- Cleft Formation upon Polymerization of Surfactant Vesicles
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Morphological consequences of the photopolymerization of vesicles prepared from (C18H37)2N+(CH3)CH2C6H4-p-CH-=CH2*Cl-, 1, have been investigated by using 8-hydroxy-1,3,6-pyrenetrisulfonate (POH) as a reporter group.Static and dynamic laser light scattering established the hydrodynamic radius and the molecular weight of 1 vesicles to be 425 +/-25 Angstroem and 2.3E7.Neither of these values changed upon polymerization.POH was shown to bind appreciably to 1 vesicles.Excitation of POH, following immediately its addition to nonpolymerized 1 vesicles, resulted in fluorescence emission with maxima at 440 and 520 nm.Incubation led to time-dependent changes of this spectra.Increasing incubation time of POH containing nonpolymerized 1 vesicles resulted in the gradual disappearance of the emission band at 520 nm and in the concomitant increase of the emission band at 440 nm.Fluorescence spectra of POH did not show any time-dependent changes following its addition to polymeryzed 1 vesicles.These results were interpreted in terms of the gradual penetration of POH into nonpolymerized 1 vesicles and in terms of long-term stabilization of POH in the clefts formed on the vesicle surface upon pulling the surfactant head groups together by photopolymerization.Differences between nonpolymerized and polymerized vesicles also manifested in the excited state protonation equilibria (POH)* (PO-)* + H+.A koff8 value of 4.3E9 s-1 was obtained in nonpolymerized vesicles immediately after the POH injection.Following a day of incubation no excited-state proton ejection could be observed in nonpolymerized 1 vesicles.Consequently, a koff* value of 6.1E9 s-1 was observed in nonpolymerized vesicles both immediately and 1 day subsequent to the addition of POH to polymerized 1 vesicles.Similar behavior has been observed for the steady-state (P) and nanosecond time-resolved polarizations, τR values, of POH, as well as that for the ground state PO- reprotonation (governed by Kon) in nonpolymerized and polymerized 1 vesicles.In nonpolymerized 1 vesicles, P values increased (from 0.12 to 0.19), τr was determined to be >/= 50 ns, and kon values (4E8 M-1 s-1) became unobservable after a day of incubation.In polymerized 1 vesicles, P values of 0.08, values τR of 4 ns, and kon values 8E8 M-1 s-1 remained unaffected by incubation.
- Nome, Faruk,Reed, Wayne,Politi, Mario,Tundo, Pietro,Fendler, Janos H.
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- PROCESS FOR PRODUCING NITROGEN-CONTAINING COMPOUNDS
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The present invention relates to a process for producing a tertiary amine in the presence of a catalyst containing copper and at least one element selected from the group consisting of elements belonging to Groups 2, 3, 7 and 12 of the Periodic Table (long form of the periodic table), said process including the steps of (a) reducing an amide compound in a hydrogen atmosphere; and (b) introducing a dialkyl amine containing a linear or branched alkyl group having 1 to 6 carbon atoms into a reaction product obtained in the step (a), and treating the reaction product with the dialkyl amine. The present invention provides a process for producing high-purity aliphatic tertiary amines containing a less amount of by-products by reducing aliphatic acid amides under moderate conditions using a chromium-free catalyst, as well as a process for producing amine derivatives such as amine oxide by using the aliphatic tertiary amines, with a good productivity in an economical manner.
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Page/Page column 23-24
(2009/04/25)
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- METHOD FOR PRODUCING NITROGEN-CONTAINING COMPOUND
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The present invention provides a process for producing high-purity aliphatic tertiary amines containing a less amount of by-products by subjecting aliphatic acid amides to hydrogenation reduction under moderate conditions, as well as a process for producing amine derivatives from the aliphatic tertiary amines, with a good productivity in an economically advantageous manner. The present invention relates to a process for producing an aliphatic tertiary amine by subjecting a specific aliphatic amide to hydrogenation reduction in the presence of a catalyst containing copper and at least one element selected from the group consisting of elements belonging to Groups 2, 3 and 7 of the Periodic Table; the catalyst; and a process for producing amine oxide by reacting the tertiary amide obtained by the above production process with hydrogen peroxide.
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Page/Page column 10
(2008/12/09)
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- A Hydrolytic Reporter of Cu(II) Availability in Artificial Liposomes
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The dioctadecyl ammonium surfactant 1, functionalized with a p-nitrophenyl ester of picolinic acid has been synthesized and its hydrolysis in covesicular blends of nonfunctional surfactants dihexadecyldimethylammonium bromide, 3, dioctadecyldimethylammonium bromide, 4, and racemic 1,2-bis(palmitoyloxy)-3-(trimethylammonium)propyl bromide, 5, studied after addition of Cu(II) ions pH=5.0 and different temperatures.The cleavage of 1 gives the p-nitrophenoxide surfactant 2, which shows a strong absorption band at 400 nm.Clear biphasic kinetics were observed for all vesicular systems at a temperature below the gel-liquid crystal phase transition temperature (Tc) of the membrane; the first, faster process (ca. 60percent ester cleaved) was associated with the Cu(II)-catalyzed hydrolysis of the exovesicular ester; the slower one (the remaining ca. 40percent of the ester cleaved) was associated with the uncatalyzed hydrolysis of the endovesicular ester.Above Tc only a monoexponential process was observed.Variable temperature experiments allowed one to conclude that the cationic vesicles studied are totally impermeable to Cu(II) ions either below or above their Tc which controls the rate of the transbilayer movements of the lipids.
- Ghirlanda, Giovanna,Scrimin, Paolo,Tecilla, Paolo,Tonellato, Umberto
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p. 3025 - 3029
(2007/10/02)
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- Chemical Differentiation of Bilayer Surfaces in Functional Dialkylammonium Ion Vesicles: Observation of Surfactant Flip-Flop
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Cationic p-nitrophenyl carbonate and p-nitrophenyl benzoate functionalized di-n-octadecylmethylammonium ion surfactants 6 and 7 were synthesized.Vesicles of 6 or covesicles of (1:9) 7 and 5, created at pH 3.9, gave rapid, partial p-nitrophenylate cleavage at pH 7.9-8.0 (from 6) or rapid, partial benzoate cleavage by external thiolate ions at pH 7.9-8.0 (from 7), attributed to surface-specific exovesicular reactions of 6 or 7/5.These exovesicular cleavages at pH 8 and 25 deg C are apparently faster than reagent permeation across the bilayers to the endovesicularfunctional groups at pH 3.9.The dioctadecylammonium ion vesicles, in contradistinction to their dihexadecyl analogues, are able to maintain the indicated pH gradient long enough at 25 deg C to permit the surface-specific esterolyses.Relaxation of the pH gradient and endovesicular cleavages follow upon enhancement of the fluidity of the vesicle bilayers either with the application of heat or with additives such as 1-hexanol or dioctyldimethylammonium chloride.In the surface-differentiated 7/5 covesicles, "flip-flop" of intact 7 from endovesicular to exovesicular sites can be promoted and visualized by experiments that involve incubation of the vesicles at 38-40 deg C, pH 3.9, for 1-12 min.
- Moss, Robert A.,Bhattacharya, Santanu,Chatterjee, Swati
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p. 3680 - 3687
(2007/10/02)
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- Non-hygroscopic trialkylamine oxides
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A solid non-hygroscopic flakeable di-C14-30 alkyl C1-2 alkylamine oxide is made by reacting di-C14-30 alkyl C1-2 alkylamine with aqueous hydrogen peroxide containing at least 40 weight percent H2 O2 in the absence of a solvent.
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- Process for the preparation of tertiary aliphatic amines
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A process for the preparation of tertiary aliphatic amines containing an alkyl or alkenyl radical having 8 to 24 carbon atoms and at least one methyl group by reacting a liquid alcohol or aldehyde having 8 to 24 carbon atoms in the presence of a copper-chromium oxide catalyst with a gaseous mixture containing hydrogen and a lower primary or secondary alkyl amine having at least one methyl group, the amine proportion of the gas mixture being in the range of from 1 to 20% by volume, eliminating the water having been formed in the reaction from the gaseous mixture, and recirculating the gaseous mixture continuously back into the liquid alcohol or aldehyde.
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