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Preparation method of 1,1-diphenylethylene

A technology of diphenylethylene and acetophenone, which is applied in the field of preparation of 1,1-diphenylethylene, can solve the problems of loss of 1,1-diphenylethanol, unsuitability for industrialization, product loss, etc. The effect of obvious layer, wide practical value and mild conditions

Active Publication Date: 2014-04-30
ZHEJIANG UNIV OF TECH +1
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  • Abstract
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  • Claims
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Problems solved by technology

[0012] The method adopts a step-by-step method. First, 1,1-diphenylethanol is obtained through recrystallization, and then 1,1-diphenylethylene is obtained by reflux dehydration in glacial acetic acid. However, in the sulfuric acid hydrolysis process, some 1, Dehydration of 1-diphenylethanol to generate 1,1-diphenylethylene, and then obtaining pure product through recrystallization will inevitably cause a large loss of product, and experiments have proved that ethyl acetate is not suitable as a recrystallization solvent, recrystallization with ethyl acetate Crystallization, the loss of 1,1-diphenylethanol is serious, the yield is very low, and the last step of dehydration will produce more by-products, and it is difficult to obtain 1,1-diphenylethene through separation and purification, which is not suitable for industrialization

Method used

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  • Preparation method of 1,1-diphenylethylene

Examples

Experimental program
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Embodiment 1

[0034] Embodiment 1: the synthesis of phenylmagnesium bromide Grignard reagent

[0035]In a 500mL round bottom flask equipped with mechanical stirring, reflux condenser, dropping funnel, and thermometer, add 9.95g (0.41mol) of magnesium chips, 1.47g (0.008mol) of 1,2-dibromoethane, 65mL of anhydrous 2-Methyltetrahydrofuran, blow nitrogen, seal the device, raise the temperature to initiate the reaction, slowly add the 2-methyltetrahydrofuran solution of bromobenzene (containing 61.23g bromobenzene, 60mL of anhydrous 2-methyltetrahydrofuran), and raise the temperature to 60 °C, react for 4h. Take 1mL of the reaction solution and dilute it with 3mL of methanol as a sample. After GC detection: 0.9% bromobenzene, 98.7% benzene, and 0.2% biphenyl. GC detection conditions: gas phase column: SE-54 (50m), inlet sample temperature: 280°C, detector temperature: 280°C, carrier gas N 2 The flow rate is 2mL / min, and the temperature of the column oven is programmed: 100°C for 3 minutes, th...

Embodiment 2

[0036] Embodiment 2: the synthesis of phenylmagnesium bromide Grignard reagent

[0037] In a 500mL round bottom flask equipped with mechanical stirring, reflux condenser, dropping funnel, and thermometer, add 10.43g (0.43mol) of magnesium chips, 2.93g (0.016mol) of 1,2-dibromoethane, 65mL of anhydrous 2-Methyltetrahydrofuran, blow nitrogen, seal the device, raise the temperature to initiate the reaction, slowly add 2-methyltetrahydrofuran solution of bromobenzene (containing 61.23g bromobenzene, 60mL of anhydrous 2-methyltetrahydrofuran), and raise the temperature to 80 ℃ reaction 2h. A small amount of reaction solution was diluted with methanol and tested by GC: 0.5% bromobenzene, 99.1% benzene, and 0.2% biphenyl. The reaction solution dilution method and GC detection conditions are the same as in Example 1.

Embodiment 3

[0038] Embodiment 3: the synthesis of phenylmagnesium bromide Grignard reagent

[0039] In a 500mL round bottom flask equipped with mechanical stirring, reflux condenser, dropping funnel, and thermometer, add 9.95g (0.41mol) of magnesium chips, 1.22g (0.008mol) of bromobenzene, and 65mL of anhydrous 2-methyltetrahydrofuran, Nitrogen was blown, the device was sealed, and the temperature was raised to initiate the reaction. The solution of bromobenzene in 2-methyltetrahydrofuran (containing 60.01 g of bromobenzene and 60 mL of anhydrous 2-methyltetrahydrofuran) was slowly added dropwise, and the temperature was raised to 60°C for 4 hours after the drop. A small amount of the reaction solution was diluted with methanol and tested by GC: 0.8% bromobenzene, 98.8% benzene, and 0.2% biphenyl. The reaction solution dilution method and GC detection conditions are the same as in Example 1.

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Abstract

The invention discloses a preparation method of 1,1-diphenylethylene shown in a formula (V). The method comprises the steps of firstly carrying out reaction on bromobenzene and magnesium chips in anhydrous 2-methyltetrahydrofuran to obtain a phenylmagnesium bromide Grignard reagent, and then dripping acetophenone into the phenylmagnesium bromide Grignard reagent to react, so as to generate 1,1-diphenylethanol; finally, dewatering 1,1-diphenylethanol in the presence of a sulfoacid functional ionic liquid catalyst, so as to obtain 1,1-diphenylethylene shown in the formula (V). The preparation method disclosed by the invention is short in reaction step, mild in condition, simple and convenient to operate, high in product yield, low in production cost, friendly to environment, and applicable to industrial production.

Description

(1) Technical field [0001] The present invention relates to a preparation method of 1,1-diphenylethylene, in particular to a one-pot method for preparing 1,1-diphenylethylene by using acetophenone and phenylmagnesium bromide Grignard reagent as raw materials in solvent 2-methyltetrahydrofuran. 1-diphenylethylene method. (2) Background technology [0002] 1,1-Diphenylethylene is a very useful pesticide and pharmaceutical intermediate, it is an important intermediate of the safener isoxadifen, and the safener isoxadifen is a widely used pesticide in the field of pesticides The antidote used can not only improve the drug resistance of crops, but also can be used to solve the problem of controlling difficult weeds, expanding the application range and effectiveness of herbicides. In medicine, it can undergo 1,3-dipolar cycloaddition reaction with nitrone to generate oxazole products, which is an important intermediate for the synthesis of oxazole drugs. In the field of polymer ...

Claims

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Application Information

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IPC IPC(8): C07C15/50C07C1/32
CPCY02P20/52
Inventor 陈志卫苏为科井蕾黄生建陈炯明梁旭华
Owner ZHEJIANG UNIV OF TECH
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