119-32-4Relevant articles and documents
Pd-Fe/SiO2 Catalysts in the Hydrogenation of 2,4-Dinitrotoluene
Pinna, F.,Selva, M.,Signoretto, M.,Strukul, G.,Boccuzzi, F.,et al.
, p. 356 - 367 (1994)
Pd-Fe/SiO2 bimetallic catalysts with a constant amount of Pd and a different Fe/Pd ratio were prepared by sequential wet impregnation and the hydrogenation of 2,4-dinitrotoluene was carried out at 25 deg C in a batch reactor.The presence of Fe enhances the Pd catalytic activity.The formation of a dispersed Pd-Fe alloy was evidenced through X-ray powder diffraction and is consisted with the data observed by FTIR analysis, TPR, and chemisorption features.The increase of the Fe total content of the catalysts results in the increase of the dispersion of the metallic phase and in the presence of partially oxidized Fe species.FTIR analysis shows that nitrocompounds chemisorb mainly on the support rather than on the metal surface.It is suggested that the Pd-Fe alloy formation is responsible for the increase of the catalytic activity because of a cooperative effect of Fe in the hydrogen transfer step.
Preparation and catalytic performance of active metal sintered membrane reactor anchored with Pt atoms
Ren, Xiaoliang,Wang, Shufang,Ding, Xiaoshu,Zhang, Dongsheng,Wang, Yanji
, p. 2848 - 2853 (2021)
In the chemical industry, reactors are typically designed and filled with supported catalyst particles. However, the intrinsic problems associated with the internal/external diffusion effect and catalyst separation/loss in these traditional reactors can be very challenging to mitigate. To address these issues, herein, an active metal sintered membrane reactor anchored with Pt atoms was successfully developed, and applied into continuous, liquid-phase, hydrogenation processes. The catalyzing reactions transpired on the active sites that were fastened onto the surface of the reactor's microchannels. As a result, the mass transfer at the gas-liquid-solid three-phase was greatly enhanced, and an incredibly high reaction efficiency was obtained. The novel, active reactor demonstrated a superior catalytic performance and stability to nitrobenzene (NB) hydrogenation at 120 °C and 0.5 MPa H2, which enabled an aniline (ANI) yield of 19.28 molANI h-1 L-1. This work opens a new window for the design of high-performance gas-liquid-solid reactor toward multiphase catalytic reactions. This journal is
Highly Selective Room Temperature Monoreduction of Dinitro-arenes by Hydrogen Sulfide under Liquid–Liquid Biphasic Catalysis
Mondal, Ujjal,Sen, Sujit
, p. 15 - 30 (2018)
Selective reduction of one of the nitro group present in dinitro aromatic compounds by a novel Zinin reagent, H2S-laden N-methyldiethanolamine (MDEA) solution, has been explored in the presence of tetra-n-butyl phosphonium bromide as a phase transfer catalyst under the liquid–liquid mode of reaction. Under the room temperature reaction condition, reduction of 2,4-dinitrotoluene (2,4-DNT) with H2S-laden MDEA leads to the selective reduction of one nitro group present either at the fourth position to obtain 4-amino-2-nitrotoluene (4A2NT) or at the second position to get 2-amino-4-nitrotoluene (2A4NT). The reaction was very fast to achieve 100% conversion, and the selectivity of 4A2NT is much higher than the 2A4NT. A detailed parametric study was performed to analyze the effect of parameters on 2,4-DNT conversion and selectivity of both the isomers. The apparent activation energy was found to be as high as 46.25 kJ/mol, and the reaction was found to be kinetically controlled. An empirical kinetic model has been developed to correlate with the conversion version time data obtained experimentally. The present system dealt with an industrial problem in dealing with H2S, present in by-product gaseous streams of many petroleum and natural gas industries. Novelties in the selective monoreduction lie in that fact that the reaction was done at room temperature (303 K), with a novel reagent, H2S-laden MDEA solution. Therefore waste-minimization was effected to yield value-added fine chemicals, that is, amines.
Altering the regioselectivity of a nitroreductase in the synthesis of arylhydroxylamines by structure-based engineering
Bai, Jing,Zhou, Yong,Chen, Qi,Yang, Qing,Yang, Jun
, p. 1219 - 1225 (2015)
Nitroreductases have great potential for the highly efficient reduction of aryl nitro compounds to arylhydroxylamines. However, regioselective reduction of the desired nitro group in polynitroarenes is still a challenge. Here, we describe the structure-based engineering of Escherichia coli nitroreductase NfsB to alter its regioselectivity, in order to achieve reduction of a target nitro group. When 2,4-dinitrotoluene was used as the substrate, the wild-type enzyme regioselectively reduced the 4-NO2 group, but the T41L/N71S/F124W mutant primarily reduced the 2-NO2 group, without loss of activity. The crystal structure of T41L/N71S/F124W and docking experiments indicated that the regioselectivity change (from 4-NO2 to 2-NO2) might result from the increased hydrophobicity of residues 41 and 124 (proximal to FMN) and conformational changes in residues 70 and 124. The regioselectivity of nitroreductase NfsB from E. coli toward 2,4-dinitrotoluene was shifted from the 4-NO2 group to the 2-NO2 group without loss of activity, by introducing three mutations: T41L, N71S, and F124W. This study provides an example of a tailored enzyme for regioselective synthesis of the target arylhydroxylamines.
Catalytic transfer hydrogenation of nitro and carbonyl compounds over novel Fe(III) substituted hexagonal mesoporous aluminophosphates
Sonavane, Sachin U.,Mohapatra, Susanta K.,Jayaram, Radha V.,Selvam, Parasuraman
, p. 142 - 143 (2003)
Catalytic transfer hydrogenation (CTH) of aromatic nitro and carbonyl compounds over novel Fe(III) substituted hexagonal mesoporous aluminophosphate (FeHMA) molecular sieve catalyst showed excellent regioselectivity/chemoselectivity as well as superior recycling capability. Furthermore, the reduction occurs without affecting other functional groups such as -CN, -CHO, -Cl,-CH3,-OCH3 and -NH2.
Reactivity of metal-containing monomers 66.* Hydrogenation of nitrotoluene derivatives in the presence of polymer-immobilized Pd nanoparticles
Dzhardimalieva,Dorokhov,Golubeva,Pomogailo,Lyakhovich,Savchenko,Pomogailo
, p. 2070 - 2076 (2009)
A new approach to the synthesis of immobilized catalysts of the mixed type was developed: frontal polymerization of metal-containing monomers in the presence of a highly dispersed inorganic support. The synthesis of the acrylamide complex of PdII nitrate on the SiO2 surface followed by polymerization and reduction results in the formation of a polymer-inorganic composite with inclusions of Pd nanoparticles stabilized by the polymer matrix on the support surface. The study of the catalytic properties in the hydrogenation of nitrotoluene derivatives showed that the polymer-immobilized Pd nanoparticles on the inorganic support are efficient catalysts for the reduction of the nitrocompounds.
Electrochemical treatment of 2,4,6-trinitrotoluene and related compounds
Rodgers, James D.,Bunce, Nigel J.
, p. 406 - 410 (2001)
This work involves electrolysis of nitrotoluene congeners, which are persistent pollutants that enter the environment as a consequence of their manufacture and use as explosives. Reduction to aminotoluenes occurred with high current efficiency at a variety of cathodes, at potentials -0.5 to -1 V vs SCE. The products were formed in high chemical yield and with excellent mass balance. Preliminary experiments were also carried out to find methods of removing the electrolysis products from solution by oxidative oligomerization. The most satisfactory method was partial reoxidation at a Ti/IrO2 anode, suggesting an overall remediation technology in which reduction is followed by reoxidation of the spent catholyte in the anode compartment of the same electrolytic cell. This work involves electrolysis of nitrotoluene congeners, which are persistent pollutants that enter the environment as a consequence of their manufacture and use as explosives. Reduction to aminotoluenes occurred with high current efficiency at a variety of cathodes, at potentials -0.5 to -1 V vs SCE. The products were formed in high chemical yield and with excellent mass balance. Preliminary experiments were also carried out to find methods of removing the electrolysis products from solution by oxidative oligomerization. The most satisfactory method was partial reoxidation at a Ti/IrO2 anode, suggesting an overall remediation technology in which reduction is followed by reoxidation of the spent catholyte in the anode compartment of the same electrolytic cell.
DNA interaction of bromomethyl-substituted acridines
Harada, Kazuya,Imai, Takahiro,Kizu, Junko,Mochizuki, Masataka,Inami, Keiko
, p. 3375 - 3383 (2017/10/07)
A series of acridines with bifunctional substituents was synthesized with the dual properties of DNA alkylation and intercalation. 4,5-Bis(bromomethyl)acridine (1) was previously reported to crosslink and intercalate with DNA. In this study, 1,8-bis(bromomethyl)acridine (2) and 2,7-bis(bromomethyl)acridine (3), monofunctional 2-(bromomethyl)-7-methylacridine (4) and 2,7-dimethylacridine (5) were synthesized, and their crosslinking and intercalative activities were investigated to assess the reactivity of bromomethyl acridines with DNA. Interstrand crosslinking activity was similar among the three bis(bromomethyl)acridines. The acridines exhibited intercalation activity for calf thymus DNA as follows: 3 > 4 > 2 = 1 5. Intracellular DNA-crosslinking and DNA-intercalating activities were evaluated using the Ames assay. 4 was mutagenic in Salmonella typhimurium TA100 and TA98, indicating that the bromomethyl group alkylated DNA bases. All three bis(bromomethyl)acridines were mutagenic in S. typhimurium TA92 and TA94, which can detect intracellular crosslinking DNA damage, whereas 5 was not mutagenic in these strains. The results showed that the bis(bromomethyl)acridines crosslinked DNA and intercalated between DNA bases, and 3 exhibited the highest crosslinking and intercalating activity.
Gold supported on titania for specific monohydrogenation of dinitroaromatics in the liquid phase
Liu, Shuang-Shuang,Liu, Xiang,Yu, Lei,Liu, Yong-Mei,He, He-Yong,Cao, Yong
, p. 4162 - 4169 (2014/09/29)
Liquid-phase selective monohydrogenation of various substituted dinitroaromatics to the corresponding valuable nitroanilines was investigated on gold-based catalysts. Special attention was paid to the effect of Au particle size on this monoreduction reaction. Interestingly, TiO2 supported gold catalysts containing a relatively larger mean Au particle size (>5 nm) showed far superior chemoselectivity for specific mono-hydrogenation of dinitroaromatics, with the highest performance attainable for the catalyst bearing Au particles of ca. 7.5 nm. Results in the intermolecular competitive hydrogenation showed that the intrinsic higher accumulation rates of the desired nitroanilines associated with the catalyst possessing larger Au particles were responsible for the high chemoselectivity observed. the Partner Organisations 2014.
SUBSTITUTED AROMATIC CARBOXAMIDE AND UREA DERIVATIVES AS VANILLOID RECEPTOR LIGANDS
-
Page/Page column 121, (2010/11/18)
The invention relates to substituted aromatic carboxamide and urea derivatives, to processes for the preparation thereof, to pharmaceutical compositions containing these compounds and also to the use of these compounds for preparing pharmaceutical compositions (formula (I)).
