Zuliang Liu

Theoretical study on a novel high-energy density material 4,6,10,12-tetranitro-5,11-bis(nitroimino)-2,8-dioxa-4,6,10,12-tetraaza-tricyclo[7,3,0,03,7]dodecane

A novel high-energy density material (HEDM) 4,6,10,12-tetranitro-5,11-bis(nitroimino)-2,8-dioxa-4,6,10,12-tetraaza-tricyclo[7,3,0,03,7]dodecane was designed and studied by a density functional theory (DFT) method. The geometric structure and thermodynamic properties were investigated at the B3LYP/6-31G (d,p) level. The heat of formation (HOF) and detonation properties were predicted by isodesmic reactions and Kamlet–Jacobs equations. The bond dissociation energy (BDE) and impact sensitivity were also studied to give a better understanding of its chemical and physical properties. The calculated results indicate that 4,6,10,12-tetranitro-5,11-bis(nitroimino)-2,8-dioxa-4,6,10,12-tetraaza-tricyclo[7,3,0,03,7]dodecane belongs to the P space group, with cell parameters Z = 2, a = 13.554 A, b = 8.552 A, c = 15.575 A, α = 70.638°, β = 29.515° and γ = 82.702°. In view of the heat of formation (HOF, 530.36 kJ mol−1), detonation velocity (D, 9.72 km s−1), detonation pressure (P, 45.12 GPa), bond dissociation energy (BDE, 109.85 kJ mol−1) and impact sensitivity (h50, 20.79 cm), it is predicted that 4,6,10,12-dinitro-5,11-bis(nitroimino)-2,8-dioxa-4,6,10,12-tetraaza-tricyclo[7,3,0,03,7] dodecane could be considered as a potential candidate high-energy density compound.

Investigations on the demetalation of metalloporphyrins under ultrasound irradiation.

An efficiently facile method for the demetalation from metalloporphyrins has been developed, which uses high-intensity ultrasound to initiate the ligand dissociation in a mixed solvent of (CH(3)CO)(2)O/HCl with FeSO(4). The influences of substituents, bath temperature and reaction time on the reactions were also investigated, on the base of which the mechanism of demetalation and the effect of ultrasound irradiation on metal-ligand cleavage have been discussed in detail.

Thermal decomposition mechanism of Co–ANPyO/CNTs nanocomposites and their application to the thermal decomposition of ammonium perchlorate

A chemical precipitation method was used to prepare cobalt complexes of 2,6-diamino-3,5-dinitropyridine-1-oxide/carbon nanotube (Co–ANPyO/CNTs) nanocomposites. The structure and thermal analyses indicate that Co–ANPyO nanoparticles are well dispersed on the surface of CNTs with an average particle size of about 10 nm, the content of Co–ANPyO nanoparticles in nanocomposites is about 73.4 wt%. The thermal decomposition mechanism of Co–ANPyO and Co–ANPyO/CNTs nanocomposites were predicted based on thermogravimetry-differential scanning calorimetry (TG-DSC) and thermolysis in situ rapid-scan FTIR (RSFTIR) results. The thermal decomposition of Co–ANPyO and Co–ANPyO/CNTs nanocomposites contains two exothermic processes in the temperature range of 25–490 °C. The first exothermic process for Co–ANPyO/CNTs nanocomposites shifts towards lower temperatures compared to that of Co–ANPyO. The main products of the final residues for Co–ANPyO and Co–ANPyO/CNTs nanocomposites at 490 °C are Co3O4 and CoO, respectively. The catalytic performance of Co–ANPyO and Co–ANPyO/CNTs nanocomposites on thermal decomposition of ammonium perchlorate (AP) was investigated by TG-derivative thermogravimetry (DTG), DSC, non-isothermal kinetic and α–T kinetic curves analyses. The possible catalytic mechanism was also discussed and proposed. During the thermal decomposition process of AP with Co–ANPyO/CNTs nanocomposites, Co–ANPyO/CNTs nanocomposites might decompose and form Co3O4/CNTs and CoO/CNTs nanocomposites as high activity catalysts, which could accelerate the thermal decomposition of AP. Thus, Co–ANPyO/CNTs nanocomposites not only lower the decomposition temperature and activation energy, but also enhance the total heat of AP, which could not be achieved by the CNTs and Co–ANPyO alone. The way of preparing Co–ANPyO/CNTs nanocomposites presented in this work can be expanded to other energetic additives/CNTs nanocomposites used for AP and AP based propellants.

Synthesis of a novel piperidine-functionalized poly(ethylene glycol) bridged dicationic ionic liquid and its application in one-pot synthesis of substituted 2-amino-2-chromenes and 3,4-dihydropyrano[3,2-c]chromenes in aqueous media

A novel piperidine-functionalized poly(ethylene glycol) bridged dicationic ionic liquid was prepared and identified. It was used as a recyclable catalyst for the synthesis of substituted 2-amino-2-chromenes and 3,4-dihydropyrano[3,2-c]chromenes with excellent yields through a one-pot three-component reaction of aromatic aldehydes, malononitrile, and activated phenols in aqueous media. This environmentally benign protocol was found to be fairly efficient and offer wide substrate flexibility. The basic ionic liquid could be reused several times without any obvious loss of catalytic activity.Graphical Abstract

Synthesis of a Novel Diol-Functionalized Poly(ethylene glycol)-Bridged Dicationic Ionic Liquid and its Application in Copper-Catalyzed Amination of Aryl Halides

A novel diol-functionalized poly(ethylene glycol)-bridged dicationic ionic liquid ([diol-PEG1000-DIL][PF6]) is prepared and used as an efficient and reusable ligand for copper-catalyzed amination. A variety of aryl iodides and aryl bromides reacted smoothly with aqueous ammonia to afford the corresponding aromatic primary amines in good to excellent yields. It is remarkable that aryl chlorides with a strong electron-withdrawing group exhibited a dramatically elevated activity in the presence of tetrabutylammonium bromide. Furthermore, the catalyst could be easily recovered and reused without obvious loss of catalytic activity after five recycling runs.

A facile synthesis of deuteroporphyrins derivatives under ultrasound irradiation

A facile, efficient and general method for preparing deuteroporphyrin derivatives by using concentrated H(2)SO(4) and alcohol under ultrasound irradiation has been developed. A series of new deuteroporphyrin derivatives bearing different propionic ester groups have been synthesized in good yields starting from readily accessible deuterohemin. The characterization of these compounds confirms the synthetic methodology. Compared with conventional methods, the main advantages of the present procedure are shorter reaction time and higher yields.

Synthesis and catalytic properties of a series of cobalt porphyrins as cytochrome P450 model: the effect of substituents on the catalytic activity

A series of cobalt porphyrins derived from hemin was prepared as cytochrome P450 models. Effects of substituents at the cobalt deuteroporphyrin-propionate side chains are investigated in oxidation of toluene with air to benzaldehyde and benzyl alcohol without the use of solvent and sacrificial co-reductant. The catalytic activity of cobalt porphyrins depends on the type of substituents. When the electron-withdrawing groups like –Cl, –Br, were introduced into the double propionate side chains, they can increase the catalyst stability and selectivity to benzaldehyde. In comparison with these electron-withdrawing groups, the electron-donor groups, such as –CH3, –S–S– and –NH2 groups, can improve their catalytic activities. Moreover, the electron-donor group containing an unpaired electron (such as –S–S–, –NH2) is benefit for improving its catalytic efficiency and promoting the electron delivery. It can be concluded that the double propionate side chains in the deuteroporphyrin complex may participate in oxidation process and effect electron transfer from the high-valent metalloporphyrin species to the substrate.

Structure and properties of 1-amino-2-nitroguanidinium nitrate

A nitrogen-rich energetic material 1-amino-2-nitroguanidinium nitrate (ANGN) was synthesized and fully characterized by nuclear magnetic resonance, infrared spectroscopy, mass spectroscopy and elemental analysis. Its thermal behavior and detonation properties were also investigated to give a better understanding of its physical and chemical properties. The results show that the calculated critical temperature of thermal explosion, entropy of activation, enthalpy of activation, free energy of activation, detonation pressure and detonation velocity are 319.8 K, 130.24 J mol−1 K−1, 155.45 kJ mol−1, 106.45 kJ mol−1 43.0 GPa and 9775 m s−1, respectively. It is predicted that ANGN possesses excellent energetic properties compared to those of RDX and HMX, and can be considered as a potential energetic material.

Synthesis, crystal structure and properties of energetic complexes constructed from transition metal cations (Fe and Co) and ANPyO

Two transition metal energetic complexes with ligand 2,6-diamino-3,5-dinitropyridine-1-oxide (ANPyO) have been synthesized and structurally characterized by FT-IR spectroscopy, elemental analysis and single-crystal X-ray diffraction. The thermal decomposition processes and the kinetic parameters of the two complexes were studied by means of the TG-DTG and DSC technologies. The compatibility of the two complexes with RDX (1,3,5-trinitrohexahydro-1,3,5-triazine), HMX (octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine), NC and Al powder was also investigated. DSC measurements show that both complexes have significant catalytic effects on the thermal decomposition of ammonium perchlorate. Sensitivity tests reveal that the two complexes are more insensitive to mechanical stimuli than ANPyO.

Multi-sensitive copolymer hydrogels of N-isopropylacrylamide with several polymerizable azobenzene-containing monomers

Three kinds of photosensitive and two kinds of photo/pH-sensitive polymerizable azobenzene-containing monomers were designed and synthesized. Three thermo/light dual-responsive and two thermo/light/pH triple-responsive copolymer hydrogels were prepared via copolymerization of those new azobenzene-containing monomers, N-isopropylacrylamide, and a crosslinker. The properties of those hydrogels were researched carefully by UV–Vis absorption spectrometry, differential scanning calorimetry, and gravimetry. It was found that the molecular structure, i.e., the methylene chain length, quaternary ammonium group and carboxyl group of azobenzene-containing monomers, had an important influence on the UV light response rate, phase transition and swelling ability of the copolymer hydrogel. Three hydrogels with good overall performances were screened, i.e., GelNDEP, GelNAEP0.01 and GelNAP0.01, which should be used as carriers in later studies. Analysing the influence of the molecular structure will help to fine-tune such a copolymer gel to a desired state, which is very important from an applications point of view.