100-25-4Relevant articles and documents
Highly efficient dinitration of aromatic compounds in fluorous media using ytterbium perfluorooctanesulfonate and perfluorooctanesulfonic acid as catalysts
Yi, Wen-Bin,Cai, Chun
, p. 2957 - 2961 (2006)
Ytterbium perfluorooctanesulfonate [Yb(OPf)3] and perfluorooctanesulfonic acid [PfOH] catalyze the highly efficient dinitration of toluene, benzene, benzyl chloride, and chlorobenzene in fluorous media. Notably the process produces almost no waste acid, as opposed to the traditional case. The fluorous phase-containing catalyst could be easily and efficiently recovered for reuse by simple phase separation. Copyright Taylor & Francis Group, LLC.
Photochemical generation of radical cations of dithienothiophenes, condensed thiophene trimers, studied by laser flash photolysis
Fujitsuka, Mamoru,Sato, Tadatake,Shimidzu, Takeo,Watanabe, Akira,Ito, Osamu
, p. 1056 - 1061 (1997)
Photoinduced electron-transfer reactions between dithienothiophene (DTT) and the electron acceptors, p-dinitrobenzene (DNB) and CCl4, have been investigated using nanosecond laser flash photolysis and time-resolved fluoresence spectroscopy. Generation of the radical cations of DTTs and radical anion of DNB in acetonitrile solution was confirmed by transient absorption spectra in the visible and near-IR regions. Observed transient absorption bands corresponded to those of radical ions generated by γ irradiation in a frozen matrix. Electron transfer occurred both from the singlet and triplet excited states of DTT to DNB at the diffusion-controlled rate, ～1010 M-1 s-1. When CCl4 was used as an acceptor, electron transfer from the singlet excited state occurred at the diffusion-controlled rate, while the reaction from the triplet excited state occurred at 9 M-1 s-1 due to small ΔG0 for this reaction. For both acceptors, the singlet route tended to dominate the triplet route when concentration of the acceptor was increased. The radical ions decayed with second-order kinetics by back-electron transfer at a rate closed to the diffusion-controlled limit. In cyclohexane, generation of radical ions was completely suppressed and the triplet excited state of DTT was deactivated by energy transfer to DNB.
NITRATION OF AROMATIC COMPOUNDS CATALYZED BY ZrO2/SO42-
Nagi, Sh. M.,Zubkov, E. A.,Shubin, V. G.
, p. 1500 - 1502 (1990)
Catalytic activity was demonstrated for zirconium dioxide, which is a solid acid, modified by sulfate ions in the nitration of inactive aromatic compounds.
Solvent Effects in the Nitration of Nitrobenzene
Fujiwara, Kenji,Andoh, Takayuki,Arai, Mitsuru,Tamura, Masamitsu,Yoshida, Tadao
, p. 4973 - 4976 (1980)
Results obtained from nitration of nitrobenzene and methyl phenyl sulfone with nitronium hexafluorophosphate in nitromethane gave a good Hammett relationship using ?+ as the substituent constant (ρ=-8.5,n=11,r=0.99), in contrast to the results
Ipso Nitration of Aryl Boronic Acids Using Fuming Nitric Acid
Baucom, Kyle D.,Brown, Derek B.,Caille, Seb,Murray, James I.,Quasdorf, Kyle,Silva Elipe, Maria V.
, (2021)
The ipso nitration of aryl boronic acid derivatives has been developed using fuming nitric acid as the nitrating agent. This facile procedure provides efficient and chemoselective access to a variety of aromatic nitro compounds. While several activating agents and nitro sources have been reported in the literature for this synthetically useful transformation, this report demonstrates that these processes likely generate a common active reagent, anhydrous HNO3. Kinetic and mechanistic studies have revealed that the reaction order in HNO3 is >2 and indicate that the ?NO2 radical is the active species.
Intervalence near-IR spectra of delocalized dinitroaromatic radical anions
Nelsen, Stephen F.,Konradsson, Asgeir E.,Weaver, Michael N.,Telo, Joao P.
, p. 12493 - 12501 (2003)
The Class III (delocalized) intervalence radical anions of 1,4-dinitrobenzene, 2,6-dinitronaphthalene, 2,6-dinitroanthracene, 9,9-dimethyl-2,7-dinitrofluorene, 4,4′-dinitrobiphenyl, and 1,5-dinitronaphthalene show charge-transfer bands in their near-IR spectra. The dinitroaromatic radical anions have comparable but slightly larger electronic interactions (Hab values) through the same aromatic bridges as do the corresponding dianisylamino-substituted radical cations. Hab values range from 5410 cm-1 (1,4-dinitrobenzene) to 3400 cm -1 (9,9-dimethyl-2,7-dinitrofluorene), decreasing as the number of bonds between the nitro groups increases, except for the 1,5-dinitronaphthalene radical-anion, which has a coupling similar to that of 9,9-dimethyl-2,7-dinitrofluorene. All charge-transfer bands show vibrational fine structure. The vertical excitation energies (λv) were estimated from the vibrational components, obtained by simulation of the entire band. The large 2Hab/λv values confirm these radicals to be Class III delocalized mixed-valence species. Analysis using Cave and Newton's generalized Mulliken-Hush theory relating the transition dipole moment to the distance on the diabatic surfaces suggests that the electron-transfer distance on the diabatic surfaces, dab, is only 26-40% of the nitrogen-to-nitrogen distance, which implies that something may be wrong with our analysis.
Solvent effects on intramolecular electron exchange in the 1,4- dinitrobenzene radical anion
Telo,Grampp,Shohoji
, p. 99 - 104 (1999)
The rate constants of the intramolecular electron exchange reaction in the 1,4-dinitrobenzene radical anion in linear alcohols were determined from alternating line-broadening effects in EPR spectra. Rate constants at 293 K range from 2.9 x 109 s-1 in methanol to 2.7 x 108 s-1 in octan-1-ol. The rate constant was found to depend on the reverse of the longitudinal correlation time of the solvent, τ(L), as expected for a solvent-controlled adiabatic reaction. Applying Marcus theory and the ellipsoidal cavity model for evaluating λ0, the amount of transferred charge between nitro groups, z, and the outer-sphere reorganisation energy were determined, z changes from 0.56 at 273 K to 0.52 at 313 K. λ0 at 293 K changes from 61 kJ mol-1 in octan-1-ol to 80 kJ mol-1 in methanol. The activation energies were obtained from the temperature dependence of the rate constants, changing from 26 kJ mol-1 in methanol to 36 kJ mol-1 in octan-1-ol. The variation of this energy clearly reflects the increase in the exponential term of τ(L) for the more viscous alcohols. The results for the 1,4-dinitrobenzene radical anion were compared with those previously reported for the radical anion of 1,3-dinitrobenzene. Rate constants are smaller in the former, by three orders of magnitude, due to conjugation of the nitro groups.
Energy transfer, electron transfer, and addition reactions of triplet state of 1,3-dihydroimidazole-2-thiones investigated by laser flash photolysis
Alam, Maksudul M.,Ito, Osamu
, p. 339 - 345 (1999)
The transient absorption bands observed at ca. 400 and 550 nm for 1,3- dihydro-2H-imidazole-2-thione (IT), 1,3-dihydro-1-methyl-2H-imidazole-2- thione (MIT), and 1,3-dihydro-2H-benzimidazole-2-thione (BIT) have been assigned to their triplet states (3IT* 's) by the quenching and sensitizing experiments using laser flash photolysis technique. Short intrinsic triplet lifetimes and relatively high triplet energies have been evaluated as characteristics of 3IT* 's. For electron acceptors, photoinduced electron- transfer reaction occurs via 3IT* 's in the diffusion controlled limit. The nucleophilic character of 3IT* 's was confirmed by changing the substituents of alkenes on the addition reactions. MO calculations indicate that the lowest electronic configurations of both 3IT* and 3MIT* have 3(n,π*) character, while 3BIT* has 3(π,π*) character. The addition reactivity of 3BIT* is slightly higher than those of 3IT* and 3MIT*, which is opposite to the general tendency.
Enhancing the photocatalytic activity of GaN by electrochemical etching
Cao, Dezhong,Xiao, Hongdi,Xu, Hangzhou,Cui, Jishi,Gao, Qingxue,Pei, Haiyan
, p. 881 - 886 (2015)
Nanoporous (NP) GaN thin films prepared with electrochemical etching method were investigated as photocatalysts in dye photodegradation systematically. The comparison of NP GaN thin films with GaN thin films showed that NP GaN thin films with high surface
Nitration of deactivated aromatic compounds via mechanochemical reaction
Wu, Jian-Wei,Zhang, Pu,Guo, Zhi-Xin
supporting information, (2021/05/05)
A variety of deactivated arenes were nitrated to their corresponding nitro derivatives in excellent yields under high-speed ball milling condition using Fe(NO3)3·9H2O/P2O5 as nitrating reagent. A radical involved mechanism was proposed for this facial, eco-friendly, safe, and effective nitration reaction.
