what is difference between rectified spirit and absolute alcohol
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Rectified spirit or rectified alcohol is high concentration alcohol
purified by the process of rectification (repeated or fractional
distillation). It is used for medicinal purposes, as a household
solvent, and in mixed drinks. Neutral grain spirit is a kind of
rectified spirit, produced from grain.
Rectified alcohol is illegal for non-medical purposes in several countries such as India, though not in most developed world countries where even where it was illegal, as in Canada, there has recently been a change in policy.
Absolute or anhydrous alcohol generally refers to purified ethanol, containing no more than one percent water.
It is not possible to obtain absolute alcohol by simple fractional distillation, because a mixture containing around 95.6% alcohol and 4.4% water becomes a constant boiling mixture (an azeotropic mixture). In one common industrial method to obtain absolute alcohol, a small quantity of benzene is added to rectified spirit and the mixture is then distilled. Absolute alcohol is obtained in third fraction that distills over at 78.2 °C (351.3 K).
Because a small amount of the benzene used remains in the solution, absolute alcohol produced by this method is not suitable for consumption as benzene is carcinogenic.
There is also an absolute alcohol production process by desiccation using glycerol. Alcohol produced by this method is known as spectroscopic alcohol - so called because the absence of benzene makes it suitable as a solvent in spectroscopy.
Currently, the most popular method of purification past 95.6% purity is desiccation using adsorbents such as starch or zeolites, which adsorb water preferentially,. Azeotropic distillation and extractive distillation techniques also exist
Rectified alcohol is illegal for non-medical purposes in several countries such as India, though not in most developed world countries where even where it was illegal, as in Canada, there has recently been a change in policy.
Absolute or anhydrous alcohol generally refers to purified ethanol, containing no more than one percent water.
It is not possible to obtain absolute alcohol by simple fractional distillation, because a mixture containing around 95.6% alcohol and 4.4% water becomes a constant boiling mixture (an azeotropic mixture). In one common industrial method to obtain absolute alcohol, a small quantity of benzene is added to rectified spirit and the mixture is then distilled. Absolute alcohol is obtained in third fraction that distills over at 78.2 °C (351.3 K).
Because a small amount of the benzene used remains in the solution, absolute alcohol produced by this method is not suitable for consumption as benzene is carcinogenic.
There is also an absolute alcohol production process by desiccation using glycerol. Alcohol produced by this method is known as spectroscopic alcohol - so called because the absence of benzene makes it suitable as a solvent in spectroscopy.
Currently, the most popular method of purification past 95.6% purity is desiccation using adsorbents such as starch or zeolites, which adsorb water preferentially,. Azeotropic distillation and extractive distillation techniques also exist
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By Azeotrophic Distillation
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