Degradative product distribution

In order to apply ZVI-based dechlorination for site remediation, we have to be sure that no toxic reaction products are produced in the end, and toxic intermediates, if there are any, are degradable. Product distribution is controlled by reaction mechanisms. For the reduction of chlorinated methanes such as carbon tetrachloride (CT), hydrogenolysis, where chlorines are sequentially replaced by hydrogen, takes place in the presence ofZVI (Vogel etal., 1987 Matheson andTratnyek, 1994 Glod etal., 1997) ... 

Scheme 6.10. Hawker et al. s[44] cobalt catalyzed polymerization affording polyester macromolecules. The degree of branching was determined to be ca. 49% based on degradative product distribution assessment.

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, ... 

Figure 2. Molecular weight distribution of degradation products.

Enzymatic degradation of pectin can be satisfactory performed in UF-membrane reactors which have been proved to be helpful tool for laboratory scale investigations. Reaction products can be continuously recovered in a sequence of filtration stages. The obtained product distribution depends on the enzyme to substrate ratio, which affects particularly the... 

Repeat dose pharmacokinetic studies were undertaken in Sprague-Dawley rats and in monkeys. Biodistribution studies were carried out in both normal and knockout mice, with the majority of product distributed to the liver. No specific studies on product metabolism or excretion were undertaken, as the protein is almost certainly degraded via normal protein degradation mechanisms. 

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 V. Distribution of C, fenitrothion and its degradation products in individual components of aquatic model ecosystem Water and soil.

Bennett, E.R. and Metcalfe, C.D. 2000, Distribution of degradation products of alkylphenol ethoxylates near sewage treatment plants in the lower Great Lakes, North America. Environ. Toxicol. Chem. 19 784-792. 

We concentrate our effort to phytoremediation of 2,4,6-trinitrotoluene (TNT) as the main contaminant of former and present ammunition factories and to nitroesters (PETN, NG) in the Czech Republic and in Germany. In our experiments, we studied the uptake, degradation and distribution of these compounds in plants and its degradation products in plant tissues and its subsequent utilisation for real application both for soil and waste-waters cleaning. 

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