21921-96-0 BRN 2204649 Ethyl hydrogen 1-propylphosphonate Ethyl hydrogen propylphosphonate Ethyl propylphosphonate Monoethyl propylphosphonate NIA 10637 Niagara 10637 O-ETHYL HYDROGEN PROPYLPHOSPHONATE Phosphonic acid, propyl-, ethyl ester (7CI) Phosphonic acid, propyl-, monoethyl ester