Saturates terminally branched

Sample Terminally branched saturates Mono- unsaturates Poly- unsaturates Sat. Branched mono- unsaturates Mid-chain branched saturates Satur- ates Total fatty acid (ng/g organic C)... 

Figure 7.18 Variation in microbial community structure and indicators of environmental stress within different parts of the concretion and host sediment from profile 93LD (a) community structure -TBS = terminally branched saturates, MBS = mid-branched saturates Poly = polyenoics, Total Mono = total monoenoics, BMono = branched monoenoics. Sedi-far represents the host sediment at some distance from the concretion but at the same stratigraphic level (b) indicators of nutritional stress (c) biomarkers for Desu/fobacfer<10Me16 0) and Desulfovibrio

Saturated fatty acids may be envisaged as based on acetic acid (CId3—COOH) as the first member of the series in which —CHj— is progressively added between the terminal CHj— and —COOH groups. Examples are shown in Table 14-1. Other higher members of the series are known to occur, particularly in waxes. A few branched-chain fatty acids have also been Isolated from both plant and animal sources. 

One of the mechanisms proposed recently for the photooxidation of PVC involves the formation of methyl radicals from the ends of branches and chains (94). It is extremely difficult to understand how such radicals could be produced, since all of the saturated chain ends and branch ends identified thus far contain a terminal chloromethyl arrangement (see above). 

Generally a linear hydrocarbon chain with a terminal carboxyl group, a fatty acid can be saturated or unsaturated. Branched-chain phytanic acid is found in dairy products. An inability to degrade phytanic acid causes its accumulation in plasma and tissues (Refsum disease). 

Linear systems with an NO3 donor set are exemplified by simple saturated molecules, which show preferences toward lighter, higher charged metal ions, such as linear (90). Branched systems include tripodal ligands having different central atoms and 0-donors terminating the chains, for example, (91) and (92). Their coordination chemistry is partly directed by their shape, which tends to support trigonal... 

Irradiation of Marlex 6003 Polyethylene. Results of 13c NMR measurements on Phillips Marlex 6003 polyethylene both prior to and just following a 2.0 Mrad irradiation in vacuum and 298 K are presented in Table IV. The spectra from which these data were obtained are shown in Figures 4 and 5. These results indicate that irradiation of high density polyethylene in vacuum in the solid state reduces the concentration of terminal vinyl unsaturations and increases the concentrations of long chain Y branches, saturated end groups and trans double bonds. The H-link could not be detected following an irradiation of Marlex 6003 in the solid state. 

Figures 9 and 10. The results for NBS 1475 are similar to those obtained from the study of Marlex 6003 after irradiation in the solid state. Once again, the concentrations of long chain Y branches, saturated end groups and trans double bonds apparently increase with irradiation while the concentrations of terminal vinyl groups decrease with irradiation. There is some scatter in the data as might be expected for concentrations measured in the range of 1-3 per 10,000 carbon atoms. As was the case for Marlex 6003, the presence of any appreciable quantity of H-links was not detected. Thus the H-link concentration must be well below one per...

Compound C. The mass spectrum again showed the common anacardic acid ions, and a molecular ion of m/z 362, which suggested that Compound C was a C21 saturated anacardic acid. The nmr spectrum also indicated that C was saturated, and the terminal methyl signal at 80.85ppm was complexed and represented 6 protons. Hence C was identified as a C21 branched chain anacardic acid, and by comparison with the nmr spectra of iso and anteiso branched chain fatty acid standards, the terminal methyl signal was identical to the terminal methyl resonance of an anteiso group, thus C is in all probability the C21 anteiso saturated anacardic acid. 

Compound F. A molecular ion at m/z 376 and the knowledge that the retention time of F was slightly earlier than G, which was already known as the C22 straight chain saturated anacardic acid, strongly suggested that Compound F was a C22 branched chain saturated anacardic acid. The nmr of the terminal methyl signal (50.83ppm) showed it contained 6 protons, and was split into a simple doublet, consistent with an iso type end chain. Hence F is the C22 iso saturated anacardic acid. 

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