1227476-15-4

Basic information

• Product Name: Azobenzene
• Synonyms: Azobenzene
• CAS NO: 1227476-15-4
• Molecular Weight: 182.225
• Mol File: 1227476-15-4.mol
• Article Data: 441

Chemical Properties

• CAS DataBase Reference: Azobenzene(CAS DataBase Reference)
• NIST Chemistry Reference: Azobenzene(1227476-15-4)
• EPA Substance Registry System: Azobenzene(1227476-15-4)

Safety Data

• Hazardous Substances Data: 1227476-15-4(Hazardous Substances Data)

Upstream product

• 186581-53-3 diazomethane 
• 60-29-7 diethyl ether 
• 148-97-0 N-hydroxy-N-nitroso-benzenamine 
• 110-86-1 pyridine 
• 124-41-4 sodium methylate 
• 98-95-3 nitrobenzene 
• 20972-43-4 trans-azoxybenzene 
• 56-23-5 tetrachloromethane 
• 606-88-2 N,N,N'-triphenylhydrazine 
• 861569-58-6 N'-phenyl-N,N-di-p-tolyl-hydrazine 
• 61066-33-9 pyrimidine-2,4,5,6(1H,3H)-tetraone 
• 64-17-5 ethanol 
• 122-66-7 diphenyl hydrazine 
• 117070-63-0 4-phenylazo-benzenediazonium; hydroxide 

Downstream Products

• 28346-30-7 bis-(3-nitro-benzylidene)-benzidine 
• 3460-11-5 4-nitrobenzanilide 
• 28346-31-8 N⁴,N^4'-bis(4-nitrobenzylidene)[1,1'-biphenyl]-4,4'-diamine 
• 6311-48-4 N,N'-dibenzylidene-benzidine 
• 93-98-1 N-phenyl benzoyl amide 
• 970-26-3 N,N'-diphenylbenzohydrazide 
• 35787-09-8 1,2-dibenzoyl-1,2-diphenylhydrazine 
• 606-88-2 N,N,N'-triphenylhydrazine 
• 6327-79-3 1-(4-methoxyphenyl)-3-phenylpropane-1,3-dione 
• 539-03-7 N-(4-chlorophenyl)acetamide 
• 1602-00-2 bis-(4-chloro-phenyl)-diazene 
• 4935-82-4 2,3,7,8-tetraanilino-5-phenyl-phenazinium; chloride 
• 103-19-5 di(p-tolyl) disulfide 
• 18826-19-2 octaphenyl-[1,2,4,5,3,6]tetraazadisilinane 

Relevant articles and documents

Ethylenediamine promoted the hydrogenative coupling of nitroarenes over Ni/C catalyst

Azobenzene and its derivatives are key raw materials and it is an environmentally friendly method for the preparation of azobenzene by hydrogenative coupling of nitrobenzene. The development of nickel based catalyst for organic transformations is of importance because of its relatively low cost and toxicity. In this work, we found that ethylenediamine can enrich the electron state of Ni and make the azobenzene easily desorb from the surface of the catalyst, which inhibits the hydrogenation of azobenzene to aniline. The selectivity of azobenzene is greatly improved. When the ratio of Ni and ethylenediamine is 1:10, the yield of the azobenzene can reach 95.5%.

A NOVEL REACTION OF ACETANILIDE WITH NITROBENZENE IN DMSO - AN UNUSUAL SOLVENT ASSISTED REGIOSELECTIVE AROMATIC NUCLEOPHILIC SUBSTITUTION

The reaction of acetanilide (1) with nitrobenzene (2) in the presence of a base in DMSO yielded p-nitrosodiphenylamine (3) as the major product.This unusual regioselective formation of the deoxygenated product 3 has been rationalized in terms of solvent effects exerted by DMSO.

A new preparative method, characterization, and reactivity of disulphide dication salts of cyclic bis-sulphides: R2S-SR2· 2CF3SO3-

The reaction of 1,5-dithiacyclo-octane 1-oxide with trifluoromethanesulphonic anhydride affords the corresponding disulphide dication as a stable crystalline salt which serves as an oxidizing agent in the oxidation of 1,2-diphenylhydrazine; the disulphide dication of 1,4-dithiane has also been isolated.

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Di- and Trinuclear Iridium(III) Complexes with Poly-Mesoionic Carbenes Synthesized through Selective Base-Dependent Metalation

Mutidentate carbene ligands based on a rigid aromatic platform are valuable synthons for generating carbene complexes with higher nuclearity. We present here the selective, base-dependent synthesis of a dinuclear or a trinuclear IrIII complex from the 1,3,5-substituted benzene derived tris-triazolium salt. The dinuclear IrIII complex features an unreacted triazolium unit which enables us to compare the metric parameters between the bonded 1,2,3-triazol-5-ylidene to their parent triazolium salt present in the same molecule. Single crystal X-ray diffraction studies confirm the di- and trinuclear nature of the complexes and establish their configuration and conformation. Both the di- and trinuclear IrIII complexes have been used for catalytic transfer hydrogenation, and these complexes are potent precatalysts delivering good to excellent yields for the reduction of benzaldehyde, acetophenone, benzophenone, and cyclohexanone. Furthermore, they show a preference for reducing nitrobenzene to either azoxybenzene or azobenzene. Mercury poisoning tests conclusively prove the homogeneous nature of the reported catalysis. The lack of orthometalation in these complexes and the possible effect thereof on catalysis are discussed. (Chemical Equation Presented).

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1D coordination polymer based on copper(II)-containing tetrameric 1,2,3-triazole ligand from click chemistry: Magnetic and catalytic properties

A novel tetrameric tetra[O-((1-benzyl-1H-1,2,3-triazol-4-yl)methyl)]-pentaerythritol (TBTP) has been synthesized using click chemistry strategy. TBTP was characterized and used as ligand to form new Cu(II) complexes, forming 1-D coordination polymers. Two square planar complexes were characterized by single-crystal X-ray diffraction, presenting formula [Cu(TBTP)][Cu(NO3)4] (1) and [Cu(TBTP)](NO3)2 (2). In both structures, a cationic 1-D coordination polymer (CP) has been formed. The CP contain a 1:1 Cu(II)/TBTP ratio with four neutral triazole groups coordinating the Cu(II) center, forming a Cu[sbnd]N bonds ranging 1.988(2)–2.001(2) ?. The study of the magnetic properties of compounds 1 and 2 pointed to an antiferromagnetic behavior for both compounds, defined by inter- and intra-chain dipolar interactions among their metallic centers. In addition, the complex 1 was found to be an efficient catalyst for selective oxidation of aniline to azobenzene under mild reaction conditions.

Room temperature selective reduction of nitroarenes to azoxy compounds over Ni-TiO2 catalyst

Surface tuned Ni-TiO2 catalyst was prepared by hydro-solvothermal method using poly(diallyldimethylammonium chloride) (or PDADMAC) as a surfactant and hydrazine hydrate as a capping agent. Activity of catalyst was investigated for selective reduction of nitrobenzene to azoxybenzene in aqueous medium at room temperature, using hydrazine hydrate as the reducing agent for catalysis. It was observed that the catalyst prepared by hydro-solvothermal method (2.6 % Ni-TiO2EG?W?H) showed 92 % selectivity of azoxybenzene with 89 % conversion of nitrobenzene, under mild reaction conditions, which is quite higher as compared to reported non-noble metal catalysts. Prepared catalysts were thoroughly characterized by various analytical techniques to find out the physicochemical characteristic features of the materials. 2.6 % Ni-TiO2EG-W catalyst exhibited highly dispersed nickel nanoparticles (～6.8 nm) over TiO2 surface and strong metal-support interaction due to smaller size of Ni-particles, which significantly enhanced the catalytic efficiency towards selective reduction of nitroarenes to azoxy compounds. Effect of solvents on catalyst synthesis process was also investigated and reported for establishing the superiority of 2.6 % Ni-TiO2EG-W catalyst. The heterogeneous nature of highly dispersed catalyst (2.6 % Ni-TiO2EG-W) was confirmed by the recyclability tests and found that the catalyst particles can be easily recovered and recycled up to four successive runs without any significant loss in its catalytic performance.

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Correction to "electrochemically Determined O-H Bond Dissociation Free Energies of NiO Electrodes Predict Proton-Coupled Electron Transfer Reactivity" (Journal of the American Chemical Society (2019)141: 38 (14971-14975)Doi: 10.1021/jacs.9b07923)

The aqueous CG value used to calculate the bond dissociation free energy (BDFE) values reported in the published Communication was incorrect due to a sign error in its derivation. This systematic error does not affect the conclusions of the study, as all of the aqueous BDFE values shift together. The correct aqueous CG,H2O value is 52.8 kcal mol?1, as reported by Connelly, Wiedner, and Appel.1 We thank Drs. Wiedner and Appel for helpful discussions regarding this correction. We report here revised equations, tables, and schemes with BDFE values adjusted for the correct aqueous CG,H2O term. Pages 14971 and 14972. Equation 1 has been modified to report the correct aqueous CG term, and eqs 4 and 5, which give BDFE values for NiII(OH)2 and NiIIIO(OH), have also been adjusted accordingly. The revised equations are shown below: BDFE(X?H) = 23.06E(pH 0) + 52.8 kcal mol?1 (1) = } =} ? ? Ni O(OH)/Ni (OH) E 0.99 0.03 V BDFE 75.6 1.0 kcal mol III II 2 1 (4) = } = } ? ? Ni O /Ni O(OH) E 1.36 0.02 V BDFE 84.2 1.0 kcal mol IV 2 III 1 (5) Revised BDFE values for the PCET substrates discussed in the original text are given in Table 1. Page 14973. The BDFE ranges discussed in the original publication were adjusted in a similar manner. Thermodynamically favorable reactions at NiIIIO(OH) are predicted for substrates with X?H BDFE less than 75 kcal mol?1 (and were observed for substrates with X?H BDFE ranging from 61 to 73 kcal mol?1). Thermodynamically unfavorable reactivity is predicted (and was observed) for substrates with X?H BDFE greater than 76 kcal mol?1. The observed equilibrium reactivity with 2,4,6-tBu3PhOH is consistent with both the substrate and NiII(OH)2 having an O?H BDFE of ?75.5 kcal mol?1. The number line in Scheme 1 has been adjusted to reflect the corrected BDFE values, and the revised scheme is shown below. [Formula presented] Supporting Information. The BDFE values reported in Tables S1 and S5 were also adjusted for the correct aqueous CG value. The corrected tables are provided in the complete, revised Supporting Information file.

Chitosan-derived N-doped carbon catalysts with a metallic core for the oxidative dehydrogenation of NH-NH bonds

Sustainable metal-encased (Ni-Co/Fe/Cu)?N-doped-C catalysts were prepared from bio-waste and used for the oxidative dehydrogenation reaction. A unique combination of bimetals, in situ N doping, and porous carbon surfaces resulted in the formation of the effective "three-in-one" catalysts. These N-doped graphene-like carbon shells with bimetals were synthesized via the complexation of metal salts with chitosan and the subsequent pyrolysis at 700 °C. A well-developed thin-layer structure with large lateral dimensions could be obtained by using Ni-Fe as the precursor. Importantly, the Ni-Fe?N-doped-C catalyst was found to be superior for the dehydrogenation of hydrazobenzene under additive/oxidant-free conditions compared to the conventional and other synthesized catalysts. Characterizations by TEM and XPS accompanied by BET analysis revealed that the enhanced catalytic properties of the catalysts arose from their bimetals and could be attributed to the graphitic shell structure and graphitic N species, respectively.

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Electron-excited dioxygen generated by the tri-tert-butoxyaluminum - tert-butyl hydroperoxide system as an efficient oxidant of aniline and some N-substituted anilines

The tri-tert-butoxyaluminum - tert-butyl hydroperoxide system generates molecular oxygen in the electron-excited singlet state (1O 2), which oxidizes diphenylamine, N-ethylaniline, aniline, and 2,6-diisopropylaniline to form nitroxyl radicals. The latters were identified by ESR at 240-293 K. Oxidation proceeds via the intermediate formation of nitrogen-containing N-peroxide compounds.

PHOTOLYSIS OF PHENYL AZIDE

The quantum yield for the photodissociation of phenyl azide in the concentration range from 10-4 to 10-1 M is 0.4-0.5, while the yield of azobenzene does not exceed 50percent. Keywords: phenyl azide, quantum yield, chain decomposition.

Structure and Reactivity of a High-Spin, Nonheme Iron(III)-Superoxo Complex Supported by Phosphinimide Ligands

Nonheme iron oxygenases utilize dioxygen to accomplish challenging chemical oxidations. A further understanding of the Fe-O2 intermediates implicated in these processes is challenged by their highly transient nature. To that end, we have developed a ligand platform featuring phosphinimide donors intended to stabilize oxidized, high-spin iron complexes. O2 exposure of single crystals of a three-coordinate Fe(II) complex of this framework allowed for in crystallo trapping of a terminally bound Fe-O2 complex suitable for XRD characterization. Spectroscopic and computational studies of this species support a high-spin Fe(III) center antiferromagnetically coupled to a superoxide ligand, similar to that proposed for numerous nonheme iron oxygenases. In addition to the apparent stability of this synthetic Fe-O2 complex, its ability to engage in a range of stoichiometric and catalytic oxidation processes demonstrates that this iron-phosphinimide system is primed for development in modeling oxidizing bioinorganic intermediates and green oxidation chemistry.

Quantum Yield Evidence for a Chain Reaction in the Photochemical Decomposition of Phenyl Azide

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A convenient method for dehydrogenation of symmetric hydrazo compounds

A convenient method using FeCl3 as oxidant to dehydrogenate symmetric hydrazo compounds is reported for the first time. The method is superior to other known methods for dehydrogenating ArNHNHAr . It needs only cheap and less toxic reagents, mild conditions and short reaction time. Eight symmetric azo compounds are prepared in good yields.

Tying the alkoxides together: An iron complex of a new chelating bulky bis(alkoxide) demonstrates selectivity for coupling of non-bulky aryl nitrenes

New chelating bis(alkoxide) ligand H2[OO]Ph and its iron(ii) complex Fe[OO]Ph(THF)2 are described. The coordination of the ligand to the metal center is reminiscent of the coordination of two monodentate alkoxides in previously reported Fe(OR)2(THF)2 species. Fe[OO]Ph(THF)2 catalyzes selective and efficient dimerization of non-bulky aryl nitrenes to yield the corresponding azoarenes.

MECHANISM OF REACTION OF AZOBENZENE FORMATION FROM ANILINE AND NITROSOBENZENE IN BASIC CONDITIONS. GENERAL BASE CATALYSIS BY HYDROXIDE ION

The reaction of nitrosobenzene with aniline, to give azobenzene, in basic conditions was studied.It was shown that the reaction exhibits general base catalysis by different buffers giving a Broensted coefficient β = 0.318.As in previous studies, a two-step process with a first step of attack of aniline on nitrosobenzene to give an addition intermediate and a second step of dehydration of this intermediate is proposed to interpret the mechanism of the reaction.The analysis of the Broensted relationship and of the intermediate of the reaction led to the suggestion that hydroxide ion catalyses the reaction by a mechanism of general base catalysis in the dehydration step.

REACTIONS OF SILYL-SUBSTITUTED CARBANIONS WITH NITRONES

The reaction of carbanions, prepared from 2-(trimethylsilylmethyl)pyridine or N,N-dimethyltrimethylsilylacetamide and lithium diisopropylamide in tetrahydrofuran, with α-aryl-N-phenylnitrones afforded a mixture of corresponding (E)-alkene, azobenzene and azoxybenzene, respectively.On the other hand, the carbanions reacted with cyclic nitrones to give the corresponding aziridine and/or hydroxylamine derivatives as major products.

The Reaction of Diazonium Ion Generated from α-Azohydroperoxide with Phenols. The Isolation and Reaction of Diazoether Intermediate

The reaction of benzenediazonium ion generated from α-azohydroperoxide with 1-naphthol gave a diazoether which rearranged to 2- and 4-phenylazo-1-naphthols.

Monodispersed AuPd nanoalloy: Composition control synthesis and catalytic properties in the oxidative dehydrogenative coupling of aniline

A series of AuPd@C nanoalloy catalysts with tunable compositions were successfully prepared by a co-reduction method. The use of borane-tert-butylamine complex as reductant and oleylamine as both solvent and reductant was very effective for the preparation of the monodispersed nanoalloy. We evaluated the catalytic activity of these AuPd@C nanoalloys for oxidative dehydrogenative coupling of aniline, which showed better catalytic activity than equal amounts of sole Au@C or Pd@C catalyst. The Au1Pd3@C catalyst exhibited the best performance, indicating that the conversion and selectivity were improved along with the increase of Pd composition. However if the Pd composition was too high in the AuPd alloy, Au1Pd7@C achieved only 81% conversion in this reaction.

Correlation studies in the oxidation of Vanillin Schiff bases by acid bromate - A kinetic and semi-empirical approach

Kinetics and mechanistic aspects of oxidation of Vanillin Schiff bases (obtained from Vanillin and p-substituted anilines) by bromate in acid medium has been studied at 313 ?K. The reaction exhibited first order in [bromate] and less than unity order each in [Vanillin Schiff base] and [acid]. The increase in the rate of reaction with decrease in dielectric constant of the medium is observed with all the studied substrates. The reaction failed to induce the polymerization of acrylonitrile. Electron withdrawing substituents in the aniline ring moiety of Vanillin Schiff base accelerate the rate of oxidation to a large extent and electron releasing substituents retard the rate. The order of reactivity is found to be p-nitro ?> ?p-bromo ?> ?p-chloro ?> ?–H ?> ?p-fluoro ?> ?p-methyl ?> ?p-methoxy ?> ?p-ethoxy and the sensitivity of the substrates towards the reaction rate is further supported by the semi-empirical calculation of electronic properties and global descriptors of the substrates (Vanillin Schiff bases) with different substituents in the aniline ring moiety. The observed trend in the reactivity of the substrates was correlated with the calculated descriptors like electronegativity, chemical potential, electrophilicity index, chemical hardness and frontier molecular orbitals. The linear free-energy relationship is characterized by a straight line in the Hammett's plot of log k versus σ. The ρ values are positive and increase with increase in temperature. From the Exner and Arrhenius plots, the isokinetic relationship is discussed. Oxidation products identified are p-substituted azobenzene and vanillic acid. Based on the experimental observations, a plausible mechanism is proposed and rate law is derived.

α-Diimine synthesis via titanium-mediated multicomponent diimination of alkynes with C-nitrosos

α-Diimines are commonly used as supporting ligands for a variety of transition metal-catalyzed processes, most notably in α-olefin polymerization. They are also precursors to valuable synthetic targets, such as chiral 1,2-diamines. Their synthesis is usually performed through acid-catalyzed condensation of amines with α-diketones. Despite the simplicity of this approach, accessing unsymmetrical α-diimines is challenging. Herein, we report the Ti-mediated intermolecular diimination of alkynes to afford a variety of symmetrical and unsymmetrical α-diimines through the reaction of diazatitanacyclohexadiene intermediates with C-nitrosos. These diazatitanacycles can be readily accessed in situ via the multicomponent coupling of TiNR imidos with alkynes and nitriles. The formation of α-diimines is achieved through formal [4 + 2]-cycloaddition of the C-nitroso to the Ti and γ-carbon of the diazatitanacyclohexadiene followed by two subsequent cycloreversion steps to eliminate nitrile and afford the α-diimine and a Ti oxo.

Azo synthesis meets molecular iodine catalysis

A metal-free synthetic protocol for azo compound formation by the direct oxidation of hydrazine HN-NH bonds to azo group functionality catalyzed by molecular iodine is disclosed. The strengths of this reactivity include rapid reaction times, low catalyst loadings, use of ambient dioxygen as a stoichiometric oxidant, and ease of experimental set-up and azo product isolation. Mechanistic studies and density functional theory computations offering insight into this reactivity, as well as the events leading to azo group formation are presented. Collectively, this study expands the potential of main-group element iodine as an inexpensive catalyst, while delivering a useful transformation for forming azo compounds.