CN115974690A - A kind of preparation method of 4-acetoxy-2-methyl-2-buten-1-aldehyde - Google Patents

Abstract

The invention relates to the technical field of organic chemical industry. The invention discloses a preparation method of 4-acetoxy-2-methyl-2-butene-1-aldehyde, which comprises the following steps: The product is mixed with water, and reacted at a certain temperature for 8 hours. After the reaction, it is left to stand for stratification, and the unreacted chloride is separated to obtain a quaternary ammonium salt solution; S2, a certain amount of acid is added to the quaternary ammonium salt solution. Adjust the pH; S3, add an organic phase solvent to the quaternary ammonium salt solution, and add a certain amount of copper catalyst, perform hydrolysis at a certain temperature, and separate the organic phase after the reaction; S4, add 1% to the product of S3 The concentration of sodium carbonate is adjusted to neutral, the organic phase is recovered, and five-carbon aldehyde is obtained by distillation under reduced pressure. In the present invention, the quaternary ammonium salt is obtained by mixing the chloride and urotropine with the water phase, and the organic phase and the copper catalyst are added to the quaternary ammonium salt to obtain the pentacarbon aldehyde, and the reaction temperature can be lowered by copper catalyzing the hydrolysis of the carbon-nitrogen bond. Improve the selectivity and yield of hydrolysis.

Description

A kind of preparation method of 4-acetoxy-2-methyl-2-butene-1-al

technical field

The invention relates to the technical field of organic chemical industry, in particular to a preparation method of 4-acetoxy-2-methyl-2-butene-1-aldehyde.

Background technique

4-Acetoxy-2-methyl-2-buten-1-aldehyde, referred to as five-carbon aldehyde, is a chemical synthesis product and an intermediate of vitamin A. The storage conditions are room temperature and sealed storage. Pentacarbonaldehyde is stable at room temperature and sealed conditions, but it should not be mixed with strong oxides, strong acids, and strong alkalis. Irritating to eyes, skin and respiratory props, poisonous if swallowed.

In general, there is a good yield when aromatic aldehyde is prepared by Sommelet reaction, and the yield is generally not high when aliphatic aldehyde is prepared. Patent GB736488 (1955) reports that formula 3 is hydrolyzed in aqueous solution to obtain target product formula 1, yield Only about 20%; in order to improve the yield, the patent US5471004A carries out the hydrolysis reaction in two phases, and adopts acid catalysis at the same time, reacts at a higher temperature, and the yield is obviously improved, but the product is hydrolyzed at a higher temperature under acidic conditions, and the product Complicated, it needs to be purified by column chromatography or purified by sodium bisulfite to remove impurities, which is inconvenient for industrialization and has a large loss; patent CN1919825A reports that the hydrolysis yield can be improved through microwave reactors, but microwave catalytic reactions cannot be used in large-scale industrial production. accomplish.

Contents of the invention

(1) Solved technical problems

Aiming at the deficiencies in the prior art, the present invention provides a preparation method of 4-acetoxy-2-methyl-2-buten-1-aldehyde, which can reduce the reaction temperature through the hydrolysis of copper-catalyzed carbon-nitrogen bond , to improve the selectivity and yield of hydrolysis; in addition, the product has high purity, and a high-purity product can be obtained by simple distillation.

(2) Technical solution

In order to achieve the above object, the present invention provides the following technical scheme: a preparation method of 4-acetoxy-2-methyl-2-buten-1-aldehyde, comprising the following steps:

S1, the chloride is mixed with urotropine and water, and reacted at a certain temperature for 8 hours. After the reaction, the stratification is left to stand, and the unreacted chloride is separated to obtain a quaternary ammonium salt solution.

S2, adding a certain amount of acid to the quaternary ammonium salt solution to adjust the pH;

S3, add organic phase solvent in the quaternary ammonium salt solution, and add a certain amount of copper catalyst, carry out hydrolysis at a certain temperature, the reaction time is 6 hours, divide and take organic phase after reaction finishes,

S4, adding 1% sodium carbonate to the product of S3 to adjust to neutrality, recovering the organic phase, and obtaining pentacarbon aldehyde by distillation under reduced pressure.

As a preferred solution, in S1, the molar ratio of chloride to urotropine is 1:1-1.5.

As a preferred solution, in S1, the reaction temperature of the chloride and urotropine in the aqueous phase is 25°C-80°C, preferably between 30°C-45°C.

As a preferred solution, in S1, the amount of water used is 1 to 10 times the mass of the chloride, preferably 2 to 4 times.

As a preferred version, in S3, the organic phase used is in toluene, xylene, n-heptane, n-hexane, cyclohexane, ethyl acetate, ethyl propionate, methyl tert-butyl ether and diethane One, and the amount of the organic phase is 1 to 3 times the volume of the aqueous phase.

As a preferred solution, in S2, adjust Ph=2-6 by acid, preferably pH=2.5-3.0.

As a preferred version, in S3, the copper catalyst used is one of copper sulfate, copper acetate, cuprous chloride, cupric chloride, the preferred copper catalyst is copper acetate, and the concentration of the copper catalyst in the aqueous phase (m/v) is between 0.5% and 5%, preferably between 0.8% and 1.5%.

As a preferred solution, in S3, the reaction temperature is between 20°C and 60°C, preferably between 25°C and 35°C.

(3) Beneficial effects

The present invention provides a kind of preparation method of 4-acetoxy-2-methyl-2-buten-1-al, the beneficial effect is:

In the present invention, the quaternary ammonium salt is obtained by mixing the chloride, urotropine and the water phase at a certain temperature, and then the quaternary ammonium salt is hydrolyzed, and an organic phase and a copper catalyst are added in the hydrolysis process to obtain pentacarbon aldehyde, and carbon-nitrogen is catalyzed by copper. The hydrolysis of the bond can reduce the reaction temperature, improve the selectivity and yield of hydrolysis, and the product has high purity, and a high-purity product can be obtained by simple distillation.

Detailed ways

In order to better understand the purpose, structure and function of the present invention, a preparation method of 4-acetoxy-2-methyl-2-buten-1-al of the present invention will be further described in detail.

A preparation method of 4-acetoxy-2-methyl-2-buten-1-aldehyde, comprising the following steps:

S1, the chloride is mixed with urotropine and water, and reacted at a certain temperature for 8 hours. After the reaction, the layers are left to stand, and the unreacted chloride is separated to obtain a quaternary ammonium salt solution.

S2, adding a certain amount of acid to the quaternary ammonium salt solution to adjust the pH;

S3, add organic phase solvent in the quaternary ammonium salt solution, and add a certain amount of copper catalyst, carry out hydrolysis at a certain temperature, the reaction time is 6 hours, divide and take organic phase after reaction finishes,

S4, adding 1% sodium carbonate to the product of S3 to adjust to neutrality, recovering the organic phase, and obtaining pentacarbon aldehyde by distillation under reduced pressure.

As a preferred solution, in S1, the molar ratio of chloride to urotropine is 1:1-1.5.

As a preferred solution, in S1, the reaction temperature of the chloride and urotropine in the aqueous phase is 25°C-80°C, preferably between 30°C-45°C.

As a preferred solution, in S1, the amount of water used is 1 to 10 times the mass of the chloride, preferably 2 to 4 times.

As a preferred version, in S3, the organic phase used is in toluene, xylene, n-heptane, n-hexane, cyclohexane, ethyl acetate, ethyl propionate, methyl tert-butyl ether and diethane One, and the amount of the organic phase is 1 to 3 times the volume of the aqueous phase.

As a preferred solution, in S2, adjust Ph=2-6 by acid, preferably pH=2.5-3.0.

As a preferred version, in S3, the copper catalyst used is one of copper sulfate, copper acetate, cuprous chloride, cupric chloride, the preferred copper catalyst is copper acetate, and the concentration of the copper catalyst in the aqueous phase (m/v) is between 0.5% and 5%, preferably between 0.8% and 1.5%.

As a preferred solution, in S3, the reaction temperature is between 20°C and 60°C, preferably between 25°C and 35°C.

Example 1

Take 65g (0.4mol) of chloride, 84g (0.6mol) of urotropine, add 195g of water, react at 30°C for 8 hours, then let it stand for stratification, remove 6.2g of chloride that has not participated in the reaction, add the water phase 3 grams of 50% hydrochloric acid to adjust the pH to 3.5, add 0.98 grams of cuprous chloride, then add 390 ml of n-heptane, react at 35 ° C for 6 hours, separate the organic phase after the reaction, and adjust it to neutral with 1% sodium carbonate. properties, recover the organic phase, and then distill the crude product under reduced pressure to obtain 41.62 g of 4-acetoxy-2-methyl-2-buten-1-aldehyde, with a gas phase content of 97.71%, and the yield is calculated based on the actual reacted chloride 81%;

4-Acetoxy-2-methyl-2-buten-1-aldehyde NMR data: ¹ H-NMR (CDCl ₃ , 300MHz): δ9.48(s,-CHO); 6.51(t,H,- CH=);

4.91(d,2H,-CH2-); 2.15(s,3H,-CH3); 1.80(s,3H,=C-CH3);

Example 2

Take 65g (0.4mol) of chloride, 67.2g (0.48mol) of urotropine, add 240g of water, react at 30°C for 8 hours, then let it stand and separate the layers, remove 6.5g of chloride that has not participated in the reaction, and the water phase Add 4 grams of acetic acid to adjust the pH to 3.0, add 2.4 grams of copper acetate, then add 300 ml of toluene, react at 30 ° C for 6 hours, separate the organic phase after the reaction, adjust it to neutral with 1% sodium carbonate, and recover the organic phase , and then distill the crude product under reduced pressure to obtain 43.45 g of 4-acetoxy-2-methyl-2-butene-1-al, with a gas phase content of 97.65%, and a yield of 85% based on the actual reacted chloride.

It can be understood that the present invention is described through some embodiments, and those skilled in the art know that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, the features and examples may be modified to adapt a particular situation and material to the teachings of the invention without departing from the spirit and scope of the invention. Therefore, the present invention is not limited by the specific embodiments disclosed here, and all embodiments falling within the scope of the claims of the present application belong to the protection scope of the present invention.

Claims (8)

1. A preparation method of 4-acetoxyl-2-methyl-2-butene-1-aldehyde is characterized by comprising the following steps:

s1, mixing chloride, urotropine and water, reacting for 8 hours at a certain temperature, standing for layering after the reaction is finished, removing unreacted chloride to obtain a quaternary ammonium salt solution,

s2, adding a certain amount of acid into the quaternary ammonium salt solution to adjust the PH;

s3, adding an organic phase solvent into the quaternary ammonium salt solution, adding a certain amount of copper catalyst, hydrolyzing at a certain temperature for 6 hours, separating an organic phase after the reaction is finished,

and S4, adding 1% of sodium carbonate into the product of the S3 to adjust to be neutral, recovering an organic phase, and carrying out reduced pressure distillation to obtain the pentanal.

2. The process according to claim 1 for producing 4-acetoxy-2-methyl-2-buten-1-al, which comprises: in S1, the mol ratio of chloride to urotropine is 1:1 to 1.5.

3. The process according to claim 1 for producing 4-acetoxy-2-methyl-2-buten-1-al, which comprises: in S1, the reaction temperature of chloride and urotropine in the water phase is 25-80 ℃.

4. The process according to claim 1 for producing 4-acetoxy-2-methyl-2-buten-1-al, which comprises: in S1, the amount of water is 1 to 10 times the amount of the chloride.

5. The process for producing 4-acetoxy-2-methyl-2-butene-1-al according to claim 1, wherein: in S3, the organic phase is one of toluene, xylene, n-heptane, n-hexane, cyclohexane, ethyl acetate, ethyl propionate, methyl tert-butyl ether and dichloroethane, and the amount of the organic phase is 1 to 3 times of the volume of the aqueous phase.

6. The process for producing 4-acetoxy-2-methyl-2-butene-1-al according to claim 1, wherein: in S2, ph =2 to 6 is adjusted by an acid.

7. The process according to claim 1 for producing 4-acetoxy-2-methyl-2-buten-1-al, which comprises: in S3, the used copper catalyst is one of copper sulfate, copper acetate, cuprous chloride and copper chloride, and the concentration (m/v) of the copper catalyst in the water phase is between 0.5 and 5 percent.

8. The process according to claim 1 for producing 4-acetoxy-2-methyl-2-buten-1-al, which comprises: in S3, the reaction temperature is 20-60 ℃.