Abstract:
The invention relates to a process for the preparation of mechanically and osmostically stable high capacitive very acidic cation exchangers with a grain size of >/= 0.1 mm by sulphonation of gel-like or porous pearl polymers with sulphuric acid without using inert chlorine-containing swelling agents and/or of co-monomers based on acrylonitril. The invention proposes that such very acidic cation exchangers can be prepared by sulphonation of gel-like and porous pearl polymers, prepared by copolymerisation of styrene and divinyl benzene with a cross-linker proportion of up to 65 % by weight of divinyl benzene with or without inert agent, with a sulphuric acid concentrated at 80-96 % at temperatures of 125-180 DEG C, the reaction period being of up to 20 h. In the new process, very acidic cation exchangers can be prepared without using the inert, chlorine-containing, ecologically-harmful swelling agent, 1,2 dichloroethane, with the same or similar quality features and substance characteristic data as products prepared using conventional processes.
Abstract:
By adding linking wetting agents or water-soluble initiators or tensides during polymerisation or after filtration of the end product and/or by taking technical measures, the grain pile of the very acidic cation exchangers is able to flow freely permanently or temporarily using the following process. By adding to the copolymerisation system, known wetting agents in quantities of up to 0.25 g/l of the aqueous phase or water-soluble initiators in quantities of from 0.05 to 20 g/l of the aqueous phase 20 to 120 minutes after reaching the point of gelification.
Abstract:
The invention relates to a process for the preparation of free-flowing end products of very acidic cation exchangers. The grain pile of end products of the very acidic cation exchangers produced in the process described in the patent application P 195 48 012.0 cannot flow freely. By adding linking wetting agents or water-soluble initiators or tensides during polymerisation or after filtration of the end product and/or by taking technical measures, the grain pile of the very acidic cation exchangers is able to flow freely permanently or temporarily using the following process: (1) by adding to the copolymerisation system, known wetting agents in quantities of up to 0.25 g/l of the aqueous phase or water-soluble initiators in quantities of from 0.05 to 20 g/l of the aqueous phase 20 to 120 minutes after reaching the point of gelification; (2) by treating the very acidic cation exchangers with aqueous solution of surfactants with a content of from 0.1 to 5 g/l in the batch or column process; (3) by 1 to 4 hours of washing of the very acidic cation exchangers with water of at least 60 DEG C, subsequent separation off of the water and drying of the end product using sensible heat.