The detergency of oily soil was studied from the viewpoint of control of textile/oil/water interface. In this review, the wetting of textile assemblies is chiefly discussed to study the sur-face free energies. It was made clear that such information can be obtained by (1) the exact consideration of geometrical structure of textile surface, and/or (2) the comparison of the results of other surface analyses, such as FT-IR, ESCA and so on, of the fabrics with those of flat films of same substrates whose surface free energies are known. The role of the control of textile surface on the removal, using for an example the soil-release finishing, is also discussed in terms of work of adhesion.
Ru/SiO2 catalysts were prepared by impregnating RuCl3·nH2O into silica in a series of solvents which can coordinate to metal ions and activating in hydrogen. The effects of the im-pregnation solvents on the Ru/SiO2 catalyzed hydrogenation of benzene were investigated. In the catalysts activated in hydrogen without calcination, cyclohexene yields were in the range of 9 to 25 depending on the complexing ability of the preparation solvents. When the impregnation solvents had strong coordination ability, the catalysts showed low cyclohexene yields. But when the impregnation solvents had weak coordination ability, the catalysts showed high cyclohexene yields. For instance, 2-aminoethanol and ethanol gave the catalysts showing the highest and lowest cyclohexene yields respectively. When the catalysts were activated in hydrogen after cal-cination, all the catalysts showed almost the same cyclohexene yields in spite of the different kinds of impregnation solvents. The visible spectra of the catalyst preparation solutions and thermogravimetric analyses of non-calcined catalysts indicated that differences between the catalysts with and without calcination is due to inclusion of impregnation solvents in non-calcinated catalysts after activation.
The surface adsorbability of a cationic surfactant on nylon 6 fibers grafted with acrylic and methacrylic acids was studied by measuring the ζ-potential of the fibers in an aqueous solution of the surfactant, N-dodecylpyridinium bromide (DPB). The amount of adsorbed DPB per unit area of the fibers was calculated from the ζ-potential value. With increase in DPB concentration, the ζ-potentials of the ungrafted and the grafted fibers changed from negative to positive in sign and the amount of DPB adsorbed increased. Thus possibly, electrostatic and van der Waals forces between the fibers and cationic surfactant may contribute to surface adsorbability. The amount of DPB adsorbed decreased with increase in the degree of grafting. The free energy of adsorption (ΔG) of DPB on the fibers was calculated from the equation of Ottewill-Watanabe. With increase in the degree of grafting, the negative value of ΔG decreased. The positive entropy of adsorption of the ungrafted and the grafted fibers indicates entropic interactions (the formation of hydrophobic bonds) to possibly be important as the driving force for the adsorption of DPB on the surfaces of the fibers. Based on the above findings, the surface adsorbability of the cationic surfactant on the grafted fibers is concluded to be less than that on ungrafted fibers since the water-soluble polymer layer was formed at fiber surfaces by grafted polymer chains.
The authors previously reported that polyunsaturated fatty acids having 1, 4-diene structure can be easily conjugated at ordinary temperature using iodine as a photosensitizes. This paper describes the optimum conditions for the iodine-sensitized conjugation of methyl linoleate under irradiation with a 100W high-pressure mercury lamp and the mechanism involved. A nonpolar solvent such as petroleum ether was used in this reaction. The optimum conditions of the reaction were as follows : approximately 0.1% of the amount of iodine added; 10% of the concentration of linoleate; room temperature; and irradiation for 1.5h with a mercury lamp.Under these conditions, methyl linoleate was converted to conjugated dienoates in yields of approximately 80% along with small quantities of methyl trans-octadecenoates and polymers. No positional transfer selectivity of double bonds could be detected at all. The conjugated pro-ducts were present in equal amounts as a mixture of methyl 9, 11- and 10, 12-octadecadienoates (the ratio of the cis, trans and trans, trans forms was 3 : 7). It is considered that iodine atoms react only with the 1, 4-diene system in this iodine-sensitized conjugation to first form a bridged iodoalkyl radical intermediate which is subsequently converted mainly into cis, trans conjugated forms accompanied by a shift of hydrogen and finally the geometrical isomerization equilibrium mentioned above is attained.
In the previous paper, we reported the optimum conditions for the iodine-sensitized conjugation of methyl linoleate and its reaction mechanism. This paper discusses isomerization arising from irradiation with a 100W high-pressure mercury lamp using methyl linolenate with a 1, 4, 7-triene structure. Conjugated diene-trienoates and small amounts of conjugated trienoates are formed in this reaction. Slightly milder conditions than in methyl linoleate are suitable for the formation of conjugated diene-trienoates. The reaction conducted at room temperature using a sample with a concentration of 10 to 20% adding approximately 0.1% of iodine to a nonpolar solvent such as petroleum ether by irradiation for 46h is considered optimum. To obtain conjugated trienoates mainly, however, milder conditions such as no more than 0.03% iodine should be used. Under such conditions, the amounts of conjugated compounds were as much as about 70% (conjugated diene-trienoates 5562%; conjugated trienoates 815%) of the reaction products. This sensitized isomerization proceeds in the same way as indicated in the previous report and double bonds shift only in the direction of the conjugation.
Polyunsaturated fatty acids and their derivatives having the 1, 4-diene structure are conjugated easily at ordinary temperature in the presence of iodine by photoirradiation. The side reaction was investigated in detail in the present study. Addition of excess iodine to a mixture of monoenes and polyenes caused formation of petroleum ether-insoluble polymers from polyene compounds while monoene compounds remained unchanged under these conditions. Thus, polyene compounds can be selectively removed from a mixture of monoenes and polyenes by the iodine-sensitized method. An example of the purification of monoene compounds is presented below. Methyl esters of tsubaki fatty acids (C16 9.8%; C16 : 1 trace; C18 2.8%; C18 : 1 82.9%; C18 : 2 4.1%; C18 : 3 0.4%) were treated by the urea adducts method. The iodine-sensitized method was carried out on the mother liquor followed by rectification and methyl oleate with a purity of 99.6% was obtained in yields of 66%. Since this method can be also carried out in the sunlight, it is suited for conducting large scale reactions.