bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sugar fatty acid ester surfactants: Biodegradation pathways
Authors: Baker Irene J. A. , Willing R. Ian , Furlong D. Neil , Grieser Franz , Drummond Calum J. 
Published: November 2006

AbstractIn previous work, we found that the presence of a sulfonyl or alkyl group adjacent to the ester bond of sugar ester surfactants is associated with a dramatic reduction in the rate of biodegradation relative to that of unsubstituted esters. In this study, we investigated the pathways followed during the biodegradation of sucrose laurate, sucrose α‐sulfonyl laurate, and sucrose α‐ethyl laurate to determine the reasons for their different biodegradation rates. Through the use of high‐performance liquid chromatography and proton nuclear magnetic resonance spectroscopy, the nature of the intermediates formed during the biodegradation of these three key sugar esters was determined. It was found that sucrose laurate biodegradation occurs via initial ester hydrolysis. In contrast, sucrose α‐sulfonyl laurate degrades by initial alkyl chain oxidation. This indicates that the ester hydrolysis pathway is blocked by the sulfonyl group adjacent to the ester bond so that biodegradation is forced to proceed via the slower alkyl chain oxidation pathway. Sucrose α‐ethyl laurate was degraded at least in part by alkyl chain oxidation, indicating that ester hydrolysis was also inhibited by the presence of an ethyl group. It is therefore concluded that previously observed relationships between structure and biodegradability arise because of the influence that different structural elements have on the pathways followed during biodegradation.
Multivariate quantitative structure‐activity relationships for the aquatic toxicity of technical nonionic surfactants
Authors: Uppgård Lise‐Lott , Lindgren Åsa , Sjöström Michael , Wold Svante 
Published: November 2006

AbstractThe aquatic toxicity of 36 technical nonionic surfactants (ethoxylated fatty alcohols) was examined toward two freshwater animal species, the fairy shrimp Thamnocephalus playtyurus and the rotifer Brachionus calyciflorus. Responses of the two species to the surfactants were generally similar. A multivariate‐quantitative structure‐activity relationship (M‐QSAR) model was developed from the data. The M‐QSAR model consisted of a partial least squares model with three components and explained 92.4% of the response variance and had a predictive capability of 89.1%. The most important physicochemical variables for the M‐QSAR model were the number of carbon atoms in the longest chain of the surfactant hydrophobe (redC), the molecular hydrophobicity (log P), the number of carbon atoms in the hydrophobe (C), the hydrophilic‐lipophilic balance according to Davis (Davis), the critical packing parameter with respect to whether the hydrophobe was branched or not (redCPP), and the critical micelle concentration. Surfactant toxicity tended to increase with increasing alkyl chain lengths.
Removal of cadmium or lead from polluted water by biological amphiphiles
Authors: Pekdemir Turgay , Tokunaga Shuzo , Ishigami Yutaka , Hong Kyung‐Jin 
Published: November 2006

AbstractBiological amphiphiles were examined for the removal of Cd2+ or Pb2+ from polluted water within a pH range from 2.5 to 7.5 at a fixed ratio of amphiphilic concentration to heavy metal concentration (CA/CM) on a molar basis of approximately 11. Tannic acid, among eight amphiphiles, was selected for Cd2+ or Pb2+ removal because it exerted noticeable improvement within limited pH ranges. In the presence of tannic acid, the removal of Cd2+ or Pb2+ was investigated as a function of pH ranging from 2.5 to 13 at CA/CM ratios from 1.2 to 11. The removal capacity (mass of metal/mass of tannic acid) increased with decreasing CA/CM for both Cd2+ and Pb2+. Removal capacities were 0.084 and 0.154 g/g‐tannic acid for Cd2+ and Pb2+ at pH 6.9 and 4.4, respectively. The maximal removals for Cd2+ and Pb2+ were 99 and 96%, respectively.
Prediction of critical micelle concentration of some anionic surfactants using multiple regression techniques: A quantitative structure‐activity relationship study
Authors: Jalali‐Heravi M. , Konouz E. 
Published: November 2006

AbstractComputer‐assisted methods were employed to develop a statistical relationship between molecular‐based structural parameters and log critical micelle concentration (CMC) of some anionic surfactants. The CMC of 31 alkyl sulfates and alkanesulfonates were used for model generation. Among different models, two equations were selected as the best, and their specifications are given. The statistics of these models together with cross‐validation results indicate the capability of both models to predict the CMC of anionic surfactants. Three descriptors of Wiener number, reciprocal of the dipole moment, and reciprocal of the Randic index appear in the models. Results indicate that topological characteristics, such as compactness and branching of anionic surfactants, play major roles in micelle formation. Polarity of the molecules is also important, but its effect is less than that of topology of the surfactants.
On the measurement of critical micelle concentrations of pure and technical‐grade nonionic surfactants
Authors: Patist A. , Bhagwat S. S. , Penfield K. W. , Aikens P. , Shah D. O. 
Published: November 2006

AbstractThe critical micelle concentrations (CMC) of nine commercial nonionic surfactants (Tween 20, 22, 40, 60, and 80; Triton X‐100; Brij 35, 58, and 78) and two pure nonionics [C12(EO)5 and C12(EO)8] were determined by surface tension and dye micellization methods. Commercially available nonionic surfactants (technical grade) usually contain impurities and have a broad molecular weight distribution owing to the degree of ethoxylation. It was shown that the surface tension method (Wilhelmy plate) is very sensitive to the presence of impurities. Much lower CMC values were obtained with the surface tension method than with the dye micellization method (up to 6.5 times for Tween 22). In the presence of highly surfaceactive impurities, the air/liquid interface is already saturated at concentrations well below the true CMC, leading to a wrong interpretation of the break in the curve of surface tension (γ) vs. concentration of nonionic surfactant (log C). The actual onset of micellization happens at higher concentrations, as measured by the dye micellization method. Furthermore, it was shown that when a commercial surfactant sample (Tween 20) is subjected to foam fractionation, thereby removing species with higher surface activity, the sample yields almost the same CMC values as measured by surface tension and dye micellization methods. It was found that for monodisperse pure nonionic surfactants, both CMC determination methods yield the same results. Therefore, this study indicates that precaution should be taken when determining the CMC of commercial nonionic surfactants by the surface tension method, as it indicates the surface concentration of all surface‐active species at the surface only, whereas the dye method indicates the presence of micelles in the bulk solution.
Synthesis and surface properties of chemodegradable anionic surfactants: Diastereomeric (2‐n‐alkyl‐1,3‐dioxan‐5‐yl) sulfates with monovalent counter‐ions
Authors: Piasecki Andrzej , Mayhew Alexandra 
Published: November 2006

AbstractSodium, potassium and ammonium cis‐ and trans‐(2‐n‐alkyl‐1,3‐dioxan‐5‐yl) sulfates 6–8 (alkyl: n‐C9H19, 6a–8a, and n‐C11H23, 6b–8b) were synthesized in a reaction of aliphatic aldehydes 1a,b with glycerol 2 followed by separation in high yields of individual geometric isomers of cis‐and trans‐2‐n‐alkyl‐5‐hydroxy‐1,3‐dioxanes, cis‐3a,b and trans‐3a,b, followed by sulfation with sulfur trioxide‐pyridine complex, and finally neutralization with NaOH, KOH, and NH4OH, respectively. Physical data of the compounds and some surface properties of 2‐n‐nonyl derivatives, such as critical micelle concentration (CMC), effectiveness of aqueous surface tension reduction (ΠCMC), surface excess concentration ΓCMC, and the surface area demand per molecule (ACMC), were determined. It was shown that the surface activity of these compounds is influenced both by their geometric structure and by the monovalent counter‐ion.
Comparison of analyses of surfactants in cosmetics using high‐performance liquid chromatography and high‐performance capillary electrophoresis
Authors: Lin Wen‐Chung , Lin Shaw‐Tao , Shu Shwu‐Ling 
Published: November 2006

AbstractSeparation of anionic, cationic, and amphoteric surfactants containing n‐dodecyl groups and hydrophilic moieties was done by high‐performance liquid chromatography (HPLC) and high‐performance capillary electrophoresis (HPCE), and an ultraviolet‐visible detector. Quantitation of surfactants in commercial cosmetic and toiletry products was also done using similar methods. Conditions used to separate mixtures of surfactants by HPLC are as follows: stationary phase: ODS 2; mobile phase: MeOH/H2O (80∶20, vol/vol) containing 1.0M NH4Cl, 0.003 M tetrabutylammonium hydrogen sulfate, and 0.005 M diammonium phosphate buffer solution at pH=6.0. Conditions for HPCE are as follows: an uncoated capillary (100 μm i.d., 110 cm in length, effective length of 75 cm) with 25 kV of applied voltage, and an aqueous buffer containing 80 mM sodium borate/20 mM NaOH at pH=9.2. Surfactants were eluted within 15 min. The accuracy of both techniques was evaluated by analyzing the recovery ratio of surfactants in the mixture.
Cleavable surfactants
Authors: Hellberg Per‐Erik , Bergström Karin , Holmberg Krister 
Published: November 2006

AbstractCleavable surfactants are of interest for several reasons. Above all, the development of surfactants with weak bonds deliberately built into the structure is driven by the need for improved biodegradability of amphiphiles. The breakdown may be catalyzed by enzymes, and biodegradation would be the normal mechanism in sewage plants. Alternatively, the surfactant may degrade by chemical means, e.g., induced by acid, alkali, ultraviolet (UV) light, heat, or ozone. Acid‐ and alkali‐labile surfactants have attracted particular attention, and there is often a compromise between required stability at one stage and ease of breakdown at a subsequent stage. The paper reviews the main routes used to prepare cleavable surfactants and points out advantages and disadvantages of the different approaches. Emphasis is placed on the development during recent years. Cyclic and acyclic acetals, ketals, and ortho esters are the most important types of bonds for the preparation of acid‐labile surfactants, whereas alkali‐labile amphiphiles usually are based on ester bonds. The ester bond approach has been particularly important for cationic surfactants, and so‐called ester quats have rapidly taken a large share of the traditional market for quats. Betaine esters constitute a special class of ester with very pronounced pH dependence. UV‐labile surfactants based, for instance, on an azo bond, offer promise for the future.
Impact of molecular structure on the performance of methyl ester ethoxylates
Authors: Cox Michael F. , Weerasooriya Upali 
Published: November 2006

AbstractMethyl ester ethoxylates are a new class of ethylene oxide (EO)‐derived surfactants. Little is known about the impact of structural variations on their performance properties. The effects of carbon chain length, EO content, the degree of unsaturation of the methyl ester feedstock, and feedstock purity were examined for their impact on both physical properties and surfactant performance properties. Physical properties examined included surface properties (surface tension, critical micelle concentration, surface excess adsorption), melting point, water solubility, viscosity, foam stability, color, clarity, and odor. The impact of molecular structure on performance was examined for various applications, including laundry detergents, dishwashing detergents, and hard‐surface cleaners.
Synthesis, physicochemical properties, and detergency of disodium 2‐alkyl‐1,3‐propanediyl bissulfates
Authors: Kooreman P. A. , Engberts J. B. F. N. , van Os N. M. 
Published: November 2006

AbstractIn this paper we describe the synthesis and the physicochemical properties of a series of highly calcium‐tolerant anionic surfactants. Detergency tests for one of the surfactants, disodium 2‐n‐hexadecyl‐1,3‐propanediyl bissulfate 3d, in formulations with and without builder are reported. These tests were performed using a robot‐Terg‐O‐tometer. The results of these tests are compared to the results of detergency tests of standard surfactants: LAS 113, a linear alkylbenzenesulfonate, PAS 45, a linear alkylsulfate, and PAES 23‐2S, an alkylethersulfate, representing standard commercial anionic surfactants of which the last is calcium‐tolerant, i.e., it does not precipitate from its aqueous solution in the presence of calcium ions. The detergency performance of bissulfate 3d was similar to that of PAES 23‐2S, with and without builder.
New coupling method without heavy metals for the synthesis of a new class of fatty acid methyl ester oligoglycoside ethers
Authors: Bogaert P. M. P. , Bakker F. K. G. , Slaghek T. M. , de Wit D. , Van der Meeren P. 
Published: November 2006

AbstractA new method, using poly‐O‐acetyl‐β‐d‐glycopyranosylbromide, methyl 9‐or methyl 12‐hydroxyoctadecanoate and triethylamine as catalyst, is described for the synthesis of a new class of nonionic surfactants. Chemical structures were identified using 1H and 13C nuclear magnetic resonance spectroscopy including two‐dimensional techniques and Fourier transforming infrared. Critical micelle concentrations and surface tension profiles of these O‐alkyl‐β‐d‐glycosides in water were determined.
Applications of protecting groups in the synthesis of surfactants, lipids, and related compounds
Authors: Urata Kouichi , Takaishi Naotake 
Published: November 2006

AbstractSeveral types of alkyl ether lipids were prepared in high yield and high purity using protecting groups such as 1,3‐dioxolane compounds or allyl ethers. We also succeeded in the industrial production of alkyl glyceryl ethers using the reaction of alkyl glycidyl ethers with acetone to give 1,3‐dioxolane compounds, from which the desired alkyl glyceryl ethers were obtained in high quantities. 1,3‐Dioxolane (ketal) compounds based on acetone were used in the enzymatic preparation of monoglyceride on an industrial scale. On the basis of these protecting groups, we extended our studies concerning both the preparations and properties of novel polyol ether compounds, beginning with alkyl glycidyl ethers. Another typical property of surfactants containing 1,3‐dioxolane units and acetal is degradability under acidic conditions. Several types of destructible/cleavable surfactants based on polyols, such as carbohydrates and polyethyleneglycol, were prepared. As for natural products containing polyol skeletons, much attention has been paid to their molecular design, in which protecting groups such as 1,3‐dioxolane compounds or allyl ether have contributed to synthetic strategies.
Regioselective synthesis of dimeric (gemini) and trimeric sugar‐based surfactants
Authors: Gao Chunli , Millqvist‐Fureby Anna , Whitcombe Michael J. , Vulfson Evgeny N. 
Published: November 2006

AbstractA simple and flexible chemoenzymatic route for the preparation of a wide range of dimeric (gemini) and trimeric mono‐ and disaccharide‐based surfactants was developed. The synthesis relies on the use of enzymes for regioselective introduction of fatty acids into carbohydrate moieties. Several structures were prepared containing xylose, glucose, galactose, and lactose, connected via different hydroxyl groups in the sugar molecules or, alternatively, via the OH group of 2‐hydroxytet‐radecanoic acid used as a hydrophobic moiety for the surfactant.
Interfacial mass transfer vs. Formulation in multiple phase anionic surfactant‐oil‐water systems
Authors: Fillous Lauriane , Cardenas Antonio , Rouivere Jacques , Salager Jean‐Louis 
Published: November 2006

AbstractMass transfer through a liquid membrane was studied in a macroscopic setup that allowed an estimate of the resistance to interface crossing. It was found that the interfacial transfer was associated with the phase behavior and physicochemical formulation of the surfactant‐oil‐water system. The resistance to interfacial mass transfer closely followed the variation of interfacial tension, i.e., it was minimal at the optimal formulation of the so‐called Winsor III phase behavior systems.
Improvement on acid pyrolysis method for alkyl homolog and phenyl isomer distribution of alkylbenzene sulfonates
Authors: Uchiyama Toshihiko , Kawauchi Akihiko 
Published: November 2006

AbstractAn acid pyrolysis method developed by H.L. Lew in 1967 has been further investigated and improved. Alkylbenzene sulfonates are pyrolyzed with phosphoric acid. This gives quantitative desulfonation. The resulting alkylbenzenes are online analyzed by gas chromatography. Lew's approach replaced the time‐consuming reflux desulfonation gas chromatography methodology. While greatly reducing turnaround time, phosphoric acid used for acid pyrolysis in Lew's method resulted in deterioration of the gas chromatography column stationary phase and also corrosion of the pyrolysis tube. Improvement in these areas was studied. Column deterioration can be eliminated by using an acid trap, and pyrolysis tube corrosion can be minimized by using quartz wool to prevent phosphoric acid sputtering in the pyrolyzer. The method discussed in this paper produces results totally comparable with the reflux desulfonation gas chromatography and Lew's methods.
Surface properties of N‐alkanoyl‐N‐methyl glucamines and related materials
Authors: Zhu Yun‐Peng , Rosen Milton J. , Vinson Phillip K. , Morrall Stephen W. 
Published: November 2006

AbstractThe surface properties [effectiveness of surface tension reduction (γCMC) critical micelle concentration (CMC), efficiency of surface tension reduction (pC20), maximal surface excess concentration (Γmax), minimal area/molecule at the interface (Amin), and the (CMC/C20) ratio] of some well‐purified N‐alkanoyl‐N‐methyl glucamines and related polyol‐based N‐methyl amide‐type surfactants, having the structural formula RC(O)N(Me)CH2(CHOH)xCH2OH, where RC(O)=undecanoyl, lauroyl, tridecanoyl, myristoyl, and x=1,3, and 4, were investigated at 25°C in distilled water and 0.1 M NaCl. Water solubility of these compounds does not simply depend on the number of hydroxyl groups in the molecule but is associated with the balance between intermolecular hydrogen bonds and hydrogen bonds formed with water molecules. The fundamental interfacial properties, such as CMC and γCMC and two thermodynamic parameters, standard free energy of adsorption and standard free energy of micellization, were found to be significantly dependent on the hydrophobic acyl chain rather than on the number of CHOH groups in the hydrophilic moieties. By contrast, the practical performance properties were greatly dependent on the nature of the hydrophilic group. As a whole, these surfactants had desirable foaming properties and efficient wetting abilities. Furthermore, synergism in foaming and wetting abilities was observed in a binary mixture of these surfactants with an alkyloxyethylene sulfate.
Ester alkoxylation technology
Authors: Weerasooriya Upali 
Published: November 2006

AbstractConventional ethyoxylation technologies, when used on fatty methyl esters, produce poor yields as well as flat ethoxymer distributions. Peaking ethoxylation catalysts have been successful in efficient conversion of methyl esters into the ethoxylates possessing peaked ethoxymer distribution. Surfactant performance of methyl ester ethoxylates was evaluated. Results generally show these to behave similarly to alcohol ethoxylates, with the exception of exhibiting a lower foam profile. This ester ethoxylation technology has been successful in ethoxylating esters of varying steric environments. Triglyceride ethoxylates have been partially saponified as well as glucaminolyzed to produce mild surfactant blends.
Genetics of obesity: More complicated than initially thought
Authors: Shuldiner Alan R. , Munir Kashif M. 
Published: November 2006

AbstractDuring the past several decades, there has been an explosion in the prevalence of obesity. Since our genes have not changed appreciably during that time, it stands to reason that the present epidemic is caused by our pervasive obesigenic environment, in which excess caloric intake and decreased physical activity conspire with one another. Despite an obesigenic environment, humans have great variability in their susceptibility to obesity, which is determined in large part by genetics. Current evidence suggests that genetic susceptibility to human obesity is the result of multiple genes, each with a modest effect, that interact with each other and with environmental provocations. Elucidation of obesity susceptibility genes through genome‐wide and candidate gene approaches provides great promise in ultimately determining the genetic underpinnings of obesity. Further research will translate these new insights on the pathophysiological basis of obesity into new medications and diagnostic tests.
Sedentary lifestyle and risk of obesity and type 2 diabetes
Authors: Hu Frank B. 
Published: November 2006

AbstractObesity and type 2 diabetes have reached epidemic proportions in the United States. It is well‐established that increasing physical activity plays an important role in reducing rick of obesity and diabetes. Few studies, however, have examined the association between sedentary behaviors such as prolonged television (TV) watching and obesity and diabetes. Using data from a large prospective cohort study, the Health Professionals’ Follow‐up Study, we have demonstrated that increasing TV watching is strongly associated with obesity and weight gain, independent of diet and exercise. Also, prolonged TV watching is associated with a significantly increased risk of type 2 diabetes. Men who watched TV more than 40 h per week had a nearly threefold increase in the risk of type 2 diabetes compared with those who spent less than 1 h per week watching TV. The increased risk was not entirely explained by the decreased physical activity and unhealthy eating patterns associated with TV watching. Thus, public health campaigns to reduce the risk of obesity and type 2 diabetes should promote not only increasing exercise levels but also decreasing sedentary behaviors, especially prolonged TV watching.
The role of energy density
Authors: Drewnowski Adam 
Published: November 2006

AbstractDietary energy density (ED) appears to have a major influence on the regulation of food intake and body weight. If people consume a fixed weight of food each day, then high‐ED diets should be associated with high energy intakes and with overweight. In contrast, low‐ED diets should result in lower daily energy intakes and therefore weight loss. For this approach to work, low‐ED foods must be as palatable as high‐ED foods and, calorie for calorie, have a greater satiating power. Each of those assumptions is debatable. Dietary ED depends chiefly on the water content of foods. As a rule, high‐ED foods are more palatable but less satiating, whereas low‐ED foods are more satiating but less palatable. Consumer preferences for high‐ED foods can be explained in terms of good taste, low cost, and convenience. Low‐ED foods, such as fresh produce, provide less energy per unit cost than do high‐ED foods, which often contain added sugars and fats. Poverty and obesity may well be linked through the habitual consumption of a low‐cost, high‐ED diet.