(618k) Techno-Economic Optimization of a Non-Phosgene Polycarbonate Process

K.M. Bentaher, T.N. Rogers^(*)

Michigan Technological University,Department of Chemical Engineering

1400 Townsend Drive, Houghton, MI 49931-1295

^(*)Corresponding Author

Abstract

Polycarbonate is an important polymer and one of the fastest growing engineering thermoplastics. It is widely employed in different applications, including automobiles, electric and electronic appliances, CDs and DVDs, and mobile phones. The annual growth rate of the global polycarbonate demand is expected to exceed 5% in the period 2011-2016. The global demand for polycarbonate is likely to exceed 6 million tons by 2020, while the production of polycarbonates is expected to reach about 5 million tons by 2020. The reasons for the wide use and high demand growth rate for polycarbonate are its excellent properties, which include outstanding impact resistance, good transparency, high heat resistance, and dimensional stability. Commercially, polycarbonate is produced in four grades, disk grade, low viscosity grade with high melt index (MI), medium viscosity grade with medium MI, and High Viscosity Grade with low MI.

Until recently, the vast majority of polycarbonates has been manufactured by the phosgene process. This process uses carbon monoxide and chlorine as raw materials to produce phosgene, which is highly toxic and its use is highly restricted as a chemical weapon. The phosgene process suffers from a number of environmental and economic drawbacks due to the use of phosgene as a monomer, the use methylene chloride in the polymerization step, and the need for a large quantity of water to separate the phosgene and chlorine from the polycarbonate product.

In order to overcome these environmental issues, this research project focuses on the development of phosgene-free polycarbonate manufacturing process. One of the green routes to produce polycarbonate without using phosgene is transforming dimethyl carbonate (DMC) to diphenyl carbonate (DPC), which can be further reacted with Bisphenol-A to produce Polycarbonate.

Alternative processes to produce the intermediates required to produce polycarbonate through a non-phosgene route will be evaluated technically, economically and environmentally to develop a base case for the polycarbonate process. After-tax discounted cash flow analysis will be used to evaluate the economic viability of introducing an optimized base case of the final non-phosgene polycarbonate process at a suitable US location.