Manufacturing processes selection strategies

The manufacturing process selection strategy is given below, but points 4, 5 and 6 apply to all selection strategies ... 

Quantity - Production quantity per annum, and consequently the number of joints to be produced, accounts for the economic feasibility of the joining process. The quantities specified for selection purposes are the same as for the manufacturing process selection strategy. 

The choice of a development strategy that promises the best answer in the shortest time is the first decision at the start of every process development. This strategy will depend on a number of considerations such as the goal of the development, the know-how of the investigators, the time frame, the available manpower and equipment, and so on. In process development, there is usually a hierarchy of goals (or criteria) to be met. It is simply not possible to reach all the requirements for a technically useful process in one step. The catalyst selectivity (combined of course with an acceptable activity) is the first criterion—-just as in academic research. But when a reasonable selectivity has been obtained, other criteria will become important catalyst activity, productivity and stability, and catalyst separation (and maybe recycling). Then, questions such as the infiuence of substrate quality and last but not least the cost and availability of the chiral catalyst and other materials have to be addressed. The final process is a compromise since quite often not all of these requirements can be fulfilled maximally. It is useful to divide the development of a manufacturing process into different phases (20) ... 

The most important issues for selecting the optimal test strategy are defect levels, where defects are introduced in the manufacturing process, test/inspec-tion effectiveness, and board-dependent issues, such as complexity, production volumes, and electrical and visual access. 

It is now nearly 40 years since the introduction by Monsanto of a rhodium-catalysed process for the production of acetic acid by carbonylation of methanol [1]. The so-called Monsanto process became the dominant method for manufacture of acetic acid and is one of the most successful examples of the commercial application of homogeneous catalysis. The rhodium-catalysed process was preceded by a cobalt-based system developed by BASF [2,3], which suffered from significantly lower selectivity and the necessity for much harsher conditions of temperature and pressure. Although the rhodium-catalysed system has much better activity and selectivity, the search has continued in recent years for new catalysts which improve efficiency even further. The strategies employed have involved either modifications to the rhodium-based system or the replacement of rhodium by another metal, in particular iridium. This chapter will describe some of the important recent advances in both rhodium- and iridium-catalysed methanol carbonylation. Particular emphasis will be placed on the fundamental organometallic chemistry and mechanistic understanding of these processes. 

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