Preparation of Molecular Sieving Carbon by Carbonization of Phenol-3,5-Dimethylphenol-Formaldehyde Resin
Molecular sieving carbon (MSC) has selective adsorption property dependant on the size and/or the shape of the adsorbate. Several methods to prepare MSC have been reported and the carbonization of an organic material (carbonization process) is one such method. However, it is very difficult to control the carbonization process, because of the multiple complex reactions that occur during the process. Also, the pore structure of the resultant char depends on the carbonization temperature and the raw material used. We synthesized two phenol resins; phenol-formaldehyde resin (PF-resin) and 3.5-dimethylphenol-formaldehyde resin (XF-resin). Theses resins were carbonized at 873-1273K and then the pore structure and the carbon structure were investigated. The carbon crystallite in PF-resin char was located more disorderly compared with that in XF-resin char. And then the PF-resin char had larger pore volume and broader pore size distribution than XF-resin char had. These resin mixture (XPF-resin) were synthesized with different mixing ratio (phenol/3.5-dimethylphenol:1.0-3.0) and these resins were carbonized at 873-1273K. And the influence of the mixing ratio and the carbonization temperature on the pore structure and carbon structure were investigated. The prepared char had the large pore volume and the sharp pore size distribution. And the pore size of XPF-resin char could be modified in the rage of 0.35-0.44nm by changing the mixing ratio. Using XPF-resin (phenol/3.5-dimethylphenol =1.0 and 2.0) char prepared at 1173K, methane could be recovered from methane-carbon dioxide mixture such as bio-gas. And also, XPF-resin (phenol/3.5-dimethylphenol =1.0) char prepared at 973K had molecular sieving property for propane-propylene separation.