Sulfolane: Safer Alternative To NMP

EPA Regulation of NMP

---

NMP solvent (n-methyl-2-pyrrolidone; CAS No. 872-50-4) is widely used in various industrial applications, including paint strippers, coatings, adhesives and materials for electronics manufacturing. However, exposure to NMP can lead to adverse health effects, including reproductive toxicity, skin and eye irritation, and central nervous system problems. Recognizing these dangers, the Environmental Protection Agency (EPA) took action under the Toxic Substances Control Act (TSCA) to evaluate and regulate the use of NMP. The EPA has implemented these regulatory standards to help mitigate the risks associated with NMP while promoting safer alternatives.

In 2017, the EPA proposed to restrict the use of NMP in specific consumer products such as paint strippers, where exposure risks are especially high. The agency conducted a comprehensive risk assessment that highlighted the potential for harmful health effects, particularly among vulnerable people like pregnant women and children. The proposed regulations aim to limit the concentration of NMP in consumer products and require manufacturers to provide adequate labeling and safety information.

While NMP is currently only regulated in consumer products, the EPA encourages manufacturers and industries to seek safer alternative chemicals and processes to NMP. In response to the EPA warning, many companies are exploring less hazardous solutions that can provide similar or better performance.

Innovative Solvents for NMP Replacement

---

A variety of safer solvents are being evaluated to replace NMP. One common alternative chemistry is dimethyl sulfoxide (DMSO), which is considered less toxic and has a similar solvency to NMP. However, DMSO permeates into the skin, and is not an ideal substitute for applications with worker exposure.

Sulfolane, a low-viscosity organosulfur compound, is a low-toxicity NMP replacement that also demonstrates low skin penetration. Because of its highly dipolar, aprotic nature, it provides strikingly similar solvency performance to NMP. This makes it an attractive alternative for industries looking to maintain their formulation efficacy while minimizing health risks. Additionally, sulfolane is soluble in water and extremely stable, even at elevated temperatures up to 430°F, making it particularly advantageous in high-temperature processes. Sulfolane has a wide variety of applications, including paint strippers, coatings, electronic photoresist cleaners, inks, pharmaceuticals, and refinery extraction.

Comparing NMP and Sulfolane

Chevron Phillips Chemical manufactures high-purity grades of sulfolane in the United States in both anhydrous and aqueous versions, catering to the diverse needs of industrial applications. This commitment to producing high-quality solvents ensures that industries can select the most suitable product for their specific processes. Contact us today to request a sample or speak with one of our technical specialists!