Halogens, elemental industrial preparation

A review of the means whereby the elements of the halogen family may be prepared either in the laboratory or on an industrial scale provides further insight into the interrelationships of these elements. 

The silicones are straight or branched linear polymers in which the difunctional —O—SifRj)—O— or trifunctional —O—Si(R) (O)—O— siloxane elements form a system of extended chains. These chains can be prepared, if necessary, with molecular weights on the order of 1 million. Both ends of the chain are capped with a monofunctional residue RjSiO—, or with reactive groups (H, OH, OR, halogen, etc.) The basic unit of all industrial silicones is dimethylpolysiloxane. The starting material for this is dichlorodimethylsilane, which is hydrolysed to form dimethylsilanediol and dimethylcyclosiloxane (Eq. 4.1, 4.2) ... 

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