Industry selected

Light hydrocarbons consisting of oxygen or other heteroatoms are important intermediates in the chemical industry. Selective hydrocarbon oxidation of alkenes progressed dramatically with the discovery of bismuth molybdate mixed-metal-oxide catalysts because of their high selectivity and activity (>90%). These now form the basis of very important commercial multicomponent catalysts (which may contain mixed metal oxides) for the oxidation of propylene to acrolein and ammoxidation with ammonia to acrylonitrile and to propylene oxide. 

Applications Economics favor mechanical-draft towers over hyperbolics, except in very large installations. Considering the climatic and load conditions, natural draft has its best application in the power industry. Selected when (a) operating conditions consist of low wet-bulb temperature and high relative humidity (b) a combination of low wet-bulb and high inlet and exit water temperature exists and (c) heavy winter load is possible. 

Table 2.7 Percentage of total value of shipments accounted for by largest companies in the wet corn milling industry. Selected yearsa...

Adsoiption is a widely used separation process in the chemical process industry. Selectivity is a key property that determines the ease and efficiency of any separation. Although, selectivity is a function of both composition and pressure, most of the design calculations are carried out using a Langmuirian approach with constant selectivity, using only pure component data. The conventional techniques to characterize the selectivity behavior by measuring mixture equilibrium data require a large investment of time and elaborate experimental setup. Moreover selectivity is very sensitive to experimental errors. 

Industrially, selectivity is often as important as conversion in considering the efficiency of the reactor. In isothermal reactions, the dilute phase and transition zone may cause better selectivity due to better contact in that region. But in nonisothermal reactions, the effect will be different because of the temperature effect. Mixing of gas and solids in the dilute phase is not sufficient, and this may cause a temperature distribution for exo- or endothermic reactions. 

If a count were made of all the chemical grout formulations that have passed through patent offices in the past 30 years, it would reach into the hundreds. Although most of those formulations have commercial possibilities, very few have been developed commercially. The majority have been eliminated by the normal industrial selection process. In the United States, from about 1970 onward, two specific materials (silicates and acrylic-based grouts) shared a market percentage estimated at between 85% and 90%, with the remaining portion of the market divided among only six other products. 

Recent trends and developments in industrial selective oxidation technology can be summarized as follows ... 

A relevant issue in industrial selective oxidation is the substitution of air-based to 02-based processes. Air has been the preferred oxidant for years, but several oxidation processes, both in the liquid and in the gas phase, have been modified over the years to allow the use of pure oxygen [241-243, 340]. These changes have been driven by improvements in productivity and yield, while more recently revamping or modifications aimed at pure oxygen use have been undertaken due to environmental constraints. 

Selective hydrogenation of organic compounds is one of the most important reactions in the chemical and pharmaceutical industries. Selectivity in any reaction can be classified as Type 1, II or III according to the nature of reaction involved... 

Table 8. Novel microbial enzymes found in target-oriented screening programs by non-Japanese research groups in academia and industry, selection. (From Refs. [108,112,117-124])...

Marshall PS, Leavens B, Heudi O, Ramirez-Molina C. Liquid chromatography coupled with inductively coupled plasma mass spectrometry in the pharmaceutical industry selected examples. J Chromatogr A 2004 1056 3-12. 

The invention of titanium sificahte, TS-1, resulted in a number of new industrial selective partial oxidation processes including those for the hydroxylation of phenol, the epoxidation of propylene, and the... 

Minor applications of carbon pastes in scientific laboratories and industry (selected examples taken from [4, 5, 85]) (i) conductive substrate in... 

The functionalisation of hydrocarbon feedstocks is a key value-creating step in the chemical industry. Selective oxidation reactions, such as the epoxidation of alkenes, are a substantial basis of fine chemical production [98]. For example, propylene oxide is used industrially in the production of polyurethane and propylene glycol [99], ethylene oxide (EO) is used to produce ethylene glycol and various ethoxylates [100], while cyclohexene oxide is used as an alicyclic chemical intermediate in the production of pesticides, pharmaceuticals, perfumes and dyes [101] or as a monomer in photoreactive polymerisation [102]. 

After a number of candidates were synthesized and partially characterized, the question was which nylon should DuPont begin its venture with The key consideration was the availability of the starting materials. Benzene was considered a prime potential feedstock and since it has six carbon, nylon-6,6, with each reactant (X)ntaining six carbons, was the nylon chosen. This point of ready abundance of inexpensive feedstock has been a critical consideration time and again in industry selecting one compound over another. 

As new greener bulk industrial selective oxidation processes using H2O2 and Ti zeolite-like catalysts have been established (e.g. for producing caprolactam, dihy-droxybenzenes and propene oxide), or are in an advanced development stage (phenol), we can forecast that an increased amount of H2O2 will be needed in the near future. Current worldwide demand for hydrogen peroxide is close to 2 Mt/y and about 0.2 Mt/y would be needed for one propene oxide, or phenol, world-scale plant. 

In a subsequent simulation study, two important industrial selective oxidation processes were addressed in detail, namely the partial oxidation of methanol to formaldehyde and the epoxidation of ethylene to ethylene oxide. In both cases secondary undesired reactions play a significant role, i.e. the combustion of the primary product in the formaldehyde process and the combustion of the ethylene reactant in the ethylene oxide process, so that the study also provided information on how the adoption of high conductivity monolith catalysts would alfect the selectivity of industrial partial oxidation processes for both a consecutive and a parallel reaction scheme. For both processes intrinsic kinetics applicable to industrial catalysts as well as design and operational parameters for commercial reactors were derived from simulation studies and experimental investigations collected in the literature. 

Oxidation processes occupy a prominent place in both the science of catalysis and the catalysis-based modern chemical industry. Selective oxidation, ODH, and ammoxidation represent about 11 % in value of catalysts consumed by the chemical industry and more than 60% in products quantity [1]. Table 13.1 presents the production capacity of the major industrial (amm)oxidation processes [2]. 

Fig. 5.1-10. Scientists in industry, selected fields, 1950-1970. (See Table 5.10, columns...

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