Thymolphthalein

September 19, 2006
Image of Thymolphthalein 3D Image of Thymolphthalein

An alkaline solution of thymolphthalein in alcohol makes a very good disappearing ink. The solution starts out blue, but when it absorbs carbon dioxide from the air, carbonic acid is formed, neutralizing the alkaline solution and causing the blue color to vanish. The color returns when the ink spot is treated with an alkaline solution.

Chemical Abstract Service - a division of ACS

Learn more about this molecule from CAS, the most authoritative and comprehensive source for chemical information.

Molecule of the Week needs your suggestions!

If your favorite molecule is not in our archive, please send us a message. The molecule can be notable for its current or historical importance or for any quirky reason. Thank you!

Stay Ahead of the Chemistry Curve

Learn how ACS can help you stay ahead in the world of chemistry.