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Method for catalyzing alkylation reaction by using phase transfer

An alkylation reaction and phase transfer catalyst technology, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc., can solve the problems of increased separation difficulty, long reaction time and high temperature, and achieve simplified post-treatment process, The effect of lowering the reaction temperature and shortening the reaction time

Inactive Publication Date: 2021-04-09
QINGDAO UNIV OF SCI & TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the aftertreatment after the reaction is complicated and requires steps such as precipitation, extraction, and layering. After the precipitation, the polar solvent (such as acetone, DMF, etc.) mostly azeotropes with water, which increases the difficulty of separation.
And the reaction time is long, the temperature is high, and the yield is low

Method used

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  • Method for catalyzing alkylation reaction by using phase transfer
  • Method for catalyzing alkylation reaction by using phase transfer
  • Method for catalyzing alkylation reaction by using phase transfer

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0020] The chemical reaction equation that o-methylphenylacetic acid prepares methyl bromophenylacrylate is as follows,

[0021]

[0022] The one-step original process of methylation reaction is as follows:

[0023] Dissolve the acylate in acetone, add metered dimethyl sulfate, potassium carbonate (or KOH), stir, heat and reflux for 3 hours, cool and filter, precipitate, extract with dichloromethane, wash the organic phase, dry, filter, and remove dichloromethane to obtain a yellow liquid , The yield is about 85%.

[0024] In the technology provided by the invention as follows:

[0025] In the acylate dichloromethane solution after the above reaction, directly add a phase transfer catalyst with a mass ratio between 1% and 2%, and then add 40-50% KOH aqueous solution dropwise. Add dimethyl sulfate, then raise the temperature to room temperature, trace the reactants drop by drop within 0.5-1h until the reaction is complete, add a certain amount of water and let stand to sep...

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Abstract

The invention discloses a method for catalyzing alkylation reaction by using phase transfer. The method comprises alkylation reaction which is carried out in a non-polar solvent, and when the alkylation reaction is carried out, a phase transfer catalyst and concentrated alkali are added, and then dimethyl sulfate is dropwise added, wherein the phase transfer catalyst is quaternary ammonium salt or polyethylene glycol, the addition amount of the phase transfer catalyst is 1%-10% of the mass of reactants, the concentration of the added liquid caustic soda is 30%-50%, and the concentrated alkali is KOH or NaOH. In the implementation process of the method, the reaction yield can be improved, the reaction temperature is reduced, the reaction time is shortened, and the post-treatment process is simplified.

Description

technical field [0001] The invention belongs to the technical field of chemical industry, in particular to a method for using phase transfer catalyzed alkylation reaction. Background technique [0002] Dimethyl sulfate is a methylation reagent commonly used in chemical production, and is mostly used in the alkylation reaction in chemical products such as pharmaceuticals, pesticides, and dyes. [0003] Although dimethyl sulfate is highly toxic, it is still the first choice of methylating reagent due to its high reactivity and low price. [0004] Adopt polar solvent to add strong base (KOH, NaOH) drop-wise dimethyl sulfate in reaction process and react. However, the aftertreatment after the reaction is complicated and needs to go through working steps such as precipitation, extraction, and layering, and the separation difficulty is increased because most of the polar solvents (such as acetone, DMF, etc.) are azeotropic with water after the precipitation. And the reaction tim...

Claims

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Application Information

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IPC IPC(8): C07C67/307C07C69/734
CPCC07C67/08C07C67/343C07C67/30C07C67/307C07C69/614C07C69/732C07C69/734
Inventor 田泊凝赵加恩宋双骐赵佳睿耿赛
Owner QINGDAO UNIV OF SCI & TECH
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