【作者】 曹育才；

【导师】 姜玄珍；

【作者基本信息】 浙江大学 ， 化学， 2002， 博士

【摘要】 二氯二氟甲烷CCl2F2五氟氯乙烷CClF2CF3和四氯化碳CCl4三种氟氯烃的脱氯加氢被用作研究几类新型加氢脱氯催化剂催化性能的模型反应新型催化剂包括负载型PdCl2-(n-C4H9)4N+Cl-熔融盐以钯配合物为前驱体制备的负载型钯催化剂负载型钯酞菁催化剂和镓修饰的负载型铂催化剂新型的负载型液膜催化剂负载型PdCl2-(n-C4H9)4N+Cl-熔融盐催化剂首次被用于催化CCl2F2的选择性加氢脱氯反应生成产物主要为具有良好商业应用前景的CH2F2和CHClF2在优化的反应条件下CH2F2 + CHClF2的选择性可达80以上同时该催化剂在广泛的H2/CCl2F2 0.25-10范围内具有良好的催化稳定性熔融盐介质中添加GaCl3和CuCl2能提高负载型PdCl2-(n-C4H9)4N+Cl-熔融盐催化下CCl2F2向CH2F2 + CHClF2转化的选择性遗憾的是该催化体系中CCl2F2向CH2F2或CHClF2单一产物转化的选择性较低< 50有必要进一步探索对单一产物特别是CH2F2生成具有高选择性的催化剂本文率先在负载型钯酞菁催化剂上实现了CCl2F2加氢脱氯向CH2F2的选择性转化微分反应条件下以氟化物MgF2和AlF3为载体的催化剂PdPc/MgF2和PdPc/AlF3上CH2F2的选择性分别可达80.0和76.0与负载型PdCl2-(n-C4H9)4N+Cl-熔融盐相比负载型钯酞菁催化剂上单一产物CH2F2的选择性有了较大的提高在低H2/CCl2F2摩尔比2 : 1和含HCl和HF等酸性物质的催化反应条件负载型钯酞菁催化剂在上述反应中能够保持良好的催化稳定性酞菁环能够在反应条件下保持结构稳定酞菁环对Pd催化活性相的修饰作用是催化剂保持良好催化稳定性的主要原因进一步的研究揭示部分还原的钯为催化加氢脱氯的活性中心合成了新型的钯有机配合物二氯二(三苯基膦)钯DCTPPP和二硫氰根二(三苯基膦)钯DTTPPP创新性地作为制备新型负载型钯催化剂的前驱体进一步研究了新型负载型钯催化剂上CCl2F2的选择性加氢脱氯反应结果表明在微分反应条件下DCTPPP/MgF2和DTTPPP/MgF2催化剂上CH2F2的选择性分别可达88.1和85.8催化稳定性考察揭示DCTPPP/MgF2和DTTPPP/MgF2催化剂上CCl2F2加氢脱氯反应能够保持稳定达60小时以上CCl2F2加氢脱氯中新型负载型钯催化剂具有高催化活性高CH2F2选择性和良好的催化稳定性主要归因于钯活性相的高分散度90以CrF3首次作为加氢脱氯催化剂载体研制了负载型钯催化剂DCTPPP/CrF3和Pd/CrF3与普通的Pd/γ-Al2O3催化剂相比较以CrF3为载体的新型负载型钯催更多还原

【Abstract】 Dichlorofluoromethane (CCl2F2), chloropentafluroethane (CClF2CF3) and tetrachloro-methane (CCl4) were chosen as the model reactants to evaluate the catalytic activity for selective hydrodechlorination over several novel supported catalysts e.g. supported PdCl2-(n-C4H9)4N+Cl- molten salts, supported palladium phthcyanine catalysts, supported palladium catalysts prepared through organometallic palladium compound as precursors, and supported gallium modified platinum catalysts as describled in follows:A novel supported liquid phase film catalyst, supported PdCl2-(n-C4H9)4N+Cl- molten salts was firstly found to be an effective catalyst with good stability for selective hydrodechlorination of CCl2F2 (CFC-12) to its alternatives CH2F2 and CHClF2. the selectivity of more than 80% for CH2F2+CHClF2 was achieved under optimized reaction conditions. Addition of GaCl3 and CuCl2 to PdCl2-(n-C4H9)4N+Cl- supported molten salts was beneficial to improve the selectivity to CH2F2+CHClF2.Supported palladium phthalocyanine was also found to be an interesting catalyst with good stability for selective conversion of CCl2F2 into CH2F2 under flowing hydrogen further. Relatively high selectivities towards CH2F2 formation over palladium phthalocyanine catalysts with fluoride supports were achieved at limited conversion levels (<10%). Particularly, supported palladium phthalocyanine exhibited excellent stability even at low H2/CCl2F2 ratio in the corrosive reaction conditions due to the formation of HCl and HF. The fractionally reduced palladium in palladium phthalocyanine was suggested to be the main active site for the catalytic hydrodechlorination. Moreover, novel supported palladium catalysts were prepared through organometallic Pd compounds including dichlorobistriphenylphosphine palladium (DCTPPP) and dithiocyanatobistriphenylphosphine palladium (DTTPPP) for the hydrodechlorination of CFC-12 for the first time. These catalysts exhibited excellent catalytic activities in hydrodechlorination of CFC-12. Particularly, high selectivities of CH2F2 formation were achieved over the catalysts, DCTPPP/MgF2 with 88.1% and DTTPPP/MgF2 with 85.8%, at a limited conversion level (<5%). No obvious deactivation was observed for DCTPPP/MgF2 and DTTPPP/MgF2 catalysts within 60 hours. The higher catalytic activity, CH2F2 selectivity and catalyst stability may be mainly attributed to high dispersions of palladium.Additionally, novel CrF3 supported palladium catalysts have been prepared through two different precursors i.e. dichlorobistriphenylphosphine palladium (DCTPPP) and更多还原