Occurrence sulfur content

The occurrence of vanadium in the lower oxidation states, which as the simple aqua ions undergo acid dissociation above pH 3 [if present as V(III)) ] and pH 6 [in the case of oxo-V(IV) ], along with the high sulfur content of ascidian blood and the low pH that results when ascidian blood cells are ruptured in distilled water has led to the belief that intact vanadium-containing tunicate blood cells are acidic (145). Other lines of evidence, including vital staining and NMR (144,170), and... 

Unlike their benzene counterparts, thienopyridines do not occur widely in nature. The basic components of a shale oil of high sulfur content were found to contain certain methylthieno[2,3-6]- and -[3,2-6]-pyridines, but no other natural occurrence of the compounds has been reported. 

In contrast to the above-mentioned occurrence of polioencephalomalacia in beef cattle consuming a diet with a sulfur content > 5 g kg no clinical symptoms have been observed in pigs, goats, heifers and fattening bulls receiving a diet supplemented with lOgSkg (Anke et al. 1992). However,... 

Complications may also arise in the case of coals with high moistme and sulfur content and those with tendencies to degrade when exposed to aerial oxygen. This is a critical issue in the case of low-rank, high-sulfur coals. Lignite and snbbitnminons coal are difficult to store without occurrence of spontaneous combustion, in contrast to anthracite where the potential for spontaneous ignition to occur is minimal. 

The occurrence of cyclic structures also depends on the sulfur content of initial polysulfides the lower the sulfur content is, the more cyclic structures are formed. For this reason, to yield polysulfide polymers, the use of sodium tetrasulfide is preferred to sodium disulfide. More than 100 different monomers have been used [8-15], and based on experimental data, an attempt was made to establish reactivity-structure correlation. For halide derivatives, the most reactive are allylic and benzylic halide derivatives the primary derivatives are more active than the secondary or tertiary derivatives. As far as industrial monomers are concerned, 1,2-dichloroethane is more active than 2,2-dichloroethane or 2,2-dichlorodiethyl formal. 

Opening an unused but old commercial ampoule of the ice-cooled bromide led to eruption of the decomposed contents [1]. Similar occurrences on 2 occasions were reported later [2], though on both occasions hexabromonaphthalene was identified in the residue (suggesting contamination of the bromide by naphthalene as an additional source of internal pressure). Sulfinyl bromide is of limited stability, decomposing to sulfur, sulfur dioxide and bromine, and so should be stored under refrigeration and used as soon as possible. 

The distributions of minerals within the Lower Kittanning seam can be related to depositional environment. Pyrite content is highest in areas which may have experienced brackish conditions. This distribution reflects the availability of iron and sulfur, and pH conditions within the swamp. Whereas much of the pyrite formed syngenetically, observations of sulfide modes of occurrence suggest that marcasite formed epigenetically. 

---