Patent · US Expired

Phthalic anhydride reaction system

US4261899A · kind A · utility

6Cited by
2References
7Claims
0Family size

Assignee

Inventor

Key dates

Filing dateApr 28, 1980
Grant dateApr 14, 1981
Priority date
Expiry dateApr 28, 2000

Classification

  • Technology area (CPC B)Performing Operations; Transporting
  • CPC primaryB01J2219/1946
  • WIPO fieldChemical engineering
  • WIPO sectorChemistry

Abstract

In a process for preparing phthalic anhydride, o-xylene is oxidized with air in a dilute phase transported bed reactor. The reaction is initiated with an o-xylene concentration above the upper flammability limit. Air is injected to a plurality of points along the reactor so as to prevent the oxygen concentration in the reactor from falling too low to maintain catalyst activity, while, at the same time, staying outside of the flammability envelope of the organic-oxygen mixtures. The process permits use of overall o-xylene/oxygen ratios which are substantially higher than were heretofore possible because of safety considerations, thereby minimizing the quantity of inert gases in the system, which reduces the size the complexity of the product recovery system.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.