Name: designed for molecular recycling: a lignin-derived semi-aromatic biobased polymer
Uploaded: 2020-11-30T14:00:00
Description: Watch this Scientific Journal Video about Designed for Molecular Recycling: A Lignin-Derived Semi-aromatic Biobased Polymer at JoVE.com

Los autores agradecen el apoyo financiero de la Organización Neerlandesa para la Investigación Científica (NWO) (subvención 023.007.020 otorgada a Jack van Schijndel).

1. Condensación de Knoevenagel verde de siringaldehído hacia ácido sinapínico con 5 mol% de bicarbonato de amonio
<ol><li>Agregue ácido malónico (20.81 g, 200.0 mmol) junto con siringaldehído (36.4 g, 200.0 mmol) a un matraz de fondo redondo de 250 ml. Disolver ambos constituyentes en 20,0 ml de acetato de etilo y añadir bicarbonato de amonio (790 mg, 10,0 mmol) al matraz. NOTA: Para garantizar la finalización completa de la reacción de condensación, el evaporador rotativo se puede utilizar para destilar ...

<ol>
	<li>Rahimi, A., Garc&#237;a, J. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Chemical+recycling+of+waste+plastics+for+new+materials+production.">Chemical recycling of waste plastics for new materials production.</a> Nature Reviews Chemistry. 1 (6), 41570 (2017).</li><li>Sardon, H., Dove, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Plastics+recycling+with+a+difference.">Plastics recycling with a difference.</a> Science. 360 (6387), 380-381 (2018).</li><li>Jones, G. O., Yuen, A., Wojtecki, R. J., Hedrick, J. L., Garc&#237;a, J. 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N., Hillmyer, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Renewable,+Degradable,+Chemically+Recyclable+Cross-Linked+Elastomers.">Renewable, Degradable, Chemically Recyclable Cross-Linked Elastomers.</a> Industrial &amp; Engineering Chemistry Research. 55 (42), 11097-11106 (2016).</li><li>Hong, M., Chen, E. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Completely+recyclable+biopolymers+with+linear+and+cyclic+topologies+via+ring-opening+polymerization+of+&#947;-butyrolactone.">Completely recyclable biopolymers with linear and cyclic topologies via ring-opening polymerization of &#947;-butyrolactone.</a> Nature Chemistry. 8 (1), 42-49 (2016).</li><li>Lochab, B., Shukla, S., Varma, I. 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M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biodegradable+polymers+for+use+in+surgery-poly(ethylene+oxide)+poly(ethylene+terephthalate)+(PEO/PET)+copolymers:+1.">Biodegradable polymers for use in surgery-poly(ethylene oxide) poly(ethylene terephthalate) (PEO/PET) copolymers: 1.</a> Polymer. 20 (12), 1454-1458 (1979).</li><li>Jiang, Y., Loos, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Enzymatic+Synthesis+of+Biobased+Polyesters+and+Polyamides.">Enzymatic Synthesis of Biobased Polyesters and Polyamides.</a> Polymers. 8 (7), 243 (2016).</li><li>Kricheldorf, H. R., Stukenbrock, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+polymer+syntheses,+92.+Biodegradable,+thermotropic+copolyesters+derived+from+&#946;-(4-hydroxyphenyl)propionic+acid.">New polymer syntheses, 92. Biodegradable, thermotropic copolyesters derived from &#946;-(4-hydroxyphenyl)propionic acid.</a> Macromolecular Chemistry and Physics. 198 (11), 3753-3767 (1997).</li><li>Kreye, O., Oelmann, S., Meier, M. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Renewable+Aromatic-Aliphatic+Copolyesters+Derived+from+Rapeseed.">Renewable Aromatic-Aliphatic Copolyesters Derived from Rapeseed.</a> Macromolecular Chemistry and Physics. 214 (13), 1452-1464 (2013).</li><li>Mialon, L., Pemba, A. G., Miller, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biorenewable+polyethylene+terephthalate+mimics+derived+from+lignin+and+acetic+acid.">Biorenewable polyethylene terephthalate mimics derived from lignin and acetic acid.</a> Green Chemistry. 12 (10), 1704 (2010).</li><li>Nguyen, H. T. H., Reis, M. H., Qi, P., Miller, S. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polyethylene+ferulate+(PEF)+and+congeners:+polystyrene+mimics+derived+from+biorenewable+aromatics.">Polyethylene ferulate (PEF) and congeners: polystyrene mimics derived from biorenewable aromatics.</a> Green Chemistry. 17 (9), 4512-4517 (2015).</li><li>van Schijndel, J., Canalle, L. A., Molendijk, D., Meuldijk, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Green+Knoevenagel+Condensation:+Solvent-free+Condensation+of+Benzaldehydes.">The Green Knoevenagel Condensation: Solvent-free Condensation of Benzaldehydes.</a> Green Chemistry Letters and Reviews. 10 (4), 404-411 (2017).</li><li>van Schijndel, J., Molendijk, D., Spakman, H., Knaven, E., Canalle, L. A., Meuldijk, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanistic+considerations+and+characterization+of+ammonia-based+catalytic+active+intermediates+of+the+Green+Knoevenagel+reaction+of+various+benzaldehydes.">Mechanistic considerations and characterization of ammonia-based catalytic active intermediates of the Green Knoevenagel reaction of various benzaldehydes.</a> Green Chemistry Letters and Reviews. 12 (3), 323-331 (2019).</li><li>Sheldon, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fundamentals+of+green+chemistry:+efficiency+in+reaction+design.">Fundamentals of green chemistry: efficiency in reaction design.</a> Chemical Society Reviews. 41 (4), 1437-1451 (2012).</li><li>van Schijndel, J., Molendijk, D., Canalle, L. A., Rump, E. T., Meuldijk, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temperature+Dependent+Green+Synthesis+of+3-Carboxycoumarins+and+3,4-unsubstituted+Coumarins.">Temperature Dependent Green Synthesis of 3-Carboxycoumarins and 3,4-unsubstituted Coumarins.</a> Current Organic Synthesis. 16 (1), 130-135 (2019).</li><li>Bloom, M. E., Vicentin, J., Honeycutt, D. S., Marsico, J. M., Geraci, T. S., Miri, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Highly+renewable,+thermoplastic+tetrapolyesters+based+on+hydroquinone,+p-hydroxybenzoic+acid+or+its+derivatives,+phloretic+acid,+and+dodecanedioic+acid.">Highly renewable, thermoplastic tetrapolyesters based on hydroquinone, p-hydroxybenzoic acid or its derivatives, phloretic acid, and dodecanedioic acid.</a> Journal of Polymer Science Part A: Polymer Chemistry. 56 (14), 1498-1507 (2018).</li><li>Padias, A. B., Hall, H. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanism+Studies+of+LCP+Synthesis.">Mechanism Studies of LCP Synthesis.</a> Polymers. 3 (2), 833-845 (2011).</li><li>Moon, S., Lee, C., Taniguchi, I., Miyamoto, M., Kimura, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Melt/solid+polycondensation+of+l-lactic+acid:+an+alternative+route+to+poly(l-lactic+acid)+with+high+molecular+weight.">Melt/solid polycondensation of l-lactic acid: an alternative route to poly(l-lactic acid) with high molecular weight.</a> Polymer. 42 (11), 5059-5062 (2001).</li><li>Wellen, R. M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+polystyrene+on+poly(ethylene+terephthalate)+crystallization.">Effect of polystyrene on poly(ethylene terephthalate) crystallization.</a> Materials Research. 17 (6), 1620-1627 (2014).</li><li>Kricheldorf, H. R., Conradi, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=New+polymer+syntheses+16.+LC-copolyesters+of+3-(4-hydroxyphenyl)+propionic+acid+and+4-hydroxy+benzoic+acids.">New polymer syntheses 16. LC-copolyesters of 3-(4-hydroxyphenyl) propionic acid and 4-hydroxy benzoic acids.</a> Journal of Polymer Science Part A: Polymer Chemistry. 25 (2), 489-504 (1987).</li><li>Chen, Y., Tan, L., Chen, L., Yang, Y., Wang, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Study+on+biodegradable+aromatic/aliphatic+copolyesters.">Study on biodegradable aromatic/aliphatic copolyesters.</a> Brazilian Journal of Chemical Engineering. 25 (2), 321-335 (2008).</li><li>Han, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+Change+in+Mechanism+from+Acidolysis+to+Phenolysis+in+the+Bulk+Copolymerization+of+4-Acetoxybenzoic+Acid+and+6-Acetoxy-2-naphthoic+Acid.">A Change in Mechanism from Acidolysis to Phenolysis in the Bulk Copolymerization of 4-Acetoxybenzoic Acid and 6-Acetoxy-2-naphthoic Acid.</a> Macromolecules. 29 (26), 8313-8320 (1996).</li><li>Lu, X. F., Hay, J. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isothermal+crystallization+kinetics+and+melting+behaviour+of+poly(ethylene+terephthalate).">Isothermal crystallization kinetics and melting behaviour of poly(ethylene terephthalate).</a> Polymer. 42 (23), 9423-9431 (2001).</li><li>S&#225;nchez, M. E., Mor&#225;n, A., Escapa, A., Calvo, L. F., Mart&#237;nez, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simultaneous+thermogravimetric+and+mass+spectrometric+analysis+of+the+pyrolysis+of+municipal+solid+wastes+and+polyethylene+terephthalate.">Simultaneous thermogravimetric and mass spectrometric analysis of the pyrolysis of municipal solid wastes and polyethylene terephthalate.</a> Journal of Thermal Analysis and Calorimetry. 90 (1), 209-215 (2007).</li></ol>

Cuando el ácido dihidroesinapínico se calentó en un recipiente de reacción, se produjo la sublimación del material de partida, y este efecto se mejoró cuando se aplicó un vacío. La acetilación se ha realizado sobre el ácido dihidroesinapínico para evitar la sublimación. Kricheldorf et al.12,27 reconocieron que no sólo se producía acetilación sino también di- y oligomerización de manera similar. Sin embargo, estos monómeros y oligómeros esterifi...

A diferencia de la incineración de residuos poliméricos, el reciclaje químico ofrece la posibilidad de recuperar los monómeros. El reciclaje químico es una elección lógica al final de la vida técnica de los materiales poliméricos, ya que estos materiales poliméricos se producen químicamente1. Existen dos formas de reciclar químicamente el material polimérico, la pirólisis y el reciclaje molecular2. Con la pirólisis, el material polimérico se transforma en productos de mayor valor mediante el uso de condicionesextremas3,4. El reciclaje molecular es un método eficiente para recuperar los materiales de partida mediante despolimerización. Después de la despolimerización, las unidades monoméricas pueden repolimerizarse en materiales poliméricos vírgenes5. La disponibilidad de monómeros adecuados para aplicar el reciclaje molecular a mayor escala es escasa. El problema actual del plástico dicta que la sociedad exige materiales poliméricos robustos y robustos. Al mismo tiempo, también se prefiere que los mismos materiales poliméricos sean fácilmente reciclables y no perduren en el medio ambiente. Los materiales poliméricos actuales con buenas propiedades térmicas y mecánicas no se despolimerizan fácilmente6.
La lignina, que se encuentra comúnmente en las plantas vasculares, es responsable del 30% del contenido natural de carbono del mundo y es el segundo biopolímero más abundante después de la celulosa. La lignina tiene una estructura amorfa compleja y parece ser una alternativa adecuada para reemplazar los aromáticos extraídos de materiales fósiles. La estructura tridimensional de la lignina proporciona resistencia y rigidez a la madera, así como resistencia a la degradación. Químicamente hablando, la lignina es un termoestable polifenólico muy complejo. Consiste en una composición variable de tres estructuras diferentes de fenilpropano metoxilato. Syringyl, guaiacyl y p-hydroxyphenyl (a menudo abreviados como S, G y H, respectivamente) se derivan de los monolignols alcohol sinapílico, alcohol coniferílico y alcohol p-cumarílico7. La distribución de estas unidades difiere según el tipo de biomasa, con madera blanda, por ejemplo, que consiste principalmente en unidades de guaiacyl y madera dura de guaiacyl y siringilo unidades8,9. Las fuentes naturales renovables, como los árboles y las plantas, son deseables para la producción de monómeros rediseñados para materiales poliméricos innovadores10. Estos monómeros, aislados y sintetizados a partir de fuentes naturales, son polimerizados a los llamados polímeros de base biológica11.
Los ácidos carboxílicos aromáticos son varios órdenes de magnitud menos electrofílicos que los ácidos carboxílicos alifáticos equivalentes por razones electrónicas12. Varios poliésteres comerciales utilizan ácidos carboxílicos aromáticos en lugar de ácidos carboxílicos alifáticos. Como resultado, las fibras en los textiles de poliéster hechos de fibras de poli(tereftalato de etileno) (PET) son casi insensibles a la hidrólisis durante el lavado o, por ejemplo, la lluvia13. Cuando se desea el reciclaje molecular de poliésteres, es aconsejable utilizar ésteres alifáticos en la acumulación del polímero.
Por las razones mencionadas, hemos investigado las posibilidades de hacer poliésteres a partir de ácidos 4-hidroxi-3,5-dimetoxi-dihidrocinámicos14. Estudios previos de Kricheldorf15,Meier 16y Miller17,18 muestran que es un desafío construir polímeros utilizando ácido 4-hidroxi-3,5-dimetoxi-dihidrocinámico. La descarboxilación y la reticulación dificultaron las polimerizaciones, limitando así el éxito de estas síntesis. Además, el mecanismo de la policondensación seguía sin estar claro. El documento presentado describe las condiciones en las que el poliéster (ácido dihidroesinapínico) se puede sintetizar regularmente y en alto rendimiento, allanando así el camino para el uso de poliésteres semiaromáticos que son molecularmente reciclables.
Hemos desarrollado una forma verde y eficiente de sintetizar ácido sinapínico utilizando una reacción de condensación entre siringaldehído y ácido malónico19,20. Después de este Knoevenagel verde, la hidrogenación produce ácido dihidrosinapínico, que es adecuado para la policondensación reversible. Esta publicación visualiza los pasos sintéticos al polímero molecularmente reciclable poli(ácido dihidrosinapínico), refiriéndose a las unidades base de lignina, llamadas poli-S. Después de analizar el material polimérico, el poli-S se despolimeriza al ácido dihidroesinapínico monómero en condiciones relativamente favorables y se repolimeriza una y otra vez.

<table>
	<tbody>
		<tr>
			<td>Reaction 1: Green Knoevenagel condensation</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Ammonium bicarbonate</td>
			<td>Sigma Aldrich</td>
			<td>&#62;99%</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol</td>
			<td>Boom</td>
			<td>Technical grade</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethyl acetate</td>
			<td>Macron</td>
			<td>99.8%</td>
			<td></td>
		</tr>
		<tr>
			<td>Hydrochloric acid</td>
			<td>Boom</td>
			<td>37%</td>
			<td></td>
		</tr>
		<tr>
			<td>Malonic acid</td>
			<td>Sigma Aldrich</td>
			<td>99%</td>
			<td>used as received</td>
		</tr>
		<tr>
			<td>Sodium bicarbonate</td>
			<td>Sigma Aldrich</td>
			<td>&#62;99.7%</td>
			<td></td>
		</tr>
		<tr>
			<td>Syringaldehyde</td>
			<td>Sigma Aldrich</td>
			<td>98%</td>
			<td>used as received</td>
		</tr>
		<tr>
			<td>Reaction 2: Hydrogenation</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Magnesium sulfate</td>
			<td>Macron</td>
			<td>99%</td>
			<td>dried</td>
		</tr>
		<tr>
			<td>Raney&#8482; nickel</td>
			<td>Sigma Aldrich</td>
			<td>&#62;89%</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium hydroxide</td>
			<td>Boom</td>
			<td>Technical grade</td>
			<td>dissolved</td>
		</tr>
		<tr>
			<td>Reaction 3: Acetylation</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Acetic anhydride</td>
			<td>Macron</td>
			<td>&#62;98%</td>
			<td></td>
		</tr>
		<tr>
			<td>Acetone</td>
			<td>Macron</td>
			<td>&#62;99.5%</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium acetate</td>
			<td>Sigma Aldrich</td>
			<td>&#62;99%</td>
			<td></td>
		</tr>
		<tr>
			<td>Reaction 4A: Polymerisation</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>1,2-xylene</td>
			<td>Macron</td>
			<td>&#62;98%</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium hydroxide</td>
			<td>Boom</td>
			<td>Technical grade</td>
			<td>finely powdered</td>
		</tr>
		<tr>
			<td>Zinc(II)acetate</td>
			<td>Sigma Aldrich</td>
			<td>99.99%</td>
			<td></td>
		</tr>
		<tr>
			<td>Reaction 4B: Depolymerisation</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium hydroxide</td>
			<td>Boom</td>
			<td>Technical grade</td>
			<td>dissolved</td>
		</tr>
		<tr>
			<td>Sulfuric acid</td>
			<td>Macron</td>
			<td>100%</td>
			<td></td>
		</tr>
		<tr>
			<td>Analysis</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>CDCl3</td>
			<td>Cambride Isotope Laboratories, Inc.</td>
			<td>99.5%</td>
			<td></td>
		</tr>
		<tr>
			<td>CF3COOD</td>
			<td>Cambride Isotope Laboratories, Inc.</td>
			<td>98%</td>
			<td></td>
		</tr>
		<tr>
			<td>Dimethylformamide</td>
			<td>Macron</td>
			<td>&#62;99.9%</td>
			<td></td>
		</tr>
		<tr>
			<td>Hexafluoro-2-propanol</td>
			<td>TCI Chemicals</td>
			<td>&#62;99%</td>
			<td></td>
		</tr>
		<tr>
			<td>Methanol</td>
			<td>Macron</td>
			<td>&#62;99.8%</td>
			<td></td>
		</tr>
		<tr>
			<td>Tetrahydrofuran</td>
			<td>Macron</td>
			<td>&#62;99.9%</td>
			<td></td>
		</tr>
	</tbody>
</table>

designed for molecular recycling: a lignin-derived semi-aromatic biobased polymer

El desarrollo de biopolímeros químicamente reciclables ofrece oportunidades dentro de la búsqueda de una economía circular. Los biopolímeros químicamente reciclables hacen un esfuerzo positivo para resolver el problema de los materiales poliméricos en la fase de eliminación después de la fase de uso. En este trabajo se describe y visualiza la producción de poliésteres semiaromáticos de base biológica, que pueden extraerse íntegramente de biomasa como la lignina. El polímero poly-S descrito en este documento tiene propiedades térmicas similares a ciertos plásticos de uso común, como el PET. Desarrollamos una reacción de Knoevenagel verde, que puede producir eficientemente monómeros a partir de aldehídos aromáticos y ácido malónico. Se ha demostrado que esta reacción es escalable y tiene un factor E calculado notablemente bajo. Estos poliésteres con ligno-fitoquímicos como punto de partida muestran un reciclaje molecular eficiente con pérdidas mínimas. El poliéster poli(ácido dihidrosinapinico) (poli-S) se presenta como un ejemplo de estos poliésteres semiaromáticos, y se describe la polimerización, despolimerización y repolimerización.

El ácido sinapínico se sintetizó en alta pureza y alto rendimiento (> 95%) a partir de siringaldehído utilizando la condensación green Knoevenagel. (Información de apoyo: Figura S1) El factor E es una indicación de la producción de residuos donde un número más alto indica más residuos. El factor E se calcula tomando la entrada total de material, restando la cantidad del producto final deseado y dividiendo el conjunto por la cantidad del producto final. Esta condensación de Green Knoevenagel t...

Watch this Scientific Journal Video about Designed for Molecular Recycling: A Lignin-Derived Semi-aromatic Biobased Polymer at JoVE.com

Designed for Molecular Recycling: A Lignin-Derived Semi-aromatic Biobased Polymer

Aquí se describe un ejemplo de un enfoque de circuito cerrado hacia una economía circular de materiales. Se presenta todo un ciclo sostenible donde los poliésteres semiaromáticos de base biológica se diseñan mediante polimerización, despolimerización y luego se repolimerizan con solo ligeros cambios en sus rendimientos o propiedades finales.

Diseñado para el reciclaje molecular: un polímero de origen biológico semiaromático derivado de la lignina

The development of chemically recyclable biopolymers offers opportunities within the pursuit of a circular economy. Chemically recyclable biopolymers make ...

Throughout the synthesis described in this paper provides a way to produce a new polymeric material specifically designed for molecular recycling, which is a way of chemical recycling. The depolarization and repolarization of the foreign material poly-S creates a fully sustainable cycle, which is a proof of concept for the future of polymers. The polymer waste of the world accumulates.For instance in the ocean, as the plastic soup, which could be prevented by introducing molecularly recyclable polymers. The polymer presented is an example of a polymeric material designed for molecular recycling. This in our opinion, should be implemented in other materials to prevent accumulation in nature.Green Knoevenagel reaction and subsequent steps have been designed for and by our undergraduated students. So certain robustness is already implemented in these reaction steps. The COVID-19 pandemic creates a situation where online learning becomes more important than ever.Visualization of these experiments helps us and others to deepen practical chemical education. Begin by adding 20.81 grams of malonic acid and 36.4 grams of syringaldehyde to a 215 milliliter round bottom flask. Dissolve both constituents in 20 milliliters of ethyl acetate and add 719 milligrams of ammonia bicarbonate to the flask.Mix and distill the solvent with a water bath. Keep the reaction mixture at 90 degrees Celsius for two hours in the open flask without stirring for complete conversion to sinapinic acid. In the work-up of the sinapinic acid product, dissolve the residue in 100 milliliters of a saturated aqueous sodium bicarbonate solution, then transfer the solution to a beaker, and acidify it to a pH two.Using six molar hydrogen chloride, separate the resulting residue by vacuum filtration and wash it with demineralized water. Charge a 450 milliliters flask with 33.6 grams sinapinic acid. Dissolve the sinapinic acid in 300 milliliters of two molar sodium hydroxide solution, and add 1.5 grams of nickel slurry before fitting the flask to the operators.Pressurize the reactor with three bar of hydrogen gas and mechanically shake the reaction at 80 degrees Celsius for three hours. Cool the reactor to room temperature and depressurize slowly. Recover most of the nickel catalyst with a magnet, then filter the solution.Acidify the solution with four molar hydrogen chloride solution to a pH of two, then perform an extraction with ethyl acetate. Remove the solvent under reduced pressure after drying over magnesium sulfate and dry the dihydrosinapinic acid at 60 degrees Celsius in a vacuum oven. Add 22.6 grams dihydrosinapinic acid to a 250 milliliter round bottom flask.Followed by 14.2 milliliters of acetic anhydride and 0.82 grams of sodium acetate. Heat the solution to 90 degrees Celsius while stirring for one hour for complete conversion of dihydrosinapinic acid to 4-Acetoxy-dihydrosinapinic acid, and it's acetylated oligomers. Dissolve the solid in 25 milliliters of acetone precipitated into 250 milliliters of 0.1 molar hydrogen chloride, then filtered on the vacuum.Add the monomers 20.8 grams of 4-Acetoxy-dihydrosinapinic acid and prepolymer to a 100 milliliter round bottom flask. Then add 400 milligrams of finely powdered sodium hydroxide, heat the reaction mixture for three hours at a set temperature of 140 degrees Celsius in the open flask while staring at 100 RPM. Set up a solvent assisted polymerization by adding 180 milligrams of zinc two acetate and 25.0 milliliters of 1, 2-xylene to the flask, then raise the set temperature to 160 degrees Celsius.Reflux the mixture at 144 degrees Celsius for three hours with constant water and acetic acid removal using Dean-Stark head. Cool the reaction mixture down and remove the 1, 2-xylene by applying a vacuum. Raise the temperature to 240 degrees Celsius during the final stage of the polymerization and apply a high vacuum for 30 minutes.Cool the polymer poly-S to room temperature and wash it with methanol to eliminate dihydrogen sinapinic acid and prepolymers. The obtained product should be a light brown solid. Finally grind and serve the poly-S into particles smaller than 180 micrometres to measure hydrolytic degradation.Load several test tubes with 20 milligrams of poly-S and add one milliliter of one molar sodium hydroxide solution. Incubate the tubes at three different temperatures with an agitation of 500 RPM. Neutralize the test tubes at regular time intervals with one milliliter of 0.5 molar sulfuric acid, and add two milliliters of methanol after cooling.Filter all samples using 0.45 micro meter PTFE syringe filters and inject 20 microliters into HPLC using an auto sampler. Monitor the absorbance at 254 nanometers and calculate the concentrations from a calibration curve of known dihydrosinapinic acid standard solutions. Sinapinic acid was synthesized in high purity and a greater than 95%yield from syringaldehyde using the Green Knoevenagel Condensation, the proposed mechanism of the step growth polymerization of 4-Acetoxy-dihydrosinapinic acid is shown here.Hydrogen one and MR measurements were taken during the polymerization process. When poly-S was hydrolyzed in sodium hydroxide, the molecularly recyclable polyester yielded the starting material dihydrosinapinic acid in less than 10 minutes. As confirmed by HBLC melting point analysis and hydrogen one and MR.Extended reaction times did not increase the yield.The thermal grams and GPC analysis of poly-S 1.0 and their successive generations poly-S 2.0 and polyester 3.0 after forced amorphicity with a tactic polystyrene are shown here. DSC analysis of poly-S shows a glass transition signal at 113 degrees Celsius and endothermic melting signal at 281 degrees Celsius. The polymers from re-polymerized sinapinic acid three eight poly-S 2.0 up and poly-H 3.0 exhibit similar thermal properties.Poly-S is a semi crystalline polymeric material because glass transition temperatures and melting signals are present in the thermograms of poly-S and their successive generations. GPC analysis after forced amorphicity with a tactic polystyrene displays a constant length of polymeric material throughout the different generations. While attempting the Green Knoevenagel reaction, please keep in mind that a correct temperature is used.A slightly higher temperature can lead to different site reactions. We have explored an example of a molecularly recyclable polymer. Closely related building blocks can follow the same procedure, or while maintaining thermal and mechanical properties.This method can be used in organic catalysis by demonstrating of the catalytic intermediates, as well in the still unexplored area of molecular recycling.

Research

Education

JoVE Core

JoVE Journal

Organic Chemistry

Chemistry

Unit 1

&alpha;-Carbon Chemistry: Enols, Enolates, and Enamines

SCIENTISTS IN ACTION

Gyroid Nickel Nanostructures from Diblock Copolymer Supramolecules

Gyroid Níquel Nanoestructuras de copolímero de dibloques supramoléculas

Nanoporous metal foams possess a unique combination of properties - they are catalytically active, thermally and electrically conductive, and furthermore, ...

Investigación

Química

Preparation of Highly Porous Coordination Polymer Coatings on Macroporous Polymer Monoliths for Enhanced Enrichment of Phosphopeptides

Preparación de altamente poroso Coordinación Polymer Coatings en macroporosas Polymer Monolitos de Enriquecimiento mejorada de Phosphopeptides

We describe a protocol for the preparation of hybrid materials based on highly porous coordination polymer coatings on the internal surface of macroporous ...

Photodynamic Therapy with Blended Conducting Polymer/Fullerene Nanoparticle Photosensitizers

Terapia fotodinámica con Blended polímero conductor / Fullerene nanopartículas fotosensibilizadores

In this article a method for the fabrication and reproducible in-vitro evaluation of conducting polymer nanoparticles blended with fullerene as the next ...

Functionalization of Single-walled Carbon Nanotubes with Thermo-reversible Block Copolymers and Characterization by Small-angle Neutron Scattering

Funcionalización de pared simple nanotubos de carbono con Thermo-reversibles copolímeros de bloque y Caracterización de ángulo pequeño dispersión de neutrones

We demonstrate a protocol for single-walled carbon nanotube functionalization using thermo-sensitive PEO-PPO-PEO triblock copolymers in an aqueous ...

The Preparation and Properties of Thermo-reversibly Cross-linked Rubber Via Diels-Alder Chemistry

La preparación y propiedades de termo-reversible reticulado Química Caucho Vía de Diels-Alder

A method for using Diels Alder thermo-reversible chemistry as cross-linking tool for rubber products is demonstrated. In this work, a commercial ...

Direct Imaging of Laser-driven Ultrafast Molecular Rotation

Direct Imaging del impulsada por el láser ultrarrápido Molecular Rotación

We present a method for visualizing laser-induced, ultrafast molecular rotational wave packet dynamics. We have developed a new 2-dimensional Coulomb ...

Microfluidic Dry-spinning and Characterization of Regenerated Silk Fibroin Fibers

Seco de microfluidos-spinning y caracterización de las fibras regeneradas fibroína de seda

The protocol demonstrates a method for mimicking the spinning process of silkworm. In the native spinning process, the contracting spinning duct enables ...

Electrochemical Impedance Spectroscopy as a Tool for Electrochemical Rate Constant Estimation

Espectroscopia de impedancia electroquímica como herramienta para la valoración constante de tipo electroquímico

Electrochemical impedance spectroscopy (EIS) was used for advanced characterization of organic electroactive compounds along with cyclic voltammetry (CV). ...

Time-resolved Photophysical Characterization of Triplet-harvesting Organic Compounds at an Oxygen-free Environment Using an iCCD Camera

Tiempo-resolved fotofísicas caracterización de trío cosecha compuestos orgánicos en un libre de oxígeno ambiente usando un iCCD cámara

Here, we present a sensible method of the acquisition and analysis of time-resolved photoluminescence using an ultrafast iCCD camera. This system enables ...