By functional group analysis

Securinine, the major alkaloid in the leaves of Securinega suffruticosa (Pall.) Rehd. was first described by Murav eva and Bankovskii (10, 11). These Russian workers determined the empirical formula (CisH gNOg) and some other physical properties of securinine and prepared a series of derivatives. They also established the absence of A-methyl, 0-methyl, hydroxyl, methylenedioxy, and ketone groups by functional group analysis and the presence of a lactone moiety and extended conjugation by IR and UV spectroscopy (12). The skeletal structure was first established independently and almost simultaneously by two Japanese teams on securinine isolated from domestic S. suffruticosa plants (13, 14). Subsequently, securinine was also isolated from... 

High-molecular-weight aliphatic amines are used extensively in many industries. The total primary- and secondary-amine content of aliphatic amines can be determined easily and rapidly by functional-group analysis in the near infrared [9], using chloroform solvent and 5-cm fused-silica cells. Primary amines have characteristic absorption maxima at 2.02 /um and 1.55 m, whereas secondary amines absorb only at 1.55 fim. Quantitation is achieved by the calibration-curve method using a series of standard solutions of primary and of secondary amines. Most other methods for the determination of total primary, secondary, or tertiary amine in a mixture are lengthy or inaccurate, or are unsuitable for small samples. 

Functional Group Analysis. The total hydroxyl content of lignin is determined by acetylation with an acetic anhydride—pyridine reagent followed by saponification of the acetate, and followed by titration of the resulting acetic acid with a standard 0.05 W sodium hydroxide solution. Either the Kuhn-Roth (35) or the modified Bethge-Liadstrom (36) procedure may be used to determine the total hydroxyl content. The aUphatic hydroxyl content is determined by the difference between the total and phenoHc hydroxyl contents. 

Flammability Timits. Some 1358 compounds selected from the DIPPR Compilation Pile (Peimsylvania State University, 1991 Ref. 4) have been fit for upper and lower flammabiHty limits (227). Average errors reported were 0.266% (volume) and 0.06% (volume) for upper and lower flammabiHty limits, respectively. A detailed analysis by functional group classification is included that identifies classifications with high error for several methods. 

N. D. Cheronis and T. S. Ma, Organic Functional Group Analysis by Micro and Semimicro Methods, Interscience, New York, 1964, p. 494. 

A number of ex situ spectroscopic techniques, multinuclear NMR, IR, EXAFS, UV-vis, have contributed to rationalise the overall mechanism of the copolymerisation as well as specific aspects related to the nature of the unsaturated monomer (ethene, 1-alkenes, vinyl aromatics, cyclic alkenes, allenes). Valuable information on the initiation, propagation and termination steps has been provided by end-group analysis of the polyketone products, by labelling experiments of the catalyst precursors and solvents either with deuterated compounds or with easily identifiable functional groups, by X-ray diffraction analysis of precursors, model compounds and products, and by kinetic and thermodynamic studies of model reactions. The structure of some catalysis resting states and several catalyst deactivation paths have been traced. There is little doubt, however, that the most spectacular mechanistic breakthroughs have been obtained from in situ spectroscopic studies. 

Photodiode array detection has three major advantages for HPLC analysis (26) (a) multiple-wavelength detection, (b) peak identification, and (c) peak-purity determination. Since PDA can record the characteristic UV spectra of the different phenolics as they elute from the column, characterization and peak-purity information can be facilitated through comparison of the spectra at the front, the apex, and the tail of each peak. Furthermore, the rapid calculation of absorbance ratios between different wavelengths is possible, which can be used to classify the spectra by functional groups or by other criteria (Table 1). 

Application of gas chromatographic/mass spectrometric analysis to acidic/basic subfractions of coal-derived asphaltenes has led to the conclusion that the asphaltenes are made up of one-ring and/or two-ring aromatic units that are linked by methylene chains as well as by functional groups (Koplick et al., 1984). Projection of this finding to coal itself is of interest only if it can be assumed that the intemuclear bonds withstood the high temperatures and were not formed as a result of secondary and tertiary (etc.) reaction. In short, the question relates to the relationship of the structural types in the asphaltenes to those in the original coal. 

Dimethoxycanthin-6-one has been isolated from Picmsma ailan-thoides Sieb et Zucc. (Simarubaceae), and its structure was established by recognition of the characteristic UV-spectrum, functional group analysis, and oxidation to /J-carboline-1 -carboxylic acid (10). 

A degree of polymerization of about ten was determined by end-group analysis via H-NMR. Glass transitions were found to occur below room temperature. In each case, the material was smectic at 80 The polymers exhibited a broad enantiotropic phase range. A uniaxial teflon monolayer gave well-aligned parallel samples which were used to determine the smectic tilt angle as a function of temperature. The materials were well-behaved... 

Another technique which is widely used for functional group analysis of humic materials is carbon-13 nuclear magnetic resonance specroscopy ( C-NMR). The C-NMR solid-state spectrum of an aquatic humic acid is shown in Figure 5. The band assignments for the types of carbon that can be detected by NMR are listed in Table III. Again, bands are broadened due to the presence of free radicals in the structure. More information can be obtained with C-NMR regarding the carbon skeleton of the humic... 

Ma, T. S., and Athanasios S. Ladas. Organic Functional Group Analysis by Gas Chromatography. The Analysis of Organic Materials, no. 10. New York Academic Press, 1976. 

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