The haloalkanes are alkanes containing one or more halogen substituents. They are a subset of the general class of halocarbons, although the distinction is not often made. Haloalkanes are widely used commercially. They are used as flame retardants, fire extinguishants, refrigerants, propellants, solvents, and pharmaceuticals. Subsequent to the widespread use in commerce, many halocarbons have also been shown to be serious pollutants and toxins. For example, the chlorofluorocarbons have been shown to lead to ozone depletion. Methyl bromide is a controversial fumigant. Only haloalkanes that contain chlorine, bromine, and iodine are a threat to the ozone layer, but fluorinated volatile haloalkanes in theory may have activity as greenhouse gases. Methyl iodide, a naturally occurring substance, however, does not have ozone-depleting properties and the United States Environmental Protection Agency has designated the compound a non-ozone layer depleter. For more information, see Halomethane. Haloalkane or alkyl halides are the compounds which have the general formula "RX" where R is an alkyl or substituted alkyl group and X is a halogen.
In organic chemistry, an aryl halide is an aromatic compound in which one or more hydrogen atoms, directly bonded to an aromatic ring are replaced by a halide. The haloarene are different from haloalkanes because they exhibit many differences in methods of preparation and properties. The most important members are the aryl chlorides, but the class of compounds is so broad that there are many derivatives and applications.
Organochlorine chemistry is concerned with the properties of organochlorine compounds, or organochlorides, organic compounds containing at least one covalently bonded atom of chlorine. The chloroalkane class includes common examples. The wide structural variety and divergent chemical properties of organochlorides lead to a broad range of names, applications, and properties. Organochlorine compounds have wide use in many applications, though some are of profound environmental concern, with TCDD being one of the most notorious.
4-Hydroxybenzoic acid, also known as p-hydroxybenzoic acid (PHBA), is a monohydroxybenzoic acid, a phenolic derivative of benzoic acid. It is a white crystalline solid that is slightly soluble in water and chloroform but more soluble in polar organic solvents such as alcohols and acetone. 4-Hydroxybenzoic acid is primarily known as the basis for the preparation of its esters, known as parabens, which are used as preservatives in cosmetics and some ophthalmic solutions. It is isomeric with 2-hydroxybenzoic acid, known as salicylic acid, a precursor to aspirin, and with 3-hydroxybenzoic acid.
In enzymology, a 4-methoxybenzoate monooxygenase (O-demethylating) (EC 1.14.99.15) is an enzyme that catalyzes the chemical reaction
In enzymology, a benzoate 4-monooxygenase (EC 1.14.14.92, Formerly EC 1.14.13.12) is an enzyme that catalyzes the chemical reaction
The enzyme 3-chloro-D-alanine dehydrochlorinase (EC 4.5.1.2) catalyzes the reaction
The enzyme L-2-amino-4-chloropent-4-enoate dehydrochlorinase (EC 4.5.1.4) catalyzes the reaction
In enzymology, a 4-chlorobenzoyl-CoA dehalogenase (EC 3.8.1.7) is an enzyme that catalyzes the chemical reaction
In enzymology, an alkylhalidase (EC 3.8.1.1) is an enzyme that catalyzes the chemical reaction
In enzymology, a haloacetate dehalogenase (EC 3.8.1.3) is an enzyme that catalyzes the chemical reaction
In enzymology, a haloalkane dehalogenase (EC 3.8.1.5) is an enzyme that catalyzes the chemical reaction
In enzymology, a (R)-2-haloacid dehalogenase(EC 3.8.1.9), DL-2-haloacid halidohydrolase (inversion of configuration), DL-DEXi, (R,S)-2-haloacid dehalogenase (configuration-inverting)) is an enzyme that catalyzes the chemical reaction
In enzymology, a (S)-2-haloacid dehalogenase (EC 3.8.1.2) is an enzyme that catalyzes the chemical reaction
In enzymology, a 4-chlorobenzoate—CoA ligase is an enzyme that catalyzes the chemical reaction
The enzyme 4-hydroxybenzoyl-CoA thioesterase (EC 3.1.2.23) catalyzes the reaction
2-haloacid dehalogenase (configuration-inverting) (EC 3.8.1.10, 2-haloalkanoic acid dehalogenase, 2-haloalkanoid acid halidohydrolase, DL-2-haloacid dehalogenase, DL-2-haloacid dehalogenase (inversion of configuration), DL-2-haloacid halidohydrolase (inversion of configuration), DL-DEXi, (R,S)-2-haloacid dehalogenase (configuration-inverting)) is an enzyme with systematic name (S)-2-haloacid dehalogenase (configuration-inverting). This enzyme catalyses the following chemical reaction
2-haloacid dehalogenase (configuration-retaining) (EC 3.8.1.11, 2-haloalkanoic acid dehalogenase, 2-haloalkanoid acid halidohydrolase, DL-2-haloacid dehalogenase, DL-DEXr) is an enzyme with systematic name (S)-2-haloacid dehalogenase (configuration-retaining). This enzyme catalyses the following chemical reaction
Adsorbable Organic Halides (AOX) is a measure of the organic halogen load at a sampling site such as soil from a land fill, water, or sewage waste. The procedure measures chlorine, bromine, and iodine as equivalent halogens, but does not measure fluorine levels in the sample.
Transhalogenation is a substitution reaction in which the halide of a halide compound is exchanged for another halide.
