Uporabne spojine in materiali na osnovi lignina in barvil invazivnih tujerodnih rastlin

doktorska disertacija

Monika Horvat (Author), Jernej Iskra (Mentor), Urška Lavrenčič Štangar (Thesis defence commission member), Hrvoje Petković (Thesis defence commission member), Stojan Stavber (Thesis defence commission member)

Abstract

Vedno večja ozaveščenost o okoljski problematiki usmerja veliko pozornosti pridobivanju snovi iz naravnih obnovljivih virov. Lignocelulozna biomasa predstavlja glavni obnovljivi vir organskega ogljika na zemlji ter s tem naravni vir za pridobivanje kemikalij. V okviru doktorske disertacije smo raziskali možnosti valorizacije in nadgradnje najmanj izkoriščenih komponent rastlinske biomase invazivnih tujerodnih rastlin (ferulna kislina, lignin, sekundarni metaboliti). Raziskali smo oksidativno cepitev dvojne in enojne vezi C–C, ki je iz sintetičnega vidika izredno pomembna reakcija za razgradnjo kompleksnih molekul iz biomase. Z uporabo oksidanta H2O2 ter katalizatorja V2O5, smo razvili metodo za selektivno oksidativno cepitev dvojne C–C vezi. Metoda omogoča selektivno pretvorbo derivatov cimetove kisline do benzaldehidov, benzokinonov ali benzojskih kislin. Selektivnost reakcije je odvisna od izbire topila. Derivate p-hidroksicimetove kisline smo v DME selektivno pretvorili do ustreznih benzaldehidov ter v TFE do benzokinonov. Derivate cimetove kisline in stirene, ki na para mestu nimajo hidroksilne skupine pa smo v MeCN selektivno pretvorili do benzojskih kislin. Metoda je primerna tudi za selektivno pretvorbo ferulne kisline do vanilina (91 %) v prisotnosti 7 ekv. 30 % H2O2 ter 5 mol% katalizatorja V2O5. Oksidativna cepitev enojne C–C vezi pa igra pomembno vlogo pri pretvorbi lignina do platformnih kemikalij. Predhodno razvito metodo na osnovi H2O2/V2O5 smo razširili na različne vrste lignina. Uporabili smo komercialno dostopen lignin ter realne vzorce organosolv in kraft lignina japonskega dresnika, octovca in smreke. Zaradi raznolike strukture ligninskih vzorcev, ki smo jo določili z NMR spektroskopijo smo oksidativno razgradnjo študirali posebej na vseh treh tipih vzorcev. V DME smo uspešno pretvorili komercialni lignin ter kraft lignin smreke do vanilina (izkoristek: 9,9 % in 7,6 %), kraft lignin japonskega dresnika pa smo depolimerizirali do mešanice aromatskih produktov. IAPS so bogate z različnimi strukturnimi tipi naravnih barvil, ki smo jih izolirali z ekstrakcijo. Emodin, izoliran iz korenik japonskega dresnika smo kemijsko modificirali z uvedbo različnih funkcionalnih skupin z nitriranjem, sulfoniranjem in halogeniranjem. S kemijsko spremembo strukture emodina smo vplivali na njegove barvne, vezavne, protivirusne ter protibakterijske lastnosti. Emodine smo fotokemijsko okarakterizirali ter jih uporabili kot fotokatalizatorje v reakcijah reduktivne aktivacije aril halidov. Na knjižnici spojin emodina smo izvedli tudi študijo vpliva strukture na protivirusno aktivnost proti HCoV-NL63. Jodiran emodin E-3I in bromiran emodin E-2Br sta izkazala primerljivo protivirusno aktivnost kot Remdesivir, ki je že odobren za uporabo v nujnih primerih proti COVID-19. Derivate emodina smo uspešno vezali na tekstilni material (volno in poliamid), ki je izkazal protibakterijsko aktivnost proti bakterijam S. aureus. Rezultati kažejo, da se kljub vezavi spojin na tekstilni material ohrani njihova protibakterijska aktivnost. Emodin, ekstrakte iz IAPS ter lignin in PHA smo uspešno inkorporirali tudi v prevleke silanskega tipa, ki omogočajo pripravo barvnih ter transparentnih hidrofobnih premazov za steklo in les.

Keywords

invazivne tujerodne rastline;lignocelulozna biomasa;vodikov peroksid;oksidacija;zelena in trajnostna kemija;ferulna kislina;vanilin;naravna barvila;emodin;HCoV-NL63;prevleke;doktorske disertacije;

Data

Language:	Slovenian
Year of publishing:	2022
Typology:	2.08 - Doctoral Dissertation
Organization:	UL FKKT - Faculty of Chemistry and Chemical Technology
Publisher:	[M. Horvat]
UDC:	547.458.84(043.3)
COBISS:	117009923
Views:	126
Downloads:	73
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	Useful compounds and materials based on lignin and dyes of invasive alien plants
Secondary abstract:	The growing awareness of environmental issues and sustainable development is focused on obtaining materials from renewable sources. Lignocellulosic biomass represents the most important renewable source of organic carbon on earth, making it a natural source for the production of chemicals. In doctoral dissertation, we focused on the utilization of less utilized components of plant biomass from IAPS (lignin, ferulic acid, and secondary metabolites). We investigated the oxidative cleavage of double and single C–C bonds, which is an important reaction for decomposition of complex molecules from biomass, from a synthetic point of view. Using the oxidant H2O2 and the catalyst V2O5, we developed a method for selective oxidative cleavage of C–C double bonds. The method allows selective conversion of cinnamic acid derivatives into benzaldehydes, benzoquinones or benzoic acids. The selectivity of the reaction depends on the solvent chosen. Derivatives of p-hydroxycinnamic acid were selectively converted to the corresponding benzaldehydes in DME and to benzoquinones in TFE. Cinnamic acid and styrene derivatives, which do not have a hydroxyl group at the para site, were selectively converted to benzoic acids in MeCN. The method allows selective conversion of ferulic acid to vanillin (91 %) in the presence of 7 eq. of 30 % H2O2 and 5 mol% catalyst. Oxidative cleavage of single C-C bonds plays an important role in the conversion of lignin to platform chemicals. A previously developed method based on H2O2/V2O5 was extended to various types of lignin. We used commercial lignin and real samples of kraft and organosolv lignin from Japanese knotweed, Staghorn sumac, and spruce. Due to the different structures of the lignin samples as determined by NMR spectroscopy, oxidative degradation was studied separately on all three sample types. In DME, commercial lignin and kraft lignin of spruce were successfully converted to vanillin (yields: 9.9% and 7.6%). Kraft lignin from Japanese knotweed was successfully depolymerized to a mixture of aromatic products. IAPS are rich in various structural types of natural dyes, that have been isolated by extraction. Emodin isolated from Japanese knotweed was chemically modified by introducing various functional groups through nitration, sulfonation, and halogenation. Chemical modification of the emodin structure affected its color, binding, and antiviral and antibacterial properties. The emodin derivatives were photochemically characterized and used as photoredox catalysts for photoreduction of aryl halides. A Structure-Activity Relationship was performed with the emodin derivatives for antiviral activity against HCoV-NL63. Iodinated E-3I and brominated emodin E-2Br showed comparable antiviral activity as Remdesivir, which is already approved for use in emergency COVID-19 cases. Emodin derivatives were successfully bound to textile material (wool and polyamide). The functionalized textile material also showed antibacterial activity against S. aureus. Emodin, IAPS extracts, lignin and PHA were successfully incorporated into silane-type coatings, enabling the preparation of colored and transparent hydrophobic coatings for glass and wood.
Secondary keywords:	invasive alien plant species;hydrogen peroxide;oxidation;green and sustainable chemistry;biomass;lignin;ferulic acid;vanillin;natural dyes;emodin;HCoV-NL63;coatings;Lignin;Rastline;Disertacije;Invazivne tujerodne vrste;Univerzitetna in visokošolska dela;
Type (COBISS):	Doctoral dissertation
Study programme:	1000381
Embargo end date (OpenAIRE):	1970-01-01
Thesis comment:	Univ. v Ljubljani, Fak. za kemijo in kemijsko tehnologijo
Pages:	211 str.
ID:	15786508