Carbon molecular sieve production

Juntgen, H. Knoblauch, K., and Harder, K Carbon molecular sieves Production from coal and application in gas separation, Fuel, 60(9), 832-838 (1981). 

As an example of the selective removal of products, Foley et al. [36] anticipated a selective formation of dimethylamine over a catalyst coated with a carbon molecular sieve layer. Nishiyama et al. [37] demonstrated the concept of the selective removal of products. A silica-alumina catalyst coated with a silicalite membrane was used for disproportionation and alkylation of toluene to produce p-xylene. The product fraction of p-xylene in xylene isomers (para-selectivity) for the silicalite-coated catalyst largely exceeded the equilibrium value of about 22%. 

Molecular sieve dryers, 10 613 Molecular-sieve effects, 16 821 Molecular sieve membranes, 15 813t Molecular sieve products commercial, 16 838-839t manufacturing processes for, 16 831 Molecular sieves, 16 811-853. See also Carbon molecular sieves Zeolite entries... 

By carefully choosing the starting material and the activating process, it has been possible in recent years to generate in carbon a pore system with a narrow span of pore sizes. With a mean pore diameter of perhaps 0.6 nm, such products are known as carbon molecular sieves. 

The development of new porous materials that could be used as adsorbents, catalysts, catalyst supports, molecular sieves, etc. [1], are very well discussed by several authors [2-9], describing interesting properties and characteristics of materials such as MCM-41, MCM-48, M41S, FSM16, lamellar phases, intercalation products, special CMS (carbon molecular sieves), fullerenes, carbon nanotubes, etc. being some of them silica based materials, and carbon based the others. 

Nitrogen production using carbon molecular sieves is the only known commercial process using differences In lntrapartlcle diffusivity, rather than inherent adsorbent selectivity or selective molecular exclusion, as the basis for the separation ... 

FIGURE 11 Sequence of steps in a two-bed pressure swing adsorption system, (a) Skarstrom cycle, (b) modified cycle for production of nitrogen using a carbon molecular sieve adsorbent. 

Nitrogen production via PSA (pressure swing absorption) is based on the principle that nitrogen and oxygen have different absorption rates on carbon molecular sieves (CMS). Some of the nitrogen production processes that use this technology are described in References 1 and 3-6. 

Carbon molecular sieves, or carbogoric sieves are amorphous materials made by pyrolyz-ing coal, coconut shells, pitch, phenol-formaldehyde resin, or other polymers. EKslocations of aromatic microdomains in a glassy matrix give their porosity. Pores are slit-shaped. Pore structure is controlled by the temperature of the pyrolysis. Pore widths range from 3 A to 10 A. Acarbogenic sieve made from polyfurfuryl alcohol and combined with silica-alumina was selective for monomethylamine production from methanol and ammonia [54]. 

S. Sa, H. Silva, J. M. Sousa and A. Mendes, Hydrogen production by methanol steam reforming in a membrane reactor Palladium vs carbon molecular sieve membranes, J. Membr. Sci., 2009, 339, 160-170. 

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