Silicon compounds synthetic applications

Physical Properties. Physical properties of importance include particle size, density, volume fraction of intrapartide and extrapartide voids when packed into adsorbent beds, strength, attrition resistance, and dustiness. These properties can be varied intentionally to tailor adsorbents to specific applications (See Adsorption liquid separation Aluminum compounds, aluminum oxide (alumina) Carbon, activated carbon Ion exchange Molecular sieves and Silicon compounds, synthetic inorganic silicates). 

It is the purpose of this chapter to review selectively the advances in the synthetic applications of organosilicon compounds, excluding those organosilanes covered in other chapters. Since the publication of The Chemistry of Organic Silicon Compounds, two monographs1,2 and several reviews3-5 have been published, as have three conference proceedings6-8 and a symposium-in-print 9. 

A few examples of DPM rearrangements in (3,y-unsaturated compounds in which the methane carbon is replaced by a boron or silicon atom have been described. However, the di-Ti-borate [14] and di-7i-silane [15] alternatives of the rearrangement do not have the scope and synthetic applications of the other alternatives mentioned before. 

In this sub chapter the most important synthetic aspect of the RCM of unsaturated organosilicon compounds will be discussed. For a general review on RCM see Refs. [59,122-124]. For a review on RCM of silyl dienes see Refs. [6,7]. A number of valuable synthetic applications have been proposed over the last few years. As follows from the data available, from the point of view of the application of RCM of vinyl and allylsilanes, the most important are silicon-tethered processes. For a general review on the silicon tethered processes see Refs. [125,126],... 

The first observation of penta- and hexaeoordinate silicon compounds was reported at the beginning of the 19th century by Gay-Lussac [87] and Davy [88], Subsequent investigation of hypercoordination in silicon compounds stimulated widespread use of nucleophilic activation and catalysis in the application of organosilicon compounds as reactive species in organic synthesis. Synthetic application for silicon-fluorine bond formation can be found in several reviews over the last two decades, and this section focuses on recent advances in the use of hypervalent organosilicon compounds in selective organic synthesis, in particular, selective carbon-carbon bond formation [89]. 

Colvin, E. W. Recent synthetic applications of organosilicon reagents. Chemistry of Organic Silicon Compounds 1998, 2,1667-1685. 

Minami, T., Nakayama. M.. Fujimoto, K., and Matsuo, S., A new approach to cyclopentane annulated compounds via l-(cyclopent-l-enylcarbonyl)vinylphosphonates, and synthesis and synthetic application of a-diethoxyphosphoryl-A Kbutenolides, Phosphorus, Sulfur Silicon Relat. Elem., 75,135,1993. 

DIN 53183 defines an alkyd resin as follows Alkyd resins are synthetic polyester resins produced by esterifying polyhydric alcohols with polybasic carboxylic acids. At least one of the alcohols must be trihydric or higher. Alkyd resins are always modified with natural fatty acids or oils and/or synthetic fatty acids. In order to obtain particular application technology properties, alkyd resins may be additionally modified with compounds such as resin acids, benzoic acid, styrene, vinyltoluene, isocyanates, acrylic, epoxy, or silicone compounds. ... 

There are a wide variety of fatty surfactants, which differ in both structure and functional properties, available to the formulator. This allows for greater formulation latitude and creation of products, which are optimized for detergent applications. The use of silicone compounds requires the synthetic modification of the molecule to make it useful in application areas where a water soluble or dispersible material is needed. Too often in the past, the formulator has had to accept many of the drawbacks of the use of silicone oils in formulations, or leave them out altogether. The ability to make friendly silicone formulator has led to the synthesis of many new silicone-based surfactants. Many of the newer detergent products already in the market contain these materials, and more wiU be in the future. 

Due to the numerous overviews on the chemistry of hypercoordinated silicon compounds, the present review is primarily focused on the structural and synthetic aspects. Spectroscopic and other properties as well as (potential) applications are only briefly mentioned in selected cases. Nevertheless, the literature on higher-coordinated silicon complexes published in the past 5 years should be covered comprehensively, while relevant older literature is also considered. 

The importance of carbon-centred radical cyclizations in organic chemistry has been documented in the large number of papers published each year and numerous reviews and books dealing with this subject. In Chapter 7 the reader can find a collection of such processes mediated by organosilanes. The silicon-centred radical cyclizations have instead received very little attention, although there has been a growing interest in silicon-containing compounds from a synthetic point of view, due to their versatility and applicability to material science. As we shall see, this area of research is very active and some recent examples show the potentiality of silyl radical cyclization in the construction of complex molecules. 

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