Wurtz column

In the Grignard reaction, which is very important in the manufacture of a variety of fine chemicals, the continuous reactor for production of the reagent consists of a column of magnesium particles through which a solution of the organohalogen compound in an ether-class solvent is passed. The continuous mode of operation reduces side reactions, particularly Wurtz-type coupling, which make many reactions impractical. 

Assemble an apparatus for the preparation of dry ammonia (Fig. 62a). To do this, put solid sodium hydroxide wear eye protection and handle the alkali with a porcelain spoon ) into two-neck bottle 1 or a Wurtz flask. Pour a 25 % ammonia solution into dropping funnel 2. Put soda lime or a granulated alkali into drying columns 3. Pour glycerin or vaseline oil (a bubble counter) into wash bottle 4. 

Chlorpromazine undergoes a Wurtz condensation on passing through a column filled with pyrophoric lead, giving bispromazine (129) in 90% yield. ... 

Smooth vertical tvbes, with diameters of 20—50 mm, are now rarely used for. separations, except as spray traps in simple distillations. Their HETP will not be lower than about 10 cm unless the load is small, say less than 30 ml/h. Attempts have therefore been made to improve their efficiency by increasing their surface area. The Wurtz (r/. Fig. 15) and Young columns, consisting, respectively, of series of simple and pear-shaped bulbs, produce a better separation, but have a laiger holdup. Data for unfilled columns are given in Table 55. 

Wurtz s discovery of isobutyl alcohol was important when so few alcohols were known he used a rectifying column consisting of a tube with two bulbs. He prepared many derivatives of isobutyl alcohol, introducing a method of preparing ethers by the action of dry silver oxide on alkyl iodides, which he later extended. ... 

A regiospecific transposition of the allyl fragment involving exclusive y-reaction is observed e.g. 27 -> 28) in both studies. A related reaction between (presumably) allylic zinc derivatives and aldehydes or ketones occurs when a mixture of an allylic bromide and the carbonyl compound is passed along a column of zinc granules heated at the reflux temperature of THF. Hydrolysis of the resultant zinc alkoxide provides another route to homoallylic alcohols (Scheme 12), with no problem from Wurtz coupling of the bromide. The column may be used repeatedly without contamination, providing the zinc is replenished as it is used up. ... 

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