Oxidation with sulfur dioxide

Photolysis of SOj in the presence of CjF at room temperature with 313 nm radiation gave COFj, C3F5 (13.3), and polymer. For all experiments with C F, pressures above 

10 Synthesis of carbonyl difluoride from other halogenated hydrocarbons 

Carbonyl difluoride is formed frequently during the oxidation of many fluorine-containing halocarbons. The simplest fluorocarbon, CFj (prepared from the decomposition of trifluoromethyl fluorophosphoranes), when generated at 100 C in the presence of Oj, gives COFj [1299]. 

With OPF3, CFj reacts either as a reducing agent or a fluorinating agent. Equations (13.7) or (13.8), respectively. At 100 C, reaction (13.7) accounts for 95 % of the 

Breakage of the P-O bond or the P-C bond in the cyclic intermediate (above) leads to reaction (13.7), whereas reaction (13.8) requires a series of fluorine shifts from the carbon to the phosphorus atom, to give CO and PF [1300]. 

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The 4,5-unsubstituted 1,3,2-dioxathiolane system (7) exists only in the form of its 2-oxide and 2,2-dioxide or their derivatives. 1,3,2-Dioxathiolane 2-oxide (16) represents the parent compound of saturated five-membered cyclic sulfites. It is a colorless, distillable liquid which can be prepared according to the methods shown in Scheme 9. The most convenient laboratory technique is the reaction of ethylene glycol with thionyl chloride <66HC(2l-l)l>. Another possibility is the transesterification of dimethyl sulfite with ethylene glycol (76CRV747). The reaction of ethylene oxide with sulfur dioxide, frequently described in the patent literature (66HC(2l-l)i>, depends on the reaction conditions. It leads either directly... 

Derivation Reduction of telluric oxide with sulfur dioxide by dissolving the oxide in a caustic soda solution and plating out the metal. 

Ramachandran and Smith obtained satisfactory agreement with experimental results on the reduction of nickel oxide with carbon monoxide (pore opening case) by considering the product layer diffusion coefficient as an adjustable parameter. Similarly, the model predicted pore closure and reaction die-off for the reaction of calcium oxide with sulfur dioxide, where the molar volume of calcium sulfate product is about three times that of the calcium oxide reactant. 

Noncombustible gas. Sulfur dioxide reacts violently with alkali metals at their melting points. Reactions with finely divided metals produce incandescence. Explosion occurs when it is mixed with fluorine or interhalogen compounds of fluorine. Incandescence occurs when carbides of alkali metals are placed in a sulfur dioxide atmosphere or by heating metal oxides with sulfur dioxide. An alcoholic or ethereal solution of sulfur dioxide explodes when mixed with powdered potassium chlorate (Mellor 1946). The dry gas reacts with chlorates to form chlorine dioxide, which ignites and explodes on heating. 

Calculate AH for the reaction of sodium oxide with sulfur dioxide ... 

Adams CR, Jennings TJ (1970) Catalytic oxidations with sulfur dioxide II. Alkylaromatics. J Catal 17 157-177... 

Marsh, D.W. and Ulrichson, D.L. (1985) "Rate and diffiisional study of the reaction of calcium oxide with sulfur dioxide", Chem. Eng. Sci., 40, 423-433. 

Sulfur combines direcdy and usually energetically with almost all of the elements. Exceptions include gold, platinum, iridium, and the hehum-group gases (19). In the presence of oxygen or dry air, sulfur is very slowly oxidized to sulfur dioxide. When burned in air, it forms predominantly sulfur dioxide with small amounts of sulfur trioxide. When burned in the presence of moist air, sulfurous acid and sulfuric acids are slowly generated. 

Oxidation of sulfur dioxide in aqueous solution, as in clouds, can be catalyzed synergistically by iron and manganese (225). Ammonia can be used to scmb sulfur dioxide from gas streams in the presence of air. The product is largely ammonium sulfate formed by oxidation in the absence of any catalyst (226). The oxidation of SO2 catalyzed by nitrogen oxides was important in the eady processes for manufacture of sulfuric acid (qv). Sulfur dioxide reacts with chlorine or bromine forming sulfuryl chloride or bromide [507-16 ]. 

The absorption of sulfur dioxide in alkaline (even weakly alkaline) aqueous solutions affords sulfites, bisulfites, and metabisulfites. The chemistry of the interaction of sulfur dioxide with alkaline substances, either in solution, slurry, or soHd form, is also of great technological importance in connection with air pollution control and sulfur recovery (25,227,235—241). Even weak bases such as 2inc oxide absorb sulfur dioxide. A slurry of 2inc oxide in a smelter can be used to remove sulfur dioxide and the resultant product can be recycled to the roaster (242). 

The anaerobic reaction of sulfur dioxide with aqueous ammonia produces a solution of ammonium sulfite [10192-30-0]. This reaction proceeds efficientiy, even with a gas stream containing as Httie as 1 wt % sulfur dioxide. The sulfur dioxide can be regenerated at a high concentration by acidulation or by stream stripping of the ammonium sulfite solution, or the sulfite can be made to precipitate and the ammonia recovered by addition of lime (243). The process can also be modified to produce ammonium sulfate for use as fertili2er (244) (see Fertilizers). In a variant of this process, the use of electron-beam radiation cataly2es the oxidation of sulfur dioxide in the presence of ammonia to form ammonium sulfate (245). 

Chemical Properties. Anhydrous sodium sulfite is stable in dry air at ambient temperatures or at 100°C, but in moist air it undergoes rapid oxidation to sodium sulfate [7757-82-6]. On heating to 600°C, sodium sulfite disproportionates to sodium sulfate and sodium sulfide [1313-82-2]. Above 900°C, the decomposition products are sodium oxide and sulfur dioxide. At 600°C, it forms sodium sulfide upon reduction with carbon (332). 

Manufacture. Aqueous sodium hydroxide, sodium bicarbonate, sodium carbonate, or sodium sulfite solution are treated with sulfur dioxide to produce sodium metabisulfite solution. In one operation, the mother Hquor from the previous batch is reinforced with additional sodium carbonate, which need not be totally in solution, and then is treated with sulfur dioxide (341,342). In some plants, the reaction is conducted in a series of two or more stainless steel vessels or columns in which the sulfur dioxide is passed countercurrent to the alkaH. The solution is cooled and the sodium metabisulfite is removed by centrifuging or filtration. Rapid drying, eg, in a stream-heated shelf dryer or a flash dryer, avoids excessive decomposition or oxidation to which moist sodium metabisulfite is susceptible. 

Heating the adduct of ethylene oxide and sulfur dioxide with primary alcohols in the presence of alkaH hydhdes or a transition-metal haHde yields dialkyl sulfites (107). Another method for the preparation of methyl alkyl sulfites consists of the reaction of diazomethane with alcohoHc solutions of sulfur dioxide (108). 

Zinc does not react with nitrogen, even at elevated temperatures but zinc nitride, Zn N2, forms with ammonia at red heat. Zinc sulfide, the most common form of zinc in nature, is not reduced direcdy in commercial practice because of reactions of the zinc vapor during condensation. Rather, the sulfide is burned (roasted) to the oxide plus sulfur dioxide before reduction. However, zinc can be reduced to the metal at ca 1300°C with carbon or iron. 

Allied-Signal Process. Cyclohexanone [108-94-1] is produced in 98% yield at 95% conversion by liquid-phase catal57tic hydrogenation of phenol. Hydroxylamine sulfate is produced in aqueous solution by the conventional Raschig process, wherein NO from the catalytic air oxidation of ammonia is absorbed in ammonium carbonate solution as ammonium nitrite (eq. 1). The latter is reduced with sulfur dioxide to hydroxylamine disulfonate (eq. 2), which is hydrolyzed to acidic hydroxylamine sulfate solution (eq. 3). 

Determining the sulfur content in crudes is important because the amount of sulfur indicates the type of treatment required for the distillates. To determine sulfur content, a weighed crude sample (or fraction) is burned in an air stream. All sulfur compounds are oxidized to sulfur dioxide, which is further oxidized to sulfur trioxide and finally titrated with a standard alkali. 

Both barium and sulfur also combine with oxygen to form barium oxide and sulfur dioxide. When 95.0gofBareact with 50.0 g of sulfur, only 65.15 g of BaS are obtained. Assuming 100% yield for the oxides, how many grams of BaO and S02 are formed ... 

Few 1 -benzothiophene-S-oxides 218 were obtained in moderate yields by treatment of 1-arylacetylenes 219 with sulfur dioxide and benzene in the presence of antimony pentafluoride250 (equation 127). A series of cyclic sulphoxides have been prepared by hydrolysis of the corresponding alkoxy sulphonium salts 220251-254 (equation 128). Syn-sulphoxide 221 was obtained in a low yield (15-20%) in the reaction of the dianion of cyclooctatetraene 222 with thionyl chloride255 (equation 129). 

Self-Test K.3A In the Claus process for the recovery of sulfur from natural gas and petroleum, hydrogen sulfide reacts with sulfur dioxide to form elemental sulfur and water 2 H2S(g) + S02(g) — 3 S(s) + 2 H20(1). Identify the oxidizing agent and the reducing agent. 

Iron pyrite, FeS2, is the form in which much of the sulfur exists in coal. In the combustion of coal, oxygen reacts with iron pyrite to produce iron(III) oxide and sulfur dioxide, which... 

When lcad(II) sulfide is treated with hydrogen peroxide, the possible products are either lead(II) sulfate or lead(IV) oxide and sulfur dioxide, (a) Write balanced equations for the two reactions, (b) Using data available in Appendix 2A, determine which possibility is more likely. 

Carmines are dehned as the lakes of carminic acid with various metals. The most used is carmine, the aluminium lake of carminic acid. Carmine is not soluble in water or oils and is also very stable under condition of light, heat, oxidation, and sulfur dioxide." ... 

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