- Structural Studies of Donor-Free and Donor-Solvated Sodium Carboxylates
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Focusing mainly on sodium 2-ethylhexanoate, this study reveals that the carboxylate exists as a dimer in MeOD solution as evidenced by Diffusion Ordered NMR SpectroscopY (DOSY). Two crystalline varieties with distinct polymeric structures have been synthesised and crystallographically characterised. A mixed 1,10-phenanthroline–water solvate [{(C5H10)(C2H5)COONa.(H2O)[1,10-phen]}2]∞ contains dimeric [Na(OH2)]2 subunits, which propagate through hydrogen bonds between O atoms of the carboxylate and OH water bonds. Adjacent polymeric chains interdigitate with each other through π?π interactions between 1,10-phen rings. Solvent-free sodium 2-ethylhexanoate has five-coordinate cations comprising one bidentate chelating and three monodentate carboxylate oxygen atoms. Here, the packing arrangement is different with the central hydrophilic (NaO2)∞ core surrounded by a wrapping of disordered alkyl groups. A similar polymeric structure is observed for the crystalline DMSO-solvated sodium valproate [{(C3H7)(C4H8)COONa.(DMSO)}]∞. This adopts a layered arrangement comprising alternating sodium carboxylate hydrophilic layers and hydrophobic organic bilayers.
- Gauld, Richard M.,McLellan, Ross,Kennedy, Alan R.,Carson, Freya J.,Barker, Jim,Reid, Jacqueline,O'Hara, Charles T.,Mulvey, Robert E.
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- Self-Replicating Micelles: Aqueous Micelles and Enzymatically Driven Reactions in Reverse Micelles
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In this paper we present a further development of the self-replication system that was originally described for reverse micelles (Bachmann, P. A.; Walde, P.; Luisi, P. L.; Lang, J. J. Am. Chem. Soc. 1990, 112, 8200-8201). The definition of the term "self-replication" requires that the population growth of the structure is due to a reaction which takes place within the geometrical boundary of the structure itself. Here it is shown that it is possible to design both reverse and aqueous micelles that are able to self-replicate due to a reaction occurring within the micelle structure. The surfactant used was sodium octanoate, which forms micelles in water in the presence of 1-octanol as cosurfactant. Oxidation of the cosurfactant by permanganate ion converts it to molecules of the corresponding salt, which spontaneously assemble into new micelles. The reaction goes to completion, producing a 43% increase in the micelle concentration, as judged by time-resolved fluorescence quenching. Octanoate in the presence of octanol also forms reverse micelles in 85:15 (v/v) isooctane/1-octanol, and the same oxidation reaction brings about an increase in the micelle concentration by a factor of 9. The reverse micellar system sodium octanoate/octylamine is capable of hosting lipases, which are restricted to the water pool. The hydrolysis of trioctanoyl glycerol, a substrate for these enzymes, which is only soluble in the organic phase, takes place at the micellar interface and increases the micelle concentration by a factor of 4. The implication of these data for chemical autopoiesis (a theory that attempts to define the living in terms of chemical self-organization and self-production) is discussed.
- Bachmann, Pascale Angelica,Walde, Peter,Luisi, Pier Luigi,Lang, Jacques
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- TARGETED NANOPARTICLES OF WELL-DEFINED AND REPRODUCIBLE SIZES
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The invention relates to a nanoparticle preparation comprising nanoparticles of well-defined and reproducible sizes, that are substantially free of aggregate formation.
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Page/Page column 51
(2021/02/12)
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- Fatty acid ionic liquids as environmentally friendly lubricants for low friction and wear
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Vegetable oils are environmentally-friendly, sustainable and rich source of fatty acids, and have been used as lubricants since ancient times. The carboxylic group of fatty acids interacts with metal surface and forms the tribo-chemical thin film of low shear strength under the boundary lubrication, which reduces the friction and the wear. Herein, four fatty acids having variable chain length and unsaturated sites are selected as anionic precursors to prepare the tetrabutylammonium-fatty acid ionic liquids. The preparation of these ionic liquids is confirmed by FTIR and NMR (1H and 13C) analyses. The chain length and degree of unsaturation in the fatty acid anions control the viscosity, melting temperature, crystallization temperature and latent heat of fatty acid ionic liquids. These ionic liquids as lubricants exhibited significantly lower friction (18-50%) compared to polyol ester lube base oil. Further, the degree of friction reduction is largely influenced by the structure of the constituent fatty acid anion. The oleate anion showed the best tribo-performance among all fatty acid ionic liquids being studied. The elemental mapping of worn surfaces revealed the formation of fatty acid ionic liquids constituted a tribo-chemical thin film. Being halogen-free and abundantly available sources of fatty acid precursors, these ionic liquids promise immense potential for tribological applications, where the friction and environment are of prime importance.
- Gusain, Rashi,Khatri, Om P.
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p. 3462 - 3469
(2016/01/20)
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- A green resolution-separation process for aliphatic secondary alcohols
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In order to obtain both enantiomers of aliphatic secondary alcohols via a greener method, the four-step resolution-separation process involving lipase-catalyzed enantioselective esterification and hydrolysis as well as two separation procedures both via heterogeneous azeotropic distillation was developed. (S)-2-Pentanol (ee = 98.6%), (R)-2-pentanol (ee >99%), (S)-2-octanol (ee = 98.2%), and (R)-2-octanol (ee = 98.5%) were all produced in high purity (>98%) and high yield (>90%). In addition to the two model substrates, this method could also be applied to the resolution of other aliphatic secondary alcohols.
- Ren, Liwei,Xu, Tian,He, Ruoping,Jiang, Zhenhua,Zhou, Hua,Wei, Ping
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p. 249 - 253
(2013/05/09)
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- Solubilization and catalytic behavior of micellar system based on gemini surfactant with hydroxyalkylated head group
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The correlation between aggregation, solubilization and catalytic properties has been found for series of cationic surfactants with hexadecyl radical of both monomeric and dimeric structures. The highest catalytic effect in the series, reaching three orde
- Mirgorodskaya, Alla B.,Yackevich, Ekaterina I.,Lukashenko, Svetlana S.,Zakharova, Lucia Ya.,Konovalov, Alexander I.
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scheme or table
p. 106 - 109
(2012/07/27)
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- A simple and efficient large-scale synthesis of metal salts of medium-chain fatty acids
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A simple, inexpensive, one-step general procedure was developed for the preparation of medium-chain fatty acid (MCFA) metal salts. This approach offers the advantage of a practical route and is superior to literature methods. Also, it overcomes many of the limitations previously reported for the preparation of fatty acid salts. The potential utility of this method is illustrated by the production of pilot-scale quantities of high-purity (>99.9%) sodium decanoate.
- Zacharie, Boulos,Ezzitouni, Abdallah,Duceppe, Jean-Simon,Penney, Christopher
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experimental part
p. 581 - 583
(2010/04/22)
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- PREPARATION OF METAL SALTS OF MEDIUM-CHAIN FATTY ACIDS
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A process for the preparation of metal salts of a medium-chain length monocarboxylic fatty acid comprises reacting the precursor free fatty acid, dissolved in a suitable solvent, with the appropriate metal salt. The process uses a relatively high concentration of free fatty acid as a soluble reactant and produces metal fatty acid salts at high purity and high yield at a reasonable cost.
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Page/Page column 5 - 6
(2008/06/13)
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- Photolysis of phenacyl esters in a two-phase system
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Phenacyl esters are useful photoremovable protecting groups for carboxylic acids in organic synthesis and biochemistry. In this work, simple one-pot arrangements of the phenacyl and 2,5-dimethylphenacyl ester photolysis are proposed. The reactions were performed in both the benzene/water two-phase system and in water. Cetyltrimethylammonium bromide was found to increase substantially the efficiency of the deprotection as well as the purity of the products by lowering the interfacial tension between the phases. Utilizing water as a medium significantly reduced the necessity to use environmentally malign organic solvents. The overall yields varied from 72 to 98% depending on the reaction conditions.
- Ruzicka, Radovan,Zabadal, Miroslav,Klan, Petr
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p. 2581 - 2590
(2007/10/03)
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- Ion-exchange equilibrium in synthesis of acids on KU-2(H) cation exchanger and of salts on KB-4P-2 cation exchanger
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Advisability of ion-exchange synthesis of acids on strongly acidic KU-2 cation exchanger and of salts on weakly acidic KB-4P-2 cation exchanger is studied.
- Saidakhmedov,Arslanov,Vulikh
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p. 211 - 215
(2007/10/03)
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- Capryloyloxyalkyl acrylates, polymers and copolymers thereof and their preparation
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This invention relates to capryloyloxyalkyl acrylates of the general formula, CH2=CH-CO-O-R-O-CO-(CH2)6-CH3,wherein R is an alkylene group of 2 to 6 carbon atoms, and their polymers and copolymers containing structure units of the general formula where R are identical or different alkylene groups as defined above, and the polymer contains either 100 % of the capryloyloxyalkyl acrylate structure units or additional vinyl monomer and particularly vinyl chloride structure units in the main chain or side chains. The invention also pertains to methods for the preparation of capryloyloxyalkyl acrylates corresponding intermediates and to methods for producing the polymers and copolymers containing capryloyloxyalkyl acrylate structure units either by polymerization or copolymerization of capryloyloxyalkyl acrylates with the respective vinyl comonom ers or by polymerization of the vinyl comonomers, particularly vinyl chloride, in the presence of a poly(capryloyloxyalkyl acrylate). The invention is particularly applicable to the production of new types of plasticized PVC where migration and extraction of the plasticizing component is excluded.
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- Einfluss verschiedener Vorbehandlungen auf die Strukturbildung und thermischen Umwandlungserscheinungen ausgewaehlter Natrium-Seifen
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Das thermische Phasenverhalten und die strukturellen Abwandlungen ausgewaehlter Na-Seifen (Na-Kaprylat, Na-Palmitat und Na-Stearat) wurden mit den Methoden der Differential-Scanning-Kalorimetrie, Roentgen- und Elektronenbeugung untersucht.Der Einfluss verschiedener Vorbehandlungen auf die Struktur und thermischen Umwandlungserscheinungen stand im Mittelpunkt des Interesses.Folgende Ergebnisse sind hervorzuheben: 1.Verschiedene Vorbehandlungen (Probenpraeparationen) beeinflussen die Restwassermengen in den Na-Seifen.Zur Herstellung wasserfreier Produkte muss fest gebundenes Wasser (ca. 1/2 mol) unter drastischen Bedingungen entfernt werden. 2.Die Umwandlungstemperaturen und -enthalpien unterschiedlicher Formen obiger Na-Seifen werden angegeben und mit dem Wassergehalt in Beziehung gesetzt. 3.Mit Ausnahme des Kristalls laesst sich der feste Zustand verschieden vorbehandelter Seifen strukturell nicht einheitlich deuten.Die Grenzen bekannter Modellvorstellungen werden diskutiert. 4.Der Kristallzustand laesst sich nur durch Loesungsmittelkristallisation erreichen.Im Kristall sind die Molekuele (NaC18) in einem Gitter der Abmessungen a=9,19 Angstroem und b=8,05 Angstroem gepackt.Die trikline Subzelle TII als Anordnung der aliphatischen Ketten wurde durch Elektronenbeugung an Mikroeinkristallen gesichert.Als Ueberstrukturelemente koennen duenne lamellare Fasern angenommen werden.Eine periodische Anordnung derartiger Fasern ist nachgewiesen worden. 5.Aus den Roentgenbeugungsaufnahmen folgt, dass das Aufschmelzen der Ketten fuer das NaC8, NaC16 und NaC18 einheitlich bei etwa 118 deg C satttfindet und mit einer thermischen Kontraktion und einem Wechsel in der Ueberstruktur verbunden ist.Das Roentgenbeugungsverhalten beim Aufheizen verschiedener Zustaende der Seifen ist jeweils unterschiedlich und konnte nicht in allen Faellen strukturell gedeutet werden.Die Hochtemperaturphasen liessen sich nur beim wasserfreien NaC18 mit dem Modell zentrierter Baenderstrukturen in Uebereinstimmung bringen.
- Foerster, G.,Brezesinski, G.,Gerlach, E.,Maedicke, A.,Doerfler, H.-D.
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p. 1009 - 1031
(2007/10/02)
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