Synthesis of Polyhedral Magnetite Particles by Hydrothermal Process Under High Pressure Condition

Magnetite particles were successfully generated by hydrothermal synthesis using water at subcritical conditions. By changing the temperature and pressure at subcritical water conditions, the thermodynamics and transport properties of the water can be controlled, thus enabling to manage the way of crystal formation, morphology, and particle size. In this work, the experiments were carried out at temperatures of 250 °C and 290 °C and a pressure of 10 MPa with a reactor made of SUS 316 in a batch system. The synthesized particles were dried in vacuum condition and characterized by SEM and XRD. The XRD patterns showed that magnetite particles were dominantly formed in the particle products with a black color. The results showed that the magnetite particles formed had diameters of around 60 nm in all experiments with irregular polyhedral shaped morphologies

Centrifugal melt spinning of polyvinylpyrrolidone (PVP)/triacontene copolymer fibres

Polyvinylpyrrolidone/1-triacontene (PVP/TA) copolymer fibre webs produced by centrifugal melt spinning were studied to determine the influence of jet rotation speed on morphology and internal structure as well as their potential utility as adsorbent capture media for disperse dye effluents. Fibres were produced at 72 C with jet head rotation speeds from 7000 to 15,000 r min-1. The fibres were characterised by means of SEM, XRD and DSC. Adsorption behaviour was investigated by means of an isothermal bottle point adsorption study using a commercial disperse dye, Dianix AC-E. Through centrifugal spinning nanofibers and microfibers could be produced with individual fibres as fine as 200–300 nm and mean fibre diameters of ca. 1–2 lm. The PVP/TA fibres were mechanically brittle with characteristic brittle tensile fracture regions observed at the fibre ends. DSC and XRD analyses suggested that this brittleness was linked to the graft chain crystallisation where the PVP/TA was in the form of a radial brush copolymer. In this structure, the triacontene branches interlock and form small lateral crystals around an amorphous backbone. As an adsorbent, the PVP/TA fibres were found to adsorb 35.4 mg g-1 compared to a benchmark figure of 30.0 mg g-1 for a granular-activated carbon adsorbent under the same application conditions. PVP/TA is highly hydrophobic and adsorbs disperse dyes through the strong ‘‘hydrophobic bonding’’ interaction. Such fibrous assemblies may have applications in the targeted adsorption and separation of non-polar species from aqueous or polar environments

Transesterification of Vegetables oil using Sub-and Supercritical Methanol

A benign process, non catalytic transesterification in sub and supercritical methanol method was used to prepare biodiesel from vegetables oil. The experiment was carried out in batch type reactor (8.8 ml capacity, stainless steel, AKICO, JAPAN) by changing the reaction condition such as reaction temperature (from 210°C in subcritical condition to 290°C in supercritical state in ranges of 20°C), molar ratio oil to methanol (1:12-1:42) and time of reaction (10-90 min). The fatty acid methyl esters (FAMEs) content was analyzed by gas chromatography-flame ionization detector (GC-FID). Such analysis can be used to determine the biodiesel yield of the transesterification. The results showed that the yield of biodiesel increases gradually with the increasing of reaction time at subcritical state (210-230oC). However, it was drastically increased at the supercritical state (270-290oC). Similarly with the influence of molar ratio oil-methanol, yield biodiesel sharply increased with increasing ratio molar of oil-methanol up to 1:24. The maximum yield 86 and 88% were achieved for soybean oil and palm oil, respectively, at 290oC, 90 min of reaction time and molar ratio of oil to methanol 1:24

Non Catalytic Transesterification of Vegetables Oil to Biodiesel in Sub-and Supercritical Methanol: A Kinetic’s Study

<p>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 BCREC UNDIP. All rights reserved</p><p><em>Received: 18th October 2012; Revised: 14th December 2012; Accepted: 16th December 2012</em></p><p>[<strong>How to Cite</strong>: N.P. Asri, S. Machmudah, W. Wahyudiono, S. Suprapto, K. Budikarjono, A. Roesyadi, M. Goto, (2013). Non Catalytic Transesterification of Vegetables Oil to Biodiesel in Sub-and Supercritical Methanol: A Kinetic’s Study. <em>Bulletin of Chemical Reaction Engineering &amp; Catalysis</em>, 7 (3): 215-223. (doi:10.9767/bcrec.7.3.4060.215-223)]</p><p>[<strong>Permalink/DOI</strong>: <a href="http://dx.doi.org/10.9767/bcrec.7.3.4060.215-223">http://dx.doi.org/10.9767/bcrec.7.3.4060.215-223</a> ]</p><p><a href="http://www.scopus.com/inward/citedby.url?scp=84875901221&amp;partnerID=65&amp;md5=5c6404626948d1b3337738ce80c45f21" target="_blank"><img src="http://searchapi.scopus.com/citedby?&amp;citedbycount=http://be-layer7-prod/content/abstract/citation-count?scopus_id=84875901221&amp;authToken=sat_9746B6CF99D4F220A410868C1FAE9EF71DEE3AB29B68FFE289A36D991160BCE942A986562DAA550D9A2604848D8FED65468012018BC0DED56F060743AB793CAD70AE43AB2EBD91373DF6398C938E4AD64131C96ABE27414FBC6D4AE3B0DE29D715483579D779CDC533EDC62374F0B03E940CE48E068449F53C30F99B01D580BF9C67D9078468936603E43FC8D5092A89FCB1A642D41296BCBD78F66992BDA9434536D281F3EC82E3B1731CC919B4B7B5&amp;ipAddress=182.255.2.3&amp;contentAPIKey=9cf02f45d6c541820cab5d2cd870c4f6&amp;authTokenStatusCode=200" border="0" alt="" /></a> <a class="noDeco" href="http://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&amp;scp=84875901221" target="_blank">View in <img style="vertical-align: bottom;" src="http://searchapi.scopus.com/images/scopus_grey_new.gif" border="0" alt="" /></a> | <a title="Add this article to your Mendeley library" href="http://www.mendeley.com/import/?url=http://dx.doi.org/10.9767/bcrec.7.3.4060.215-223"><img src="http://www.mendeley.com/graphics/mendeley.png" alt="" /></a></p