New cation exchanger prepd. from pitch - has controlled sulphonic and carboxylic acid gp. contents, used as catalyst or soil conditioner

(A) Cation exchangers, which are produced from pitch and which have controlled sulphonic and carboxylic acid gp. contents and controlled porosity, are new. (B) Prodn. of the cation exchangers comprises (a) sulphonating heat treated pitch with conc. sulphuric acid or oleum; (b) oxidising with aq. hydrogen peroxide soln.; and (c) opt. hydrothermally treating in an autoclave. USE/ADVANTAGE - The cation exchangers are used as catalysts in chemical conversion processes (e.g. dehydrogenation and alkylation processes), as soil improvers (e.g. to increase colloid contents, increase water retention capacity, prevent soil erosion, provide pH buffering and heat retention, supply trace elements and act as a mulch) and for heavy metal immobilisation in contaminated soils and waste heaps. The cation exchangers are stable at up to 200 deg.C and, if required, porous, have a high content of hydrophilic gps. with different but controlled acid strengths and are inexpensive to produce