Selection process filter size

Filtration. Baths should be continuously filtered to remove impurities. Most manufacturers utilize spiral-wound cylindrical polypropylene-type filters with nominal pore-size ratings. Some manufacturers have decreased or actually eUminated the need to dump selected process baths, such as the brown oxide bath, by using a more expensive absolute-type... 

The term virtual library is used quite frequently in the literature these days. Unfortunately there is no common definition on what a virtual library really is. In the simplest case it is a database of fully enumerated structures of products that are under consideration to be made. The generation of such a virtual library involves software that maps the reaction sequence and the corresponding sets of building blocks onto a combinatorial representation (7) (see Note 4). This combinatorial representation can be partially or fully enumerated to generate product structures, which are then stored in structural databases (see Note 5). Subsequently, properties and descriptors to be used in the selection process are to be calculated. As there are limitations in terms of file size etc., such virtual libraries cannot hold more than a few million products. This makes it necessary to filter out reagents (see Subheading 1.3.) prior to construction of the virtual library. 

Results of test work with this filter, producing cakes of 1 mm thickness using a 3 mm clearance, have been pubUshed (33,34). The cake formed on the medium was generally stable, giving high filtration rates over long periods of time, and the precoat type cake did not blind with time. There was no evidence of any size selectivity of the process the only exception was conventional filter aids which were preferentially picked up by the rotating fluid. This... 

In selecting cloths made from synthetic materials, one must account for the fact that staple cloths provide a good retentivity of solid particles due to the short hairs on their surface. However, cake removal is often difficult from these cloths - more than from cloths of polyfilament and, especially, monofilament fibers. The type of fiber weave and pore size determine the degree of retentivity and permeability. The objective of the process, and the properties of particles, suspension and cake should be accounted for. The cloth selected in this maimer should be confirmed or corrected by laboratory tests. Such tests can be performed on a single filter. These tests, however, provide no information on progressive pore plugging and cloth wear. However, they do provide indications of expected filtrate pureness, capacity and final cake wetness. 

BDS process. The pore size of the filter (0.2-1.0 xm) is selected such that the liquid phase, which is miscible with the liquid that is used to wet the filter, passes through the filter, while the second liquid phase remains. Thus, an aqueous filter is wet with a liquid, which is miscible with water, but immiscible with oil. The flow rate is chosen so as to prevent solid deposition through the filter. Although, such a separation process can be applied to any oil/water emulsion, it was particularly envisioned as part of a BDS process. One may ask, whether it would be more efficient to break a macroemulsion by filtering than it is by any other means Second, in the case of microemulsions, how efficient would such a filtration process be ... 

Crystallization remains the primary means of controlling the polymorphic or solva-tomorphic state of a compound, and various groups have examined the influences of processing parameters on the identity and quality of the isolated form. Seeding was used to reduce the size of the metastable zone of eflucimibe, and thereby control the identity of the desired polymorphic identity of the product through a reduction in concomitant crystallization [16], Process improvements have been developed that were found to improve the filterability and enhance the bulk density of ranitidine Form-1 [17], while the variation of process parameters used in an oscillatory baffled crystallizer enabled better selection to be made between the metastable a- and /i-forms of (z.)-glutamic acid [18]. 

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