Готові списки джерел за темами / Aromatic condensation

Добірка наукової літератури з теми "Aromatic condensation"

Автор: Grafiati

Опубліковано: 10 грудня 2022

Оновлено: 28 січня 2023

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Статті в журналах з теми "Aromatic condensation"

Witzig, Reto M., and Christof Sparr. "Synthesis of Enantioenriched Tetra-ortho-3,3′-substituted Biaryls by Small-Molecule-Catalyzed Noncanonical Polyketide Cyclizations." Synlett 31, no. 01 (October 22, 2019): 13–20. http://dx.doi.org/10.1055/s-0039-1690215.

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The arene-forming aldol condensation is a fundamental reaction in the biosynthesis of aromatic polyketides. Precisely controlled by the polyketide synthases, the highly reactive poly-β-carbonyl substrates are diverged into numerous aromatic natural products by selective cyclization reactions; a fascinating biosynthetic strategy that sparked our interest to investigate atroposelective aldol condensations. In this Account, we contextualize and highlight the ability of small-molecule catalysts to selectively convert noncanonical hexacarbonyl substrates in a double arene-forming aldol condensation resulting in the atroposelective synthesis of tetra-ortho-3,3′-substituted biaryls. The hexacarbonyl substrates were obtained by a fourfold ozonolysis enabling a late-stage introduction of all carbonyl functions in one step. Secondary amine catalysts capable of forming an extended hydrogen-bonding network triggered the noncanonical polyketide cyclization in order to form valuable biaryls in high yields and with stereocontrol of up to 98:2 er.1 Biosynthesis of Aromatic Polyketides2 Rotationally Restricted Aromatic Polyketides3 3,3′-Substituted Binaphthalenes in Catalysis4 Stereoselective Synthesis of Atropisomers5 Synthesis of Enantioenriched Tetra-ortho-3,3′-Substituted Biaryls by the Atroposelective Arene-Forming Aldol Condensation6 Conclusion

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Moth‐Poulsen, Kasper, Theis Reenberg, Thomas Bjørnholm, and Jørn B. Christensen. "Microwave Assisted Condensation of Aromatic Methyl Groups with Aromatic Aldehydes." Synthetic Communications 34, no. 12 (December 31, 2004): 2215–21. http://dx.doi.org/10.1081/scc-120038503.

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Miller, J. Houston. "Aromatic excimers: evidence for polynuclear aromatic hydrocarbon condensation in flames." Proceedings of the Combustion Institute 30, no. 1 (January 2005): 1381–88. http://dx.doi.org/10.1016/j.proci.2004.08.192.

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Kundu, Kshama, and Sandip Nayak. "Camphor-10-sulfonic acid catalyzed condensation of 2-naphthol with aromatic/aliphatic aldehydes to 14-aryl/alkyl-14H-dibenzo[a,j]xanthenes." Journal of the Serbian Chemical Society 79, no. 9 (2014): 1051–58. http://dx.doi.org/10.2298/jsc130805021k.

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(?)-Camphor-10-sulfonic acid (CSA) catalyzed condensation of 2-naphthol with both aliphatic/aromatic aldehydes at 80?C yielded 14-alkyl/aryl-dibenzoxanthenes as the sole product in high yields. However, the same condensation with benzaldehyde at 25?C afforded a mixture of intermediate 1,1-bis-(2-hydroxynaphthyl)phenylmethane and 14-phenyl-dibenzoxanthene while the condensation with aliphatic aldehydes at 25?C furnished the corresponding 14-alkyl-dibenzoxanthenes as the sole product. Moreover, condensation of 2-naphthol with aromatic/aliphatic aldehydes with low catalyst loading (2 mol%) was greatly accelerated under microwave irradiation to afford the corresponding 14-aryl/alkyl-dibenzoxanthenes as the sole product in high yields.

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He, Yan-Hong, Gang-Qiang Wang, Ke-Ling Xu, and Zhi Guan. "An Efficient Procedure for the Synthesis of Polysubstituted Pyrroles in an Ionic Liquid." Zeitschrift für Naturforschung B 66, no. 2 (February 1, 2011): 191–96. http://dx.doi.org/10.1515/znb-2011-0212.

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The ionic liquid 1-butyl-3-methyl-imidazolium hydrogen sulfate, [bmim]HSO4, was used as a catalyst and reaction medium for the pyrrole synthesis, and a wide range of aliphatic, aromatic, heteroaromatic and carboxylic 1,4-diketones easily underwent condensations with aniline and ethylenediamine to form polysubstituted pyrroles. Sequential decarboxylation/Paal-Knorr pyrrole condensation was observed, which provides a new and facile approach to monoester pyrroles from 1,4-diketo-2,3-dicarboxylic acid esters.

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Pelageev, D. N., and V. Ph Anufriev. "Condensation of hydroxy naphthazarins with aromatic aldehydes." Russian Chemical Bulletin 57, no. 11 (November 2008): 2335–39. http://dx.doi.org/10.1007/s11172-008-0332-0.

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Paromov, Artyom E., Sergey V. Sysolyatin, and Irina A. Shchurova. "Condensation of 4-Tert-butyl-2,6-dimethylbenzenesulfonamide with Glyoxal and Reaction Features: A New Process for Symmetric and Asymmetric Aromatic Sulfones." Molecules 27, no. 22 (November 12, 2022): 7793. http://dx.doi.org/10.3390/molecules27227793.

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The synthesis of substituted aza- and oxaazaisowurtzitanes via direct condensation is challenging. The selection of starting ammonia derivatives is very limited. The important step in developing alternative synthetic routes to these compounds is a detailed study on their formation process. Here, we explored an acid-catalyzed condensation between 4-tert-butyl-2,6-dimethylbenzenesulfonamide and glyoxal in aqueous H2SO4, aqueous acetonitrile and acetone, and established some new processes hindering the condensation. In particular, an irreversible rearrangement of the condensation intermediate was found to proceed and be accompanied by the 1,2-hydride shift and by the formation of symmetric disulfanes and sulfanes. It has been shown for the first time that aldehydes may act as a reducing agent when disulfanes are generated from aromatic sulfonamides, as is experimentally proved. The condensation between 4-tert-butyl-2,6-dimethylbenzenesulfonamide and formaldehyde resulted in 1,3,5-tris((4-(tert-butyl)-2,6-dimethylphenyl)sulfonyl)-1,3,5-triazinane. It was examined if diimine could be synthesized from 4-tert-butyl-2,6-dimethylbenzenesulfonamide and glyoxal by the most common synthetic procedures for structurally similar imines. It has been discovered for the first time that the Friedel–Crafts reaction takes place between sulfonamide and the aromatic compound. A new synthetic strategy has been suggested herein that can reduce the stages in the synthesis of in-demand organic compounds of symmetric and asymmetric aromatic sulfones via the Brønsted acid-catalyzed Friedel–Crafts reaction, starting from aromatic sulfonamides and arenes activated towards an electrophilic attack.

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Fairhurst, Magnus, Muhammad Zeeshan, Bengt Haug, and Annette Bayer. "Aldol Condensations on a 3-Alkylidene-2,5-diketopiperazine: Synthesis of Two Marine Natural Products." Synlett 29, no. 10 (January 30, 2018): 1303–6. http://dx.doi.org/10.1055/s-0036-1591755.

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The synthesis of two marine natural products containing a 3-alkylidene-6-arylidene-2,5-diketopiperazine scaffold by employing two consecutive aldol condensations starting with 1,4-diacetyl-2,5-diketopiperazine is reported. The target compounds contain a phenol or an imidazole group as aryl substituents, respectively, and suitable conditions for the aldol condensation of 1-acyl-3-alkylidene-2,5-diketopiperazine with the required functionalised aromatic aldehydes were developed. Provided the optimal base was used, introduction of the phenol group did not require use of a protecting group. Boc-protection was beneficial for introduction of the imidazole group, and conditions for carrying out the aldol condensation and Boc-deprotection in one step were identified. The stereochemistry of the target compounds was confirmed by NMR analysis.

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Badiger, Krishnappa B., and Kantharaju Kamanna. "Knoevenagel condensation reaction catalysed by agro-waste extract as a greener solvent catalyst." Organic Communications 14, no. 1 (March 26, 2021): 81–91. http://dx.doi.org/10.25135/acg.oc.99.21.01.1948.

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This paper present a novel Knoevenagel reaction protocol for the condensation of aromatic/heteroaromatic aldehydes with malononitrile to give α, β–unsaturated benzylidene derivatives. The main focus of this work is to reveal the usability of agro-waste extracts as a catalyst in the Knoevenagel condensation. The present protocol proceeds efficiently for various substituted aromatic and heterocyclic aldehydes in the Knoevenagel reactions. In addition, the present method describes direct isolation of the formed products without using organic solvent extraction gave good yields product.

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Chang, Guan Jun, Lin Zhang, and Run Xiong Lin. "Synthesis of Poly(Aryl Sulfone Benzimidazole) Sulfone." Advanced Materials Research 284-286 (July 2011): 1867–70. http://dx.doi.org/10.4028/www.scientific.net/amr.284-286.1867.

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Sulfoned aromatic acid and o-phenylenediamine as the monomers, sulfoned-benzimidazole was obtained by condensation reaction. Poly(aryl sulfone benzimidazole) sulfone (PSBIS) as novel heat-resistant polymer was obtained by the condensation polymerization via Palladium-catalyzed aryl amination reaction of sulfoned-benzimidazole and aromatic dibromide. Differential scanning calorimetry (DSC) and thermal analysis (TG) measurements showed that the polymer synthesized possessed high glass transition temperature (Tg>321°C), good thermal stability with high decomposition temperature (TD>540°C) and good solubility.

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Більше джерел

Дисертації з теми "Aromatic condensation"

Sadeghipour, Mitra Jr. "Hydrocarbon Functionalization via a New Free Radical-Based Condensation Reaction." Diss., Virginia Tech, 1998. http://hdl.handle.net/10919/30627.

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A new free radical chain process for the allylation of hydrocarbons and some other substrates utilizing substituted allyl bromides (R-H + C=C-C-Br -> R-C-C=C + HBr) has been developed. Good to excellent yields were observed in all cases. Kinetic chain measurements and competition experiments were performed in order to elucidate the mechanism of the reaction. Overall, the results are consistent with a free radical chain process with bromine atom as the chain carrier. Substitution effects on the reactivity of the allyl bromides (CH2=C(Z)CH2Br) and their influence on the overall reaction rate were studied by conducting several competition experiments. The relative rate constants for addition of benzyl radical to CH2=C(Z)CH2Br are: Z=CN(180), COOEt(110), Ph(65), H(1.0). The trend of electronegativity/reactivity of these reactions was very similar to that reported for addition of benzyl radical to substituted alkenes. Other than alkyl aromatics (PhCH3, PhCH(CH3)2), other substrates (i.e., 2- propanol, phenyl cyclopropane) were also tested for this allylation reaction. The magnitude and scope of these reactions, and their synthetic utility is discussed.
Ph. D.

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Bouxin, Florent. "Solvolyse des lignines : production de synthons aromatiques de faibles masses." Thesis, Reims, 2011. http://www.theses.fr/2011REIMS004/document.

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Les lignines ne sont pas suffisamment considérées dans les procédés de bioraffinerie. Pourtant, elles sont une source abondante de synthons aromatiques, et éléments essentiels de la rentabilité de transformation des lignocelluloses. A ce jour, les perspectives de production de synthons à partir des lignines se heurtent aux réactions de condensations des lignines, limitant leurs conversions en produits de faibles masses. Cette étude nous a permis de cerner les conditions propices à l’hydrolyse et/ou aux condensations grâce à l’étude de différentes lignines modèles soumises aux conditions d’acidolyse. D’une part, les conditions propices à l’hydrolyse des liaisons -O-4 sont l’utilisation d’une catalyse homogène (HCl), pour des températures comprises entre 120 et 140°C et une acidité de l’ordre de 0.05 M. A l’inverse, l’emploi d’une catalyse hétérogène (Montmorillonite K10) est peu efficace car elle doit s’affranchir des phénomènes d’adsorption du substrat tout en lui permettant d’accéder à ses sites actifs. D’autre part, les réactions de condensation secondaires sont exacerbées par l’emploi de l’argile de Montmorillonite, mais aussi par l’augmentation de l’acidité et de la température, elles mêmes nécessaires pour une bonne hydrolyse. La substitution de l’alcool coniférylique par le coniféraldéhyde permet de minimiser ces condensations secondaires du fait de sa forte stabilité dans les conditions d’acidolyse. Toutefois, l’incorporation de ce type de précurseur dans les lignines provoque une diminution de la fréquence des liaisons -O-4. Cette réduction du potentiel d’hydrolyse des lignines est compensée par l’exacerbation des réactions de rétroaldolisation. Pour les condensations primaires, l’acidolyse des lignines pures -O-4 nous permet d’affirmer que celles-ci, constantes face à l’augmentation de la concentration en acide et en nucléophiles aromatiques, seraient plutôt de type intramoléculaire
Lignins are not sufficiently considered in the biorefinery processes. However, they are a rich source of aromatic building blocks, and essential elements of lignocellulose processing viability. Although the production prospects of building blocks from lignins exist, their strong affinities for condensation reactions limit the conversion into low molecular weight products. This study allowed us to identify hydrolysis or condensation suitable conditions by studying different models lignins subjected to acidolysis conditions. On the one hand, suitable conditions for the -O-4 bonds hydrolysis are the use of homogeneous catalysis (HCl), for temperatures and HCl concentration ranged from 120 to 140 ° C and from 0.05 M to 0.1M. In contrast, the use of heterogeneous catalysis (Montmorillonite K10) is inefficient because it has to overcome the substrate adsorption and allow an access to its active sites. On the other hand, secondary condensation reactions are exacerbated by the use of Montmorillonite clay, but also by acidity and temperature increases, themselves necessary for an efficient hydrolysis.The substitution of coniferyl alcohol by coniferaldehyde minimizes these condensation reactions due to its high stability in acid conditions. However, the incorporation of this precursor in lignin leads to a decrease of -O-4 bond frequency. This reduction of lignin hydrolysis potential is compensated for the exacerbation of retroaldolisation reactions. About primary condensations, pure -O-4 lignins acidolysis allows us to claim that this kind of reactions, unchanged at the hand of acid or aromatic nuclei concentration increase, are intramolecular

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Silver, David J. "Occupational exposure to ultrafine particles and polycyclic aromatic hydrocarbons from candle emissions." [Tampa, Fla] : University of South Florida, 2005. http://purl.fcla.edu/usf/dc/et/SFE0001426.

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Li, Qiang. "Surface Chemistry of Hexacyclic Aromatic Hydrocarbons on (2x1) and Modified Surfaces of Si(100)." Thesis, University of Waterloo, 2004. http://hdl.handle.net/10012/1263.

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Room-temperature chemisorption of hexacyclic aromatic hydrocarbons on the 2x1, sputtered, oxidized and H-terminated Si(100) surfaces, as well as those upon post treatments of hydrogenation, oxidization and electron irradiation have been investigated by using thermal desorption spectrometry (TDS), Auger electron spectroscopy (AES) and low energy electron diffraction (LEED). This work focuses on the effects of the functional groups (phenyl, methyl, vinyl, heteroatom, and H atom) in the chemisorbed aromatic hydrocarbons (benzene, toluene, xylene isomers, styrene and pyridine) on organic functionalization of the Si(100) surface, particularly on such surface processes as cycloaddition, dative adsorption, hydrogen abstraction, desorption, dissociation, diffusion, and condensation polymerization. Unlike the earlier notion that hydrogen evolution in the hydrocarbon/Si(100) systems is the result of hydrocarbon dissociation (into smaller hydrocarbon fragments and H atoms) on the surface, condensation polymerization of the adsorbed aromatic hydrocarbons is proposed in the present work, in order to explain the higher-temperature hydrogen evolution feature in the toluene/Si(100) system. This hypothesis is supported by our TDS results for other hydrocarbon adsorbates, especially in the pyridine/Si(100) system where electron-induced condensation polymerization has been observed at room temperature. The improved techniques in the TDS experiments developed in the present work have enabled us to observe condensation polymerization and the effect of H on the surface processes (via surface reconstruction) on Si(100) for the first time. New analysis methods have also been developed to determine the adsorption coverage from the AES data, and this work has not only improved the accuracy of the elemental-coverage evaluation, but also provided a means to estimate the rate and the order of chemisorption. By using the density functional theory with the Gaussian 98 program, the adsorption geometries and the corresponding adsorption energies of various adsorption phases have been calculated. These computational results have provided useful insights into the chemisorption structures on the Si(100) surface. The present work also presents the development of three kinetics models for hydrogen evolution in the aforementioned aromatic-hydrocarbon systems on Si(100). Based on a modified collision theory with consideration of diffusion, these theoretical models have proven to be quite successful in simulating the observed TDS profiles and in estimating the kinetic parameters for the analysis of condensation polymerization in 2-dimensional diffusion systems. The present work illustrates that TDS experiments can be used effectively with quantum computation and theoretical kinetics modelling to elucidate the intricate nature of organosilicon surface chemistry.

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Tunc, Deniz. "Synthesis of functionalized polyamide 6 by anionic ring-opening polymerization." Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0178/document.

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Les études présentées dans le cadre de cette thèse visent à copolymériser l'ԑ-caprolactame (CL) avec différents dérivés de l'α-amino-ԑ-caprolactame (qui possèdent une amine primaire fonctionnalisable) par polymérisation anionique par ouverture de cycle. En utilisant cette stratégie, nous décrivons; (i) la préparation de polyamides 6 fluorés thermiquement plus stables, et ayant une surface hydrophobe; (ii) la synthèse de polyamides 6 portant des groupes pendants cinnamoyl thermo et photosensibles. Une réticulation réversible est observée ainsi que l'amélioration des propriétés thermo-mécaniques; (iii) la copolymérisation anionique par ouverture de cycle de CL avec un bis-monomère issu de l'α-amino-ԑ-caprolactame comme contrôle de la réticulation du polyamide 6. Enfin, dans le cadre de notre intérêt continu pour la chimie du polyamide 6, nous avons mis en évidence la possible combinaison de la polymérisation anionique par ouverture de cycle de CL avec la polycondensation en chaîne de l'éthyl-4-butylaminobenzoate pour obtenir en une étape un polyamide aliphatique/aromatique
The studies presented in this thesis aim to copolymerize ԑ-caprolactam (CL) with different derivatives of α-amino-ԑ-caprolactam (which has a functionalizable primary amine) via anionic ring-opening polymerization. By using this strategy, we describe: (i) the synthesis of thermally more stable fluorinated polyamide 6 having a hydrophobic surface; (ii) the synthesis of polyamides 6 bearing pendant cinnamoyl groups, which are thermo-and photoresponsivechromophore groups, and demonstrating their reversible crosslinking as well as improved thermo-mechanical properties; (iii) the copolymerization ofCL with a crosslinker (N-functionalized α-amino-ԑ-caprolactambis-monomers) into crosslinked polyamides 6.As part of our continuing interest in polyamide 6 chemistry, we developed the combination of anionic ring-opening polymerization of CL and chain-growth condensation polymerization of ethyl 4-butylaminobenzoate in order to obtain aliphatic/aromatic polyamides in one-step

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McBeath, Anna Vera. "Aromatic condensation of black carbon : its measurement and importance." Thesis, 2012. http://hdl.handle.net/2440/84512.

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Black carbon (BC) is an important constituent of soils and sediments due to its role in a range of biogeochemical processes. However, since BC represents a continuum of materials with no clear-cut boundaries, it is challenging to identify and quantify. This limits our understanding of its contribution to terrestrial, marine and atmospheric carbon cycles and the role it plays in influencing climate. The focus of this study was on first improving and refining a novel solid-state ¹³C nuclear magnetic resonance (NMR) spectroscopic that offers great potential for the characterisation of BC. Once optimised, this technique was applied to a variety of BC samples in order to address some key questions in BC science. The technique developed here is a simple and rapid method for gauging the degree of aromatic condensation of chars, a molecular-scale property that affects both their degradability and sorption affinity. The foundation for the technique has been described previously. Its basis is the effect that “ring currents” that are induced in aromatic structures have on the ¹³C NMR chemical shift of probe molecules when sorbed to the char. The improvement in the technique described here involves a direct addition of the probe molecule (¹³C₆-benzene) directly to the dry char. This is demonstrated to be a much more efficient method of loading the probe molecule, both in terms of the amount of expensive ¹³C-labelled compound require and also in the time required for sample preparation and NMR acquisition. Following the optimisation of the ring current method, it was applied to three sample sets of BC materials to address in detail three important aspects of BC composition: (i) the effect of temperature on BC; (ii) the effect of feedstock on BC; and (iii) the nature and variability of charcoal produced in natural fires. The parameter derived from the ring current technique, Δδ, was demonstrated to be a good measure of aromatic condensation. This was most evident for a thermosequence of twelve chestnut wood chars produced at temperatures from 200 to 1000°C, as it clearly captured the variations in char composition with increasing temperature. Through the use of the ring current method that it became clear that there are two distinct phases in charcoal formation: first an increase in aromaticity, and second a structural rearrangement creating condensed aromatic structures. The use of different feedstock resulted in critical differences in aromatic condensation between biochars produced at the same temperature. In particular, feedstocks with higher lignin contents, such as woody materials, were found to form more condensed aromatic structures with a higher degree of aromaticity compared to biochars from mineral-rich feedstocks (e.g. crop residues) and waste materials (e.g. manures, food waste and papermill waste). Lastly, the variability in chars produced in natural vegetation fires was gauged through the analysis of 53 natural chars collected from the soil surface six to thirty years after natural fires. The aromatic condensation was found to vary considerably among 4-5 char samples collected at each of the fire sites, despite efforts to sample only the most carbonized char from burnt-out tree stumps. This demonstrates that there is great degree of variability in the composition of the char produced in such fires, which is likely to be reflected in widely varying rates of char decomposition.
Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food and Wine, 2012

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Alyami, Mram Z. "Living Polycondensation: Synthesis of Well-Defined Aromatic Polyamide-Based Polymeric Materials." Thesis, 2016. http://hdl.handle.net/10754/621874.

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Chain growth condensation polymerization is a powerful tool towards the synthesis of well-defined polyamides. This thesis focuses on one hand, on the synthesis of well-defined aromatic polyamides with different aminoalkyl pendant groups with low polydispersity and controlled molecular weights, and on the other hand, on studying their thermal properties. In the first project, well-defined poly (N-octyl-p-aminobenzoate) and poly (N-butyl-p-aminobenzoate) were synthesized, and for the first time, their thermal properties were studied. In the second project, ethyl4-aminobenzoate, ethyl 4-octyl aminobenzoate and 4-(hydroxymethyl) benzoic acid were used as novel efficient initiators of ε-caprolactone with t-BuP2 as a catalyst. Macroinitiator and Macromonomer of poly (ε-caprolactone) were synthesized with ethyl 4-octyl aminobenzoate and ethyl 4-aminobenzoate as initiators to afford polyamide-block-poly (ε-caprolactone) and polyamide-graft-poly (ε-caprolactone) by chain growth condensation polymerization (CGCP). In the third project, a new study has been done on chain growth condensation polymerization to discover the probability to synthesize new polymers and studied their thermal properties. For this purpose, poly (N-cyclohexyl-p-aminobenzoate) and poly (N-hexyl-p-aminobenzoate) were synthesized with low polydispersity and controlled molecular weights.

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Книги з теми "Aromatic condensation"

Daszkiewicz, Zdzisław. Aromatyczne nitraminy: Synteza, struktura, właściwości, przegrupowanie. Opole: Wydaw. UO, 2004.

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Частини книг з теми "Aromatic condensation"

Keller, Rudolf. "Polyaromatic Hydrocarbons and the Condensation of Carbon in Stellar Winds." In Polycyclic Aromatic Hydrocarbons and Astrophysics, 387–97. Dordrecht: Springer Netherlands, 1987. http://dx.doi.org/10.1007/978-94-009-4776-4_37.

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Rusanov, Alexandre L., Dmitri Likhatchev, Petr V. Kostoglodov, Klaus Müllen, Markus Klapper, and Manfred Schmidt. "Proton-Exchanging Electrolyte Membranes Based on Aromatic Condensation Polymers." In Inorganic Polymeric Nanocomposites and Membranes, 83–134. Berlin, Heidelberg: Springer Berlin Heidelberg, 2005. http://dx.doi.org/10.1007/b104480.

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Kellman, Raymond, Robert F. Williams, George Dimotsis, Diana J. Gerbi, and Janet C. Williams. "Aromatic Substitution in Condensation Polymerization Catalyzed by Solid-Liquid Phase Transfer." In ACS Symposium Series, 128–42. Washington, DC: American Chemical Society, 1987. http://dx.doi.org/10.1021/bk-1987-0326.ch011.

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Nelson, D. A., J. A. Russell, and P. M. Molton. "Formation of Aromatic Compounds from Condensation Reactions of Cellulose Degradation Products—II." In Fundamentals of Thermochemical Biomass Conversion, 1039–50. Dordrecht: Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-009-4932-4_58.

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Wachter, Nanette M. "Using NMR To Investigate Products of Aldol Reactions: Identifying Aldol Addition versus Condensation Products or Conjugate Addition Products from Crossed Aldol Reactions of Aromatic Aldehydes and Ketones." In ACS Symposium Series, 91–102. Washington, DC: American Chemical Society, 2013. http://dx.doi.org/10.1021/bk-2013-1128.ch007.

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Matteson, D. S. "Condensation of Aromatic Aldehydes with Styrenes." In Boron Compounds, 1. Georg Thieme Verlag KG, 2005. http://dx.doi.org/10.1055/sos-sd-006-00183.

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Matteson, D. S. "Condensation of Aromatic Aldehydes with Arylacetylenes." In Boron Compounds, 1. Georg Thieme Verlag KG, 2005. http://dx.doi.org/10.1055/sos-sd-006-00184.

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Schantl, J. G. "Condensation of Bromonitromethane with Aromatic Aldehydes." In Three Carbon-Heteroatom Bonds: Ketenes and Derivatives, 1. Georg Thieme Verlag KG, 2006. http://dx.doi.org/10.1055/sos-sd-024-00327.

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Schantl, J. G. "Condensation of Halonitromethanes with Aromatic and Heteroaromatic Aldehydes." In Three Carbon-Heteroatom Bonds: Ketenes and Derivatives, 1. Georg Thieme Verlag KG, 2006. http://dx.doi.org/10.1055/sos-sd-024-00328.

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Lozano, Erika, Melissa M. Lewis-Bakker, and Lakshmi P. Kotra. "Synthetic Strategies and Biological Activities of 1,5-Disubstituted Pyrazoles and 2,5-Disubstituted Thiazoles." In Strategies Towards the Synthesis of Heterocycles and Their Applications [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.108923.

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Pyrazoles and thiazoles belong to 5-membered aromatic heterocycles called azoles. In addition to a nitrogen, pyrazoles contain an additional nitrogen in a 1,2 linkage and thiazoles contain a sulfur atom in a 1,3 linkage. These compounds are useful pharmacophores that offer a broad range of therapeutic applications. Pyrazoles can be synthesized by (i) the condensation of 1,3 dipolar compounds and alkenes/alkynes, (b) cyclocondensation of hydrazines and dicarbonyl reagents, and (c) multi-component reactions. Access to thiazoles is typically via (a) the condensation of α-haloketones with nucleophilic thioamides containing the N-C-S fragment, (b) a reaction between α-aminonitriles and various reactants containing an X-C-S fragment, and (c) a reaction of acylaminocarbonyls and phosphorus pentasulfide. This chapter will focus on the strategies and our perspectives on the synthesis of pyrazoles and thiazoles including derivatives at the 1,5 positions and 2, 4, 5 positions respectively, reported during 2015–2022. Additionally, their therapeutic and biological evaluations will be discussed.

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Тези доповідей конференцій з теми "Aromatic condensation"

Franconetti, Antonio, Dolores Lara-García, Pedro Dominguez-Rodriguez, and Francisca Cabrera-Escribano. "Structurally Complexes Aromatic Aldehydes on Knoevenagel Condensation Catalyzed by Chitosan Hydrogel Beads." In The 18th International Electronic Conference on Synthetic Organic Chemistry. Basel, Switzerland: MDPI, 2014. http://dx.doi.org/10.3390/ecsoc-18-a038.

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Paula, Bruno R. S. de, Dávila S. Zampieri, J. Augusto R. Rodrigues, and Paulo J. S. Moran. "The Knoevenagel condensation between ethyl 4- chloroacetoacetate and aromatic aldehydes in ionic liquids." In 14th Brazilian Meeting on Organic Synthesis. São Paulo: Editora Edgard Blücher, 2013. http://dx.doi.org/10.5151/chempro-14bmos-r0280-1.

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Hatcher, Patrick G., Hongmei Chen, Seyyedhadi Khatami, and Derek C. Waggoner. "Condensation and Polymerization Explain the Humification of Lignin into Aliphatic and Aromatic Structures in Soil." In 29th International Meeting on Organic Geochemistry. European Association of Geoscientists & Engineers, 2019. http://dx.doi.org/10.3997/2214-4609.201902860.

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Riesmeier, Elmar, Sylvie Honnet, and Norbert Peters. "Flamelet Modeling of Pollutant Formation in a Gas Turbine Combustion Chamber Using Detailed Chemistry for a Kerosene Model Fuel." In ASME 2002 Internal Combustion Engine Division Fall Technical Conference. ASMEDC, 2002. http://dx.doi.org/10.1115/icef2002-492.

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Combustion and pollutant formation in a gas turbine combustion chamber is investigated numerically using the Eulerian Particle Flamelet Model (EPFM). The code solving the unsteady flamelet equations is coupled to an unstructured CFD code providing solutions for the flow and mixture field from which the flamelet parameters can be extracted. Flamelets are initialized in the fuel rich region close to the fuel injectors of the combustor. They are represented by marker particles which are convected through the flow field. Each flamelet takes a different pathway through the combustor leading to different histories for the flamelet parameters. Equations for the probability of finding a flamelet at a certain position and time are additionally solved in the CFD code. To model the chemical properties of kerosene, a detailed reaction mechanism for a mixture of n-decane and 1,2,4-trimethylbenzene is used. It includes a detailed NOx submechanism and the build-up of polycyclic aromatic hydrocarbons (PAHs) up to four aromatic rings. The kinetically based soot model describes the formation of soot particles by inception, further growth by coagulation and condensation as well as surface growth and oxidation. Simulation results are compared to experimental data obtained on a high pressure rig. The influence of the model on pollutant formation is shown, and the effect of the number of flamelets on the model is investigated.

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Puduppakkam, Karthik V., Abhijit U. Modak, Chitralkumar V. Naik, Joaquin Camacho, Hai Wang, and Ellen Meeks. "A Soot Chemistry Model That Captures Fuel Effects." In ASME Turbo Expo 2014: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/gt2014-27123.

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A detailed chemistry model is necessary to simulate the effects of variations in fuel composition on soot emissions. In this work, we have developed a detailed chemistry model for the soot formation and oxidation chemistry, with a focus on the surface kinetics of the soot-particle. The model has been compared to a unique set of soot particle-size data measured in flames for several single-component fuels. Fuel components used in the experiments represent the chemical classes found in jet, gasoline, and diesel fuels, including n-heptane (representative of n-alkanes) and toluene (aromatic). Measurements were taken in burner-stabilized stagnation-flame (BSSF) experiments, which can be simulated well using the 1-dimensional BSSF flame model in CHEMKIN-PRO. Soot volume fraction and particle size distributions are modeled using the sectional method option for Particle Tracking, within CHEMKIN-PRO software. The well-characterized flow of the BSSF experiments allows the modeling to focus on the kinetics. Validated detailed reaction mechanisms for fuel combustion and PAH production, combined with the new soot surface-kinetics mechanism, were used in the simulations. Simulation results were compared to measurements for both particle size distributions and total soot volume fraction. Observed effects of fuel, temperature, pressure, equivalence ratio and residence time on the soot size distribution shape and soot quantity were reproduced by the model. The chemistry in the soot surface model includes particle nucleation, growth through the HACA (hydrogen-abstraction/carbon-addition) and PAH-condensation (polycyclic aromatic hydrocarbons) pathways, as well as soot-oxidation pathways. In addition to soot chemistry, the physics of particle coagulation and aggregation were included in the model. The results demonstrate the ability of well-validated chemistry to predict both dramatic and subtle effects related to soot mass and soot particle size.

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Sun, Mingshan, and Zhiwen Gan. "A Numerical Study on the Influence of Hydrogen Addition on Soot Formation in a Laminar Aviation Kerosene (Jet A1) Flame at Elevated Pressure." In ASME Turbo Expo 2021: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/gt2021-59203.

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Abstract The hydrogen addition is a potential way to reduce the soot emission of aviation kerosene. The current study analyzed the effect of hydrogen addition on aviation kerosene (Jet A1) soot formation in a laminar flame at elevated pressure to obtain a fundamental understanding of the reduced soot formation by hydrogen addition. The soot formation of flame was simulated by CoFlame code. The soot formation of kerosene-nitrogen-air, (kerosene + replaced hydrogen addition)-nitrogen-air, (kerosene + direct hydrogen addition)-nitrogen-air and (kerosene + direct nitrogen addition)-nitrogen-air laminar flames were simulated. The calculated pressure includes 1, 2 and 5 atm. The hydrogen addition increases the peak temperature of Jet A1 flame and extends the height of flame. The hydrogen addition suppresses the soot precursor formation of Jet A1 by physical dilution effect and chemical inhibition effect, which weaken the poly-aromatic hydrocarbon (PAH) condensation process and reduce the soot formation. The elevated pressure significantly accelerates the soot precursor formation and increases the soot formation in flame. Meanwhile, the ratio of reduced soot volume fraction to base soot volume fraction by hydrogen addition decreases with the increase of pressure, indicating that the elevated pressure weakens the suppression effect of hydrogen addition on soot formation in Jet A1 flame.

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Duvvuri, Pavan P., Sujith Sukumaran, Rajesh K. Shrivastava, and Sheshadri Sreedhara. "Modeling the Effect of Parametric Variations on Soot Particle Size Distribution in a Diesel Engine." In ASME 2018 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/icef2018-9699.

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Stringent emission legislations, increasing environmental and health issues have driven extensive research in combustion engines to control pollutants. Modeling of emissions offers a cost saving alternative to experimental analysis for combustion chamber design and optimization. Soot modeling in diesel engines has evolved over four decades from simple empirical relations to detailed kinetics involving polycyclic aromatic hydrocarbons (PAH) and complex particle dynamics. Although numerical models have been established for predicting soot mass for parametric variations, there is a lack of modeling studies for predicting soot particle size distribution for parametric variations. This becomes important considering the inclusion of limits on soot particle count in recent emission norms. The current work aims at modeling the soot particle size distribution inside a heavy duty diesel engine and validating the results for a parametric variation of injection pressure and intake temperature. Closed cycle combustion simulations have been performed using CONVERGE, a 3D computational fluid dynamics (CFD) code. A sectional soot model coupled with gas phase kinetics has been used with source terms for inception, condensation, surface reactions and coagulation. Numerical predictions for soot mass and particle size distribution at the exhaust show good agreement with experimental data after increasing the transition regime collision frequency by a factor of 100.

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Aslanidis, Panagiotis, Dimitris Marinakis, Tina Puntervold, Vasilis Gaganis, and Nikolaos Varotsis. "Density Changes at Supercritical and Near-Critical Conditions by Increasing CO2 Content in Synthetic Hydrocarbon Mixtures – A Comparison Between Experiments and Simulation Predictions." In SPE EuropEC - Europe Energy Conference featured at the 83rd EAGE Annual Conference & Exhibition. SPE, 2022. http://dx.doi.org/10.2118/209663-ms.

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Abstract Carbon dioxide (CO2) injection is a well-known EOR-method to reduce residual oil in the pore network of oil reservoirs. It is also increasingly used as a means of mitigating the greenhouse gas emissions problem by storing it in geological formations. A key parameter to such attempts is the density of the rich CO2 mixture, which is formed downhole in the injection well, since it affects the swelling potential, oil formation volume factor, viscosity, hydrostatic gradient, fluid distribution and formation pore pressure. The density of the crude oil-CO2 mixture depends on the pressure-temperature conditions, the CO2 concentration and the dominant hydrogen compounds in the crude oil, i.e. whether they are aliphatics, aromatics, or naphtenics (cyclic structures). The PVT properties of the different CO2-hydrocarbon mixtures vary greatly and the available experimental data for tuning PVT simulators are scarce, especially for ternary mixtures at high pressures and CO2 concentrations. This study investigates the effect of CO2 concentration on the density of ternary mixtures containing CO2, methane, and a pure liquid hydrocarbon, which is either an alkane, aromatic or cycloalkane compound. The liquid hydrocarbons used in the study were normal heptane (n-C7), toluene (Tol) and cyclohexane (c-C6). The measurements were conducted at variable compositions, at temperatures of 50, 70, and 90 °C, and at pressures ranging between 100 and 517 bar. The ternary mixtures were: Methane, toluene and CO2 at 1:1 molar ratio and CO2 concentrations of 14%, 27% and 72%, Methane, cyclohexane and CO2 at 1:1 molar ratio and CO2 concentrations of 19%, 47% and 68%. Methane, n-heptane and CO2 at constant molar hydrocarbon ratio (C1/n-C7) of 2:1 and varying CO2 concentrations of 23% and 75%, Some of the rich CO2 mixtures exhibited retrograde condensation behaviour at high temperatures. The results were compared against predictions from an EoS model (Peng Robinson Equation of State), coupled with volume shift parameters. The comparison between the simulation calculations and the experimental data indicated good agreement in the densities, but significant deviations in the boiling point pressures (Pb). As a result, the EoS model can be safely used to predict the CO2 mass storage potential of reservoirs of known pore volume such as the depleted ones.

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Sun, Mingshan, and Zhiwen Gan. "A Numerical and Experimental Study of Soot Precursor and Primary Particle Size of N-Butylbenzene in Laminar Flame." In ASME 2021 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/icef2021-67749.

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Abstract The current study analyzed the soot precursor of the n-butylbenzene found in diesel and kerosene in laminar flame, and integrated the corresponding poly-aromatic hydrocarbon (PAH) growth mechanism with the popular n-butylbenzene oxidation mechanisms to improve the soot formation prediction of n-butylbenzene. The size of soot precursor was determined by the fringe length in the core of soot particle since the nanostructure of the core of soot particle is similar with that of nascent soot particle formed by soot precursor nucleation. The geometric mean fringe length in core of soot particles was measured to be 0.67 nm approximating to the size of five-ringed PAH (A5). An A5 growth mechanism was added on a popular n-butylbenzene mechanism, and the combined mechanism was further reduced. After validation by the ignition delay time in literature, the combined mechanism was then validated by the primary particle diameter in laboratory and soot volume fraction of n-propylbenzene in literature. The calculated soot precursor concentration and PAH condensation rate of the combined mechanism are smaller than that of the base mechanism. The simulated primary soot particle diameter of proposed combined mechanism agrees well with the measure primary soot particle diameter. Comparing to the simulated soot volume fraction of base n-butylbenzene mechanism, the simulated soot volume fraction of proposed combined n-butylbenzene-A5 mechanism agrees well with the measure soot volume fraction of n-propylbenzene in literature. This study provides certain support for further investigation of soot formation of n-butylbenzene and its relative fuel like diesel and kerosene.

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Mininni, Giuseppe, Dario Marani, Camilla Maria Braguglia, Ettore Guerriero, and Andrea Sbrilli. "Behavior of Organic and Inorganic Micropollutants in Chlorine Spiked Sludge Incineration by a Circulating Fluidized Bed Furnace." In 17th International Conference on Fluidized Bed Combustion. ASMEDC, 2003. http://dx.doi.org/10.1115/fbc2003-105.

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The effects of combustion and feeding conditions on Polycyclic Aromatic Hydrocarbons (PAH) and PCDD/F formation and appearance in the emissions at the stack during sludge incineration are discussed in this paper. Partitioning in the solid streams of Cd, Cr, Cu, Mn, Ni, Pb and Zn is also analyzed. Tests were performed on a demonstrative plant equipped with a fluidized bed furnace (FBF) using sewage sludge either as is or spiked with chlorinated organic compounds (tetrachloroethylene or a mixture of tetrachloroethylene, chlorobenzene and toluene) to study the chlorine effect on the presence of micropollutants in the different streams. Exhaust gases were sampled both before and after the treatment system (bag house and wet scrubber). In the untreated flue gas the highest values of PCDD/F and PAH were detected when the afterburning chamber was not in use or operating at low temperatures. Operation of the afterburning chamber at temperature higher than 850–900 °C was sufficient to keep organic micropollutants concentrations in the untreated flue gas at reasonably low levels. No significant correlation of the operating conditions with emissions at the stack was found. High copper concentration in the feed enhanced PCDD/F formation, with exception of tests carried out with high afterburning temperature. The homologue profile of PCDD/F and PAH depended on test conditions. Preferential accumulation of heavy metals in the filter ash with respect to cyclone ash was quantified in terms of an enrichment factor. Out of the seven metals considered, only Cd and Pb undergo significant enrichment in the filter ash. The enrichment increased with increasing chlorine content of the feed. In contrast, Cu, Cr, Mn, Ni, and Zn behaved as refractory (non-volatile) elements even at high chlorine dosage. In accordance with the widely accepted hypothesis that metal enrichment is due to metal vaporization in the combustion chamber and subsequent condensation onto the filter ash particles, a thermodynamic model of the combustion process was able to satisfactorily predict the different metal behavior and the effect of chlorine dosage on metal enrichment.

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