Solvent differential batch

In another example of differential heating, a two-phase water/chloroform system (1 1 by volume) was heated in a microwave batch reactor (MBR)65. About 40 s after commencement, the temperatures of the aqueous and organic phases were 105 and 48°C, respectively, because of the differences in the dielectric properties of each solvent. A sizeable differential could be maintained for several minutes before cooling was begun. Differential heating is particularly advantageous for Hofmann eliminations. In a typical example,... 

Thermogravimetric analysis (heating rate 10°C/min) of PPNA revealed that the polymer was stable to at least 220°C in an N2 atmosphere. (Figure 2) Differential scanning calorimetric measurements (heating rate 10°C/min) on several batches of PPNA indicated that Tg varied between 125-140°C. This variation may be a reflection of the amount of solvent (NMP) entrapped in the... 

If a deep bed u used in a reflux extractor the exlractur can be analyzed tike fixed-bed extractors operating with dtiwnftow and yj0 0. In such a case V = Ee. However, if the bed is Hooded and consequently part of the reflux bypasses the bed. V should be based on an Eh that barely results in bed saturation rather than the actual Efe. If the refluxed solvent b not passed throngh a bed but is edded 10 a well-mixed batch of extract and solid and the rate of extract discharge is E . the extractor can be treated like a diflcrtmriel extractor. Reflux extractors in which very short beds are used can also be treated like differential extractors as a mesonablc approximation. 

Differential extraction. This is a batch operation wherein a definite amount of solution to be extracted is contacted with differential portions of extracting solvent, the differential portions of extract being removed as fast as formed. The operation is exactly analogous to differential distillation and has been termed cocurrent infinite stageby Varteressian and Fenske (22). 

Cocurrent multiple contact. This may be batch or continuous and is an extension of the single contact wherein the raffinate is contacted repeatedly with fresh extracting solvent. In the limit represented by an infinite number of stages, this becomes the same as differential extraction. 

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