阅读说明：本技术 一种合成丙炔醇的方法 (Method for synthesizing propiolic alcohol ) 是由 王南 曾健 孔林 李代军 孙晓丽 叶小琼 于 2021-08-30 设计创作，主要内容包括：一种合成丙炔醇的方法,采用多聚甲醛为甲醛原料来源,以氢氧化钾或醇钾为催化剂,在芳香烃或脂肪烃有机溶剂中,与低于0.15MPa压力的乙炔进行反应生成丙炔醇。反应终点物料是“液-液”两相体系,经沉降分离、水解分离、萃取提纯和精馏分离收取产物,产物中丙炔醇收率可达71%～73%。(A process for synthesizing propiolic alcohol includes such steps as using paraformaldehyde as raw material of formaldehyde, using potassium hydroxide or potassium alcoholate as catalyst, and reacting it with acetylene under 0.15MPa in the organic solvent of aromatic or aliphatic hydrocarbon to obtain propiolic alcohol. The reaction end material is a liquid-liquid two-phase system, and the product is obtained through settling separation, hydrolysis separation, extraction purification and rectification separation, and the yield of the propiolic alcohol in the product can reach 71-73%.)

1. A synthetic method of propiolic alcohol is characterized by comprising the following steps:

(1) preparation of the Formaldehyde solution

Stirring and heating initial raw material paraformaldehyde and an organic solvent together, and depolymerizing by using potassium alcoholate as a catalyst to prepare a formaldehyde solution;

(2) preparation of catalyst suspension slurry

Grinding an organic solvent and a catalyst into slurry, stirring and heating to make the slurry transparent or semitransparent, and cooling to prepare catalyst suspension slurry;

(3) synthesis reaction

Introducing acetylene into the prepared catalyst suspension slurry, firstly, fully activating the reaction of acetylene and the catalyst, then, adding the formaldehyde solution prepared in the step (1) in a uniform flow manner, continuously controlling the temperature and keeping the acetylene pressure for reaction, wherein the material at the end point of the reaction is a liquid-liquid two-phase system consisting of an organic solvent, and propiolic alcohol-catalyst complex and butynediol-catalyst complex micro-liquid particles dispersed in the organic solvent;

(4) settling separation and hydrolysis separation

Settling and separating the reaction end material, and respectively collecting a reaction product phase containing the propiolic alcohol-catalyst complex and the butynediol-catalyst complex and an organic solvent phase;

stirring and hydrolyzing the reaction product phase with clear water to generate an aqueous phase liquid containing propiolic alcohol, 1, 4-butynediol and potassium hydroxide and a small amount of organic solvent phase;

(5) extraction separation concentration and fractional distillation purification

Mixing and extracting the obtained aqueous phase liquid and an organic extraction solvent in extraction equipment, and respectively collecting an organic extraction phase containing propiolic alcohol and 1, 4-butynediol and a raffinate aqueous phase containing potassium hydroxide;

and (3) rectifying and separating the organic extraction phase to obtain the propiolic alcohol and the 1, 4-butynediol products respectively.

2. A process for the synthesis of propargyl alcohol according to claim 1, wherein in step (1) and step (2), the organic solvent used simultaneously satisfies the following three conditions:

the formaldehyde has high solubility, and the solubility of the formaldehyde in the organic solvent is more than 20 percent;

② the solubility to the propiolic alcohol is small, the solubility of the propiolic alcohol in the organic solvent is less than 2 percent;

the solubility of the compound and water is very low;

further, the organic solvent is selected from aromatic hydrocarbon solvents such as toluene, o-xylene, m-xylene, p-xylene, mixed xylene, and ethylbenzene, and aliphatic hydrocarbon solvents such as n-hexane, 2-methylpentane, 3-methylpentane, heptane, octane, solvent oil, and petroleum ether.

3. A process for the synthesis of propargyl alcohol according to claim 1, wherein in step (1), the formaldehyde solution is prepared with a formaldehyde concentration of 20% to 45%, and further preferably with a formaldehyde concentration of 35% to 40%.

4. A process for the synthesis of propargyl alcohol according to claim 1, wherein in step (2) the catalyst used is potassium hydroxide, potassium iso-butoxide or potassium tert-butoxide; when potassium hydroxide is selected as the catalyst, potassium hydroxide (pure) and an organic solvent =0.3:1 to 0.6:1 (weight ratio), and further, potassium hydroxide (pure) and an organic solvent =0.4:1 to 0.5:1 (weight ratio) are preferable; when potassium isobutyl alkoxide or potassium tert-butyl alkoxide is used as the catalyst, potassium alkoxide (pure substance) and the organic solvent = 0.5:1 to 1:1 (weight ratio), and further, potassium alkoxide (pure substance) and the organic solvent =0.7:1 to 0.9:1 (weight ratio) are preferable.

5. A process for the synthesis of propargyl alcohol according to claim 1, wherein in step (3), the molar ratio of formaldehyde to catalyst in the reaction starting material is controlled to be less than or equal to 1, and further preferably, the molar ratio of formaldehyde to catalyst is = 0.8:1 to 0.9: 1; the reaction temperature is controlled within the range of 5-20 ℃; the acetylene pressure is always kept less than or equal to 0.15MPa in the reaction process, and further, the acetylene pressure is preferably 0.08MPa to 0.15 MPa.

6. A process for the synthesis of propargyl alcohol according to claim 1, wherein in step (4), the ratio of clear water to the reaction product phase is from 1:1 to 3:1 (weight ratio), and further preferably the ratio of clear water to the reaction product phase is from 1.5:1 to 2.5:1 (weight ratio); the hydrolysis temperature is 30-50 ℃, and the hydrolysis reaction time is 30-60 minutes.

7. The process for synthesizing propargyl alcohol according to claim 1, wherein the organic extraction solvent used in step (5) is an alcohol solvent having a low miscibility with water, and the organic extraction solvent is an aqueous phase liquid = 0.5:1 to 1:1 (weight ratio), and the extraction temperature is 30 to 50 ℃.

Technical Field

The invention relates to a compound synthesis method, in particular to a method for synthesizing propiolic alcohol from polyformaldehyde through reaction with acetylene safely and with high yield.

Background

The propiolic alcohol is also called 2-propin-1-alcohol and ethynyl methanol, is colorless transparent liquid at normal temperature, and is an important organic intermediate raw material. In the pharmaceutical industry, propiolic alcohol is an important intermediate for synthesizing fosfomycin sodium, fosfomycin calcium and sulfadiazine; in the pesticide industry, the propargyl alcohol can be used for synthesizing a propargite pesticide, a bactericide and the like; in the electroplating industry, propiolic alcohol and its downstream derivatives are excellent copper plating or nickel plating glazing agents; in the steel industry and oil exploitation, propiolic alcohol and its downstream compounds are also used as rust inhibitors and acidizing corrosion inhibitors.

At present, the most widely used preparation method of propiolic alcohol at home and abroad is a co-production process method for generating propiolic alcohol and butynediol by the reaction of formaldehyde water solution and acetylene gas. Because the generated propiolic alcohol is very active in the synthesis reaction process, the propiolic alcohol is very easy to be further added with formaldehyde to form 1, 4-butynediol, and particularly, when the acetylene pressure is lower, the reaction products basically generate the 1, 4-butynediol. In order to improve the yield of the propiolic alcohol, the current domestic and foreign industrial production widely adopts an acetylene aldehyde synthesis method for simultaneously improving the acetylene pressure by low formaldehyde concentration, namely, copper acetylide (or copper oxide-bismuth oxide) is used as a catalyst, 6 to 10 percent (or 9 to 15 percent) of formaldehyde aqueous solution is used as a formaldehyde raw material, and the synthesis reaction is carried out in acetylene gas with the high pressure of 0.5 to 2MPa and the temperature of 90 to 130 ℃. And after the reaction is finished, filter-pressing and separating to remove catalyst slag, collecting reactant feed liquid containing less than 10% of reaction products, wherein the highest content of the target product propiolic alcohol is only 3% -4%, rectifying and separating the reactant feed liquid, and respectively collecting propiolic alcohol and 1, 4-butynediol.

The synthesis process uses formaldehyde water solution as the source of formaldehyde raw material, and has the disadvantages of troublesome transportation and storage, especially the following:

1. there are serious potential safety hazards: because the solubility of acetylene in water is low, if the acetylene pressure is lower than 0.15MPa, the concentration of acetylene dissolved in water is very low, and 1, 4-butynediol is mainly generated in the reaction. In order to achieve the purpose of dissolving acetylene in water sufficiently to meet the reaction requirement, high acetylene pressure (more than 0.5 MPa) is generally adopted, and due to the explosion danger of acetylene gas with the pressure exceeding 0.15MPa and the use of catalysts such as copper acetylide and the like which are flammable and explosive in the air, the production method has serious explosion safety hidden trouble.

2. The yield of the propiolic alcohol product is low: in the synthesis reaction process, the generated propiolic alcohol is active in chemical property and is easy to further perform addition reaction with formaldehyde under the action of a catalyst to generate 1, 4-butynediol, so the production ratio of the propiolic alcohol and the 1, 4-butynediol obtained by the process method is usually 1: 9-1: 2, namely the yield of the propiolic alcohol is usually less than one third of that of a final product.

3. The production efficiency is low and the energy consumption is large: in order to improve the yield of the propiolic alcohol, the process method adopts a method of reducing the concentration of formaldehyde in water liquid while improving the acetylene pressure so as to inhibit the generation of 1, 4-butynediol, and generally controls the initial concentration of the formaldehyde to be 6-10 percent, so that the product concentration is lower, the subsequent rectification separation water is more, and the production efficiency is lower, and the energy consumption is higher.

Disclosure of Invention

The invention aims to provide a method for synthesizing propiolic alcohol under safe acetylene pressure and a safe catalyst, and aims to improve the yield of the propiolic alcohol and reduce the production energy consumption.

The purpose of the invention is realized as follows: the production and synthesis of the propiolic alcohol are carried out by taking paraformaldehyde and acetylene as initial raw materials, potassium hydroxide or potassium alcoholate as a catalyst and an organic solvent as a dispersing agent according to the following technical scheme.

1. Preparation of the Formaldehyde solution

Stirring starting raw materials of paraformaldehyde and an organic solvent together, adding potassium alcoholate, heating, carrying out depolymerization reaction on the paraformaldehyde under catalysis of the potassium alcoholate to generate formaldehyde, and dissolving the formaldehyde in the organic solvent until all paraformaldehyde particles suspended in the solvent are depolymerized and dissolved in the organic solvent. After the depolymerization reaction is finished, cooling to 15-25 ℃, and sealing for later use.

The feeding proportion of the paraformaldehyde and the organic solvent is controlled to control the formaldehyde content in the prepared formaldehyde solution to be 20-45%, and the concentration of the formaldehyde solution is preferably 35-40%.

The dosage of the depolymerization catalyst potassium alcoholate is 1-5% of the weight of the paraformaldehyde.

The depolymerization reaction temperature is 40-60 ℃.

The depolymerization reaction time is related to the reaction temperature and the dosage of catalyst potassium alcoholate, the depolymerization speed is relatively fast when the depolymerization reaction temperature is high, but the formaldehyde generated by depolymerization volatilizes and escapes when the temperature is too high. The depolymerization rate is improved with the increase of the catalyst dosage, but the depolymerization rate is not improved significantly after the catalyst dosage is increased to about 5% of the weight of the paraformaldehyde. In general, it takes about 3 to 5 hours to depolymerize 98% or more of paraformaldehyde completely dissolved in an organic solvent.

The paraformaldehyde is solid formaldehyde with high formaldehyde content, is in solid granular shape, has stable chemical properties, is convenient to store and transport, and can be depolymerized into formaldehyde under certain conditions.

The potassium alkoxide may be potassium methoxide, potassium ethoxide, potassium isobutoxide, potassium tert-butoxide, etc., and is used as depolymerization catalyst.

The organic solvent used in this step must satisfy simultaneously (1) a greater solubility for formaldehyde, the solubility of formaldehyde in the organic solvent being greater than 20%; (2) the solubility to the propiolic alcohol is small, and the solubility of the propiolic alcohol in the organic solvent is less than 2 percent; (3) has little solubility with water. The organic solvent satisfying the three conditions includes aromatic hydrocarbon solvents such as toluene, o-xylene, m-xylene, p-xylene, mixed xylene and ethylbenzene, and aliphatic hydrocarbon solvents such as n-hexane, 2-methylpentane, 3-methylpentane, heptane, octane, solvent oil and petroleum ether.

2. Preparation of catalyst suspension slurry

Grinding an organic solvent and a catalyst into slurry in grinding equipment, then transferring the slurry into reaction equipment, stirring and heating the slurry to 60-80 ℃, keeping the temperature for 0.5-1 hour, and continuing stirring and slowly cooling the slurry to a specified reaction temperature range after the material is in a transparent or nearly transparent state, namely the catalyst is completely or mostly dissolved in the organic solvent. After the temperature is reduced, the organic solution is in a semitransparent state, and the catalyst is uniformly dispersed in the organic solution in the form of fine suspended particles in a partially dissolved part. After the catalyst suspension slurry is prepared, the next step of 'synthetic reaction' operation is carried out as soon as possible without stopping stirring.

The catalyst used in this step is potassium hydroxide (industrial grade, purity 92% -94%), potassium iso-butoxide or potassium tert-butoxide, any one of them.

The organic solvent used in this step was the same as that used in the previous preparation of the formaldehyde solution.

The feeding ratio of the catalyst and the organic solvent is determined according to the type of the catalyst, when potassium hydroxide is selected as the catalyst, the weight ratio of potassium hydroxide (pure substance) to the organic solvent =0.3: 1-0.6: 1, preferably the weight ratio of potassium hydroxide (pure substance) to the organic solvent =0.4: 1-0.5: 1; when potassium iso-butoxide or potassium tert-butoxide is selected as the catalyst, potassium alkoxide (neat) organic solvent = 0.5:1 to 1:1 (weight ratio), preferably potassium alkoxide (neat) organic solvent =0.7:1 to 0.9:1 (weight ratio).

3. Synthesis reaction

And after the temperature of the catalyst suspension slurry prepared in the reaction equipment is controlled within a specified reaction temperature range, introducing acetylene into the material, keeping the acetylene pressure in the reaction equipment within the specified range, and reacting for about 1 hour to ensure that the acetylene and the catalyst react and are fully activated to generate active acetylene. Then adding the prepared formaldehyde solution into a reaction device in a uniform flow manner, continuously controlling the temperature and keeping the acetylene pressure, and carrying out addition reaction on the formaldehyde and the active acetylene until the formaldehyde reaction conversion in the material reaches more than 98%.

In the one-step operation, the adding amount of the formaldehyde solution is determined by the concentration of formaldehyde and the amount of the catalyst in the catalyst suspension slurry, namely, the molar ratio of formaldehyde to the catalyst in the reaction initial material is controlled to be less than or equal to 1 (molar ratio), preferably, the molar ratio of formaldehyde to the catalyst in the reaction initial material is = 0.8: 1-0.9: 1 (molar ratio), namely, the molar amount of formaldehyde in the reaction material is always ensured to be less than the molar amount of active acetylene, and the control of the formaldehyde shortage in the reaction material is helpful for inhibiting the generation of the byproduct 1, 4-butynediol.

The initial reaction temperature is controlled at 5-7 deg.c, and the reaction temperature is raised gradually and the later reaction temperature is raised to 18-20 deg.c.

The acetylene pressure is always kept less than or equal to 0.15MPa, preferably 0.08MPa to 0.15MPa in the reaction process.

The reaction time is usually 1.5-3 hours, and the formaldehyde conversion rate can reach more than 98%.

In this step, acetylene reacts with the suspended catalyst continuously to form active acetylene and the active acetylene is dissolved in the organic solvent, and the active acetylene molecules collide with formaldehyde molecules dissolved in the organic solvent to produce addition reaction, thereby forming a propiolic alcohol-catalyst complex. Because the solubility of the propiolic alcohol-catalyst complex in the selected organic solvent is very low, the molecules of the propiolic alcohol-catalyst complex generated by the reaction are mutually aggregated into fine droplets to be separated out, and the propiolic alcohol-catalyst complex is suspended and dispersed in the organic solvent, so that the propiolic alcohol-catalyst complex is not easy to further react with formaldehyde, and the generation of the 1, 4-butynediol is effectively reduced. Therefore, as the reaction proceeds, the catalyst particles suspended in the reaction mass gradually convert to active acetylene and disappear, the produced propiolic alcohol-catalyst complex and the by-product butynediol-catalyst complex are continuously precipitated, and after the reaction end point is reached, the reaction mass becomes a "liquid-liquid" two-phase system composed of an organic solvent and reaction product (propiolic alcohol-catalyst complex and butynediol-catalyst complex) particles dispersed therein.

4. Settling separation and hydrolysis separation

And (3) transferring the reaction termination material to a settling separation device after the reaction termination, separating the two phases of the reaction product phase (containing the propiolic alcohol-catalyst complex and the butynediol-catalyst complex) and the organic solvent phase, and collecting the two phases respectively. Wherein, the organic solvent is recycled after being recovered and treated,

and stirring and mixing the reaction product phase and clear water together, wherein the propargyl alcohol-catalyst complex (and butynediol-catalyst complex) is hydrolyzed and decomposed into propargyl alcohol, 1, 4-butynediol and potassium hydroxide, and the propargyl alcohol, the 1, 4-butynediol and the potassium hydroxide are dissolved into a water phase. And (3) settling and separating the hydrolyzed materials to respectively obtain an aqueous phase liquid (containing propiolic alcohol, 1, 4-butynediol and potassium hydroxide) and a residual small amount of organic solvent phase. Wherein, the organic solvent is recycled and reused, and the aqueous phase liquid enters the next operation of extraction, separation, concentration, fractionation and purification.

In the operation of the step, the adding amount of the clear water for hydrolysis is calculated according to the amount of a reaction material phase, namely the clear water to reaction product phase = 1: 1-3: 1 (weight ratio), and the concentration of the reaction products (propargyl alcohol and butynediol) in the water phase liquid after hydrolysis is 31-13% and the concentration of potassium hydroxide is 36-16%. Preferably, the weight ratio of clear water to the reaction product phase is 1.5: 1-2.5: 1, and the concentration of the reaction products (propargyl alcohol and butynediol) in the aqueous phase liquid after hydrolysis is 23-15% and the concentration of potassium hydroxide is 27-18%.

The hydrolysis temperature is 30-50 ℃. The hydrolysis reaction time is 30-60 minutes.

5. Extraction separation concentration and fractional distillation purification

Mixing the obtained aqueous phase liquid with an organic extraction solvent in an extraction device for extraction, transferring the propiolic alcohol and the 1, 4-butynediol in the aqueous phase liquid into an organic solvent phase, and collecting an organic solution phase (an organic extraction phase containing the propiolic alcohol and the 1, 4-butynediol) and an aqueous phase (a raffinate aqueous phase containing potassium hydroxide) respectively while retaining the potassium hydroxide in the aqueous phase liquid.

In this step, the amount of the organic extraction solvent to be added depends on the content of the reaction product in the aqueous phase of hydrolysis, and the concentration of the reaction product (propargyl alcohol and butynediol) in the organic extraction phase is controlled to be in the range of 30% to 25% by weight, usually using an organic extraction solvent: aqueous phase = 0.5:1 to 1: 1.

The extraction temperature is 30-50 ℃.

The organic extraction solvent used in the operation is alcohol solvent with small water intersolubility, and the alcohol meeting the condition comprises n-butyl alcohol, isobutyl alcohol, n-amyl alcohol, isoamyl alcohol, n-hexyl alcohol, 2-hexanol, 2-ethylbutanol, 2-ethylhexanol, n-octanol and the like.

Since the solubility of propiolic alcohol and 1, 4-butynediol in alcoholic organic solvents is much higher than that of water, during extraction the propiolic alcohol and 1, 4-butynediol are transferred from the aqueous phase to the organic extraction phase, and a solution with a higher concentration can be formed. While potassium hydroxide is not dissolved in the organic solvent and remains in the aqueous phase, the propargyl alcohol and 1, 4-butynediol can be efficiently separated by extraction.

And (3) after the organic extraction phase is subjected to adsorption, decoloration and other treatments, the rectification and separation are carried out, and the high-purity propiolic alcohol and 1, 4-butynediol products can be respectively obtained.

Compared with the prior art, the invention has the beneficial effects that:

1. paraformaldehyde is used as a starting material to replace formaldehyde water solution, and the starting material is rich in source, convenient and safe to transport and store.

2. Acetylene gas and a safe catalyst under the safe pressure of 0.15MPa are adopted in the synthetic reaction process, so that the explosion hazard is eliminated, and the production safety is ensured.

3. The conversion rate of formaldehyde in the reaction system reaches more than 98 percent, and the yield of the target product propiolic alcohol in the generated product can reach 69 to 73 percent.

4. Through the technical measures of low energy consumption, such as sedimentation separation, extraction concentration and the like, the material quantity of the subsequent rectification treatment is greatly reduced, and the production energy consumption is obviously reduced.

Detailed Description

Example 1:

(1) adding 200g of solvent toluene and 120g of paraformaldehyde into a glass reaction kettle in sequence, starting stirring, adding 2.5g of potassium ethoxide, heating to 55-60 ℃, keeping for about 3.5 hours, and sampling to detect that the depolymerization rate exceeds 98% after the paraformaldehyde is completely dissolved. Cooling to below 25 deg.C, and sealing. The formaldehyde concentration in the formaldehyde solution was about 37.5%.

(2) 600g of toluene and 300g of potassium hydroxide (industrial grade, purity 94%) are sequentially added into a grinder to be ground into slurry, the slurry is transferred into a stainless steel pressure reaction kettle, stirring is started, the temperature is heated to 70-80 ℃ for 1 hour, and then the temperature is reduced to 5-7 ℃ for control.

(3) And introducing acetylene gas, and keeping the acetylene pressure within the range of 0.12MPa to 0.14MPa for reaction for about 1 hour. And then uniformly and slowly adding the prepared formaldehyde solution into the reaction kettle from the elevated tank, controlling the adding to be finished within 30-40 minutes, simultaneously keeping the acetylene pressure within the range of 0.12-0.14 MPa for reaction, and gradually raising the reaction temperature to 20 ℃ at the speed of raising the temperature by 1-2 ℃ every 10 minutes and then keeping the reaction temperature. The reaction was carried out for about 2 hours, the residual formaldehyde in the reaction mass was 0.8% by sampling and the reaction was terminated after about half an hour of sampling. Upon discharge, the reaction mass was observed to have changed from an initial white translucent state to a grayish yellow turbid state.

In the reaction starting mixture, formaldehyde: potassium hydroxide (neat) = 0.8:1 (molar ratio).

(4) The reaction-terminated material was transferred into a conical flask, and allowed to stand to separate the material into two layers, the lower layer being a grayish yellow (reaction product) liquid phase and the upper layer being a nearly transparent colorless toluene solvent phase. Discharging and collecting respectively.

(5) Transferring the reaction product phase into a glass kettle, adding 950g of clear water, controlling the temperature to be 30-40 ℃, stirring for about 40 minutes, transferring into a conical flask, standing, dividing into a lower large amount of (containing the reaction product and potassium hydroxide) light yellow aqueous phase and an upper small amount of near-colorless transparent organic solvent phase, discharging and collecting respectively.

(6) Transferring the water phase liquid containing the reaction product and potassium hydroxide into a glass kettle, adding 500g of isobutanol, controlling the temperature to be 30-40 ℃, stirring for about 20 minutes, transferring the material into a conical flask, standing and layering. The extraction oil phase (containing the concentration of the reaction product is about 29%) and the extraction water phase (containing the concentration of potassium hydroxide is about 19%) are respectively collected after discharging.

(7) And adsorbing and decoloring the extracted oil phase by using activated carbon, fractionating by using an experimental glass rectifier, and respectively collecting each fraction.

137.7g of propiolic alcohol (purity 98.2%) and 55.7g of 1, 4-butynediol (purity 97.7%) are obtained, wherein the propiolic alcohol is 1, 4-butynediol = 71.3% and 28.7% in the product.

Example 2:

the procedure was followed as in example 1, wherein:

the feeding materials in the operation step (1) are 200g of mixed xylene, 140g of paraformaldehyde and 3g of potassium ethoxide, and the concentration of the prepared formaldehyde solution is about 41%.

650g of mixed xylene and 580g of potassium tert-butoxide serving as a catalyst are fed in the operation step (2).

In the operation step (3), the formaldehyde-potassium tert-butoxide = 0.9:1 (molar ratio) and the acetylene pressure is controlled to be 0.08MPa to 0.1 MPa.

The amount of clear water added in the operation step (5) was 1100 g.

The feed of the extraction solvent in the operation (6) was 600g of 2-ethylhexanol.

161.2g of propiolic alcohol (with the purity of 98.4%) and 59.7g of 1, 4-butynediol (with the purity of 97.2%) are obtained by rectification, and the propiolic alcohol in the product is 1, 4-butynediol = 73.2% and 26.8%.

Example 3:

the procedure was followed as in example 1, wherein:

in the operation step (1), the solvent n-hexane is 200g, the solvent paraformaldehyde is 130g, the solvent potassium ethoxide is 2g, and the concentration of the prepared formaldehyde solution is 39.3%.

In the operation step (2), 750g of n-hexane serving as a solvent and 300g of potassium hydroxide serving as a catalyst are fed.

In the operation step (3), the formaldehyde-potassium hydroxide = 0.85: 1 (molar ratio) and the acetylene pressure is controlled to be 0.1MPa to 0.12 MPa.

The amount of clear water added in the operation step (5) was 1000 g.

The feed of the extraction solvent in the operation (6) was 550g of 2-ethylhexanol.

The propargyl alcohol (purity 98.2%) 142.7g, 1, 4-butynediol (purity 97.6%) 52.4g are obtained by rectification, and the propargyl alcohol in the product is 1, 4-butynediol = 69.7% and 30.3%.

Example 4:

the procedure was followed as in example 1, wherein:

in the operation step (1), the solvent petroleum ether 200g, paraformaldehyde 130g and potassium ethoxide 3g are fed, and the concentration of the prepared formaldehyde solution is 39.2%.

The material used in the operation step (2) is solvent petroleum ether 550g, catalyst potassium tert-butoxide 540 g.

In the operation step (3), the formaldehyde-potassium hydroxide = 0.9:1 (molar ratio) and the acetylene pressure is controlled to be 0.08MPa to 0.1 MPa.

The amount of clear water added in the operation step (5) was 1100 g.

The amount of the extraction solvent fed in the operation (6) was 550g of isobutanol.

The propargyl alcohol (purity 98.7%) 140.8g and 1, 4-butynediol (purity 97.9%) 58.3g are obtained by rectification, and the propargyl alcohol in the product is 1, 4-butynediol = 70.9% and 29.1%.