Organosilicones

Figure 4.50 from Molecular Parameters for Organosilicon Compounds Calculated from Ab Initio Computations, Grigoras S and T H Lame, Journal of Computational Chemistry 9 25-39, 1988. Reprinted by permission of John Wiley Sons, Inc. 

Organosilicon polymers. Silicon resembles carbon in certain respects and attempts have been made to prepare polymers combining carbon and silicon units in the molecule with the object of increasing the heat resistance of polymers. It has been found that the hydrolysis of a dialkyl-dichlorosilicane or an alkyltrichlorosilicane, or a mixture of the two, leads to polymers (Silicones), both solid and liquid, which possess great thermal stability. Thus dimethyldichlorosilicane (I) is rapidly converted by water into the silicol (II), which immediately loses water to give a silicone oil of the type (III) ... 

Some organosilicon compounds undergo transmetallation. The allylic cyanide 461 was prepared by the reaction of an allylic carbonate with trimethylsi-lyl cyanide[298]. The oriho esters and acetals of the o. d-unsaturated carbonyl compounds 462 undergo cyanation with trimefhylsilyl cyanide[95]. 

Our discussion to this point has been limited to molecules m which the chirality center IS carbon Atoms other than carbon may also be chirality centers Silicon like carbon has a tetrahedral arrangement of bonds when it bears four substituents A large number of organosilicon compounds m which silicon bears four different groups have been resolved into their enantiomers... 

V. Bazant, V. Choalovsky, and J. Rathousky, Organosilicon Compounds, Vol. 1, Chemistry of Organosilicon Compounds, Academic Press, Inc., New York, 1965. 

C. Eabom, Organosilicon Compounds, Buttersworth Scientific PubUcations, Lander, U.K., 1960. 

Organosilicone Coating Products. SiHcone products are used in a large variety of coatiags appHcatioas most prominent amoag these are siHcoae pressure-seasitive adhesives (PSA), plastic hardcoats, and paper release coatiags (398,399). 

A. D. Petrov, B. E. Mironov, V. A. Ponomarenko, and E. A. Chernyshev, Synthesis of Organosilicon Monomers, Consultants Bureau, New York, 1964,... 

V. M. Mikhaylov and V. N. Penskh, Production of Monomer and Polymer Organosilicon Compounds, English transL, No. AD-779129, NTIS, U.S. Dept, of Commerce, Springfield, Va., p. 18. 

H. W. Post, Silicones and Other Organosilicon Compounds, Reinhold, New York, 1949. 

W. NoU, lUPAC Symposium for Organosilicon Chemisty, Prague, Czechoslovakia, 1965. 

J. H. Wengrovius, T. B. BumeU, and M. A. Zumbmm, presentation at Xth International Symposium on Organosilicon Chemisty, Poznan, Poland, Aug. 

THE USE OF ORGANOSILICON ION-EXCHANGE AND COMPLEXING ADSORBENTS IN ANALYSIS OF NATURAL... 

Ion-exchange and complexing properties of organosilicon adsorbents were studied on the example of 50 elements of Periodical System. Among synthesized adsorbents it was found an effective complexation afents toward rare-earth elements. The sorption of elements is accompanied by bright display of tetradic effect. Adsorbents were synthesized, which opened wide chances of soi ption isolation and division of rare-earth elements. 

In the present time our organosilicon adsorbents found the practice application in such as fields such as, for example 1) the method of spectral-chemical determination of gold Clarke quantities in poor ores and rocks has been applied in analytic practice of geological establishments and research institutes 2) at the first time soi ption process was used in hydro-chemical analyze of fresh water. This method has been allowed to analyze of Baikal water 3) for purification metallurgical waters and waste solutions of chemical-metallurgical plants due to toxic elements 4) for creation the filters for extraction of rare elements, for example, uranium 5) for silver utilization from wasted of cinema-photo manufactory. This method has been applied to obtain the silver of high purity. 

The possibility of the existence of organosilicone compounds was first predicted by Dumas in 1840, and in 1857 Buff and Wohler found the substance now known to be trichlorosilane by passing hydrochloric acid gas over a heated mixture of silicone and carbon. In 1863 Friedel and Crafts prepared tetraethylsilane by reacting zinc diethyl with silicon tetrachloride. 

A typical condensation system involves the reaction of a silanol-terminated polydimethylsiloxane with a multi-functional organosilicon cross-linking agent such as Si(RO)4 Figure 29.8). Pot life will vary from a few minutes to several hours, depending on the catalysts used and the ambient conditions. Typical catalysts include tin octoate and dibutyl tin dilaurate. 

The RTV-1 rubbers are produced by first producing a polydialkylsiloxane with terminal hydroxyl groups. This is then reacted with a multi-functional organosilicon cross-linking agent of the type RSiX3, where X may be... 

Wengrovius, J.H., Burnell, TB. and Zumbrum, M.A. In Proceedings of the lOth Organosilicon Symposium, Poznan, Poland, August, 1993. 

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