engleski

Effect of different flow ratios of two immiscible liquid-liquid phases on hexanol oxidation in microreactor

Due to their many advantages comparing to classical reactors, microreactors are finding wide area of applications, from chemical synthesis to biotransformations. They are also being widely investigated for applications in fine chemical and pharmaceutical industries as alternative to classical processes. Important area of microreactors application are enzyme catalyzed biotransformations.1 In this work alcohol dehydrogenase catalyzed hexanol oxidation to hexanal2 was preformed in tubular microreactor with internal volume of 6 L. Introducing two immiscible phases (water and organic phase) into the microreactor segmented or slug flow was formed. It is characterized by alternating aqueous and organic segments.3 Changing the flow ratios of individual phases, flow pattern is altered. In this work effect of six combinations of different flow ratios of water and organic phases (1:3, 1:5, 1:10, 3:1, 5:1 and 10:1) on hexanol oxidation was analyzed. All experiments were made with same inlet concentrations of enzyme and coenzyme (ci, NAD+=0, 55 mmol dm-3, ci, ADH=0, 092 g dm-3). Introducing equal amounts of water and organic phase in tubular microreactor it was noticed that conversion increases with prolongation of residence time. After 72 s conversion on 13.5 % was obtained. The same effect was noticed when conducting reaction with flow ratios 1:3, 1:5 and 1:10. Obtained conversions are approximately the same at all three tested flow rates. In experiments performed at flow rates ratios of 3:1, 5:1 and 10:1 the best results were obtained when 3:1 flow ratio was used. For low residence times obtained conversions were approximately two times higher then when equal amounts of both phases were introduced into the microreactor.

microreactor; hexanol oxidation; immiscible liquids; segmented flow

Ovaj se tekst temelji na radu koji je financirala Nacionalna zaklada za znanost, visoko školstvo i tehnologijski razvoj Republike Hrvatske.