Dimethyl Carbonate Instead Of Phosgene Synthesis Of Toluene Diisocyanate 2,4 - Toluene Dicarbamate Synthesis

2,4-Toluene Dicarbamate(TDC) is synthesized from 2,4-Toluene Diamine and Dimethyl Carbonate(DMC) instead of phosgene ,which is called as green chemistry substance. And then Toluene Diisocyanate(TDI) is prepared by decomposition of TDC.This synthesis route has some distinct advantages,such as moderate conditions,unexpensive catalyst and methanol as the only by-product.If it is combined with the synthesis of DMC by gas-phase oxidative carbonylation of methanol,the high atom economics process can be acquired.So it is a prospective route for further development in clean production .The following research work concerning the process of TDC synthesis from DMC and 2,4-Toluene Diamine(TDA)has been systematically done in this thesis. Firstly,the purified product of TDC was prepared through multiple crystallization.Its purity was proved by CHN elemental analysis appratus.And qualitative analysis was done by advanced measuring and test instrurnents,such as MS,IR,NMR.The purified product of 2-methyl-5-amino phenyl carbarnate was prepared by liquid preparative chromatography.Purity proof and qualitative analysis were achieved by MS,IR and HPLC.Qualitative analysis of polyurea by-product was done by LC/MS.Therefore,the qualitative determination of all reaction products from DMC and TDA was realized. Secondly, a set of suitable and effective HPLC analysis conditions were set up.As following: chromatographic collum: RP-C1 8,mobile phase: V(CH3OH ): V(H20)=50:50,flow speed: O.6m1/min,wavelength of ultraviolet detector: 254 nxn.Quantitative analysis of TDC was carried out by external standard method.The precision and rate of recovery test were done and the results were excellent. Thirdly ,the catalysts were sifted .The order of activity is as follows: Zn(CH3COO)2. 2H20>PbO>CH3ONa>5ZnO. 2C03. 4H20>Cu(CO32Cu(OH)2. H20=ZnO. Among then, Zn(CH3COO)2. 2H20, PbO and CH3ONa have much higher activity to the III TDC synthesis reaction. Fourthly,the study on synthesis of TDC from DMC and TDA using CH3ONa as catalyst was carried out.It was found that TDC yield was improved obviously when methyl formate was added as a promotor. Quantitative analysis of 2,4-Toluene Diformamide and N-(2-methyl-5-amino)phenyl formamide were completed .According to this,reaction scheme was discussed . The influence of various operating parameters on tbe process were investigated .Optimal operating conditions were determined and the yield of TDC up to 59.75%(based on TDA)could be reached under these operating conditions. Fifthly, the study on synthesis of TDC from DMC and TDA using Zn(CH3COO)2. 2H20 as catalyst was carried out. .The influence of various operating parameters on the process were investigated .Optimal operating conditions were determined and the yield of TDC up to 89.32%(based on TDA)could be reached under these operating conditions.It was found that by XRD and GCIMS the deactiviation of catalyst was due to its reaction with methanol by-product.In addition,which resulted in methyl acetate ,water and Zinc oxide.However,Znic oxide had no activity to TDC synthesis reacticmn.It was determined that the remaining pressure in the autoclave after reaction was due to carbon dioxide resulted from hydrolysis of DMC. Finally,the study on synthesis of TX from DMC and TDA using PbO as catalyst was carried o...