By different synthetic

The industrial production of fatty acids on the basis of petrochemical raw materials is of secondary importance in comparison with their preparation from natural materials. Only short-chain or branched or odd-numbered carboxylic acids, for which natural sources don t exist, have to be prepared by different synthetic methods. 

Figure 2.5. Scheme of the preparation of EDT-TTF by different synthetic routes (strategies S2, S3, S4 and S5). Increasing arrow width indicates higher selectivity (S4 is completely selective). 

As mentioned above, rat liver cytosol contains one or more factors that stimulate microsomal iodothyronine deiodinase activity. It has been realized for more than a decade now that the enzymatic deiodination of iodothyronines is a reductive process which is supported by different synthetic and natural SH compounds [48]. Most investigations of the catalytic mechanism of the deiodinase have utilized artificial cofactors such as the dithiol DTT. The results have demonstrated that both ORD and IRD follow ping-pong type reaction kinetics, indicating that the enzyme exists in two alternating forms induced by the reactions with substrate and cofactor [7,8]. 

Synthesis of Silica. Silica used in HPLC is an amorphous, porous solid, which could be obtained by different synthetic procedures. 

When studying commercial surfactants obtained from different suppliers and possibly manufactured by different synthetic routes, variations in hydrophobe carbon number distribution, hydrophobe chain branching, the distribution of ethylene oxide chain lengths about the average value, and the nature and concentration of impurities has to be considered. 

Examples are known (22-25) of the oxidation of macromolecular substrates containing sulfide functional groups, with chiral polysulfoxides being prepared by different synthetic approaches ( 6,27.). However, the asymmetric oxidation of polymeric precursors was only performed with very limited degrees of chemoselectivity and enantioselectivity (27). The asymmetric oxidation reaction employed in this work is accomplished with a moderate enantioselectivity, which is nevertheless on the order of magnitude as those obtained with low molecular weight substrates (11.28.29). 

Organotitanium alkoxides are a subject of continuing interest with respect to structure and reactivity. Several monoalkoxo complexes CpTiCl2(OR) (R = alkyl, aryl) have been prepared by different synthetic procedures. Pure final products can be isolated if the R groups are bulky. Particularly good yields are obtained for phenoxo complexes with 2,6-diisopropyl substituents. Electrochemical studies of the complexes in dry THF have been carried out.831... 

The studies of elementary films formed in inverse emulsions and stabilized by different synthetic and natural surfactants revealed that the membrane electric conductivity experiences a sharp increase upon the addition of some biologically active surfactants. For instance, membrane conductivity may increase by five orders of magnitude when trace amounts of valinomycin antibiotic are introduced into the outer aqueous medium of lipid membrane. At the same time the membrane becomes permeable to potassium and hydrogen ions but impermeable to sodium ions. A sharp decrease in electric resistance of synthetic membranes is observed when proteins and enzymes with suitable substrates are introduced into them. By studying the properties of such membranes one may model important biological processes, e.g. the transfer of neural impulses. 

Fig. 55. Effect of calcination (5h at the indicated temperature) on powder XRD patterns of Ce0.6Zr0 4O2/Al2O3 samples prepared by different synthetic methods. XRD patterns are subtracted from the A1203 contribution. (1) proprietary sample (2) co-impregnated sample. (Di Monte et al. 1998a.)...

Figure 4. Activation of the complement system by different synthetic materials incubated with rabbit plasma. (Reproduced with permission from Ref.. 26. Copyright 1984 Wiley.)...

Methyl-branched fatty acids are found in lipid fractions of many plants and are very common in bacterial extracts. Sixteen branched fatty acids were produced by different synthetic methods, including alkylation and hydrolysis of oxazolines to obtain 2-alkyl fatty acids. This was achieved through desulfurization of alkyl-substituted thiophenecarboxylic acids for 4- and 6-alkyl fatty acids and the application of the Kolbe reaction of dioic acids to give alkyl branches at different positions of the chain... 

Aryl chlorides, as the least reactive halides, can be cross-coupled with arylboronic acids by different synthetic methods. Each particular method must include an apropriate catalyst, capable to react with rather unreactive C-Cl function to give a... 

The exact detail and makeup of the polymer backbone will determine whether the polymer is capable of crystallizing. This microstructure can be controlled by different synthetic methods. For example, Ziegler-Natta catalysts are capable of controlling the microstructure to produce stereospecific polymers. 

Fig. 20.20 Trends in size increase vs. thermal curing of the samples prepared by different synthetic conditions (Adapted with permission from Callone et al. 2007, Copyright 2007 Cambridge University Press)...

The highest oxide of U that is known is the yellow/orange UO3. It can be prepared by different synthetic approaches, one being the treatment of lower oxides with high-pressure oxygen at modest temperatures (e.g., 300°C) another is the thermal decomposition of hydrated uranyl salts at temperatures below 650°C. In air, UO3 loses oxygen when heated above 650°C to form U3O8. There are several different crystal modifications of UO3 (see table 25). 

Because chemical and structural properties of natural and artificial gems are very similar in this case, the possibilities of Raman and LIBS methods are rather limited. It was found that other laser-based techniques could be very effective for rapid spectroscopic discrimination between natural and synthetic emeralds, rubies, and alexandrite (Armstrong et al. 2000). The first one is DRIFTS (Diffuse Reflectance Fourier Transformed Infra-Red Spectroscopy) and the second one is NIR (Near Infra-Red) Spectroscopy. In some cases it was even possible to discriminate between gems made by different synthetic processes. Once again, there is a significant benefit to having two independent methods available. 

POLYACETYLENE AND ITS ANALOGS Table III. Properties of PA Made by Different Synthetic Routes... 

Different polymer types are obtained by different synthetic methods. 

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