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Reagent

About: Reagent is a research topic. Over the lifetime, 60091 publications have been published within this topic receiving 1234928 citations. The topic is also known as: reagens.


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Patent
24 Aug 1988
TL;DR: In this article, improved specific binding assay devices comprising a chromatographic medium including a reaction site at which a specific binding reagent is immobilized, a sample application well located adjacent to the chromatogram and offset upstream from the reaction site, and a liquid absorption blotter offset downstream from the reactivity site are described.
Abstract: The present invention relates to improved specific binding assay devices comprising a chromatographic medium including a reaction site at which a specific binding reagent is immobilized, a sample application well located adjacent to the chromatographic medium and offset upstream from the reaction site, and a liquid absorption blotter offset downstream from the reaction site.

191 citations

Journal ArticleDOI
TL;DR: In this article, Grignard reagents are coupled with alkenyl halides such as 1-bromopropene and Pbromostyrene in the presence of catalytic amounts of iron(II1) complexes to afford alkenes.
Abstract: Grignard reagents are coupled with alkenyl halides such as 1-bromopropene and P-bromostyrene in the presence of catalytic amounts of iron(II1) complexes to afford alkenes. This cross-coupling reaction can be employed as a synthetic route for alkenes, in which primary, secondary as well as tertiary alkyl groups like isopropyl, cyclohexyl, and tert-butyl Grignard reagents are utilized. The reaction is stereospecific since trans-1-bromopropene affords only transbutene-2 with methylmagnesium bromide and iron(II1) pivalate. Furthermore, the rearrangement of branched alkyl groups such as tert-butyl has not been observed with an iron catalyst. Among various iron(II1) complexes examined, tris(dibenzoylm'ethido)iron(III) is the most effective from the standpoint of rates and deactivation. Product and spectral studies suggest that the active catalyst is a labile iron species derived by reduction of iron(II1) in situ by the Grignard component. High rates of cross coupling are limited by deactivation of the catalyst due to an aging process attributed to aggregation of the active iron species. Several mechanistic schemes are considered for cross coupling including (a) oxidative addition of alkenyl halide to a low valent alkyliron species followed by reductive elimination of the cross-coupled product and (b) assistance by reduced iron in the concerted displacement of halide at the alkenyl center by the Grignard reagent.

191 citations

Journal ArticleDOI
TL;DR: Mixed acidic diphenylamine-aniline sprays give specific colour reactions with uronic acids, aldoheptoses, methyl pentoses and pentoses, which is able to distinguish clearly between l -sorbose and d -fructose.

191 citations

Journal ArticleDOI
TL;DR: The fluorigenic reaction of proline with 7-fluoro-4-nitrobenzo-2-oxa-l,3-diazole (NBD-F) is superior, in terms of reactivity and fluorescence yield, to the reactions with the analogous 7-chloro and 7-bromo derivatives as mentioned in this paper.

191 citations

Journal ArticleDOI
TL;DR: In this article, aldol condensation was investigated as a catalytic route for the conversion of liquid alkanes in a biphasic system between various furfurals (furaldehyde (FUR), methyl furfural, and 5-hydroxylmethylfurfural (HMF)) and ketones (acetone, acetol, dihydroxyacetone and 2-hexanone) derived from biomass.
Abstract: Production of liquid alkanes in the range of C8–C15 from renewable sources, such as xylose and fructose (C5 and C6), requires the formation of CC bonds between the carbon chains. We have investigated aldol condensation as a catalytic route for this conversion in a biphasic system between various furfurals (furaldehyde (FUR), methyl furfural, and 5-hydroxylmethyl furfural (HMF)) and ketones (acetone, acetol, dihydroxyacetone, 2-hexanone, and 3-hexanone) derived from biomass. This system employs a reactive aqueous phase containing a basic NaOH catalyst, an organic extracting phase to remove the aldol-adducts from the homogeneous catalyst, with the addition of salt (NaCl) to the aqueous phase employed to expand the miscibility gap between the aqueous and organic phases. The effect of reagent ratios and reaction conditions on the final product distribution, such as ketone to furfural and base to furfural ratio, was investigated and a simple first order model was used to gain insight into the reaction network. High yields to single and double condensation products can be achieved for acetone condensation with furfural compounds by proper choice of reagent ratios. Degradation of HMF appears to be catalyzed by base, leading to the formation of organic acids that subsequently neutralize the base catalyst. This degradation process limits the recycling of the aqueous phase and also decreases the condensation yield of species such as hexanones that do not readily dissolve in the aqueous phase. FUR, which does not readily degrade, is more completely condensed to form products; however, because FUR is less soluble in the reactive aqueous phase compared to HMF, high concentrations of base must be used to increase the rate of reaction.

191 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20232,117
20224,093
2021785
20201,317
20191,860
20182,158