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In enzymology, a haloalkane dehalogenase (EC 3.8.1.5) is an enzyme that catalyzes the chemical reaction 1-haloalkane + H 2 O ⇌ {\displaystyle \rightleftharpoons } a primary alcohol + halide Thus, the two substrates of this enzyme are 1-haloalkane and H 2 O , whereas its two products are primary alcohol and halide .
Darzens halogenation is the chemical synthesis of alkyl halides from alcohols via the treatment upon reflux of a large excess of thionyl chloride or thionyl bromide (SOX 2) in the presence of a small amount of a nitrogen base, such as a tertiary amine or pyridine or its corresponding hydrochloride or hydrobromide salt.
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 ...
In general, the reaction of a haloalkane with potassium hydroxide can compete with an S N 2 nucleophilic substitution reaction by OH − a strong, unhindered nucleophile. Alcohols are however generally minor products. Dehydrohalogenations often employ strong bases such as potassium tert-butoxide (K + [CH 3] 3 CO −).
Arrow-pushing mechanism for the Darzens reaction. If the starting halide is an α-halo amide, the product is an α,β-epoxy amide. [8] If an α-halo ketone is used, the product is an α,β-epoxy ketone. [2] Any sufficiently strong base can be used for the initial deprotonation.
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.
A reaction mechanism was first introduced by Christopher Ingold et al. in 1940. [3] This reaction does not depend much on the strength of the nucleophile, unlike the S N 2 mechanism. This type of mechanism involves two steps. The first step is the ionization of alkyl halide in the presence of aqueous acetone or ethyl alcohol.
The Williamson ether synthesis is an organic reaction, forming an ether from an organohalide and a deprotonated alcohol . This reaction was developed by Alexander Williamson in 1850. [ 2 ] Typically it involves the reaction of an alkoxide ion with a primary alkyl halide via an S N 2 reaction .