Reactive influence

Tetravalent silicon is the only structural feature in all silicon sources in nature, e.g. the silicates and silica even elemental silicon exhibits tetravalency. Tetravalent silicon is considered to be an ana-logon to its group 14 homologue carbon and in fact there are a lot of similarities in the chemistry of both elements. Furthermore, silicon is tetravalent in all industrially used compounds, e.g. silanes, polymers, ceramics, and fumed silica. Also the reactions of subvalent and / or low coordinated silicon compounds normally lead back to tetravalent silicon species. It is therefore not surprising that more than 90% of the relevant literature deals with tetravalent silicon. The following examples illustrate why "ordinary" tetravalent silicon is still an attractive field for research activities Simple and small tetravalent silicon compounds - sometimes very difficult to synthesize - are used by theoreticians and preparative chemists as model compounds for a deeper insight into structural features and the study of the reactivity influenced by different substituents on the silicon center. As an example for industrial applications, the chemical vapor decomposition (CVD) of appropriate silicon precursors to produce thin ceramic coatings on various substrates may be mentioned. 

TABLE 66.3. Reactivation potency of selected reactivators influenced by oxime group number and position... 

Allow the contextual representation of chemicals reactivity, i.e., reactivity influenced by the relative position of atoms, the surrounding conditions and presence or absence of specific molecules. 

If we accept, for interfacial systems, the fundamental validity of the notion of a functional group a structural subunit possessing intrinsic chemical characteristics largely independent of its nearest neighbors, then it is to be expected that those aspects of reactivity influenced by interfacial binding will be limited to certain classes of effects. These are conveniently subdivided into the catagories of composition, structure, and motion. 

The reactivity influences both the rate of reaction and the particle size distribution. Good quality hydrated limes can be made from quicklimes with a wide range of reactivities, providing the plant is correctly designed. 

A.C. ShorthaU, W.M. Palin, P. Burtscher, Refractive index mismatch and monomer reactivity influence composite curing depth, J. Dent. Res. 87 (2008) 84-88. 

Deen GR, Lim EK, Mah CH, Heng KM (2012) New cationic linear copolymers and hydrogels of N-vinyl caprolactam and N-acryloyl-N -ethyl piperazine Synthesis, reactivity, influence of external stimuli on the LCST and swelling properties. Ind Eng Chem Res 51 13354 Di Meo C, Capitani D, Mannina L, Brancaleoni E, Galesso D, De Luca G, Crescenzi V (2006) Synthesis and NMR characterization ofnewhyaluronan-basedNO donors. Biomacromolecules 7 1253... 

A total number of about 40 parameter combinations have been investigated by the procedure described to determine the reactivity influence of power level, rod insertion, inlet temperature, system pressure, vertical acceleration, breakdown of one or two pumps in the primary loop, and bumup state. The results were presented either in the form of derivatives or in some cases as a function of the parameters, which was interpolated between the calculated points. 

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