In 1952 the phenomena of Blue Ice was observed. P-Chem lab students at the University of Oklahoma were performing thermometric studies on various concentrations of tetrahydrofuran (THF) in water in support of an ONR research project broadly encompassing hydrocarbon-type hydrates.
In the second week of the laboratory, some solutions which had been stored in the students’ desk, turned blue upon freezing in a dry-ice hydrocarbon mixture.
As a research assistant, I was assigned to investigate the phenomena. This behavior was traced to the presence of a small amount (0.1%) hydroquinone present in the THF as a stabilizer. Blue ice appeared only after storage of the solutions at room temperature. Investigation revealed that dilute hydroquinone solutions (the presence of THF was not required) when stored for several days at room temperature or when heated for a short while (about 1 hour at 70-80° C was sufficient), developed a pink color. Only then would the solution turn blue when frozen. The phenomenon is reversible. However, one solution that originally turned blue upon freezing did not after storage for a year. I have not repeated this observation.
Over the years, I have demonstrated this experiment for various people but have never published it. A curious but unsubstantiated observation suggests that tap water rather than distilled water may be preferred. A dilute pale yellow solution of Tetrahydroxy-1,4-quinone did not turn blue upon freezing,
Has anyone else observed this and discovered the reason for the color?