Graphite intercalates selectivities

In 1976, Lalancette et al. studied228 the catalytic activity of graphite intercalated AICI3 and compared it with neat AICI3 in solution-phase alkylations. Whereas the rate of alkylation slowed down using the intercalated catalyst, a higher selectivity toward monoalkylation was found (Table 5.13). 

Table 1. Selected non-commensurate graphite intercalates" (Lattice vectors in A, angles in degrees.)... 

The electronic character of the stacked aromatic systems makes it possible for atoms or molecules to slip between these layers, either accepting or donating electrons to bond with the carbon system, a process referred to as intercalation. Platinum metal graphite intercalates have been prepared by reducing platinum halide graphite intercalates. These catalysts are particularly useful for the selective hydrogenation of acetylenes to cis alkenes (Eqn. 9.3).22... 

Water J, Shioyama H (1999), Boron trichloride graphite intercalation compormd studied by selected area electron diffraction and scanning tunneling microscopy , J Phys Ghent Solids, 60, 737-741. 

This section summarizes some of the most significant electrochemical results obtained to date for selected electrodes cleaned and characterized under UHV in PEO-lithium-based solutions, and include nonalloy (Ni)- and alloy-forming metals (Ag and Al), a noninteracting substrate (boron-doped diamond, BDD) and a material capable of intercalating Li+ (graphite). It is expected that the information herein contained will serve to illustrate the power of this methodology for the study of highly reactive interfaces. 

Table 12.3 Superconducting Critical Temperatures Tc(Kelvin, at 1 bar) or Tc (Kelvin) at Applied Pressure P(kbar) for Selected Organic, Intercalated Graphite, (SN)X, and Fulleride Superconductors3...

Lalancette et al. described the preparation of chromium(VI) oxide intercalated in graphite and its use as a selective oxidant for primary alcohols to aldehydes (Table 17). Secondary and tertiary alcohols are inert under the reaction conditions, but 1,2-diols are cleaved. However, Ebert and coworkers demonstrated that Lalancette probably used CriOg rather than chromium(VI) oxide intercalated gnq ite for these oxidations. This reagent does appear to show the properties described by Lalancette et al. Indeed, when Kagan and coworkers prepared fully characterize chromium(VI)-inteieiated gnqihite it appeared to lack any oxidative properties. ... 

Considering adsorption as the first step in catalysis, both physical and chemical adsorption has been observed with intercalates. Watanabe et a/. have shown that selective adsorption based on molecular size occurs with potassium-, rubidium-, and caesium-graphite. The molecular sieve properties are not as distinctive as in zeolites, as a result of the comparatively easy expandability of the layers. Once the gas enters the layers, both chemisorption and chemical reaction is possible. Therefore, for example, adsorption... 

It is interesting that at variance with these conclusions, Volta et. al. (38, 39), studying oriented samples of MoO, obtained from intercalation compounds of MoCl - graphite, concluded that selective oxidation of propylene to acrolein or isobutene to niethacrolein is mainly catalysed by the (100) side faces, whereas the (010) basal race is responsible for total oxidation. It should be remembered, however, that selective oxidation is a multistep process, consisting of the consecutive abstractions of hydrogen atoms and insertion of oxygen atoms. As already described, experiments with allyl compounds (15) showed... 

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