Porous carbons

Abstract

A porous resin which can be carbonised to a mesoporous carbon can be made by cross-linking a phenolformaldehyde pre-polymer in the presence of a pore former;, preferably ethylene glycol in an amount of at least 120 parts by weigh of ethylene glycol per 100 parts resin and carbonising the resin formed. The resin can be formed in situ by condensing a phenol with/without modifying agents with cross-linking agent by pouring the partially cross-linked resin into hot oil mesoporous resin beads are obtained which can be carbonised to mesoporous carbon beads.

1 . A method for forming porous resin structure which method comprises condensing a nucleophilic component with an electrophilic cross linking agent in the presence of a pore former.  
     
     
         2 . A method for forming porous resin structure as claimed in  claim 1  in which the nucleophilic component is a phenolic compound or a phenol condensation pre-polymer.  
     
     
         3 . A method as claimed in  claim 2  in which the phenol condensation pre-polymer is a Novolac resin, as herein defined.  
     
     
         4 . A method as claimed in  claim 2  or  3  in which the phenolic compound is a phenol, hydroquinone, or resorcinol.  
     
     
         5 . A method as claimed in any one of the preceding claims in which the pore former is a diol, a diol-ether, a cyclic ester, a substituted cyclic or linear amide or an aminoalcohol.  
     
     
         6 . A method as claimed in  claim 5  in which the pore former is ethylene glycol, 1,4 butylene glycol, diethylene glycol, triethylene glycol, gamma-butyrolactone, propylene carbonate, dimethylformamide, N-methyl-2-pyrrolidinone or monoethanolamine.  
     
     
         7 . A method as claimed in any one of the preceding claims in which there is at least 120 parts pore former per 100 parts of the polymer components by weight.  
     
     
         8 . A method as claimed in any one of the preceding claims which is carried out in solution and the pore former is also the solvent.  
     
     
         9 . A method as claimed in  claim 8  in which the solvent comprises a mixture of a diol with water.  
     
     
         10 . A method as claimed in  claim 8  in which the solvent comprises a binary or tertary or more complex mixture of pore formers from  claim 6  and water.  
     
     
         11 . A method as claimed in any one of  claims 1  to  10  in which the cross-linking agent is formaldehyde, furfural or hexamethylenetetramine.  
     
     
         12 . A method as claimed in any one of the preceding claims in which the pore former is removed by washing after the formation of the resin.  
     
     
         13 . A method as claimed in any one of  claims 1  to  12  in which a solution, obtained by dissolving a Novolac pre-polymer together with one or more of modifying reagents, cross-linking agents and catalysts, in the pore former as a solvent, and heating the solution to bring about a cross-linking reaction, resulting in a solid resin.  
     
     
         14 . A method as claimed in  claim 13  in which a solid porous polycondensation resin is produced by heating the with an acid or basic catalyst.  
     
     
         15 . A method as claimed in any one of claims  13  or  14  in which the modifying reagent is urea, aniline or other aromatic amine or melamine or other heteroaromatic amine.  
     
     
         16 . A method as claimed in  claim 13  to  15  in which the porous resin is produced in blocks and then comminuted and carbonised to obtain a particulate carbon.  
     
     
         17 . A method as claimed in any one of 1 to 11 in which the reaction solution is heated until a limited degree of cross-linking has occurred to produce a partially cross-linked liquid resin solution.  
     
     
         18 . A method as claimed in  claim 17  in which the mixture is heated until a limited degree of cross linking has occurred and the partially cross linked liquid is poured into an immiscible liquid containing a dispersing agent and the mixture stirred until the partially cross linked polymer is formed into beads which are removed from the immiscible liquid to form resin beads.  
     
     
         19 . A method as claimed in  claim 17  or  18  in which the immiscible liquid is an oil.  
     
     
         20 . A method as claimed in  claim 18  or  19  in which a water soluble, but hardly soluble in the dispersing oil pore former is used for meso/macroporous resin production.  
     
     
         21 . A method as claimed in  claim 18 ,  19  or  20  in which the particle size of the mesoporous resin beads formed is between 5 and 2000 microns.  
     
     
         22 . A method as claimed in any one of the preceding claims in which a dispersion of a heteroatom, is incorporated in the porous resin structure.  
     
     
         23 . A method as claimed in  claim 22  in which the heteroatom is a metal and is incorporated in the porous resin structure by adding a solution of a salt to the pore former prior to cross-linking the resin  
     
     
         24 . A method as claimed in  claim 22  in which the heteroatom is a non metal and is incorporated in the porous resin structure by adding an organic precursor containing the heteroatom to the pore former prior to cross-linking the resin  
     
     
         25 . A method as claimed in  claim 22  in which the heteroatom is a non metal and is incorporated in the porous resin structure by adding an inorganic precursor containing the heteroatom to the pore former prior to cross-linking the resin.  
     
     
         26 . A method as claimed in any one of  claims 1  to  25  in which the porous resin is carbonised to produce a porous carbon.  
     
     
         27 . A method as claimed in  claim 26  in which carbonisation is performed at temperatures up to 800° C. and in a flow of inert gas.  
     
     
         28 . A method as claimed in  claim 27  in which an inert gas is carbon dioxide, or nitrogen, or argon.  
     
     
         29 . A method as claimed in  claims 26  to  28  in which the resulting granulated carbon consists of particles of irregular form with the size ranging from 2 microns to 2000 microns.  
     
     
         30 . A method as claimed in  claim 26  to  28  in which the resulting granulated carbon consists of spherical particles with the size ranging from 2 to 1600 microns.  
     
     
         31 . A method as claimed in  claim 29  or  30  in which the porous carbon has a mean pore size of between 2 and 50 nm (mesopores) or bigger than that (macropores) and there are present micropores with a mean pore size between 0.6 and 2 nm.  
     
     
         32 . A method as claimed in any one of  claims 26  to  31  in which the porous carbon is activated by heating in carbon dioxide or steam.  
     
     
         33 . A method as claimed in any one of  claims 26  to  31  in which porous carbon is activated by heating in air above 400° C.  
     
     
         34 . A porous carbon made by the method of any one of  claims 26  to  33 .  
     
     
         35 . Mesoporous phenolic resins beads made by the method of any one of  claims 1  to  24 .  
     
     
         36 . Phenolic resins beads with diameters from 2 microns to 2000 microns with a pore size of mean diameter from 5 nm to 50 nm (mesopores) and above 50 nm (macropores).  
     
     
         37 . Porous carbon spheres of diameter 2 to 1600 microns with a pore size of mean diameter from 2 nm to 50 nm (mesopores) and above 50 nm (macropores).  
     
     
         38 . Porous carbon spheres of diameter 2 to 1600 microns in which there is a mixture of pore sizes comprising mesopores of mean diameter from 2 nm to 50 m or above 50 nm (macropores) and micropores of mean diameter 0.6 to 2 nm.  
     
     
         39 . Porous carbon spheres as claimed in  claim 37  or  38  in which the BET surface area is from 250 to 800 m 2 /g.