Lvbo Cheng

Synthesis and characterization of a series of carbamate-linked cationic lipids for gene delivery

A series of pH-sensitive lipids, 1a-h [(2,3-bis-alkyl-carbamoyloxy-propyl)-trialkylammonium halide] and 2a-d (1-dimethylamino-2,3-bis-alkylcarbamoyloxy-propane), with carbamate linkages between the hydrocarbon chains and an ammonium or tertiary amine head, were synthesized for liposome-mediated gene delivery. The variable length of the carbon chains and the quaternary ammonium or neutral tertiary amine heads allowed us to identify the structure-function relationship showing how these factors would affect cationic lipid in gene delivery performance.

Structure–Function Relationship Research of Glycerol Backbone-Based Cationic Lipids for Gene Delivery

Transfection activities of two series of synthetic glycerol backbone‐based cationic lipids were studied as gene delivery carriers. The variable length of hydrocarbon chains, diverse quaternary ammonium heads, different linkage, as well as alternative anion combined with them allowed to find how these factors affect cationic lipids on their gene delivery performance. The structure–function relationship of the synthetic glycerol backbone‐based cationic lipids was discussed, and the transfection efficiency of some of the cationic liposomes was superior or parallel to that of two commercial transfection agents.

Synthetic Diether‐linked Cationic Lipids for Gene Delivery

Quaternary ammonium lipids 2a–p, with diether linkages between hydrocarbon chains and their ammonium headgroups, were synthesized as potential vectors for cationic liposome‐mediated gene delivery. Varying the length of carbon chains and quaternary ammonium heads as well as different anionic complexes will enable the study of the structure–function relationships of these cationic lipids in terms of gene delivery properties.

Dynamic Interfacial Tension between Crude Oil and Dodecylmethylnaphthalene Sulfonate Surfactant Flooding Systems

Abstract The surface tension of surfactant aqueous solutions and dynamic interfacial tensions (DIT) between crude oil, offered from Shengli Oil Field in China, and surfactant flooding systems, and the single-component dodecylmethylnaphthalene sulfonate (DMNS) surfactant, developed in our laboratory, were measured. In the present report, both buffered alkali and no alkali flooding systems were investigated. It was found that DMNS surfactant possessed great capability and efficiency of lowering the solution surface tension and the critical micelle concentration (cmc) is 0.002 mass% and the surface tension at this concentration is 29.39 mN.m−1. It was also found that the DMNS surfactant is also greatly effective in reducing the interfacial tensions and can lower the tension of crude oil-water interface to ultra-low at very low surfactant concentration and an optimum range of sodium chloride. The lower alkali concentration is favorable for lowering DIT. The higher alkali concentration needs a higher surfactant concentration for oil flooding systems lowering DIT. Moreover, the results indicate that there obviously exists both synergism and antagonism among the surfactant, alkali and inorganic salt. The added surfactant play an important role in reducing DIT, and the prepared DMNS surfactant possesses great capability and efficiency in lowering the interfacial tension between oil and water. The salt-modified surfactant flooding systems without alkali, decreasing the cost of oil recovery and avoiding the stratum being destroyed would have a great prospect for enhanced oil recovery.

Liquid Phase Benzoylation of Naphthalene over Hβ Zeolite for Synthesizing 2-Benzoylnaphthalene

Abstract It is economical to develop green synthetic process by using the by-product of Heavy-oil Contact Cracking Process (HCC) to form 2-benzoylnaphthalene. Benzoylation of naphthalene with benzoyl chloride was carried out over five kinds of zeolites. And Hβ zeolite represented very high catalytic activity and good selectivity for 2-benzoylnaphthalene. The benzoylation over Hβ zeolite for producing 2-benzoylnaphthalene was studied in detail by a series of experiments on relative influencing factors. Catalyzed by a four-times exchanged β zeolite (10 g/mol benzoyl chloride) which was calcined at 550°C, the benzoylation (100% conversion of benzoyl chloride and 87.7% selectivity for 2-benzoylnaphthalene) had been carried out at 220°C for 5 hr with 2 molar ratio of naphthalene to benzoyl chloride.

Structural Effect on Surface Properties of Alkylbenzenesulfonates Having Branched Chains

Abstract The relationship of surface properties and hydrophobic branched-chain structure was studied using nine pure alkylbenzenesulfonates of three series synthesized in our laboratory. The effects of the position of the benzene ring and the sulfonic group on surface activities were studied. From the surface tension measurements, we found that when the position of benzene ring shifts to the middle of the alkyl chain, Γmax decreased while γcmc decreased, at the same time, cmc decreased and A m increased.

Synthesis and Surface Activity of Novel Anionic Arylalkyl Surfactants: Sodium N-aryloleyl p-methoxyanilinesulfonics

Abstract Anionic arylalkyl surfactants: sodium N-aryloleyl p-methoxyanilinesulfonics (SAM) were synthesized. One of them was characterized by IR and 1HNMR. The values of critical micelle concentration (CMC) and the surface tension (γcmc) at the CMC were determined.

Synthesis and Characterization of Mono-Isomeric Alkylbenzene Sulfonates

Abstract The synthesis of a series of isomer pure mid-position alkylbenzene sulfonates is described. Three isomers—4-(1-ethyldodecyl)benzene sodium sulfonate, 4-(1-butyldecyl)benzene sodium sulfonate, and 4-(1-hexyloctyl)benzene sodium sulfonate—were synthesized. High performance liquid chromatography (HPLC) indicated that the isomers were of 99.9%, 96.2%, and 97.5% purity, respectively. Their structures were characterized to be correct by electrospray ionization-mass spectrometry (ESI-MS), 1H NMR, and 13C NMR investigations. Furthermore, the purity and structure of the three kinds of intermediates were also determined by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS).

Theory analysis of mass spectra of long-chain isocyanates†

Electron impact mass spectra of four long-chain isocyanates, lauryl isocyanate, tetradecyl isocyanate, hexadecyl isocyanate and octadecyl isocyanate, were obtained with a GCT high-resolution time-of-flight mass spectrometer. The four isocyanates studied gave a common base peak of m/z 99, which suggested the formation of a stable six-membered ring structure to decentralize the positive charge. Quantum-mechanical energy calculation justified that the six-membered ring base peak had the lowest energy. The positive charge assigned during the fragmentation of the radical cation, and the relative intensity of the fragment ion peaks, were explained by quantum-mechanical calculations as well.

Physicochemical Properties of Aryl Oleate Surfactants in Aqueous Solution

Abstract Sodium and potassium aryl oleates, containing different aromatic rings on the straight aliphatic chain, were synthesized. Their surface properties at 25°C, surface tensions at CMC, γcmc, surface excess concentration, Γ m , the area per surfactant molecule at the air/water interface at surface saturation, A m , efficiency in surface tension reduction, pC20, effectiveness in surface tension reduction, ∏cmc, as well as standard free energies of adsorption, Δ G ads°, and of micellization, Δ G mic°, were determined. The CMCs and γcmcs of these surfactants increased with the increase of the size of aromatic ring from phenyl to a-methylnaphthyl. Introduction of aromatic rings to the alkyl chain decreased the efficiency and effectiveness in reducing water surface tension. The results indicated that the size of lipophilic group was important in effecting the interfacial surface area occupied by the surfactant molecules.