| As one of aromatic family, polychlorinated polycyclic aromatic hydrocarbons (PPAHs) have important significance in the study of the molecular recognition, carbon cluster and fullences. One hundred years ago, the Beilstein's group designed the synthesis of PPAHs for the first time. From then on, different groups engaged in this study, however, it's very difficult to synthesize PPAHs because of the large volume of chlorine atom and accumulation of them in PPAHs. So searching for suitable synthetical method is the key to succeed in obtaining PPAHs.Mixture of alkali metals with a number of halogenated alkane solvents such as carbon tetrachloride and chloroform can be used to form the C-C bonds between alky groups. For instance, R1X and R2X react with Na to form R1-R2 (the Wurtz-type reaction). However, due to the shock-sensitive and highly explosive according to numerous chemical literatures, such a reaction had rarely been utilized to synthesize the PPAHs in traditional organic synthesis. In view of recent reports, however, the explosion can be avoided if the reaction is taken place in sealed container (solvothermal condition) instead of open vessels. Moreover, this process is capable of application to production of different carbon-based materials including diamond, nanotube, graphite, onion and so on, these show carbon tetrachloride as well as other small halogenated alkanes can be used to synthesize carbon-rich materials with different structures. According to Wurtz reaction, if we can control solvothermal reactive condition to make the four C-Cl bonds in the carbon tetrachloride broken incompletely, according to the mechanism of Wurtz reaction, some kinds of free radicals or carbonium ions will be produced in solvothermal condition. These free radicals or carbonium ions will assembly through some growth rule to form a number of PPAHs. So, it is feasible to synthesize the PPAHs with solvothermal methodDiamond as well as other carbon-based materials with much practical and theoretical significance was synthesized successfully in solvothermal condition, which fully displayed the merit of solvothermal method. In the inorganic synthetical field, the solvothermal method has been applied comprehensively, however, there are no reports inthe organic synthetical field. So if the solvothermal method is used to synthesize the PPAHs, it will have theoretical and practical significance.Based on these successful applications, we try to synthesize PPAHs using sodium and carbon tetrachloride in solvothermal condition, to separate and characterize the solvothermal products and discuss the mechanism of carbon ring.1. By searching the reactive temperature, reactive time and amounts of sodium, the final reactive condition is: 3.0g(0.13mol) sodium and 25ml CCl4 was sealed into the steeless-autoclave with 40ml volume and reacted for 40h in 300.2. High performance liquid chromatography coupled with both mass spectra and ultraviolet absorption spectroscopy were investigated for the separation of solvothermal products. More than fifty PPAHs were isolated successfully on C18 column with a methanol-cyclohexane gradient mobile phase. According to mass feature of PPAHs and chlorine isotopes patterns in the mass spectra, the formula of these PPAHs was given. Sixteen pure PPAHs were obtained by sublimation, neutral Al2O3 column chromatography, and recrystaliztion and preparative high performance liquid chromatography.3. Preparative high performance liquid chromatography conditions were investigated for the separation of solvothermal products. Many PPAHs were separated and purified on the C18 column with toluene-methanol mobile phase.4. Among sixteen pure PPAHs C6C16, C10Cl8, C12Cl10. C13Cl8O, C15C18O,(two isomers) , C26Cl8O2H2. C26Cl10H8, C39Cl10, twelve new PPAHs are identified by X-ray single diffraction, infrared spectra, ultraviolet spectra, mass spectra and nuclear magnetic resonance spectra. The structures of six new PPAHs C15Cl8O, (C16Cl10) 2CS2. C18Cl122O2, C19C19OH, C26Cl8O2H2,... |
PDF Full Text Request