... Tetrahedron Letters. Volume 37, Issue 4, 22 January 1996, Pages 513–516. Cover image Cover image. Sulfuric acid on silica-gel: an inexpensive catalyst for aromatic nitration. ... in: GA Olah (Ed.), Friedel-Crafts and Related Reactions, vol. 3Interscience, New York (1964) Part 2. ...