1.3- Dichloro siloxane

Bis-pyrimidine derivatives were prepared by the reaction of the hydroxyethyl derivatives of pyrimidine with various bifunctional compounds such as dichloro-siloxane derivatives (Figure 3) (20). 

Molecular weights of polydimethyl siloxanes can reach 700,000 or higher. Within the range of molecular weights between 4,000 and 25,000, the materials are fluids of various viscosities. Most common commercial liquid polydimethyl siloxanes are prepared from dimethyl dichloro siloxane. Many elastomers are also based on dimethylsiloxane. Special polymers are prepared with other substituents. 

Poly( w-carborane-siloxane) rubbers are most commonly prepared by a ferric chloride-catalyzed bulk condensation copolymerization of dichloro- and dimethoxy-terminated monomers with alkylchloro- or arylchloro-siloxanes.16... 

The reaction of l,3-dichloro(tetramethyl)siloxane 12 with f-butyl hydroperoxide in the presence of pyridine in ether gave l-f-butylperoxy-3-chlorotetramethyldisiloxane 13 in 60% yield (equation 19). 

Only the reduction of oxygen in the presence of dichloro- or dimethoxysilanes results in their transformation into the mixture of cyclic and linear siloxanes. These siloxane products arise from autocyclization and oligomerization of electrogenerated transient silanones and their insertion into Si-O bonds of primarily formed siloxanes. 

Volatile Organic Compound (VOC), means any compound of carbon, excluding carbon monoxide, carbon dioxide, carbonic acid, metallic carbides or carbonates, and ammonium carbonate, which participates in atmospheric photochemical reactions. This includes any such organic compound other than the following, which have been determined to have negligible photochemical reactivity Methane ethane methylene chloride (dichloro-methane) 1.1.1-trichloroethane (methyl chloroform) l.l.l-trichloro-2.2.2-trifluorethane (CFC-113), furthermore cyclic, branched or linear completely methylated siloxanes acetone and perfluorocarbon compounds. 

The polycondensation only occurs in the presence of siloxane groups, that is, for example, it does not occur with dichlorosilane. In such a case, the dichloro compounds are first converted to the respective dimethoxy derivatives (from the reaction of the dichloro compounds with methanol) ... 

---