Science Buddies: "Ask an Expert"

Hey guys,
I am working on the early stages of a project about chromic phenomena and their real life appliances.
During my research I discovered Reichhardt's Dye, a really fascinating solvatochromic that sounds promising for my desired projects.
However, I can't find the information I need about the dye and can't test it myself, so I wanted to ask here if anyone can help me.

First Question: which color is Reichhardt's Dye in pure water?
Second Question: If I mix Reichhardt's Dye with Isopropanol the mixture will be blue. What happens when I spoil the solvent over a white piece of plastic and the Isopropanol evaporates? Will it still be blue?

Thank you very much!

Hi alphabeta,

I’m not familiar with Reichardt’s Dye but after a bit of searching I found a material data safety sheet indicating that the dye (a powder) is not soluble in water.

http://www.scbt.com/datasheet-215801-re ... s-dye.html

But the dye is soluble in mixtures of acetone and water. The demonstration described at the following link follows the color changes as water is added to an acetone solution of the dye. The color is orange-red in a mixture of 20% acetone and 80% water.

http://www-chem.ucsd.edu/undergraduate/ ... emo38.html

I think that if you make an isopropanol solution of the dye (blue) and allow the solvent to evaporate, the color of the remaining dye will be the same as the original powder used for the solution. But I was not able to find the color of the dye powder in my searches.

I hope this helps and good luck with your project. Please post again if you have more questions.

A. Norman