The capillary extrusion property of ethylene–tetrafluoroethylene copolymer (ETFE) is evaluated. It is found that ETFE shows several types of flow instabilities. The shark-skin failure is observed over the first critical shear stress 7.9 × 104 Pa. Then, the slip-stick instability is detected at...

In this work, poly (tetrafluoroethylene-co-hexafluoropropylene) (FEP) hollow fiber membranes were fabricated by melt-spinning method with solvent-free condition, while no coagulation bath was involved. The robust and solvent-free method for preparation of FEP hollow fiber greatly reduced environ...

The mechanism of environmental intercrystallite crazing (EIC) of semicrystalline poly(tetrafluoroethylene) (PTFE) films was studied. Stress-induced cavitation and fibrillation upon the EIC process provides the development of a marked porosity in PTFE (up to ∼40%) and pores with nanoscale dimens...

Two novel perfluorinated materials, copolymers of tetrafluoroethyelene (TFE) and hexafluoropropylene (HFP), were prepared and studied. In both copolymers the prevailing comonomer was HFP. The copolymers are completely amorphous and similar by their properties to poly(hexafluoropropylene) studied...

In this article, we revealed synthetic utilization of thermally stable as well as easy-handling triethyl (1,1,2,2-tetrafluorobut-3-en-1-yl)silane as the tetrafluoroethylenating agent through Cu(I)-mediated cross-coupling reaction with various iodoarenes, which would offer promising building bloc...

The use of tetrafluoroethylene (TFE) in academic institutions beyond a few millimoles has often been inhibited by the compound's inherent danger and general lack of commercial availability. On the other hand, TFE is prepared industrially on a rather large scale by a number of major fluoroch...

Tetrafluoroethylene (TFE) is a fluorine-based monomer, which belongs to the family of fluorocarbons. It has the chemical formula C2F4, which is like ethylene or ethene (C2H4 or H2CCH2). TFE is the simplest per-fluorinated alkene. In the industry, TFE is used primarily in the preparation of polym...

The changes of the surface morphology of poly(tetrafluoroethylene) due to proton irradiation was investigated. 1 MeV proton beam was used for the irradiations with relatively low current densities, in the range of 10–100,000 pA/mm2. The applied ion fluences ranged from 0.1 to 2500 nC/mm2 (6.24 ...

The rotational isomerism of the title compound, CH2C(CH3)OCH3, has been studied by i.r. spectroscopy. The spectra reveal the presence of two conformational isomers in the fluid phases. The energy difference between them is estimated to be 0.85 kcal/mole in the liquid state. From the shapes of ...

d-Lyxose (1) undergoes acetonation under kinetic conditions with 2-methoxypropene to give 2,3-O-isopropylidene-α-d-lyxofuranose (2) in high yield, further characterized as its 1,5-diacetate 3, thus affording a preparative route to 2. Forcing conditions are required to bring d-xylose (5) into re...

The acetonation of lactose with 2-methoxypropene afforded 4,6-O-isopropylidene lactose (2) and a diacetal which, after acetylation, gave an α,β-anomeric mixture of 1, 2,6,3'-tetra-O-acetyl-3,2':4',6'-di-O-isopropylidene lactose (4). Acetonation of benzyl b-lactoside afforde...

In the superbase catalytic systems ButOK/NMP, AmtOCs/NMP and KOH/DMSO, methanol readily adds to propyne and allene at 100–120 °C and atmospheric pressure to afford 2-methoxypropene in 80–97% yield with 75–94% methanol conversion.

The chemical thermodynamics of sorption enhanced steam reforming (SESR) of hydroxyacetone for hydrogen production were investigated and contrasted with hydroxyacetone steam reforming (SR) by means of Gibbs free energy minimization principle and response reactions (RERs) method. Hydrogen is mainl...

Lactic acid is an important chemical with a wide range of application in food, pharmaceutical and chemical industries. Its worldwide demand has increased due to the ever-growing market of poly(lactic acid) – PLA. This present contribution aims at studying the catalytic transformation of hydroxy...

Catalytic reforming of three typical bio-oil model compounds, phenol, acetic acid and hydroxyacetone, has been carried out over a Ni/nano-Al2O3 catalyst. Al2O3, in the form of nano-rods of length approximately 40 nm, was selected as the catalyst support. The catalyst showed superior performance ...

In situ Attenuated Total Reflection Infrared (ATR-IR) spectroscopy was used to study Aqueous Phase Reforming of hydroxyacetone on Pt/AlO(OH) and Pt/ZrO2 catalysts at 230 °C/ 30 bar. Formation of strongly adsorbed aldol condensation products was observed on the surface of Pt/ZrO2 and ZrO2 in con...

In this work conventional organic solvents (ethyl acetate, n-propyl acetate, n-butyl acetate, chloroform) as well as ionic liquids, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][Tf2N]) and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIM][Tf2N]), were ...

The gas phase dehydration of glycerol to hydroxyacetone was investigated over La2CuO4 catalyst under inert conditions. The reaction was performed in the temperature range of 260–400 °C. At low temperature (260 and 280 °C) high yields of hydroxyacetone can be achieved: 76% while at higher temp...

During fast pyrolysis of biomass, hydroxyacetone (HA, also known as 1-hydroxy-2-propanone) is a vital linear ketone product from fragmentation (ring scission) of cellulose. In this study, density functional theory (DFT) calculations are employed to reveal the HA formation mechanisms and pathways...

Methacrolein (MACR) is an abundant multifunctional carbonyl compound with high reactivity in the atmosphere. In this study, we investigated the hydroxyl radical initiated oxidation of MACR at various NO/MACR ratios (0 to 4.04) and relative humidities (