At the Laboratory Scale

we provide examples of various paths of development leading to NIR imaging methods that have been described for the analysis of corn. Although these examples focus on a single commodity, the approaches are universal and provide a good overview of possibilities for the development of NIR chemical imaging 

Factors to Consider in the Development of NIR Chemical Imaging Methods 

Once the objective has been established, the sampling options are appraised. The field of view required for the application, the type of measurement (transmission or diffuse reflection), the type and intensity of the NIR source, requirements for depth of field and spatial resolution must also be established. 

NIR spectroscopy is a staple in the food and agricultural analytical laboratory, and consequently tables of NIR bands arising from the chemical composition of foods are readily available (e.g.. Ref. [3]). These may help to determine if a multispectral or hyperspectral imaging system suits the problem more economically and efficiently. However, it is really the scope of the problem, or question, at hand that ultimately guides the selection of the system. A hyperspectral imaging system is, by definition, a better option in a laboratory setting because it allows 

The final step in the development of a method is to establish the requirements for speed versus the necessary specificity. In short, a method may perform better in terms of specificity if a broad spectral region is used in a comprehensive che-mometric model, but the duration of data acquisition may not be suitable for the application. The opposite is also true, where a single- or dual-wavelength measurement may meet the ideal speed target, but fail in terms of specificity. Various instrumental platforms are available on the market, and it is imperative that a balance between these parameters be achieved for a method to ever reach deployment. For laboratory-based methods, specificity is often much more important than speed, reinforcing the need for a hyperspectral imaging system, if the instrument is to be used for quality control, then speed should be considered in the development of the method. It is important to bear in mind that speed and specificity are not mutually exclusive indeed, they can often both be achieved if the method is properly targeted to the question at hand. 

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The development of the novel Davy-McKee combined mixer—settler (CMS) has been described (121). It consists of a single vessel (Fig. 13d) in which three 2ones coexist under operating conditions. A detailed description of units used for uranium recovery has been reported (122), and the units have also been studied at the laboratory scale (123). AppHcation of the Davy combined mixer electrostatically assisted settler (CMAS) to copper stripping from an organic solvent extraction solution has been reported (124). 

Four column systems are available from Amersham Pharmacia Biotech that can be used to pack SEC media for various applications at the laboratory scale. These include C, XK, SR, and HR column systems. All of the laboratory-scale columns are constructed with borosilicate glass tubes. Columns for larger scale process applications include INdEX, BPG, EineLINE, BPSS, and Stack columns. The larger scale columns are constructed to meet stringent validation requirements for the production of biopharmaceuticals. Each of the column types are described. 

At the laboratory scale, the a-bromoketone was prepared by an Amdt-Eistert reaction which gives the good isomer in a univocal way (eqn. 2). 

Felcht reports that the testing of industrial-scale processes can be performed with low expenditure by using micro reactors, since this should result in a faster time to market of the development [137]. He also sees uses for micro reactors at the laboratory scale as a means of high-throughput screening and model examinations such as fast determination of reaction kinetics. 

Mass indices and environmental factors (equations (5.1) and (5.2)) have been introduced in Section 5.1. For confidentiality reasons, neither chemical names nor exact quantities are specified concerning the industrial case studies. Instead, masses are expressed relatively to input amounts at the laboratory scale. The imit (kg kg ) expresses how many kilograms of substance are needed to produce one kilogram of product. Abbreviations used in captions of the figures are explained in Box 5.2. 

The crystallization step is generally studied quite exhaustively at the laboratory scale and often at the pilot scale. The reaction chemistry should be properly understood to access effects, if any, of the synthesis step on the impurity profile. In batch cooling crystallizers attempts have been made to create optimum conditions by on-line turbidity analysis (Moscosa-Santillan et al., 2000). Physicochemical characterization of the products should be done rigorously (Tanguy and Marchal, 1996). 

Chromium zeolites are recognised to possess, at least at the laboratory scale, notable catalytic properties like in ethylene polymerization, oxidation of hydrocarbons, cracking of cumene, disproportionation of n-heptane, and thermolysis of H20 [ 1 ]. Several factors may have an effect on the catalytic activity of the chromium catalysts, such as the oxidation state, the structure (amorphous or crystalline, mono/di-chromate or polychromates, oxides, etc.) and the interaction of the chromium species with the support which depends essentially on the catalysts preparation method. They are ruled principally by several parameters such as the metal loading, the support characteristics, and the nature of the post-treatment (calcination, reduction, etc.). The nature of metal precursor is a parameter which can affect the predominance of chromium species in zeolite. In the case of solid-state exchange, the exchange process initially takes place at the solid- solid interface between the precursor salt and zeolite grains, and the success of the exchange depends on the type of interactions developed [2]. The aim of this work is to study the effect of the chromium precursor on the physicochemical properties of chromium loaded ZSM-5 catalysts and their catalytic performance in ethylene ammoxidation to acetonitrile. 

Robustness of the process. Many transition metal-catalyzed reactions function well at the laboratory scale, but on scaling up substrate and product inhibition may be an issue, and sensitivity to impurities may also become apparent. Increasing the SCR, which is often necessary for the economics of the process, also increases the impurity catalyst ratio. It is also very important to keep the number of components to a minimum, as extraction, crystallization and distillation are the only economic means of purification. Ligands can be a nuisance in this respect, particularly if they are used in amounts over 5 mol%. Reproducibility also is a stringent requirement. Thus, possible inhibition mechanisms should be recognized in order to avoid unwanted surprises during production. 

While batch reactors remain the workhorse in fine chemical production, the need to switch to continuous processes will increase the use of meso- and micro-structured reactors both at the laboratory scale (for discovery, process data determination, demonstration, small-scale production) and at the production level. 

Several electrolysis regimes may be adopted. At the laboratory scale, exhaustive potential controlled electrolysis is usually preferred. When the electrode potential is poised such that the A concentration at the electrode is zero, the consumption of A and the production of B in the solution (see Section 6.2.8) are represented by the following exponential functions of time, t C° represents initial bulk concentration of the reactant A ... 

A clear advantage of alkaline electrolysers is the use of nickel-based electrodes, thus avoiding the use of precious metals. Catalytic research is aimed at the development of more active anodes and cathodes, primarily the development of high surface area, stable structures. Nickel-cobalt spinel electrodes for oxygen evolution and high surface area nickel and nickel cobalt electrodes for hydrogen evolution have been shown at the laboratory scale to lead to a decrease in electrolyzer cell voltage [47]. More active electrodes can lead to more compact electrolysers with lower overall systems cost. 

This technology has been tested at the laboratory-scale level. 

Particles produced in the gas phase must be trapped in condensed media, such as on solid substrates or in liquids, in order to accumulate, stock, and handle them. The surface of newly formed metallic fine particles is very active and is impossible to keep clean in an ambient condition, including gold. The surface must be stabilized by virtue of appropriate surface stabilizers or passivated with controlled surface chemical reaction or protected by inert materials. Low-temperature technique is also applied to depress surface activity. Many nanoparticles are stabilized in a solid matrix such as an inert gas at cryogenic temperature. At the laboratory scale, there are many reports on physical properties of nanometer-sized metallic particles measured at low temperature. However, we have difficulty in handling particles if they are in a solid matrix or on a solid substrate, especially at cryogenic temperature. On the other hand, a dispersion system in fluids is good for handling, characterization, and advanced treatment of particles if the particles are stabilized. 

Once the analytical method is validated for accuracy at the laboratory scale, it can be used to obtain extensive information on process performance (blend homogeneity, granulation particle size distribution, and moisture content) under various conditions (blender speed, mixing time, drying air temperature, humidity, volume, etc.). Statistical models can then be used to relate the observable variables to other performance attributes (e.g., tablet hardness, content uniformity, and dissolution) in order to determine ranges of measured values that are predictive of acceptable performance. 

For purification, scale-up considerations are important even in the earliest phases of development. It is important to avoid the use of purification techniques of limited scale-up potential even for early clinical production because thorough justification of process changes and demonstration of biochemical comparability are necessary prior to product licensure. For successful scale-up, it is important to understand the critical parameters affecting the performance of each purification step at each scale. Conversely, it is important to verify that the scaled-down process is an accurate representation of the scaled-up process, so that process validation studies, such as viral clearance and column lifetime studies, can be performed at the laboratory scale. 

Conversely, other processes are totally original. This is especially encountered when the electrochemical act is associated with a transition metal complex catalysis. These methods have the advantage of affording the organozinc compound synthesis under simple and mild conditions that are compatible with the presence of reactive functional groups on the substrate. Importantly, these procedures are reproducible and can be run by any chemist. Besides, the preparation from a few millimoles to tens of millimoles of the organometallic compound is easy at the laboratory scale. 

American scientists at LLNL have studied all aspects of scaling-up followed by optimization of parameters and it appears that TATB would be manufactured by them in future by following the TMHI route. However, a new method proposed by the UK scientists is still at the laboratory scale in UK. According to a recent report in the literature, ATK Thiokol, Inc, USA has performed considerable route development for an alternate TATB process starting with phloroglucinol via Scheme 2.1. 

During the past few decades, considerable progress has been made in this area, with catalytic processes having taken the place of stoichiometric reactions. Unfortunately, at present many of these processes are valuable only at the laboratory scale, with few of them appearing to have the potential for industrial exploitation. It is a fact that, since Bazarov s discovery in 1870 [134], the synthesis of urea from ammonia and C02 remains the sole industrially exploited example of C02 fixation into a new C-N bond. 

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