Preparation of a biolubricant in a ionic liquid

Cilj ovog rada bio je istražiti najbolje uvjete za sintezu biomaziva izoamil oleata enzimatskom esterifikacijom izoamil alkohola i oleinske kiseline. Reakcija je provedena uz prisustvo Candida antarctica lipaze B. Reakcija je također testirana u inkubator miješalici u n-heksanu i dvije ionske kapljevine; 1-butil-3-metilimidazol heksafluorofosfatu ([BMIM] PF6) i 1-butil-3-metilimidazol tetrafluoroboratu ([BMIM] BF4) pri različitim temperaturama (30 °C, 40 °C, 50 °C, 60 °C). Koristeći n-heksan kao otapalo nakon 24 sata dobivena je konverzija oleinske kiseline od 95 %, dok je korištenjem ionskih kapljevina jednaka konverzija oleinske kiseline postignuta već nakon 60 minuta. Također, ustanovljeno je da u ovim slučajevima temperatura nema značajan utjecaj na konverziju. Daljnji eksperimenti provedeni su u ionskoj kapljevini 1-butil-3-metilimidazol heksafluorofosfatu ([BMIM] PF6) pri različitim temperaturama (30 °C, 40 °C, 50 °C) koristeći kotlasti reaktor s mikrovalovima. Ustanovljeno je da porastom temperature raste i konverzija oleinske kiseline. U svim slučajevima, količina proizvedenog izoamil oleata analizirana je plinskom kromatografijom. Rezultati su pokazali da se provođenjem reakcije u kotlastom reaktoru s mikrovalovima uz 1-butil-3-metilimidazol heksafluorofosfat ([BMIM] PF6) kao otapalo postiže najveća konverzija od 68 % u vremenu od 20 min pri 50 °C. Količina vode proizvedene tijekom reakcija esterfikacija određena je Karl Fischer titracijom te se u svim slučajevima konstantno povećavala što je i karakteristično za reakciju esterifikacije. U posljednjem dijelu eksperimenta testirana je aktivnost enzima u kotlastom reaktoru s mikrovalovima pri dvije različite temperature (40 °C, 50 °C). Rezultati su pokazali da aktivnost enzima pada s brojem ciklusa upotrebe te se također pri većoj temperaturi dobiva veća konverzija supstrata.The aim of this study was to investigate the best conditions for the synthesis of biolubricant, isoamyl oleate by enzymatic esterification of isoamyl alcohol and oleic acid. The reaction was catalyzed by Candida antarctica lipase B. The reaction was also tested on a laboratory shaker in n-hexan and two ionic liquids; 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM] PF6) and 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM] BF4) at different temperatures (30 °C, 40 °C, 50 °C, 60 °C). Using n-hexane as a solvent after 24 hours a conversion of oleic acid of 95 % was achieved while using ionic liquids the same conversion was achieved already after 60 min. Also, it was found that in these cases the temperature has no significant impact on oleic acid conversion. Further experiments were carried out in ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM] PF6) where the heating was carried out using microwawes. It was found that at higher temperature conversion is higher too. In all cases, the amount of produced isoamyl oleate was analyzed by gas chromatography. Results showed that using microwawe heating in combination with ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM] PF6) as solvent it is possible to get the highest conversion of 68 % after 20 min at 50 °C. The amount of water produced during esterification reactions was detected using Karl Fischer titrator and in all cases it was increasing which is characteristric for reaction of esterification. The reuse of enzyme was tested in the final step of experiment using microwawe heating at two different temperatures (40 °C, 50 °C). This experiment showed that the activity of enzyme decreases with numbers of use and also at higher temperature conversion is higher