Band 57, Heft 4

The glucose-based cationic-nonionic surfactant (GCN) and Ag-SiO 2 nanocomposites were prepared and the interfacial tension and foaming properties were investigated. Besides, the structures of GCN were confirmed by Fourier transform infrared spectrometer and 1 H nuclear magnetic resonance. The synthesized Ag-SiO 2 was characterized by X-Ray diffraction and transmission electron microscope. The performance evaluations indicated that the GCN/Ag-SiO 2 mixtures could effectively decrease the interfacial tension to an order of 10 -3 mN/m, had excellent foaming properties, and thus enhanced the oil recovery. The experimental data demonstrated that the introduced Ag-SiO 2 could endow the GCN surfactant with outstanding performances.

A series of alkyl polyglycoside polyoxypropylene ethers (APGPE-n) has been prepared by propoxylation of alkyl polyglycoside (APG). The structure, the physical and application properties of alkyl polyglycoside polyoxypropylene ethers were investigated and compared with the APG raw material to highlight the effect of propylene oxide (PO) addition on the chemo-physical properties of the surfactants.

The equilibrium and dynamic surface properties and the adsorption behavior of alkyl glycosides and their derivatives alkyl glycoside tartarates at the air/water solution interface were investigated. The equilibrium surface tension and the critical micelle concentration were measured by Wilhelmy plate method and the dynamic surface tension was measured by maximum bubble pressure method. The data display that the surface tension of the alkyl glycoside tartarate surfactants was significantly reduced (24 mN m –1 ) compared to that of alkyl glycosides, which indicated that alkyl glycoside tartarates have a strong activity at the air/water interface. The study also found that the alkyl glycoside tartarates reach the meso-equilibrium region faster, adsorb more easily at the interface, and have a lower adsorption energy. In addition, the study further confirmed the existence of energy potential barrier.

Oxidation of cyclohexanol, a six membered cyclic alcohol, by Ce(IV) is a slow-moving reaction. Therefore, it was investigated in a comparative study whether the oxidation rate can be increased by adding trace amounts of Ru(III) and Ir(III) metal catalysts in anionic (sodium dodecyl sulfate) and cationic (cetylpyridinium chloride) micellar media. The kinetics of the oxidation of cyclohexanol with Ce(IV) in acidic medium has been studied spectrophotometrically at 28°C under pseudo 1st order reaction condition. Based on the spectroscopic evidence the mechanisms for the reactions taking place in the presence of these metal catalysts were proposed.

Cationic flavor microcapsules were synthesized with tetradecyl allyldimethyl ammonium bromide (TADAB) as main shell material by emulsion polymerization. Methyl methacrylate (MMA), polyoxyethylene alkyl ether, and pentaerythritol tetraacrylate (PETRA) were applied as co-monomer, emulsifier and crosslinking agent, respectively. The polymerization reaction was proved by Fourier transform infrared spectroscopy (FTIR). The images of scanning electron microscope (SEM) illustrated that the flavor microcapsules were spherical under the optimum preparation condition. The particle size distribution of the flavor microcapsules was between 2 μm–10 μm and the zeta potential was +39.2 mV at pH 4.48. The thermogravimetric analyses indicated that the volatility of the flavor was effectively suppressed and the thermal stability was improved as the flavor was encapsulated in the microcapsules. When the flavor microcapsules were dispersed in an aqueous surfactant solution containing 20 w% polyoxyethylene alkyl ether, approximately 18% of the flavor was released within the first 30 h, but no flavor was released after 30 h. In an open beaker, the flavor retention of the microcapsules was 56.57% compared to 16.76% of flavor microcapsules broken in advance with mortar. The flavor microcapsules are very well suited for use in detergents or soaps, as they suppress the volatilization of the flavor in case of mechanical breakage and release the flavor well.

The PDMC colloid (PDMC = poly(methacryloyloxyethyl trimethylammonium chloride) is a polyquaternary ammonium salt that is homopolymerized by methacryloyloxyethyl trimethyl ammonium chloride (DMC). The polymerization was carried out in aqueous solution, which was characterized by one-off feeding, a redox initiator system and segmented temperature control. The molecular structure of PDMC was characterized by IR spectroscopy, 1 H-NMR, thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The intrinsic viscosity η of PDMC was determined with an Ubbelohde viscometer and the molecular weight of PDMC was calculated from the intrinsic viscosity. The antistatic property of PDMC for polyester, acrylic and cotton fabrics was investigated. A flocculation test was performed in a waste water system simulated with diatomaceous earth. The results showed that PDMC has an excellent antistatic property for polyester as well as acrylic fabrics, which is durable. Compared to the alkaline state, PDMC has the better flocculation effect under acidic and neutral conditions.

A surfactant mediated cloud point extraction (CPE) has been developed to remove color from wastewater containing toxic Eosin Y dye, using Triton X-114 (TX-114) as nonionic surfactant. Most of the dye molecules become solubilized in the coacervate phase leaving dilute phase free of dyes. The effects of surfactant concentration, temperature and salt concentration on the extraction yield of the dye have been investigated and the optimum conditions were obtained for the removal of toxic Eosin Y. It was found that phase separation was complete and the recovery of Eosin Y was very effective in the presence of NaCl as an electrolyte. The results showed that up to 20 ppm of Eosin Y, more than 97% can quantitatively be removed by cloud point extraction procedure in one single extraction at optimum conditions. In addition, it was observed that at a dye concentration of 5 ppm and a Triton X-114 concentration of 2.75 wt%, 99% of the dye eosin Y can be removed. At 50°C, a dye removal of 96.8%–99% can be achieved with a higher dye concentration of up to 25 ppm when 2.75wt% Triton X-114 and 0.02 M salt (NaCl) are present. It is concluded that the cloud point extraction techniques for the dye removal may be an alternative to the present dye removal processes.

In the present study, a series of gemini surfactants with amide group (abbreviated as (m = 12–16, n = 1, 2)) were synthesized. Complementary characterizations of their structure by spectroscopic methods such as IR, 1 H-NMR, MS, and investigations of their properties such as measurements of the conductivity, the surface tension, the foaming and the emulsifying capacity were performed. The results showed that almost all products had a Krafft point below 0°C, except the C 16 –(EO)–E–C 16 surfactant. Furthermore, the equilibrium surface tension (γ CMC ) of the synthesized Gemini surfactants at the CMC was determined. For C 12 -(EO)-E-C 12 it is 41.0 mNm –1 , for C 14 -(EO)-E-C 14 43.8 mNm –1 , for C 16 -(EO)-E-C 16 46.7 mNm –1 and for C 12 -(EO) 2 -E-C 12 41.9 mNm –1 . The addition of the inorganic salt NaBr could significantly increase their surface activities. In addition, the thermodynamics of the micelle formation between 25°C–45°C was investigated. The results indicated that the micellization process was spontaneous. Finally, the obtained Gemini surfactants proved to be good emulsifiers, while their foaming properties were influenced by the self-coiling of the associated long alkyl tails.

In this study, 16 acylamino acid surfactants carrying glycine, alanine, valine, and leucine residues were synthesized in the desired yields in an environmentally friendly manner using vegetable oils and beef tallow as acyl donors. The quantitative compositional analyses of these surfactants were performed using HPLC/MS, and the results were consistent with the fatty acid compositions of the corresponding oils and tallow. Their CMC values, determined by surface tension measurements, generally increased with decreasing amino acid hydrophobicity and average chain lengths. Furthermore, all products showed a better detergency performance than sodium alcohol ether sulfate (NaAES) and the sodium soap derived from oils and tallow, suggesting that they can be potentially applied for the formulation of personal care products.