Spent catalyst samples from hydrogenation of palm and palm kernel oils were subjected to soxhlet extraction to remove oil residue, digestion with concentrated sulfuric acid and nickel extraction using chelating ion exchange resin. The results showed that the spent catalysts contained oil residue (42.2-54.0%), nickel (11.32-15.63%), Mg (1.65-2.51%), Ca (3.84-5.68%). Other metals, Fe, K, Na, K, Al, Zn, Cu, Cr and Mn are minor components (<0.1%). The Amberlite IRC-718 resin has extracted more than 90% Ni in the spent catalysts (as nickel nitrate) with purity of higher than 90% with regards to the amount of Mg and Ca in the sample. The Amberlite resin showed the highest sorption capacity for Ni(II) (56.8 mg⁄g) at pH 5.
Surface tension measurements were carried out for aqueous solutions of polyoxyethylene oleyl and stearyl ethers with average number of oxyethylene units of 20 (abbreviated as POEOl and POESt, respectively) in order to examine the effect of introducing a double bond into hydrocarbon chain on the surface activity of the surfactants. The overall features of surface chemical properties of these two surfactant solutions are similar to each other, although the surface tension and the critical micelle concentration (CMC) are slightly higher while the amount of surface adsorption is slightly smaller for POEOl compared with those for POESt. Thermodynamic parameters of micelle formation derived from the temperature dependence of the CMC are also close to each other for the two surfactant species. These results demonstrate that the effect of double bond in the surfactant hydrocarbon chain on the surface activity is rather small at least for nonionic surfactant species with relatively long polyoxyethylene chain.
Disodium N,N’-dilauroylethylenediamine-N,N’-disuccinate (gemini surfactant, GS) and sodium N-lauroyl-N-methylamine succinate (monomeric surfactant, MS) form middle-phase microemulsions at an optimum mixing ratio with glycerol mono(2-ethylhexyl)ether (MEH) as a cosurfactant in the presence of NaCl. The solubilization capacity of microemulsion in the GS system is about twice as much as that of microemulsion in the MS system. This difference in solubilization capacity may be attributed to tight packing of GS molecules at a micro water-oil interface inside the microemulsion. With decreasing the salt content in water, the three-phase region consisting of excess water, oil phases and a middle-phase microemulsion shrinks and finally disappears, perhaps, at a tricritical point, at which three phases become simultaneously identical. The temperature dependence on the phase behavior of the microemulsions is also reported.
The phase behavior of commercial lipophilic poly(oxyethylene)-poly(dimethylsiloxane) copolymer (PEOS), Me3SiO(Si(Me)2O)x-(SiMe(C3H6(OCH2CH2)nOH)O)ySiMe3 (x= 50-100, y= 1-5, n= 7-15, HLB value= 5), in water and water + oil systems was investigated by phase study and small angle X-ray scattering (SAXS). The lipophilic PEOS forms a reverse hexagonal liquid crystal (H2) phase in water, and the H2 + excess water phase exists at a low concentration. The H2 phase changes to a reverse micellar cubic (I2) phase with addition of oil. The I2 structure is identified to the Fd3m space group by SAXS. An excess water phase is also coexisted with I2 phase beyond the solubilization limit of water in the I2 phase and a large amount of water can be dispersed in I2 phase as emulsion droplets. As a result, highly viscous or stable gel-emulsion over 96% water as the internal phase could be formulated.
An attempt was made to prepare ultrathin polystyrene films in the surfactant film formed on a mica substrate immersed in aqueous solution of tetradecyltrimethylammonium bromide (C14TAB), a cationic surfactant. Formation of polystyrene film was confirmed in the adsorbed C14TAB film on the basis of contact angle and IR spectrum measurements. Examination of the ultrathin film by AFM revealed that triangular polymer domains are formed on the substrate with all triangle sides aligning in the same directions at low concentrations of styrene (up to 43.6 mM). Use of sodium dodecysulfate (SDS) films adsorbed on a mica substrate also gave triangular polystyrene domains, the size of which increased with increasing polymerization time. The observed triangular structure was suggested to be formed under the influence of the hexagonal lattice of mica, independently of the properties of adsorbed surfactant films.
A liquid chromatography method with filament yarn as the stationary phase has been developed for studying the mechanism by which oily soils are removed from a fiber substrate with an aqueous surfactant micellar solution. We measured the retention volume of 1-phenylazo-2-naphthylamine (SY5) and l-phenylazo-2-naphthylphenol (SY14) as two kinds of oily soil model on either polyester or cellulosic filaments (the stationary phase) as a function of sodium dodecyl sulfate (SDS) concentration in the mobile phase. The oily soil elution volumes and capacity factors were affected with the micelle concentrations. The partition coefficients of the oily soils between SDS micelles and the fiber substrate, between the fiber substrate and water (non-micellar solution), and between SDS micelles and water (non-micellar solution) were determined with the chromatographic treatment involving micellar mobile phases. The standard free energy changes of the soils from the fiber substrate into the micelles (-ΔG°ms), from water onto the fiber substrate (-ΔG°sw), and from water into micelles (-ΔG°mw) were also calculated from the partition coefficient data. The -ΔG°sw values for SY5 and SY14 onto the polyester were larger than those onto the cellulosic filaments, whereas the -ΔG°ms values onto the cellulose larger than those onto the polyester filaments. Thus, it was shown thermodynamically that the oily soils re-deposit more readily on polyester than on cellulosic filaments. That is why it is more difficult to remove oily soils from polyester than from cellulosic filaments with SDS solutions.
Generally the degree of electrolytic dissociation of an aqua (protic solvent) is larger than that of a nonaqueous solvent (aprotic solvent). And the electric conductivity of an inorganic salt dissolved in a nonaqueous solvent is smaller than in an aqueous solution. Therefore the differential of electric conductivity was conspicuous because electric conductivity when dissolved with a solute is low in a nonaqueous solvent. The differential determination by conductometric titration of mixed solution of inorganic salts was possible in a nonaqueous solvent such as N,N-dimethylformamide (DMF). The simultaneous differential determination of nitrate and inorganic acid in solution was conducted by nonaqueous conductometric titration with sodium tetrahydroborate (STHB) in DMF. Inflection points appeared on conductometric titration curves of nitrate and inorganic acid solution in DMF, and were due to differences in reactivity and acidity. The inflection points indicated concentrations of nitrate and inorganic acid simultaneously. STHB and Al(NO3)3 reacted at a mole ratio of 1:3, and Co(NO3)2 reacted at 1:2. It was considered that the reaction mole ratio of STHB and nitrate was fixed by the valence of the metal ion. In order to investigate the reaction mechanism, ions in the DMF solution and precipitates were identified during titration by fourier transformation infrared spectroscopy (FT-IR), inductive coupling plasma emission spectrometry (ICP-AES) and the X-ray diffraction method (XRD). 10 % water in the sample solution did not interfere with the titration. The determination limit was 0.01-0.005 mol dm-3 with this method.