Question

at amide coupling:phe-ala dipeptide lab
use Boc-Phe-OH and
hcl-H-ala-Ome
and got BocPhe-Ala-Ome
at this experiment
i use Na2SO4
what's difference between na2so4 and mgso4
and why use na2so4. also explain why cannot use mgso4

Answer 1

Both sodium sulfate and magnesium sulfate are drying agents. We use these reagents to remove water from our reaction products. Magnesium sulfate is a fine powder. Since it is a fine powder it has large surface area and that make it a fast drying agent. Sodium sulfate is also a powder but not very fine powder like magnesium sulfate. Compared to sodium sulfate magnesium sulfate is more effective. Magnesium sulfate is very effective in ethereal solvents. Sodium sulfate is effective in ethereal solvents and other polar solvents as well.

Magnesium sulfate is slightly acidic in nature. In this case the product is dipeptide. So under acidic conditions it can undergo hydrolysis. That means if you use magnesium sulfate as drying agent your peptide will break down. That is why in these reactions sodium sulfate is using instead of magnesium sulfate.