Distilland
Definition and meaning of Distilland in chemistry.
Distilland is the liquid mixture charged into a still or distillation flask that is to be separated by distillation, as distinguished from the distillate (the vapor condensed and collected) and the residue (the less volatile material left behind).
In more detail
During distillation, the distilland is heated in the pot or boiling flask so that its more volatile components vaporize preferentially; these vapors travel up a column or through a condenser and are collected as distillate, while less volatile components stay behind as residue. The term follows the same "-and" pattern as titrand (the solution being titrated), naming the starting material rather than the product. Using distinct terms for the feed mixture, the collected vapor product, and the leftover residue avoids ambiguity when describing simple, fractional, or steam distillation setups.
Key facts
| Field | General Chemistry |
|---|---|
| Role | Starting mixture placed in the still |
| Contrast | Distillate (vapor product) and residue (bottoms) |
| Related term | Analogous to "titrand" in titration |
In fractional distillation of crude oil, the crude oil itself is the distilland, while gasoline, kerosene, and diesel are among the distillates collected at different boiling-point ranges.
Frequently asked questions
Is distilland the same as distillate?
No. The distilland is the original mixture loaded into the still before heating; the distillate is the vapor that has been condensed and collected as it leaves the still.
Why isn't the whole distilland converted to distillate?
Because distillation separates based on relative volatility, not all components vaporize; less volatile material remains behind as the residue, so only part of the distilland typically becomes distillate.