Carboxylated alkylphenol ethoxylates

The trend of discovering the analytical field of environmental analysis of surfactants by LC-MS is described in detail in Chapters 2.6-2.13 and also reflected by the method collection in Chapter 3.1 (Table 3.1.1), which gives an overview on analytical determinations of surfactants in aqueous matrices. Most methods have focused on high volume surfactants and their metabolites, such as the alkylphenol ethoxylates (APEO, Chapter 2.6), linear alkylbenzene sulfonates (LAS, Chapter 2.10) and alcohol ethoxylates (AE, Chapter 2.9). Surfactants with lower consumption rates such as the cationics (Chapter 2.12) and esterquats (Chapter 2.13) or the fluorinated surfactants perfluoro alkane sulfonates (PFAS) and perfluoro alkane carboxylates (PFAC) used in fire fighting foams (Chapter 2.11) are also covered in this book, but have received less attention. 

ABS AE AE/P AES AG AOS APEO APG AS BiAS BM c6(EO)3 CNPEC CTAS D DATS DCPEG DEEDMAC branched alkylbenzene sulfonate alcohol ethoxylate alcohol ethoxylate/propoxylate alkylether sulfate alkyl glucamide a-olefin sulfonate alkylphenol ethoxylate alkyl polyglucoside alkyl sulfate bismuth active substances alkyldimethylbenzyl ammonium triethylene glycol monohexyl ether carboxylated nonylphenoxy carboxylates cobalt thiocyanate active substances R2S10(o.5)2 dialkyl tetralinsulfonate dicarboxylated PEG ditallow ester of di(hydroxyethyl)dimethyl ammonium chloride... 

An exception to the above rule of the thumb is the alkylphenol ethoxylates. Biodegradation of these compounds yields the relatively stable C9APEOm with 0 < m<3 ethoxylate units or the respective carboxylates (Ahel, 1989). These ethoxylated products are more hydrophobic and bioaccumulative (Ekelund et al., 1990 Ahel et al., 1993) than the precursor surfactant molecules and are also of toxicological concern (Granmo et al. 1989, Jobling et al., 1996). 

Simultaneously with the use of PBI for the analysis of pesticides and agrochemicals, both dispersed in large quantities in the environment [109], this interface type was also appHed to perform the determination of a broad spectrum of pollutants generated by degradation processes, mobilized from waste disposals and contained in the leachates [110] and finally found in the aquatic environment The analysis of 500 L samples of drinking water made the pollution of these waters with alkylphenol ethoxylates (APEOs) and alkylphenol carboxylates (APECs) obvious [111]. As polar constituents of wastewater samples non-ionic surfactants of NPEO type and their acidic metaboHtes, plasticizers, and plastic additives could be confirmed by the appHcation of PBI-LC-MS [112]. 

Another common approach to water-based coating formulations is post-emulsification of a polymer in water. Several condensation polymers, e.g. alkyds, i.e. fatty-acid-modified polyesters, polyurethanes and epoxy resins, have been made into dispersions by the use of a suitable emulsifier and application of high shear. For instance, long oil alkyd resins of the type used in white-spirit-based formulations have been successfully emulsified by using nonionic surfactants such as fatty alcohol ethoxylates, alkylphenol ethoxylates or fatty acid monoethanolamide ethoxylates. Neutralization of alkyd carboxylic groups helps in producing small emulsion droplets and with the proper choice of surfactant, droplet diameters of less than 1 pm can be obtained. Such dispersions are sufficiently stable for most applications. 

Several metabolites are formed during the aerobic and anaerobic biodegradation of alkylphenol ethoxylates (APEOs). Significant amounts are found of alkylphenol, mono- and diethoxylated alkylphenols and the equivalent carboxylates, i.e. alkylphenoxyacetic acid and alkylphenoxyethoxyacetic acid. A simplified scheme, according to Thiele et al. (19), of the biodegradation... 

NON-IONIC SURFACTANTS Polyoxyethylenated alkylphenols, alkylphenol ethoxylates Polyoxyethylenated straight- chain alcohols, alcohol ethoxylates Polyoxyethylenated polyoxypropylene glycols Polyoxyethylenated mercaptans Long-chain carboxylic acid esters Alkanolamine condensates, alkanolamides Tertiary acetylenic glycols Polyoxyethylenated silicones N-alkylpyrrolidones Alkylpolyglycosides... 

Two-phase titration is applicable for determination of the carboxylates of alcohol ethoxylates and alkylphenol ethoxylates. The usual indicators do not give sharp end points Safranine T is used instead with a borax pH 8.6 buffer. Poor results are obtained using electrochemical detection of the end point (142,143). Other anionics interfere (144). 

Equation 20 is the rate-controlling step. The reaction rate of the hydrophobes decreases in the order primary alcohols > phenols > carboxylic acids (84). With alkylphenols and carboxylates, buildup of polyadducts begins after the starting material has been completely converted to the monoadduct, reflecting the increased acid strengths of these hydrophobes over the alcohols. Polymerization continues until all ethylene oxide has reacted. Beyond formation of the monoadduct, reactivity is essentially independent of chain length. The effectiveness of ethoxylation catalysts increases with base strength. In practice, ratios of 0.005—0.05 1 mol of NaOH, KOH, or NaOCH to alcohol are frequendy used. 

Ether carboxylates are used not only in powdered detergents but in liquid laundry detergents for their hard water stability, lime soap dispersibility, and electrolyte stability they improve the suspension stability and rheology of the electrolyte builder [130,131]. Formulations based particularly on lauryl ether carboxylate + 4.5 EO combined with fatty acid salt and other anionic surfactants are described [132], sometimes in combination with quaternary compounds as softeners [133,163]. Ether carboxylates show improved cleaning properties as suds-controlling agents in formulations with ethoxylated alkylphenol or fatty alcohol, alkyl phosphate esters or alkoxylate phosphate esters, and water-soluble builders [134]. 

For the evaluation of the foamability of a surfactant the bulk concentration is used at which the relative rate of foam collapse is equal to 50% of its formation (cw °). The cw ° values determined from foam formation isotherms of a number of products are given in Table 6.1. As it is seen, typical representatives of anionics (sodium dodecyl sulphate), cationics (cetyl trimethyl ammonium bromide) and nonionics (ethoxylated alkylphenols) give bubble foams at very low concentrations, and the foam stability of ionic surfactants does not differ much from that of nonionics. For anionics, the highest concentrations are required for soaps of higher carboxylic acids. 

Crystalline carboxylated polypropylene such as Hercoprime G and the car-boxylated amorphous polypropylene such as Epolene E-43 can be used as the base polymer to make polypropylene dispersion (79). To make polypropylene emulsion, the polymer is heated to 170-175°C under 100-120 psig superatom-spheric pressure. Triton X-100, an ethoxylated alkylphenol, or Igepal CO 630, an ethoxylated nonylphenol, can be used as the surfactant. The acid modified polyolefin must be neutralized by a base such as diethyl ethanolamine to maintain the stability of the dispersion. The surfactant is mixed with the molten polyolefin... 

Nonylphenol ethoxylate (NPEO), octylphenol ethoxylate (OPEO), alkylphenoxy carboxylate (APEC), halogenated alkylphenols (BrOP, ClOP, BrNP, CINP), halogenated NPEOs (BrNPEOs, ClNPEOs) Bisphenol-A (BPA), bisphenol-F (BPF)... 

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