Kinetics of hydroformylation of 1-decene using homogeneous HRh(CO)(PPh3)3 catalyst: a molecular level approach

The kinetics of hydroformylation of 1-decene using homogenous HRh(CO)(PPh₃)₃ catalyst has been reported in the temperature range of 50–70 °C. The effect of catalyst,P _{H 2},P _CO, and 1-decene concentration on the rate of hydroformylation has been studied. Based on the analysis of initial rate data, a rate equation has been proposed and kinetic parameters evaluated. The activation energy was found to be 11.76 kcal/mol. A molecular level approach to kinetic modelling has also been illustrated. The rate equation derived assuming oxidative addition of H₂ as a rate determining step, has been found to represent the data satisfactorily. The rate parameters for the mechanistic model have been evaluated for the data at 60 °C.NCL Communication No. 5735.     

Solubility of gases in a hydroformylation solvent

The solubility of reactants used in homogeneously catalyzed hydroformylation of alkene was studied in a pressurized, semi-batch autoclave. The solubilities of alkene, carbon monoxide and hydrogen in the 2,2,4-trimethyl-1,3-pentanediol mono(2-methylpropanoate) solvent (NX 795) were determined by precise pressure and weight measurements. The measured solubilities were tested against empirical and theoretical models. Logarithmic empirical models gave a very good fit to experimental solubility data. To obtain nonempirical equations for the gas solubility, thermodynamic models based on activity coefficients and equations of state were used. The activity coefficient models based on regular solution theory (RST) predicted the solubilities well, but the selection of the model is the critical issue. For 1-butene, the best prediction was provided by the Yen and McKetta modification of the RST, whereas for carbon monoxide and hydrogen it was necessary to include a mixing entropy term in the RST. The Soave-Redlich-Kwong equation of state gave a fairly good prediction of the solubilities, but not as good as the RST-based models.     

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.     

Intensified hydroformylation as an example for flexible intermediates production

One of the future challenges for chemical engineering is the design of flexible plants allowing an adaptation of production output to market development. Consequently, the target for the design of new processes must be the identification of equipment allowing such an expansion close to market development. To leverage the full benefit of this approach flexibility analysis has to be integrated into process design workflow. In this article the conventional technology for hydroformylation is compared to an intensified process design. This new design consists of a jet loop reactor followed by a membrane section to separate and recycle the homogenous catalyst. In the first part of the article it will be shown that process intensification leads to a net present value improvement of 30% compared to state of the art hydroformylation at a capacity of 100 kt/a. In the second part suitability of the intensified process for a stepwise plant expansion will be demonstrated. In an expansion scenario with two steps equivalent annual annuity is increased by 5% compared to a one step investment.     

Cobalt catalyzed hydroformylation of higher olefins in the presence of chemically modified cyclodextrins

The cobalt catalyzed hydroformylation of higher olefins in the presence of chemically modified cyclodextrins was investigated in an aqueous biphasic system. The effect of various parameters, such as the nature of the cyclodextrin and olefin, the temperature, the CO/H₂ pressure, the concentration of the cyclodextrin and TPPTS was studied. The results demonstrate that the partially methylated β-cyclodextrin gives good conversion (>92%) and selectivity (>92%) for the hydroformylation of higher olefins without impeding the recovery of the catalytic system.     

Indication of water in the coordination sphere of rhodium by conversions of 2,5-dimethoxy-2,5-dihydrofuran with syngas

2,5-Dimethoxy-2,5-dihydrofuran did not form the expected aldehydes when water-soluble rhodium-catalysts were used for the conversion with syngas. Instead of hydroformylation, hydrogenation was the main reaction path in water, where 2,5-dimethoxytetrahydrofuran and its hydrolysis product, succinic dialdehyde, were obtained. The formation of hydrogenation products indicates water in the coordination sphere of rhodium. This may provide us with information on the environment of an active metal in aggregated structures like micelles and vesicles which are gaining in importance in biphasic catalysis.     

Dynamic and kinetic modeling of isotopic transient responses for CO insertion on Rh and Mn–Rh catalysts

Isotopic transient tracer techniques have been employed to study heterogeneous hydroformylation on Rh/SiO₂ and Mn–Rh/SiO₂. Pulse injection of D₂ and allowed tracing of the deuterium and CO incorporation pathway into the aldehyde product. The d₁- and d₂-propionaldehyde responses showed a double-peak, or two-hump, response to the D₂ pulse, while showed a single-hump response to the pulse. Analysis of the product responses to the D₂ pulse in CO/H₂/C₂H₄ and CO/H₂/C₂H₄/C₂H₅CHO suggests that the first hump of the d₁- and d₂-propionaldehyde responses was due to rapid H/D exchange with adsorbed propionaldehyde via enol intermediates. The decay of the second hump was due to reaction of adsorbed acyl with spillover hydrogen/deuterium. The response was due to CO insertion followed by acyl hydrogenation. Compartment modeling of the product responses from the and D₂ pulse inputs allowed determination of residence times of adsorbed intermediates, surface coverages of adsorbed intermediates, and the elementary rate constants for acyl hydrogenation and CO insertion. Elementary rate constants for acyl hydrogenation determined from this study were consistent with the value calculated by transition state theory (TST). The addition of Mn promoter to Rh/SiO₂ increased coverages of , , and and shifted the rate-limiting step for propionaldehyde formation. Acyl hydrogenation is the rate-limiting step on Rh/SiO₂ while CO insertion and acyl hydrogenation are both kinetically significant on Mn–Rh/SiO₂.     

环氧乙烷羰基合成1,3—丙二醇的催化剂配方研究（下）

介绍了环氧乙烷羰基合成１，３－丙二醇过程中的化学特性；考察了不同催化剂组合物配方对反应结果的影响，并对反应产物作了较尽尽的定性分析。     

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.     

磷配体在氨甲酰化反应中的应用

综述了烯烃氧甲酰化反应中所应用的膦和亚磷酸酯两大类配体，其研究经历了单磷、双磷及单磷配体再度兴起的过程。列举了一些有代表性的配体及理论。配体研究的发展过程始终围绕着既能提高催化活性又能提高目的产物区域选择性这个主题。