Fatty acid soaps effect

The adsorbed layer at G—L or S—L surfaces ia practical surfactant systems may have a complex composition. The adsorbed molecules or ions may be close-packed forming almost a condensed film with solvent molecules virtually excluded from the surface, or widely spaced and behave somewhat like a two-dimensional gas. The adsorbed film may be multilayer rather than monolayer. Counterions are sometimes present with the surfactant ia the adsorbed layer. Mixed moaolayers are known that iavolve molecular complexes, eg, oae-to-oae complexes of fatty alcohol sulfates with fatty alcohols (10), as well as complexes betweea fatty acids and fatty acid soaps (11). Competitive or preferential adsorption between multiple solutes at G—L and L—L iaterfaces is an important effect ia foaming, foam stabiLizatioa, and defoaming (see Defoamers). 

A fatty acid soap in which a polyglycol ether group has been introduced between the fatty chain and the carboxylic group, which transforms some unfavorable properties of soaps into positive characteristics without decreasing the overall positive effects, and... 

Fatty acid soaps are invariably alkaline, having a pH of 9 or higher in dilute solutions. This alkalinity is particularly undesirable in the washing of fine silks and woolens, where it can accentuate fabric shrinkage or color fading. Synthetic detergents have been developed that are neutral and have no more effect than plain water on fine fabrics. 

Effects of added fatty-acid soaps upon mechanical and chemical stability of natural rubber latex (1,2,5)... 

Saturated straight-chain fatty-acid soaps (1). Figure 1 shows the effects of increasing levels of various potassium saturated straight-chain fatty-acid soaps upon the mechanical stability of natural rubber latex. For convenience of making comparisons between the various soaps, the levels of added soap are expressed as moles per 100 g. of latex solids. 

The results summarised in Table I show the effect of equal parts by weight of each of the potassium fatty-acid soaps upon the mechanical stability of each of the three chemically-destabilised latices. For convenience in making comparisons, estimates of the corresponding results for unmodified natural rubber latex are also included. It is clear from these results that the ability of added potassium fatty-acid soaps to enhance the stability of chemically-destabilised natural rubber latex roughly parallels their abilities to enhance the mechanical stability of unmodified natural rubber latex. 

The effects of a range of sodium n-alkyl sulphates and sodium n-alkyl sulphonates upon the mechanical stability of natural rubber latex are summarised in Figures 4 and 5 respectively. As in the case of added potassium fatty-acid soaps, small additions of... 

Table Ii Effect of 0.1 part by weight per 100 parts latex solids of various potassium fatty-acid soaps upon mechanical stability of unmodified and chemically-destabilised natural rubber 1atices (1 )...

Engblom, J., Engstrbm, S. and Fontell, K. The effect of the skin penetration enhancer Azone on fatty-acid soap-water mixtures. Journal of Controlled Release 33 299-305, 1995. 

The only useful commercial catalyst now used is nickel, available at a 17-25% level on a support and suspended in hardened edible oil or tallow. This preserves the activity of the nickel in a form in which it can be safely and easily handled. Catalyst can be recovered and reused but will be less active. Reaction is usually effected at temperatures between 180°C and 200°C and at a pressure of about 0.3 MPa (3 bar). The catalyst is quickly poisoned by fatty acids, soaps, phospholipids, oxidized acids, sulfur compounds, halogen compounds, carbon monoxide, oxygen, and water. As a consequence, both the oil and the hydrogen should be as pure as possible. 

Metal soaps, especially fatty acid soaps of alkaline earth metals have an external lubricating effect in PVC, contribute to good release and are co-stabiUzing. In fact,... 

The use of builders in liquid laundry formulations has effectively been restricted to citrates and fatty acid soaps (in isotropic compositions sold in the U.S. and Europe). Although liquid laundry products can contain tripolyphosphate, soda ash, NTA, and other common builders found in powder laundry, limitations on solubility (in a surfactant matrix) or regulatory concerns have restricted their utilization. There is a finite number of patents covering zeolite-built HDLDs, but problems... 

A relatively new field is the use of flotation in wet textile processes [73]. The ( -potential of cotton fibres in aqueous solutions is negative, therefore they are effectively floated by cationics like quaternary ammonium salts, e.g. dodecyl trimethyl ammonium chloride. Sysilia et al. [74] have established, by measuring the electrokinetic potential, a clear rule between the positive surface charge of chromite and flotation efficiency. At low pH, chromite was effectively floated by fatty acid soaps, the ions of which are negatively charged under these conditions. The surfactant adsorption is reversible which is indicative of its physical nature. 

Other Chemical Methods These methods rely chiefly on destroying the foam stabilizer or neutralizing its effect through methods other than displacement and are applicable when the process will permit changing the chemical environment. Forms stabilized with alkali esters can be broken by acidification since the equivalent free acids do not stabilize foam. Foams containing sulfated and sulfonated ionic detergents can be broken with the addition of fatty-acid soaps and calcium salts. Several theories have been proposed. One su ests that the surfactant is tied up in the foam as double calcium salts of both the sulfonate and the soap. Another suggests that calcium soaps oriented in the film render it inelastic. 

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