Scientific design process

The UCB collection and refining technology (owned by BP Chemicals (122,153—155)) also depends on partial condensation of maleic anhydride and scmbbing with water to recover the maleic anhydride present in the reaction off-gas. The UCB process departs significantly from the Scientific Design process when the maleic acid is dehydrated to maleic anhydride. In the UCB process the water in the maleic acid solution is evaporated to concentrate the acid solution. The concentrated acid solution and condensed cmde maleic anhydride is converted to maleic anhydride by a thermal process in a specially designed reactor. The resulting cmde maleic anhydride is then purified by distillation. 

Ethylene oxide (qv) was once produced by the chlorohydrin process, but this process was slowly abandoned starting in 1937 when Union Carbide Corp. developed and commercialized the silver-catalyzed air oxidation of ethylene process patented in 1931 (67). Union Carbide Corp. is stiU. the world s largest ethylene oxide producer, but most other manufacturers Hcense either the Shell or Scientific Design process. Shell has the dominant patent position in ethylene oxide catalysts, which is the result of the development of highly effective methods of silver deposition on alumina (29), and the discovery of the importance of estabUshing precise parts per million levels of the higher alkaU metal elements on the catalyst surface (68). The most recent patents describe the addition of trace amounts of rhenium and various Group (VI) elements (69). 

Activated alumina and phosphoric acid on a suitable support have become the choices for an iadustrial process. Ziac oxide with alumina has also been claimed to be a good catalyst. The actual mechanism of dehydration is not known. In iadustrial production, the ethylene yield is 94 to 99% of the theoretical value depending on the processiag scheme. Traces of aldehyde, acids, higher hydrocarbons, and carbon oxides, as well as water, have to be removed. Fixed-bed processes developed at the beginning of this century have been commercialized in many countries, and small-scale industries are still in operation in Brazil and India. New fluid-bed processes have been developed to reduce the plant investment and operating costs (102,103). Commercially available processes include the Lummus processes (fixed and fluidized-bed processes), Halcon/Scientific Design process, NIKK/JGC process, and the Petrobras process. In all these processes, typical ethylene yield is between 94 and 99%. 

Aniline can also be produced when phenol is subjected to gas-phase ammonolysis at 200 bar and 425°C in an adiabatic, fixed-bed reactor. This is the Halcon/Scientific Design process. The chemistry is ... 

This is the Halcon/Scientific Design process. The chemistry is ... 

In the presence of triethylalununum, the Goodyear-Scientific Design process produces 2-methvl l-oentene with a selectivity of 99 molar per cent The reaction takes place around 200 at 20.10 Pa. 2-metbyl 1-pentcnc is the starting material for the synthesis of isoprene, in which it is hrst isomerized to 2-methyl 2-pentenes, and then cracked to produce isoprene. 

Fig. 12.4, Adipic acid production by two-stage oxidation orcyclohexane With air (boric acid) and nitric acid. Scientific Design process.

In the Scientific Design process (13,14), air, ethylene, and recycled gases are passed over a fixed-bed, supported silver catalyst at 230-350° and 150-300 psig. The catalyst is in tubes cooled externally by an organic cooling medium. A smaller, secondary, once-through reactor is used to convert much of the unreacted ethylene in the pui e gases. 

The effluent stream contains a low concentration of MA in the gas phase (1.5% by weight). Part of this is recovered as a solid by cooling the effluent as in the Ruhroll process. The Scientific Design (SD) process, on the other hand, collects MA as a molten liquid by cooling the stream above the dew point of water. This prevents formation of any significant concentration of maleic acid produced by hydrolysis which may potentially isomerize to fumaric acid. (See Chapter 1.) The molten MA is collected as such in the Scientific Design process.Alternatively, the molten MA can be collected on ceramic supports as claimed by Monsanto. 

Process Technology Evolution. Maleic anhydride was first commercially produced in the early 1930s by the vapor-phase oxidation of benzene [71-43-2]. The use of benzene as a feedstock for the production of maleic anhydride was dominant in the world market well into the 1980s. Several processes have been used for the production of maleic anhydride from benzene with the most common one from Scientific Design. Small amounts of maleic acid are produced as a by-product in production of phthaHc anhydride [85-44-9]. This can be converted to either maleic anhydride or fumaric acid. Benzene, although easily oxidized to maleic anhydride with high selectivity, is an inherently inefficient feedstock since two excess carbon atoms are present in the raw material. Various compounds have been evaluated as raw material substitutes for benzene in production of maleic anhydride. Fixed- and fluid-bed processes for production of maleic anhydride from the butenes present in mixed streams have been practiced commercially. None of these... 

Tailoring of the particle size of the crystals from industrial crystallizers is of significant importance for both product quality and downstream processing performance. The scientific design and operation of industrial crystallizers depends on a combination of thermodynamics - which determines whether crystals will form, particle formation kinetics - which determines how fast particle size distributions develop, and residence time distribution, which determines the capacity of the equipment used. Each of these aspects has been presented in Chapters 2, 3, 5 and 6. This chapter will show how they can be combined for application to the design and performance prediction of both batch and continuous crystallization. 

Figure 7-3. The Scientific Design Co. Ethylene Oxide process (1) reactor, (2) scrubber, (3,4) C02 removal, (5) stripper, (6,7) fractionators.

Figure 7-4. The Scientific Design Co. process for producing ethylene glycols from ethylene oxide (1) feed tank, (2) reactor, (3,4,5) multiple stage evaporators, 4 operates at lower pressure than 3, while 5 operates under vacuum, evaporated water is recycled to feed tank, (6) light ends stripper, (7,8) vacuum distillation columns.

Ammonolysis of phenol occurs in the vapor phase. In the Scientific Design Co. process (Figure 10-10), a mixed feed of ammonia and phenol is heated and passed over a heterogeneous catalyst in a fixed-bed sys-... 

Each of these goals requires the synthesis of a compound with sufficiently selective binding and concomitant fluorescent signal transduction in water. However, the scientific base on which to start the rational design process does not, at present, exist. We have set as our research agenda the evaluation of new ways in which an ion or molecule recognition event can be transduced into a fluorescence event. 

Ethylene oxide was formerly made in a two-stage process by first adding HOCl to ethylene and then removing HCl. However, in the 1960s Scientific Design, Union Carbide, and Shell Oil developed a one-step direct oxidation process that has largely replaced the old chlorohydrin process. 

A clinical trial is an experiment and not only do we have to ensure that the clinical elements fit with the objectives of the trial, we also have to design the trial in a tight scientific way to make sure that it is capable of providing valid answers to the key questions in an unbiased, precise and structured way. This is where the statistics comes in and statistical thinking is a vital element of the design process for every clinical trial. 

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