EXPLORATION OF BIOMIMETIC CATALYSTS FOR GLUCOSE HYDROGENATION AND THE POTENTIAL OF ZINC OXIDE NANOPARTICLES AS ANTIOXIDANT AGENTS

• Main Author: Herdianto, Sabrina
• Format: Theses
• Language: Indonesia
• Subjects: Teknik kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/75969
• Institution: Institut Teknologi Bandung

<p align="justify">Glucose (C6H12O6) is an abundant organic compound in nature and is used to create building blocks and derivatives of various chemical products, one of which is sorbitol. However, the commercial production method of sorbitol using hydrogen gas and supported nickel catalysts is still expensive and environmentally unfavorable. An alternative method practiced in this research is biomimetic hydrogenation, which mimics the working mechanism of aldose reductase (AR) enzyme that reduces glucose with hydrogen donors such as NADPH and H+ at low temperature and pressure. The catalysts used are Ni-Fe tetrathiomolybdate [(NixFe1-x)MoS4] with x = ½ and ¾, greigite (Fe3S4), [(NipFe1-p)(CrqFe1-q)2S4] with p = ½ and q = ¼, (Ni½Zn½)(OOCH)2.2H2O, and Ni(MIII)2O(OOCH)6.3H2O with M ? Cr and Fe. The reaction is performed at pH 4.5–6.5 and atmospheric reflux conditions (80 - 105 ?) for 6 hours with hydrogen sources such as formic acid and triethylamine. The research results show that the highest conversion of glucose is 37% with the catalyst Ni(FeIII)2O(OOCH)6.3H2O, and after the addition of NaOH and distillation, the average glucose conversion is above 30% with all catalysts. Furthermore, the HPLC analysis results show the presence of fructose without the presence of sorbitol in the reaction solution, indicating a suspected isomerization reaction of glucose into fructose. Triethylamine and NaOH are utilized as base catalysts to catalyze the isomerization reaction. On the other hand, with the increasing prevalence of diabetes, apart from using sorbitol as a low glycemic index alternative sweetener, the development of antidiabetic and antioxidant agents is conducted, one of which is zinc oxide nanoparticles (ZnO). Propolis extract with methanol serves as an environmentally friendly solvent and contributes to the antidiabetic and antioxidant activities of the resulting nanoparticles. The results of the DPPH free radical scavenging assay indicate that the inhibitory abilities of Pro-ZnO NPs against ?-amylase and ?- glucosidase reach 69.52% and 73.78%, respectively, while its antioxidant capacity reaches 70.76%.