Steam distillation is a special type of distillation (a separation process) for temperature sensitive materials like natural aromatic compounds. It once was a. This is the definition of steam distillation as the term is used in chemistry and engineering and a look at how it works to separate materials. The process of steam distillation separates the elements of a mixture through heating and evaporation, as different compounds usually have.
Distillation? Steam What Is
The arrow indicates a stopper used to close the system. Place large amount of plant material in a large round bottomed flask no more than half full , and just cover with water. If a steam line was used, be sure to drain the liquid from the steam trap before turning off the steam, to prevent back suction. Procedural summary of steam distillation. Steam Distillation Procedure A steam distillation apparatus is shown in Figure 5. A large amount of material is often necessary as the bulk of plants is cellulose, not oil.
Use an extension clamp to secure the large flask to the ring stand or latticework. If desired, further secure the setup with a platform e. Add water to the distilling flask to just cover the plant material. Two variations of steam distillation are regularly used: Although burners are not commonly used with the distillation of organic compounds, they are relatively safe in steam distillations because: To the top of the Claisen adapter, connect one of the following, depending on the variation of distillation used: If water will be heated in the distilling flask along with a burner: Attach a stopper to close the system indicated by the arrow in Figure 5.
Clamp and partially fill this separatory funnel with water Figure 5. If a steam line will be used: Insert a steam inlet tube, and position it so the outlet is just raised above the bottom of the flask. Connect this tube to a separatory funnel trap attached to the steam line Figure 5. The receiving flask can be a graduated cylinder, Erlenmeyer flask, or round bottomed flask.
Begin Distilling Begin heating the flask: If using a steam line, open the stopcock in the separatory funnel steam trap. Turn on the steam, and allow the water in the steam line to drain through the funnel and into a container Figure 5. Close the stopcock when it appears that most of what is coming out of the steam line is steam and not water.
Adjust the steam rate so that the steam bubbles vigorously through the liquid in the distilling flask Figure 5. The distillate will contain both water and oil, and may look one of two ways. A second layer may form, or the distillate may appear to have oily droplets clinging to the sides of the flask. This happens when the oil is very nonpolar e.
The distillate may also appear cloudy or "milky" Figure 5. A cloudy mixture forms when tiny insoluble particles are dispersed throughout the suspension. This tends to happen when the oil is water-insoluble but contains some polar functional groups e. Steam passes through the organic matter that contains the compounds for separation.
The steam condenses against that matter to form a mixture. That mixture gets heated further by more incoming steam, which continues to pass through the matter, evaporating the mixture. Due to the reduced vapor pressure, the required organic compounds also evaporate as a part of the mixture and are thus extracted from the organic matter. The evaporated mixture of steam and the organic compounds passes through jackets that have cold water coming in at one end.
The evaporated mixture then passes out as hot water from the other end after cooling the mixture down. This condenses the mixture, which is then collected and allowed to settle.
During the settling process, the extracted organic compounds come to the top, and they are then separated by filtering out the settled water from below. Alo is media director, chief writer and editor for a U.
He holds a bachelor's degree in business and communications. Alo's interests include business, investments, electronics, personal finance, health, communication, popular trends and travel. Related Sciencing Articles Types of Distillation. The Disadvantages of Simple Distillation. Examples of Evaporation and Distillation. What Is Anhydrous Methanol? Alo; Updated May 17, TL;DR Too Long; Didn't Read The process of steam distillation separates the substances of a mixture through evaporation, which then involves condensing the vapor back into liquid, taking advantage of the fact that different elements or compounds have different boiling points.
References New Mexico Tech University: Steam Distillation of a Spice University of Missouri:
5.5.D: Step-by-Step Procedures for Steam Distillation
Steam distillation. Definition: A method of separating mixtures based on differences in their volatilities in a boiling liquid mixture. The components in a sample. Aim: To obtain pure components from a mixture of organic compounds using steam distillation. Theory: Steam Distillation: This technique is used for separating. To: Separate substances which are: · Steam volatile and · Immiscible with water ( e.g. oil) We have a flask containing the liquid to be distilled. We heat the flask.