A 4. GAAPHAARO AO77 Maww
April 7, 1970 - E. SMITH ET All 3,505,308 PRODUCTION OF AZODICARBONAMIDES UTILIZING BROMINE Filed Oct. 27, 1966 WATER HYDRAZINE HYDRATE HYDRAZINE AQUEOUS HYDROCHLORIC ACID HYDRAZINE HYDROCHLORIDE AQUEOUS UREA HYDRAZO DLCARBONAMIDE SLURRY AZO DICARBONAMIDE SLURRY (ACID) CAUSTC BROMIN AZO (MAKE-UP) DICARBONAMIDE SLURRY (NEUTRAL) Cl2 AZO AIR (N2) DICARBONAMIDE PRODUCT BROMINE BROMIDE STORAGE LIQUOR AIR (N2) HCl acq. INVENTORS." AAR/C SM)7A/ WOffW A. AAPAGA EA? a 4. GAAPHAARO AO77 MaWW AGEw7 3,505,308 United States Patent Office Patented Apr. 7, 1970 1. 2 U.S. Patent 3,190,873 of 1965 and equivalent Belgian 3,505,308 PRODUCTION OF AZOOCARBONAMIDES Patent 627,533 of 1963 disclose passing chlorine gas UTELIZING BROMINE into a suspension of hydrazodicarbonamide (hydrazo Eric Smith, Madison, John E. Pregler, Wallingford, and formamide) in concentrated HCl, containing a bromide, Gerhard F. Ottmann, Hamden, Conn., assignors to to produce azodicarbonamide (azoformamide) in 93% Olin Mathieson Chemical Corporation yield. Filed Oct. 27, 1966, Ser. No. 589,911 Belgian Patent 631,410 of 1963 discloses passing chlo nt. C. CO7 07/02 rine gas into an aqueous suspension of hydrazodicarbon U.S. C. 260-192 10 Claims amide containing minor proportions of bromine, or a IO bromide, to produce azodicarbonamide in yields of 93 99%. With chlorine alone, yields are 35-38%. ABSTRACT OF THE DESCLOSURE In these processes, the chlorine must be introduced Azodicarbonamide having particle size especially suit slowly, with careful control, to avoid extensive forma able as a blowing agent in plastics and rubber composi tion of by-products by side reactions and over-oxidation tions without the necessity of any grinding or sizing is of the desired product.
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