Purity improving

The higher yields represent improvements in alkylation efficiency and better utilization of the benzene feedstock. The higher purities improve the efficiencies of downstream technologies, so that ultimately less energy is consumed in the styrenic and phenolic chains for producing plastic products. Another important factor is that the zeolitic catalysts are more environmentally friendly materials than aluminum chloride and SPA. 

Figure 10.3c shows how the disturbance affects benzene product quality. The maximum deviation in the control tray temperature is about 2°F. Notice that- a constant tray temperature does not give constant benzene purity, which changes by 0.015 mole %. Reflux flowrate is constant in the product column, so product purity improves as the feed rate to the column decreases. 

Substantial savings can be realized by root purity improvement from agronomic means such as variety improvement or from an effective chemical application. Harvest impurities consist primarily of amino nitrogen, betaine, and potassium, sodium, and chlorine. 

Reduction of Crystallization by Purity Improvement One root cause for crystallization even with a reduced oxygen content can be attributed to further impurities at the particle surface. The trivial fix for this would be an improvement in purity, which is actually difficult to achieve with the conventional K2-salt Na-reduction process described above (see p. 63). However, the second route, that is the Ta metal powder production by Mg reduction of the oxides, delivers purer metal powder grades (at least with respect to alkali elements). Therefore, this route may be superior for ultra-high CV powders. Moreover, higher purity is beneficial to achieve a higher BDV (break down voltage) as is known from E-beam melted powder. 

The transformation of the anhydrous sodium warfarin, an amorphous substance, into the solvate, which is crystalline, demonstrates the utilization of technology for some commercial advantages. The amorphous sodium warfarin is crystallized from isopropanol to form a clathrate with a molecular ratio of 2 1. This formation was awarded a patent extension because of the material crystallized out of the solution, resulting in purity improvement. " ... 

Multivariate curve resolution can be used for the analysis of augmented sets as a way of reinforcing conclusions on peak purity, improving the resolution of overlapping compounds, and performing multicomponent determinations in the presence of interferences. 

In one of the examples, it is described that supercritical CO2 at conditions of 53 atm and 40 °C in a static reactor increased the purity of vanillin from 82% to 93 % in a single stage. Compounds such as guaiacol, light ends and tar, and acetovanillone were dissolved by the CO2 preferentially. For additional experimental results, the patentee related that all the tests described in the examples were repeated with liquid CO2 at 25 °C (no pressure was stated) and that no purity improvement was seen. At the end of the invention. section the patentee states that he considers the term supercritical in his claims to consist of a temperature higher than the criucal temperature but not necessarily a pressure higher than the critical pressure. 

The above behaviour is unusual, in contrast with zeotropic systems, where the purity improves always by increasing the reflux. The explanation may be found in a dilution effect by solvent at higher reflux, making that its effect on the relative volatility of components drops too. 

In the purification of oleic acid from a mixture containing 5% linoleic acia, the purity improved only to 96.2% in a -form, while it improved to 99.1% in / -form (11),... 

Zeng and co-workers assembled an automated prepLCMS system using MS-triggering technique to collect fractions. Among the 12 samples tested, the average purity improved from about 30% to over 90%. Two switching valves allowed the system to select either analytical or preparative applications. Based on a similar principle, several commercial MS-triggered systems are now available. 

Wafer cassette - ESD PEEK Gudeng Precision Industrial ESD, low particle generation, outgassing, purity, improved wafer yield... 

Remarkably, according to these pieces of information, Fischer had correctly interpreted his observations. An interesting fact in this context is that Amadori referred to the studies by Schiff, Sachsse, Irvine as well as those of Claus and Ree, but did not consider Fischer s important contribution. Amadori also had reported yields of around 70% of thep-phenetidino product but researchers following his work failed to reproduce these results. Improvements were made by Wey-gand [20], who was the first to recognize that both yields and product purity improved considerably when the reaction was performed under acidic conditions a very important discovery in connection with this reaction. 

Brown, H. C. Desai, M. C. Jadhav, P. K. 1982. Hydroboration. 61. Diisopinocampheylborane of high optical purity, improved preparation and asymmetric hydroboration of representative cis-disubstituted... 

---