The purpose of this research is to develop a general strategy for attacking environmental waste problems in industrial processes, that include process design and optimization, application of catalytic and alternative chemistry, reduction in the use of toxic chemicals, recycling, and recovery to eliminate waste at its source. The PIs plan to apply process design techniques, an improved understanding of process chemistry, and newly developed synthetic and catalytic chemistries to improve the energy efficiency and cost effectiveness of the process to produce sulfolane (as an example process), while minimizing waste. The anticipated benefits include: (1) the development of alternative processes, chemistries, and approaches that could be used to attack environmental and energy problems associated with other industrial processes, and (2) the development of models for considering environmental costs in process design and optimization and exposing chemists to the need to consider energy efficiency, by-product production, and waste generation and disposal in the design of chemical reactions. Sulfolane a colorless, water soluble, non-toxic, bio- degradable, and highly polar compound, derives its market value from its exceptional thermal stability, chemical inertness, and solvent properties. Eighteen to twenty million pounds of sulfolane are consumed annually in a variety of applications including extraction of aromatic hydrocarbons, delignification of wood, removal of acidic compounds from natural gas streams, and solutions for polymerization and fibre spinning, electroplating baths, and batteries. In the next several years, regulatory changes and the movement to "environmentally improve" industrial processes could possibly increase the market for sulfolanes by 50% or more. Currently, sulfolane is produced via the reaction of 1,3-butadiene with sulfur dioxide to produce 3-sulfolene, which then undergoes catalytic hydrogenation to yield sulfolane. These reactions are carried out in series in two batch stirred tank reactors. Reaction temperatures are maintained by passing water or steam through heating jackets around each reactor. The first step in the synthesis requires excess sulfur dioxide and is plagued by polysulfone-producing side reactions that limit process yield, poison the hydrogenation catalyst, and present waste disposal problems. Removal of the excess sulfur dioxide by evacuating or purging the reactor and oxidation reactions which produce SOx by-products creates emission problems. The development of improved and alternative methods for the synthesis and processing of sulfolane could eliminate or minimize these environmental concerns, improve energy efficiency, and reduce product cost. Phillips Petroleum, one of the two domestic producers of sulfolane, will be actively involved in this research project.
