Secondary considerations

Arylamines are generally prepared by the reduction of nitro compounds. When only small quantities are to be reduced and the time element is important and cost is a secondary consideration, tin and hydrochloric acid may be employed, for example ... 

Kneading Devices These are closely related to the agitated pan but differ as being primarily mixing devices with heat transfer a secondary consideration. Heat transfer is provided by jacketed construction of the main body and is effected by a coolant, hot water, or steam. These devices are applicable for the compounding of divided solids by mechanical rather than chemical action. Apphcation is largely in the pharmaceutical and food-processing industries. For a more complete description, illustrations, performance, and power requirements, refer to Sec. 19. 

Pneumatic-Conveying Devices See Sec. 21 for descriptions, ratings, and design factors on these devices. Use is primarily for transport purposes, and heat transfer is a very secondary consideration. 

As a secondary consideration, the chromatographer may also need to know the minimum value of the separation ratio (a) for a solute pair that can be resolved by a particular column. The minimum value of (a) has also been suggested [8] as an alternative parameter that can be used to compare the performance of different columns. There is, however, a disadvantage to this type of criteria, due to the fact that the value of (a) becomes less as the resolving power of the column becomes greater. Nevertheless, a knowledge of the minimum value of (cxa/b) can be important in practice, and it is of interest to determine how the minimum value of (aA/B) is related to the effective plate number. 

After completing our analysis of the effects of the dominant equilibrium, we may need to consider the effects of other equilibria. The calculation of [H3 O ] in a solution of weak base illustrates circumstances where this secondary consideration is necessary. Here, the dominant equilibrium does not include the species, H3 O, whose concentration we wish to know. In such cases, we must turn to an equilibrium expression that has the species of interest as a product. The reactants should be species that are involved in the dominant equilibrium, because the concentrations of these species are determined by the dominant equilibrium. We can use these concentrations as the initial concentrations for our calculations based on secondary equilibria. Look again at Example for another application of this idea. In that example, the dominant equilibrium is the reaction between hypochlorite anions and water molecules H2 0 l) + OCr(c2 q) HOCl((2 q) + OH ((2 q) Working with this equilibrium, we can determine the concentrations of OCl, HOCl, and OH. To find the concentration of hydronium ions, however, we must invoke a second equilibrium, the water equilibrium 2 H2 0(/) H3 O (a q) + OH (a q)... 

A basic, or prima facie, case of obviousness, which would otherwise defeat patentability, may in turn be defeated by one or more "secondary considerations [18]." One of the most commonly employed secondary considerations is a "superior and unexpected result [18]." At trial, Apotex... 

Concerning the bisulfate salt, Sanofi presented evidence that "the prior art taught away from the use of sulfuric acid with the claimed enantiomer, for strong acids could encourage re-racemization [23]." "Teaching away" from, a separate secondary consideration trending toward patentability, is discussed in more detail in Section 7 of this chapter. 

Suggested Best Practices for Chemists "Teaching away" from, like a "superior and unexpected result," is another secondary consideration that can be used to defeat a primafacie case of obviousness [37]. 

Temperature. In most cases, the solubility of the material which is being extracted will increase with temperature to give a higher rate of extraction. Further, the diffusion coefficient will be expected to increase with rise in temperature and this will also improve the rate of extraction. In some cases, the upper limit of temperature is determined by secondary considerations, such as, for example, the necessity to avoid enzyme action during the extraction of sugar. 

Practical concerns, specifically mass transfer, Umit the recovery to values in the high 70% range. All this said, the vast majority of operating air separation units are the small capacity medical oxygen concentrators. These operate under either PSA or VSA or trans-atmospheric process cycles. The key objective for medical O2 is small unit size and power consumption prior to the push for portability was a secondary consideration. There are many such PSA air separation units that operate at recoveries as low as 35%. 

Smoke is composed of combustion gases, soot (solid carbon particles), and unburnt fuel. For outdoor fires, the impact of smoke is usually a secondary consideration after the heat transfer. In many circumstances, the immediate thermal threat from the fire plume (jet, pool, or flash fire) overwhelms the smoke threat, particularly for personnel in close proximity to the event. There may be circumstances where personnel are in a downwind smoke plume where there is no immediate thermal threat. As a rule-of-thumb, all people within a smoke plume may be immediately or nearly immediately affected and at risk from a life safety standpoint (be it from lack of visibility or by toxic products). 

A more detailed evaluation of the diverse structures proposed for the secondary species goes beyond the scope of this review. We mwely emphasize that the ESR results provide detailed evidence for the nature of the radical center, but fail to elucidate the cationic site. The identity of this center is left to secondary considerations or speculation. We also note that any alternative structure has the virtue of not contradicting the ab irutio calculations the potential c ture of chloride ion has precedent in the nucleophilic substitution at a cyclopropane carbon (see Section 7). Another type of ring-opened structure has been postulated as an intermediate in the aminium radical cation catalyzed rearrangement of l-aryl-2-vinylcyclopropanes (see Section 5). 

Modification of the metal itself, by alloying for corrosion resistance, or substitution of a more corrosion-resistant metal, is often worth the increased capital cost. Titanium has excellent corrosion resistance, even when not alloyed, because of its tough natural oxide film, but it is presently rather expensive for routine use (e.g., in chemical process equipment), unless the increased capital cost is a secondary consideration. Iron is almost twice as dense as titanium, which may influence the choice of metal on structural grounds, but it can be alloyed with 11% or more chromium for corrosion resistance (stainless steels, Section 16.8) or, for resistance to acid attack, with an element such as silicon or molybdenum that will give a film of an acidic oxide (SiC>2 and M0O3, the anhydrides of silicic and molybdic acids) on the metal surface. Silicon, however, tends to make steel brittle. Nevertheless, the proprietary alloys Duriron (14.5% Si, 0.95% C) and Durichlor (14.5% Si, 3% Mo) are very serviceable for chemical engineering operations involving acids. Molybdenum also confers special acid and chloride resistant properties on type 316 stainless steel. Metals that rely on oxide films for corrosion resistance should, of course, be used only in Eh conditions under which passivity can be maintained. 

The driving force behind the commercial acceptance of sulphur extended asphalts is the cost reduction potential. Improved pavement performance, while of importance, is a secondary consideration. AC prices have been soaring recently in tandem with crude oil prices and continued rapid price escalation is forecast together with geographic shortages of asphalt. In many parts of North America a partial substitution of asphalt by sulphur will result in a reduction in cost per tonne of hot mix, and of course the use of sulphur will offset asphalt shortages (of up to 27%), wherever these shortages may occur. 

While shipboard supplies of water are vital to navies and the maritime industry, the saline water conversion program of the Department of the Interior is interested in a different phase of the over-all problem. Aboard ship the primary interest is a reliable supply of water the cost of the water is of secondary consideration. The interest of the Office of Saline Water is centered on land-based plants that can produce fresh water from the sea at low cost, the latter being the important factor. 

Issues related to prior art enablement, prima facie obviousness and secondary considerations of nonobviousness often intertwine in obvious determinations during patent prosecution and litigation since their definitional boundaries are often not well demarcated. In the case Sterling Drug Inc. v. Watson,69 the USPTO rejected claims to various single enantiomer compounds,70 and this decision was appealed to the U.S. District Court for the District of Colombia. The claims in question—10,12, and 14—are presented in Figure 8.18 together with the claimed structures (L-arterenol is the neurotransmitter norepinephrine).71... 

While we have focused extensively on unexpected results as one of the secondary considerations of nonobviousness, there are several additional considerations that can be argued. In this opinion, the Court addressed these several additional secondary considerations of nonobviousness as well. These additional important factors include commercial success, simultaneous invention, fulfillment of long-felt need, prior failure, others copying of the invention, third-party praise and recognition, and skepticism of persons skilled in the art. 

The next secondary consideration that the Court took up was near simultaneous invention. If two or more separate inventors almost simultaneously discover an invention, this can be regarded as secondary evidence that the invention is obvious. Mylan presented evidence that multiple other groups had synthesized levofloxacin within one year after the inventors of the challenged patent. The Court only assigned moderate emphasis to this secondary evidence, however, because Mylan provided no corroborating evidence as to the exact date of four out of five of the near simultaneous discoveries. This was an issue because one of the inventors of the patents in suit published on some of levofloxacin s properties and general resolution methods soon after they made their discovery of levofloxacin. Thus it was not clear whether the near-simultaneous invention from the other four groups was due to the obviousness of the invention at that time or because of the inventor s own disclosure.85... 

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