Ethoxylated alkylphenol surfactants

Marquez N, Graciaa A, Lachaise J, Salager JL (2002) Partitioning of ethoxylated alkylphenol surfactants in microemulsion-oil-water systems Influence of physicochemical formulation variables. Langmuir 18 6021-6024... 

Recent work on the partitioning of ethoxylated alkylphenol surfactants (51) has shown that the energy of transfer of a surfactant molecule from water to oil, AC can be written as ... 

In the 1990s, the thmst of surfactant flooding work has been to develop surfactants which provide low interfacial tensions in saline media, particularly seawater require less cosurfactant are effective at low concentrations and exhibit lower adsorption on rock. Nonionic surfactants such as alcohol ethoxylates, alkylphenol ethoxylates (215) and propoxylates (216), and alcohol propoxylates (216) have been evaluated for this appHcation. More recently, anionic surfactants have been used (216—230). 

Ethylene oxide is an important intermediate chemical not only for the production of nonionic surfactants like fatty alcohol ethoxylates, alkylphenol ethoxy lates, or propylene oxide/ethylene oxide block copolymers, but also for manufacturing of anionic surfactants like alcohol ether sulfates. 

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]. 

Oil-in-water emulsions provide a cost-effective alternative to the methods mentioned previously, namely, heating or diluting. A typical transport emulsion is composed of 70% crude oil, 30% aqueous phase, and 500 to 2000 ppm of a stabilizing surfactant formulation [1497]. Nonionic surfactants are relatively insensitive to the salt content of the aqueous phase ethoxylated alkylphenols have been used successfully for the formation of stable emulsions that resist inversion. 

As a test, surfactant slug flow experiments were performed in clayey sandpacks with and without the injection of a desorbent behind the micellar slug. Results show that a substantial decrease in surfactant retention is obtained in calcic environment by such an additive. Likewise, the ethoxylated cosurfactant in the micellar slug can be remobilized simultaneously with sulfonatewithout any change in its ethylene oxide distribution. The application of the RST to sulfonate/ ethoxylated alkylphenol mixtures explains semi-quantitatively the relationship between their properties and composition. 

The theory of regular solutions applied to mixtures of aromatic sulfonate and polydispersed ethoxylated alkylphenols provides an understanding of how the adsorption and micellization properties of such systems in equilibrium in a porous medium, evolve as a function of their composition. Improvement of the adjustment with the experimental results presented would make necessary to take also in account the molar interactions of surfactants adsorbed simultaneously onto the solid surface. 

The quantitative environmental analysis of surfactants, such as alcohol ethoxylates, alkylphenol ethoxylates (APEOs) and linear alkylbenzene sulfonates (LASs), is complicated by the presence of a multitude of isomers and oligomers in the source mixtures (see Chapter 2). This issue bears many similarities to the quantitation problems that have occurred with halogenated aromatic compound mixtures, e.g. polychlorinated biphenyls (PCBs) [1]. 

In general, the main pollution problems associated with surfactants can be summarized as (1) foaming in river and wastewater treatment plants [314,326, 344,348,349,356,357], (2) transformation to bioactive metabolites (i.e., poly-ethoxylated alkylphenols, estrogenic compounds) under aerobic and anaerobic conditions [315,356], and (3) formation of certain cationics which are toxic to microorganisms at high concentrations [356,357]. 

Phenolic compounds are used in commercial or consumer products or building materials (Rudel et al., 2001), especially ethoxylated alkylphenols of octylphenol and nonylphenol, which are widely used in surfactants (Ying, Williams and Kookana, 2002). They are known as endocrine disrupting compounds (EDC) as they bear hormonally active properties. Other EDCs found indoors include phthal-ates (Section 11.2.7), certain pesticides, organotin compounds (Section 11.2.5) and polybrominated diphenyl ethers (Section 11.2.8) (Rudel et al., 2001, 2003). 

A wide range of surfactant types may be used to form and stabilize transport emulsions. Nonionic surfactants have the advantage of relative insensitivity to the salt content of the aqueous phase being employed (6). The group of surfactants known as ethoxylated alkylphenols, represented by the formula,... 

A third class of industrial chemical biocides consists of agents with the ability to inhibit biological film formation, also called surfactants . The term surfactant originates from the phrase surface active agent. Surfactants fall into four broad categories anionic (e.g., soaps, alkyl benzenesulfonates, alkyl sulfonates, alkyl phosphates), cationic (e.g., quaternary ammonium salts), nonionic (e.g., alkyl polyglycosides, alcohol ethoxylates, alkylphenol ethoxylates), and zwitterionic. 

Alkylphenol ethoxylates are important kinds of nonionic surfactants. A characteristic feature of the catalytic ethoxylation of alkylphenols is the enhanced reactivity of phenol hydroxyl for ethylene oxide in comparison with alcohols. Esters of ethylene glycol and alkylphenol behave already as an alcohol. Therefore di-, tri-, and m-mers are allowed to form only after the complete consumption of the starting material. All commercial ethoxylated alkylphenols are mixtures of oligomer-homologues having a Poisson-like distribution with some PEG and catalyst as impurities. Both alkylphenols and dialkylphenols are useful for ethoxylation as a hydrophobic moiety. Among the alkylphenols, isooctylphenol and isononylphenol are most widely used. They are synthesized by the Friedel-Crafts alkylation of phenol with butene dimer and mixture of propene trimers, respectively. 

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. 

The surfactant concentration has a great effect on the decrease in the dispersity degree of the emulsions. An abrupt decrease in the droplet size becomes appreciable with addition of even small surfactant amounts—0.25% of ethoxylated alkylphenol. This dispersity increase unequivocally leads to an increase in sedimentation stability. 

The plasticising activity of ethoxylated alkylphenols and EO/PO block-copolymers depends on the number (m) of the EO units in a surfactant molecule. Ethoxylated alkylphenols with m>40 have a substantial effect on the viscosity reduction of HWCS. It may be connected with the fact that they can form rather thick hydrated layers when adsorbing on the particles, which play the role of a structure-mechanical barrier. The addition of ethoxylated alkylphenols with m<40 produce a thickening effect on the suspensions which may be connected with the features of coal particle wetting by aqueous surfactant solutions. 

The effect of temperature and surfactants on the viscosity of coal-water mixtures is shown in [281]. It has been shown that the volume content of coal in suspension can be increased while preserving its flowability at a certain surfactant content. Stable and pseudo-plastic suspensions were obtained both with anionic surfactants containing electrolyte, and with ethoxylated alkylphenols with a high content of oxyethylene groups. But the rate of reduction of the apparent viscosity begins to decrease with increasing temperature which seems to be connected with the change of the surfactant structure in solution and adsorption layers. 

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. 

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