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181	Polymer Chemistry & Bio-based Materials	ABS-108
VALORISATION OF BANANA STUMPS WITH POLYOL AND CHITOSAN AS BIOPLASTIC FEEDSTOCK Rafkita Shelly1, Ayu Silvia Fitri1, M.Hasbi Ar-Raihan1, Oktaviani Wulandari1 , S.A. Ajipratama1, Nila Tanyela Berghuis1 Universitas Pertamina Abstract Banana stumps, which are plentiful yet still underutilized, are one of the waste products of the banana harvesting process. Recent research indicates that banana stumps contain up to 76 percent starch. To address environmental issues brought on by the use of disposable plastics, we used starch from banana stumps as bioplastics feedstock. To enhance the performance of bioplastics, experiments with the addition of glycerol, sorbitol, and chitosan were conducted. FTIR spectra of the two bioplastic films indicate that additives do not alter the functional groups of bioplastics because they give equal absorption areas with just varying intensities. The result of the thermogravimetric analysis showed glycerol bioplastics disintegrated more quickly (231.85oC) than sorbitol bioplastics (278.75oC). The water absorption test reveals that glycerol bioplastics are more water-resistant than sorbitol bioplastics. According to the results of the biodegradation test, sorbitol bioplastics break down more quickly than glycerol bioplastics. The tensile strength test of sorbitol-based bioplastics yielded a value of 2.233 N/m2, which is greater than the glycerol-based bioplastics^ value of 1.83 N/m2. These results show the banana stump^s potential as a feedstock for the manufacturing of bioplastics. Keywords: Bio-based Plastics, Biodegradable Plastics, Banana Stump, Starch, Plasticizer Share Link | Plain Format | Corresponding Author (Nila Tanyela Berghuis)

182	Polymer Chemistry & Bio-based Materials	ABS-117
Ecofriendly coaster or packaging candidate from lemongrass essential oil waste Richard Reynchak Tanduwuya, Arliani Sukma, Paramita Jaya Ratri*, Azis Adharis, Syifa Asatyas Department of Chemistry, Faculty of Science and Computer Universitas Pertamina Abstract Lemongrass plants is spread all over the country, Indonesia. Lemongrass is one of the commodities that has the potential to be developed for both as a food ingredient and as an industrial raw material. As a food ingredient, lemongrass is widely used as a spice in some processed foods. Supporting green chemistry campaign, the lemongrass waste from steam processed was transform into ecofriendly coaster or packaging which varies in composition of chitosan, glycerol, tapioca, and recycled paper pulp. In this study, mechanical properties and thermal degradability of the eco-friendly coaster or packaging candidate are studied by Universal Testing Machine and Thermogravimetry Analysis. Keywords: lemongrass waste, ecofriendly packaging, ecofriendly coaster, Share Link | Plain Format | Corresponding Author (Paramita Jaya Ratri)

183	Polymer Chemistry & Bio-based Materials	ABS-127
Synthesis of Polyurethane Foams from Hydroxylated and Aminated Alkali Lignin Azis Adharis, Ph.D., Dr. Nila Tanyela Berghuis, M.Si., Athirah Nursalsabila, S.Si. Department of Chemistry, Universitas Pertamina Abstract Nowadays, polyurethane foams become a demanded product by industries because of its application broadness. Polyurethane foams are synthesized by using polyols and isocyanates, but the commonly used polyols are derived from petrochemical products. Due to high demand and price of oils, it is necessary to find alternative sources of polyol, for instance based on natural and renewable products. In this research, polyurethane foams have been successfully synthesized by using alkali lignin as the polyols. Structure modification of standard alkali lignin was done through hydroxylation and amination reaction. Characterizations of the polyols and foam samples that includes determination of hydroxyl content, ninhydrin test, FTIR spectroscopy, and SEM. Based on the analyzed results, the amount of hydrogen peroxide affects the hydroxyl contents during hydroxylation reaction, yet it gives no effect on the amination reaction. SEM images show that polyurethane foams have a porous surface morphology. Keywords: Polyurethane foam- Alkali lignin- Hydroxylation- Amination. Share Link | Plain Format | Corresponding Author (Azis Adharis)

184	Polymer Chemistry & Bio-based Materials	ABS-167
SODIUM BICARBONATE ACTIVATED CARBON FROM EMPTY FRUIT BUNCHES Nelly Wahyuni, Imelda H. Silalahi, and Ismadi Department of Chemistry, University of Tanjungpura Abstract The use of carbon in the industriousness moment is veritably important. Activation can amplify carbon absorption. This report aims to determine how various activator sodium bicarbonate concentrations, temperatures, and activation times directly affect iodine numbers of carbon from the empty fruit bunch. Carbon was calcined at 500 C for 1 hour, then activated by sodium bicarbonate. In addition to the iodine number analysis, activated carbon was also characterized using FTIR to study functional groups, as well as gas sorption analysis to determine surface area and diameter pore. The results show that the system activation conditions were obtained at 600 C for 1 hour with 4% sodium bicarbonate concentration. The properties of the produced sorbent include an iodine number of 430.4 mg/g, water content of 12.31%, an ash content of 5.79%, and density of 1.26 g/mL, and specific surface area of 362.37 m2/g. In general, a functional group overview does not alter the infrared spectrum of carbon before or after activation. The results confirmed that the ash and activated carbon water content complied with SNI 063730199 standards, and the pores were micron-sized. Keywords: Activated carbon, Activator, Empty fruit bunches, Sodium bicarbonate Share Link | Plain Format | Corresponding Author (Nelly Wahyuni)

185	Polymer Chemistry & Bio-based Materials	ABS-185
Effect of the Monomer Chain Length on the Structure and Properties of Polyamide-based Thermoplastic Elastomers Yeyen Nurhamiyah (a)(b*), Biqiong Chen(a) (a)School of Mechanical and Aerospace Engineering, Queen^s University Belfast, Stranmillis Road, Belfast, United Kingdom (b)Research Center for Biomass and Biproducts, National Research and Innovation Agency (BRIN), Jl. Raya Bogor KM. 46 Cibinong, Bogor, Indonesia *email: yeye001[at]brin.go.id Abstract The monomer chain length and the ratio of amide linkages to the methylene, among others, contribute to the properties of polyamides. A series of fatty based polyamides including PA36,4, PA4,36, PA36,9 and PA9,36 were synthesised by melt polycondensation and the effects of monomer chain length on the properties were studied. Apart from PA36,4, the other three polyamides exhibited melting temperatures of 83.6 oC - 94.7 oC, glass transition temperatures of ~ 17 oC, high stretchability (up to 1450%) while maintaining high strength (up to 24 MPa), excellent impact, flexural, and tear behaviour, as well as superhydrophobicity. The length of monomer chain in the repeating unit influences the ratio of rigid amide linkage and thus the properties of the resulting polyamide. Keywords: polyamide, elastomer, chain-length, fatty acid Share Link | Plain Format | Corresponding Author (Yeyen Nurhamiyah)

186	Polymer Chemistry & Bio-based Materials	ABS-191
Optimization of Addition DMC (Dimethyl Carbonate) in PP (Polypropylene) Plastic Waste Pyrolysis Oil Lela Mukmilah Yuningsih, Dikdik Mulyadi, Ecky Trisnawati Universitas Muhammadiyah Sukabumi Abstract PP (Polypropylene) plastic waste pyrolysis oil can be used as fuel oil through the pyrolysis process, but there is a need for efforts to improve the quality of the oil, one of which is with oxygenate additives, namely Dimethyl Carbonate (DMC). DMC has a high oxygen content of 53%/weight and is a green chemistry additive. The focus of this research is to determine the optimum concentration of DMC which can improve the quality of PP waste pyrolysis oil. The method used is pyrolysis of PP waste at a temperature of 80-90oC and then purification by distillation, then blended with DMC 5% v / v (PPD5), 10% v / v (PPD10), and 13% v / v (PPD13) by tracing several parameters such as viscosity 40oC, density 15oC, calorific value, and octane value. The results obtained from PP100 pyrolysis oil (after purification) contain more carbon range C5-C 12 70.64% which is a component of the gasoline hydrocarbon range. The optimum concentration to improve the quality of PP waste pyrolysis oil is found in PPD13 samples which is based on its ability to increase the octane value of RON from 89.3 (PP100) to 90.8 and a larger anti-knocking index compared to other DMC concentrations, which is 89.9 Keywords: Pyrolysis, Aditive, Polypropylene, Dimethyl Carbonate, Octane Number Share Link | Plain Format | Corresponding Author (Lela Mukmilah Yuningsih)

187	Polymer Chemistry & Bio-based Materials	ABS-204
Characterization of Graphite from Palm Oil Mesocarp Fiber Waste Using Nickel (II) Nitrate Catalyst in Graphitization Process Rinette Visca (a*), Cynthia Veronika Tarigan (a), Asep Handaya Saputra (a) (a) Chemical Engineering Department, University of Indonesia Margonda Raya Street, Depok , Indonesia *rinette.visca[at]ui.ac.id Abstract Recently graphites, used in industrial processes are mainly synthetic graphite. The problem is that the conventional graphitization process consumes a lot of energy, and the carbon precursors used are typically non-renewable. The purpose of this study is to form synthetic graphite from carbon precursor from palm oil mesocarp fiber waste. Lignocellulosic biomass carbon precursors, such as oil palm mesocarp fibers waste, tend to form ungraphitizable carbon when carbonized. Nevertheless the use of the catalytic graphitization method create graphitization of ungraphitizable carbon. Parameter considered in this study is the degree of graphitization, which shows how much of the material is structured in graphitic order. One of the factors that affect the degree of graphitization is the type of the catalyst used in the process. In this research, the catalyst variations used are nickel (II) nitrate and iron (III) nitrate with graphitization temperature of 900oC and equal catalyst loading of 3 mmol metal per gram carbon sample. The result of graphitization of palm oil mesocarp fibre waste using nickel (II) nitrate catalyst, did not show the ordered structures of a graphitic carbon, but the graphitization using iron (III) nitrate shows that the resulting product has a graphitic structure with a degree of graphitization of 73,4%, which is significantly better than using nickel (II) nitrate. Keywords: synthetic graphite, catalytic graphitization, oil palm mesocarp fibre, nickel (II) nitrate, iron (III) nitrate Share Link | Plain Format | Corresponding Author (RINETTE VISCA)

188	Polymer Chemistry & Bio-based Materials	ABS-217
EFFECT OF GLYCEROL MONOSTEARATE (GMS) AS A COMPATIBILIZER COMPONENT IN POLYMER BLEND HIGH DENSITY POLYETHYLENE (PE-PS) RESIN COMPOSITE Istikamah Subuki (a*), Nur Azrini Ramlee (a), Ahmad Rafizan Mohamad Daud (a), Muhammad Hussain Ismail (b), Norazlen Rasid (a) a) School of Chemical Engineering, College of Engineering, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia *istikamah[at]uitm.edu.my b) School of Mechanical Engineering, College of Engineering, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia Abstract High percentage of palm stearin (PS) into a long molecular weight polymer (PE) resin may results in instability phenomena that is not sufficient to provide a good flowability of the feedstock for injection moulding. Thus, the objective of this report is to study the effect of addition of glycerol monostearate (GMS) as a compatibilizer with high PS content of 40 wt.%. The composite was characterised through torque analysis, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) analysis, rheology analysis, hot pressing and compaction and also mechanical characterization. It is found that, as GMS increase, both melting point and degradation temperature decrease. From the rheological properties, it shows that presence of GMS in the PS/PE can efficiently improve flowability and shows good moulded specimen. The tensile analysis shows high mechanical properties in PS/PE when GMS is added. Thus, GMS is a suitable plasticizer for PS/PE resin. Keywords: Palm Stearin, Glycerol Monostearate, Rheology, Flowability Share Link | Plain Format | Corresponding Author (Istikamah Subuki)

189	Polymer Chemistry & Bio-based Materials	ABS-223
Effect of crosslinking on the properties and performance of membrane formulated from quaternized chitosan Norin Zamiah Kassim Shaari (a*), Muhammad Afnan Naim Kamarulzaman (a), Nur Syazwanie Izzati Chik (a) (a) School of Chemical Engineering, College of Engineering, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia * norinzamiah[at]uitm.edu.my Abstract Surface waters may carry heavy metals over long distances, and their chemical composition changes as they move around according to geographic factors. Among separation methods, adsorption is a common method for removing heavy metals from water due to its low cost, high availability, and being environmentally friendly. Chitosan is widely used as an adsorbent for heavy metals due to the presence of amino and hydroxyl groups. In this research, chitosan is modified through the quaternization process to enhance its adsorption capability. Hexadecyltrimethylammonium bromide (TMAB) was used as the quaternizing agent. The quaternized chitosan was then blended with polyvinyl alcohol and polysulfone to produce a membrane, which was then crosslinked with tetraetylorthosilicate. In the production of quaternized chitosan, a fixed loading of quaternizing agent was used but various concentrations of tetraethylorthosilicate as cross-linker were incorporated in the membrane formulation. The formulated membranes were then characterized through Fourier Transform Infrared (FTIR) Analysis, Field Emission Scanning Electron Microscope (FESEM), and zeta potential. The performances were tested through permeation of water and anti-fouling analysis. Results show that membrane M4 with 0.4wt% TEOS had the best characteristic, particularly on the surface charge and surface morphology with the good antifouling property. The formulated membranes have the potential to be used in water treatment for the heavy metal removal process. Keywords: Hexadecyltrimethylammonium bromide, quaternized chitosan, membrane, tetraethylorthosilicate Share Link | Plain Format | Corresponding Author (Norin Zamiah Kassim Shaari)

190	Renewable Energy & Energy Storage	ABS-12
ELECTRICAL ENERGY PRODUCTION WITH MICROBIAL FUEL CELL (MFC) TECHNOLOGY ON GRACILARIA VERRUCOSA SUBSTRATE 1.Aisyah Rusdin, 2.Ahyar Ahmad,3.Abdul Karim, 4.Firnanelty 1. Department of Chemistry, Institut Sains dan Kesehatan Bone, Jl. Dr.Wahidin Sudirohusodo, Bone, Indonesia 2,3. Department of Chemistry, Universitas Hasanuddin, Jl. Perintis Kemerdekaan Km. 10, Makassar, Indonesia. 4. Department of Chemistry, Universitas Islam Negeri Alauddin Makassar, Jl. H.M. Yasin Limpo, Makassar, Indonesia Abstract Microbial Fuel Cell (MFC) is a renewable technology based on electrochemistry that has the ability to convert chemical energy into electrical energy through microbial metabolic processes. This study aims to determine the effect of adding an electrolyte solution to the production of electricity generated using the substrate Gracilaria verrucosa and the microbe Saccharomyces cerevisie. The method used in this study uses a double chamber consisting of anode and cathode chambers connected through a proton exchange membrane (PEM) in the form of Nafion 117. The results showed that the addition of 0.2 M KMnO4 electrolyte solution produced current, voltage and power density respectively of 0.74 mA- 580 mV and 2187 mW/cm2 higher than the addition of 0.2 M K3Fe(CN)6 electrolyte solution resulted in a current, voltage and power density of 0.69 mA, respectively- 450 mV and 1582.16 mW/cm2. The MFC system using Gracilaria verrucosa as a substrate has the potential to generate electrical energy. Keywords: Microbial Fuel Cell (MFC), Electrical energy, Gracilaria verrucosa, Saccharomyces cerevisiae Share Link | Plain Format | Corresponding Author (Aisyah Rusdin)

191	Renewable Energy & Energy Storage	ABS-22
OPTIMIZATION AND QUALITY TESTING OF BRIQUETTE FROM MIXED VEGETABLE WASTE AND BONE WASTE Permata Maratussolihah(a*), Dewi Yulina Nur Soleha(a), Riska Riyanni(b), Widya Rospita(b), Mita Nurhayati(a,c) a) Study Program of Chemisrty, Universitas Pendidikan Indonesia *permatamaratussolihah[at]gmail.com b) Study Program of Chemistry Education, Universitas Pendidikan Indonesia c) Department of Advanced Science and Technology Convergence, Kyungpook National University, Sangju-si, Gyeongsangbuk-do, South Korea Abstract Briquettes are one of the alternative fuels that at the same time can be one solution in overcoming waste. In this study, the manufacture of bone waste briquettes and briquettes mixed with vegetable waste and bone waste as a solution to deal with domestic waste problems. The quality of briquettes is evaluated by comparing the length of initial ignition and the duration of briquettes made with coconut shell briquettes that have been widely sold in the market. The initial ignition time of vegetable waste and bone waste mixture briquettes is 1.49 minutes better when compared to bone-based briquettes. The timing showed results that did not differ significantly from the initial length of time on coconut shell-based briquettes. The 139.44-minute briquette mixture of vegetable waste and bone waste showed better effectiveness than coconut shells on the market. Keywords: Mixed Coconut Shell Briquettes, Mixed Briquettes, Bone Briquettes Share Link | Plain Format | Corresponding Author (Permata Maratussolihah)

192	Renewable Energy & Energy Storage	ABS-39
CHARACTERIZATION ON THE INTERACTION EFFECT OF BIO-OIL AND BIO-CHAR FROM SAGO DREGS FOR BIO-COKE APPLICATION AS AN ALTERNATIVE FUEL M Jahiding (1*), Mashuni Mashuni (2), Erzam S Hasan (1), Elfina L Lukman (1) and Yuke Milen (1) (1) Department of Physics, Halu Oleo University, Kendari, 93132, Indonesia (2) Department of Chemistry, Halu Oleo University, Kendari, 93132, Indonesia Abstract Sago dregs (SG) are the by-product of sago stems which contains cellulose components and has the potential as a biomass fuel source. Thus, this condition encourages the conversion of SG biomass waste into bio-coke as an alternative solid fuel by interacting with the bio-oil resulting from the pyrolysis of SG biomass. This study aims to determine the effect of variations in the alloy between bio-oil and bio-char SG as raw material for making bio-coke with bio-oil compositions of 10, 20, 30, 40 and 50% (w/v) using the pyrolysis method at a temperature of 500 to 600 \(^o\) C. The characterization results showed that the bio-coke content of the bio-oil alloy had a moisture content of \(2.99 \pm 0.9% \) , volatile matter of \(38.45\pm 6%\), ash content of \(13.91 \pm 0.6%\), and fixed carbon of \(44.65 \pm 6.4%\) . The calorific value of bio-coke increases with the composition of bio-oil, with a maximum calorific value of 13,565.854 kcal/kg. Thus, bio-oil interacting with SG bio-coke is a potential strategy for waste biomass management in alternative fuel applications. Keywords: bio-char, bio-coke, bio-oil, fuel, sago dregs Share Link | Plain Format | Corresponding Author (M Jahiding)

193	Renewable Energy & Energy Storage	ABS-123
TiO2 doped-SiO2 Photoanodes for Enhancing Power conversion efficiency in Dye-Sensitized Solar Cells Risa Rahmawati Sunarya (a), Rahmat Hidayat (b), and Veinardi Suendo (c)* (a) Chemistry Education Department UIN Sunan Gunung Djati Bandung (b) Physics Department Institut Teknologi Bandung (c) Chemistry Department Institut Teknologi Bandung *E-mail:vsuendo[at]chem.itb.ac.id Abstract TiO2 mesoporous nanoparticle films still used as photoanodes for good efficiency dye-sensitized solar cells (DSSC). Although TiO2 has good power conversion efficiency, the electron transport rate is known to be low due to low electron mobility. However, to improve the ability of photanodes to harvest photons some recent research results use a mixture of mesoporous oxide materials. In this research, we used SiO2 microbeads as a mixture of TiO2 with SiO2 weight composition of 0, 5, 10, 15, 20% was done. The TiO2-SiO2 photoanodes film was then coupled with the graphite/rGO-PANI film counter electrode to applied as DSSC. The results of DSSC cell performance with solar simulators showed a significant increase in Jsc and efficiency, from 6.52 to 8.11 mA/cm2 and 2.06 to 2.81% with 10% SiO2, respectively. While TiO2-SiO2 photoanodes, the presence of SiO2 microbeads with larger particle size than TiO2 can scatter light that comes into the photoanode better than the TiO2 nanoparticles, thus they produce more excited electrons that increase the flux of injected electrons into the external circuit. SiO2 helps to create new catalytic active site due to interaction between TiO2 and SiO2. SiO2 as the carrier of TiO2 and helps to obtain a large surface area as well as suitable porous structure. Keywords: TiO2-SiO2 photoanode, semiconductor materials, dye sensitized solar cell (DSSC) Share Link | Plain Format | Corresponding Author (Risa Rahmawati Sunarya)

194	Renewable Energy & Energy Storage	ABS-180
Effect of ethylene glycol in catalyst ink for fabrication of Pt/C electrode for polymer electrolyte membrane fuel cell Abdul Rohman Supandi*, Eka Sulistiawati, Muzamil Khatri, Hiroshi Fukunaga** Department of Chemistry and Materials, Faculty of Textile Science and Technology, Shinshu University Abstract The performance of polymer electrolyte fuel cells (PEFCs) is largely governed by the catalyst layer in membrane electrode assembly (MEA). The catalyst layer is prepared by the decal transfer method, and non-uniform microstructure is an issue for smooth surface of catalyst-coated membrane due to crack formation. In this study, we demonstrated the effect of ethylene glycol ratio in the catalyst ink on the microstructure of the electrode, to produce a smooth surface of the catalyst electrode layer having high performance in the single-cell evaluation test. The use of ethylene glycol prevented cracks in the catalyst layer most likely due to its adhesivity to the substrate and the controlled drying process. An optimum volume of ethylene glycol in the mixture of solvents was found to have a less crack in the catalyst layer and to have the lowest overpotential at all current densities during the I-V measurement. To investigate the effect of ethylene glycol on the microstructure of the catalyst layer and its performance as MEA layer, the microstructures of catalyst layers were observed by a digital microscope and scanning electron microscopy, and electrochemical measurements, such as impedance spectroscopy as well as electrochemical surface area were carried out. Keywords: Polymer electrolyte fuel-cell- Decal transfer- Pt/C catalyst- Ethylene glycol- Catalyst ink Share Link | Plain Format | Corresponding Author (Abdul Rohman Supandi)

195	Renewable Energy & Energy Storage	ABS-201
Determining the Optimum Condition on Synthesis Epoxidized TMPester and Studied the Effect of Acid Catalyst to Oxirane Ring Formed Ferra Naidir (a*), Robiah Yunus (b), Irmawati Ramli (c), Rinette Visca (a) a) Fakultas Teknologi Industri, Universitas Jayabaya, Jl. Raya Bogor Km 28.8 Cimanggis, Jakarta Timur, Indonesia *fnaidir.fn[at]gmail.com b) Fakulti Kejuruteraan, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Darul Ehsan, Malaysia c) Fakulti Sains, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Darul Ehsan, Malaysia Abstract In-situ epoxidation was used to produce epoxidazed Trimethylolpropane ester (TMP ester) to eliminate the fatty acid double bonds in palm oil-based TMP ester. Those TMP esters were used as the starting material in the epoxidation reaction to synthesize epoxidized TMP esters. The aim of reaction is increasing the oxidative stability on TMP ester as Bio-Lubricant. The epoxidation was conducted with peracetic acid formed in-situ from the reaction of glacial acetic acid with concentrated hydrogen peroxide (H_2O_2) and an amount of a homogeneous acid catalyst namely sulfuric acid (H_2SO_4) with heptane as inert solvent. In this work starts with determining the optimum reaction condition to produce epoxidized TMP ester by analyzing Iodine Value and Percentage of Oxirane Oxygen. Then observing the effect of sulfuric acid as catalyst on the ethylenic unsaturation of the TMP ester where were used on reaction of epoxidation TMP ester. Caused, increasing the catalyst concentration usually results in a higher percentage of oxirane oxygen in a shorter period. As for various concentrations used namely, 1%, 2%, 3%, 4%, and 5%, of sulfuric acid. Finally, the optimum oxirane product was achieved at 2% concentration of the catalyst H_2SO_4, with the percentage of oxirane oxygen being 3.85% against a maximum of 4.02% oxirane oxygen that is potentially attainable if 96% of the ethylenic unsaturation in TMP esters is converted to oxirane oxygen. Keywords: In-situ epoxidation, Palm oil-based TMP ester, epoxidized TMP ester, Sulphuric Acid, Iodine Value, Percentage of Oxirane Oxygen Share Link | Plain Format | Corresponding Author (Ferra Naidir)

196	Renewable Energy & Energy Storage	ABS-218
Preparation and cell performance of Pt nanosheet catalyst layer for polymer electrolyte fuel cell Hiroshi Fukunaga (a*) Department of Chemistry and Materials, Faculty of Textile Science and Technology, Shinshu University * fuku[at]shinshu-u.ac.jp Abstract Polymer electrolyte fuel cell (PEFC) is beginning to be used in practical applications such as fuel cell vehicles and residential cogeneration system. Its low operating temperature is suitable for rapid start up and shut down but supresses the reaction rate. Typically, carbon supported Pt (Pt/C) is used to enhance the oxygen reduction reaction at the cathode. However, since Pt is expensive and scarce, low Pt catalysts have been explored by many researchers. In addition, catalyst durability is beginning to be more of an issue since the use of PEFC in heavy-duty vehicle requires operation at high temperature. In this study, we focused on Pt-based nanosheet (Pt-ns) which is reported to have high mass activity and durability due to its flat structure consisting of few atomic layers. We developed two types of Pt-ns cathode, one is carbon supported Ru-core Pt-shell nanosheet catalyst (Ru@Pt-ns/C), originally developed by Takimoto and Sugimoto, and the other is non supported Pt nanosheet, developed by Takenaka et al. First, catalyst layer of Ru@Pt-ns/C was prepared by performing Cu underpotential deposition (UPD) and surface-limited redox replacement (SLRR) directly to the catalyst layer of Ru-ns/C, and it showed high fuel cell performance compared to the conventional electrode using Pt/C. Second, carbon-free ionomer-free Pt cathode was prepared by spray method and showed higher durability than Pt/C. Keywords: PEM fuel cell, Pt nanosheet, Core-shell catalyst, Cu-UPD, Cathode, MEA Share Link | Plain Format | Corresponding Author (Hiroshi Fukunaga)

197	Renewable Energy & Energy Storage	ABS-229
ELECTRON PROBABILITY (P0) AT LiFePO4 /C AND LiFe0,99GD0.01PO4/C CATHODES WITH DIFFERENT COATING MATERIALS A. Suprabawati, Istiqomah, H. Nofiati, N.F. Maulida, S.N.Azizah UNJANI Abstract ABSTRACT In this study, a mathematical calculation of the probability of the electron path (P0) in the cathode battery component to the anode was carried out. In this study, a mathematical calculation of the probability of the electron path (P0) on the cathode to the anode battery component was carried out. The electron path is formed through various interfaces between the cathode and the CEI electrolyte (Carbon electrolyte interphase). LFP lithium ion cathode material without LiFePO4 doped and LiFe0.99Gd0.01PO4 doped was synthesized by solid state method with carbon coating. Various coating materials, namely carbon (C), graphite (C6) and activated carbon (C+). The electron path probability (P0) describes the number of electrons from the anode that reaches the carbon (C) surface first as a coating which is proportional to the value of the tunneling current (Itl). In batteries the electron (e-) path is important to study because it balances lithium ions (Li+) which both move in opposite directions in the electrochemical reaction of the battery. The movement of electrons which is a wave function occurs in various contact areas of the electrolytic cathode and anode electrodes. This contact area consists of region I of the surface of the LiFePO4/C electrode with the outermost being carbon (C), region II of the interface (interphase) on the inner CEI (Carbon electrolyte interphase) layer, region III of the liquid solvent LiPF6. From the results of the study, the P0 value at the LiFePO4 /C cathode of palm shell activated carbon was P0 = 2.6238, graphite activated carbon (C6) P0 = 3.2169 P0 value at the LiFe0.99Gd0.01PO4/C cathode on carbon black ( C) is equal to P0=3,2037 . The electron path probability value (P0) which indicates good electron movement is in the range > 1. Keywords: electron path probability (P0), LiFePO4 cathode, LiFe0.99Gd0.01PO4/C cathode, CEI cathode (Carbon electroltye interphase) and coating material Share Link | Plain Format | Corresponding Author (anggi suprabawati)

198	Theoretical and Computational Chemistry	ABS-9
Thermodynamics Theoritical Investigation for Synthesis of Pyridine from Pyrylium Salt Using Density Functional Theory Selmi Fiqhi Khoiriah (a), Agil Aprianto (a), Putri Kania (a), Rafi Nur Fauzi (b), Mita Nurhayati (a, c*) (a) Program Studi Kimia, Departemen Pendidikan Kimia, Universitas Pendidikan Indonesia, Jalan Dr. Setiabudhi no. 229, Bandung, Jawa Barat (b) Program Studi Pendidikan Kimia, Departemen Pendidikan Kimia, Universitas Pendidikan Indonesia, Jalan Dr. Setiabudhi no. 229, Bandung, Jawa Barat (c) Department of Advanced Science and Technology Convergence, Kyungpook National University, Sangju-si, Gyeongsangbuk-do, South Korea Abstract Pyridine is a heterocyclic compound which is widely used as an ingredient in medicines, vitamins, food flavors, pesticides, dyes, adhesives, and others. Currently, pyridine synthesis is carried out with coal tar as a raw material, which is a non-renewable natural resource. In this research, a theoretical study was carried out to evaluate the synthesis process of pyridine using pyrylium salt as an alternative raw material to displace coal tar. This study also aims to simulate the pyridine synthesis and the energy required or released in the process. Density Functional Theory (DFT) method was employed to calculate some thermodynamic properties of the species involved in the reaction such as enthalpy, entropy, and Gibbs free energy in vacuum and solvated model in order to study the progress of reaction and mechanism. Based on the calculation results, the lowest value of enthalpy, entropy, and free energy Gibbs is obtained when the reaction takes place in a vacuum. The change of entropy and free Gibbs energy of reaction was not predominantly affected by the degree of polarity of the solvent. Meanwhile, the enthalpy of reaction simulated in water solvent is higher than in the ethanol solvent. The synthesis reaction of pyridine from pyrylium salt is exothermic and exergonic because it has a negative value of enthalpy change and Gibbs free energy at 298.15 K, which is potential to be done in room temperature without extreme condition control. Keywords: Pyridine synthesis, Pyrylium salts, DFT, Computational chemistry Share Link | Plain Format | Corresponding Author (Selmi Fiqhi Khoiriah)

199	Theoretical and Computational Chemistry	ABS-46
Predicting the interaction between organic layer and metal substrate through DFT and electrochemical approach Abdelkarim Chaouiki, Wail Al Zoubi, Young Gun Ko Yeungnam University Abstract Heterocyclic compounds are the promising biological compounds as nature-friendly for the corrosion protection of metallic surface. In this work, three heterocyclic compounds such as 1-azanaphthalene-8-ol (8-AN), 2-methylquinoline-8-ol (8-MQ), and 8-quinolinol-5-sulfonic acid (8-QSA) were used as green compounds, and their anti-corrosion performance for AZ31 Mg in saline water was discussed on the basis of impedance interpretation and surface analysis. Findings found that the electrochemical performance was improved in the order of 8-AN > 8-MQ > 8-QSA, demonstrating the electron donor effect of N-heterocycles to form coordination complexes on the magnesium surface. From the electrochemical performance, the protective layer constructed at the optimal concentration reinforces the barrier against aggressive environments, with potential inhibition efficiency of 87.4%, 99.0%, and 99.9% for 8-QSA, 8-MQ, and 8-AN, respectively. Quantum chemical parameters and electron density distribution for free organic species in the absence and presence of Mg2+ cation were evaluated using density functional theory (DFT). Upon the formation of coordination complexes between organic compound and Mg2+, energy gap underwent change about &#8710-E = 5.7 eV in the 8-AN/Mg2+ system. Furthermore, the adsorption of heterocyclic compounds on the Mg surface reveals the formation of strong covalent bonds with Mg atoms, which further confirmed by the electron density difference and projected density of states analyses. In fact, three inhibitors can adsorb on the metal surface in both parallel and perpendicular orientations via C, O and N atoms and the results indicated that parallel configurations are energetically more stable, in which the adsorption energies are -4.48 eV (8-AN), -4.28 eV (8-MQ) and -3.82 eV (8-QSA) compared to that of perpendicular adsorption (-3.65, -3.40, and -2.63 eV). As a result, experimental and theoretical studies were in well agreement and confirm that the nitrogen and oxygen Keywords: Organic layer- Heterocyclic compounds- Electrochemical behavior- DFT modeling. Share Link | Plain Format | Corresponding Author (Abdelkarim CHAOUIKI)

200	Theoretical and Computational Chemistry	ABS-49
A Computational Study of 68Ga-Dota-Ethambutol Synthesis : The Reaction Mechanism Catalyzed by Boric Acid using Hybrid meta-GGA DFT Functional and Diffuse-Polarized Basis Sets Badra Sanditya Rattyananda (1,3,*) Muhamad Abdulkadir Martoprawiro (2) Duyeh Setiawan (3) and Suci Zulaikha Hildayani (4) 1. Master Program of Chemistry, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology 2. Physical Chemistry Group,Department of Chemistry, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology 3. National Research & Innovation Agency of Indonesia 4. Doctoral Program of Chemistry, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology * Corresponding author, phone/WA: +6285218544675, email: badra.sanditya.rattyananda[at]brin.go.id Abstract Indonesia was a country with the most tuberculosis cases in Southeast Asia. For some special cases in patients with low immunity TB bacteria was found to have spread to the bones and brain called tuberculous meningitis. It Diagnosis was difficult using conventional methods thus BATAN has developed a gamma ray-based radiopharmaceutical for diagnosing tuberculous meningitis named 99mTc-Ethambutol. The gamma-ray radiopharmaceuticals has problems in resolution of imaging and Increasing it can be done by changing the radioisotope to a positron-based radioisotope, one of them was Gallium-68. 68Ga-DOTA-Ethambutol was a candidate positron-based compound to improve the diagnostic imaging results of Tuberculous meningitis. The computation study simulated using Orca 5.0.3, Geometry optimization calculation using the medium functional B3LYP and def2-SVP basis set to reduce computational cost, followed by frequency energy using the hybrid meta-GGA functional M06-2X and cc-PVTZ basis set. The reaction has 3 stages of reaction, namely deprotonation, nucleophilic attack and the release of leaving group. The Transition state of its reaction mechanism calculated used M06-2X and diffuse-polarized basis set def2-SVPD that obtained activation energy required for deprotonation was 152.86 kJ/mol, 216.73 kJ/mol for nucleophilic attack and 44.55 kJ/mol for leaving group release. The synthesis became under Exothermic reaction with heat release -57.06 kJ/mol and classified as spontaneous reaction with Gibbs free energy found -39.16 kJ/mol. The rate-determining step identified at the nucleophilic attack reaction which has the largest energy barrier. The quantum computational expect can reduce the time and cost of radiopharmaceutical research which was very large. Furthermore, it was necessary to due molecular docking and dynamic studies to explain the suitability interaction between 68Ga-DOTA-Ethambutol and TB receptors. The predicted properties also can be used as a guide in laboratorium. Keywords: 68Ga-DOTA-Ethambutol, Radiopharmaceutical, Reaction Mechanism, M06-2X, def2-SVPD, Transition state Share Link | Plain Format | Corresponding Author (Badra Sanditya Rattyananda)

201	Theoretical and Computational Chemistry	ABS-65
DENSITY FUNCTIONAL THEORY (DFT) METHOD ON REACTION MECHANISM OF SHORT SYNTHESIS MOLNUPIRAVIR Aristia Pratiwi Meliawati (1,3*), Muhamad Abdulkadir Martoprawiro(1), Aminatus Arifah(1), Badra Sanditya Rattyananda(2), Merika Indri Widayanti(1), Nelly Safitri Anwari(1), Selvi Anasha(1) 1)Master^s Program in Chemistry, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology (Jl. Ganesha No.10, Bandung 40132, Indonesia) 2)National Research and Innovation Agency (Jl. Tamansari No.71, Bandung 40132, Indonesia) 3)State Vocational High School 6 Garut (Jl. Raya Nagreg-Limbangan KM. 01, Balubur Limbangan, Garut 44186, Indonesia) * aristiapm[at]gmail.com Abstract Molnupiravir (MK-4482, EIDD-2801) was a prodrug recommended by the Emergency Use Authorization (EUA) from the Food and Drug Administration (FDA) to treat emergencies due to Covid-19. The synthetic route of molnupiravir involves transesterification and transamination from cytidine. Transesterification of cytidine is conducted by immobilized Candida antarctica lipase B and isobutyric oxime ester. Afterward, it was followed by a transamination reaction between hydroxylamine and intermediate. Transesterification uses 1,4-dioxane as a solvent, while transamination uses isopropyl alcohol as the solvent. The synthesis reaction experiment was carried out in two schemes. The first scheme was to carry out the transesterification reaction followed by the transamination reaction. The second scheme was the reverse reaction of the first one. In which transamination was followed by transesterification. The experimental results show that scheme-1 produces products as much as 75%, while scheme-2 has 37%. The study of the reaction mechanism for the synthesis of molnupiravir was carried out using the Density Functional Theory (DFT) method and the theoretical level of B3LYP that were calculations performed using the base set def2-SVP without involving a catalyst. From the computational result, the transesterification occurs concerted without going through an intermediate. The reaction needs activation energy of 128.09 kJ/mol for scheme-1 and 127.93 kJ/mol for scheme-2. It means that the transesterification reaction in both pathways can produce several products that are not much different. The transamination reaction passes through two intermediates. The first was a protonation reaction with an activation energy of 106.57 kJ/mol in scheme-1 and 165.06 kJ/mol for scheme-2. The following reaction is the substitution of ammonia with hydroxylamine. At this stage, scheme-1 requires activation energy of 146.84 kJ/mol, and scheme-2 requires an activation energy of 204.71 kJ/mol. The last rea Keywords: molnupiravir, MK-4482, EIDD-2801 DFT, transesterification, transamination, reaction mechanism Share Link | Plain Format | Corresponding Author (Aristia Pratiwi Meliawati)

202	Theoretical and Computational Chemistry	ABS-84
QSAR, design, and molecular docking study of phenoxypyridine derivatives as protoporphyrinogen IX oxidase inhibitors Hafiz Aji Aziz, Chandra Pratama Putra, Wita Putri Nirwani, Hendrawan Universitas Pendidikan Indonesia Abstract Herbicides are very important used in crop production to protect them from competition with weeds to increase crop yields and quality of crop. The herbicide protoporphyrinogen oxidase (PPO, EC 1.3.3.4) acts on the protoporphyrinogen oxidase enzyme, which catalyzes the oxidation of protoporphyrinogen IX to protoporphyrin IX. In this study, a series of new phenoxypyridine derivatives were developed as protoporphyrinogen oxidase inhibitors. In this case, QSAR (Quantitative Structure-Activity Relationship) was used to determine the binding mode and its structural stability as a structure of a protoporphyrinogen oxidase inhibitor, to make a protoporphyrinogen oxidase inhibitor based on the synthesized compound. We used 21 data on phenoxypyridine derivatives containing coumarins with activity (IC50) obtained from previous studies and then made logIC50 as homogeneity of research data. The structure was optimized using the AM1 semi-empirical method and calculations were performed using the ORCA software. In modeling the QSAR equation, the BuildQSAR software using the Multiple Linear Regression (MLR) method is used and the equation search algorithm uses a genetic algorithm. The resulting QSAR equation is \[logIC_{50}=7.5121\left(\pm3.3992\right)\left[C17\right]+0.0230\left(\pm0.0074\right)\left[Energy\right]-244.3649\left(\pm87.0787\right)\left[C6\right]+38.4466\left(\pm12.6370\right)\] can be used to calculate the predicted log IC50 value of new compound design. The biological activity of phenoxypyridine derivatives containing coumarins as protoporphyrinogen oxidase inhibitors in the form of log IC50 predicted by the MLR method was QSAR with a value of \[R_{tr}^2=0.820836, Q^2=0.644, F=19.917, R_{val}^2=0.9575, RMSE=0.313593577\] The new phenoxypyridine derivative compound that has the most potential as a protoporphyrinogen oxidase inhibitor with the lowest binding energy value is compound A9 with logIC50 value is -3.66545 and its energy is -7.50 kcal/mole. Keywords: QSAR, docking, phenoxypyridine, PPO inhibitor Share Link | Plain Format | Corresponding Author (Chandra Pratama Putra)

203	Theoretical and Computational Chemistry	ABS-96
QSAR, Design, and Molecular Docking of Potential Anti-Cancer Chromene-Dione Derivatives H. A. Aziz, W. P. Nirwani, C. P. Putra, H. Hendrawan Chemistry Study Program, Indonesia University of Education Abstract Cancer, which happened due to error in cell replication is one of the deadliest diseases in the world. In this study, we performed a Quantitative Structure-Activity Relationship study of Chromene-Dione derivatives as potential anti-cancer drug based on H1229 cell line test, designed some new Chromene-Dione derivatives with better predicted activity, and performed molecular docking calculation to predicts its interaction with the receptor protein. QSAR equation search is performed using genetic algorithm on BuildQSAR software on optimized structure of the compounds. The geometry optimization is performed on Orca 4.2.1 using DFT/B3LYP/6-31G methods. Molecular docking calculation is performed using genetic algorithm on AutoDock 4 software, and the calculation results is visualized using Biovia Discovery Studio. QSAR equation search resulting is 5 equations that is considered to be robust enough to be used in designing new compounds. One of the equations is: \[logIC_{50}=-0.0012\left(\pm0.0002\right)TDB7m+0.0007(\pm0.0003)TDB8m-0.0134(\pm0.0052)RDF35e-1.6834\left(\pm0.6028\right)E2v+0.9843\left(\pm0.3257\right)E3v+2.1491\left(\pm0.2351\right)\] Based on those 5 equations, we designed several compounds, 2 of which produced activity that is better than the best compound in the data set, thus indicating new potential compounds. To see the possible interaction with protein, we performed molecular docking calculation with 3 receptors which are AKT1 (PDB ID: 3MV5), EYA2 (PDB ID: 5ZMA), and EGFR (PDB ID: 1M17). Molecular docking calculation show that all 6 complexes indicating similar interaction with the native ligand, with one complex in particular (C14-AKT1) has lower energy (-7.61 kcal/mole) than the reference native complex of XFE-AKT1 (-7.51 kcal/mole) with acceptable RMSD. Keywords: QSAR, Molecular Docking, Anticancer, Chromene-Dione Derivatives Share Link | Plain Format | Corresponding Author (Wita Putri Nirwani)

204	Theoretical and Computational Chemistry	ABS-171
In Silico Screening of Pyridinium-based Aqueous Ionic Liquid-Water Cosolvents for Lipase Catalyzed Esterification Reaction to Synthesize Dimethyl Itaconate Oktavianus Hendra Cipta, Anita Alni, Made Puspasari Widhiastuty, Rukman Hertadi Bandung Institute of Technology Abstract Dimethyl itaconate is an ester derivative of itaconic acid. The main role of dimethyl itaconate is to be a monomer for polyester synthesis. One of the method that can be used for dimethyl itaconate synthesis is to use a biocatalyst that has an advantage in the specificity of the reaction product. One of the enzymes that have been used as a biocatalyst for dimethyl itaconate synthesis is lipase. Lipase can catalyze the esterification between itaconic acid and methanol to dimethyl itaconate when using a non-aqueous solvent, whereas itaconic acid has very low solubility in non-aqueous solvent. The alternative that can be used in this problem is ionic liquids. The ionic liquid that will be used in this study is a pyridinium based ionic liquid, which has been proven to increase esterification activity and the specificity of the product. Pyridinium based ionic liquid is more easily degraded so that it is more environmentally friendly than imidazolium based ionic liquid that have been used in previous study. Using computational study to screening which ionic liquid is compatible with lipase is very useful so we can synthesize only the most compatible ionic liquid. Itaconic acid docked to lipase catalytic site and then using molecular dynamics simulation to simulate the complex in ionic liquid-water co-solvent system. Final trajectory from molecular dynamics simulation used as starting conformation for quantum calculations using orca. Optimization energy calculation from itaconic acid substrate that get docked into lipase in water is around -491.5 HF and in 4-tetrafluoroborate pyridinium ionic liquid-water system is around -515 HF which lower than optimization energy in water. From this founding we hope 4-tetrafluoroborate pyridinium can help lipase to catalyze itaconic acid substrate. Other ionic liquid variation can be calculated too so the data can be more reliable. Keywords: quantum chemistry, docking, molecular dynamics, lipase, ionic liquid Share Link | Plain Format | Corresponding Author (Oktavianus Hendra Cipta)

205	Theoretical and Computational Chemistry	ABS-189
STUDY OF THE EFFECT OF IMIDAZOLE DERIVATIVE IONIC LIQUIDS ON LIPASE DYNAMICS AND STABILITY WITH MOLECULAR DYNAMICS SIMULATION METHOD Asep Iin Nur Indra, Rukman Hertadi, Reza Aditama Bandung Institute of Technology Abstract Lipase is a potential enzyme for various catalysis reactions. In industry, lipase is commonly used in organic solvents environment so that its activity is increased. However, using organic solvents in the food and medical industries are very limited because of its volatile nature and high toxicity. Therefore, further research is developed using ionic liquids which can replace the role of organic solvents. Ion liquid has several advantages such as non-volatile, reusable and more environmentally friendly. In previous studies, it was known that imidazole derivative ionic liquids were reported to be able to increase lipase activity by 28.9%. However, the cause of the increase in activity was not yet known. This study aims to determine the stability of lipases in liquid ion derivatives of imidazole in silico. A lipase system with a water solvent and four imidazole derivative ionic liquids was prepared and a molecular dynamics simulation was carried out for 100 nanoseconds at 40 \( ^o C \) and 100 \( ^o C \). Simulation results show that lipase stability is thought to have a relationship with its catalytic activity. Lipase system with ionic liquid [EMIM]Br remains stable at 100 \( ^o C \) as indicated by an RMSD value of 2.9 Angstrom. From the results of the RMSF analysis it is known that the fluctuation of the lipase system with ionic liquid [EMIM]Br is maintained quite low but still maintains the mobility of the residue in the lid lipase area. The ionic liquid [EMIM]Br also surrounds lipase more than any other ionic liquid. It can be concluded that [EMIM]Br can stabilize the structure of proteins by protecting around lipases while maintaining the dynamics of the lid area. These results have provided information at the atomic level regarding the stability of lipases in various ionic liquids. Keywords: Lipase, ionic liquid, EMIMBr, molecular dynamics simulation Share Link | Plain Format | Corresponding Author (Asep Iin Nur Indra)

206	Theoretical and Computational Chemistry	ABS-205
IN SILICO STUDY: MOLECULAR DOCKING STUDY OF LEAVES SOURSOP (Annona muricata L.) ACTIVE COMPOUNDS AS ANTIHYPERLIPIDEMIA Riska Prasetiawati (a), Rubi Rahman Fauji (a), Benny Permana (b), Novriyanti Lubis (a*) a, Department of Analytical Pharmaceutical Chemistry Faculty of Mathematics and Natural Sciences, University, Garut 44151, Indonesia b, School of Pharmacy, Bandung Institute of Technology, Jl. Ganesha 10, Bandung 40132 Abstract Hyperlipidemia is a condition where is the level of fat increase in the blood circulation. This condition can cause the narrowing of the arteries called atherosclerosis. Soursop leaves (Annona muricata L.) are traditionally used as anticholesterol, antibacterial, anti-inflammatory and antioxidant. There are 63 known compounds contained in soursop leaves. The purpose of this study was to search candidate compounds from soursop leaves that have activities as antihyperlipidemic through interactions with HMG CoA reductase and PPAR&#945- receptor carried out in silico by molecular docking method, include prediction of absorption, distribution, and toxicity. Molecular docking results showed chlorogenic acid had a good affinity for the HMG CoA reductase enzyme, the value of \triangleG -8.55 kcal/mol and KI value of 543.74 \muM, while the comparison compound produced \triangleG -7.33 kcal/mol and KI value of 4.24 \muM. Toward PPAR&#945- receptor, compound with the best affinity was solamin, with the value of \triangleG -8.14 kcal/mol and KI value of 1.09 \muM, while the comparison compound produced avalue of \triangleG -7.17 kcal/mol and Ki value 5.51 \muM. Solamin fulfills Lipinski^s rule of five while chlorogenic acid didn^t fulfills this rule. Both compounds had good absorption and distribution profiles and are not carcinogenic but mutagenic chlorogenic acid. In conclusion, both compounds could be used as potential candidates for hyperlipidemia therapy Keywords: HMG CoA reductase enzyme, molecular docking, PPAR&#945- receptors, soursop leaves (Annona muricata L.) Share Link | Plain Format | Corresponding Author (Riska Prasetiawati)

207	Theoretical and Computational Chemistry	ABS-212
Binding investigation of pyrimethamine derivatives complexes with wild-type and mutant P. falciparum dihydrofolate reductase using MD simulations and quantum chemical calculations Sasipha seetin a,b, Patchreenart Saparpakorn a,b, Jarunee Vanichtanankulc, Sumalee Kamchonwongpaisan c, and Supa Hannongbua a,b* a Department of Chemistry, Faculty of Science, Kasetsart University, Chatuchak, Bangkok 10900, Thailand b Center for Advanced Studies in Nanotechnology for Chemical, Food and Agricultural Industries, Kasetsart University, Chatuchak, Bangkok 10900, Thailand c National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, 113 Thailand Science Park, Phahonyothin Road, Khlong Nueng, Klong Luang, PathumThani 12120, Thailand *Corresponding authors: Supa Hannongbua, email: fscisph[at]ku.ac.th Abstract Plasmodium falciparum dihydrofolate reductase-thymidylate synthase (pfDHFR-TS) is an important target enzyme and is regarded as an interesting target for designing antimalarial drugs. However, drug resistance is the main reason for unsuccessful malaria treatment. A series of des-Cl and m-Cl phenyl analogues of pyrimethamine with various flexible 6-substituents were investivated, based on MD simulations, quantum chemical calculations, and MM-PBSA, to comprehend of how the potential inhibitor, compound27, interact with wild-type (wtPfDHFR), quadruple-mutant (qmPfDHFR), and human (hDHFR) enzymes. Compound27 complexed with the three DHFR enzymes were obtained to reach the stability by using MD simulations, followed by confirming the binding interaction of key residues which were analyzed by quantum chemical calculations and MM-PBSA simulation. It was found that Asp54 and Phe58 play important roles in wtPfDHFR and qmPfDHFR, while Arg59 and Arg122 found interactions with compound 27 in qmPfDHFR system. On the other hand, the position of Arg122 in wtPfDHFR and qmPfDHFR is found to be equivalent to Arg70 which is unlikely to bind in hDHFR. For the hDHFR, strong hydrophobic interactions with Phe34 and hydrogen bonding with Ile7, Val8, and Glu30 were found. According to key interaction findings of compound27, it can provide valuable suggestions for further novel antimalarials development. Keywords: Antimalarials, DHFR-TS, Molecular dynamics simulations, MM-PBSA, Quantum chemical calculations Share Link | Plain Format | Corresponding Author (Sasipha Seetin)

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