双亚磷酸酯和双膦组合配体在丁烯氢甲酰化反应中的应用研究

考察了双亚磷酸酯配体Biphephos及双膦配体DPPE、DPPP、DPPB、BISBI在丁烯氢甲酰化反应中的反应活性和选择性,并对双亚磷酸酯配体和双膦配体进行组合,应用到丁烯氢甲酰化反应当中,对组合配体进行筛选发现Biphephos与DPPB组合配体的反应效果最佳,明显提高了产物醛的正异构比。通过正交实验进一步优选了铑催化剂浓度、Biphephos浓度与DPPB浓度,其优化的催化剂配方的正异构比达到76.3,平均TOF1821h-1。     

Application of transition metals in hydroformylation annual survey covering the year 2001

Hydroformylation in homogeneous and heterogeneous systems, and hydroformylation related reactions of carbon monoxide reported in 2001 are reviewed.     

Monomeric ruthenium carbonyls containing 2-substituted pyrazines: From synthesis to catalytic activity in 1-hexene hydroformylation

Synthesis and catalytic properties of a series of ruthenium carbonyl complexes with 2-substituted pyrazine ligands (pz–R; R = Cl, OMe, SMe, CN, NH₂) have been studied. Reactions between the [Ru(CO)₃Cl₂]₂ and the pyrazines led mainly to mononuclear compounds of the type [Ru(CO)₃Cl₂(R–pz)]. All of these ruthenium pyrazine compounds showed activity in 1-hexene hydroformylation. With an exception of NH₂, addition of the substituent to the pyrazine ring was found to improve the catalytic activity compared to the unsubstituted pyrazine. The catalytic cycle was studied by computational DFT methods. The results suggest that the key step in the formation of the active species involves release of one of the carbonyl in the cis position with respect to the pyrazine ring.     

温控相分离催化的高碳烯烃氢甲酰化反应研究

考察了非离子表面活性膦配体P[p-C6H4O(CH2CH2O)nH]3(PETPP,n=6～12,N=3n)在有机溶剂中的溶解度－温度关系，发现其在甲苯中具有临界溶解温度（CST）现象。基于PETPP在甲苯中低温分相、高温互溶的CST特性，提出了温控相分离催化的新概念。并将其应用于癸烯氢甲酰化反应，转化率及醛收率分别达到98.7%和96.0%，催化剂循环使用10次，活性基本保持不变。     

膦配体链长对锚合膦配体修饰的Rh/SiO_2催化剂上氢甲酰化反应性能的影响(英文)

烯烃氢甲酰化反应产物醛是生产多种有机化合物的重要中间体,具有重要的工业价值.均相催化剂具有反应条件温和及催化效率高的优点,因而成为工业应用的主要催化体系,但催化剂分离复杂且昂贵.多相催化剂具有易分离和易回收的优点,但在氢甲酰化反应中的活性和选择性较低,因而大大阻碍了其在工业上的应用.为了得到兼具两种催化剂优点的新型催化剂,人们进行了数十年的研究,均相催化剂多相化便是其中一个研究热点.实现该策略最常用的一个方法是将均相催化剂固载到载体上,以此来达到催化剂易从反应物及产物中分离,同时保有高活性高选择性的目的.通过化学键将金属配合物的配体键合到载体上已经取得了一定的成功,但依然存在着活性组分流失和催化剂失活的问题.本课题组开发了一种锚合膦配体修饰的Rh/SiO_2新型催化剂,在乙烯氢甲酰化反应中表现出卓越的稳定性,反应1000 h后依然没有出现活性下降和组分流失的现象,这是因为配体和活性金属同时被固载在载体SiO_2上.但是由于配体和活性金属都不能自由移动,很多配体不能与金属原子有效接触,起不到配位效应,因而催化剂活性仍不够高.因此,为了提高锚合膦配体修饰的Rh/SiO_2催化剂的活性,我们合成了具有较长链长的膦DPPPTS,并与商业购买的链长较短的膦DPPETS做对比,研究锚合膦配体链长和催化剂活性的关系.使用N_2物理吸附、原位红外光谱(FT-IR)和固体~(31)P核磁共振(NMR)等探讨了膦配体链长影响催化性能的原因.固定床上乙烯氢甲酰化反应结果表明,当膦配体的链长增长一个亚甲基长度后,反应稳定后催化剂的活性提高了一倍以上.N_2物理吸附实验表明,延长配体的链长对催化剂结构性质的影响不大,因而也不会改变反应时的传质.催化剂吸附合成气(CO:H_2=1:1)的原位FT-IR结果表明,不同链长膦配体修饰的Rh/SiO_2催化剂上均原位生成了类似于用于均相氢甲酰化反应的Wilkinson型催化剂的活性物种HRh(CO)_2(DPPPTS)_2[或HRh(CO)_2(DPPETS)_2],以及吸附在Rh上的线式CO.这两种吸附物种均利于氢甲酰化反应的进行,其中以前者活性更好.从原位FT-IR结果同样看出,锚合链长较长的膦配体的催化剂(DPPPTS-Rh/SiO_2)上原位生成的活性物种量更多,因而催化活性更高.固体~(31)P NMR结果表明,催化剂上的膦以自由态的膦(高场峰β)和与Rh配位的膦(低场峰α)两种形式存在.α峰面积和β峰面积之比(r)越高代表与Rh配位的膦配体占总膦量的比例越高.发现DPPPTS-Rh/SiO_2催化剂的r值(1.31)高于DPPETS-Rh/SiO_2催化剂(1.05),即前者与Rh配位生成活性物种的膦配体的比例更高.结合原位FT-IR和固体~(31)P NMR的结果可知,链长较长的DPPPTS更容易与Rh配位,从而生成更多的铑膦配合物活性物种,因而催化剂活性更高.因此,增长锚合膦配体的链长有助于提高其修饰的Rh/SiO_2催化剂的活性.     

Carbon monoxide as a reagent: A report on the role of N-heterocyclic carbene (NHC) ligands in metal-catalyzed carbonylation reactions

This report is a focused and critical essay on the effectiveness of M–NHC catalysts in reactions that specifically utilize carbon monoxide as a C1-carbon source. NHC ligands are touted as excellent trialkylphosphine (PR₃) mimics and are purported to improve existing phosphine based catalysts. One premise for using NHCs is that the need for excess ligand could be obviated in certain reactions. If true, then reactions involving CO as a reagent should be improved when a M–NHC complex is employed. Herein is a compilation of results that feature CO as a reagent in reactions such as: hydroformylation, hydroaminomethylation, carbonylation of aryl halides, oxidative carbonylation of amino and phenolic compounds, and the copolymerization of alkenes and CO. The aim of the report is to highlight reactions in which the ancillary NHC ligand is beneficial, detrimental, ineffective, or inconclusive in promoting the desired chemistry.     

Fine tuning of sulfoalkylated cyclodextrin structures to improve their mass-transfer properties in an aqueous biphasic hydroformylation reaction

The structure of sulfoalkylated cyclodextrins (CDs) have been varied and optimised to improve their performances as mass-transfer promoters in an aqueous biphasic hydroformylation reaction. Their surface tensions have been measured using the Wilhelmy plate technique and compared. Their behaviour towards two hydrosoluble derivatives of triphenylphosphine has been evaluated by ³¹P{¹H} and ¹H NMR measurements and their catalytic activity has been assessed in a rhodium-catalyzed hydroformylation reaction of 1-decene. The best result was obtained using a β-CD sulfobutylated on the primary face and methylated on the secondary face. Indeed, this CD increased the reaction rate by a factor of 250 without inducing selectivity decrease. The accessibility to the secondary face of the CD appears to be determining in the catalytic process as it governs the approach between the CD-included substrate and the water-soluble catalyst. The impact of the nature of the CD substituents on the chemo- and regioselectivity of the reaction is also discussed.     

Rhodium catalysed hydroformylation of unsaturated esters

Rhodium catalysed hydroformylation of unsaturated esters has been studied. A pronounced temperature dependence was observed on the regioselectivity and catalytic activity for these reactions, and under the appropriate conditions, it is possible to obtain preferentially either linear or quaternary products. A quaternary selective hydroformylation of methyl atropate to give 1,3-aldehydic esters has also been developed.     

Rh—Y分子筛上乙烯氢甲酰化反应的研究

常压下乙烯在Rh-Y分子筛催化剂上的氢甲酰化反应存在一定的诱导期。在反应条件下,加氢反应和氢甲酰化反应同时进行。在反应初期,含氧化合物活性的增加伴随着乙烷活性的降低,反应达到平衡的时间取决于对催化剂的预处理条件,反应前后,催化剂的颜色有明显变化(淡黄色变成红棕色):根据XPS的研究结果,新鲜催化剂与用过催化剂的Rh_3d5/2结合能为309.1和306.9eV,分别对应于铑的三价态和零价态。这预示着金属态的铑粒子可能是乙烯氢甲酰化反应的活性中心或它的前身。另外,反应条件下的红外光谱清楚地表明,催化剂的H_2还原处理在活性中心的形成过程中起着非常重要的作用。     

担载金属簇的研究——Ⅵ.担载Ti—Co羰基金属簇的合成和加压原位红外光谱

将双(环戊二烯基)二氯化钛(Cp_2TiCl_2)负载到聚苯乙烯载体上,再与Co_2(CO)_8反应,合成了三种担载的准异核羰基金属簇p(?)CH_2 Cp_2Ti(Cl)OCCo_3(CO)_9。用IR表征结构并研究担载金属簇的热稳定性、乙烯氢甲酰化反应的催化性能及反应机理。