375-83-7Relevant academic research and scientific papers
A novel liquid plasma AOP device integrating microwaves and ultrasounds and its evaluation in defluorinating perfluorooctanoic acid in aqueous media
Horikoshi, Satoshi,Sato, Susumu,Abe, Masahiko,Serpone, Nick
experimental part, p. 938 - 942 (2012/03/08)
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.
Gas-phase NMR studies of the thermolysis of perfluorooctanoic acid
Krusic, Paul J.,Marchione, Alexander A.,Roe, D. Christopher
, p. 1510 - 1516 (2007/10/03)
The thermolysis of perfluorooctanoic acid (CF3(CF 2)6COOH) has been studied kinetically by high-temperature gas-phase NMR in both sodium borosilicate glass and quartz ampoules. In both cases, 1-H-perfluoroheptane is the major product, but the decomposition is considerably slower in quartz. The decomposition in borosilicate ampoules at 307°C is greatly accelerated by the presence of crushed borosilicate glass and the reaction appears to be completely heterogeneous. Perfluoro-1-heptene is produced as a minor product and time-of-flight secondary ion mass spectrometry (ToF-SIMS) examination of the inner surface of the borosilicate glass ampoule after reaction reveals the presence of NaF. The thermolysis in quartz ampoules was studied by ex situ heating in the temperature range 355-385°C and produced moderate amounts of perfluoro-1-heptene and SiF4 in addition to 1-H-perfluoroheptane. Thermolysis in the presence of added crushed quartz accelerates the decomposition, as does increasing the concentration of perfluorooctanoic acid or carrying out the thermolysis in the presence of water. The thermolysis of perfluorooctanoic acid thus proceeds at widely different rates depending on concentration and on the physical and chemical environment. By contrast, the pyrolysis of ammonium perfluorooctanoate is more facile by orders of magnitude and proceeds by first-order kinetics at essentially the same rates in both quartz and borosilicate ampoules with an estimated half-life of 2 s at 307°C.
Yield improvement in the electrochemical production of pefluorooctanoic acid
Napoli, M.,Scipioni, A.,Gambaretto, G. P.,Carlini, F. M.,Bertola, M.
, p. 261 - 264 (2007/10/02)
The possibility of obtaining real yield improvements in the industrial electrochemical production of perfluorooctanoic acid is discussed on the basis of recent experimental data obtained using perfluorohexyl acetyl chloride in place of octanoyl chloride as a starting material.In particular, the effect of the non-formation of cyclic byproducts on the yield of perfluoro-octanoic acid has been examined, as well as considering previous results obtained starting from a different partially fluorinated precursor, 4-perfluorobutyl butanoyl chloride.The yield of perfluoro-octanoic acid from perfluorohexyl acetyl chloride was less than expected, because of an accompanying increase in perfluoro-n-heptane formation.
A NEW METHOD FOR THE PREPARATION OF PERFLUOROCARBOXYLIC ACIDS
Huang, Bing-Nan,Haas, A.,Lieb, M.
, p. 49 - 62 (2007/10/02)
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.
