Batch yield

Until then, the purification of the Fepr protein had been a laborous job as a 240-L batch yielded only as little as 5 mg of protein. With the overexpression clones of the Fepr proteins, the range of proteinconsuming studies such as Mossbauer spectroscopy, EXAFS, and, last but not least, crystallization experiments was greatly extended. Thus, several groups set off to systematically investigate the spectroscopic properties of both Fepr proteins, poised at all four (proposed) redox states. 

The desired reaction is A reacting with H2 to form P, the product. But the product reacts with the reactant A to form an undesirable molecule, BAD. With slower overall heat removal rates in the plant, primarily because the cooling surface area/liquid volume ratio is much larger in the lab, the batch yield in the plant is noticeably less than in the lab. Figures One and Two show in relative terms the quantity of A, P and BAD with time for the two situations. At 97-98% conversion of A, the longer plant reaction time case has four times as much unwanted by-product BAD as the lab case. 

THC. 4.7 g of olivetol (or analog) and 4 g of (+)-menthadienol and 0.8 g of p-toluenesulphonic acid in 250 ml of benzene are refluxed for 5 hours, after any exothermic reaction has begun to subside. Cool, add ether, wash with NaHCOs and dry. Evaporate in vacuo to get a little over 8 g of crude product. Purify by chromatography on 350 g of silica gel in a column 1 inch by 6 feet in petroleum ether. Elute the THC with several portions of benzene. Elute an inactive product with 98% benzene and 2% ether. Elute the unreacted olivetol with 50% benzene and 50% ether and reuse in next batch. Yield of purified product about 4 g. 

The enzyme recLBADH is the first catalyst that has been found to allow the highly regio- and enantioselective synthesis of 5-hydroxy-P-keto esters by reduction of the respective diketo esters. This enzymatic reaction is of enormous preparative value. The substrates are readily available by acylation of P-keto ester bisenolates and the reaction only requires a simple batch technique which is easy to scale up. Reduction of the chlorinated compound la has been performed routinely on a 75 g scale in our laboratory (8 L fed batch), yielding (S)-2a in an isolated yield of 84% [10]. 

Poly(a-phenylethyl isocyanide) was prepared in 55-80% batch yields, using the sulfuric acid droplet dispersion method (20), and a series of fractions with a polydispersity ratio of MJMn of 1.1-1.3 were obtained by precipitation from... 

Batch yield reflects efficiency of the operation. Because yield figures are the sum of numerous interactions, they fail in most cases to provide specific information about process performance and therefore must be used with caution in retrospective validation. In any event, this information should be collected, as it can contribute to further refinement of the yield limits that appear in the batch record. 

Elapsed time to complete steps A, B, and C Batch yield Appearance pH Specific gravity Viscosity Alcohol (% v/v) Assay of active ingredients Dl and D2... 

The time required to accomplish mixing and addition steps is summarized in Table 9. The differences in elapsed time were thought to reflect those typically encountered in manual operations. Batch yield is also shown in the table for future reference. 

Batch number Step Aa Step Bb Step Cc Batch yield (%)... 

The formation of more complex dipeptides was also demonstrated by micro-channel processing through the experiment of converting the amino acid N- -Boc-l-lysine with the additional amino function [5,6]. Although the batch yield is poor with only 9% yield, microreactor synthesis is quantitative in 20 min. 

The dc electrical resistivity p was measured versus temperature for a crystal of KjCfio (Fig. 1). Crystals from different preparation batches yielded similar results. Near room temperature the resistivity is about 5 mO-cm, comparable to that obtained for K3C60 films at room temperature (1. 3). However, because of geometrical uncertainties associated with the contact pads, the absolute value of the resistivity should be considered reliable only to within a factor of 2. Below room temperature, p(T) falls in a metal-like fashion with distinct curvature. At T the resistivity drops abruptly to zero, with a transition width < 200 mK. The inset in Fig. 1 shows p(T) near in detail. The temperature has been swept slowly (—50 mK per minute) near the transition temperature showing no difference in Tj between cooling and warming. 

Metabolic data from the fed-batch development was used to develop a supplemented batch process involving the addition of up to three of the feeds added in the fed-batch process, to the culture medium prior to inoculation of the cells. Final antibody yields are not as high as for the fed-batch process, typically an increase of 2-fold over batch yields compared to 3- to 4-fold increases for the fed-batch. However, the process offers a relatively simple way of obtaining increased antibody yields. Fig. 3.16 shows a supplemented batch culture for clone C where the final antibody concentration reached 1.3 g L . ... 

Five batches of the vinyl ether reaction were monitored by mid-lR using ReactlR MP (Mettler Toledo) during a pilot-plant campaign. Each batch yielded approximately 215 kg of vinyl ether for downstream production of aprepitant (Emend ) for phase 11 and 111 clinical trials. 

Still is charged with 1,200 liters/ batch (1,560 kg) total evaporation 1,200 liters/hr. Offtake is, say, 100 liters/hr for 2 hr and then 200-300 liters/hr originally temp in kettle is 25-30°C and rises to 60°C at end. Batch takes 8-12 hr to complete yield 1,090 kg F12 per batch. First fraction is F13 with small quantities of FI2 and is put back to still with next batch. Quantity about 130-260 kg per batch. Residues from still at end of distillation are returned to autoclave or distilled at ordinary pressure to give FI 1 for sale quantity 120-130 kg/batch. Yield of F12 90% on carbon tetrachloride, 80% on hydrogen fluoride. 

The batch yield of via the Te(p,n) process generally amounts to about 500 MBq in exceptional cases, yields of about 2 GBq have been reported. These yields are sufficient for local medical use, but not for wide distribution. The increasing demands for this radionuclide call for more development efforts and the production route is now being commercialized. 

The calculated integral yields for the latter two processes are given in Fig. 39.10a. The targetry with enriched Zn or Zn is similar to that for production of Ga from Zn, and so it is well established. The chemical separation of radiocopper is based on a combination of solvent extraction and ion-exchange processes. So far the achievable batch yields of Gu, mostly via the Zn(p,2p) process, have been limited to about 1 GBq. 

Molar concentration of Na2S04 or BaCl2/Molar solubility of BaS04, the cone produced crystals at 6000rpm that had a Sauter mean diameter of 3.2 microns, compared to 6.85 microns from the batch runs. However, at a supersaturation of 5000, the batch yielded a Sauter mean diameter of 0.75 microns, compared with 0.18-0.32 microns from the disc of the cone. The particle size distributions reproduced in Figure 6.15 highlight the cone behaviour at 8000rpm more starkly, with a decided shift to 0.1 1 microns, compared with 1-10 microns in the batch. 

An additional selection criterion is a detectable metastable zone width. Every solution has a maximum amount that it can be supersaturated before becoming unstable. The zone between the solubility curve and the unstable boundary is referred to as the metastable zone. In an initial seeded batch the supersaturation is always maintained within the metastable zone to minimise nucleation, the formation of new unwanted tiny crystals known as fines. These either cause filtration problems or reduce batch yields by blocking or passing through screens. 

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