Potassium graphite intercalates

Yang, M. H. and P. C. Eklund. 1988. Optical dielectric function of high-stage potassium graphite intercalation compounds Experiment and theory. Phys. Rev. B 38 3505-3516. 

Takahashi, T., H. Tokailin, T. Sagawa, and H. Suematsu. 1985. Angle-resolved ultraviolet photoemission study of potassium-graphite intercalation compound C8K. Synth. Metals 12 239-244. 

Reaction of methyl or ethyl benzoate with the potassium-graphite intercalation compound CsK, in DME or THF under argon at 25 "C, followed by quenching with water and air oxidation, gives a 30% yield of phenanthraquinone (equation 3). The conversion of benzoin into phenanthraquinone by CkK at the layer edge of the intercalate, with loss of molecular hydrogen, had been described earlier. The overall process (equation 3) has been described by its discoverers as the hyperacyloin condensation. The conversion of methyl 4-alkylbenzoates into 3,6-dialkylphenanthraquinone has also been reported. ... 

The Potassium-Graphite Intercalate (CgK) is prepared as follows In a three-necked round bottomed flask flushed with argon and equipped with a magnetic stirrer, graphite (1-2 g) is flame dried and heated to 200 °C. After 15 min, K (0.5 g) is added in small pieces and the stirring at 200 °C is continued until the bronze-colored CgK is formed. The reagent is cooled to room temperature and kept under argon. 

Lalancette J M, Roussel R (1976), Metals intercalated in graphite. I. The reactions of aromatic, olefinic, and acetylenic hydrocarbons with potassium-graphite intercalates . Can J Chem, 54, 2110-2115. 

Potassium Graphite. Potassium, mbidium, and cesium react with graphite and activated charcoal to form intercalation compounds CgM, C24M, C gM, C gM, and C qM (61,62). Potassium graphite [12081 -88-8] 8 P gold-colored flakes, is prepared by mixing molten potassium with graphite at 120—150°C. 

Fig. 16.4 Staging n graphite intercalation compounds, C j K Adchtkm of potassium proceeds through = 4.3. 2. to the h lrat in stage I Cij K - C K. From Whillingham, M. S. Dines, M. B. Surr. Prop. Chcm. 1980. 9, 55. Reproduced with permission. ...

Wang, G., P. K. Ummat, and W. R. Datars. 1988. De Haas-van Alphen effect of potassium intercalated graphite. Extended Abstracts, Graphite Intercalation Compounds, 217-219, Materials Research Society, Fall Meeting, Pittsburg, PA. 

The reaction of various carbonaceous materials with steam to yield CO, CO2, and H2 has been intensively studied. Of special interest has been the catalysis of this reaction by various alkali metal containing compounds, most notably potassium carbonate (32-37). Various mechanisms have been proposed, some including alkali metal atoms (37) or even graphite intercalation compounds (38) as intermediates. 

In addition, the reactivity of Zintl ion solntions with layered materials have been reported. Solntions of IQSng in enrednce graphite and Hffe the potassium is intercalated into the structure and tin metal is deposited on the edges of the layered... 

The structure of the intercalates are of considerable interest, in that the intercalate material enters the graphite layers to form in the final analysis, a one-to-one graphite-intercalate layer structure. Intermediate compounds involve inclusion of the material in, for example, a second, fourth, or fifth layer rather than dilution of the amount in the same layer. The chemical bonding in the compounds appears to be ionic and certainly involves electron transfer probably, for example, from potassium to the upper pi-band of graphite. ... 

Fig. 6 The Stage 1 graphite intercalation compound of potassium KCg. (View this art in color at www.dekker.com.)...

In this case a potassium-graphite (KCg) electrode has been used as the carbonaceous anode material. Upon anodic polarisation this electrode irreversibly deintercalates potassimn resulting in a graphite-like compound, which on subsequent cycles performs with fast kinetics of its lithium intercalation-deintercalation process [89, 90]. Accordingly, the first charging process of the battery may be written as shown in Equation 7.7 at the anode. 

The nuclear magnetic resonance spectroscopy is one of the techniques that are widely used for researches into intercalated graphite (Estrade-Szwarckopf 1985). Here, the major part of experimental results has been achieved for graphite intercalated with alkali metals since nuclei of isotopes Li, Ru, and Cs are known to have a magnetic moment differing from zero, which allows one to make a record of them in NMR spectra. In the case of graphite intercalated with potassium, it proved possible to record well-resolved spectra for samples with various concentrations of... 

II In that same period another type of highly reactive metal was introduced in synthetic organic chemistry graphite intercalation compounds Mg/Cg, prepared by reduction of a metal halide by potassium graphitide, K/Cg [57]. 

K. Kahicki and A.W. Morawski [4-7] studied the K-graphite-Fe catalysts derived from FeCl,-graphite intercalation compounds and frirther activation with vapour of metalUc potassium. The high activity of K-graphite-Fe catalysts at pressure of 10 MPa we attributed to presence of K-C-Fe sites where 2s electron is taken by graphite Jt-electron system and is transported also towards iron. Such "electronegatively enriched" graphite framework simultaneously plays a role as an "electronic" and "structural" promoter of iron. 

---