Alkylphenol Ethoxylates: Products Chemistry
APEs are produced by the based-catalyzed reaction of an alkylphenol (AP) with ethylene oxide (EO). In the case of NPEs, the branching of the nonyl group results in a variety of structural isomers with one isomer shown below:
Commercially available, NPEs generally range from four moles of ethoxylation (NPE4) up to 80 moles of ethoxylates (NPE80). While some CAS RNs specific to certain levels of ethoxylates do exist, the commercially relevant NPE CAS RNs discussed below are applicable to all levels of ethoxylation. By far the most commonly used NPE is manufactured to a target of nine moles of ethoxylation (NPE9). It is important to note that all NPE products are polymers with varying levels of ethoxylation distributed in a normal curve around a target ethoxylation level. The figure below provides an illustration of the oligomer distribution for NPE9
Following is a list of the commercially relevant CAS RNs for NPEs that are known to the Alkylphenols & Ethoxylates Research Council. While these CAS RNs differ with respect to their level of description regarding branching and position of the nonyl group on the phenol ring, APERC understands that manufacturers of NPEs use essentially the same starting materials and synthesis process and, therefore, commercially available NPEs have essentially the same structure and isomeric mix. Thus, the various CAS RNs are generally considered as equivalent synonyms for NPE.