Method for preparing 4-methoxystyrene

A technology of methoxystyrene and methoxyphenyl, applied in the field of preparation of 4-methoxystyrene, can solve the problems of lack of high-purity products, unavoidable polymerization, inability to obtain high-purity products, etc. High purity, simple process, and the effect of solving harsh raw material requirements

Active Publication Date: 2015-03-25
华诺森(武汉)生物医药技术有限公司
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  • Summary
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AI Technical Summary

Problems solved by technology

In this method, when the pyrolysis elimination reaction occurs, the conversion rate is better, but it still cannot avoid the polymerization of the product in the pyrolysis tube, and the high-purity product cannot be obtained.
[0009] In summa

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0027] The invention provides a kind of preparation method of 4-methoxystyrene, comprises the following steps:

[0028] (1) Dissolve 4-methoxyacetophenone in ethanol with a volume fraction of 95%, stir, heat up, add reducing agent in batches for reduction reaction, the reaction temperature is 20-80°C, and the reaction time is 1- 3 h. After the reaction is finished, add water equal to the volume of ethanol, stir thoroughly, and remove excess reducing agent and the complex obtained by the reducing agent reaction. Then it was extracted with ethyl acetate, the layers were separated, the organic phase was dried and concentrated. Distillation with a distillation temperature of 90-110°C and a vacuum of 0-1 mmHg to obtain the intermediate 1-(4-methoxyphenyl)ethanol.

[0029] (2) Heat the oil bath to the set reaction temperature of 150-220°C in advance, then add potassium bisulfate and a small amount of 1-(4-methoxyphenyl)ethanol into the reaction flask, most of the 1- Add (4-methox...

Embodiment 1

[0038] a Reduction reaction: Add 2 kg of 4-methoxyacetophenone and 4 L of ethanol with a volume fraction of 95% into a three-neck flask with a capacity of 10 L. After heating to 30°C in a water bath, a total of 240 g of potassium borohydride was added in batches. After the addition, keep the temperature of the water bath constant, continue the reaction for 3 h, monitor by gas chromatography, after confirming that there is no 4-methoxyacetophenone remaining, add 4 L of tap water to terminate the reaction, stir for 45 min, and start the extraction. 4.5 L of ethyl acetate was added for the first extraction, and the remaining aqueous phase was extracted twice with 0.5 L of ethyl acetate. Combine the organic phases, add anhydrous sodium sulfate whose mass fraction is 5% of the mass of the organic phase, and dry for 3 h. After filtration, the filtrate was rotary evaporated to remove the solvent to obtain 1.993 kg of crude intermediate. Further distillation and purification (distil...

Embodiment 2

[0043] a Reduction reaction: Add 2 kg of 4-methoxyacetophenone and 4 L of ethanol with a volume fraction of 95% into a three-neck flask with a capacity of 10 L. After heating to 30°C in a water bath, 185 g of potassium borohydride was added in batches. After the addition, keep the temperature of the water bath constant, continue the reaction for 5 h, monitor by gas chromatography, after confirming that there is no 4-methoxyacetophenone remaining, add 4 L of tap water to terminate the reaction, stir for 45 min, and start the extraction. 4.5 L of ethyl acetate was added for the first extraction, and the remaining aqueous phase was extracted twice with 0.5 L of ethyl acetate. Combine the organic phases, add anhydrous sodium sulfate whose mass fraction is 5% of the mass of the organic phase, and dry for 3 h. After filtration, the filtrate was rotary evaporated to remove the solvent to obtain 1.996 kg of crude intermediate. Further distillation and purification (distillation temp...

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PUM

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Abstract

The invention relates to a method for preparing 4-methoxystyrene. The method comprises the following steps: (1) dissolving 4-methoxyacetophenone into an ethanol solvent, adding a reducer and performing reduction reaction to obtain an intermediate 1-(4-methoxyphenyl) ethanol; and (2) performing dehydration reaction on the intermediate obtained in step (1) under the catalysis of a dehydrating agent, and distilling at the same time to obtain a rough 4-methoxystyrene product. The method for preparing the 4-methoxystyrene is readily available in raw materials, simple in process, high in reaction yield and high in product purity, and a polymerization inhibitor is not needed, so that the problems that the requirement for raw materials is strict, the post treatment is difficult, polymerization is easily caused in the reaction, the production is discontinuous, the requirement for production equipment is strict and the like in the existing synthetic method are solved, and the method can be effectively applied to production practice.

Description

technical field [0001] The invention relates to the field of organic synthesis, in particular to a preparation method of 4-methoxystyrene. Background technique [0002] Styrenic compounds are important monomers for the synthesis of polystyrene resins. The substituents on the benzene ring can endow the polystyrene resins with various properties. They are widely used in materials, pharmaceutical intermediates, adhesives, Coatings, sunscreen and other fields. Both water and oil repelling properties of substituted polystyrene compounds are excellent. The polymer of p-methoxystyrene is an excellent anti-corrosion material, which is widely used in the information industry. There are many literature reports on its synthesis method, as follows. [0003] Patents DE2317525 and EP128984 provide a method for obtaining styrene through catalytic dehydrogenation reaction using ethylbenzene as a raw material. The disadvantages of this method are low yield, poor purity of the crude produc...

Claims

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Application Information

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IPC IPC(8): C07C43/215C07C41/18
CPCC07C41/18C07C41/26C07C43/23C07C43/215
Inventor 张爱军
Owner 华诺森(武汉)生物医药技术有限公司
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