Possible reactions

Write a possible reaction sequence for the photochemical oxidation of aqueous CN ion on Ti02. 

Example Researchers have used MX DO and. AMI setn i-etn pirical methods It) calculate possible reaction pathways for the interae-... 

Rather than using transition state theory or trajectory calculations, it is possible to use a statistical description of reactions to compute the rate constant. There are a number of techniques that can be considered variants of the statistical adiabatic channel model (SACM). This is, in essence, the examination of many possible reaction paths, none of which would necessarily be seen in a trajectory calculation. By examining paths that are easier to determine than the trajectory path and giving them statistical weights, the whole potential energy surface is accounted for and the rate constant can be computed. 

Synthesis of a peptide of prescribed sequence requires the use of pro tectmg groups to minimize the number of possible reactions... 

At first glance it appears that these systems do conform fully to the discussion above this is an oversimplification, however. The ortho and para hydrogens in phenol are not equal in reactivity, for example. In addition, the technology associated with these polymers involves changing the reaction conditions as the polymerization progresses to shift the proportions of several possible reactions. Accordingly, the product formed depends on the nature of the catalyst used, the proportions of the monomers, and the temperature. Sometimes other additives or fillers are added as well. 

Among other possible reactions, these free radicals can initiate ordinary free-radical polymerization. The Ziegler-Natta systems are thus seen to encompass several mechanisms for the initiation of polymerization. Neither ionic nor free-radical mechanisms account for stereoregularity, however, so we must look further for the mechanism whereby the Ziegler-Natta systems produce this interesting effect. 

Tritium is produced in heavy-water-moderated reactors and sometimes must be separated isotopicaHy from hydrogen and deuterium for disposal. Ultimately, the tritium could be used as fuel in thermonuclear reactors (see Fusionenergy). Nuclear fusion reactions that involve tritium occur at the lowest known temperatures for such reactions. One possible reaction using deuterium produces neutrons that can be used to react with a lithium blanket to breed more tritium. 

The dianilinopolycarhocyanines, CgH5HN=CH-(-CH=CH NHCg Hg, are useful synthetic iatermediates for polymethine dyes, offering needed spectral and other properties (3,4,73,74). The asymmetrical polymethines appear to be ambivalent systems, and the number of possible reaction paths iacreases considerably as a result (75,76). 

Carbonate values are usually suppHed from soda ash or carbon dioxide or an equimolar mix. Possible reactions are... 

Techniques for the synthesis of reaction paths on the basis of enumeration of all possible reactions are fairly weU developed. The SYNCHEM2 system conducts a backward search of possible reaction paths from a desired product (76). Because the procedure is limited by the rapid growth of... 

An alternative approach (78,79) is based on a set of possible reaction schemes that are used to generate potential new pathways. Under both approaches, the problem, in part, is how to evaluate the utiUty of a particular scheme. A computer-assisted approach to predicting potentially useful reactions has been developed (80). The union of existing capabiUties in modeling chemical stmctures with selecting reaction pathways has not yet taken place. 

All of the atomic species which may be produced by photon decomposition are present in plasma as well as the ionized states. The number of possible reactions is therefore also increased. As an example, die plasma decomposition of silane, SiH4, leads to the formation of the species, SiH3, SiHa, H, SiH, SiH3+ and H2+. Recombination reactions may occur between the ionized states and electrons to produce dissociated molecules either direcdy, or tlrrough the intermediate formation of excited state molecules. 

Alternative algorithms employ global optimization methods such as simulated annealing that can explore the set of all possible reaction pathways [35]. In the MaxFlux method it is helpful to vary the value of [3 (temperamre) that appears in the differential cost function from an initially low [3 (high temperature), where the effective surface is smooth, to a high [3 (the reaction temperature of interest), where the reaction surface is more rugged. 

In the antisymmetric case the possible reaction path ranges from the MEP (when cui and coq are comparable) to the sudden path (coi <4 coq), when the system waits until the q vibration symmetrizes the potential (the segment of path with Q = Qo) and then instantaneously tunnels in the symmetric potential along the line q = 0. All of these types of paths are depicted in fig. 17. ... 

Care should be exercised when sampling for aerosols that are condensable. Some separating systems, such as wet impingers, may remove the condensables from the gas stream, whereas others, such as electrostatic precipitators, will not. Of equal concern should be possible reactions in the sampling system to form precipitates or aerosols which are not normally found when the stack gases are exhausted directly to the atmosphere. SO-,... 

VinylmetlQfleneeyelopropane rearranges in the gas phase to 3-metlQflenecyclopen-tene. Two possible reaction mechanisms are ... 

Despite the fact that the two main components of UF-resins are urea and formaldehyde, a broad variety of possible reactions and structures in the resins can be obtained. At the molecular level, the basic characteristics of UF-resins can be explained as follows (1) high reactivity (2) water solubility and dispersibility, which renders the resins ideal for use in the woodworking industry and (3) the reversibility of the aminomethylene link, which also explains the low resistance of the UF-resins against the influence of water and moisture, especially at higher temperatures. This is also one of the reasons for the subsequent formaldehyde emission. 

We will return to our consideration of RIP diagrams. Figure 5-22 summarizes the possible reaction paths. Recall that an intermediate is a state of minimum energy on the reaction path, so that all four comers may constitute energy minima, but for any given type of reaction it is unlikely that both I and 1 will be of comparable stability. As Table 5-3 indicates, one of these is apt to be the favored intermediate. 

A strong argument in favor of the proposed mechanism (23) over other possible reaction pathways is that the enhanced driving force, present in the... 

When sulfide ores are roasted in air two possible reactions may occur ... 

The simple ring opening of tetrahydro-1,3-oxazine derivatives is not the only possible reaction of these heterocyclic compounds catalyzed by mineral acids. An interesting rearrangement of 6-aryl-6-alkyltetrahydro-l,3-oxazines when warmed with concentrated hydrochloric acid was found by Schmiedle and Mansfield ... 

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