|
Home >> Chemistry Dictionary >>Chlorine Water Chromatography
|
|
Chlorine water.
Refers to a solution of chlorine in water, the dissolution gets accompanied by the reaction:
Cl2+H2O HCl + HClO
Chloro acids.
Complex choloranions are formed by most elements of the periodic table by solution of oxides or chlorides in concentrated hydrochloric acid. Potassium chloride is added to a solution of acid Chloro acid, the free acids are generally unstable.
Chlorobenzene.
A colourless highly inflammable liquid, C6H5Cl; r.d. 1.106; m.p. —45.43°C; b.p. 131.85°C. It is prepared by the direct chlorination of benzene using halogen carries (see Friedel-Crafts reaction), or manufactured by the Resching process. It is used mainly as an industrial solvent.
|
Chloro ethane (Ethyl chloride, C2H5Cl).
A gas obtained by adding hydrochloric acid to ethylene in the presence of AlCl3. It is used in the preparation of tetra-ethyl lead, sulphonal and as a refrigerating agent.
Chloro Ethanoic Acid (Chloro Acetic Acid, CH2ClCOOH).
A colourless crystalline solid prepared by substituting one of the hydrogen atom of methyl group of ethanoic acid chlorine, using red posphorus. It is a stronger acid than acetic acid because of the electron with drawing effect of the chlorine atom.
Chloro Ethene (Vinyl Chloride H2C=CHCl).
A colourless gas obtained by passing acetylene gas into dilute hydrochloric acid at 340 K in the presence of Hg2+ ions (catalyst). It is used in the manufacture of plastics.
|
Chloroform, trichloromethane, CHCl3
Colourless liquid with a sweet, pleasant odour; b.p. 60-61°C. Very slightly soluble in water; the solution has a sweet taste. Manufactured by the chlorination of methane. Oxidized by air and sunlight to phosgene; the addition of a small amount of alcohol prevents this. It is an excellent solvent for oils, fats, waxes, rubber and many other organic substances. Characteristically form phenyl isocyanide when it is warmed aniline and potassium hydroxide. Bromoform, iodoform and chloral also give this carbylamine reaction.
Chloroform is a potent volatile anaesthetic, but is little due to its potential hepatotoxicity. It is used principally for the manufacture of chlorofluorohydrocarbon refrigerants (‘Arctons’ and Ferons’) and certain polymers.
|
|
Choromethane (methyl chloride)
A colourless flammable gas, CH3Cl; r.d.0.916; m.p. —97°C; b.p. —24°C It is a haloalkane, made by direct chlorination of methane and used as a local anaesthetic and refrigerant.
Chlorophenols
Relatively acidic materials produced by direct chlorination of the aromatic nucles of phenols. Used widely in phenolresins (with methanol) the compounds are often effective antiseptics, disinfectants, germicides, insecticides, herbicides, wood preservatives, Also used in dyestuffs.
|
|
|
Chloropicrin, nitrotrichloromethane,
CCl3NO2. A colourless lachrymatory, toxic liquid; b.p. 112°C. Manufactures by treating sodium picrate with chlorine, or calcium picrate with bleaching powder. Poison gas, it is used as an insecticide, parasiticide and for disinfecting cereals.
Chloroplatinic acid
A reddish crystalline compound H2 PtCl6, obtained by dissolving platinum in aqua regia.
Chlorous acid.
HClO2. Unknown in the free state but chlorates (III), chlorites, well known and used as oxidizing agents and as bleaches.
|
Cholesterol oxidase.
An enzyme from various soil micro-organism that oxidizes cholesterol to cholest-4-en-3- one using molecular oxygen, with the concomitant production of hydrogen peroxide. Many methods of assaying cholesterol using the enzyme are based on measuring H2O2production.
Chromate.
A salt containing the ion CrO42-
Chromatogram.
A record obtained by chromatography. The term is applied to the developed records of paper chromatography and thin-layer chromatography and also to the graphical record produced in gas chromatography.
Chrotomatography.
A technique for analysing or separating mixtures of gases, liquids, or dissolved substances. The original techniques (invented by the Russian botanist Mikhail Tsvet in 1906) is a good example of column chromatography. A vertical glass tube is packed with an absorbing material, such as alumina. The sample is poured into the column and continuously washed through with a solvent (a process known as elution). Different components of the sample are absorbed to different extents and move down the column at different rates. In Tsvet’s original application, plant pigments were used and these separated into coloured bands in passing down the column (hence the name chromatography). The usual method is to collect the liquid (the eluate) as it passes out from the column in fractions.
The chromatogram can finally be used as the series bands of zones of components or the components can be eluted successively and then detected by various means (e.g. thermal conductivity, flame ionization, electron capture detectors, or the bands can be examined chemically). If the detection is non-destructive, preparative scale chromatography can separate measurable and useful quantities of components. The final detection stage can be coupled to a mass spectrometer (GCMS) and to a computer fro final identification.
Among the various chromatographic methods are absorption column chromatography (use of a liquid phase in a solid column of odsorbent), partition column chromatography (distribution between two liquids in a column) thinlayer chromatography (partition on an open thin sheet), paper chromatography (use of a paper sheet as stationary phase), high pressure chromatography, hplc, (partition column chromatography under high pressure), ion exchange chromatography (ion exchange), gas chromatography (distribution of a gaseous solute between a gas and a liquid or solid phase), zone electrophoresis (sheet chromatography in the presence of an electric field).
|
|
