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1.
Org Biomol Chem ; 20(9): 1794-1827, 2022 03 02.
Artículo en Inglés | MEDLINE | ID: mdl-35147631

RESUMEN

The enantioselective and diastereoselective hydrogenation of N-heteroaromatic compounds is an efficient strategy to access chirally enriched cyclic heterocycles, which often possess highly bio-active properties. This strategy, however, has only been established in recent times. This is in part due to the challenges of the high stability of the aromatic compounds and the presence of heteroatoms that have the potential to poison the chiral catalysts. Additionally, N-heteroaromatic compounds are a structurally diverse family of substrates, each group showing distinct reactivity in hydrogenation. Advances in recent years have allowed various N-heteroaromatic compounds, including pyridines, indoles, quinolines, isoquinolines, quinoxalines and imidazoles, to be hydrogenated with good to excellent enantioselectivity under appropriate reaction conditions. Transition-metal catalysis, utilising iridium, ruthenium, rhodium, and palladium complexes, has been found to play an important role in this field. More recently, organocatalysis has been shown to be efficient for the hydrogenation of certain N-heteroaromatic compounds. This review provides an analysis of the recent developments in the enantioselective and diastereoselective hydrogenation of N-heteroaromatic compounds. The importance of these molecules and their applications to drug discovery has been highlighted throughout the review.


Asunto(s)
Compuestos Heterocíclicos/síntesis química , Hidrocarburos Aromáticos/síntesis química , Compuestos Heterocíclicos/química , Hidrocarburos Aromáticos/química , Hidrogenación , Estructura Molecular , Estereoisomerismo
2.
Bioorg Med Chem Lett ; 54: 128443, 2021 12 15.
Artículo en Inglés | MEDLINE | ID: mdl-34763081

RESUMEN

Here we report the first small-molecule inhibitors of human sulfide:quinone oxidoreductase (SQOR) that decrease the rate of breakdown of hydrogen sulfide (H2S), a potent cardioprotective signaling molecule. SQOR is a mitochondrial membrane-bound protein that catalyzes a two-electron oxidation of H2S to sulfane sulfur (S0), using glutathione (or sulfite) and coenzyme Q (CoQ) as S0 and electron acceptor, respectively. Inhibition of SQOR may constitute a new approach for the treatment of heart failure with reduced ejection fraction. Starting from top hits identified in a high-throughput screen, we conducted SAR development guided by docking of lead candidates into our crystal structure of SQOR. We identified potent SQOR inhibitors such as 19 which has an IC50 of 29 nM for SQOR inhibition and favorable pharmacokinetic and ADME properties required for in vivo efficacy testing.


Asunto(s)
Inhibidores Enzimáticos/farmacología , Hidrocarburos Aromáticos/farmacología , Oxidorreductasas actuantes sobre Donantes de Grupos Sulfuro/antagonistas & inhibidores , Bibliotecas de Moléculas Pequeñas/farmacología , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Humanos , Hidrocarburos Aromáticos/síntesis química , Hidrocarburos Aromáticos/química , Estructura Molecular , Oxidorreductasas actuantes sobre Donantes de Grupos Sulfuro/metabolismo , Bibliotecas de Moléculas Pequeñas/síntesis química , Bibliotecas de Moléculas Pequeñas/química , Relación Estructura-Actividad
3.
Chem Commun (Camb) ; 57(44): 5442-5445, 2021 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-33949517

RESUMEN

A nitrogen replacement process that directly incorporates the 15N atom of glycine-15N into anilines was reported. The process involves a Csp2-N bond cleavage of anilines driven by dearomatization and a Csp3-N bond cleavage of glycine-15N driven by aromatization. A variety of 15N-labeled aromatic heterocycles can be prepared via this process.


Asunto(s)
Compuestos de Anilina/química , Glicina/química , Compuestos Heterocíclicos/síntesis química , Hidrocarburos Aromáticos/síntesis química , Compuestos Heterocíclicos/química , Hidrocarburos Aromáticos/química , Estructura Molecular , Isótopos de Nitrógeno
4.
ChemSusChem ; 14(8): 1821-1824, 2021 Apr 22.
Artículo en Inglés | MEDLINE | ID: mdl-33651919

RESUMEN

A general, sustainable dearomatization reaction for nitrogen-containing heterocycles was developed. Under solvent free conditions and without catalyst, the biorenewable methyl coumalate (MC) reacted as an efficient C3 partner to convert nine types of basic aromatic rings into their pyrido[1,2-a] fused derivatives in good to excellent yields. The fluorescence properties of some of the products were harnessed to conjugate fluorescent tags to bovine serum albumin (BSA) and immunoglobulin G.


Asunto(s)
Colorantes Fluorescentes/química , Compuestos Heterocíclicos/síntesis química , Hidrocarburos Aromáticos/síntesis química , Anisoles/química , Benzofuranos/química , Catálisis , Reacción de Cicloadición , Inmunoglobulina G/química , Indoles/química , Estructura Molecular , Imagen Óptica , Pironas/química , Pirroles/química , Albúmina Sérica Bovina/química , Solventes/química
5.
Molecules ; 26(2)2021 Jan 18.
Artículo en Inglés | MEDLINE | ID: mdl-33477568

RESUMEN

This review gives an up-to-date overview of the different ways (routes) to the synthesis of coumarin (benzopyrone)-fused, five-membered aromatic heterocycles with one heteroatom, built on the pyrone moiety. Covering 1966 to 2020.


Asunto(s)
Cumarinas/química , Compuestos Heterocíclicos/síntesis química , Hidrocarburos Aromáticos/síntesis química , Pironas/química
6.
ChemMedChem ; 16(6): 976-988, 2021 03 18.
Artículo en Inglés | MEDLINE | ID: mdl-33369214

RESUMEN

Astacin metalloproteinases, in particular meprins α and ß, as well as ovastacin, are emerging drug targets. Drug-discovery efforts have led to the development of the first potent and selective inhibitors in the last few years. However, the most recent compounds are based on a highly flexible tertiary amine scaffold that could cause metabolic liabilities or decreased potency due to the entropic penalty upon binding to the target. Thus, the aim of this study was to discover novel conformationally constrained scaffolds as starting points for further inhibitor optimization. Shifting from flexible tertiary amines to rigid heteroaromatic cores resulted in a boost in inhibitory activity. Moreover, some compounds already exhibited higher activity against individual astacin proteinases compared to recently reported inhibitors and also a favorable off-target selectivity profile, thus qualifying them as very suitable chemical probes for target validation.


Asunto(s)
Aminas/farmacología , Antineoplásicos/farmacología , Descubrimiento de Drogas , Hidrocarburos Aromáticos/farmacología , Metaloendopeptidasas/antagonistas & inhibidores , Metaloproteasas/antagonistas & inhibidores , Inhibidores de Proteasas/farmacología , Aminas/síntesis química , Aminas/química , Antineoplásicos/síntesis química , Antineoplásicos/química , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Ensayos de Selección de Medicamentos Antitumorales , Humanos , Hidrocarburos Aromáticos/síntesis química , Hidrocarburos Aromáticos/química , Metaloendopeptidasas/metabolismo , Metaloproteasas/metabolismo , Estructura Molecular , Inhibidores de Proteasas/síntesis química , Inhibidores de Proteasas/química , Proteínas Recombinantes/metabolismo , Relación Estructura-Actividad , Células Tumorales Cultivadas
7.
J Am Chem Soc ; 143(2): 964-972, 2021 01 20.
Artículo en Inglés | MEDLINE | ID: mdl-33373207

RESUMEN

2,4,5,6-Tetrakis(3,6-di-tert-butyl-9H-carbazol-9-yl)isophthalonitrile (4CzIPN-tBu) was developed as a photocatalyst for the phosphorus-radical-initiated cascade cyclization reaction of isocyanides. By using 4CzIPN-tBu as catalyst, we developed a visible-light-induced proton-coupled electron transfer strategy for the generation of phosphorus-centered radicals, via which a wide range of phosphorylated phenanthridines, quinolines, and benzothiazoles were successfully constructed.


Asunto(s)
Compuestos Heterocíclicos/síntesis química , Hidrocarburos Aromáticos/síntesis química , Protones , Catálisis , Transporte de Electrón , Compuestos Heterocíclicos/química , Hidrocarburos Aromáticos/química , Estructura Molecular , Fosforilación
8.
Molecules ; 25(20)2020 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-33076581

RESUMEN

The synthesis, isolation and full characterization of ion pairs between alkaline metal ions (Li+, Na+, K+) and mono-anions and dianions obtained from 5H-dibenzo[a,d]cycloheptenyl (C15H11 = trop) is reported. According to Nuclear Magnetic Resonance (NMR) spectroscopy, single crystal X-ray analysis and Density Functional Theory (DFT) calculations, the trop‒ and trop2-• anions show anti-aromatic properties which are dependent on the counter cation M+ and solvent molecules serving as co-ligands. For comparison, the disodium and dipotassium salt of the dianion of dibenzo[a,e]cyclooctatetraene (C16H12 = dbcot) were prepared, which show classical aromatic character. A d8-Rh(I) complex of trop- was prepared and the structure shows a distortion of the C15H11 ligand into a conjugated 10π -benzo pentadienide unit-to which the Rh(I) center is coordinated-and an aromatic 6π electron benzo group which is non-coordinated. Electron transfer reactions between neutral and anionic trop and dbcot species show that the anti-aromatic compounds obtained from trop are significantly stronger reductants.


Asunto(s)
Compuestos Heterocíclicos/química , Hidrocarburos Aromáticos/química , Iones/química , Metales/química , Álcalis/química , Aniones/síntesis química , Aniones/química , Cristalografía por Rayos X , Electrones , Compuestos Heterocíclicos/síntesis química , Hidrocarburos Aromáticos/síntesis química , Iones/síntesis química , Ligandos , Metales/síntesis química , Estructura Molecular
9.
Nat Commun ; 11(1): 2706, 2020 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-32483217

RESUMEN

Aldehyde is one of most synthetically versatile functional groups and can participate in numerous chemical transformations. While a variety of simple aromatic aldehydes are commercially available, those with a more complex substitution pattern are often difficult to obtain. Benzylic oxygenation of methylarenes is a highly attractive method for aldehyde synthesis as the starting materials are easy to obtain and handle. However, regioselective oxidation of functionalized methylarenes, especially those that contain heterocyclic moieties, to aromatic aldehydes remains a significant challenge. Here we show an efficient electrochemical method that achieves site-selective electrooxidation of methyl benzoheterocycles to aromatic acetals without using chemical oxidants or transition-metal catalysts. The acetals can be converted to the corresponding aldehydes through hydrolysis in one-pot or in a separate step. The synthetic utility of our method is highlighted by its application to the efficient preparation of the antihypertensive drug telmisartan.


Asunto(s)
Acetales/química , Aldehídos/química , Técnicas Electroquímicas/métodos , Hidrocarburos Aromáticos/química , Modelos Químicos , Acetales/síntesis química , Aldehídos/síntesis química , Amidinas/química , Bencimidazoles/química , Catálisis , Hidrocarburos Aromáticos/síntesis química , Hidrólisis , Estructura Molecular , Oxidantes/química , Oxidación-Reducción
10.
Biochem Biophys Res Commun ; 533(2): 209-214, 2020 12 03.
Artículo en Inglés | MEDLINE | ID: mdl-32376009

RESUMEN

A mild reaction for DNA-compatible, palladium promoted Suzuki-Miyaura cross-coupling reaction of potassium Boc-protected aminomethyltrifluoroborate with DNA-conjugated aryl bromides has been developed efficiently. This novel DNA encoded chemistry reaction proceeded well with a wide range of functional group tolerance, including aryl bromides and heteroaryl bromides. Further, the utility our DNA conjugated aminomethylated arene products is demonstrated by reaction with various types of reagents (including amide formation with carboxylic acids, alkylation with aldehydes, and carbamoylation with amines) as would be desired for the production of a DNA encoded library.


Asunto(s)
Boratos/química , Bromuros/química , ADN/química , Hidrocarburos Aromáticos/química , Aminación , Boratos/síntesis química , Bromuros/síntesis química , Catálisis , Técnicas Químicas Combinatorias , ADN/síntesis química , Halogenación , Hidrocarburos Aromáticos/síntesis química , Metilación , Paladio/química , Potasio/química , Bibliotecas de Moléculas Pequeñas/síntesis química , Bibliotecas de Moléculas Pequeñas/química
11.
J Am Chem Soc ; 142(23): 10477-10484, 2020 06 10.
Artículo en Inglés | MEDLINE | ID: mdl-32379433

RESUMEN

The palladium-catalyzed, α-selective hydroarylation of acrylates and acrylamides is reported. Under optimized conditions, this method is highly tolerant of a wide range of substrates including those with base sensitive functional groups and/or multiple enolizable carbonyl groups. A detailed mechanistic study was undertaken, and the high selectivity of this transformation was shown to be enabled by the formation of a [PdII(Ar)(H)] intermediate, which performs selective hydride insertion into the ß-position of α,ß-unsaturated carbonyl compounds.


Asunto(s)
Acrilamidas/química , Acrilatos/química , Hidrocarburos Aromáticos/síntesis química , Cetonas/síntesis química , Catálisis , Halogenación , Hidrocarburos Aromáticos/química , Cetonas/química , Estructura Molecular , Paladio/química , Estereoisomerismo
12.
Biochem Biophys Res Commun ; 533(2): 201-208, 2020 12 03.
Artículo en Inglés | MEDLINE | ID: mdl-32414574

RESUMEN

A catalytic manifold that enables photoredox cross-electrophile coupling of alkyl bromides with DNA-tagged aryl iodides in aqueous solution is presented. This metallaphotoredox transformation was aided by the identification of a new pyridyl bis(carboxamidine) ligand, which proved critical to the nickel catalytic cycle. The described C(sp2)-C(sp3) coupling tolerates a wide range of both DNA-tagged aryl iodides as well as alkyl bromides. Importantly, this reaction was optimized for parallel synthesis, which is a paramount prerequisite for the preparation of combinatorial libraries, by using a 96-well plate-compatible blue LED array as the light source. Therefore, this mild and DNA-compatible transformation is well positioned for the construction of DNA-encoded libraries.


Asunto(s)
Alcanos/química , Bromuros/química , ADN/química , Hidrocarburos Aromáticos/química , Yoduros/química , Alcanos/síntesis química , Alquilación , Bromuros/síntesis química , Catálisis , Técnicas Químicas Combinatorias , ADN/síntesis química , Hidrocarburos Aromáticos/síntesis química , Yoduros/síntesis química , Ligandos , Níquel/química , Oxidación-Reducción , Bibliotecas de Moléculas Pequeñas/síntesis química , Bibliotecas de Moléculas Pequeñas/química
13.
J Sep Sci ; 43(14): 2842-2849, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32320521

RESUMEN

In this study, the new and efficient three-dimensional network porous aromatic frameworks materials called Silica-PAFs-a, Florisil-PAFs-a, Silica-PAFs-b, and Florisil-PAFs-b were first synthesized. The properties of materials were analyzed by five characterization methods. The materials were used as adsorbents in pipette-tip solid-phase extraction for the effective determination of carbendazim and thiabendazole in spinach sample. Meanwhile, the obtained materials were tested by static adsorption and dynamic adsorption. The result showed that the specific surface area of materials greatly increased after introducing three-dimensional network porous aromatic frameworks. Microstructural modification exposed a large number of amino reactive groups that made them have a better adsorption amount for the two targets. The calibration graphs of carbendazim and thiabendazole in methanol were linear over 0.10-300.0 µg/mL, and the limits of detection and quantification were 0.00546 and 0.0182 µg/mL, and 0.00741 and 0.0247µg/mL respectively. A reliable analytical method was developed for recognition targets in spinach sample by Silica-PAFs-b with satisfactory extraction recoveries (96.25 and 100.51%). The proposed method using the material was applied for trace analysis of the carbendazim and thiabendazole residue.


Asunto(s)
Bencimidazoles/análisis , Carbamatos/análisis , Hidrocarburos Aromáticos/química , Spinacia oleracea/química , Tiabendazol/análisis , Triazinas/química , Hidrocarburos Aromáticos/síntesis química , Silicatos de Magnesio/química , Estructura Molecular , Tamaño de la Partícula , Porosidad , Dióxido de Silicio/química , Propiedades de Superficie
14.
Angew Chem Int Ed Engl ; 59(19): 7425-7429, 2020 05 04.
Artículo en Inglés | MEDLINE | ID: mdl-32068943

RESUMEN

Expanding the toolbox of C-H functionalization reactions applicable to the late-stage modification of complex molecules is of interest in medicinal chemistry, wherein the preparation of structural variants of known pharmacophores is a key strategy for drug development. One manifold for the functionalization of aromatic molecules utilizes diazo compounds and a transition-metal catalyst to generate a metallocarbene species, which is capable of direct insertion into an aromatic C-H bond. However, these high-energy intermediates can often require directing groups or a large excess of substrate to achieve efficient and selective reactivity. Herein, we report that arene cation radicals generated by organic photoredox catalysis engage in formal C-H functionalization reactions with diazoacetate derivatives, furnishing sp2 -sp3 coupled products with moderate-to-good regioselectivity. In contrast to previous methods utilizing metallocarbene intermediates, this transformation does not proceed via a carbene intermediate, nor does it require the presence of a transition-metal catalyst.


Asunto(s)
Alquilación , Fotoquímica , Catálisis , Cationes , Compuestos de Diazonio/síntesis química , Desarrollo de Medicamentos , Radicales Libres , Hidrocarburos Aromáticos/síntesis química , Metales/química , Metano/análogos & derivados
15.
Acc Chem Res ; 53(1): 45-61, 2020 01 21.
Artículo en Inglés | MEDLINE | ID: mdl-31850730

RESUMEN

The importance of sustainable and green synthetic protocols for the synthesis of fine chemicals has rapidly increased during the last decades in an effort to reduce the use of fossil fuels and other finite resources. The replacement of common reagents by electricity provides a cost- and atom-efficient, environmentally friendly, and inherently safe access to novel synthetic routes. The selective formation of carbon-carbon bonds between two distinct substrates is a crucial tool in organic chemistry. This fundamental transformation enables access to a broad variety of complex molecular architectures. In particular, the aryl-aryl bond formation has high significance for the preparation of organic materials, drugs, and natural products. Besides well-known and well-established reductive- and oxidative-reagent-mediated or transition-metal-catalyzed coupling reactions, novel synthetic protocols have arisen, which require fewer steps than conventional synthetic approaches. Electroorganic conversions can be categorized according to the nature of the electron transfer processes occurring. Direct transformations at inert electrode materials are environmentally benign and cost-effective, whereas catalytic processes at active electrodes and mediated electrosynthesis using an additional soluble reagent can have beneficial properties in terms of selectivity and reactivity. In general, these conversions require challenging optimization of the reaction parameters and the appropriate cell design. Galvanostatic reactions enable fast conversions with a rather simple setup, whereas potentiostatic electrolysis may enhance selectivity. This Account discusses the development of seminal carbon-carbon bond formations over the past two decades, focusing on phenols leading to precursors for ligands in, e.g., hydroformylation reaction. A key element in the success of these electrochemical transformations is the application of electrochemically inert, non-nucleophilic, highly fluorinated alcohols such as 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), which exhibit a large potential window for transformations and enable selective cross-coupling reactions. This selectivity is based on the capability of HFIP to stabilize organic radicals. Inert, carbon-based and metal-free electrode materials like graphite or boron-doped diamond (BDD) open up novel electroorganic pathways. Furthermore, novel active electrode materials have been developed to enable intra- and intermolecular dehydrogenative coupling reactions of electron-rich aryls. The application of 2,2'-biphenol derivatives as ligand components for catalysts requires reactions to be carried out on larger scale. In order to achieve this, continuous flow transformations have been established to overcome the drawbacks of heat transfer, overconversion, and conductivity. Modular cell designs enable the transfer of a broad variety of electroorganic conversions into continuous processes. Recent results demonstrate the application of organic electrochemistry to natural product synthesis of the pharmaceutically relevant opiate alkaloids (-)-thebaine or (-)-oxycodone.


Asunto(s)
Técnicas Electroquímicas , Hidrocarburos Aromáticos/síntesis química , Hidrocarburos Aromáticos/química , Hidrogenación , Conformación Molecular
16.
J Org Chem ; 84(18): 11612-11622, 2019 09 20.
Artículo en Inglés | MEDLINE | ID: mdl-31433183

RESUMEN

An operationally simple nickel-catalyzed hydroarylation reaction for alkynes is described. This three-component coupling reaction utilizes commercially available alkynes and aryl bromides, along with water and Zn. An air-stable and easily synthesized Ni(II) precatalyst is the only entity used in the reaction that is not commercially available. This reductive cross-coupling reaction displays a fairly unusual anti selectivity when aryl bromides with ortho substituents are used. In addition to optimization data and a preliminary substrate scope, complementary experiments including deuterium labeling studies are used to provide a tentative catalytic mechanism. We believe this report should inspire and inform other Ni-catalyzed carbofunctionalization reactions.


Asunto(s)
Alquinos/química , Hidrocarburos Aromáticos/síntesis química , Hidrocarburos Bromados/química , Níquel/química , Agua/química , Complejos de Coordinación/química , Hidrocarburos Aromáticos/química , Estructura Molecular , Oxidación-Reducción , Estereoisomerismo
17.
J Am Chem Soc ; 141(33): 13203-13211, 2019 08 21.
Artículo en Inglés | MEDLINE | ID: mdl-31369264

RESUMEN

Fluorinated organic molecules are pervasive within the pharmaceutical and agrochemical industries due to the range of structural and physicochemical properties that fluorine imparts. Currently, the most abundant methods for the synthesis of the aryl-CF2 functionality have relied on the deoxyfluorination of ketones and aldehydes using expensive and poorly atom economical reagents. Here, we report a general method for the synthesis of aryl-CF2R and aryl-CF2H compounds through activation of the corresponding trifluoromethyl arene precursors. This strategy is enabled by an endergonic electron transfer event that provides access to arene radical anions that lie outside of the catalyst reduction potential. Fragmentation of these reactive intermediates delivers difluorobenzylic radicals that can be intercepted by abundant alkene feedstocks or a hydrogen atom to provide a diverse array of difluoalkylaromatics.


Asunto(s)
Flúor/química , Hidrocarburos Aromáticos/química , Alquenos/síntesis química , Alquenos/química , Alquilación , Carbono/química , Fluoruros/síntesis química , Fluoruros/química , Halogenación , Hidrocarburos Aromáticos/síntesis química , Metilación
18.
Angew Chem Int Ed Engl ; 58(37): 13149-13154, 2019 09 09.
Artículo en Inglés | MEDLINE | ID: mdl-31323171

RESUMEN

Despite a growing interest in CHF2 in medicinal chemistry, there is a lack of efficient methods for the insertion of CHF18 F into druglike compounds. Herein described is a photoredox flow reaction for 18 F-difluoromethylation of N-heteroaromatics that are widely used in medicinal chemistry. Following the two-step synthesis for a new 18 F-difluoromethylation reagent, the photoredox reaction is completed within two minutes and proceeds by C-H activation, circumventing the need for pre-functionalization of the substrate. The method is operationally simple and affords straightforward access to radiolabeled N-heteroaromatics with high molar activity suitable for biological in vivo studies and clinical application.


Asunto(s)
Radioisótopos de Flúor/química , Hidrocarburos Aromáticos/química , Halogenación , Hidrocarburos Aromáticos/síntesis química , Metilación , Oxidación-Reducción , Tomografía de Emisión de Positrones/métodos , Radioquímica
19.
Bioresour Technol ; 278: 66-72, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-30682638

RESUMEN

Catalytic pyrolysis of lignin over a dual-catalyst system of modified red mud and HZSM-5 was carried out in a bench-scale micro-reactor. Effects of pyrolysis temperature, modified red mud to HZSM-5 ratio, catalysts to lignin ratio on the yield of products and selectivity of aromatic hydrocarbons were investigated. Results indicated that 550 °C was the optimal pyrolysis temperature with the maximal yield of bio-oil (20.16 wt%). At a modified red mud to HZSM-5 ratio of 1:1, the content of monocyclic aromatic hydrocarbons (MAHs) increased to 41.27% whereas that of polycyclic aromatic hydrocarbons (PAHs) decreased to 22.65%. Likewise, at a catalysts to lignin ratio of 2:1, a higher content of MAHs was produced with a decreased content of PAHs. The cascade dual-catalyst system may serve as an efficient approach to disposing lignin and red mud wastes with significant environmental impact. Besides, this study provides a solution for the valorization of lignin-rich resources.


Asunto(s)
Hidrocarburos Aromáticos/síntesis química , Lignina/química , Catálisis , Calor , Hidrocarburos Aromáticos/química , Aceites de Plantas/química , Polifenoles/química , Pirólisis
20.
Bioresour Technol ; 272: 407-414, 2019 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-30388578

RESUMEN

Catalytic fast pyrolysis (CFP) of torrefied corn cob using Ni-modified hierarchical ZSM-5 catalyst was conducted in this study. The prepared catalysts were characterized by N2 adsorption and desorption (N2-BET), X-ray diffraction (XRD), and temperature-programmed desorption of NH3 (NH3-TPD). NaOH solution treatment resulted in the lower peak intensities of hierarchical ZSM-5 catalyst in the XRD patterns while Ni modification improved the catalyst framework. In addition, NaOH solution treatment created some mesopores or macropores, but the incorporation of Ni reduced BET surface area and volume of micropores. Though the addition of Ni lowered the acidity of catalyst, Ni-modified hierarchical ZSM-5 catalyst led to higher yields and of aromatic hydrocarbons. What is more, hierarchical ZSM-5 catalysts significantly improved the selectivities of mono-aromatics. Kinetic analysis shows that CFP of torrefied corn cob was second-order reaction and the addition of Ni can obtain a lower activation energy compared with hierarchical ZSM-5 catalyst.


Asunto(s)
Biocatálisis , Hidrocarburos Aromáticos/síntesis química , Zea mays/metabolismo , Cinética , Níquel , Pirólisis , Temperatura , Factores de Tiempo , Difracción de Rayos X
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