Production of Acetic Acid from the Monsanto Process

Abstract

Acetic acid is a clear, colourless, corrosive liquid that has a pungent odour and is a dangerous vesicant. It has pungent vinegar like odour. Mostly, acetic acid is manufactured by methanol carbonylation, direct oxidation of n-butane and direct oxidation of ethylene. The total worldwide production of virgin acetic acid is estimated at 5MMTPA (million metric tons per year). Acetic acid is used in the manufacture of a wide range of polymers like PVA (poly vinyl acetate), adhesives etc. It is also used in the manufacture of bleaching agents, pharmaceutical products and agro-chemicals. The Monsanto process is studied in depth for this project. Methanol Carbonylation (Monsanto Process) was initiated in 1960 by BASF. The raw materials used for this process are Carbon Monoxide and Methanol. The optimum conditions for this process are 180°C-220°C temperature, 30-40 atm pressure and Rhodium catalyst with hydrogen iodide as promoter. Due to high selectivity of raw materials, the finals products are of great purity. The Monsanto process is designed and optimized for this project. It is studied in depth and simulated using Aspen Hysys. Research is being done on Lithium based promoters to reduce operating temperatures to under 120℃. In the future, a reactive distillation scheme may be developed to integrate all plant units into one main vessel.