Mathematical modeling of aldol addition in different types of reactors

U ovom radu je numerički na temelju razvijenog modela implementiranog u programu SCIENTIST, ispitivana aldolna adicija dihidroksiacetona na N-Cbz-3-aminopropanala koju katalizira enzim D – fruktoza – 6 – fosfat aldolaza (FSA). Isto tako je istraživana ova reakcija spojena s oksidacijom N-Cbz-3-aminopropanola u N-Cbz-3-aminopropanala u kaskadnu reakciju. Oksidacija alkohola koju katalizira alkohol dehidrogenaza (ADH), je provedena uz regeneraciju koenzima NAD+ s enzimom NADH oksidaza. Modeli su razvijeni za šaržni, kotlasto protočni i reaktor s dotokom. Potrebni kinetički parametri su uzeti iz literature. Dobiveni rezultati pokazuju da konverzija mjerodavnog reaktanta u šaržnom reaktoru kod aldolne adicije ovisi o količini FSA enzima, te o početnom omjeru dva reaktanta Konverzija u protočno kotlastom reaktoru raste s vremenom zadržavanja, a u reaktoru s dotokom konverzija s povećanjem brzine dotoka opada. U kaskadnoj reakciji oksidacija alkohola plus aldolna adicija, iskorištenje na aldolu u šaržnom reaktoru raste s povećanjem koncentracije dihidroksiacetona, a opada s povećanjem koncentracije alkohola. Iskorištenje ovisi o stabilnosti enzima u reakcijama. Iskorištenje na aldolu ovisi o vremenu zadržavanja u kotlasto protočnom reaktoru, a o brzini dotoka u reaktoru s dotokom. Najveće iskorištenje na aldolu je moguće ostvariti u šaržnom reaktoru uz suvišak dihidroksiacetona.In this work, with developed model in SCIENTIST, aldol addition of dihydroxyacetone (DHA) to N-Cbz-3-aminopropanal, which is catalyzed by enzyme D-fructose-6-phosphate aldolase (FSA), is numerical examined. Also this reaction connected with oxidation N-Cbz-3- aminopropanola in N-Cbz-3-aminopropanal is study in cascade reaction. Oxidation of alcohol, which is catalyzed by alcohol dehydrogenaese (ADH), is examined with regeneration coenzyme NAD+ with enzyme NADH oxidase. Models are developed for batch,fed-batch and continuously stirred tank (CSTR) reactor. Kinetic parameters were taken from literature. Results are demonstrating that conversion of limited reactant in batch reactor in aldol addition depends on concentration of FSA enyzme and on starting ratio of two reactants. Conversion in CSTR increases with residence time and in fed-batch reactor it decreases when the flow is growing. In cascade reaction, oxidation of alcohol plus aldol addition, yield on aldol in batch reactor increases when the concetration of dihydroxyacetone increases and it decreases when the concetration of alcohol increases. Yield of the reaction depend on stability of enzymes. Yield on aldol depends on residence time in CSTR and in fed-batch reactor it depends on the flow. The maximum yield on aldol is possible to reach in batch reactor with excess of dihydroxyacetone (DHA)