Separator final clearing

Richmond and Phillips (1975) found in the case of Botrytis cinerea that the conidia of the fungi produced distorted germ tubes in the presence of benomyl. In most of the fungi, cell division differed from classical mitosis, the normal states of which were not seen clearly in any of the treated material. Chromosomes became visible at the prophase-metaphase, but they did not completely separate. Finally, the chromatin became stretched into long threads, daughter nuclei did not separate completely and chromatin was often present as irregular shaped masses. 

When the aqueous and Et20 layers were finally clear, they were separated, and 75 g of potassium sodium tartrate was dissolved in the aqueous fraction. NaOH (25%) was then added until the pH was >9, and this was then extracted with 3x75 mL CH2CI2. Evaporation of the solvent under vacuum produced 2.5 g of a nearly colorless clear oil that was dissolved in 300 mL anhydrous Et20 which was saturated with anhydrous HCI gas. The product, 2,3,4-trimethoxyamphetamine hydrochloride (TMA-3) separated as a fine white solid. This was removed by filtration, Et20 washed, and air dried to constant weight. 

Clearly, the time chart shown in Fig. 4.14 indicates that individual items of equipment have a poor utilization i.e., they are in use for only a small fraction of the batch cycle time. To improve the equipment utilization, overlap batches as shown in the time-event chart in Fig. 4.15. Here, more than one batch, at difierent processing stages, resides in the process at any given time. Clearly, it is not possible to recycle directly from the separators to the reactor, since the reactor is fed at a time different from that at which the separation is carried out. A storage tank is needed to hold the recycle material. This material is then used to provide part of the feed for the next batch. The final flowsheet for batch operation is shown in Fig. 4.16. Equipment utilization might be improved further by various methods which are considered in Chap. 8 when economic tradeoffs are discussed. 

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