The preparation method of dibutylmagnesium
Technical field
The present invention relates to a kind of is the preparation method of the synthetic dibutylmagnesium of raw material with Sec-Butyl Chloride, magnesium powder, n-Butyl Lithium.
Background technology
Organic halogenation magnesium is that Grignard reagent has application very widely in chemical reaction.Tong Geshi reagent is compared, and dialkyl magnesium reaction is similar and use and want much less with organic halogenation magnesium.Its major cause is also not have suitable method mass production dialkyl magnesium up to now.Dialkyl magnesium compare with Grignard reagent and lithium alkylide have that raw materials cost is low, transportation easily.Particularly dialkyl magnesium has the excellent in chemical performance, compares dialkyl magnesium with lithium alkylide and has better thermostability and weak igniting property (ethereal solution).Dialkyl magnesium even can be used for the stablizer of lithium alkylide hydrocarbon solution.Compare with organic halogenation magnesium, dialkyl magnesium stability in varsol is stronger, and reaction yield is higher.Dialkyl magnesium is similar to lithium alkylide, can be used as the metallization reagent of organic compound, as benzene, toluene etc., can also react with unsaturated organic compound.
Dibutylmagnesium, English name: Dibutylmagnesium (being called for short DBM) has multiple isomers.Be dissolved in ethers, pure dibutylmagnesium is nonvolatile solid, but since its solid very easily fire, so finished product is made 14% hexane solution or 17% n-heptane solution.
Dibutylmagnesium is because the defective on the preparation method never has the such widespread use of Grignard reagent.Preparation method is the earliest reduced and gets by the magnesium powder by mercury alkylide, and its reaction is as follows:
R
2Hg+Mg→R
2Mg+Hg
This preparation process be subjected to the great number price of mercury and when using injury two aspects to human body limit.In fact generally speaking, mercury alkylide is made by magnesium exactly.This reaction generally will be carried out in alkaline environment, must compare under the environment of alkali-free in the Grignard reagent combined reaction with it, and it can decompose more alkyl magnesium.
Secondly by adding diox itself and magnesium halide are separated out with the form of complex compound, react as follows:
2RMgX+C
4H
8O
2→R
2Mg+C
4H
8O
2·MgX
2
Make this reaction under alkali free environment, not finish because diox itself is alkalescence, therefore,, make its production be subjected to great restriction because dibutylmagnesium preparation difficulty has mercury pollution and must finish under alkaline environment.
Summary of the invention
Technical problem to be solved by this invention is the deficiency that exists at above-mentioned prior art and a kind of dibutylmagnesium preparation method is provided, it have simple for process, pollution-free, cost is low, magnesium powder transformation efficiency and the high advantage of product yield.
The present invention for the technical scheme that problem adopted of the above-mentioned proposition of solution is:
With Sec-Butyl Chloride, magnesium powder, n-Butyl Lithium is raw material, synthetic dibutylmagnesium under anhydrous, anaerobic solvent condition, and its reaction process comprises: at N
2Protection mixes magnesium powder, initiator down, places the reactor heating, stirs, and slowly add a small amount of Sec-Butyl Chloride solution, after the initiation reaction, under the insulation situation, Sec-Butyl Chloride solution is slowly added reactor, and reaction generates Grignard reagent CH
3CH
2CH (CH
3) MgCl; Cool, add the n-Butyl Lithium hexane solution fast, after the insulation reaction, fractionation by distillation goes out solvent, and cold filtration prepares dibutylmagnesium; Each proportion of raw materials is in the preparation process: magnesium powder: Sec-Butyl Chloride: the mol ratio of n-Butyl Lithium is 1.0~1.2: 1: 1.
Press such scheme, described initiator is I
2, Br
2, methyl iodide, monobromethane or Grignard reagent; The add-on of described initiator is 0.1~0.5% of Sec-Butyl Chloride institute consumption by weight.
Press such scheme, described reactor is to have in the reactor of stirring, reflux exchanger, nitrogen ingress pipe, dropping funnel, and reaction process feeds nitrogen.
Press such scheme, after reaction causes, Sec-Butyl Chloride solution is slowly dropped in the reactor, temperature of reaction is controlled at 30 ℃~100 ℃; After dropwising, continue to stir insulation reaction 1.5~3 hours.
Press such scheme, after generating Grignard reagent, cool, under 0 ℃~60 ℃ temperature, add the n-Butyl Lithium hexane solution fast, insulation reaction 1~2 hour, holding temperature are controlled at 30 ℃~120 ℃.
Press such scheme, described Sec-Butyl Chloride solution is formulated by Sec-Butyl Chloride and solvent, and strength of solution is 0.6~1.05mol/L, and described solvent is an ether, or is in tetrahydrofuran (THF), benzene, toluene, the normal hexane any one.
Press such scheme, described n-Butyl Lithium hexane solution is formulated by n-Butyl Lithium and solvent normal hexane, and the volumetric molar concentration of solution is 2.5mol/L.
Press such scheme, fractionation by distillation goes out solvent, gets supernatant liquid after leaving standstill; The little metal lithium is cut into small pieces adds in the above-mentioned supernatant liquor, slowly stir, the inflated with nitrogen protection leaches the unreacted metal lithium, and the concentration with complexometry analysis dibutylmagnesium adds normal hexane, is made into certain density dibutylmagnesium solution.The solvent of collecting can be recycled.
The interior stirring velocity of reactor is 100~700 rev/mins in the above-mentioned reaction; Require anhydrous, anaerobic in the reactor, and the inflated with nitrogen protection.
Reaction formula of the present invention is:
CH
3CH
2CH(CH
3)Cl+Mg——CH
3CH
2CH(CH
3)MgCl
CH
3CH
2CH(CH
3)MgCl+CH
3CH
2CH
2CH
2Li——CH
3CH
2CH
2CH
2Mg(CH
3)CHCH
2CH
3
CH
3CH
2CH(CH
3)Cl+2Li——CH
3CH
2CH(CH
3)Li+LiCl
CH
3CH
2CH(CH
3)Li+CH
3CH
2CH(CH
3)MgCl——[CH
3CH
2CH(CH
3)]
2Mg+LiCl
The Grignard reagent synthetic causes slower, should carry out under heating and slow stirring condition.Reaction is reacted rapider, and is attended by a large amount of reaction heat after causing, and following side reaction easily takes place:
CH
3CH
2CH(CH
3)Cl+2Mg——CH
3CH
2CH(CH
3)CH(CH
3)CH
2CH
3+MgCl
2
The way that solves has: (1) cooling, the reactor of use should be equipped with the cooling heat transferring device, accelerates to stir, and makes the reaction mixture uniform mixing, avoids local superheating, guarantees to react and effectively carries out.(2) Sec-Butyl Chloride and solvent ether are hybridly prepared into the solution of lower concentration, slowly join in the reactor control speed of reaction.
The reaction of Grignard reagent and butyllithium reaction generation dibutylmagnesium is very fast, and reaction is very complete.In order to increase the LiCl particle grain size, be easy to separate, need to reduce temperature of reaction and stirring velocity.The LiCl that separates can recycle, and reduces production costs the enabling environment protection.
Beneficial effect of the present invention is: 1, adopt two-step approach to finish preparation process, preparation process is simple and effective; 2, preparation cost is low, and is pollution-free, the enabling environment protection; 3, magnesium powder transformation efficiency and product yield height, and the solvent of collecting can be recycled.
Embodiment
Further specify the present invention by the following examples.
Embodiment 1:
To agitator, dropping funnel, thermometer, nitrogen ingress pipe are housed, feed nitrogen in the 250ml four-hole boiling flask reactor of reflux exchanger (on adorn drying tube), water vapour is driven away in heating, removes thermal source after reaching 100 ℃.When treating that temperature drops to about 70 ℃, add 3.65g (0.15mol) magnesium powder, 2g2-chlorobutane, 30mL ether and an iodine, slowly stir, make that material is stable in the reactor refluxed 10~20 minutes, controlled temperature is about 34 ℃.In the reactor liquid become brown, treat that reddish-brown is taken off after, beginning slowly drips Sec-Butyl Chloride solution, Sec-Butyl Chloride solution is mixed by 15g2-chlorobutane and 110mL ether; Control reaction temperature after dropwising, continued stirring reaction 3 hours at 33 ℃~35 ℃, added the hexane solution that 60mL contains the 2.5mol/L n-Butyl Lithium then in reactor fast, reduced stirring velocity, and control reaction temperature is 0 ℃~5 ℃.React the filtering separation that finishes, filtrate is analyzed Mg content with EDTA (complexometry), and calculating product yield is 85%.
Embodiment 2:
To agitator, dropping funnel, thermometer, nitrogen ingress pipe are housed, feed nitrogen in the 250ml four-hole boiling flask reactor of reflux exchanger (on adorn drying tube), water vapour is driven away in heating, removes thermal source after reaching 100 ℃.When treating that temperature drops to about 70 ℃, add 3.65g (0.15mol) magnesium powder, 2g2-chlorobutane, 30mL normal hexane and an iodine, slowly stir, controlled temperature is about 65 ℃.Liquid becomes rose in the bottle, treats that rose takes off, and slowly drips Sec-Butyl Chloride solution, and Sec-Butyl Chloride solution is mixed by 15g2-chlorobutane and 110mL normal hexane; Temperature of reaction is controlled at 60 ℃~68 ℃, continues stirring reaction 3 hours, adds the hexane solution that 60mL contains the 2.5mol/L n-Butyl Lithium then in reactor fast, reduces stirring velocity, and control reaction temperature is 0 ℃~5 ℃.React the filtering separation that finishes, filtrate is analyzed Mg content with EDTA, and calculating product yield is 75%.
Embodiment 3:
To agitator, dropping funnel, thermometer, nitrogen ingress pipe are housed, feed nitrogen in the 250ml four-hole boiling flask reactor of reflux exchanger (on adorn drying tube), water vapour is driven away in heating, removes thermal source after reaching 100 ℃.When treating that temperature drops to about 70 ℃, add 4.4g (0.18mol) magnesium powder, 3g2-chlorobutane, 100mL ether and iodine, slowly stir, controlled temperature is about 33 ℃.Liquid becomes reddish-brown in the bottle, treats that reddish-brown takes off, and slowly drips Sec-Butyl Chloride solution, and Sec-Butyl Chloride solution is mixed by 14g2-chlorobutane and 160mL ether.Temperature of reaction is controlled at 33 ℃~35 ℃, continues stirring reaction 3 hours, adds the hexane solution that 60mL contains the 2.5mol/L n-Butyl Lithium then in reactor fast, reduces stirring velocity, and control reaction temperature is 0 ℃~5 ℃.React the filtering separation that finishes, filtrate is analyzed Mg content with EDTA, and calculating product yield is 76%.
Embodiment 4:
To agitator, dropping funnel, thermometer, nitrogen ingress pipe are housed, feed nitrogen in the 250ml four-hole boiling flask reactor of reflux exchanger (on adorn drying tube), water vapour is driven away in heating, removes thermal source after reaching 100 ℃.When treating that temperature drops to about 70 ℃, add 4.9g (0.2mol) magnesium powder, 2g2-chlorobutane, 30mL normal hexane and an iodine, slowly stir, controlled temperature is about 65 ℃.Liquid becomes rose in the bottle, treats that rose takes off, and slowly drips Sec-Butyl Chloride solution, and Sec-Butyl Chloride solution is mixed by 15g2-chlorobutane and 110mL normal hexane; Temperature of reaction is controlled at 60 ℃~68 ℃, continues stirring reaction 3 hours, adds the hexane solution that 60mL contains the 2.5mol/L n-Butyl Lithium then in reactor fast, reduces stirring velocity, and control reaction temperature is 0 ℃~5 ℃.React the filtering separation that finishes, filtrate is analyzed Mg content with EDTA, and calculating product yield is 76.6%.