Extraction according to Twisselmann

from Wikipedia, the free encyclopedia
Twisselmann extractor,
right: extraction sleeve

The extraction according to Twisselmann (DRP 519 371) is a continuous heat extraction and therefore a chemical-thermal separation processes .

properties

The Twisselmann extraction is similar to the Soxhlet extraction , but leads to a faster extraction and a stronger extraction of impurities. Like all extractions, it serves to separate two substances or groups of substances that are contained in a - often vegetable - product. Often it is a question of separating a fat or oil phase from dietary fibers such as fibers , cell walls or wood parts. This phase is continuously extracted from the sample by a heated solvent .

With the growing importance of composite materials based on plastics , reinforced with natural raw materials , extractions like the one according to Twisselmann are also becoming more and more important in quality assurance in series production . For example, the volume fraction of natural reinforcement fibers in a plastic matrix can be determined by extraction.

The functional principle is very similar to that according to Soxhlet . But in contrast to other extractions such as the one by Franz von Soxhlet , the temperature in the Twisselmann extractor is very high at the level of the sample (close to the boiling point of the solvent). This promises an increased solubility of the phase to be extracted and thus a shortened extraction time. This increased extraction temperature results from the fact that both the condensed, outflowing solvent and the rising, hot solvent vapor , similar to a distillation column , flow through the same extraction flask . This creates a mixture temperature that is higher than that of the condensed solvent. The Knöfler-Böhm extraction works on the same principle.

The Twisselmann extraction attachment is constructed as follows: The actual extraction flask is embedded in a vacuum jacket for better insulation. Small spacers at the bottom of the flask hold the cellulose extraction thimble slightly above the lower drain. In this way, the solvent vapor can flow both through the sleeve and past the sleeve. At the top there is a cut for the reflux condenser attachment, at the bottom one to connect the round bottom flask .

The solvent used depends on the substances to be extracted.

history

The extraction method was published in 1923 by H. Twisselmann.

Web links

Individual evidence

  1. ↑ H.-G. Maier: Food and environmental analysis. Springer-Verlag, 2013, ISBN 978-3-642-72436-7 , p. 39.
  2. ↑ A. Bömer: Handbuch der Lebensmittelchemie , Volume I, second part Chemical and Biological Methods - General methods of investigation. Springer-Verlag, 2013, ISBN 978-3-662-02244-3 , p. 828.
  3. ↑ H. Twisselmann, in: Chem.-Ztg. (1923), Volume 47, p. 506.