Aqueous biphasic hydroformylation of olefins: From classical phosphine-containing systems to emerging strategies based on water-soluble nonphosphine ligands

This review provides an overview of recent developments in the area of aqueous biphasic hydroformylation of higher olefins using metal catalysts and surfactants, cosolvents, thermoregulated ligands, cyclodextrins, and most importantly emerging water-soluble nonphosphine ligands. Water-soluble phosphine ligands have been widely explored for aqueous biphasic hydroformylation; however, phosphines are generally expensive and are prone to oxidation hence the recent interest in exploring other ligands. Various approaches have been used to introduce hydrophilicity to the ligands. The catalytic activity of monometallic and heterobimetallic systems containing nonphosphine ligands in aqueous biphasic media is emphasized in this review.     

羰基合成高碳醇工艺研究进展

综述了对液/液两相催化高碳烯烃氢甲酰化制备高碳醇的研究进展,针对经典的水/有机两相体系不能用于催化高碳烯烃氢甲酰化的问题,全面介绍了适用于水/有机两相体系中高碳烯烃氢甲酰化的温控相转移催化法等6种改进方法。同时对氟两相、离子液体两相、超临界流体等非水液/液两相体系中的高碳烯烃氢甲酰化作了系统阐述,并对它们的应用前景进行了评价。     

Rhodium‐catalyzed hydroformylation of unsaturated fatty esters in aqueous media assisted by activated carbon

Concerns about the environmental impact of chemical transformations prompted chemists to develop clean chemical processes using water as a solvent. Although appropriate for small partially water‐soluble molecules, these processes do not allow for the transformation of hydrophobic substrates due to the mass transfer limitation between the aqueous and the organic phase. In this context, we show that activated carbons can be used as mass transfer additives to promote the rhodium‐catalyzed hydroformylation of methyl oleate and other unsaturated olefins. Due to its mesoporous and hydrophobic character, the Nuchar®WV‐B activated carbon proved to be especially effective as mass transfer promoter. Actually, a significant increase in the conversion was observed. Additionally, more than 90% aldehydes were formed during the course of the reaction. When compared to other mass transfer promoters such as co‐solvents or cyclodextrins, Nuchar®WV‐B was by far the most efficient. Thus, the use of activated carbons appeared to be a suitable solution for the aqueous rhodium‐catalyzed hydroformylation of hydrophobic bio‐sourced substrates. Practical applications: The easiness with which the FAME hydroformylation could be implemented in water using activated carbons as mass transfer promoters is a major advantage in a context of an industrial–environmental approach. This finding is of importance as the obtained oxo‐products can be used in many industrial areas such as surfactants, polymers, or lubricants.     

Thermoregulated phase transfer ligands and catalysis. III. Aqueous/organic two-phase hydroformylation of higher olefins by thermoregulated phase-transfer catalysis

A series of poly(ethylene oxide)-substituted triphenylphosphines, Ph_3−mP[C₆H₄-p-(OCH₂CH₂)_nOH]_m (PEO-TPPs; 1a m=1, 1b m=2, 1c m=3; N=m×n=8–25), have been prepared by the ethoxylation of mono-, di-, and tri-p-hydroxytriphenylphosphines. PEO-TPPs demonstrate an inverse temperature-dependent solubility in water, and possess distinct cloud points range from 26°C to 90°C.

Based on the clouding property of PEO-TPPs, a new line of aqueous/organic two-phase catalysis termed the thermoregulated phase-transfer catalysis (TRPTC) has been described. That is, the catalyst transfers into the organic phase to catalyze a reaction at a higher temperature, and returns to the aqueous phase to be separated from the products at a lower temperature. Application of this novel strategy to the rhodium-catalyzed two-phase hydroformylation of higher olefins gave desirable results with an average turnover frequency of 180 h⁻¹ for 1-dodecene. The TRPTC is suitable for carrying out a reaction with extremely water-immiscible substrate in the aqueous/organic two-phase system. Thus, the application scope of the classical two-phase catalysis has been widened.     

镇海炼化PX装置脱烯烃改性催化剂工业应用试验

论述了100t ROC-Z1催化剂在镇海炼化重整装置上取代工业白土的工业试验过程。工业试验结果表明：相对于普通白土颗粒,催化剂ROC-Z1脱烯烃效果优异,使用寿命长,单操作周期内产品质量达标时长为普通白土的3.5倍,反应前后重整油组分中苯、甲苯、C8芳烃、C9芳烃以及非芳烃组分均无明显变化。ROC-Z1催化剂替代白土脱除PX生产原料中烯烃的新技术不但可以促进PX装置本身的清洁生产,而且将有力地减少白土的消耗,减轻对矿产资源的依赖,大幅度地减少废弃物的处置量。在催化剂脱除芳烃中烯烃的机理研究过程中,通过采用色谱-质谱联用的方法,分析了催化剂处理前后原料的变化,研究证实了ROC-Z1催化剂脱除芳烃中烯烃的反应为烷基化反应,遵循正碳离子机理。     

钴的引入对双环戊二烯氢甲酰化担载Rh催化剂的性能影响

以双环戊二烯(DCPD)氢甲酰化反应为探针反应,系统考察了无机氧化物担载的Rh催化剂上引入Co后对性能的影响。实验结果表明:Co的引入不仅可以大幅度的提高DCPD氢甲酰化产物三环癸烷二甲醛(DFTD)的选择性,而且可以加快DFTD的生成速率;相对于Rh催化剂,引入Co之后,DFTD的选择性可以提高20%以上,DFTD的选择性最高可达88.7%。为研究Rh催化剂上引入Co对催化剂活性和目标产物选择性大幅提高的原因,分别对催化剂进行了程序升温还原(TPR)和程序升温脱附(TPD)的表征。TPR的结果显示Co和Rh发生了相互作用,Rh的还原峰明显发生了一定的位移;TPD的结果显示Rh在载体表面的分散性有降低的趋势,表面的Rh活性物种有一定的减少。结合实验数据和表征数据,Rh催化剂上引入Co使催化活性和产物选择性提高的原因可归结为:Co和Rh发生了相互作用;Co的引入虽然造成了表面Rh含量降低,但是形成了高于Rh的活性的新物种,从而导致了催化剂活性和目标产物选择性大幅提高。     

Multifactorial analysis in the study of hydroformylation of oct-1-ene using supported aqueous phase catalysis

The influence of the hydration and the surface characteristics of five supports in the hydroformylation of oct-1-ene by supported aqueous phase catalysis (SAPC) using [Rh₂(μ-S^tBu)₂(CO)₂(TPPTS)₂] as catalyst was studied. The results confirm that the size of the pores and the amounts of water were found to be the determining factors contributing to the SAPC. According to the size of pores there is a critical value for which the SAPC takes place either in the classical model or in conditions where the pores are filled. When the pores are fully filled the SAPC can operate efficiently onto the external surface, stabilising the conversion in a relatively wide range of support hydration.     

Ruthenium carbonyl-complex catalyzed hydroaminomethylation of olefins with carbon dioxide and amines

Use of carbon dioxide as a reactant instead of toxic carbon monoxide in the hydroaminomethylation reaction sequence is demonstrated for the first time. The present Ru₃(CO)₁₂-catalyzed one-pot protocol includes reverse-water–gas-shift (RWGS) reaction, hydroformylation reaction and reductive amination which finally leads to secondary and tertiary amine. The influence of various reaction parameters including the effects of catalytic promotors and phase-transfer-catalysts has been investigated. Finally, an optimum reaction conditions were found by suppressing the major side products to have a variety of amines in excellent yields (up to 98%).     

Chemically modified β-cyclodextrins in biphasic catalysis: a fruitful contribution of the host–guest chemistry to the transition-metal catalyzed reactions

Biphasic hydroformylation, Wacker oxidation and hydrocarboxylation of water insoluble olefins have been investigated in the presence of chemically modified β-cyclodextrins. In all cases, cyclodextrins appear more efficient than common mass transfer promoters to increase the activity and the selectivity of reactions. Most of the results are interpreted from the molecular recognition between the host cavity of modified cyclodextrins and substrate. The stability of the chemically modified cyclodextrins is also reported.     

甲醇制对二甲苯联产低碳烯烃改性ZSM-5催化剂在流化床中的反应性能

在流化床反应器中,对Zn、Si和P改性的ZSM-5催化剂的甲醇制对二甲苯联产低碳烯烃的反应性能进行了研究。采用X射线衍射（XRD）、BET比表面积、扫描电镜（SEM）、NH₃-程序升温脱附（NH₃-TPD）等手段进行表征分析。结果表明,Zn改性使得催化剂酸强度降低,中强酸酸量增加,对二甲苯和低碳烯烃选择性都随之提高;一定量的硅沉积改性在降低催化剂外表面酸量的同时缩小孔口,浸渍适量P能够调变分子筛的酸中心强度和酸量,这都能够提高对二甲苯选择性。在流化床反应器中甲醇制对二甲苯联产低碳烯烃反应结果表明,3Zn-3Si-3P/ZSM-5催化剂在温度425℃、常压、反应时间40min、空速1h^-1的条件下,对二甲苯在二甲苯中的选择性为76.0%,C₂~C₄低碳烯烃选择性为24.4%,特别是芳烃和C₂~C₄低碳烯烃的总选择性高达92.2%。     

Catalytic asymmetric hydroformylation in the presence of compressed carbon dioxide

The asymmetric hydroformylation of styrene using [(CO)₂Rh(acac)]/(R,S)‐BINAPHOS as catalyst precursor occurs smoothly in the presence of compressed CO₂ to give appreciable asymmetric induction (ee = 66% (R)) under conditions close to the critical data of pure CO₂, but very low ees are obtained at high CO₂ densities. The phase behaviour of the reaction medium and the different solubilities of the unmodified and ligand‐modified catalytically active species in the supercritical phase provide a possible rationalisation of the results. This revised version was published online in July 2006 with corrections to the Cover Date.     

Unexpected products of the allyldiethylamine hydroformylation homogeneously catalyzed by rhodium complexes

Attempts to carry out the hydroformylation of allyldiethylamine homogeneously catalyzed by rhodium complexes led to unexpected formation of N,N,N,N-tetraethyl-1,4-diaminobutane and 4-(diethylamino)-1-butanole as final products. The role of the catalyst on the product formation and the reaction mechanism are briefly discussed.     

Electrochemical homolytic and heterolytic coupling of activated olefins in the absence and presence of benzyl bromide in microemulsion

Electrochemical reduction of four activated olefins namely cyclohexenone (CH), cyclopentenone (CP), methylmethacrylate (MMA), acrylonitrile (AN) in the absence and presence of benzylbromide (BBr) were investigated in CTAB/n-hexane/n-butanol/water based bicontinuous microemulsion (μE). Both cyclic voltammetric studies and galvanostatic preparative electrolysis were carried out. Cyclic voltammetric results in μE were also compared with those in N,N-dimehtylformamide (DMF) medium. Adsorption effects are observed both in DMF and μE. AN undergoes one electron reduction in aprotic solvent and two electron reduction in μE. CH, CP, BBr undergo one electron reduction and yield significant homolytic coupled products under galvanostatic conditions. AN and MMA lead to two electron reduction under identical conditions. In the presence of BBr, CH and CP alone yield significant heterolytic coupled products with simultaneous competitive resin formation. Reduction of AN leads to the formation of a identifiable quantity of propylamine and 3-phenylpropylamine in the absence and in the presence of BBr, respectively.     

Studies based on the electrochemical response of 2-(2-nitrophenyl)-1H-benzimidazole at chemically modified electrodes with over-oxidized poly-1-naphthylamine

The development of a simple and efficient method to 2-(2-nitrophenyl)-1H-benzimidazole (NB) electrochemical determination using a polymer film coated chemically modified electrode is described. A glassy carbon (GC) electrode was modified employing an electro-polymerized film of 1-naphtylamine (1-NAP) followed by an over-oxidation treatment in 0.2 M sodium hydroxide solution (poly-1-NAPox electrode).The electrochemical behaviour of NB at the poly-1-NAPox electrode was investigated in a mixture of 10% ethanol + 90% buffer solution (pH 2) by cyclic voltammetry (CV) and square-wave voltammetry (SWV). The experimental results suggested that the poly-1-NAPox electrode had a good effect on NB electrochemical response because it avoided the electrode surface fouling as a consequence of the adsorption of NB reduction products, which was found when a bare GC electrode was employed as the working electrode. The NB cathodic current was dependent on the polymeric film over-oxidation degree (α).NB could be determined in the range from 2 × 10⁻⁶ to 5 × 10⁻⁵ M. The NB detection and quantification limits were 5 × 10⁻⁷ and 1.7 × 10⁻⁶ M, respectively. The percent relative standard deviation of the peak current to 10-replicated measurement using 1.2 × 10⁻⁵ M NB solution was 1.4%. The method showed to be rapid, simple and with a good sensitivity.     

硫酸高铈改性离子交换树脂催化合成尼泊金丁酯

首次采用硫酸高铈与阳离子交换树脂反应制备的改性离子交换树脂为催化剂合成尼泊金丁酯。考察了催化剂用量、醇酸物质的量比、反应时间及带水剂等因素对收率的影响。结果表明,该催化剂具有催化活性高、后处理方便,废液排放量少等优势。最佳反应条件为:醇酸物质的量比3,催化剂0.5 g,反应时间5 h,收率达93.1%。     

Adsorbed carbocations as transition states in heterogeneous acid catalyzed transformations of hydrocarbons

Ab initio quantum chemical calculations indicated that adsorbed carbenium and carbonium ion active intermediates of acid-catalyzed transformations of hydrocarbons on zeolites are not the really existing highly reactive species but the transition states of the corresponding elementary steps. Adsorbed carbenium ion-like activated complexes can be formed both via proton addition to the double bonds of olefins or as energetically excited unstable ion pairs resulting from partial dissociation of the carbonyl bonds in more stable alkoxy species. In contrast, the highly energetically excited adsorbed carbonium ion-like transition states result only from proton attack at the C–C or C–H bonds of paraffins. The quantum chemical calculations provided the information on geometry and electronic structure of these activated complexes which depend on the elementary reactions in which these transition states are involved. The calculated heat effects and activation energies for the main elementary steps in acid catalyzed transformations of hydrocarbons on zeolites, i.e. of double bond shift, skeletal isomerization and cracking of olefins or protolytic dehydrogenation, protolytic cracking of paraffins and hydride transfer from isoparaffins to carbenium ions are in a reasonable agreement with the experiment.     

Esterification of ethenyl benzene and its derivatives with acetic acid in the presence of perchloric acid as a catalyst

The esterification process of ethenyl benzene and its derivative compounds (p-methyl, p-methoxy, p-chloro, m-methyl, m-nitro and m-chloro, respectively) was carried out with acetic acid and using perchloric acid as a catalyst. From the effects of the variables studied it could be concluded that: the temperature and the catalyst concentration influence positively over the olefin conversion, whereas the initial olefin concentration exert no effect over the same; and that the presence of perchloric salts exerts a different influence, depending on the temperature and on the catalyst concentration. It has been proven that the substituted radicals in the m- or p- positions exert an important influence over the conversion of the studied olefins, presenting growing reactivity in the following order: m-nitro ethenyl benzene, m-chloro ethenyl benzene, p-chloro ethenyl benzene, m-methyl ethenyl benzene, ethenyl benzene, p-methyl ethenyl benzene and p-methoxy ethenyl benzene. Finally, a kinetic and thermodynamic study has been done and the corresponding parameters have been calculated, with an adequate fitting.     

Effect of temperature on Co electrodeposition in the presence of boric acid

The electrodeposition of cobalt from sulphate solutions containing boric acid was investigated using EQCM technique coupled with potentiostatic measurements. The boric acid was added to electrolyte as a buffer to avoid the local pH rise caused by parallel hydrogen evolution reaction (HER). The results showed that the buffer contribution of boric acid is effective in the cobalt electrodeposition at 25 °C; however, cobalt hydroxide is formed simultaneously with cobalt deposition at 48 °C. The M/z values calculated using the Sauerbrey equation and the Faraday Law showed that in the initial stages of deposition at 48 °C, only cobalt deposits were detected, but after 2 s, an important amount of Co(OH)₂ started to be formed.     

CoTPP-TBAB catalyzed tandem transformation of styrene carbonate from styrene in the presence of O2 and CO2

The direct synthesis cyclic carbonate from styrene, O₂ and CO₂ is of great academic attraction and industrial value in modern chemistry. The metalloporphyrin/tetrabutylammonium bromide was employed as binary catalyst for this reaction in the presence of O₂ and CO₂ by using methyl 2-cyclopentanone-carboxylate as co-catalysts. The effects of reaction parameters on catalytic performance were investigated systematically. Under the optimal reaction conditions, conversion of styrene (99%) and selectivity to cyclic carbonate (35%) were obtained. The possible mechanism of cascade reaction was proposed by using in-situ ultraviolet and infrared spectroscopy. The results show that the cobalt center is coordinated with the ring oxygen atom of methyl 2-oxocyclopentanecarboxylate to activate oxygen to form a peroxy active species, thereby forming a high-valent cobalt-oxygen intermediate, which passes oxygen atoms to styrene and generate epoxy styrene. Then, styrene oxide opened ring under the catalysis of tetrabutylammonium bromide, and finally formed cyclic carbonate through CO₂ insertion reaction and intramolecular ring-closing reaction.     

钴卟啉-四丁基溴化铵串联催化苯乙烯在氧气和二氧化碳中合成碳酸苯乙烯酯

通过仿生催化,将苯乙烯、氧气(O₂)和二氧化碳(CO₂)直接合成环状碳酸酯在现代化学中极具学术研究意义和工业应用价值。采用钴卟啉-四丁基溴化铵为双组分催化剂,以2-氧代环戊烷羧酸甲酯为助剂,在O₂和CO₂条件下,直接将苯乙烯转化为碳酸苯乙烯酯。系统考察了催化剂用量等因素对催化性能的影响。在最佳反应条件下,苯乙烯的转化率高达99%,环状碳酸酯的收率可达35%。利用在线紫外与在线红外探讨了该串联反应可能的机理。结果表明,钴中心与2-氧代环戊烷羧酸甲酯的环内氧原子配位后活化氧气形成过氧活性物种,进而形成高价钴-氧中间体,其通过传递氧原子给苯乙烯而生成环氧苯乙烷。而后,环氧苯乙烷在四丁基溴化铵的催化作用下开环,并通过CO₂插入反应和分子内闭环反应最终生成环状碳酸酯。