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The Wijs solution, iodine monochloride dissolved in acetic acid, is used to determine the iodine value of a substance. It can also be used to prepare iodates, by reaction with a chlorate. Chlorine is released as a byproduct. Iodine monochloride is a Lewis acid that forms 1:1 adducts with Lewis bases such as dimethylacetamide and benzene.
Melzer's reagent is an aqueous solution of chloral hydrate, potassium iodide, and iodine.Depending on the formulation, it consists of approximately 2.50-3.75% potassium iodide and 0.75–1.25% iodine, with the remainder of the solution being 50% water and 50% chloral hydrate.
Bis(pyridine)iodonium(I) tetrafluoroborate or Barluenga's reagent, named after José Barluenga, [1] is a mild iodinating reagent. Commercially available, it may be prepared by reacting iodine with pyridine in the presence of silver tetrafluoroborate supported on silica gel .
The reaction can also be carried out under mildly acidic conditions by way of the same intermediate using a hypervalent iodine compound in aqueous solution. [1] An example published in Organic Syntheses is the conversion of cyclobutanecarboxamide , easily synthesized from cyclobutylcarboxylic acid , to cyclobutylamine . [ 2 ]
Iodine trichloride, which exists in the solid state as the planar dimer I 2 Cl 6, is a bright yellow solid, synthesised by reacting iodine with liquid chlorine at −80 °C; caution is necessary during purification because it easily dissociates to iodine monochloride and chlorine and hence can act as a strong chlorinating agent.
In the latter case, an overlay of blue and red can be observed in Lugol's solution without KOH pretreatment: a color change from blue to dirty reddish-brown occurs when the iodine reagent slowly diffuses into the water preparation, because the euamyloid reaction appears at lower iodine concentrations than the hemiamyloid reaction.
The mechanism of carbonyl oxidation by iodine(III) reagents varies as a function of substrate structure and reaction conditions, but some generalizations are possible. Under basic conditions, the active iodinating species are iodine(III) compounds in which any relatively acidic ligands on iodine (such as acetate) have been replaced by alkoxide. [1]
Grignard reagents or Grignard compounds are chemical compounds with the general formula R−Mg−X, where X is a halogen and R is an organic group, normally an alkyl or aryl. Two typical examples are methylmagnesium chloride Cl−Mg−CH 3 and phenylmagnesium bromide (C 6 H 5 )−Mg−Br .