A Study On The Aqueous Formulations Of 1, 3-dibromo-5, 5-dimethylhydantoin

N,N-dibromo-5,5-dimethylhydantoin (DBDMH) is a highly efficient broad-spectrum sanitizers. However, currently it can only be used and stored in the form of solid formulations due to its lower solubility in water. In some circumstances liquid formulations may be more convenient. On this background the possibility of preparing aqueous formulations of DBDMH is investigated in this paper.The results show that DBDMH is almost insoluble in the typical non-polar solvents. DBDMH therefore is difficult to be entrained into an aqueous formulations in the form of emulsions or micro-emulsions. The solubility of DBDMH is relatively large in solvents containing oxygen and nitrogen, but the DBDMH is either unstable in these solutions or has a solubility less than expectation. It is found that DBDMH has a good solubility and a good stability in binary mixtures of acetonitrile and water, especially in the mixture with azeotropic composition. However, the low water content in the formulation (less than 30 percent ) and the toxicity of acetonitrile prevent this formulation from application. It is also found that the solubility of DBDMH in water can be greatly increased by adding urea. But to keep the DBDMH stable in the formulation the formulated products have to be stored below 10℃, which is not practical. In addition nothing else including surfactants and vesicles they formed has been found to have an expected solubilization power to the DBDMH in aqueous media.Research indicates that sodium dodecyl sulfate (SDS) and didodecyl dimethyl ammonium bromide (D1222) can adsorb at the DBDMH/water interface and D1222 shows an adsorption much higher than SDS. By means of wet milling, DBDMH can be well dispersed in water and SDS or D1222 solutions. In the presence of neutral buffer and thickener, stable suspension of DBDMH in above liquid media can be obtained in which the effective bromide content can be as high as 10%, which show no significant decrease during long time storage. Once diluted, the nano to micro particles of DBDMH suspended dissolves very quickly in water. The suspension is therefore a good form of the aqueous formulations of DBDMH at the moments.