Hydroxylamine developer

Effect of Sulfite upon Hydroxylamine Development NH2OH, 0.04 M pH, 10.8 excess Br, 0.00067 M... 

A number of cyclic imides, such as uracil (11), can be used in conjunction with a nitrogenous base.64 These compounds are added to hydroxylamine developer formulations. Several thioether-substituted 2,4- or 4,6-dihydroxypyrimidines, such as (12), are useful.65 Thioether-con-taining carboxylic acids can be used in the preparation of electrically conducting transferred silver images. These include 3-thiapentanoic acid, 3-thiapentanedioic acid and 3,6-dithiaoctanedioic acid.66 Mercaptobenzoic acids are used alone or with a cyclic imide solvent to produce lithographic... 

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. 

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. 

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). 

YeUowing of wool can occur during dyeing, depending on pH, temperature and time, and chlorinated wools ate especially sensitive. Bleaching agents that can be added to the dyebath have been developed based on sodium bisulfite and hydroxylamine sulfate (108). Addition of hydrogen peroxide to the dyebath after exhaustion can also be effective. 

Dutch State Mines (Stamicarbon). Vapor-phase, catalytic hydrogenation of phenol to cyclohexanone over palladium on alumina, Hcensed by Stamicarbon, the engineering subsidiary of DSM, gives a 95% yield at high conversion plus an additional 3% by dehydrogenation of coproduct cyclohexanol over a copper catalyst. Cyclohexane oxidation, an alternative route to cyclohexanone, is used in the United States and in Asia by DSM. A cyclohexane vapor-cloud explosion occurred in 1975 at a co-owned DSM plant in Flixborough, UK (12) the plant was rebuilt but later closed. In addition to the conventional Raschig process for hydroxylamine, DSM has developed a hydroxylamine phosphate—oxime (HPO) process for cyclohexanone oxime no by-product ammonium sulfate is produced. Catalytic ammonia oxidation is followed by absorption of NO in a buffered aqueous phosphoric acid... 

The major development in the Knorr pyrrole synthesis has been access to the amine component. For example, use of preformed diethyl aminomalonate with 1,3-diketones affords much higher yields of pyrroles 14. Reaction of 6-dicarbonyl compounds with hydroxylamine 0-sulfonic acid gives pyrroles 15 in one step. Weinreb a-aminoamides have found use in the Knorr pyrrole synthesis of a wide variety of pyrroles 16. °... 

Two hydrogen-transfer systems have been developed that also give good yields of hydroxylamines. One uses 5% palladium-on-carbon in aqueous tetrahydrofuran with phosphinic acid or its sodium salt as hydrogen donor the other uses 5% rhodium-on-carbon in aqueous tetrahydrofuran and hydrazine as donor. These systems are complementary and which is the better may depend on the substrate (36). The reductions cannot be followed by pressure drop, and both require analysis of the product to determine when the reduction should be terminated. 

Phenylhydroxylamine rearranges in sulfuric acid to give mainly p-aminophenol. Industrial routes to this compound have been developed in which phenylhydroxylamine, formed by hydrogenation of nitrobenzene in sulfuric acid over platinum-on-carbon, is rearranged as it is formed. Conditions are adjusted so that the rate of rearran ment is high relative to the rate of hydrogenation of hydroxylamine to aniline (15,17,86). An easy way to obtain a favorable rate ratio is to carry out the reduction with about 1% DMSO present in the sulfuric acid (79,81). 

Procedure The sodium hydroxide is dissolved in 200 ml water and the benzaldehyde is added. With continued stirring the hydroxylamine hydrochloride is added in portions. Some heat is developed and eventually the benzaldehyde dissolves. The solution is stirred for 15 minutes and then cooled in an ice-bath. A waxy, crystalline mass separates, and after further cooling it is collected by suction and dried in air. Yield is B6 to 149 grams. This crude material is suitable for step (B). 

Various initiation strategies and surfactant/cosurfactant systems have been used. Early work involved in situ alkoxyamine formation with either oil soluble (BPO) or water soluble initiators (persulfate) and traditional surfactant and hydrophobic cosurfactants. Later work established that preformed polymer could perform the role of the cosurfactant and surfactant-free systems with persulfate initiation were also developed, l90 222,2i3 Oil soluble (PS capped with TEMPO,221 111,224 PBA capped with 89) and water soluble alkoxyamines (110, sodium salt""4) have also been used as initiators. Addition of ascorbic acid, which reduces the nitroxide which exits the particles to the corresponding hydroxylamine, gave enhanced rates and improved conversions in miniemulsion polymerization with TEMPO.225 Ascorbic acid is localized in the aqueous phase by solubility. 

Degussa has done extensive work to develop highly active catalysts for the prodnction of hydroxylamine in this process. 

New developments are hydroxylamines and lactones (for processing stability), which operate at an earlier stage during stabilisation. Lactone (benzofuranone) chemistry has been identified as commercially viable, and marks a revolutionary advance in comparison to hindered phenols and phosphites [18]. New lactone chemistry (Figure 10.1) provides enhanced additive compatibility, reduced taste and odour (organoleptics), resistance to irradiation-induced oxidation, and inhibition of gas fade discoloration. The commercial introduction of fundamentally new types of stabilisers for commodity and engineering polymers is not expected in the near future. 

Stockman and coworkers [329] developed a straightforward synthesis of a tricyclic compound 2-636 which has some resemblance to the spirocyclic portion of the natural product halichlorine (2-637) [330]. On treatment of the symmetrical ketone 2-633, accessible in five steps from alcohol 2-632, with hydroxylamine hydrochloride the spiro piperidine 2-636 could be obtained in 62% yield (Scheme... 

Very recently, Dongol and coworker have developed a one-pot synthesis of isoxa-zolidinones starting from O-homoallyl hydroxylamines and aryl halides. After a Heck reaction of the substrates, a subsequent C-N bond formation took place to furnish the target compounds in up to 79% yield [86]. 

Kundu et al. developed a mild and efficient one-pot protocol for the synthesis of dihydroindazoloisoquinolines 142 via an unprecedented SnCl2-mediated intramolecular cyclization of nitro-aryl substrates 143 <06OL1525>. As illustrated below, the cyclization occurs via the hydroxylamines 144 and leads to the formation of dihydroindazoloisoquinolines 142 in high yield and purity. 

Analyze the NHS-palmitate for purity using TLC on silica plates. Develop using a solvent mixture of chloroforrmpetroleum diethyl ether (bp 40-60°C) of 8 2. Excess NHS and NHS-palmitate may be detected by staining with 10 percent hydroxylamine in 0.1 N NaOH, followed after 2 minutes by a 5 percent solution of FeCl3 in 1.2 N HC1 (creates red colored spots). 

To undertake oxidation of both cyclic and acyclic hydroxylamines to nitrones, an electrochemical oxidative system has been developed, where WC>42-/WC>52-are used as cathodic redox mediators and Br /Br2 or I—/I2 as anodic redox mediators (129-131). 

HPO [Hydroxylamine phosphate oxime] A process for making caprolactam, an intermediate in the manufacture of polyamides. It differs from related processes, such as HSO, in producing less of the ammonium sulfate by-product. Developed by DSM Research, The Netherlands, operated by DSM Polymers and Hydrocarbons, and offered for license by Stamicarbon. 

Over the past decade, the semiconductor manufacturing industry has used hydroxylamine solutions in cleaning formulations to strip process residues from integrated circuit devices. Hydroxylamine and its derivatives are also used in the manufacture of nylon, inks, paints, pharmaceuticals, agrochemicals, and photographic developers. 

CSI began development of its own hydroxylamine production process through laboratory-scale experimentation in 1997. Development continued with the construction of a 10 gal pilot plant, which was operational in early 1998. In July 1998, CSI leased approximately 20,000 square feet in a multiple-tenant building and began to set up the production facility. 

These reagents are required for proper color development. Hydroxylamine hydrochloride is a reducing agent, which is required to keep the iron in the +2 state. The o-phenanthroline is a ligand that reacts with Fe2+ to form an orange-colored complex ion. This ion is the absorbing species. In addition, since the reaction is pH dependent, sodium acetate is needed for buffering at the optimum pH. 

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