Increasing selectivity of the hydroformylation in a miniplant: Catalyst,solvent, and olefin recycle in two loops

The application of thermomorphic solvent systems offers the combination of homogeneous catalysis in a single phase and catalyst recovery via phase separation. To increase economic feasibility the minimization of waste streams and side reactions is desired. For this, a continuous process for the hydroformylation of 1‐dodecene in the solvent system DMF/n‐decane is shown. While the Rh/Biphephos catalyst is recycled in DMF in a first loop, the n‐decane and remaining olefins are separated from the product via distillation to form the second loop. In this process the need for additional solvent supply and the isomerization reaction of 1‐dodecene is reduced significantly. The reaction toward internal olefins decreases from initially 15 to 3%. The stable hydroformylation process with a yield of the linear hydroformylation product of 55% and l/b‐ratio of 95/5 is shown for 120 h. © 2016 American Institute of Chemical Engineers AIChE J, 62: 4377–4383, 2016     

Hydroformylierung mit wasser- und methanollöslichen Rhodiumcarbonyl/Phenyl-sulfonatoalkylphosphan-Katalysatorsystemen – Ein neues Konzept für die Hydroformylierung höhermolekularer Olefine

Hydroformylation with Water- and Methanol-soluble Rhodium Carbonyl/phenyl-sulfonatoalkyl-phosphine Catalyst Systems – A New Concept for the Hydroformylation of Higher Molecular Olefins The heterogenization of the homogeneous hydroformylating catalyst system enables the recovery of the catalyst from the reaction products by a simple phase separation but it is unfavourable that many advantages of the homogeneous catalysis are given up by this procedure. To avoid this drawback we used rhodium carbonyl/tert. phosphine catalyst systems soluble as good in methanol as in water for the homogeneously catalyzed hydroformylation of the olefin in methanolic solution. Only after reaction the product mixture is heterogenized by adding water forming an aqueous phase containing the catalyst system. It was shown by the hydroformylation of n-tetradecene-1 with rhodium carbonyl/phenyl-sulfonatoalkyl-phosphine catalyst systems that this new conception is very useful for the oxo reaction of high-molecular olefins.     

Biphasic and Flow Systems Involving Water or Supercritical Fluids

Two processes are described for improving reaction rates for relatively hydrophobic substrates in aqueous biphasic systems. In the first, 1-octyl-3-methylimidazolium bromide ([Octmim]Br) increases the rate of hydroformylation of 1-octene from 8% conversion in 24 h to full conversion of 1.5 h. Phase separation is fast and catalyst retention is good. 1-Hexyl-3-methylimidazolium bromide gives little rate enhancement, whilst 1-decyl-3-methylimidazolium bromide gives stable emulsions., The mechanism of action of these additives is discussed. In the second approach, functionalising PPh₃ with amidine groups allows the rhodium catalysed hydroformylation of 1-octene in toluene with a very high reaction rate. The catalyst can be switched between toluene and water by bubbling CO₂ and back into toluene by bubbling N₂ at 60 °C. This switching has been used to separate the catalyst from hydrophobic (from 1-octene) or hydrophilic (from allyl alcohol) aldehydes obtained from hydroformylation reactions. CO₂ expanded liquids have been shown to be effective media for transporting substrates and catalysts over supported ionic liquid phase (SILP) catalysts. The advantages offered over all gas phase and liquid phase catalysts are discussed.     

Supramolecular transition metal catalysts in two-phase systems

The concept of covalently connecting a catalytically active transition metal center with a water-soluble receptor (host molecule) makes a new type of supramolecular catalysis possible in which the features of molecular recognition, phase transfer catalysis and transition metal catalysis are combined in a single system. The first examples of this principle make use of the commercially available β-cyclodextrin (β-CD) as the receptor and rhodium complexes of diphosphanes as the catalytically active center, these being covalently connected to one another via a spacer. In competitive hydrogenation of certain olefins unusual degrees of substrate selectivity based on the molecular recognition are observed, not possible by conventional transition metal catalysts. The two-phase (H₂O/organic) hydrogenation of nitro-aromatics also is a smooth process with these supramolecular catalysts. They also constitute an unusually active catalyst system for the selective hydroformylation of higher olefins such as 1-octene in a two-phase system.     

Improving Aqueous Biphasic Hydroformylation of Unsaturated Oleochemicals Using a Jet‐Loop‐Reactor

In two case studies, the reaction performance of the aqueous biphasic hydroformylation of two industrially relevant oleochemicals, namely methyl 10‐undecenoate (case 1) and methyl oleate (case 2), is significantly improved by the use of a Jet‐Loop Reactor concept. Based on previously reported studies, only the two green and benign co‐solvents, 1‐butanol and isopropanol are applied, respectively, in the absence of any additional auxiliary. Both reactions benefit highly from using this special piece of equipment, specifically designed for improving gas–liquid–liquid mixing to create large interfacial areas with no moving internals. In case 1, the loading of the co‐solvent 1‐butanol is successfully reduced. For the first time significant yields (>40% after 1 h) are obtained in the absence of any co‐solvent, which is very beneficial, since aldehyde products and substrate form a pure product phase enabling straightforward separation. In case 2, the loading of the substrate methyl oleate is successfully increased from 6 to 30 wt% still showing satisfying productivity. At 15 wt%, the yield of the desired internal aldehydes in the jet‐loop reactor is increased by a factor of five compared to a stirred tank reactor after 3 h. Practical Applications: The production of aldehydes from hydroformylation of olefins is highly relevant for the chemical industry, since these can undergo numerous subsequent reactions, to form for instance alcohols, amines, and carboxylic acids. Generally, aldehydes from oleochemicals can serve as platform chemicals for gaining access to bifunctional molecules, which are interesting as polymer precursors. Performing hydroformylation with a water‐based solvent system enables efficient product separation from the aqueous catalyst phase for the realzation of more sustainable processes. By using the Jet‐Loop Reactor, the performance of the reaction system can be greatly improved addressing its practical relevance.     

CATALYST PRODUCT SEPARATION TECHNIQUES IN HECK REACTION

The Heck reaction finds several applications in industry because it is one of the effective tools for the formation of a new C─C bond. In addition to the catalytic activity and selectivity, catalyst-product separation strategies are very important for the industrial application. There are various methods of interest ranging from conventional heterogeneous catalysts to heterogenization of homogeneous catalysts. The heterogeneous catalysts are classified into supported metal catalysts, zeolite-encapsulated catalysts, colloids-nanoparticles, and intercalated metal compounds. The homogeneous metal complexes catalysts are heterogenized using modified silica catalysts, polymer-supported catalysts, biphasic catalysts, supported liquid-phase catalysts, nonionic liquids solvents, perfluorinated solvents, and reusable homogeneous complexes. In general, heterogeneous catalysts are effective and stable at higher temperatures, which may be important for the activation of less reactive but less expensive chloroaryls substrates. However, the heterogeneous catalysts have a major drawback of poor selectivity toward Heck coupling products. The heterogenized metal complexes catalysts operate under relatively mild conditions as compared with heterogeneous catalysts, and so they can be applied to the production of pharmaceuticals and fine chemicals. Catalysis using supercritical solvents with catalyst separation techniques is promising for the development of green chemistry processes. Although the concepts described in this article have been reviewed mainly for Heck reactions, they should be applicable to a wide range of other chemical transformations (hydrogenation, carbonylation, hydroformylation, and so on) that, currently, are homogeneously catalyzed reactions.     

Hydroformylation of olefins by Au/Co3O4 catalysts

The hydroformylation of olefins over supported gold catalysts in an autoclave reactor under mild conditions (100–140 °C, 3–5 MPa) has been studied. Over Au/AC (activated carbon), Au/PVP (polyvinylpyrrolidone), Au/Al₂O₃, Au/TiO₂, Au/Fe₂O₃, Au/ZnO, Au/CeO₂ and Co₃O₄, 1-olefin mainly remained unchanged and the major products were isomerized olefins or hydrogenated paraffin. In contrast, Au nanoparticles deposited on Co₃O₄ led to remarkably high catalytic activities in hydroformylation reaction with selectivities above 85% to desired aldehydes. The hydroformylation of olefins proceeds preferentially at temperatures below 140 °C, above which the reactions of olefins gradually shifted to isomerization and then to hydrogenation. It appeared that the activity and selectivity of hydroformylation reaction strongly depend on the molecular structure of olefins, which could be ascribed to steric constraints as internal olefins are relatively inappropriate to form alkyl group and subsequent acyl group by insertion of CO. The Au/Co₃O₄ catalyst can be recycled by simple decantation with slight decrease in catalytic activity along with an increase in recycle times, which is a great advantage over homogeneous catalysts. The role of gold nanoparticles can be assumed to dissociate hydrogen molecule into atomic species which reduce Co₃O₄ to Co metal under mild reaction conditions.     

Verlustfreie Katalysatorrezirkulation durch ein neuartiges Verfahrensprinzip bei der Hydroformylierung höhermolekularer Olefine

Free-of-loss Catalyst Recycling in the Hydroformylation of Higher Molecular Olefins by a Novel Process Technology In this paper a novel homogenous-heterogeneous procedure for the hydroformylation reaction of higher molecular olefins is presented, at which the reaction itself is homogeneously catalyzed and only after the reaction the catalyst complex is heterogenized only for separation. This procedure is achieved by using the lithium salt of triphenylphosphine monosulfonic acid (Li-TPPMS) as complex ligand for the hydroformylation catalyst and methanol as solubilizer. Li-TPPMS and its complexes with metal carbonyls are highly soluble in water and methanol, but completely insoluble in almost all other organic solvents. After the reaction the methanol is distilled off. The catalyst system becomes insoluble and can be separated from the reaction product by filtration or by extraction with water. The aqueous catalyst solution is evaporated to dryness and the catalyst system dissolved in methanol for a new reaction.     

Hydroformylation of C8 olefins catalyzed by rhodium–inorganic ammonium salt systems

The effect of inorganic ammonium salts which contain group VIB metals of the periodic table (ammonium chromate, ammonium dichromate, ammonium molybdate and ammonium tungstate) as additives on the catalytic performance of Rh catalysts for the hydroformylation of C₈-olefins and 1-dodecylene has been investigated. Modification of rhodium with ammonium salts could increase the yield of aldehydes in the hydroformylation of the olefins without phosphine oxide or phosphine ligands and also decrease Rh loss in the distillation process for the separation of the products from the catalyst.     

Katalysatorrecycling in der homogenkatalysierten Kreuzmetathese von Ölsäuremethylester und 4‐Octen

The recycling of homogeneous metathesis catalysts is a big challenge in alkene metathesis. Within this contribution the recycling of these catalysts is investigated in the cross metathesis of methyl oleate and 4‐octene as model reaction. Fluid‐fluid separation technique and temperature dependent solvent systems allow the separation of the homogeneously solved catalysts from the metathesis products. The catalyst phase was successfully recycled in multiple recycling runs only with minor loss of yield.     

Zweiphasen-Hydroformylierung höhermolekularer Olefine mit ethoxyliertem Tris-(p-hydroxyphenyl)phosphan als Komplexligand für den Rhodiumcarbonyl-Katalysator

Two-phase Hydroformylation of Higher Molecular Olefins by Ethoxylated Tris(p-hydroxyphenyl)-phosphine as Complex Ligand for the Rhodiumcarbonyl Catalyst Water-soluble rhodiumcarbonyl complexes with new nonionic complex ligands prepared by ethoxylation of tris(p-hydroxyphenyl)phosphine were successfully used in the two-phase hydroformylation of higher-molecular olefins. Their efficiency depends likely on a temperature controlled circulation of the catalyst complex between the organic and the water phase: At the temperature of the hydroformylation (100–130 °C) the ethoxylated tri-(p-hydroxyphenyl)phosphine becomes water-insoluble (appearance of a miscibility gap) and is now available for the catalysis in the organic phase. After cooling to room temperature the catalyst system is dissolved again in the water phase and can be recovered by a simple phase separation.     

Mixtures of Ionic Liquids and Water as a Medium for Efficient Enantioselective Hydrogenation and Catalyst Recycling

In a screening of ligands, ionic liquids and reaction conditions in the Rh‐catalyzed hydrogenation of enamides, a novel multi‐phase reaction system consisting of an ionic liquid (IL) and water (wet ILs) was found to give the most promising results. In many cases such IL/water combinations were superior compared to conventional organic solvents and biphasic ILs/organic co‐solvents media with respect to catalytic performance as well as to catalyst separation and recycling. So far, the best results were obtained with Rh‐ferrocenyl‐diphosphine catalysts (>99% ee). Generally, somewhat lower ees were observed at higher pressure. However, this effect was less pronounced with wet ILs than with conventional solvents. It is shown that IL/water combination allow repeated catalyst recycling without significant loss of activity and that industrially relevant turnover numbers of >10,000 can be obtained.     

国外工业氢甲酰化的现状和发展

自 60年前羰基合成 (OXO)技术发现以来 ,形成了非常大的对醛的需求 ,如今已生产出C2～ 1 8链长的醛。其中丙烯转化成丁醇起着最重要的作用。由于产能过剩和替代产品的加入 ,所以这一市场的竞争非常激烈。最具活性的催化剂体系是以含膦配体改性的Rh络合物。人们已经进行各种研究以利用这些体系 ,已经建立起生产NBA、转化长链烯烃的工业工艺体系。随着越来越少的公司生产大部分产品 ,工业研究正在日益集中。工业研究的焦点是催化剂的开发和研制 ,目前在研究领域越来越关注两相反应的开发     

甲醛和丙醛Mannich缩合制备甲基丙烯醛

甲基丙烯醛（MAL）作为一种重要的有机合成中间体，在医药农药、香精香料、工业助剂、水泥减水剂等领域应用非常广泛。甲醛和丙醛Mannich缩合法合成MAL具有反应条件温和、操作简单、副产物少等优点。本文概述了MAL的工业应用、Mannich缩合反应机理，着重阐述了甲醛和丙醛的Mannich缩合催化剂及反应工艺的研究进展。文中指出，目前Mannich缩合制MAL采用的均相催化体系及工艺，催化剂用量大且难以分离和循环利用，环境污染严重，成本较高；多相催化体系的应用解决了催化剂的分离和重复利用问题，但目前催化剂活性和选择性较低。因此，未来的研究应该重点关注：①开发高效的新型均相催化剂以及相应的连续反应工艺，降低催化剂用量；②开发高性能的多相催化剂，提高催化剂的活性和选择性。     

Thermoregulated phase-transfer cobalt catalyst for production of linear higher alcohols from C11–12 internal olefins in aqueous/organic biphasic system

The thermoregulated phase-transfer cobalt catalyst, composed of a polyethylene glycol tailed phosphine ligand and cobalt carbonyl, has been applied for the conversion of normal C_11–12 internal olefins into linear higher alcohols via hydroformylation and hydrogenation in an aqueous/organic biphasic system. Good catalyst activity (TOF = 2.2 h^− 1) in this biphasic system was obtained which was as high as that in the homogeneous system where a cobalt catalyst was modified by a lipophilic phosphine ligand. Easy catalyst recovery has been done by phase decanting, and the aqueous phase with the cobalt catalyst was used directly in recycling. In 4 times of recycling tests, the yield of alcohols decreased slightly, the leaching of cobalt into the organic phase was less than 2.7% each time and a total catalyst TON of around 150 was obtained.     

Reverse flow adsorption: integrating the recovery and recycling of homogeneous catalysts

Homogeneous catalysts are not applied often when compared to the use of heterogeneous catalysis due to various drawbacks of the usual recovery methods. In this paper, a novel concept is proposed for the integrated recovery and recycling of homogeneous catalysts. It combines an adsorptive separation with the reverse flow technology: reverse flow adsorption. Na⁺ loaded Amberlyst 15 proved to be one of several suitable adsorbents for the reversible adsorption of homogeneous catalysts. A simplified plug flow model for packed beds showed that the implementation of the reverse flow adsorption concept into an oxo-synthesis process would only require two adsorption beds with a very small relative volume of only 1% compared to the volume of liquid reaction phase in the reactor. The adsorption temperature, which was chosen to be equal to the reaction temperature, was well within the stability constraints of the homogeneous catalyst and therefore, decomposition of the catalyst is not expected. Reverse flow adsorption is a promising concept that overcomes the drawbacks of the standard recovery methods and therefore, has a high potential to succeed.     

Hydroformylation of olefins using dispersed molecular catalysts on solid supports

A new method for heterogenization of metal complex catalysts by precipitation of its water–soluble analogue as a Gr.2 metals (Ca, Sr or Ba) salt on porous supports has been proposed. This technique yields a highly dispersed catalyst having a significantly higher activity (TOF) for hydroformylation of olefins compared to other known heterogenized catalysts. The catalyst can be recycled with ease.     

A novel approach to selecting thermomorphic multicomponent solvent systems (TMS) for hydroaminomethylation reactions

In industrial practice, several important examples of homogeneously catalyzed reactions using biphasic catalysis can be found. Using a transition metal catalyst soluble in another phase than the one containing the starting compounds and the products allow for simple separation and recycling of the usually expensive catalysts, but at the same time may cause severe problems with mass transfer. Thermomorphic multicomponent solvent (TMS) systems provide an elegant means to avoid this difficulty and take a big step toward the intensification of the process. One way to use these systems is the application of solvents that are not part of the reaction mixture. However, to reach higher space–time yields, it is also possible to integrate parts of the reaction mixture into the TMS system. The present work aimed to systematically analyze the available solvents for use in an integrated TMS system for the hydroaminomethylation of 1-octene with morpholine, and to develop criteria for the systematic search for applicable solvents in order to minimize catalyst leaching. Several solvents selected by rigorous application of these criteria were then tested in the reaction under biphasic and thermomorphic conditions.     

Metal-organic cooperative catalysis in C-H and C-C bond activation and its concurrent recovery

The development of an efficient catalytic activation (cleavage) system for C-H and C-C bonds is an important challenge in organic synthesis, because these bonds comprise a variety of organic molecules such as natural products, petroleum oils, and polymers on the earth. Among many elegant approaches utilizing transition metals to activate C-H and C-C bonds facilely, chelation-assisted protocols based on the coordinating ability of an organic moiety have attracted great attention, though they have often suffered from the need for an intact coordinating group in a substrate. In this Account, we describe our entire efforts to activate C-H or C-C bonds adjacent to carbonyl groups by employing a new concept of metal-organic cooperative catalysis (MOCC), which enables the temporal installation of a 2-aminopyridyl group into common aldehydes or ketones in a catalytic way. Consequently, a series of new catalytic reactions such as alcohol hydroacylation, oxo-ester synthesis, C-C triple bond cleavage, hydrative dimerization of alkynes, and skeletal rearrangements of cyclic ketones was realized through MOCC. In particular, in the quest for an optimized MOCC system composed of a Wilkinson's catalyst (Ph 3P) 3RhCl and an organic catalyst (2-amino-3-picoline), surprising efficiency enhancements could be achieved when benzoic acid and aniline were introduced as promoters for the aldimine formation process. Furthermore, a notable accomplishment of C-C bond activation has been made using 2-amino-3-picoline as a temporary chelating auxiliary in the reactions of unstrained ketones with various terminal olefins and Wilkinson's catalyst. In the case of seven-membered cyclic ketones, an interesting ring contraction to five- or six-membered ones takes place through skeletal rearrangements initiated by the C-C bond activation of MOCC. On the other hand, the fundamental advances of these catalytic systems into recyclable processes could be achieved by immobilizing both metal and organic components using a hydrogen-bonded self-assembled system as a catalyst support. This catalyst-recovery system provides a homogeneous phase at high temperature during the reaction and a heterogeneous phase at room temperature after the reaction. The product could be separated conveniently from the self-assembly support system by decanting the upper layer. The immobilized catalysts of both 2-aminopyridine and rhodium metal species sustained high catalytic activity for up to the eight catalytic reactions. In conclusion, the successful incorporation of an organocatalytic cycle into a transition metal catalyzed reaction led us to find MOCC for C-H and C-C bond activation. In addition, the hydrogen-bonded self-assembled support has been developed for an efficient and effective recovery system of homogeneous catalysts and could be successful in immobilizing both metal and organic catalysts.     

A Study of the Separation of 1-Dodecene and 1-Tetradecene Hydroformylation Products in Aqueous Medium

Abstract

Experimental results of the solubilization of olefins in hydroformylation model systems, comprising 1-dodecene and 1-tridecanal or 1-tetradecene and 1-pentadecanal, water, butanol, sodium dodecylsulfate (SDS), sodium dodecylbenzenesulfonate (SDBS), and/or tri(m-sulfofenyl)phosphine trisodium salt (TPPTS-Na) are presented. The selected systems were used for the hydroformylation of 1-dodecene and 1-tetradecene whereby high yields of aldehydes were obtained. After the reaction, the mixture spontaneously separated into an organic phase with the reaction products and an aqueous phase comprising the catalyst and excess phosphine ligand.