Free-volume hole size evaluated by positron annihilation lifetime spectroscopy in the amorphous part of poly ( ethylene a b s t r a c tChitosan is a linear copolymer composed of (1 / 4)elinked 2-acetamido-2-deoxy-b-D-glucan (GlcNAc) and 2-amino-2-deoxy-b-D-glucan (GlcN) units in varying proportions, having a high molecular weight and strong intra-and intermolecular hydrogen bondings. Sonication has become an alternative for degrading chitosan into low-molecular-weight chitosan (LMWC), chitosan oligomers and glucosamine. In this study, chitosan was treated with sonication at 40 C and 60 C for 30 min and 120 min with various acetic acid concentrations (0.2% v/ve1% v/v); the very-low-concentration acid solution functioned both as a solvent and catalyst. After sonication, the samples were tested for changes in molecular weight, water soluble proportion of chitosan (chitosan oligomers and glucosamine), degree of deacetylation, degree of crystallinity, and morphology. The soluble and insoluble product yields at low concentration (0.5% v/v) at 40 and 60 C were 33.66e39.37 % and 32.43e34.26%, respectively. The main product was 5-hydroxy methyl furfural with composition 92.16e99.43%. At high concentrations (1% v/v), the soluble product and insoluble yields were 43.72e49.74% and 43.1e50.26%, respectively. The main product was glucosamine with composition 77.75e93.16% of glucosamine. There were changes in the morphology and crystallinity of the degraded chitosan, but no change in the chemical structure. The crystallinity had a tendency to increase. The degree of deacetylation tended to decrease due to the glucosamine breakage.

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The production of biofuel by hydrocracking of Sunan candlenut oil as renewable energy can substitute fossil energy. The purpose of this work is to produce biofuel by hydrocracking of Sunan candlenut oil with Co-Ni/HZSM-5 catalyst. The catalyst was prepared by incipient wetness impregnation method. The characterization of catalyst was determined by X-Ray Diffraction (XRD) and nitrogen adsorption-desorption isotherms. The functional groups of the hydrocarbon was determined by Fourier Transform Infrared (FT-IR). The hydrocarbon composition was determined by Gas Chromatography Mass Spectrometry (GC-MS). The results showed that biofuel composition consist of 0.14 area% isoparaffins, 12.29 area% cycloparaffins, 6.87 area% normal paraffins, 4.18 area% olefin, and 10.52 area% aromatics, and oxygenated compounds including 35.03 area% carboxylic acids. It was necessary to be done that the oxygenated compounds in biofuel were eliminated to produce the abundant paraffin hydrocarbons at reaction temperature above 350 o C.

This research aims to investigate the effect of various reaction temperatures on the hydrocracking of Cerbera manghas oil to produce biofuel as a paraffin-rich mixture of hydrocarbons with Co-Ni/HZSM-5 catalyst. Co-Ni/HZSM-5 catalyst was prepared by incipient wetness impregnation. The catalyst was characterized by X-ray diffraction (XRD), N 2 physisorption according to the Brunauer-Emmet-Teller (BET) method, and atomic absorption spectrometry (AAS). The hydrocracking reaction was carried out in a pressure batch reactor, reaction temperatures of 300-375 o C for 2 hours, reactor pressure of 15 bar after flowing H 2 for at least 1 hour, and a catalyst/oil ratio of 1 g/200 ml. The hydrocarbon composition was determined by gas chromatography-mass spectrometry (GC-MS). With the Co(0.88%)-Ni(3.92%)/HZSM-5 catalyst, the highest yield for gasoil was 46.45% at temperature of 350 o C. At this reaction temperature condition, the main abundant hydrocarbon compounds in gasoil-like hydrocarbon were n-paraffin, i.e. pentadecane of 20.06 area% and heptadecane of 14.13 area%. Biofuels produced showed that abundant hydrocarbon compounds were different at different reaction temperatures. Iso-paraffin with low freezing point and good flow property were not found in gasoil-like hydrocarbon. Isomerization depends on reaction condition and type of catalyst.

This research was aimed to convert Calophyllum inophyllum kernel oil into liquid fuel through hydrocracking process using non-sulfide CoMo catalysts. The experiment was carried out in a pressurized reactor operated at temperature and pressure up to 350 o C and 30 bar, respectively. The CoMo catalysts used in the experiment were prepared by 10 wt.% loading of cobalt and molybdenum solutions over various supports, i.e. -Al2O3, SiO2, and -Al2O3-SiO2 through impregnation method. It is figured out from the experiment that non-sulfide CoMo based catalysts have functioned well in the hydrocracking conversion of Calophyllum inophyllum kernel oil into fuels, such as gasoline, kerosene, and gasoil. The CoMo/-Al2O3 catalyst resulted higher conversion than CoMo/SiO2 and CoMo/-Al2O3-SiO2. The fuel yields were 25.63% gasoline, 17.31% kerosene, and 38.59% gasoil. The fuels obtained in this research do not contain sulfur compounds so that they can be categorized as environmentally friendly fuels.

Biodiesel can be produced from various vegetable oils and animal fat. Abundant sources of vegetable oil in Indonesia, such as Calophyllum inophyllum, Ricinus communis, palm oil, and waste cooking oil, were used as raw materials. Multi-feedstock biodiesel was used to increase the flexibility operation of biodiesel production. This study was conducted to determine the effect of a combination of vegetable oils on biodiesel characteristics. Degumming and two steps of esterification were applied for high free fatty acid feedstock before trans-esterification in combination with other vegetable oils. Potassium hydroxide was used as a homogenous catalyst and methanol as another raw material. The acid value of C. inophyllum decreased from 54 mg KOH/gr oil to 2.15 mg KOH/gr oil after two steps of esterification. Biodiesel yield from multi-feedstock was 87.926% with a methanol-to-oil molar ratio of 6:1, temperature of 60 ℃, and catalyst of 1%wt.

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Non catalytic transesterification in sub and supercritical methanol have been used to produce biodiesel from palm oil and soybean oil. A kinetic study was done under reaction condition with temperature and time control. The experiments were carried out in a batch type reactor at reaction temperatures from 210 °C (subcritical condition) to 290 °C (the supercritical state) in the interval ranges of temperature of 20 °C and at various molar ratios of oil to methanol. The rate constants of the reaction were determined by employing a simple method, with the overall chemical reaction followed the pseudo-first–order reaction. Based on the results, the rate constants of vegetables oil were significantly influenced by reaction temperature, which were gradually increased at subcritical temperature, but sharply increased in the supercritical state. However, the rate constants of soybean oil were slightly higher than that of palm oil. The activation energy for transesterification of soybean oil was 89.32 and 79.05 kJ/mole for palm oil. Meanwhile, the frequency factor values of both oils were 72462892 and 391210 min-1, respectively. The rate reaction for both of oil were expressed as -rTG = 72462892 exp(-89.32/RT)CTG for soybean oil and -rTG = 391210 exp(-79.05/RT)CTG for palm oil. © 2013 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)