Synthetic process of methylacrolein

A technology of methacrolein and synthesis process, which is applied in the preparation of carbonyl compounds, the separation/purification of carbonyl compounds, the preparation of organic compounds, etc. It can solve problems such as the inability to balance rate and selectivity, and achieve the effect of solving potential dangers, harsh solution conditions and high utilization rate.

Inactive Publication Date: 2015-04-29
成都建中香料香精有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] In view of this, the application provides a synthesis process of methacrolein, the yield of methacrolein synthesized by the process method is above 97%, the purity is above 97%, and the selectivity is nearly 100%. The catalyst can be recycled at least 20 times, which solves the problems that the yield and selectivity cannot be balanced in the traditional method, the recycling of the catalyst is not good, and the quality of methacrolein is not good.

Method used

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  • Synthetic process of methylacrolein
  • Synthetic process of methylacrolein
  • Synthetic process of methylacrolein

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] A method for synthesizing methacrolein, using paraformaldehyde and propionaldehyde to synthesize methacrolein under the condition of morpholine hydrochloride as a catalyst.

[0024] The specific operation steps of the synthesis process are as follows: add an appropriate amount of paraformaldehyde to the morpholine hydrochloride solution, raise the temperature to 80°C to completely dissolve the paraformaldehyde in the solution, and then lower the temperature, drop an appropriate amount of propionaldehyde into the above solution. The adding temperature is stabilized at a certain temperature. After all propionaldehyde is dropped into the solution, it is heated to 50-60°C for reaction. After the gas phase detection reaction is over, the temperature is raised to 67-110°C for atmospheric distillation, and the distilled product is allowed to stand for stratification. , The separated oil phase is methacrolein, and the separated water phase is returned to the reaction system for rec...

Embodiment 2

[0032] The synthesis process of Example 1 was used to synthesize methacrolein, in which the weight ratio of morpholine hydrochloride solution and propionaldehyde was 3-5, and 3 control examples were set up, respectively, the dripping temperature of propionaldehyde was 15-35℃, 35 -40℃, 40-50℃, respectively number the methacrolein synthesized at different dropping temperature as Ⅰ, Ⅱ, and Ⅲ. The products obtained after the reaction were sampled and detected by LC / MS to obtain the methacrolein Yield, selectivity, purity, experimental data are shown in Table 2.

[0033] Table 2 Test results of dimethyl acrolein products in Example

[0034] Yield (%) Selectivity (%) purity(%) Ⅰ97.799.998.4 Ⅱ98.799.999.2 Ⅲ 97.299.597.3

[0035] From the above experimental data, it can be seen that the yields of groups I-III are all above 97%, the purity is above 97%, and the selectivity is above 99%, which is close to 100%. Therefore, it can be seen that the synthesis of the technical scheme of th...

Embodiment 3

[0037] Synthesize methacrolein using the synthesis process of Example 1, wherein the weight ratio of morpholine hydrochloride solution and propionaldehyde is 3-5, and the temperature of propionaldehyde dropping is 35-40℃, and the residue in the kettle after atmospheric distillation The morpholine hydrochloride solution was used as the catalyst for the next reaction to be recycled 22 times. Before the next cycle, the pH value was adjusted to 2-3, and the products obtained after each reaction were sampled and tested by LC / MS. The yield, selectivity and purity of methacrolein are obtained. The experimental data are shown in Table 3.

[0038] Table 3 Test results of trimethacrolein products in Example

[0039]

[0040] From the above data, it can be seen that before the morpholine hydrochloride solution was used 22 times, the yield of methacrolein was above 97%, and the purity was above 97%. However, the indicators began to decrease from the 22nd test. It can be seen that the morpholi...

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Abstract

The invention discloses a synthetic process of methylacrolein. The synthetic process is characterized in that the methylacrolein is synthesized by adopting paraformaldehyde and propionaldehyde under the condition of taking a morpholine hydrochloride solution as a catalyst, and controlling the reaction temperature and the proportion of all reactants. The methylacrolein synthesized by adopting the process has the yield of 97 percent or more, the purity is equal to or greater than 97 percent and the selectivity is close to 100 percent; meanwhile, the catalyst can be recycled for 20 times or more at least; the problems that the yield and the selectivity cannot be combined, the recycling of the catalyst is poor, and the methyla crolein quality is poor in a traditional method are solved.

Description

Technical field [0001] The invention relates to the field of organic synthesis, in particular to a synthesis process of methacrolein. Background technique [0002] Methacrolein, also known as methacrolein, is a colorless liquid with a strong irritating odor, boiling point 68℃, melting point -81℃, density 0.85, slightly soluble in water, soluble in ethanol and ether, with conjugated double bonds It can be used as a good reactant for Diels-Alder reaction. Methacrolein is an important chemical intermediate for the preparation of methacrylic acid, methyl methacrylate, thermoplastic monomers and a variety of spices and pharmaceutical intermediates. The structure is as follows: [0003] [0004] The synthesis mainly includes the following process routes: isobutene (tert-butanol) catalytic oxidation method, isobutane direct oxidation method, formaldehyde and propionaldehyde condensation method, etc. The oxidation method has cheap raw materials, but the reaction process is complicated and...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C47/22C07C45/75
CPCY02P20/584C07C45/75B01J31/0244B01J2231/342C07C45/82C07C47/22
Inventor 李永红李良龙曾林久吴高强黄凤马妙玲贺显伟黄宗凉陈军李波廖英黄建军
Owner 成都建中香料香精有限公司
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