Addition of activated carbon

The material was purified by recrystallization from ethanol with the addition of activated carbon. In this manner 24.2 g 1,3-dimethyl-4-[7-[4-(o-methoxyphenyl]-piperizinyl-(1)] pro-pylamino] -uracil having a melting point of 10O C were obtained corresponding to a yield of 75%. The purification may also be effected by boiling the material in acetone to result in similar yields. 

A mixed-valent polymolybdate on active carbon was prepared from molybdenum metal and H202, followed by the addition of active carbon to the aqueous solution [114,115], This catalyzed the epoxidation of several alkenes in 2-propanol using H202 as an oxidant, while the efficiency of H202 utilization was very low (< 25%). The epoxidation likely proceeded mainly on the surface of the catalyst because the recovered catalyst showed almost similar catalytic activity. 

Figure 42. Decline in effluent COD after addition of activated carbon...

Reaction mixtures were prepared by mechanical dispersion of the thiol (200 mg g ) on the activated support. Water (0.5 mL g-1) was added and the mixture was carefully mixed until an homogeneous (hydrated) loose solid was obtained. This solid was left at room temperature or heated in an open vessel for the indicated time. Products were eluted from the support either with diluted hydrochloric acid (cystine, oxidized glutathione, penicylamine) or methanol (tV-acetylcystine, cystine methyl ester). The solution was decolorized by addition of activated carbon, filtered and evaporated. 

A solution of substrate (0.20 mmol), pyrene-dimethyltinhydride (1.2 equiv.), and 2,2 -azobisisobutyronitrile (AIBN, 0.1 equiv.) in dry degassed benzene (1-2 ml) was stirred under reflux for 1 h [thin-layer chromatography (TLC) monitoring] under inert atmosphere. The mixture was cooled to room temperature and evaporated. Methanol/dichloromethane (3 2, 4 ml) was added followed by the addition of activated carbon (800 mg). The suspension was stirred for 30 min [the adsorption of the pyrene core was monitored by ultraviolet (UV)]. After filtration, the activated carbon was washed with methanol and the combined filtrates were concentrated to yield the product in pure form. 

Tris (ethylenediamine) cobalt (III) chloride was first prepared by Werner.1 Resolution was effected through the chloride d-tartrate which was obtained by allowing the chloride (1 mol) to react with silver d-tartrate (1 mol). The correct ratio of chloride ion to tartrate ion is important and this has meant that it was necessary to isolate the pure solid chloride, the synthesis of which has been described by Work.2 In the present method the less soluble diastereo-isomer is isolated directly and the expensive and unstable silver d-tartrate is replaced by barium d-tartrate. The addition of activated carbon ensures rapid oxidation of the initial cobalt (II) complex and eliminates small amounts of by-products of the reaction. 

Addition of active carbons or modified active carbons as a mechanical mixture with the catalyst to the reaction heel can modify, in several cases, the activity and/or the selectivity (fig 1). This experimental fact led us to consider, as developed for aromatic series (fig 2), a reaction scheme taking into account coupling reactions between intermediates and between nitroso and amine, as well as hydroxylamine disproportionation. 

These coupling reactions may play a second role if they yield heavy products that can strongly adsorb on the catalyst surface. Addition of active carbons that enhance production of those species - probably basic carbons [12] - would decrease the metallic surface available for the reduction reactions, and lead to an apparently lower activity. Conversely, addition of carbons that prevent the formation of these heavy products will lead to an apparent higher activity. 

A fascinating application of enhancing mass transfer by physical adsorption on activated carbon recently has been published by Jana-kiraman and Sharma [2l]. These authors studied the role of addition of activated carbon particles with d in alkaline hydro-... 

An addition of activated carbon powder to photocatalytic Ti02 suspension improves water purifying ability (for selected papers, da Silva, 2003 Arana, 2003 Melian, 2003). J.L. Faria insisted that the presence of the activated carbon enhanced the photoefficiency of the Ti02 catalyst for photodegradation of an azo dye in aqueous solution. S.C. Lee et al. have reported air purification by Ti02 immobilized on activated carbon and they... 

Beyond dewatering, however, is the possibility of decontaminating polluted sediments of which there is an abundance of sites and situations. For decontamination the addition of activated carbon, charcoal, or phosphoric rock is possible in which pollutants are adsorbed onto the soil particles and remain in the fabric enclosure while the effluent is decontaminated to the necessary degree. Examples of a number of polynuclear aromatic hydrocarbons and chlorinated chemicals were presented in this regard. 

Table 2 shows the density and IR transmission of pure PS (sample A) and four activated carbon foam samples (samples B-E). With the increase of moisture content, the foam density tends to decrease, which enhances the insulating value. For the IR transmission property, with the addition of activated carbon, its value decreases greatly, which indicates that activated carbon is a good IR absorber. Moisture content shows no effect on the IR transmission property. As described above, IR transmission is a relevant parameter of insidation property. A series of IR transmission measurements of the... 

For the thermal conductivity measurement, sample C and pine PS foam sample were measured by the method described above. It was found that it took 33 minutes for a temperature increase from 33.2 to 34.5°C for pure PS sanple and 40 minutes for sample C. This indicates that with the addition of activated carbon, the thermal conductivity of foam samples decreases. Further experiments by heat flow meter (FOX 200, LaserComp) will be conducted to investigate the effect of activated carbon and moisture. 

In conclusion, with addition of small amount of activated carbon (1 wt.%), the foam products show properties favorable for insulation. Increasing moisture content can facihtate addition of activated carbon in PS and also improve insulation property in some aspect Further experiments need to be conducted to investigate the effect of moisture in activated carbon. 

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