氯铝酸室温离子液体系中HCl促进的苯的烷基化反应研究

研究了少量HCL调变的氯铝酸室温离子液体超强酸催化体系中，苯与碳-12烯以及氯甲烷的烷基化反应，对于前一反应，以溶有HCL的氯铝酸室温离子液体为催化剂与没有HCL的相比，反应的产物分布不同，而后一反应过程中有HCL生成，与纯ALCL3作催化剂相比，催化活性显著提高，实验结果还表明，生成的烷基化产物不溶于离子液体，因而易于分离，催化剂可以重复使用。     

SO42-/ZrO2-TiO2催化苯与1-十二烯烷基化合成十二烷基苯

利用沉淀-浸渍法制备了SO42-/ZrO2-TiO2固体酸催化剂,优化了SO42-/ZrO2-TiO2催化苯与1-十二烯烷基化合成十二烷基苯的工艺条件,并通过IR及GC/MS对产物的结构进行了表征.结果表明: SO42-/ZrO2-TiO2对苯与1-十二烯的烷基化反应具有良好的催化性能,其催化中心主要为B酸中心.0.12g催化剂/ mL1-十二烯、n(苯)/n(烯)=6:1、反应时间3 h等优化条件下1-十二烯转化率100%,LAB与2-LAB选择性分别达到90.3%和88.6%.使用后的催化剂可以通过H2SO4浸渍500 ℃焙烧再生.GC/MS分析表明产物主要包括2～6-LAB及少量二烷基苯.     

MCM-36分子筛的合成及其苯与丙烯烷基化性能研究

分别从MCM-22和MCM-49前驱体出发合成了MCM-36分子筛, 在液-固固定床反应器上对MCM-36分子筛的苯与丙烯液相烷基化反应性能进行了评价. 由MCM-22前驱体出发合成的MCM-36(A) 结晶度良好, 比MCM-22具有更高比表面积和介孔孔容, 酸量明显下降. 由MCM-49前驱体出发合成的MCM-36(B)的比表面积和介孔孔容增加, 小角XRD特征衍射峰强度低于MCM-36(A), 与MCM-49相比酸量下降幅度较小. 在苯与丙烯液相烷基化反应中MCM-36(A)的活性与MCM-22相当, 丙烯的转化率大于99.5%, 异丙苯的选择性比MCM-22提高了7%. MCM-36(B)的反应活性高于MCM-36(A), 而异丙苯的选择性低于MCM-36(A). MCM-36分子筛上苯与丙烯液相烷基化反应活性的提高归因于有效酸性位的增加,异丙苯选择性的提高则主要归因于B酸量的降低.     

水热处理对MCM-22催化剂酸性、孔结构及甲苯/甲醇烷基化性能的影响

采用XRD, NH3-TPD, IR和低温氮气吸附等方法研究了分别以纯水蒸气和质量分数为6％的氨水蒸气处理MCM-22分子筛催化剂后, 其酸性和孔结构的变化, 并以甲苯、甲醇烷基化为探针反应考察了催化剂的催化性能. 研究结果表明, 在两种不同介质中和处理温度不高于400 ℃条件下, 催化剂的总酸量变化不大, 强酸中心有所增加; 处理温度高于500 ℃后, 催化剂的总酸量明显下降, 强酸中心基本消失; 经水热处理后, MCM-22分子筛催化剂中形成了孔径不均匀的二次孔, 平均孔径增大. 随着处理温度的提高, 催化剂的活性降低, 对二甲苯和邻二甲苯的选择性上升. 经500 ℃纯水蒸气处理5 h的MCM-22催化剂, 具有适宜的酸强度和酸类型分布, 有利于甲苯甲醇烷基化反应的进行, 且催化剂维持了较高的催化活性并具有一定的对位选择性(甲苯转化率和对二甲苯选择性分别29.22％和42.16％).     

脱铝MCM-49分子筛的结构、酸性及苯与丙烯液相烷基化催化性能研究

采用硝酸回流和水蒸气两种处理方法对用动态水热法合成的纳米MCM-49分子筛进行脱铝改性. 用XRD、氮气吸附-脱附、NH3-TPD、FTIR和NMR等技术进行了表征, 并考察了脱铝前后MCM-49分子筛在苯与丙烯液相烷基化反应中的催化性能. 27Al核磁共振谱表明, 硝酸回流和水蒸气处理能有效地脱除MCM-49分子筛的部分骨架铝和非骨架铝. NH3-TPD和FTIR表征结果表明, 脱铝降低了MCM-49分子筛的Brönsted酸和Lewis酸的酸量. 硝酸脱铝未改变分子筛的酸强度分布, 而在600 ℃水蒸气脱铝则造成酸强度的降低. 实验条件下, MCM-49分子筛的丙烯转化率为99.5%, 异丙苯的选择性为73.6%. 脱铝改性降低了烷基化反应活性和异丙苯的选择性, 提高了收率. 与脱铝前MCM-49分子筛相比, 常温下经硝酸处理5 h的脱铝MCM-49分子筛在保持催化活性相当的情况下, 异丙苯收率提高了5.3%.     

Ligand electronic effects in the palladium catalyzed asymmetric allylic alkylation reaction with planar chiral diphosphine-oxazoline ferrocenyl ligands

A series of planar chiral diphosphine-oxazoline ferrocenyl ligands with different electronic properties were successfully used in the asymmetric allylic substitutent reaction. The enantioselectivity of this reaction was affected by the electronic nature of the ligands. When the electronic effect was coincident with the steric effect of ligand, a higher ee value was observed.     

Synthesis and characterization of α-N,N-dihydroxyethylaminopropyl-ω-butylpolydimethylsiloxanes

A series of α-N,N-dihydroxyethylaminopropyl-ω-butylpolydimethylsiloxanes with different molecular weight were synthe-sized. The preparation included five steps which were hydroxyl protection, alkylation, anionic ring-opening polymerization,hydrosilylation and deprotection. The structure of reaction products was characterized by FF-IR, GC, 1H NMR.     

Stereoselective synthesis of C-tetrasubstituted azabicyclo[X.3.0]alkane amino acids

By a stereoselective alkylation approach a synthesis of eight enantiopure, sterically constrained C^α-tetrasubstituted azabicycloalkane amino acids was carried out.     

Efficient synthesis of alkyl 2,3-unsaturated glucopyranosides from glycals mediated by ytterbium(III) triflate-trialkyl aluminum

Treatment of glycals with trialkylaluminum in the presence of a catalytic amount of Yb(OTf)₃ leads to the corresponding alkyl 2,3-unsaturated glycosides in good to excellent yields. Reactions of protected glycals are achieved under very mild conditions.     

Highly active and stable immobilized aluminium chloride catalyst for alkylation of benzene with 1-dodecene

Summary An AlCl₃ catalyst immobilized on<span lang=EN-US style='font-family:Symbol;mso-bidi-font-family: Symbol;mso-ansi-language:EN-US'>g-Al₂O₃with meso- and macro-pore bimodal structure was prepared and studied in the alkylation of benzene with 1-dodecene in a suspension bed reactor. The catalyst exhibited high activity, selectivity and stability during 1000 h running, with a 1-dodecene conversion of more than 95%, monoalkylbenzene selectivity of 92%, and 2-phenyldodecane (2-Ph) selectivity of nearly 42%.</o:p>