zing cellulose acetate particles from ramie fiber was developed. The optimum conditions for preparing cellulose acetate (CA) by reaction of ramie fiber with acetic anhydride under an acidic condition were determined. Reaction was carried out in a ratio of ramie fiber to acetic anhydride of 1:6 (w/w) at 80 _C for 0.5–1 h. When CA was added to a mixture of water and acetone, CA particles with a well-distributed diameter ranging from 5 to 15 lm were obtained. The difference of the CA particle surface was resulting from different washing methods of CA particles with water or aqueous sodium bicarbonate. The highest degree of substitution (DS) of 2.50 for CA by titration method was achieved. A new adsorbent was prepared from CA, which is an excellent sorption regent for organic waste in water. The scanning electron microscopy (SEM) and particle size distribution results showed that the average size of CA particles is about 5–15 lm in diameter. The thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to determine the stability of ramie fiber and CA particle. 2006 Elsevier B.V. All rights reserved.

A series of fluorinated analogues of AOT, the sodium salt of bis(3,3,4,4,5,5,6,5,7,7,8,8,8-tridecafluorooctyl)-2-sulfosuccinate (CF3(CF2)5CH2CH2OOCCH2CH(SO3Na)COOCH2CH2(CF2)5CF3, di-HCF7),the sodium salt of bis(2,2,3,3,4,4,5,5-octafluoro-1-pentyl)-2-sulfosuccinate (H(CF2)4CH2OOCCH2CH-(SO3Na)COOCH2(CF2)4H, di-HCF4), and the sodium salt of bis(2,2,3,4,4,4-hexafluorobutyl)-2-sulfosuccinate(CF3CHFCF2CH2OOCCH2CH(SO3Na)COOCH2CF2CHFCF3, di-HCF3), were synthesized and characterized by 1HNMR. The pressure-temperature phase diagrams for W/CO2 microemulsions stabilized by the three surfactants were determined. At a fixed temperature, cloud point pressures increased with increasing water-to-surfactant ratio. The water solubilization capacity increased in the order di-HCF4 > di-HCF3 > di-HCF7.

A series of novel fluorinated analogues of sodium bis(2-ethylhexyl) sulfosuccinate (AOT) surfactants, the sodium salt of bis(3,3,4,4,5,5,6,6,6-nonafluoro-1-hexanol) sulfosuccinate (CF3(CF2)3CH2CH2OOCCH2CH(SO3Na)COOCH2CH2(CF2)3CF3, di-HCF5), the sodium salt of bis(2,2,3,4,4,4-hexafluoro-1-butanol) sulfosuccinate (CF3CFHCF2CH2OOCCH2CH(SO3Na) COOCH2CF2CFHCF3, di-HCF3), the sodium salt of bis(2,2,3,3- tetrafluoro-1-propanol) sulfosuccinate (HCF2CF2CH2OOCCH2CH(SO3Na)COOCH2CF2CF2H, di-HCF2), and the sodium salt of bis(2,2,3,3,3-pentafluoro-1-propanol) sulfosuccinate (CF3CF2CH2OOCCH2CH(SO3Na)COOCH2CF2CF3, di-CF2), were synthesized and characterized by 1H NMR, 13C NMR, 19F NMR and FT-IR spectroscopy, melting point, and elemental analysis. The pressure–temperature phase behavior for water-in-CO2 microemulsions stabilized by the four surfactants was tested and the P–T diagrams were determined. In the phase behavior experiments, pressures up to 35 MPa, temperatures up to 65 uC, and water-to-surfactant molar ratios (Wo) from 10 to 30 were tested. The cloud-point pressure in microemulsions stabilized by the four fluorinated surfactants increased with increasing temperature, and at a fixed temperature, the cloud-point pressure increased with increasing Wo. However, the cloud-point pressure was only slightly affected by an increase in the concentration of surfactant at a settled Wo. The phase behavior for water-in-CO2 microemulsions at different Cd(NO3)2 concentrations in the aqueous phase with the surfactant di-HCF5 was also determined, which is useful for the formation of CdS nanoparticles in our future studies.

A modification procedure for ramie fiber using 3-chloro-2-hydroxypropyltrimethyl ammonium chloride (CHPTAC) as a cationic agent and NaOH as a catalyst was developed in this paper. The morphological and structutal transformations of the fiber induced by modification were determined by XRD(XRD),differential scanning calorimetry (DSC), and thermogravimetry analysis(TGA).XRD results show that the crystal structure of the modified fiber was still preserved although its crystallinity was decreased, which was confirmed from the TGA results. The mechanisms for the modification and dyeing of ramie fiber were analyzed,and the optimum modification conditions were determind to ba the CHPTAC concentration of 30gL-1, the NaOH concentration of 15gL-1,the reaction temperature of 50℃,and the reaction time of 60 min.The raw and the modified fibers were dyed with C.I. reactive red 2. The K/S values for the cationic modified fiber increased to be three times as high as the unmodified fiber. The dye uptakes increased greatly with an increase in the nitrogen contents up to 0.4% on the modified fibers.

The catalytic synthesis of methyl acrylate by hydroesteri cation of acetylene with methyl formate was studied under various conditions. Mixtures of nickel acetate tetrahydrate, copper sulfate pentahydrate and sodium iodide dihydrate were used as catalysts, and N,N-dimethylformamide as solvent. The experimental results concerning the effects of the reaction condition on selectivity to methyl acrylate, methanol and methyl propionate suggested the synthesis of methyl acrylate through the carbonylation reaction of acetylene. When the reaction was carried out under the total initial pressure of 6.0 Mpa and the CO initial partial pressure of 3.0 MPa at the temperature of 1808C with the catalyst composition of 0.040 M Ni(OAc)2_4H2O and 0.054 M NaI_2H2O, 86% selectivity to methyl acrylate and 64% conversion of methyl formate were achieved. # 1998 Elsevier Science B.V. All rights reserved.