Iodine Monochloride Procedures

Styrene butadiene copolymers contain residual double bonds which enable the butadiene content of the copolymer to be determined  

In this procedure, the polymer is reacted with an excess of standard iodine monochloride dissolved in glacial acetic acid ( Wijs reagent )  

After reaction completion, excess iodine monochloride is reacted with potassium iodide and the liberated iodine estimated by titration with standard sodium thiosulfate  

The double bond content of the original polymer can be calculated from the measured consumption of iodine monochloride. 

The solid gel, separated from high-impact polystyrene by solvent extraction procedures, is completely insoluble in chloroform and in the iodine monochloride reagent solution. A contact time with chloroform of 90 hours and a reaction time of 75 minutes with the reagent is required. 

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Altenau and co-workers [41] applied time averaging NMR to the determination of low percentages of termonomer such as 1,4 hexadiene, dicyclopentadiene, and ethylidene norbornene in ethylene-propylene termonomers. They compared results obtained by NMR and the iodine monochloride procedure of Lee and co-workers [42]. The chemical shifts and splitting pattern of the olefinic response were used to identify the termonomer. Table 3.6 compares the amount of termonomer found by the NMR method of Altenau and co-workers [41] and by iodine monochloride procedures. The termonomers were identified by NMR and IR spectroscopy. 

Table 3.12 compares the amount of termonomers found by the NMR method of Altenau and co-workers [81] and by iodine monochloride procedures [113]. The termonomers were identified by NMR and IR spectroscopy. 

Both the gel and toluene soluble fractions are reserved for determination of unsaturation by the iodine monochloride method. To determine unsaturation in styrene-butadiene rubbers with good accuracy using the iodine monochloride procedure, it was found necessary to contact the sample with chloroform for 15 hours before reaction with iodine monochloride. Even with a 30 hour reaction period, a constant iodine-value is obtained only when a five-fold excess of iodine monochloride reagent is used. 

Kranz and co-workers [126] have shown that acrylonitrile can he determined in styrene - butadiene - acrylonitrile terpolymers via a determination of organic nitrogen by the Kjeldahl procedure. Styrene units can be can be determined by infrared spectroscopy. Butadiene units can be determined by the iodine monochloride procedure. The compositional analysis and details of the microstructure of butadiene - acrylonitrile copolymers can be obtained by Raman spectroscopy [127]. 

The iodination reaction can also be conducted with iodine monochloride in the presence of sodium acetate (240) or iodine in the presence of water or methanolic sodium acetate (241). Under these mild conditions functionalized alkenes can be transformed into the corresponding iodides. AppHcation of B-alkyl-9-BBN derivatives in the chlorination and dark bromination reactions allows better utilization of alkyl groups (235,242). An indirect stereoselective procedure for the conversion of alkynes into (H)-1-ha1o-1-alkenes is based on the mercuration reaction of boronic acids followed by in situ bromination or iodination of the intermediate mercuric salts (243). 

Filimonov et al. reported a synthesis of 3,6-diiodocarbazole (387) by iodination of carbazole (1). For the iodination, the required electrophilic iodine was generated by reacting iodine monochloride (ICl) with silver trifluoroacetate (CFsCOOAg) in acetonitrile. Following this procedure, 3,6-diiodocarbazole (387) was obtained in almost quantitative yield (871) (Scheme 5.270). 

The iodination of pyrimidines requires the presence of an activating substituent, and is normally performed with reagents such as A -iodosuccinimide (NI8) or iodine monochloride (ICl). A microwave-assisted procedure for the rapid and high-yielding C-5 iodination of substituted pyrimidinones and pyrimidine nucleosides with NIS in dimethylfor-mamide (DMF) has been developed, and thus the iodination of uracil occurred in 98% yield with just 3 min reaction time <200381039>. 

The residual double bonds of poly(methyl acrylate) have been determined by bromination [9,27]. Bromination is accomplished through the addition of potassium bromide to potassium bromate in acidic medium [9]. Styrene-butadiene copolymers contain residual double bonds. The butadiene content of the copolymer has been determined by an iodine monochloride titration procedure [9],... 

Iodoaniline has been prepared by the reduction of -nitro-iodobenzene 1 by the hydrolysis of -iodoacetanilide formed by the action of iodine monochloride on acetanilide 2 and by the direct iodination of aniline.3 The method described here is an adaptation of the procedure used by Wheeler/ and by Hann and Berliner 5 for the iodination of the toluidines. 

For procedures for non-enzymatic iodination of proteins, most frequently carried out with iodine monochloride, reference should be made to the lucid treatment by Roholt and Pressman (1972). 

The iodinating agent in our procedure is iodine monochloride, ICl. Because iodine is the less electronegative of the two halogens, this reagent is polarized to make the iodine atom electrophilic, and it may dissociate to give Cl and H. The electrophile for the reaction is thus either polarized molecular I-Cl or iodonium ion... 

Kabalka, G. W., Gooch, E. E. 1980. A mild and convenient procedure for the conversion of aUcenes into alkyl iodides via the reaction of iodine monochloride with organoboranes. J. Org. Chem. 45 3578-3580. 

If gold was present in the fission product solution, the iodine was converted to the monochloride as described above and the solution was boiled to expel excess chlorine. Then sufficient sulfurous acid was added to reduce gold (III) to the free element and iodine monochloride to iodide. After removal of the gold and excess sulfur dioxide, sodium chlorate was added and the solution made 6 M in hydrochloric acid. Then the procedure was taken up at the point where the iodine monochloride was extracted into butyl acetate. 

Typical procedure Iodine monochloride (l.OM in DCM, 1.3 equiv) is added dropwise to a solution of the methoxymethyl (MOM) or benzyloxymethyl (BOM) protected homoaUyhc alcohol (1 equiv) in toluene (0.01 M) at —78 C. After 10 minutes, a mixture of diisopropylamine water (10 1) is added and the dry ice bath is removed. The red solution turns colorless and is stirred for another 40 minutes before dilution with water. The mixture is extracted and purified by silica colunm chromatography on silica gel to afford the monoprotected jy -l,3-diol as an oil. 

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