Band 49, Heft 6

In this paper, an improved method for the preparation of erucyl dimethyl amidopropyl betaine (EDAB) was provided. The synthesis conditions were investigated. N,N-dimethyl-N′-erucyl-1,3-propylenediamine was synthesized by the reaction of erucic acid with N,N-dimethyl-1,3-propylenediamine at 170°C for 7 h, and then the intermediate was reacted with sodium chloroacetate in the mixture of methanol and water (3:7 v/v) at 60°C. The product was obtained after 6 h. The compounds were confirmed by IR and 1 H-NMR. The properties of EDAB acid solution were also studied. The results indicated that viscosity of acid solution increased with decreasing hydrochloric acid concentration and was mainly controlled by surfactant concentration and temperature. The viscosity of an acid solution was maximum when the concentration of hydrochloric acid was at 15 wt%.

Sensitive and simple spectrofluorometric method has been developed and validated for the quantification of sulpiride in pure, commercial formulations, human plasma and urine in the presence of sodium dodecyl sulphate (SDS) surfactant micelle. The experimental parameters like buffer, surfactant type and volume were studied. A linear relationship was found between sulpiride concentration and fluorescence intensity in the range of 0.02 μg mL –1 –7.0 μg mL –1 containing 0.2 M sodium dodecyl sulphate with λ ex 292 nm and λ em 343 nm with a correlation coefficient of 0.9987. The limit of detection (LOD) and limit of quantification (LOQ) was found to be 1.9 × 10 –2 μg mL –1 and 5.9 × 10 –2 μg mL –1 respectively. The proposed method was successfully applied for the determination of sulphiride in pure and dosage form; the percentage recoveries agreed well with the label value. The effect of common excipients used as additive in pharmaceutical formulations was studied and no interferences was found. Similarly the effect of some common cations and compounds present in urine and plasma were also investigated and the method was found free of interferences. The method was further extended to the in-vitro determination of sulphiride in spiked human plasma and urine samples with percentage recoveries from 98.33%–99.75% and 95.67%–101.67% respectively. The results of the proposed method have been compared with the literature HPLC method and no significant difference was found between them.

The inhibition of gypsum precipitation by homo-, co-, and terpolymers has been examined in aqueous solution. It has been found that polymer performance as gypsum inhibitor depends upon polymer composition, type of comonomer, and functional groups. Results on the evaluation of polymers suggest that compared to co- and terpolymers, homopolymers containing carboxyl group are effective gypsum inhibitors. The impact of heat treatment (150°C to 240°C) on the performance of various homo-, co-, and teropolymers as gypsum inhibitors has also been investigated. It has been observed that all polymers lose performance to a varying degree when exposed to thermal treatment. Performance data on co- and terpolymers containing amido group show improved performance after heat treatment suggesting the formation of carboxyl group. Scanning electron microscopic investigations of gypsum crystals grown in the presence of polymers show that structures of these crystals are highly modified.

Adsorption kinetics of Cu(II) from aqueous solution by low cost chemically modified saw dust of Morus alba was investigated. The samples were characterized by FT-IR, EDS, BET surface area and Zeta potential technique. The surfaces contain carbonyl and hydroxyl functional groups which act as a binding sites for Cu(II) ion. Adsorption kinetics of Cu(II) was tested by first order kinetics, Elovich and parabolic diffusion kinetic equations which shows that adsorption is a diffusion controlled process. The rate of adsorption was high at high adsorption temperature. Thermodynamic parameters like ΔH°, ΔS° and ΔG° were calculated from the kinetic data.

Chemo-Autotrophic Activated Carbon Oxidation (CAACO) system was used for the treatment of tannery waste water. It employs activated carbon-immobilised sulphate reducing bacteria for the removal of dissolved organics in wastewater under oxidizing environment. The wastewater characteristics such as COD (1689 mg/L), BOD (377 mg/L), sulphate (915 mg/L) and sulphide (184 mg/L) were applied at an hydraulic loading rate of 0.7376 m 3 /m 3 /day and surface loading rate of 0.2438 m 3 /m 2 /day to CAACO reactor at 30°C and at atmospheric pressure. The removal of COD, BOD, sulphide and sulphate was 87%, 96%, 100% and 40% respectively after 2 hours of oxidation. The oxidation of dissolved organics in wastewater was accomplished by passing air at flow rate 3 L/min and at pressure 0.5 kg/cm 2 through CAACO reactor. The effect of variables COD loading, O 2 /COD, O 2 /(COD-BOD L ), COD/S 2 –, (COD-BOD L )/S 2 – and [(COD-BOD L ) i –(COD-BOD L ) e ]/S 2 – on rate and percentage removal of COD from tannery wastewater was determined.

Hexavalent chromium is a widespread environmental contaminant and a known human carcinogen. It is a very important to remove toxic Cr(VI) from industrial waste water. In human body Cr(VI) is reduced to Cr(III). Effective bio-molecule present in body contains a number of different functional groups. Kinetics of reduction of Cr(VI) by an important amino acid, glutamic acid in micellar media have been studied spectrophotometrically. Micellar media is a testing enviroment to establish the mechanistic paths of reduction of Cr(VI) to Cr(III). The catalyst and suitable surfactants enhance the reduction of Cr(VI).

We studied the mixing behavior of binary mixtures of alkylglycosides (CnGly); i.e. n-Octyl β-D-glucopyranoside, n-Decyl β-D-glucopyranoside and n-Decyl β-D-maltoside in combination with sodium laurate (NaL), and N,N-dimethyldodecylamine oxide in combination with NaL. The critical micelle concentration (CMC) data were obtained as functions of the composition based on equilibrium surface tension measurements. The cmc values with and without the addition of salt systems were then analyzed according to the regular solution model developed by Rubingh for mixed micelles. For the added salt systems, we applied Maeda's formulation for ionic/nonionic mixed micelles. For NaL/CnGly mixed systems, an increase in the hydrophilicity of the polar head group of CnGly resulted in a strong interaction between NaL and CnGly. In addition, introducing ionic species to the added salt systems stabilized the nonionic micelles.

Sodium sarcosinate, an anionic surfactant, is known as a methylated glycine derivative, that is synthesized in a one-step amidation reaction. In this work, to find out the best conditions, several experiments carried out. So, the highest yield was obtained at (303)°C, by gradual addition of sodium monochloro acetate to methylamine solution. The total reaction time is 6 hours. Based on data, and the plots of kinetics of the reaction, a second-order reaction equation was suggested for this synthesis reaction. The rate constant (κ), and the regression coefficient (R 2 ) were found as 0.0085 and 0.0934, respectively, which were in the best agreement with second-order reactions. According to the results, these data were applied for scale up laboratory to pilot phase. In addition, an industrial plant was suggested and designed.

Novel CO 2 H type gemini surfactants having semifluoroalkyl group (Rf-(CH 2 ) n -: Rf = C 4 F 9 , C 6 F 13 , C 8 F 17 and n = 2, 3) as hydrophobic group were successfully synthesized and their surface properties were studied. (Perfluoroalkyl)ethylmalonic esters were synthesized by the reaction of malonic ester with Rf(CH 2 ) 2 I using NaH as base in THF/DMF. (Perfluoroalkyl)propylmalonic esters were synthesized from allylmalonic ester, namely by the radical addition of Rf-I using AIBN as initiator, and reduction with Zn/AcOH. Those fluoroalkylated malonic esters were connected using Br(CH 2 ) s Br (s = 3, 4) to give dimeric tetraesters. Then, tetraesters were hydrolyzed using KOH/EtOH followed by decarboxylation in AcOH to afford CO 2 H type gemini surfactants. To study their surface properties, both surface tension-concentration and surface pressure-area isotherms were measured. As expected, COOH geminis showed one order of magnitude lower critical micellar concentrations (CMC) than that of conventional 1+1 type surfactant. In the surface pressure-area measurements, as length of fluoroalkyl increased, lift-off area (A L ) decreased, monolayers were clearly formed upon compression and the limited areas (A ∞ ) for C 6 F 13 and C 8 F 17 were smaller than twice of that of C 8 F 17 (CH 2 ) 2 COOH. Especially, COOH geminis having Rf = C 8 F 17 and -(CH 2 ) 3 - spacer showed the formation of solid phase monolayers, and the planar five membered ring-like structure was proposed.