PRODUCTION OF CARBON MOLECULAR SIEVE

摘要

PROBLEM TO BE SOLVED: To produce a carbon molecular sieve only through calcination without a special material and/or a complicated treatment, by carbonizing an aromatic polyimide resin. SOLUTION: The aromatic polyimide resin as the material for this molecular sieve is preferably an aromatic polyimide resin in which one of an aromatic carboxylic acid or an aromatic diamine contains >=1 wt.% of an aliphatic carbon based on the total numbers of carbons. Any apparatuses capable of calcination in an inert atmosphere as removing generated gases are useful as the apparatus for calcination (carbonization) of the material. It is preferable that the increasing speed of the calcination temperature is <=10 deg.C/min. and the calcination temperature is >=800 deg.C. The thus produced molecular sieve must have the maximum absorption volume ratio of carbon dioxide to methane gas of >=3 and the equilibrium absorption volume ratio of carbon dioxide to methane gas at 0 deg.C under the atmospheric pressure of >=4 so as to obtain the pore diameter and its distribution both suitable for separation of carbon dioxide and methane gas.