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Design and Biological Applications of Nanostructured Poly(Ethylene Glycol) Films
Published in Tuan Vo-Dinh, Nanotechnology in Biology and Medicine, 2017
Sadhana Sharma, Ketul C. Popat, Tejal A. Desai
Silanization of hydrophilized silicon surface with a reactive end group silane like 3-aminotripropyltrimethoxy silane (APTMS) followed by vapor phase ethylene oxide was used to grow PEG films on silicon-based BioMEMS. APTMS is a bifunctional organosilane possessing a reactive primary amine and a hydrolyzable inorganic trimethoxy group. It binds chemically to both inorganic materials and organic polymers. It is a short-chained silane with a boiling point of 194°C. It violently reacts with water and tends to polymerize on surfaces forming lumps and aggregates. Boron triflouride was used as a gas catalyst with ethylene oxide because it is a weak Lewis acid. PEG composition could be controlled by the concentration of ethylene oxide and the polymerization reaction time. The reaction could be terminated by flowing inert gas over the surface. Figure 24.10 shows the proposed reaction on the silicon surfaces. Three different concentrations of ethylene oxide were used to create 10, 20, and 40 mmol/cm2 surface area of silicon. The reaction was allowed to proceed for 1, 2, and 4 h. The ethylene oxide and boron triflouride ratio of 1:2 was maintained in the reaction chamber. An APTMS concentration of 4 mmol/cm2 surface area of silicon was used.
Recent developments in the greener approaches for the dithioacetalization of carbonyl compounds
Published in Journal of Sulfur Chemistry, 2023
An efficient, facile, and metal-free solid-phase method for the chemoselective dithioacetalization of carbonyl compounds with 1,2-ethanedithiol and 1,3-propanedithiol has been described by Mirjalili et al. [71]. They employed 37% silica-supported boron trifluoride (BF3.SiO2) and nano-silica-supported boron trifluoride (nano-BF3.SiO2) as heterogeneous catalysts for the reactions. A wide range of aliphatic and aromatic aldehydes and ketones bearing both electron-rich and electron-deficient substituents at ortho, meta, or para positions were compatible with the optimized reaction conditions to afford their corresponding 1,3-dithiolanes and 1,3-dithianes in good to excellent yields (80–95%) within 1.5–2.5 min (Scheme 2). These reaction conditions also tolerated the transthioacetalization of acetals and acylals to their corresponding 1,3-dithiolanes and 1,3-dithianes. The unique features of this procedure are the use of silica-supported Lewis acid catalysts and high chemoselectivity for aldehydes in the presence of ketones, ester, acetal, or acylal and the recyclability of the catalysts.
Biodiesel Production from Tannery Waste using a Nano Catalyst (Ferric-Manganese Doped Sulphated Zirconia)
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Vijaya Kumar Booramurthy, Ramesh Kasimani, Sivakumar Pandian
The fatty acid profiles of the fat extracted from tannery waste were characterized by gas chromatography (GC). The instrument consists of an Agilent 7890 Series GC, equipped with HP-INNOWax column and flame ionization detector. Helium was used as a carrier gas with a flow rate of 1 mL min−1. Injector and detector port temperatures were maintained at 240°C and 250°C respectively. The samples required for the GC analysis were prepared by Boron trifluoride-Methanol methylation process. An amount of 1 µL of the sample was injected into the system and the contents were quantified from the integral peak areas of individual fatty acid methyl ester. The instrument was configured with a standard-mixed sample of 37 fatty acid methyl esters (18919-1AMP, FAME Mix) obtained from Sigma-Aldrich Chemicals Pvt. Ltd, Bangalore, India and were used as an internal standard.
Luminescent mesogenic dimeric borondifluoride complexes
Published in Liquid Crystals, 2021
Zih-Yang Lei, Yi-Hong Cai, Gene-Hsiang Leea, Chung K. Lai
4.10.1 BF2 complex of (2Z,2ʹZ)-3,3ʹ-(1,4-phenylenebis(azanediyl))-bis(1-(6-(dodecyloxy) naphthalen-2-yl)prop-2-en-1-one) 2a-BF2 (n = 12): a solution of (2Z,2ʹZ)-3,3ʹ-(1,4-phenylene bis(azanediyl))bis(1-(6-(dodecyloxy)naphthalen-2-yl)prop-2-en-1-one) (0.4 g, 0.48 mmol) dissolved in 200 mL CH2Cl2 was added triethylamine (0.15 g, 1.44 mmol). The mixture was refluxed for 30 minutes and added boron trifluoride diethyl etherate (0.29 mL, 2.5 mmol). The solution was refluxed for 24 h. After reaction, the solution was filtered with filter paper, washed with CH2Cl2 and then concentrated. The products isolated as yellow powder were obtained by recrystallisation from CH2Cl2/hexane. Yield 40%. Anal. Calcd for C56H70B2F4N2O4: C, 72.11; H, 7.56; N, 3.00. Found C, 72.71; H, 7.86; N, 2.95. MS (HRFAB, m/z): calcd for M+: 932.5458. Found: 932.5572.