Synthesis of ZnS Nanospheres in Microemulsion Containing Cationic Gemini Surfactant

The reverse microemulsion containing cationic gemini surfactant trimethylene‐1,3‐bis(dodecyldimethyl ammonium bromide) (12‐3‐12, 2Br^?) is applied to synthesize ZnS nanospheres. Narrow size distributed ZnS nanospheres with controllable size and uniform morphology are successfully fabricated by direct reaction of ZnCl₂ and Na₂S in the reverse microemulsion systems. Except for the appearance of large aggregates owing to quantum size effects when the incubation time is 2 h, with increasing the incubation time from 12 to 48 h, the diameter of the ZnS nanosphere can be controlled as 20–25 nm and 140 nm, respectively. X‐ray diffraction (XRD), transmission electron microscopy (TEM), and UV‐visible absorption spectroscopy are applied to characterize the resulting ZnS nanoparticles. In the system used in the present study uniform nanosphere morphology can be synthesized, with the incubation time as an important factor in controlling the size of as‐prepared products.     

Salt Effect on the Aggregation Behaviors of an Anionic Carboxylate Gemini and a Cationic Surfactant

The synthesis method and conditions for the carboxylate Gemini surfactant O,O′‐bis(sodium 2‐lauricate)‐p‐benzenediol (C₁₁pPHCNa) were explored. Surface tension data of the single and mixed systems of catanionic (cationic with anionic) surfactants with different salt concentrations were used to determine the CMC values and to obtain the information of self‐assembly behaviors of the surfactants. Aggregates' morphologies were observed by transmission electron microscopy (TEM) and speculation was made according to the viscosity measurement results. The results show that large spherical aggregates formed in the mixed solution, which tend to transfer into branched and wormlike mixed micelles with the increases of the salt concentration. The viscosity of the mixed solution was found to increase gradually corresponding to the change of the catanionic surfactant mixtures' morphology.     

N-烷基咪唑盐酸盐的合成及性能

咪唑及其衍生物常用作药物、抗菌剂、酶抑制剂和其它精细化学品[1 5]。本文通过丙烯腈与咪唑加成生成1 (β 氰乙基)咪唑,然后与溴代烃进行季铵盐消去反应合成N 烷基咪唑,经与HCl中和制得N 烷基咪唑盐酸盐,总收率大于90%。性能研究表明,N 十二烷基咪唑盐酸盐HLB值为12;在硬水中的平均稳定性为5级;润湿力与十六烷基三甲基氯化铵和平平加 O相近;分散力与平平加 O和十二烷基硫酸钠基本相同;发泡力低;对液体石蜡有较好的乳化力。1　实验部分在250ml三口烧瓶中加入13 6g(0 20mol)咪唑、15g甲醇和15g丙烯腈,升温至50～60℃回流反应3h。减压…     

二氯化-N,N-′-二(3-脱氢松香酰氧-2-羟丙基)四甲基乙二胺的合成与性能

研究了Gemini表面活性剂中疏水"尾巴"结构对性质的影响,以脱氢松香酸和环氧氯丙烷为原料合成了中间体3-脱氢松香酰氧-2-羟丙基氯,再与四甲基乙二胺反应,得到1种以脱氢松香酰基为疏水链"尾巴"的对称Gemini型双季铵盐阳离子表面活性剂:二氯化-N,N′-二(3-脱氢松香酰氧-2-羟丙基)四甲基乙二胺。在合成工艺条件的基础上,采用IR光谱、MS谱和元素分析测试技术对产物进行了结构确认。结果表明,该产物可降低水的表面张力达34.9 mN/m,临界胶束浓度为1.0×10-4mol/L。表明具有良好疏水性能的2个大"尾巴"使合成的Gemini表面活性剂更易形成胶束,大大提高了表面活性。     

双子型阴离子表面活性剂的合成及浮选性能

分别以辛酰氯、癸酰氯、十二酰氯为原料,经加成、酰化及皂化等反应合成了3种双子型阴离子表面活性剂。产物结构经IR、1HNMR和13CNMR等波谱测试技术确定。25℃时测定了表面活性参数,结果表明随分子中疏水链增长,临界胶束浓度及表面张力均降低。目标化合物能一定程度增强油酸对胶磷矿中白云石的浮选能力。     

多疏水链阳离子二聚表面活性剂的合成

长链胺与溴代烷通过烷基化反应,生成双长链叔胺,再将其与a,w-二溴代烷进行亲核取代反应,合成出一系列双长链季铵盐型二聚表面活性剂,其结构经1^H NMR和元素分析表征。     

二氯化-N,N-'-二(3-脱氢松香酰氧-2-羟丙基)四甲基乙二胺的合成与性能

研究了Gemini表面活性剂中疏水"尾巴"结构对性质的影响,以脱氢松香酸和环氧氯丙烷为原料合成了中间体3-脱氢松香酰氧-2-羟丙基氯,再与四甲基乙二胺反应,得到1种以脱氢松香酰基为疏水链"尾巴"的对称Gemini型双季铵盐阳离子表面活性剂二氯化-N,N'-二(3-脱氢松香酰氧-2-羟丙基)四甲基乙二胺.在合成工艺条件的基础上,采用IR光谱、MS谱和元素分析测试技术对产物进行了结构确认.结果表明,该产物可降低水的表面张力达34.9 mN/m,临界胶束浓度为1.0×10-4 mol/L.表明具有良好疏水性能的2个大"尾巴"使合成的Gemini表面活性剂更易形成胶束,大大提高了表面活性.     

Rheological property and rheokinetics of novel photogelling fluids

A novel photorheological fluid composed of cationic Gemini surfactant N, N’-bis (octadecyl dimethyl)-1, 2-dichloride-propyl ammonium salt (C₁₈-3-C₁₈) and trans-ortho-methoxycinnamic acid (trans-OMCA) was investigated. When C₁₈-3-C₁₈ and trans-OMCA are mixed in equimolar quantities, the result is a low-viscosity Newtonian fluid with no thixotropy. After irradiation by UV light (365?nm), trans-OMCA is converted to cis-OMCA, and in turn, the solution undergoes more than 50 fold increase in the relative viscosity and exhibits shear thinning and thixotropy. The viscosity rise is associated with the formation of wormlike micellar network in the solution, which was confirmed by cryo-scanning electron microscopy (cryo-SEM). Furthermore, the rheokinetics process of the C₁₈-3-C₁₈/trans-OMCA solutions during UV irradiation was studied and rheokinetics equation was established, which can well describe the dynamic changing of the rheological properties. Critical packing parameter was introduced to explain the mechanism of photo-induced micelle transition.     

Rheological Properties of Mixed Aqueous Solutions of Geminis (12‐3‐12,2Br−) and SDS

The rheological properties of surfactant solutions are the main parameter that affects the surfactant application. In this work, the rheology of the mixed system 12‐3‐12,2Br^?/SDS/H₂O was discussed particularly. The relationship between the microstructure of surfactant aggregates and rheology of mixed solutions was explored. It is shown that the rheological properties of solutions have different behaviors at different molar ratio of two surfactants under given total concentration. With the increase of molar ratio (12‐3‐12,2Br^?/SDS), the solution change from Newtonian liquid into positive thixotropy then to negative thixotropy, at last turn to positive thixotropy again, and ATPS becomes the dividing line. The difference of rheological properties is the embodiment of difference for surfactant aggregates' microstructures. The cryo‐TEM results shown that the solutions containing aggregates with big size, such as rodlike micelles, multilamellar micelles, show positive thixotropy. However, the solutions containing lamellar micelles or liquid crystal will show negative thixotropy. The positive thixotropy endows the mixied system a potential application in enhanced oil recovery.     

溴化-1-(α-辛基吡啶)-6-(α-十二烷基吡啶)己烷的合成与表征

双子表面活性剂是通过联结基将两个相同头基和相同疏水链的普通表面活性剂在头基或靠近头基处以化学键方式连接在一起,这种表面活性剂与相应的普通表面活性剂相比,具有更高的表面活性[1],已引起学术界和工业界人士的广泛兴趣和关注。分子结构不对称的双子表面活性剂,包括不同化     

Study on the Interfacial Tensions Between Oils and Alkylbenzene Sulfonate Gemini Surfactant Solutions

Interfacial tensions (IFT) of five alkylbenzene sulfonate Gemini surfactants Ia, Ib, Ic, Id, and Ie at different oils/water systems were measured by a spinning drop interfacial tensiometer. And critical micelle concentration (CMC), the interfacial tension at CMC (γ_CMC), maximum interfacial excess concentration (Γ _max) and the surface area per molecule (A_min) were calculated. The results indicated that the CMC values determined with interfacial tension method were lower than those determined with surface tension method. And γ_CMC for Ie is larger than that for Ia, Ib, Ic, and Id. In addition, the effects of temperature and hydrophobic chains on dynamic IFT were also studied. With the increment of temperature, dynamic IFT is easier to reach a stable value. However, with the increment of hydrophobic chains, dynamic IFT is more difficult to reach a stable value. Each Gemini surfactant produces a minimum IFT when measured against a different n-alkane.     

Removal of Congo red dye by gemini surfactant C12-4-C12 · 2Br-modified chitosan hydrogel beads

In this paper, chitosan hydrogel beads were modified with gemini surfactant C₁₂-4-C₁₂ · 2Br and then used for the adsorption and removal of Congo red dye. The effects of pH, inorganic salt, temperature, shaking rate, and surfactant concentration were investigated in detail. The gemini surfactant concentration was the main factor, and the maximum adsorption amount was observed at 0.5% C₁₂-4-C₁₂ · 2Br. The Sips isotherm model fit well with the equilibrium experimental data, and the values of the heterogeneity factor (n) indicated heterogeneous adsorption. The adsorption kinetics was found to follow the pseudo-second-order rate model better than the pseudo-first-order rate model.     

Aggregation behaviors of amine-oxide gemini surfactants

The micellar aggregation of a series of gemini surfactants [N, N’-dimethyl-N, N’-bis(2-alkylamideethyl)-ethylenediamine oxide (alkyl?=?C₁₁H₂₃, C₁₃H₂₇, C₁₅H₃₁)] in aqueous media has been investigated. The results show that there is an excellent agreement among the critical micelle concentration (CMC) values obtained by surface tension and steady-state fluorescence methods. Because of the occurrence of self-coiling or the formation of pre-micellization, the CMC values, the I₁/I₃ values, and the micelle aggregation numbers (N_agg) at CMC (N_m) increase with the hydrophobic alkyl chain length increasing. Besides, vesicles are observed above the CMC for all these surfactants.     

Effects of Spacer Chain Length and Additives on Solution Properties of Cationic Gemini Surfactant

The critical micelle concentration (CMC) has been determined for the gemini surfactant trimethylene-1,3-bis(dodecyldimethyl ammonium bromide)12-s-12,2Br^?1 by means of electricity conductivity measurements. For the same number of carbon atoms in the hydrophobic chain per hydrophilic head group, geminis have CMC values well below those of conventional single-chain cationic surfactants. The CMC of 12-3-12 reduces with the addition of n-alcohol except ethanol and with the increase of n-alcohol chain length as well as increase of concentration of n-butanol and sodium chloride. Steady-state fluorescence quenching technology has been employed to study the aggregation number of micelle, which increases with increase in the length of n-alcohol. The Kraft temperature measurements also indicate that the stability of solid surfactant hydrate decreases along with the improvement of concentration of n-butanol and sodium chloride.     

基于烷基酰胺双羧酸盐表面活性剂的合成及其性质

以四氢苯酐为起始原料,依次经酯化、酰胺化及氧化开环反应合成了新型烷基酰胺双羧酸盐双子表面活性剂(4),其结构经¹H NMR, IR和MS(ESI)表征。通过浊点法测得其Krafft点低于0 ℃;通过电导率法测得其CMC为3.729×10^-3 mol·L^-1;利用滴体积法测得CMC为3.402×10^-4 mol·L^-1, γ-CMC为36.88 mN·m-¹。 4的起泡性能、乳化性能良好,优于SDS。