Preparation of CaO/ZrO2-La2O3 Solid Base Catalyst for Synthesis Di-2-ethyhexyl Carbonate

Preparation of CaO/ZrO2-La2O3 Solid Base Catalyst for Synthesis Di-2-ethyhexyl Carbonate
　　The CaO/ZrO2-La2O3 solid base catalysts were prepared by dipping ZrO2、ZrO2-La2O3 prepared by method precipitation in Ca(NO3)2 solution and calcined at different temperatures. The XRD results showed that CaO and ZrO2 coexisted in solid solution in all of samples at the calcination temperature 400°C～600°C, ZrO2 existed in tetragonal phase, CaZrO3 were generated in several samples and CaZrO3 were generated at 700°C of the samples Cube neodymium magnet addition of lanthanon La.The SEM results suggested that the samples were the abnormal spot adjunct and lots of white minuteness grains were aggregated on their surface.
　　The BET results revealed that the addition of La increased the solid base samples specific surface area, and the specific surface area of 0.2%CaO/ZrO2-La2O3 was 79.26m2/g after calcined at 600°C. The specific surface area was decreased after the lots of CaZrO3 generation.The base strength was studied by Hammett Indicator method, and the results displayed that the maximal base strength was H0=15.0～17.2, therefore it wasn’t solid superbase.The mechanism was discussed that synthesis of di-2-ethyhexyl carbonate by transesterifying with self-made solid base, through the method of changing factor to search for the conditions of catalytic reaction. The best conditions were confirmed that: solid base of 0.2%CaO/ZrO2-La2O3 calcined at 600°C, the catalyst addition is 1.5% weight of dimethyl carbonate and 2-ethylhexanol. The synthesis of di-2-ethyhexyl carbonate was by two-step transesterification, the reactants were stiring and backflow under the boiling point for 2h, then distillating to http://www.chinamagnets.biz/ remove the carbinol, the reaction temperature was rised to 130°C and the reaction was continue for 4h.Under the same reaction condition, comparing with other solid base catalyst, this catalyst had the advantages of high yield of product, easy to recover, better reuse quality, the yield of product was also 58.4% after the catalyst used seven times by multiple retexture.The synthesized samples which were obtained by decompression distillation time after time were analysed by FTIR、1H-NMR. The results indicated that the samples’ structure conformed to di-2-ethyhexyl carbonate. The synthesized samples were designed to quantitative analysis by HPLC, the results showed that CaO/ZrO2- La2O3 solid base played an important role in transesterification, and had good catalystic activity, the yield of product is high.