Transfer nitration alcohols

We also found N-nitropyridinium salts such as C5HjN N02BF4 as convenient transfer nitrating reagents in selective, clean reaetions. Transfer nitrations are equally applicable to C- as well as to 0-nitra-tions, allowing, for example, safe, acid-free preparation of alkyl nitrates and polynitrates from alcohols (including nitroglycerine). 

Olah and co-workers ° conducted a comprehensive study into the use of N-nitropyridinium salts for nitration. Such salts are easily prepared from the slow addition of the appropriate heterocyclic base to an equimolar suspension of nitronium tetrafluoroborate in acetonitrile. Olah studied the effect on nitration of changing both the structure of the heterocyclic base and the counter ion. Three of these salts (20, 21, 22) illustrated above have been synthesized and used for the 0-nitration of alcohols with success. Transfer nitrations with Al-nitropyridinium salts are particularly useful for the preparation of nitrate esters from acid-sensitive alcohols and polyols because conditions are essentially neutral. 

Transfer, nitration of alcohols with nitro-collodiniurr. tctrafluoroboratc see NitrocolUMlintum tctrafluoroboratc Transmission of dc tonation see Gap test... 

Nitrocollodinium tciranuort>buraie, transfer nitration of alcohols with 291 Nitrocompounds as explosives (IT88) biological activity of 90 infra-red and Raman spccir[Pg.683]

Alkyl nitrates must be prepared and stored with care, as particularly in the presence of even traces of adds they can become explosive [15]. They should not be stored over prolonged periods of times. This is particularly the case for nitrates of polyols. The simplest and effective means of their preparation involves reaction of alcohols with nitronium salts in the presence of an acid-binding agent. Transfer nitrations with. -nitropyridinium salts are particularly suited for their acid-free preparation [16],... 

The method was further improved using N-nitrocoIlidinium tetra-fluoroborate as transfer nitrating agent for alcohols (polyols) [73]. 

Alcohols undergo transfer nitration with N-nitrocollidinium tetra-fluoroborate under essentially neutral conditions. Yields were found to be close to quantitative. Separation of alkyl nitrates by distillation or crystallization gave good-to-excellent preparative yields (Table XXVII),... 

The nitrate esters are formed with retention of configuration in contrast to the reaction of silver nitrate with alkyl halides. Furthermore, the reac-tion of benzyl alcohol shows that 0-nitration of alkylary] alcohols in transfer nitration is preferred to aromatic Onitration. 

N-Nitrocollidinium tetrafluoroborate (85), a new safe and mild reagent for the transfer nitration of alcohols (Scheme 48), is less reactive than nitronium tetrafluoroborate but allows better controlled conditions and superior yields. The O-nitration of arylalkyl alcohols is preferred to aromatic C-nitration. 

I he methyl iodide is transferred quantitatively (by means of a stream of a carrier gas such as carbon dioxide) to an absorption vessel where it either reacts with alcoholic silver nitrate solution and is finally estimated gravimetrically as Agl, or it is absorbed in an acetic acid solution containing bromine. In the latter case, iodine monobromide is first formed, further oxidation yielding iodic acid, which on subsequent treatment with acid KI solution liberates iodine which is finally estimated with thiosulphate (c/. p. 501). The advantage of this latter method is that six times the original quantity of iodine is finally liberated. 

Urine (2 1.) in a porcelain basin is evaporated to a syrup on the water bath. The flame is extinguished and the hot syrup is stirred with 500 c.c. of alcohol. After some time the clear extract is decanted and the residue is again warmed and once more digested in the same way with 500 c.c. of alcohol. If necessary, the combined extracts are filtered, most of the alcohol they contain is removed by distillation, and the aqueous-alcoholic residue, after transference to a small porcelain basin, is evaporated to dryness on the water bath. The dry residue is well cooled and is kept in an efficient freezing mixture while two volumes of colourless concentrated nitric acid are slowly added with thorough stirring. After the product has stood for twelve hours, the paste of urea nitrate is filtered dry at the pump, washed with a little ice-cold nitric acid (1 1), again filtered with suction till no more liquid drains off, and suspended in 100-150 c.c. of warm water. To this suspension barium carbonate is added... 

The lead picrate for this purpose was produced in the following way [42]. Into a stainless-steel reactor equipped with a stirrer of the type used for the manufacture of lead azide and other initiators (cf. Fig. 49) 8 1. of a solution containing 1.44 kg of lead nitrate and 151. of ice water were poured. Fifteen litres of a solution containing 1.5 kg of picric acid were then added. During the reaction the temperature should be maintained between 6 and 10°C. Since the temperature rises with the precipitation of lead picrate, 7-8 more litres of ice water must be poured into the reactor, usually a few minutes after the picrate has begun to precipitate. After 4 hr the liquid was decanted from above the precipitate the latter was transferred to a cloth filter and washed with alcohol (101.) to which an aqueous solution of lead, nitrate (500 ml of a 30% solution) has been added to avoid the dissolution of lead picrate during washing. 2.2 kg of product was obtainable from one batch. 

The Carius method can also be adapted for the estimation of selenium in organic compounds.8 About 0-2 gram of the substance is treated with nitric acid (sp. gr.=l-4) and about 0-5 gram of silver nitrate. The contents of the tube are transferred to a basin, evaporated to dryness, washed with alcohol and then dissolved in 20 per cent, nitric acid. 

Several compounds of tungsten, which is a transition metal closely related to molybdenum, are able to catalyze the selective oxidation of secondary alcohols with hydrogen peroxide as secondary oxidant. These include tris(cetylpyridinium) 12-tungstophosphate,33 peroxotungstopho-sphate (PCWP)34 and Na2W04 in the presence of a phase transfer catalyst.35 Tungstophosphoric acid is able to catalyze the selective oxidation of secondary alcohols in the presence of ferric nitrate as secondary oxidant.36... 

A copper-chromium oxide on pumice catalyst has particular value for the dehydrogenation of primary and secondary alcohols to the corresponding carbonyl compounds (see Section 5.6.1, p. 581). Dissolve 10.4g of barium nitrate (AnalaR) in 280 ml of water at about 80 °C and add to this hot solution 87 g of copper(n) nitrate trihydrate (AnalaR) stir the mixture and heat until a homogeneous solution results. Prepare a solution of 50.4 g of recrystallised ammonium dichromate in a mixture of 200 ml of water and 75 ml of concentrated ammonia solution (d 0.880). To the ammonium chromate solution at 25-30 °C add the hot (80 °C) nitrate solution in a thin stream with stirring. Allow the mixture to cool and filter off the yellowish-brown precipitate with suction press with a glass stopper and suck as dry as possbile. Transfer the... 

DCE diluent. However, the differences between the stronger fluorinated modifiers and the weaker nonfluorinated modifiers are much more pronounced. This could be due to the fact that the stronger modifiers may be sufficiently acidic to be partly deprotonated when contacted with the alkaline simulant. The alkoxide form of the alcohol would serve as the counteranion to the extracted cesium, eliminating the need for an anion from the aqueous phase (e.g., nitrate) to be coextracted, and, in turn, making it energetically easier to transfer the cesium cation to the solvent phase, hence increasing the cesium distribution ratio. 

Alcoholysis of l-chloro-2,4-dinitrobenzene to 2,4-dinitroanisole. To 800 kg of methyl alcohol in the reactor 196 kg of sodium hydroxide and 600 kg of chloro-dinitrobenzene are added in 10 equal portions. The reagents are added alternately. During this operation, which requires 7 hr, a temperature at 40-45°C is maintained. Then the temperature is raised to 50°C by heating the reactor jacket and kept there for 30 min, before cooling the whole mixture to 35°C (which takes 3 hr). The crystals of the product together with the mother liquor are then transferred to a vacuum filter for separation. The product obtained is washed four times with water, centrifuged and finally transferred to the nitration plant. 

A solution of 350 grams of lead nitrate in 1 liter hot water is treated carefully at 95°C. with about 120 grams of soda ash and the precipitated basic lead carbonate is washed thoroughly with water. The moist material is transferred to a 2-liter flask fitted with stirrer and reflux condenser (Fig. 6) and mixed to a homogeneous paste with 600 grams of 90 per cent alcohol. One mole (228 grams) of very finely pulverized thiocarbanilide is added rapidly, followed by the addition, at 25°, of 1.3 moles of sodium cyanide (about 60 grams of technical material). ... 

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