Sodium fluoride formation

By mistake, sodimn was added to excess liquid perfluoroalkylmethanol in the absence of tire diluent which had previously moderated the reaction. Vigorous initial reaction culminated in an explosion which destroyed the flask and attached glassware and cracked tire fume cupboard window, this was attributed to ignition of evolved hydrogen [1]. Since air would rapidly be swept from the flask by the gas flow, it seems probable that a hydrogen explosion sufficient to damage the hood would be external to the reaction flask. The desired fluoroalkoxide is undoubtedly thennodynamically imstable with respect to sodium fluoride formation and a number of other metal derivatives of fluorinated organics have proved explosively metastable [2]. 

The standard potential for the anodic reaction is 1.19 V, close to that of 1.228 V for water oxidation. In order to minimize the oxygen production from water oxidation, the cell is operated at a high potential that requires either platinum-coated or lead dioxide anodes. Various mechanisms have been proposed for the formation of perchlorates at the anode, including the discharge of chlorate ion to chlorate radical (87—89), the formation of active oxygen and subsequent formation of perchlorate (90), and the mass-transfer-controUed reaction of chlorate with adsorbed oxygen at the anode (91—93). Sodium dichromate is added to the electrolyte ia platinum anode cells to inhibit the reduction of perchlorates at the cathode. Sodium fluoride is used in the lead dioxide anode cells to improve current efficiency. 

Treatment of glyoxal with sulfur tetrafluoride in the presence of sodium fluoride results iii the formation of difluoroethylene glycol orthosulfite [174] (equation 89) Similarly, perfluonnated 1,2-diketones react with sulfur tetrafluonde to give tetraoxyspirosulfuranes as the only products Thus, perfluorobiacetyl gives a ciystalhne product, perfluorobutylene glycol 2,3 orthosulfite [175] (equation 89)... 

The nucleophilic displacement of halogens by pentafluorophenoxide ion resulted in the formation of the corresponding esters [31] (equation 29) (Table 12). Reactions of trifluoromethanesulfinyl fluoride with fluoro alcohols in the presence of sodium fluoride or cesium fluoride are used to prepare sulfmates [32] (equation 30) (Table 12). 

The acidic conditions of standard SBA-15 synthesis [35] cause the precipitation of metal nanoparticles without silica encapsulation, or the formation of amorphous silica due to the presence of the polymer used for nanoparticle synthesis. Therefore, the SBA-15 framework was synthesized under neutral condition using sodium fluoride as a hydrolysis catalyst and tetramethylorthosilicate (TMOS) as the silica precursor. Pt particles with different sizes were dispersed in the aqueous template polymer solution sodium fluoride and TMOS were added to the reaction mixture. The slurry aged at 313 K for a day, followed by an additional day at 373 K. Pt(X)/SBA-15-NE (X = 1.7, 2.9, 3.6, and 7.1nm) catalysts were obtained by ex-situ calcination (see Section 3.2). TEM images of the ordered... 

Fe. Iron metal was found to be able to mediate the allylation reactions of aryl aldehydes with allyl bromide using sodium fluoride as the promoter. The formation of an allyliron species was proposed as the reactive intermediate in the reaction (Scheme 8.20).187 In view of... 

Palladium-catalyzed hydroarylation of sterically hindered PTAD adduct 157 with aryl halides in the presence of triphenylarsine, sodium acetate, and DMSO provides a 1 1 mixture of 170 and 171. The same reaction done with sodium fluoride and formic acid provides mixtures containing 171 as the major product. Apparently, the use of sodium fluoride as a base allows the selective formation of the opening products 171 in good yields (Equation 19). Similarly, the 2,3-phthalazine-l,4-dione adduct 172 provides the corresponding products 173 and 174 (Equation 20) <2002AGE3375>. 

Sodium fluoride (104) (1-10 mM) inhibits two enzymes of glycolysis the enolase (phosphopyruvate hydratase) and pyruvate kinase. Therefore, aerobic glucose utilization and lactate formation are blocked. 

Polyolefin bottles of suitable size are commercially available. One inconvenience occasionally observed with bottles which have not previously been in contact with hydrogen fluoride is the formation of a slight pink color in the reaction mixture, possibly due to the plasticizers. This coloration does not affect either the yields or the purity of the product, however, because the color is generally eliminated after the product is washed and treated with sodium fluoride. 

Von Runge and Triebs used a solution of dinitrogen pentoxide in chloroform for the N-nitration of both amides and imides. Solutions of dinitrogen pentoxide in chlorinated solvents are not neutral nitrating agents when amides and imides are nitrated - the presence of acidic N-H protons in these substrates leads to the formation of nitric acid. Sodium fluoride acts like a base towards nitric acid and so its addition to these reactions can increase product yield. Sodium acetate has been used for the same purpose during the nitration of n-butyl-V, V -dimethylurea. The effectiveness of dinitrogen pentoxide for the V-nitration of ureas is further illustrated by its use in the conversion of 2-imidazolidinone to N, V -dinitro-2-imidazolidinone in 90 % yield. In the presence of sodium fluoride the yield for this reaction exceeds 90 %. 

Therapy. Formation of new bone matrix is induced by fluoride. Administered as sodium fluoride, it stimulates osteoblasts. Fluoride is substituted for Liillmann, Color Atlas of Pharmacology 2000 Thieme All rights reserved. Usage subject to terms and conditions of license. 

We can use Lewis dot formulas to represent the transfer of electrons in the formation of ionic compounds. For example, the formation of the ionic compound sodium fluoride, NaF, can be represented using Lewis dot formulas and valence electron conflgurations ... 

This calculation is still hypothetical, in that the actual substance formed when sodium metal reacts with difluorine is solid sodium fluoride, and the standard enthalpy of its formation is -569 kJ mol-1. The actual substance is 311 kJ mol-1 more stable than the hypothetical substance consisting of ion pairs, Na+F (g), described above. The added stability of the observed solid compound arises from the long-range interactions of all the positive Na+ ions and negative F ions in the solid lattice which forms the structure of crystalline sodium fluoride. The ionic arrangement is shown in Figure 7.5. Each Na+ ion is octahedrally surrounded (i.e. coordinated) by six fluoride ions, and the fluoride ions are similarly coordinated by six sodium ions. The coordination numbers of both kinds of ion are six. 

It is now possible to produce a theoretical value for the standard enthalpy of formation of sodium fluoride based upon the ionic model described above. The necessary equation is produced by adding together equations 7.1 and 7.3 to give ... 

Figure 7.6 An enthalpy (kJ mol-1) diagram for the formation of the sodium fluoride lattice...

Ionic compounds consist of positive ions (cations) and negative ions (anions) hence, ionic compounds often consist of a metal and nonmetal. The electrostatic attraction between a cation and anion results in an ionic bond that results in compound formation. Binary ionic compounds form from two elements. Sodium chloride (NaCl) and sodium fluoride (NaF) are examples of binary ionic compounds. Three elements can form ternary ionic compounds. Ternary compounds result when polyatomic ions such as carbonate (C032 ), hydroxide (OH-), ammonium (NH4+), form compounds. For example, a calcium ion, Ca2+, combines with the carbonate ion to form the ternary ionic compound calcium carbonate, CaC03. Molecular compounds form discrete molecular units and often consist of a combination of two nonmetals. Compounds such as water (H20), carbon dioxide (C02), and nitric oxide (NO) represent simple binary molecular compounds. Ternary molecular compounds contain three elements. Glucose ( 12 ) is a ternary molecular compound. There are several distinct differences between ionic and molecular compounds, as summarized in Table 1.2. 

M. Amadori studied fused mixtures of sodium fluoride and carbonate no compound is formed, and the salts are not miscible in the solid state. There is a eutectic at 690° and 39 mols. per cent, sodium fluoride. Similar results obtain with sodium chloride and carbonate. There is an eutectic at 636° and 59 mols. per cent, of sodium chloride. Similarly, with potassium fluoride and carbonate, there is with a eutectic at 636° and 65 mols. per cent, of potassium chloride. With the system potassium fluoride and carbonate there is a eutectic at 688° with nearly 46 mols. per cent, of potassium fluoride, and another eutectic at 682° with 62 mols. per cent, of potassium fluoride there is a slight rise in the m.p. between the two eutectics, corresponding with the formation of potassium fluorocarbonate, KF.K2C03. 

Moreover, interesting ring-formation reactions to give 7 have also been reported for substituted mclhoxyallenyl(cyclopropyl)methanols using 70% hydrogen fluoride/pyridine in combination with sodium fluoride or potassium hydrogen fluoride.82... 

Difluorotris(perfluoroalkyl)-25-phosphancs (Rf)3PF2 give stable salts with cesium fluoride, potassium fluoride, sodium fluoride or arenediazonium fluorides, i.e. Cat + [(RF)3PF3] , where Cal+ = Cs +. K+, Na +, ArN2+. The last are difficult to dissolve and they decompose at much lower temperatures (60-90 C) than tetrafluoroborates and hexafluorophosphates. which allows more complete precipitation of diazonium salts from water solutions and their conversion into aryl fluorides 6 without tar formation.6... 

Fluorination of perchloro bis(imine) 4 with sodium fluoride in tetramethylene sulfone at 120 JC takes place with ring formation to give the perfluoro imidazole derivatives 5-7.13... 

The enthalpy of formation of sodium fluoride is —571 kj mol. Estimate the electron affinity of fluorine Compare your value with that giver in Table 23. 

The heat of formation of liquid arsenic trifluoride has been obtained 1 indirectly by determining the heats of dissolution of the trifluoride and of a mixture of arsenious oxide and sodium fluoride in about one litre of normal sodium hydroxide solution. The value obtained was 198,300 calories. Assuming Trouton s constant to be 21, the heat of vaporisation is about -7000 calories, so that the heat of formation of gaseous arsenic trifluoride is 191,300 calories. 

Cyclization products have also been observed when perfluorodienes are heated with fluoride ion. While perfluoropenta-1,4-diene (32) gives perfluoropent-2-yne in 98% yield when passed over cesium fluoride at 240"C, the use of sodium fluoride at 440°C results in the formation of perfluoro(1 -methylcyclobutene) (33) in 58 % yield, together with perfluorocyclopen-tene (10%) and perfluoropent-2-yne (27%).24... 

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