Procesi v nekonvencionalnih superkritičnih fluidih

diplomsko delo univerzitetnega študijskega programa I. stopnje

Tjaša Petrovič (Author), Željko Knez (Mentor), Mojca Škerget (Co-mentor)

Abstract

Za določanje vsebnosti vanilina v zmletih strokih vanilije smo uporabili tri vrste ekstrakcij, in sicer: ekstrakcijo s superkritičnima fluidoma argonom in CO2 pri temperaturah 25 °C, 40 °C in 60 °C ter tlakih 150 bar in 300 bar, ekstrakcijo po Soxhletu in konvencionalno ekstrakcijo, obe s topiloma metanol in etanol. Rezultati kažejo, da dobimo z ekstrakcijo po Soxhletu in konvencionalno ekstakcijo zelo velike izkoristke, tudi nad 50 %, in da so le-ti večji pri topilu metanol, kar pomeni, da je ta primernejše topilo od etanola. Drugače kažejo rezultati pri ekstrakciji s superkritičnimi fluidi, kjer so izkoristki zelo nizki, in sicer okrog 1 % pri argonu in 5 % pri CO2. Dobljene ekstrakte smo raztopili v metanolu in jim merili absorbance pri valovnih dolžinah 228,5 nm (vanilin) in 270 nm (OEV). UV analize so pokazale, da je vsebnost vanilina v ekstraktih, pridobljenih z ekstrakcijo s superkritičnimi fluidi, višja kot v ekstraktih, pridobljenih z ekstrakcijo po Soxhletu ali s konvencionalno ekstrakcijo. Iz tega lahko sklepamo, da so superkritični fluidi veliko bolj selektivna topila. Določali smo topnost vanilina in orto etilvanilina v argonu pri temperaturah 40 °C, 60 °C in 80 °C ter tlakih v območju do 500 bar ter rezultate primerjali s topnostjo vanilina in OEV v CO2. Ugotovili smo, da je pri nižjih temperaturah in tlakih do približno 200 bar topnost višja v argonu. Z dodatnim višanjem tlaka topnost narašča počasneje.

Keywords

vanilija;vanilin;orto etilvanilin;superkritična ekstrakcija;konvencionalna ekstrakcija;ekstrakcija po Soxhletu;topnost;UV analiza;

Data

Language:	Slovenian
Year of publishing:	2013
Typology:	2.11 - Undergraduate Thesis
Organization:	UM FKKT - Faculty of Chemistry and Chemical Engineering
Publisher:	[T. Petrovič]
UDC:	66.040:547.576(043.2)
COBISS:	17477654
Views:	2013
Downloads:	254
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary title:	PROCESSES IN NON - CONVENTIONAL SUPERCRITICAL FLUIDS
Secondary abstract:	Three types of extraction were used to determine the content of vanillines in milled vanilla pods: extraction with supercritical fluids; argon and CO2 at temperatures of 25 °C, 40 °C and 60 °C and at pressures of 150 bar and 300 bar, Soxhlet extraction and conventional extraction, both with solvents methanol and ethanol. Very high yields appear in the case of Soxhlet and also conventional extraction, even higher than 50 %, furtheremore they higher when using methanol as a solvent. Therefore methanol resulted as a more adequate solvent than ethanol. Yields are low in case of extraction with supercritical fluids approximately 1 % with argon and 5 % with CO2. Obtained extracts were dissolved in methanol and absorbance was measured at a wavelength of 228,5 nm (vanillin) and at a wavelenght of 270 nm (OEV). UV analysis show higher content of vanillin in extracts, obtained by extraction with supercritical fluids (supercritical extraction), than in those obtained with the Soxhlet extraction or conventional extraction. Therefore it can be concluded that supercritical fluids are way more selective than conventional solvents. Solubility of vanillin and ortho ethylvanillin in argone at temperatures of 40 °C, 60 °C and 80 °C and at pressures up to 500 bar was also determined. Results were compared to solubility in of OEV and CO2. It was clearly observed that solubility is higher in argon under lower temperatures and pressures up to about 200 bar. With additional increase of pressure only a slight impact on solubility is noted.
Secondary keywords:	vanilla;vanillin;orto ethylvanillin;supercritical extraction;conventional extraction;soxhlet extraction;solubility;UV anaysis;
URN:	URN:SI:UM:
Type (COBISS):	Bachelor thesis/paper
Thesis comment:	Univ. v Mariboru, Fak. za kemijo in kemijsko tehnologijo
Pages:	XI, 50 f.
ID:	8726660