Life Cycle Environmental and Cost Implications of Isostearic Acid Production for Pharmaceutical and Personal Care Products

Like many specialty chemicals used in pharmaceutical, personal care, and cosmetic products, few life cycle inventory data are available to describe the synthesis of isostearic acids (lAs). We investigate the cradle-to-gate life cycle environmental and economic performances of IA production from soybean oil and tall oil, both renewable resources, using chemical process simulation models that integrated experimental measurement and data from patent literature. Multiple life cycle impact assessment metrics were estimated where the difference in the climate change impact was most significant for the soybean oil process (1.9-3.8 kg of CO2 equivalent/kg of IA) compared to the tall oil process (1-1.5 kg of CO2 equivalent/kg of IA); however, results for both are low on a life cycle basis compared to synthetic lubricants. Considering the value added from coproducts, the unit production cost for the soybean oil pathway was lower than that of tall oil but its profit and return on investment were also lower. Despite these differences, soybean oil remains a promising feedstock for expanding green IA production. Examining hot spots along the soybean oil to IA life cycle, we identify strategies for environmental and economic improvements at the product conversion and recovery stages. We discuss the challenges of predicting the environmental performance of specialty chemicals and new conversion processes and conclude that detailed process modeling like that performed herein is in many cases necessary for capturing environmental trade-offs.