- Synthesis, characterization, and electrochemical behavior of a cobalt(II) salen-like complex
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A new tetradentate cobalt(II)-Schiff base complex has been synthesized via the reaction of the ligand 2,2′-((1E,1′E)-(ethane-1,2-diylbis(azanylylidene))bis(ethan-1-yl-1-ylidene))bis(4-((methyl(phenyl)amino)methyl)phenol) with a stoichiometric amount of cobalt(II) acetate tetrahydrate in absolute ethanol. This cobalt(II) complex has been characterized with the aid of several spectroscopic techniques (FT-IR, UV-Vis, and mass spectrometry) as well as by thermal (TGA and DTA) and elemental analysis. Cyclic voltammetry has been employed to examine the redox behavior of the cobalt(II) complex in dimethylformamide (DMF) containing 0.10 M tetra-n-butylammonium tetrafluoroborate (TBABF4). In addition, the electrogenerated cobalt(I) form of the complex has been (a) employed as a catalyst for the reduction of 1-iododecane and (b) compared with the behavior of cobalt(I) salen. Finally, the cobalt(II) complex has been subjected to anodic electropolymerization onto the surface of a glassy carbon electrode in DMF containing 0.10 M tetra-n-butylammonium perchlorate (TBAP).
- Ourari, Ali,Messali, Salima,Bouzerafa, Brahim,Ouennoughi, Yasmina,Aggoun, Djouhra,Mubarak, Mohammad S.,Strawsine, Lauren M.,Peters, Dennis G.
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Read Online
- Polymer-bound Alkali Metal Aromatic Radical Anions
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Polystyrene-bound anthracene has been prepared and found to react with sodium-naphthalene to give a polymeric radical anion whose chemistry is analogous to that of soluble alkali metal aromatic radical anions.
- Bergbreiter, David E.,Killough, James M.
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Read Online
- Iron-catalysed sp3-sp3 cross-coupling reactions of unactivated alkyl halides with alkyl grignard reagents
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Iron-catalysed sp3-sp3 Kumada coupling with primary and secondary alkyl halides (RX) and alkyl Grignard reagents has been achieved in low to good yields depending on the nature of the R group.
- Dongol, Krishna G.,Koh, Huishi,Sau, Manisankar,Chai, Christina L.L.
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Read Online
- Cobalt-Catalyzed Csp3?Csp3Homocoupling
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An efficient and easy method for Csp3?Csp3homocoupling was developed using cobalt bromide as catalyst. A series of functionalized alkyl bromides and alkyl chlorides were coupled in high yields under mild conditions. This reaction seems to involve a radical intermediate. (Figure presented.).
- Cai, Yingxiao,Qian, Xin,Gosmini, Corinne
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supporting information
p. 2427 - 2430
(2016/08/16)
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- Selective Catalytic Hydrogenolysis of Carbon-Carbon σ Bonds in Primary Aliphatic Alcohols over Supported Metals
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The selective scission of chemical bonds is always of great significance in organic chemistry. The cleavage of strong carbon-carbon σ bonds in the unstrained systems remains challenging. Here, we report the selective hydrogenolysis of carbon-carbon σ bonds in primary aliphatic alcohols catalyzed by supported metals under relatively mild conditions. In the case of 1-hexadecanol hydrogenolysis over Ru/TiO2 as a model reaction system, the selective scission of carbon-carbon bonds over carbon-oxygen bonds is observed, resulting in n-pentadecane as the dominant product with a small quantity of n-hexadecane. Theoretical calculations reveal that the 1-hexadecanol hydrogenolysis on flat Ru (0001) undergoes two parallel pathways: i.e. carbon-carbon bond scission to produce n-pentadecane and carbon-oxygen bond scission to produce n-hexadecane. The removal of adsorbed CO on a flat Ru (0001) surface is a crucial step for the 1-hexadecanol hydrogenolysis. It contributes to the largest energy barrier in n-pentadecane production and also retards the rate for n-hexadecane production by covering the active Ru (0001) surface. The knowledge presented in this work has significance not just for a fundamental understanding of strong carbon-carbon σ bond scission but also for practical biomass conversion to fuels and chemical feedstocks.
- Di, Lu,Yao, Sikai,Li, Mengru,Wu, Guangjun,Dai, Weili,Wang, Guichang,Li, Landong,Guan, Naijia
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p. 7199 - 7207
(2015/12/11)
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- NMR-based molecular ruler for determining the depth of intercalants within the lipid bilayer. Part III: Studies on keto esters and acids
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The development of "molecular rulers" would allow one to quantitatively locate the penetration depth of intercalants within lipid bilayers. To this end, an attempt was made to correlate the 13C NMR chemical shift of polarizable "reporter" carbons (e.g., carbonyls) of intercalants within DMPC liposomal bilayers - with the polarity it experiences, and with its Angstrom distance from the interface. This requires families of molecules with two "reporter carbons" separated by a known distance, residing at various depths/polarities within the bilayer. For this purpose, two homologous series of dicarbonyl compounds, methyl n-oxooctadecanoates and the corresponding n-oxooctadecanoic acids (n = 4-16), were synthesized. To assist in assignment and detection several homologs in each system were prepared 13C-enriched in both carbonyls. Within each family, the number of carbons and functional groups remains the same, with the only difference being the location of the second ketone carbonyl along the fatty acid chain. Surprisingly, the head groups within each family are not anchored near the lipid-water interface, nor are they even all located at the same depth. Nevertheless, using an iterative best fit analysis of the data points enables one to obtain an exponential curve. The latter gives substantial insight into the correlation between polarity (measured in terms of the Reichardt polarity parameter, ET(30)) and penetration depth into the liposomal bilayer. Still missing from this curve are data points in the moderate polarity range.
- Afri, Michal,Alexenberg, Carmit,Aped, Pinchas,Bodner, Efrat,Cohen, Sarit,Ejgenburg, Michal,Eliyahu, Shlomi,Gilinsky-Sharon, Pessia,Harel, Yifat,Naqqash, Miriam E.,Porat, Hani,Ranz, Ayala,Frimer, Aryeh A.
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p. 105 - 118
(2015/02/19)
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- Oxidative coupling reactions of grignard reagents with nitrous oxide
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Catalysis with laughing gas: N2O in combination with transition-metal catalysts allow the oxidative homo- and cross-coupling of Grignard reagents. The reactions can be performed under mild conditions despite the inert character of N2O. Copyright
- Kiefer, Gregor,Jeanbourquin, Loic,Severin, Kay
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supporting information
p. 6302 - 6305
(2013/07/19)
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- Dilithium tetrachlorocuprate(II) catalyzed oxidative homocoupling of functionalized grignard reagents
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An efficient procedure is described for the oxidative homocoupling of functionalized Grignard reagents using a catalytic amount of dilithium tetrachlorocuprate(II) (CuLi2Cl4) in the presence of pure oxygen gas. This method is applied successfully to a variety of aryl, heteroaryl, alkyl, alkenyl and alkynyl halides, which are converted into the corresponding homocoupled products in good to excellent yields. Georg Thieme Verlag Stuttgart · New York.
- Hua, Si-Kai,Hu, Qiu-Peng,Ren, Jiangmeng,Zeng, Bu-Bing
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p. 518 - 526
(2013/03/29)
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- Copper-catalyzed cross-coupling reaction of organoboron compounds with primary alkyl halides and pseudohalides
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Non-activated alkyl electrophiles, including alkyl iodides, bromides, tosylates, mesylates, and even chlorides, underwent copper-catalyzed cross-coupling with aryl boron compounds and alkyl 9-BBN reagents (see scheme; 9-BBN=9-borabicyclo[3.3.1]nonane). The reactions proceed with practically useful reactivities and thus complement palladium- and nickel-catalyzed Suzuki-Miyaura coupling reactions of alkyl halides.
- Yang, Chu-Ting,Zhang, Zhen-Qi,Liu, Yu-Chen,Liu, Lei
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p. 3904 - 3907
(2011/05/15)
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- Efficient heterogeneous dual catalyst systems for alkane metathesis
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A fully heterogeneous and highly efficient dual catalyst system for alkane metathesis (AM) has been developed. The system is comprised of an alumina-supported iridium pincer catalyst for alkane dehydrogenation/olefin hydrogenation and a second heterogeneous olefin metathesis catalyst. The iridium catalysts bear basic functional groups on the aromatic backbone of the pincer ligand and are strongly adsorbed on Lewis acid sites on alumina. The heterogeneous systems exhibit higher lifetimes and productivities relative to the corresponding homogeneous systems as catalyst/catalyst interactions and bimolecular decomposition reactions are inhibited. Additionally, using a two-pot device, the supported Ir catalysts and metathesis catalysts can be physically separated and run at different temperatures. This system with isolated catalysts shows very high turnover numbers and is selective for the formation of high molecular weight alkanes.
- Huang, Zheng,Rolfe, Eleanor,Carson, Emily C.,Brookhart, Maurice,Goldman, Alan S,El-Khalafy, Sahar H.,Roy MacArthur, Amy H.
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experimental part
p. 125 - 135
(2010/06/20)
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- Glassy carbon modified by a silver-palladium alloy: cheap and convenient cathodes for the selective reductive homocoupling of alkyl iodides
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Micrometer-thick layers of silver-palladium alloy were elaborated in order to modify the surface of glassy carbon electrodes. Such a surface modification can be readily achieved via a preliminary silver galvanostatic deposit onto carbon followed by a 'palladization' step, thanks to a simple immersion in acidic PdII-based solutions producing a displacement reaction. The as-prepared metallic interfaces exhibit outstanding catalytic capabilities especially in the cleavage of carbon-halogen bonds while being chemically/electrochemically quite stable and relatively inexpensive. More specifically, the use of such glassy carbon/Ag-Pd electrodes in dimethylformamide (DMF) containing tetraalkylammonium salts (TAA+X-) makes the one-electron reductions of primary alkyl iodides possible; this reduction leads to the formation of homodimers in high yields. Formation of a free radical as transient resulted from the homocoupling reaction.
- Poizot, Philippe,Jouikov, Viatcheslav,Simonet, Jacques
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body text
p. 822 - 824
(2009/05/07)
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- Process for hydrogenation of carboxylic acids and derivatives to hydrocarbons
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A process for hydrogenating a carboxylic acid and/or derivative thereof having a carboxylate group represented by the general formula R1COO-, which process comprises feeding hydrogen and the carboxylic acid and/or derivative thereof to a reactor and maintaining conditions within the reactor such that hydrogen reacts with the carboxylic acid and/or derivative thereof to produce a product stream comprising carbon dioxide, carbon monoxide, methane and hydrocarbons represented by general formulae R1H and R1CH3, characterised in that the molar ratio of R1H : R1CH3 is above a pre-determined value and/or the mole ratio of the sum of carbon dioxide, carbon monoxide and methane to carboxylate groups is above a pre-determined value.
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Page/Page column 7-8
(2008/06/13)
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- METHOD FOR PRODUCING BIO-FUEL THAT INTEGRATES HEAT FROM CARBON-CARBON BOND-FORMING REACTIONS TO DRIVE BIOMASS GASIFICATION REACTIONS
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A low-temperature catalytic process for converting biomass (preferably glycerol recovered from the fabrication of bio-diesel) to synthesis gas (i.e., H2/CO gas mixture) in an endothermic gasification reaction is described. The synthesis gas is used in exothermic carbon-carbon bond-forming reactions, such as Fischer-Tropsch, methanol, or dimethylether syntheses. The heat from the exothermic carbon-carbon bond-forming reaction is integrated with the endothermic gasification reaction, thus providing an energy-efficient route for producing fuels and chemicals from renewable biomass resources.
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Page/Page column 13
(2008/06/13)
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- METHOD FOR THE PRODUCTION OF PRIMARY LONG-CHAIN ALCOHOLS
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The invention relates to a method for the production of linear long-chain alcohols with 20 to 40 carbon atoms by means of a growth reaction with ethylene on aluminium compounds.
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Page/Page column 8-9
(2010/02/15)
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- Sex pheromone and related compounds in the Ishigaki and Okinawa strains of the tussock moth Orgyia postica (Walker) (Lepidoptera: Lymantriidae)
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Two distinct electroantennographycally active (EAG-active) components, A and B, and a weakly active component C were found in a solvent extract from virgin females of the Ishigaki strain of the tussock moth, Orgyia postica (Walker). Components A, B, and C were found in the extract of the females at 4.0, 0.5, and 4.0 ng/female respectively. Components A, B, and C were identified as (6Z,9Z,11S,12S)-11,12-epoxyhenicosa-6,9-diene [(11S,12S)-1: posticlure], (6Z)-henicos-6-en-11-one (2), and (6Z,9Z)-henicosa-6,9-diene (3), respectively. Component B was absent in the extract from the Okinawa strain, in which components A and C were present at 2.0 and 1.5 ng/female respectively. (11S,12S)-1 and the racemic mixture showed attractiveness for both the Okinawa and Ishigaki strains, whereas (11R,12R)-1 did not. The addition of 2 significantly reduced the trap catches with (11S,12S)-1 on the Okinawa strain which lacked 2, while there was no significant inhibitory effect on the Ishigaki strain. The addition of 3 to (11S,12S)-1 did not significantly affect trap catches at Ishigaki or Okinawa. This confirmed that the attractant pheromone of O. postica of the Ishigaki strain is also (11S,12S)-1.
- Wakamura, Sadao,Arakaki, Norio,Yamamoto, Masanobu,Hiradate, Syuntaro,Yasui, Hiroe,Kinjo, Kunio,Yasuda, Tetsuya,Yamazawa, Hiroyuki,Ando, Tetsu
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p. 957 - 965
(2008/02/03)
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- Hydrogenation versus hydrogenolysis with a safe, selective and reusable catalyst: Palladium black on Teflon
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Palladium black deposit is obtained by reduction and metallization of the Teflon polymer surface of magnetic stirring bars. These stirring bars can be used to perform selective hydrogenation of olefins and acetylenic compounds whilst hydrogenolysis is not observed. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2005.
- Belotti, Damien,Cantagrel, Guillaume,Combellas, Catherine,Cossy, Janine,Kanoufi, Frederic,Nunige, Sandra
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p. 761 - 764
(2007/10/03)
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- Semivolatile and volatile compounds in combustion of polyethylene
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The evolution of semivolatile and volatile compounds in the combustion of polyethylene (PE) was studied at different operating conditions in a horizontal quartz reactor. Four combustion runs at 500 and 850°C with two different sample mass/air flow ratios and two pyrolytic runs at the same temperatures were carried out. Thermal behavior of different compounds was analyzed and the data obtained were compared with those of literature. It was observed that α,ω-olefins, α-olefins and n-paraffins were formed from the pyrolytic decomposition at low temperatures. On the other hand, oxygenated compounds such as aldehydes were also formed in the presence of oxygen. High yields were obtained of carbon oxides and light hydrocarbons, too. At high temperatures, the formation of polycyclic aromatic hydrocarbons (PAHs) took place. These compounds are harmful and their presence in the combustion processes is related with the evolution of pyrolytic puffs inside the combustion chamber with a poor mixture of semivolatile compounds evolved with oxygen. Altogether, the yields of more than 200 compounds were determined. The collection of the semivolatile compounds was carried out with XAD-2 adsorbent and were analyzed by GC-MS, whereas volatile compounds and gases were collected in a Tedlar bag and analyzed by GC with thermal conductivity and flame ionization detectors.
- Font, Rafael,Aracil, Ignacio,Fullana, Andrés,Conesa, Juan A.
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p. 615 - 627
(2007/10/03)
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- Formation of aldehydes and ketones via reduction of alkyl monohalides by electrogenerated nickel(I) salen in dimethylformamide in the presence of water, oxygen, and light
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Addition of a stoichiometric amount of a primary alkyl monohalide (1-bromooctane) to a solution of electrogenerated nickel(I) salen in dimethylformamide containing water, followed by irradiation with a xenon arc lamp and brief exposure to air, results in the formation of an aldehyde (1-octanal). Analogous experiments with a secondary alkyl monohalide (2-bromohexane) afford a ketone. Other products are alkanes, alkenes, and dimers that arise from classic radical coupling and disproportionation of alkyl radicals.
- Vanalabhpatana, Parichatr,Peters, Dennis G.
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p. 3245 - 3247
(2007/10/03)
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- A method for palladium-catalyzed cross-couplings of simple alkyl chlorides: Suzuki reactions catalyzed by [Pd2(dba)3]/PCy3
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The window of reactivity is relatively narrow in the first Suzuki cross-coupling of alkyl chlorides with alkyl 9-borabicyclo[3.3.1]nonane (9-BBN) derivatives catalyzed by [Pd2(dba)3] [Eq. (1); dba = (E,E)-dibenzylideneacetone]: whereas good yields are obtained with the ligand tricyclohexylphosphane for ligands that are appreciably larger or smaller, essentially no coupling is observed. As the conditions are compatible with a variety of functional groups, this method introduces a new class of substrates into the family of potential partners in palladium-catalyzed cross-coupling reactions.
- Kirchhoff, Jan H.,Dai, Chaoyang,Fu, Gregory C.
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p. 1945 - 1947
(2007/10/03)
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- Semi-volatile and particulate emissions from the combustion of alternative diesel fuels
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Motor vehicle emissions are a major anthropogenic source of air pollution and contribute to the deterioration of urban air quality. In this paper, we report results of a laboratory investigation of particle formation from four different alternative diesel fuels, namely, compressed natural gas (CNG), dimethyl ether (DME), biodiesel, and diesel, under fuelrich conditions in the temperature range of 800-1200°C at pressures of approximately 24 atm. A single pulse shock tube was used to simulate compression ignition (CI) combustion conditions. Gaseous fuels (CNG and DME) were exposed premixed in air while liquid fuels (diesel and biodiesel) were injected using a high-pressure liquid injector. The results of surface analysis using a scanning electron microscope showed that the particles formed from combustion of all four of the above-mentioned fuels had a mean diameter less than 0.1 μm. From results of gravimetric analysis and fuel injection size it was found that under the test conditions described above the relative particulate yields from CNG, DME, biodiesel, and diesel were 0.30%, 0.026%, 0.52%, and 0.51%, respectively. Chemical analysis of particles showed that DME combustion particles had the highest soluble organic fraction (SOF) at 71%, followed by biodiesel (66%), CNG (38%) and diesel (20%). This illustrates that in case of both gaseous and liquid fuels, oxygenated fuels have a higher SOF than non-oxygenated fuels. Motor vehicle emissions are a major anthropogenic source of air pollution and contribute to the deterioration of urban air quality. In this paper, we report results of a laboratory investigation of particle formation from four different alternative diesel fuels, namely, compressed natural gas (CNG), dimethyl ether (DME), biodiesel, and diesel, under fuelrich conditions in the temperature range of 800-1200°C at pressures of approximately 24 atm. A single pulse shock tube was used to simulate compression ignition (CI) combustion conditions. Gaseous fuels (CNG and DME) were exposed premixed in air while liquid fuels (diesel and biodiesel) were injected using a high-pressure liquid injector. The results of surface analysis using a scanning electron microscope showed that the particles formed from combustion of all four of the above-mentioned fuels had a mean diameter less than 0.1 μm. From results of gravimetric analysis and fuel injection size it was found that under the test conditions described above the relative particulate yields from CNG, DME, biodiesel, and diesel were 0.30%, 0.026%, 0.52%, and 0.51%, respectively. Chemical analysis of particles showed that DME combustion particles had the highest soluble organic fraction (SOF) at 71%, followed by biodiesel (66%), CNG (38%) and diesel (20%). This illustrates that in case of both gaseous and liquid fuels, oxygenated fuels have a higher SOF than non-oxygenated fuels.
- Sidhu, Sukh,Graham, John,Striebich, Richard
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p. 681 - 690
(2007/10/03)
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- Bruchins - Mitogenic 3-(hydroxypropanoyl) esters of long chain diols from weevils of the bruchidae
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Mono- and bis 3-(hydroxypropanoyl) esters of long chain, unsaturated diols have been isolated and identified from two genera of the family Bruchidae, and have been shown to be responsible for the mitogenic activity observed on pea pods resulting from oviposition by the pea weevil, Bruchus pisorum. The mitogenic compounds have been characterized and synthesized.
- Oliver, James E,Doss, Robert P,Williamson, R.Thomas,Carney, John R,DeVilbiss, E.David
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p. 7633 - 7641
(2007/10/03)
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- Fine particle and gaseous emission rates from residential wood combustion
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Residential wood combustion emissions were analyzed to determine emission rates and to develop chemical emissions profiles that represent the appliances and woods typically used in wood-burning-communities. Over 350 elements, inorganic compounds, and organic compounds were quantified. A range of 4-9 g/kg dry fuel of particulate matter(a dilution stack sampler equipped with a 2.5-μm particle selective cyclone. Emissions were diluted 20-70 times, cooled to ambient temperature, and allowed 80 s for condensation prior to collection. Wood type, wood moisture, burn rate, and fuel load were varied for different experiments. Fine particle and se mivolatile organic compounds were collected on filter/PUF/XAD/PUF cartridges. Inorganic samples and mass were collected on Teflon and quartz filters. Volatile organic carbon compounds were trapped with Tenax (C8- C20), canister (C2-C12), and 2,4-dinitrophenylhydrazine impregnated cartridges (carbonyl compounds). Analysis of particle and semivolatile organic species was conducted by gas chromatography/mass spectrometry. Teflon filters were analyzed for mass by gravimetry, trace elements were analyzed by X-ray fluorescence and ammonium was analyzed by automated colorimetry. Quartz filters were analyzed for organic and elemental carbon by thermal/optical reflectance, and forts were analyzed by ion chromatography. Select quartz filters were analyzed by accelerator mass spectrometry for carbon-12 and carbon-14 abundance. Canister and Tenax samples were analyzed by gas chromatography with a flame ionization detector, and carbonyl compounds were analyzed by high-performance liquid chromatography. Residential wood combustion emissions were analyzed to determine emission rates and to develop chemical emissions profiles that represent the appliances and woods typically used in wood-burning communities. Over 350 elements, inorganic compounds, and organic compounds were quantified. A range of 4-9 g/kg dry fuel of particulate matter (a dilution stack sampler equipped with a 2.5-μm particle selective cyclone. Emissions were diluted 20-70 times, cooled to ambient temperature, and allowed 80 s for condensation prior to collection. Wood type, wood moisture, burn rate, and fuel load were varied for different experiments. Fine particle and semivolatile organic compounds were collected on filter/PUF/XAD/PUF cartridges. Inorganic samples and mass were collected on Teflon and quartz filters. Volatile organic carbon compounds were trapped with Tenax (C8-C20), canister (C2-C12), and 2,4-dinitrophenylhydrazine impregnated cartridges (carbonyl compounds). Analysis of particle and semivolatile organic species was conducted by gas chromatography/mass spectrometry. Teflon filters were analyzed for mass by gravimetry, trace elements were analyzed by X-ray fluorescence, and ammonium was analyzed by automated colorimetry. Quartz filters were analyzed for organic and elemental carbon by thermal/optical reflectance, and ions were analyzed by ion chromatography. Select quartz filters were analyzed by accelerator mass spectrometry for carbon-12 and carbon-14 abundance. Canister and Tenax samples were analyzed by gas chromatography with a flame ionization detector, and carbonyl compounds were analyzed by high-performance liquid chromatography.
- Mcdonald, Jacob D.,Zielinska, Barbara,Fujita, Eric M.,Sagebiel, John C.,Chow, Judith C.,Watson, John G.
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p. 2080 - 2091
(2007/10/03)
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- Scope and utility of a new soluble copper catalyst [CuBr-LiSPh-LiBr-THF]: A comparison with other copper catalysts in their ability to couple one equivalent of a Grignard reagent with an alkyl sulfonate
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A mixture of equal amounts of CuBr-SMe2, LiBr, and LiSPh in THF at 0°C furnished a new soluble copper catalyst that was highly efficient at coupling primary, secondary, tertiary, aryl, vinyl, and allylic Grignard reagents to primary tosylates and primary Grignard reagents to secondary tosylates and mesylates, all with the use of only 1 equiv of Grignard reagent. The new catalyst was shown to be much more reactive than copper catalysts CuBr and Li2CuCl4 and more efficient in the transference of secondary and tertiary alkyl groups than lower order cuprates (Gilman reagents) and demonstrated more reactivity than the lower order cuprates with its ability to couple primary Grignard reagents to secondary sulfonates. The Grignard reagent/catalyst system was compatible with an ester functionalized tosylate, thus proving to be more chemoselective than a Grignard reagent without the catalyst. The catalyst exhibited good reactivity below room temperature, and with the addition of 6% v/v of HMPA to the catalyst solution, excellent yields of coupled product were obtained within a 25-67°C temperature range. 1H NMR demonstrated that the catalyst solution consisted of several species that most likely were composed of copper ligated with thiophenol, THF, and LiBr in aggregated forms.
- Burns, Dennis H.,Miller, Jeffrey D.,Chan, Ho-Kit,Delaney, Michael O.
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p. 2125 - 2133
(2007/10/03)
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- Terminal chlorination of normal alkane hydrocarbons
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A terminally chlorinated normal alkane hydrocarbon is produced at high terminal selectivity, by adsorbing a normal alkane into a select zeolite and chlorinating the adsorbed alkane in the zeolite. The zeolite may be of a type having internal channels of diameter slightly larger than that of the alkane, and substantially no internal chambers, and may be selected from the pentasil family of zeolites. The chlorination reaction may be conducted under heating to enhance terminal selectivity even further, in many cases to levels approaching 100%.
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- FLUORINATION WITH XENON DIFLUORIDE, PART XXXV. REACTION WITH GRIGNARD REAGENTS
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Several Grignard reagents in diethyl ether solution readily react with xenon difluoride at room temperature, the complexity of the reaction course depending on the structure of the reagent.In all cases studied three main types of products, i.e. 1-ethoxy-1-substituted ethane (2), reduced product (3) and dimeric product (4) are formed.In the case of dodecyl magnesium bromide (1a), 2-ethoxydodecane (2a), decane (3a) and eicosane (4a) formed represent 98percent of products formed, with 2percent of the reaction mixture containing at least up to seven unidentified products, while with benzyl magnesium bromide (1b), the three main products 2b, 3b, and 4b represent 80percent of the reaction mixture, the remaining 20percent containing up to nine products with benzyl bromide being the main side product.The complexity of the reaction increases even more in the case of phenyl magnesium bromide, where 2c, 3c and 4c represent only 70percent of products formed, the remaining 30percent consisting of up to 21 products with the following being identified: bromobenzene, bromobiphenyl, 1,1-bromo-1-phenylethane, α-bromo and α,α-dibromoacetophenone, and 1,1-diphenyl-2-bromoethene.
- Bregar, Zvonko,Stavber, Stojan,Zupan, Marko
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p. 187 - 194
(2007/10/02)
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- SYMMETRICAL AND UNSYMMETRICAL COUPLING OF ALKYL HALIDES MEDIATED BY GRIGNARD REACTION
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A simple method for extending the carbon chain via the coupling of alkyl or aryl halides has been developed.The versatility of this reaction has been demonstrated by symmetrical and unsymmetrical coupling of alkyl, alkenyl or alkynyl halides.
- Herendeen, Barbara L.,Bhatia, Suresh K.,Singh, Alok
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p. 2899 - 2908
(2007/10/02)
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- Electrosynthesis of symmetrical ketones from organic halides and carbon dioxide catalysed by 2,2'-bipyridine-nickel complexes
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The electrochemical reduction of 1 2,2'-bipyridine-nickel complex, in the presence of carbon dioxide in N-methylpyrrolidone or dimethylformamide as solvent gives the corresponding nickel(0) complex associated with two molecules of CO.Oxidative addition of an alkyl halide to this complex, followed by an internal CO shift and reductive elimination, leads to the formation of a symmetrical ketone in high yield along with nickel(II), whereas aryl or vinyl halides mainly give acyl derivatives.The nickel(0) species is electrochemically regenerated, thus giving rise to an efficient catalytic process.The possible mechanism of these reactions is discussed
- Garnier, L.,Rollin, Y.,Perichon, J.
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p. 347 - 358
(2007/10/02)
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- IDENTIFICATION OF THE BY-PRODUCTS OF ANODIC COUPLING BETWEEN ERUCIC AND PROPIONIC ACIDS AND BETWEEN OLEIC AND HEPTANOIC ACIDS, USING GAS CHROMATOGRAPHY-MASS SPECTROMETRY AND INFRARED SPECTROSCOPY
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A method is described as the simplest way for the synthesis of (Z)-9-tricosene, the sex pheromone of the housefly.The mixture of prodicts obtained on repeating the title syntheses appeared to be much more complex than described previously.The following by-products were identified using the GC/MS method: hydrocarbons with a straight chain - saturated C8 to C23, unsaturated C13 to C24; the dienes C20 and C21; and the methyl esters of fatty acids C7 to C22 (depending on the reaction path).In the products of the anodic coupling of erucic and propionic acids considerable amounts of high-molecular compounds were formed.The non-reported new compounds with molecular weights of 584 and 614 were formed in addition to the excepted 9,33-dotetracontadiene (m.w. 586).Their structures were elucidated by mass and ir spectroscopy as 9,20,33-dotetracontatriene (m.w. 584) and 9,34-tritetracontadien-21-one (m.w. 614).Mechanism of the formation of the by-products are proposed.
- Konopski, Leszek,Polec, Iwona
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p. 409 - 422
(2007/10/02)
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- Action of Alkylmagnesium and Alkyllithium Reagents on Some Quaternary Hydrazonium Salts
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Benzophenone N-methyl-N,N-pentane-1,5-diylhydrazonium iodide (1a) and its p,p'-dichloro and p,p'-dimethoxy analogues undergo loss of CH3I in boiling ethyl ether or THF, but the fluoroborates are stable.The complexes formed from 1 and Grignard reagents do not undergo incorporation of deuterium when they are hydrolyzed with D2O.When 1 and analogues are treated with propyl- and decylmagnesium bromide, the corresponding alkane, alkene, and bialkyl are produced, facts imply formation of alkyl radicals by a single-electron-transfer process.With all alkyl Grignard reagents studied, the overwhelming reaction is reductive cleavage of the N,N bond to form imines unsubstituted on nitrogen; no N-alkyl imines were detected.Small amounts of 1,1-diarylalkylamines, formed about 2percent of benzhydrylamine in reaction with 1a.Sodium cyanide reacted with the tetrafluoroborate analogue of 1a to form acetonitrile by demethylation; neither addition nor reduction was detected.Sodium azide behaved analogously.
- Smith, Peter A.S.,Messing, Calvin R.
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p. 2959 - 2965
(2007/10/02)
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- H/D ISOTOPE EFFECT IN γ-IRRADIATED C10H22/C10D22 MIXTURES AT 4 K DEDUCED BY STUDYING DIMERIC PRODUCTS BY GAS CHROMATOGRAPHY
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The dimer products formed upon γ-rradiation at 4 K of n-decane-d22 doped with 20percent n-decane-h22 have been examined by means of capillary GLC coupled with mass spectrometry.Analysis of the results indicates that protiated alkyl radicals are selectively formed.This confirms the data obtained by radiolysis at 77 K.The selective abstraction of hydrogen from a C-H bond on the solute molecules by the attack of D atoms which are formed by the radiolysis, occurs at 77 K.However, at 4 K, data from IWASAKI suggest an other explanation.The primary process is not selective but conversion of deuterated to protiated alkyl radicals takes place at 200 K.
- Tilquin, B.
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- Regioselective Functionalization of Nonactivated CH-Bonds, 4. -Photoreactions of Amphiphilic Derivatives of Benzophenonecarboxylic Acid and Myristic Acid Derivatives in Micelles and Bilayers
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Amphiphilic derivatives of benzophenonecarboxylic acid and myristic acid in micelles, vesicles, and multilamellar aggregates were photochemically converted into tertiary alcohols, the workup of which yielded mixtures of the isomeric ketomyristic acid methyl esters 5.A slightly increased but none the less low selectivity was found in bilayers in comparison with micelles.Various amphiphilic head groups shifted the center of attack.Low total yields, especially in bilayers, can be attributed to a predominant reaction between the benzophenone substituents.By preparation of the corresponding reference compounds it could be demonstrated that benzhydrols (8a-d) or benzpinacols (9a-c) are not formed in this unexpected reaction.
- Gogoll, Adolf,Schaefer, Hans J.
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p. 597 - 606
(2007/10/02)
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- SELECTIVE MIXED COUPLING OF CARBOXYLIC ACIDS (I). - ELECTROLYSIS, THERMOLYSIS AND PHOTOLYSIS OF UNSYMMETRICAL DIACYL PEROXIDES WITH ACYCLIC AND CYCLIC ALKYL GROUPS
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14 unsymmetrical diacyl peroxides (R1CO2-O2CR2 with R1: undecyl; R2: e.g. methyl, propyl, pentyl, nonyl, 2-methylpropyl, 2-propyl, 2-pentyl, cyclopropyl, cyclobutyl, cyclohexyl) are prepared in 85 to 92 percent yield.Square pulse electrolysis of dodecanoyl octanoyl peroxide (1i) affords the unsymmetrical coupling product octadecane (4) in poor yield and selectivity.Thermolysis or photolysis in solution produces preferentially 4, but also considerable amounts of disproportionation products.At -78 deg C the neat peroxides are photolysed selectively to the mixed dimers.With straight chain and β-branched alkyl groups high yields are obtained (63 - 76 percent), with cycloalkyl groups medium yields (42 - 56 percent), and with α-branched diacyl peroxides moderate yields (20 - 33 percent).A comparison of the mixed Kolbe-electrolysis with the low temperature photolysis of the neat peroxide demonstrates the superiority of the latter method in small scale conversion with regard to yield and selectivity.
- Feldhues, Michael,Schaefer, Hans J.
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p. 4195 - 4212
(2007/10/02)
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- Bifunctional compounds from reaction of alkoxy hydroperoxides with metal salts
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Alkoxy hydroperoxides, obtained by ozonizing olefins in alcoholic solution, were treated with ferrous sulfate. C-C bond scission and radical formation was followed by dimerization of the radicals formed. Ozonides reacted similarly. Acyclic and cyclic olefins, including a cyclic enol ether, gave rise to a range of α,ω-disubstituted products in modest yields. By using ferric chloride, ω-chloro esters were obtained from the alkoxy hydroperoxides derived from olefinic esters.
- Cardinale,Laan,Van Der Steen,Ward
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p. 6051 - 6054
(2007/10/02)
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- SELECTIVE MIXED COUPLING OF CARBOXYLIC ACIDS VIA UNSYMMETRICAL DIACYL PEROXIDES BY ELECTROLYSIS, THERMOLYSIS AND PHOTOLYSIS
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Unsymmetrical diacyl peroxides are prepared in 85-92 percent yields.Their square pulse electrolysis affords unsymmetrical dimers in poor yield and selectivity.Whilst thermolysis or photolysis in solution produces high portions of disproportionation products, the photolysis of the neat peroxides at -78 deg C yields selectively 50-75 percent of the mixed dimers.
- Feldhues, Michael,Schaefer, Hans J.
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p. 433 - 436
(2007/10/02)
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- The Reductive Coupling of Organic Halide Using Hydrazine and a Palladium Amalgam Catalyst. I. The Preparation of Biaryls
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Iodoarenes could be converted to the corresponding biaryls in high yields by use of a catalytic amount of a palladium amalgam in place of a palladium-calcium carbonate catalyst in Busch's reaction.The 2,3'-isomer content in the bitolyls obtained by the homo-coupling of o-iodotoluene was 15percent when palladium was used, while it was 1percent when a palladium amalgam was used, and the latter was re-usable.The present method is further applicable to some iodoalkanes.
- Nakajima, Riichiro,Shintani, Yuji,Hara, Tadashi
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p. 1767 - 1768
(2007/10/02)
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