Techniques separation processes, early work

The second important piece in the process development is the separation scheme. Several methods were suggested, such as decanting, water extraction or fractional distillation, use of hydrocyclones, hydrophobic membrane filters, etc. In the early work at EBC, many of its patents refer to facilitating catalyst separation via immobilization, although no mention is given on how activity was impacted by that immobilization. Furthermore, there were no details on how immobilization was achieved and which were the preferred means and techniques. 

Since the discovery of the Loeb-Sourirajan technique in the 1960s, development of the technology has proceeded on two fronts. Industrial users of the technology have generally taken an empirical approach, making improvements in the technique based on trial and error experience. Concurrently, theories of membrane formation based on fundamental studies of the precipitation process have been developed. These theories originated with the early industrial developers of membranes at Amicon [19,22,24] and were then taken up at a number of academic centers. Unfortunately, much of the recent academic work is so complex that many industrial producers of phase separation membranes no longer follow this literature. 

Partition chromatography originated with the work of Archer John Porter Martin (6. 1910) in the 1930s. He devised a technique known as countercurrent distribution. The early experiments involved a line of separating funnels containing two immiscible solvents. After shaking the funnels, one of the liquid layers fi-om each funnel was transferred to the next in the line, and the process was repeated. Two solutes travelled at different rates if their partition coefficients for the two phases were different. Subsequently the separating funnels were replaced by special tubes, which meant that the process could be automated. 

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