Of hydroxylamine

Luckhaus D 1997 The rovibrational spectrum of hydroxylamine a combined high resolution experimental and theoretical study J. Chem. Phys. 106 8409-26... 

Luckhaus D 1997 The rovibrational dynamics of hydroxylamine Ber. Bunsenges. Phys. Chem. 101 346-55... 

Metallic Derivatives, (a) Cuprous Acetylide. CujCg. Prepare an ammoniacal solution of cuprous chloride by first adding dilute ammonia to 2-3 ml. of dilute copper sulphate solution until the initial precipitate just redissolves and a clear deep-blue solution is obtained now add an aqueous solution of hydroxylamine hydrochloride drop by drop with shaking until the solution becomes first green and then completely colourless, the cupric salt being thus reduced to the cuprous derivative. 

Prepare a solution of 12 5 g. of hydroxylamine hydrochloride in 20 ml. of water contained in a too ml. conical flask. Dissolve 7 g. of powdered sodium hydroxide in 20 ml. of water, cool the solution in ice-water, and then add it to that of the hydroxylamine hydrochloride. Place a thermometer in the mixed solution, and chill the flask in ice-water until the temperature of the solution is between 5 and 10 . Now add 12 ml. (9 5 gO of dry acetone (preferably from a burette to ensure... 

B) Preparation of the Cuprous Solution, Add 85 ml. of concentrated ammonia solution (d, o-o88) to a solution of 50 g. of crystalline copper sulphate in 200 ml. of water, and cool to 10 . Dissolve 14 5 g. of hydroxylamine hydrochloride (or 17-4 g. of the sulphate) in 50 ml. of water, cool to 10 , and add a solution of 9 g. of sodium hydroxide in 30 ml. of water. Without delay add this hydroxylamine solution with stirring to the copper solution, which will be immediately reduced, but will retain a blue colour. 

Place 80 g, of hydroxylamine sulphate (or 68-5 g. of the hydrochloride), 25 g. of hydrated sodium acetate, and 100 ml. of water in a 500 ml. flask fitted with a stirrer and a reflux water-condenser, and heat the stirred solution to 55-60°. Run in 35 g (42 nil,) of -hexyl methyl ketone, and continue the heating and vigorous stirring for ij hours. (The mixture can conveniently be set aside overnight after this stage.) Extract the oily oxime from the cold mixture twice with ether. Wash the united ethereal extract once with a small quantity of water, and dry it with sodium sulphate. Then distil off the ether from the filtered extract, preferably using a distillation flask of type shown in Fig. 41 (p. 65) and of ca, 50 ml, capacity, the extract being run in as fast as the ether distils, and then fractionally distil the oxime at water-pump pressure. Collect the liquid ketoxime, b.p. 110-111713 mm. Yield, 30-32 g. 

Cyclohexanone oxime. Add 20 g. (21 ml.) of cyclohexanone to a solution of 17 g. of hydroxylamine hydrochloride in 40 ml. of water, and cool the mixture in ice-water. Add a solution of 13 g. of anhydrous sodium carbonate in 40 ml. of water slowly to the mixture, stirring the latter with a 100° thermometer, and maintaining the temperature of the mixture at 20-25° meanwhile. The oxime rapidly separates. Stir the complete mixture at intervals, and after 10 minutes filter the oxime at the pump, drain thoroughly and dry it in a (vacuum) desiccator. Yield of crude oxime, 20 g. Recrystallise from petroleum (b.p. 100-120 ) and dry over paraffin wax (p. 19). Yield of pure oxime, 16 g., m.p. 88°. 

To a few drops of the ester, add 0 2 g. of hydroxylamine hydrochloride and about 5 ml. of 10% NaOH solution and gently boil the mixture for 1-2 minutes. Cool and acidify with HCl, cool again and then add a few drops of FeClj solution. A violet or deep red-brown colour develops immediately. 

Hydroxamic acid formation. To 0 1 g. of acetic anhydride, add 0 1 g. of hydroxylamine hydrochloride and 5 ml. of 10% NaOH solution. Boil the mixture for i minute, cool and acidify with dilute... 

B) Oximes. Dissolve i g. of the quinone in 5 ml. of glacial acetic acid. Dissolve i g. of hydroxylamine hydrochloride in 10 ml. of 10% aqueous sodium acetate solution and shake the mixture for 5 minutes. Cool, filter off the dioxime and recrystallise from ethanol. (M.ps., p. 549.)... 

Dissolve 5 g. of hydroxylamine hydrochloride in 10 ml. of water in a small conical flask and add a solution of 3 g. of sodium hydroxide in 10 ml. of water. Cool the solution in cold or ice water, and add 6 g. (7-6 ml.) of acetone slowly. Cool the flask, shake well, and leave overnight, during which time the oxime may crystallise out. If no crystals appear, cork the flask and shake vigorously when the acetoxime usually separates as colourless crystals. Filter the crystals at the pump, dry rapidly between filter paper (yield 2- 6 g.) and determine the m.p. (59°). Extract the filtrate with two 20 ml. portions of ether, and remove the solvent a further 0 - 5 g. of acetoxime (m.p. 60°) is obtained. Recrystallise from light petroleum, b.p. 40-60° CAUTION inflammable) to obtain the pure acetoxime, m.p. 60°. Acetoxime sublimes when left exposed to the air. 

Dissolve 2 5 g. of hydroxylamine hydrochloride and 4 g. of crystallised sodium acetate in 10 ml. of water in a small flask or in a test-tube. Warm the solution to about 40° and add 2 5 g. of cyclohexanone. Stopper the vessel securely with a cork and shake vigorously for a few minutes the oxime soon separates as a crystalline solid. Cool in ice, filter the crystals at the pump, and wash with a little cold water. RecrystaUise from light petroleum, b.p. 60-80°, and dry the crystals upon filter paper in the air. The yield of pure cycZohexanone oxime, m.p. 90°, is 2 -5 g. 

Oximes. The method given for semicarbazones (see 2) may be employed use 1 g. of hydroxylamine hydrochloride, 2 g. of crystallised sodium acetate and 0 5 g. of the aldehyde or ketone. It is usually advisable to warm on a water bath for 10 minutes. 

For water insoluble aldehydes or ketones, the following alternative procedure may be used. Reflux a mixture of 0-6 g. of the aldehyde or ketone, 0 5 g. of hydroxylamine hydrochloride, 5 ml. of ethanol and 0 5 ml. of pyridine on a water bath for 15-60 minutes. Remove the alcohol either by distillation (water bath) or by evaporation of the hot solution in a stream of air (water pump). Add 5 ml. of water to the cooled residue, cool in an ice bath and stir until the oxime crystallises Filter off the solid, wash it with a little water and dry. Recrystallise from alcohol (95 per cent, or more dilute), benzene, or benzene - light petroleum (b.p. 60-80°). 

In a 250 ml. conical flask mix a solution of 14 g. of sodium hydroxide in 40 ml. of water and 21 g. (20 ml.) of pure benzaldehyde (Section IV,115). Add 15 g. of hydroxylamine hydrochloride in small portions, and shake the mixture continually (mechanical stirring may be employed with advantage). Some heat is developed and the benzaldehyde eventually disappears. Upon coohiig, a crystalline mass of the sodium derivative separates out. Add sufficient water to form a clear solution, and pass carbon dioxide into the solution until saturated. A colourless emulsion of the a or syn-aldoxime separates. Extract the oxime with ether, dry the extract over anhydrous magnesium or sodium sulphate, and remove the ether on a water bath. Distil the residue under diminished pressure (Fig. 11,20, 1). Collect the pure syn-benzaldoxime (a-benzald-oxime) at 122-124°/12 mm. this gradually solidifies on cooling in ice and melts at 35°. The yield is 12 g. 

Oximes (compare Section III,74,B). The following procedure has wide application. Dissolve 0-5 g. of hydroxylamine hydrochloride in 2 ml. of water, add 2 ml. of 10 per cent, sodium hydroxide solution and 0-2 g. of the aldehyde (or ketone). If the latter is insoluble, add just sufficient alcohol to the mixture to give a clear solution. Heat the mixture under reflux for 10-15 minutes, and then cool in ice. If crystals separate, filter these off, and recrystallise from alcohol, dilute alcohol, benzene or light petroleum (b.p. 60-80°). If no solid separates on cooling, dilute with 2-3 volumes of water, filter the precipitated sohd, and recrystallise. 

Veratronitrile, Dissolve 83 g. of veratraldehyde in 200 ml. of warm rectified spirit in a 1 litre bolt-head flask, and add a warm solution of 42 g. of hydroxylamine hydrochloride in 50 ml. of water. Mix thoroughly and run in a solution of 30 g. of sodium hydroxide in 40 ml. of water. Allow the mixture to stand for 2-5 hours, add 250 g. of crushed ice, and saturate the solution with carbon dioxide. The aldoxime separates as an oil allow the mixture to stand for 12-24 hours in an ice chest or refrigerator when the oil will sohdify. Filter off the crystalline aldoxime at the pump, wash well with cold water, and dry in the air upon filter paper. The yield of veratraldoxime is 88 g. 

Method 1. Dissolve 25 0 g. of salicylaldehyde (Section IV,122) in 215 ml. of 2N sodium hydroxide solution, add 12 05 g. of hydroxylamine hydrochloride, and warm the mixture for 30 minutes on a water bath. Acidify with acetic acid and cool in ice the salicylaldoxime separates as a congealed oil. Recrystalhae from chloroform - light petroleum (b.p. 40-60°). The yield of salicylaldoxime (colourless crystals, m.p. 57°) is 5 g. 

In a 250 ml. bolt-head flask, fitted with a reflux condenser, place a mixture of 10 g. of benzoin (Section IV,125) and 20 g. (25 ml.) of rectified spirit together with an aqueous solution of 8 0 g. of hydroxylamine hydrochloride which has previously been neutralised with 4-4 g. of sodium hydroxide. Reflux for 60 minutes. Add water to precipitate the benzoinoxime, and cool in an ice bath. Filter the solid with suction at the pump, wash it with water, and recrystaUise from dilute alcohol. Alternatively, the dry sohd may be recrystalhsed from ether. The yield of pure a-benzoinoxime, m.p. 151°, is 5 g. 

The use of oximes as nucleophiles can be quite perplexing in view of the fact that nitrogen or oxygen may react. Alkylation of hydroxylamines can therefore be a very complex process which is largely dependent on the steric factors associated with the educts. Reproducible and predictable results are obtained in intramolecular reactions between oximes and electrophilic carbon atoms. Amides, halides, nitriles, and ketones have been used as electrophiles, and various heterocycles such as quinazoline N-oxide, benzodiayepines, and isoxazoles have been obtained in excellent yields under appropriate reaction conditions. 

The secondary allylic methylamine 324 can be prepared by the allylation of A -methylhydroxylamine (323), followed by hydrogenolysis[201], Monoallylation of hydroxylamine, which leads to primary allylamines, is achieved using the jV,0-bis-Boc-protected hydroxylatnine 326. N -... 

The purity of a synthetic preparation of methylethyl ketone (C4H8O) can be determined by reacting the ketone with hydroxylamine hydrochloride, liberating HCl (see Table 9.10). In a typical analysis, a 3.00-mL sample was diluted to 50.00 ml and treated with an excess of hydroxylamine hydrochloride. The liberated HCl was titrated with 0.9989 M NaOH, requiring 32.68 ml to reach the end point. Report the percent purity of the sample, given that the density of methylethyl ketone is 0.805 g/mL. 

Explain why strong oxidizing agents interfere with this analysis and why an excess of hydroxylamine prevents such interferences from occurring. 

This reaction, conducted in alkaline solution, also produces carboxyl groups by hydrolysis of the amide (54). Recent work on the reaction of polyacrylamide with hydroxylamine indicates that maximum conversion to the hydroxamate fiinctionahty (—CONHOH) takes place at a pH > 12 (57). Apparendy, this reaction of hydroxylamine at high pH, where it is a free base, is faster than the hydrolysis of the amide by hydroxide ion. Previous studies on the reaction of hydroxylamine with low molecular weight amides indicated that a pH about 6.5 was optimum (55). 

An additional mole of ammonium sulfate per mole of final lactam is generated duting the manufacture of hydroxylamine sulfate [10039-54-0] via the Raschig process, which converts ammonia, air, water, carbon dioxide, and sulfur dioxide to the hydroxylamine salt. Thus, a minimum of two moles of ammonium sulfate is produced per mole of lactam, but commercial processes can approach twice that amount. The DSM/Stamicarbon HPO process, which uses hydroxylamine phosphate [19098-16-9] ia a recycled phosphate buffer, can reduce the amount to less than two moles per mole of lactam. Ammonium sulfate is sold as a fertilizer. However, because H2SO4 is released and acidifies the soil as the salt decomposes, it is alow grade fertilizer, and contributes only marginally to the economics of the process (145,146) (see Caprolactam). 

A number of substances, such as the most commonly used sulfur dioxide, can reduce selenous acid solution to an elemental selenium precipitate. This precipitation separates the selenium from most elements and serves as a basis for gravimetry. In a solution containing both selenous and teUurous acids, the selenium may be quantitatively separated from the latter by performing the reduction in a solution which is 8 to 9.5 W with respect to hydrochloric acid. When selenic acid may also be present, the addition of hydroxylamine hydrochloride is recommended along with the sulfur dioxide. A simple method for the separation and deterrnination of selenium(IV) and molybdenum(VI) in mixtures, based on selective precipitation with potassium thiocarbonate, has been developed (69). 

The reaction of )3-substituted vinyl ketones RCOCH=CHY (Y = halogen, OR or NR2) with hydroxylamine hydrochloride has been extensively investigated (63AHC(2)365, 62HC(l7)l). One would anticipate that replacement of hydroxylamine hydrochloride with hydroxylamine in these reactions would result in enhanced regiospecificity and increased... 

The reaction of hydroxylamine with 2-substituted chromones (392) where R = Me, Ph (76MI41601) or CO2H (79MI41600) gave exclusively 5-(o-hydroxyphenyl)isoxazoles (393). 

The nucleophilic attack of hydroxylamine at the 5-position of 4-trifluoroacetyloxazoles (414) led to a mixture of stereoisomeric isoxazolines (415). Dehydration of these isomeric isoxazolines (415) in the presence of trifluoroacetic anhydride gave isoxazoles (416) in good yields (76JHC825). 

The treatment of 3-acylisoxazoles (438) with hydroxylamine hydrochloride gives furazan ketones (439). On the other hand, furazan ketones (439) rearrange to 3-acylisoxazoles (438) with a loss of hydroxylamine under the influence of a mineral acid. Thus, by refluxing phenacylphenylfurazan with concentrated alcoholic hydrogen chloride, 3-benzoyl-5-phenyl-isoxazole is formed similarly, phenyl(phenacylphenyl)furazan gives 3-benzoyl-3,5-diphenyl-isoxazole (62HC(17)1, p. 35). 

Methylisoxazole and its homologs have been readily prepared by reaction of hydroxylamine hydrochloride with tetraalkoxypropanes (284) (63AHC(2)365), a-alkyl- 8-alkoxy-acroleins (62ZOB2961) and with a-alkyl- -dimethylaminoacroleins (60CB1208). 

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