Carbon Aerogels, Process for Their Preparation and Their Use

Abstract

The invention relates to carbon aerogels with particle sizes less than 1 μm, The carbon aerogels are prepared by (A) reating a mono- and/or polyhydroxybenzene, an aldehyde and a catalyst in a reactor at a reaction temperature T in the range from 75-200° C. at a pressure of 80-2400 kPa, (B) then spraying the reaction mixture from process step (A) into an acid, to drying the resulting product from process step (B) and (D) carbonizing it. The carbon aerogels according to the invention can be used as filler, reinforcing filler, UV stabilizer, electrode material, sound absorbents, thermal insulating material, catalyst, catalyst support, conductivity additive, absorbent for as and/or liquid preparation or pigment.

1 - 10 . (canceled) 
     
     
         11 . A carbon aerogel, comprising particles with a mean particle size of less than 1 μm. 
     
     
         12 . The carbon aerogel of  claim 11 , wherein said carbon aerogel has a carbon content of 95-100% by weight. 
     
     
         13 . The carbon aerogel of  claim 12 , wherein the density of said carbon aerogel is 0.005-2.0 g/cm 3 . 
     
     
         14 . The carbon aerogel of  claim 13 , comprising particles with a mean particle size of between 0.05 and 1 μm as determined by laser diffraction according to International Organization for Standardization (ISO) procedure 13320-1 (1999). 
     
     
         15 . The carbon aerogel of  claim 13 , comprising particles with a mean particle size of between 0.5 and 0.95 μm as determined by laser diffraction according to ISO procedure 13320-1 (1999). 
     
     
         16 . The carbon aerogel of  claim 13 , wherein the density of said carbon aerogel is 0.15-1.5 g/cm 3 . 
     
     
         17 . The carbon aerogel of  claim 13 , wherein the density of said carbon aerogel is 0.35-1.3 g/cm 3 . 
     
     
         18 . A process for producing the carbon aerogel of  claim 11 , comprising:
 a) reacting a mono- and/or polyhydroxybenzene and an aldehyde in the presence of a catalyst, wherein the reaction is carried out at a temperature in the range of 75-200° C. and at a pressure of 80−2400 kPa;   (b) spraying the reaction mixture produced in step a) into an acid;   (c) drying the product produced in step (b); and   (d) carbonizing the dried product produced in step c).   
     
     
         19 . The process of  claim 18 , wherein said mono- and/or polyhydroxybenzene is selected from the group consisting of: phenol, catechol, resorcinol, phloroglucinol, hydroquinone and mixtures thereof. 
     
     
         20 . The process of  claim 19 , wherein said aldehyde is selected from the group consisting of: formaldehyde, glyoxal, glutaraldehyde, furfural and mixtures thereof. 
     
     
         21 . The process of  claim 18 , wherein said catalyst is an alkali metal hydroxide or alkaline earth metal hydroxide. 
     
     
         22 . The process of  claim 18 , wherein said catalyst is selected from the group consisting of: NaOH, KOH, Na 2 CO 3 , Li 2 CO 3 , K 2 CO 3 , and NH 3 . 
     
     
         23 . The process of  claim 22 , wherein the concentration of mono- and/or polyhydroxybenzene and aldehyde in the reaction mixture is 10-60% by weight, and
 a) said mono- and/or polyhydroxybenzene is selected from the group consisting of: phenol, catechol, resorcinol, phloroglucinol, hydroquinone and mixtures thereof; and   b) said aldehyde is selected from the group consisting of: formaldehyde, glyoxal, glutaraldehyde, furfural and mixtures thereof.   
     
     
         24 . The process of  claim 23 , wherein the concentration of mono- and/or polyhydroxybenzene and aldehyde in the reaction mixture is 20-40% by weight. 
     
     
         25 . The process of  claim 23 , wherein the molar ratio of mono- and/or polyhydroxybenzene to aldehyde is 1:1 to 1:4. 
     
     
         26 . The process of  claim 25 , wherein said acid is selected from the group consisting of hydrochloric acid, nitric acid, phosphoric acid, sulphuric acid, acetic acid, formic acid and oxalic acid. 
     
     
         27 . The process of  claim 26 , wherein the reaction of step a) is performed in the presence of a pore former selected from the group consisting of: ethylene glycol, polyethylene glycol, butylene glycol, diethylene glycol, triethylene glycol, gamma-butyrolactone, propylene carbonate, dimethylformamide, monoethanolamine, N-methyl-2-pyrrolidinone, and mixtures of thereof. 
     
     
         28 . A product comprising the carbon aerogel of claim  1 , wherein said product is selected from the group consisting of: a rubber, plastic, plastic dispersion, adhesive, printing ink toner, coatin, battery, fuel cell, ceramic, dye, paper, bitumen, and concrete. 
     
     
         29 . The product of  claim 28 , wherein said product is an inkjet ink. 
     
     
         30 . The product of  claim 28 , wherein said product is a rubber or plastic.