Pharmaceuticals, multipurpose reactor

It is important to match mixing equipment capabilities with process requirements. While it is desirable to have an optimum design and operating conditions for every step in the process sequence, it is seldom practical to do so. For example, specialty and pharmaceutical processes require the use of multipurpose reactors. An important consideration is to understand how less-than-ideal equipment wiU function in aU stages of operation. 

Most chiral chemicals are relatively small-scale products (1 to 1000 tonnes per year for pharmaceuticals, 500 to 10000 tonnes per year for agrochemicals) that are usually produced in multipurpose batch equipment This is probably the case for most catalytic reactions described in this chapter however, as a rule very little information on process technology is provided by the manufacturers. Here, we will discuss only briefly the reactor choices for hydrogenation reaction typically carried out in the liquid phase. For a successful implementation the following demands must be met ... 

Pharmaceutical production generally uses multipurpose equipment, and so entrapment behind a membrane would require significant capital expenditure on specialized equipment. In spite of this, the use of membrane reactors in biocatalysis represents an efficient method of enzyme immobilization, given the large molecular weight difference between enzymes (10-150 kDa) and most substrates (300-500 Da). The reader is referred to some recent reviews on the topic. 

The Chemical Development Drug Evaluation branch of Johnson Johnson Pharmaceutical Research Development LLC in Raritan, USA, tested microreactors for processes at elevated temperatures above the limit of most multipurpose conventional reactors, which is above 140°C [34], Operation above this limit is only possible by means of special reactors equipped with heat transfer units. 

Since the early 1990s, the fine chemicals industry has expanded very rapidly. It is estimated that the total capacity of the industry in terms of reactor volume reached 26,000 m in 2002 (Fig. 25.4). This represents 33% of the total global pharmaceutical fine chemical manufacturing capacity of close to 80,000 m, more than 35% of which is not utilized. In the fine chemical industry, a variety of products are being manufactured in multipurpose plants during the course of a year. It is therefore, not possible, to determine the production capacity of a plant in terms of tons per year. Instead, m of reactor volume has been chosen as the reference unit. 

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