Air Products and Chemicals, Inc.

William Joseph Mazzafro

Stephen Ian Clarke

Richard Van Carr

Michael S Chen

Frederick Carl Wilhelm

Anthony Rocco Cartolano

Keith Allen Welp

Pierre L Brian

Mark Shedric Simpson

Suresh M Vora

Philip N Taylor

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.

Process for regenerating a monolith hydrogenation catalytic reactor

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.

Weak acid process for producing dinitrotoluene

A process for the purification and concentration of sulfuric acid contained with nitric acid by-products and organic components pursuant to the mixed acid nitration of aromatics. The process resides in the integration of a purification system with a concentration system which includes:

Process for purification and concentration of sulfuric acid

This invention relates to an improved process for reducing solute in a vapor stream and, particularly, to the adaption of this process in concentrating solutions in an evaporator wherein the solution is heated to volatilize solvent. The improvement for reducing solute in the vapor stream resides in (a) the utilization of a wire mesh mist eliminator pad having a wire diameter of from 0.001-0.05 inches, an interfacial area from 50-200 ft.sup.2 /ft.sup.3, a void space of about 90-99 percent and a packing thickness of 4-16 inches and (b) spraying a liquid through the mist eliminator pad, the liquid being sprayed uniformly over the surface of the mist eliminator pad at a rate of 0.6-2.5 pounds liquid per pound of vapor to provide a wetting rate of 0.1-0.25 gallons per minute per square foot of mist eliminator surface area. The process has been particularly advantageous in the multistage concentration of corrosive products particularly in the concentration of a 60-70% sulfuric acid solution to about 93 percent.

Process for concentrating sulfuric acid in an evaporator

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Schnecksville, PA, United States of America

William Joseph Mazzafro