Accession Number:

ADA459770

Title:

Probing the Role of Promoters in Zinc Reduction of Nitrobenzene: Continuous Production of Hydroxylaminobenzene [PREPRINT]

Descriptive Note:

Journal article

Corporate Author:

AIR FORCE RESEARCH LAB TYNDALL AFB FL MATERIALS AND MANUFACTURING DIRECTORATE

Report Date:

2006-10-30

Pagination or Media Count:

24.0

Abstract:

Production of hydroxylaminobenzene HAB via zinc reduction of nitrobenzene NB is an established batch process based on aqueous electrolytic reactions involving an electrolyte as the promoter. This experimental study explored continuous production of HAB that is needed as an intermediate in a novel zincbiocatalyst processing train to obtain aminophenols. Experiments were conducted suing a Zn packed bed to probe the role of promoters under continuous-flow conditions at a temperature of 60 deg. C and promoterNB molar ratios of 0.75, 1.15 and 1.5. In addition to the conventional NC4Cl, ammonium formate and acetate were used as promoters. The best HAB yield was 95, as compared to the batch yield of 68. The formation of oxidized zinc species caused the packed bed to build back pressure, which appeared to enhance the selectivity of HABaniline. In situ voltammetric measurements provided evidence of the formation of NB and ammoniumzinc complexes, based on which reaction pathways were proposed. These findings can be used to further improve performance of continuous-flow reactors for HAB production.

Subject Categories:

  • Industrial Chemistry and Chemical Processing
  • Physical Chemistry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE