A review with 65 refs. on high-performance liq. chromatog. of nonionic surfactants. [on SciFinder(R)]

Bromination, chlorination, and hydroxylation were carried out on the hydrophobic chain of several com. available nonionic surfactants (Brij, Mapeg, and polyglycerol oleates) in order to modify their hydrophobic characteristics without changing their hydrophilic moieties. Paraffinic oil-in-water emulsions could be stabilized using these new surfactants. The derivatization of the nonionic surfactants increased their overall hydrophilicity, and as a result higher HLB values were obtained for the surfactants. In spite of the fact that hydrophilic groups were introduced into the hydrocarbon chain, stable emulsions were prepd. and in some cases even better stabilities were obsd. [on SciFinder(R)]

The hydrogenation of soybean oil Me esters using aq. formic acid salt (esp. K formate) solns. and heterogeneous Pd/C catalyst was investigated. Complete hydrogention of Me ester was achieved by mixing a concd. aq. alkali formate soln. with the Me ester at 80° in the presence of the catalyst (0.2-0.4% Pd). During the initial stages of the reaction, the selectivity was significantly higher than conventional hydrogenation (hydrogenation under pressure) performed with the same catalyst. Cis-trans isomerization was similar to the behavior of conventional techniques. [on SciFinder(R)]

The role of selected emulsifiers on fat polymorphic transformations was studied. Tristearin was heated or aged under controlled conditions using differential scanning calorimetry (DSC) and x-ray techniques, and the extent of transformation was evaluated with respect to the possible pathways of $\alpha$ transforming into $\beta$. The temp. regime controls the extent of mobility of fat mols., the local crystal imperfections and the degree of liquefaction. As a result, it dictates the kinetics of the polymorphic transformation. The surfactant added as an impurity does not have a straightforward effect, as thought previously, but rather varies with the kinetic conditions. During aging some selected solid emulsifiers will retard the $\alpha$-$\beta$ transformation while others still enhance it (during heating, all of them will inhibit $\beta$ form crystn.). Their effect probably is related to different cryst. organizations and the creation of imperfections. Liq. emulsifiers in any case will enhance the $\alpha$-$\beta$ transformation, due probably to their weak structure compatibility with tristearin, which causes a higher mobility of triglyceride mols. [on SciFinder(R)]

Microsuspension polymn. of vinyl chloride (I) catalyzed by diacetyl peroxydicarbonate in the presence of Shamtonate 333 (a petroleum sulfonate in hydrocarbon oil) and Berol 259 yielded spherical, smooth PVC particles of 1-3 $μ$ diam. The addn. of butylene glycol further improved the stability and particle size distribution in the microsuspension system. Polymn. of I with conventional emulsifying agents such as Na lauryl sulfate, ammonium laurate, Methocel K35, Aerosol AT, and Myrj 49 yielded aggregated PVC particles due to inversion of the emulsion to a water-in-oil system. Stable emulsions were obtained for CH2Cl2 (as model compd. for I) but not for I in the presence of nonionic emulsifiers alone. [on SciFinder(R)]

The food-grade rutile TiO2, was dispersed in coconut oil with the help of hydrophobic emulsifiers such as sorbitan esters and lecithin. The dispersed mixt. was melted and blended with hydrophilic emulsifiers such as ethoxylated sorbitan esters and the preheated (60°) blend was further sprayed by atomizer into cold water (20°). The oil-in-water emulsions contained encapsulated TiO2 in the internal phase. The technique is simple and allows prepn. of stable emulsions with av. droplet size of 1-10 $μ$. [on SciFinder(R)]

Sorbitan esters and other solid emulsifiers had no effect on the x-ray diffraction patterns of the stable $\beta$ polymorphs of trilaurin [538-24-9] and tristearin [555-43-1]. Plots of heat capacities (C+) of the polymorphs vs. temp. had divergence points with increase of slope at the onset of 2-dimensional melting. Sorbitan esters did not affect the Cp values of tristearin below the divergence point but increased the values for only the $\beta$-form above this point. Acridan [92-81-9] and Dimodan [31566-31-1] increased the Cp of tristearin in both forms through the whole range of temp., up to melting. Phase diagrams of tristearin with 2 sets of emulsifiers were constructed. All solid emulsifiers could be incorporated in tristearin forming one phase, but tristearin could be similarly incorporated only in sorbitan esters. Sorbitan esters increased the value of the heat of fusion of $\alpha$-trilaurin whereas other solid emulsifiers did not. Explanations were suggested by taking into account the degree of structural compatibility between the triglycerides and the solid emulsifiers. [on SciFinder(R)]

The effect of additives on the rate of release of a drug (or a marker) from the internal phase of a multiple emulsion (water/oil/water) (w/o/w) without causing a decrease in its stability was studied. Electrolytes were added to the internal and/or external aq. phase in order to equalize osmotic pressures of the two aq. phases. Addn. of electrolytes to the outer phase does not slow the rate of drug migration while incorporation of electrolytes and drug to the inner phase decreases the leaching rate. The electrolytes, both cations and anions, which improve the salting-in effect of the emulsifier are effective in decreasing the drug transport. The drug transport can be controlled by altering the electrolyte-surfactant interaction at both interfaces. The right balance between counter-current flow of electrolytes and water in each direction is crit. for such control. [on SciFinder(R)]

A review with 22 refs. The compn. of amino acids in kidney stone matrixes and inhibitory materials from normal urines is discussed. The amino acid factor (FAA) proposed is FAA = (Glutamic acid)/(Aspartic acid + Alanine); its value in fractions of non-potent inhibitory material and in kidney stone matrixes is \textless0.6. In potent portions of the inhibitory material sepd. from healthy people and young animals' urine the value is ≥0.8. The role of enzymes in calcium oxalate stone formation and the exptl. evidence of acidic amino polymers and monomers effect on calcium oxalate crystn. are also discussed. [on SciFinder(R)]

Bromination, chlorination, and hydroxylation of the hydrophobic chains of com. available polyethylene glycol oleyl ether [9004-98-2], polyethylene glycol monooleate [9004-96-0], and polyglycerol esters resulted in surfactants with improved hydrophobic properties and unchanged hydrophilic moieties. The modified surfactants stabilized paraffinic oil in water emulsions. The derivatization of the nonionic surfactants increased their HLB value. The ability of the surfactants to stabilize the emulsions was not due to increased sp. gravities but rather due to the fact that better steric arrangement on the interface was obtained. [on SciFinder(R)]

Bromination of the arom. ring of ethoxylated nonylphenols produced surfactants which were effective emulsifiers for oil-in-water emulsions and which had slightly higher HLB values than their nonbrominated analogs. The bromination increased the sp. gr. to values higher than that of water, allowing formation of oil-in-water emulsions with denser droplets. Initial bromination caused an increase in viscosity while further bromination decreased viscosity. The refractive index increased with increasing oxyethylene chain length and bromination. Crit. micelle concns. for the brominated surfactants were lower than those for the nonbrominated surfactants. Bromination decreased the surface excess concn. values for the compds. [on SciFinder(R)]

The esterification of glyceryl monostearate [31566-31-1] with maleic anhydride [108-31-6] was studied by anal. wet and GLC methods to parameterize and optimize the reaction and maximize the desired yield. Prolonged esterification and temps. \textgreater110-120° increased the diglyceride and hydrophobic product yield. Higher molar ratios of ester to anhydride increased esterification yield. The mechanism and kinetics of the reaction were also detd. [on SciFinder(R)]

The polymorphic behavior of cocoa butter in the presence of several food emulsifiers serving as crystal structure modifiers was investigated. Emphasis was placed on transitions among the relatively stable forms IV, V and VI, which are significant for a confectionery industry. As known from industry work, within the series of sorbitan esters and ethoxylated sorbitan esters, the solid emulsifiers were the most efficient in retarding transition of V form into VI modification. Blends of sorbitan monostearate (Span 60) [1338-41-6], ethoxylated sorbitan monostearate (Tween 60) [9005-67-8] and Span 60-Tween 65 [9005-71-4] were particularly effective. Surprisingly, some combinations of emulsifiers accelerate the transition of form IV into form V. Transition of form V into form VI occurs via the solid state, and other transitions are known to take place via the liq. phase. Emulsifiers increased liq. fraction of the fat prior to its transition. Mechanistic considerations concerning these transitions are suggested. [on SciFinder(R)]