Synthesis of lipopolyhydroxylalkyleneamines for gene delivery
Various bis(2-hydroxy-3-chloropropyl)alkylamines were synthesized by coupling primary amine with epichlorohydrin and utilized as a monomer to react with ethylenediamine (EDA), N,N′-dimethylethylenediamine (DMEDA), or tetramethylethylenediamine (TMEDA) to generate a series of lipopolyhydroxylalkyleneamines. The number- and weight-average molecular weight (Mn and Mw) and polydispersity index (Mw/M n) of the lipopolyhydroxylalkyleneamines were dependent on reactant solvent and reaction temperature. The compounds with EDA as backbone have better transfection activity and lower toxicity than those with DMEDA and TMEDA as backbone.
A novel gemini viscoelastic surfactant (VES) for fracturing fluids with good temperature stability
A category of gemini surfactants with novel structures were designed and synthesized as thickening agents of clean fracturing fluids in this research. The desired products were characterized by high resolution mass spectrometry (ESI-HRMS) and infrared spectrometry (FT-IR GX). Fluid samples with a formula of 5 wt% of products and 1 wt% of KCl were evaluated. The SEM studies revealed a good network microstructure and obvious viscoelasticity, which is favorable for a proppant suspension. Furthermore, the evaluation of their rheological properties at high temperatures revealed good thermal stabilities of these fluids up to 139 °C, particularly for VES-M (the spacer for the surfactant using methylamine and epoxy chloropropane). Comparative analysis of the rheological properties showed that since long chains of N-substituents in the middle of the molecules could enhance steric hindrance and rigidity, it is unfavorable for molecular entanglement and increases the viscosity of the VES aqueous solution. Proppant-support and gel breaking evaluations were also performed. It can be seen that nearly 100% proppant suspension was observed for 180 min at ambient temperature and complete gel breaking was achieved.
Structure and Reactivity of Oxirane Chemical Modifiers for Gelatin
New chemical modifiers for gelatin, glycidylamines, are synthesized.Acid-base properties of glycidylamines and the kinetics of reactions of oxirane compounds with nucleophilic reagents, among them aqueous solution of gelatin, are studied.
Chezlov, I. G.,Zavlin, P. M.,Kuznetsov, L. L.
p. 155 - 161
(2007/10/03)
DIGLYCIDYLALKYLAMINES AND THEIR HARDENING ACTION.
The authors study the synthesis and hardening action of a number of diglycidylalkylamines. The synthesized compounds were tested as hardeners of photosensitive gelatin emulsions. They were introduced in the form of aqueous-alcoholic solutions in amounts of 2. 7 multiplied by (times) 10** minus **3-1. 1 multiplied by (times) 10** minus **2 M into the prepared positive emulsion containing all the coating additives. Examination of the results shows that all the compounds studied are effective hardeners. They raise the melting point of the emulsion coating to 74-100 degree after only 24 h of thermostatic aging. The strength of the hardened coatings reaches 200-400 g. The commercial hardener Du-652 is less effective.
Zavlin,Chezlov,Levit,Shuravina,Mikhailova
p. 1317 - 1318
(2007/10/02)
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