352-32-9Relevant articles and documents
Liquid-phase fluorination of aromatic compounds by elemental fluorine
Conte, L.,Gambaretto, G. P.,Napoli, M.,Fraccaro, C.,Legnaro, E.
, p. 175 - 180 (1995)
The fluorination of aromatic compounds (benzene, toluene, phenol and benzoic acid) by elemental fluorine diluted with nitrogen has been investigated in various solvents (Freon 11, chloroform, methanol, trifluoroacetic acid, 2,2,2-trifluoroethanol, water) in order to define the influence of the experimental conditions on the reaction.Experiments have been carried out by varying the temperature, the substrate concentration in solution, the molar ratio of fluorine to substrate, and the concentration of fluorine in the fluorine/nitrogen mixture.In all cases, the effects on the yield of fluorinated products were studied.Monofluorinated compounds were mainly found in the reaction mixture, the isomers formed being in accord with the mechanism for electrophilic substitution.The highest yield of monofluorinated products was obtained with polar solvents and the following order was found: CFCl3 CHCl3 CH3OH CF3CH2OH CF3COOH.Interesting results were also found using particular additives (for instance, KOH or C4F9SO3Na in methanol) or water as the solvent.A direct relationship was observed between the yield of monofluorinated compounds and the molar ratio of fluorine to substrate, which has to be less than one in order to obtain high yields.In contrast, low selectivity, expressed as the yield ratio of ortho to para (or meta) isomers, was found. - Keywords: Fluorination; Aromatic compounds; Elemental fluorine; Isomer formation; Solvent effects; Additive effects
Direct fluorination of toluene using elemental fluorine in gas/liquid microreactors
J?hnisch,Baerns,Hessel,Ehrfeld,Haverkamp,L?we,Wille,Guber
, p. 117 - 128 (2000)
Direct fluorination of toluene, pure or dissolved in either acetonitrile or methanol, using elemental fluorine was investigated in gas/liquid microreactors, namely a falling film microreactor and a micro bubble column. The experiments included measurements at high substrate concentrations and at high fluorine contents diluted in a nitrogen carrier gas, e.g. up to 50vol.% fluorine. Results obtained were compared to the performance of a laboratory bubble column which served as a technological benchmark. Due to the formation of liquid layers of only a few tens of micrometers thickness, the microreactors provide very large interfacial areas, e.g. up to 40,000m2/m3. These values exceed by far those of the laboratory bubble column as well as all other devices applied in practice. The potential for enhancing mass and heat transfer was verified by several experiments resulting in an increase in conversion and selectivity for the microreactors compared to the laboratory benchmark. For the falling film microreactor, yields of up to 28% of monofluorinated ortho and para products for a degree of toluene conversion of 76% were obtained. These values are of the same order as described for the industrially applied Schiemann process. Space-time yields of the microreactors, when referred to the reaction channel volume, were orders of magnitude higher than those of the laboratory bubble column. Taking into account the construction material needed, the corresponding figures of merit, for an idealized geometry as well as the existing total reactor geometry, still indicate technological and economic benefits. A variation of operating conditions for the direct fluorination revealed that conversion can be increased in the microreactors by using higher fluorine-to-toluene ratios and reaction temperatures. The choice of solvent is also essential, with acetonitrile yielding much better results than methanol.
Grakauskas,V.
, p. 723 - 728 (1970)
A Mild, General, Metal-Free Method for Desulfurization of Thiols and Disulfides Induced by Visible-Light
Qiu, Wenting,Shi, Shuai,Li, Ruining,Lin, Xianfeng,Rao, Liangming,Sun, Zhankui
supporting information, p. 1255 - 1258 (2021/05/05)
A visible-light-induced metal-free desulfurization method for thiols and disulfides has been explored. This radical desulfurization features mild conditions, robustness, and excellent functionality compatibility. It was successfully applied not only to the desulfurization of small molecules, but also to peptides.
Full continuous flow synthesis process of fluorine-containing aromatic hydrocarbon compounds
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Paragraph 0081-0094, (2021/04/07)
The invention provides a full continuous flow synthesis process of a fluorine-containing aromatic hydrocarbon compound, and belongs to the technical field of preparation of halogenated hydrocarbon carbocyclic organic compounds. Arylamine and hydrogen fluoride are pumped into a thermostat A and a thermostat B respectively and flow into a micro-channel reactor C for a salt forming reaction after constant temperature treatment, and a sulfuric acid solution of nitrosyl sulfuric acid is pumped into a thermostat D and flows into a micro-channel reactor E together with a salt forming product flowing out of the micro-channel reactor C for a diazotization reaction after constant temperature treatment. A product flows into a micro-channel reactor F to be subjected to a thermal decomposition reaction, is cooled by a cooler G and then enters a three-phase separator H to be continuously separated, nitrogen is discharged after being subjected to spraying deacidification, a fluorine-containing aromatic hydrocarbon crude product is subjected to continuous alkali washing, continuous drying and continuous rectification to obtain a fluorine-containing aromatic hydrocarbon finished product, and a hydrofluoric acid and sulfuric acid mixture is subjected to continuous distillation to obtain a product. The hydrogen fluoride and sulfuric acid are obtained. The full continuous flow synthesis process has the advantages of high reaction yield, excellent product quality, good production safety, less pollutant discharge and the like.
Ruthenium-catalyzed selective hydroboronolysis of ethers
Kaithal, Akash,Kalsi, Deepti,Krishnakumar, Varadhan,Pattanaik, Sandip,Bordet, Alexis,Leitner, Walter,Gunanathan, Chidambaram
, p. 14390 - 14397 (2020/12/21)
A ruthenium-catalyzed reaction of HBpin with substituted organic ethers leads to the activation of C?O bonds, resulting in the formation of alkanes and boronate esters via hydroboronolysis. A ruthenium precatalyst, [Ru (p-cymene)Cl]2Cl2 (1), is employed, and the reactions proceed under neat conditions at 135 °C and atmospheric pressure (ca. 1.5 bar at 135 °C). Unsymmetrical dibenzyl ethers undergo selective hydroboronolysis on relatively electron-poor C?O bonds. In arylbenzyl or alkylbenzyl ethers, C?O bond cleavage occurs selectively on CBn?OR bonds (Bn = benzyl); in alkylmethyl ethers, selective deconstruction of CMe?OR bonds leads to the formation of alkylboronate esters and methane. Cyclic ethers are also amenable to catalytic hydroboronolysis. Mechanistic studies indicated the immediate in situ formation of a mono-hydridobridged dinuclear ruthenium complex [{(η6-p-cymene)RuCl}2(μ?H?μ?Cl)] (2), which is highly active for hydroboronolysis of ethers. Over time, the dinuclear species decompose to produce ruthenium nanoparticles that are also active for this transformation. Using this catalytic system, hydroboronolysis could be applied effectively to a very large scope of ethers, demonstrating its great potential to cleave C?O bonds in ethers as an alternative to traditional hydrogenolysis.