MODIFICATION OF SILICA BIS-APTES WITH MYRISTIC ACID AND FATTY ACID B100 HYDROLYSIS PRODUCT

• Main Author: Syafira, Abyaska
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/62818
• Institution: Institut Teknologi Bandung

Silica is widely used as an adsorbent because it is easy to use for certain adsorbates. In this study, the reaction between amine-modified silica and fatty acids was carried out to reduce the polarity of the silica. The synthesized products are expected to optimize silica’s affinity the adsorption of nonpolar organic compounds. Fatty acids were obtained by B100 hydrolysis using NaOH at a reflux temperature of 100°C for 2 hours and acidification using H2SO4. Confirmation of the formation of fatty acids from B100 was carried out by analysis of the 1H- NMR spectrum, which showed the loss of the absorption peak at 3.6 ppm which indicated that the methoxy group had been released. Amino-modified silica was obtained from the reaction of Bis[3-(Aminopropyltriethoxysilane)] with toluene as a solvent and an ammonia catalyst in a volume ratio of 80: 15: 5 which was stirred for 24 hours. Bis-APTES modified silica was then reacted with fatty acid product from B100 hydrolysis using toluene as a solvent and coupling reagents N,N'-Dicyclohexylcarbodiimide (DCC) and 4-Dimethylaminopyridine (DMAP). For comparison, myristic acid was also reacted with Bis-APTES modified silica using the same method. The products of each stage were characterized by FTIR. By comparing the FTIR spectrum of silica fatty amide before and after modification, it can be observed that there was an adsorption band decrease at 1134 cm-1 which indicated the weakening of the Si- O-Si strain and at 1708 cm-1 which indicated the weakening of the C=O strain. The IR bands of fatty acids are difficult to read on FTIR spectra because of their small amount compared to the much larger silica particle size. Morphological characterization by TEM showed aggregated and irregular modified silica. The synthesized amide myristate modified silica shows the ability to adsorb caffeine analytes. The remaining caffeine were measured using HPLC and the results showed that the concentration was reduced from 100 ppm to 95,7705 ppm while there is no reduction in caffein concentration in contact with silica modified Bis- APTES. Therefore, the attachment of fatty acids to amine-modified silica has the potential to be used as an adsorbent for nonpolar compounds.