Fluorinated aromatic solvent

These facts and observations prompted our interest in a systematic investigation of metathesis reactions in fluorinated aromatic solvents as better... 

Samojlowicz C, Bieniek M, Pazio A, et al. The Doping effect of fluorinated aromatic solvents on the rate of ruthenium-catalysed olefin metathesis. Chem EurJ. 2011 17(46) 12981-12993. 

The high fluorine content contributes to resistance to attack by essentially all chemicals and oxidizing agents however, PCTFE does swell slightly ia halogenated compounds, ethers, esters, and selected aromatic solvents. Specific solvents should be tested. PCTFE has the lowest water-vapor transmission rate of any plastic (14,15), is impermeable to gases (see also Barrierpolymers), and does not carbonize or support combustion. 

The para-fluorine atoms on highly fluorinated aromatic compounds such as hexafluorobenzene or decafluorobiphenyl are activated and thus can go through aromatic nucleophilic substitution with bisphenols in an aprotic solvent at low temperatures (<80°C).121 123... 

In fact, fluorinated polyphosphazenes are usually considered to be extremely stable towards chemical agents and aggressives due to the presence of C-F bonds in the side phosphorus substituents. PTFEP, for instance, appears to be completely insensitive to several, most common, solvents (aliphatic and aromatic hydrocarbons, alcohols and water), to acids (e.g. acetic acid), and to bases (e.g. pyridine and concentrated NaOH solutions), although some decomposition could be observed in triethylamine and in concentrated H2SO4 [41]. Phos-phazene fluoroelastomers, moreover, are known to be completely insoluble in aromatic solvents [533] and petroleum-resistant materials [502-506,552]. 

As diazonium tetrafluoroborates are more soluble in strongly acidic media, the precipitation of the diazonium tetrafluoroborate from an auxiliary diazonium salt and alkaline tetrafluoroborate is preferred when the diazonium tetrafluoroborate is thought to be too soluble an increase of the ionic strength tends to decrease its solubility.3-129 However, some alkaline chloride can co-precipitate with the diazonium tetrafluoroborate. Consequently, the diazonium tetrafluoroborate yields can be a little optimistic and some chlorinated aromatics can be produced together with fluorinated aromatics during the dediazoniation step.3,171 To prevent such contamination, the diazonium tetrafluoroborate is washed with the minimum amount of chilled water, then with another polar solvent, such as an alcohol, and finally with a water-insoluble solvent, such as diethyl ether. When their decomposition points are not too low, diazonium tetrafluoroborates can also be purified by rccrystallization (in water or acetic acid) or by dissolution in acetone then salting out with diethyl ether.3... 

Aryltriazenes can also be decomposed by hydrogen fluoride in organic solution after extraction from their aqueous mother phase. In this case, hydrogen fluoride can be used in small excess but the nature of the solvent is crucial for example, tetrahydrofuran gives complex mixtures, dichloromethane promotes radical reactions (dimerizations, reductions) and acetic acid favors triazene decomposition before fluorination. Aromatic and haloaromatic compounds seem to be the best solvents.283 Such a technique, especially suited for the rapid introduction of an 18F atom, has been employed to produce [ 8F]haloperidol (3), the specific receptors of which have been localized in the brain by positron emission transaxial tomography.298... 

Fluoromethylbenzoic acids, metallation, 9, 26-27 Fluoro(phenyl) complexes, with platinum(II), 8, 482 Fluorosilanes, elimination in fluorinated alkene activation, 1, 732 in fluorinated aromatic activation, 1, 731 and hydrodefluorination, 1, 748 Fluorosilicate anions, hypercoordinated anions, 3, 484 Fluorotoluenes, metallation, 9, 21 Fluorous alkylstannanes, preparation, 3, 820 Fluorous biphasic system, as green solvent, 12, 844 Fluorous ligands, with supercritical carbon dioxide, 1, 82 Fluorous media... 

The reaction cannot be performed in fully fluorinated apolar solvents such as octafluorotoluene, which is probably because of missing polarization of fluorine that is necessary to attack the aromatic system. Polar solvents such as methanol or acetonitrile provide better environments for fluorination [308]. Formic acid as a protic solvent gives even better results and is also quite inert as this small molecule has no labile site for fluorine attack [274]. 

The S Ar reaction between thiolates and fluorinated aromatic systems requires, in general, high temperatures and polar, aprotic solvents. Furthermore, the selectivity is low. ... 

Fluorinated aromatic compounds. Finger and Kruse found that an aromatic chlorine or bromine atom activated by an o- or p-nitro group is subject to nucleophilic displacement by fluoride ipn on reaction with potassium fluoride in solvents such as succinonitrile, dimethyl formamide, or dimethyl sulfoxide. Unpublished work at Olin Mathieson Chemical Corporation indicates that best results are obtained with dimethyl sulfoxide as solvent and with potassium fluoride that has been finely ground (<100 mesh) and dried in a vacuum oven at 100° for at least 4 hrs. prior to use. In a typical case a mixture of p-nitrochlorobenzene, potassium fluoride, and dimethyl sulfoxide is stirred under reflux at 180° for 8-9 hrs., the cooled mixture... 

While entry 5 (CYPHOS IL 163) may be considered a borderline ionic, to date, of all the phosphonium-based ILs, it has received the most attention. Garayt et al. have patented a process to fluorinate aromatics [20]. Previously, Knifton, lin et al. have published and patented an enormous number of petrochemical applications using entry 5 as the solvent-alcohols from syngas [21-29], synthesis of acetaldehyde and acetic acid from syngas [40-45], synthesis of esters from syngas [46, 47], and synthesis of formamides and amines [48, 49],... 

It has also been found that the selectivity of fluoridation and yields of products can be improved by changing the reaction conditions [87]. In particular, the use of low polarity aromatic solvents (benzene or toluene) and/or the removal of inorganic salts result in dramatically increased yields of fluorinated arenes... 

OXSOL 100 is a purified grade of p-chlorobenzotrifluoride (PCBTF) with the characteristic odor of chlorinated aromatic solvents. OXSOL 100 is a clear water-white liquid with solvency characteristics similar to the cleissiceil chlorinated and fluorinated solvents. PCBTF has been commercially produced for over thirty years eis a chemiceil intermediate. OXSOL 100 has been used as a solvent since 1992 eis a replacement for solvents with Ozone Depletion Potential (ODP), Volatile Organic Compounds (VOC) and Hazardous Air Polluteuits (HAP). 

These materials are noted for their resistance to concentrated acids, except hydrofluoric acid and similar fluorinated chemicals, at elevated temperatures. They are also resistant to many aliphatic and aromatic solvents. They are not intended for use in alkaline or alternately acid and alkaline environments. This category of coatings includes ... 

Samojlowicz C, Bieniek M, Zarecki A, Kadyrov R, Grela K. The doping effect of fluorinated aromatic hydrocarbon solvents on the performance of common olefin metathesis catalysts application in the preparation of biologically active compounds. Chem Commun. 2008 (47) 6282-6284. 

Poor resistance to hydrocarbons, especially aromatic and halogenated compounds (chlorinated, fluorinated, etc.). Low mechanical properties and quiet high cost Excellent resistance to most chemical families including aromatic solvents, sulfur compounds, and amines. 

Good -regioselectivities in HAM can be achieved in nonpolar solvents such as THF. Dichloroethane or DMF inhibits the reaction or may lead to polymerization. Seller and later Vogt observed that in THF, toluene, and methyl-ferf-butyl ether the hydrogenation of the in situ formed enamine is the rate-determining step of the whole reaction sequence [37, 38]. Sy using a mixture of nonpolar aromatic solvents and methanol, the rate of this reaction step could be increased. Noteworthy, acidic alcohols, such as phenol or trifluoroethanol, support the undesired aldol condensation [58]. Acetals, which may derive from the reaction of the intermediate aldehyde with methanol, have never been observed in HAM [75]. Moreover, such acetals do not react under these conditions. A mixture of methanol and a fluorinated alcohol (trifluoroethanol, hexafluoroisopropyl alcohol) inhibits... 

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