Ionic surfactants examples

Amphoteric surfactants have properties similar to either nonionic surfactants or ionic surfactants. Examples are betaines and phospholipids. 

For example, for alkyl (8-16) glycoside (Plantacare 818 UP) non-ionic surfactant solution of molecular weight 390 g/mol, an increase in surfactant concentration up to 300 ppm (CMC concentration) leads to a significant decrease in surface tension. In the range 300 < C < 1,200 ppm the surface tension was almost independent of concentration. In all cases an increase in liquid temperature leads to a decrease in surface tension. This surface tension relaxation is a diffusion rate-dependent process, which typically depends on the type of surfactant, its diffusion/absorption kinetics, micellar dynamics, and bulk concentration levels. As the CMC is approached the absorption becomes independent of the bulk concentration, and the surfactant... 

The raw materials used in a particular product may present some challenges to the formulation chemist when selecting the most appropriate preservative. Problem ingredients may act as microbial nutrients, preservative inactivators or preservative adsorbers and careful testing and assessment of the preservative system is necessary in these cases. One notable example of this is the inactivation of parabens esters by certain non-ionic surfactants. 

There have been some examples of the use of LDMS applied to the analysis of compounds separated via TLC, although not specifically dealing with polymer additives [852]. Dewey and Finney [838] have described direct TLC-spectroscopy and TLC-LMMS as applied to the analysis of lubricating oil additives (phenolic and amine antioxidants, detergents, dispersants, viscosity index improvers, corrosion inhibitors and metal deactivators). Also a series of general organics and ionic surfactants were analysed by means of direct normal-phase HPTLC-LMMS [837]. Novak and Hercules [858] have... 

Many other products can be used as softeners but are less important commercially because of greater cost and/or inferior properties. Examples are anionic surfactants such as long-chain (C16-C22) alkyl sulphates, sulphonates, sulphosuccinates and soaps. These have rather low substantivity and are easily washed out. Nonionic types of limited substantivity and durability, usually applied by padding, include polyethoxylated derivatives of long-chain alcohols, acids, glycerides, oils and waxes. They are useful where ionic surfactants would pose compatibility problems and they exhibit useful antistatic properties, but they are more frequently used as lubricants in combination with other softeners, particularly the cationics. 

As an example of an anionic surfactant mixture frequently contained in detergent formulations, an AES blend with the general formula C H2 i i—O—(CH2—CH2—O) —SO3 was examined in the negative FLAMS mode. Because of the considerable differences observed between both API ionisation mode overview spectra, the ESI—FIA—MS(—) and the APCI—FIA—MS(—) spectra are reproduced in Fig. 2.5.3(a) and (b), respectively. Ionisation of this blend in the positive APCI—FIA—MS mode, not presented here, leads to the destruction of the AES molecules by scission of the O—SO3 bond. Instead of the ions of the anionic surfactant mixture of AES, ions of AE can then be observed imaging the presence of non-ionic surfactants of AE type. 

Quite often the most crucial parameter for SPE of compounds for which no enrichment techniques for environmental samples can be found in the literature is the selection of the proper SPE material. For example, during extraction of the two non-ionic surfactants, alkyl glucamides (AGs) and alkyl polyglucosides (APGs) from a spiked WWTP effluent (5 xgL-1) using RP-C18 cartridges, it was found that this material was unsuitable for quantitative enrichment (recovery <30%). Satisfactory results were obtained using PS-DVB material (Lichrolut EN) [45] (Table 3.1.2). 

Physical properties of the protein structure should be considered in designing strategies to achieve stable formulations because they can often yield clues about which solution environment would be appropriate for stabilization. For example, the insulin molecule is known to self-associate via a nonspecific hydrophobic mechanism66 Stabilizers tested include phenol derivatives, nonionic and ionic surfactants, polypropylene glycol, glycerol, and carbohydrates. The choice of using stabilizers that are amphiphilic in nature to minimize interactions where protein hydrophobic surfaces instigate the instability is founded upon the hydro-phobic effect.19 It has already been mentioned that hydrophobic surfaces prefer... 

Ion pair extraction provides a standard method for estimating ionic surfactants either colorometrically or titrimetrically. For example a cationic surfactant such as cetrimide can be estimated by pairing it with a lipophilic anionic dye such as bromocresol purple. The ion pairing creates a coloured lipophilic ion pair, which can be extracted into an organic solvent such as chloroform and a quantitative measurement of the colour extracted can be made spectrophotometrically. This type of assay is described in the BP for Clonidine Injection and Benzhexol Tablets. 

The adsorption of ionic surfactants creates an adsorption layer of surfactant ions, a Stern layer of counterions and a diffusive layer distributed by the electric field of the charged surface. Every layer has its own contribution to surface tension. For example, the adsorption of dodecyl sulfate (DS") ions from the sodium dodecyl sulfate solution is described by the modified Frumkin isotherm as... 

The common gangue material quartz (silica) is naturally hydrophilic and can be easily separated in this way from hydrophobic materials such as talc, molybdenite, metal sulphides and some types of coal. Minerals which are hydrophilic can usually be made hydrophobic by adding surfactant (referred to as an activator ) to the solution which selectively adsorbs on the required grains. For example, cationic surfactants (e.g. CTAB) will adsorb onto most negatively charged surfaces whereas anionic surfactants (e.g. SDS) will not. Optimum flotation conditions are usually obtained by experiment using a model test cell called a Hallimond tube . In addition to activator compounds, frothers which are also surfactants are added to stabilize the foam produced at the top of the flotation chamber. Mixtures of non-ionic and ionic surfactant molecules make the best frothers. As examples of the remarkable efficiency of the process, only 45 g of collector and 35 g of frother are required to float 1 ton of quartz and only 30 g of collector will separate 3 tons of sulphide ore. 

EXAMPLE 8.1 Reaction Equilibrium and Phase Equilibrium Models of Micellization. Research in which the CMC of an ionic surfactant M+ S is studied as a function of added salt, say M+X, ... 

Derivatives of acyclic olefins can be used as chain transfer agents in these polymerizations. The most effective are those with a terminal double bond. For example, in the ROMP of 248 catalysed by [Ru(H20)6](0Ts)2 the transfer constant (klr/kp) for CH2=CHCH2CH20H is 0.21. The size of the polymer particles produced by emulsion polymerization of 248, using RUCI3 with a non-ionic surfactant, is of the order of 0.03 /zm577. 

One of the central questions in the stability of foams is why are liquid films between two adjacent bubbles stable, at least for some time In fact, a film of a pure liquid is not stable at all and will rupture immediately. Formally this can be attributed to the van der Waals attraction between the two gas phases across the liquid. As for emulsions, surfactant has to be added to stabilize a liquid film. The surfactant adsorbs to the two surfaces and reduces the surface tension. The main effect, however, is that the surfactant has to cause a repulsive force between the two parallel gas-liquid interfaces. Different interactions can stabilize foam films [570], For example, if we take an ionic surfactant, the electrostatic double-layer repulsion will have a stabilizing effect. 

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