Enzymatic synthesis of geranyl acetate in packed bed reactor in supercritical carbon dioxide under various pressure-temperature conditions and reactor configurations

Abstract

Data in this paper describes the catalytic performances, expressed in terms of conversion %, of geraniol and acetic acid to geranyl acetate, using the immobilized lipase B from Candida antarctica in packed bed reactors (PBR) using supercritical CO 2 as a solvent. Readers will find data related to different Figures or equations of the article as well as supplementary data that will help to make the difference between flowrates of CO 2 in a liquid state and corresponding flowrates of supercritical CO 2 for various CO 2 pressure and temperature combinations.

Non-covalent and covalent immobilization of Candida antarctica lipase B on chemically modified multiwalled carbon nanotubes for a green acylation process in supercritical CO2

“…After cycling, cCAL-B@MWCNT, showed a stabilized residual TOF of 4.1 moles of geranyl acetate.mole -1 of CAL-B.min -1 , while twice lower and non-stabilized TOF was achieved with non-covalent binding. When comparing these data with data obtained previously by Bourkaib et al 18 in similar operating conditions but using 300 mg of Lipozyme 435 beads (10.08 % w:w of CAL-B according to dos Santos et al 35 ), it was observed a significantly higher TOF of 62.7 moles of geranyl acetat.mole -1 of CAL-B.min -1 , expected for this commercial meso-macroporous catalyst. Furthermore, development of new biocatalysts using CNTs as support on which CAL-B was covalently or non-covalently immobilized has emerged over the past few years.…”

“…In addition, and despite the lower TOF achieved in this study with MWCNTs as carriers versus what was achieved by other authors such as Bourkaib et al with commercial polymeric macroporous beads 18 , it is of great importance to underline the specificity of the present process as compared to the ones observed from literature and also using MWCNTs as carriers. Indeed, when using continuous processing with a packed bed reactor, it was actually not required to perform cycling because reaction products and substrates and CO2 are continuously removed from the reactor at the level of the back-pressure regulator-separator.…”

“…Products (geranyl acetate and some traces of water) and unreacted substrates (geraniol and acetic acid) were collected in 60 mL amber vials at the exit of the back pressure regulator (BPR). For sample collection at atmospheric pressure all along the reaction, and as described in Bourkaib et al a home-made CO2 flow breaker was used for breaking CO2 flow while allowing desolubilized products and unreacted substrates to flow in a liquid form along the internal walls of the flow breaker 18 . This flow breaker system was placed just above, and not inside the collecting tube, so that CO2 can be easily eliminated in the atmosphere.…”

“…Besides, MWCNTs have a high mechanical and thermal resistance but low internal porosity compared to polymetacrylate-based polymers for example, which could also favor CAL-B leaching. Catalytic performances of the prepared biocatalysts (ncCAL-B@MWCNT and cCAL-B@MWCNT) were compared with those of a commercial lipase immobilized on polymeric mesomacroporous beads (Lipozyme 435) achieved under scCO2 in the reactor using the same operating conditions 18 . In that former study, the reactor was filled with 300 mg of Lipozyme 435 beads (corresponding to 1 mL bulk volume) and 36 % conversion had been achieved without any change over 6 consecutive running cycles.…”

“…CRL was shown to catalyze the regioselective acylation of methyl 6-O-trityl b-dglucopyranoside in scCO2 with a conversion rate as high as 91.4 % 17 . Conversions of 83 % and 98 % were observed for the synthesis of geranyl acetate catalyzed by CAL-B in scCO2 18 . Even if more investigation is needed to better understand the precise involved mechanisms between the scFs and the biocatalyst, it has been normally observed that the reaction selectivity was preserved and the reaction rate was increased in scFs compared to other solvents.…”