Issued Patents All Time
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5225574 | Preparation of phthalic anhydride from o-xylene | Heinrich Aichinger, Wilhelm Ruppel, Karl-Heinz Boehning, Walter Scheidmeir, Johannes E. Schmidt +1 more | 1993-07-06 |
| 4961827 | Obtaining very pure maleic anhydride from crude maleic anhydride | Dieter Zimmerling, Johannes E. Schmidt, Karl Fischer, Friedrich Sauer | 1990-10-09 |
| 4921977 | Obtaining maleic anhydride not prone to discolor | Gerhard Michl, Johannes E. Schmidt | 1990-05-01 |