Chlorophenyl silicone

A halogenated aryl group also may be used in conjunction with an alkyl group, as in methyl chlorophenyl silicone. If the aryl group contains chlorine in sufficient proportion, it can suppress the flammability of the alkyl group so that the entire composition is flameproof. 

In the case of the experiments performed by Hohman and co-workers [149], the fluoride anion would readily displace the silicon-leaving group. The peroxide anion could then further react via an intramolecular nucleophilic attack, resulting in cyclization to form the reactive intermediate responsible for the chemiluminescence that was observed. A recent kinetic study by Stevani and Baader [150] of the reaction of 4-chlorophenyl-O,O-hydrogen monoperoxyoxalate with various oxygen and nitrogen bases suggested that the intermediate formed must be 1,2-dioxetandione. 

Chlorophenols, manufacture of, 23 654 Chlorophenoxy acid herbicides, 73 304 (E) -(RS) -1 -(4-Chlorophenyl) -4,4-dimethyl-2-(lH- l,2,4-triazol-l-yl)-pent-l-en-3-ol, 73 47—48. See also 4-Chlorophenyl-4,4- dimethyltriazol pentenol 4-Chlorophenyl-4,4-dimethyltriazol pentenol, 73 40t, 47 48 Chlorophosphazenes, 19 55, 56 in silicone polymerization, 22 556... 

Phenyl(chloromethyl)dichlorosilanes and methyl(chlorophenyl)-dichlorosilanes are colourless, transparent, motile liquids, which fume in air. Like all organochlorosilanes, they are easily hydrolysed with water and humidity in air and dissolve well in organic solvents. Phenyl(chloromethyl)- and methyl(chlorophenyl)dichlorosilanes are raw stock for preparing various silicone liquids, elastomers, and polymers for varnishes. 

Figure 17-2. Viscosity-temperature behavior of various types of synthetic lubricants. 1 White oil, VI 101. 2 4 -Undecy1-m-terphenyl. 3 Fluoroalkane. 4 -Di (chlorophenyl )pentane. 5 Polyphenyl ether. 6 Polyoxyalkylene glycol. 7 Di(2-ethylhexyl) sebacate. 8 Dimethyl silicone.

Figure 17-2 shows the influence of temperature on the viscosity of representative examples of synthetic fluids of various chemical types. Direct comparisons can be made when individual fluids have the same viscosity at a given temperature e.g. white oil and polyoxyalkylene glycol at 301 K (83 F). The viscosity of the glycol fluid at 372 K (210 F) is 6 Saybolt seconds higher than that of white oil, which is a significant difference that immediately shows the better viscosity behavior of the synthetic fluid. In similar fashion, u,u -di(chlorophenyl)pentane, di(2-ethylhexyl) sebacate and a dimethyl silicone all have a viscosity of 120 Saybolt seconds at 340 K (153 F) but at 372 K there is a spread of 15.7 Saybolt seconds in the viscosity behavior of these fluids. 

Silicone oils are good hydrodynamic lubricants but have generally poor frictional lubricating properties (352—354). The latter can be improved by incorporating chlorophenyl groups into the polymer side chains (355). For steel on steel, the coefficient of friction is about 0.3—0.5. The load-bearing capacity of PDMS (Almen-Wieland machine) is only 50—150 kg, compared with 1000 kg for polychlorophenylmethylsiloxane and up to 2000 kg for mineral oil. 

Internet search are Legionnaires disease, Agent Orange, breast cancer and silicone implants, thalidomide, and Bendectin. The National Cancer Institute has many fact sheets on a wide range of topics related to cancer at http //www.cancer.gov/cancertopics/factsheet/Risk. Two other examples are a false positive in early studies of breast cancer associated with serum level of DDE [l,l-dichloro-2,2-bis(p-chlorophenyl)ethylene] and a false positive between acrylonitrile exposure and lung cancer in occupational settings. 

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