- Durch Bromirung ausgeloeste Umlagerung tertiaerer Allylalkohole: Der Einfluss eines Fluor-Substituent auf Reactionsgeschwindigkeit und reactionsverlauf
-
The allyl alcohol bearing a methyl and a t-butyl group at the hydroxylated position was found to undergo a rearrangement when treated with bromine (or N-bromosuccinimide) in an aqueous medium and to afford a product mixture containing two regioisomeric ketones and one oxirane.Introduction of an additional methyl group or a fluorine atom at the non-terminal olefinic center led to a more selective discrimination between potential migratory groups.As the result of an exclusive t-butyl shift only one product, a ketone, was formed in both cases.Whereas the reaction rate only was slightly affected by the additional methyl group, it was substantually decreased by the fluorine atom.
- Nagakura, Isao,Savary, Dang Ngoc-Hue,Schlosser, Manfred
-
-
Read Online
- SYNTHESE A L'AIDE DE SULFONE-XXV. SUBSTITUTION SUR DES SULFONES: L'ANION PHENYLSULFINATE COMME GROUPE PARTANT DANS LA SUBSTITUTION DES SULFONES ALLYLIQUES PAR DES REACTIFS DE GRIGNARD EN PRESENCE DE SELS DE CUIVRE
-
Displacement reactions of the sulphinate anion from sulfones by Grignard reagents with copper catalysis take place readily with allylic sulphones.The regio chemistry and stereochemistry of the reaction are discussed.
- Julia, Marc,Righini-Tapie, Anne,Verpeaux, Jean-Noel
-
-
Read Online
- Synthesis of 1-nonene from decanoic acid by polymer-bound palladium complexes
-
(PhCN)2PdCl2 or Pd(OAc)2 was immobilized on polyorganosiloxane bearing phosphine group as the support The catalytic activity of polymer-bound palladium complex revealed higher activity and selectivity than the homogeneous catalyst for the synthesis of 1-nonene from decanoic acid.
- Tanaka, Satoshi,Shimizu, Kenji,Yamamoto, Iwao
-
-
Read Online
- Gold nanocluster-catalyzed semihydrogenation: A unique activation pathway for terminal alkynes
-
We report high catalytic activity of ultrasmall spherical Au 25(SC2H4Ph)18 and rod-shaped Au 25(PPh3)10(C≡CPh)5X 2 (X = Br, Cl) nanoclusters supported on oxides for the semihydrogenation of terminal alkynes into alkenes with >99% conversion of alkynes and ~100% selectivity for alkenes. In contrast, internal alkynes cannot be catalyzed by such "ligand-on" Au25 catalysts; however, with "ligand-off" Au25 catalysts the internal alkynes can undergo semihydrogenation to yield Z-alkenes, similar to conventional gold nanoparticle catalysts. On the basis of the results, a unique activation pathway of terminal alkynes by "ligand-on" gold nanoclusters is identified, which should follow a deprotonation activation pathway via a R′-C≡C-[AunLm] (where L represents the protecting ligands on the cluster), in contrast with the activation mechanism on conventional gold nanocatalysts. This new activation mode is supported by observing the incorporation of deprotonated -C≡CPh as ligands on rod-shaped Au25(PPh3)10(C≡ CPh)5X2 nanoclusters under conditions similar to the catalytic reaction and by detecting the R′-C≡C-[Au n(SC2H4Ph)m] via FT-IR spectroscopy.
- Li, Gao,Jin, Rongchao
-
-
Read Online
- Fabrication of Ni3N nanorods anchored on N-doped carbon for selective semi-hydrogenation of alkynes
-
Nickel is a highly active catalyst for the semi-hydrogenation of alkynes. However, the low selectivity of the alkene product caused by the over-hydrogenation reaction on Ni has hindered its practical applications. In this work, we report a new nickel nitride (Ni3N)-catalyzed semi-hydrogenation of alkynes to the corresponding alkenes. The Ni3N nanorods were facilely fabricated via a direct pyrolysis of the solid mixture of nickel acetate tetrahydrate and melamine (Mlm). The Ni3N phase in the optimum catalyst (Ni3N/NC-6/5-550) is shown to be effective and stable in the semi-hydrogenation of alkynes, with a high yield and good selectivity for alkenes (Z/E ratios up to >99/1). Both terminal and internal alkynes bearing a broad scope of functional groups are readily converted into alkenes with good chemo- and stereoselectivity. Notably, it was found that the over-hydrogenation can be markedly suppressed even at high conversion of alkyne. Density functional theory (DFT) calculations reveal that the low interaction between the alkene product and the Ni3N might plays a critical role in the selectivity enhancement.
- Shi, Xiaozhen,Wen, Xin,Nie, Shilin,Dong, Jie,Li, Jingde,Shi, Yongqing,Zhang, Huiling,Bai, Guoyi
-
-
- A Method for preparing alpha-olefins from Biomass-derived fat and oil
-
The present invention relates to a method for preparing alpha-olefins from biomass-derived fats and oils. According to the preparation method, all of the various saturated or unsaturated fatty acids in the biomass-derived fats and oils can be prepared into alpha-olefins, and a conventional problem that the saturated fatty acids do not participate in a reaction or a mixture is generated due to polyunsaturated fatty acids can be solved. Thus, the present invention can be advantageously used to prepare alpha-olefins from biomass.
- -
-
Paragraph 0191-0202; 0224-0227
(2020/09/22)
-
- Method for catalytically oxidizing primary alcohol into corresponding carboxylic acid and simultaneously co-producing corresponding alpha olefin
-
The invention relates to a method for catalytically oxidizing primary alcohol into corresponding carboxylic acid and simultaneously co-producing corresponding alpha olefin. The method comprises the following steps: mixing primary alcohol shown as a substrate (I), a catalyst cobalt salt, a nitrogen-containing ligand and a solvent, refluxing and stirring for 4-48 hours in an oxygen or air atmospherewith a certain pressure, and distilling and separating the reacted liquid to obtain carboxylic acid shown as (II) and alpha olefin in a certain proportion. The cobalt salt catalyst used in the methodis cheap and easy to obtain, the used nitrogen-containing ligand is a commercial nitrogen-containing compound, the used oxidant is oxygen or air, the reaction condition is mild, and various primary alcohols can be converted into corresponding carboxylic acids and alpha olefins at a high conversion rate under the condition of low cost.
- -
-
Paragraph 0038-0039
(2020/12/30)
-
- CuPd Nanoparticles as a Robust Catalyst for Electrochemical Allylic Alkylation
-
An efficient CuPd nanoparticle (NP) catalyst (3 nm CuPd NPs deposited on carbon support) is designed for catalyzing electrochemical allylic alkylation in water/isopropanol (1:1 v/v) and 0.2 m KHCO3 solution at room temperature. The Pd catalysis was Pd/Cu composition-dependent, and CuPd NPs with a Pd/Cu ratio close to one are the most efficient catalyst for the selective cross-coupling of alkyl halides and allylic halides to form C?C hydrocarbons with product yields reaching up to 99 %. This NP-catalyzed electrochemical allylic alkylation expands the synthetic scope of cross-coupling reactions and can be further extended to other organic reaction systems for developing green chemistry electrosynthesis methods.
- Guo, Xuefeng,Lin, Honghong,Muzzio, Michelle,Pang, Huan,Shen, Mengqi,Sun, Shouheng,Wei, Kecheng,Williard, Paul,Yin, Zhouyang,Yu, Chao
-
supporting information
p. 15933 - 15936
(2020/07/04)
-
- Methylenation for Aldehydes and Ketones Using 1-Methylbenzimidazol-2-yl Methyl Sulfone
-
The methylenation reagent 1-methylbenzimidazol-2-yl methyl sulfone 2 reacts with various aldehydes and ketones in the presence of t-BuOK (room temperature, 1 h) in dimethylformamide to give the corresponding terminal alkenes generally in high yields. For sensitive substrates, the reaction is better carried out at low temperature using sodium hexamethyldisilazide in 1,2-dimethoxyethane. The byproduct is easily removed from the products, and the reaction conditions are mild and practical. Reagent 2 can be easily prepared from commercially available 2-mercaptobenzimidazole 5 in 95% yield without any expensive reagents.
- Ando, Kaori,Oguchi, Mai,Kobayashi, Takahisa,Asano, Haruka,Uchida, Nariaki
-
p. 9936 - 9943
(2020/09/04)
-
- Hydrogenation of hydrophobic substrates catalyzed by gold nanoparticles embedded in Tetronic/cyclodextrin-based hydrogels
-
Hydrogenation of alkenes, alkynes and aldehydes was investigated under biphasic conditions using Au nanoparticles (AuNP) embedded into combinations of α-cyclodextrin (α-CD) and a poloxamine (Tetronic90R4). Thermo-responsive AuNP-containing α-CD/Tetronic90R4 hydrogels are formed under well-defined conditions of concentration. The AuNP displayed an average size of ca. 7 nm and a narrow distribution, as determined by TEM. The AuNP/α-CD/Tetronic90R4 system proved to be stable over time. Upon heating above the gel-to-sol transition temperature, the studied catalytic system allowed hydrogenation of a wide range of substrates such as alkenes, alkynes and aldehydes under biphasic conditions. Upon repeated heating/cooling cycles, the Au NP/α-CD/Tetronic90R4 catalytic system could be recycled several times without a significant decline in catalytic activity.
- Chevry,Menuel,Léger,No?l,Monflier,Hapiot
-
p. 9865 - 9872
(2019/07/04)
-
- An Engineered Self-Sufficient Biocatalyst Enables Scalable Production of Linear α-Olefins from Carboxylic Acids
-
Fusing the decarboxylase OleTJE and the reductase domain of P450BM3 creates a self-sufficient protein, OleT-BM3R, which is able to efficiently catalyze oxidative decarboxylation of carboxylic acids into linear α-olefins (LAOs) under mild aqueous conditions using O2 as the oxidant and NADPH as the electron donor. The compatible electron transfer system installed in the fusion protein not only eliminates the need for auxiliary redox partners, but also results in boosted decarboxylation reactivity and broad substrate scope. Coupled with the phosphite dehydrogenase-based NADPH regeneration system, this enzymatic reaction proceeds with improved product titers of up to 2.51 g L-1 and volumetric productivities of up to 209.2 mg L-1 h-1 at low catalyst loadings (~0.02 mol%). With its stability and scalability, this self-sufficient biocatalyst offers a nature-friendly approach to deliver LAOs.
- Lu, Chen,Shen, Fenglin,Wang, Shuaibo,Wang, Yuyang,Liu, Juan,Bai, Wen-Ju,Wang, Xiqing
-
p. 5794 - 5798
(2018/06/01)
-
- Metal-Free Catalytic Reductive Cleavage of Enol Ethers
-
In contrast to the well-known reductive cleavage of the alkyl-O bond, the cleavage of the alkenyl-O bond is much more challenging especially using metal-free approaches. Unexpectedly, alkenyl-O bonds were reductively cleaved when enol ethers were reacted with Et3SiH and a catalytic amount of B(C6F5)3. Supposedly, this reaction is the result of a B(C6F5)3-catalyzed tandem hydrosilylation reaction and a silicon-assisted β-elimination. A mechanism for this cleavage reaction is proposed based on experiments and density functional theory (DFT) calculations.
- Chulsky, Karina,Dobrovetsky, Roman
-
supporting information
p. 6804 - 6807
(2018/11/02)
-
- A durable nanocatalyst of potassium-doped iron-carbide/alumina for significant production of linear alpha olefins via Fischer-Tropsch synthesis
-
Improvement of activity, selectivity, and stability of the catalyst used in Fischer-Tropsch synthesis (FTS) to produce targeted hydrocarbon products has been a major challenge. In this work, the potassium-doped iron-carbide/alumina (K-Fe5C2/Al2O3), as a durable nanocatalyst containing small iron-carbide particles (~ 10 nm), was applied to high-temperature Fischer-Tropsch synthesis (HT-FTS) to optimize the production of linear alpha olefins. The catalyst, suitable under high space velocity reaction conditions (14–36 N L gcat?1 h?1) based on the well-dispersed potassium as an efficient base promoter on the active iron-carbide surface, shows very high CO conversion (up to ~90%) with extremely high activity (1.41 mmolCO gFe?1 s?1) and selectivity for C5–C13 linear alpha olefins.
- Park, Ji Chan,Jang, Sanha,Rhim, Geun Bae,Lee, Jin Hee,Choi, Hyunkyoung,Jeong, Heon-Do,Youn, Min Hye,Lee, Dong-Wook,Koo, Kee Young,Kang, Shin Wook,Yang, Jung-Il,Lee, Ho-Tae,Jung, Heon,Kim, Chul Sung,Chun, Dong Hyun
-
p. 190 - 198
(2018/08/01)
-
- Ligand-free nickel-catalyzed semihydrogenation of alkynes with sodium borohydride: A highly efficient and selective process for: Cis -alkenes under ambient conditions
-
We report a low-cost and efficient catalytic system, involving in situ generated ligand-free Ni NPs, methanol and sodium borohydride, for the semihydrogenation of alkynes under ambient conditions. This catalytic system exhibits remarkably high activity, satisfactory cis-selectivity for internal alkynes, good stability and general applicability.
- Wen, Xin,Shi, Xiaozhen,Qiao, Xianliang,Wu, Zhilei,Bai, Guoyi
-
supporting information
p. 5372 - 5375
(2017/07/06)
-
- Effect of the presence of ionic liquid during the NiMoS bulk preparation in the transformation of decanoic acid
-
The impact of the presence and amount of [BMIM][NTf2] ionic liquid during the preparation of bulk NiMoS catalysts was investigated. It was clearly shown that these factors have a strong influence on both the morphology and specific surface area of the obtained NiMoS samples. Most interestingly the catalytic activity for the transformation of decanoic acid increased up to three times when IL was present during synthesis. In the same time, a greater selectivity towards hydrocarbons was observed. On the whole a clear relationship between catalytic activity, selectivity and NiMoS morphology was demonstrated. Consequently, it is possible to modify the morphology of the materials and impact the catalytic properties by changing the synthesis conditions.
- Leyral, Géraldine,Brillouet, Soizic,Rousseau, Julie,Richard, Frédéric,Mamede, Anne Sophie,Courthéoux, Laurence,Pradel, Annie,Ribes, Michel,Brunet, Sylvette
-
p. 120 - 132
(2017/01/11)
-
- Direct Olefination of Alcohols with Sulfones by Using Heterogeneous Platinum Catalysts
-
Carbon-supported Pt nanoparticles (Pt/C) were found to be effective heterogeneous catalysts for the direct Julia olefination of alcohols in the presence of sulfones and KOtBu under oxidant-free conditions. Primary alcohols, including aryl, aliphatic, allyl, and heterocyclic alcohols, underwent olefination with dimethyl sulfone and aryl alkyl sulfones to give terminal and internal olefins, respectively. Secondary alcohols underwent methylenation with dimethyl sulfone. Under 2.5 bar H2, the same reaction system was effective for the transformation of alcohol OH groups to alkyl groups. Structural and mechanistic studies of the terminal olefination system suggested that Pt0 sites on the Pt metal particles are responsible for the rate-limiting dehydrogenation of alcohols and that KOtBu may deprotonate the sulfone reagent. The Pt/C catalyst was reusable after the olefination, and this method showed a higher turnover number (TON) and a wider substrate scope than previously reported methods, which demonstrates the high catalytic efficiency of the present method. Olefination of alcohols: The first heterogeneous catalytic terminal and internal olefination of primary alcohols and methylenation of secondary alcohols with sulfones, a reusable carbon-supported Pt catalyst, and KOtBu is reported (see scheme).
- Hakim Siddiki,Touchy, Abeda Sultana,Kon, Kenichi,Shimizu, Ken-Ichi
-
p. 6111 - 6119
(2016/04/26)
-
- METHOD FOR PRODUCING ORGANIC COMPOUND
-
PROBLEM TO BE SOLVED: To provide a method of subjecting a compound having on one carbon atom a carbon atom constituting a carbon-carbon double bond and a functional group such as a hydroxyl group to a reductive reaction condition and producing an organic compound having the functional group substituted with a hydrogen atom. SOLUTION: There is provided a method for producing a compound represented by a formula (50) from a raw material compound represented by a formula (10). The method includes a step of irradiating a reaction system with light, the reaction system comprising the raw material compound, a hydrogen source compound, and a catalyst having a palladium component supported by a carrier containing titanium oxide. (R11 to R15 are a hydrogen atom, a hydrocarbon group having 1 to 40 carbon atoms which may have a cyclic structure or a derivative group thereof, or a heteroatom-containing group having 1 to 20 carbon atoms which may have a cyclic structure or a derivative group thereof; and R16 is a hydrogen atom, a hydrocarbon group having 1 to 40 carbon atoms or an acyl group having 1 to 20 carbon atoms which may have a cyclic structure, or -CH(CH2OH)2).) COPYRIGHT: (C)2015,JPO&INPIT
- -
-
Paragraph 0113-0115
(2018/10/16)
-
- Practical Methylenation Reaction for Aldehydes and Ketones Using New Julia-Type Reagents
-
A new Julia-type methylenation reagent, 1-methyl-2-(methylsulfonyl)benzimidazole (1e), reacts with a variety of aldehydes and ketones in the presence of either NaHMDS (-55 °C to rt) or t-BuOK (rt, 1 h) in DMF to give the corresponding terminal alkenes in high yields. The byproducts are easily removed, and the reaction conditions are mild and practical.
- Ando, Kaori,Kobayashi, Takahisa,Uchida, Nariaki
-
supporting information
p. 2554 - 2557
(2015/05/27)
-
- Microbial biosynthesis of medium-chain 1-alkenes by a nonheme iron oxidase
-
Aliphatic medium-chain 1-alkenes (MCAEs, ~10 carbons) are "drop-in" compatible next-generation fuels and precursors to commodity chemicals. Mass production of MCAEs from renewable resources holds promise for mitigating dependence on fossil hydrocarbons. An MCAE, such as 1-undecene, is naturally produced by Pseudomonas as a semivolatile metabolite through an unknown biosynthetic pathway. We describe here the discovery of a single gene conserved in Pseudomonas responsible for 1-undecene biosynthesis. The encoded enzyme is able to convert medium-chain fatty acids (C10-C14) into their corresponding terminal olefins using an oxygen-activating, nonheme iron-dependent mechanism. Both biochemical and X-ray crystal structural analyses suggest an unusual mechanism of β-hydrogen abstraction during fatty acid substrate activation. Our discovery unveils previously unidentified chemistry in the nonheme Fe(II) enzyme family, provides an opportunity to explore the biology of 1-undecene in Pseudomonas, and paves the way for tailored bioconversion of renewable raw materials to MCAE-based biofuels and chemical commodities.
- Rui, Zhe,Li, Xin,Zhu, Xuejun,Liu, Joyce,Domigan, Bonnie,Barr, Ian,Cate, Jamie H. D.,Zhang, Wenjun
-
p. 18237 - 18242
(2015/02/19)
-
- A one-pot tandem olefin isomerization/metathesis-coupling (ISOMET) reaction
-
A tandem catalytic reaction has been developed as part of a process to discover tungsten-based olefin metathesis catalysts that have a strong preference for terminal olefins over cis or trans internal isomers in olefin metathesis. This tandem isomerization/terminal olefin metathesis reaction (ISOMET) converts Cn trans internal olefins into C2n-2cis olefins and ethylene. This reaction is made possible with Ru-based "alkene zipper" catalysts, which selectively isomerize trans olefins to an equilibrium mixture of trans and terminal olefins, plus tungsten-based metathesis catalysts that react relatively selectively with terminal olefins to give Z homocoupled products. The most effective catalysts are W(NAr)(C3H6)(pyr)-(OHIPT) (Ar = 2,6-diisopropylphenyl; pyr = pyrrolide; OHIPT = O-2,6-(2,4,6-i-Pr3C6H2)2C6H3) and various [CpRu(P - N)(MeCN)]X (X-= [B(3,5-(CF3)2C6H3)4]-, PF6-, B(C6F5)4-) isomerization catalysts.
- Dobereiner, Graham E.,Erdogan, Gulin,Larsen, Casey R.,Grotjahn, Douglas B.,Schrock, Richard R.
-
p. 3069 - 3076
(2015/02/19)
-
- Copper-catalyzed alkyl-alkyl cross-coupling reactions using hydrocarbon additives: Efficiency of catalyst and roles of additives
-
Cross-coupling of alkyl halides with alkyl Grignard reagents proceeds with extremely high TONs of up to 1230000 using a Cu/unsaturated hydrocarbon catalytic system. Alkyl fluorides, chlorides, bromides, and tosylates are all suitable electrophiles, and a TOF as high as 31200 h-1 was attained using an alkyl iodide. Side reactions of this catalytic system, i.e., reduction, dehydrohalogenation (elimination), and the homocoupling of alkyl halides, occur in the absence of additives. It appears that the reaction involves the β-hydrogen elimination of alkylcopper intermediates, giving rise to olefins and Cu-H species, and that this process triggers both side reactions and the degradation of the Cu catalyst. The formed Cu-H promotes the reduction of alkyl halides to give alkanes and Cu-X or the generation of Cu(0), probably by disproportionation, which can oxidatively add to alkyl halides to yield olefins and, in some cases, homocoupling products. Unsaturated hydrocarbon additives such as 1,3-butadiene and phenylpropyne play important roles in achieving highly efficient cross-coupling by suppressing β-hydrogen elimination, which inhibits both the degradation of the Cu catalyst and undesirable side reactions.
- Iwasaki, Takanori,Imanishi, Reiko,Shimizu, Ryohei,Kuniyasu, Hitoshi,Terao, Jun,Kambe, Nobuaki
-
p. 8522 - 8532
(2015/01/08)
-
- An alternative mechanistic paradigm for the β-Z hydrosilylation of terminal alkynes: The role of acetone as a silane shuttle
-
The β-Z selectivity in the hydrosilylation of terminal alkynes has been hitherto explained by introduction of isomerisation steps in classical mechanisms. DFT calculations and experimental observations on the system [M(I)2{κ-C,C,O,O-(bis-NHC)}]BF4 (M=Ir (3 a), Rh (3 b); bis-NHC=methylenebis(N-2-methoxyethyl)imidazole-2-ylidene) support a new mechanism, alternative to classical postulations, based on an outer-sphere model. Heterolytic splitting of the silane molecule by the metal centre and acetone (solvent) affords a metal hydride and the oxocarbenium ion [R 3Si - O(CH3)2]+, which reacts with the corresponding alkyne in solution to give the silylation product [R 3Si - CHi£C - R]+. Thus, acetone acts as a silane shuttle by transferring the silyl moiety from the silane to the alkyne. Finally, nucleophilic attack of the hydrido ligand over [R3Si - CHi£C - R]+ affords selectively the β-(Z)- vinylsilane. The β-Z selectivity is explained on the grounds of the steric interaction between the silyl moiety and the ligand system resulting from the geometry of the approach that leads to β-(E)-vinylsilanes. Silanes catch the shuttle: An outer-sphere mechanism that explains the β-Z hydrosilylation of terminal alkynes based on the role of acetone as a silane shuttle is disclosed. Heterolytic splitting of the silane molecule by the metal centre and acetone affords a metal hydride and the oxocarbenium ion [R 3Si - O(CH3)2]+, which reacts with the alkyne in solution to give the silylation product [R3Si - CHi£C - R]+ (see figure).
- Iglesias, Manuel,Sanz Miguel, Pablo J.,Polo, Victor,Fernandez-Alvarez, Francisco J.,Perez-Torrente, Jesus J.,Oro, Luis A.
-
p. 17559 - 17566
(2014/01/06)
-
- Copper nanoparticle-catalyzed cross-coupling of alkyl halides with Grignard reagents
-
A cross-coupling reaction between alkyl bromides and chlorides and various Grignard reagents was carried out in the presence of commercially available copper or copper oxide nanoparticles as a catalyst and an alkyne additive. The catalytic system shows high activity, a broad scope, and good functional group tolerance.
- Kim, Ju Hyun,Chung, Young Keun
-
supporting information
p. 11101 - 11103
(2013/11/19)
-
- A novel iron complex for cross-coupling reactions of multiple C-Cl bonds in polychlorinated solvents with grignard reagents
-
A novel iron(III) complex (2) of a pincer ligand [1, N2,N6-bis(2,6- diisopropylphenyl)pyridine-2,6-dicarboxamide] was developed and used for remediation of polychlorinated solvents via sp3-sp3 coupling of Grignard reagents with C-Cl bonds. The use of an iron catalyst for such coupling reactions is highly desirable due to its greener and more economical nature. Complex 2 was characterized using various spectroscopic techniques: electrospray ionization mass spectrometer (ESI-MS, m/z 575.1), cyclic voltammetry (E 1/2, 0.03 V and ΔE, 0.97 V), and ultraviolet visible (UV/Vis) spectroscopic techniques. The iron(III) complex showed efficient activation of multiple C-Cl bonds and catalyzing C-C coupling of polychlorinated alkyl halides, such as dichloromethane (CH2Cl2), chloroform (CHCl3), and carbon tetrachloride (CCl4), with various Grignard reagents under ambient reaction conditions. Complex 2 showed exceptional activity with reactions approaching near completion in about 5 min. With the required catalyst loading as low as 0.2 mol%, considerably high turnover numbers (TON = 483) and turnover frequency (TOF = 5,800 h-1) were obtained. None of the products detected during the reaction contained any chlorine, indicating an efficient dechlorination method while synthesizing products of synthetic and commercial interest. Interestingly, the catalyst was capable of replacing all chlorine atoms in each polychlorinated solvent under the investigations with high conversion. Springer Science+Business Media, LLC 2012.
- Gartia, Yashraj,Pulla, Sharon,Ramidi, Punnamchandar,Farris, Carolina Costa,Nima, Zeid,Jones, Darin E.,Biris, Alexandru S.,Ghosh, Anindya
-
p. 1397 - 1404
(2013/01/15)
-
- Cross coupling reactions of multiple CCl bonds of polychlorinated solvents with Grignard reagent using a pincer nickel complex
-
The nickel(II) complex of a bulky pincer-type ligand, N,N′-bis(2,6- diisopropylphenyl)-2,6-pyridinedicarboxamido, was examined for sp 3-sp3 coupling of Grignard reagents with polychlorinated solvents. The nickel(II) complex catalyzed CC coupling of polychlorinated alkyl halides, such as dichloromethane (CH2Cl2), chloroform (CHCl3), and carbon tetrachloride (CCl4), with various Grignard reagents. The effective activation of multiple CCl bonds proceeded under ambient reaction conditions and within a short time (20 min). This catalyst displays the highest activity yet reported for this reaction type, with catalyst loading as low as 0.4 mol% and turnover frequency (TOF) as high as 724 h-1. The catalyst is capable of replacing all chlorine atoms with CC bond formations for all of the polychlorinated solvents under investigation. The catalytic process could prove to be an efficient method of remediation of toxic polychlorinated solvents while generating synthetically and commercially important chemicals.
- Gartia, Yashraj,Nasini, Udaya Bhasker,Ghosh, Anindya,Biswas, Abhijit,Stadler, Matthew
-
p. 322 - 327,6
(2020/07/30)
-
- Catalytic Conversion of Cellulose to Liquid Hydrocarbon Fuels by Progressive Removal of Oxygen to Facilitate Separation Processes and Achieve High Selectivities
-
Described is a method to make liquid chemicals, such as functional intermediates, solvents, and liquid fuels from biomass-derived cellulose. The method is cascading; the product stream from an upstream reaction can be used as the feedstock in the next downstream reaction. The method includes the steps of deconstructing cellulose to yield a product mixture comprising levulinic acid and formic acid, converting the levulinic acid to γ-valerolactone, and converting the γ-valerolactone to pentanoic acid. Alternatively, the γ-valerolactone can be converted to a mixture of n-butenes. The pentanoic acid so formed can be further reacted to yield a host of valuable products. For example, the pentanoic acid can be decarboxylated yield 1-butene or ketonized to yield 5-nonanone. The 5-nonanone can be hydrodeoxygenated to yield nonane, or 5-nonanone can be reduced to yield 5-nonanol. The 5-nonanol can be dehydrated to yield nonene, which can be dimerized to yield a mixture of C9 and C18 olefins, which can be hydrogenated to yield a mixture of alkanes. Alternatively, the nonene may be isomerized to yield a mixture of branched olefins, which can be hydrogenated to yield a mixture of branched alkanes. The mixture of n-butenes formed from γ-valerolactone can also be subjected to isomerization and oligomerization to yield olefins in the gasoline, jet and Diesel fuel ranges.
- -
-
Page/Page column 14
(2010/12/31)
-
- Nickel complexes of a pincer amidobis(amine) ligand: Synthesis, structure, and activity in stoichiometric and catalytic C-C bond-forming reactions of alkyl halides
-
The synthesis, properties, and reactivity of nickel(II) complexes of a newly developed pincer amidobis(amine) ligand (McNN2) are described. Neutral or cationic complexes [(MeNN2)NiX] (X = OTf (6), OC(O)CH3 (7), CH3CN (8), OMe (9)) were prepared by salt metathesis or chloride abstraction from the previously reported [( MeNN2)NiCl] (1). The Lewis acidity of the {( McNN2)Ni) fragment was measured by the 1H NMR chemical shift of the coordinated CH3CN molecule in 8. Electrochemical measurements on 1 and 8 indicate that the electron-donating properties of NN2 are similar to those of the analogous amidobis(phosphine) (pnp) ligands. The solid-state structures of 6-8 were determined and compared to those of 1 and [(MeNN2)NiEt] (3). In all complexes, the MeNN2 ligand coordinates to the NiII ion in a mer fashion, and the square-planar coordination sphere of the metal is completed by an additional donor. The coordination chemistry of MeNN 2 thus resembles that of other three-dentate pincer ligands, for example, pnp and arylbis(amine) (ncn). Reactions of 2 with alkyl monohalides, dichlorides, and trichlorides were investigated. Selective C-C bond formation was observed in many cases. Based on these reactions, efficient Kumada-Corriu-Tamao coupling of unactivated alkyl halides and alkyl Grignard reagents with 1 as the precatalyst was developed. Good yields were obtained for the coupling of primary and secondary iodides and bromides. Double C-C coupling of CH2Cl2 with alkyl Grignard reagents by 1 was also realized. The scope and limitations of these transformations were studied. Evidence was found for a radical pathway in Ni-catalyzed C-C cross-coupling reactions, which involves NiIl alkyl intermediates.
- Vechorkin, Oleg,Csok, Zsolt,Scopelliti, Rosario,Hu, Xile
-
experimental part
p. 3889 - 3899
(2009/12/26)
-
- Avoiding olefin isomerization during decyanation of alkylcyano α,ω-dienes: A deuterium labeling and structural study of mechanism
-
(Chemical Equation Presented) A two-step synthetic pathway involving decyanation chemistry for the synthesis of pure alkyl α,ω-dienes in quantitative yields is presented. Prior methodologies for the preparation of such compounds required 6-9 steps, sometimes leading to product mixtures resulting from olefin isomerization chemistry. This isomerization chemistry has been eliminated. Deuteration labeling and structural mechanistic investigations were completed to decipher this chemistry. Deuterium labeling experiments reveal the precise nature of this radical decyanation chemistry, where an alcohol plays the role of hydrogen donor. The correct molecular design to avoid competing intramolecular cyclization, and the necessary reaction conditions to avoid olefin isomerization during the decyanation process are reported herein.
- Rojas, Giovanni,Wagener, Kenneth B.
-
p. 4962 - 4970
(2008/12/20)
-
- Unsaturated fatty alcohol derivatives as a source of substituted allylzirconocene
-
(Chemical Equation Presented) From A to Z: Allylzirconocenes have been easily prepared in a one-pot procedure through a tandem allylic C-H activation-β-elimination reaction from unsaturated fatty alcohol and ether starting materials (see scheme). The reaction proceeds rapidly under mild condition and is insensitive to the length of the carbon tether between the double bond and the alcohol moiety.
- Chinkov, Nicka,Levin, Anat,Marek, Ilan
-
p. 465 - 468
(2007/10/03)
-
- PREPARATION OF BRANCHED ALIPHATIC ALCOHOLS USING COMBINED PROCESS STREAMS FROM A HYDROGENATION UNIT, A DEHYDROGENATION UNIT AND AN ISOMERIZATION UNIT
-
Systems and methods to produced branched aliphatic alcohols are described. Systems may include a hydrogenation unit, dehydrogenation unit, an olefin isomerization unit, a hydroformylation unit, and/or combinations thereof. Methods for producing branched aliphatic alcohols may include isomerization of olefins in a process stream. The isomerized olefins may be hydroformylated to produce aliphatic alcohols. After hydroformylation of the aliphatic alcohols, unreacted components from the hydroformylation process may be separated from the aliphatic alcohols products. The unreacted components from the hydroformylation process may be recycled back into the main process stream or sent to other processing units. Addition of multiple streams to the units may be performed to control reaction conditions in the units.
- -
-
Page/Page column 25-26
(2008/06/13)
-
- PREPARATION OF BRANCHED ALIPHATIC ALCOHOLS USING COMBINED PROCESS STREAMS FROM A DIMERIZATION UNIT AND AN ISOMERIZATION UNIT
-
Systems and methods to produced branched aliphatic alcohols are described. Systems may include an olefin dimerization unit, an olefin isomerization unit, a hydroformylation unit and/or combinations thereof. Methods for producing branched aliphatic alcohols may include isomerization of olefins in a process stream. The isomerized olefins may be hydroformylated to produce aliphatic alcohols. After hydroformylation of the aliphatic alcohols, unreacted components from the hydroformylation process may be separated from the aliphatic alcohols products. The unreacted components from the hydroformylation process may be recycled back into the main process stream or sent to other processing units. Addition of multiple streams to the units may be performed to control reaction conditions in the units.
- -
-
Page/Page column 28
(2008/06/13)
-
- PREPARATION OF BRANCHED ALIPHATIC ALCOHOLS USING COMBINED PROCESS STREAMS FROM A HYDROGENATION UNIT AND A DEHYDROGENATION-ISOMERIZATION UNIT
-
Systems and methods to produced branched aliphatic alcohols are described. Systems may include a hydrogenation unit, a dehydrogenation-isomerization unit, a hydroformylation unit and/or combinations thereof. Methods for producing branched aliphatic alcohols may include isomerization of olefins in a process stream. The isomerized olefins may be hydroformylated to produce aliphatic alcohols. After hydroformylation of the aliphatic alcohols, unreacted components from the hydroformylation process may be separated from the aliphatic alcohols products. The unreacted components from the hydroformylation process may be recycled back into the main process stream or sent to other processing units. Addition of multiple streams to the units may be performed to control reaction conditions in the units.
- -
-
Page/Page column 41-42
(2008/06/13)
-
- PREPARATION OF BRANCHED ALIPHATIC ALCOHOLS USING A PROCESS STREAM FROM A DEHYDROGENATION-ISOMERIZATION UNIT
-
Systems and methods to produced branched aliphatic alcohols are described. Systems may include a dehydrogenation-isomerization unit and a hydroformylation unit. Methods for producing branched aliphatic alcohols may include isomerization of olcfins in a process stream. The isomerized olefins may be hydroformylated to produce aliphatic alcohols. After hydroformylation of the aliphatic alcohols, unreacted components from the hydroformylation process may be separated from the aliphatic alcohols products. The unreacted components from the hydroformylation process may be recycled back into the main process stream or sent to other processing units. Addition of multiple streams to the dehydrogenation-isomerization unit and/or hydroformylation unit may be performed to control reaction conditions in the units.
- -
-
Page/Page column 42-43
(2008/06/13)
-
- PREPARATION OF BRANCHED ALIPHATIC ALCOHOLS USING A PROCESS STREAM FROM AN ISOMERIZATION UNIT WITH RECYCLE TO A DEHYDROGENATION UNIT
-
Systems and methods to produced branched aliphatic alcohols are described. Systems may include an olefin isomerization unit, a hydrofo rmylation unit, a dehydrogenation unit, and/or combinations thereof Methods for producing branched aliphatic alcohols may include isomerization of olefins in a process stream. The isomerized olefins may be hydroformylated to produce aliphatic alcohols. After hydroformylation of the aliphatic alcohols, unreacted components from the hydroformylation process may be separated from the aliphatic alcohols products. The unreacted components from the hydroformylation process may be recycled back into the main process stream or sent to other processing units. Addition of multiple streams to the units may be performed to control reaction conditions in the units
- -
-
Page/Page column 25-26
(2008/06/13)
-
- Synthesis of linear α-olefins via polyhomologation
-
Linear α-olefins (LAOs) of controlled molecular weight and low PDI were synthesized in high yield by the polyhomologation reaction of dimethylsulfoxonium methylide (1) with triallylborane (2). Following polymerization, propionic acid or trimethylamine N-oxide dihydrate (TAO) was used to afford α-vinyl-ω-methyl or α-vinyl-ω-hydroxy end-functionalized polymethylene, respectively. Controllable molecular weights up to 13 kDa were obtained by varying the initial monomer/catalyst ratio, and the resultant polymers had very narrow polydispersities (PDI n ≤ 36).
- Wagner, Carl E.,Rodriguez, Andrew A.,Shea, Kenneth J.
-
p. 7286 - 7291
(2007/10/03)
-
- Semivolatile and volatile compounds in combustion of polyethylene
-
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.
-
p. 615 - 627
(2007/10/03)
-
- Methods of preparing branched alkyl aromatic hydrocarbons
-
Systems and methods to produce branched alkyl aromatic hydrocarbons are described. Systems may include an olefin isomerization unit, an olefin dimerization unit, a dehydrogenation-isomerization unit, an alkylation unit, a dehydrogenation unit, a hydrogenation unit and/or combinations thereof. Methods for producing branched alkyl aromatic hydrocarbons may include isomerization of olefins in a process stream. The isomerized olefins may be used to alkylate aromatic hydrocarbons. After alkylation of the aromatic hydrocarbons, unreacted components from the alkylation process may be separated from the alkyl aromatic hydrocarbons. The unreacted components from the alkylation process may be recycled back into a process stream or sent to other processing units.
- -
-
-
- METHOD OF PREPARING BRANCHED ALKYL AROMATIC HYDROCARBONS USING A PROCESS STREAM PRODUCED FROM A HYDROGENATION AND DEHYDROGENATION-ISOMERIZATION OF OLEFINS
-
Systems and methods to produce branched alkyl aromatic hydrocarbons are described. Systems may include a hydrogenation unit, an olefin dehydrogenation-isomerization unit, an alkylation unit and a separation unit. Methods for producing branched alkyl aromatic hydrocarbons may include treatment of a process stream that with a hydrogenation unit followed by a dehydrogenation-isomerization unit. The produced olefins may be used to alkylate aromatic hydrocarbons to form branched alkyl aromatic hydrocarbons. After alkylation of the aromatic hydrocarbons, unreacted components from the alkylation process may be separated from the alkyl aromatic hydrocarbons. The unreacted components from the alkylation process may be recycled back into the main process stream or sent to other processing units.
- -
-
-
- METHOD OF PREPARING BRANCHED ALKYL AROMATIC HYDROCARBONS USING A PROCESS STREAM FROM A DEHYDROGENATION-ISOMERIZATION UNIT
-
Systems and methods to produce branched alkyl aromatic hydrocarbons are described. Systems may include an olefin dehydrogenation-isomerization unit, an alkylation unit and a separation unit. Methods for producing branched alkyl aromatic hydrocarbons may include treatment of a process stream that includes paraffins and olefins with a dehydrogenation-isomerization unit. The produced olefins may be used to alkylate aromatic hydrocarbons to form branched alkyl aromatic hydrocarbons. After alkylation of the aromatic hydrocarbons, unreacted components from the alkylation process may be separated from the alkyl aromatic hydrocarbons. The unreacted components from the alkylation process may be recycled back into the main process stream or sent to other processing units.
- -
-
-
- METHOD OF PREPARING BRANCHED ALKYL AROMATIC HYDROCARBONS USING A PROCESS STREAM FROM AN ISOMERIZATION UNIT
-
Systems and methods to produce branched alkyl aromatic hydrocarbons are described. Systems may include an isomerization unit, a dehydrogenation unit, an alkylation unit and separation unit. Methods for producing branched alkyl aromatic hydrocarbons may include isomerization of olefins in a process stream. The produced olefins may be used to alkylate aromatic hydrocarbons to form branched alkyl aromatic hydrocarbons. After alkylation of the aromatic hydrocarbons, unreacted components from alkylation process may be separated from the alkyl aromatic hydrocarbons. The unreacted components from the alkylation process may be recycled back into the main process stream or sent to other processing units
- -
-
-
- METHOD OF PREPARING BRANCHED ALKYL AROMATIC HYDROCARBONS USING COMBINED PPROCESS STREAMS PRODUCED FROM HYDROGENATION, DEHYDROGENATION, DIMERIZATION AND ISOMERIZATION OF OLEFINS
-
Systems and methods to produce branched alkyl aromatic hydrocarbons are described. Systems may include a hydrogenation unit, a dehydrogenation unit, an olefin dimerization unit, an isomerization unit, an alkylation unit and/or one or more separations unit. Methods for producing a branched alkyl aromatic hydrocarbons may include any combination of hydrogenation, dehydrogenation, dimerization and/or isomerization of olefms in a process stream. The produced olefins may be used to alkylate aromatic hydrocarbons to form branched alkyl aromatic hydrocarbons. After alkylation of the aromatic hydrocarbons, unreacted components from the alkylation process may be separated from the alkyl aromatic hydrocarbons. The unreacted components from the alkylation process may be recycled back into the main process stream or sent to other processing units.
- -
-
-
- METHOD OF PREPARING BRANCHED ALKYL AROMATIC HYDROCARBONS USING COMBINED PROCESS STREAMS FROM A DIMERIZATION UNIT AND AN ISOMERIZATION UNIT
-
Systems and methods to produce branched alkyl aromatic hydrocarbons are described. Systems may include an olefin dimerization unit, an isomerization unit, an alkylation unit, combinations thereof and/or one or more separations unit. A method for producing branched alkyl aromatic hydrocarbons may include combining process streams from dimerization and isomerization units to produce a mixed stream that includes olefins. The olefins in the mixed stream may be used to alkylate aromatic hydrocarbons to form branched alkyl aromatic hydrocarbons. After alkylation of the aromatic hydrocarbons, unreacted components from the alkylation process may be separated from the alkyl aromatic hydrocarbons. The unreacted components from the alkylation process may be recycled back into the main process stream or sent to other processing units.
- -
-
-
- Selective isomerization and linear dimerization of olefins using cobalt catalysts
-
Processes for the production of alpha-olefins, including dimerization and isomerization of olefins using a cobalt catalyst complex are provided herein. The olefins so produced are useful as monomers in further polymerization reactions and are useful as chemical intermediates.
- -
-
-
- Synthesis and transformations of metallacycles 28. Reactions of allenes with EtAlCl2 and Et2AlCl catalyzed by Ti and Zr complexes
-
Catalytic cycloalumination of allenes with EtAlCl2 in the presence of Ti or Zr complexes afforded methylidene- and alkyl(benzyl)idenealuminacyclopropanes and the corresponding aluminacyclopentanes, which were identified by analyzing the hydroly
- Ibragimov,Khafizova,Gil'fanova,Dzhemilev
-
p. 2255 - 2260
(2007/10/03)
-
- Olefin Cross-Metathesis as a Tool in Natural Product Degradation. The Stereochemistry of (+)-Falcarindiol
-
(Matrix Presented) There are conflicting reports in the literature concerning the absolute sterochemistry at C-3 of the common plant polyacetylene oxylipin (+)-falcarindiol. We have employed olefin cross-metathesis using Grubbs' second generation catalyst and ethylene gas to degrade falcarindiol to the symmetrical 1,9-decadiene-4,6-diyne-3,8-diol. The reaction is completely selective for net removal of the aliphatic side chain. Degradation of (+)-falcarindiol from Tetraplasandra hawaiiensis yields a meso product as shown by chiral HPLC. Hence, (+)-falcarindiol from this source has a (3R,8S)-configuration.
- Ratnayake, Anokha S.,Hemscheidt, Thomas
-
p. 4667 - 4669
(2007/10/03)
-
- Synthesis, characterisation and catalytic of Pd(II) and Ni(II) complexes with new cyclic α-diphenylphosphino-ketoimines. Crystal structure of 2,6-diisopropyl-N-(2-diphenylphosphino-cyclopentylidene)aniline and of 2,6-diisopropyl-N-(2-diphenylphosphino-cyclohexylidene)aniline
-
New cyclic α-diphenylphosphino-ketoimines have been synthesised by deprotonation of the corresponding imine and subsequent reaction with chlorodiphenylphosphine. The crystal structures of two of these compounds containing a cyclopentylidene and cyclohexylidene backbone are discussed. Reaction of these bidentate phosphorus-nitrogen (P∧N) ligands with (cod)Pd(CH3)Cl leads to neutral complexes of the general formula (P∧N)Pd(CH3)Cl which have been reacted with AgSbF6 to yield cationic complexes of formula [(P∧N)Pd(CH3)(NCCH3)]SbF6. Reaction of these ligands with (1,2-dimethoxyethane)NiBr2 yields neutral nickel(II) complexes that have been characterised by IR and elemental analysis. Cationic Pd(II) complexes as well as MAO-activated neutral nickel(II) complexes have been used as ethylene oligomerisation catalysts. The cationic palladium(II) complexes show a marked pressure dependence of TOF, with α-olefin fraction and Schulz-Flory α-values explainable in the light of the accepted mechanism for analogous complexes. By increasing the steric bulkiness of the substituent on the imine, or by using ligands with cyclohexylidene or cycloheptylidene backbone instead of cyclopentylidene, a drop in catalytic activity is observed. Nickel(II) complexes of the title ligands activated with MAO permit to confirm the latter conclusions. In comparison with palladium their use brings to comparable linearities but higher oligomerisation grades as well as α-olefin fraction. Cationic palladium(II) complexes are also active in the propene and 1-butene oligomerisation.
- Keim, Wilhelm,Killat, Stefan,Nobile, Cosimo F,Suranna, Gian Paolo,Englert, Ulli,Wang, Ruimin,Mecking, Stefan,Schr?der, Dirk Lucas
-
p. 150 - 171
(2007/10/03)
-
- The gas-phase oxidation of n-hexadecane
-
Since n-hexadecane or cetane is a reference fuel for the estimation of cetane numbers in diesel engines, a detailed chemical model of its gas-phase oxidation and combustion will help to enhance diesel performance and reduce the emission of pollutants at t
- Fournet,Battin-Leclerc,Glaude,Judenherc,Warth,Come,Scacchi,Ristori,Pengloan,Dagaut,Cathonnet
-
p. 574 - 586
(2007/10/03)
-
- Semi-volatile and particulate emissions from the combustion of alternative diesel 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. 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
-
p. 681 - 690
(2007/10/03)
-
- Fine particle and gaseous emission rates from residential wood combustion
-
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.
-
p. 2080 - 2091
(2007/10/03)
-
- Zinc metal-promoted stereoselective olefination of aldehydes and ketones with gem-dichloro compounds in the presence of chlorotrimethylsilane
-
A combination of zinc metal and a catalytic amount of chlorotrimethylsilane has been found to promote the transformation of various aldehydes and ketones with gem-dichloro compounds, such as benzylidene dichloride (1a) and methyl dichloroacetate (1b), to the corresponding cross- coupling products, such as substituted styrene 3 and methyl acrylates 4 derivatives, under mild reaction conditions in THF. The E-isomer of the corresponding alkenes was obtained stereoselectively in good-to-excellent yields. The reaction serves as a very convenient one-pot procedure.
- Ishino, Yoshio,Mihara, Masatoshi,Nishihama, Shintaro,Nishiguchi, Ikuzou
-
p. 2669 - 2672
(2007/10/03)
-