Porous carbons

#The present invention relates to improved phenolic resin structures which can be used as ion exchange resins and can be used to prepare porous carbon materials and to a methods for making these.

#Sulphonated phenolic resins were first used as ion exchange resins in the 1930's (Adams et al, J Soc Chem Ind. 54, (1935) 1-GT) and relatively stable cation and anion exchange resins were used extensively for the softening and demineralisation of water. Other phenolic based resins include the weak base anion exchange resins that have been primarily used in food processing applications (Cristal M J, Chem and Ind, 814, (1983) Nov. 7) and chelation resins which can be produced to give remarkable selectivity for the adsorption of metal ions such as cesium (U.S. Pat. No. 4,423,159, 1983 and U.S. Pat. No. 5,441,991, 1995). The ion exchange powders, can be produced by either bulk curing of the resin followed by milling (e.g. WO91/09891) to produce a low porosity powder or by reversed phase condensation (Unitaka Ltd U.S. Pat. No. 4,576,969 1986). One of the limitations of these materials was limited internal porosity and they were rapidly replaced by the highly porous sulphonated styrene divinyl benzene copolymer based ion exchange resins when these became available. However, although the phenolic based resins have largely disappeared, specific applications do still exist in food related industries based on their underlying performance characteristics.

#The phenolic resins can be carbonised to form mesoporous carbons. Mesoporous carbons are used as adsorbents or catalysts supports and can be used in spherical, granular of thin film form. Existing production methods use gas phase and chemical activation routes to produce mesoporous carbons but, activated carbon, as conventionally produced, is normally microporous (<2 nm pore diameter−IUPAC definition) with little or no pore volume in the mesopore (2-50 nm) and macropore (>50 nm) range. For some critical adsorption processes such as evaporative emission control, and when used as a catalyst support, particularly in liquid phase applications, this is a major drawback.

#These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:

#FIG. 1 shows pore former content in the resin composition on the porosity of derived carbonized material with reaction system Phenol-Formaldehyde-Ethylene Glycol-Sulphuric Acid;

#FIG. 2 shows the effect of aniline content in resin composition of the reaction system Phenol-Aniline-Formaldehyde-Ethylene Glycol-Sulphuric Acid on the porosity of derived carbons;

#The nucleophilic component can be for example phenol, a phenolformaldehyde pre-polymer—a Novolac optionally together with a modifying agent.

#The electrophilic component can be for example formaldehyde, hexamine, furfural.

#Preferably the pore former acts as the solvent.