Hard carbons production

The stereochemistry of the Pd-catalyzed allylation of nucleophiles has been studied extensively[5,l8-20]. In the first step, 7r-allylpalladium complex formation by the attack of Pd(0) on an allylic part proceeds by inversion (anti attack). Then subsequent reaction of soft carbon nucleophiles, N- and 0-nucleophiles proceeds by inversion to give 1. Thus overall retention is observed. On the other hand, the reaction of hard carbon nucleophiles of organometallic compounds proceeds via transmetallation, which affords 2 by retention, and reductive elimination affords the final product 3. Thus the overall inversion is observed in this case[21,22]. 

In addition to surface area, pore size distribution, and surface chemistry, other important properties of commercial activated carbon products include pore volume, particle size distribution, apparent or bulk density, particle density, abrasion resistance, hardness, and ash content. The range of these and other properties is illustrated in Table 1 together with specific values for selected commercial grades of powdered, granular, and shaped activated carbon products used in Hquid- or gas-phase appHcations (19). 

Sony Energytec uses a disordered hard carbon of the type described in region 3 of Fig. 2. These carbons have been produced by a number of Japanese manufacturers including Kureha [41] and Mitsubishi Gas [40], Our recent work [44], and other work in the patent literature shows how such carbons can be produced from natural precursors like sugar and wood. This suggests that it should ultimately be possible to prepare such carbons very cheaply. The specific capacity of region-3 carbons which are in commercial production are around 500 mAh/g. 

Carbonized sugar derivatives are used as solid acid catalysts for the production of biodiesel fuel,349 and carbonized sucrose treated with ethylene and then pyro-lyzed provides materials used as hard-carbon anodes for lithium-ion batteries.439... 

The reactions of type II proceed by transmetallation of the complex 5. The transmetallation of 5 with hard carbon nucleophiles M R (M = main group metals) such as Grignard reagents and metal hydrides MH generates 8. Subsequent reductive elimination gives rise to an allene derivative as the final product. Coupling reactions of terminal alkynes in the presence of Cul belong to Type II. 

Some examples of commercial products are MPG and ICG by Mitsubishi Chemical Co., GDA by Mitsui Mining Co., OMAC by Osaka Gas Chemical Co., 818 by BTR Energy Materials Co., NG-7 by Kansai Thermochemical Co., and DAG by Sodiff.656 Hard carbon coated cokes and soft carbon coated hard carbons are other carbons with core-shell structure reported in the literature.610-657... 

Active carbon or charcoal is an important modification of carbon in catalysis. It consists of carbonized biopolymer material which is activated in a second step. This procedure creates a high specific surface area by oxidative generation of micropores of very variable size and shape distribution. A more controlled activation is achieved by the addition of phosphoric acid or zinc chloride to the raw product. The additive is incorporated during carbonization into the hard carbon and is subsequently removed by leaching creating the empty voids in a more narrow pore size sistribution as achievable by oxidation. Other activation strategies... 

Biomass provides lower yield of activated carbon production versus hard coal, therefore special end product applications need to be developed in order to compensate specific production cost efficiency loss at similar investment... 

The second equivalent of calcium hydroxide is necessary to remove magnesium temporary hardness because the magnesium carbonate product obtained using one equivalent of calcium hydroxide is still somewhat soluble. 

The polymer/zeolite host-guest precursor for preparation of porous carbon can also be obtained through direct contact of monomers in a carrier gas with zeolite molecular sieves followed by polymerization. For example, propylene can enter into zeolite Y under the carriage of N2 and polymerize to form polypropylene. After pyrolysis, the polypropylene undergoes carbonization, and the host zeolite framework of the carbonization product can be removed by dissolution in acids, leaving carbon material with characteristic pores.[93] However, the pore-size distribution of the porous carbons obtained through this approach is not uniform, and hence they are hardly used as molecular sieves for sieving small molecules. 

---