Issued Patents 1989
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4873026 | Process for the preparation of 1-aminonaphthalene-2,4,7-trisulphonic acid and 1-aminonaphthalene-7-sulphonic acid | Heinz U. Blank, Gerhard Marzolph, Willi Streicher | 1989-10-10 |
| 4859372 | Process for the sulphonation of aromatic compounds with sulphur trioxide | Heinz U. Blnak, Wilfried Kohler, Nikolaus Muller, Peter Schnegg | 1989-08-22 |
| 4836959 | Process for the preparation of 1-aminonaphthalene-2,4,7-trisulphonic acid and 1-aminonaphthalene-7-sulphonic acid | Willi Streicher, Gerhard Marzolph, Heinz U. Blank | 1989-06-06 |