Ethyl Acetate 99.5%: Water and Acidity Limits Explained

The assay figure on a 99.5% certificate rarely moves from lot to lot. What actually changes is water and acidity, and those two numbers decide whether the grade behaves on a coating or ink line.

Water beyond about 0.10% shows up first as blushing on clear coats and as slow through-dry on humid days. Over time it also feeds corrosion inside drums and IBCs, which is why the lid and the headspace matter as much as the liquid.

Gloved hand holding a vial of clear sample in front of molecular graphics — Karl Fischer titration remains the reference method for water in ethyl acetate.

Acidity, expressed as acetic acid, attacks metal substrates and neutralises amine curatives. A batch that reads high shows tacky films and short pot life long before anything else fails.

On arrival, run three checks before the drum is opened for production: Karl Fischer water, acid value and colour. Ten minutes of bench time settles most grade disputes before they reach the claim stage.