Catalytic reduction apparatus

Other forms of catalytic reduction apparatus which may be used in the laboratory have been described in the following articles.1... 

A solution of 20.8 g. (0.1 mole) of benzalacetophenone (Note 1) (Org. Syn. 2, 1) in 150 cc. of c.p. ethyl acetate (Note 2) is placed in the reaction bottle of the catalytic reduction apparatus (p. 10) and 0.2 g. of platinum oxide catalyst (p. 92) is added. The apparatus is evacuated, then filled with hydrogen, and the mixture shaken with hydrogen until 0.1 mole has been absorbed. The time required is usually about fifteen to twenty-five minutes (Note 3). The platinum is filtered off and the solvent removed from the filtrate by distillation. The benzylacetophenone is recrystallized from about 25 cc. of alcohol and melts at 72-730. The yield is 17-20 g. (81-95 per cent of the theoretical amount). 

The volume of fhe ventiiatior gas by washing for a 6-lane tunnel 1 km in length is approximately 1.5 million m h-, which is almost equivalent to that from middle-size power station plants, while the concentration of NO and other pollutants is much lower. To treat the ventilation air, about 4,000 units of the apparatus in Fig. 8.25 may be necessary. This is considered to be a very large system, but it is estimated that this system is smaller in scale and more cost-effective than those systems using concentrations of NO and NH3, the selective catalytic reduction method. Furthermore, the scale can be smaller if more active air-purifying materials are developed. 

Adams, R. Voorhees, V. Apparatus for Catalytic Reduction Organic Syntheses Volume VIII pgs 10-16... 

Fiq. 41. Cross-sectional view of apparatus used for catalytic reduction to carbon skeleton. Catalyst tube measures 21.7 cm X 0.7 cm o.d. Reproduced from Adhikary and Harkness (A4) with permission. 

Dutton and his colleagues have described the microreactor that they have built which permits reactions to be carried out in an extension of the g.l.c. apparatus to which it is attached. The reactions so performed include bro-mination, silylation, homogeneous and heterogeneous catalytic reduction, and esterification and transesterification by several procedures. ... 

The catalyst is previously prepared in an apparatus for catalytic hydrogenation, in which are placed 0.5 g. of palladous chloride, 3.0 g. of Norite, and 20 ml. of distilled water. The bottle is swept out with hydrogen and then shaken with hydrogen for 2-3 hours at 2-3 atmospheres (40 lb.) pressure. The palladium on carbon is collected on a Biichner funnel, washed with five 50-ml. portions of distilled water, then with five 50-ml. portions of 95% ethanol, and finally twice with ether. Upon drying, about 3 g. of the catalyst is obtained. It is stored in a vacuum desiccator over solid sodium hydroxide. If the reduction of the chloro-lepidine does not proceed normally, the used catalyst should be removed by suction filtration and a fresh 3-g. portion of catalyst added. Failure of the reduction step is usually due to an inactive catalyst or to impurities in the acetic acid or chlorolepidine. The palladium catalysts, prepared as described elsewhere in this volume, are presumably also satisfactory for the reduction of 2-chlorolepidine (p. 77). 

DSC tests show a substantial reduction of the hydrogen desorption onset (red circles) (T J and peak (T ) temperatures due to the catalytic effects of n-Ni as compared to the hydrogen desorption from pure MgH also milled for 15 min. (Fig. 2.57). It is interesting to note that there is no measurable difference between spherical (Fig. 2.57a) and fdamentary (Fig. 2.57b) n-Ni, although there seems to be some effect of SSA. We also conducted desorption tests in a Sieverts apparatus for each SSA and obtained kinetic curves (Fig. 2.58), from which the rate constant, k, in the JMAK equation was calculated. The enhancement of desorption rate by n-Ni is clearly seen. At the temperature of 275°C, which is close to the equilibrium at atmospheric pressure (0.1 MPa), all samples desorb from 4 to 5.5 wt.% within 2,000 s. 

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