Method for preparing Grignard reagent

A Grignard reagent and Grignard reaction technology, which is applied in the field of Grignard reagent preparation, can solve the problems of deterioration, Grignard reagent contact with air, etc., and achieve the effects of improving utilization rate, facilitating recycling, and improving quality

Active Publication Date: 2011-06-15
ZHEJIANG NHU CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Every time the metal magnesium powder is fed and discharged, the Grignard reagent will be partially deteriorated due to contact with the air, and there is a great potential safety hazard.

Method used

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  • Method for preparing Grignard reagent
  • Method for preparing Grignard reagent

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Experimental program
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Effect test

Embodiment 1

[0020] exist figure 1 In the external circulation Grignard reagent preparation device, the reaction equipment is a reaction kettle 9 and a magnesium ingot tower 1 connected in series with it, and large-grained magnesium or magnesium ingots 5 are placed in the magnesium ingot tower 1, and the magnesium ingot tower 1 is provided with for supporting large The support plate 6 of granular magnesium or magnesium ingot and the filter element 7 located under the support plate, the magnesium ingot tower has a jacket 4 outside, add solvent and initiator to the reaction kettle for Grignard reaction, and the liquid filtered by the filter element flows into the reaction kettle 9, the liquid coming out of the bottom of the reaction kettle is pumped back into the magnesium ingot tower with a circulation pump 10, and the liquid is sprayed to large-grained magnesium or magnesium ingots through the distributor 2 located at the upper part of the magnesium ingot tower. Feeding port 3 below the di...

Embodiment 2

[0027] exist figure 2 In the kettle reaction Grignard reagent preparation device (the reaction kettle volume is 500L). Magnesium is in a static state, and stainless steel wire mesh is used to make a net bag 11 and fixed on the wall of the reaction kettle 12. The magnesium is placed in the net bag, and the mesh hole diameter of the net bag is ≤5mm.

[0028] The specific preparation method is as follows: put 200Kg (10*10*20) of metal magnesium particles into the magnesium fixed net bag around the reaction kettle by using the feeding pipe in advance, put 95L of tetrahydrofuran into the reaction kettle by using vacuum, and add 0.12Kg of iodine as an initiator. Nitrogen replacement was carried out in the reactor. After replacement, close the drain port. Open the jacket of the reaction kettle to heat the steam, adjust the steam pressure to 0.05MPa, perform slow heating, adjust the steam pressure, and control the temperature inside the kettle at 80-90°C. The mixed liquid of 40Kg ...

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Abstract

The invention discloses a method for preparing a Grignard reagent. In the conventional method for preparing the Grignard reagent by using magnesium powder, the magnesium content of the common magnesium ingot can reach over 99 percent; after the magnesium ingot forms the magnesium powder by cutting processing, the magnesium content of the magnesium powder is about 95 percent; 4 percent of metal magnesium is oxidized during the cutting processing; an oxidation film of the oxidized magnesium can delay the occurrence of a Grignard reaction to cause initiation difficulty; and if the dropping speed of halogenated hydrocarbon is increased, instant reaction is generated to release a great deal of reaction heat and a production accident occurs. The method for preparing the Grignard reagent is characterized in that: large-particle magnesium or magnesium ingot with nominal diameter of more than 1 mm serves a raw material; and the Grignard reaction is performed in a kettle reaction mode or an external circulation reaction mode. The large-particle magnesium or magnesium ingot serves the raw material, so the quantity of magnesium oxide in the magnesium is greatly reduced, proportion of byproducts formed by the magnesium oxide and an initiator is reduced, the quality of the Grignard regent is improved, and utilization ratio of the metal magnesium and utilization ratio of the halogenated hydrocarbon are increased.

Description

technical field [0001] The invention relates to reagents in the field of chemistry, in particular to a method for preparing Grignard reagents. Background technique [0002] Grignard reagent is a commonly used chemical reagent, and its usual preparation method is: put magnesium powder into the reactor, add reaction solvent ether, THF, methyltetrahydrofuran, toluene or a mixture thereof, add initiator; after nitrogen replacement, Raise the temperature to a suitable reaction temperature, add the halogenated hydrocarbon or the mixture of the halogenated hydrocarbon and the solvent dropwise; after the dropwise addition, keep the temperature, and cool to obtain a qualified Grignard reagent. This preparation method has a big drawback: the utilization rate of magnesium is low. The magnesium content in ordinary magnesium ingots can reach more than 99%, but after magnesium ingots are processed into magnesium powder by cutting, the magnesium content in magnesium powder is only about 9...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07F3/02B01J19/18
Inventor 张谦吴再红石泽宇潘永君严辉冯仪红
Owner ZHEJIANG NHU CO LTD
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