finkelstein reaction- this is the exclusively method for preparation of alkyl iodide. The Finkelstein reaction relies on the precipitation of an insoluble salt to drive the reaction, generally sodium chloride or sodium bromide. It is an organic reaction that uses an alkyl halide exchange into another alkyl halide through a reaction wherein the metal halide salt is used. In Finkelstein reaction,dry acetone is used as a solvent.Acetone is a polar aprotic solvent . It is named after the Hans Finkelstein, a German chemist.
Finkelstein reaction is used to prepare alkyl iodides starting from alkyl chlorides and alkyl bromides. when acetone is pure which having water, its used in Finkelstein's reaction to facilitates the forward reaction according to Le Chatelier's Principle In This Reaction, The Alkyl Chloride Or Bromide Is Added To A Solution Of Nal In Acetone. In acetone medium , NaI is soluble but NaCl is insoluble because the negative charge on oxygen atom of acetone is repelled with the negative charge of Cl – atom . Finkelstein reaction is a halogen exchange reaction between haloalkane and a salt of a different halogenide. Alkyl Iodides are often prepared by the reaction of alkyl chlorides/bromides with NaI in dry Acetone, This reaction is known as Finkelstein's Reaction. Acetone is a widely used organic solvent thus in anhydrous condition i.e. Thus anhydrous conditions are required. It is used to synthesize one alkyl halide from another. In his original work, Finkelstein notes that precipitation occurs and implies that this makes the reaction cleaner, but makes no clear statement about the reversibility. It is generally used in those reactions where sodium is required like in Finkelstein reaction. The driving force in this reaction is precipitation of $\ce{KCl}$. Hence, dry acetone is used. Finkelstein's Reaction is an imporatant reaction because preperation of RI is difficult than preparing RCl or RBr The classic Finkelstein reaction entails the conversion of an alkyl chloride or an alkyl bromide to an alkyl iodide by treatment with a solution of sodium iodide in anhydrouss acetone ().You can find here why this reaction works in this manner.. Halogen exchange is very old , but the innovation of Finkelstein was to use a solution of NaI in acetone, which gave cleaner reactions (as for example in alcohols). Finkelstien reaction involves displacement of one hallide present on alkyl present to another hallide.We use Acetone as a reagent in this reaction because in anhydrous condition i.e. In Swarts reaction we use metallic fluoride along with alkyl halide. In Finkelstein reaction, alkyl iodides are prepared by the reaction of alkyl chlorides/bromides with NaI in dry acetone.. In Swarts reaction ,dry acetone is used as a solvent. * The Finkelstein reaction involves the exchange of one halogen for another, especially, in primary alkyl halides. This means that the reaction is shifted to the right because the formation of the alkyl iodide is accompanied by the precipitation of NaBr/Cl. Now I have found hard data for the Finkelstein equilibrium in solution and have to negate my earlier guess: According to Hughes/Ingold and coworkers, the reaction LiI + RBr = LiBr + RI is indeed reversible and not favorable for the alkyl iodides: K is 0.5 for MeBr, 0.12 for EtBr and 0.04 for iPrBr, which means that the homogeneous halogen exchange reaction is indeed thermodynamically uphill.