Impact of Free Fatty Acids and Phospholipids on Reverse Micelles Formation and Lipid Oxidation in Bulk Oil

Association colloids such as phospholipid reverse micelles could increase the rate of lipid oxidation in bulk oils. In addition to phospholipids, other surface active minor components in commercial oils such as free fatty acids may impact lipid oxidation rates and the physical properties of reverse micelles. In this study, the effects of free fatty acids on changes in the critical micelle concentration (CMC) of 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC) in stripped corn oil (SCO) were determined by using the 7,7,8,8-tetracyanoquinodimethane solubilization technique. Different free fatty acids including myristoleic, oleic, elaidic, linoleic and eicosenoic were added at 0.5 % by wt along with the DOPC into the bulk oils. There was no significant effect of free fatty acids with different chain length, configuration and number of double bonds on the CMC value for DOPC in bulk oil. However, increasing concentrations of oleic acid (0.5 to 5 % by wt) caused the CMC value for DOPC in bulk oils to increase from 400 to 1,000 μmol/kg oil. Physical properties of DOPC reverse micelles in the presence of free fatty acids in bulk oils were also investigated by the small angle X-ray scattering technique. Results showed that free fatty acids could impact on the reverse micelle structure of DOPC in bulk oils. Moreover, free fatty acid decreased pH inside reverse micelle as confirmed by the NMR studies. The oxidation studies done by monitoring the lipid hydroperoxide and hexanal formation revealed that free fatty acids exhibited pro-oxidative activity in the presence and absence of DOPC. Different types of free fatty acids had similar pro-oxidative activity in bulk oil.     

3,4-二氨基呋咱的两种催化合成新方法

研究了胶束催化和负载型固体碱催化的3,4-二氨基乙二肟分子内脱水合成3,4-二氨基呋咱的两种新方法。负载型固体碱催化下,考察了反应温度、压力、物料配比等对反应收率的影响,较佳的反应条件为:150℃,0.7 MPa,3,4-二氨基乙二肟(DAG)与负载型固体碱催化剂(cat.)和H2O的质量比为13.512.5,反应时间4 h,该条件下收率为91.2%。催化剂分离后重复使用五次以上,催化活性无明显下降。与氢氧化钾催化的反应相比,催化剂用量少,反应温度及压力低,收率高,易分离。胶束催化下,阴、阳离子表面活性剂在大于临界胶束浓度下均具有良好的催化效果,升高压力不利于反应进行。110℃,DAG与KOH、H2O及十二烷基苯磺酸钠(SDBS)的质量比为11.37.10.02条件下,常压反应10 h,反应收率为46.0%。     

Synthesis and Characterization of Multifunctional Surfactants in Oil-Field Protection Applications

A series of cationic surfactants was prepared using economical raw materials. The chemical structures of the prepared compounds were confirmed using elemental analysis, FTIR and ¹H-NMR spectra, and melting point determination. The synthesized surfactants were evaluated as oil-field protective additives. In this regard, several surface properties of the synthesized surfactants were studied including surface tension, critical micelle concentration, effectiveness, efficiency, maximum surface excess and minimum surface area. The results obtained from the surface activity measurements were correlated to their chemical structures. The emulsification power measurements for solutions of these surfactants showed their low emulsifying tendency towards paraffin and crude oil. The synthesized surfactants also exhibited high biocidal activity towards gram-positive and gram-negative bacteria and fungi. This activity was increased by increasing the hydrophobic chain length. The corrosion inhibition measurement of these surfactants for mild steel alloys in acidic media using a weight loss technique showed good protection of mild steel alloys against acidic environments. These properties qualify the synthesized compounds as economical oil-field protective additives.

A Kinetic and Mechanistic Study on the Oxidation of Hydroxy Acids by <Emphasis Type="Italic">N</Emphasis>-Bromophthalimide in the Presence of a Micellar System

The kinetics of oxidation of some α-hydroxy acids viz. Tartaric acid (TA) and Malic acid (MA) by N-bromophthalimide (NBP) were studied in the presence of a cationic surfactant, cetyltrimethylammonium bromide (CTAB), in perchloric acid medium at 313 K. The oxidation of TA and MA by N-bromophthalimide in the presence of CTAB is faster than in the absence of surfactant. The rate of oxidation of hydroxy acids was found to be in the order: TA > MA. First order kinetics with respect to NBP was observed in the oxidation of both hydroxy acids. The kinetics results indicate that the first order kinetics in hydroxy acids at lower concentrations tends towards a zero order at its higher concentrations. Inverse fractional order in [H⁺] and [phthalimide] were noted throughout its tenfold variation. With a progressive increase in [CTAB], the rate of reaction increased, reaches a maximum value and then constancy in k _Ψ was observed. Variation of [Hg(OAc)₂] and ionic strength (μ) of the medium did not bring about any significant change in the rate of reaction. The applicability of different kinetic models viz. the Piszkiewicz cooperative model, the Raghvan and Srinivasan model, and the Menger–Portnoy model were tested to explain the observed micellar effects. The effect of [CTAB] on the activation parameters was explored to rationalize the micellar effect. The values of rate constants observed at four different temperatures were utilized to calculate the activation parameters. A suitable mechanism consistent with the experimental findings has been proposed. The index of cooperativity and the micelle binding constant have been calculated.

酶在反胶束体系中应用

该文介绍反胶束和反胶束酶体系结构,动力学模型,并着重介绍其应用范围,并对今后反胶束应用进行展望。     

Gelation of Mixed Gels Containing κ-Carrageenan and Skim Milk Components

ABSTRACT: The gelation characteristics of mixed gels containing κ-carrageenan and skim milk or milk fractions (skim milk permeate or retentate) obtained by ultrafiltration were examined. Increasing the skim milk solids content of mixtures containing carrageenan increased setting temperatures and gel strength. The milk proteins contributed to gel strength but did not influence the setting temperature of mixtures. The binding of denatured whey proteins to casein micelles affected gel network formation of milk-carrageenan mixtures containing 10% milk solids. Network formation in mixed gels containing carrageenan and milk or milk fractions was initiated by the carrageenan component and dictated primarily by the ionic content of the mixtures.     

Extraction of immunoglobulin-G from colostral whey by reverse micelles

Separation of immunoglobulin G (IgG) from the other colostral whey proteins was carried out by reversed micellar extraction. The colostral whey was diluted to 5 times its original volume with 50 mM phosphate buffer at pH 6.35 containing 100 mM of sodium chloride. The aqueous solution was then mixed with an equal volume of isooctane containing 50 mM bis-(2-ethylhexyl) sodium sulfosuccinate (AOT), and shaken at 200 rpm and 25 degrees C for 10 min. After extraction, the mixture was separated to the aqueous phase and the reversed micellar phase by centrifugation. This procedure extracted most of the non-IgG proteins to the reversed micellar phase and recovered more than 90% of the IgG in the aqueous phase. The IgG in the aqueous phase had a purity of 90%, and still possessed immunological activity. AOT was not detectable in the aqueous phase.     

低自由水钻井液体系

基于对钻井液中自由水流动状态的研究,研制了自由水络合剂,其能有效络合钻井液中的自由水,提高自由水进入地层的毛管阻力,减少滤液侵入地层的量和深度;同时络合剂络合自由水后形成特殊的分子胶束,能形成致密的低渗透封堵膜,有效封堵孔喉和微裂缝,提高地层承压能力,降低钻井液密度。构建了低自由水钻井液体系,CST毛细管吸水实验、岩心自吸水实验和自由水含量测定均证实该体系具有较好的络合自由水的能力,能有效减少钻井液中液相向地层的侵入量。现场应用结果表明,该体系具有良好的流变性、润滑性及抑制性,可有效解决井壁稳定性问题,且能有效提高地层承压能力、降低钻井液密度、提高机械钻速、缩短钻井周期。图6表5参18     

耐温抗盐甜菜碱表面活性剂的表征及性能研究

本文合成了一种耐温抗盐表面活性剂,通过红外光谱、拉曼光谱以及元素分析考察了该表面活性剂的结构,并研究了其表界面活性和乳化性能。研究结果表明：所合成产物与目标产物———羟磺基甜菜碱一致;羟磺基甜菜碱溶液具有较低的表面张力,临界胶束浓度为8.099×10^-5 mol/L;在0.5～3.0 g/L浓度范围内,羟磺基甜菜碱溶液与原油间的界面张力（稳定值）均能够达到超低,且在30℃～80℃较宽的温度范围内均能达到超低界面张力;此外羟磺基甜菜碱还具有一定的乳化能力。羟磺基甜菜碱作为一种具有良好应用前景的表面活性剂,有望应用于国内外高温高盐油藏。     

四臂双亲性PEMA-b-PMAA嵌段共聚物的合成

由2-溴异丁酰溴和季戊四醇反应合成了四臂引发剂,以CuCl为催化剂,N,N,N′,N″,N″-五甲基二亚乙基三胺（PMDETA）为配体,在N,N-二甲基甲酰胺（DMF）中分步引发甲基丙烯酸乙酯（EMA）和甲基丙烯酸叔丁酯（tBMA）进行原子转移自由基聚合（ATRP）,得到了四臂型嵌段共聚物PEMA-b-PtBMA。改变...