Design, Synthesis, And Solid-liquid Phase Equilibrium Of Phosphate-and Cyanuric Chloride-based Flame Retardants

In today's society, the development of polymer materials which is closely related to the people's life has received the increasing attention. However, polymers are inflammable and suffer all kinds of mandatory controls for security reasons, which limits their commercial use and thus bring our life inconvenience. To minimize the cost caused by fire hazards and expand the range of application of the polymer materials, flame retardant additives have become the center of attention. Flame retardant additives doped in polymer materials can effectively retard or inhibit the combustion of polymer materials. It not only can be more environmentally friendly than traditional flame retardants, but also has good flame retardation.In this paper, two kinds of flame retardant additives were synthesized successfully, and its structure was characterized by infrared spectroscopy and nuclear magnetic resonance.A series of nitrogen-phosphorus compounds were synthesized with the Phenol as carbon source, phosphorus oxychloride as acid source and nitrogen-containing compounds as gas source. The reaction conditions of the synthesis of tetraphenyl piperazine-1, 4-diyldiphosphonate was optimized.In this paper, Solid-liquid phase equilibrium of tetraphenyl piperazine-1, 4-diyldiphosphonate in pure solvents and mixture solvents were measured.The solubilities of TPPDP in dichloromethane, acetic acid, ethyl acetate, acetone, n-hexane, 1-butanol, 2-propanol and isopropyl ether have been determined at temperatures from 283.15 K to 323.15 K using a static analytic method. Molecular modeling and Scatchard-Hildebrand model were employed to discuss the obtained results and reveal the relationship of solubilities and structures of solvents. The modified Apelblat equation, Wilson model and NRTL model were used to correlate the solubility data, in which the Wilson model presents the best fitting results. Furthermore, nonrandom two liquid segment activity coefficient(NRTL-SAC) model with four types of conceptual segments was used for solubility prediction and exhibited a good agreement with experimental data except for acetic acid system. Finally, the molar Gibbs free energy, enthalpy, and entropy of solution were predicted based on the modified Apelblat equation.The solubilities of tetraphenyl piperazine-1, 4-diyldiphosphonate(TPPDP) in(dichloromethane + ethanol) and(dichloromethane + n-hexane) were measured at temperatures from(283.15 to 308.15) K using a static analytic method. Experimental data are well represented by the modified Apelblat and(CNIBS)/Redlich–Kister equations for describing the effects of temperature and solvent composition on solubility, respectively. It was found that TPPDP solubility in dichloromethane + n-hexane decreases with the addition of n-hexane, whereas it shows a maximum in dichloromethane + ethanol. The solubility data are well correlated by Wilson, NRTL, and Jouyban–Acree models, in which Jouyban–Acree model achieves the best fitting results. Based on the modified Apelblat equation, the thermodynamic properties(i.e., the Gibbs free energy, enthalpy, and entropy) of solution in two binary solvent mixtures were derived. The results indicate that the dissolution of TPPDP in all studied cases is not spontaneous and energetic predominance.