Carboxylated nonionics

Latex Types. Latexes are differentiated both by the nature of the coUoidal system and by the type of polymer present. Nearly aU of the coUoidal systems are similar to those used in the manufacture of dry types. That is, they are anionic and contain either a sodium or potassium salt of a rosin acid or derivative. In addition, they may also contain a strong acid soap to provide additional stabUity. Those having polymer soUds around 60% contain a very finely tuned soap system to avoid excessive emulsion viscosity during polymeri2ation (162—164). Du Pont also offers a carboxylated nonionic latex stabili2ed with poly(vinyl alcohol). This latex type is especiaUy resistant to flocculation by electrolytes, heat, and mechanical shear, surviving conditions which would easUy flocculate ionic latexes. The differences between anionic and nonionic latexes are outlined in Table 11. 

Alkyl ethoxy carboxylates or carboxylated nonionics, as they are also called, are well known specialty nonionics which can be used as nonionics at neutral pH or as anionics at high pH [19]. Recently amide analogs of these materials have been developed [20], called amide ether carboxylates (Fig. 16). The standard method for making carboxylated nonionics is adding sodium chloroacetate to an ethoxylated alcohol, while the amide analog is made in a similar fashion from an ethoxylated monoethanolamide. 

Ether carboxylates may be determined by TLC on silica. With a developing solvent of 80 20 chloroform/methanol, the ether carboxylate remains near the origin, while the non-carboxylated nonionic portion rises nearly to the solvent front. Carboxylated PEG has an even lower Rf than the ether carboxylate, while PEG has a somewhat lower Rf than the parent nonionic. 2,7-Dichlorofluorescein is a suitable visualization reagent. A more specific visualizer is modified Dragendorff reagent, which serves to differentiate the ether carboxylate from most other anionics, although low ethoxylates, like nonylphenol-3-mole ethoxylate, cannot be detected with useful sensitivity (29,30). As with ethoxylated non-ionics, the ethoxy chain length distribution of ether carboxylates may be determined by TLC (31). 

A very different situation exists m an aqueous solu tion maintained at pH = 7 0 from the situation m pure water We saw earlier that almost all the acetic acid m a 0 1 M solution m pure water was nonion ized At pH 7 0 however hardly any nonionized acetic acid remains it is almost completely converted to its carboxylate ion... 

Fig. 21. Representative nonionic photoacid generators. A variety of photochemical mechanisms for acid production ate represented. In each case a sulfonic acid derivative is produced (25,56,58—60). (a) PAG that generates acid via 0-nitrobenzyl rearrangement (b) PAG that generates acid via electron transfer with phenohc matrix (c) PAG that is active at long wavelengths via electron-transfer sensitization (d) PAG that generates both carboxylic acid and...

Flotation reagents are used in the froth flotation process to (/) enhance hydrophobicity, (2) control selectivity, (J) enhance recovery and grade, and (4) affect the velocity (kinetics) of the separation process. These chemicals are classified based on utili2ation collector, frother, auxiUary reagent, or based on reagent chemistry polar, nonpolar, and anionic, cationic, nonionic, and amphoteric. The active groups of the reagent molecules are typically carboxylates, xanthates, sulfates or sulfonates, and ammonium salts. 

Amphoteric Detergents. These surfactants, also known as ampholytics, have both cationic and anionic charged groups ki thek composition. The cationic groups are usually amino or quaternary forms while the anionic sites consist of carboxylates, sulfates, or sulfonates. Amphoterics have compatibihty with anionics, nonionics, and cationics. The pH of the surfactant solution determines the charge exhibited by the amphoteric under alkaline conditions it behaves anionically while ki an acidic condition it has a cationic behavior. Most amphoterics are derivatives of imidazoline or betaine. Sodium lauroamphoacetate [68647-44-9] has been recommended for use ki non-eye stinging shampoos (12). Combkiations of amphoterics with cationics have provided the basis for conditioning shampoos (13). 

Three generations of latices as characterized by the type of surfactant used in manufacture have been defined (53). The first generation includes latices made with conventional (/) anionic surfactants like fatty acid soaps, alkyl carboxylates, alkyl sulfates, and alkyl sulfonates (54) (2) nonionic surfactants like poly(ethylene oxide) or poly(vinyl alcohol) used to improve freeze—thaw and shear stabiUty and (J) cationic surfactants like amines, nitriles, and other nitrogen bases, rarely used because of incompatibiUty problems. Portiand cement latex modifiers are one example where cationic surfactants are used. Anionic surfactants yield smaller particles than nonionic surfactants (55). Often a combination of anionic surfactants or anionic and nonionic surfactants are used to provide improved stabiUty. The stabilizing abiUty of anionic fatty acid soaps diminishes at lower pH as the soaps revert to their acids. First-generation latices also suffer from the presence of soap on the polymer particles at the end of the polymerization. Steam and vacuum stripping methods are often used to remove the soap and unreacted monomer from the final product (56). 

Carboxylic Amides. Carboxyhc amide nonionic surfactants are condensation products of fatty acids and hydroxyalkyl amines. 

Wool is dyed from aqueous solutions. The majority of dyes used on wool are sodium salts of aromatic anions. Water solubiUty is usually provided by sulfonic acid groups, but in a few cases carboxyl or hydrophilic, nonionic substituents are used. 

The conversion of the nonionic to the ether carboxylate depends, among other things, on... 

Ether carboxylates with two alkyl chains are produced by reacting nonionics with dichloroaceticacid and a 50% solution of NaOH in water under vacuum at temperatures between 115°C and 120°C [28]. Compounds of the type... 

Gerhardt et al. [34] described three possible ways to prepare alkylphenol-polyglycol ether carboxylates, namely, the method with NaOH and SMCA, the method by oxidation by means of oxygen, and the method whereby the nonionic reacts with acrylonitrile followed by hydrolyses with hydrochloric acid. The synthesis with acrylonitrile forms in contrast to the other two methods, carboxyethylated compounds with the general formula... 

The ether carboxylic acids are weakly dissociated [49], exhibiting nonionic behavior at low pH and anionic behavior at high pH. Due to this dual nonionic and anionic character a good emulsification effect can be achieved [66]. For many applications a high carboxymethylation of 80-90% is preferred [64] to obtain the wanted properties. 

The surface-active properties of ether carboxylates have been compared with soaps as well as with those of nonionic and anionic surfactants in addition, the influence of fatty chain and degree of ethoxylation has been investigated. 

Van Paassen [57], Stroink [61], and Meijer [64] described the influence of fatty chain, ethoxylation degree, and pH on the surface tension. It can be concluded that the ether carboxylates behave at low pH as nonionic surfactants with a lower surface tension than at higher pH, where they behave more as anionic surfactants (Fig. 1). Furthermore a higher EO chain or a shorter fatty chain increases the surface tension. 

From the apparent ionization degree it was concluded that the EO chain probably behaves as part of the headgroup. As with Aalbers [49], a low surface charge of the sodium alkyl ether carboxylate micelles was mentioned. The micelle aggregation number N increases with the C chain much more than for the corresponding nonionic surfactants. In the case of C8 there was no influence of temperature. A small decrease was found with increasing EO, but much smaller than in the case of nonionics. 

Later their use in the pretreatment of cotton was described, i.e., mercerizing [169], boiling off [8,170], and bleaching [170,171], For wool washing and wool treatment ether carboxylates have also been mentioned the detergent effect is better than that of the corresponding nonionics, a pleasant feeling is achieved and there is no corrosion on metal [172],... 

Ether carboxylates have also been used in formulations with ethoxylated amines, ethoxylated and propoxylated nonionics, or ethoxylated castor oil and alkanolamides for one-bath dyeing or printing with cationic and anionic or disperse dyes [176],... 

Besides the use of anionics such as sulfonates and nonionics such as alkyl-phenol ethoxylates, in 1977 the use of ether carboxylates was also described [183] in terms of its excellent temperature, electrolyte, and hard water stability and low interfacial tension, especially in case of the C12-C14 ether carboxylic acid with 4.5 mol EO. 

Adsorption and retention studies of surfactants to sand in high-salinity reservoirs showed no differences between nonionics and ether carboxylates [185— 187] low retention and a positive behavior for good oil recovery has been found. 

Solubilization studies on crude oil by ether carboxylates combined with nonionics have been conducted in the presence of varying amounts of CaCl2 [194]. Good solubility can be obtained when the micellar size is 100 nm and is strongly dependent on the CaCl2 concentration. 

Results described in the literature have resulted in several patents, such as one for the improvement of the transport of viscous crude oil by microemulsions based on ether carboxylates [195], or combination with ether sulfate and nonionics [196], or several anionics, amphoterics, and nonionics [197] increased oil recovery with ether carboxylates and ethersulfonates [198] increased inversion temperature of the emulsion above the reservoir temperature by ether carboxylates [199], or systems based on ether carboxylate and sulfonate [200] or polyglucosylsorbitol fatty acid ester [201] and eventually cosolvents which are not susceptible for temperature changes. Ether carboxylates also show an improvement when used in a C02 drive process [202] or at recovery by steam flooding [203]. 

The premise in this case is that the ether carboxylate and the noncoverted nonionic (also a detergent) as a whole are considered as active content. 

Highly concentrated ether carboxylic acids with a low degree of ethoxylation even at room temperature can give an esterification reaction with the non-converted nonionic, especially with the fatty alcohol, to several percentage points. The result may be that a too low value is found for the ether carboxylate content. This mistake in analysis can be avoided by saponification of the formed ester [238]. Two hundred to 300 mg matter and ca 100 mg NaOH were weighed in a 50-ml Erlenmeyer glass, heated with 20 ml ethanol under reflux, and after cooling supplied with water to 100 ml. Afterward a two-phase titration was carried out. 

Separation of ionic and nonionic compounds of alkyl ether carboxylates can be done by reverse phase ion pair chromatography [241]. 

A method offering the possibility for the separation, identification, and determination of alkyl- and alkylphenol ether carboxylates, even in mixtures with other nonionic and amphoteric substances, is carried out by HPLC using a reverse phase RP18 column and a mixture of methanol, water, and acetonitrile with the addition of an ion-pairing reagent as mobile phase working under isocratic conditions [242]. 

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