- Aggregation and thermodynamic properties of some cationic gemini surfactants
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In this study, the gemini surfactants of the alkanediyl-α-ω- bis(alkyl dimethyl ammonium) dibromide type, on the one hand, with different alkyl groups containing m carbon atoms and an ethanediyl spacer, referred to as ''m-2-m'' (m = 10, 12 and 16) and, on
- Akbas, Halide,Elemenli, Aylin,Boz, Mesut
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- Surface-active properties and antimicrobial study of conventional cationic and synthesized symmetrical gemini surfactants
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Symmetrical gemini surfactants of cationic series α,ω- alkanediyl bis (dimethyl ammonium bromide) commonly referred as ''m-s-m'' have been synthesized. Spectral analysis was performed to confirm compound structures and purity. Conductivity and surface tension measurements provide better understanding of the micellization process. Their self-assembly behavior in aqueous solution is also discussed in detail. The antimicrobial efficacy was measured by bacterial and fungal growth inhibition expressed as minimal inhibitory concentration values against five strains of a representative group of microorganisms viz. Bacillus subtilis, Staphylococcus aureus, Klebsiella pneumonia, Salmonella paratyphi B and Aspergillus niger. All of the synthesized surfactants showed antimicrobial activity against them, but at different levels depending on their structures. The surfactants possessing longer alkyl chains (more hydrophobic environment) demonstrated better antimicrobial functionality. The antimicrobial potency was found to be dependent on the representative target microorganism (Gram-positive bacteria > fungi >Gram-negative bacteria), as well as on the ionic nature of the surfactant (cationic), alkyl chain length (m = 12, 16) and spacer length (s = 2, 4, 6) of the synthesized compounds. Gemini surfactants such as 12-2-12 and 12-4-12 were found to be weakly active whereas 16-2- 16 and 16-4-16 compounds proved to be the most potent antimicrobial surface-active agents among the synthesized gemini homologues. AOCS 2011.
- Kuperkar, Ketan,Modi, Jigisha,Patel, Keshav
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- Synthesis, molecular structure, spectral properties and antifungal activity of polymethylene-α,ω-bis(n,n-dimethyl-n-dodecyloammonium bromides)
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Hexamethylene-1,6-bis-(N,N-dimethyl-N-dodecylammonium bromide) (1), pentamethylene-1,5-bis(N,N-dimethyl-N-dodecylammonium bromide) (2), tetramethylene-1,4-bis(N,N-dimethyl-N-dodecylammonium bromide) (3), trimethylene-1,3-bis(N,N-dimethyl-N-dodecylammonium bromide) (4) and ethylene-1,2-bis(N,N-dimethyl-N-dodecylammonium bromide) (5) have been obtained and characterized by FTIR and NMR spectroscopy. DFT calculations have also been carried out. The optimized bond lengths, bond angles and torsion angles calculated by Hartree-Fock/3-21G(d,p) approach have been presented. MIC values for A. niger, P. chrysogenum, C. albicans have been determined and the relationship between MIC and spacer length has been discussed.
- Brycki, Bogumil,Kowalczyk, Iwona,Kozirog, Anna
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- Gemini surfactant electrospun membranes
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Our research demonstrates electrospun nonwoven fibrous scaffolds from a low molar mass gemini ammonium surfactant, N,N'-didodecyl-N,N,N',N'-tetramethyl-N, N'-ethanediyldiammonium dibromide (12-2-12). Cryogenic transmission electron microscopy (cryo-TEM) and solution rheological experiments revealed micellar morphological transitions of 12-2-12 in water and watenmethanol (1:1 vol). The microstructure of 12-2-12 in water transitioned from entangled, cylindrical, threadlike micelles to branched threadlike micelles, and a viscoelastic, entangled, highly branched network of threadlike micelles with increasing concentration finally formed. In sharp contrast, the solution behavior of 12-2-12 in watenmethanol produced a drastically different micellar microstructure compared to that in water, and the morphology transitioned from partitioned, globular micelles to overlapped micelles at an overlap concentration (C*) of 11 wt %. Electrospinning 12-2-12 from water did not produce fibers at any concentration; however, electrospinning 122-12 in watenmethanol at concentrations greater than 2C* produced hydrophilic continuous fibers with diameters ranging from 0.9 to 7 μm. High surface area scaffolds with hydrophilic surfaces offer potential as charged controlledrelease membranes, tissue engineering scaffolds, and coatings for biologically compatible devices.
- Cashion, Matthew P.,Li, Xiaolin,Geng, Yan,Hunley, Matthew T.,Long, Timothy E.
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- Nonaqueous lyotropic liquid-crystalline phases formed by gemini surfactants in a protic ionic liquid
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The aggregation behaviors of three Gemini surfactants [(CsH 2s-α,ω-(Me2N+CmH 2m+1Br-)2, s = 2, m = 10, 12, 14] in a protic ionic liquid, ethylammonium nitrate (EAN), have been investigated. The polarized optical microscopy and small-angle X-ray scattering (SAXS) measurements are used to explore the lyotropic liquid crystal (LLC) formation. Compared to the LLCs formed in aqueous environment, the normal hexagonal and lamellar phases disappear. However, with increasing the surfactant concentration, a new reverse hexagonal phase (HII) can be mapped over a large temperature range except for other ordered aggregates including the isotropic solution phase and a two-phase coexistence region. The structural parameters of the HII are calculated from the corresponding SAXS patterns, showing the influence of surfactant amount, alkyl chain length, and temperature. Meanwhile, the rheological profiles indicate a typical Maxwell behavior of the LLC phases formed in EAN.
- Wang, Xudong,Chen, Xiao,Zhao, Yurong,Yue, Xiu,Li, Qiuhong,Li, Zhihong
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- Micellization studies of dicationic gemini surfactants (m-2-m Type) in the presence of various counter- and Co-ions
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Salts have the ability to influence the water activity and self-association of ionic micelles. In the present case, gemini surfactants; ethanediyl-α,ω-bis(dimethyl alkyl ammonium bromide) (referred to as m-2-m, m = 10, 12, 14) are synthesized and their micellization study in aqueous medium in presence of monovalent inorganic (NaBr, NaNO3, NaCl, KCl, LiCl) and organic salts (NaTos, NaBenz, NaSal) at 303 K is systematically investigated by conductometric and tensiometric methods. All the salts have the tendency to lower the critical micelle concentration of the surfactants. The effect of inorganic salts on the micellization properties has been found to obey the Hofmeister series. Organic salts reduce the CMC more effectively as compared to inorganic salts. The theoretical models of Rubingh and Rosen have been used to compare the results and obtain the interaction parameters, minimum area per molecule, surface excess, mixed micelle composition, activity coefficients and free energies of micellization/adsorption.
- Aslam, Jeenat,Siddiqui, Umme Salma,Ansari, Wajid Husain,Kabir-Ud-Din
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- Phase Transfer Catalysis with Quaternary Ammonium Type Gemini Surfactants: O-Alkylation of Isovanillin
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In this paper, O-alkylation of isovanillin with unusual phase transfer catalysts alkandiyl-α,ω-bis(dimethylalkylammonium bromide) dimeric surfactants (also known as gemini surfactants) is described. Some dimeric surfactants with simple hydrophobic alkyl chains and others with hydrophobic alkyl chains containing ester functionalities with different lengths were synthesized and characterized in our laboratory. The alkylation of isovanillin with alkyl halide was successively carried out in the presence of potassium carbonate and a phase transfer catalyst in tetrahydrofuran. The same reactions were also performed with both the traditional phase transfer catalyst tetrabutylammonium bromide and without any catalyst. The results were compared with those of dimeric surfactants. Consequently, it was expressed that alkandiyl-α,ω-bis(dimethylalkylammonium bromide) dimeric surfactants successively exhibit the character of phase transfer catalysts through environmentally friendly procedures under mild conditions. The most significant feature of this work is that dimeric surfactants have been determined to act as phase transfer agents.
- Boz, Mesut,Ba?türk, Sedat Semih
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- Adsorption of cationic gemini surfactants at solid surfaces studied by QCM-D and SPR: Effect of the rigidity of the spacer
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Two small series of cationic gemini surfactants with dodecyl tails have been synthesized and evaluated with respect to self-assembly in bulk water and at different solid surfaces. The first series contained a flexible alkane spacer and is denoted 12-n-12,
- Mivehi, Leila,Bordes, Romain,Holmberg, Krister
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- Tuning the surface activity of gemini amphiphile by the host-guest interaction of cucurbit[7]uril
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This research is aimed to develop an effective supramolecular route for tuning the surface activity of the surfactant. To this end, cationic gemini amphiphiles and cucurbit[7]uril (CB[7]) were complexed in water, and each hydrophobic chain of the gemini amphiphiles was bound with a CB[7]. The steric hindrance of CB[7] prevented the two hydrophobic chains from getting closed to each other, leading a significant change of surface activity. Before supramolecular complexation, the surface activity of the gemini amphiphile is relatively high, which can generate the foams easily. However, the foam generated by gemini amphiphile can be destructed by adding CB[7], suggesting that the suface activity is lowed after the supramolecular complexation. The surface activity can recover after adding 1-adamantanamine hydrochloride, which has a stronger ability to bind CB[7]. Therefore, a controllable foaming and defoaming process can be realized. It is highly anticipated that supramolecular chemistry for tuning amphiphilicity of surfactants may find application in the fields that fast foaming and defoaming are needed.
- Wang, Guangtong,Kang, Yuetong,Tang, Bohan,Zhang, Xi
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- A relative study on the micellization behavior of 12–2–12 Gemini surfactant with lactose and maltodextrin in aqueous medium: Spectroscopic and conductometric analysis
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The present work reports the micellization mechanism and physico–chemical properties of synthesized 12–2–12 Gemini surfactant in aqueous solution of carbohydrates (lactose and maltodextrin) (0.0, 0.5, 1.0) % (w/v) at varying temperatures in the range (293.15–313.15) K. For this purpose, conductometric as well as spectroscopic measurements have been engaged to analyze the micellar modulation of Gemini surfactant in terms of its critical micelle concentration (CMC). The carbohydrates (lactose/maltodextrin) have been found to decrease the CMC of 12-2-12 Gemini surfactant, however, the effect is much more pronounced in maltodextrin as compared to lactose which is in compliance with the hydrophobic region present in the molecules. Further, temperature dependence of CMC has been employed to compute thermodynamic parameters of micellization in order to procure a better knowledge about the behavior of surfactant and intermolecular interactions present in such systems. The study of aqueous Gemini–carbohydrate systems may be helpful in working towards a healthier world from both personal as well as environmental aspects of life.
- Chauhan,Atika,Singh, Kailash,Singh, Kuldeep,Kaur, Maninder,Chauhan
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- Adsorption characteristics of monomeric/gemini surfactant mixtures at the silica/aqueous solution interface
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The adsorption of the monomeric/gemini surfactant mixtures at the silica/aqueous solution interface has been characterized on the basis of quartz crystal microbalance with dissipation monitoring (QCM-D) and atomic force microscopy (AFM) data. The gemini surfactant employed in this study was cationic 1,2-bis(dodecyldimethylammonio)ethane dibromide (12-2-12). This surfactant was mixed with monomeric surfactants (dodecyltrimethylammonium bromide (DTAB), hexadecyltrimethylammonium bromide (HTAB), and octaoxyethylenedodecyl ether (C12EO8)) in the presence of an added electrolyte (NaBr). The key finding in our current study is that the addition of the gemini surfactant (12-2-12) makes significant impact on the adsorption properties even when the mole fraction of 12-2-12 is quite low in the surfactant mixtures. This is suggested by the experimental results that (i) the QCM-D adsorption isotherms measured for the monomeric/gemini surfactant mixtures shift to the region of lower surfactant concentrations compared with the monomeric single systems; (ii) the adsorbed layer morphology largely depends on the mole fraction of 12-2-12 in the surfactant mixtures, and the increased 12-2-12 mole fraction results in the less curved surface aggregates; and (iii) the addition of 12-2-12 yields a relatively rigid adsorbed layer when compared with the layer formed by the monomeric single systems. These adsorption properties result from the fact that the more favorable interaction of 12-2-12 with the silica surface sites drives the overall surfactant adsorption in these mixtures, which is particularly obvious in the region of low surfactant concentrations and at the 12-2-12 low mole fractions. We believe that this knowledge should be important when considering the formulation of gemini surfactants into various chemical products.
- Sakai, Kenichi,Matsuhashi, Kazunori,Honya, Ayako,Oguchi, Takakuni,Sakai, Hideki,Abe, Masahiko
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- Study on cloud points of Triton X-100-cationic gemini surfactants mixtures: A spectroscopic approach
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This study investigates the effects of various cationic surfactants on the cloud point (CP) of the nonionic surfactant Triton X-100 (TX-100) in aqueous solutions. Instead of visual observation, a spectrophotometer was used for measurement of the cloud point temperatures. The values of CPs for Triton X-100 can be measured directly because TX-100 has an average number of oxyethylene units per molecule of p ≈ 9.5 and a CP = 66.0 °C. Quaternary ammonium dimeric surfactants (m-s-m, m = 10, 12, and 16, and s = 2, 6, and 10) were synthesized and used. The melting temperature TM and the Krafft temperature TK were measured for 1 wt% aqueous solutions of these synthesized surfactants. The melting temperature of the solid gemini surfactants increased with the carbon number of the alkyl chain. The results showed that additions of the gemini surfactants (which are infinitely miscible with water) to Triton X-100 increased the cloud point of the TX-100 solutions. All salts tested in these studies had a large effect on the CPs of nonionic surfactants due to their effect on water structure and their hydrophilicity. The effect of the alkyl chain length of the gemini surfactant on the CP of Triton X-100 is therefore more important than the spacer chain length.
- Akbas, Halide,Boz, Mesut,Batigoec, Cigdem
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- TMEDA-derived biscationic amphiphiles: An economical preparation of potent antibacterial agents Dedicated to Professor Amos B. Smith, III, in celebration of his 40 years of mentoring scientists
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Bis-alkylated derivatives of N,N,N′,N′- tetramethylethylenediamine (TMEDA) represent a well-known class of versatile biscationic amphiphiles, owing to their low cost and ease of preparation. Asymmetric TMEDA derivatives, however, have been studied significantly less, particularly in regards to their antimicrobial properties. We have thus prepared a series of 36 mono-and bis-alkylated TMEDA derivatives to evaluate their inhibition of bacterial growth. This series of compounds showed low micromolar activity against a panel of four bacteria. Optimal inhibition was observed when the biscationic amphiphiles possessed modest asymmetry and were composed of between 20 and 24 total carbon atoms in the side chains. These amphiphiles were prepared in a simple two-step procedure, utilizing inexpensive materials and atom-economical reactions, making them practical for further development.
- Black, Jacob W.,Jennings, Megan C.,Azarewicz, Julianne,Paniak, Thomas J.,Grenier, Melissa C.,Wuest, William M.,Minbiole, Kevin P.C.
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- Synthesis and Physicochemical Properties of Double-Chain Cationic Surfactants
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In this study two types cationic surfactants were synthesized, purified, and characterized in our laboratory. One them is a series of cationic surfactants, a two tail-one head surfactant, N,N-dialkyl-N,N-diethylammonium bromide, abbreviated as "m-0-m" (m = 10, 12, and 16). The other type is N,N′-dialkyl-N,N,N′,N′-tetramethyl-N,N′-ethanediyl-diammonium dibromide, two tail-two head surfactants, abbreviated as "m-2-m" (m = 12 and 16). Once NMR spectra (1H NMR, 13C NMR) for all the gemini surfactants that were synthesized were taken, then the melting temperatures (TM) were measured. These surfactants have very high surface activity. The main goal of our study was to examine some properties of these two tail cationic surfactants by manipulating their dimeric structure. The effects of alkyl chain length and headgroup on surfactant self-assembly in solution were investigated. Critical micelle concentrations (CMC), degree of micelle ionization (α), and Krafft temperatures (TK) of 1 wt % aqueous solutions of these surfactants were determined by conductance measurements. Krafft points were found to be dependent on the number of carbon atoms in the alkyl chain and decreased by the addition of the electrolytes. The absence of the spacer group, peculiar to these twin tail cationic surfactants, may confer relatively low flexibility to the molecules, with potential implications on the interfacial properties, namely, on micellization.
- Engin ?zdil, Sinem,Akba?, Halide,Boz, Mesut
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- Gemini surfactants foam formation ability and foam stability depends on spacer length
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A series of cationic gemini surfactants containing different spacer length were synthesized and analyzed structurally. It was shown that the surface tension (σ) and critical micelle concentration (CMC), which had a maximum for the n-C4H8 spacer depended on the spacer length. The foaming ability and foam stability are high for the gemini surfactants with short spacers (C2H4 to n-C4H8), while longer spacers lead to a distinct decrease of these foam parameters. Foaming properties are discussed in terms of configuration and conformation of a surfactant molecule and in relation to micellization state kinetic.
- Kuliszewska, Edyta,Brecker, Lothar
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- Effects of structure dissymmetry on aggregation behaviors of quaternary ammonium gemini surfactants in a protic ionic liquid EAN
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The aggregation behaviors of a series of dissymmetric cationic Gemini surfactants, [CmH2m+1(CH3)2N(CH 2)2N(CH3)2CnH 2n+1]Br2, designated as m-2-n (with a fixed m + n = 24, m = 16, 14, 12) have been investigated in a protic ionic liquid, ethylammonium nitrate (EAN). Surface tension, polarized optical microscopy (POM), small-angle X-ray scattering (SAXS), and rheological measurements are adopted to investigate the micellization and lyotropic liquid crystal (LLC) formation. The obtained results indicate that the structure dissymmetry plays an important role in aggregation process of m-2-n. With increasing degree of dissymmetry, the critical micellization concentration, the maximum reduction of solvent surface tension, and the minimum area occupied per surfactant molecule at the air/EAN interface all become smaller. The thermostability of formed LLCs is therefore improved because of the more compact molecules. These characteristics can be explained by the enhancement of solvophobic effect due to the increased structure dissymmetry of Gemini surfactants.
- Wang, Xudong,Li, Qintang,Chen, Xiao,Li, Zhihong
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- BISCATIONIC AND TRISCATIONIC AMPHILES AS ANTIMICROBIAL AGENTS
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The present disclosure provides an antimicrobial composition including a compound which is a biscationic or triscationic amphiphile, and the method of making such an antimicrobial composition, and the method of using such a compound or composition for antimicrobial use. The antimicrobial composition can include a compound having the formula (I) wherein R is a methylene group unsubstituted or optionally substituted, s is an integer in the range from 1 to 6, R1, R2, R3 or R4 is H or a C 1-4 alkyl unsubstituted or optionally substituted, X is a halogen, m and n are integers in the range from 5 to 25, and m is not equal to n. Alternatively, the antimicrobial composition can comprise a compound having the formula (III) or (IV) wherein R1, R2, R3, R4 R5, or R6 is H or a C1-4 alkyl unsubstituted or optionally substituted, X or Y is a halogen, and m and n are integers in the range from 5 to 25.
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Paragraph 0098; 0099
(2015/05/26)
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- Metal complexes catalyzed oxidative coupling of 2,6-dimethylphenol in micellar media
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The oxidative coupling reaction of 2,6-dimethylphenol (DMP) with H 2O2 catalyzed by two copper(II) complexes (2,2′-dipyridylamine copper(II), L1Cu and N,N′-bis (2-pyridinecarbonyl) ethylenediamine copper(II), L2Cu) in cationic surfactant cetyl trimethylammonium bromide (CTAB), gemini surfactants ethanediyl-1,2-bis(dodecyldimethylammonium bromide) (12-2-12), dimethylene-1,2-bis(cetyltrimethylammonium bromide) (16-2-16), anionic surfactant sodium dodecyl benzene sulfornate (SDBS) and nonionic surfactant Triton X-100 (TX-100) micellar media were comparatively investigated at 25 °C. The kinetics of formation of 3,3′,5,5′-tetramethyl-4, 4′-diphenoquinone (DPQ) was studied. The kinetic parameters k2 and Km were obtained at pH 7.01. L1Cu displayed better catalytic activity than L2Cu in mentioned above systems. For L 1Cu catalyzed systems, the cationic surfactant CTAB, 12-2-12 and 16-2-16 micellar media accelerated the oxidation of DMP. And the TX-100 and SDBS micelles showed little effect on reaction rate compared with the buffer solution. For the L2Cu catalyzed systems, these surfactants all inhibited the oxidation of DMP, and especially, the oxidation of DMP was not found in SDBS micellar solution in the catalyzed system at pH 7.01 and 25 °C. Micelles showed great influence on the yield of product and the selectivity of PPO. Under this work's conditions, DPQ was easily generated in aqueous solution, while PPO was remarkably promoted in micellar media, especially in SDBS micellar solution. As a green technology process, one outstanding advantage of this catalyzed system was that the products of polymer can be easily separated from the solution and the catalysts still remain in the micellar solution.
- Li, Xiao-Hong,Meng, Xiang-Guang,Pang, Qin-Hui,Liu, Shan-Dong,Li, Jian-Mei,Du, Juan,Hu, Chang-Wei
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experimental part
p. 88 - 92
(2010/12/18)
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- Specific ion pairing and interfacial hydration as controlling factors in gemini micelle morphology. Chemical trapping studies
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Results from chemical trapping experiments in micellar solutions containing 1.5-5 mM aqueous solutions of three didodecyl dicationic dibromide gemini surfactants with different methylene spacer lengths (12-n-12 2Br where n = 2-4 CH2 groups) gav
- Geng, Yan,Romsted, Laurence S.,Menger, Fred
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p. 492 - 501
(2007/10/03)
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- Quaternary ammonium compounds
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Quaternary ammonium compounds have the formula R1 R2 R3 N+ (CH2)m Y X- wherein R1 is an alkyl containing 8-20 carbon atoms, R2 is an alkyl containing 8-20 carbon atoms or methyl or ethyl, R3 is methyl or ethyl, m is an integer from 1-6, X is an anion and Y is a group having the structure --Z, --OH, --OR4, --OC(O)R5, --CN, --O--S(O) (O)--OQ, --C(O)OR6, --C=CH, --SR7, --S(O)(O)R8, --S(O)R9, --NR10 R11 and --CH=CH2 wherein R4, R5, R6, R7, R8, R9, R10, R11 are alkyls containing 1-12 carbon atoms or are phenyl and Z is halogen and Q is hydrogen or a cation having been found to be very effective bactericides.
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