110-16-7Relevant articles and documents
Catalytic Aerobic Oxidation of Biomass-based Furfural into Maleic Acid in Aqueous Phase with Metalloporphyrin Catalysts
Huang, Yi,Wu, Chunyan,Yuan, Wenwen,Xia, Yongmei,Liu, Xiang,Yang, Huamei,Wang, Haijun
, p. 786 - 794 (2017)
Catalytic oxidation of renewable furfural into valuable maleic acid in aqueous solutions using metalloporphyrin catalysts was investigated for the first time. The synthesized catalysts were characterized by FT-IR, UV–vis, 1H NMR, elemental analysis, and TGA. The catalysts varied in metal active sites and functional groups, which had different effects on their catalytic activity. Furthermore, the effects of temperatures, reaction time, catalyst loading, and oxygen pressure were studied in detail. Maleic acid could be achieved in 44% yield by using FeT(p-Cl)PPCl as catalyst under optimal conditions. Finally, FeT(p-Cl)PPCl could be reused in five consecutive runs without a significant loss of activity.
Application of anodic oxidation, electro-Fenton and UVA photoelectro-Fenton to decolorize and mineralize acidic solutions of Reactive Yellow 160 azo dye
Bedolla-Guzman, Alejandro,Sirés, Ignasi,Thiam, Abdoulaye,Peralta-Hernández, Juan Manuel,Gutiérrez-Granados, Silvia,Brillas, Enric
, p. 307 - 316 (2016)
The degradation of 100 cm3 of a solution with 0.167 mmol dm-3 Reactive Yellow 160 (RY160) azo dye in sulfate medium at pH 3.0 has been comparatively studied by anodic oxidation with electrogenerated H2O2 (AO-H2O2), electro-Fenton (EF) and UVA photoelectro-Fenton (PEF). Trials were carried out with a stirred tank reactor equipped with a boron-doped diamond (BDD) anode and an air-diffusion cathode for H2O2 production, upon addition of 0.50 mmol dm-3 Fe2+ as catalyst in EF and PEF. The solution was slowly decolorized by AO-H2O2 because of the low rate of reaction of the azo dye and its colored products with hydroxyl radicals generated at the BDD anode from water oxidation. The color loss was enhanced in EF by the larger oxidation ability of hydroxyl radicals produced in the bulk from Fenton's reaction between added Fe2+ and generated H2O2, whereas the solution was more rapidly decolorized by PEF owing to the additional generation of hydroxyl radicals from the photolysis of Fe(III)-hydroxy complexes by UVA light. The relative mineralization ability of the processes also increased in the sequence AO-H2O2 -2. The influence of current density and RY160 concentration on the performance of all processes was assessed. Final carboxylic acids like maleic, fumaric, tartronic, acetic, oxalic, oxamic and formic were quantified by ion-exclusion HPLC. All these acids were totally removed by PEF, but the formation of small amounts of other highly recalcitrant products impeded the total mineralization. Chloride, sulfate, ammonium and, to a smaller extent, nitrate ions were released to the solution from the heteroatoms of the azo dye in all cases.
Fabrication of a stable Ti/Pb-TiOxNWs/PbO2 anode and its application in benzoquinone degradation
Guo, Yingjuan,Tang, Changbin,Xue, Juanqin,Yu, Lihua,Zhang, Lihua
, (2021)
To delay passivation of a titanium (Ti) substrate as well as enhance adhesion between an electrodeposited PbO2 coating and the Ti substrate, a titanium-lead composite oxide nanowire (Pb-TiOxNWs) intermediate layer was formed in situ on the surface of porous Ti by alkali etching, ion substitution, and high-temperature calcination. At the same time, Ti/PbO2 and Ti/TiO2NWs/PbO2 electrodes with porous Ti as a matrix were prepared for comparison. The surface structure and morphology of the prepared intermediate layer and the PbO2 coating were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The influences of the composite oxide intermediate layer on the electrochemical performance of the PbO2 electrode were analyzed by cyclic voltammetry (CV), linear sweep voltammetry (LSV), and AC impedance spectroscopy (EIS). Accelerated lifetime tests were performed for electrodes with and without different intermediate layers. The results showed that PbOx was incorporated into the titanium dioxide three-dimensional network structure, resulting in formation of Pb-TiOxNWs. The surface of the Ti/Pb-TiOxNWs/PbO2 electrode was denser due to the smaller particle size of PbO2. The preferred crystal orientation of β(110) was observed for PbO2 deposited on Ti/Pb-TiOxNWs. The oxygen evolution potential reached a maximum of 2.19 V for Ti/Pb-TiOxNWs/PbO2. Accelerated life tests showed that compared with Ti/PbO2 and Ti/TiO2NWs/PbO2, the electrode life of Ti/Pb-TiOxNWs/PbO2 was increased by 91.7% and 35.3%, respectively. Therefore, it can be concluded that significantly improved morphology and electrochemical performance were achieved for titanium-based PbO2 electrodes by the addition of a Pb-TiOxNWs intermediate layer. In particular, the electrochemical stability of the PbO2 coating electrodes was improved markedly by the Pb-TiOxNWs intermediate layer. The electrodes were used for electrochemical oxidation of benzoquinone in wastewater (100 mg/L). It was found that chloride ions played a critical role in improving the current efficiency of electro-oxidative degradation. Under the same conditions, the COD removal rate in the presence of NaCl was 45% higher than in the presence of sulfate. The results of HPLC analysis of the intermediate products indicated that the oxidants electro-generated by chloride ions had stronger ring-opening and mineralization capabilities than those electro-generated by sulfate ions.
Decomposition of phenolic endocrine disrupting chemicals by potassium permanganate and γ-ray irradiation
Abe, Yasuhiro,Takigami, Machiko,Sugino, Kouji,Taguchi, Mitsumasa,Kojima, Takuji,Umemura, Tomonari,Tsunoda, Kin-Ichi
, p. 1681 - 1685 (2003)
The decomposition of phenolic endocrine disrupting chemicals (P-EDCs), such as phenol, 4-t-butylphenol (BuP), and bisphenol A (BPA), in aqueous solutions by potassium permanganate (KMnO4) was studied, and its efficiency was compared with that of hydroxyl radicals (OH?) generated by 60Co γ-ray irradiation. Various organic acids and inorganic carbon were formed in the decomposition of P-EDCs due to either KMnO4 or OH?. They were formed via direct aromatic ring cleavage in the case of KMnO4 and via OH? addition-substitution reactions, followed by aromatic ring cleavage, in the case of OH?. Comparing the decrease in the P-EDCs based on the number of electrons, the amount of KMnO4 spent to completely eliminate BuP and BPA was comparable to that of OH?. Although three-times more KMnO4 was needed for phenol decomposition than OH?, the complete conversion of phenol into organic acids and inorganic carbon was achieved with 720 μM of electrons in both cases.
Reactions of Ozone with 1-(m-Substituted phenylazo)-2-naphthol-6-sulfonic Acids in Aqueous Solutions
Onari, Yasuo
, p. 2526 - 2530 (1985)
The substituent effect on the ozone decoloration of 1-(m-substituted phenylazo)-2-naphthol-6-sulfonic acids (PANSA) in aqueous solutions was investigated.Both the acidities of PANSA and the variation of the ozone decoloration rates of them increased compared to those of the corresponding 1-(m-substituted phenylazo)-2-naphthol-3,6-disulfonic acids (PANDSA).The relationships between the decoloration rates and the indexes (pKOH and ?m values) of the basicities of the dyes, however, indicated nearly the same characteristics between the data of these two series of dyes, and the ozone decoloration reactions of PANSA appeared to proceed by nearly the same mechanism as those of PANDSA.The changes of the keto-enol ratios of the dyes with their ozone decolorations suggested that the decoloration rates might rise as the reduction rates of their keto-enol ratios increased.It seems likely that the chief organic product that was finally produced in these resctions is oxalic acid.
Heavy atom effects reveal diradical intermediates. I. An aqueous Diels- Alder reaction
Telan, Leila A.,Firestone, Raymond A.
, p. 14269 - 14280 (1999)
The aqueous Diels-Alder reaction between 2-methylfuran and maleic acid in water is 99.9% stereospecific. Addition of heavy but not light atom salts to the retrodiene reaction reduces the degree of stereospecificity significantly. Taking into account the relatively low concentration (3.5-7 M) of heavy atoms, and the rapid fall off of the heavy atom effect with distance, these results show that a large portion, if not all of the Diels Alder occurs via diradical intermediates.
Degradation of the Cellulosic Key Chromophore 5,8-Dihydroxy-[1,4]-naphthoquinone by Hydrogen Peroxide under Alkaline Conditions
Zwirchmayr, Nele Sophie,Hosoya, Takashi,Henniges, Ute,Gille, Lars,Bacher, Markus,Furtmüller, Paul,Rosenau, Thomas
, p. 11558 - 11565 (2017)
5,8-Dihydroxy-[1,4]-naphthoquinone (DHNQ) is one of the key chromophores in cellulosic materials. Its almost ubiquitous presence in cellulosic materials makes it a target molecule of the pulp and paper industry's bleaching efforts. In the presented study, DHNQ was treated with hydrogen peroxide under alkaline conditions at pH 10, resembling the conditions of industrial hydrogen peroxide bleaching (P stage). The reaction mechanism, reaction intermediates, and final degradation products were analyzed by UV/vis, NMR, GC-MS, and EPR. The degradation reaction yielded C1-C4 carboxylic acids as the final products. Highly relevant for pulp bleaching are the findings on intermediates of the reaction, as two of them, 2,5-dihydroxy-[1,4]-benzoquinone (DHBQ) and 1,4,5,8-naphthalenetetrone, are potent chromophores themselves. While DHBQ is one of the three key cellulosic chromophores and its degradation by H2O2 is well-established, the second intermediate, 1,4,5,8-naphthalenetetrone, is reported for the first time in the context of cellulose discoloration.
Photosensitized Cis-Trans Isomerization in Aqueous Solution. pH Effect on the Efficincy of Triplet-Triplet Energy Transfer to Maleic Acid
Gupta, Atma,Mukhtar, Rehana,Seltzer, Stanley
, p. 2356 - 2363 (1980)
Aromatic ketones, made water soluble by introduction of ionic substituents, photosensitize cis trans isomerization in the maleic-fumaric acid system.The photostationary-state cis/trans ratio depends on the triplet energy of the sensitizer and the pH of the medium.All sensitizers studied show a pH effect on the cis/trans ration which varies from 2.8 to 1.2 and is independent of whether the sensitizer is negatively or positively charged.Parallel quenching studies show the major part of this stems from a pH effect on the relative rates of energy transfer from the sensitizer to cis and trans acids.A smaller pH effect, in the opposite direction, is found with the rrelative rates of decay of the triplet to ground-state cis and trans isomers.Direct photoisomerization was also found to show this same pH effect in the decay of the lowest excited singlet to ground-state molecules.A rationalization is presented.
Synthesis of maleic acid from renewable resources: Catalytic oxidation of furfural in liquid media with dioxygen
Shi, Song,Guo, Huajun,Yin, Guochuan
, p. 731 - 733 (2011)
Developing novel technologies to obtain fuel and organic chemicals from renewable resources has been the immediate issue in academic and industrial communities. The present work introduces a new route to synthesize maleic acid from the renewable furfural. The current data reveal that, using dioxygen as oxidant, the simple copper salts can catalyze oxidation of furfural to maleic acid in aqueous solution. The combination of copper nitrate with phosphomolybdic acid could achieve a 49.2% yield of maleic acid with selectivity of 51.7%. The major challenge for this route is how to avoid the polymerization of furfural to resins under oxidative conditions.
Photocatalytic ozonation for degradation of 2-sec-butyl-4,6-dinitrophenol (DNBP) using titanium dioxide: Effect of operational parameters and wastewater treatment
Mousanejad,Khosravi,Tabatabaii,Khataee,Zare
, p. 711 - 722 (2014)
The results of degradation efficiency of 2-sec-butyl-4,6-dinitrophenol (DNBP) in a batch system by various advanced oxidation processes revealed the order of TiO2/UV/O3 > TiO2/O3 > UV/O3 > O3 > UV/TiO2. All processes followed pseudo-first order kinetics. The influence of operational parameters such as initial pH, initial concentration of DNBP, ozone and catalyst dosage on the TiO2/UV/O3 process, which was the most significant investigated method. The ozone dosage was found to have the noticeable impact on the process; however, initial pH and TiO2 dosage were less effective. The mineralization of 40 mg/L of DNBP and petrochemical wastewater under the obtained optimal conditions was monitored by total organic carbon and chemical oxygen demand, respectively. The results demonstrated that the TiO 2/UV/O3 process was a very effective method for degradation and mineralization of DNBP in aqueous solutions and industrial wastewater. The degradation intermediates were identified by GC-MS.
