- Preparation and properties of a novel solution of hydrogen bromide (HBr) in 1,4-dioxane: An alternative reagent to HBr gas without protic solvents
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A solution of hydrogen bromide (HBr) in 1,4-dioxane was prepared and investigated for its ability to brominate alcohols, and hydrobrominate alkenes. This study revealed that the brominating ability of this HBr/1,4-dioxane solution is equal or superior to that of hydrobromic acid or HBr in acetic acid. The solution of HBr in 1,4-dioxane is robust, exhibiting no decomposition of the solvent, and retaining 97% of its original concentration, when kept at ?25 °C for 30 days. This solution is a liquid alternative to HBr gas without protic solvents.
- Nishio, Yuya,Mifune, Ryota,Sato, Taisuke,Ishikawa, Shin-ich,Matsubara, Hiroshi
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p. 1190 - 1193
(2017/03/02)
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- Method for preparing 12-aminododecanoic acid
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The invention relates to a method for preparing 12-aminododecanoic acid and belongs to the technical field of synthesis of long carbon chain nylon monomers. The method comprises the following steps: carrying out a substitution reaction on 10-undecenoic acid and hydrogen bromide to produce 11-bromo-undecanoic acid; carrying out a hydrocyanation reaction with a cyanide reagent K[Fe(CN)6].3H2O to produce 11-cyan-undecanoic acid; and carrying out a reduction reaction, thereby obtaining the final product 12-aminododecanoic acid. The method disclosed by the invention has the advantages of being short in synthetic route, low in cost, flexible in operation, high in reaction yield, capable of obtaining the high-purity product and the like, and is very suitable for small-dose large-scale production of pharmaceutical companies or labs.
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Paragraph 0015; 0016
(2018/04/01)
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- Modular Bidentate Hybrid NHC-Thioether Ligands for the Stabilization of Palladium Nanoparticles in Various Solvents
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The synthesis of four different bidentate hybrid NHC-thioether ligands is presented. The corresponding palladium nanoparticles are stable in various solvents, depending on the ligand used, and show high chemoselectivity in the hydrogenation of olefins. The solubility of the nanoparticles can be switched multiple times depending on the pH value of the solvent. XPS analysis (which shows a subtle shift in the binding energy) was identified as a convenient tool to establish the binding mode of NHC ligands.
- Rühling, Andreas,Schaepe, Kira,Rakers, Lena,Vonh?ren, Benjamin,Tegeder, Patricia,Ravoo, Bart Jan,Glorius, Frank
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supporting information
p. 5856 - 5860
(2016/05/09)
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- A -10 preparation of cavity 11-amino undecanoic acid method
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The invention relates to a process for producing nylon 11 resin by utilizing castor oil, in particular to a method for preparing 11-aminoundecanoic acid by utilizing 10-undecenoic acid. The method comprises the following steps: proportioning 10-undecenoic acid, methylbenzene and benzene to prepare a raw material solution, and generating 11-bromoundecanoic acid by virtue of the additive reaction of the raw material solution with hydrogen bromide in a double-kettle reaction device in the presence of catalyst; ammonolyzing the 11-bromoundecanoic acid by virtue of three different processing ways without the crystallization; adding a phase-transfer catalyst in the ammonolysis reaction to accelerate the ammonolysis reaction; carrying out vacuum filtering after the ammonolysis reaction is completed, wherein a filter cake is a 11-aminoundecanoic acid crude product; adding the crude product into the deionized water, dissolving the crude product by heating the crude product, cooling and crystallizing the crude product, and filtering the crude product to obtain the refined 11-aminoundecanoic acid product.
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Paragraph 0031
(2017/02/09)
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- Selective oxoammonium salt oxidations of alcohols to aldehydes and aldehydes to carboxylic acids
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The oxidation of alcohols to aldehydes using stoichiometric 4-acetamido-2,2,6,6-tetramethylpiperidine-1-oxoammonium tetrafluoroborate (1) in CH2Cl2 at room temperature is a highly selective process favoring reaction at the carbinol center best able to accommodate a positive charge. The oxidation of aldehydes to carboxylic acids by 1 in wet acetonitrile is also selective; the rate of the process correlates with the concentration of aldehyde hydrate. A convenient and high yield method for oxidation of alcohols directly to carboxylic acids has been developed.
- Qiu, Joseph C.,Pradhan, Priya P.,Blanck, Nyle B.,Bobbitt, James M.,Bailey, William F.
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supporting information; experimental part
p. 350 - 353
(2012/03/09)
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- Multiple Electron Tunneling Paths across Self-Assembled Monolayers of Alkanethiols with Attached Ruthenium(II/III) Redox Centers
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Alkanethiol monolayers with pendant redox centers are deposited on gold electrodes by selfassembly.The monolayers are composed of both an electroactive thiol, HS(CH2)nC(O)NHCH2pyRu(NH3)5(2+/3+), with 10-15 methylene groups, and a diluent thiol, HS(CH2)mCOOH, also with 10-15 methylene groups.The monolayers are classified as "matched" (n = m), "exposed" ( n = 15, m = 10-14), and "buried" (n = 10, m = 11-15) according to the relative position of the redox center.Cyclic voltammograms in aqueous Na2SO4 indicate that the monolayers are close-packed with the redox centers residing in the aqueous phase in all but the most buried cases.Measurements of electron transfer kinetics by several methods (cyclic voltammetry, ac impedance spectroscopy, chronoamperometry) yield an internally consistent set of kinetic parameters, the standard rate constant ko, and the reorganization energy λ of the redox centers.The reorganization energies are in good agreement with the theoretically predicted value of 1.0 eV for the pyRu(NH3)5 redox centers.Plots of ln(ko) vs m are linear in all three cases.The slopes of the linear regression fit provide tunneling parameters (β, where ko ca. e-βm) of 0.97 +/- 0.03 (matched cases), 0,83 +/- 0.03 (exposed cases) and 0.16 +/- 0.02 (buried cases) per methylene.This pattern of β's is interpreted in terms of electronic coupling between the redox center and the electrode via both the redox thiol and the proximate diluent thiols, with the coupling via the diluent thiols dominating in the exposed cases.
- Finklea, Harry O.,Liu, Luna,Ravenscroft Melissa S.,Punturi, Sesto
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p. 18852 - 18858
(2007/10/03)
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- Mild Deprotection of tert-Butyl and tert-Amyl Ethers Leading either to Alcohols or to Trialkylsilyl ethers
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Tert-butyl and tert-amyl ethers afford the corresponding tert-butyldimethylsilyl ethers when treated by one equivalent of tert-butyldimethylsilyl triflate (TBDMSOTf), followed by one equivalent of 2,6-lutidine.However, treatment by a catalytic amount of TBDMSOTf without base, led to the corresponding free alcohols.
- Franck, Xavier,Figadere, Bruno,Cave, Andre
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p. 711 - 714
(2007/10/02)
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- Synthesis of Very Long Fatty Acid Methyl Esters
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Phosphoranes, produced by treating alkyltriphenylphosphonium bromides with lithium hexamethyldisilazide, reacted with ω-oxo esters to give modest yields of the corresponding methyl cis-alkenoates.By an alternative method, treatment of ω-iodo esters with the complexes formed from reactions of alkylcopper(I) and Grignard reagents gave methyl alkanoates, cis-alkenoates, and methylene-interrupted cis,cis-alka-dienoates and cis,cis,cis-trienoates.The stereochemical integrity of the esters was determined by 13C NMR spectroscopy.
- Kling, Marcel R.,Easton, Christopher J.,Poulos, Alf
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p. 1183 - 1190
(2007/10/02)
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