Bismuth trioxide

A solution of bismuth trioxide in hot glacial acetic acid provides a specific method for the oxidation of acyloins. The reaction rate is dependent on the steric accessibility of the ketol system. A 2,3-ketol requires less than one hour for completion but an 11,12-ketol is not yet fully oxidized in thirty hours. The reaction is highly selective as a-keto acids, hydrazines and phenols are not oxidized. In a direct comparison with cupric acetate, this procedure is somewhat superior for the preparation of a 2,3-diketone from a 2-keto-3-hydroxy steroid.  

Acknowledgment The authors wish to express their gratitude to Dr. J. Edwards of Syntex Research who provided the experimental procedure utilizing silver carbonate on Celite. We are also indebted to the Synthetic Chemical Research Department of Merck Sharp Dohme Research Laboratories for providing time to complete this review and also to Miss Joanna Mohr for her patience and care in preparing the manuscript. 

TABLE 5-2 Compatibility of Functional Groups to Various Oxidants 

Functionality H2Cr04 acetone CrOs, aq. acetic acid CrOs pyridine NBA r-butanol DMSO DCC Oppenauer DDQ MnOa Pb(0Ac)4 pyridine 

C-compatible under normal conditions N-not compatible under normal conditions 

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Complexes of BiF are almost unknown, but crystaUi2ation from a hot solution of ammonium duoride that has been saturated with freshly precipitated bismuth trioxide yields crystals of ammonium tetraduorobismuthate(III) [13600-76-5] NH BiF. This complex is readily decomposed by water. 

Bismuth Oxides and Bismuthates. The only oxide of bismuth that has been definitely isolated in a pure state is bismuth trioxide. An acidic oxide that approximates the composition Bi20 certainly exists. However, there is considerable question as to the exact nature of this material and the species involved. A number of other oxides have been reported, eg, bismuth oxide (1 1) [1332-64-5], bismuth oxide (1 2), bismuth oxide (2 4)... 

Bismuth Trioxide. Bismuth(Ill) oxide [1304-76-3] has a compHcated polymorphism. At times some of the reported phases deviate from Bi202 by baying too Htfle or too much oxygen at least in one instance, because of the ready contamination of Bi202 melts with siHcon, the reported phase... 

Bismuth trioxide may be prepared by the following methods (/) the oxidation of bismuth metal by oxygen at temperatures between 750 and 800°C (2) the thermal decomposition of compounds such as the basic carbonate, the carbonate, or the nitrate (700—800°C) (J) precipitation of hydrated bismuth trioxide upon addition of an alkah metal hydroxide to a solution of a bismuth salt and removal of the water by ignition. The gelatinous precipitate initially formed becomes crystalline on standing it has been represented by the formula Bi(OH)2 and called bismuth hydroxide [10361 -43-0]. However, no definite compound has been isolated. 

Bismuth trioxide is practically insoluble in water it is definitely a basic oxide and hence dissolves in acids to form salts. Acidic properties are just barely detectable, eg, its solubiUty slightly increases with increasing base concentration, presumably because of the formation of bismuthate(III) ions, such as Bi(OH) g and related species. 

Bismuth trioxide forms numerous, complex, mixed oxides of varying composition when fused with CaO, SrO, BaO, and PbO. If high purity bismuth, lead, and copper oxides and strontium and calcium carbonates are mixed together with metal ratios Bi Pb Sn Ca Cu = 1.9 0.4 2 2 3 or 1.95 0.6 2 2 3 and calcined at 800—835°C, the resulting materials have the nominal composition Bi PbQ4Sr2Ca2Cu20 and Bi 25PbQgSr2Ca2Cu20 and become superconducting at about 110 K (25). 

Bismuth Salts. Bismuth trioxide dissolves in concentrated solutions of strong oxyacids to yield bismuth salts. In more dilute solutions of strong acids or in solutions of weak acids, the oxide reacts to form bismuthyl or basic salts. The normal salts are very susceptible to hydrolysis. 

Bismuth ligands, 2,989-1061 bonding, 2,1030-1041 7i bonding, 2, 1033-1039 trigonal bipyramidal complexes, 2,1036 Bismuth line, 3,294 Bismuthotungstates, 3, 1042 Bismuth pentafluoride, 3, 292 Bismuth tribromide, 3, 291 Bismuth trichloride, 3, 290 Bismuth trifiuoride, 3, 290 Bismuth triiodide, 3,292 Bismuth trioxide, 3,284 2,2 -Bisphenol metal complexes color photography, 6,109 Bis(trimethylene)triamine metal complexes, 2, 49 4,4 -Bi-l, 2,4-triazolyl metal complexes, 2, 89 polymers... 

Bismuth trioxide incandesces with sodium or potassium. Bismuth halogens (chlorinated, brominated, iodated) detonate in contact with potassium. 

Aluminium oxide, arsenic trioxide, bismuth trioxide, calcium oxide, chromic oxide, lanthanum oxide, lead dioxide, magnesium oxide, manganese dioxide, molybdenum trioxide, phosphorus pentoxide, stannic oxide, sulfur dioxide (explodes), tantalum pentoxide, tungsten trioxide, vanadium pentoxide. 

Lead peroxide reacts explosively [1] and copper(II) oxide incandescently [2] with warm potassium. Mercury(II) and (I) oxides react with molten potassium with incandescence and explosion, respectively [3], Tin(IV) oxide is reduced incandescently on warming [4] and molybdenum(III) oxide on heating [5], Warm bismuth trioxide is reduced with incandescence [6],... 

All of the organohalogen compounds studied were commercial products obtained from various manufacturers and used as received. Only the DBDPO was purified further by recrystallization for some of the chromatography and thermal analysis experiments. Samples of antimony trioxide and antimony pentoxide were also obtained from commercial sources. The ultrapure antimony trioxide, bismuth trioxide, bismuth metal, antimony metal, dibenzofuran and diphenyl ether were all obtained from Aldrich Chemicals. The poly(propylene) (PP) resin was 0.7 mfi, food grade from Novamont and the poly(ethylene) was unstabilized, high molecular weight, HDPE from American Hoechst. 

The third class, Class III, contained those mixtures exhibiting the greatest extent of reaction. Included in this class were Sb203, Sb°(metal), Bi°(metal), bismuth trioxide (B i 2 0 3) and antimony trisulfide (Sb2S3). These data are summarized and compared to those from the simple PP/DBDPO mixture in Table VII. 

Bismuth salts, 4 25 Bismuth sesquisulfide, 4 24 Bismuth subcarbonate, 4 36 Bismuth subgallate, 4 36 Bismuth subhalides, 4 19 Bismuth subnitrate, 4 36 Bismuth subsalicylate, 4 1, 36 medical applications of, 22 11-12 Bismuth(III) sulfate, 4 25 Bismuth(III) sulfide, 4 24 Bismuth sulfides, 4 24-25 Bismuth thiolates, 4 25 Bismuth-tin alloy waterfowl shot, 4 15 Bismuth triacetate, 4 25 Bismuth tribromide, 4 21 physical properties of, 4 20t Bismuth trichloride, 4 19-20 physical properties of, 4 20t Bismuth trifluoride, 4 19 physical properties of, 4 20t Bismuth trihalides, 4 19 Bismuth triiodide, 4 21-22 physical properties of, 4 20t Bismuth trinitrate pentahydrate, 4 25 Bismuth trioxide, 4 23-24 physical properties of, 4 20t Bismuth triperchlorate pentahydrate, 4 25... 

Bismuth is stable to both dry and moist air at ordinary temperatures. At elevated temperatures, the vapors of the metal combine rapidly with oxygen, forming bismuth trioxide, Bi203. The element dissolves in concentrated nitric acid forming bismuth nitrate pentahydrate, Bi(N03)3 5H20. Addition of water to this salt solution precipitates an oxysalt, Bi203N205 2H20. Reaction with hydrochloric acid followed by evaporation of the solution produces bismuth trichloride, BiCB. 

Thermal dissociation gives bismuth trioxide and dinitrogen pentoxide ... 

Bismuth trioxide occurs in nature as mineral bismite. The oxide is used in fireproofing of papers and polymers in enameling cast iron ceramic and in disinfectants. 

Bismuth trioxide is commercially made from bismuth subnitrate. The latter is produced by dissolving bismuth in hot nitric acid. Addition of excess sodium hydroxide followed by continuous heating of the mixture precipitates bismuth trioxide as a heavy yellow powder. Also, the trioxide can be prepared by ignition of bismuth hydroxide. 

Electrolysis of bismuth trioxide in hot concentrated alkali solution gives a scarlet red precipitate of bismuth pentoxide, Bi205. 

Bismuth trioxide reacts with hydrofluoric acid forming bismuth trifluoride, BiFs. 

Neidert, J.B., and Askins, R.E. (1994) Bum rate modification of solid propellants with bismuth trioxide. U S Patent 5,372,070. 

Direct halogenation of metallic bismuth yields bismuth pentafluoride in the case of fluorine, the corresponding bismuth trihalides for the other halogens. Reaction of bismuth trioxide with aqueous HF, HC1, or HBr yields the corresponding bismuth trihalide. Physical and thermochemical properties of the more important bismuth halides appear in Table 2. 

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