A rotary evaporator (rotary evaporator) is a device for the rapid removal of liquids by distillation of them under reduced pressure [1] . It is widely used in chemical laboratories for evaporation of solvents from mixtures of substances, as well as for the separation of liquids.
Content
- 1 History
- 2 Device
- 3 Principle of work
- 4 notes
- 5 Literature
- 6 References
History
The rotary evaporator was first proposed by the American biochemist Lyman C. Craig in 1950, after which modifications and improved designs were immediately offered, and in 1957 Walter Büchi from Basel launched the first commercial copy rotary evaporator. In the early 1960s, a rotary evaporator became a common tool in chemical laboratories [2] .
Device
The rotary evaporator consists of a glass tube with a thin section , to which a round-bottom flask A is attached, heated by a water bath B. Engine C rotates the flask, and the solvent vapor enters the reflux condenser F , where it is cooled and condensed, flowing into the receiving flask G. Parts of the rotary evaporator can be further secured with a tripod D and foot E. To quickly release the vacuum in the system, a valve H is provided, which is also often used to inert gas ( argon or nitrogen ) into the system.
Principle of Operation
The action of a rotary evaporator is based on lowering the boiling point of the solvent by creating a reduced pressure in its system using a water-jet or vacuum pump . This approach allows you to remove the solvent from the solution at a lower temperature, avoiding the side reactions that can occur when the mixture is heated [3] [4] [5] .
Solvent evaporation occurs from a thin film on the inside of the flask. Due to the rotation of the flask, this surface is constantly updated, which significantly increases the evaporation rate [5] . By rotating the flask, effective mixing of the solution is also achieved, reducing the likelihood of it being thrown out of the flask. Heating with a water bath increases the vapor pressure of the solvent and also accelerates evaporation. The rotation speed and heating force are usually controlled using the controls of a rotary evaporator [6] .
As the solvent evaporates, its vapor condenses on the refrigerator and flows into the receiver flask. If the cooling is sufficiently effective, then almost all evaporated solvent can be collected in the receiver. In this case, the dissolved substance remains in the flask from which evaporation occurs [6] .
| Solvent | T. bale., ° C (760 mmHg) | T. boiling., ° C (40 mm RT. Art.) |
|---|---|---|
| acetonitrile | 81.8 | 7.7 |
| water | one hundred | 34.0 |
| hexane | 68.7 | –2.3 |
| heptane | 98.4 | 22.3 |
| diethyl ether | 34.6 | –27.7 |
| methanol | 64.7 | 5,0 |
| ethanol | 78,4 | 19 |
| ethyl acetate | 77.1 | 9.1 |
Notes
- ↑ Sharp, 1993 , p. 73-76.
- ↑ Jensen WB The Origin of the Rotavap // J. Chem. Educ. - 2008 .-- Vol. 85 , no. 11 . - P. 1481 . - DOI : 10.1021 / ed085p1481 .
- ↑ 1 2 Bacher .
- ↑ University of Toronto Scarborough .
- ↑ 1 2 Workshop on Organic Chemistry / Ed. N. S. Zefirova. - M: Binom. Laboratory of Knowledge, 2010. - P. 32. - ISBN 978-5-94774-942-7 .
- ↑ 1 2 Pavia DL Introduction to Organic Laboratory Techniques: A Small-scale Approach . - Cengage Learning, 2005 .-- S. 643.
Literature
- Sharp J., Gosni I., Rowley A. Workshop on Organic Chemistry = Practical Organic Chemistry / Per. from English V.A. Pavlova, under the editorship of V.V. Moscow. - M: Mir, 1993. - ISBN 5-03-002126-4 .
Links
- Wikimedia Commons has media related to Rotary Evaporator
- Bacher AD How to use a Rotary Evaporator . Date of treatment May 20, 2013. Archived May 23, 2013.
- University of Toronto Scarborough. Rotary Evaporation . Date of treatment May 20, 2013. Archived May 23, 2013.