In order to solve the unclear problems of structure and composition for 2,4-dihydroxybenzoic acid (2,4-DHBA) copper salt (β-Cu), a new insoluble ternary copper (Ⅱ) complex of 2,4-DHBA ([Cu(C12H8N2)2(C7H5O4)](C7H5O4)) was designed and synthesized in water. The ternary complex crystallizes in the monoclinic system with the space group P21/n. The central Cu2+ is coordinated with four nitrogen atoms from two 1,10-phenanthroline ligands and one carboxyl oxygen atom from a 2,4-DHBA anion. The other 2,4-DHBA anion does not participate in coordination and only provides the action of balance charge. In addition, compared with β-Cu, no water molecules exist in the ternary complex. The thermal stability of the ternary complex was investigated, as well as its catalytic decomposition activity on AP and RDX. With the addition of the ternary complex, the exothermic decomposition peak temperatures of AP and RDX were reduced from 406.5 to 353.9 °C, and 242.3 to 181.4 °C respectively, and the apparent activation energies were reduced from 293.1 to 207.4 kJ mol−1, and 239.6 to 177.5 kJ mol−1, respectively. Moreover, the addition of the ternary complex has greatly improved the heat release of AP and RDX. The catalytic decomposition performance of the new ternary complex on AP and RDX is much better than that of the traditional β-Cu. Moreover, the new copper (Ⅱ) complex completely changed the thermal decomposition process of RDX from melting decomposition to direct solid phase decomposition, and such catalytic effect is uncommon. Therefore, the new ternary copper (Ⅱ) complex presents a better potential application for modified double-base propellant of RDX.
- 2,4-Dihydroxybenzoic acid
- Catalytic decomposition activity
- Crystal structure
- Ternary copper complex