Optimized structures and proton affinities of fluorinated dimethyl ethers Download PDF EPUB FB2
ELSEVIER Journal of Molecular Structure (Theochem) () THEO CHEM Optimized structures and proton affinities of fluorinated dimethyl ethers: an ab initio study Victoria B. Orgel'1, David W.
Ball3'*, Michael J. Zehe11 ^Department Cited by: 6. Optimized structures and proton affinities of fluorinated dimethyl ethers (OCoLC) Microfiche version: Orgel, Victoria B. Optimized structures and proton affinities of fluorinated dimethyl ethers (OCoLC) Material Type: Document, Government publication, National government publication, Internet resource: Document Type.
Optimized Structures and Proton Affinities of Fluorinated Dimethyl Ethers: An Ab Initio Study The proton affinity calculated for (CH3)2O was 7 Kjoule/mole from the experimental value, within the desired variance of +/- 8Kjoule/mole for G2 theory, suggesting that the methodology used in this study is adequate for energy difference.
Quantum chemical calculations using density functional theory with the hybrid B3LYP functional and the ++G(d,p) basis set were performed to determine the conformation of fluorinated ethers (CF(n H 3– n) 2 O) with n F = 1 to n F = 6 and to evaluate the proton affinities of the O atoms and the deprotonation enthalpies of the CH ric as well as asymmetric substituted ethers Cited by: This effect is in good agreement with theoretical data on the complexes between fluorinated dimethyl ethers and water and seems to depend on the number of F atoms implanted on the ether molecule.
View. Assignments of each proton and carbon were assisted by the two-dimensional NMR spectra, as shown in Fig. 3, and these spectra agreed well with the proposed molecular structure of 3. In the 1 H NMR spectrum, the primary aromatic amine protons appeared at ppm and the protons in the aromatic rings (H a to H e) appeared at – ppm.
We suggest, therefore, that the current methodology is acceptable for estimating the proton affinities of partially- and fully-fluorinated methyl (Ref. 10) and ethyl (Ref. 11) ethers. We further submit that any conclusions about the chemistry of fluoroether polymer lubricants based on their basicity can also be predicted reliably with such.
Optimized structures and proton affinities of fluorinated dimethyl ethers: an ab initio study. Journal of Molecular Structure: THEOCHEM(3), DOI: /S(96) Ping Li, L.M. Ng, Jim Liang. HF/G** level. The thermodynamic proton affinity of a compound A is defined as the negative of the enthalpy change, −∆ rH, for the following gas-phase reaction at standard conditions (usually at K under a pressure of × Pa).
A + H+ → AH (1) Theoretically, the proton affinities. Optimized structures and proton affinities of fluorinated dimethyl ethers: an ab initio study. Journal of Molecular Structure: THEOCHEM(3), synthesis of these partially fluorinated ethers by alkylating fluorinated alkoxides generated in situ by treating short or long chain fluorinated acyl chlorides with potassium fluoride.
Results and Discussion 1. Dimethyl sulfate as the alkylating agent Dimethyl sulfate is a powerful alkylating agent and has been used for the methylation of almost.
ﬂuoroalkyl vinyl ether that contains oxygen. R f is a per-ﬂuoroalkyl group of C 1eC 4. PCTFE () ETFE () FEP () PFA () PVF () PVDF () AF () ECTFE () Perfluorinated Partially Fluorinated First melt-processible perfluoropolymer Properties similar to PTFE PTFE () Figure Evolution of ﬂuoropolymer.
Abstract. Fluorinated surfactants have been commercially available since the s. The first available were perfluoroalkyl sulfonic acids.
The unique properties e.g., surface tension lowering in aqueous systems, high chemical and thermal stability of these acids and their derivatives when used at low concentrations resulted in their widespread use in industrial processes and consumer uses.
Changes induced by oxygen protonation in the ether link of dimethyl, diethyl and isopropyl methyl ethers and their perfluorinated analogues are studied by comparing the geometrical structure.
The local proton affinities of phenol and its halogenated derivatives, X-C6H4-OH (X) H, F, Cl, Br, and I) in the C2 (ortho), C3 (meta), and C4 (para) ring carbon positions are determined using DFT and MO methods.
Similar to the process in the parent phenol, the C4. The polymer structure was tailored by introducing a functional C(CF 3) 2 group into the polymer backbone, thereby improving the solubility behavior such that an optimized synthesis affording a pure and solvent free product could be performed.
Optimized gel-type blend polymer electrolyte membranes were produced by variation of the PVdF-HFP to. All measurements were done at 25°C. According to the chemical structures in Fig.
1, the 14 compounds can be divided into four groups: compounds (), compounds (), compounds (), and compounds (). The M concentration data are given because this is close to the optimized. M in ether) to g ( mol) of HMDS in 25 mL of THF at 0 "C, was added g ( mol) of HMPA followed by dropwise addition at "C of g ( mol) of 4 in 10 mL of THF.
After a half an hour, mol of the alkyl halide in 5 mL of THF was added. Similarly, the optimized structure of perfluorotripentylamine, 4, exhibits average CNC bond angles of ° and a nitrogen Å above the plane formed by its neighboring carbons (structure not shown).
It appears likely that the deviation from planarity is in both cases the consequence of steric repulsion between the pentafluoroethyl groups. Most of the fluorinated ethers exhibit relatively high pK a values in DMSO (–), suggesting that the reaction with superoxide as a base 59–62 is unlikely.
The only exception is a hydrogen atom bonded to a tertiary carbon carrying two fluoroalkyl substituents, such as in CH 3 −O−CH(CF 3) 2, which has a rather low pK a value (). Major industrial polymers - Major industrial polymers - Fluorinated polymers: PTFE was discovered serendipitously in by a DuPont chemist, Roy Plunkett, who found that a tank of gaseous tetrafluoroethylene (CF2=CF2) had polymerized to a white powder.
During World War II it was applied as a corrosion-resistant coating to protect metal equipment used in the production of radioactive material. Anion Exchange Membranes: Current Status and Moving Forward Michael A.
Hickner,1 Andrew M. Herring,2 E. Bryan Coughlin3 1Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 2Department of Chemical and Biological Engineering, Colorado School of Mines, Golden, Colorado 3Department of Polymer Science.
Critical physical properties of fluorinated (co)polymers and perfluoropolymers as well as their thermal, mechanical, and physical properties have been supplied in a book chapter. Thus, copolymerizing HFP or perfluoroalkyl vinyl ethers (PAVEs) with TFE led to FEP and PFA, respectively, that exhibit lower melting points (coming from a poorer.
Grimsrud, E.P.; Kebarle, P., Gas Phase Ion Equilibria Studies of the Solvation of the Hydrogen Ion by Methanol, Dimethyl Ether and Water. Effect of Hydrogen Liebman, J.F.; Levin, R.D., Evaluated gas phase basicities and proton affinities of molecules heats of formation of protonated molecules, J Structures and Sequential.
The localization of the proton in a very short hydrogen bridge in proton sponges seems to be a very interesting scientific challenge. A solution to such a challenge has been suggested in a number of structural as well as spectroscopic studies [38,39,40,41,42,43,44,45].Theoretical studies of proton dynamics in a hydrogen bridge are of particular interest [55,56,57,58,59,60,61] because they.
D rug discovery is a difficult and time-consuming process that involves the identification of potent therapeutic agents with good bioavailability, metabolic stability, and low toxicity. An important first step in this process is the identification of molecules that bind with high affinity and selectivity to the biological target.
High-affinity ligands might be discovered by screening natural. Density Functional Theory Studies” Journal of Molecular Structure – THEOCHEM, – 8. Victoria B. Orgel,† David W. Ball, and Michael J.
Zehe. “Optimized Structures and Proton Affinities of Fluorinated Dimethyl Ethers: An Ab Initio Study” NASA Technical Memo #, September14. Optical Properties of Fluorinated Polyimides (FPI) The FPIs of the First Generation InRogers et al. at DuPont  first synthe-sized a fluorinated polyimide from an acid dianhy-dride (6FDA) having two benzene rings connected by a hexafluoro-isopropilidene group (−C(CF 3) 2−: what we call ‘6F linkage’), and diamine (4,4.
An atom of Fluorine in the gas phase, for example, gives off energy when it gains an electron to form an ion of Fluorine.
F + e – → F – – ∆H = Affinity = kJ/mol. To use electron affinities properly, it is essential to keep track of sign.
Density functional theory (DFT) was used for studying the adsorption of dimethyl ether (DME) onto four nanoclusters: X 1 2 Y 1 2 (X = Al, B and Y = N, P).The interaction energy along with the adsorption energy was investigated, and it was found that DME molecule has higher binding energies upon adsorption on Al-containing clusters, but on the other hand, it results in higher alteration in the.
Density Functional Theory Studies” Journal of Molecular Structure – THEOCHEM, – 8. Victoria B. Orgel, † David W. Ball, and Michael J. Zehe.
“Optimized Structures and Proton Affinities of Fluorinated Dimethyl Ethers: An Ab Initio Study” NASA Technical Memo #, September14 .Based on the optimized properties, membrane electrode assembly using XAc-PPO70_25 revealed excellent cell performance (maximum power density: mW/cm2 at V) than those of commercial FAA Fumatech anion exchange membrane (maximum power density: mW/cm2 at V) under the operating condition of 60 °C and % RH as well.Turning our attention to the fluorinated analogs, calculations were carried out for the 5- 6- 9- and fluorinated derivatives of 7-MBA.
Fluorination at C was analyzed in order to reveal any influence that may be exerted by the fluorine atom when located in a bay region, and the 7-FBA was considered for comparison with 7-MBA.