Fluid phase equilibrium studies on model substances for supercritical fluid extraction with CO2 up to 100 MPa

Abstract

Multicomponent fluid phase equilibrium data are of increasing interest for applications in Supercritical Fluid Extraction (SFE) where compressed supercritical gases are used for the extraction of low-volatile substances (e.g. caffeine from coffee and tea, hops etc.). Sometimes so-called moderator substances have to be added in order to increase solvent power and/or selectivity. Systematic measurements on a four-component system of the type CO₂ + fatty alcohol (e.g. 1-do-decanol) + alkane (e.g. hexadecane) as a function of the amount of moderator added were performed at 393 K and at pressures from 10 to 100 MPa in an analytical high-pressure cell. Separation factors calculated from the p,T,w/,w, “data are presented and discussed.     

A New Approach to Fabricating Cellulosic–Polymer Composites

The versatility of a process designed to fabricate bicontinuous cellulose–polymer composite has been explored. Bulk samples of bamboo, aspen, black cherry and pine were impregnated with a silicone mixture which was then crosslinked in situ. Incorporation of silicone was confirmed by mass uptake, optical microscopy, infrared spectroscopy, elemental analysis, and thermogravimetric analysis (TGA). Mechanical properties of each material were measured before and after silicone incorporation. In most cases, the density of the composites increases significantly, the ultimate strength of the composite materials is improved, and modulus is unaffected. One notable exception is that pine exhibits a significant increase in both modulus and ultimate strength. Char yield was measured by TGA and all composites exhibit a significant increase of char formation compared to the untreated samples.     

超临界二氧化碳介质中有机化学反应研究

综述了本研究小组近年来在超临界二氧化碳介质中过渡金属催化的有机化学反应的研究结果,主要包括烯烃和炔烃的羰基化反应、氧化反应、自由基反应、低聚反应。     

Preparation of Silica/Poly(divinylbenzene) Composite Particles by Dispersion Polymerization in Supercritical Carbon Dioxide

Silica/poly(divinylbenzene) (PDVB) composite particles were synthesized by the dispersion polymerization of divinylbenzene (DVB) with ultrafine silica particles in supercritical carbon dioxide (scCO₂). Silica particles of average diameter 130 nm were pretreated with 3-(trimethoxysilyl) propyl methacrylate in order to be well dispersed in CO₂ and participated in the polymerization. Random copolymeric dispersant, poly(diisopropylaminoethyl methacrylate-co-heptafluorobutyl methacrylate) was used as a stabilizer to provide sufficient stabilization to latexes in scCO₂ and the silica/PDVB composite powder was obtained in high yield from the polymerization. SEM analysis revealed that the composite particles prepared at 5% silica loading ratio and 6% stabilizer concentration with respect to monomer have the average diameter of 1.60 μm with uniform and spherical morphology. The composites were also characterized by FTIR spectroscopy and TGA.