) was dissolved in toluene to produce a 20 wt% solution. A 30 wt% sulfuric acid solution was added as an initiator to the toluene solution of isoenkynol, with a volume ratio of sulfuric acid to isoenkynol solution of 1:5. The resulting solution was then added to a beaker. A 254 nm ultraviolet lamp with a light intensity of 10 mW / cm² was placed 10 cm away from the outside. 2 The beaker contained a circulating coolant, and the temperature was controlled at 30°C. Under continuous stirring and irradiation of the toluene solution, isoenyne alcohol was converted into Z-enyne alcohol and E-enyne alcohol. After 4 hours of irradiation, the irradiation was stopped, and the conversion rate of isoenyne alcohol, the yield of enyne alcohol, and the ratio of Z-isomer to E-isomer were determined by gas chromatography. The conversion rate of isoenyne alcohol was 95.2%, the yield of enyne alcohol was 30.9%, and the Z-enyne alcohol:E-enyne alcohol ratio was 75:25. Significant coking was observed in the reaction.

[0048] The comparison shows that when using 254nm illumination conditions, the conversion rate decreases, the yield decreases, and the selectivity decreases.

[0049] Comparative Example 2

[0050] Isoenkynol (Formula IV) was dissolved in toluene to produce a 20 wt% solution. A 30 wt% sulfuric acid solution was added as an initiator to the toluene solution of isoenkynol, with a volume ratio of sulfuric acid to isoenkynol solution of 1:5. The resulting solution was then added to a beaker. A 310 nm ultraviolet lamp with a light intensity of 10 mW / cm² was placed 10 cm away from the outside. 2 The beaker contained a circulating coolant, and the temperature was controlled at 30°C. Under continuous stirring and irradiation of the toluene solution, isoenyne alcohol was converted into Z-enyne alcohol and E-enyne alcohol. After 4 hours of irradiation, the irradiation was stopped, and the conversion rate of isoenyne alcohol, the yield of enyne alcohol, and the ratio of Z-isomer to E-isomer were determined by gas chromatography. The conversion rate of isoenyne alcohol was 92.6%, the yield of enyne alcohol was 44.9%, and the Z-enyne alcohol:E-enyne alcohol ratio was 80:20. The reaction produced slight coking.

[0051] Comparative Example 3

[0052] Isoenkynol (Formula IV) was dissolved in toluene to produce a 20 wt% solution. A 30 wt% sulfuric acid solution was added as an initiator to the toluene solution of isoenkynol, with a volume ratio of sulfuric acid to isoenkynol solution of 1:5. The resulting solution was then added to a beaker. A 520 nm LED light with a light intensity of 30 mW / cm² was placed 10 cm away from the outside. 2 The beaker contained circulating coolant, and the temperature was controlled at 30°C. Under continuous stirring, the toluene solution was irradiated, causing isoenyne alcohol to convert into Z-enyne alcohol and E-enyne alcohol. After 4 hours of irradiation, the irradiation was stopped, and the conversion rate of isoenyne alcohol, the yield of enyne alcohol, and the ratio of Z-isomer to E-isomer were determined by gas chromatography. The conversion rate of isoenyne alcohol was 78.5%, the yield of enyne alcohol was 50.9%, and the Z-enyne alcohol:E-enyne alcohol ratio was 82:18.

[0053] The comparison shows that when using 520nm illumination conditions, the conversion rate decreases, the yield decreases, and the selectivity decreases.

[0054] Comparative Example 4

[0055] Isoenkynol (Formula IV) was dissolved in toluene to produce a 20 wt% solution. A 30 wt% sulfuric acid solution was added as an initiator to the toluene solution of isoenkynol, with a sulfuric acid to isoenkynol solution volume ratio of 1:5. The resulting solution was then added to a beaker. A white LED light with an illuminance of 100 mW / cm² was placed 10 cm away from the outside. 2 The beaker contained circulating coolant, and the temperature was controlled at 30°C. Under continuous stirring, the toluene solution was irradiated, causing isoenyne alcohol to convert into Z-enyne alcohol and E-enyne alcohol. After 4 hours of irradiation, the irradiation was stopped, and the conversion rate of isoenyne alcohol, the yield of enyne alcohol, and the ratio of Z-isomer to E-isomer were determined by gas chromatography. The conversion rate of isoenyne alcohol was 23.5%, the yield of enyne alcohol was 17.7%, and the Z-enyne alcohol:E-enyne alcohol ratio was 79:21.

[0056] The comparative example shows that when white light irradiation is used, the conversion rate decreases, the yield decreases, and the selectivity decreases.

[0057] Example 4

[0058] Isoenkynol (Formula IV) was dissolved in toluene to produce a 20 wt% solution. A 30 wt% sulfuric acid solution was added as an initiator to the toluene solution of isoenkynol, with a volume ratio of sulfuric acid to isoenkynol solution of 1:5. The resulting solution was added to a beaker. A 470 nm LED blue light was placed 10 cm away from the outside, and the beaker contained circulating coolant, with the temperature controlled at 20 °C. The toluene solution was irradiated with continuous stirring, causing the isoenkynol to convert to Z-enkynol and E-enkynol. After 4 hours of irradiation, the irradiation was stopped, and the conversion rate of isoenkynol, the yield of enkynol, and the ratio of Z-isomer to E-isomer were determined by gas chromatography. The conversion rate of isoenkynol was 91.6%, the yield of enkynol was 80.0%, and the Z-enkynol:E-enkynol ratio was 92:8. No coking was observed in the reaction.

[0059] Comparative Example 5

[0060] Isoenkynol (Formula IV) was dissolved in toluene to produce a 20 wt% solution. A 30 wt% sulfuric acid solution was added as an initiator to the toluene solution of isoenkynol, with a volume ratio of sulfuric acid to isoenkynol solution of 1:5. The resulting solution was added to a beaker. A 470 nm LED blue light was placed 10 cm away from the outside, and the beaker contained circulating coolant, with the temperature controlled at 40 °C. The toluene solution was irradiated with continuous stirring, causing the isoenkynol to convert to Z-enkynol and E-enkynol. After 4 hours of irradiation, the irradiation was stopped, and the conversion rate of isoenkynol, the yield of enkynol, and the ratio of Z-isomer to E-isomer were determined by gas chromatography. The conversion rate of isoenkynol was 99.2%, the yield of enkynol was 50.9%, and the Z-enkynol:E-enkynol ratio was 91:9.

[0061] Comparative Example 6

[0062] Isoenkynol (Formula IV) was dissolved in toluene to produce a 20 wt% solution. A 30 wt% sulfuric acid solution was added as an initiator to the toluene solution of isoenkynol, with a volume ratio of sulfuric acid to isoenkynol solution of 1:5. The resulting solution was added to a beaker. A 470 nm LED blue light was placed 10 cm away from the outside, and the beaker contained circulating coolant, with the temperature controlled at 50 °C. The toluene solution was irradiated with continuous stirring, causing the isoenkynol to convert to Z-enkynol and E-enkynol. After 4 hours of irradiation, the irradiation was stopped, and the conversion rate of isoenkynol, the yield of enkynol, and the ratio of Z-isomer to E-isomer were determined by gas chromatography. The conversion rate of isoenkynol was 99.7%, the yield of enkynol was 30.1%, and the Z-enkynol:E-enkynol ratio was 91:9. Coking was evident in the reaction.

[0063] This comparative example shows that as temperature increases under illumination, the conversion rate increases, but the yield decreases.

[0064] Comparative Example 7

[0065] Isoenkynol (Formula IV) was dissolved in toluene to produce a 20 wt% solution. A 30 wt% sulfuric acid solution was added as an initiator to the toluene solution of isoenkynol, with a volume ratio of sulfuric acid to isoenkynol of 1:5. The resulting solution was added to a beaker. The toluene solution was directly heated to 50°C, at which point the isoenkynol was converted to Z-enkynol and E-enkynol. Heating was stopped after 1 hour, and the conversion rate of isoenkynol, the yield of enkynol, and the ratio of Z-isomer to E-isomer were determined by gas chromatography. The conversion rate of isoenkynol was 99.5%, the yield of enkynol was 75.6%, and the Z-enkynol:E-enkynol ratio was 85:15. Significant coking was observed in the reaction.

[0066] This comparative example shows that, without light, as temperature increases, conversion rate increases, yield decreases, and the cis-trans ratio decreases.

[0067] Example 5

[0068] Isoenkynol (Formula IV) was dissolved in toluene to produce a 10 wt% solution. A 10 wt% sulfuric acid solution was added as an initiator to the toluene solution of isoenkynol, with a sulfuric acid to isoenkynol solution volume ratio of 1:10. The resulting solution was added to a beaker. A 470 nm blue LED lamp with a light intensity of 30 mW / cm² was placed 10 cm away from the outside. 2 The beaker contained circulating coolant, and the temperature was controlled at 30°C. Under continuous stirring, the toluene solution was irradiated, causing isoenyne alcohol to convert into Z-enyne alcohol and E-enyne alcohol. After 2 hours of irradiation, the irradiation was stopped, and the conversion rate of isoenyne alcohol, the yield of enyne alcohol, and the ratio of Z-isomer to E-isomer were determined by gas chromatography. The conversion rate of isoenyne alcohol was 48.9%, the yield of enyne alcohol was 40.1%, and the Z-enyne alcohol:E-enyne alcohol ratio was 86:14.

[0069] Example 6

[0070] Isoenkynol (Formula IV) was dissolved in toluene to produce a 40 wt% solution. A 50 wt% sulfuric acid solution was added as an initiator to the toluene solution of isoenkynol, with a sulfuric acid to isoenkynol solution volume ratio of 1:1. The resulting solution was added to a beaker. A 470 nm blue LED lamp with a light intensity of 30 mW / cm² was placed 10 cm away from the outside. 2 The beaker contained circulating cooling liquid, and the temperature was controlled at 30°C. Under continuous stirring, the toluene solution was irradiated, causing isoenyne alcohol to convert into Z-enyne alcohol and E-enyne alcohol. After 2 hours of irradiation, the irradiation was stopped, and the conversion rate of isoenyne alcohol, the yield of enyne alcohol, and the ratio of Z-isomer to E-isomer were determined by gas chromatography. The conversion rate of isoenyne alcohol was 99.9%, the yield of enyne alcohol was 61.3%, and the Z-enyne alcohol:E-enyne alcohol ratio was 77:23.

[0071] The above description is merely a preferred embodiment of the present invention and does not limit the present invention. Any modifications and substitutions made within the scope of the present invention are included within the protection scope of the present invention.

Claims

1. A photocatalytic transisomerization process for isoenkynols, characterized in that, include: Under initiator and light conditions, the isoenynyl alcohol represented by formula (I) undergoes a transisomerization reaction in a mixed system of water and organic solvent to obtain E-pent-2-en-4-yn-1-ol represented by formula (II) and Z-pent-2-en-4-yn-1-ol represented by formula (III). In equations (I) to (III), R 1 R is hydrogen, alkyl, or aryl. 2 It is alkyl or aryl; The initiator is a protic acid; The wavelength of the illumination is 405nm to 480nm.

2. The photocatalytic transisomerization process of isoenkynols according to claim 1, characterized in that, The feeding method is as follows: The isoenkynol is dissolved in an organic solvent to form an isoenkynol solution, and the initiator is dissolved in water to form an initiator solution. The solutions are then mixed and reacted under the light conditions.

3. The photocatalytic transisomerization process of isoenkynols according to claim 2, characterized in that, The initiator is sulfuric acid or acetic acid; The concentration of the initiator solution is 5–50 wt%.

4. The photocatalytic transisomerization process of isoenkynols according to claim 3, characterized in that, The concentration of the isoenkynol solution is 10 wt% to 40 wt%. The volume ratio of the initiator solution to the enynol solution is 1 / 20 to 1 / 2.

5. The photocatalytic transisomerization process of isoenkynols according to claim 1, characterized in that, The illumination uses an LED light source; The power of the illumination is 50 mw / cm². 2 ~500mw / cm 2 .

6. The photocatalytic transisomerization process of isoenynyl alcohols according to claim 1, characterized in that, The R 1 For hydrogen, R 2 It is a methyl group.

7. The photocatalytic transisomerization process of isoenynyl alcohols according to claim 1, characterized in that, The organic solvent is an alcohol, a nitrile, an aromatic solvent, or a mixture thereof.

8. The photocatalytic transisomerization process of isoenkynols according to claim 7, characterized in that, The organic solvent is acetonitrile, toluene, or a mixture thereof.

9. The photocatalytic transisomerization process of isoenynyl alcohols according to claim 1, characterized in that, The temperature of the transisomerization reaction is 0–30°C, and the illumination time is 2–6 hours.

10. The photocatalytic transisomerization process of isoenkynols according to claim 1, characterized in that, After the reaction is complete, the following post-processing procedure is adopted: The enynyl alcohol isomer and aqueous solution were first separated by layering, and then E-pent-2-en-4-yn-1-ol and Z-pent-2-en-4-yn-1-ol were obtained by distillation.

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