Extraction is a separation of a substance from the mixture with the division of a solute between two solvents that can not be mixed to take these solutes from one solvent to another solvent. Often a mixture of solid and liquid materials (natural misalnyabahan) can not or is very difficult to be separated by mechanical or thermal separation methods that have been discussed. For example, because the components are mixed with each other very closely, sensitive to heat, different physical properties are too small, or are available in concentrations that are too low.
In this kind of thing. It's often the extraction is the only process that can be used or that may be most economical. For example the manufacture of esters (essence) to the smells in the manufacture of syrup or perfumes, making caffeine from tea leaves, coffee beans or cocoa beans and that can be seen daily is dissolving the components of coffee with hot water from coffee beans been burnt or ground.
Preparation of Material to be Extracted and Solvent
Selectivity
Pelarat may only dissolve the desired extract, not the other components of materials extraction. In practice, especially in the extraction of natural materials, often also other materials (eg fats, resins) released participate together with the desired extract. In the event that contaminated extract solution obtained should be cleaned, ie for example extracted again by using a second solvent.
Solubility Solvent as far as possible have a great ability to dissolve extracts (needs less solvent).
Ability are not mutually mixed In liquid-liquid extraction, solvent may not (or only a limited basis) soluble in the extraction of materials.
The density
Especially in the liquid-liquid extraction, as far as possible there is a large difference in density between the solvent and extraction. This is so both phases can be easily separated again after mixing (separation by gravity). When the density difference is small, the separation often have to do with
using centrifugal force (eg in centrifugal extractor).
Reactivity
In general, the solvent should not cause chemical changes in materials komponenkornponen ekstarksi. Conversely, in certain cases it is necessary chemical reactions (eg formation of salt) to obtain high selectivity. Extraction is often accompanied by chemical reaction. In this case the material to be separated absolutely must be in solution form.
Boiling Point
Because solvent extracts and usually must be separated by evaporation, distillation or rectification, then the point didit both materials should not be too close, and they do not form ascotrop.Ditinjau economically, would be advantageous if the boiling point solvent extraction process is not too high (as well as the low heat of vaporization).
Selectivity
Pelarat may only dissolve the desired extract, not the other components of materials extraction. In practice, especially in the extraction of natural materials, often also other materials (eg fats, resins) released participate together with the desired extract. In the event that contaminated extract solution obtained should be cleaned, ie for example extracted again by using a second solvent.
Solubility Solvent as far as possible have a great ability to dissolve extracts (needs less solvent).
Ability are not mutually mixed In liquid-liquid extraction, solvent may not (or only a limited basis) soluble in the extraction of materials.
The density
Especially in the liquid-liquid extraction, as far as possible there is a large difference in density between the solvent and extraction. This is so both phases can be easily separated again after mixing (separation by gravity). When the density difference is small, the separation often have to do with
using centrifugal force (eg in centrifugal extractor).
Reactivity
In general, the solvent should not cause chemical changes in materials komponenkornponen ekstarksi. Conversely, in certain cases it is necessary chemical reactions (eg formation of salt) to obtain high selectivity. Extraction is often accompanied by chemical reaction. In this case the material to be separated absolutely must be in solution form.
Boiling Point
Because solvent extracts and usually must be separated by evaporation, distillation or rectification, then the point didit both materials should not be too close, and they do not form ascotrop.Ditinjau economically, would be advantageous if the boiling point solvent extraction process is not too high (as well as the low heat of vaporization).
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