Study On Electrochemical Synthesis Of Dimethyl Carbonate From Carbon Dioxide And Chloromethane

In the 21 st century, with the development of economy and society, industry has been developing rapidly. Carbon dioxide level in the Earth is increasing. It results in sharp changes in the earth’s temperature and becomes a serious global environmental problem. It has caused great concern to the world’s scientific research to explore how to effectively control the atmosphere carbon dioxide content. There are great appeal and market potential in developing environment-friendly green products. Therefor, dimethyl carbonate, as non-toxic and new “green” chemical raw materials, stands out. Electrochemical reduction method is used to make the abundant, widely distributed carbon dioxide and methyl chlorine synthesize dimethyl carbonate in a single room sealed electrolytic cell by electrolysis. It has a very important significance for the electrochemical reduction to the use of the carbon cycle and environment protection. Therefor, it has a broad development potential in the future for the electrochemical reduction of carbon dioxide to synthesize dimethyl carbonate.CO2 is one of the main gases to make global warming and cause the "greenhouse effect". It is also a waste gas of industries emission. It results in a serious threat to the survival of the human environment and the ecosystems on Earth. However, CO2 is also a potential carbon resource. It has great significance for electrochemical method to be used to synthesize dimethyl carbonate, whether from an environmental point of view or the energy point of view.Based on the previous research synthesizing dimethyl carbonate from carbon dioxide, the technological conditions affecting the yield and selectivity of in electrolytic process were explored in this thesis. The optimum rection conditions were further searched. The researches were as following:1. Selection of the electrode material and electrolytic solution of electrochemical synthesizing dimethyl carbonate: During electrolysis, the cathode was copper and introduced by CO2 gas. The anode was lead and introduced by methane gas. The electrolytic solution was sodium chloride. Electrolytic process was taken in an electrolytic cell.2. The yield Calculation and testing conditions of electrochemical synthesizing dimethyl carbonate:(1) Gas chromatography-single point calibration method and the orthogonal experiment method were used to calculate the yield of dimethyl carbonate,(2) Based on nature of dimethyl carbonate, a gas chromatography-mass spectrometry were adopted to measure dimethyl carbonate.3. Research on reaction mechanism of electrochemical synthesizing dimethyl carbonate from carbon dioxide and methane:(1) In the electrolysic process, the cathode was copper and introduced by CO2 gas. The activated chlorine radical was directly free from chloride solution because chlorine had higher activity. CO2 was an inert gas of small molecules and its properties were very inactive. If it was wanted to take organic synthesis reaction, it should be activated to become activated carbon radicals.(2) The anode was lead and introduced by methane gas. The activated chlorine radical took rection with methane on electrode to form methyl chloride. Then the methyl chloride took rection with the activated carbon radicals to synthesize dimethyl carbonate.