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In chemistry, the haloform reaction (also referred to as the Lieben haloform reaction) is a chemical reaction in which a haloform (CHX 3, where X is a halogen) is produced by the exhaustive halogenation of an acetyl group (R−C(=O)CH 3, where R can be either a hydrogen atom, an alkyl or an aryl group), in the presence of a base.
Trihalomethanes with all the same halogen atoms are called haloforms. Many trihalomethanes find uses in industry as solvents or refrigerants . Some THMs are also environmental pollutants , and a few are considered carcinogenic .
Bromoform was discovered in 1832 by Löwig who distilled a mixture of bromal and potassium hydroxide, as analogous to preparation of chloroform from chloral. [5]Bromoform can be prepared by the haloform reaction using acetone and sodium hypobromite, by the electrolysis of potassium bromide in ethanol, or by treating chloroform with aluminium bromide.
It is a hydrofluorocarbon as well as being a part of the haloforms, a class of compounds with the formula CHX 3 (X = halogen) with C 3v symmetry. Fluoroform is used in diverse applications in organic synthesis. It is not an ozone depleter but is a greenhouse gas. [2]
In acidic solution, usually only one alpha hydrogen is replaced by a halogen, as each successive halogenation is slower than the first. The halogen decreases the basicity of the carbonyl oxygen, thus making protonation less favorable. However, in basic solutions, successive halogenation is more rapid due to inductive electron withdrawal by the ...
Structure of an η 2-formaldehyde complex. Transition metal complexes of aldehydes and ketones describes coordination complexes with aldehyde (RCHO) and ketone (R 2 CO) ligands. Because aldehydes and ketones are common, the area is of fundamental interest. Some reactions that are useful in organic chemistry involve such complexes.
Hume-Rothery rules, named after William Hume-Rothery, are a set of basic rules that describe the conditions under which an element could dissolve in a metal, forming a solid solution. There are two sets of rules; one refers to substitutional solid solutions, and the other refers to interstitial solid solutions.
The derivative CH 3 B=C(SiMe 3) 2 is fairly stable, but prone to cyclodimerisation. [19] Some boron-substituted heterocycles are aromatic, but very few such arenes are stable. In borabenzene, boron replaces one CH center in benzene. Borabenzene and derivatives invariably appear as adducts, e.g., C 5 H 5 B-pyridine.