Search results
Results from the WOW.Com Content Network
The solvent can be allowed to reflux over a drying agent housed in the still pot (shown as 2 in the figure) for a suitable time to dry solvent. The collecting tap (shown as 5 in the figure) can then be opened to collect the solvent in a Schlenk flask for storage. Depending on the boiling point of the solvent, a vacuum can be applied.
The concentration of solvent in water ranges from 40 to 80%. Higher boiling solvents have the advantage of a lower process pressure. This is weighed against the more difficult solvent recovery by distillation. [2] Ethanol has been suggested as the preferred solvent due to cost and easy recovery.
Short-path distillation is a distillation technique that involves the distillate traveling a short distance, often only a few centimeters, and is normally done at reduced pressure. [ 1 ] [ 2 ] Short-path distillation systems often have a variety of names depending on the manufacturer of the system and what compounds are being distilled within them.
The solvent is heated to reflux. The solvent vapour travels up a distillation arm, and floods into the chamber housing the thimble of solid. The condenser ensures that any solvent vapour cools, and drips back down into the chamber housing the solid material. The chamber containing the solid material slowly fills with warm solvent.
Extraction is a diffusion-based process, in which the solvent is required to diffuse into the matrix and the extracted material to diffuse out of the matrix into the solvent. Diffusivities are much faster in supercritical fluids than in liquids, and therefore extraction can occur faster.
The method of extractive distillation uses a separation solvent, which is generally non-volatile, has a high boiling point and is miscible with the mixture, but doesn't form an azeotropic mixture. The solvent interacts differently with the components of the mixture thereby causing their relative volatilities to change.
A binary distillation separates a feed mixture stream into two fractions: one distillate and one bottoms fractions. The principle for continuous distillation is the same as for normal distillation: when a liquid mixture is heated so that it boils, the composition of the vapor above the liquid differs from the liquid composition.
Diagram of a Batch Rectifier. The simplest and most frequently used batch distillation configuration is the batch rectifier, including the alembic and pot still.The batch rectifier consists of a pot (or reboiler), rectifying column, a condenser, some means of splitting off a portion of the condensed vapour (distillate) as reflux, and one or more receivers.