China 
Africa 
Explore chapters and articles related to this topic
Five-Membered Fused Polyheterocycles
Published in Navjeet Kaur, Metals and Non-Metals, 2020
Roesch et al. [99–100] studied the synthesis of isoindole[2,1-a]-indoles via annulation of internal alkynes by imines derived from o-iodoanilines (Scheme 36), as an extension of palladium-catalyzed annulation of o-iodoanilines and o-iodoanilides with internal alkynes to indoles. Indoles were formed by the cyclization of o-halo N-allylanilines when treated with tetrabutylammonium chloride, Pd(OAc)2 and a base in dimethylformamide [101]. The same cyclization also occurred with o-halo-N-vinylanilines [102–103]. In another such study, Larock and Yum [104] reported the reaction of imines with 2 eq. of internal alkynes, expecting the formation of quinolines. However, quinolines were not formed, but isoindoloindoles could be isolated in good yields (50–80%) under the conditions used in the earlier annulation reaction. Internal alkynes possessing either a heterocyclic ring or a phenyl have been used in this annulation reaction [81, 93].
Direct (Hetero)Arylation Polymerization for the Preparation of Conjugated Polymers
Published in John R. Reynolds, Barry C. Thompson, Terje A. Skotheim, Conjugated Polymers, 2019
J. Terence Blaskovits, Mario Leclerc
The first copolymer synthesized by DHAP used a mixed solvent (DMF/H2O) system. However, later studies which reported obtaining P3HT with very high RR and molecular weight using dry solvents in inert conditions and at high temperature began a trend of performing DHAP in completely anhydrous and pressurized conditions (a superheated solvent is a closed flask).85,91 This was considered to be a necessity to ensure the proper functioning of the catalytic system until recently, when biphasic conditions (toluene/H2O) were used to prepare a wide range of donor-acceptor copolymers with results comparable to or better than those in anhydrous and air-free conditions (Figure 5.18).167 This approach bears a number of advantages. Most notably, it removes the need for dry solvents and an inert atmosphere as well as increases the accessibility of the base due to the increased solubility of many carbonate salts in water. As the growing polymer chain is only soluble in the organic phase, the reaction occurs at the liquid-liquid interface. In order to favor this, a phase transfer agent was also added, in a similar fashion to the Miyaura–Suzuki cross-coupling reaction. Results were dependent on the nature of the phase transfer agent: tetrabutylammonium chloride provided better results than the bromide analog. Also similar to Miyaura–Suzuki protocols was an observation that debromination occurs more readily in biphasic conditions. This could be explained by the greater availability of protons (from water) than in pure organic solvents.
Water Stability Studies on Hydrophobic Deep Eutectic Solvents and Extractive Desulfurization of Fuel
Published in Papu Kumar Naik, Nikhil Kumar, Nabendu Paul, Tamal Banerjee, Deep Eutectic Solvents in Liquid–Liquid Extraction, 2023
Papu Kumar Naik, Nikhil Kumar, Nabendu Paul, Tamal Banerjee
The present chapter exemplifies the molecular-level understanding of the stability of hydrophobic DESs in water at a temperature of 298.15 K and 1 atm atmospheric pressure. Here, the MD simulation study is carried out for the stability of (a) DL-menthol–organic acid-based DESs and (b) tetrabutylammonium chloride-organic acid-based DESs in aqueous solutions. The composition of each system considered in the simulation work is kept identical to that of the experimental work of Florindo et al. [3] The ensuing section starts with the computational details and thereafter discusses the evaluation of nonbonded interaction. Furthermore, the radial and combined distribution functions (RDFs and CDFs, respectively) between the different components of the DES and water, spatial distribution function (SDF), mean square displacement (MSD), and self-diffusivity analysis, among others, are evaluated. The ‘relative stability factor’ is introduced as a new means for measuring the stability of a DES in contact with water. Hydrogen bonding analysis of the DES systems has been carried out to get valuable insights into the DES interactions. To manage the extraction of the target molecules from sulfur-contaminated liquid fuels, quantum mechanical (QM) simulations are used to get a molecular-level knowledge of how certain components inside traditional DESs interact with model aromatic sulfur compounds (ASCs). DESs containing 1:2 molar ratios of choline chloride:urea (reline) and choline chloride:EG (ethaline) were studied in detail, as were the model ASCs benzothiophene (BT) and dibenzothiophene (DBT), and the sulfoxide/sulfone oxidation products oxides and dioxides of BT and DBT.
Anion-templated silver nanoclusters: precise synthesis and geometric structure
Published in Science and Technology of Advanced Materials, 2023
Yusuke Horita, Mai Ishimi, Yuichi Negishi
There are numerous reports on X@Ag8 NCs with a diverse range of central anions, including fluoride ions (F–), Cl–, and bromide ions (Br–). All these X@Ag8 NCs have been synthesized by Liu and colleagues. They reported the syntheses of 2 (F@Ag8a), 3 (F@Ag8b), 4 (Cl@Ag8a), 5 (Cl@Ag8b), 6 (Cl@Ag8c), 7 (Cl@Ag8d), 8 (Cl@Ag8e), 9 (Br@Ag8a), 10 (Br@Ag8b), 11 (Br@Ag8c), and 12 (Br@Ag8d) from 2004 to 2014 [131–133]. All of these X@Ag8 NCs were synthesized using the stirring method. For the precursors of each X, tetrabutylammonium fluoride (Bu4NF), tetrabutylammonium chloride (Bu4NCl), tetrabutylammonium bromide (Bu4NBr), benzyltriethylammonium chloride ((PhCH2)Et3NCl), or tetraphenylphosphonium bromide (PPh4Br) were used, and the central X anion is formed by their dissociation in the reaction process.
Interface engineering of quaternary ammonium phosphotungstate for efficient oxidative desulfurization of high-sulfur petroleum coke
Published in Petroleum Science and Technology, 2023
Jiahong Gong, Huanhuan Xu, Jixing Liu, Hui Liu, Mingqing Hua, Ning Yang, Peiwen Wu, Huaming Li, Wenshuai Zhu
At room temperature, 0.01 mol of tetrabutylammonium chloride was dissolved in 50 mL water. Then 50 mL 0.06 mol·L−1 phosphotungstic acid (H3PW12O40) aqueous solution was added into it. After stirring for 12 h, a white precipitate was formed, which was filtered and washed with deionized water until there was no chloride ion in the filtrate. Then, the obtained solid was dried at 80 °C for 24 h to obtain C4@HPA. Tetrabutylammonium chloride was replaced with octadecyltrimethylammonium chloride, dodecyltrimethylammonium chloride and hexadecyltrimethylammonium chloride, respectively. By operating in the same way, four alkyl quaternary ammonium phosphotungstate ionic liquids were gained with different carbon chain lengths, abbreviated as Cn@HPA (n = 4, 8, 12, 16).
Science of 2.5 dimensional materials: paradigm shift of materials science toward future social innovation
Published in Science and Technology of Advanced Materials, 2022
Hiroki Ago, Susumu Okada, Yasumitsu Miyata, Kazunari Matsuda, Mikito Koshino, Kosei Ueno, Kosuke Nagashio
The use of 2D nanospace is not limited to BLG and FLG. For example, Li et al. proposed ‘imprinting’ ferromagnetism by intercalating magnetic metals into layered TaS2 (Figure 7(i)) [89]. Given that tetrabutylammonium chloride (TBAC) can be intercalated into a TaS2 crystal, they facilitated the cointercalation of Co ions into TaS2 layers by dissolving CoCl2 in the TBAC solution. This allowed the experimental observation of the magnetic properties of the Co-intercalated TaS2. An electrochemical method has also been used to intercalate molecules into MoS2 layers [90]. Interestingly, the intercalation of cetyltrimethylammonium bromide (CTAB) induced the phase transition of MoS2 from the semiconducting 2 H phase to the semimetallic 1T phase; these are examples where both the intercalant and the host 2D material offer unique physical and chemical properties.