Catalysts conversion

Ring enlargement of benzene derivatives by carbenes generated from diazo compounds (better in the presence of a Rh catalyst) Conversion of aldehydes to ketones by diazo compounds (Schlotterbeck) see also Ptau Planer... 

Fig, 8. Principle of operation. Three-way redox catalyst conversion characteristics. 

Figure 1. CH reactions with different oxidizing compounds over CoZSM-5 catalyst conversion of NO into (A) and of CH into COj (B) as a function of temperature. Catalyst weight was 100 mg, feed contained 0.28% CH4, 0.21% NO or NOj (when used), and 2.6% Oj (when used) in He at a flow rate of 75 ml/min (GHSV = 22,500 h- ).

GP 4] [R 11] For methanol conversion over sputtered silver catalyst, conversion increases almost linearly from 430 to 530 °C (8.6 vol.-% methanol balance oxygen ... 

GP 4] [R 11] For methanol oxidation over sputtered silver catalyst, conversion is higher when using micro channels of smaller diameter (8.5 vol.-% methanol balance oxygen 510 °C 4—27 ms sHghfly > 1 atm) [72]. For two channels of the same width, but different depths (70 pm, 130 pm), concentration differences of nearly 10% at the same residence time were detected, all other parameters being equal. 

Run Nitrile Hydrosilane Catalyst Conversion (%) Yield of produce (%)... 

Catalyst Activity Measurements. Activity measurements for thiophene HDS and the consecutive hydrogenation of butene were carried out in a Pyrex-glass, fixed-bed reactor at 625 K and at atmospheric pressure as described in Ref. (9). Before the measurements the catalysts were presulfided in 2% H2S in H2 at 675 K. For each catalyst conversions were measured at different space velocities of the thiophene/H2 mixture (2.5 thiophene) and the catalytic activities are here expressed as pseudo first-order rate constants as-... 

Iron(II) sulphate is a by-product in many industrial processes, such as the manufacture of titanium dioxide, the pickling of steel sheet before galvanising and the reduction of aromatic nitro compounds to amines using iron catalysts. Conversion of waste iron (II) salts to usable iron oxide pigments, where the quality requirements are not too stringent, is therefore a useful proposition, since it uses up chemicals that would otherwise be regarded as waste products. 

For the complete vapor-phase oxidation of methane over a palladium alumina catalyst, conversion-space-time data were taken at 350°C and 1 atm total pressure the fractional factorial design of Table X (Hll) specified the settings of the feed partial pressures of the reacting species. 

An example of the data, broken down into the 13 product groups, calculated tom the distillation and GC analysis of the hydrocracked liquids from CoMo-catalysed experiments is shown in Table II. It can be seen that the distribution of each of the contacts is similar, reflecting no dependence on repeat contact, even in the case of the first contaa which used tosh catalyst. This situation was generally observed for the other catalysts used and a summary of the r ts for the four catalysts is shown in Table III. The results for ZnW could be interpreted as a gradual decrease in conversion to material bpt <260 C or <275°C. However, this interpretation would depend highly on the reliability of the result for the fifth contact, the two runs of which were carried out on the same autoclave rather than one on each autoclave. The discussion further in the text does indicate that, at shorter contact times, conversions can be dependent upon the autoclave used, and the low value for this fifth contact probably results tom this dependence rather than a dependence on contact Hence it was concluded that, for all the catalysts, conversions to the various bpt materials were independent of repeat contact. 

Figure 6.20 Hydrogenation of 3,4-dimethoxyacetophenone (353 K, 1 MPa H2, 0.25g catalyst). Conversion as a function of time for Pt/Si02 ( ) and PtSn-OM (A) catalysts. (Reproduced from Reference [46].)...

Table 3. Reaction of C3H0 at 773 K, 760 torr over ZSM-5 based catalysts. Conversion range 1-3%...

Catalyst conversion (mol.%) a-pinene oxide 1,2 pinane diol conversion efficiency... 

Catalysts Conversion (%) Selectivity (%) 4-tert- Flavan butylphenol Yield (%) of Flavan... 

The reaction was carried out using Nafion-H and polystyrene sul-phonic acid resin catalyst at 180°C and 140°C, respectively, which are their maximum temperatures of use 2-nitrotoluene solvent and 10% w/w catalyst. Conversions of 20% and 1.5% were obtained at the end of six hours indicating that higher temperatures will be necessary to achieve appreciable rates on these catalysts. Since these catalysts are not structurally stable above the respective temperatures, they appear to be unsuitable for this application. The reaction was also carried out using triflic acid as catalyst at various temperatures. The results are shown in Fig.3. Surprisingly, the reaction did not proceed beyond 40% conversion in spite of the high acidity of the catalyst. 

Figure 21.3 The relationship between n-hexane conversion and isomerization selectivity in n-hexane-H2 reactions at 623 K. (a) WC and (b) Mo2C catalysts. Conversions were varied by changing flow rates of 6% n-hexane-H2 mixture. Top panel , WC/fresh , WC/RT . WC/200 O, WC/400 Botton panel , Mo2C/RT , Mo2C/fresh.

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