The Role of Alpha-Ketols in the Low-Sugar Redox Recipe for Low Temperature Emulsion Copolymerization

Abstract

I t was found.that the induced deconlposition of peroxy co~llpounds c o~~l d lead to faster rates of polymerization or practical rates of polymerization a t lower tcmperat~tres. In Germany polymerization recipes were developed containing a pefosy conlpound in the oil phase, a reducer in the aqueous phase and a metal carrler. 'This idea was transferred to America after the war and became the basis of the present recipes used i n the production of cold rubbers. As reducers the most comn~only used appear to be digested d-glucose or a n excess of ferrous iron but recently the polyamines and other amine conipounds have been found to be quite effective. 'The mixture of anline and sugar was better than either alone. I t has been shown that this mixture will function in the presence of reactive monomers such a s acrylonitrile. The role of such reducers is of considerable interest so t h a t further studies were undertaken. The results obtained may be illustrated by acetoin. .4s the amount of acetoin is increased in the recipe the arnount of ferrous iron required for maximal conversion in a given time 1s decreased. This is because a t higher than the optimal amounts, although the reaction rate is still increasing, the catalyst system is rapidly exhausted so that the reaction dies a t a lower conversion. T h e data can be explained by assuming formation of free radicals by the induced decomposition of the peroxide either by the acetoin, the ferrous iron, or a co~nplex between the iron and acetoin. This free radical then initiates polymerization. T h e acetoin free radical residue can induce the further decon~position of the peroside or possibly can reduce ferric iron to ferrous. Other con~pounds yield similar results. IntroductionSome of the earliest studies of activated polymerization reactions are those of Stewart (49,50,51,52,53) in which redox catalysts con~posed of a polymerization initiator, a heavy metal, and a phosphate or polyphosphate such as pyrophosphate or fructose diphosphate, an organic acid, or a polyhydroxy conlpound such as dextrose. E. I. du Pant de Nemours and Co. patented similar systems (44).The German work developed the desirable combination of an oil soluble peroxy conlpound and a water soluble reducer in combination with a heavy metal carrier to a high degree. These results were summarized by Weidlein (63) who mentioned the system benzoyl peroxide -ferrous fatty acids -sorbosesodium pyrophosphate. Later several publications appeared in Germany (17, 18,19,20,21,31,33) describing their earlier work and several in the United States describing the studies there which were stimulated by the earlier report (63).Wall and Swoboda (62) attempted to formulate the reactions of such a system. Some credence to their postulate could be given when such highly

Relation between the degradation of DDT and the iron redox system in soils

“…The reduction of ferric iron in water-logged soils has been attributed to microbial activity, but Takai and Kamura (1966) have reported evidence of the chemical reduction of iron with reduced organic products that resulted from the anaerobic decomposition of the organic amendment. Other workers in basic organic chemistry research have demonstrated the reduction of ferric iron to ferrous with various types of sugars (Orr and Williams, 1951). In the mechanisms, it was suggested that sugar and ferric iron formed a complex that resulted in the formation of sugar free radicals, which subsequently reduced the remaining ferric iron.…”