Solubilization Behavior of Phorbol Esters from Jatropha Oil in Surfactant Micellar Solutions

Phorbol esters (PEs) are important toxic compounds found in Jatropha curcas oil and pressed seeds. These compounds are tumor promoters; thus, their removal prior to further utilization of the pressed seed is important. This work aimed to investigate the solubilization behavior of PEs and Jatropha oil in nonionic [effect of the ethylene oxide number (EON), carbon‐chain length and temperature] and anionic (NaCl addition) surfactant systems. The results reveal that an increase in the EON of the nonionic surfactant molecules, rather than an increase in the carbon‐chain length, enhances PE solubilization. The hydrophile‐lipophile balance (HLB) value was correlated with PE solubilization for nonionic surfactant solutions. The solubilization of PEs decreased slightly with increasing temperature, in contrast to solubilization of the oil. Moreover, the mole fraction of PE solubilized in the micelle decreased with increasing electrolyte concentration in anionic surfactant solutions. The solubilization behavior of PEs in both nonionic and anionic solutions indicates that PE acts more like a polar compound than a nonpolar compound. In addition, the PEs in nonionic micelles are likely located in the palisade region (i.e., between the head group and the first few carbon atoms of the tail), whereas those in anionic micelles are likely near the outer core of the head group. This finding suggests that a nonionic surfactant with a higher EON has a greater potential to extract PE from Jatropha seeds. If an anionic surfactant is combined as co‐surfactant, a small amount of electrolyte should be added to increase PE solubilization.     

Ethylene oxide oligomer distribution in nonionic surfactants via high performance liquid chromatography (HPLC)

A high performance liquid chromatography (HPLC) method using adsorption columns combined with linear gradient elution has been developed for the determination of ethylene oxide (EO) distribution in nonionic surfactants. The quantitative ethoxylate adduct distribution in single-carbon-number and mixed-carbon-number primary alcohol-based samples can be obtained. The HPLC method is also applicable for determining the molar EO distributions in diverse ethylene oxide adduct compounds such as alkylphenol ethoxylates, branched alcohol ethoxylates and secondary alcohol ethoxylates. Nonionic surfactant samples containing adducts up to 25 mol have been successfully separated and the individual adducts quantitated.     

Solubilization of phospholipid bilayer caused by surfactants

The interaction of surfactants with liposomes eventually leads to the rupture of such structures and the solubilization of the phospholipid components. In this paper, solubilization is regarded as a decrease in light scattering of liposome suspensions. To this end, in accordance with the nomenclature, adopted by Lichtenberg, three parameters were considered as corresponding to the effective surfactant/lipid molar ratios (Re) at which light scattering starts to decrease, Re_sat; reaches 50% of the original value, Re₅₀; and shows no further decrease, Re_sol. These parameters corresponded to the Re at which the surfactant (i) saturated the liposomes, (ii) resulted in a 50% solubilization of vesicles and (iii) led to a total solubilization of liposomes. The surfactants tested were the nonionic surfactant octylphenol ethoxylated with 10 units of ethylene oxide or Triton X-100 (OP-10EO), two anionic surfactants, sodium dodecyl sulfate and sodium dodecyl ether sulfate, and an amphoteric surfactant dodecyl betaine (D-Bet). Unilamellar liposomes formed by egg phosphatidylcholine containing increasing amounts of phosphatidic acid were used. The Re parameters were the lowest for D-Bet, followed by OP-10EO, whereas the anionic surfactants always showed the highest values regardless of the electrical charge of the lipid bilayers. These parameters seem also to be inversely related to the critical micelle concentration (CMC) of the surfactant, except for OP-10EO. Moreover, the CMC values of the surfactant/lipid systems at 0.5 mM lipid concentration corresponded in all cases to the surfactant concentration at which liposomes were saturated by surfactants. As a consequence, this ratio can be regarded as an interesting parameter associated with the mixed micelle formation in liposome solubilization.     

Aqueous solution properties of a silicone surfactant and its mixed surfactant systems

The aqueous solution properties of a nonionic silicone surfactant of dimethylpolysiloxane and its mixed surfactant systems were studied. It was found that the silicone surfactant has a high surface activity and forms micelles in two steps: premicelles in dilute concentrations and polymolecular micelles above 3.7 × 10⁻⁷ mol dm⁻³. In mixed systems of the silicone surfactant with anionic hydrocarbon or fluorocarbon surfactant, weak intermicellar interactions were found. They are due to electrostatic interaction between hydrophilic groups of the respective micelles. Dye solubilization measurements showed that the solubilized amount of Yellow-OB is greater than predicted by ideal systems. Hydrazo-azo tautomerism is observed in fluorocarbon-silicone surfactant systems, while Yellow-OB is solubilized only in the azo-form in the hydrocarbon-silicone surfactant system.     

Removal of fatty soil from glass by surfactants and surfactant-builder compositions

Previous papers have reported radiotagged fatty soil removal from glass either by solvents or by aqueous solutions of sodium tripolyphosphate and other builders. This paper provies soil-removal data for aqueous systems of both pure and built surfactant compositions of the nonionic and alkylbenzene sulfonate types. In general, nonionics are the most effective detergents for the system fatty soil/glass; the 10-mole ethylene oxide adduct products show peak soil-removal. Nonionic surfactants appear most effective for soil removal when used in baths closely approaching their cloud-points. Though modification of hydrophobe by EO addition can affect cloud point, peak soil-removal effectiveness seems to be controlled by hydrophobe selection. Highest soil removal for the alkylbenzene series occurred with the longer alkyl chain (pentadecyl). Admixture of surfactant and sodium tripolyphosphate provided synergistic compositions with certain 10-EO surfactants. Building of anionics markedly improved soil removal over the pure material but seldom exceeded the removal by STP alone. Presented at 34th fall meeting, American Oil Chemists' Society, New York, October 17–19, 1960.     

Electrospray ionization MS of high M.W. TAG oligomers

Reported are the on-line LC/electrospray ionization MS of large, high M.W. oligomers formed from heated triolein, a TAG used as a model for dietary oils. Triolein, the major component of olive oil, canola oil, and other dietary oils, was heated at frying temperature, and the TAG oxidation products were separated using RP-HPLC coupled to an ion trap mass spectrometer via an electrospray ionization interface. Ammonium formate was added as a sheath liquid to promote ammonium adduct formation. Masses corresponding to ammonium adducts of intact carbon-linked dimers (m/z 1783–1787), trimers (m/z 2666–2672), and tetramers (m/z 3547–3557) of triolein, with and without additional sites of unsaturation, were observed. Also, dimers, trimers, and tetramers containing one, two, or three additional oxygens, also with and without additional sites of unsaturation, are reported. Based on the formation of some types of triolein dimers, we believe that tristearin might also form dimers, even though it has no readily oxidizable sites of unsaturation. Oxidized tristearin monomers, tristearin dimers, chainaddition products, and chain-shortened products are observed.     

Removal of radio-tagged protein and stearic acid soil from glass

Both algal protein and stearic acid soils are removed by water alone to near a 50% level; retained soil then becomes more difficult to remove. The bonding of protein soil to glass is stronger than that of tristearin, with indications that stearic acid soil is als slightly more adherent. The shape of the protein soil removal curves lacks the sigmoid shape of the tristearin or stearic acid soils, suggesting either the absence of sharp dependence upon critical micelle concentration, or the existence of adsorption largely at an essentially single energetic level. Both these soils are generally more effectively removed by anionic surfactants than was tristearin. Sodium tripolyphosphate is quite effective for removal of both soils, but combination with surfactants failed to provide the synergistic combinations found in tristearin removal. Nevertheless surfactant soil removal was improved by STP combination.     

Correlation between critical micelle concentration,fatty soil removal,and solubilization

Using two model soil-detergent systems (hard substrate/triglyceride; cotton/fat, mineral oil, graphite) it was shown that soil removal begins at, or near, critical micelle concentration (eme), confirming the work of other investigators with different systems. Maximum detergency occurs at concentrations considerably in excess of cmc, varying some 6 to 10 times cmc for different surfactants. An equation for soil removal showed excellent fit of experimental values for both detergency systems. Direct correlation between cmc, solubilization (of several materials), and soil removal was demonstrated. Marked differences between surfactant type and solubilization of triglycerides were found. The nonionic surfactants were excellent solubilizers for triolein correlating with their effective soil removal. Neither sodium oleate nor sodium tripolyphosphate effectively solubilized the triglyceride but both are effective soil removers, suggesting that their soil removal mechanism differs from the nonionics, possibly as an emulsification or displacement mechanism. Solubilization of triglyceride occurs most effectively considerably in excess of cmc.     

The temperature dependence of micellar solubilization

The temperature dependence of micellar solubilization was determined in the 180°–140°F. temperature range by using a dye solubilization technique with built and unbuilt solutions of three high-eloud point, commereial surfactants, one anionic of the alkylaryl sulphonate type and two types of nonionic agents. It was found that the logarithm of solubilization in both built and unbuilt solutions was directly proportional to temperature (solubilization was an exponential function of temperature) and that the log solubilization-temperature slopes of the built and unbuilt solutions of each surfactant were approximately parallel.     

Purification and Characterization of a Lipase from Candida curvata Lodder and Kreger — van Rij CBS 570

The purification of the lipase from Candida curvata CBS 570 was achieved steps. Its optimum pH is 6 and its optimum temperature range is Iff C to 60°C. This enzyme is thermoresistant and only loses 20% of its activity when heated at 50°C during 30 minutes. Its activation energy is 144 kcal/mole and its inactivation energy 22 kcal/mole. Its molecular weight was determined to be 195000. EDTA, p-chloromercuri benzoate, N-ethyl- and iodoacetamide have no influence on the activity of this enzyme, whereas Cu⁺⁺ and Zn⁺⁺ show strong inhibitory effects. The lipase activity is induced by the presence of triglycerides and inhibited by the presence of glucose. This enzyme strongly attacks triolein and trilinolein molecules, however it only hydrolyzes a little tristearin and trilinolenin.     

Performance and Efficiency of Anionic Dishwashing Liquids with Amphoteric and Nonionic Surfactants

Performance and efficiency of anionic [sodium lauryl ether sulfate (SLES) and sodium α-olefin sulfonate (AOS)] and amphoteric [cocamidopropyl betaine (CAB)] as well as nonionic [cocodiethanol amide (DEA), various ethoxylated alcohols (C₁₂–C₁₅–7EO, C₁₀–7EO and C₉–C₁₁–7EO) and lauramine oxide (AO)] surfactants in various dishwashing liquid mixed micelle systems have been studied at different temperatures (17.0, 23.0 and 42.0 °C). The investigated parameters were critical micelle concentration (CMC), surface tension (γ), cleaning performance and, foaming, biodegradability and irritability of anionic (SLES/AOS) and anionic/amphoteric/nonionic (SLES/AOS/CAB/AO) as well as anionic/nonionic (SLES/AOS/DEA/AO, SLES/AOS/C₁₂-C₁₅-7EO/AO, SLES/AOS/C₁₀–7EO/AO and SLES/AOS/C₉–C₁₁–7EO/AO) dishwashing surfactant mixtures. In comparison to the starting binary SLES/AOS surfactant mixture, addition of various nonionic surfactants promoted CMC and γ lowering, enhanced cleaning performance and foaming, but did not significantly affect biodegradability and irritability of dishwashing formulations. The anionic/nonionic formulation SLES/AOS/C₉–C₁₁–7EO/AO shows both the lowest CMC and γ as well as the best cleaning performance, compared to the other examined dishwashing formulations. However, the results in this study reveal that synergistic behavior of anionic/nonionic SLES/AOS/ethoxylated alcohols/AO formulations significantly improves dishwashing performance and efficiency at both low and regular dishwashing temperatures (17.0 and 42.0 °C) and lead to better application properties.     

一些阴离子／阳离子二元混合体系的增溶行为

研究了十二烷基聚氧乙烯（约含3个EO基团）硫酸三乙醇铵（TADPS）分别与十六烷基三甲基溴化铵（CTABr）、氯化十六烷基毗院（CPCI）以及氯化十二烷基吡啶（DPCI）的二元混合体系对正庚烷、正辛醇以及甲苯的饱和增溶行为。结果表明,混合体系在增溶方面的协同效应取决于增港物的极性或增港物在胶团中的位置．对增溶于胶团内核的非极性正庚烷,TAPDS／CTABr体系显示出较强的实际正协同效应,最大添加浓度（MAC）可用Nishikido的阴离子-阳离子复合物理想增港模型来预测;对既可增溶于胶团的内核,又可增溶于胶团栅栏中的微极性的甲苯,三个混合体系皆表现出实际的正协同效应;但对增溶于胶团栅栏,与表面活性剂形成混合胶团的两亲物质正辛醇,TAD－PA／CTABr体系显示出负协同效应,并且增溶物在胶团相和水相中的分布系数符合Treiner的非理想增溶模型。这些结果表明,阴离子／阳离子混合体系在胶团强化超滤（MEUF）技术中具有潜在的应用前景。     

Mixtures of anionic and cationic surfactants with single and twin head groups: Solubilization and adsolubilization of styrene and ethylcyclohexane

Mixtures of anionic and cationic surfactants with single and twin head groups were used to solubilized styrene and ethylcyclohexane into mixed micelles and adsolubilize them into mixed admicelles on silica and alumina surfaces. Two combinations of anionic and cationic surfactants were studied: (i) a single-head anionic surfactant, sodium dodecyl sulfate (SDS), with a twin-head cationic surfactant, pentamethyl-octadecyl-1,3-propane diammonium dichloride (PODD), and (ii) a twin-head anionic surfactant, sodium hexadecyl-diphenyloxide disulfonate (SHDPDS), with a single-head cationic surfactant, dodecylpyridinium chloride (DPCl). Mixtures of SDS/PODD showed solubilization synergism (increased oil solubilization capacity) when mixed at a molar ratio of 1∶3; however, the SHD-PDS/DPCl mixture at a ratio of 3∶1 did not show solubilization enhancement over SHDPDS alone. Adsolubilization studies of SDS/PODD (enriched in PODD) adsorbed on negatively charged silica and SHDPDS/DPCl adsorbed on positively charged alumina showed that while mixtures of anionic and cationic surfactants had little effect on the adsolubilization of styrene, the adsolubilization of ethylcyclohexane was greater in mixed SHPDS/DPCl systems than for SHDPDS alone. Finally, it was concluded that whereas mixing anionic and cationic surfactants with single and double head groups can improve the solubilization capacity of micelles or admicelles, the magnitude of the solubilization enhancement depends on the molecular structure of the surfactant and the ratio of anionic surfactant to cationic surfactant in the micelle or admicelle.     

Surface Properties and Solubility Enhancement of Anionic/Nonionic Surfactant Mixtures Based on Sulfonate Gemini Surfactants

As a class of novel surfactants, Gemini surfactants usually exhibit fairly excellent interfacial properties in aqueous solutions on account of the unique structure. They have significant application and development potential for industrial production. However, the mixing properties of Gemini surfactants with conventional surfactants are the key to their application. The equilibrium surface tension curves of anionic/nonionic surfactant mixtures based on the sulfonate Gemini surfactant (SGS-12) were measured using the Wilhelmy Plate method. The parameters of surface adsorption, the interaction parameters between anionic and nonionic surfactants, and the thermodynamic parameters of micelle formation were calculated from the corresponding equations. In addition, the dynamic surface tension (DST) curves of anionic/nonionic surfactant mixtures were examined through bubble profile analysis, and the diffusion performance parameters were acquired from empirical formulas. The solubilization of pyrene in micelle solutions was studied using UV–vis absorption spectroscopy. The results show that the interaction parameters of all anionic/nonionic surfactants are negative, indicating that there is a synergistic effect on reducing the surface tension. For the SGS-12/OP-10, SGS-12/Tween 80, SGS-12/AEO9, and SGS-12/APG0810 mixtures, the optimum mixing ratios are 6:4, 7:3, 7:3, and 8:2, respectively. The thermodynamic data of micelles show that the formation of mixed micelles for SGS-12/APG0810 mixtures is an enthalpy-driven process. The tendency of DST curves of the SGS-12/APG0810 mixture is similar to that of SGS-12. In comparison with single-surfactant solutions, the anionic/nonionic surfactant mixtures show stronger solubilization capacity toward pyrene.     

Correlation of hard surface detergency,soil, and surfactant

In the practical detergency range between the 90% soil removal point (the CC-1 concentration) and the point at twice the CC-1 concentration (the CC-2 point), hard surface (steel) detergency (D) is a linear function of micellar solubilization (S) such that D=K₁S+K₂, for glyceryl trioleate, oleic acid, and lauryl alcohol soils. Equations of this form were obtained for glyceryl trioleate systems using polyethenoxyethers of nonyl phenol and tridecyl alcohol, polyoxyethylene sorbitan monolaurate, sodium dodecyl benzene sulphonate, and sodium oleate. It was shown that the constants K₁ and K₂ of the detergency equation possess more than mathematical significance. Analysis of the equations for the 15, 20, and 40 ethylene oxide mole ratio adducts of nonyl phenol with glyceryl trioleate soil revealed that K₁ varied linearily with HLB of the adducts and that the K₂-log interfacial tension function (at the CC-1 point) was linear. Examination of the equations for the 20, 50, and 100 mole ratio adducts of nonyl phenol with oleic acid soil indicated also that K₁ was a function of HLB and that K₂ was a function of interfacial tension (at the CC-1 point). The detergency equations of a single surfactant (sodium dodecyl benzene sulphonate) and three soils (triolein, lauryl alcohol, and oleic acid) indicated K₁ was a function of soil dipole moment, and K₂ was a function of soil surface tension.     

Microemulsion Systems with Rhodium Tris(3-sulfophenyl)phosphine Trisodium Salt Complex for Product Isolation and Catalyst Recycling in the Hydrogenation of Dimethyl Itaconate

Microemulsion systems with the nonionic surfactant p-tert-octylphenoxy polyethoxyethanol (OP9.5EO), the anionic surfactant dioctyl sulfosuccinate sodium salt (DOSS) and the narrow range nonionic surfactant alkyl polyethylene glycol ether (C10EO5) were used as solvent systems in the catalytic hydrogenation of dimethyl itaconate (DMI) catalysed by the water soluble catalyst complex Rh-TPPTS in order to achieve product isolation and catalyst recycling. The DOSS systems, which are more sensitive to the substrate and catalyst addition allowed for the hydrogenation to proceed with an initial hydrogenation rate about three times higher than with the nonionic surfactants, when the surfactant concentration was 15 wt%. Systems with 3 wt% surfactant were used in order to accomplish catalyst recycling. With a biphasic DOSS mixture a turnover number (TON) of 1,200 mol of DMI hydrogenated per mol of catalyst (Rh) was obtained in 3 consecutive runs. A three-phase system for the OP9.5EO mixture allowed the catalyst to be recycled 3 times and a TON of 1,500 in 4 runs was obtained. A TON of 800 in 2 runs was obtained using a three-phase C10EO5 mixture.     

Surfactant interference on lipase catalysed reactions in microemulsions

The hydrolysis of palm oil with lipase as a catalyst was carried out in two different microemulsion systems. One system was based on a nonionic surfactant, pentaethylene glycol monododecyl ether (C12EO5) and the other system was based on an anionic surfactant, sodium bis(2-ethylhexyl)sulphosuccinate (AOT). The yield of free fatty acid produced by the reaction was found to be much lower in the C12EO5 system compared to the AOT system. Radiochromatography showed that the low yield was due to enzymatic esterification on the nonionic surfactant. Kinetic measurements showed that the reaction rate is about ten times faster in the AOT based microemulsion than in the nonionic system. Differences in the microemulsion structure and interfacial tensions in the two systems were found to be of no significant importance for explaining this difference. Kinetic data of mixed surfactant microemulsions indicated that the observed difference in the reaction rates of the AOT and the C12EO5 microemulsion systems was a consequence of the C12EO5 surfactant competing with the substrate for the active site of the enzyme. The reason why C12EO5 surfactant inhibited the reaction, and AOT surfactant did not, was found to be related to differences in the structures of the hydrophobic part of the surfactant.     

Selecting the optimal linear alcohol ethoxylate for enhanced oily soil removal

Use of nonionic surfactants in detergent products has become increasingly popular because of their tolerance to hardness ions and their effect on lowering the critical micelle concentration of anionics. Their performance as detergents, however, is very sensitive to changes in temperature and electrolyte concentration, which need to be carefully controlled in order to ensure that phase inversion conditions prevail. For a fixed temperature in an application, the only variables available for optimizing the performance of a system containing nonionics are: the type of nonionic, and the concentrations of electrolytes and anionics. Based on the mutual interactions of these ingredients in mixed systems, we have devised some guidelines for selection of the optimal ethylene oxide (FO) chain length in lauryl alcohol ethoxylate type of nonionics for a range of electrolytes and anionic surfactant concentrations. For any given concentration of electrolytes (sodium carbonate and sodium tripolyphosphate), anionic (sodium linear alkyl benzene sulfonate) and nonionic, the detergency of synthetic sebum from blended polyester/cotton fabrics shows a maximum as a function of average FO moles in the nonionic. Oil/water interfacial tension shows an expected reverse trend. The optimal EO moles (for maximal detergency) show a monotonically increasing trend when plotted as a function of the ratio of nonionic to anionic concentration for a fixed level of electrolyte. The optimal EO moles also increase with increasing level of electrolytes in the system. However, the effect of nonionic/anionic ratio is much stronger than the effect of electrolytes on the optimal EO moles.     

Micelle formation in mixtures of nonionic and anionic detergents

This paper describes the effect of a homologous series of polyoxyethylene n-dodecanols on the critical micelle concentration (CMC) of sodium n-dodecyl alcohol sulfate as a function of composition of the mixtures and temperature. The CMC of the nonionic component of the mixed micelles is about one-hundredth of that of the anionic. Only a gradual increase in the CMC values of the mixed micelles above the values of the nonionic components was observed in the composition range of 0–90 mole % anionic detergent. This is followed by an abrupt transition to the high CMC values of the anionic component. The gradual increase of the CMC values in the range below 90 mole % anionic detergent of n-dodecanol+ 4 EO exceeds that of the higher homologs containing 7, 23 and 30 ethylene oxide units. It is postulated that the degree of ionic repulsion of the ionic component in mixed micelles is markedly decreased as the proportion of nonionic component reaches a threshold range of 10 mole %. This effect is more pronounced with large ethylene oxide coils operating at the periphery of the micelle core than with short ethylene oxide coils. Thermodynamic data have been included.     

Radiotagged soils. Removal from several substrates and adsorption site character

Substrates investigated were glass, quartz, porcelain, steel, stainless steel, aluminum, polyethylene, methylmethacrylate, Nylon, and Teflon. Radiotagged (C-14) soils used were algal protein, stearic acid, and tristearin. Soil removal curves showed that Nylon, Teflon, methacrylate, and stainless steel had few soil-adsorption sites and that the adsorption was of an ion-exchange type. Algal protein and stearic acid soils appeared to adsorb through an ion-exchange type mechanism, with most substrates, while tristearin showed a van der Waals' type of adsorption with glass, quartz, steel, and aluminum. Conclusions as to adsorption type were based upon the shape of the soil-removal curves. Adsorption studies showed that both anionic and nonionic surfactants were adsorbed by glass, procelain, steel, and aluminum surfaces, apparently by an ion-exchange type of adsorption. The character of the surfactant adsorbed affected the degree of removal of subsequently applied soil; the more hydrophilie surfactants permitted easier soil-removal. Tripolyphosphate, orthophosphate, and ethylenediamine tetraacetate anions and tetraethylammonium cations were adsorbed by these same substrates and influenced the ease of removal of subsequently applied soil. Pretreatment of substrate by alkali generally increased the ion or surfactant adsorption more than acid-pretreated surfaces, and rather marked similarities between the adsorption sites of glass and quartz were apparent from acid pretreatment. Stearic acid soiled substrates were cleaned by a preferential displacement mechanism; the soil was rolled up into globules. Tristearin-soiled surfaces were cleaned by a similar mechanism.