Volume 45, Issue 2

The impact of heat treatment on the performance of various polymers as ferric ions stabilization agents in an aqueous system at pH 7.00, 23 °C has been investigated. The polymers evaluated include: (a) homo-polymers of acrylic acid, methacrylic acid, maleic acid, 2-acrylamido-2-methylpropane sulfonic acid, sulfonated styrene; (b) co-polymers of acrylic acid: 2-acrylamido-2-methylpropane sulfonic acid and maleic acid: sulfonated styrene, and (c) ter-polymers of acrylic acid: 2-acryalamido-2-methylpropane sulfonic acid: sulfonated styrene, acrylic acid: methacrylic acid: t-butylacrylamide, and acrylic acid: 2-acrylamido-2-methylpropane sulfonic acid: t-butylacrylamide. It has been found that all polymers lose performance to a varying degree when exposed to thermal treatment (150 °C, 200 °C, 240 °C, 20 hr). The performance data collected before and after thermal treatment suggest that sulfonated styrene containing co- and ter-polymers are better ferric ions stabilization agents than the co- and ter-polymers containing 2-acrylamido-2-methylpropane sulfonic acid and t-butylacrylamide. In addition, it has been found that heat treatment exhibits positive influence on the performance of homo-polymer of 2-acrylamido-2-methypropane sulfonic acid. The results have been explained in terms of loss of 2-acrylamido-2-methylpropane sulfonic acid and t-butylacrylamide in the co- and ter-polymers during thermal treatment.

Anionic Gemini surfactants having two phosphate head groups and two decyl head groups were prepared in good yield. These surfactants were prepared by two step process. (i) Preparation of decyl phosphate from pyrophosphoric acid and decanol. (ii) Preparation of bis-phosphoric acid from decyl phosphate, (CH 3 ) 4 NOH and different spacers by using acetonitrile as solvent. The synthesized surfactants structures were verified by FT IR, and 1 H NMR spectroscopy. The physical and performance properties like surface tension and interfacial tension, foaming, wetting and emulsion stability of disodium salts of bis-phosphoric acids were also evaluated. The effects of the spacers on the properties were analyzed. It was found that properties were significantly influenced by slight variation of spacers.

Four of new tin(IV) compounds derived from aziridine and azepane substituents have been synthesized and characterization by elemental microanalysis, atomic absorption, FT-IR and 1 H-NMR spectroscopy. These tin-derived compounds exhibited biocidal activities on four different microorganisms: Escherichia coli, Staphylococcus aureus, Candida albicans and Aspergillus niger. The use of common and effective biocides depends on the surfactant molecules. On this basis, surface tension measurements were used to determine the critical micellar concentration (cmc), the minimum average area per surfactant molecule (A min ) and the surface excess concentration (Γ ∞ ). A direct relationship has found between the antimicrobial efficacy and Γ ∞ .

In view of imperfections of conventional anionic and nonionic surfactants used for enhanced oil recovery, especially the characteristics of high salinity and high Calcium/Magnesium for sea water flooding, a new novel displacement agent suitable for sea water flooding was synthesized through alkoxylation, epoxidation, sulfonation reaction with fatty alcohol as core. The structure of the product was characterized by IR. The properties of the product, including salt tolerance, temperature resistance etc. were evaluated. At 70 °C, when the concentration of this surfactant is 0.3 %, the interfacial tension between simulated water solution and Bohai1A-4 well crude reaches 10 −3 mN/m order, the salt tolerance reaches 50 000 mg/L, the resistance to calcium and magnesium reaches 2000 mg/L. The laboratory physical simulation test shows that the binary complex system (polymer + surfactant) can enhance the recovery ratio by 17.9 %, while better synergistic effect of the system is obtained.

The solid copper(II) soaps derived from Mustard oil and Soyabean oil and their complexes with ligands containing nitrogen and sulphur atoms like urea, thiourea and 2-amino-6-chloro benzothiazole have been synthesized and characterised by elemental analysis, IR, NMR, ESR spectroscopy and magnetic moment studies. From the analytical data, the stoichiometry of the complexes have been observed to be 1: 1 (metal: ligand). The magnetic moment studies suggest the dimeric nature of the complexes. IR, NMR and ESR spectral details confirm that complexation has taken place successfully. The results indicate that the complexes possess elongated octahedral geometry. Conductometric studies suggest that the soaps and complexes are non-electrolytic in nature. The fungi toxicities of these ecofriendly and biodegradable soaps and complexes have been investigated.