Kieselguhr, efficiency

Filter Aids are porous powders added in small quantities to a soln or suspension to be filtered, in order to increase the efficiency of filtration. They are useful when handling suspensions of finely divided solids or of colloidal materials. The aid should not be much. heavier than die liquids to be filtered, so that it will not settle immediately but will remain in suspension for a while. Kieselguhr and paper pulp are the most widely used filter aids. Others are sawdust, charcoal, Fuller s earth, magnesia, salt, gypsum and some activated charcoals. The charcoals act as decolorizers at the same time... 

Other supports Of other support materials, perhaps polytetrafluoroethyelne (PTFE) is the most important because, although so far the column packings made from it are not as efficient as those made from kieselguhr, its adsorptive capacity is lower than that of any other suitable material. Consequently, symmetrical peaks can be obtained on PTFE-based columns for water, alcohols and amines. The chemical inertness of PTFE is of value for separation of halogens and interhalogen compounds. 

Activated carbon finds many applications as a carrier for other catalysts. Apart from providing a large surface, various other benefits have been observed to attend the use of activated carbon as a carrier for other catalysts. One value is that the catalyst can be prepared at low temperatures—a feature generally desirable. Thus nickel salts deposited on activated carbon can be formed into an efficient catalyst at 350° to 400° C whereas temperatures of 420° to 450° C are required when kieselguhr is used as a support, and 550° C or higher with silica gel.6... 

Trambouze (39) et al. carried out investigations on the activity of nickel catalysts. Teichner and Pernoux (40) found that the efficiency of kieselguhr important for Fischer precipitation catalysts is proportional to the quantity of reactive silica. Examinations with electron microscope... 

Once near steady-state activity had been reached (19 hours), the temperature was decreased 15 °F, and the effect of decreased temperature on conversion and selectivity established, Run 4. An estimated activation energy for the conversion of methylcyclohexane is 28 kcal/mole, only 2 kcal less than the approximate value for the nickel-kieselguhr catalyst. The effect of decreased operating pressure is shown by the data of Run 5. Conversion increased, and efficiency to cyclohexane decreased slightly. The same effect was noted previously in fixed bed tests with Preparation A. 

B. Drying agents depending upon physical action (adsorption) for their efficiency Alumina (low temperature fired), asbestos, charcoal, clay and porcelain (low temperature fired), glass wool, kieselguhr, silica gel, refrigeration. 

Dynamite, efficiency of, 118. frozen dynamite, 116. gelatine dynamite, 119. properties of kieselguhr dynamite, 116. Reid Borland s carbo-dynamite, 119. Rhenish dynamite, 119. various kinds of 119. 

For evaluation of catalytic efficiency, the specific reaction employed was the hydrogenation of a-octene-1 in ethanol solution. The reference material chosen was Harshaw 0104 P (a nickel catalyst on kieselguhr manufactured for olefin hydrogenations). For both catalysts, the conversion of octene-1 to octane was measured by gas-liquid chromatography (GLC). The results of the catalytic activity measurements indicated that the PEO-protected nickel catalyst is comparable to the commercial Harshaw product. In addition, it could have several advantages, including convenience and greatly increased shelf life. 

For many years after the fat hydrogenation process was introduced, manufacturers made their own catalysts when they were needed. Then, gradually, the nickel salt producers began to make the catalysts for operators. This improved quality and ensured more efficient operation. By 1928 the best catalyst supports were found to be kieselguhr or fuller s earth,charcoal, " and complex silicates such as permutite. Many other practical ideas were introduced such as ... 

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