Catalytic test for

Catalytic Testing for NMP Synthesis - Continuous Flow Reactor... 

The obtained samples were characterized by means of XRD, IR, SEM, adsorption and catalytic tests for cyclohexene oxidation. 

The catalytic tests for cyclohexene oxidation were performed at 60°C in glass vials for 20 hours. The evacuated samples (0.05g) were immersed in mixture of cyclohexene (0.04ml), methanol (0.42ml) and 30% hydrogen peroxide (0.04ml). 

Catalytic tests for cyclohexene oxidation show some activity of SnAlPO, which can be increased by cation-exchange modification. Cyclohexenone is a predominant reaction product. The difference between activity of SnAlPO and AlPO-5 is not very substantial, which is rather surprising. Considering the presence of tin and the transition metal cation, one could expect higher activity for oxidation reaction. Other catalytic investigations are under way and will be published [7]. 

The solids have been prepared by solid-state reaction in air, of pure V(V), Sb(III) y Ti(IV) oxides. Fresh samples have been characterised by Temperature programmed reduction (TPR) and catalytic tests. For Vo 8SbTio.204 catalysts, elemental C-H-N-O analysis was performed on fresh and used samples. 

These methods suffer from the lack of complementarity, and thus the significance of results provided by any of them is limited. A standard practice to detect the Bronsted or Lewis character of surface sites is pyridine adsorption combined with FTIR measurements the number of Lewis or Bronsted sites is more difficult to count, however. Other titration methods use either color indicators and acid or base titrants in nonpolar solvents or the adsorption of gaseous acidic or basic probes. They do not, in general, give consistent quantitative information about the number of acid or base sites even when applied to the same sample. There are several reasons the applicability of titration methods is limited Either the state of the surface is different for different methods or adsorption equilibrium is not always achieved. Another more serious source of discrepancies between titration methods is that probe molecules of different basicities "see" different surface sites. The lack of a uniquely defined thermodynamic scale of acid strength of surface sites makes difficult any correlation between results obtained with different probe molecules. The use of standard catalytic tests for probing the so-called catalytic acidity is not always a better approach, because the mechanistic assumptions involved are neither straightforward nor subject to experimental proof. 

TABLE 7.1 Catalytic Tests for the Competitive Coupling of Pairs of Amines with one Acid and Pairs of Acids with one Amine Mediated by the Carbodiimide Cationic Condensing Agent in the Presence or Absence of the Hexameric Capsule as Supramolecular Nanoreactor at 60°C, Time 18 h. + Presence Absence... 

Nitrates may not be present in the catalytic test for molybdenum, since... 

The specific and sensitive catalytic test for silver can also be used to detect the latter in the mixture of precipitates formed by hydrochloric acid in the course of the systematic qualitative scheme. The precipitate, possibly containing chlorides of Ag, Hg, Pb, Tl, is washed with hot water, and a small portion heated in a micro crucible to weak glowing, to remove the HgaClj and TlCl. The residue in the crucible is treated, after cooling, with 1-2 drops of the Mn or the Ce solution. ... 

Dimitratos, N., Porta, F. and Prati, L. (2005). Au, Pd (Mono and Bimetallic) Catalysts Supported on Graphite Using the Immobihsation Method - Synthesis and Catalytic Testing for Liquid Phase Oxidation of Glycerol, Appl Catal A Gen., 291, pp. 210-214. 

Detecting the presence of small, even invisible, amounts of blood is routine. Physical characteristics of dried stains give minimal information, however, as dried blood can take on many hues. Many of the chemical tests for the presence of blood rely on the catalytic peroxidase activity of heme (56,57). Minute quantities of blood catalyze oxidation reactions between colorless materials, eg, phenolphthalein, luco malachite green, luminol, etc, to colored or luminescent ones. The oxidant is typically hydrogen peroxide or sodium perborate (see Automated instrumentation,hematology). 

PMo220 4q, is analytically usehil, being formed in the molybdenum test for phosphate ion. Poly- and heteropolymolybdate ions are used in the precipitation of dyes. The protonated forms of the ions are strongly acidic and many poly- and heteropolymolybdate compounds have catalytic activity that is attributable to their acid—base or redox properties. 

PMc3 to give the complex salts 21 as shown in Scheme 12. Compounds of type 20 and 21 have successfully been tested for their catalytic efficiency. However, it was observed that fBuaPNSiMea failed to show similar adduct formation and this failure was attributed to steric crowding. 

In the enzyme design approach, as discussed in the first part of this chapter, one attempts to utilize the mechanistic understanding of chemical reactions and enzyme structure to create a new catalyst. This approach represents a largely academic research field aiming at fundamental understanding of biocatalysis. Indeed, the invention of functional artificial enzymes can be considered to be the ultimate test for any theory on enzyme mechanisms. Most artificial enzymes, to date, do not fulfill the conditions of catalytic efficiency and price per unit necessary for industrial applications. 

Ghosh et al. [70] reviewed a few years ago the utihty of C2-symmetric chiral bis(oxazoline)-metal complexes for catalytic asymmetric synthesis, and they reserved an important place for Diels-Alder and related transformations. Bis(oxazoline) copper(II)triflate derivatives have been indeed described by Evans et al. as effective catalysts for the asymmetric Diels-Alder reaction [71]. The bis(oxazoline) Ugand 54 allowed the Diels-Alder transformation of two-point binding N-acylimide dienophiles with good yields, good diastereos-electivities (in favor of the endo diastereoisomer) and excellent ee values (up to 99%) [72]. These substrates represent the standard test for new catalysts development. To widen the use of Lewis acidic chiral Cu(ll) complexes, Evans et al. prepared and tested bis(oxazoHnyl)pyridine (PyBOx, structure 55, Scheme 26) as ligand [73]. 

Catalytic activity for the selective oxidation of H2S was tested by a continuous flow reaction in a fixed-bed quartz tube reactor with 0.5 inch inside diameter. Gaseous H2S, O2, H2, CO, CO2 and N2 were used without further purification. Water vapor (H2O) was introduced by passing N2 through a saturator. Reaction test was conducted at a pressure of 101 kPa and in the temperature range of 150 to 300 °C on a 0.6 gram catalyst sample. Gas flow rates were controlled by a mass flow controller (Brooks, 5850 TR) and the gas compositions were analyzed by an on-line gas chromotograph equipped with a chromosil 310 coliunn and a thermal conductivity detector. 

Modified hotocatalysts were prepared using commercial and synthesized Ti02. The modification was carried out in two different methods, i.e. platinization with H2PtCl6 solution and metallization with leached solution from wasted catalytic converter. They were characterized by UV-DRS, BET, and XRD and tested their catalytic performance for decomposition and oxidation of TCE in liquid phase. 

Cobalt-supported-on-MgO catalysts were prepared by impregnating MgO (JRC-MGO-4 lOOOA, 14-16 m g ) with aqueous solutions of Co(N03)2-6H20 (Kanto Co.), followed by drying. The material was then calcined in air for 8 h at 873 K or 1173 K. Before catalytic tests, catalysts were reduced at 1173 K in H2/Ar (50/50 vol.%). 

As illustrated in Fig. 1, the activated carbon displays the highest conversion and selectivity among all the catalysts during the initial reaction period, however, its catalytic activity continues to decrease during the reaction, which is probably caused by coke deposition in the micropores. By contrast, the reaction over the CNF composites treated in air and HN03 can reach a pseudo-steady state after about 200 min. Similiar transient state is also observed on the CNFs and the untreated composite. Table 3 collects the kinetic results after 300 min on stream over catalysts tested for the ODE, in which the activity is referred to the BET surface area. The air-treated composite gives the highest conversion and styrene selectivity at steady state. 

It is found that the CNF-HT has not catalytic activity for ODP. After oxidation, all the three samples show hi ly catalytic performances, which are shown in Fig.3. CNF-HL has the longest induction period among the three samples, and it has relatively low activity and propene selectivity at the beginning of the test. During the induction periods, the carbon balance exceeds 105% and then fall into 100 5%, which implies the CNF structure is stable and the surface chemistry of CNF reaches a dynamic equilibrium eventually. These results indicate that the catalytic activity of ODP can be attributed to the existence of surface oxygen complexes which are produced by oxidation. The highest propene yield(lS.96%) is achieve on CNF-HL at a 52.97% propane conversion. 

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