含CF3CF2CF2C(CF3)2基团支链型氟表面活性剂的合成及性能研究

全氟辛酸/全氟辛基磺酸(PFOA/PFOS)类氟表面活性剂因不易被生物降解且对环境有毒害作用, 被列为持久性有机污染物. 采用引入氟碳支链的策略作为PFOA/PFOS替代物的研发取向, 以六氟丙烯二聚体为原料合成了新型阳离子型、两性型、双子型和非离子型氟表面活性剂, 并对它们的表面活性和急性毒性性能进行了测试. 结果表明, 所合成的支链型表面活性剂表面活性高且毒性低. 因此, 基于六氟丙烯二聚体(HFPD)合成PFOS/PFOA替代物是一种简单、经济且环保的方法.     

Selected Ion Flow Tube Study of the Gas-Phase Reactions of CF(+), CF(2)(+), CF(3)(+), and C(2)F(4)(+) with C(2)H(4), C(2)H(3)F, CH(2)CF(2), and C(2)HF(3)

We study how the degree of fluorine substitution for hydrogen atoms in ethene affects its reactivity in the gas phase. The reactions of a series of small fluorocarbon cations (CF(+), CF(2)(+), CF(3)(+), and C(2)F(4)(+)) with ethene (C(2)H(4)), monofluoroethene (C(2)H(3)F), 1,1-difluoroethene (CH(2)CF(2)), and trifluoroethene (C(2)HF(3)) have been studied in a selected ion flow tube. Rate coefficients and product cations with their branching ratios were determined at 298 K. Because the recombination energy of CF(2)(+) exceeds the ionization energy of all four substituted ethenes, the reactions of this ion produce predominantly the products of nondissociative charge transfer. With their lower recombination energies, charge transfer in the reactions of CF(+), CF(3)(+), and C(2)F(4)(+) is always endothermic, so products can only be produced by reactions in which bonds form and break within a complex. The trends observed in the results of the reactions of CF(+) and CF(3)(+) may partially be explained by the changing value of the dipole moment of the three fluoroethenes, where the cation preferentially attacks the more nucleophilic part of the molecule. Reactions of CF(3)(+) and C(2)F(4)(+) are significantly slower than those of CF(+) and CF(2)(+), with adducts being formed with the former cations. The reactions of C(2)F(4)(+) with the four neutral titled molecules are complex, giving a range of products. All can be characterized by a common first step in the mechanism in which a four-carbon chain intermediate is formed. Thereafter, arrow-pushing mechanisms as used by organic chemists can explain a number of the different products. Using the stationary electron convention, an upper limit for Δ(f)H°(298)(C(3)F(2)H(3)(+), with structure CF(2)═CH-CH(2)(+)) of 628 kJ mol(-1) and a lower limit for Δ(f)H°(298)(C(2)F(2)H(+), with structure CF(2)═CH(+)) of 845 kJ mol(-1) are determined.     

Hydrogen abstraction from CF3CF2CFH2 and CF3CFHCF2H by OH radicals and Cl atoms: theoretical enthalpies and rate constants

The hydrogen abstraction reactions of CF₃CF₂CFH₂ and CF₃CFHCF₂H with OH radicals and Cl atoms have been studied theoretically by a dual-level direct dynamics method. Two stable conformers of CF₃CF₂CFH₂ with C _s and C ₁ symmetries and all possible abstraction channels for each reaction are all taken into consideration. Optimized geometries and frequencies of all the stationary points and extra points along minimum-energy path (MEP) have been computed at the BB1K/6-31+G(d, p) level of theory. To refine the energy profile of each reaction channel, single point energy calculations have been performed by the BMC-CCSD method. The rate constants are evaluated by canonical variational transition state theory (CVT) with the small-curvature tunneling correction method (SCT) over a wide temperature range of 200–1,000 K. The detailed branching ratios of four reactions are discussed. The good agreement found between our theoretical rate constants and the available experimental data suggests that the present approach could provide a reliable prediction for the CF₃CFHCF₂H + Cl reaction about which there is little experimental information. The kinetic calculations show that the SCT effect plays an important role in all channels. In addition, in order to further reveal the thermodynamic properties, the enthalpies of formation of the reactants (CF₃CF₂CFH₂ and CF₃CFHCF₂H) and the product radicals (CF₃CF₂CFH, CF₃CFCF₂H, and CF₃CFHCF₂) are evaluated by applying isodesmic reactions at both BMC-CCSD//BB1K/6-31+G(d, p) and MC-QCISD//BB1K/6-31+G(d, p) levels of theory.     

(CF3)2PAsH2 und (CF3)2AsAsH2

(CF₃)₂PAsH₂ and (CF₃)₂AsAsH₂ (CF₃)₂PAsH₂ is obtained in yields between 30 and 60% according to eq. (1) (CF₃)₂AsAsH₂ is formed by the analogous reaction with (CF₃)₂AsI, but is not sufficiently stable to be isolated. Both compounds are decomposed according to eq. (2) (CF₃)₂PAsH₂ can be studied in solution below ?40°C; it is characterized by molar mass determination and by its n.m.r. spectra (¹H, ¹⁹F, ³¹P). Reactions with polar [HBr, (CH₃)₂AsH, (CH₃)₂PN(CH₃)₂] and nonpolar [Br₂, As₂(CH₃)₄] reagents proceed by cleavage of the P? As bond.     

The fluorine atom initiated oxidation of CF3CFH2 (HFC-134a) studied by FTIR spectroscopy

Experiments have been carried out on the oxidation of CF₃CFH₂ (HFC-134a). Reaction was initiated by continuous photolysis of F₂ in the near-ultraviolet. The F atoms produced abstracted a hydrogen atom from CF₃CFH₂ initiating oxidation in gas mixtures containing O₂ and made up to a total pressure of 700 torr with N₂. Product yields were measured using Fourier-transform infrared (FTIR) spectroscopy. Experiments were performed with several different partial pressures of O₂ present, and at three temperatures; 298, 323, and 357 K. The major products were HC(O)F, CF₃C(O)F, and CF₃O₃CF₃, consistent with H atom abstraction by O₂ and CC bond scission being the dominant loss processes for CF₃CFHO radicals: CF₃CFHO+0₂ → CF₃C(O)F+HO₂ (4a) CF₃CFHO+M → CF₃+HC(O)F+M (4b) The following expression was derived for the ratio of rate constants for these reactions: k_4a/k_4b=(3.8±1.6)×10⁻²⁴ exp[(2400±500)/T]cm³ molecule⁻¹ (viii) The main fate of the CF₃ radicals was formation of CF₃O₃CF₃ and small amounts of CF₃OH were detected. The results of the present experiments in which F atoms were used to initiate reaction are in good agreement with those of previous studies in which Cl atoms were employed to initiate the oxidation of HFC-134a. © 1998 John Wiley & Sons, Inc. Int J Chem Kinet 30: 541–554, 1998     

The thermodynamic effect of fluorine as a substituent: Vinylic CF2 and CFH and allylic CF2C

I₂-catalyzed isomerizations of 3-fluoropropene and 3,3 - difluoropropene, and a Cope rearrangement of 1,1 - difluoro - 1,5 - hexadiene provide thermodynamic data which allow the determination of a number of important group values for contributions to ΔH^o_f which when combined with those determined in the preceding paper allow the calculations of ΔH^o_f's of most simple F-substituted hydrocarbons: [C_d(F)(H)] = ? 38.4, [C_d(F)₂] = ? 88.0, [C(F)₂(C)(C_d)] = ? 103.9, [C(F)₂(C)₂] = ? 104.9 kcal/mole. A kinetic study of the conversion of 1,1 - difluoro- to 3,3 - difluoro - 1,5 - hexadiene provided activation parameters for the process: Log A = 10.8, E_a = 33.0 kcal/mole and ΔS^≠ = ? 12.2 e.u. Incremental geminal stabilizations of F and other substituents are discussed and contrasted.     

Dissociation and IVR pathways for the CF3H(H2O)3 cluster

Classical trajectory simulations are used to study the intramolecular dynamics of isolated CF₃H and the CF₃H(H₂O)₃ cluster, by either exciting the CH stretch local mode to then=6 level or by adding an equivalent amount of energy to an OH stretch normal mode. Energy transfer from the CH local mode is statistically the same for CF₃H(H₂O)₃ as for isolated CF₃H, and agrees with previous experimental studies. Clusters excited with 6 quanta in the CH local mode are remarkably stable. Though the CF₃H-(H₂O)₃ intermolecular potential is only 1.5 kcal/mol, only 1 of 26 clusters excited with 6 quanta in the CH local mode dissociate within 10 ps. The absorption linewidth for the CH local mode in CF₃H(H₂O)₃ is related to IVR within CF₃H and not to the unimolecular lifetime of the cluster. When an OH stretch normal mode of the cluster is excited, energy transfer to CF₃H is negligible and nearly one half of the clusters dissociate within 10 ps.     

Perfluoralkyltellur-Verbindungen: Oxidation von (CF3)2Te Darstellungen und Eigenschaften von (CF3)2TeCl2, (CF3)2TeBr2, (CF3)2Te(ONO2)2 und (CF3)2TeO [1]

Perfluorosalkyl Tellurium Compounds: Oxidation of (CF₃)₂Te; Preparations and Properties of (CF₃)₂TeCl₂, (CF₃)₂TeBr₂, (CF₃)₂Te(ONO₂)₂, and (CF₃)₂TeO From the oxidation of (CF₃)₂Te with Cl₂, Br₂, O₂, and ClONO₂ the new trifluoromethyl tellurium compounds (CF₃)₂TeCl₂, (CF₃)₂TeBr₂, (CF₃)₂TeO, and (CF₃)₂Te(ONO₂)₂ are prepared. The ¹⁹F, ¹³C and ¹²⁵Te n.m.r. spectra, the vibrational and mass spectra as well as the chemical properties of these compounds are described. By variation of the reaction conditions CF₃TeCl₃ and CF₃TeBr₃ are also formed. It has not been possible to isolate (CF₃)₂TeI₂, but there is some evidence that it is formed as an intermediate. (CF₃)₂Te reacts with ozone to a very unstable compound, which decomposes at low temperature.     

Die Gasphasenstrukturen von CF3NBr2 und (CF3)2NBr

The Gas Phase Structures of CF₃NBr₂ and (CF₃)₂NBr The gas phase structures of the trifluoromethyl bromoamines CF₃NBr₂ and (CF₃)₂NBr were determined by electron diffraction. CF₃NBr₂: N? Br = 188.0(3), N? C = 148.1(13) pm, BrNBr = 111.1(6)° and BrNC = 107.3(8)°; (CF₃)₂NBr: N? Br = 186.9(4), N? C = 144.9(7) pm, BrNC = 114.9(9)° and CNC = 118.6(24)°. The results for these bromoamines are compared to those for the analogous fluoro and chloroamines.     

Kinetics of the reactions of halogenated methyl radicals (CF3, CF2Cl,CFCl2, and CCl3) with molecular chlorine

The kinetics of four gas-phase reactions involving halogenated methyl radicals (R ? CF₃, CF₂Cl, CFCI₂, and CCI₃) with molecular chlorine have been studied using a tubular reactor coupled to a photoionization mass spectrometer. The radicals were homogeneously generated by the pulsed photolysis of precursor molecules at 193 nm. The subsequent decays of the radical concentration were monitored in real-time experiments as a function of Cl₂ concentration to obtain the rate constants of these R + Cl₂ reactions. Where possible, the rate constants were measured as a function of temperature to determine Arrhenius parameters. Apparent discrepancies between these measured rate constants for CF₃ and CCl₃ with Cl₂ and ones obtained in prior indirect studies are explained. The higher activation energies for these R + Cl₂ reactions compared to that of the CH₃ + Cl₂ reaction are attributed in part to the different polarities of the transition states formed.     

Darstellung und charakterisierung von (CF3)2PPH2 und (CF3)2AsPH2

(CF₃)₂EPH₂ (E = P,As) may be prepared in high yield by the cleavage of M-P bonds in compounds of the type R₃MPH₂ (M = Si, Ge, Sn) with (CF₃)₂EX (X = Cl, Br, I). The direction of bond fission depends on X and on the reaction temperature. These new compounds may also be obtained, but in lower yield, by the reaction of LiAl(PH₂)₄ with (CF₃)₂EX. Application of the principle of this reaction to other R′₂EX compounds [(CH₃)₂PCl, (CH₃)₂AsI, F₂PX (X = Br, I)] has been investigated. The IR and NMR spectra of the new compounds are reported.     

Design and synthesis of the novel branched fluorinated surfactant intermediates with CF3CF2CF2C(CF3)2 group

Here we reported a novel and efficient method for the synthesis of the critical intermediates of branched fluorinated surfactants with CF₃CF₂CF₂C (CF₃)₂- group using HFPD as starting material. The reaction conditions were mild and easy to handle, which was promisingly applied to the industrial production.     

Li+ cation coordination in [Li2(CF3SO3)2(diglyme)] and [Li3(C2F3O2)3(diglyme)]

The title compounds, poly­[[[bis(2‐methoxy­ethyl) ether]­lithium(I)]‐di‐μ₃‐tri­fluoro­methanesulfonato‐lithium(I)], [Li₂(CF₃SO₃)₂(C₆H₁₄O₃)]_n, and poly­[[[bis(2‐methoxy­ethyl) ether]­lithium(I)]‐di‐μ₃‐tri­fluoro­acetato‐dilithium(I)‐μ₃‐tri­fluoro­acetato], [Li₃(C₂F₃O₂)₃(C₆H₁₄O₃)]_n, consist of one‐dimensional polymer chains. Both structures contain five‐coordinate Li⁺ cations coordinated by a tridentate diglyme [bis(2‐methoxy­ethyl) ether] mol­ecule and two O atoms, each from separate anions. In both structures, the [Li(diglyme)X₂]^? (X is CF₃SO₃ or CF₃CO₂) fragments are further connected by other Li⁺ cations and anions, creating one‐dimensional chains. These connecting Li⁺ cations are coordinated by four separate anions in both compounds. The CF₃SO₃^? and CF₃CO₂^? anions, however, adopt different forms of cation coordination, resulting in differences in the connectivity of the structures and solvate stoichiometries.     

Rate constants for the reactions of OH radicals with CH3OCF2CF3, CH3OCF2CF2CF3, and CH3OCF(CF3)2

The rate constants for the reactions of OH radicals with CH₃OCF₂CF₃, CH₃OCF₂CF₂CF₃, and CH₃OCF(CF₃)₂ have been measured over the temperature range 250–430 K. Kinetic measurements have been carried out using the flash photolysis, laser photolysis, and discharge flow methods combined respectively with the laser induced fluorescence technique. The influence of impurities in the samples was investigated by using gas‐chromatography. The following Arrhenius expressions were determined: k(CH₃OCF₂CF₃) = (1.90) × 10⁻¹² exp[−(1510 ± 120)/T], k(CH₃OCF₂CF₂CF₃) = (2.06) × 10⁻¹² exp[−(1540 ± 80)/T], and k(CH₃OCF(CF₃)₂) = (1.94) × 10⁻¹² exp[−(1450 ± 70)/T] cm³ molecule⁻¹ s⁻¹. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 846–853, 1999     

Characterization by NMR of reactants and products of hydrofluoroether isomers,CF3(CF2)3OCH3 and (CF3)2C(F)CF2OCH3, reacting with isopropyl alcohol

The 3M Company product Novec? 71IPA DL, a mixture of methoxyperfluorobutane, methoxyperfluoroisobutane and 4.5 wt.% isopropyl alcohol, has been found to be very stable at ambient temperature, producing fluoride at the rate of ~1 ppm/year. Our earlier kinetic and theoretical studies have identified the reaction mechanism. This paper identifies the ¹H and ¹⁹F NMR chemical shifts, multiplicities, and coupling constants of reactants and the major products that result from aging the mixture in sealed Pyrex NMR tubes for periods up to 1.8 years at temperatures from 26 °C to 102 °C. Chemical shifts and coupling constants of fluorine and hydrogen atoms on the hydrofluoroethers and isopropyl alcohol are traced through the reactions to their values in the products – esters, isopropylmethyl ether, and HF. These spectral positions, multiplicities, and coupling constants are presented in table format and as figures to clarify the transformations observed as the samples age. Copyright © 2013 John Wiley & Sons, Ltd.     

Preparation and Structure of [Me3N(CF3)2BCCB(CF3)2NMe3]

Bis‐trimethylamine‐ethynyl‐di‐bis(trifluoromethyl)borane [Me₃N(CF₃)₂BCCB(CF₃)₂NMe₃] ( 1 ) has been prepared from trimethylamine‐ethynyl‐bis(trifluoromethyl)borane, [HCCB(CF₃)₂NMe₃], and dimethylamino‐bis(trifluoromethyl)borane, (CF₃)₂BNMe₂. The structure of 1 has been determined by x‐ray crystallography. In the solid state the molecule possesses crystallographic C_i symmetry. The acetylenic attachment to the boron atom is characterized by a short B–C bond length of 1.565(4) Å and an essentially linear B–C–C′ bond angle of 178.1(4)°.     

Coordination networks with flexible ligands based on silver(I) salts: complexes of 1,3-bis(phenylthio)propane with silver(I) salts of PF6-, CF3COO-, CF3CF2COO-, CF3CF2)CF2COO-, p-TsO-, and CF3SO3-

The synthesis and characterization of nine coordination networks based on 1,3-bis(phenylthio)propane, L(3), and silver(I) salts of PF(6)(-) (1), CF(3)COO(-) (2), CF(3)CF(2)COO(-) (3), CF(3)CF(2)CF(2)COO(-) (4), p-TsO(-) (5, 6), and CF(3)SO(3)(-) (7-9) are reported. Only 1 and other "isostructural" complexes with weakly coordinating anions such as ClO(4)(-) and SbF(6)(-) are of the host-guest type. In all the other complexes, the anions and the acetone molecules, when present, are coordinated to the metal. Most of the complexes studied here form a 2D-coordination network. Only 4 and 5 adopt a polymer-like chain structure. The packing of the chains of 4 is pseudohexagonal compact, while that of 5 is of the centered type. In complex 1, the silver atom is tetrahedrally coordinated to the sulfur atoms of four different ligands. The PF(6)(-) anions and acetone molecules, sandwiched between silver-ligand cationic sheets, are held through van der Waals interactions. In each of the three perfluorocarboxylates (2-4), two silver atoms are joined by the anions in a diatomic bridging mode. The Ag...Ag distances are sufficiently short to indicate weak metal...metal interactions. The dimeric units in 2 and 3 are interconnected through the ligands, thereby generating a 2D-network of neutral sheets, while, in 4, the dimeric units are bound to four ligands and a 1D-coordination polymer is generated. In the case of the sulfonate anions (p-TsO(-) and CF(3)SO(3)(-)), the crystallization solvent influences the structure adopted. Thus, in 5, 7, and 9 obtained from petroleum ether, or other nonpolar solvents, two silver atoms are bound in a double-bridge fashion, while a monobridge mode is noted for 6 and 8, both recrystallized from diethyl ether. In 8, both bridging types are observed. The thermogravimetric investigation, in the room temperature-450 degrees C interval, of complexes 1, 3, and 7, which incorporate acetone molecules in their crystal structures, reveals a two-step weight loss for 1 (the acetone molecules are lost first followed by the ligands, leaving behind the silver salt), while complexes 3 and 7 decompose in a single step to metallic silver.     

Synthese,Kristallstruktur und magnetisches Verhalten von Gd(CF3CF2COO)3(H2O)3

Synthesis, Crystal Structure and Magnetic Behaviour of Gd(CF₃CF₂COO)₃(H₂O)₃ Single crystals of Gd(CF₃CF₂COO)₃(H₂O)₃ have been obtained by reaction of Gd₂O₃ with an aqueous solution of CF₃CF₂COOH. The compound crystallizes triclinically in the space group (No. 2; Z = 2; a = 928.5(1) pm, b = 1037.1(1) pm, c = 1147.3(2) pm, α = 90.44(2)°, β = 108.56(1)°, γ = 106.49(1)°). In the crystal structure the gadolinium ions are bridged by carboxylate groups to dimers and are coordinated eightfold by oxygen atoms. The magnetic behaviour was investigated in the temperature range of 1.77 to 300 K. The magnetic data indicate weak antiferromagnetic interactions within the dimeric unit (J_ex = ?0.0057 cm^?1).