Optimization of a hydrogen bromide fission procedure for nonyl- and dinonylphenol polyethoxylates and their o-phosphate esters

Nonyl- and dinonylphenol polyethoxylates ( NPEOs, DNPEOs ) and their o -phosphate esters are widely used as surfactants in various industrial, agricultural and domestic applications. An HBr-fission procedure was developed for cleaving NPEOs, DNPEOs and their o -phosphate esters to nonylphenol ( NP ) and dinonylphenol ( DNP ), and their bromine adducts, thereby facilitating the analysis of NP- and DNP contents in complex NPEO- and DNPEO-containing samples. The procedure includes fission, liquid-liquid extraction and GC-MS analyses of the fission end-products. Using 2 × 2 factorial experimental designs, 2 h cleavage at 120°C was found to provide optimal yields of the target compounds, with minimal unwanted by-products. The calculated accuracy for the cleavage of NP10EO to NP was 95% and the limit of NP/DNP detection of the presented method was 5 mg/L.