High-gravity fields

Excellent heat and mass transfer characteristics of the SDR have been confirmed by the study of a phase-transfer-catalyzed Darzens reaction for preparing a drug intermediate. The SDR allowed for a 99.9% reduction in reaction time, 99% reduction of inventory and 93% reduction in the level of impurities [106]. Other possible applications of the SDR include polymerizations and polycondensations (in both cases considerable time savings and more uniform product) as well as precipitation/crystallization (smaller crystals with much narrower size distribution). Two large chemical companies have patented processes based on spinning-disc technology. SmithKline Beecham has claimed a method to epoxidize substituted 

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Trent, D. (2004) Chemical processing in high-gravity fields, in Re-Engineering the Chemical Processing Plant Process Intensification (eds A. Stankiewicz and J.A. Moulijn), Marcel Dekker Inc., New York, pp. 33-67. 

Reactive crystallization, or precipitation, has been investigated by numerous research groups. Processes of industrial relevance include liquid-phase oxidation of para-xylene to terephthalic acid, the acidic hydrolysis of sodium salicylate to salicylic acid, and the absorption of ammonia in aqueous sulfuric acid to form ammonium sulfate (60). A very special type of reactive crystallization is diastereomeric crystallization, widely applied in the pharmaceutical industry for the resolution of enantiomers (61). Another fine example of reactive precipitation is the earlier-described production of nano-size particles of CaC03 in high-gravity fields (46). 

Before exploring the wide range of applications, a brief review of the history of development, a discussion of the process fundamentals, and an introduction to mechanical design issues will help to set the boundaries for use of high-gravity fields in chemical processing. 

High-gravity field Spinning disc reactor Heat transfer from liquid film Mass transfer in liquid film Reaction time Equipment size Impurities level... 

Ma L, Cheng M, Jia G, Wang Y, An Q, Zeng X, et al. Layer-by-layer self-assembly under high gravity field. Langmuir 2012 28(25) 9849—56. 

In recent years, a variety of experiments in high gravity fields have received much attention from a broad area in science and technology. The forces of 2-10 g can be generated for short time of 10 -10 s in beginning and ending periods of... 

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