China
Africa
Explore chapters and articles related to this topic
Homogeneous Methane Functionalization
Published in Jianli Hu, Dushyant Shekhawat, Direct Natural Gas Conversion to Value-Added Chemicals, 2020
Anjaneyulu Koppaka, Niles Jensen Gunsalus, Roy A. Periana
In this classification, the stoichiometric oxidants used for the CHA of methane are O2-regenerable. Very few systems that can be classified under this category have been reported. The stoichiometric reaction of methane with HgII(CF3SO3)2, mercuric triflate, in nonoxidizing triflic acid to generate near quantitative yields of CF3SO3CH3, methyl triflate, and the reduced mercurous triflate, Hg2(CF3SO3)2 falls in this category (Periana et al.1993). This is an O2-regenerable system as the HgII/Hg0 couple (Eo ~ 0.9 V) (HgII/HgI couple (Eo ~ 0.91 V)) can be reoxidized by O2 (Eo = 1.2 V). In this stoichiometric CHA system, CH3–HgII intermediate was generated by the direct reaction of Hg(II) with methane. The intermediate then functionalizes to yield methyl triflate. This system was also made catalytic by replacing triflic acid with oxidizing concentrated H2SO4. As shown in Equation (12.4), Hg(II) system has the potential to further develop into a system where the reaction can be carried out in a compatible inert, aprotic solvent medium by utilizing the acids being released during the reaction. However, the toxicity of mercury may hamper the further development of these stoichiometric systems into commercial process.
Chemistry of Photoresist Materials
Published in Bruce W. Smith, Kazuaki Suzuki, Microlithography, 2020
Takumi Ueno, Robert D. Allen, James Thackeray
Initially, all 193 nm resists used triflic acid photoacid generators. Whereas DUV resists had significant, controllable unexposed film loss, most 193 nm materials had no dark erosion (no unexposed thinning). Additionally, early 193 nm resists had two characteristics: methacrylate polymers with no unexposed thinning and high-activation protecting groups. Workers at IBM [225] first established the importance of nonvolatile, low-diffusible PAGs in 193 nm resists. Higher–molecular weight perfluoroalkyl sulfonates (e.g., perfluorobutyl sulfonate) were shown to dramatically reduce volatility, improve resolution, and allow higher bake temperatures than triflic acid–containing PAGs. The volatility of triflic acid was shown to cause T-topping and webbing in nonthinning high-activation (high-bake) resists. This observation leads to breakthrough resolution, with high-quality 150 nm features being produced in etch-resistant methacrylate polymers (IBM Version 2 resists). Higher–molecular weight perfluoroalkyl photoacids of this type are in use today for high-resolution resist applications. Figure 7.63 shows the consequence of photoacid volatility on resist imaging, and Figure 7.64 shows clear image patterns without T-tops.
*
Published in Eli Ruckenstein, Hangquan Li, Chong Cheng, Solution and Surface Polymerization, 2019
We have previously demonstrated that aniline can be bound to a SAM monolayer generating functional groups which allow the further grafting of polyaniline (PANI). The goal of the present paper is (a) to employ a SAM monolayer of phenylsilane generated by reacting phenyltrichlorosilane with the OH groups of a silicon surface, which are obtained by treating the surface with a “piranha” solution (a mixture of a concentrated sulfuric acid solution and a hydrogen peroxide solution), (b) to pattern this monolayer using an UV laser, (c) to dearylate the phenylsilane by its reaction with HOTf and formation of a weak bond between the latter acid and silane, (d) to substitute the –OTf group of the triflic acid with aniline, and finally (e) to graft polymerize aniline to the aniline-primed surface. In essence, a patterned PANI will be prepared through the combination of a chemical graft polymerization and patterned SAM technique. With the advent of nanolithography, such as the AFM lithography, this method can provide nanometer size features for patterns of conductive polymers.
Activity and stability of amino-functionalized SBA-15 immobilized 12-tungstophosphoric acid in the oxidative desulfurization of a diesel fuel model with H2O2
Published in Chemical Engineering Communications, 2019
H2N-SBA-15 material was acidified by triflic acid, according to the following procedure (Yuan and Chen, 2011): 50 mL of suspension solution containing 1 g of H2N-SBA-15 in acetonitrile solvent was mixed with 4 mL of 0.05 M triflic acid. The mixture was then refluxed at 80 °C for 5 h. Acidified H3N+-SBA-15 was obtained by washing and filtering the solid three times with acetonitrile to remove any remaining triflic acid. The tungstophosphoric acid (HPW) was immobilized on H3N+-SBA-15 support by adding 0.3 g of tungstophosphoric acid into 50 mL methanol solvent containing 1 g of H3N+-SBA-15. After refluxing at 65 °C for 5 h, the solid product was filtered, separated by methanol solvent, and then dried at 100 °C overnight to yield the 21% PW–-H3N+-SBA-15 catalyst.
Structural and spectroscopic features of proton hydrates in the crystalline state. Solid-state DFT study on HCl and triflic acid hydrates
Published in Molecular Physics, 2018
M. V. Vener, I. Yu. Chernyshov, A. A. Rykounov, A. Filarowski
In the present study, eight molecular crystals are considered (Tables S1–S4): H3O+Cl− [57,58], H5O+2Cl− [59], H7O+3Cl− [60], H9O4+Cl−•2H2O [61], H3O+CF3SO3− [62], H5O+2CF3SO3− [63], H7O+3NO3− [64] and H9O4+CF3SO3− [65]. These crystals are selected for the following reasons: (1) they consist of the particular protonated water cation and small/polyatomic anion (Figures 1–3); (2) experimental IR spectra of some crystals under consideration are available [66–69]. Crystalline trihydrate of the triflic acid is absent in Inorganic Crystal Structure Database [70] and Cambridge Structural Database [71]. Therefore, the H7O+3NO3− crystal was considered in the present study.
A review on synthetic investigation for quinoline- recent green approaches
Published in Green Chemistry Letters and Reviews, 2022
Ashish Patel, Stuti Patel, Meshwa Mehta, Yug Patel, Rushi Patel, Drashti Shah, Darshini Patel, Umang Shah, Mehul Patel, Swayamprakash Patel, Nilay Solanki, Tushar Bambharoliya, Sandip Patel, Afzal Nagani, Harnisha Patel, Jitendra Vaghasiya, Hirak Shah, Bijal Prajapati, Mrudangsinh Rathod, Bhargav Bhimani, Riddhisiddhi Patel, Vashisth Bhavsar, Brijesh Rakholiya, Maitri Patel, Prexa Patel
Wu et al. have discovered a one-pot synthesis of regioselective copper(II)-catalyzed annulation of anilines with two molecules of alkyne esters to form substituted quinolines using copper triflate [Cu(OTf)2] as a catalyst and triflic acid [HOTf] as an add-on system in acetonitrile at 120°C for 24 h to obtain 56–98% yields (Scheme 83) (121).