Carbon molecular sieve

Summary

Porous carbon black may be produced by thermal degradation of polymer like polyvinylidene chlorid under conditions, given in the literature. If the degradation reaction is optimized and followed by some additional treatment a carbon black is produced that has the properties of a molecular sieve with an inert surface which is extremely non polar as shown by the negativeRohrschneider constants. This carbon molecular sieve has been used successfully in gas, column, and thin layer chromatography. Retention properties are given for type B carbon molecular sieve which include high retention for CH₂ group, so that water is eluted before methane. Type B is particularly useful for inorganic gas analysis and analysis of traces of some polar compounds with less than 6 C-atoms per molecule. It has a maximum useful temperature of 1400°C. Temperature programmed analysis and automatic ultra trace analysis with the reversion gas chromatography technique is useful due to the non measurable low vapour pressure of the type B carbon molecular sieve.