Aqueous high-temperature chemistry of carbo- and heterocycles. 1. Introduction and reaction of 3-pyridylmethanol, pyridine-3-carboxaldehyde, and pyridine-3-carboxylic acid

Katritzky, Alan R.; Łapucha, Andrzej R.; Murugan, Ramiah; Luxem, Franz J.; Siskin, Michael; Brons, Glen

doi:10.1021/ef00023a015

Cited by 37 publications

(43 citation statements)

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“…By contrast, most of the work of the Katritzky and Siskin groups was carried out with small sealed metal tubes held in a fluidized sand bath for up to several days at a time. , When alternative conditions were investigated for a given reaction, usually temperatures differing by between 50 and 100 °C, and times differing by days, were selected . Although that methodology was suitable for the degradative reactions studied, it would not have been ideal for preparative studies owing to the constraints of scale, lack of stirring and sampling during reactions, large increments in temperature, and the lengthy times employed.…”

Section: Resultsmentioning

confidence: 99%

“…Synthetic procedures developed by several groups have employed temperatures at and below boiling . On the other hand, conditions near supercritical ( T c water = 374 °C) have been investigated mainly for production of liquid and gaseous fuels from biomass, for geochemical modeling, − and for the destruction of waste and hazardous organic materials. − Jointly, the groups of Katritzky and Siskin conducted extensive studies 4-25 and found that superheated water not only was an effective solvent for organic reactions but also could react.…”

Section: Introductionmentioning

confidence: 99%

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Applications of High-Temperature Aqueous Media for Synthetic Organic Reactions

et al. 1997

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Preparative organic synthesis was investigated in aqueous media at temperatures up to 300 degrees C. Experiments were conducted with a recently disclosed pressurized microwave batch reactor (MBR) or in conventionally heated autoclaves. Thirty-six examples are presented. Among these, methods were developed for a Fischer synthesis, an intramolecular aldol condensation that was scaled up, decarboxylation of indole-2-carboxylic acid, Rupe rearrangement of 1-ethynyl-1-cyclohexanol, isomerization of carvone to carvacrol, and conversion of phenylacetylene to acetophenone. The applicability of high-temperature water was also demonstrated for biomimetic processes important in food, flavor, and aroma chemistry and for tandem reactions such as formation of 2-methyl-2,3-dihydrobenzofuran from allyl phenyl ether. When addition of acid or base was necessary, less agent was usually required for high-temperature processes than for those at and below boiling, and the reactions often proceeded more selectively. In some instances the requirement was orders of magnitude lower, with obvious consequences for safe, economic processing and for lowering costs of effluent disposal. The diversity of reactions indicates that high-temperature aqueous media could play an increasingly important role in the development of new preparative processes.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Applications of High-Temperature Aqueous Media for Synthetic Organic Reactions

et al. 1997

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“…In their experiments, the pressure in the reactor was not measured but from the amount of water they reported using, their pressure was higher than in our conditions. 1.0 g of octyl sulfide and 7.0 mL of water or cyclohexane was reportedly loaded in a 12.5 mL reactor in their experiments 50 while we loaded our 24 mL reactor with 2.0 g of octyl sulfide and 3.5 g of water or 3.0 g of cyclohexane. We were constrained to lower pressure (275 bar) in our reactor due to safety considerations.…”

Section: Hexyl Sulfide Decomposition With and Without Scwmentioning

confidence: 97%

Combining experiment and theory to elucidate the role of supercritical water in sulfide decomposition

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et al. 2014

Phys. Chem. Chem. Phys.

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The cleavage of C-S linkages plays a key role in fuel processing and organic geochemistry. Water is known to affect these processes, and several hypotheses have been proposed, but the mechanism has been elusive. Here we use both experiment and theory to demonstrate that supercritical water reacts with intermediates formed during alkyl sulfide decomposition. During hexyl sulfide decomposition in supercritical water, pentane and CO + CO2 were detected in addition to the expected six carbon products. A multi-step reaction sequence for hexyl sulfide reacting with supercritical water is proposed which explains the surprising products, and quantum chemical calculations provide quantitative rates that support the proposed mechanism. The key sequence is cleavage of one C-S bond to form a thioaldehyde via radical reactions, followed by a pericyclic addition of water to the C[double bond, length as m-dash]S bond to form a geminal mercaptoalcohol. The mercaptoalcohol decomposes into an aldehyde and H2S either directly or via a water-catalyzed 6-membered ring transition state. The aldehyde quickly decomposes into CO plus pentane by radical reactions. The time is ripe for quantitative modelling of organosulfur reaction kinetics based on modern quantum chemistry.

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“…The dissociation constant of water increases with temperature, reaching a maximum at around 250–275 °C, which makes this an interesting temperature range for subcritical water chemistry. In a series of papers, − the conversion of pyridine and its derivatives was investigated by keeping the pyridines and water at reaction conditions of 250 °C and high pressure for several days. Although some conversions were observed, the nitrogen group was not eliminated from the pyridines.…”

Section: Chemical Conversion Followed By Separationmentioning

confidence: 99%

Nitrogen Removal from Oil: A Review

2016

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The selective removal of nitrogen-containing compounds from oil and oil fractions is of interest because of the potential deleterious impact of such compounds on products and processes. Problems caused by nitrogen-containing compounds include gum formation, acid catalyst inhibition and deactivation, acid−base pair-related corrosion, and metal complexation. A brief overview of the classes of nitrogen compounds found in oil is provided. The review of processes to remove nitrogen from oil emphasizes studies that investigated denitrogenation of industrial feedstocks, such as refinery fractions, heavy oils, and bitumens. The main topics covered are hydrotreating, liquid−liquid phase partitioning, solvent deasphalting, adsorption, chemical conversion followed by separation, and microbial conversion. Chemical conversion processes include oxidative denitrogenation, N-alkylation, complexation with metal salts, and conversion in high-temperature water. There are many processes for denitrogenation by separation of the nitrogen-rich products from oil without removing the nitrogen group from the nitrogencontaining compounds. As a consequence, most of these processes are viable mainly for removal of nitrogen from low-nitrogencontent oils, typically with <0.1 wt % N. At present, hydrodenitrogenation appears to be the only industrially viable process for nitrogen removal from oils with high nitrogen content.

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Aqueous high-temperature chemistry of carbo- and heterocycles. 1. Introduction and reaction of 3-pyridylmethanol, pyridine-3-carboxaldehyde, and pyridine-3-carboxylic acid

Cited by 37 publications

References 0 publications

Applications of High-Temperature Aqueous Media for Synthetic Organic Reactions

Applications of High-Temperature Aqueous Media for Synthetic Organic Reactions

Combining experiment and theory to elucidate the role of supercritical water in sulfide decomposition

Nitrogen Removal from Oil: A Review

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