Stoichiometry and Stability Constant Values for Copper (II) Chelates with Ethylene Diamine in Deep Eutectic Solvents (DES) (Ethaline) Solutions

In this study we used the deep eutectic solvents (ionic liquids) to investigate the reaction between copper (II) with ethylene diamine (en). Two of the existing methods for analyzing spectrophotometric measurements have been applied for establishing, the stoichiometry and whenever possible, the stability constants of the chelates formed. The method of continuous variations was necessary to determine first whether, the metal ion and the ligand ethylene diamine form one or more than one chelate, when more than one chelate formed, the results obtained depend on the wavelength and for meaningful conclusions the wavelengths were carefully selected. The empirical formulae of the chelates were further substantiated by the molar ratio method. The effect of time and temperature on the formation and stability of these chelates in solution is also studied. The stability constants, K1 and K2 for the copper (II) chelates were calculated, though reliable, and are comparable to literature values.

Theory and Practice of Ionic Soil Stabilizer Reinforcing Special Clay

The change in the thickness of water films of special clay particles such as sliding clay, red clay, and expansive clay is an important factor in producing geological disasters and geological environmental damage. In order to reduce the thickness of water films, ionic soil stabilizer （ISS） is used to treat sliding clay, red clay, and expansive clay. Direct shear test of sliding clay and shrinkage, free swell rate, zeta potential, and cation-exchange capacity of red clay and expansive clay are carried out. The results show that as the plastic indexes of special clay soil decrease, the shear strength of sliding clay increases, the shrinkage and free swell rate of red clay and expansive clay decrease, and the thickness of the water film thins after treatment with the ionic soil stabilizer. Therefore, the geological engineering disasters caused by changes in the thickness of water films of special clay can be effectively inhibited.

Multiple-SO3H functioned ionic liquid as efficient curing agent for phthalonitrile-terminated poly(phthalazinone ether nitrile)

Combined with the advantages of low melting point,high thermal stability and strong acidity,a multipleSO_3H functioned ionic liquid（MIL） was developed successfully as a curing agent to promote the curing reaction of phthalonitrile-terminated poly（phthalazinone ether nitrile）（PPEN-Ph）.The curing kinetics over differential scanning calorimetry（DSC） showed that both the initial curing temperature Tp0＇ and apparent activation energy Ea＇（based on Kissinger equation） were reduced significantly over MIL（207.9℃ and 101.5 kJ/mol） compared to the common curing agent ZnCl_2（268.5℃ and 201.5 kJ/mol）.Moreover,under identical curing conditions,the resulting thermosetting resin over former（Td5%=526.1℃） showed better thermal stability than that over latter（Td5%=512.1 ℃）.These results indicated that MIL should be a good candidate as a curing agent for phthalonitrile resins.