CAS 877-24-7 appears in our catalog under these names: Potassium hydrogen phthalate, 99% , Potassium hydrogen phthalate, primary standard, ACS, 99.95- , Potassium hydrogen phthalate, 0.05N Standardized Solution . Offered by: Thermo Scientific (Alfa Aesar). Available pack sizes: 1000g, 5000g, 250g, 1kg, 500ml, 1L.