What is used to scrub or clean glassware in chemistry?

1 Answer
Sep 15, 2016

Usually an alcoholic base bath.


The typical cleaning agent is potassium hydroxide in ethyl alcohol or IMS. The potassium hydroxide goes up slowly. Because hydroxide is a very powerful nucleophile, and especially so in alcohol rather than water, hydroxide anion will attack silicone grease. Before placing my dirty glassware in the bath, I would give it a wipe with paper to remove excess grease, and then soak the beast overnight. The cleanish glassware is then removed from the base bath, rinsed under a tap, and then placed in an acid bath to remove any trace of hydroxide residue.

The glassware is then removed from the acid bath, rinsed again with water, and finally rinsed with IMS prior to drying in an oven.

Ethanolic hydroxide works very well; so does potassium hydroxide in isopropyl alcohol when you add a 1L or so of toluene to 10L IPA (this is an expensive base bath, so don't let your supervizor catch you, or you will get a beat down! And you will deserve it!).

You can keep an alcoholic base bath going for a couple of months, before you need to clean it up. It becomes browner and murkier as you recycle glassware, but still retains its cleaning properties.