Degradation product distribution from

Limited information is available regarding the nature of the degradation products formed from silicone surfactants, although characteristic aspects of silicone chemistry (i.e. influence of chain length and ring size on compound stability) [23,29] can be used to aid prediction of product formation and distribution. 

Table VIII. Product Distribution from the Catalyzed and Noncatalyzed Degradation of Asphaltene...

K. Taknma, Y. Uemichi and A. Ayame, Product distribution from catalytic degradation of polyethylene over H-gallosilicate, Applied Catalysis A, 192, 273-280 (2000). 

The product distribution from the reaction of geraniol (1) was also similar to that which is known to result from acid-catalyzed degradation of naturally occurring linalyl and geranyl glycosides in fruit juices and wines (7 7). 

Polystyrene - Thermal degradation is the simplest of the current techniques used to recover feedstock chemicals from styrene-based polymers and has therefore been studied extensively. Investigations of the product distributions from thermal degradation of polystyrene have mainly focused on liquid products. It has been observed that the yield and the composition of liquid products vary strongly with temperature and the reactor configuration,... 

ViUanueva, F., I. Barnes, E. Monedero, S. Salgado, M.V. Gomez, and P. Martin (2007), Primary product distribution from the Cl-atom initiated atmospheric degradation of furan Enviromnental implications, Atmos. Environ., 41, 8796-8810. 

Nonicosahedral carboranes can be prepared from the icosahedral species by similar degradation procedures or by reactions between boranes such as B H q and B H with acetylenes. The degradative reactions for intermediate C2B H 2 species (n = 6-9) have been described in detail (119). The small closo-Qr Yi 2 species (n = 3-5 are obtained by the direct thermal reaction (500—600°C) of B H using acetylene in a continuous-flow system. The combined yields approach 70% and the product distribution is around 5 5 1 of 2,4-C2B3H2 [20693-69-0] to l,6-C2B Hg [20693-67-8] to 1,5-C2B3H3 [20693-66-7] (120). A similar reaction (eq. 60) employing base catalysts, such as 2 6-dimethylpyridine at ambient temperature gives nido-2 >-(Z, ... 

It should be emphasized that virmaUy all of the above discussion is based on biomimetic chemistry, where the Fe(II) source varies from salts such FeS04 to the more reactive FeCla-THaO as well as heme mimetics (TPP) and ester hematin variants. When heme models are used, since porphyrin alkylation is a favoured process, end-product distributions of products can be very different from when a free ferrous ion source is employed. Furthermore, solvent has been shown to have a profound effect on the rate of reaction and product distributions obtained in iron-mediated endoperoxide degradation. Thus all of these studies are truly only approximate models of the actual events within the malaria parasites. Future work is needed to correlate the results of biomimetic chemistry with the actual situation within the parasite. In general, most workers do accept the role of carbon-centred radicals in mediating the antimalarial activity of the endoperoxides, but the key information defining (a) the chemical mechanism by which these species alkylate proteins and (b) the basis for the high parasite selectivity remains to be unequivocally established. 

The toxicity of the degradation products may exceed the toxicity of the parent compounds. Heavy metals are converted to less soluble forms they are not removed from the subsurface. Heterogeneities in the subsurface may cause the uneven distribution of nutrients during direct-injection applications. Injection may be slower in formations with low hydraulic conductivities. Smaller reactive zones may also form in areas with low hydraulic conductivities. 

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