离子型表面活性剂对荧光素酶和α-脂肪酶的影响

In order to study the effects of ionic surfactants on bacterial luciferase, the cationic surfactant dodecyltrimethylammonium biomide (DTAB) and anionic surfactant sodium dodecylsulfate (SDS) were chosen. For comparison with bacterial luciferase, α-amylase was used since these two enzymes have similar electrostatic potential and charged active sites. After the enzymes were treated with the surfactants, the catalytic properties of bacterial luciferase and α-amylase were assayed, and fluorescence spectroscopy and circular dichroism (CD) were used to analyze the alteration of the protein structure. The results showed that when the DTAB concentration was low, the cationic surfactant DTAB enhanced the enzymatic activities of bacterial luciferase and α-amylase. On the other hand, the anionic surfactant SDS did not alter the enzymatic activity. The main interaction of cationic surfactant DTAB and the negatively charged surface of the proteins was the ionic interaction, which could alter the environment for the enzyme to work when the DTAB/enzyme molar ratio was low. However, at high cationic surfactant concentration, the ionic interaction and hydrophobic interaction might destroy the secondary and tertiary structures of the proteins, leading to the loss of enzymatic activities.     

Analysis of ionogenic surfactants by HPLC with ion-pair extraction detector

A technique for developing a selective and highly sensitive detection method was studied, which responds to particular ionogenic surfactants using a system of connecting the post-column reaction detector with a high performance liquid chromatograph (HPLC). HPLC conditions used for the separation were: column packing and size, TSK-LS410 (5μ) and 6 mm i.d. × 250 mm; mobile phase, a mixture of methanol, water, sodium perchlorate and phosphoric acid. A Technicon AutoAnalyzer II system was used as the post-column reaction detector. Orange II was used to form the hydrophobic ion-pair complexes for cationic and amphoteric surfactants, and Methylene blue for anionic surfactants. By this method, cationic, amphoteric and anionic surfactants were easily identified in the chromatograms. The analytical results of their homolog distributions were in good agreement with those obtained by conventional gas chromatographic (GC) methods.     

Interaction of DNA with Cationic Gemini Surfactant Trimethylene-1, 3-bis （dodecyldimethyl-ammonium bromide） and Anionic Surfactant SDS Mixed System

The interaction of DNA with cationic gemini suffactant trimethylene-1,3-bis （dodecyl dimethyl-ammonium bromide） （12-3-12） and anionic surfactant sodium dodecyl sulfate （SDS） mixed system has been investigated by measuring the fluorescence, zeta potential, UV-Vis spectrum, and circular dichroism. In the absence of SDS, owing to the electrostatic and hydrophobic interactions, 12-3-12 forms micelle-like structure on the DNA chain before the micellization in bulk phase. For the mixed system of 12-3-12 and SDS, the negative charges on SDS can compete against DNA to bind with cationic 12-3-12 because of the stronger interaction between oppositely charged surfactants, and thus, the catanionic mixed micelles are formed before the formation of DNA/12-3-12 complexes. There-after, the positive charges on the mixed micelles bind with DNA, and thus, the change of the zeta potential from negative to positive is distinctly different from the system without SDS. Meanwhile, the existence of SDS postpones the exclusion of ethidium bromide （EB） from DNA/EB complexes. The conformation of DNA undergoes a change from native B-form to chiral ψ-phase as binding with 12-3-12 process. Upon adding SDS to the DNA/12-3-12 complex solution, however, DNA is released to the bulk and the ψ-phase returns to B-form again.     

连接基团与尾链长度对阳离子Gemini表面活性剂与阴离子聚电解质复合物影响的分子动力学模拟

Interaction of anionic .polyelectrolyte with cationic, gemini surfactant has been investigated by coarse-grained molecular dynamics simulation. Polyelectrolyte facilitates the oppositely charged ionic surfactants to aggregate by suppressing the electrostatic repulsion between ionic head groups leading to the formation of micellarcomplex. With addition of surfactant, the conformation of polyion chain changes from stretched to random coiled to spherical, and at the same time more free micelles are formed by surfactants in mixtures. Increasing the length ofspacer or tail chain in gemini surfactant will weaken its interaction with polyelectrolyte and simultaneously strengthen its tendency to self-assemble. The simulation results are consistent with experimental observations and reveal that the electrostatic interaction plays an important role in the interaction of polyelectrolyte with gemini surfactant.     

偶联阳离子表面活性剂和常用阴离子表面活性剂混合溶液的相分离和微观结构

The properties of aqueous two-phase system (ATPS) of mixed solution containing gemini cationic surfactant trimethylene-l,3-bis(dodecyldimethyl ammonium) bromide (12-3-12, 2Br-) and traditional anionic surfactant sodium dodecyl sulfate (SDS) with or without added salt have been studied. An ATPS is formed in a narrow region of the ternary phase diagram different from that of traditional aqueous cationic-anionic surfactant systems. In ATPS region, the lowest total concentration of surfactants varies with the mixing ratio of geminis to SDS. Photographs obtained from freeze-etching, negative-staining and transmission electron microscopy show that the microstructures of two phases are different from each other. Micelles and vesicles can coexist in a single phase. The addition of salts can change the phase diagram of ATPS. Furthermore, the added salts promote the aggregation of rod-like micelles to form coarse network structure that increase the viscosity of solutions. The negative ions of the added salts are the determining factor.     

亲和反胶团选择性萃取分离酵母乙醇脱氢酶

The reversed micelles were formed with cationic cetyltrimethylammonium bromide (CTAB) as surfactant and n-hexanol as cosolvent in the CTAB (50mmol L-1)/hexanol (15% by volume)/hexane system. Cibacron Blue 3GA (CB) as an affinity ligand in the aqueous phase was directly introduced to the reversed micelles with electrostatic interaction between anionic CB and cationic surfactant. High molecular weight (Mr) protein, yeast alcohol dehydrogenase (YADH, Mr = 141000) from baker's yeast, has been purified using the affinity reversed micelles by the phase transfer method. Various parameters, such as CB concentration, pH and ionic strength, on YADH forward and backward transfer were studied. YADH can be transferred into and out from the reversed micelles under mild conditions (only by regulation of solution pH and salt concentration) with the successful recovery of most YADH activity. Both forward and backward extractions occurred when the aqueous phase pH>pI with electrostatic attraction between YADH and CTAB. Th     

Interaction of ciprofloxacin hydrochloride with sodium dodecyl sulfate in aqueous/electrolytes solution at different temperatures and compositions

Interactions of ciprofloxacin hydrochloride(CPFH) with sodium dodecyl sulfate(SDS) were investigated by conductivity measurement in H_2O/electrolyte solutions(NaCl, Na_2SO_4 Na_3PO_4) over 298.15–318.15 K temperature range(with 5 K interval) considering the human body temperature. In all cases, two critical micelle concentrations(c~*) were observed which are increased in the presence of drug and decreased in the presence of salts enunciating the presence of interaction amongst the studied components. For(CPFH + SDS) system in the presence of salt, the c~*values at 303.15 K and I = 0.50 mmol·kg~(-1) followed the order: C_(NaCl)C_(Na_2SO_4)C_(Na_3PO_4). The ΔG_(1,m)~0 and Δ G_(2,m)~0values are found to be negative for all systems that show that the micellization process is thermodynamically spontaneous. For(CPFH + SDS) system in water, the Δ H_m~0 Δ S_m~0 values reveal that the micellization processes is both entropy dominated in almost all cases. In the occurrence of electrolytes, Δ H_m~0 and Δ S_m~0 values indicate that micellization processes are both entropy enthalpy restricted at upper temperature but it becomes totally entropy dependent at higher temperature. The higher positive Δ S_m~0 values indicate the enhanced hydrophobic interaction in presence of salts. The enthalpy-entropy compensation was determined from the linear relationship betweenΔ H_m~0 and Δ S_m~0 values in every state. Different transfer energies as well as compensation temperature and intrinsic enthalpy were also evaluated and the behaviors were comparable to other biological system.     

The adsorptive properties of UiO-66 towards organic dyes: A record adsorption capacity for the anionic dye Alizarin Red S.

In order to decisively determine the adsorption selectivity of zirconium MOF(UiO-66) towards anionic versus cationic species, the adsorptive removal of the anionic dyes(Alizarin Red S.(ARS), Eosin(E), Fuchsin Acid(FA)and Methyl Orange(MO)) and the cationic dyes(Neutral Red(NR), Fuchsin Basic(FB), Methylene Blue(MB),and Safranine T(ST)) has been evaluated. The results clearly reveal a significant selectivity towards anionic dyes. Such an observation agrees with a plethora of reports of UiO-66 superior affinity towards other anionic species(Floride, PO_4~(3-), Diclofenac sodium, Methylchlorophenoxy-propionic acid, Phenols, CrO_4~(2-), SeO_3~(2-), and AsO_4~-). The adsorption process of ARS as an example has been optimized using the central composite design(CCD). The resultant statistical model indicates a crucial effect of both pH and sorbent mass. The optimum conditions were determined to be initial dye concentration 11.82 mg.L~(-1), adsorbent amount 0.0248 g, shaking time of 36 min and pH 2. The adsorption process proceeds via pseudo-second order kinetics(R~2= 0.999). The equilibrium data were fit to Langmuir and Tempkin models(R~2= 0.999 and 0.997 respectively). The results reveal an exceptional removal for the anionic dye(Alizarin Red S.) with a record adsorption capacity of400 mg·g~(-1). The significantly high adsorption capacity of UiO-66 towards ARS adds further evidence to the recently reported exceptional performance of MOFs in pollutants removal from water.     

1,2-环己二醇的焓和热容数据研究

The thermodynamic properties of different geometric structures of 1,2-cyclohexanediol which were rarely reported in literature, such as combustion enthalpy, formation enthalpy, melting enthalpy and heat ca-pacities, were determined by NETZSCH DSC 204 Scanning Calorimeter. The relationship between the melting point and the composition for the mixture system of cis-1,2-cyclohexanediol and trans-1,2-cyclohexanediol was investigated and corresponding phase diagram was obtained. "The melting enthalpies of both cis-1,2-cyclohexanediol and trans-1,2-cyclohexanediol are 20.265kJ·mol-1 and 16.368kJ·mol-1 respectively. The standard combustion enthalpies of cia- and trans-1,2-cyclohexaneddiol were determined by calorimeter. They are respec-tively -3507.043 kJ·mol-1 and - 3497.8 kJ·mol-1 at 298.15 K.The standard formation enthalpies are respectively 568.997 kJ·mol-1 and 578.240 kJ·mol-1 for cia- and trans -1,2-cyclohexaneddiol.     

Synthesis of magnetic core-shell structure Fe3O4@MCM-41 nanoparticle by vesicles in aqueous solutions☆

In this study, magnetic core–shel structure Fe3O4@MCM-41 nanoparticles were synthesized with vesicles as soft templates. In the preparation, FeCl2 and tetraethy orthosilicate (TEOS) were selected as Fe processor and Si pre-cursor, respectively. Stable vesicles first formed in 0.03 mol·L?1 1:2 mixture of anionic surfactant sodium dode-cyl sulfate and cationic surfactant cetyltrimethyl ammonium bromide. Then, TEOS was added in the vesicle aqueous solution, leading to a highly dispersed solution. After high-temperature calcination, Fe3O4@MCM-41 nanoparticles were obtained. Their structure and morphology were characterized by Saturn Digisizer, transmis-sion electron microscope and vibrating sample magneto-meter. The results indicate that the vesicles are spherical and their size could be tuned between 20 and 50 nm. The average grain diameter of synthesize magnetic core–shel Fe3O4@MCM-41 particles is 100–150 nm and most of them are in el iptical shape. The dispersion of magnet-ic particles is very good and magnetization values are up to 33.44 emu·g?1, which are superior to that of other Fe3O4 materials reported.     

碳氟表面活性剂在有机液体中的表面活性

从不同的碳氟链（ 包括四氟乙烯五聚体衍生物、全氟丙烯环氧齐聚体衍生物以及全氟烷基衍生物等） 出发, 制备了多种碳氟化合物。通过表面张力测定,研究了碳氟化合物在甲苯、正己烷、正癸烷、环己烷等烃类化合物以及在氯仿、硝基甲烷、二甲亚砜、正丁醇等极性化合物中的表面活性。探讨了表面活性剂结构对其表面活性的影响。     

Spontaneous vesicle formation from trisiloxane-tailed gemini surfactant

The spontaneous vesicle formation from a novel trisiloxane-tailed gemini surfactant were reported. The surface tension measurements revealed that aggregates are formed, and dynamic light scattering (DLS) measurements suggested the aggregates are vesicles. The size and morphology were observed by transmission electron microscopy (TEM). The vesicle formation was further confirmed by dye entrapment studies.     

Aqueous solution properties of a silicone surfactant and its mixed surfactant systems

The aqueous solution properties of a nonionic silicone surfactant of dimethylpolysiloxane and its mixed surfactant systems were studied. It was found that the silicone surfactant has a high surface activity and forms micelles in two steps: premicelles in dilute concentrations and polymolecular micelles above 3.7 × 10⁻⁷ mol dm⁻³. In mixed systems of the silicone surfactant with anionic hydrocarbon or fluorocarbon surfactant, weak intermicellar interactions were found. They are due to electrostatic interaction between hydrophilic groups of the respective micelles. Dye solubilization measurements showed that the solubilized amount of Yellow-OB is greater than predicted by ideal systems. Hydrazo-azo tautomerism is observed in fluorocarbon-silicone surfactant systems, while Yellow-OB is solubilized only in the azo-form in the hydrocarbon-silicone surfactant system.     

新型Gemini磷酸酯两性表面活性剂的合成及应用

以磷酸二氢钠、环氧氯丙烷和十二烷基酰胺基丙基叔胺为原料,合成了一种新型双子磷酸酯两性表面活性剂。对其合成工艺进行了研究．确定了最佳工艺条件．最后对该产品应用性能进行了研究。     

Novel hydrolyzable and biodegradable cationic gemini surfactants: Bis(ester-ammonium) dichloride having a butenylene or a butynylene spacer

Novel cationic gemini surfactants, bis(ester-ammonium) dichlorides having a butenylene or a butynylene spacer and an oxycarbonyl group in the lipophilic part, were prepared conveniently and almost quantitatively by the reaction of the corresponding mono(ester-amine) with a highly reactive allylic- or propargylic dichloride. Most of these surfactants showed excellent surface-active properties and good biodegradability. The effects of the structure of spacer, the position of the oxycarbonyl group in the lipophilic part, the alkylene length between the oxycarbonyl and the ammonio groups, and the acyl chain length of the surfactants on their surface-active properties were examined.     

三种表面活性剂对Fe3O4纳米颗粒的形貌影响

选用十六烷基三甲基溴化铵(CTAB)、聚乙烯吡咯烷酮(PVP)、十二烷基磺酸钠(SDS)3种表面活性剂,研究了这3类不同表面活性剂和不同添加量对Fe3O4纳米颗粒的形貌调控作用,利用透射电镜(TEM)对样品进行表征分析,并给出了机理解释。结果表明:1)3种不同的表面活性剂的加入都获得球形或近球形的纳米颗粒。根据TEM及沉积时间的综合分析,3种活性剂的平均粒径比较:SDS相似文献   

阴离子表面活性剂与阳离子表面活性剂的相互作用(Ⅲ)——高浓度区溶液性质

综述了阴/阳离子表面活性剂混合溶液在浓度比较高时出现的双水相和囊泡现象,并对这种双水相形成条件和囊泡的稳定性进行了比较详细的讨论。阴/阳离子表面活性剂混合溶液中的双水相现象只能在两个非常狭窄的区域形成,可能由不同浓度的胶束溶液、胶束溶液与液晶相或囊泡等组成。在一定的条件下,比较稳定的囊泡可以自发或经过超声处理形成。     

Dissolution of Soap Scum by Surfactants. Part III. Effect of Chelant Type on Equilibrium Solubility and Dissolution Rate of Calcium and Magnesium Soap Scums in Various Surfactant Systems

Soap scum can be effectively removed by using an appropriate surfactant with a chelating agent at a high solution pH. The equilibrium solubilities and dissolution rates of two model soap scums [calcium stearate and magnesium stearate: Ca(C₁₈)₂ and Mg(C₁₈)₂] were investigated in aqueous solutions containing three different types of surfactants [methyl ester sulfonate (MES) as an anionic surfactant; alcohol ethoxylate (EO9) as a nonionic surfactant; and dimethyldodecylamine oxide (DDAO) as an amphoteric surfactant] in the presence of different biodegradable chelants: trisodium ethylenediamine disuccinic acid (Na₃EDDS) and tetrasodium glutamate diacetic acid (Na₄GLDA) compared with disodium ethylenediamine tetraacetate (Na₂EDTA), a chelant with poor biodegradability. The highest equilibrium solubility and dissolution rate of either soap scum were observed at high pH in the DDAO system with Na₄GLDA. In addition, the calcium soap scum had a similar to higher equilibrium solubility and a higher dissolution rate constant as compared with the magnesium soap scum.     

Mixtures of anionic and cationic surfactants with single and twin head groups: Adsorption and precipitation studies

This research reports on the adsorption and precipitation of mixtures of anionic and cationic surfactants having single and twin head groups. The surfactant mixtures investigated were: (i) a single-head anionic surfactant, sodium dodecyl sulfate (SDS), in a mixture with the twin-head cationic surfactant pentamethyl-octadecyl-1,3-propane diammonium dichloride (PODD)—adsorption was studied on negatively charged silica; and (ii) a twin-head anionic surfactant, sodium hexadecyl-diphenyloxide disulfonate (SHDPDS), and the single-head cationic surfactant dodecylpyridinium chloride (DPCI)—adsorption was studied on positively charged alumina. Whereas the mixed surfactant system of SHDPDS/DPCI showed adsorption on alumina that was comparable to the of SHDPDS alone, the mixed surfactant system of SDS/PODD showed increased adsorption on silica as compared with PODD alone. The adsorption of the SDS/PODD mixture increased as the anionic and cationic system approached an equimolar ratio. Precipitation diagrams for mixtures of single- and twin-head surfactant systems showed smaller precipitation areas than for single-head-only surfactant mixtures. Thus, the combination of single- and double-head surfactants helps reduce the precipitation region and can increase the adsorption levels, although the magnitude of the effect is a function of the specific surfactants used.     

颜料黄81改性研究

本文在C I P Y 81 (颜料黄 81 )合成的基础上 ,用不同类型的表面活性剂对其实施表面处理 ,并研究了表面活性剂结构及添加量对C .I.P .Y .81性能的影响。结果表明 ,添加非离子表面活性剂和阴离子表面活性剂 ,例如OP - 7,OS - 1 5及红油 ,可以明显改善C .I.P .Y .81的色光、透明度、流动性及着色力等多项应用性能 ,通过试验得到了较佳的工艺性条件 ,较佳添加量为颜料量的 3%～ 5% (质量分数 )