Synthesis of polycondensation ion exchange resin(II)
2、 Weak acid cation exchange resin
The carboxylic acid type cation exchange resin was first synthesized by condensation polymerization of 3,5-dihydroxybenzoic acid and formaldehyde. The exchange capacity of this resin can reach about 7 meq/g.
Dissolve 20g of 2,4-dihydroxybenzoic acid in alkaline water, add 10g of sodium chloride and 6g of phenol, then place them in ice salt water for cooling, add 44g of formaldehyde dropwise under stirring, and react at 40 ℃ (about 50min) until they become dark red and viscous resin slurry. Finally, it is dispersed in the turbine oil to an appropriate particle size, polymerized at 55 ℃, and dehydrated at 110 ℃ to obtain a dark red spherical macroporous weak acid resin.
Soluble starch, Na2SO4 or NaCl are used as pore forming agents to make salicylic acid and formaldehyde polycondensate. After emulsification, a certain amount of phenol and formaldehyde are added. When the system is polymerized to be viscous, suspension polymerization is continued in turbine oil to obtain weakly acidic resin with similar structure.
The weak acid resin has good adsorption performance for vitamin B2, and is also effective for decolorization of streptomycin sulfate eluate.
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