Solvent free telomerization of butadiene with water into octadienols in the presence of nonionic surfactant: efficient micellar catalysis

Telomerization of butadiene with water into 2,7-octadien-1-ol using a palladiumhydrosoluble phosphine system was investigated. The reaction was carried out without solvent in the presence of carbon dioxide and a nonionic surfactant. Promoted effect of neutral surfactant appeared above the critical micelle concentration and the conversion and the selectivity depended on the structure of nonionic surfactant hydrophilic part. The role of the nonionic surfactant is discussed.     

Foaming properties of surfactin,a lipopeptide biosurfactant fromBacillus subtilis

Foaming properties of surfactin were investigated and compared to those of sodium dodecyl sulfate (SDS) and bovine serum albumin (BSA). Foams were formed by a bubbling technique. Evolution of the foam volume and the liquid in the foam was monitored with optical and conductimetric methods to characterize foam formation and stability. Excellent foaming properties of surfactin were shown by its higher ability to form and stabilize the foam at a concentration as low as 0.05 mg/mL, in comparison with SDS and BSA. Surfactin produced a foam with intermediate maximum density and stabilized the liquid in foam, as well as BSA.     

Recursive decomposition and bounds of the lattice of Moore co-families

A collection of sets on a ground set U _n (U _n ?=?{1,2,...,n}) closed under intersection and containing U _n is known as a Moore family. The set of Moore families for a fixed n is in bijection with the set of Moore co-families (union-closed families containing the empty set) denoted $\mathbb{M}_n$ . In this paper, we propose a recursive definition of the set of Moore co-families on U _n . Then we apply this decomposition result to compute a lower bound on $|\mathbb M_n|$ as a function of $|\mathbb M_{n-1}|$ , the Dedekind numbers and the binomial coefficients. These results follow the work carried out in [1] to enumerate the number of Moore families on U ₇.     

Oxygen mediated and wavelength tunable cationic photopolymerization reactions under air and low intensity: A new concept

A new concept which allows efficient cationic photopolymerization reactions under air, at any excitation wavelength in the UV–visible range and under low light intensities (conventional Xe lamp and/or laser diodes) is presented. It is based on the use of a versatile free radical promoted cationic process for the photoinitiation step which only requires a radical source, a silane and an usual iodonium salt and takes advantage of the presence of oxygen. The tunable character of the absorption is connected with the choice of the radical source. The oxygen enhancement is due to the particular role played by the silane. In every case, the silylium cation is the most efficient structure for the cationic ring opening reaction. Examples of the performance achieved (e.g. a conversion close to 100%) with such systems over the 390–580 nm range using various irradiation devices is shown and discussed.     

New rheological method to measure diffusion coefficient of volatile liquids: Application to butylmethacrylate in molten polyethylene matrix

A rheological method to assess the diffusion behavior of liquids in molten polymers above their boiling point is presented in this article. The evaporation of the liquid and the evolution of the blends complex modulus are followed by rheological measurement. Identification of the Fick's diffusion coefficient and the rate of evaporation of butylmethacrylate in low density polyethylene is done. The values of the diffusion coefficient are in agreement with those obtained by classical methods. The method developed here appears as complementary to the existent ones. It allows the measurement of diffusion coefficient of liquid/polymer system at high temperatures even for volatiles liquids. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010