Ethoxylated surfactants introduction

The postintroduction of hydrophobes could offer an effective alternative to the mutual solubility problems (Chapter 20) encountered in chain-growth copolymerizations. The introduction of difunctional monomers that contain both unsaturation and isocyanate units (e.g., isocyanatoethyl methacrylate or m-isopropenyl a,a-dimethylbenzylisocyanate) with lower cost non-iso-cyanate-containing monomers (45) provides two routes for postmodification. One route could be the copolymerization with methyl acrylate, followed by the reaction of the isocyanate function with an ethoxylated surfactant, then hydrolysis of the methyl acrylate units. 

The bismuth active substances (BiAS) method for the determination of nonionic surfactants with barium tetraiodobismuthate (BaBil4, modified Dragendorff reagent) is used in the standardized (DIN-Norm) procedure in Germany, as well as in other countries. Ba as a hard Lewis acid forms cationic coordination complexes with the polyethoxylate chain of the nonionic surfactants, which are precipitated by [Bim in the presence of acetic acid. The orange precipitate is then dissolved with ammonium tartrate solution, and the released bismuth ions are determined by potentiometric titration with pyrrolidinedithiocarbamate solution. Waters et al. optimized the BiAS procedure by introduction of a cation/anion exchange clean-up of the sublation extracts. The BiAS procedure fails to determine ethoxylates with less than five ethoxy units because these compounds are not precipitated by barium tetraiodobismuthate. Thus, this procedure is not suitable for determination of APEO metabolites, i.e., the shorter APEO and AP. ... 

Mass spectrometric detection allows analysis of most nonionic surfactants without deriva-tization. Thermospray, electrospray, or atmospheric pressure chemical ionization interfaces permit direct introduction of the effluent of the LC into the MS and make the MS a very selective detector for nonionics. Quasimolecular ions are produced for each discrete compound, so that the HPLC system is not required to separate both by degree of ethoxylation and by alkyl character. A relatively simple HPLC separation, coupled with MS anal-... 

---