【作者】 金中豪；

【导师】 卢冠忠； 王幸宜；

【作者基本信息】 华东理工大学 ， 工业催化， 2010， 博士

【摘要】 4,6-二氨基间苯二酚(DAR)是制备高性能纤维PBO的单体,开展DAR合成工艺的研究具有重要的意义。本论文以2-氯-4,6-二硝基间苯二酚为原料,10 wt.% Pd/C为催化剂一步加氢脱氯、硝基还原反应合成DAR。通过比较晶状DAR的产量以及2-Cl-DAR副产物的含量,研究反应过程中的溶剂效应,确定了乙醇-水混合溶液为最合适的反应介质。并对乙醇-水介质中,2-氯-4,6-二硝基间苯二酚催化加氢合成DAR的工艺条件进行了优化,提出在乙醇-水介质中适宜的工艺条件：10 wt.% Pd/C催化剂2.5 g,2-氯-4,6-二硝基间苯二酚60g、80%乙醇-水溶液600 ml,乙酸铵20.0 g,2.2 MPa氢压,1300rpm搅拌速率。当起始反应温度为40℃时,得到晶状DAR 37.8 g,其中2-Cl-DAR副产物含量为0.37%。又以2-氯-4,6-二硝基间苯二酚为硝基苯酚类化合物的模型底物、丙酮为烷基化剂、氢气为还原剂,研究了10 wt.% Pd/C催化的一锅法还原N-单烷基化反应和加氢脱氯反应合成4,6-二(异丙基氨基)-1,3-苯二酚(BPAR)的反应工艺。通过改变醋酸的添加量、反应时间、溶剂的组成、氢压以及催化剂用量,考察了工艺条件对产物BPAR的得率及选择性的影响,选出最优操作条件为：10 wt.% Pd/C催化剂2.0 g,醋酸20ml,2-氯-4,6-二硝基间苯二酚40g、1：1(v/v)丙酮/异丙醇320 ml,水50ml,乙酸铵13.3 g,2.0 MPa氢压,1300 rpm搅拌速率,反应时间90 min, BPAR的得率为91%。以上述反应工艺为基础,考察了多种硝基苯酚类衍生物与酮类化合物生成相应的仲氨基苯酚化合物；而以醛为烷基化试剂时,双烷基化的叔胺基苯酚则是唯一的烷基化产物。负载型钯催化剂参与的液相催化加氢脱氯反应不仅能用于有机化合物的合成,同时也可以非破坏性的方法用于氯代芳烃的处理,因此,研究催化剂中钯活性位的结构特征与制备方法的关系对氯代芳烃的低温加氢脱氯反应具有重要的科学意义和应用价值。本论文选用介孔C-SiO2复合材料(MSC)、Si02基有序介孔分子筛(SBA-15)和活性炭(AC)三种不同载体负载的钯催化剂(Pd/MSC、Pd/SBA-15和Pd/AC),运用低温N2吸附/脱附、XRD、H2-TPR、H2-TPD、XPS、HR-TEM等技术,研究了这三种催化剂的结构特征。由HR-TEM确认MSC负载的Pd/MSC中Pd晶粒表面存在大量台阶状缺陷的晶界结构,Pd/SBA-15中Pd晶粒表面平整,而Pd/AC中同时存在大量表面平整的Pd和少量缺陷的Pd。在低温(-15℃)条件下,以Et3N为碱助剂,以4-氯苯酚(4-CP)、2-氯苯酚(2-CP)和2,4-二氯苯酚(2,4-DCP)为氯苯酚化合物模型分子,研究了Pd/MSC、Pd/SBA-15和Pd/AC液相加氢脱氯反应的催化活性和选择性。催化剂的活性取决于其具有缺陷结构Pd的含量,以缺陷结构Pd为主体的Pd/MSC表现出最高的催化活性,而以平面Pd为主体的Pd/SBA-15活性较低。使用DFT理论计算的方法得到了Et3N、4-CP和2,4-DCP在Pd(111)平台面(模拟平面结构Pd)和Pd(211)台阶棱(模拟缺陷结构Pd)上σ键和π键配位吸附构型的吸附能。关联Pd的结构特征及实验数据,发现4-CP通过苯环在这两种结构Pd活性位上形成π键吸附被活化；有空间位阻的2,4-DCP在Pd/MSC上通过4位氯的σ键配位吸附活化,表现出对中间物种2-CP的绝对选择性。而在Pd/AC和Pd/SBA-15催化的反应中,2,4-DCP仍通过苯环与Pd活性位形成π键吸附被活化,中间物种2-CP和4-CP同时生成。Et3N阻抑作用可归结于其在Pd活性位上的吸附能与反应物分子的吸附能相当。降低Et3N的浓度,可明显降低其阻抑作用。更多还原

【Abstract】 It is significant to investigate the methods for the synthesis of 4,6-diaminoresocinol (DAR) that is the indispensable monomer used in preparing the high-performance fiber PBO. In this paper, DAR was synthesized by catalytic HDC and nitro reduction of 2-chloro-4,6-dinitroresorcinol over 10 wt.% Pd/C catalyst. The solvent effect on the yield of DAR and the content of 2-Cl-DAR byproduct was studied, and the ethanol-water mixture was considered as the most appropriate reaction media. The operation conditions of catalytic reaction were optimized, and the optimum operation conditions were obtained:2.5 g of 10 wt.% Pd/C catalyst,60.0 g of 2-chloro-4,6-dinitroresorcinon and 20.0 g of ammonium acetate, 600 ml of 80% ethanol-water solution, a stir of 1300 rpm, hydrogen atmosphere of 2.2 MPa. At the initial reaction temperature of 40℃,37.8 g of DAR was obtained with 0.37% 2-Cl-DAR byproduct.4,6-bis(isopropylamino)resorcinol (BPAR) was catalytically synthesized from 2-Chloro-4,6-dinitroresorcinol by an one-pot reaction including reductive mono-N-alkylation and HDC over 10 wt.% Pd/C catalyst, in which acetone was used as alkyl source and hydrogen as reducing reagent. The effects of reaction conditions, such as the amount of acetic acid, reaction time, solvent, hydrogen pressure and catalyst amount, on the yield of BPAR were investigated. The optimum operation conditions were obtained as follows:2.0 g of 10 wt.% Pd/C catalyst,20 ml of acetic acid,40.0 g of 2-chloro-4,6-dinitroresorcinon 320 ml of 1:1 (v/v) acetone/2-propanol mixtures,50 ml of water,13.3 g of ammonium acetate, hydrogen atmosphere of 2.2 MPa, a stir of 1300 rpm. In the reaction condition above the synthesis reaction was carried out for 90 min,91% of BPAR yield was obtained.When various nitrophenol derivatives were used as the reactant and ketone as alkyl reagent, the corresponding secondary alkyl aminophenols with the high yield were achieved by a one-pot catalytic synthesis method in above operation condition over 10 wt.% Pd/C catalyst. When aldehyde was used as the alkyl reagent, the corresponding tertiary amine as a sole N-alkylation product was obtained.Liquid phase HDC catalyzed by supported Pd catalyst is considered as an economical and environmentally benign method in the synthesization of organic compounds as well as the nondestructive disposal of chlorinated arene. It is significant to investigate the correlations between the structure of Pd active sites and the performance of Pd catalyst for the HDC of chlorinated arene.Three different carriers, mesoporous silica-carbon nanocomposites (MSC), mesoporous SiO2 (SBA-15) and active carbon (AC) were employed as the supports of Pd catalyst (noted as Pd/MSC, Pd/SBA-15 and Pd/AC, respectively). The textural properties of the supports and catalysts have been determined by the low temperature N2 adsorption/desorption, XRD, H2-TPR, H2-TPD, XPS, HR-TEM. The results show the nano-sized Pd particles with the saw-edged grain boundaries formed on Pd/MSC due to the unique hybrid nature of carbon and silica. The mainly isolated Pd particles with terrace formed on Pd/SBA-15 and Pd/AC were observed, and a small quantity of Pd defect existed on Pd/AC.In the HDC of chlorophenols at low temperature (-15℃), the activity of catalyst depends on the content of Pd defect. Pd/MSC with a high concentration of defective surface Pd atoms exhibited the very high catalytic activity, and Pd/SBA-15 with a high concentration of plane surface Pd atoms exhibited the lower catalytic activity.The ab initio Density Functional Theory (DFT) was used to calculate the adsorption energies of Et3N,4-CP and 2,4-DCP by formingπ-orσ-complex on the terrace site of Pd (111) and the step edge of Pd (211), which are to simulate the plane and defective surface Pd atoms. The results show that 4-CP was activated via the formation ofπ-complex with aromatic ring on Pd (111) and Pd (211). It is evident that HDC of 2,4-DCP with steric hindrance over Pd/MSC isn’t similar to the situations over other two catalysts, in which 2,4-DCP adsorbed on the Pd atoms by formingσ-complex with C-Cl bond at 4-position, resulting in the only intermediate specie of 2-CP. The intermediate species of 2-CP and 4-CP were detected simultaneously in the HDC of 2,4-DCP on Pd/AC and Pd/SBA-15 in which 2,4-DCP was adsorbed flatly by the formation ofπ-complex with the aromatic ring.The inhibition of Et3N occurs mainly on Pd/MSC and Pd/AC, because of the competition adsorption with substrates on the defective surface Pd atoms. Reducing the concentration of can relieve the inhibitory effect evidently.更多还原