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All Journal Indonesian Journal of Chemistry
Rashid, Umer
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Chemical Engineering, Chemistry & Bioengineering Chemistry

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Synthesis of Water-Soluble Menthol Derivatives Using Response Surface Methodology Nisar, Shafaq; Hanif, Muhammad Asif; Rashid, Umer; Jilani, Muhammad Idrees; Bhatti, Ijaz Ahmad; Ali, Imtiaz; Zieniuk, Bartłomiej
Indonesian Journal of Chemistry Vol 24, No 6 (2024)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.94761

Abstract

In this study, menthol was glycosylated with starch in the presence of α-amylase to produce menthyl maltoside (MenM) as the primary product. Optimization of the experimental parameters, including the menthol-starch ratio, enzyme concentration, temperature, and time, was performed using response surface methodology (RSM). The RSM-generated model displayed adequate accuracy and reasonable predictability for the MenM yield under the specified experimental conditions. Under the optimized reaction conditions of the menthol-to-starch ratio of 1:3 (50 °C, 18 h) and enzyme concentration of 50 U, the highest yield of MenM (23.7%) was obtained. Fourier transform infrared and nuclear magnetic resonance spectroscopies were employed to analyze the synthesized menthol derivative MenM. Compared with standard menthol, the synthesized menthol derivatives displayed various biological activities, including antioxidant, antibacterial, antifungal, and insecticidal properties. The results of this study demonstrate the effectiveness of RSM-optimized synthesis of MenM from the glycosylation of menthol with starch. This study showed that MenM is highly soluble in water and can be easily stored owing to its non-volatile nature.
Enhancing the Energy Content of Melawan Coal through H2SO4 and NaOH Demineralization Ngulde, Aliyu Buba; Wan Ab Karim Ghani, Wan Azlina; Nawi, Nazmi Mat; Rashid, Umer; Silas, Kiman
Indonesian Journal of Chemistry Vol 25, No 3 (2025)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijc.100059

Abstract

The objective of this study was to compare the calorific values, proximate analysis, ultimate analysis, SEM-EDX, XRF, FTIR spectroscopy, and TGA of the control feedstock and coal samples treated with different acid-alkali formulations. We also evaluated the effectiveness of the acid and alkali treatments, individually and in combination, on the structural and chemical properties of Melawan coal. The TGA results indicated that all treated coal samples showed reduced weight loss compared to raw coal, indicating the removal of minerals and volatile components owing to the treatment processes. Based on the DTG curve, the combination treatment (acid followed by base) somewhat stabilizes the coal, leading to a broader and less intense peak. EDS analysis revealed that both H2SO4 and NaOH treatments, individually and in combination, significantly altered the elemental composition of the coal. According to FTIR analysis, the presence of carbonyl groups can affect the performance of coal in processes such as gasification, pyrolysis, or combustion, making it a key functional group of interest for evaluating post-treatment coal properties. The removal of mineral impurities can lead to a higher calorific value, making coal more suitable for energy generation applications.
Co-Authors Ali, Imtiaz Bhatti, Ijaz Ahmad Hanif, Muhammad Asif Jilani, Muhammad Idrees Nawi, Nazmi Mat Ngulde, Aliyu Buba Nisar, Shafaq Silas, Kiman Wan Ab Karim Ghani, Wan Azlina Zieniuk, Bartłomiej