Green surfactants

Mesnager J, Quettier C, Lambin A, Rataboul F, Perrard A, Pinel C (2010) Telomerization of butadiene with starch in water role of the surfactants. Green Chem 12 475-482... 

Fig. 3. A oscillations of the interfacial tension between DCM and an aqueous solution containing 5mM CTAB. Inset shows the oscillations between 6850-7800 sec in detail. The line in the inset indicates the time when movements at the interface were initiated. B Schematic representation of the processes leading to oscillations in the biphasic system (details see text). Dashed line represents the normal to the interface concentration gradient of the surfactant, green triangle stands for the initial fluctuation, red arrows represent Marangoni flows and the curved arrows represent the convective cells induced by the Marangoni instability (Colour figure online)...

P6rez, N., Perez, L., Infante, M. R. and Garda, M. T. (2005) Biological properties of arginine-based glycerolipidic cationic surfactants. Green Chem., 1, 540-546. 

Mordn, M. C., Pinazo, A., P6rez, L. et al. (2004b) Green amino acid-based surfactants. Green Chem., 6, 233-240. 

In this work hybrid method is suggested to determine anionic surfactants in waters. It is based on preconcentration of anionic surfactants as their ion associates with cationic dyes on the membrane filter and measurement of colour intensity by solid-phase spectrophotometry method. Effect of different basic dyes, nature and hydrophobicity of anionic surfactants, size of membrane filter pores, filtration rate on sensitivity of their determination was studied. Various cationic dyes, such as Methylene Blue, Crystal Violet, Malachite Green, Rhodamine 6G, Safranin T, Acridine Yellow were used as counter ions. The difference in reflection between the blank and the sample was significant when Crystal Violet or Rhodamine 6G or Acridine Yellow were used. 

The ionic associates of malachite green cation with dodecyl sulfate anion has been suggested for monitoring nonionic surfactant levels in industrial wastewaters by spectrophotometric determination at 650 nm [196]. 

Both approaches are useful and they are also complementary because it is important to know where a chemical that may be best in its class falls out with respect to hazard. For example, a surfactant that is best in its class will be rapidly biodegradable, but most surfactants have some aquatic toxicity because they are surface active. However, surfactants as a class are typically close to the green end of the hazard spectrum because they tend to have low hazard ratings for most other endpoints. It is also possible to have chemicals that are best in their class but that are still problematic. For example, some dioxin congeners are less toxic than others but one would not presume that a dioxin congener that is best in its class is green . Concurrent use of the best in class approach with the absence of hazard approach is also important because it drives continual advancement within a class toward the ideal green chemistry. Once innovation occurs and a chemical or product is developed that meets the same or better performance criteria with lower hazard, what was once considered best in class shifts. 

Green FHY, Schurch S, De Sanctis GT, et al. 1991. Effects of hydrogen sulfide exposure on surface properties of lung surfactant. J Appl Physiol 70 1943-1949. 

In conclusion, the yellow contamination appears to be a mixture of materials, their infrared spectra suggesting that they are primarily a vegetable oil and pullulan, with possibly a surfactant and maybe an inorganic pigment also being present. The green residue is consistent with a saturated aliphatic hydrocarbon, such as a processing aid or an oil. 

Meso- and (+ )-azobis[6-(6-cyanododecanoic acid)] were synthesized by Porter et al. (1983) as an amphipathic free radical initiator that could deliver the radical center to a bilayer structure controllably for the study of free radical processes in membranes. The decomposition pathways of the diazenes are illustrated in Fig. 36. When the initiator was decomposed in a DPPC multilamellar vesicle matrix, the diazenes showed stereo-retention yielding unprecedented diastereomeric excesses, as high as 70%, in the recombination of the radicals to form meso- and (+ )-succinodinitriles (Brittain et al., 1984). When the methyl esters of the diazene surfactants were decomposed in a chlorobenzene solution, poor diastereoselectivity was observed, diastereomeric excesses of 2.6% and 7.4% for meso- and ( )-isomers respectively, which is typical of free radical processes in isotropic media (Greene et al, 1970). 

Recently, an example of green chemistry in the formation of a nitrone in aqueous medium, using a surfactant, was reported in 1,3-dipolar cycloadditions to ethyl acrylate (776). The control of regioselectivity in this reaction favors the formation of trans -5-substituted isoxazolidines. 

Lewis acids as water-stable catalysts have been developed. Metal salts, such as rare earth metal triflates, can be used in aldol reactions of aldehydes with silyl enolates in aqueous media. These salts can be recovered after the reactions and reused. Furthermore, surfactant-aided Lewis acid catalysis, which can be used for aldol reactions in water without using any organic solvents, has been also developed. These reaction systems have been applied successfully to catalytic asymmetric aldol reactions in aqueous media. In addition, the surfactant-aided Lewis acid catalysis for Mannich-type reactions in water has been disclosed. These investigations are expected to contribute to the decrease of the use of harmful organic solvents in chemical processes, leading to environmentally friendly green chemistry. 

Plate 4 (Figure 8, Chapter 2, p. 46). Typical snapshot of DPD simulation results [64]. The hydrophobic part of mixed bilayers of DPPC-like lipids and up to 0.8 mole-fraction of the nonion surfactant C12E6 (left) and 0.9 (right). The surfactant C12 chains are represented by green curves, the lipid C15 chains are black. The hole in the left conformation is transient, at the right they are stable. Reproduced by permission of the Biophysical Society... 

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