Catalytic effect of graphite

The catalytic effect of graphite A thus depends on iron impurities, e. g. Fe304, and probably also on iron sulfides or sulfates, because sulfur is also present in this graphite, and all these iron compounds are known catalysts of FC acylation [69, 73, 74], In this respect, it seems that FeCl3 could be the true catalyst generated in situ by the reaction of the different iron compounds with acid chloride and hydrogen chloride. In the... 

The retentive power of graphite towards adipic acid and the catalytic effect of the magnetite, especially present in A, are obvious. TEM examinations of a graphite A sample before and after reaction showed that crystallites of Fe304 appeared to be smaller after the reaction. However, the same graphite sample was reused for three successive reactions without significant loss in yield. When applied to the synthesis of other cyclic ketones (Scheme 7.14), less volatile than 74, it was observed that pressure had an effect on the recovery of product (Tab. 7.9, entries 3 and 4). A slightly reduced pressure (300 mm Hg) was necessary to obtain 3-methylcyclopentanone (75) or cyclohexanone (76) in convenient yield (Tab. 7.9, entries 4 and 5). For the cycliza-tion of suberic acid (73), a less favorable structure, the yield in cycloheptanone (77) remained low (Tab. 7.9, entry 6). 

Heintz, E.A. and Parker, W.E., Catalytic effect of major impurities on graphite oxidation, Carbon 4, 473-82 (1966). 

The retentive power of graphite towards adipic acid and the catalytic effect of the magnetite, especially present in A, are obvious. TEM examination of a graphite A before and after reaction showed that crystallites of Fe304 seemed to be smaller... 

When carbon nanotubes (CNTs, which are effectively rolled up graphene structures) were first utilised in electrochemical applications they were found to contain metallic impurities as a result of their CVD fabrication, which contributed or dominated their observed electrochemical response [59, 60]. Similarly, it has been shown that graphene fabricated from graphite, via chemical oxidation of natural graphite followed with thermal exfoliation/reduction, can contain cobalt, copper, iron, molybdenum and nickel oxide particles which can influence the electrochemistry of graphene towards specific analytes and has potential to lead to inaccurate claims of the electro-catalytic effect of graphene [61, 62]. 

Figure 10.2. NEMCA in H2 oxidation on Pt/graphite in 0.1 M KOH Steady-state effect of applied positive (anodic) current (I) on the increase in the rates of hydrogen ( ) and oxygen (O) consumption Ph2=0.8 kPa, po2 L25 kPa r 2 (=rg =rc°)=2,38xl0 7 mol/s is the open-circuit catalytic rate Fv=540 cm3/min at STP. Reprinted with permission from Nature, McMillan Magazines Ltd.3...

The catalytic rate of hydrogenase adsorbed on the graphite electrode was measured by potential step chronoamperometry, in which cnrrent is monitored throughout a fixed sequence of potentials. This allows for direct observation of hydrogen oxidation activity at a particular potential over a period of time. Figures 5.14 and 5.15 show how chronoamperometry can be used to study the kinetics of reductive activation and oxidative inactivation respectively. A series of oxidative inactivation curves from several experiments like that shown in Fig. 5.14, showing the effect of pFl on oxidative inactivation, are shown in Fig. 5.15. The kinetics of the reactivation process can be... 

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