Surface-active agents mixtures

Although finely divided insoluble solid particles constitute an important class of emulsifying agents [44-46], the preparation of liquid-liquid dispersions traditionally involves the use of ionic and nonionic small-molecule surface-active agents. Mixtures of surfactants can also be used to achieve a desirable viscosity of emulsions [12] and to enhance the stabilization properties compared to the effect of one of the emulsifiers [47-49], although evidence of synergistic effects are not always found. 

Di- and Triisobutylcncs. Diisobutylene [18923-87-0] and tnisobutylenes are prepared by heating the sulfuric acid extract of isobutylene from a separation process to about 90°C. A 90% yield containing 80% dimers and 20% trimers results. Use centers on the dimer, CgH, a mixture of 2,4,4-trimethylpentene-1 and -2. Most of the dimer-trimer mixture is added to the gasoline pool as an octane improver. The balance is used for alkylation of phenols to yield octylphenol, which in turn is ethoxylated or condensed with formaldehyde. The water-soluble ethoxylated phenols are used as surface-active agents in textiles, paints, caulks, and sealants (see Alkylphenols). 

Albertsson (Paiiition of Cell Paiiicle.s and Macromolecules, 3d ed., Wiley, New York, 1986) has extensively used particle distribution to fractionate mixtures of biological products. In order to demonstrate the versatility of particle distribution, he has cited the example shown in Table 22-14. The feed mixture consisted of polystyrene particles, red blood cells, starch, and cellulose. Liquid-liquid particle distribution has also been studied by using mineral-matter particles (average diameter = 5.5 Im) extracted from a coal liquid as the solid in a xylene-water system [Prudich and Heniy, Am. Inst. Chem. Eng. J., 24(5), 788 (1978)]. By using surface-active agents in order to enhance the water wettability of the solid particles, recoveries of better than 95 percent of the particles to the water phase were obsei ved. All particles remained in the xylene when no surfactant was added. 

Orimulsion is a relatively new fuel that is available for the gasification process. Orimulsion is an emulsified fuel, a mixture of natural bitumen (referred to as Orinoco-oil), water (about 30%), and a small quantity of surface active agents. Abundant Orinoco-oil resei ves he under the ground in the northern part of Venezuela. 

The direct reaction of 1-alkenes with strong sulfonating agents leads to surface-active anionic mixtures containing both alkenesulfonates and hydroxyalkane sulfonates as major products, together with small amounts of disulfonate components, unreacted material, and miscellaneous minor products (alkanes, branched or internal alkenes, secondary alcohols, sulfonate esters, and sultones). Collectively this final process mixture is called a-olefinsulfonate (AOS). The relative proportions of these components are known to be an important determinant of the physical and chemical properties of the surfactant [2]. 

Modem commercial detergents are mixtures. Their most important component is a surfactant, or surface-active agent, which takes the place of the soap. Surfactant molecules are organic compounds with a structure and action similar to those of soap. A difference is that they typically contain sulfur atoms in their polar groups (4). 

W. W. Frenier and F. B. Growcock. Mixtures of a,P-unsaturated aldehydes and surface active agents used as corrosion inhibitors in aqueous fluids. Patent US 4734259, 1988. 

As with surface-active agents, the detailed chemistry of these products is a good deal more complicated than is indicated by the nominal structures frequently quoted. Most commercial products are mixtures of which the nominal structure represents a basic type only. Indeed, the detailed chemistry of the more complex products is still only partially understood. These provisos should be borne in mind when considering the structures given below. 

The stabilizing of aqueous latexes succeeded by using emulsifiers (anionic, nonionic) and/or their mixture, steric stabilizators (polyvinyl alcohol (PVOH), hydroxyethyl cellulose, polyethylene glycol, new protective colloids etc.), and polymerizable surfaces active agents, in general. Vinyl acetate (VAc) emulsion homopolymers and copolymers (latexes) are widely used as binders in water-based interior and exterior architectural paints, coatings, and adhesives, since they have higher mechanical and water resistance properties than the homopolymers of both monomers [2, 4, 7]. 

Thus emulsion technology is basically concerned with preparing mixtures of two immiscible substances, oil and water by adding suitable surface-active agents (such as emulgators, cosurfactants, and polymers). 

It may occasionally be possible to deduce from normal operation that the fluid is not inherently foamy, for example if the normal process boils the mixture (when cooling by reflux condenser) and a stable foam is not produced. However, if runaway might cause surface-active agents to be produced, then there is no substitute for testing under runaway conditions. t. . . 

According to Hino and Yokogava [59] an addition of surface active agents (0.5-1 %) to mixtures of ammonium nitrate with liquid coal-tar improves the trans-... 

Electrochemical fluorination (ECF) is described in Section 6.4.7. for the manufacture of surface-active agents. Coproducts from the ECF of octylsulfonyl fluoride are linear perfluoro-carbons containing from three to eight carbon atoms, while octanoyl fluoride yields a mixture of perfluorocyclic ethers containing mainly perfluoro(2-butyltetrahydrofuran) and perfluoro(2-propylpyran). ECF is also used for the manufacture of specific perfluorocarbon fluids, notably perfluoro(tripropylamine) and perfluoro(tripentylamine), from the corresponding hydrocarbon analogs. 

Fig. 3. Surface inactivation rate of prostatic acid phosphatase by shaking and protection by added surface-active agent. Shaking mixtures (20 ml) contained purified enzyme (056 /ug of protein/ml) in 0.05 M acetate buffer at pH 5.5. The solutions were shaken in 50 ml volumetric flasks using a mechanical shaker (Burrell, model CC). Temperatures were maintained by immersion of the flasks in an appropriately set water bath. After specified intervals of shaking, duplicate 0.1 ml ahquots were removed into tubes containing Triton X-100. All tubes were assayed simultaneously, following the shaking procedure, with 0.05 M phenyl phosphate as substrate. Curve 1 Enzyme + Triton X-100 at 0°C and 29°C. Curve 2 Enzyme alone at 0°C. Curve 3 Enzyme alone at 29°C. From Tsuboi and Hudson (88).

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