Allied Chemical Corporation

Alliedsignal Inc.

Allied Corporation

Laszlo J Balint

Lamberto Crescentini

William B Fisher

Stanley D Lazarus

Beryl A Boggs

Edward J Buyalos

Leonard Evans James

Muhammad S Sahli

Julius Greenburg

Patrick William Ager

In a process for the production of hydroxylamine disulfonate diammonium salt (DS) comprising feeding an aqueous ammoniuum nitrite solution, SO.sub.2 gas and trim ammonia to a packed column to create a reaction mixture to produce DS; the improvement comprising controlling said process by measuring the pH of the DS product solution stream, comparing said pH with a pre-selected pH value, and adjusting for deviation of pH by adjusting the feed of nitrite solution and measuring the concentration of unreacted nitrite in the DS product solution stream, comparing said concentration with a pre-selected concentration value, and adjusting for deviation of said concentration by adjusting the feed of trim ammonia.

Disulfonate process control

In the production of hydroxylamine disulfonate diammonium salt (DS) comprising reacting ammonium nitrite with ammonium bisulfite and sulfur dioxide in an absorption reactor whereby emission gases comprising NO.sub.x, particularly NO, are released as a result of side reactions, the method of treating said emission gases to reduce the concentration of NO comprises adding NO.sub.2 to the emission gases and contacting the mixture of NO.sub.2 and emission gases with an aqueous alkali solution sufficiently to form nitrite and nitrate ions in said alkali solution.

Abatement of NO.sub.x from hydroxylamine disulfonate process

Method and improved apparatus for recovering a volatile organic material, such as caprolactam, from a liquid mixture of organic and inorganic materials are disclosed. The method features the step of mixing the liquid mixture with superheated steam for 0.005 to 1.0 second to vaporize a large portion of the volatile organic material without degrading the organic materials. The steam and vaporized organic materials are then separated from the liquid mixture remaining, followed by separation of the vaporized organic material from the steam. The vaporized organic material subsequently is condensed. The improved apparatus features means for introducing superheated steam into a vaporizer feed pipe, as well as means for mixing the superheated steam with the liquid mixture in the pipe for 0.005 to 1.0 second so that a large portion of the volatile organic material is vaporized and feeds with the steam and remaining liquid mixture into the vaporizer for separation.

Method for recovering caprolactam

Ammonium nitrite is commercially produced by contacting a gaseous stream containing nitric oxide, nitrogen dioxide, nitrogen and oxygen with an aqueous solution containing a basically reacting ammonium compound in an absorption system. However, at normal production rates, serious problems have been encountered because of relatively low yield of ammonium nitrite and the emission of unreacted nitric oxide which causes pollution of the atmosphere. It has now been found that in situ generation of nitrogen dioxide in the absorption system by operating the absorption system under slight pressure greatly improves ammonium nitrite yield, reduces nitrogen oxide emission, reduces loss of ammonia as nitrogen and minimizes mist formation in the vent gas. Moreover, with respect to environmental pollution, we have discovered that a synergistic improvement results from an interaction effect involving use of said sight pressure in combination with late addition of controlled supplemental quantities of nitrogen dioxide to the nitrogen oxide gas while said gas is being absorbed in the absorption system.

Process for the synthesis of ammonium nitrite

In a process for the preparation of high molecular weight linear polyesters of terephthalic acid which comprises partially esterifying terephthalic acid with an alkylene glycol under direct esterification conditions and then further esterifying and polycondensing the partially esterified product, the molecular weight distribution of the polyester is narrowed by correlating the carboxyl conversion with the reacted glycol to terephthalic acid mol ratio in various steps of a multistep process.

Process for preparing polyesters

In an essentially horizontal totally enclosed cylindrical wiped-wall polymer reactor having an essentially horizontal polymer flow, a pool of polymer in its lower portion, and driven wheels to create high surface area in the polymer to facilitate evaporation of volatiles from the polymer, the improvement comprising a freewheeling drag wheel driven by the driven wheels, with a wiping means mounted on the driven wheels and actuated by the drag wheel to wipe the entire internal circumference of the cylindrical reactor. The drag wheel generates a force to urge the wiping means outward against the internal circumference of the reactor. The force is generated by the drag of the pool of polymer on the drag wheel. This keeps the wall of the reactor wiped with a fresh film of polymer. The process and apparatus is particularly adaptable to driven wheels and drag wheels eccentrically mounted in the reactor.

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Chester, VA, United States of America

Laszlo J Balint