Sodium palmitate

Fig. 1. Binary soap—water phase diagram for sodium palmitate (4). Courtesy of Academic Press, Ltd.

For sodium palmitate, 5-phase is the thermodynamically preferred, or equiUbrium state, at room temperature and up to - 60° C P-phase contains a higher level of hydration and forms at higher temperatures and CO-phase is an anhydrous crystal that forms at temperatures comparable to P-phase. Most soap in the soHd state exists in one or a combination of these three phases. The phase diagram refers to equiUbrium states. In practice, the drying routes and other mechanical manipulation utilized in the formation of soHd soap can result in the formation of nonequilibrium phase stmcture. This point is important when dealing with the manufacturing of soap bars and their performance. 

Reactions.—Dissolve a small quantity of the acid in caustic soda solution and add salt. Sodium palmitate separates as a curdy white piecipitate. 

Boil another portion of the acid with caustic soda and let it cool. Pour off the liquid from the crust of sodium palmitate, which forms on the surface, wash once or twice with... 

In certain cases it is impossible to satisfy both and there is a decrease in solubility of the least successful component. For example, a soap such as sodium palmitate, which in water is mainly... 

Already in 1943 M. Schuler [2] described the comparison of the surface-active properties of sodium palmitate with several ether carboxylates based on a constant amount of C atoms. The results showed that with more O bridges the optimal surface activity and emulsifying properties can be achieved at lower temperature, with the detergent properties decreasing and solubility increasing. 

Addition of as little as 5% soap to an amphoteric LSDA of limited water solubility (high Krafft point) brought about a substantial lowering of the Krafft point and thus markedly improved water solubility. On the other hand, addition of 10% of amphoteric LSDA to sodium palmitate lowered the Krafft point of the soap by 10-14°C. Addition of anionic LSDA to sodium palmitate showed smaller Krafft point depression. Addition of a builder-type salt, such as sodium metasilicate, had essentially no effect on the Krafft points of soap-LSDA mixtures. 

Carboxylates (9.4, where R is the long-chain hydrophobe and X the cation) represent the oldest type of surfactants, since they could be obtained from naturally occurring fats and oils long before the advent of the petrochemical industry sodium heptadecanoate (9.5), for example, incorporates the cetyl group as hydrophobe. Sodium stearate, sodium palmitate and sodium oleate are the simplest carboxylates generally used as surfactants. Alkylaryl compounds (9.6) are also known. 

Sodium nitroprusside, 74 536 Sodium nonoxynol-25 sulfate cosmetic surfactant, 7 834t Sodium oleoyl isethionate cosmetic surfactant, 7 834t Sodium orthophosphates, 73 8321 Sodium orthosilicates commercial, 22 465, 466t, 469t manufacture of, 22 464, 465 Sodium oxide(s), 2 273, 22 765 in cement, 5 468 contamination by, 22 776 Sodium ozonide, 79 417 Sodium palmitate, as soap, 22 726 Sodium pentaborate... 

The product of hydrolysis is naturally an acid soap of varying composition. In any dilute solutions of sodium palmitate it approaches that of the sodium hydrogen soap NaHTg. McBain and Taylor found that the acid soap at 90 0. had the composition HP.2NaP. 

Anionic They are sodium salts of higher fatty acids e.g, sodium palmitate (Ci5H3iCOONa), Sodium stearate (Ci7H35COONa). 

Sodium palmitate [408-35-5] M 278.4, m 285-201 . Crystd from EtOH and dried in an oven. 

Palmitic acid is present as cetyl ester in spermaceti from which, by hydrolysis, the acid may be obtained it is present in bee s wax as the mehssic ester and in most vegetable and animal oils and fats, in greater or lesser amounts, as glyceryl tripalmitate or as mixed esters, along with stearic and oleic adds, Palmitic acid is separated from stearic and oleic acids by fractional vacuum distillation and by fractional crystallization. With NaOH, palmitic add forms sodium palmitate, a soap, Most soaps are mixtures of sodium stearate, palmitate, and oleate. 

Palmitate. Sodium palmitate. NaC16H3i02. white solid, soluble, froth or foam upon shaking the II2O solution (soap), formed by reaction of NaOH and palmitic acid (in alcoholic solution) and evaporating. Used as a source of palmitate. 

The hydrophilic part of the most effective soluble surfactants (e.g. soaps, synthetic detergents and dyestuffs) is often an ionic group. Ions have a strong affinity for water owing to their electrostatic attraction to the water dipoles and are capable of pulling fairly long hydrocarbon chains into solution with them for example, palmitic acid, which is virtually un-ionised, is insoluble in water, whereas sodium palmitate, which is almost completely ionised, is soluble (especially above its Krafft temperature - see page 93). 

Is the pH of solutions containing these salts likely to be acidic, basic, or neutral NaCl, Nal, NH4C1, cocaine hydrochloride, sodium acetate, sodium palmitate. 

NaCl (neutral), Nal (neutral), NH4C1 (acidic), cocaine hydrochloride (acidic), sodium acetate (basic), sodium palmitate (basic). 

The exergy flow diagram, Figure 2, shows the results of the exergy balances on the various zones of the system. The reference state of zero exergy was taken as P0=l atm, TQ=528 R, mass fraction water"0.3, mass fraction sodium palmitate=0.7. 

Glyceryl dioleate monopalmitatc glycerol i 2 sodium oleate - sodium palmitate... 

Esters can be decomposed by boiling with strong alkali, such as sodium hydroxide. This treatment forms the alcohol and the sodium salt of the carboxylic acid. When fat is boiled with sodium hydroxide, glycerine and sodium Milts of the fatty acids, sodium palmitate, sodium itearate, and sodium oleate, are formed. These sodium salts of the iitty acids are called soap. 

Which do you think is the more soluble in water, sodium palmitate or ethyl palmitate In benzene ... 

The favored structure for most phospholipids and glycolipids in aqueous media is a bimolecular sheet rather than a micelle. The reason is that the two fatty acyl chains of a phospholipid or a glycolipid are too bulky to fit into the interior of a micelle. In contrast, salts of fatty acids (such as sodium palmitate, a constituent of soap), which contain only one chain, readily form micelles. The formation of bilayers instead of micelles by phospholipids is of critical biological importance. A micelle is a limited structure, usually less than 20 nm (200 A) in diameter. In contrast, a bimolecular sheet can have macroscopic dimensions, such as a millimeter (10 nm, or 10 A). Phospholipids and related molecules are important membrane constituents because they readily form extensive bimolecular sheets (Figure 1211). 

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