Integration of Wiped-Film Evaporation and Crossflow Microfiltration for the Purification of a Silylenol Ether Reaction Mixture: Process Issues and Scaleup

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• 作者：Karen A. Larson ; A. Andrews ; B. Snyder ; C. Wightman ; and E. Paul
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：1996
• 出版时间：April 1996
• 年：1996
• 卷：35
• 期：4
• 页码：1322 - 1331
• 全文大小：363K
• 年卷期：v.35,no.4(April 1996)
• ISSN：1520-5045

文摘

The reaction between p-nitrobenzyl 2-diazoacetoacetateand trimethylchlorosilane (TMS-Cl)produces a toluene-soluble silylenol ether (SEE) product and insolublebyproduct salts (NaCland triethylammonium hydroiodide). Purification of the SEEsolution via removal of the saltsand unreacted TMS-Cl is accomplished by integrating two unit operations[crossflow microfiltration and distillation in a wiped-film evaporator (WFE)] into asemicontinuous process. Theprocess addresses the critical scale-up issues of potential exothermicactivity near the operatingtemperature, water sensitivity of the product, and the avoidance ofdirect solids handling. Keyto its successful scaleup from the laboratory (2 kg scale) tomanufacturing (370 kg scale) wasthe development of a distributed control system which addressescharacteristics unique to eachof the unit operations. Crossflow operation at all scalesexhibited a substantial increase andthen a decrease in transmembrane pressure (TMP) which coincided withdissolved solidsconcentration and concomitant solution viscosity. Membranefouling, which became apparentin manufacturing after repeated membrane use, was addressed byoperational changes tominimize TMP and by incorporating a membrane cleaningprocedure.