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Extraction of Algal Neutral Lipids for Biofuel Production
Published in Ozcan Konur, Biodiesel Fuels Based on Edible and Nonedible Feedstocks, Wastes, and Algae, 2021
Saravanan Krishnan, Jaison Jeevanandam, Caleb Acquah, Michael K. Danquah
In this method, a 1: 2 volume ratio of methanol-chloroform is utilized to retrieve lipids from endogenous cells. The mixture of alcohol and chloroform will lead to two phases during extraction; the lipids will be present in the upper phase (Folch et al., 1957). Jones et al. (2012) evaluated the efficiency of the Folch method in extracting total lipids from salt water Chlorella KAS603 algae. Two hundred mg of a concentrated pellet of algae was subjected to disruption in a methanol-chloroform solution at an optimized volume via a Dounce homogenizer. The study emphasized that the method is highly beneficial in extracting various significant lipids from the algae compared to other methods. However, ‘high-performance liquid chromatography’ (HPLC) analysis showed that the Folch method yielded a lower concentration of TAGs and hydrocarbon which are required for biofuel production. Further, the study also recommended that 2-ethoxyethanol would be beneficial as an alcohol solvent for lipid extraction via the Folch approach, instead of methanol (Jones et al., 2012).
Chemistry of the Poly(alkylene oxide)s
Published in F. E. Bailey, Joseph V. Koleske, Alkylene Oxides and Their Polymers, 2020
F. E. Bailey, Joseph V. Koleske
Poly(ethylene oxide) can also be degraded by mechanical action such as high shearing forces, with both shear level and duration of shearing force being important variables (129-132). As molecular weight increases, the effect is markedly more noticeable. Even the low shear forces encountered in capillary viscometry can have an effect and cause errors to arise in determination of specific viscosity (133). Shear degradation can cause pronounced broadening of the molecular weight distribution and can preclude use of gel permeation chromatography as an investigative tool. In certain solvents, such as tetrahydrofuran, large differences in intrinsic viscosity (12.4 to 1.7 dl/g) have been noted with relatively, but markedly, smaller changes in other solvents such as 50/50 by volume water/ethanol mixtures (134). Other investigators have had good results when 2-ethoxyethanol at 80°C was used as the elution solvent (135). Investigations of photoirradiation in deaerated systems led to degradation with the formation of methane, ethane, and carbon dioxide under acidic conditions and of hydrogen under basic or neutral condtions (136). Methods of improving stability by polymerization-catalyst selection have been studied (137). The stages of autooxidationhave also been under investigation (138). Thermal decomposition of polyoxyethylene along and in combination with methyl methacrylate is another interesting way to examine the degradation of polyoxyethylene and other polyethers (139,140).
Biopolymers as Supports for Heterogeneous Catalysis: Focus on Chitosan, a Promising Aminopolysaccharide
Published in Arup K. SenGupta, Ion Exchange and Solvent Extraction, 2007
Eric Guibal, Thierry Vincent, Francisco Peirano Blondet
Zhu et al. described the synthesis of different dimethylaminoethyl derivatives of chitosan for the immobilization of Rh cluster, and the reduction of nitrobenzene and benzaldehyde.380,381 Instead of molecular hydrogen, water is used as the hydrogen supply for this water–gas shift reaction. Benzaldehyde is transformed to benzyl alcohol with a maximum yield obtained at 80°C, and its conversion rate increases with the amount of catalyst. The solvent has a large impact on the conversion: 2-ethoxyethanol is much more efficient than toluene. Under optimum conditions (2-ethoxyethanol, T: 80°C), benzaldehyde conversion exceeds 96%. Nitrobenzene is converted to aniline with yield of 70% in 2-ethoxyethanol solvent (which is more appropriate than toluene).
Cleaning workers’ exposure to volatile organic compounds and particulate matter during floor polish removal and reapplication
Published in Journal of Occupational and Environmental Hygiene, 2019
Joonas Ruokolainen, Marko Hyttinen
Glycol ethers are widely used in different chemicals, for example, in paints, lacquers, cleaning solutions (especially floor polishes and polish removers), degreasers, varnish removers, and hydraulic fluids.[4,10–13] Due to the vast use of glycol ethers there are multiple occupations where exposure to glycol ethers occurs, for example, painters, printers (silk-screen, offset, and stamping printers), cleaning workers, graffiti removers, textile and dying industry, workers handling fuel.[4,13,14] Repeated exposure to glycol ethers can lead to contact dermatitis.[13] Previously used glycol ethers (2-alkoxyethanols, mainly 2-methoxyethanol and 2-ethoxyethanol) were found to cause multiple adverse health effects, including hematological effects, oligospermia and azoospermia, reproductive problems, and immunotoxic effects, therefore they have been substituted with less hazardous solvents with redesigned chemical structures.[10] The exposure to gaseous EGBE can cause irritation of eyes, nose, and throat.[12] Also, EGBE has hematological effects, for example, it has been linked to reticulocytosis in screen-printing workers.[12,15] A study by Rella et al.[16] indicated that cleaning related EGBE caused complaints of poor indoor air quality. EGPE has been reported causing contact urticarial.[17,18]