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Homogeneous reactions of supercritical water

Homogeneous reactions carried out in supercritical fluids are reactions in supercritical water, organo-metallic reactions and Diels Alder reactions. Reactions in supercritical water are well studied and will be described in the following section. [Pg.1447]

Examples of tire homogeneous reactions are given in Table 21.1.11. In some of the reactions discussed in this category, acid or base catalysts were used to enhance the rates.  [Pg.1447]

Conversion of tert-butyl alcohol to isobutylene None/H2S04/NaOH [Pg.1448]

Dehydration of cyclohexanol, 2-methyl cyclohexanol, 2-phenylethanol Acid [Pg.1448]

The use of supereritieal fluids as reaetion media for organometallic species has also been investigated. Reaetions inelude photoehemieal replaeement of carbon monoxide with Nj and Hj in metal earbonyls, where the reaetion medium is supercritical xenon. Also, photochemical activation of C-H bonds by organometallic complexes in supercritical carbon dioxide has also been investigated. More recent studies on photochemical reactions also include laser flash photolysis of metal carbonyls in supercritical carbon dioxide and ethane and laser flash photolysis of the hydrogen abstraction reaction of triplet benxophenone in supercritical ethane and CHF3. [Pg.1448]


Examples of the homogeneous reactions in supercritical water are included in Table 2. Use of acid or base catalysts enhances the rates of some of the... [Pg.2922]

In the wet oxidation process, materials partially or completely dissolve into a homogeneous, condensed-phase mixture of oxygen and water, and chemical reactions between the material and oxygen take place in the bulk water phase. This condensed-phase makes wet oxidation an ideal process to transform materials which would otherwise be non-soluble in water to a harmless mixture of carbon dioxide and water. Since oxidation reactions are also exothermic, the high thermal mass of supercritical water makes this reaction medium better suited for thermal control, reactor stability, and heat dissipation. The purpose of this research was to establish a new method for selectively oxidizing waste hydrocarbons into new and reusable products. [Pg.439]

In a very early study Patat (1945) investigated the hydrolysis of aniline to phenol in a water-based acidic solution in near-critical and supercritical water (Tc = 374.2°C, Pc = 220.5 bar). Phosphoric acid and its salts are used as the catalyst for this reaction. The reaction proceeds extremely slowly under normal conditions and reaches equilibrium at low conversion levels. For these reasons, Patat chooses to study the reaction in supercritical water to temperatures of 450°C and to pressures of 700 bar in a flow reactor. He finds that the reaction follows known, regular kinetics in the entire temperature and pressure space studied and the activation energy of the hydrolysis (approximately 40 kcal/mol) is the same in the supercritical as well as in the subcritical water. He suggests that the reaction is catalyzed by hydrogen ions formed from dissolution of phosphoric acid in supercritical steam. Very small amounts of phosphoric acid and the salts of the phosphoric acid are dissolved in the supercritical steam and are split into ions. Patat lists several dissolution constants for primary ammonium phosphates in supercritical steam. In this instance, the reaction performance is improved when the reaction is operated homogeneously in the mixture critical region and, thus, in intimate contact between the reactants and the catalyst. [Pg.328]

The ability to functionalize DENs allows their use as homogeneous catalysts in a variety of reaction media including water, organic solvents, supercritical CO2, and biphasic fluorous solvents. Pd DENs have been the most widely studied homogeneous... [Pg.97]

Reactions that otherwise would be carried out in more than one phase (heterogeneous reactions) can be transformed to homogeneous ones, with the aid of supercritical fluids, where interphase transport limitations are eliminated. This is realized due to enhanced solubilities of the supercritical fluids. Typical examples are reactions in water (supercritical water can solubilize organic compounds), homogeneous catalytic reactions, reactions of organometallic compounds. Homogenizing one compound more than the other may also affect relative rates in complex reactions and enhance the selectivity. [Pg.2918]


See other pages where Homogeneous reactions of supercritical water is mentioned: [Pg.2922]    [Pg.1447]    [Pg.1447]    [Pg.1447]    [Pg.1447]    [Pg.1699]    [Pg.971]    [Pg.971]    [Pg.2922]    [Pg.1447]    [Pg.1447]    [Pg.1447]    [Pg.1447]    [Pg.1699]    [Pg.971]    [Pg.971]    [Pg.3]    [Pg.399]    [Pg.606]    [Pg.393]    [Pg.53]    [Pg.423]    [Pg.197]    [Pg.168]    [Pg.432]    [Pg.2008]    [Pg.263]    [Pg.132]    [Pg.1]    [Pg.438]    [Pg.438]    [Pg.395]    [Pg.36]    [Pg.510]    [Pg.131]    [Pg.4]    [Pg.149]    [Pg.295]    [Pg.121]    [Pg.646]    [Pg.337]    [Pg.57]    [Pg.383]    [Pg.237]    [Pg.9]    [Pg.206]    [Pg.2919]    [Pg.2921]    [Pg.2922]    [Pg.391]    [Pg.39]    [Pg.688]   


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Homogeneous reactions

Homogenous reactions

Reaction homogeneous reactions

Supercritical water

Supercritical water reactions

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