- Properties and sodium salicylate induced aggregation behavior of a tail-branched cationic surfactant with a hydroxyl-containing hydrophilic head
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A cationic surfactant with a Guerbet-type branched tail and hydroxyl-decorated head group was synthesized and characterized. Its properties including surface activity, dynamic surface tension, wetting ability, concentration/salt induced aggregation pattern transition and rheological responses of aqueous solutions were measured and analyzed. It was found that this new amphiphile possessed powerful surface activity (γcmc = 25.26 mN m-1) and could enhance the spreading of an aqueous solution on a low energy solid surface (paraffin surface); while dynamic surface tension measurements implied that the diffusion rate of surfactant molecules, influenced by the presence of hydroxyl groups, had an impact on the wetting process. It was determined that the introduction of branching hydrophobes and hydroxyls into the amphiphilic material crucially contributed to the superior performances. Moreover, a visual transition with increasing concentration of its aqueous solution was observed, while the addition of the structure-forming additive sodium salicylate (NaSal) could highly improve the viscosity by inducing the micellar growth in the cationic system which was researched by rheological experiments. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were operated to investigate the transformation of aggregates which are responsible for the concentration/salt induced phase behavior transition or rheological responses.
- Zhang, Yongjie,Li, Yunling,Song, Yongbo,Li, Jun
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p. 105952 - 105960
(2015)
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- Dehydrogenative alcohol coupling and one-pot cross metathesis/dehydrogenative coupling reactions of alcohols using Hoveyda-Grubbs catalysts
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In this study,in situformed ruthenium hydride species that were generated from Grubbs type catalysts are used as efficient catalysts for dehydrogenative alcohol coupling and sequential cross-metathesis/dehydrogenative coupling reactions. The selectivity of Grubbs first generation catalysts (G1) in dehydrogenative alcohol coupling reactions can be tuned for the ester formation in the presence of weak bases, while the selectivity can be switched to the β-alkylated alcohol formation using strong bases. The performance of Hoveyda-Grubbs 2nd generation catalyst (HG2) was improved in the presence of tricyclohexylphosphine for the selective synthesis of ester derivatives with weak and strong bases in quantitative yields. Allyl alcohol was used as self and cross-metathesis substrate for the HG2 catalyzed sequential cross-metathesis/dehydrogenative alcohol coupling reactions to obtain γ-butyrolactone and long-chain ester derivatives in quantitative yields.
- ?zer, Halenur,Arslan, Dilan,?ztürk, Bengi ?zgün
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p. 5992 - 6000
(2021/04/12)
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- Methylene-Linked Bis-NHC Half-Sandwich Ruthenium Complexes: Binding of Small Molecules and Catalysis toward Ketone Transfer Hydrogenation
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The complex [Cp*RuCl(COD)] reacts with LH2Cl2 (L = bis(3-methylimidazol-2-ylidene)) and LiBun in tetrahydrofuran at 65 °C furnishing the bis-carbene derivative [Cp*RuCl(L)] (2). This compound reacts with NaBPh4 in MeOH under dinitrogen to yield the labile dinitrogen-bridged complex [{Cp*Ru(L)}2(μ-N2)][BPh4]2 (4). The dinitrogen ligand in 4 is readily replaced by a series of donor molecules leading to the corresponding cationic complexes [Cp*Ru(X)(L)][BPh4] (X = MeCN 3, H2 6, C2H4 8a, CH2CHCOOMe 8b, CHPh 9). Attempts to recrystallize 4 from MeNO2/EtOH solutions led to the isolation of the nitrosyl derivative [Cp*Ru(NO)(L)][BPh4]2 (5), which was structurally characterized. The allenylidene complex [Cp*Ru═C═C═CPh2(L)][BPh4] (10) was also obtained, and it was prepared by reaction of 2 with HCCC(OH)Ph2 and NaBPh4 in MeOH at 60 °C. Complexes 3, 4, and 6 are efficient catalyst precursors for the transfer hydrogenation of a broad range of ketones. The dihydrogen complex 6 has proven particularly effective, reaching TOF values up to 455 h-1 at catalyst loadings of 0.1% mol, with a high functional group tolerance on the reduction of a broad scope of aryl and aliphatic ketones to yield the corresponding alcohols.
- Botubol-Ares, José Manuel,Cordón-Ouahhabi, Safa,Moutaoukil, Zakaria,Collado, Isidro G.,Jiménez-Tenorio, Manuel,Puerta, M. Carmen,Valerga, Pedro
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supporting information
p. 792 - 803
(2021/04/06)
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- ANTIFOAM AND DEFOAMER PRODUCT
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The present invention relates to a combination of specific alcohol and ester and their use as antifoam and/or defoamer. It also concerns compositions comprising it, and methods for reducing foam formation and for breaking a foam.
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Page/Page column 10
(2021/07/02)
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- Diastereoselective synthesis of functionally substituted alkene dimers and oligomers, catalysed by chiral zirconocenes
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The research addresses the reaction of terminal alkenes and propene with AlR3 (R = Me, Et) in the presence of chiral Zr complexes, rac-[Y(η5-C9H10)2]ZrCl2 (Y = C2H4, SiMe2) or (NMI)2ZrCl2 (NMI- η5–neomenthylindenyl), and methylaluminoxane. The effect of reaction conditions, catalyst and trialkylalane structure on the substrate conversion and the reaction chemo- and stereoselectivity has been studied. The reaction predominantly goes via the stage of alkene methyl(ethyl)zirconation with subsequent introduction of substrate molecules into the Zr-C bond. As a result, a diastereoselective one-pot method for the synthesis of functionally substituted linear terminal alkene dimers and propene oligomers was developed.
- Kovyazin, Pavel V.,Abdullin, Il'giz N.,Parfenova, Lyudmila V.
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p. 144 - 152
(2018/11/21)
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- Iridium catalysts for acceptorless dehydrogenation of alcohols to carboxylic acids: Scope and mechanism
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We introduce iridium-based conditions for the conversion of primary alcohols to potassium carboxylates (or carboxylic acids) in the presence of potassium hydroxide and either [Ir(2-PyCH2(C4H5N2))(COD)]OTf (1) or [Ir(2-PyCH2PBu2t)(COD)]OTf (2). The method provides both aliphatic and benzylic carboxylates in high yield and with outstanding functional group tolerance. We illustrate the application of this method to a diverse variety of primary alcohols, including those involving heterocycles and even free amines. Complex 2 reacts with alcohols to form the crystallographically characterized catalytic intermediates [IrH(η1,η3-C8H12)(2-PyCH2PtBu2)] (2a) and [Ir2H3(CO)(2-PyCH2PtBu2){μ-(C5H3N)CH2PtBu2}] (2c). The unexpected similarities in reactivities of 1 and 2 in this reaction, along with synthetic studies on several of our iridium intermediates, enable us to form a general proposal of the mechanisms of catalyst activation that govern the disparate reactivities of 1 and 2, respectively, in glycerol and formic acid dehydrogenation. Moreover, careful analysis of the organic intermediates in the oxidation sequence enable new insights into the role of Tishchenko and Cannizzaro reactions in the overall oxidation.
- Cherepakhin, Valeriy,Williams, Travis J.
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p. 3754 - 3763
(2018/05/23)
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- Methods to produce fuels
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The present disclosure generally relates to the catalytic conversion of alcohols into hydrocarbon ketones suitable for use as fuels. More specifically, the present disclosure relates to the catalytic conversion of a mixture of isopropanol-butanol-ethanol (IBE) or acetone-butanol-ethanol (ABE), into ketones suitable for use as fuels. The ABE or IBE mixtures may be obtained from the fermentation of biomass or sugars.
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Page/Page column 50; 51
(2018/02/28)
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- GUERBET CONDENSATION REACTION
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The invention relates to a process for the preparation of a Guerbet alcohol, comprising the steps of: (a) providing at least one alcohol, wherein said at least one alcohol has a carbon atom bearing at least one hydrogen atom adjacent to the hydroxyl group; (b) providing a catalyst composition, wherein said catalyst composition comprises an alkaline catalyst and a copper-nickel catalyst comprised in a hydrotalcite; (c) mixing alcohol (a) with catalyst composition (b), thereby obtaining a mixture; and, (d) heating said mixture; thereby obtaining a Guerbet alcohol.
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Page/Page column 17-18; 28
(2017/07/08)
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- Ni?Cu Hydrotalcite-Derived Mixed Oxides as Highly Selective and Stable Catalysts for the Synthesis of β-Branched Bioalcohols by the Guerbet Reaction
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A series of Ni?Cu hydrotalcite-derived mixed oxides have been synthesized and evaluated as heterogeneous catalysts for the dimerization of linear aliphatic alcohols to afford β-branched Guerbet alcohols. The use of the hydrotalcite-structured catalyst precursor highly favors the catalyst stability. This Cu/Ni catalyst has an enhanced reducibility of Ni2+ species under reaction conditions, favoring the hydrogen transfer and hydrogenation capacity of the catalyst system. Catalytic results are reported for C8, mixed C8/C10, and C18 alcohol feeds, with full conversions and Guerbet product purities of 72.5–96 %.
- Hernández, Willinton Y.,De Vlieger, Kevin,Van Der Voort, Pascal,Verberckmoes, An
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p. 3196 - 3205
(2016/11/29)
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- Synthetic base stock based on Guerbet alcohols
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Guerbet (β branched) alcohols of varying chain length of even carbon numbers were synthesized by using single linear fatty alcohols ranging from 1-octanol to 1-dodecanol. All Guerbet alcohols having fewer than 28 carbon atoms and are liquid at 0 °C due to β branching. Synthetic base oils were prepared by reacting commonly available unsaturated fatty acids and dicarboxylic acids with Guerbet alcohols using p-toluenesulfonic acid as a catalyst. These base oils were characterized by physical and tribological properties like viscosity, viscosity index, pour point, flash point, wear scar, weld load, coefficient of friction etc. and compared with commercially available 150 and 500 N base oils.
- Waykole, Chetan,Bhowmick, Diptinarayan,Pratap, Amit
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p. 1407 - 1416
(2014/08/18)
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- Lubricant Composition for Fluid Dynamic Bearing
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A lubricating oil composition for fluid dynamic bearings which comprises 50 to 100% by mass of an ether compound comprising at least one ether bond and having 11 to 34 carbon atoms as the base oil and has a kinematic viscosity of at least 2.2 mm2/s at 100° C. is provided. The composition has excellent viscosity characteristics such as excellent fluidity at low temperatures and a small decrease in the viscosity in a high temperature range, exhibits lower evaporability, excellent energy saving property and excellent heat stability and is advantageously used for compact fluid dynamic bearings used under rotation at a high speed.
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- Guerbet reaction of primary alcohols leading to β-alkylated dimer alcohols catalyzed by iridium complexes
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[IrCl(cod)]2 and [Cp*IrCl2]2 complexes catalyzed efficiently the Guerbet reaction of primary alcohols to β-alkylated dimer alcohols in good yields. For instance, the reaction of 1-butanol in the presence of [Cp*IrCl2]2 (1 mol %), t-BuOK (40 mol %), and 1,7-octadiene (10 mol %) produced 2-ethyl-1-hexanol in 93% yield. Various primary alcohols undergo the Guerbet reaction under the influence of Ir complexes to give the corresponding dimer alcohols in good yields. This method provides an alternative direct route to β-alkylated primary alcohols which are prepared by aldol condensation of aldehydes followed by hydrogenation.
- Matsu-Ura, Toyomi,Sakaguchi, Satoshi,Obora, Yasushi,Ishii, Yasutaka
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p. 8306 - 8308
(2007/10/03)
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- Method for producing branched alcohols and/or hydrocarbons
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Processes for producing branched compounds are described wherein a carbonyl compound is condensed in the presence of a catalyst selected from the group consisting of acids and bases, to form an α,β-unsaturated condensation product; and the α,β-unsaturated condensation product is hydrogenated.
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- 1,3,5-triazine-2,4,6-tris-alkylaminocarboxylic acid amino esters, biocidal agents containing such esters, and methods of preparing them
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1,3,5-Triazine-2,4,6-tris-alkylaminocarboxylic acid amino esters of the general formula (I): 1,3,5-triazine-2,4,6-tris[NH--(CH2)n --CO--O--R1 ], in which R1 denotes the radical of an alkanolamine, can be employed as biocidal or biostatic compounds in aqueous systems, in particular in cooling lubricants.
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- Model compounds for biodegradation studies on hydrocarbon-type dielectric fluids
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The hydrocarbons 7-methylpentadecane (1, n = 0) and 7-methyl-9-n-hexyl heptadecane (1, n = 1) have been synthesized.These compounds are suitable as model compounds for biodegradation studies on mixtures of oligomers of 1-octene and related compounds which have been proposed as dielectric fluids for the replacement of PCB's.The synthesis confirms the feasibility of isotope labelling for such biodegradation studies.
- Baarschers, Willem Hendrik,Li, Maria Angela
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p. 1784 - 1787
(2007/10/02)
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