The Simulation And Research Of Synergistic Reaction In Near-Critical Water

As a new chemical engineering technology, near critical water (NCW) technology is earning great attention from the theoretical research and engineering applications in recent years, and various state-equations have been applied in phase-equilibrium calculation for the NCW mixing system. However, there are lacks in the relationship between micro structure and macro nature of NCW, as well as the organic reaction mechanism in the theoretical research in NCW, significantly limiting the development and applications of this technology.Against the lacks of the theoretical studies on the reactions in NCW, we chose Rupe and Meyer-Schuster rearrangement reactions, as well as geraniol and linalool multiple product reactions as model reactions, quantized simulation was introduced to study the reactions in NCW, and a model was built to investigate the reactions occurring in NCW. We advised a point that the partially synergistic reactions in NCW may be achieved though the acid-base catalytic reaction mechanism rather than the acid catalytic mechanism. The article mainly includes the following aspects:1. A model of calculation simulation was established, which can be used to study the NCW reactions. This model divided the NCW influences on the reactions into two parts. One is the environment effect of NCW on the reaction, the other is the effect of the water molecules aroud the functional group. The results demonstrated that the influence of the water molecules close to the functional groups exceeded that of NCW environment.2. The acid-base catalytic reaction mechanism in NCW was put forward. The reactants with unsaturated group (double bond and triple bond) and hydroxyl groups therein simultaneously have different reaction pathways in water and NCW. One is acid catalytic pathway in ordinary state water, and the other is maybe acid-base catalytic pathway in NCW due to its special properties.3. Rupe rearrangement reaction was investigated systematically, using1-ethynyl-1-cyclohexanol as model reactant. The two pathways (water molecules and hydroxyl ions attacking the IM) were calculated. The results showed the more-easily-proceeded is acid-base catalytic reaction, where the hydroxyl ions attack the IM directly to form the product. Furthermore, it was found that the transition state has three-number-ring structure, and it is different from the reported structure.4. Meyer-Schuster rearrangement reaction in NCW was investigated systematically, using1-ethynyl-1-cyclohexanol as a model reactant. The reaction feasibility was analyzed by frontier orbital theory, and then the acid catalytic reaction pathway and acid-base catalytic reaction pathway were calculated. The results showed the acid-base catalytic reaction proceed more easily in NCW.5. Useing geraniol multiple product reaction as model reaction, the reaction pathway in NCW was studied systematically. The possibility of the reaction was analyzed by frequency and frontier orbital theory, and then the reaction pathway was investigated. The results showed that the essence of the reactions is still acid-base catalytic reaction, although there are many products can be achieved through different reaction paths, and acid-base catalytic reaction proceeded easier. In the reaction, the influence of the number of water molecules (in the range of3-7) on the zero-point energy was calculated, and the regulation about the water molecules close to the functional groups influencing the energy barrier was also obtained. Meanwhile, the influence of the NCW environment on the reaction was analyzed using dielectric constant as parameters. The results demonstrated that the influence of the water molecules close to the functional groups on the reaction exceeded that of NCW environment.6. We use linalool multiple product reaction as model reaction to study the reaction pathway in NCW. The method and conclusions were similar with geraniol multiple product reaction.7. The related regulation was obtained by combining the Rupe rearrangement reaction data obtained from the computational simulation and experimental study in NCW. Moreover, the main emphasis of the future work was also determined.