Reduction reactions iodide

Bromide ndIodide. The spectrophotometric determination of trace bromide concentration is based on the bromide catalysis of iodine oxidation to iodate by permanganate in acidic solution. Iodide can also be measured spectrophotometricaHy by selective oxidation to iodine by potassium peroxymonosulfate (KHSO ). The iodine reacts with colorless leucocrystal violet to produce the highly colored leucocrystal violet dye. Greater than 200 mg/L of chloride interferes with the color development. Trace concentrations of iodide are determined by its abiUty to cataly2e ceric ion reduction by arsenous acid. The reduction reaction is stopped at a specific time by the addition of ferrous ammonium sulfate. The ferrous ion is oxidi2ed to ferric ion, which then reacts with thiocyanate to produce a deep red complex. 

Oxaziridines are powerful oxidizing agents. Free halogen is formed from hydrobromic acid (B-67MI50800). Reduction by iodide in acidic media generally yields a carbonyl compound, an amine and two equivalents of iodine from an oxaziridine (1). With 2-alkyl-, 2-acyl and with N-unsubstituted oxaziridines the reaction proceeds practically quantitatively and has been used in characterization. Owing to fast competing reactions, iodide reduction of 2-aryloxaziridines does not proceed quantitatively but may serve as a hint to their presence. 

H2 Is equal to 1 if hydrogen is at atmospheric pressure. If no interchange occurs, Qg 1. The reduction reaction will proceed effectively if log Kp g is not more than 1 or 2 units greater than log Kp Thermal dissociation is not feasible, except for iodides. 

CVD developed slowly in the next fifty years and was limited mostly to extraction and pyrometallurgy for the production of high-purity refractory metals such as tantalum, titanium, and zirconium. Several classical CVD reactionswere developedatthattimeincludingthecarbonyl cycle (the Mond process), the iodide decomposition (the de Boer-Van Arkelprocess)andthemagnesium-reduction reaction (the Kroll process). 

Praseodymium tri-iodide, Prl3, as the starting material for reduction reactions, might be easily produced by the oxidation of praseodymium metal with elemental iodine [17]. With catalytic amounts of hydrogen dissolved in praseodymium metal powder, the reaction temperature can be as low as 230 °C [18]. Sublimation in high vacuum in tantalum tubes yields pure Prl3. 

In acid medium, cadmium iodide solution should exhibit the reduction reactions of I anion. Iodide anion is a fairly strong reducing agent which can reduce many metal ions in their higher oxidation states ... 

The cross-coupling of alkynylzinc halides or fluorinated alkenylzinc halides with fluori-nated alkenyl iodides allows the preparation of a range of fluorinated dienes or enynes - Functionalized allylic boronic esters can be prepared by the cross-coupling of (dialkylbo-ryl)methylzinc iodide 428 with functionalized alkenyl iodides. The intramolecular reaction provides cyclized products, such as 429 (Scheme 109) ° °. In some cases, reduction reactions or halogen-zinc exchange reactions are observed. 

Sulfonium salts of thiepanes are readily formed by electrophilic attack of alkyl halides on the cyclic thioether. Thus, thiepane (35) was found to yield a sulfonium iodide (123), which at elevated temperatures and in the presence of excess methyl iodide underwent ring cleavage to yield 1,6-diiodohexane (isolated as the 1,6-diphenoxy derivative Scheme 24) (53M1206). The alkoxysulfonium salt (124) formed by reaction of (35) with t-butyl hypochlorite (equation 23) was characterized as a stable hexachloroantimonate (67JOC2014). Reduction of thiepane 1-oxide (115) to thiepane has been achieved using an aqueous solution of NaHSC>3 (72JOC919). A hydroxysulfonium salt intermediate (125) has been proposed in the latter reduction reaction which provides a general method for sulfoxide reductions under mild conditions (equation 24). 

Even though alkyl iodides and many alkyl bromides do not require an added reagent for reduction reactions conducted at high concentration, it is advisable to provide an initiator to insure that chains continue at low concentration. 

N-Methylation of secondary amines is usually accomplished either with CH20/HC02H (Leuckart/Clarke-Eschweiler reaction) or with CH20 followed by NaBH4 reduction. Methyl iodide treatment of secondary or tertiary bisben-zylisoquinoline alkaloids leads ultimately to the bis quaternary salts, and, in the presence of base, phenolic alkaloids are also O-alkylated. For example, lin-doldhamine (165) on treatment with ethyl bromide in 0.5 N ethanolic KOH gave the N,N,0,0,0-pentaethy 1 derivative (108, Section II,C,56) daurisoline was similarly permethylated with Mel and base (68, Section II,C,19). 

Vicinal dibromides (two bromines on adjacent carbon atoms) are converted to alkenes by reduction with iodide ion in acetone. This debromination is rarely an important synthetic reaction, because the most likely origin of a vicinal dibromide is frombromi-nation of an alkene (Section 8-10). We discuss this reaction with dehydrohalogenation because the mechanisms are similar. 

The determination of the active oxygen in ozonides with sodium iodide in glacial acetic acid gives reliable values only in the case of ketozonides. The reaction products are ketones.96 Iodometric peroxide determination in the case of aldozonides gives less than 60% of the theoretical value 112 carboxylic acids are formed as well as aldehydes. The reduction with iodide ions probably suffers competition from the reaction shown in Eq. (7). 

Other functional polyfluorinated compounds are available by addition of perhaloalkyl halides to enol derivatives, e.g. formation of 1 and 2 (see also Table 4). The adducts formed from enol acetates or enol ethers are not very stable and their hydrolysis to give a-perhaloalkyl aldehydes or ketones is often rapid. However, the enol derivatives can be transformed either to give ketals using alcohols or to give various products by oxidation and reduction reactions. The peculiar perfluoroalkyl iodide addition to enamines is spontaneous at room temperature, e.g. formation of 3. ... 

Cupric bromide, CiiBr., is a black solid obtained by reaction of copper and bromine or by solution of cupric oxide, CuO, in hydro bromic acid. It is interesting that cupric iodide, Culo, does not exist when a solution containing cupric ion is added to an iodide solution there occurs an oxidation-reduction reaction, with precipitation of (uprous iodide, Cul ... 

Divalent samarium is known to reduce alkyl halides. However, reductions of iodides and bromides in tetrahydrofuran (THF) require a long reaction time and chlorides are not reduced even at refluxing temperature. 

In view of what has been discussed in the previous section (see Section II.A.2) on the influence of the halide in Grignard reagents, it is of interest to mention that Leroide reported the formation of considerably more of the reduction reaction product when the iodide was used, when compared with the results obtained with the chloride and the bromide. The yield ratios of secondary alcohol versus tertiary alcohol were (sec. alcohol tert. alcohol) 1.2,2.1, and 10, respectively, for the chloride, bromide, and iodide Grignard reagent. 

Staich, which forms a blue complex with triiodide ion, is a widely used specific indicator in oxidation/reduction reactions involving iodine as an oxidant or iodide ion as a reductant. A starch solution containing a little triiodide or iodide ion can... 

Acyloxaziridines are easily obtained from compounds unsubstituted at nitrogen by reaction with acid chlorides or isocyanates. Acylation proceeds so smoothly that, in the amination of carbonyl compounds, oxaziridine compounds are obtained in better yields on addition of acid chlorides than in the absence of the acylating agent. With aliphatic aldehydes, amination does not succeed at all except in the presence of benzoyl chloride. Proof of structure comes from reduction by iodide to give the acid amide and carbonyl compound. 

Catalytic reduction of double bonds using Pd/C (10.5) or removal of benzyl ethers [61] (10.6) has been successfully conducted in BTF. Hydride reductions are possible in BTF as well. However, a cosolvent hke THF or diethyl ether is necessary when using Hthium aluminum hydride, because of the insolubiUty of LAH in BTF. The reduction of thiocarbamates with LAH [62] in BTF proceeded in 95% yield (10.7), provided that the concentration was 4 times less compared to the reaction in THF. Reduction of iodides [53] (10.8) and carboxyhc esters... 

Iodine, I2, has many uses, including the production of dyes, antiseptics, photographic film, pharmaceuticals, and medicinal soaps. It forms when chlorine, CI2, reacts with iodide ions in a sodium iodide solution. Which of the following half-reactions for this oxidation-reduction reaction describes the oxidation, and which one describes the reduction ... 

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