[maakii]

Hi!

I recently did a lab and I'm a little confused  It was on the reduction of 4-t-butylcyclohexanone (dissolved in methanol) to 4-t-butylcyclohexanol using sodium borohydride. The quenching step used NH4Cl and when NH4Cl was added to the completed reaction mixture containing the alcohol, a white ppt was formed which then dissolved when ethyl acetate was added. what is this white ppt?

Also how does NH4Cl quench the reaction? I'm not very sure but i think it protonates the O- of the alcohol and also destroys the BH4- ions?

And if LiAlH4 was used instead, what conditions need to be changed? Other than using ether as a solvent are there any other considerations that need to be made?

Thank you!! 

[OC pro]

The white precipitate was product!!! It does not dissolve well in water but superb in ethyl acetate...
Did you inform yourself properly before doing the reaction?

[SirRoderick]

Well if you don't know what it is you're trying to produce, you need to prepare better.

[royal1103]

In my opinion, the white precipitate is the product, you can analyse it through TLC or MS.
Second, NH4Cl is Louis acid, it can react with NaBH4, which has basicity.
And third, LiAlH4 has stonger reductive than NaBH4, and it's much more expensiver. So I don't think it's a good idea to substitute  NaBH4 with LiAlH4, while NaBH4 could make the reaction .