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Assessing Interactions of Microalgae in Synthesizing Nanoparticles
Published in Pradipta Ranjan Rauta, Yugal Kishore Mohanta, Debasis Nayak, Nanotechnology in Biology and Medicine, 2019
Manoj Kumar Enamala, Azzuliani Binti Supangat, Chandrashekar Kuppam, Sudhakar Reddy Pamanji, Murthy Chavali, Maria P. Nikolova
In the normal transesterification of fatty acids from algal oil, sodium methoxide or an acidic or basic compound is used as a catalyst for increasing the speed of the reaction. Catalysts are now replaced with the nanospheres, where these nanospheres are loaded with the acidic or basic catalysts to react with the free fatty acids. The advantages of using nanospheres as a replacement to the normal chemical catalysts are that it eliminates various steps like water washes, separations, acid neutralization, etc. Normal catalysts cannot be used again and again, but nanospheres which are loaded with catalysts can be. Overall, this economical, recyclable method produces cleaner biodiesel, reduces water consumption, and has a great impact on the various environmental factors (Sap and Demmers, 2016).
Mineral Resources, Pollution Control, and Nanotechnology
Published in Stephen L. Gillett, Nanotechnology and the Resource Fallacy, 2018
Indeed, the direct synthesis of organic silicates—that is, silicon bonded directly to organic side groups—from minerals has been demonstrated, of alkoxides in particular.104 An “ alkoxide” can be visualized as compound of an alcohol with a metal, with the hydrogen in the −OH group of the alcohol replaced by a metal atom. Tetraethoxysilane (called tetraethyl silicate in the older literature), for example, with formula Si (OC2H5), consists of a silicon atom bonded to four ethoxy groups, which can be formally derived from ethanol (C2H5OH) by omitting the hydrogen on the -OH group. Furthermore, the resulting alkoxides largely reflect the structure of the original silicate anion; hence, the syntheses also provide unexpected control over the products obtained. In particular, a complex chain siloxane was synthesized directly from K2CuSi4O10, a “tube” chain silicate, with preservation of the intricate tubular silicate backbone. 105 Alkoxides are reactive compounds and so again are useful feedstocks for further syntheses. They can be used directly in sol-gel synthesis, for example, or further reduced to siloxanes. Sodium methoxide is used in the conventional synthesis of biodiesel (Box 5.12).
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Published in Ozcan Konur, Bioenergy and Biofuels, 2017
Homogeneous and heterogeneous acids and bases, lipases, and sugars, as well as ion exchange resins and zeolites with acidic or basic functionalities catalyze transesterification (Akoh et al., 2007; Di Serio et al., 2008; Narasimharao et al., 2007; Van Gerpen, 2005). Industrial production of biodiesel most commonly utilizes sodium hydroxide, potassium hydroxide, or sodium methoxide, with the latter preferred because it cannot form water upon reaction with alcohol such as with hydroxides. Transesterification with bases is 4000 times faster and more complete than with mineral acid catalysts (Di Serio et al., 2008). Furthermore, alkaline catalysis is performed at lower temperatures and pressures and is less corrosive to industrial equipment than acid catalysis (Freedman et al., 1984; Lotero et al., 2005; Van Gerpen, 2005). However, alkaline catalysts require anhydrous feedstocks with low FFAs, otherwise hydrolysis, soap formation, and catalyst deactivation become problematic (Figure 4.2). In fact, acids can simultaneously catalyze esterification of FFAs and transesterification of TAGs (Haas et al., 2003; Lotero et al., 2005).
Influence of irradiation and addition of antioxidants on the oxidation stability of Jatropha, Pongamia and Tectona Grandis biodiesels
Published in International Journal of Ambient Energy, 2022
Meetu Singh, Neerja Sharma, Amit Sarin, Sujeet Kesharvani, Chandrabhushan Tiwari, Tikendra Nath Verma, Gaurav Dwivedi
Jatropha, Pongamia and Tectona Grandi's oils have been used for the synthesis of biodiesels through the base-catalysed transesterification method due to their low acid value. During the synthesis of biodiesel, a triglyceride (oil) reacts with an alcohol (methanol) in the presence of a catalyst (Sodium Methoxide) followed by the separation process. Methanol (1:6 M ratio to oil) was separately added to the sodium methoxide as catalyst (0.75 wt% of oil) and stirred until the complete dissolution of catalyst in methanol in a water bath shaker as shown in Figure 2. The above solution was added to respective oils in the reactor maintained at 65°C and stirring of this mixture was carried out for 1 h at 400 rpm. After completion of the reaction, the material was transferred to a separating funnel and kept overnight to settle down, which results in the formation of two phases. The upper phase was methyl esters (biodiesels) and the lower part was glycerin. Biodiesels were then washed with warm water four to five times to remove the traces of glycerin, unreacted catalyst and soap formed during the transesterification (KoohiKamali, Tan, and Ling 2012).
Influence of n-butanol on combustion phenomenon of a compression ignition engine fuelled with methyl esters of cottonseed and algal oil
Published in Biofuels, 2021
V. Hariram, J. Godwin John, S. Seralathan, T. Micha Premkumar
The bio-oil as shown in Figure 1(a) was converted into methyl ester by a single-stage transesterification method. The oil was tested for its acid value to verify which method should be used. Using a titration method, the acid value was found to be less than 2%. Hence, a base-catalysed transesterification method was used. The reaction was carried out by first preparing a sodium methoxide solution, by mixing methanol with sodium hydroxide. The prepared mixture was agitated with the bio-oil in an 8:1 molar ratio. The solution was heated to 65–75 °C and agitated at 400 rpm. This solution was then kept in a separating funnel for 48 hours and the glycerol was separated with a visible ring formation at the top. This base-catalysed transesterification of bio-oil yielded around 94% algal oil methyl ester.
Purification of biodiesel by dry washing and the use of starch and cellulose as natural adsorbents: Part II – study of purification times
Published in Biofuels, 2021
Michelle Garcia Gomes, Douglas Queiroz Santos, Luis Carlos de Morais, Daniel Pasquini
The biodiesel employed in this study was obtained from commercial sunflower oil (LIZA) by alkaline transesterification via methylation. With this method, 20% methanol (v/v) and 0.6% NaOH (w/v) were employed as catalysts for the reaction. Initially, sodium methoxide was obtained by mixing methanol and sodium hydroxide under constant agitation until complete homogenisation. Then, the sodium methoxide was added to the sunflower oil, and the mixture was kept under constant stirring for 30 min at 60 °C. After the reaction, the mixture was transferred to a separatory funnel to separate the phases (Figure 1a). After resting, we observed two distinct phases: one containing esters, which was less dense and lighter in colour, and the other rich in glycerin, which was denser and darker in colour (Figure 1b). After standing for 24 h, glycerin was removed and the resulting biodiesel was tested with the different purification processes described in this study [2, 8, 34, 35].