The Synthesis Of Four Compounds For Seawater Desalinating RO Composite Membrane

As the development of the science and the society, we needs more fresh water to drink and to be provided for the industry and agriculture. Especially in the area besides the sea, the shortcoming of fresh water is hindering the development. So, it is important and urgent to find more water resource. To dissolve the problem, seawater desalinating is a good method.If a choice had to be made, the Reverse Osmosis process would be elected as state-of-the-art in water treatment technology today. Reverse Osmosis (RO for short) was developed in the late 1950's under U.S. government funding, as an economical method of desalinating sea water-a dream long sought after by mankind. Reverse Osmosis is revolutionary because it uses a completely new mechanism for processing water-the semi-permeable membrane. Surprisingly enough, it looks a lot like common household sandwich wrap and is composed of very similar polymers (plastic). PA Composite membrane is a new generation of Reverse Osmosis composite membrane, with the development of the technology; it has becoming the best choice of the seawater desalination. In china, seawater-desalinating technology is underdevelopment. So our work's aim is to prepare several excellent PA monomer and to investigate the technology of these compound's synthesis. Our work is a preparing work of the research for the new good seawater desalinating RO membrane.In our work, We selected four classical compounds, which have important usage for PA RO membrane. They include 5-isocyanatoisophthalic chlorides and cis,cis-1,3,5-tricarboxylcyclohexane acid and 1,3,5-triaminobenzene and trans-1,4-diaminocyclohexane, which are representation of four kinds of excellent PA monomer. Based on summing up the presenced documents about their synthesis method, we synthesis them with the best way.5-isocyanatoisophthalic chlorides is first prepared from oxalic chloride. Our method has many merits over the early method. All the reaction is performed under a general condition: The best reaction temperature is 80-110 centigrade.The pressure of the reaction is common.The toxicity of the reaction is low.Cis,cis-1,3,5-cyclohexanetricarboxyl acid is prepared with Rh/C (5%) as catalyzer and water as solvent under 10-40 atm of hydrogen. Product is prepared with over 95% yield. The trans isomer is separated through recrystalization with ethanol/toluene.1,3,5-triaminobenzene is prepared through three methods, and then we chose the best way as the final method to synthesis the product. We prepare 3,5-dinitroaniline, and then reduce it with Pd/C and hydrogen. All the work is complete in 40 hour, and the yield is 80%. However, the best way to synthesis the product is to reduce the 1,3,5-trinitrobenzene, although this compound is difficult to get.Trans-1,4-diaminocyclohexane is prepared through two methods. One is from 1,4-cyclohexdione and the other is from p-diaminobenzene under hydrogen reducing with Rh/C (5%). The result proved that the latter is more suitable to mass-scaled product. All these four compound's product conditions are investigated carefully. At the same time, the magnify experiment is carried; the result proved that the four way are stable and effective.