Wurtz

Elimination of halogen by sodium (Wurtz s reaction) gives a higher hydrocarbon. 

This reaction is precisely parallel to the Wurtz Reaction in the aliphatic series, by which, for instance, n-butane can be obtained by the action of sodium on ethyl bromide. 

All hydrocarbons prepared by th -. Wurtz reaction contain small quantities of unsaturated hydrocarbons. These may be removed by shaking repeatedly with 10 pier cent, of the volume of concentrated sulphuric acid until the acid is no longer coloured (or is at most extremely pale yellow) each shaking should be of about 5 minutes duration. The hydrocarbon is washed with water, 10 pier cent sodium carbonate solution, water (twice), and dried with anhydrous magnesium or calcium sulphate. It is then distilled from sodium two distillations are usually necessary... 

Aliphatic hydrocarbons can be prepared by the reduction of the readily accessible ketones with amalgamated zinc and concentrated hydrochloric acid (Clemmensen method of reduction). This procedure is particularly valuable for the prep>aration of hydrocarbons wdth an odd number of carbon atoms where the Wurtz reaction cannot be applied with the higher hydrocarbons some secondary alcohol is produced, which must be removed by repeated distillation from sodium. 

Wurtz - Fittig reaction. The interaction of an aryl halide, alkyl hahde and sodium gives a reasonable yield of an alkyl aryl hydrocarbon, for example ... 

Two mechanisms have been proposed for the Wurtz reaction (compare Section III,7) and for the Wurtz-Fittig reaction. According to one, sodium reacts with the alkyl halide to produce a sodium halide and a free radical, which subsequently undergoes coupling, disproportionation, etc. ... 

Williamson synthesis Wohl-Ziegler reaction Wolff rearrangement Wolff Kishner reduction Wurtz reaction Wurtz-Fittig reaction... 

As stated above, intermolecular coupling reactions between carbon atoms are of limited use. In the classical Wurtz reaction two identical primary alkyl iodide molecules are reduced by sodium. /i-Hectane for example, has been made by this method in 60%... 

Shortly thereafter but independently of Kekule Archibald S Couper a Scot working m the laboratory of Charles Adolphe Wurtz at the Ecole de Medicine m Pans and Alexan der Butlerov a Russian chemist at the University of Kazan proposed similar theories... 

Wurster process Wurster salts Wurtz-Fittigcoupling Wurtz-Fittig reaction Wurtzite... 

WurtZ-Type Coupling of Dihalosilanes. Several approaches have been developed for the synthesis of polysdanes. However, the most commonly utilized method is based on the Wurtz-type alkah metal coupling of dichlorosilanes. Both homo- and copolymers can be prepared this way (eq. 10). 

Sodium and magnesium do not react with tetrachlorosilane at room temperature, but do so at elevated temperatures and ia the presence of polar aprotic solvents at moderately elevated temperatures. The Wurtz-Fittig coupling of organosilanes to form disilanes (168) and polysdanes (169) is usually accomphshed usiag molten sodium ia toluene or xylene. 

The Wurtz reaction, which reties on in situ formation of an active organosodium species, is also usefiil for preparing tetraorganotin compounds and is practiced commercially. Yields are usually only fair and a variety of by-products, including ditins, also form ... 

A variant of the Wurtz reaction is the preparation of tetrabutyltin from activated magnesium chips, butyl chloride, and stannic chloride in a hydrocarbon mixture. Only a small amount of tetrahydrofuran is required for the reaction to proceed in high yield (86). 

Hypochlorination. Both ethylene chloiohydiin and propylene chloiohydiin were prepared by Wurtz (12) as a result of the reactions of HCl [7647-01-0] with the corresponding glycol under pressure. Shordy afterward, Carius (13) synthesized ethylene chlorohydria by reaction of hypochlorous acid with ethylene [74-85-1]. The first detailed iavestigation of the formation of ethylene chlorohydria by the reaction of ethylene with hypochlorous acid [7790-92-3] was performed by Gomberg (14). 

Dehydrochlorination to Epoxides. The most useful chemical reaction of chlorohydrins is dehydrochlotination to form epoxides (oxkanes). This reaction was first described by Wurtz in 1859 (12) in which ethylene chlorohydria and propylene chlorohydria were treated with aqueous potassium hydroxide [1310-58-3] to form ethylene oxide and propylene oxide, respectively. For many years both of these epoxides were produced industrially by the dehydrochlotination reaction. In the past 40 years, the ethylene oxide process based on chlorohydria has been replaced by the dkect oxidation of ethylene over silver catalysts. However, such epoxides as propylene oxide (qv) and epichl orohydrin are stiU manufactured by processes that involve chlorohydria intermediates. 

With Water. Wurtz was the first to obtain ethylene glycol by heating ethylene oxide and water in a sealed tube (1). Later, it was noted that by-products, namely diethjlene and triethylene glycol, were also formed in this reaction (50). This was the first synthesis of polymeric compounds of well-defined stmcture. Hydration is slow at ambient temperatures and neutral conditions, but is much faster with either acid or base catalysis (Table 8). The type of anion in the catalyzing acid is relatively unimportant (58) (see Glycols). 

Another condensation method was investigated by Carothers and co-workers and reported in 1930. They reacted decamethylene dibromide with sodium in a Wurtz-type reaction but found it difficult to obtain polymers with molecular weights above 1300. 

Poly-p-phenylene has been prepared in the laboratory by a variety of methods, including the condensation of p-dichlorobenzene using the Wurtz-Fittig reaction. Although the polymer has a good heat resistance, with decomposition... 

The first isocyanates were produced by Wurtz in 1849 by reacting organic sulphates with cyanic acid salts. 

This reaction, based on the Wurtz reaction, tends to go to completion and the yield of technically useful chlorosilane is low. 

All three routes are used on an industrial scale and the Grignard route (or the equivalent organo-Li reagent) is convenient for laboratory scale. Rather less used is the modified Wurtz-type reac-8 Na... 

In addition to its uses in photography and medicine, iodine and its compounds have been much exploited in volumetric analysis (iodometry and iodimetry, p. 864). Organoiodine compounds have also played a notable part in the development of synthetic organic chemistry, being the first compounds used in A. W. von Hofmann s alkylation of amines (1850), A. W. Williamson s synthesis of ethers (1851), A. Wurtz s coupling reactions (1855) and V. Grignard s reagents (1900). 

Dehydration to 2-vinylthiophene is better achieved from 2-(2-thienyl) ethanol with powdered potassium hydroxide in the presence of copper than from 1-(2-thienyl) ethanol. a-Chloro-2-thienylpro-pane undergoes a Wurtz reaction with active iron to give 3,4-di-(2-thienyl) hexane in low yield, which has also been obtained through coupling with n-butyllithium. ... 

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