Sodium lauryl alcohol sulphate

All equipment allows production of 40% active alkylbenzene sulphonate and 30% active sodium lauryl alcohol sulphate products. Normally, the equipment also allows production of other products such as high active (50-60%) all lbenzene sulphonate and 70% AD ethoxylated alcohol sulphates. Specially designed neutralisers of this kind yield products such as 75% AD sodium coconut alcohol sulphate. All these q>tions also hold for the Ballestra Neutrex system discussed in section 5.6.3. 

Since poly(vinyl acetate) is usually used in an emulsion form, the emulsion polymerisation process is commonly used. In a typical system, approximately equal quantities of vinyl acetate and water are stirred together in the presence of a suitable colloid-emulsifier system, such as poly(vinyl alcohol) and sodium lauryl sulphate, and a water-soluble initiator such as potassium persulphate. 

Emulsifying ointment is made from emulsifying wax (cetostearyl alcohol and sodium lauryl sulphate) and paraffins. Aqueous cream is an oil-in-water emulsion of emulsifying ointment. 

Oil-in-water creams, for topical use, generally contain mixed emulsifiers/surfactants one of which is a water soluble surfactant with a high HLB, the other being an amphiphile, usually a long chain fatty alcohol (e.g., of chain length C14 to Cig) or acid (e.g., palmitic or stearic). The water soluble surfactant may be anionic (e.g., sodium lauryl sulphate), cationic (e.g., cetri-mide), or non-ionic (e.g., cetomacrogol. Tweens). 

Formulations containing an absorption promoting substance, such as propylene glycol or sodium lauryl sulphate, may increase the permeability of the stratum comeum to water-soluble drugs. Propylene glycol is a commonly used vehicle in topical corticosteroid preparations for veterinary use. Various aprotic solvents, which include dimethylacetamide, dimethylformamide, dimethylsulphoxide, tetrahydrofurfuryl alcohol, and 2-pyrrolidone, serve as penetration enhancers of polar drugs (Barry, 1983). Dimethylsulphoxide... 

The viscoelastic properties of the surface layer are important parameters. The most useful technique for studying the viscoelastic properties of surfactant monolayers is surface scattering. When transversal ripples occur, a periodic dilation and compression of the monolayer occurs, and this can be accurately measured, enabling the viscoelastic behaviour of monolayers under equilibrium and nonequilibrium conditions, to be obtained, without disturbing the original sate of the adsorbed layer. Some correlations have been found between surface viscosity and elasticity and foam stability an example of this is the addition of lauryl alcohol to sodium lauryl sulphate, which tends to increase the surface viscosity and elasticity [10]. 

TGA, there were two peaks in the derivative curve. It was concluded that these were due to the loss of free and lamellar water from the cream, and therefore TGA could be used as a QC tool. The lamellar structure of creams can also be confirmed using small angle X-ray measurements (Niemi and Laine 1991). For example, the lamellar spacings of sodium lauryl sulphate and ce-tostearyl alcohol liquid paraffin creams were found to increase in size (from 8.5 to 17.6 nm) as the water content of the cream increased until, at > 60 percent water, the lamellar structure broke down. This was correlated with earlier work that showed that at this point, the release of hydrocortisone was increased (Niemi et al. 1989). 

Water content is adjusted to the total surfactant concentration of 30-42 % wt. The residual sulphite in the product may be oxidised to sulphate. The sulphonation proceeds also well when using partially hydrated crystalline sodium sulphite in a jacketed shear-stress reactor. This process modification is especially appropriate for manufacturing concentrated sulphosuccinate monoesters as flakes or vermicelli (often with plasticisers and fillers added in situ) suitable in mild synthetic soap bars [78]. The Cn-ig alcohols (I), ethoxylated (x2-4 mole EO) alcohols (II), and fatty monoethanolamides (III) esters of sulphosuccinic acid, mainly as sodium and alkanolamine salts, are of most practical importance as very mild high-foaming surfactants useful for personal care products and in wool, fur, and leather treatment. Very mild disodium PEG-5 laurylcitrate sulphosuccinate (in combination with sodium lauryl ethersulphate) serve for cosmetics produced by Witco as "Rewopol SB CS 50". 

Trehalose, sucrose, maltose, fructose, raffinose, lactose, glucose Poloxamer 407, Poloxamer 188, polysorbate 80, polysorbate 20, octoxynol-9, polyoxyethylene-(23) lauryl alcohol, polyxyethylene-(20) oleyl alcohol, sodium lauryl sulphate Sodium sulphate, ammonium sulphate, magnesium sulphate, sodium acetate, sodium lactate, sodium succinate, sodium proprionate, potassium phosphate Cyclodextrins, mannitol, sorbitol, glycerol, xylitol, inositol Ascorbic acid, glutathione... 

Some correlations have been found between surface viscosity and elasticity and foam stability, e.g. when adding lauryl alcohol to sodium lauryl sulphate, which tends to increase the surface viscosity and elastidty [10]. 

Sodium lauryl sulphate, B.P, is a mixture of sodium normal primary alkyl sulphates and can be assayed by the anionic-cationic titration method. The official method requires weighing of the alcohols liberated on hydrolysis it is inadvisable to dry the residue at 105° and is preferably dehydrated by rapid evaporation with small quantities of dry acetone. 

Polymerization is by free-radical-initiated reaction, in either suspension or emulsion processes in water at about SC C. In the suspension process, polyvinyl alcohol, incompletely hydrolysed PVAC, or gelatine, are used as a colloid stabilizer with peroxide initiators. The emulsion process employs emulsifiers, such as sodium lauryl sulphate and water-soluble persulphate initiators. Mass polymerization gives PVC powders with characteristics different from those of suspension polymer. 

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