Sodium pentoxide

Disodium phthalocyanine (PcNa2) can be prepared in the same way as the dilithium compound by reacting sodium pentoxide in pentan-l-ol with phthalonitrile. It is more sensitive towards moisture and even alcohol than the dilithium phthalocyanine and is readily demeta-lated.58... 

Relative rate of elimination at 110°C in n-pentanol containing sodium pentoxide. 

At first the unsubstimted metal-free quinoxalinoporphinazine 146 (r1 = r2 = r3 = r4 = e X = HH) was obtained in a 67 % yield by heating dinitiile quinoxaline-2,3-dicarboxylic acid in benzyl alcohol and chlorobenzene at 180 °C with metallic lithium followed by the treatment of the resulting complex with dilute hydrochloric acid (Gal pern and Luk yanets 1969) (Scheme 5.35). A higher yield of 146 (R = R = R = R" = H, X = HH) (95 %) is achieved when carried out in fusion with sodium hydroxide at 220 °C within 15 min (Korzhenevskii et al. 2006). Metal-free benzo[g]quinoxalinoporphinazine 146 (R = R" = H, R, R = Zl, X = HH) obtained from 76d as a result of processing sodium pentoxide and... 

Alkyl halides Aryl halides Anhydrous calcium chloride anhydrous sodium, magnesium or calcium sulphate phosphorus pentoxide. 

Saturated and aromatic hydrocarbons Ethers Anhydrous calcium chloride anhydrous calcium sulphate metallic sodium phosphorus pentoxide. 

Fumaric acid is conveniently prepared by the oxidation of the inexpensive furfural with sodium chlorate in the presence of a vanadium pentoxide catalyst ... 

C. Fumaric acid from furfural. Place in a 1-litre three-necked flask, fitted with a reflux condenser, a mechanical stirrer and a thermometer, 112 5 g. of sodium chlorate, 250 ml. of water and 0 -5 g. of vanadium pentoxide catalyst (1), Set the stirrer in motion, heat the flask on an asbestos-centred wire gauze to 70-75°, and add 4 ml. of 50 g. (43 ml.) of technical furfural. As soon as the vigorous reaction commences (2) bvi not before, add the remainder of the furfural through a dropping funnel, inserted into the top of the condenser by means of a grooved cork, at such a rate that the vigorous reaction is maintained (25-30 minutes). Then heat the reaction mixture at 70-75° for 5-6 hours (3) and allow to stand overnight at the laboratory temperature. Filter the crystalline fumaric acid with suction, and wash it with a little cold water (4). Recrystallise the crude fumaric acid from about 300 ml. of iif-hydrochloric acid, and dry the crystals (26 g.) at 100°. The m.p. in a sealed capillary tube is 282-284°. A further recrystaUisation raises the m.p. to 286-287°. 

The vanadium pentoxide catalyst Is prepared as follows Suspend 5 g. of pure ammonium vanadate in 50 ml. of water and add slowly 7 5 ml. of pure concentrated hydrochloric acid. Allow the reddish-brown, semi-colloidal precipitate to settle (preferably overnight), decant the supernatant solution, and wash the precipitate several times by decantation. Finally, suspend the precipitate in 76 ml. of water and allow it to stand for 3 days. This treatment renders the precipitate granular and easy to 6lter. Filter the precipitate with suction, wash it several times with cold 5 p>er cent, sodium chloride solution to remove hydrochloric acid. Dry the product at 120° for 12 hours, grind it in a mortar to a fine powder, and heat again at 120° for 12 hours. The yield of catalyst is about 3 - 5 g. 

Benzoquinone ( quinone ) is obtained as the end product of the oxidation of aniline by acid dichromate solution. Industrially, the crude product is reduced with sulphur dioxide to hydroquinone, and the latter is oxidised either with dichromate mixture or in very dilute sulphuric acid solution with sodium chlorate in the presence of a little vanadium pentoxide as catalyst. For the preparation in the laboratory, it is best to oxidise the inexpensive hydroquinone with chromic acid or with sodium chlorate in the presence of vanadium pent-oxide. Naphthalene may be converted into 1 4-naphthoquinone by oxidation with chromic acid. 

Place 45 g. of benzamide (Section IV, 188) and 80 g. of phosphorus pentoxide in a 250 ml. Claisen flask (for exact experimeutal details on the handling and weighing out of phosphoric oxide, see under Acetamide, Section 111,111). Mix well. Arrange for distillation (Fig.//, 29, 1 or Fig. II, 20, 1) under reduced pressure use a water pump with an air leak in the system so that a pressure of about 100 mm. is attained. Heat the flask with a free flame until no more liquid distils the nitrile will pass over at 126-130°/100 mm. Wash the distillate with a little sodium carbonate solution, then with water, and dry over anhydrous calcium chloride or magnesium sulphate. Distil under normal pressure (Fig. II, 13, 2 or II, 13, 6) from a 50 ml. flask the benzonitrile passes over as a colourless liquid at 188-189° (compare Section IV,66). The yield is 28 g. 

Table 2. Properties of Antimony Pentoxide and Sodium Antimonate...

Sodium antimonate contains less antimony than either antimony trioxide or pentoxide and is thus less effective. However, its unique pH and low refractive index makes the antimonate the most desirable synergist for polymers that hydrolyze when processed with acidic additives or in polymers for which deep color tones are specified. Sodium antimonate costs approximately 3.30—4.40/kg and can be obtained from either Elf Atochem NA under the Thermoguard name or from Anzon Inc. as a Timinox product. 

Sodium metaniob ate (1 1) [67211-31-8] Na20 Nb20 7H20 or Na2Nb20g-7H20, separates as colorless triclinic crystals as a result of concentrating the mother Hquor from the preparation of the 7 6 sodium niobate by spontaneous evaporation. It also can be obtained by fusion of the anhydrous pentoxide in sodium hydroxide or carbonate. 

Arsenic Peroxides. Arsenic peroxides have not been isolated however, elemental arsenic, and a great variety of arsenic compounds, have been found to be effective catalysts ia the epoxidation of olefins by aqueous hydrogen peroxide. Transient peroxoarsenic compounds are beheved to be iavolved ia these systems. Compounds that act as effective epoxidation catalysts iaclude arsenic trioxide, arsenic pentoxide, arsenious acid, arsenic acid, arsenic trichloride, arsenic oxychloride, triphenyl arsiae, phenylarsonic acid, and the arsenates of sodium, ammonium, and bismuth (56). To avoid having to dispose of the toxic residues of these reactions, the arsenic can be immobi1i2ed on a polystyrene resia (57). 

At room temperature, Htde reaction occurs between carbon dioxide and sodium, but burning sodium reacts vigorously. Under controUed conditions, sodium formate or oxalate may be obtained (8,16). On impact, sodium is reported to react explosively with soHd carbon dioxide. In addition to the carbide-forrning reaction, carbon monoxide reacts with sodium at 250—340°C to yield sodium carbonyl, (NaCO) (39,40). Above 1100°C, the temperature of the DeviHe process, carbon monoxide and sodium do not react. Sodium reacts with nitrous oxide to form sodium oxide and bums in nitric oxide to form a mixture of nitrite and hyponitrite. At low temperature, Hquid nitrogen pentoxide reacts with sodium to produce nitrogen dioxide and sodium nitrate. 

Tantalum. Numerous methods developed to extract tantalum metal from compounds included the reduction of the oxide with carbon or calcium the reduction of the pentachloride with magnesium, sodium, or hydrogen and the thermal dissociation of the pentachloride (30). The only processes that ever achieved commercial significance are the electrochemical reduction of tantalum pentoxide in molten K TaF /KF/KCl mixtures and the reduction of K TaF with sodium. 

The principal vanadium-bearing ores are generally cmshed, ground, screened, and mixed with a sodium salt, eg, NaCl or Na2C02- This mixture is roasted at ca 850°C and the oxides are converted to water-soluble sodium metavanadate, NaVO. The vanadium is extracted by leaching with water and precipitates at pH 2—3 as sodium hexavanadate, Na V O, a red cake, by the addition of sulfuric acid. This is then fused at 700°C to yield a dense black product which is sold as technical-grade vanadium pentoxide. This product contains a minimum of 86 wt % V20 and a maximum of 6—10 wt % Na20. 

For solvent extraction of a tetravalent vanadium oxyvanadium cation, the leach solution is acidified to ca pH 1.6—2.0 by addition of sulfuric acid, and the redox potential is adjusted to —250 mV by heating and reaction with iron powder. Vanadium is extracted from the blue solution in ca six countercurrent mixer—settler stages by a kerosene solution of 5—6 wt % di-2-ethyIhexyl phosphoric acid (EHPA) and 3 wt % tributyl phosphate (TBP). The organic solvent is stripped by a 15 wt % sulfuric acid solution. The rich strip Hquor containing ca 50—65 g V20 /L is oxidized batchwise initially at pH 0.3 by addition of sodium chlorate then it is heated to 70°C and agitated during the addition of NH to raise the pH to 0.6. Vanadium pentoxide of 98—99% grade precipitates, is removed by filtration, and then is fused and flaked. 

For vanadium solvent extraction, Hon powder can be added to reduce pentavalent vanadium to quadrivalent and trivalent Hon to divalent at a redox potential of —150 mV. The pH is adjusted to 2 by addition of NH, and an oxyvanadium cation is extracted in four countercurrent stages of mixer—settlers by a diesel oil solution of EHPA. Vanadium is stripped from the organic solvent with a 15 wt % sulfuric acid solution in four countercurrent stages. Addition of NH, steam, and sodium chlorate to the strip Hquor results in the precipitation of vanadium oxides, which are filtered, dried, fused, and flaked (22). Vanadium can also be extracted from oxidized uranium raffinate by solvent extraction with a tertiary amine, and ammonium metavanadate is produced from the soda-ash strip Hquor. Fused and flaked pentoxide is made from the ammonium metavanadate (23). 

Minor uses of vanadium chemicals are preparation of vanadium metal from refined pentoxide or vanadium tetrachloride Hquid-phase organic oxidation reactions, eg, production of aniline black dyes for textile use and printing inks color modifiers in mercury-vapor lamps vanadyl fatty acids as driers in paints and varnish and ammonium or sodium vanadates as corrosion inhibitors in flue-gas scmbbers. 

Antimony Compounds. The greatest use of antimony compounds is in flame retardants (qv) for plastics, paints, textiles, and mbber. Antimony compounds used in flame retardants are antimony pentoxide, sodium antimonate [15593-75-6] Na[Sb(OH) ], and, most importantly, antimony trioxide. These compounds, when used alone, are poor flame retardants however, when combined with halogen compounds, they produce mixtures that are effective. 

A number of complex derivatives of antimony pentoxide with polyhydroxy compounds have been iavestigated as dmgs. The most important of these substances is known as antimony sodium gluconate [16037-91-5] C22H2Q02ySb2 9H20 3Na, which is prepared by the reaction of antimony pentoxide, gluconic acid, and sodium hydroxide (53). 

The active phase, which is soHd at room temperature, is comprised of mixed potassium and sodium vanadates and pyrosulfates, whereas the support is macroporous siUca, usually in the form of 6—12 mm diameter rings or pellets. The patent Hterature describes a number of ways to prepare the catalyst a typical example contains 7 wt % vanadium pentoxide, 8% potassium added as potassium hydroxide or carbonate, 1% sodium, and 78 wt % siUca, added as diatomaceous earth or siUca gel, formed into rings, and calcined in the presence of sulfur dioxide or sulfur trioxide to convert a portion of the alkah metal salts into various pyrosulfates (81,82). 

However, this method is appHed only when esterification cannot be effected by the usual acid—alcohol reaction because of the higher cost of the anhydrides. The production of cellulose acetate (see Fibers, cellulose esters), phenyl acetate (used in acetaminophen production), and aspirin (acetylsahcyhc acid) (see Salicylic acid) are examples of the large-scale use of acetic anhydride. The speed of acylation is greatiy increased by the use of catalysts (68) such as sulfuric acid, perchloric acid, trifluoroacetic acid, phosphoms pentoxide, 2inc chloride, ferric chloride, sodium acetate, and tertiary amines, eg, 4-dimethylaminopyridine. 

Calcium chloride, calcium sulfate, magnesium sulfate, phosphorus pentoxide, sodium sulfate. 

Magnesium sulfate, potassium carbonate, sodium hydroxide. Calcium chloride, c cium sulfate, magnesium sulfate, phosphorus pentoxide, sodium (not for olefins). 

Dimethoxyethane and triethylamine, both in zur Synthese quality, were purchased from E. Merck, Darmstadt. Diethyl ether was distilled from phosphorus pentoxide and stored over sodium wire. 

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