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2 into Industrial Products
Published in Ashok Kumar, Swati Sharma, 2 Utilization, 2020
Ramya Thangamani, Lakshmanaperumal Vidhya, Sunita Varjani
The oxalic acid is generally produced from oxalate salt; however, it can also be produced under laboratory conditions by the cationic reduction of CO2 in an electrolytic cell. The porous membrane separates the anode and cathode compartments, and the catholyte acts as an organic solvent. The preferred solutes for the catholyte are tetraethylammonium bromide, tetrabutylammonium iodide, tetrabutylammonium perchlorate, tetraethylammonium perchlorate, and tetraethylammonium p-toluenesulfonate. When the anolyte remains the same electrolyte and the solvent as the catholyte, the coulombic yields are as high as 75%. However, close to 97% of sodium oxalate is also obtained when the aqueous solution of sodium salt is used as the anolyte. This process involved in the synthesis of alkali metal salts of glycolic acid, ethylene glycol, alkali metal salts of nitrilotriacetic acid by the hydrogenation of oxalic acid or an alkali metal hydrogen oxalate, alkali metal salts of diglycolic acid and alkali metal salts of glycine may sometimes contain ammonia or otherwise oxalic acid or alkali metal hydrogen oxalate that contains less than two moles of water.
Dermal Uptake
Published in Stephen S. Olin, Exposure to Contaminants in Drinking Water, 2020
Annette L. Bunge, James N. McDougal
Some chemicals found in water are always ions (e.g., paraquat or tetraethylammonium bromide). Other chemicals (weak acids or bases) can exist in either their ionized or unionized form depending on their pH. Still other chemicals are never unionized, but may be uncharged (i.e., zwitterionic or net neutral) at some pH values. For chemicals with one dominant acid-base reaction, the fraction of chemical that is unionized (i.e., fui) can be determined from the acid dissociation constant (i.e., pKa) and the pH of the water in which the chemical is dissolved: () fui=11+10g
2 Utilization
Published in S. Komar Kawatra, Advanced Coal Preparation and Beyond, 2020
Nonaqueous electrolytes for this purpose are based on an organic aprotic solvent phase like dimethylformamide or acetonitrile, and a soluble organic salt such as tetraethylammonium bromide or tetrabutylammonium perchlorate. The reaction can be homogenously catalyzed by the presence of an aromatic nitrile, such as o-tolunitrile (Fischer et al., 1981; Gennaro et al., 1996; Jitaru et al., 1997).
Investigation of surface adsorption and thermodynamic properties of 1-tetradecyl-3-methylimidazolium bromide in the absence and presence of tetrabutylammonium bromide in aqueous medium
Published in Journal of Dispersion Science and Technology, 2022
Harsh Kumar, Gagandeep Kaur, Shweta Sharma
The values of CMC of [C14mim][Br] in the presence of (0, 1, 2, and 5) mM tetrabutylammonium bromide (C4H9)4NBr at different temperatures (298.15, 308.15, and 318.15) K obtained from conductivity measurement can be further compared with those in the presence of (0, 1, 2, and 5) mM tetraethylammonium bromide (C2H5)4NBr at different temperatures (298.15, 308.15, and 318.15) K[44] as reported in Table 3. It can be observed from the table that the addition of both the tetraalkylammonium salts leads to the decrease in value of CMC of [C14mim][Br], but the lowering in the value of CMC is more in case of addition of (C4H9)4NBr as compared to (C2H5)4NBr. This may be due to the fact that the (C4H9)4NBr having longer alkyl chain exhibits stronger hydrophobicity as compared to (C2H5)4NBr, which in turn promotes the aggregation of [C14mim][Br] powerfully leading to more reduction in value of CMC.
Sustainable and rapid production of biofuel γ-valerolactone from biomass-derived levulinate enabled by a fluoride-ionic liquid
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2021
Yan Li, Weibo Wu, Hu Li, Wenfeng Zhao, Song Yang
Initially, the reduction reactions were conducted using PMHS as hydrogen source in the presence of different catalysts (i.e., NH4F, [TEA]F, [TBA]F, [TBA]Cl, [TBA]Br, and [TBA]OH), and the obtained results are shown in Table 1. [TBA]F and [TEA]F were found to have remarkable catalytic activity. In contrast, [TBA]Cl, [TBA]Br and [TBA]OH were not active at all for the reduction. It can be concluded that F− might be the active sites (Zhao et al, 2017a). However, NH4F showed no activity, indicating that different cations may influence the catalyst activity because of variable cationic sizes. As the size of cations decreased, the activity of tetraalkylammonium fluoride-catalyzed activity declined, where a larger cation size might correspond to the relatively high solubility of ILs (Clark 1980). It is clear to see that the cationic volume of tetrabutylammonium is larger than that of tetraethylammonium and ammonium cations (Wright, Hageman, and McClure 1994). Accordingly, when [TBA]F was used as a catalyst, a 99% conversion of EL and an 85% yield of GVL could be obtained. Besides, the turnover frequency (TOF) was 52 h−1 in 0.5 h, indicating that relatively higher nucleophilicity and solubility of fluoride can accelerate the conversion of EL to GVL.
Methods for the direct synthesis of thioesters from aldehydes: a focus review
Published in Journal of Sulfur Chemistry, 2020
Noor H. Jabarullah, Kittisak Jermsittiparsert, Pavel A. Melnikov, Andino Maseleno, Akram Hosseinian, Esmail Vessally
Almost simultaneously, Zhu and co-workers reported a convenient metal-free cross-dehydrogenative coupling of a diverse set of aldehydes 19 with thiols 20 using tetraethylammonium bromide (TEAB) as an efficient homogeneous catalyst in DCE under an inert atmosphere [44]. Among the various common oxidants like tBuOOH, TBHP, H2O2, K2S2O8, PhI(OAc)2, ozone; K2S2O8 was the most efficient for this transformation. Under the optimized reaction conditions, various aliphatic, aromatic, and heteroaromatic aldehydes were tolerated well and gave the desired thioesters 21 in good to excellent yields (Scheme 8). However, 3-pyridinecarboxaldehyde failed to produce any product. According to the authors proposed mechanism (Scheme 9), this reaction starts with the generation of the tetraethylammonium sulfate radical anion via the interaction of K2S2O8 with Et4NBr. Next, the reaction of this radical with the aldehyde 19 and the thiol 20 affords an acyl radical A and a thiyl radical B. Finally, cross-coupling of the radicals A with B leads to the formation of the expected thioester 21.