saps
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Registered: 7-3-2005
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Lithium Triethyl Borohydride Synthesis
Over the past few days I have been working on developing a method for the production of various borate esters in order to use them for the production
of boronic acids and various strong ruducing agents such as Lithium Triethyl Borohydride which has the following chemical formula.
Li(CH3CH2)3BH
In order for me to make the chemical Li(CH3CH2)3BH I need to prepare the
Triethyl Borate ester through an H3O+ catalyzed esterification reaction in which orthoboric acid and ethanol react to loose water molecules. I have
allready synthesized the ester but I have had major difficulties in separating it from the mixture as it is produced due to the fact that the ester
boils at about 120 degrees celcius and the EtOH boils around 87 degrees celcius. So I will be distilling off impure EtOH/ Triethyl Borate ester
mixtures that will be fractionated and dried later on in order to remove any unwanted water molecules
When I have finally Purified the triethyl borate ester I plan on reacting it with LiH under inert N2 gas to produce Lithium Triethyl Borohydride. Here
is the following chemical reaction that will take place:
4LiH + B(CH3CH20)3 ----> Li(CH3CH2)3BH + 3LiOH
One of My main reasons for posting this is to get other individuals input and secondly because I am wondering what type of drying agent would be most
suitable for removing unwanted H2O from the purified triethyl borate ester without decomposing it or innitiating base catalyzed hydrolysis. This ester
is pretty unstable. I have found that its vapors break down to the origional reactants on contact with air.
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praseodym
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| Quote: | Originally posted by saps
I am wondering what type of drying agent would be most suitable for removing unwanted H2O from the purified triethyl borate ester
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Why is it a problem to use CaCl2 as the drying agent in this case? I dont see a problem in using CaCl2...
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Eclectic
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4LiH + (CH3CH2O)B -> LiBH4 +3LiOCH2CH3
LiH + (CH3CH2)3B -> LiBH(CH2CH3)3
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