| 摘要 |
A solution of a pyrophosphate of a multivalent metal capable of existing in two valence states, particularly iron, which can be used as an activator solution in the polymerization of an organic monomeric material comprising an unsaturated organic compound containing a CH2=C< group while dispersed in an aqueous emulsion in the presence of an oxidant, e.g. as disclosed in Specification 711,836, [Group IV (a)], is prepared by dissolving in water a salt of the multivalent metal under such conditions that it is present at least in part in a lower valence state, a pyrophosphate of a monovalent cation, suitably alkali metal or ammonium, and either (i) adding a different salt of a monovalent cation and an inorganic anion which is a reducing agent and has no adverse effect on the multivalent metal ions, e.g. an alkali metal or ammonium hypophosphate, thiosulphate, sulphite, bisulphite or hyposulphite and heating between 40 and 100 DEG C. for 5-90 minutes, or (ii) heating as above in the absence of free oxygen and then adding said different salt, each salt being added in amount between 0.1 and 10 parts by weight per 100 parts water. There is present in the solution 0.8 to 1.2 atomic weights of multivalent metal for each molecular weight pyrophosphate. A reducing agent, e.g. a reducing sugar, should be present when the multivalent metal is added in its higher valence state, and may be present when the metal is wholly in its lower valence. Iron salts exemplified are ferrous and ferric sulphate, ferrous nitrate. Reference is made also to oxidation catalysts based on manganese, copper vanadium and cobalt.
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