GB937359A - Hydrogen peroxide - Google Patents

Abstract

<PICT:0937359/III/1> <PICT:0937359/III/2> An aqueous solution of hydrogen peroxide is produced by reacting peracetic acid and water in contact with a synthetic sulphonic cation exchange resin free from heavy metal ion, and substantially insoluble in and resistant to oxidation by said peracetic acid and water mixture at from 20 DEG to 90 DEG C., distilling the resulting mixture of hydrogen peroxide, acetic acid, peracetic acid and water by vacuum fractional distillation to separate peracetic acid, water and acetic acid from hydrogen peroxide, and recovering a hydrogen peroxide aqueous solution. Examples of resins which may be used are the sulphonated polymers of polyvinyl aryl compounds, e.g. divinyl benzene, and the sulphonated copolymers of such polyvinyl aryl compounds with monovinyl aryl compounds such as styrene. The resin is conditioned before use, for example by washing it with an aqueous solution of 10% HCl, exhausting with 10% NaCl, regenerating with 10% HCl and then washing with de-ionized water. At least 0,2 parts of resin are used for every 100 parts of peracetic acid. In Fig. 1, the peracetic acid-water solution is passed from feed funnel 2, through heating zone 3, to resin bed 1 which may be heated by a hot water jacket, and the treated solution is collected in reservoir 4 and then passed to fractionation column 5 equipped with heating coil or reboiler 6. Peracetic acid and water are removed from the top of column 5, condensed and may be recycled. The residue from column 5, acetic acid, hydrogen peroxide and water, is passed into a second fractionating column 11, the overhead products of acetic acid and water are removed and the residue which is a concentrated aqueous hydrogen peroxide solution is collected in reservoir 14. Columns 5 and 11 are operated under vacuum (below 300 mm. Hg). Water is added to columns 5 and 11, at ports 18 and 19, if the distillation is performed at a vacuum above 50 mm. Hg and the peroxide concentration in the residue reaches 90% or above. In Fig. 2, peracetic acid, acetic acid and water are removed from the top of column 5, condensed by 7, collected in reservoir 20 and then passed into fractionation column 11 where peracetic acid and water are removed from the top, then condensed and may be recycled to the resin bed, while acetic acid is collected in reservoir 14. Concentrated aqueous hydrogen peroxide solution is recovered as residue from column 5 in reservoir 10 and may be used as such or subjected to flash evaporation under vacuum. As before, water may be added to column 5. If desired two or more resin beds may be used if the process is to be continuous.