T:Toxic;581-89-5Relevant articles and documents
Lanthanide(III) nitrobenzenesulfonates as new nitration catalysts: The role of the metal and of the counterion in the catalytic efficiency
Parac-Vogt, Tatjana N.,Pachini, Sophia,Nockemann, Peter,Van Hecke, Kristof,Van Meervelt, Luc,Binnemans, Koen
, p. 4560 - 4566 (2004)
Lanthanide(III) complexes of p-nitrobenzenesulfonic acid, Ln(p-NBSA) 3, m-nitrobenzenesulfonic acid, Ln(m-NBSA)3, and 2,4-nitrobenzenesulfonic acid, Ln(2,4-NBSA)3, were prepared, characterized and examined as catalyst for the nitration of benzene, toluene, xylenes, naphthalene, bromobenzene and chlorobenzene. The initial screening of the catalysts showed that lanthanum(III) complexes were more effective than the corresponding ytterbium(III) complexes, and that catalysts containing the bulky 2,4-NBSA ligand were less effective than the catalyst containing p-NBSA (nosylate) or m-NBSA ligands. Examination of a series of Ln(p-NBSA)3 and Ln(m-NBSA)3 catalysts revealed that there is a clear correlation between the ionic radii of the lanthanide(III) ions and the yields of nitration, with the lighter lanthanides being more effective. The X-ray single crystal structure of Yb(m-NBSA)3·6H2O shows that two m-NBSA ligands are directly bound to the metal centre while the third ligand is not located in the first coordination sphere, but it is hydrogen bonded to one of the water molecules which is coordinated to ytterbium(III). NMR studies suggest that this structure is preserved under the conditions used in the nitration reaction. The structure of Yb(m-NBSA)3 is markedly different from the structure of the well-known ytterbium(III) triflate catalyst. The coordination of the nitrobenzenesulfonate counterion to the lanthanide(III) ion suggests that steric effects might play an important role in determining the efficiency of these novel nitration catalysts. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
Competitive Reactions of Trinitromethanide Ion and Nitrogen Dioxide with Radical Cations
Eberson, Lennart,Hartshorn, Michael P.,Svensson, Jan O.
, p. 1614 - 1615 (1993)
From the species generated by photoexcitation of ArH-tetranitromethane charge transfer complexes, ArH radical cation, trinitromethanide ion and nitrogen dioxide, the reaction between ArH radical cation and trinitromethanide has been shown to be significantly faster than that between ArH radical cation and nitrogen dioxide.
Zeolite-assisted regioselective synthesis of dinitronaphthalene
Wang, Haocai,Peng, Xinhua,Shi, Chunjie,Dong, Xiongzi,Tai, Yanfang,Liu, Hongtao
, p. 1495 - 1500 (2014)
The nitration selectivity of naphthalene was studied in different organic solvents with 95 % fuming nitric acid as nitration reagent. The yield of dinitronaphthalene can achieve 78 % in hexane. With nitrogen dioxide as nitration reagent in oxygen, the selectivity of dinitronaphthalene in different types of molecular sieve catalyst was studied. When HBEA zeolite catalyst was used, the yield of dinitronaphthalene was up to 61 %. This method is easy to carry out, environmentally benign, and economical.
NO2+ nitration mechanism of aromatic compounds: Electrophilic vs charge-transfer process
Tanaka, Mutsuo,Muro, Eiko,Ando, Hisanori,Xu, Qiang,Fujiwara, Masahiro,Souma, Yoshie,Yamaguchi, Yoichi
, p. 2972 - 2978 (2000)
The nitration of methylnaphthalenes with NO2BF4 and NOBF4 was examined in order to shed light on the controversial aromatic nitration mechanism, electrophilic vs charge-transfer process. The NO2+ nitration of 1,8-dimethylnaphthalene showed a drastic regioselectivity change depending on the reaction temperature, where ortho-regioselectivity at -78 °C and para- regioselectivity at 0 °C were considered to reflect the electrophilic and the direct or alternative charge-transfer process, respectively, because the NO+ nitration through the same reaction intermediates as in the NO2+ nitration via a charge-transfer process resulted in para-regioselectivity regardless of the reaction temperature. The NO2+ nitration of redox potential methylnaphthalenes higher than 1,8-dimethylnaphthalene gave a similar ortho-regioselectivity enhancement to 1,8-dimethylnaphthalene at lower temperature, thus reflecting the electrophilic process. On the other hand, the NO2+ nitration of redox potential methylnaphthalenes lower than 1,8-dimethylnaphthalene showed para-regioselectivity similar to the NO+ nitration, indicating the direct or alternative charge-transfer process. In the presence of strong acids where the direct charge-transfer process will be suppressed by protonation, the ortho-regioselectivity enhancement was observed in the NO2+ nitration of 1,8-dimethylnaphthalene, suggesting that the direct charge-transfer process could be the main process to show para- regioselectivity. These experimental results imply that the NO2+ nitration proceeds via not only electrophilic but also direct charge-transfer processes, which has been considered to be unlikely because of the high energy demanding process of a bond coordination change between NO2+ and NO2. Theoretical studies at the MP2/6-31G(d) level predicted ortho- and para-regioselectivity for the NO2+ nitration via electrophilic and charge- transfer processes, respectively, and the preference of the direct charge- transfer process over the alternative one, which support the experimental conclusion.
Photochemical Nitration by Tetranitromethane. Part XIX. The Competitive Reactions of Trinitromethanide and Nitrogen Dioxide with Radical Cations and their Use for Selective Nitrations
Eberson, Lennart,Hartshorn, Michael P.,Radner, Finn,Svensson, Jan O.
, p. 1719 - 1730 (1994)
The photolysis of the charge-transfer complex between an aromatic compound (ArH) and tetranitromethane is known to form initially a triad of the aromatic radical cation, trinitromethanide ion and NO2 .For reactive and moderately reactive radical cations, the chemical follow-up ion and (i) reactions from the species of the triad are fast at -60 deg C, as shown by the fact that the solutions are EPR-silent during photolysis.However, by conducting the photolysis in the presence of a protic acid, the trinitromethanide ion is rendered unreactive by protonation, resulting in the build-up of a detectable (EPR) concentration of ArH-radical cation or (ArH)2-radical cation.This shows that the initial chemical step from the triad is the nucleophilic attack of trinitromethanide ion upon ArH-radical cation, and that the rate of the reaction between the latter and NO2 must be significantly lower.Preparative experiments support this conclusion, in that the predominant adduct formation from ArH-tetranitromethane photolysis is diverted into nitro substitution in the presence of a protic acid, the latter reaction occurring via ArH-radical cation-NO2 coupling.These findings also establish that results obtained from the photonitration of aromatics by tetranitromethane are not relevant for judging the possible electron transfer nature of electrophilic aromatic nitration by nitronium ion.
Photoinduced Iron-Catalyzed ipso-Nitration of Aryl Halides via Single-Electron Transfer
Wu, Cunluo,Bian, Qilong,Ding, Tao,Tang, Mingming,Zhang, Wenkai,Xu, Yuanqing,Liu, Baoying,Xu, Hao,Li, Hai-Bei,Fu, Hua
, p. 9561 - 9568 (2021/08/06)
A photoinduced iron-catalyzed ipso-nitration of aryl halides with KNO2 has been developed, in which aryl iodides, bromides, and some of aryl chlorides are feasible. The mechanism investigations show that the in situ formed iron complex by FeSO4, KNO2, and 1,10-phenanthroline acts as the light-harvesting photocatalyst with a longer lifetime of the excited state, and the reaction undergoes a photoinduced single-electron transfer (SET) process. This work represents an example for the photoinduced iron-catalyzed Ullmann-type couplings.
Bismuth nitrate as a source of nitro radical in ipso-nitration of carboxylic acids
Agasti, Soumitra,Maiti, Siddhartha,Maity, Soham,Anniyappan,Talawar,Maiti, Debabrata
, p. 120 - 124 (2019/05/22)
Aromatic nitro compounds are extensively used in synthetic chemistry. We disclose a new approach to obtain nitroarenes regioselectively starting from carboxylic acids under acid-free reaction conditions.
