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Inline analytical supported process development towards alternative bio-based plasticizers
Citation Link: https://doi.org/10.15480/882.4039
Publikationstyp
Doctoral Thesis
Date Issued
2021
Sprache
English
Author(s)
Advisor
Referee
Title Granting Institution
Technische Universität Hamburg
Place of Title Granting Institution
Hamburg
Examination Date
2021-07-01
Institut
TORE-DOI
Citation
Technische Universität Hamburg (2021)
Polyvinyl chloride (PVC) is nowadays the third most applied polymer with approximately 41 million tons produced in 2017. Plasticizers are added to the PVC polymer to increase the flexibility. The most common class of plasticizers are ortho-phthalic acid esters (phthalates). In the last years, the application of some of the latter was restricted due to health concerns. Therefore, the need for non-harmful alternatives arises. Additionally, bio-based plasticizer are a promising approach, since these will decrease the overall carbon footprint of the plasticized polymer.
In this thesis, a three-step process is developed to produce bio-based plasticizers in a multi-gram scale using renewable resources as basis. Starting from 2-methylfuran and maleic acid anhydride, in a Diels-Alder reaction, a cyclic 6-membered ring intermediate for the plasticizing building block (1st step) is synthesized. This instable intermediate tends to undergo a retro-Diels Alder reaction and need to be stabilized via hydrogenation prior to further reaction steps avoiding the backwards reaction (2nd step). In a 3rd step, the cyclic plasticizer building block was successfully esterified at its acid groups in ortho-position. Here, 2-ethylhexanol, a standard alcohol applied in the synthesis of various plasticizers, is used. Additionally, the applicability of more than 80 enzymes for a biocatalytic esterification step was investigated. Throughout this work, inline analytic was employed for the characterization of the respective reaction steps. In detail, Fourier-transformed Infrared spectroscopy (FTIR) equipped with Attenuated Total Reflection (ATR) probes was implemented. These probes enable a non-destructive analysis directly inside the reactor vessel. To derive the respective concentrations from the recorded vibrational spectra, chemometric models were developed. In this work, the Indirect Hard Modeling (IHM) as a physically motivated hard modeling approach was applied. Besides using these established inline analytical methods in terms of process characterization, the inline measured data were used to set up kinetic models describing the each single reaction step. For this reason, the inline data were fitted to inline measured concentration profiles yielding the respective reaction rate constants.
Concluding, in this thesis a promising approach for inline analytical-supported process development towards bio-based plasticizer is presented. Moreover, this approach can be transferred to other potential plasticizer candidates helping to reduce the time needed for the process development.
In this thesis, a three-step process is developed to produce bio-based plasticizers in a multi-gram scale using renewable resources as basis. Starting from 2-methylfuran and maleic acid anhydride, in a Diels-Alder reaction, a cyclic 6-membered ring intermediate for the plasticizing building block (1st step) is synthesized. This instable intermediate tends to undergo a retro-Diels Alder reaction and need to be stabilized via hydrogenation prior to further reaction steps avoiding the backwards reaction (2nd step). In a 3rd step, the cyclic plasticizer building block was successfully esterified at its acid groups in ortho-position. Here, 2-ethylhexanol, a standard alcohol applied in the synthesis of various plasticizers, is used. Additionally, the applicability of more than 80 enzymes for a biocatalytic esterification step was investigated. Throughout this work, inline analytic was employed for the characterization of the respective reaction steps. In detail, Fourier-transformed Infrared spectroscopy (FTIR) equipped with Attenuated Total Reflection (ATR) probes was implemented. These probes enable a non-destructive analysis directly inside the reactor vessel. To derive the respective concentrations from the recorded vibrational spectra, chemometric models were developed. In this work, the Indirect Hard Modeling (IHM) as a physically motivated hard modeling approach was applied. Besides using these established inline analytical methods in terms of process characterization, the inline measured data were used to set up kinetic models describing the each single reaction step. For this reason, the inline data were fitted to inline measured concentration profiles yielding the respective reaction rate constants.
Concluding, in this thesis a promising approach for inline analytical-supported process development towards bio-based plasticizer is presented. Moreover, this approach can be transferred to other potential plasticizer candidates helping to reduce the time needed for the process development.
Subjects
Bio-based plasticizers
Process development
Inline analytic
Infrared vibrational spectroscopy
Indirect Hard Modelling
DDC Class
570: Biowissenschaften, Biologie
600: Technik
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