CHEMISTRY GLOSSARY

extraction    →   ekstrakcija

Extraction is the separation of a component from its mixture by selective solubility. When a solution of one substance in one solvent is brought in with another solvent dissolved substance will distribute between the two solutants because of different solubility. Extraction is an efficient and fast method used for separating and concentrating matters. Extraction is best done several times in a succession, with smaller amount of solvent in it the matter is better dissolved. For example, caffeine can be separated from coffee beans by washing the beans with supercritical fluid carbon dioxide; the caffeine dissolves in the carbon dioxide, but flavour compounds do not. Vanillin can be extracted from vanilla beans by shaking the beans with an organic solvent, like ethanol.

supercritical fluid extraction    →   superkritična fluidna ekstrakcija

Supercritical fluid extractions (SFE) have solvating powers similar to liquid organic solvents, but with higher diffusivities, lower viscosity, and lower surface tension. The main advantages of using supercritical fluids for extractions is that they are inexpensive, contaminant free, and less costly to dispose safely than organic solvents. For non-destructive isolation choose SFE, which is simply the best technology for sensitive raw materials. For these reasons supercritical carbon dioxide (scCO₂) is the reagent used to extract caffeine from coffee and tea. Its gaslike behavior allows it to penetrate deep into the green coffee beans, and it dissolves from 97 % to 99 % of the caffeine present.

biocapacity    →   biokapacitet

Biocapacity (or biological capacity) is the capacity of ecosystems to produce useful biological materials and to absorb carbon dioxide generated by humans, using current management schemes and extraction technologies. Useful biological materials are defined as those used by the human economy, hence what is considered useful can change from year to year. The biocapacity of an area is calculated by multiplying the actual physical area by the yield factor and the appropriate equivalence factor.

Yield factor is a factor that accounts for differences between countries in productivity of a given land type. Each country and each year has yield factors for cropland, grazing land, forest, and fisheries.

Equivalence factor is a productivity based scaling factor that converts a specific land type into a universal unit of biologically productive area, a global hectare (gha).

concentration of ore    →   koncentriranje ruda

Concentration of ores is important industrial processes and is the first steps to the extraction of the metals. Normally, the ore is concentrated by separating it from the clay body in which it occurs either by gravity, sedimentation, or by a floatation process, before the extraction of the metal from the ore is started.

metallurgy    →   metalurgija

Metallurgy is a science which studies metals and their extraction from ore.

Nernst’s division law    →   Nernstov zakon razdjeljenja

Nernst’s division law states that a substance is divided between two solvents in a way that proportion of concentrations of that substance is at certain temperatures constant, under the condition that both solvents are in the same molecular state. Division coefficient is a proportion of substance concentration in solvents A i B at a defined temperature.

Appearance of division is used for substance extraction.

percolation    →   perkolacija

Percolation is a procedure of extraction of a material in special pipes through which a solvent is gradually released.

purification    →   pročišćavanje

Purification is the physical or chemical process of removing contaminants from a compound. The physical processes may include sublimation, distillation, filtration, crystallisation, or extraction. The chemical processes may involve formation of a derivative, purification of the derivative and recovery of the original material in a pure form of the derivative.

SFE    →   SFE

SFE is abbreviation for supercritical fluid extraction.

Soxhlet extractor    →   Soxhletov ekstraktor

Soxhlet extractor is a laboratory apparatus designed to extract substances with a low solubility in the extracting solvent. The method described by the German chemist Franz von Soxhlet (1848-1926) in 1879 is the most commonly used example of a semi-continuous method applied to extraction of lipids from foods. In the Soxhlet extractor, the sample soaks in hot solvent that is periodically siphoned off, distilled and returned to the sample. During each cycle, a portion of the non-volatile compound dissolves in the solvent. After many cycles the desired compound is concentrated in the distillation flask. The solvent in the flask is then evaporated and the mass of the remaining lipid is measured.