Nitration of fluorine

NaNC>3 and cone. H2SC>4 gave 5-chloro I-nitrobenzo[2,l,3]selenadiazole 142 in 90% yield (Equation 7) <2004RJC428>. An improved method for nitration of fluorine-substituted benzo[2,l,3]selenadiazoles was also reported. Treatment of a variety of benzo[2,l,3]selenadiazoles with commercially available 90% nitric acid dissolved in a mixture of methanesulfonic acid and phosphorus pentoxide at room temperature gave 4-nitrobenzo[2,l,3]sclc-nadiazoles in 81-94% yield <2004JHC1023>. The obtained 2,1,3-benzoselenadiazoles were used as precursors to o-phenylenediamines (see Section 6.12.5.8). 

Nitration of Fluorinated Aromatics Using Trillatoboric Acid General Procedure ... 

Nitration of Fluorinated Aromatics Using Triflatoboric Acid General Procedure 4... 

Nitration of Fluorinated Aromatics Using Zeolite Beta as a Catalyst General Procedure 5... 

Fluorinated Acids. This class of compounds is characterized by the strength of the fluorocarbon acids, eg, CF COOH, approaching that of mineral acids. This property results from the strong inductive effect of fluorine and is markedly less when the fluorocarbon group is moved away from the carbonyl group. Generally, their reactions are similar to organic acids and they find apphcations, particularly trifluoroacetic acid [76-05-1] and its anhydride [407-25-0] as promotors in the preparation of esters and ketones and in nitration reactions. 

An ipso attack on the fluorine carbon position of 4-fIuorophenol at -40 °C affords 4-fluoro-4-nitrocyclohexa-2 5-dienone in addtion to 2-nitrophenol The cyclodienone slowly isomenzes to the 2-nitrophenol Although ipso nitration on 4-fluorophenyl acetate furnishes the same cyclodienone the major by-product is 4 fluoro-2,6-dinitrophenol [25] Under similar conditions, 4-fluoroanisole pnmar ily yields the 2-nitro isomer and 6% of the cyclodienone The isolated 2 nitro isomer IS postulated to form by attack of the nitromum ion ipso to the fluorine with concomitant capture of the incipient carbocation by acetic acid Loss of the elements of methyl acetate follows The nitrodienone, being the keto tautomer of the nitrophenol, aromatizes to the isolated product [26] (equation 20) Intramolecular capture of the intermediate carbocation occurs in nitration of 2-(4-fluorophenoxy)-2-methyIpropanoic acid at low temperature to give the spiro products 3 3-di-methyl-8 fluoro 8 nitro-1,4 dioxaspiro[4 5]deca 6,9 dien 2 one and the 10-nitro isomer [2d] (equation 21)... 

A slight but systematic decrease in the wave number of the complexes bond vibrations, observed when moving from sodium to cesium, corresponds to the increase in the covalency of the inner-sphere bonds. Taking into account that the ionic radii of rubidium and cesium are greater than that of fluorine, it can be assumed that the covalent bond share results not only from the polarization of the complex ion but from that of the outer-sphere cation as well. This mechanism could explain the main differences between fluoride ions and oxides. For instance, melts of alkali metal nitrates display a similar influence of the alkali metal on the vibration frequency, but covalent interactions are affected mostly by the polarization of nitrate ions in the field of the outer-sphere alkali metal cations [359]. 

The molecular models upon which the theoretical intensity curves of Fig. 4 are based have. been chosen to distinguish between the three most probable configurations of fluorine nitrate. The... 

The investigation of methyl azide, methyl nitrate, and fluorine nitrate by electron diffraction is shown to lead to configurations of the molecules corresponding in each case to resonance between two important valence-bond structures. The unimportance of a third otherwise reasonable structure for these molecules as well as for nitrous oxide is ascribed to instability due to the presence of electric charges of the same sign on adjacent atoms. It is shown that the differ-... 

Aromatic hydrazines, 13 573 Aromatic hydrocarbons, 18 593 biodegradability of, 25 826 composition of, 25 168 as diluents, 10 430 fluorinated, 11 866 nitration of, 17 161 separation of, 10 782-785 as solvents for poly(ethylene oxide),... 

A weight of compound, containing about 0-05 g. of fluorine, was dissolved in 10 ml. of dry alcohol and metallic sodium (about 0 5 g., i.e. at least 5 equivalents) was added. After the sodium had dissolved, the mixture was gently heated under reflux for 5 min.,8 and then washed out with about 100 ml. of water into a beaker, made acid to bromophenol blue with dilute nitric acid and then just alkaline with 10 per cent sodium hydroxide solution. Three ml. of 10 per cent sodium chloride solution were added and the solution was diluted to 250 ml. One ml. of concentrated hydrochloric acid was added, and the solution heated on a water-bath to about 80°. Then 5-0 g. of finely powdered A.R. lead nitrate were added with stirring (still at 80°). As soon as all the lead nitrate had dissolved, 5-0 g. of crystalline sodium acetate were added, with vigorous stirring. The product was then heated on the water-bath for 15 min. and cooled in ice, and the precipitate was filtered off on a Swedish filter paper. It was washed once with water, four times with saturated PbClF solution... 

Willard, H. H. and Winter, O. B. (1953). Volumetric method for determination of fluorine using thorium nitrate. Industr. Engng Chem. (Anal, ed.), 5, 7. 

Fluorine nitrate may be prepared by the action of fluorine on nitric acid F2 + HNO3 FNO3 + HF... 

L.H. Andersson, B. Gelin, The separation of fluorine by Willard-Winter distillation and its determination by titration with thorium nitrate or by spectrophotometric measurement, FOA Rep. 1 (1967) 1-5. 

Ruff Kwasnick (Ref 2) showed that it was better to use 100% nitric acid at RT in a quartz apparatus. It can also be made by che action of fluorine on K nitrate... 

The exceptional character o fluorine.—Fluorine has a little more individuality, so to speak, than the other three members of the family (1) There are no compounds of oxygen and fluorine (2) Chlorine, bromine, and iodine or the haloid acids show no signs of the remarkable effect of hydrofluoric acid and of fluorine on silicon (3) The solubilities of the sulphates, nitrates, and chlorides of barium, strontium, calcium, and magnesium decrease with increasing at. wt. of the metal, while the solubilities of the hydroxides increase the solubilities of the iodides, bromides, and chlorides... 

Knowledge was accumulated systematically from the start of the present century, and has been summarized.9 A major contribution was made by Holleman and his group in the Netherlands in the period up to 1915. Various fluorobenzene derivatives having one or more substituents (N02, NH2, Me, C02H, OMe, SOsH or halo) were made and orientated. The ratio of isomers formed in the nitration of fluorobenzene was determined (mainly para some ortho). Also, fluorobenzene was itself resistant to attack by nucleophiles, but if a nitro group was present, particularly in the para position, fluorine was replaced much more readily. 

Silver differs markedly from copper in forming few 0x3 compounds. One of these is silver oxynitratc or silvcrdl, III) nitrate which has the empirical formula AgO 145(1 03)3453, in which the average oxidation number of silver is 2.448, It is prepared by action of fluorine upon aqueous silver nitrate or is obtained as an anodic deposit by electrolysis of silver nitrate in dilute HNO3. 

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