- Preparation and Characterization of Glycerol-Based Cleavable Surfactantsand Derived Vesicles
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Four cleavable double-chain surfactants were synthesized: trimethylammonium methanesulfonate 1a, the analogous bromide 1b, dimethyl(3-sulfopropyl)ammonium hydroxide inner salt 1c, and sodium 3--1-propanesulfonate 1d.Vesicles of 1a, 1b, and 1d prepared by sonication were characterized by 1H NMR line width narrowing, dynamic laser light scattering, differential scanning calorimetry, and dye entrapment and leakage studies.In vesicular form, the hydrolytic lability of 1d was greater than that of 1a/1b, due to a combination of electrostatic effects resulting from the different subtituents on the dioxolane ring.Neutral organic compounds can be readily isolated from vesicular solutions of 1d after its hydrolysis.Thus 1d is appropriate for the applicaton of vesicular media to preparative chemistry.
- Jaeger, David A.,Jamrozik, Janusz,Golich, Timothy G.,Clennan, Malgorzata Wegrzyn,Mohebalian, Jamshid
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- Effective deoxygenation of fatty acids over Ni(OAc)2 in the absence of H2 and solvent
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Different metal acetate salts were systematically examined for the catalytic deoxygenation of stearic acid in the absence of H2 and solvent for the first time. Ni(OAc)2 exhibited the highest activity with 62% yield achieved at 350°C for 4.5 h with only 1 mol% (0.2 wt%) of the catalyst. Even with 0.25 mol% (0.05 wt%) catalyst, around 28% yield was achieved within 2 h at 350°C with 89% selectivity to C17 hydrocarbons. The activity based on C17 yields per Ni was 14.5 mol mol-1 h-1, considerably higher than that in previous reports. The catalytically active species were identified to be in situ generated Ni nanoparticles (8-10 nm) formed from the decomposition of the metal precursor with stearic acid as a stabilizer. A new reaction pathway of alkane formation from stearic acid via anhydride intermediate decarbonylation under an inert gas atmosphere was proposed. The excellent stability of the catalyst was demonstrated by re-adding a substrate to the system, during which the activity remained constant through four consecutive runs. The novel catalytic system was found to be applicable to a range of fatty acids and triglycerides with varying activities.
- Li, Wenjing,Gao, Yongjun,Yao, Siyu,Ma, Ding,Yan, Ning
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p. 4198 - 4205
(2015/08/11)
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- Impact of the oxygen defects and the hydrogen concentration on the surface of tetragonal and monoclinic ZrO2 on the reduction rates of stearic acid on Ni/ZrO2
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The role of the specific physicochemical properties of ZrO2 phases on Ni/ZrO2 has been explored with respect to the reduction of stearic acid. Conversion on pure m-ZrO2 is 1.3 times more active than on t-ZrO2, whereas Ni/m-ZrO2 is three times more active than Ni/t-ZrO2. Although the hydrodeoxygenation of stearic acid can be catalyzed solely by Ni, the synergistic interaction between Ni and the ZrO2 support causes the variations in the reaction rates. Adsorption of the carboxylic acid group on an oxygen vacancy of ZrO2 and the abstraction of the a-hydrogen atom with the elimination of the oxygen atom to produce a ketene is the key to enhance the overall rate. The hydrogenated intermediate 1-octadecanol is in turn decarbonylated to heptadecane with identical rates on all catalysts. Decarbonylation of 1-octadecanol is concluded to be limited by the competitive adsorption of reactants and intermediate. The substantially higher adsorption of propionic acid demonstrated by IR spectroscopy and the higher reactivity to O2 exchange reactions with the more active catalyst indicate that the higher concentration of active oxygen defects on m-ZrO2 compared to t-ZrO2 causes the higher activity of Ni/m-ZrO2.
- Foraita, Sebastian,Fulton, John L.,Chase, Zizwe A.,Vjunov, Aleksei,Xu, Pinghong,Barth, Eszter,Camaioni, Donald M.,Zhao, Chen,Lercher, Johannes A.
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p. 2423 - 2434
(2015/02/05)
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- A PROCESS FOR THE DECARBOXYLATION OF FATTY ACIDS
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A process for the production of a ketone having a carbon number between about 20 and about 40 comprising contacting fatty acids containing from about 10 to about 21 carbons atoms with a hydrotalcite catalyst under conditions effective to decarboxylate said acids. More particularly said decarboxylation conditions comprise: a temperature in the range between about 300°C and about 400°C; a pressure in the range between about 0.01 and about 5 bar; and a weight hourly space velocity (WHSV) of from about 0.1 to about 10 hr-1.
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Page/Page column 12
(2008/06/13)
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- Super water-repellent surfaces resulting from fractal structure
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Super water-repellent surfaces showing a contact angle of 174° for water droplets have been made of alkylketene dimer (AKD). Water droplets roll around without attachment on the super water-repellent surfaces when tilted slightly. The AKD is a kind of wax and forms spontaneously a fractal structure in its surfaces by solidification from the melt. The fractal surfaces of AKD repel a water droplet completely and show a contact angle larger than 170° without any fluorination treatments. Theoretical prediction of the wettability of the fractal surfaces has been given in the previous paper.3 The relationship between the contact angle of the flat surface θ and that of the fractal surface θf is expressed by the equation cos θf = (L/l)D-2 cos θ where (L/l)D-2 is the surface area magnification factor. The fractal dimension of the solid AKD surface was determined to be D ≈ 2.3 applying the box-counting method to the SEM images of the AKD cross section. L and l, which are the largest and the smallest size limits of the fractal behavior of the surface, are also estimated from the box-counting method. The contact angles of some water/1,4-dioxane mixtures on the fractal and the flat AKD surfaces were determined, and the values of cos θf were plotted against cos θ. The plot of cos θf against cos θ agrees well with the theoretical prediction. It has been demonstrated by this work that the fractal concept is a powerful tool to develop some novel functional materials.
- Shibuichi, Satoshi,Onda, Tomohiro,Satoh, Naoki,Tsujii, Kaoru
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p. 19512 - 19517
(2007/10/03)
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- Formation of long-chain ketones in ancient pottery vessels by pyrolysis of acyl lipids
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Structural and isotopic (δ13C) evidence indicates the formation of series of long-chain ketones in archaeological pottery can occur by condensation of long-chain carboxylic acids. The formation of the ketones is confirmed by pyrolysis of free fatty acids or triacylglycerols in the presence of fired clay matrix.
- Evershed, Richard P.,Stott, Andrew W.,Raven, Anthony,Dudd, Stephanie N.,Charters, Stephanie,Leyden, Ann
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p. 8875 - 8878
(2007/10/02)
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- Glycerin derivatives and process for producing the same
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Glycerine derivatives represented by formula (1A), (2A) and (3A): wherein R1a, R2a, R1b, R2b, R1c, and R2care as defined in the disclosure, and process for producing glycerin derivatives, including the glycerin derivatives (1A), (2A) and (3A), are disclosed. The glycerin derivatives have satisfactory physical properties and are applicable as lubricants or polar oils and also have mutual effects with water and are applicable as emulsifying agents or moisture retaining agents. The process makes it possible to synthesize glycerin derivatives from easily and economically available aldehydes or ketones in high yields.
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- PREPARATION OF KETONES BY A NOVEL DECARBALKOXYLATION OF β-KETO ESTERS: STEREOELECTRONIC ASSISTANCE TO C-C BOND FISSION
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Reaction of β-keto esters with the sodium derivative of propane-1,2-diol in an excess of anhydrous propane-1,2-diol causes facile decarboxylation to ketones in excellent yields.
- Aneja, R.,Hollis, W. M.,Davies A. P.,Eaton, G.
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p. 4641 - 4644
(2007/10/02)
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