Environment-friendly acetal preparation method

An environmentally friendly and acetal technology, which is applied in the preparation of organic compounds, chemical instruments and methods, organic chemistry, etc., can solve the problems of long reaction time, increase of reaction raw materials, and difficult environmental protection problems, and achieve easy handling and preparation process simple effect

Active Publication Date: 2021-10-01
老河口光联科技有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

At present, there are two main industrial methods for the separation of water in the acetal condensation reaction in my country. One is the adsorption of water by solid water-absorbing agents. It is difficult to dehydrate and regenerate the water-absorbing agent, and because the recycling efficiency of the water-absorbing agent is too low, a large amount of waste is generated, and the environmental protection problem is difficult to solve
The 2nd, add the preparation method of solvent reflux with water, its advantage is that the conversion rate that can promote reaction is higher, and shortcoming is that reflux with water efficiency is lower, and reaction time is long, needs more thermal energy to maintain reflux state, and, if Alcohols and aldehydes with low boiling points, this method cannot be carried out
Now, there is also the chemical water removal method, adding a chemical substance that can react with water to react the water produced, which adds new reaction raw materials, and the reaction will also produce new substances, increasing the difficulty of separation and the cost of raw materials

Method used

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Examples

Experimental program
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Effect test

Embodiment 1

[0022] An environment-friendly preparation method of acetal, comprising the steps of:

[0023] S1, first add 175.05g of cyclohexane (2.08mol) into the four-necked flask, then add 62.48g of methanol (1.95mol) and 0.69g of formic acid (0.015mol), and stir evenly, then slowly drop into the reaction kettle Add 58.08g of propionaldehyde (1mol), continue to stir during the dropwise addition, and control the reaction temperature at 30°C and the dropwise addition time at 8h;

[0024] S2, after the dropwise addition of propionaldehyde, the temperature of the reaction solution is lowered to 3° C., and the reaction is kept for 1 hour, and the conversion rate of propionaldehyde is ≥85%.

[0025] S3, after the reaction, adjust the pH of the reaction solution to 6, and let the reaction solution stand for 0.5 h, then remove the water in the lower layer, and rectify the reaction solution in the upper layer to obtain acetal with a purity of 98.3%.

Embodiment 2

[0027] An environment-friendly preparation method of acetal, comprising the steps of:

[0028] S1, first add 129.27g of n-hexane (1.5mol) into the four-necked flask, then add 71.13g of methanol (2.22mol) and 0.29g of methanesulfonic acid (0.003mol), and stir evenly, and then slowly pour into the reaction kettle Add 72.11 g of butyraldehyde (1 mol) dropwise, continue stirring during the dropwise addition, and control the reaction temperature at 50° C., and the dropping time at 5 h;

[0029] S2, after the butyraldehyde is added dropwise, the temperature of the reaction solution is lowered to 5° C., and the reaction is kept for 3 hours; at this time, the conversion rate of butyraldehyde is ≥85%.

[0030] S3, after the reaction, adjust the pH of the reaction solution to 7, and let the reaction solution stand for 1 hour, then remove the water in the lower layer, and rectify the reaction solution in the upper layer to obtain acetal with a purity of 97.4%.

Embodiment 3

[0032] An environment-friendly preparation method of acetal, comprising the steps of:

[0033] S1, first add 250.5g of n-heptane (2.5mol) into the four-necked flask, then add 67.28g of methanol (2.10mol) and 1.12g of p-toluenesulfonic acid (0.0065mol), and stir evenly, and then add Slowly add 72.11g of isobutyraldehyde (1mol) dropwise to the mixture, continue to stir during the dropwise addition, and control the reaction temperature at 40°C and the dropwise addition time at 6h;

[0034] S2, after the isobutyraldehyde is added dropwise, the temperature of the reaction solution is lowered to 4° C., and the reaction is kept for 2 hours; at this time, the conversion rate of isobutyraldehyde is ≥88%.

[0035] S3, after the reaction, adjust the pH of the reaction solution to 6.5, and let the reaction solution stand for 40 minutes, then remove the water in the lower layer, and rectify the reaction solution in the upper layer to obtain acetal with a purity of 99.5%.

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Abstract

The invention provides an environment-friendly acetal preparation method which comprises the following steps: S1, adding alcohol, a solvent and a catalyst into a reaction kettle, uniformly stirring, slowly dropwise adding aldehyde into the reaction kettle, continuously stirring in the dropwise adding process, controlling the reaction temperature to be 30-50 DEG C, and controlling the dropwise adding time to be 5-8 hours; S2, after the aldehyde is dropwise added, controlling the temperature of the reaction liquid to be 3-5 DEG C, and carrying out heat preservation reaction for 1-3 hours; and S3, after the reaction is finished, adjusting the pH value of the reaction liquid to 6-7, standing the reaction liquid for 0.5-1 hour, then removing water at the lower layer, and rectifying the reaction liquid at the upper layer to obtain the high-purity acetal. According to the method, water in a reaction system is dissociated at a lower reaction temperature, and the reaction system is changed into two phases, so that the water in an organic phase is reduced, the conversion rate is improved, and the method is low in wastewater generation amount, easy to treat, safe and environment-friendly, and is easy to implement and suitable for industrial large-scale preparation of acetal.

Description

technical field [0001] The invention relates to the field of preparation of acetal, in particular to an environment-friendly preparation method of acetal. Background technique [0002] Acetal, also known as acetal, is a mixture of aldehydes and alcohols that is catalyzed by an acid to continuously remove the water generated in the reaction to form acetals. It is an important intermediate for the production of alkenyl ethers. At present, there are two main industrial methods for the separation of water in the acetal condensation reaction in my country. One is the adsorption of water by solid water-absorbing agents. It is difficult to dehydrate and regenerate the water-absorbing agent, and because the recycling efficiency of the water-absorbing agent is too low, a large amount of waste is generated, and the environmental protection problem is difficult to solve. The 2nd, add the preparation method of solvent reflux with water, its advantage is that the conversion rate that can...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C41/56C07C43/303
CPCC07C41/56C07C43/303Y02P20/584
Inventor 陈瑞汤于兵吴朝林
Owner 老河口光联科技有限公司
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