- Separation of enantiomers by extraction based on lipase-catalyzed enantiomer-selective fluorous-phase labeling
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No chromatography is necessary to separate a racemic alcohol into its enantiomers. A highly fluorinated acyl residue was tranferred in an enantiomer-selective manner onto a racemic alcohol in the presence of a lipase [Eq. (1)]. The labeled enantiomer was separated from the unlabeled one by a simple but very efficient partition between fluorous and organic phases.
- Hungerhoff, Benno,Sonnenschein, Helmut,Theil, Fritz
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- Preparation method of supercritical carbon dioxide thickening agent for exploring tight oil and gas reservoir
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The invention relates to a preparation method of a supercritical carbon dioxide thickening agent for exploring a tight oil and gas reservoir. The problem that oil and gas reservoirs are damaged by adopting conventional mining methods is solved. According
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Paragraph 0017; 0018; 0022; 0023; 0027; 0028
(2019/11/13)
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- Method for preparing supercritical carbon dioxide thickener for exploitation of extra-low permeability ultra-low permeability oil and gas reservoir
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The invention relates to a method for preparing a supercritical carbon dioxide thickener for exploitation of an extra-low permeability ultra-low permeability oil and gas reservoir, and aims to solve the problem that an oil and gas reservoir is damaged by a common exploitation mode. According to the technical scheme, the method comprises the following steps: putting a bottle into an ice water bath,adding perfluorooctyl ethanol, toluenesulfonyl chloride and pyridine, performing a reaction for three hours at 0-20 DEG C, adding filtering paper after the reaction is completed, performing ultrasonic dispersion for one hour, removing the filtering paper, and washing for 3-5 times with diluted hydrochloric acid so as to obtain an intermediate (1); putting (N-tert-butyloxy carbonyl) trihydroxymethyl aminomethane and the intermediate (1) into another bottle, adding potassium carbonate and N-N-dimethyl formamide, and heating to 60 DEG C to implement a reaction for four hours so as to obtain an intermediate (2); and finally adding trifluoroacetic acid, dichloromethane and the intermediate (2), performing a reaction for two hours at 50 DEG C, performing extraction and vacuum drying, adding 1,6-caproyl diisocyanate, and performing a reaction for two hours at 55 DEG C, thereby obtaining a final product. By adopting the thickener, the viscosity of carbon dioxide can be increased, and the thickener can be applied to fracturing transformation and chemical flooding.
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Paragraph 0017; 0018; 0022; 0023; 0027; 0028
(2019/11/04)
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- Sustainable Micellar Gold Catalysis - Poly(2-oxazolines) as Versatile Amphiphiles
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The application of five polymer amphiphiles in the gold-catalyzed allene cycloisomerizations under aqueous micellar conditions is described. The polymers were prepared by ring-opening cationic polymerization based on poly(2-methyl-2-oxazoline) as hydrophilic segment and different hydrocarbon- or fluorocarbon-based hydrophobic segments. The catalytic activity in the gold-catalyzed allene cyclization is strongly dependent on the type of gold precursor, the salt concentration in the bulk aqueous medium, and the concentration of the polymeric amphiphile. Best results were obtained with 2 mol% of gold(III) bromide, 1 mM of amphiphile and 5 M sodium chloride, affording over 80% yield for different heterocyclic products. The catalyst system is also suitable for the dehydrative cyclization of acetylenic diols to furans. Moreover, successful catalyst recycling was demonstrated in three consecutive runs when using optimized extraction conditions.
- Lempke, Linda,Ernst, Andrea,Kahl, Fabian,Weberskirch, Ralf,Krause, Norbert
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supporting information
p. 1491 - 1499
(2016/05/19)
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- Combining lipase-catalyzed enantiomer-selective acylation with fluorous phase labeling: A new method for the resolution of racemic alcohols
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Lipase-catalyzed acylation of racemic alcohols with a highly fluorinated acyl donor allows their kinetic resolution accompanied by the simultaneous enantiomer-selective fluorous phase labeling. Both the tagged and the untagged enantiomer can be separated without chromatography by a very efficient partition between a fluorous and an organic phase. The method has been successfully applied to the resolution of typically racemic secondary alcohols of low molecular weight. The fluorous label can be recovered quantitatively.
- Hungerhoff, Benno,Sonnenschein, Helmut,Theil, Fritz
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p. 1781 - 1785
(2007/10/03)
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- Macrocyclic ligands with partially fluorinated sidearms: Synthesis and metal ion complexation
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Derivatives of aza-12-crown-4, aza-15-crown-5, aza-18-crown-6, 1,10- diaza-18-crown-6 and 1,4,8,12-tetraazacyclopentadecane with partially fluorinated substituents attached to nitrogen are prepared. Their efficiencies and selectivities in alkali metal and
- Elshani, Sadik,Kobzar, Evgeny,Bartsch, Richard A.
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p. 3291 - 3301
(2007/10/03)
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