Iodine reaction with acetone

Trichloroacetone [921-03-9] (13a) is prepared by chlorination of acetone. The reaction is nonselective and the required compound is isolated by distillation. The selectivity has been improved by catalyzing the reaction with iodine (31). 

Complexes containing from one to six carbonyl groups are known and all obey the 18-electron rule. The colorless salt [Tc(CO)6]A1C14 is formed by the reaction of [Tc(CO)5C1] with A1C13 under 300 atm CO pressure and is soluble in THF, acetone, and methanol and stable in aqueous solution (65). The carbonyl halides [Tc(CO)5X] (X = Cl, Br, I) may be prepared by the reaction of the halogen with [Tc2(CO)10]. Reaction with chlorine and bromine occurs readily at room temperature but reaction with iodine is extremely slow. The iodide has been prepared by the high-pressure carbonylation of [Tc(CO)4I]2 (45). An alternative... 

As already noted, azines are unreactive towards iodine monofluoride however, it has been shown that azines react with bromine trifluoride under mild reaction conditions, yielding ew-difluorides (Table 1). The reagent bromine trifluoride is readily prepared from its elements, although caution should be taken because bromine trifluoride reacts violently with water and acetone. 2,4-Dinitrophcnylhydrazonescan also be used as the hydrazonederivatives in reactions with bromine trifluoride (Table 2). No significant byproducts, unlike the reactions with iodine monofluoride, are obtained in this case. The reactions with bromine trifluoride are not sensitive to the stereochemistry of the C = N bond, and both E- and Z-isomers react with the same efficiency. 

In current industrial practice gas chromatographic analysis (glc) is used for quahty control. The impurities, mainly a small amount of water (by Kad-Fischer) and some organic trace constituents (by glc), are deterrnined quantitatively, and the balance to 100% is taken as the acetone content. Compliance to specified ranges of individual impurities can also be assured by this analysis. The gas chromatographic method is accurately correlated to any other tests specified for the assay of acetone in the product. Contract specification tests are performed on product to be shipped. Typical wet methods for the deterrnination of acetone are acidimetry (49), titration of the Hberated hydrochloric acid after treating the acetone with hydroxylamine hydrochloride and iodimetry (50), titrating the excess of iodine after treating the acetone with iodine and base (iodoform reaction). 

The oxygen atom at 21 is similarly an expendable group. Reaction of 241 (obtained from 185 by the usual procedure for introduction of the 9a-fluoro group) with methanesulfonyl chloride affords the 21 mesylate (242a). Replacement of the leaving group at 21 with iodine by means of potassium iodide in acetone followed by reduction of the halogen with zinc in acetic acid leads to fluorometholone (243). ... 

Cyanide and thiocyanate anions in aqueous solution can be determined as cyanogen bromide after reaction with bromine [686]. The thiocyanate anion can be quantitatively determined in the presence of cyanide by adding an excess of formaldehyde solution to the sample, which converts the cyanide ion to the unreactive cyanohydrin. The detection limits for the cyanide and thiocyanate anions were less than 0.01 ppm with an electron-capture detector. Iodine in acid solution reacts with acetone to form monoiodoacetone, which can be detected at high sensitivity with an electron-capture detector [687]. The reaction is specific for iodine, iodide being determined after oxidation with iodate. The nitrate anion can be determined in aqueous solution after conversion to nitrobenzene by reaction with benzene in the presence of sulfuric acid [688,689]. The detection limit for the nitrate anion was less than 0.1 ppm. The nitrite anion can be determined after oxidation to nitrate with potassium permanganate. Nitrite can be determined directly by alkylation with an alkaline solution of pentafluorobenzyl bromide [690]. The yield of derivative was about 80t.with a detection limit of 0.46 ng in 0.1 ml of aqueous sample. Pentafluorobenzyl p-toluenesulfonate has been used to derivatize carboxylate and phenolate anions and to simultaneously derivatize bromide, iodide, cyanide, thiocyanate, nitrite, nitrate and sulfide in a two-phase system using tetrapentylammonium cWoride as a phase transfer catalyst [691]. Detection limits wer Hi the ppm range. 

Halogens, See also Bromine (Br) Chlorine (Cl) Fluorine (F) Iodine (I) higher aliphatic alcohols, 2 5 in N-halamines, 13 98 reactions with acetaldehyde, 1 105 reactions with acetone, 1 163 reactions with acetylene, 1 180 reactions with alkanolamines from olefin oxides and ammonia, 2 125—126 reactions with aluminum, 2 284—285, 349-359... 

PiCHO + H2NC6H4N(CH3)2 This is the favored procedure for preparing the aldehyde (Refs 11 24). Reaction (A) is done at room temp in pyridine, using iodine as catalyst (Ref 11), or in alcohol-acetone mixt with anhyd Na carbonate as catalyst (Ref 24) earlier procedures (see refs cited in Vol 2, B35-R) are reported to be unsatisfactory (Ref 11). Reaction (B) proceeds in strong aq hydrochloric acid overall yields are 39—52%. Reaction (A) proceeds in 80% yield in aq medium in the presence of light (Ref 90), with less by-product formation than noted in the other methods... 

The methyl group in compound 172 can be easily replaced by chlorine or iodine by reaction with HC1 or I2. The chlorosubstituted compound has found to be a good precursor for nucleophilic substitution reactions with NaX (X = Br, I, or SCN) in acetone (Scheme 4) <2001JCD2593>. 

Iodine was determined by GC by Hasty [652]. He carried out the conversion into iodoacetone by reaction with an aqueous solution of acetone (0.5 M) and sulphuric acid (0.5 M) for 30 min. The reaction mixture was then extracted with n-hexane and aliquots were analysed on a column packed with 5% of SE-30 on Varaport. By using an ECD, iodine concentrations down to 1 jug/ml in an aqueous sample could be determined. The sensitivity could be increased by using other ketones, e.g., 2-butanone or 2-pentanone [653]. The products from the reaction with these ketones provide higher ECD response and are more extractable with n-hexane. The utilization of these properties makes it possible to extend the determination of iodine down to concentrations of nanograms per millilitre. 

A pure sample of (tj6-benzene)(rjs -cyclopentadienyl)molybdenum (3.0 g, 12.5 mmole), prepared as in Sec. A above, is dissolved in benzene (60 mL). The resulting deep-yellow solution is stirred and treated with iodine (1.7 g, 6.70 mmole) in light petroleum ether (bp 100-120°, 150 mL). Immediate reaction produces a dark precipitate and a purple solution. The solution is concentrated to about 100 mL, and the precipitate is collected and recrystallized from acetone/ethanol. Yield 50% (2.3 g). Anal. Calcd. for CnHuIMo C, 36.1 H, 3.0. Found C, 35.8 H, 3.0. 

Chitosan is insoluble in water, concentrated acids, alkalis, alcohol, and acetone, but dissolves readily in dilute acids. Water-soluble salts of chitosan include the nitrate and the perchlorate. As described on p. 377, formation of chitosan sulfate and the color reaction of chitosan with iodine have been widely used as qualitative tests for the detection of chitin. Nitration of chitosan with a mixture of acetic and nitric acids or with absolute nitric acid enabled both the free ester and its nitrate salt to be isolated. The perchlorate salt of this ester was also prepared, but it was unstable. Chitosan can be W-acetylated to give products similar to chitin except for their greatly reduced chain-length W-formyl-, iV-propionyl-, JV-butyryl-, and iV-benzoyl-chitosan were also prepared. ... 

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