| It always attracts much interest to investigate new surfactants with high performances. Gemini surfactant is a new class of surfactants. The surfactant is made up of two amphiphilic surfactants-like moieties connected at the level of head group or very close to head group by a spacer of varied nature. In comparison to its corresponding conventional surfactant, Gemini surfactant shows better surface-active property, extremely interesting rheological property, unusual micelle structure and aberrant aggregation behavior, and better synergism with conventional surfactant. Two series of novel cationic Gemini surfactants, a new series of zwitterionic Gemini, a new class of nonionic surfactants with two long-chain alkyls and a new series of double-chain quaternary ammonium salts have been synthesized and characterized through IR, 1H NMR, MS and elementary analysis. Their surface-active properties and foaming properties have been investigated in comparison with their corresponding single-chain surfactants and other cationic Gemini surfactants with similar chemical structures. Solubility of simvastatin in the micelles of the new synthesized nonionic surfactants (polyglycerol diisostearate ethoxylates), solubility of naphthalene, 1-naphthol and 2-naphthol in the micelles of the new synthesized cationic Gemini surfactants {[R-O-CH2-CH(OH)-CH2-N+(CH3)2-(CH2)4-N+(CH3)2-CH2-CH(OH)-CH2-O-R, 2Br-], R: C12H25, C14H29, C16H33} with hydroxyl in hydrophobic chain nearby head group have also been researched. Water-in-gasoline microemulsions stabilized by polyglycerol esters have been examined. The thermal phase behaviors of the new synthesized double-chain quaternary ammonium salts and zwitterionic Geminis have been characterized by differential scanning calorimetry (DSC), a polarized optical microscopy (POM) equipped with a heating stage and X-ray diffraction (XRD).The detail investigations of the paper are as following:1. A series of novel cationic Gemini surfactants with special hydrophobic chains: design, synthesis and performancesIn order to obtain cationic Gemini surfactants with novel chemical structures and excellent properties, a series of novel cationic Gemini surfactants: 3a[C12H25-O-CH2-CH(OH)-CH2-N+(CH3)2-(CH2)4-N+(CH3)2-CH2-CH(OH)-CH2-O-C12H25, 2Br-] , 3b [C14H29-O-CH2-CH(OH)-CH2-N+(CH3)2-(CH2)4-N+(CH3)2-CH2-CH(OH)-CH2-O-C14 H29, 2Br-] and 3c [C16H33-O-CH2-CH(OH)-CH2-N+(CH3)2-(CH2)4-N+(CH3)2-CH2-CH(OH)-CH2-O-C16H33,2Br-] with hydroxyl in hydrophobic chain nearby head group have been designed and synthesized using long chain alcohols (dodecanol, tetradecanol and hexadecanol), epichlorohydrin, dimethylamine and 1,4-dibromo-butane. The chemical structures of the newly designed Gemini surfactants have been characterized by means of IR, 1H NMR, MS and elementary analysis. Surface-active properties involving critical micellar concentration (CMC), equilibrium surface tension of surfactant aqueous solution at concentration of CMC (γcmc) surface excess concentration at surface saturation (Γcmc), area per molecule at the air/water interface at surface saturation (Acmc), negative logarithm of the bulk liquid phase concentration of surfactant required to depress surface tension of solvent by 20mM/m (pC20), a measure of surfactant preference for adsorption relative to micellization (CMC/C20 ratio), and foam properties of these cationic Gemini surfactants have been investigated, in comparison with their corresponding single-chain surfactants and other cationic Gemini surfactants{[C12H25-N+(CH3)2-(CH2)2]2, 2Br-, (C12-4-C12 } with similar structures of the synthesized surfactants. The purpose of this research is to investigate the effect of introducing hydroxyl in hydrophobic chain nearby head group on properties of surfactants, which can reveal the relationship between structure and property of Gemini surfactants.The obtained experimental results indicate that the CMC and γcmc value of the novel cationic Gemini surfactant (3a) are both lower than those of C12-4-C12 . This may be due to the formation of hydrogen bonds between hydroxyls inter molecules or inner molecules, which increases attraction between hydrophobic chains. Thus molecules of Gemini surfactant pack more tightly at the air/water interface. It is concluded that introducing hydroxyl in hydrophobic chain nearby head group can improve surface-active properties of the novel cationic Gemini surfactants.It has been found that the CMC of the synthesized cationic Gemini surfactantsdecreases with the increase of hydrophobic chain length, which indicates that the ability to form micelles in the bulk solution increases with the increase of hydrophobic chain length. Furthermore, the critical micelle concentrations of 3a , 3b and 3c are all one order of magnitude lower than those of their monomeric surfactants. The results suggest that Gemini surfactants exhibit better surface-active properties. However the γCMC value increases with the increase of hydrophobic chain length.The PC20 of the novel cationic Gemini surfactants increases with the increase of hydrophobic chain length. In addition, their PC20 is larger, which indicates Gemini surfactants are more efficient in reducing surface tension of water. The CMC/C20 ratio of 3a is 3.97, which is larger. This indicates that 3a shows greater tendency to adsorb at water/air interface. However, the CMC/C20 ratio of 3b is relative small. This may be due to the formation of multilayers.Foaming ability decreases and foam stability increases with increasing hydrophobic chain length of the novel cationic Gemini surfactants. The 3a and 3b exhibit better foaming ability and foam stability.The solubilization of naphthalene, 1- naphthol and 2- naphthol in the micelles of the novel cationic Gemini surfactants have been examined as a function of surfactant concentration (multiple of CMC). The solubilization power of the micelles for 1 -naphthol and 2- naphthol is much better than that for naphthalene. This result may be due to the different polarities of naphthalene, 1- naphthol and 2- naphthol, which lead to different positions solubilized of them. The solubilization power of the micelles of synthesized cationic surfactants is in order of 3a > 3b > 3c.The result of this research may provide proof for applications of the novel Gemini surfactants in environmental treatment.It can be drawn from the results of the capter that cationic Gemini surfactants with excellent surface-active properties and good foaming properties can be obtained through reasonable design and synthesis.2. A series of novel cationic Gemini surfactants with a special spacer group: design, synthesis and propertiesIn order to obtain cationic Gemini surfactants with novel chemical structures and excellent properties, a series of the novel cationic Gemini surfactants A [C12H25-N+(CH3)2-CH2-CH(OH)-CH2-O-C6H4-O-CH2-CH(OH)-CH2-N+(CH3)2-C12H25,2Cl-, ], B [C14H29-N+(CH3)2-CH2-CH(OH)-CH2-O-C6H4-O-CH2-CH(OH)-CH2-N+(CH3)2-C14H29,2Cl-], and C [C16H33-N+(CH3)2-CH2-CH(OH)-CH2-O-C6H4-O-CH2-CH(OH)-CH2-N+(CH3)2-C16H33, 2C1-] having a spacer group with two flexible and hydrophilic spacer groups (2-hydroxyl-1, 3-propanediyl) in both sides of a rigid and hydrophobic spacer group (1,4-hydroquinonediyl) have been designed and synthesized by reaction of hydroquinone diglycidyl ether with long-chain tert-alkylamine and its hydrochloride. The chemical structures of the novel cationic Gemini surfactants have been characterized by IR, 1H NMR, MS and elementary analysis. A comparative study involving surface-active properties (CMC, γcmc, Γcmc, Acmc, PC20, CMC/C20 ratio), and foaming properties of these cationic Gemini surfactants has been done for the novel cationic Gemini surfactants, their corresponding single-chained surfactants (E) [C12H25-N+(CH3)3, Cl-] and other cationic Gemini surfactants (D) [C12H25-N+(CH3)2-CH2-C6H4-CH2-N+(CH3)2-C12H25, 2Cl-]with similar structures of the newly designed Gemini surfactants. The purpose of this research is to investigate the effect of the structure of spacer group on properties of surfactants, which can reveal the relationship between structure and property of Gemini surfactants.It has been found that the CMC and γcmc value of the novel cationic Gemini surfactant (A) are both lower than those of the other cationic Gemini surfactant (D), which indicates that the introduction of flexible and hydrophilic spacer groups in both sides of a rigid and hydrophobic spacer group can improve surface-active properties of cationic Gemini surfactants. Introducing flexible and hydrophilic spacer groups in both sides of a rigid and hydrophobic spacer group makes the spacer group less rigid, which increases the attraction between hydrophobic chains, and makes molecules of Gemini surfactant pack more tightly at the air/water interface.It has been also found that the CMC values decrease with increasinghydrophobic chain length of the novel cationic Gemini surfactants, which indicates that the ability to form micelles in the bulk solution increases with the increase of hydrophobic chain length. The CMC of the novel cationic Gemini surfactant (A) is one order of magnitude lower than that of the monomeric surfactant (E). The results suggest that Gemini surfactants exhibit better surface-active properties. Furthermore, the logarithm of CMC decreases linearly with increasing the number of carbon atoms in the hydrophobic groups. However the γCMC value increases with the increase of hydrophobic chain length the novel cationic Gemini surfactants.The pC20 of the novel cationic Gemini surfactants increases with the increase of hydrophobic chain length. In addition, their pC20 is larger, which indicates Gemini surfactants are more efficient in reducing surface tension of water. The CMC/C20 ratio of A is relative large. This indicates that A shows greater the tendency to adsorb at water/air interface. However, the CMC/C20 ratio of B is relative small. This may be due to the formation of multilayers.In addition, foaming ability decreases and foam stability increases with increasing the hydrophobic chain lengths of the novel cationic Gemini surfactants. The A and B exhibit better foaming ability and foam stability than E.It can be concluded that cationic Gemini surfactants with excellent surface-active properties and good foaming properties can be achieved through reasonable designs and synthesis.3. Synthesis of polyglycerol esters and their applications in water-in-gasoline microemulsionThe research of microemulsion fuel has been increasingly attracting attentions, which may be due to the coming of energy emergency and great attention of human to environmental pollution. Polyglycerol esters of fatty acids (PGEFs), which are widely used nonionic surfactants, are based on renewable raw materials. The purpose of the research is to widen the range of its application. Four polyglycerol esters of fatty acids including triglycerol diisostearate (TGDIS), pentaglycerol distearate (PGDS), triglycerol monostearate (TGMS) and triglycerol monooleate (TGMO) have been synthesized. The synergistic effects for the mixtures of PGEF (TGDIS, PGDS, TGMS or TGMO) with sodium oleate in solubilizing water in gasoline have been investigated. The effect of a series of alcohols (1-butanol, 2-butanol, 1-propanol and 2-propanol) on the water amounts solubilized in the microemulsion systems of TGDIS/sodium oleate/alcohol/ gasoline/water has been researched. It is shown that the microemulsion system of TGDIS/sodium oleate/1-butanol/gasoline/water exhibited better behavior in solubilizing water than the other systems studied. The best weight ratio of TGDIS/sodium oleate is 6:4, in which the maximum solubilization capacity of water is 2.402 g at 16°C, when the amount of the mixed surfactants and gasoline are 0.740 and 6.000g respectively.In addition, the microemulsion system of TGDIS/sodium oleate/1-butanol/ gasoline/water is more water soluble and less temperature sensitive, in comparison with the microemulsion system of TGDIS/lauryl polyoxyethylene (9) ether (AEO9)/ gasoline/water at the best weight ratio of TGDIS/sodium oleate and TGDIS/ AEO9 (6:4). This may be due to less temperature sensitive of anionic surfactant (sodium oleate) than nonionic surfactant (AEO9). The result of this chapter provides potentially information for applications of polyglycerol esters in microemulsion gasoline. Moreover the results of the research can lead us to understand the relationship between the structure and the emulsifying ability of surfactants throughly. 4. Synthesis of triglycerol diisostearate ethoxylates, their surface properties and the solubilization of drugTriglycerol diisostearate is a hydrophobic nonionic surfactant with two long alkyl chains in its structure, which is a pale yellow liquid at room temperature. A series of triglycerol diisostearate ethoxylates (PGDIS-E36, PGDIS-E40 and PGDIS-E58) have been synthesized by the reaction of triglycerol diisostearate with ethylene oxide. Properties including water solubility, cloud point (CP), CMC, emulsifying ability, foaming properties, relative viscosity, and solubilizing capacity of polyglycerol diisostearate ethoxylates for simvastatin have been investigated in comparison with those of Tween-80. Tween-80 is a nonionic surfactant widely used. There is an unsaturated bond in its structure, which is unstable in properties. So its practical application is limited in some ways. It is important to find a replacement of Tween-80 in some aspects.PGDIS-E36 and PGDIS-E40 are pale yellow liquid at room temperature; while PGDIS-E58 is a pale yellow paste-like solid. Polyglycerol diisostearate ethoxylates show excellent water solubility. The CP of these surfactants is all more than 100 °C. The effect of sodium sulfate on the CP of PGDIS-E36, PGDIS-E40 and Tween-80 is similar, which may be due to their similar HLB values. Furthermore, PGDIS-E58 with longer EO chain length is more sensitive to sodium sulfate, when the concentration of sodium sulfate is above 4.5%.The CMC values of polyglycerol diisostearate ethoxylates are less than 0.01mmol 1-1, which is one order of magnitude lower than that of Tween-80. Furthermore, the emulsifying ability of polyglycerol diisostearate ethoxylates increases with an increase in the number of EO units, and it is also better than that of Tween-80. In addition, foaming properties, relative viscosity of PGDIS-E36, PGDIS-E40 and Tween-80 are similar.Polyglycerol diisostearate ethoxylates are all superior to Tween-80 in enhancing the solubility of simvastatin in their micelles. PGDIS-E40 with appropriate HLB value shows the best effect. The combined use of PGDIS-E40 with ethanol facilitates the solubility of simvastatin. The addition of salt or increasing temperature could result in enhancement of simvastatin solubility in the micelles of PGDIS-E40. The surface properties, emulsifying abilities and solubilization powers for simvastatin of polyglycerol diisostearate ethoxylates are superior to those of Tween-80, which may be due to their different chemical structures. There are two hydrophobic alkyl chains in the molecule of polyglycerol diisostearate ethoxylate. which can increase the attraction of molecules.The results of this chapter indicate that Tween-80 may be replaced by PGDIS-E36, PGDIS-E40 and PGDIS-E58 in some aspects.5. Design, synthesis and characterization of thermal phase behaviors of a series of double-chain quaternary ammonium saltsA series of symmetrical and asymmetrical quaternary ammonium salts with two long alkyl chains {[R1-O-CH2-CH(OH)-CH2-N+(CH3)2-R2, Cl-], R1 R2: C12H25, C14H29, C16H33} have been designed and synthesized by the reaction of the intermediates of long-chain 1-O-alkyl glycidyl ether including 1-O-dodecyl glycidyl ether, 1-O-tetradecyl glycidyl ether and 1-O-hexadecyl glycidyl ether with long-chained tert-alkylamine and its hydrochloride. Their chemical structures have been characterized through IR, 1H NMR, MS and elementary analysis. Their thermal phase behaviors have been confirmed by DSC, POM and XRD.It has been found that the compound with longer alkyl chain length or being more asymmetric exhibits lower melting points (Tm), isotropization temperature (Ti) and narrower mesophase temperature range. The results suggest that the chain length, symmetry and asymmetry affect Tm, Ti and mesophase temperature ranges, but has little influence on the class of thermal phase behaviors. In the temperature of mesophase range, these compounds show oily streaks, netlike, fan-shaped, schlieren texture. XRD results shows that there is a sharp reflex in the small angle region and a diffuse wide peak in the wide angle region. All these confirm that these compounds form cholesteric liquid crystal.6. Design, synthesis and characterization of thermal phase behaviors of a series of zwitterionic GeminisA series of novel zwitterionic Geminis [R-O-CH2-CH(OSO3-)-CH2-N+(CH3)2-R, R: C12H25, C14H29, C16H33] have been designed and synthesized by the reaction of double-chain quaternary ammonium salt with chlorosulfonic acid, then neutralized with sodium hydroxide. Their chemical structures have been characterized through IR. 1H NMR, MS and elementary analysis. The thermal phase behaviors of zwitterionic Geminis have been examined by DSC, POM and XRD, in comparison with double-chain quaternary ammonium salts.It has been found that double-chain quaternary ammonium salts exhibit lower phase transition temperature and narrower mesophase temperature ranges, while zwitterionic Geminis exhibit higher phase transition temperature, wider mesophase temperature ranges, and better thermo-stability. The former forms Ch, while the latter forms Sc. Alkyl chain length, the class of amphiphilic compounds affect Tm, Ti and mesophase temperature ranges. Furthermore, the class of amphiphilic compounds can change the class of thermal phase behaviors, and change thermo-stability greatly. 7. The mail innovations of the paper(1) A series of novel cationic Gemini surfactants {[R-O-CH2-CH(OH)-CH2-N+(CH3)2-(CH2)4-N+(CH3)2-CH2-CH(OH)-CH2-O-R, 2Br-], R: C12H25, C14H29, C16H33} with hydroxyl in hydrophobic chain nearby head group were first designed and synthesized. Their chemical structures have been characterized through IR, 1H NMR, MS and elementary analysis. Surface-active properties, foam properties of these cationic Gemini surfactants have been investigated. The result of this research shows that introducing hydroxyl in hydrophobic chain nearby head group can improve surface-active properties.(2) A series of novel cationic Gemini surfactants {[R-N+(CH3)2-CH2-CH(OH)-CH2-O-C-6H4-O-CH2-CH(OH)-CH2-N+(CH3)2-R, 2C1-], R: C12H25, C14H29, C16H33} having a spacer group with two flexible and hydrophilic spacer groups (2-hydroxyl-l, 3-propanediyl) in both sides of a rigid and hydrophobic spacer group (1, 4-hydroquinonediyl) and were first designed and synthesized. Their chemical structures have been characterized through IR, 1H NMR, MS and elementary analysis. Surface-active properties, foam properties of these cationic Gemini surfactants have been investigated. The results of this research suggest that the introduction of flexible and hydrophilic spacer groups in both sides of a rigid and hydrophobic spacer group can improve surface-active properties of cationic Gemini surfactants.(3) Polyglycerol esters of fatty acids were first investigated in microemulsion gasoline. Polyglycerol esters of fatty acids including triglycerol diisostearate (TGDIS), pentaglycerol distearate (PGDS), triglycerol monostearate (TGMS) and triglycerol monooleate (TGMO) with sodium oleate and co-surfactants including 1-butanol, 2-butanol, 1-propanol and 2-propanol have good symergism in solubilizing water in microemulsion gasoline. In the four polyglycerol esters, TGDIS is the best one. The results of this research show that polyglycerol esters have potential value in microemulsion gasoline. The research paper has been published on Fuel 2007, 86(4), 597-602.(4) A series of triglycerol diisostearate ethoxylates (PGDIS-E36, PGDIS-E40 and PGDIS-E58) were first synthesized using triglycerol diisostearate being hydrophobic nonionic surfactant Surface-active properties, emulsifying ability, foaming properties, relative viscosity, and solubilizing capacity of polyglycerol diisostearate ethoxylates for simvastatin have been investigated in comparison with those of Tween-80. This research provides important information for replacing Tween-80 by PGDIS-E36, PGDIS-E40 and PGDIS-E58 in practical applications. The research paper has been published on J.Disp. Sci. Tech. 2007,28(4), 495-500.(5) A series of double-chain quaternary ammonium salts {[R1-O-CH2-CH(OH)-CH2-N+(CH3)-2-R2, Cl-], R1, R2: C12H25, C14H29, C16H33} were first designed and synthesized. Their chemical structures have been characterized by means of IR, 1H NMR, MS and elementary analysis. Their thermal phase behaviors have been confirmed by DSC, POM and XRD.(6) A series of novel zwitterionic Geminis [R-O-CH2-CH(OSO3-)-CH2-N+ (CH3)2-R, R: C12H25, C14H29, C16H33] were first designed and synthesized. Their chemical structures have been characterized using IR, 1H NMR, MS and elementary analysis. The thermal phase behaviors of double-chain quaternary ammonium salts and zwitterionic Geminis have been confirmed by DSC, POM and XRD in comparison.
|
PDF Full Text Request