Bordeaux mixture and related compounds as emulsifiers

Summary

Bordeaux mixture precipitates and related materials have been examined as emulsifying agents. It is found that Bordeaux mixture is quite an efficient emulsifier. The emulsions produced are in general coarse but stable like hydroxide stabilized emulsions. The emulsion obtained with nickel Bordeaux is best of all and possesses high stability comparable with the stabilities of emulsions stabilized by basic sulphate of nickel or its hydroxide. On the other hand zinc Bordeaux could not emulsify the oil properly and formed quasiemulsions. Where barium hydroxide and strontium hydroxide have been used as precipitants, the range of the stabilities of emulsions obtained is the same as that of copper hydroxide stabilized emulsions because in these cases the precipitates formed are really hydrated copper oxide. An optimum concentration is necessary to produce effective compounds. Higher concentrations either of the metal or the alkali are detrimental both to the stability and insecticidal capability of the emulsions. Low content oil emulsions are more stable than those, where concentration of the oil is higher, and they are more convenient for practical purposes. Drying of the precipitates which effects its adhesiveness, destroys its emulsifying efficiency. Hence freshly precipitated mixtures are to be preferred.