Betaines alkyl chain length

Alkyl chain length is most readily determined by HPLC, as discussed in Chapter 7. NMR analysis has been proposed for assay of betaines, using the signal at 3.3 ppm versus trimethylsilylpropionate. Trimethylsilylpropionate can be used as the internal standard for... 

C ()-Ci8 alkyldimethylaminoacetate betaine after derivatization with 4-bromomethyl-7-methoxycoumarin elution in order of increasing alkyl chain length determination in the presence of other surfactants Cg-Ci8 alkylamidopropylbetaine elution by increasing alkyl chain length determination in cosmetics and... 

C 2-Cix alkylamidopropyldimethyl-aminoacetic acid betaines elution by decreasing alkyl chain length separation from cationics determination in shampoo... 

Cocoamidopropyl-iV,iV-dimethylbetaine, cocoam ido betaine, A/- 3-(cocoamido)-propyl -A/-(2-hydroxy-3-sulfopropyl)-N,W-dimethyl betaine, lauriminodi-propionic acid separation by alkyl chain length MerckRP-18p254 80 20 EtOH/aqueous 2% tetraphenylborate Fluorescence quenching 14... 

The components of a technical cocamidopropyl betaine (CAPB Fig. 2.13.1) mixture were separated under reversed phase conditions in the order of increasing length of the alkyl chain (Fig. 2.13.2) [1]. Since the hydrophobic moiety of the surfactant molecule is derived from coconut oil, the two homologues Ci2 and C14 form the major constituents according to the distribution in the natural raw product containing approximately 49% of Ci2- and 19% of C14-fatty acid [2],... 

The synthesis of these surfactants involves several steps. The first step is the preparation of a substituted imidazoline, usually l-(hydroxyethyl)-2-alkyl imidazoline, starting from fatty acids or fatty acid methyl esters and aminoethylethanolamine (AEEA) (Figure 15.15). For the production of betaines, the choice of fatty material is in most cases hydrogenated coco fatty acid. The distribution composition of fatty acid chain lengths, given above in Table 15.2, is typical also for cocoam-phoacetates. 

Surface tension measurements of betaines, especially of alkyldimethyl betaines, have been reported repeatedly. For alkyl betaines with increasing chain lengths of the alkyl group, the results for surface tensions above the CMC, given in Table 15.6, have been reported (41). 

FIGURE 4 Plots of In cmc versus hydrocarbon chain length at 25°C, unless otherwise stated A, alkyl hexaoxyethylene glycol monoethers B, alkyl sulfinyl alcohols C, alkyl glucosides D, alkyl trimethylammonium bromides in 0.5 M NaBr E, A/-alkyl betaines and F, alkyl sulfates in the absence of added salt at 40°C. [Composite from Tanford, C. (1980). The Hydrophobic Effect Formation of Micelles and Biological Membranes, Wiley, New York.]... 

Most marketed CAPB solutions contain -30% active matter. This is, primarily, because aqueous betaine solutions form viscous, gel-like phases at slightly higher concentrations. In contrast to the situation for surfactants like lauryl ether sulfates, fluid mesophases consisting of CAPB, NaCl, and water do not exist at higher concentrations. The critical concentrations above which nonflowable gel phases are formed partly depend on the length of the fatty acid alkyl chains. 

The addition of acrylic acid to high-percentage imidazolines improves the existence of an imidazolinium betaine in the model substance l-hydroxyethyl-2-heptyl-imidazolinium-3-ethyl carbox-ylate through purification by vacuum distillation [36]. The preparation is carried out by heating the imidazoline derivative for several hours with a 5% excess of acrylic acid in the absence of water. More than 65% of the imidazolinium structure is retained depending on the length of the fatty alkyl chain. Open-chain reaction products are also formed, by application of excess acrylic add, depending on the reaction temperature. 

Fig. 4. Variation of In(cmc) versus hydrocarbon chain length at 25 °C for various surfactants in aqueous media (A) n-alkyl hexa-oxyethylene glycol monoethers [19]. (B) n-alkylsulfinyl alcohols [20], (C) n-alkyl glycosides [19], (D) n-alkyltrimethylammoniurn bromides in 0.5 M NaBr [17,21], (E) n-alkyl betaines [221, (F) alkyl sulfates in pure water [2]. (Redrawn with changes)...

Anionic Surfactant Blend and Amphoteric Surfactants onto Berea Sandstone, Indiana Limestone, Baker Dolomite, and Quartz. The first study to be presented examined the adsorption behavior of two amphoteric surfactants, a betaine (Empigen BT) and a sulfobetaine (Varion CAS) and a 50 50 blend of a Cio diphenyl ether disulfonate (DOWFAX 3B2), and a Ci4 i6 ot-olefm sulfonate [11]. The anionic surfactant blend was designated as DOW XS84321.05. The Cio diphenyl ether disulfonate surfactant is one isomer in a suite of surfactants which differ in their degree of alkylation and sulfonation and in their chain lengths. This suite consists of monoalkyl disulfonates (MADS), dialkyl disulfonates (DADS), monoalkyl monosulfonates (MAMS), and... 

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