Chemical selective oxidation

The high fluorine content contributes to resistance to attack by essentially all chemicals and oxidizing agents however, PCTFE does swell slightly ia halogenated compounds, ethers, esters, and selected aromatic solvents. Specific solvents should be tested. PCTFE has the lowest water-vapor transmission rate of any plastic (14,15), is impermeable to gases (see also Barrierpolymers), and does not carbonize or support combustion. 

Cyanide Wastes. Ozone is employed as a selective oxidant in laboratory-scale synthesis (7) and in commercial-scale production of specialty organic chemicals and intermediates such as fragrances, perfumes (qv), flavors, antibiotics (qv), hormones (qv), and vitamins (qv). In Japan, several metric tons per day (t/d) of piperonal [120-57-0] (3,4-methylenedioxybenzaldehyde) is manufactured in 87% yield via ozonolysis and reduction of isosafrole [93-16-3], Piperonal (or heHotropine [120-57-0]) has a pleasant odor and is used in perfumery. Oleic acid [112-80-1/, CH3(CH2 )7CH—CH(CH2 ). C02H, from tall oil (qv) is ozonated on a t/d scale to produce pelargonic, GgH2yG02H, and azelaic, H02G(GH2)yG02H, acids. Oleic acid also is ozonated in Japan... 

Snatzke has found that a solution prepared from chromium trioxide and dimethylformamide with a small amount of sulfuric acid has similar chemical properties as the Sarett reagent. It is useful with acid sensitive compounds and oxidation occurs at such a moderate rate that selective oxidations are often possible. Although the position allylic to a A -double bond is not attacked, the 3-hydroxy-A -system cannot be oxidized satisfactorily to the cor-... 

Finally, if only the -CH2OH end of the aldose is oxidized without affecting the -CHO group, the product is a monocarboxylic acid called a uronic acid. The reaction must be done enzymatically no satisfactory chemical reagent is known that can accomplish this selective oxidation in the laboratory. 

Qean and efficient processes production of at) mc chemicals witiiout salt, replaconent of HE or H2SO4, catalytic combustion, hi tempoature selective oxidation firel cells ... 

New materials are also finding application in the area of catalysis reiated to the Chemicals industry. For example, microporous [10] materials which have titanium incorporated into the framework structure (e.g. so-calied TS-1) show selective oxidation behaviour with aqueous hydrogen peroxide as oxidizing agent (Figure 5). Two processes based on these new catalytic materials have now been developed and commercialized by ENl. These include the selective oxidation of phenol to catechol and hydroquinone and the ammoxidation of cyclohexanone to e-caproiactam. 

There is not much to be said about the use of micro reactors for bulk chemicals and commodities. Worz et al. are so far the only ones who have disclosed their work on the potential of micro-structured reactors for the optimization of chemical processes performed on a large scale ofindustrial relevance [110,112,154,288-290]. This included a fast exothermic liquid/liquid two-phase reaction, which was used for the industrial production of a vitamin intermediate product, and a selective oxidation reaction for an intermediate, a substituted formaldehyde derivative. 

The reaction is carried out using a titanium silicalite-1 (TS-1) zeolite catalyst [30, 122]. This type of catalyst is known to accelerate the selective oxidation of alcohols, epoxidation of alkenes and hydroxylation of aromatics. These reactions have importance for fine-chemical production. 

S. T. Oyama and J. W. Hightower (eds), Catalytic Selective Oxidation, ACS Symposium Series, Vol. 523, American Chemical Society, Washington, DC, 1992. 

Selective staining of polysaccharide in the cell is said to depend upon the oxidizing action of periodate on such chemical configurations as a, p glycols and a-hydroxyketones. Polyaldehydes generated by this selective oxidation react with sulfite-decolorized fuchsin. Polysaccharide areas in the cell are colored red by the stain. 

Compared with ketoreductases, the synthetic application of alcohol oxidases has been less explored. However, selective oxidation of primary alcohols to aldehydes is superior to the chemical methods in terms of conversion yields, selectivity, and environmental friendliness of reaction conditions. In addition, coupling of alcohol oxidase with other enzymes provides a tremendous opportunity to develop multi-enzyme processes for the production of complex molecules. Therefore, a growing impact of alcohol oxidases on synthetic organic chemistry is expected in the coming years. 

Sheth SR, Efremova NV, Leckband DE (2000) Interacitons of poly(ethylene oxide) brushes with chemically selective surfaces. J Phys Chem B 104 7652-7662... 

Metal complexes, especially involving transition metals, are known for their role as catalysts in a broad variety of chemical processes including isomerization, oxidization, hydrogenation, and polymerization. Such catalytic reactions play an important role not only in many industrial processes, such as petroleum and polymer industries, but also in many biological systems, e.g., a variety of selective oxidation catalysts with heme (1) and nonheme (2) iron centers. The transition metals in these systems usually constitute a fundamental part of the catalyst, due to their... 

The selective oxidation of ra-butane to give maleic anhydride (MA) catalyzed by vanadium phosphorus oxides is an important commercial process (99). MA is subsequently used in catalytic processes to make tetrahydrofurans and agricultural chemicals. The active phase in the selective butane oxidation catalyst is identified as vanadyl pyrophosphate, (V0)2P207, referred to as VPO. The three-dimensional structure of orthorhombic VPO, consisting of vanadyl octahedra and phosphate tetrahedra, is shown in Fig. 17, with a= 1.6594 nm, b = 0.776 nm, and c = 0.958 nm (100), with (010) as the active plane (99). Conventional crystallographic notations of round brackets (), and triangular point brackets (), are used to denote a crystal plane and crystallographic directions in the VPO structure, respectively. The latter refers to symmetrically equivalent directions present in a crystal. 

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