Published December 2002
Acetaminophen (APAP) is an analgesic used in pain and cold medications. Like aspirin, it is used both alone and in many combinations with other drugs including codeine or antihistamines. APAP dominates the global market for bulk analgesics. The APAP segment of the bulk analgesics market is estimated to be between 75,000 and 80,000 metric tons per year with a global market value of over $350 million.
Mallinckrodt is the world's largest manufacturer of APAP, with production about twice that of its nearest competitor. The company's largest APAP facility is a 30,000 t/yr APAP production unit in Raleigh, NC. Nitrobenzene is used as the precursor at the Raleigh plant. Nitrobenzene is hydrogenated to form p-aminophenol (PAP), which is acetylated to APAP. The first process for the preparation of PAP by catalytic hydrogenation was patented over 60 years ago. Mallinckrodt has patented a number of improvements since that time.
Production cost has long been a critical factor for success in the APAP business, because it is a price-intensive, commodity type of market. During the past several years APAP market prices have fallen worldwide due to competition from Chinese and Indian companies. Although the current U.S. list price is over $8 per kg, the estimated world market price is much lower. Mallinckrodt has undertaken a variety of process improvements to remain competitive. The focus of this review is the manufacture of APAP from nitrobenzene using the most recently patented process technology. We examine the economics and technical issues for a new grass-roots 66 million lb/yr (30,000 t/yr) APAP facility based on the nitrobenzene route.