Production of glycerol 1,2-carbonate from glycerol with aid of ionic liquid as catalyst

The surplus formation of glycerol (glycerine or 1,2,3-propanetriol) during biodiesel production has led to a major concern. Glycerol price has dropped and it exerts a great impact on the refined glycerol market. This has triggered an extensive research focus to find an innovative way to revalorize glycerol and transform to value-added chemicals. Yet, it is undeniably a necessary move towards achieving greener and sustainable processes. For instance, glycerol 1,2-carbonate (4-hydroxymethyl-1, 3-dioxolan-2-one) is currently one of the most celebrated glycerol derivatives that captured arising scientific and industrial attentions due to its extensive potential applicability. This cyclic ester of glycerol with carbonic acid is reasonably reactive as it has reactive electrophilic and nucleophilic sites yet having low toxicity and good biodegradability. This important product has attracted numerous applications in chemical industry such as being the novel component of gas-separation membranes, non-volatile solvent for dyes, lacquers, detergents, adhesives and cosmetics, electrolyte ingredient of lithium-based batteries, surfactants and lubricating oils. Likewise, glycerol 1,2-carbonate is beneficial not only as a polar high boiling solvent or intermediate for the synthesis of polycarbonates, polyesters, polyamides and hyper branched polyethers, it also can be used as green substitution for petro-derivatives compounds (ethylene carbonate or propylene carbonate). The reactivity of glycerol 1,2-carbonate having both electrophilic and nucleophilic sites allows for the synthesis of new polymeric materials such as glycidol which is primarily being used in the production of a number of polymers. Please click Additional Files below to see the full abstract

PENERAPAN MODEL PEMBELAJARAN BERBASIS MASALAH DENGAN PENDEKATAN SAVI UNTUK MENINGKATKAN HASIL BELAJAR BIOLOGI SISWA KELAS XI IPA 2 SMAN 8 BENGKULU

Penelitian ini bertujuan untuk mengetahui aktivitas guru, aktivitas siswa, dan peningkatkan hasil belajar siswa kelas XI IPA 2 SMAN 8 Bengkulu dalam menerapkan model Pembelajaran Berbasis Masalah dengan pendekatan SAVI. Jenis penelitian ini adalah penelitian tindakan kelas yang dilakukan dalam dua siklus. Metode yang digunakan adalah metode deskriptif. Data yang dikumpulkan dalam penelitian ini yaitu data kualitatif dan kuantitatif. Instrumen yang digunakan yaitu lembar observasi dan lembar tes. Hasil penelitian diperoleh adanya peningkatan pada aktivitas guru, aktivitas siswa, dan hasil belajar siswa. Rata-rata skor aktivitas guru pada siklus I yaitu 19,5 (baik) meningkat disiklus II menjadi 23 (baik). Pada aktivitas siswa rata-rata skor siklus I yaitu 18 (baik) meningkat disiklus II menjadi 20 (baik). Peningkatan aktivitas guru dan aktivitas siswa diikuti pula oleh peningkatan hasil belajar siswa. Pada siklus I hasil belajar siswa memperoleh persentase klasikal 58,82% meningkat disiklus II menjadi 85,29% (ketuntasan klasikal 85%). Berdasarkan hasil penelitian dapat disimpulkan bahwa model pembelajaran berbasis masalah dengan pendekatan SAVI dapat meningkatkan hasil belajar siswa pada materi sistem indera. Kata kunci: Pembelajaran Berbasis Masalah, Pendekatan SAVI, Hasil Belaja

Dissolution of oil palm biomass by alkyl-imidazolium ionic liquids for efficient enzymatic hydrolysis.

The dissolution of oil palm biomass by ionic liquids (ILs) was comparatively studied. The ionic liquids, 1-ethyl-3-methylimidazolium chloride ([emim]Cl), 1-butyl-3-methylimidazolium chloride ([bmim]Cl) and 1-ethyl-3-methylimidazolium acetate ([emim]OAc) were used to dissolve oil palm biomass and cellulose fibers which are empty fruit bunches (EFB), oil palm frond (OPF) and oil palm trunk (OPT). Dissolution of 5 wt. % (0.1 g) of fibers/ ILs solutions were conducted at 100 °C under inert atmosphere. The heating time for complete dissolution was optimized. It has been shown that [emim]OAc is the best solvent for dissolution of oil palm biomass compared to [emim]Cl and [bmim]Cl. EFB, OPF and OPT fibers dissolved in [emim]OAc shows more than 95 % w/w of dissolution after 16 h of heating, while EFB and OPF fibers dissolved more than 85 % w/w after being heated more than 48 h in [emim]Cl and [bmim]Cl. Cellulose fibers were successfully dissolved after 2 - 3 h of heating in all ILs tested. Fourier-transform infrared spectroscopy (FT-IR)confirmed the absorbance band at 1729 cm-1 and 1512 cm-1 which correspond to hemicellulose and lignin, respectively disappeared after regeneration process indicating that they were diminished after the washing step. Regenerated cellulose-rich solids were obtained in amorphous form (cellulose II), thus decreasing the crystallinity index (CrI) values. The CrI value for regenerated EFB, OPF and OPT fibers decreased after 12 h of dissolution in [emim]OAc which were 79.3, 80.3 and 79.3 % to 39.8, 38.3 and 40.2 %, respectively. The accumulated glucose released was reached to a level approximately 13.8 mg/ml which was at least ten-fold higher than that of untreated fibers samples which only 3.19 mg/ml. From NMR study, the six signals of the unmodified anyhdroglucose unit appear clearly at 102.5 (C-1), 79.67 (C-4), 76.44 (C-5), 75.24 (C-3), 74.19 (C-2) and 60.15 ppm (C-6). Through swelling and dissolution mechanism of fibers, disintegration into rod-like fragments, ballooning followed by dissolution and homogeneous swelling were clearly observed for both oil palm biomass and cellulose fibers. Observation under scanning electron micrograph (SEM) showed that, the loose structures of oil palm biomass fibers and a greater part of the smaller fibrils seemed to be absent in the cellulose-rich solids were observed after regeneratio

Conversion of glycerol to glycerol carbonate via transesterification using 1-Ethyl-3-Methylimidazolium acetate catalyst / Zati Ismah Ishak

In the present research, the synthesis of glycerol carbonate by transesterification of glycerol with diethyl carbonate in a green and efficient process catalyzed by ionic liquid was comparatively studied. A series of imidazolium and ammonium-based ionic liquids with different anions and conditions optimization (reaction temperature, reaction time, diethyl carbonate/glycerol ratio, solvent and catalyst loading) were screened for the best catalytic activity towards glycerol carbonate synthesis with respect to glycerol conversion and glycerol carbonate yield. It has been revealed that 1-ethyl-3-methylimidazolium acetate ([Emim][Ac]) remarks the highest activity towards glycerol conversion and glycerol carbonate yield of 93.5%, and 88.7%, respectively at 120 ᵒC, 2.0 hours, molar ratio of diethyl carbonate/glycerol of 2, 0.50 mol% [Emim][Ac] loading with 2.0 wt.% water content. The peak intensities at 1262 cm-1 and 923 cm-1 corresponding to O-H bending and 3387 cm-1 corresponding to O-H stretching in glycerol were reduced indicate to glycerol being converted to glycerol carbonate. Meanwhile, the peak at 1750 cm-1 corresponding to C=O and also peaks between 1200 cm-1 to 1000 cm-1 corresponding to C–C and C–O stretching of 2-hydroxyethyl chain showed an increase in intensity. These supported the presence of glycerol carbonate while reaction was in progress. Glycerol carbonate peaks at 61.5 ppm, 67.0 ppm, and 77.5 ppm corresponding to –CH2–O-, –CH2–OH and –CH–, respectively are gradually increased when the reaction solution turned into a single phase at 1.5 hours. Response surface methodology (RSM) showed the interactive effects between selected reaction parameters towards glycerol conversion and glycerol carbonate yield with 92.4% and 91.8%, respectively at optimum reaction conditions; reaction temperature of 118 ᵒC, at 1.8 hours with 2.2 of diethyl carbonate/glycerol ratio and 0.42 mol% [Emim][Ac] loading. Recyclability study showed insignificant reduction of glycerol conversion from recovered [Emim][Ac] indicating that [Emim][Ac] could be reused for approximately three times. All the respective peaks of [Emim][Ac] can be comparably resolved with little variation in chemical shift of 1H spectra NMR for each cycle, thus revealing that [Emim][Ac] was successfully recovered with no degradation on its structure. The result of the computational study using a General Atomic and Molecular Electronic Structure System (GAMESS) software clearly demonstrated that the activation of glycerol proceeds mainly through the hydrogen bonding interaction with [Ac]- anion. On the other hand, diethyl carbonate is also capable of forming hydrogen bonding with imidazolium ring proton at carbon 2 position and hydroxyl group of glycerol. The proposed mechanism of glycerol carbonate synthesis agreed well with the theoretical computational study

Effect of Ionic Liquids on Oil Palm Biomass Fiber Dissolution

Ionic liquids (ILs) were used in the dissolution of oil palm biomass, primarily empty fruit bunches (EFB), oil palm fronds (OPF), and oil palm trunks (OPT). These ILs acted as alternative solvents that could dissolve biopolymer molecules up to 5 wt.%. The IL, [emim][OAc] was the best solvent, dissolving EFB, OPF, and OPT of 99%, 100%, and 97%, respectively, at 100 ⁰C and 16 h. The lignin content of the regenerated oil palm solids for all biomass was quantified and showed significant reduction up to 35%; fiber length was also reduced as the heating time increased after IL dissolution. Also, the effect of ILs on the different parts of oil palm biomass fibers was thoroughly studied. The lignin content was quantified