Bismuth treatment

Aniline and Formaldehyde. Explosive resin formed from mixture.8 Antimony or Bismuth. Treatment of antimony (III)10 compounds or bismuth11 can be very hazardous. 

MAA and MMA may also be prepared via the ammoxidation of isobutylene to give meth acrylonitrile as the key intermediate. A mixture of isobutjiene, ammonia, and air are passed over a complex mixed metal oxide catalyst at elevated temperatures to give a 70—80% yield of methacrylonitrile. Suitable catalysts often include mixtures of molybdenum, bismuth, iron, and antimony, in addition to a noble metal (131—133). The meth acrylonitrile formed may then be hydrolyzed to methacrjiamide by treatment with one equivalent of sulfuric acid. The methacrjiamide can be esterified to MMA or hydrolyzed to MAA under conditions similar to those employed in the ACH process. The relatively modest yields obtainable in the ammoxidation reaction and the generation of a considerable acid waste stream combine to make this process economically less desirable than the ACH or C-4 oxidation to methacrolein processes. 

Other methods for safely cleaning apparatus containing sodium residues or disposing of waste sodium are based on treatment with bismuth or lead (103), inert organic Hquids (104—106), or by reaction with water vapor carried in an inert gas stream (107). 

Catalytic Oxidation. Catalytic oxidation is used only for gaseous streams because combustion reactions take place on the surface of the catalyst which otherwise would be covered by soHd material. Common catalysts are palladium [7440-05-3] and platinum [7440-06-4]. Because of the catalytic boost, operating temperatures and residence times are much lower which reduce operating costs. Catalysts in any treatment system are susceptible to poisoning (masking of or interference with the active sites). Catalysts can be poisoned or deactivated by sulfur, bismuth [7440-69-9] phosphoms [7723-14-0] arsenic, antimony, mercury, lead, zinc, tin [7440-31-5] or halogens (notably chlorine) platinum catalysts can tolerate sulfur compounds, but can be poisoned by chlorine. 

The existence of bismuthine was first demonstrated by using a radioactive tracer, Bi (8). Acid treatment of a magnesium plate coated with Bi resulted in the hberation of a volatile radioactive compound. In subsequent experiments, magnesium bismuthide [12048-46-3], Mg Bi, was treated with acid the yield, however, was only one part of bismuthine for every 20,000 parts of bismuth dissolved. Attempts to prepare bismuthine by reduction of bismuth trichloride with a borohydride have not been particularly successful. Experimental quantities ate best prepared by disproportionation of either methylbismuthine [66172-95-0], CH Bi, or dimethylbismuthine [14381-45-4], C2H. Bi (7) ... 

Bismuth triduoride is usually prepared by dissolving either Bi O or BiOF in hydroduoric acid to yield the addition compound bismuth triduoride ttihydroduoride [66184-11-0] 3 HF or H2(BiF ). Caredil evaporation of the solution permits isolation of a grey soHd, which upon heating loses HF to yield BiF. It may be purified by sublimation in a stream of HF at 500°C. Bismuth triduoride may also be prepared by direct duorination of bismuth by (/) reaction of Bi O with sulfiir tetraduoride, SF (2) treatment of metallic bismuth with HF at 350°C and (J) reduction of BiF in a dilute stream of hydrogen. 

Bismuth Triperchlorate Pentahydrate. Bismuth(III) perchlorate pentahydrate [66172-92-7], Bi(C10 2 5H20, is prepared by dissolving Bi202 in 70% HCIO4. Anhydrous bismuth triperchlorate [14059-45-1], Bi(C10 2> maybe prepared by heating bismuthyl perchlorate monohydrate [66172-93-8], BiOClO H2O, between 80 and 100°C. Attempts to dissolve bismuth metal in concentrated perchloric acid have resulted in explosions. Treatment of bismuth or with dilute solutions of perchloric acid yields hydrates of bismuthyl perchlorate. 

Bismuth compounds were once employed for the treatment of amoebic dysentery, certain skin diseases, and several spirochetal diseases besides syphilis, but these substances are now seldom considered the dmgs of choice. Various insoluble preparations of bismuth, especially the subcarbonate, subnitrate, subgaHate, subcitrate, and subsahcylate, are stiU employed for the treatment of ulcers and other gastrointestinal disorders, even though use for these purposes is often supported largely by tradition. With a few possible exceptions, it is now difficult to justify the presence of bismuth compounds in a modem therapeutic armamentarium. A review of the biological activity of organobismuth compounds has been pubHshed (179). 

Bismuth subsahcylate [14882-18-9] Pepto-Bismol, is a basic salt of varying composition, corresponding approximately to i9-H0CgH4C02(Bi0). Like a number of other insoluble bismuth preparations, it is not currentiy approved in the United States for the treatment of peptic ulcer disease but is under active investigation for this purpose (180). It does appear to be effective for the rehef of mild diarrhea and for the prevention of travelers diarrhea (181). The ready availabiUty of this dmg, however, may lead to its ovemse and result in toxic effects caused by both the saUcylate and bismuth components. It has been suggested that bismuth subsahcylate is somewhat effective in the symptomatic treatment of isosporiasis, a disease caused by the intracellular parasite Isospora belli (182). 

Tripotassium dicitratobismuthate [57644-54-9] (bismuth subcitrate), De-Nol is a buffered aqueous suspension of a poorly defined, water-insoluble bismuth compound. It is said to very effective for the treatment of gastric and duodenal ulcers (180,184). There have not yet been any reports of bismuth encephalopathy following the use of this dmg. 

Bismuth subgaHate [12552-60-2] (basic bismuth gaHate), Dermatol, is a bright yellow powder that can be prepared by the interaction of bismuth nitrate and gaUic acid in an acetic acid medium. It has been employed as a dusting powder in some skin disorders and as an ingredient of suppositories for the treatment of hemorrhoids (183,185). It has been taken orally for many years by colostomy patients in order to control fecal odors, but the dmg may cause serious neurological problems (186). 

The precipitated copper from this reaction is an important constituent of the slime that collects at the bottom of the electrolytic cells. The accumulation of copper as well as of impurities such as nickel, arsenic, antimony, and bismuth is controlled by periodic bleed-off and treatment in the electrolyte purification section. 

Tia, as well as some other metals, can undergo a phenomenon where tiny metal filaments, called whiskers, form randomly on parts used ia electrical apphcafions. In low voltage, miniature circuitry, whiskers can cause short circuits. Alloys having 2% lead minimum or 0.5% bismuth or heat treatments are said to overcome the problem. A specification for electroplated fin coafings is available (133). 

Copper (II), Bismuth (III) and lead (II), ai e important elements in the environment and they have essential roles in different biologieal systems. Lead is widely distributed in nature and exhibits severe deleterious effeets on human [1]. Copper is an essential element for the normal metabolism of many living organisms. Bismuth has been used in medieines for the treatment of helieobaeter pylorie-indueed gastritis [2, 3]. Therefore traee analysis of these elements is important for monitoring their eoneentration in the environment. 

As described earlier one of the possible products from the AFO reaction is dihydroxyflavonols. Simpson and coworkers took advantage of this outcome in their synthesis of the flavonol rhamnocitrin (23). Chalcone 24 was subjected to the typical AFO conditions to deliver dihydroxyflavonol 25. The isolated product was further subjected to hydrogen peroxide to afford flavonol 25a in 30% yield. However, treatment of 25 with bismuth acetate, generated in situ from bismuth carbonate and acetic acid, gave 25a in 77% yield for a respectable 52% overall yield over two steps. 25a was then selectively demethylated with anilinium chloride to deliver rhamnocitrin (23). 

Cations forming insoluble chromates, such as those of silver, barium, mercury (I), mercury(II), and bismuth, do not interfere because the acidity is sufficiently high to prevent their precipitation. Bromide ion from the generation may be expected to form insoluble silver bromide, and so it is preferable to separate silver prior to the precipitation. Ammonium salts interfere, owing to competitive oxidation by bromate, and should be removed by treatment with sodium hydroxide. 

The reaction is a sensitive one, but is subject to a number of interferences. The solution must be free from large amounts of lead, thallium (I), copper, tin, arsenic, antimony, gold, silver, platinum, and palladium, and from elements in sufficient quantity to colour the solution, e.g. nickel. Metals giving insoluble iodides must be absent, or present in amounts not yielding a precipitate. Substances which liberate iodine from potassium iodide interfere, for example iron(III) the latter should be reduced with sulphurous acid and the excess of gas boiled off, or by a 30 per cent solution of hypophosphorous acid. Chloride ion reduces the intensity of the bismuth colour. Separation of bismuth from copper can be effected by extraction of the bismuth as dithizonate by treatment in ammoniacal potassium cyanide solution with a 0.1 per cent solution of dithizone in chloroform if lead is present, shaking of the chloroform solution of lead and bismuth dithizonates with a buffer solution of pH 3.4 results in the lead alone passing into the aqueous phase. The bismuth complex is soluble in a pentan-l-ol-ethyl acetate mixture, and this fact can be utilised for the determination in the presence of coloured ions, such as nickel, cobalt, chromium, and uranium. 

Platinum catalysts were prepared by ion-exchange of activated charcoal. A powdered support was used for batch experiments (CECA SOS) and a granular form (Norit Rox 0.8) was employed in the continuous reactor. Oxidised sites on the surface of the support were created by treatment with aqueous sodium hypochlorite (3%) and ion-exchange of the associated protons with Pt(NH3)42+ ions was performed as described previously [13,14]. The palladium catalyst mentioned in section 3.1 was prepared by impregnation, as described in [8]. Bimetallic PtBi/C catalysts were prepared by two methods (1) bismuth was deposited onto a platinum catalyst, previously prepared by the exchange method outlined above, using the surface redox reaction ... 

A 15% nitric acid solution in ethanol was used to clean a bismuth crystal. The solution decomposed violently after this treatment and projected the content of the container into the extraction hood in which it was placed. Mixtures with less than 10% of nitric acid in alcohol are the only ones to remain stable for short periods of time. They should never be stored. In this particular accident, the presence of bismuth suggests a reaction of type (3). 

Refining operations have two principal wastestreams, waste electrolyte and cathode and anode washwater. Spent electrolyte is normally recycled. A bleed stream is treated to reduce copper and impurity concentration. Varying degrees of treatment are necessary because of the differences in the anode copper. Anode impurities, including nickel, arsenic, and traces of antimony and bismuth, may be present in the effluent if the spent electrolyte bleed stream is discharged. Tables 3.14 and 3.15 present classical and toxic pollutant data for raw wastewater in this subcategory. 

Bertrand and co-workers synthesized compound 310 in good yield (90%) by the treatment of a toluene solution of 311 with BiCls at — 78 °C. The coordination geometry around the bismuth center was found to be nearly trigonal bipyr-amidal. The reactivity of compound 310 toward various Lewis acids was studied. Transmetallation occurs with both... 

The work in this group has focussed mainly in antimony and bismuth because of the thermoelectric properties of the chalcogenides186 and as low temperature single-source precursors to related semiconductor materials.187 The use of bismuth compounds in the treatment of gastrointestinal disorders has lead to the study of several thiolate compounds as models to understand the bioactivity. 

Only chromium (III) co-precipitates quantitatively with hydrated iron (III) oxide at the pH of seawater, around 8. In order to collect chromium (VI) directly without pre-treatment, e.g., reduction to chromium (III), hydrated bismuth oxide, which forms an insoluble compound with chromium (VI) was used. Chromium (III) is collected with hydrated bismuth oxide (50 mg per 400 ml seawater). Chromium (VI) in seawater is collected at about pH 4 and chromium (VI) is collected below pH 10. Thus both chromium (III) and chromium (VI) are collected quantitatively at the pH of seawater, i.e., around 8. 

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