Oxygen functional groups

Figure 3. Schematic representation of the oxygen functional groups on the carbon surface (a) phenol (b) carbonyl (c) carboxyl (d) quinone (e) lactone 12].

Several mechanisms have been proposed to explain the activation of carbon surfaces. These have Included the removal of surface contaminants that hinder electron transfer, an Increase In surface area due to ralcro-roughenlng or bulld-up of a thin porous layer, and an Increase In the concentrations of surface functional groups that mediate electron transfer. Electrode deactivation has been correlated with an unintentional Introduction of surface contaminants (15). Improved electrode responses have been observed to follow treatments which Increase the concentration of carbon-oxygen functional groups on the surface (7-8,16). In some cases, the latter were correlated with the presence of electrochemical surface waves (16-17). However, none of the above reports discuss other possible mechanisms of activation which could be responsible for the effects observed. 

Fig. 5.27 Oxygen functional groups on the edge plane of graphite...

C A pitch insoluble in benzene but soluble in benzene/ ethanol azeotrope 40 Consists almost entirely of aromatic fragments attached to phenol by methylene bridges. These fragments are larger than in fraction B as they contain polyaromatic groups. It has more oxygen functional groups than B. 

Several reactions of carbonyl groups in an LPDE system have been examined. Mukaiyama aldol reactions are effectively promoted in an LPDE solution, and remarkable chelating effects of oxygen functional groups at the a-positions of aldehydes are observed (Scheme 4).16,17 Regarding... 

Due to their moderate specific surface area, carbon nanotubes alone demonstrate small capacitance values. However, the presence of heteroatoms can be a source of pseudocapacitance effects. It has been already proven that oxygenated functional groups can significantly enhance the capacitance values through redox reactions [11]. Lately, it was discovered that nitrogen, which is present in carbon affects also the capacitance properties [12]. 

Georgakis, M., G. Stavropoulos, G.P. Sakellaropoulos, Molecular dynamics study of hydrogen adsorption in carbonaceous microporous materials and the effect of oxygen functional groups. Int. J. Hydrogen Energ. 32(12), 1999-2004, 2007. 

YS-822A had nine degrees of unsaturation, all of which have already been assigned to four double bonds, two carbonyls (a lactone and a carboxylic acid) and three rings. Consequently, all the oxygen functional groups at C should be hydroxyls. Thus, the planar structure of YS-822A was determined as 65. 

These diterpenoids, although not cyclic polyethers, do contain several oxygen functional groups and may assume conformations which could favor the formation of such complexes. 

III. PEROXIDES WITH SINGLE-BONDED OXYGEN FUNCTIONAL GROUPS... 

TABLE 2. Enthalpies of formation of hydroperoxides and peroxides containing single-bonded oxygen functional groups (kJ mol )... 

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