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

Yazarlar, Hollanda Bilimsel Araştırma Örgütü'nün (NWO) finansal desteği için minnettardır (Jack van Schijndel'e verilen 023.007.020 hibe).

1. Yeşil Knoevenagel yoğuşması şırındaldehit doğru sinapinik asit ile 5 mol% amonyum bikarbonat
<ol><li>250 mL yuvarlak alt şişeye şırındaldehit (36,4 g, 200,0 mmol) ile birlikte malonik asit (20,81 g, 200,0 mmol) ekleyin. Her iki bileşeni de 20,0 mL etil asetat içinde çözün ve şişeye amonyum bikarbonat (790 mg, 10,0 mmol) ekleyin. NOT: Yoğuşma reaksiyonunun tam olarak tamamlanmasını sağlamak için, döner evaporatör etil asetat ve reaksiyon karışımını konsantre etmek için kullanılab...

<ol>
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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>

Dihidrosinapinik asit bir reaksiyon kabında ısıtıldığında, başlangıç malzemesinin süblimasyonu meydana geldi ve vakum uygulandığında bu etki arttı. Süblimasyonu önlemek için dihidrosinapinik asit üzerinde asetilasyon yapıldı. Kricheldorf ve ark.12,27 sadece asetilasyon değil, aynı zamanda di- ve oligomerizasyonun meydana geldiğini kabul etti. Bununla birlikte, bu esterleşmiş monomerler ve oligomerler artık sublimate değildir ve eriyik ...

Polimerik atıkların yakılmasının aksine, kimyasal geri dönüşüm monomerleri geri kazanma imkanı sunar. Kimyasal geri dönüşüm, polimerik malzemelerin teknik ömrünün sonunda mantıklı bir seçimdir, çünkü bu polimerik malzemeler kimyasal olarak üretilir1. Polimerik malzemeyi kimyasal olarak geri dönüştürmenin iki yolu vardır, piroliz ve moleküler geri dönüşüm2. Piroliz ile polimerik malzeme, aşırı koşullar kullanılarak daha yüksek değerli ürünlere dönüştürülür3,4. Moleküler geri dönüşüm, depolimerizasyon kullanarak başlangıç malzemelerinin geri kazanılması için etkili bir yöntemdir. Depolimerizasyondan sonra, monomerik üniteler bakir polimerik malzemelere yeniden dönüştürülebilir5. Moleküler geri dönüşümü daha büyük ölçekte uygulamak için uygun monomerlerin mevcudiyeti istiyor. Mevcut plastik sorun, toplumun sağlam ve sağlam polimerik malzemeler talep ettiğini dikte ediyor. Aynı zamanda, aynı polimerik malzemelerin kolayca geri dönüştürülebilir olması ve ortamda dayanmaması da tercih edilir. İyi termal ve mekanik özelliklere sahip akım polimerik malzemeler kolayca depolimerize olmaz6.
Genellikle vasküler bitkilerde bulunan Lignin, dünyadaki doğal karbon içeriğinin% 30'undan sorumludur ve selülozdan sonra en bol ikinci biyopolimerdir. Lignin karmaşık bir amorf yapıya sahiptir ve fosil malzemelerden çıkarılan aromatiklerin yerini almak için uygun bir alternatif olarak görünmektedir. Lignin üç boyutlu yapısı ahşaba mukavemet ve sertlik sağlamanın yanı sıra bozulmaya karşı direnç sağlar. Kimyasal olarak konuşursak, lignin çok karmaşık bir polifenolik termosettir. Üç farklı metoksillenmiş fenilpropan yapının farklı bileşimlerinden oluşur. Syringyl, guaiacyl ve p-hydroxyphenyl (genellikle sırasıyla S, G ve H olarak kısaltılır) monolignols sinapil alkol, iğne yapraklı alkol ve p-coumaryl alkol7türetilmiştir. Bu birimlerin dağılımı biyokütle tipine göre farklılık gösterir, örneğin yumuşak ağaç, çoğunlukla guaiacyl üniteleri ve guaiacyl ve şırıng ünitelerinin sert odunlarından oluşan8,9. Ağaçlar ve bitkiler gibi yenilenebilir doğal kaynaklar, yenilikçi polimerik malzemeler için yeniden tasarlanmış monomerlerin üretimi için arzu edilir10. Doğal kaynaklardan izole edilen ve sentezlenen bu monomerler, biyobaz polimerler11olarak adlandırılır.
Aromatik karboksilik asitler, elektronik nedenlerle eşdeğer alifatik karboksilik asitlerden daha az elektrofilik büyüklükteki birkaç sipariştir12. Çeşitli ticari polyesterler alifatik karboksilik asitler yerine aromatik karboksilik asitler kullanır. Sonuç olarak, poli(etilen tereftalat) (PET) liflerinden yapılan polyester tekstillerdeki lifler yıkama sırasında hidroliz veya örneğin yağmur13'eneredeyse duyarsızdır. Polyesterlerin moleküler geri dönüşümü istendiğinde, polimerin birikmesinde alifatik esterlerin kullanılması tavsiye edilir.
Bahsedilen nedenlerden dolayı, 4-hidroksi-3,5-diethoxy-dihidrosinnamik asitlerden polyester yapma olasılıklarını araştırdık14. Kricheldorf15, Meier16ve Miller17,18 tarafından yapılan öncekiçalışmalar,4-hidroksi-3,5-diethoxy-dihidrosinnamik asit kullanarak polimerler inşa etmenin zor olduğunu göstermektedir. Dekarboksilasyon ve çapraz bağlama polimerizasyonları engelledi ve böylece bu sentezlerin başarısını sınırladı. Ayrıca, polikondansasyonun mekanizması belirsizliğini korudu. Sunulan makale, polyester polisinin (dihidrosinapinik asit) düzenli ve yüksek verimde sentezlenebildiği koşulları açıklar, böylece moleküler olarak geri dönüştürülebilir yarı aromatik polyesterlerin kullanılmasının yolunu açmaktadır.
Şırındaldehit ve malonik asit arasında yoğuşma reaksiyonunu kullanarak sinapinik asidi sentezlemenin yeşil ve verimli bir yolunu geliştirdik19,20. Bu Yeşil Knoevenagel'den sonra hidrojenasyon, geri dönüşümlü polikondansasyon için uygun olan dihidrosinapinik asit üretir. Bu yayın, poli-S adı verilen lignin temel birimlerine atıfta bulunarak moleküler olarak geri dönüştürülebilir polimer polimeri (dihidrosinapinik asit) için sentetik adımları görselleştirir. Polimerik malzeme analiz edildikten sonra, poli-S nispeten uygun koşullar altında monomer dihidrosinapinik aside depolimerize edilir ve tekrar tekrar repolimerize edilir.

<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

Kimyasal olarak geri dönüştürülebilir biyopolimerlerin geliştirilmesi, döngüsel bir ekonomi arayışında fırsatlar sunmaktadır. Kimyasal olarak geri dönüştürülebilir biyopolimerler, kullanım aşamasından sonra bertaraf aşamasında polimer malzemeler sorununu çözmek için olumlu bir çaba sarf eder. Bu yazıda lignin gibi biyokütleden tamamen çıkarılabilen biyobazlı yarı aromatik polyesterlerin üretimi açıklanmış ve görselleştirilmiştir. Bu makalede açıklanan polimer poli-S, PET gibi yaygın olarak kullanılan bazı plastiklere benzer termal özelliklere sahiptir. Aromatik aldehitler ve tonik asitten monomerleri verimli bir şekilde üretebilen yeşil bir Knoevenagel reaksiyonu geliştirdik. Bu reaksiyonnun ölçeklenebilir olduğu kanıtlanmıştır ve oldukça düşük hesaplanmış bir E faktörüne sahiptir. Başlangıç noktası ligno-fitokimyasallara sahip bu polyesterler, en az kayıpla verimli bir moleküler geri dönüşüm göstermektedir. Polyester poli(dihidrosinapinik asit) (poli-S) bu yarı aromatik poliesterlere örnek olarak sunulmuştur ve polimerizasyon, depolimerizasyon ve yeniden polimerizasyon açıklanmaktadır.

Sinapinik asit, Yeşil Knoevenagel yoğuşması kullanılarak şırındyaldehitten yüksek saflıkta ve yüksek verimde (%> 95) sentezlendi. (Destekleyici Bilgiler: Şekil S1) E-faktörü, daha yüksek bir sayının daha fazla israfı gösterdiği atık üretiminin bir göstergesidir. E faktörü, toplam malzeme girişi alınarak, istenen son ürün miktarı çıkarılarak ve tamamının son ürün miktarına bölünmesiyle hesaplanır. Bu Yeşil Knoevenagel yoğuşması 1.0 E faktörüne sahiptir. hesap...

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

Döngüsel malzeme ekonomisine yönelik kapalı döngü yaklaşımının bir örneği burada açıklanmıştır. Biyobazlı yarı aromatik polyesterlerin polimerizasyon, depolimerizasyon ve daha sonra verimlerinde veya nihai özelliklerinde sadece küçük değişikliklerle yeniden polimerize edildiği bir bütün sürdürülebilir döngü sunulmaktadır.

Moleküler Geri Dönüşüm için Tasarlanmıştır: Lignin Türevi Yarı Aromatik Biyobaz Polimer

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.

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

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Gyroid Nickel Nanostructures from Diblock Copolymer Supramolecules

Buradaki iki bloklu kopolimer Supramolecules ikinci Gyroid Nikel Nanoyapılar

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

Kimya

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

Phosphopeptides Gelişmiş Zenginleştirme için Makrogözenekli Polimer Monoliths üzerinde yüksek Gözenekli Koordinasyon Polymer Coatings Hazırlanması

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

Karma Polimer / Fulleren Nanopartikül photosensitizers Şefliği ile Fotodinamik Tedavi

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

Küçük açılı Nötron Saçılma tarafından Thermo-geri dönüşümlü Blok Kopolimer ve Karakterizasyonu Tek duvarlı Karbon Nanotüpler işlevselleştirilmesi

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

Termo-tersinir Çapraz bağlı Lastik Via Diels-Alder Kimya hazırlanması ve Özellikleri

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

Lazer güdümlü Ultrafast Moleküler Rotasyon Doğrudan Görüntüleme

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

Mikrosıvısal kuru-iplik ve rejenere ipek Fibroin lifleri karakterizasyonu

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

Elektrokimyasal empedans spektroskopisi elektrokimyasal oranı sürekli tahmini için bir araç olarak

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

Zaman karar vermek Photophysical karakterizasyonu üçlüsü-hasat organik bileşikler bir oksijensiz ortamı kullanarak bir ICCD kamera

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