阴离子孪连表面活性剂的合成及其表/界面活性研究

合成了疏水链长度不同和连接基长度不同的7种系列阴离子孪连表面活性剂,研究了它们的表/界面活性。结果表明,它们有较低的表面张力和临界胶束浓度(CMC),有很好的表面活性。它们的CMC都在10-5~10-6mol/L之间,表面张力在26·5~34mN/m之间。它们有非常好的抗一价、二价盐的能力。除了C16-C2-C16在高于5%的NaCl溶液中会产生析出外,其余孪连表面活性剂都能耐盐20%以上。随着盐浓度的增加,孪连表面活性剂与烷烃间的界面张力逐渐降低,能达到10-3mN/m。与中原油田原油间的界面张力能降低到10-3~10-4mN/m,表明它们可应用于特高矿化度油藏提高采收率。     

三联阳离子表面活性剂的合成及复配性能

以环氧氯丙烷、叔胺、甘油为主要原料,水为溶剂,经过开环、季铵化反应,合成了新型三联季铵盐阳离子表面活性剂(Ⅲ-12-4),得率为86.9%。采用质谱和元素分析测试技术对产物结构进行表征,证明所得产物即为目标产物。通过采用DCA-315型表面张力及动态接触角分析仪对表面张力的测定研究了其与十二烷基硫酸钠(SDS)复配体系的表面化学性质,稳态荧光探针法考察了微极性变化,还得到了胶束聚集数。结果表明,复配体系与单一体系相比,具有更低的临界胶束浓度(cmc)和降低表面张力的效能,表现出协同效应。当n(Ⅲ-12-4)∶n(SDS)=3∶7时,复配体系的临界表面张力(γcmc)和临界胶束浓度分别为16.95mN/m和1.33×10-5mol/L,并且胶束聚集数只有SDS的1/6,混合胶束结构紧密,微极性降低。     

单一及复合表面活性剂对联苯菊酯微乳液的影响

通过对单一及复合型表面活性剂水溶液临界胶束浓度(CMC)和表面张力(γcmc)的测定分析,研究了表面活性剂对以水为介质、环己酮为溶剂形成的联苯菊酯质量分数为2.5%微乳液相行为及稳定性的影响.结果表明,在几种单一非离子表面活性剂中,苯乙烯基苯酚聚氧乙烯聚氧丙烯醚嵌段型非离子表面活性剂EPE的γcmc最低,为28.18 mN/m;按m(EPE):m(SDBS)=2∶1形成的复合型表面活性剂水溶液的γcmc更低,为27.60 mN/m,有利于O/W型微乳液的形成,当其质量分数为10%时,配制联苯菊酯质量分数为2.5%微乳液的有效成分热贮分解率为2.35%.     

表面活性剂的协同作用在甲维盐微乳剂中的应用

通过测定不同类型的单一及复配型表面活性剂水溶液的临界胶束浓度和表面张力,研究了它对W(甲维盐)=1%微乳剂的性能影响。膦酸酯类阴离子表面活性剂A的临界胶束浓度为1.79×10-4mol/L,表面张力为28.90mN/m;苯乙烯基酚聚氧乙烯聚氧丙烯醚嵌段型非离子表面活性剂B(EPE型)的临界胶束浓度为1.91×10-4mol/L,表面张力为20.70mN/m;按m(A)∶m(B)=2∶3形成的复配型表面活性剂2#的水溶液的临界胶束浓度为9.30×10-5mol/L,表面张力为25.66mN/m。当W(2#)=10%时,配制W(甲维盐)=1%的微乳剂物理稳定性最佳,各项指标均合格。对甘蓝小菜蛾幼虫的田间药效的试验,结果表明该药剂具有较强的杀虫作用和较长的持效期,具有较好的推广应用前景。     

Gemini表面活性剂烷烃尾链在吸附和聚集过程中的疏水协同效应(英文)

以表面张力法测定了系列Gemini表面活性剂m-6-m以及对应单体表面活性剂CmTABr的临界胶束浓度(cmc)和降低水表面张力20mN·m-1需要的浓度(pC20).比较这些参数表明m-6-m胶束化和在界面吸附的能力均强于CmTABr,这被归结为Gemini表面活性剂烷烃尾链间的疏水协同效应.与不对称Gemini表面活性剂12-6-m比较,对称的Gemini结构更有利于表面活性剂的聚集和吸附.     

基于丙二酰胺的不对称双子表面活性剂的合成及其乳化性能

将二(3-二甲氨基丙基)丙二酰胺分别与溴代十六烷和溴代十四烷反应,生成的季铵盐化产物经丙酮-乙腈重结晶,得到含丙二酰胺基的不对称阳离子双子(Gemini)表面活性剂(命名为16-9-14),总收率为45.9%(以溴代十六烷计);利用红外光谱和核磁共振谱表征了合成产物的结构,采用电导法测定了其临界胶束浓度(CMC),采用滴体积法测定了其临界张力(γCMC),进而初步探讨了其发泡沫性能和乳化性能.结果表明,合成的Gemini表面活性剂的CMC为1.57×10-4 mol/L,γCMC为38.45mN/m;其发泡性能和乳化性能优于相应的单子表面活性剂.     

支链化阳离子和甜菜碱表面活性剂对聚四氟乙烯表面润湿性的影响

利用座滴法研究了支链化阳离子表面活性剂十六烷基羟丙基氯化铵(C₁₆GPC)和两性离子表面活性剂十六烷基羧酸甜菜碱(C₁₆GPB)在聚四氟乙烯(PTFE)表面上的吸附机制和润湿性质, 考察了表面活性剂浓度对表面张力、接触角、粘附张力、固液界面张力和粘附功的影响趋势. 研究发现, 低浓度条件下, 表面活性剂疏水支链的多个亚甲基基团与PTFE表面发生相互作用, 分子以平躺的方式吸附到固体界面; 支链化表面活性剂形成胶束的阻碍较大, 浓度大于临界胶束浓度(cmc)时, C₁₆GPC和C₁₆GPB分子在固液界面上继续吸附, 与PTFE作用的亚甲基基团减少, 分子逐渐直立, 固液界面自由能(γ_sl)明显降低. 对于支链化的阳离子和甜菜碱分子, 接触角均在浓度高于cmc后大幅度降低.     

新型脲基双子表面活性剂的合成及其性能

以N,N-二甲基-1,3-丙二胺、固体光气、溴代烷为原料合成了三种新型含脲基双子表面活性剂(LY-12、LY-14、LY-16),并通过1H NMR、ESI-MS和FT-IR表征了结构。测定了其Krafft点、乳化性能、起泡性能;通过测定表面张力γcmc以及不同温度下的临界胶束浓度(CMC)计算表面活性参数(Γmax、Amin、pc20)与热力学参数(ΔGmθ、ΔHmθ、ΔSmθ)。结果表明,LY-12、LY-14的Krafft点低于0℃,LY-16的Krafft点低于10℃;LY-12、LY-14、LY-16的乳化时间分别为173、275和338 s;LY-12的起泡性显著优于LY-14和LY-16;三种表面活性剂的表面张力γcmc分别为38. 77、37. 42和36. 59 m N/m;298. 15K条件下,其CMC值分别为0. 19、0. 15、0. 13 mmol/L。表面活性参数与热力学参数计算表明,三种表面活性剂均具有高的表面活性且胶束的形成是熵驱动的自发放热过程。     

CMC系列高分子表面活性剂与原油超低界面张力形成机理的研究

采用动态激光光散射及环境扫描电镜研究了羧甲基纤维素系列高分子表面活性剂与大庆原油形成超低界面张力的机理.结果表明,CMC系列高分子表面活性剂具有与低分子量表面活性剂相比拟的表/界面活性,其水溶液的表面张力可达2835mN/m,界面张力达到10^-110mN/m.碱的加入可显著降低高分子表面活性剂与原油的界面张力,在适当条件下界面张力达到超低值(10^-3mN/m),可望作为三次采油的驱油剂.等效烷烃模型研究表明,用碱与原油酸性组分的作用来解释碱能使界面张力下降至超低值的传统观点是不完善的,加入碱能使高分子表面活性剂胶束解缔,胶束数量增多,胶束粒径减小,单分子自由链增加,有利于高分子表面活性剂向界面迁移和排布,这是高分子表面活性剂和碱复配体系与原油界面张力下降至超低值的主要原因.     

双酯基型Gemini表面活性剂的合成及其性能

以1,4-环己二醇、氯乙酰氯、长链叔胺(RN(CH_3)_2,R=10、12、14、16)为原料,合成了一系列不同长度烷基链的双酯基型Gemini表面活性剂(分别命名为C10-EG-10、C12-EG-C12、C14-EG-C14、C16-EG-C16),用FTIR、NMR(~1H、~(13)C)对中间体及产物进行了表征,并研究了表面活性剂的表面性能及抑菌能力。结果表明:在298.15K时,采用铂金环法测定了合成的4种不同长度烷基链Gemini表面活性剂的临界胶束浓度,C10-EG-C10、C12-EG-C12、C14-EG-C14、C16-EG-C16的CMC值分别为5.495、1.096、0.186、0.045 mmol·L~(-1),与传统单链季铵盐表面活性剂相比,合成的Gemini表面活性剂具有较低的CMC值。胶束化热力学参数结果表明在形成胶束过程中是自发放热的。对合成的4种表面活性剂进行了乳化性能、起泡性能和抑菌测试,C14-EG-C14表面活性剂具有很好的乳化能力;C16-EG-C16 Gemini表面活性剂具有良好的稳泡能力;C10-EG-C10表面活性剂具有良好的抑菌能力。     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.     

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd₂(dba)₃-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles by intramolecular nitrilimine cycloaddition

Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles.