Question

by which method impure glycerien can be purified

Answer 1

Glycerin is a 3-carbon alcohol, aka glycerol. It is non-volatile and intensely hygroscopic (water-loving), and can be rinsed off any surface with ordinary water.

Pure glycerin has recently been found to hasten cell maturation and suppress inflammation. Glycerin is a major component of numerous expensive soaps. Glycerin is produced in huge quantities in its impure form as a byproduct of bio fuel generation. This crude form is treated mostly as a waste product and is generally disposed of or burned.

The liquids which decompose at its boiling point can be purified by vacuum distillation. Glycerol which decomposes at its boiling point can be distilled without decomposition at 453K under 12mm Hg pressure.