Addition chloramines

In reahty the chemistry of breakpoint chlorination is much more complex and has been modeled by computer (21). Conversion of NH/ to monochloramine is rapid and causes an essentially linear increase in CAC with chlorine dosage. Further addition of chlorine results in formation of unstable dichloramine which decomposes to N2 thereby causing a reduction in CAC (22). At breakpoint, the process is essentially complete, and further addition of chlorine causes an equivalent linear increase in free available chlorine. Small concentrations of combined chlorine remaining beyond breakpoint are due primarily to organic chloramines. Breakpoint occurs slightly above the theoretical C1 N ratio (1.75 vs 1.5) because of competitive oxidation of NH/ to nitrate ion. Organic matter consumes chlorine and its oxidation also increases the breakpoint chlorine demand. Cyanuric acid does not interfere with breakpoint chlorination (23). 

Protonated /V-chloroalkyl amines under the influence of heat or uv light rearrange to piperidines or pyrroHdines (Hofmann-Lriffler reaction) (88). The free-radical addition of alkyl and dialkyl-/V-chloramines to olefins and acetylenes yields P-chloroalkji-, P-chloroalkenyl-, and 8-chloroalkenylamines (89). Various N-hiomo- and N-chloropolyfluoroaLkylarnines have been synthesized whose addition products to olefinic double bonds can be photolyzed to fluoroazaalkenes (90). 

Chloral forms well-crystallized adducts (126) with diaziridines containing at least one NH group (B-67MI50800). Carbonyl addition products to formaldehyde or cyclohexanone were also described. Mixtures of aldehydes and ammonia react with unsubstituted diaziridines with formation of a triazolidine ring (128). Fused diaziridines like (128) are always obtained in ring synthesis of diaziridines (127) from aldehyde, ammonia and chloramine. The existence of three stereoisomers of compounds (128) was demonstrated (76JOC3221). Diaziridines form Mannich bases with morpholine and formaldehyde (64JMC626), e.g. (129). 

Compound (253) is formed from benzaldehyde and methylhydroxylamine-O-sulfonic acid in 35% yield. With ethyl-substituted chloramine or hydroxylamine-O-sulfonic acid yields do not exceed 10%, which is assumed to be due to steric hindrance and is foreseeable for both carbonyl addition and O —N bond formation. 

Chlorine is desirable as a bulk pretreatment biocide for inlet water, but its subsequent removal upstream of the membrane is absolutely necessary ana difficult. NaHSO,3 is a common additive to dechlorinate before membranes. It is customarily added at 3-5 mg/1, an excess over the stoichiometric requirement. NH3 is sometimes added to convert the chlorine to chloramine, a much less damaging biocide. Heavy metals present in seawater seem to amplify the damaging effects of chlorine and other oxidants. 

Chloramines (as as of as of Eye/nose irritation Water additive used... 

Chemical precipitation Precipitation induced by addition of chemicals the process of softening water by the addition of lime and soda ash as the precipitants. Chloramines Compounds formed by the reaction of hypochlorous acid (or aqueous chlorine) with ammonia. 

Hydroxy- 6-diazoandrost-5-en- l-one (96) To a stirred solution of 750 ml of methanol and 144 ml of 5 A sodium hydroxide is added 36 g (0.114 mole) of oximino ketone. Concentrated aqueous ammonia (56.6 ml, 0.850 mole) is then added followed by dropwise addition of 265 ml of cold 3 M sodium hypochlorite at a rate sufficient to maintain the temperature of the exothermic reaction mixture at 20 + 1° while cooling with an external ice bath. At temperatures below 20° appreciable amounts of a-mono- and a-dichloro ketones are obtained above 20° the chloramine decomposes before reacting with the oximino ketone. As soon as all of the sodium hypochlorite has been added, the ice bath is removed and the reaction mixture is allowed to warm to room temperature with continued stirring for 6 hr. The reaction mixture is diluted with an equal volume of water and extracted twice with... 

In addition there is a further rapid but undesirable reaction with chloramine which destroys the N2H.1 produced ... 

The rate of the diaziridine formation shows that the chloramine is attacked by the Schiff s base. Although ethereal chloramine solutions are only decomposed after weeks of standing, in the presence of a Schiffs base the chloramine is consumed after a few hours. The Schiff s base therefore does not enter into the reaction merely after the decomposition of the chloramine as it would have to do if formula 39 was an intermediate. Probably the chloramine adds onto the Schiff s base [Eq. (37) ] and ring closure of the geminal addition ]>roduct occurs. ... 

Organoboranes react with a mixture of aqueous NH3 and NaOCl to produce primary amines. It is likely that the actual reagent is chloramine NH2CI. Chloramine itself,hydroxylamine-O-sulfonic acid in diglyme, and trimethyl-silyl azide " also give the reaction. Since the boranes can be prepared by the hydroboration of alkenes (15-16), this is an indirect method for the addition of NH3 to a double bond with anti-Markovnikov orientation. Secondary amines can be prepared by the treatment of alkyl- or aryldichloroboranes or dialkylchlorobor-anes with alkyl or aryl azides. 

Hexa(hydroxyethyl)pararosaniline nitrile has been used in a chemical radiochromic dosimeter.130 Ferricyanide oxidation of leuco Crystal Violet to Crystal Violet dye finds use in detection of various heavy metals131 at trace quantities. Oxidation of leuco triphenylmethanes by chloramine-T is catalyzed by iodide and therefore is used for detection of iodide.132 On the other hand, the inhibition of the catalytic effect of iodide by some ions can be used for determining traces of Ag(I), Hg(II), Pd(II). In addition, the triphenylmethane leuco dyes, phenolphthalein or phenol red are used extensively as indicators in calorimetric and titrimetric determinations. 

The success of this reaction was ascribed to the solubility of the chlorozinc intermediate, whereas other chloramine-T derivatives (e.g. the sodium salt) are insoluble. An alternative non-nitrene pathway was not eliminated from consideration. On the other hand, no aromatic substitution or addition, characteristic of a free sulphonyl nitrene (see below), took place on treatment of jV,lV-dichloromethanesulphonamides with zinc powder in benzene in the cold or on heating. The only product isolated was that of hydrogen-abstraction, methanesulphonamide 42>, which appears to be more characteristic of the behaviour of a sulphonyl nitrene-metal complex 36,37). Photolysis of iV.iV-dichloromethanesulphonamide, or dichloramine-B, or dichloramine-T in benzene solution led to the formation of some unsubstituted sulphonamide and some chlorobenzene but no product of addition of a nitrene to benzene 19>. 

Amines can give rise to chloramines during hypochlorite bleaching (Scheme 10.83). In addition to increasing AOX values, this can result in cellulose oxidative degradation by hypochlorite on subsequent hydrolysis of the chloramines (Scheme 10.84) [448]. 

Radiolabel 55 nmol of SASD using IODO-GEN (Thermo Fisher) and 40 pCi Na 125I for 30 seconds. Do not use chloramine-T, since termination of the iodination reaction with this reagent involves addition of a reducing agent which may cleave the disulfide bonds of the crosslinker. 

HOCl-mediated protein oxidation accelerates under pathophysiological conditions. Thus, proteins from extracellular matrix obtained from advanced human atherosclerotic lesions contained the enhanced levels of oxidized amino acids (DOPA and dityrosine) compared to healthy arterial tissue [44], It was also found that superoxide enhanced the prooxidant effect of hypochlorite in protein oxidation supposedly by the decomposition of chloramines and chlor-amides forming nitrogen-centered free radicals and increasing protein fragmentation [45], In addition to chlorination, hypochlorite is able to oxidize proteins. The most readily oxidized amino acid residue of protein is methionine. Methionine is reversibly oxidized by many oxidants including hypochlorite to methionine sulfide and irreversibly to methionine sulfone [46] ... 

The concentration of copper(II) has a pronounced effect on the course of the reaction. In the presence of very low copper(II) concentrations, oxidation of allyl radical 69 is slow and major amounts of allyl radical dimer are formed. In the presence of very high concentrations of copper(II), radical 68 is oxidized rapidly before addition to diene can take place. An optimum yield of product 71 can therefore only be achieved at certain copper(II) concentrations. The metal-ion-promoted addition of chloramines to butadiene appears to follow the same mechanism93. 

Interesting examples of the addition of N-nucleophiles to nitrile oxides are syntheses of chelated Z-amidoxime, N-[2-(dimethylaminomethyl)phenyl]mesitylene-carboamidoxime (118), and pyranosyl amidoximes (119) from the respective nitrile oxides and amines. Aromatic aldoximes undergo unusual reactions with chloramine-T (4 equiv, in refluxing MeOH). N-(p-toly 1 )-N-(p-tosy 1 )benzamides are formed via addition of 2 equiv of chloramine-T to the intermediate nitrile oxide followed by elimination of sulfur dioxide (120). 

Vigreux column must extend sufficiently into the top of a well-ventilated hood to entrain effectively the fumes that will be generated later in the operation. The phenol is melted with the aid of an external oil bath or Glascol heating mantle and heated to about 100°. The heating bath is removed, and 27.6 g. (1.20 g. atoms) of sodium in cubes about 1 cm. on a side or smaller is added to the stirred mixture at such a rate that the temperature does not exceed 150-160°. The molten mass gradually becomes dark red in color as the sodium dissolves. While the addition and solution of the sodium is proceeding, a cold solution of about 0.25 mole of chloramine in 250 ml. of ether is prepared (Note 2). 

When the addition is completed, the heat source is removed and the dark-colored contents are allowed to cool until another 0.25 mole of ethereal chloramine has been prepared and is ready for use a wait of 1.5-2 hours between chloramine additions is convenient but not essential to the success of the experiment. The cooled reaction mixture is then reheated to 150°, and the process is repeated. This sequence is repeated until a total of four 0.25-mole portions of chloramine are added. 

Additional products of the myeloperoxidase system depend upon the local environment. For example, HOC1 can react with nitrogen-containing compounds such as biological amines to form chloramines ... 

V-(p-Toluenesulphonyl)sulphilimines have been prepared under solidtliquid phase-transfer catalytic conditions from the reaction of sulphides with Chloramine-T [25] (see Section 4.5). Osmium-catalysed oxyamination of alkenes by Chloramine-T under two-phase conditions is aided by the addition of benzyltriethylammonium chloride. p-Aminoalkanols are obtained in good yields (60-75%) [26]. 

Isocyanides and arylamines react with Chloramine-T when catalysed by the addition of benzyltriethylammonium chloride to produce (V-tosylguanidines in good yield (58-78%) [27], The reaction is thought to proceed via the initial A-chlorination of the arylamine. 

In addition to sulfimides, the nitrogen analogs of sulfinates and sulfinamides are chiral and have been obtained as optically active compounds. For instance, the synthesis of diastereomeric menthyl p-toluenesulfinimidoates 90 mentioned above was effected by Cram and his collaborators (18,137) on two ways. The first comprised the reaction of racemic A -tosyl-p-tolueneiminosulfinyl chloride 92 with menthol, followed by separation of the diastereomers of 90, whereas in the second method the reaction of the ester (->45 with chloramine T was utilized. 

Iodine was found to be an efficient catalyst for the aziridination of alkenes (Scheme 6) utilizing chloramine-T (A-chloro-A-sodio-p-toluenesulfonamide) as the nitrogen source. For example, when 2 equiv. of styrene (45a) were added to chloramine-T in the presence of a catalytic amount of iodine (10mol%) in a 1 1 solvent mixture of acetonitrile and neutral buffer, the corresponding aziridine (46) was obtained in 91% yield. The reaction proved to work with other acyclic and cyclic alkenes, such as oct-l-ene and cyclohexene. The aziridination of para-substituted styrene derivatives (45b-e) demonstrated that, as expected for an electrophilic addition, electron-rich alkenes reacted faster than electron-poor alkenes. However, with 1 equiv. of I2, mainly iodohydrin (47) was formed. A catalytic cycle has been proposed to account for the fact that only a catalytic amount of iodine is required (Scheme 1) ... 

Urine Addition of sodium chloride, pH adjustment to 6, extraction with chloroform, extraction of chloroform extract with 3 N HCL addition of chloramine-T and extraction of colored product into chloroform. Absorbance at 457 nm 1-2 ppb ( g/L) 68 (4.6% RSD) Roberts and Rossano 1982... 

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