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Alkaline oxidation

Oxidation, already described in neutral and acidic media, may also be performed in basic medium. An alkaline solution of H2O2 reacts with 4-thiazoline 2-thione to yield thiazole-2-sulfonic acid (201-203), whereas alkaline oxidation performed with (NH )2S20g yields the disulfides (148). [Pg.397]

Organic tellurium compounds and siliceous materials, ie, rock, ore, or concentrates, are fused with mixtures of sodium carbonate and alkaline oxidants, ie, sodium peroxide, potassium nitrate, or potassium persulfate. For volatile compounds, this fusion is performed in a bomb or a closed-system microwave digestion vessel. An oxidising fusion usually converts tellurium into Te(VI) rather than Te(IV). [Pg.388]

Solutions of HEC are pseudoplastic. Newtonian rheology is approached by very dilute solutions as well as by lower molecular-weight products. Viscosities change Httie between pH 2 and 12, but are affected by acid hydrolysis or alkaline oxidation under pH and temperature extremes. Viscosities of HEC solutions change reversibly with temperature, increasing when cooled and decreasing when warmed. [Pg.274]

Refactory ceramic fibres or special purpose fibres, with the exception of those specified elsewhere in the Approved Supply List (man-made vitreous (silicate) fibres with random orientation with alkaline oxide and alkali earth oxide (Na20 + K2O + CaO + MgO + BaO) content less than or equal to 18% by weight)... [Pg.95]

With the development of HPLC, a new dimension was added to the tools available for the study of natural products. HPLC is ideally suited to the analysis of non-volatile, sensitive compounds frequently found in biological systems. Unlike other available separation techniques such as TLC and electrophoresis, HPLC methods provide both qualitative and quantitative data and can be easily automated. The basis for the HPLC method for the PSP toxins was established in the late 1970 s when Buckley et al. (2) reported the post-column derivatization of the PSP toxins based on an alkaline oxidation reaction described by Bates and Rapoport (3). Based on this foundation, a series of investigations were conducted to develop a rapid, efficient HPLC method to detect the multiple toxins involved in PSP. Originally, a variety of silica-based, bonded stationary phases were utilized with a low-pressure post-column reaction system (PCRS) (4,5), Later, with improvements in toxin separation mechanisms and the utilization of a high efficiency PCRS, a... [Pg.66]

Ferricyanide oxidation of 1,5-disubstituted thiocarbazones (116) give the mesoionic tetrazolium salts (117) under mild conditions (Eq. 21).190 This is in contrast to the strongly alkaline oxidation of carbazides leading to mercapto formazans as shown in Eq. 8 (Section 7.3.1.4). The heterocyclic triazine (118), obtained by the action of a diazonium salt on 2-... [Pg.235]

The desizing of water-soluble size polymers can be summarised as follows. Batchwise or continuous methods can be used in both cases an adequate supply of hot water is needed during the washing-off. Hot water and detergent are needed to remove polyfvinyl alcohol) or carboxymethylcellulose. The addition of alkali may be beneficial with carboxymethylcellulose. Alkali is essential with modified starches and acrylic acid copolymers. Polyfvinyl alcohol) can be degraded effectively by alkaline oxidation. [Pg.107]

As a safer alternative to digestion of vegetable matter with perchloric acid, alkaline oxidation of sulfur compounds to sulfate by sodium hypobromite, and reduction of sulfate to hydrogen sulfide by hydriodic acid/formaldehyde/phosphinic acid is recommended. [Pg.1364]

For analysis in solutions, the most frequently used CL reaction is alkaline oxidation of luminol and lucigenin in the presence of hydrogen peroxide as oxidant, although sodium hypochlorite, sodium perborate, or potassium ferricyanide may also be used. CL reactions involving alkaline oxidation have been used to indicate acid-base, precipitation, redox, or complexometric titration endpoints either by the appearance or the quenching of CL when an excess of titrant is present [114, 134], An example of these mechanisms is shown in Figure 14. [Pg.24]

Treatment of the optically active gem-borazirconocene alkanes with deuterium oxide followed by alkaline oxidation affords the corresponding optically active 1-deuterio primary alcohols. The enantiomeric excess of the resulting primary alcohols represents the diaster-eoselectivity of the asymmetric hydrozirconation (Scheme 7.13). Based on the cost and availability of optically active ligands, three types were explored monoterpenes, 1,2-diols, and 1,2-amino alcohols. Hydrozirconation of optically pure 1-alkenyl boranes 39 provided optically active 1,1-bimetallics 40. [Pg.245]

Based on reaction (7), overall analysis for alkyl groups (alkaline oxidation and alcohol ratio determination) and ratio k, k6 k-, — 3 2 1 (assumed because k2 k3 k4 =3 2 1). [Pg.236]

Smith, D. G., and A. C. Neish Alkaline Oxidation of C-Labellcd Protolignin Formed from Cinnamic Acid in Spruce and Aspen Twigs. Phytochem. 3, 609—616 (1964). [Pg.158]

Reagents to carry out the alkaline oxidation of the toxins were prepared as originally described ( ) with the exception that nitric acid was used in place of acetic acid. The reagent concentrations and flow rates are shown in Table I. [Pg.201]

Conjugate addition of methanol to a,/l-unsaturated carbonyl compounds forms a new carbon-oxygen bond to yield valuable ethers (Scheme 26). Kabashima et al. (12) reported the conjugate addition of methanol to 3-buten-2-one on alkaline oxides, hydroxides, and carbonates at a temperature of 273 K. The activities of the catalyst follow the order alkaline earth metal oxides > alkaline earth metal hydroxides > alkaline earth metal carbonates. All alkaline earth metal oxides exhibited high catalytic activities and, as in alcohol condensations and nitroaldol reactions, their catalytic activities were not much affected by exposure to CO2 and air. [Pg.266]

The most common method used to synthesize the diazafluorenes is by alkaline oxidation of phenanthrolines <1996CHEC-II(7)921>. For example, Gusak a a/, have shown that compounds such as 87 can be converted into the corresponding diazafluorenones using potassium hydroxide and potassium permanganate (Equation 23) <2004RJ01322>. [Pg.1247]

At neutral pH adrenaline was oxidized first to adrenochrome and then to melanin different products were produced at alkaline pH and melanin formation was low. With noradrenaline similar processes took place at neutral pH, but at a slower rate in this case the alkaline oxidation was characterized by increased melanin formation.61... [Pg.214]


See other pages where Alkaline oxidation is mentioned: [Pg.87]    [Pg.163]    [Pg.27]    [Pg.1050]    [Pg.193]    [Pg.539]    [Pg.542]    [Pg.22]    [Pg.134]    [Pg.93]    [Pg.106]    [Pg.446]    [Pg.297]    [Pg.265]    [Pg.14]    [Pg.245]    [Pg.245]    [Pg.159]    [Pg.18]    [Pg.433]    [Pg.77]    [Pg.263]    [Pg.120]    [Pg.185]    [Pg.317]    [Pg.1261]    [Pg.137]    [Pg.628]    [Pg.558]    [Pg.117]    [Pg.93]    [Pg.85]    [Pg.456]   
See also in sourсe #XX -- [ Pg.499 ]

See also in sourсe #XX -- [ Pg.55 , Pg.141 , Pg.145 , Pg.150 , Pg.179 ]




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Activity of Alkaline Earth Metal Oxides

Alkali and alkaline earth metals oxides

Alkaline Dehydration, Fragmentation, and Oxidation Reactions of Carbohydrates

Alkaline Earth Metal Oxides Doped with Alkali Metals Prepared by Impregnation

Alkaline bromate oxidation with

Alkaline cellulose, oxidation

Alkaline cupric oxide

Alkaline cupric oxide oxidation method

Alkaline diperiodatocuprate oxidant

Alkaline earth (group oxidation number

Alkaline earth and group IV oxides

Alkaline earth metal complexes phosphine oxides

Alkaline earth metal oxides catalytic activity

Alkaline earth metal oxides deposition

Alkaline earth metal oxides doped with alkali metals prepared

Alkaline earth metal oxides impregnation

Alkaline earth metal oxides modified with

Alkaline earth metal oxides optimization

Alkaline earth metal oxides reactions

Alkaline earth metal oxides with high-surface-area

Alkaline earth metals oxidation number

Alkaline earth metals oxides

Alkaline earth oxide study

Alkaline earth oxides

Alkaline earth oxides cubic structure

Alkaline earth oxides surface reactivity

Alkaline earth oxides, acetone condensation

Alkaline media electrocatalytic oxidation

Alkaline media electrochemical oxidation

Alkaline media ethylene glycol oxidation

Alkaline metal oxide

Alkaline oxides

Alkaline oxides, thermodynamics

Alkaline permanganate oxidation

Alkaline permanganate oxidation with

Alkaline-earth oxides absorption bands

Alkaline-earth oxides powders

Alkaline-earth oxides single crystals

Alkenes oxidation with alkaline hydrogen peroxide

Catalysis on alkaline earth metal oxides

Complex oxides alkaline-earth

Crystalline alkaline-earth metal oxides

Determination of total and organic phosphorus by alkaline persulphate oxidation

Ferricyanide oxidations, alkaline

High-surface-area alkaline earth metal oxides

Hydroboration/alkaline oxidation

Lignin alkaline oxidation

Methanol oxidation reaction alkaline media

Nitrous oxide alkaline solutions

Oxidation alkaline glycerol

Oxidation in Alkaline Solution

Oxidation states alkaline earth metals

Oxidation with Alkaline Hydrogen Peroxide

Oxidative decarboxylation with alkaline

Oxide solubilities in melts based on alkali- and alkaline-earth metal halides

Oxides of alkaline-earth metals

Oxirane oxidation with alkaline hydrogen peroxide

Passivity anodic oxidation, alkaline solutions

Polysaccharides oxidative alkaline degradation

Process for the Alkaline Oxidative Degradation of Reducing Sugars

Regularities of oxide solubilities in melts based on alkali and alkaline-earth metal halides

Studies of Alcohol Oxidation on Pd-Electrodes in Alkaline Media

Sugars, alkaline degradation oxidation

Synthesis of High-Surface-Area Alkaline Earth Metal Oxides

The Alkaline-Earth Oxides, Sulfides, Selenides, and Tellurides

Zeolites and Mesoporous Aluminosilicates Modified with Alkaline Earth Metal Oxides

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