1. Field of the Invention
This invention relates to catalysts for chemiluminescent systems. More particularly, this invention relates to catalysts for two component chemiluminescent systems wherein one component is a hydrogen peroxide component and the other component is an oxalate ester-fluorescer component.
2. Description of the Prior Art
Two component chemiluminescent systems which utilizes a reaction mixture of a hydrogen peroxide component and an oxalate ester-fluorescer component to produce light are well known. In such systems a solution of hydrogen peroxide in dimethyl phthalate or a mixture of dimethyl phthalate and t-butyl alcohol and a solution of an oxalate ester such as bis(2,4,5-trichlorocarbobutoxyphenyl) oxlate, and a fluorescer, for example 9,10-diphenyl anthracene, in a solvent such as dibutyl phthalate are mixed and allowed to react whereupon light is produced.
In two component chemiluminescent systems of the type described, a catalyst is generally included as part of the hydrogen peroxide component. Many catalysts have been tried. Of the catalysts tried, sodium salicylate and various tetraalkylamminoum salicylates have been the most widely used.
Sodium salicylate and tetraalkylammonium salicylates are excellent catalysts for chemiluminescent systems of the type described. However, they have certain disadvantages. First, they are not highly soluble in mixtures of dimethyl phthalate and t-butyl alcohol which are the most commonly used solvents for the hydrogen peroxide component. Because of their relatively low solubility, systems which will produce short duration high intensity light cannot be produced. Short duration, high intensity light systems require fairly large concentrations of catalyst. Second, even at relatively low concentrations, sodium salicylate and the tetraalkylammonium salicylates tend to precipitate out of dimethyl phthalate and mixtures of dimethyl phthalate and t-butyl alcohol at low temperatures. This is obviously undesirable when one realizes that chemiluminescent devices may be required to operate at low temperatures.