- Electrocatalytic degradation of perfluorooctanoic acid by LaNixY1-xO3 (Y = Fe, Cu, Co, Sr) gas dispersion electrode
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Perfluorooctanoic acid (PFOA), as a refractory organic pollutant, seriously harms the environment and damages human health. Here, the electrocatalytic method was selected to degrade PFOA. In this work, perovskite catalysts doped with different elements, and corresponding gas diffusion electrodes (GDE) were prepared by the gel-sol method and citric acid complexation method. The crystal structure, microscopic morphology, and electrochemical properties of the LaNixY1-xO3 (Y = Fe, Cu, Co, Sr) perovskite catalyst electrode were analyzed by XRD, TEM, and CV. Moreover, the electrocatalytic performances of the as-prepared electrodes were assessed by the degradation of PFOA, and the Sr-doped GDE exhibited the highest degradation rate of PFOA. The optimum degradation conditions, such as the current density, pH, and initial concentration were also investigated. It was observed that when the current density was 20 mA/cm2, pH was 5, and initial concentration was 0.25 mmol/L, the Sr-doped GDE had the best degradation and defluorination efficiency of PFOA reached 90.0 % and 75.1 %, respectively. High performance liquid chromatography-mass spectrometry (HPLC-MS) was used to analyze the intermediate products of PFOA degradation and obtain the degradation pathway. With the combined action of [rad]OH and O2, PFOA was degraded by stepwise removal of CF2 groups, which were ultimately degraded into F? and CO2.
- Chen, Yongyang,Guo, Dan,Dong, Xiaochun,Li, Yahui,Huang, Yixuan,Chen, Hao,Li, Shanping
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- Preparation method of fluorine-containing carboxylic acid
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The invention discloses a preparation method of fluorine-containing carboxylic acid. The method comprises the following steps: reacting fluorine-containing carboxylate used as a raw material with an acylating chlorination reagent to obtain a corresponding mixture of fluorine-containing acyl chloride and fluorine-containing anhydride, and hydrolyzing and drying the mixture of fluorine-containing acyl chloride and fluorine-containing anhydride to obtain high-purity fluorine-containing carboxylic acid. The method provided by the invention is suitable for post-treatment of fluorine-containing carboxylic acid prepared by a fluorine-containing olefin (monoolefine, diene, cycloolefin and the like) oxidation method, replaces the traditional strong acid acidification and ether continuous extractionprocess, and is simpler, more convenient and more applicable; and the method can also be used for recovering and purifying a fluorine-containing carboxylate emulsifier. The purity of the fluorine-containing carboxylic acid prepared by the method can reach 98% or above.
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- Preparation method of perfluoroheptanoic acid
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The invention relates to the technical field of fluorochemical preparation, particularly a preparation method of perfluoroheptanoic acid. The method comprises the following steps: oxidizing dodecafluoroheptanol to obtain dodecafluoroheptanoic acid, carrying out reaction on the dodecafluoroheptanoic acid and thionyl chloride to obtain dodecafluoroheptanoyl chloride, carrying out fluorination on the dodecafluoroheptanoyl chloride to obtain perfluoroheptanoyl chloride, and hydrolyzing to obtain the perfluoroheptanoic acid. The technical process of preparing perfluoroheptanoic acid from dodecafluoroheptanol has the advantages of low energy consumption, no pollution and high yield (up to 75% or above), is easy to operate, and has higher competitive edges than the existing perfluoroheptanoic acid production technique.
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Paragraph 00114; 0015; 0016
(2017/07/22)
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- The effect of oxygen in the photocatalytic oxidation pathways of perfluorooctanoic acid
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The influence of oxygen in the photocatalytic oxidation of perfluorooctanoic acid (PFOA) promoted by a commercial nano-sized titanium dioxide was studied by testing the reaction in different conditions: static air, oxygen flux, nitrogen flux and pre-saturated nitrogen flux. The reaction was monitored by Total Organic Carbon (TOC) analysis and Ionic Chromatography (IC). Shorter chain perfluorocarboxylic acids (PFCAs; Cn, n = 1-7) intermediate degradation products were quantitatively determined by High-Performance Liquid Chromatography combined with Mass Spectrometry (HPLC-MS) analysis. The presence of shorter chain PFCAs in solution was also monitored by 19F NMR. The experimental findings are in agreement with two major oxidative pathways: Cn → Cn-1 photo-redox and β-scissions routes mediated by COF2 elimination. Depending on the experimental conditions, the mutually operating mechanisms could be unbalanced up to the complete predominance of one pathway over the other. In particular, the existence of the β-scissions route with COF2 elimination was corroborated by the isolation and characterization of carbonyl difluoride, a predicted fluorinated decomposition by-product.
- Sansotera, Maurizio,Persico, Federico,Rizzi, Valentina,Panzeri, Walter,Pirola, Carlo,Bianchi, Claudia L.,Mele, Andrea,Navarrini, Walter
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p. 159 - 168
(2015/11/10)
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- A novel liquid plasma AOP device integrating microwaves and ultrasounds and its evaluation in defluorinating perfluorooctanoic acid in aqueous media
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A simplified and energy-saving integrated device consisting of a microwave applicator and an ultrasonic homogenizer has been fabricated to generate liquid plasma in a medium possessing high dielectric factors, for example water. The microwave waveguide and the ultrasonic transducer were interconnected through a tungsten/titanium alloy stick acting both as the microwave antenna and as the horn of the ultrasonic homogenizer. Both microwaves and ultrasonic waves are simultaneously transmitted to the aqueous media through the tungsten tip of the antenna. The microwave discharge liquid plasma was easily generated in solution during ultrasonic cavitation. The simple device was evaluated by carrying out the degradation of the perfluorooctanoic acid (PFOA), a system highly recalcitrant to degradation by conventional advanced oxidation processes (AOPs). PFOA is 59% degraded in an aqueous medium after only 90 s of irradiation by the plasma. Intermediates were identified by electrospray mass spectral techniques in the negative ion mode.
- Horikoshi, Satoshi,Sato, Susumu,Abe, Masahiko,Serpone, Nick
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experimental part
p. 938 - 942
(2012/03/08)
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- Electrochemical and Photocatalytic Decomposition of Perfluorooctanoic acid with a hybrid reactor using a boron-doped diamond electrode and TiO2 photocatalyst
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The efficient decomposition of environmentally persistent perfluorooctanoic acid (PFOA) was achieved by a hybrid of electrolysis and photocatalysis. The rate constant of PFOA decomposition in the hybrid system was larger than the sum of the constants in electrolysis-only and photocatalysis-only systems. The hybrid system was able to accelerate the PFOA decomposition by complementally support of two kinds of reaction kinetics. These results could be useful for development of a new continuous system for practical treatment of waste water containing perfluorinated acids.
- Ochiai, Tsuyoshi,Moriyama, Hirofumi,Nakata, Kazuya,Murakami, Taketoshi,Koide, Yoshihiro,Fujishima, Akira
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supporting information; body text
p. 682 - 683
(2011/08/07)
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- Efficient mineralization of hydroperfluorocarboxylic acids with persulfate in hot water
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The persulfate (S2O82-)-induced decomposition of hydroperfluorocarboxylic acids (H-PFCAs), that is, HCnF2nCOOH (n = 4, 6, and 8), in hot water was investigated, and the results were compared with the
- Hori, Hisao,Murayama, Misako,Inoue, Naoko,Ishida, Kyoko,Kutsuna, Shuzo
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experimental part
p. 131 - 136
(2010/08/20)
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- Photocatalytic decomposition of environmentally persistent perfluorooctanoic acid
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Perfluorooctanoic acid was photocatalytically decomposed by using TiO 2/Ni-Cu, and a small bias potential (-0.1 V) applied on TiO 2/Ni-Cu electrode greatly enhanced its decomposition. Copyright
- Chen, Jing,Zhang, Pengyi,Zhang, Li
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p. 230 - 231
(2007/10/03)
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- Degradation of fluorotelomer alcohols: A likely atmospheric source of perfluorinated carboxylic acids
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Human and animal tissues collected in urban and remote global locations contain persistent and bioaccumulative perfluorinated carboxylic acids (PFCAs). The source of PFCAs was previously unknown. Here we present smog chamber studies that indicate fluorotelomer alcohols (FTOHs) can degrade in the atmosphere to yield a homologous series of PFCAs. Atmospheric degradation of FTOHs is likely to contribute to the widespread dissemination of PFCAs. After their bioaccumulation potential is accounted for, the pattern of PFCAs yielded from FTOHs could account for the distinct contamination profile of PFCAs observed in arctic animals. Furthermore, polar bear liver was shown to contain predominately linear isomers (>99%) of perfluorononanoic acid (PFNA), while both branched and linear isomers were observed for perfluorooctanoic acid, strongly suggesting a sole input of PFNA from "telomer"-based products. The significance of the gas-phase peroxy radical cross reactions that produce PFCAs has not been recognized previously. Such reactions are expected to occur during the atmospheric degradation of all polyfluorinated materials, necessitating a reexamination of the environmental fate and impact of this important class of industrial chemicals.
- Ellis, David A.,Martin, Jonathan W.,De Silva, Amila O.,Mabury, Scott A.,Hurley, Michael D.,Sulbaek Andersen, Mads P.,Wallington, Timothy J.
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p. 3316 - 3321
(2007/10/03)
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- Ozonolysis of alkenes and studies of reactions of polyfunctional compounds: LXV.* Ozonolysis of perfluoro-1-octene in Freon-113
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Ozonization of perfluoro-1-octene in Freon-113 yields the corresponding ozonide whose catalytic hydrogenation over Pd/C or hydride reduction leads to formation of perfluoroheptanoic acid; the reduction with lithium aluminum hydride gives 2,2,3,3,4,4,5,5,6,6,7,7,7-tridecafluoro-1-heptanol. Ozonization of perfluoro-1-octene in Freon-113 containing excess (≥3 equiv) alcohol affords the corresponding perfluoroheptanoic acid ester.
- Odinokov,Akhmetova,Bazunova,Savchenko,Paramonov,Khalilov
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p. 321 - 325
(2007/10/03)
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- Ozonolysis of perfluoroalkenes and perfluorocycloalkenes
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Ozonolysis of 1-methoxyperfluorocyclobutene in Freon-113 followed by hydrogenation of the reaction products gave methyl hydrogen perfluorosuccinate. Under similar conditions, perfluorooct-1- and -2-enes and 4-trifluoromethyl-1,1,1,2,3,4,5,5,5-nonafluoropent-2-ene were converted into perfluorinated heptanoic, hexanoic, and isobutyric acids, respectively.
- Odinokov,Akhmetova,Savchenko,Bazunova,Fatykhov,Zapevalov
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p. 1190 - 1191
(2007/10/03)
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- Multiple pathways in cyclodextrin-catalyzed hydrolysis of perfluoroalkylamides
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The hydrolysis of p-nitroanilide of perfluoroalkanoic acids, CF3(CF2)nCO-, with n = 1, 2, 3, 5, 6, and 7, 1a-f, was studied in the presence of β-cyclodextrin (CD). All reactions were catalyzed by CD through the formation of a 1:1 and 1:2 inclusion complexes. The association equilibrium constants for the 1:1 complexes were dependent on the number of carbons of the fluoroalkyl chain, whereas those of the 1:2 complexes were almost independent. These results indicate that, in the former case, the perfluoroalkyl chain is included, while in the latter, the CD unit encloses the aryl ring. For compounds 1a,b both complexes were more reactive than the substrate itself. The ratio of the reaction of complexed to uncomplexed substrate had its highest value for 1a in the case of the 1:1 complex, and for 1b, the 1:2 complex. This is attributed to the geometry of the complexes. Although compounds 1c-e reacted at the same rates in the free or 1:1 complexed form, CD accelerated the reactions because of an increase of the pKa of the substrate, which results in a higher concentration of the neutral reactive substrate at the same pH. Compound 1f formed aggregates even at 10-6 M concentration, and CD-induced deaggregation resulted in catalysis of the reaction.
- Granados, Alejandro,De Rossi, Rita H.
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p. 3690 - 3696
(2007/10/02)
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- An improved synthesis of perfluorocarboxylic acids
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Perfluoroalkyl iodides C(n)F(2n+1) CF2I (3 2CO2H in 91% yield, by reaction with zinc-copper couple in the presence of solid carbon dioxide in trimethyl phosphate as the solvent.
- Benefice-Malouet,Blancou,Itier,Commeyras
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p. 647 - 648
(2007/10/02)
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- A NEW METHOD FOR THE PREPARATION OF PERFLUOROCARBOXYLIC ACIDS
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The reaction of both primary perfluoroalkyl iodides and bromides containing 3-12 carbon atoms with a rongalite-NaHCO3 reagent in aqueous dipolar aprotic solvents, such as DMF or DMSO, has been investigated.The reaction gave sodium perfluorocarboxylates in 51-86percent yields, and these were transformed to the respective perfluorocarboxylic acids by treatment with sulfuric acid.This provides a new method for the synthesis of perfluorocarboxylic acids.
- Huang, Bing-Nan,Haas, A.,Lieb, M.
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- REACTIVITE DES PERFLUOROIODOALCANES AVEC LES CARBONATES ET PYROCARBONATES D'ALCOYLES EN PRESENCE DE COUPLE METALLIQUE ZINC-CUIVRE
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Perpluoroalkyl iodides RFI, in dissociating solvents, in the presence of zinc-copper couple give perfluoroorganic compounds RFZnI, which reac with alkyl carbonates and pyrocarbonates to give perfluorocarboxylic acids and perfluorocarboxylis esters of industrial interest.
- Benefice, S.,Blancou, H.,Commeyras, A.
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p. 1541 - 1544
(2007/10/02)
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- UTRASOUND-PROMOTED DIRECT CARBOXYLATION OF PERFLUOROALKYL IODIDES
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Perfluoroalkyl iodides were directly carboxylated with Zn and CO2 under utrasonic irradiation affording the corresponding perfluoroalkanoic acids.
- Ishikawa, Nobuo,Takahashi, Mitsuru,Sato, Takehiko,Kitazume, Tomoya
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p. 585 - 588
(2007/10/02)
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- SYNTHESE D'ACIDES PERFLUORES DE HAUTS POIDS MOLECULAIRES
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Perfluorinated olefins of general formula CF3-(CF2)p-CF=CF-(CF2)m-CF3 (3 /= m + p /= 25) are oxidized by potassium permanganate or ruthenium tetroxide.The linear high molecular weight perfluorinated carboxylic acids so obtained are characterized by 19F N.M.R. spectroscopy.
- Battais, A.,Boutevin, B.,Pietrasanta, Y.,Sierra, P.
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- OXYDATION ANODIQUE DE IODOPERFLUOROALCANES DANS LES ACIDES PERFLUOROALCANESULFONIQUES. PREPARATION DE NOUVEAUX ESTERS SULFONIQUES TOTALEMENT FLUORES RFSO3R'F A LONGUES CHAINES
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Perfluorinated sulphonic esters RFSO3R'F and fluorosulphates FSO3R'F, are easily obtained by anodic oxidation of iodoperfluoroalkanes R'FI in perfluoroalkene sulphonic acids RFSO3H (RF=CF3, C2F5, C4F9) and fluorosulphuric acid.With di-iodo compound I(CF2)4I, the mono and the diester can be selectively obtained.The alkaline hydrolysis of these esters produces perfluorinated carboxylic compounds.Polyfluorinated iodide R'FCH2CH2I are also oxidized in similar conditions.The mechanism of the electrolytic reaction is discussed.
- Germain, A.,Commeyras, A.
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p. 487 - 492
(2007/10/02)
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- Process for the preparation of derivatives of fluoroalkane-carboxylic and perfluoroalkane-sulfinic acids
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A process is disclosed for the preparation of derivatives of perfluoroalkanecarboxylic acids and perfluoroalkanesulphinic acids by reacting a perfluoroalkylhalide having the general formula RF X, in which X represents an atom of chlorine, bromine, or iodine, and RF represents an unbranched or branched perfluorinated chain containing from 2 to 12 carbon atoms; with CO2 or SO2 in a solvent medium and in the presence of activated or unactivated zinc.
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