Does Pyrocatechin go bad?

[ParkerSmithPhoto]

A friend has a bottle of unopened Pyrocatechin from 1988, and it is "about Zone VII" in his words. Does this stuff go bad?

 

[Gerald C Koch]

If you are referring to the pure solid then no. It has the same stability as hydroquinone. Keep it in a well sealed jar, preferably glass, protected from light and moisture. Unlike hydroquinone it does have a measureable vapor pressure at room temperature. Therefore the jar must be well sealed to prevent loss. The rate is quite small but noticeable over a long period.