Ecovyst Inc.
A specialty chemicals company that regenerates sulfuric acid for oil refineries and makes catalysts and silica-based materials used in refining, emissions control, and cleaner fuels. Its roots stretch back to 1831, when a Quaker named Joseph Elkinton opened a soap-and-candle shop in Philadelphia that later became PQ Corporation, maker of sodium silicate "waterglass." The company renamed itself Ecovyst in 2021 after selling its performance-chemicals business to focus on sustainability-minded products.