| Dimethyl carbonate(DMC) is an important chemicals since twentieth Century, and its synthesis method is the hot spot of research. Direct synthesis of DMC from CO2and CH3OH was still in the initial stage. However with the resources and environmental issues, this synthesis method has received wide attention from researchers. Direct synthesis of DMC from CO2and CH3OH was worthy of our further study. In order to further promote the direct synthesis of DMC, we make efforts in the following aspects:1. CexZr1-xO2(0(?)x(?)1) catalyst(1) First of all, CexZr1-xO2(0(?)x(?)1)showed better catalytic performance, we select ceria-zirconia solid solution as catalyst, the influence of different preparation methods on the catalytic activity of the solid solution of cerium zirconium were evaluated:citric acid sol-gel method, precipitation method.(2) The catalyst prepared by citric acid sol-gel method showed better catalytic performance, the influence of different calcination temperature and cerium zirconium ratio was investigated, and the best cerium zirconium ratio and optimal calcination temperature was1and600℃, respectively. We also explored the suitable reaction conditions as120℃and8MPa. With the increase of the reaction temperature, the yield of DMC increased and then decreased. Reaction pressure also have influence on the reaction, high pressure is favorable to the reaction, but in thesupercritical pressure, reaction effect is not obvious ascension,8MPa as the optimal reaction pressure.(3) The catalysts were characterized by XRD, SEM, Raman, BET, TPR methods. And structures of catalysts were combined with the catalytic performance, cubic phase is more conductive to restore and showed higher catalytic activity. And the repeated use of catalyst deactivation reasons are explored, the main reason for the decrease of acidity.(4) H3PW12O40was used to modified cerium zirconium solid solution for the first time. And the catalytic activity was significantly increased, the catalytic activity of Ce0.5Zr0.5O2increased by48%, the number of acid sites of interaction is benefit to improve, conducive to high catalytic activity.(5) In order to overcome the influence of the thermodynamic limit, DMP was used as dehydrating agent to consumption water generated in the reaction. When DMP was added aapropriatedly, DMC production increased more than6times. The amout of DMP affect the possible reactions and raction results.2. Cu-Ni/CexZr1-xO2 According to the literature study, bifuctional metal catalyst Cu-Ni/CexZr1-xO2was prepared by impregnation method, hich is a new type of catalyst. The metal material Cu-Ni and oxide carrier show cativity to the synthesis of DMC simultaneously. When the metal loading amount was10%, the methanol conversion rate reached5.52%, the yield of DMC was4.85%. In this paper, a new mechanisms in the presence of bifunctional catalysts were puts forward.3. Fixed bracket for water bath and a kind of gas cylinder truck(1) Fixed bracket for water bathDuring the preparation of catalyst, with decreasing solution volume, beaker container easily overturned, even contamination of the sample, and the water bath pot steaming process, prone to dry the danger. A adjustable height, anti-dry bath bracket were designed to solve the problem mentioned above.(2) Gas cylinder truck designA large amount of gas was needed in the process of experiment. It was very difficult to transport gas cylinder in the corridor without elevator. So a stair climbing anti-skid cylinder truck was design. On one hand, the design reducing the labor intensity of gas transport upstairs, on the other hand, ratchet wheel design during transport ensured the transport safety. The planet wheel adopts the structure of five wheels, enlarging the radius, to guarantee the smooth upstairs process. |
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