Abstract: The invention is a process to regenerate monolith catalytic reactors employed in the liquid phase hydrogenation reactions, particularly those kinds of reactions involving nitroaromatic compounds. The catalytic metals in the monolith catalytic reactor are deactivated by carbonaceous and deactivating byproducts and must be regenerated to extend the catalyst service life and reduce costs. The regeneration process involves two steps: initially passing an oxidizing gaseous mixture through the monolith catalytic reactor at an elevated temperature and for a time sufficient to remove carbonaceous and deactivating byproducts; and then passing a reducing gas though the monolith catalytic reactor previously exposed to the oxidizing gas under conditions for reducing the catalytic metal to its reduced state.

Abstract: This invention relates to an improved process for the production of dinitrotoluene wherein one is able to effectively employ a feed sulfuric acid, which is referred to as "weak acid" as the feed sulfuric acid for the nitration facility. The weak acid concentration, as feed, ranges from 86-91%, preferably 87-89% sulfuric acid by weight, to meet the total sulfuric acid requirements for the facility. This is accomplished by utilizing cocurrent processing in a mononitration zone and countercurrent nitration with respect to sulfuric acid in the dinitration zone.