- Two sides of the same amino acid - Development of a tandem aldol condensation/epoxidation by using the synergy of different catalytic centres in amino acids
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A new tandem catalysis was set up after intensive investigations regarding the amino catalysed aldol condensation and epoxidation. 20 proteinogenic amino acids were investigated as organocatalysts in the epoxidation of an α-branched α,β-unsaturated aldehyde. The most active amino acids were chosen for the optimization of the reaction conditions obtaining excellent yields in the epoxidation. With these insights the first tandem aldol condensation/epoxidation was developed gaining very good yields of the epoxy aldehyde, which was obtained directly from butanal without any purification or isolation of the intermediate. Applying butanal as substrate, which is produced on a large industrial scale, opens up new horizons for novel useful and reactive products. Furthermore, the beneficial influence of lysine and arginine was proven and it was revealed that these amino acids bear two different catalytic centres, which have impact on the synergy in this new tandem catalysis being active within two different reaction mechanisms. The α-amino function catalyses the aldol condensation and the corresponding side chain group is responsible for the catalytically conversion in the epoxidation.
- Ostrowski, Karoline A.,Lichte, Dominik,Terhorst, Michael,Vorholt, Andreas J.
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- Butanal Condensation Chemistry Catalyzed by Br?nsted Acid Sites on Polyoxometalate Clusters
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The connection of active site structures and their catalytic chemistry during butanal deoxygenation on polyoxometalate clusters with varying H+ site densities and identity of central atoms [HxNa4?xSiW12O40 (x=0–4) and HyNa3?yPW12O40 (y=0–3)] was established with rate assessment, IR spectroscopic, and chemical titration methods. Butanal adsorbs on the H+ or Na+ ions on polyoxometalate clusters and forms RC=O???H+ or RC=O???Na+ complexes at 348 K. A portion of the adsorbed butanals on the H+ sites converts to surface acetates through their reactions with vicinal framework oxygen atoms, as confirmed from the detection of νas(OCO) band at approximately 1580 cm?1, and remains as the spectator species. Bimolecular reactions of butanals on the remaining H+ sites lead to 2-ethyl-2-hexenal as the predominant products, within which a small fraction undergoes sequential cyclization–dehydration to produce aromatics. A trace amount of butanal converts through minor, competitive pathways that form light olefins and dienes. These findings on the connection between active sites and their catalytic chemistry provide mechanistic insights useful for tuning the rates of the various concomitant paths and thus yields towards the different products during deoxygenation reactions.
- Yang, Yifei,Lin, Fan,Tran, Honghi,Chin, Ya-Huei Cathy
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- Tailoring the cooperative acid-base effects in silica-supported amine catalysts: Applications in the continuous gas-phase self-condensation of n-butanal
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A highly efficient solid-base organocatalyst for the gas-phase aldol self-condensation of n-butanal to 2-ethylhexenal was developed by grafting site-isolated amines on tailored silica surfaces. The catalytic activity depends largely on the nature of amine species, the surface concentration of amine and silanol groups, and the spatial separation between the silanol and amine groups. In situ FTIR measurements demonstrated that the formation of nucleophilic enamines leads to the enhanced catalytic activity of secondary amine catalysts, whereas the formation of imines (stable up to 473 K) leads to the low activity observed for silica-supported primary amines. Blocking the silanol groups on the silica support by silylation or cofeeding water into the reaction stream drastically decreased the reaction rates, demonstrating that weaker acidic silanol groups participate cooperatively with the amine groups to catalyze the condensation reaction. This work demonstrates that the spatial separation of the weakly acidic silanols and amines can be tuned by the controlled dehydration of the supporting silica and by varying the linker length of the amine organosilane precursor used to graft the amine to the support surface. A mechanism for aldol condensation was proposed and then analyzed by DFT calculations. DFT analysis of the reaction pathway suggested that the rate-limiting step in aldol condensation is carbon-carbon bond formation, which is consistent with the observed kinetics. The calculated apparent activation barrier agrees reasonably with that measured experimentally. Secondary amines come first: A solid-base organocatalyst achieved by grafting amines onto silica surfaces is applied to the gas-phase aldol self-condensation of n-butanal to 2-ethylhexenal. Silica-supported secondary amine catalysts demonstrate a much higher catalytic activity than the primary amine analogues, owing to the respective formation of enamines as shown by in situ FTIR analysis. The reaction pathway is analyzed by DFT calculations.
- Shylesh, Sankaranarayanapillai,Hanna, David,Gomes, Joseph,Krishna, Siddarth,Canlas, Christian G.,Head-Gordon, Martin,Bell, Alexis T.
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- Beryllium-Induced Conversion of Aldehydes
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Aldehydes play a key role in the human metabolism. Therefore, it is essential to know their reactivity with beryllium compounds in order to assess its effects in the body. The reactivity of simple aldehydes towards beryllium halides (F, Cl, Br, I) was studied through solution and solid-state techniques and revealed distinctively different reactivities of the beryllium halides, with BeF2 being the least and BeI2 the most reactive. Rearrangement and aldol condensation reactions were observed and monitored by in situ NMR spectroscopy. Crystal structures of various compounds obtained by Be2+-catalyzed cyclization, rearrangement, and aldol addition reactions or ligation of beryllium halides have been determined, including unprecedented one-dimensional BeCl2 chains and the first structurally characterized example of an 1-iodo-alkoxide. Long-term studies showed that only aldehydes without a β-H can form stable beryllium complexes, whereas other aldehydes are oligo- and polymerized or decomposed by beryllium halides.
- Müller, Matthias,Buchner, Magnus R.
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- Vapor-phase self-aldol condensation of butanal over Ag-modified TiO2
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Vapor-phase self-aldol condensation of butanal was performed over various solid catalysts. Among the tested catalysts, SiO2-Al2O3, Nb2O5 and TiO2 showed relatively high catalytic activity for the formation of aldol condensation product, 2-ethyl-2-hexenal, whereas all the catalysts deactivated rapidly. In order to stabilize the catalytic activity, metal-modified catalysts were investigated in hydrogen flow, and it was found that Ag-modified TiO2 showed the best catalytic performance. Characterizations such as XRD, TPD, TPR, TG-DTA, and DRIFT were performed for investigating the effect of the additive Ag and analyzing the coke component. The loaded Ag metal inhibited the formation of carbon accumulated on catalyst surface, and H2 carrier gas was indispensable in the inhibition. Ag would work as a remover of the products on the catalyst surface together with H2 to prevent dehydrogenation followed by coke formation. Self-aldol condensation of butanal was stabilized over Ag-modified TiO2 at Ag2O loadings higher than 3 wt.% at 220 °C in H2 flow. TiO2 with Ag2O of 5 wt.% showed the best catalytic performance and gave a 72.2% selectivity to 2-ethyl-2-hexenal at 72.1% conversion in H2 flow at 220 °C.
- Sun, Daolai,Moriya, Shizuka,Yamada, Yasuhiro,Sato, Satoshi
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- Structured hydroxyapatite composites as efficient solid base catalysts for condensation reactions
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Herein, we report the use of structured hydroxyapatite composite (SHCs) as highly efficient and recyclable solid base catalysts for various condensation reactions. Catalyst performance as function of catalyst loading, reaction time and reaction temperature were studied in the solventless self-aldol condensation reaction of butyraldehyde to 2-ethylhexenal under mild reaction conditions. SHC catalysts were found to outperform benchmark solid base catalysts such as MgO, TiO2, calcium carbonate and hydroxyapatites. Characterization of the synthesized SHC catalysts by a range of surface analysis, spectroscopic and electron microscopy techniques, showed that a moderate acid/base ratio and high BET surface area to be key to their high efficiency. Furthermore, recycling experiments showed the catalyst to be stable over multiple runs. Moreover, the most active SHC catalyst was investigated in other prototypical condensation reactions such as the Knoevenagel condensation, Claisen-Schmidt condensation and Henry reaction, again showing excellent performance. These results highlight the versatility of these SHC materials and their potential for industrial employment as solid base catalysts.
- Bruijnincx, Pieter C. A.,Ftouni, Jamal,Jose, Tharun
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- Hierarchical Beta zeolites as catalysts in a one-pot three-component cascade Prins-Friedel-Crafts reaction
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Hierarchical Beta zeolites obtained from concentrated reaction mixtures (H2O/Si = 2.5-7.0) in the presence of CTAB and their conventional and nanosponge analogues were investigated in a one-pot cascade environmentally friendly Prins-Friedel-Crafts reaction of butyraldehyde with 3-buten-1-ol and anisole under mild conditions (60 °C). The highest yields of the desired products with 4-aryltetrahydropyran structure were achieved when using hierarchical zeolites characterised by well-developed mesoporosity (facilitating the formation of bulky intermediates and products) and by an increased fraction of highly accessible (evaluated by TTBPy method) medium-strength Br?nsted acid sites. Acid sites with higher strength promote strong adsorption of bulk O-containing intermediates or products and the formation of byproducts (tetrahydropyranyl ether and 2-propyloxan-4-ol). Therefore, this is an inexpensive and simple synthesis method for preparing hierarchical zeolites with catalytic activity comparable to that of nanosponge Beta, which is however prepared using complex and expensive multi-quaternary ammonium surfactants. Moreover, this synthetic protocol for 4-aryltetrahydropyrans replaces the carcinogenic and toxic chemicals, which have been previously used for Prins-Friedel-Crafts reactions, with green and non-toxic substances. This journal is
- ?ejka, Ji?í,Barakov, Roman,Bezverkhyy, Igor,Opanasenko, Maksym,Shcherban, Nataliya,Yaremov, Pavel
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- Cobalt-catalyzed direct α-hydroxymethylation of amides with methanol as a C1 source
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Herein, we report a cobalt-catalyzed α-hydroxymethylation of amides with methanol under mild conditions. Using CoCl2·6H2O as an inexpensive and efficient catalyst, some important bioactive β-hydroxyamides were obtained in moderate to excellent yields. The
- Ma, Ben,Sun, Rongxia,Yang, Jingya
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supporting information
p. 1382 - 1385
(2022/02/05)
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- Preparation and catalytic performance of NiO-MnO2/Nb2O5-TiO2 for one-step synthesis of 2-ethylhexanol from n-butyraldehyde
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One-pot synthesis of 2-ethylhexanol(2EHO) from n-butyraldehyde is of commercialimportance. The promotion of 2EHO selectivity requires suppressing direct hydrogenation of n-butyraldehyde. In this work, a series of NiO-MOx/Nb2O5-TiO2 catalysts were prepared and utilized by means of reduction-in-reaction technique, aiming at delaying the formation of metal sites and suppressing the direct hydrogenation. NiO-MnO2/Nb2O5-TiO2 with a Ni/Mn mass ratio of 10 and NiO-MnO2 loading of 14.3 wt% shows the best catalytic performance; 2-EHO selectivity could reach 90.0% at a complete conversion of n-butyraldehyde. Furthermore the catalyst could be used for four times without a substantial change in its catalytic performance.
- An, Hualiang,Li, Sibo,Wang, Yanji,Zhang, Jiaxun,Zhao, Xinqiang
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- READILY BIODEGRADABLE ALKOXYLATE MIXTURES
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A mixture of octanols, nonanols and decanols is useful for the preparation of alkoxylates, which alkoxylates may be used as surfactants, which surfactants have surprisingly good biodegradability.
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Paragraph 0037-0039; 0043
(2021/05/14)
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- Electronic and steric factors for enhanced selective synthesis of 2-ethyl-1-hexanol in the Ir-complex-catalyzed Guerbet reaction of 1-butanol
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1-Butanol is a potential bio-based fermentation product obtained from cellulosic biomass. As a value-added chemical, 2-ethyl-1-hexanol (2-EH) can be produced by Guerbet conversion from 1-butanol. This work reports the enhanced catalytic Guerbet reaction of 1-butanol to 2-EH by a series of Cp*Ir complexes (Cp*: 1,2,3,4,5-pentamethylcyclopenta-1,3-diene) coordinated to bipyridine-type ligands bearing an ortho-hydroxypyridine group with an electron-donating group and a Cl? anion. The catalytic activity of the Cp*Ir complex increased by increasing the electron density of the bipyridine ligand when functionalized with the para-NMe2 and ortho-hydroxypyridine groups. A record turnover number of 14047 was attained. A mechanistic study indicated that the steric effect of the ethyl group on the α-C of 2-ethylhexanal (2-EHA) and the conjugation effect of C=C–C=O in 2-ethylhex-2-enal (2-EEA) benefits the high selectivity of 2-EH from 1-butanol by inhibiting the cross-aldol reaction of 2-EHA and 2-EEA with butyraldehyde. Nuclear magnetic resonance study revealed the formation of a carbonyl group in the bipyridine-type ligand via the reaction of the Cp*Ir complex with KOH.
- Xu, Zhanwei,Yan, Peifang,Liang, Changhui,Jia, Songyan,Liu, Xiumei,Zhang, Z. Conrad
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p. 1586 - 1592
(2021/05/10)
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- SELF-CONDENSATION OF ALDEHYDES
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An efficient process useful for the self-condensation of aliphatic aldehydes is provided, catalyzed by dialkylammonium carboxylate salts. In particular, the invention provides a facile method for the preparation of 2-ethyl hexenal via the self-condensation of butyraldehyde using various dialkylammonium carboxylates, e.g., diisopropylammonium acetate or dimethylammonium acetate, as catalyst. Additionally, residual nitrogen arising from the catalyst can be reduced to -100 ppm levels in the product via a simple washing procedure. The invention provides a process for preparing alkenals under conditions which limit the formation of undesired impurities and high-boiling oligomeric substances.
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Paragraph 0019-0020; 0022; 0024; 0028
(2020/06/05)
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- METHOD FOR PRODUCING CROSS ALDOL CONDENSATE USING AMINE-CARRYING CATALYST
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PROBLEM TO BE SOLVED: To provide a method for producing a cross aldol condensate with improved selectivity of a cross aldol condensate, the target material. SOLUTION: A method for producing a cross aldol condensate has a step of performing a cross aldol condensation reaction of different two substrates in the presence of an amine-carrying catalyst with an amine compound immobilized to a carrier, the substrate containing two compounds selected from aldehyde and/or ketone having α hydrogen. SELECTED DRAWING: None COPYRIGHT: (C)2021,JPO&INPIT
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Paragraph 0033; 0037; 0043
(2021/01/16)
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- Amorphous SiO2 catalyst for vapor-phase aldol condensation of butanal
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Vapor-phase aldol condensation of butanal to form 2-ethyl-2-hexenal was carried out over several oxide catalysts such as SiO2-Al2O3, Al2O3, ZrO2, and SiO2. Catalysts with moderate and strong acid sites such as Al2O3 and SiO2-Al2O3 were active for the reaction in the initial period, whereas they deactivated rapidly. In contrast, SiO2 with weak acidity showed a low but a stable catalytic activity for the formation of 2-ethyl-2-hexenal. Thermogravimetric analyses of the samples used after the reactions indicate that SiO2 has the smallest amount of carbonaceous species that contributed to its stable activity among the tested catalysts. SiO2 catalysts with different pore sizes and specific surface areas were examined: SiO2 with a mean pore diameter of 10 nm and a surface area of 295 m2 g?1 showed the best catalytic performance and gave a 2-ethyl-2-hexenal selectivity of 90% at a conversion of 48% at 240 °C. In the catalytic test using deuterated SiO2, which was prepared by contacting SiO2 with deuterated water before the reaction, it was confirmed by a mass spectrometer that the deuterium atom of SiOD was transferred to a 2-ethyl-2-hexenal molecule during the reaction. It is indicated that silanol groups on the SiO2 surface played a role as an active site.
- Sun, Daolai,Yamada, Yasuhiro,Sato, Satoshi
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p. 113 - 119
(2018/11/25)
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- AROMA CHEMICAL COMPOSITIONS CONTAINING 3,5-DIETHYL-2-PROPYL-TETRAHYDROPYRAN AND/OR UNSATURATED DERIVATIVES THEREOF
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The present invention relates to aroma chemical compositions containing 3,5-diethyl-2-propyl-tetrahydropyran, a 3,5-diethyl-2-propyl-dihydropyran or a 3,5-diethyl-2-propyl-pyran, a mixture of such compounds, a stereoisomer of one of these compounds, or a mixture of stereoisomers of one or more of these compounds. The invention further relates to a method for preparing such compounds, stereoisomers or mixtures thereof, to the composition obtainable by this method, to the use of such compounds as an aroma chemicalor for modifying the scent character of a fragranced composition; and to a method for preparing a fragranced composition or for modifying the scent character of a fragranced composition using said compounds. Moreover, the invention relates to 3,5-diethyl-2-propyl-tetrahydropyran, to its stereoisomers and to mixtures of these stereoisomers.
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Page/Page column 56
(2019/04/27)
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- Method for preparing high-carbon branched-chain secondary alcohol
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The invention relates to a method for preparing high-carbon branched-chain secondary alcohol. The method comprises the steps: preparing branched-chain olefin aldehyde through self-condensation of linear aliphatic aldehyde or branched-chain aliphatic aldehyde without tertiary carbon, performing a gas-liquid heterogeneous condensation reaction on the branched-chain olefin aldehyde and aliphatic ketone without tertiary carbon under the catalysis action of organic base so as to prepare branched-chain dienone, and performing hydrogenation on the branched-chain dienone so as to prepare unsaturated or saturated branched-chain secondary alcohol. The method has wide sources of raw materials and low cost, and the product has a certain structure, and is particularly suitable for preparation of secondary alcohol polyoxyethylene ether and secondary alcohol polyoxyethylene ether derivatives which have narrow molecular weight distribution; and the alcoholic hydroxyl group of the product is secondary alcohol which has a branched-chain structure but no tertiary carbon, the low temperature performance is excellent, and the biodegradability is good.
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Paragraph 0050; 0051
(2019/10/01)
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- Method for catalyzing aldol self-condensation reaction of low-carbon aldehyde by acid alkali double-function ionic liquid
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The invention relates to a method for catalyzing aldol self-condensation reaction of low-carbon aldehyde by acid alkali double-function ionic liquid. The method comprises the following steps: adding low-carbon aldehyde and an acid alkali double-function ionic liquid catalyst into a high-pressure kettle, reacting at 60 to 150 DEG C for 1 to 12 hours, and performing hydroxyaldehyde self-condensationreaction on the low-carbon aldehyde to obtain long-chain unsaturated aldehyde, wherein the acid alkali double-function ionic liquid is the acid alkali double-function ionic liquid with cation and anion containing acid and alkali groups correspondingly, or the novel acid alkali double-function ionic liquid with cation containing acid and alkali groups. The method is applied to aldol self-condensation reaction of n-butanal and n-pentanal and is mild in reaction condition, high in catalytic activity and high in selectivity; and the acid alkali double-function ionic liquid catalyst can be reused.
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Paragraph 0058-0059; 0062
(2018/03/01)
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- CONVERSION OF ALCOHOLS TO LINEAR AND BRANCHED FUNCTIONALIZED ALKANES
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Embodiments herein concerns the eco-friendly conversion of simple alcohols to linear or branched functionalized alkanes, by integrated catalysis. The alcohols are firstlyoxidized either chemically or enzymatically to the corresponding aldehydes or ketones, followed by aldol condensations using a catalyst to give the corresponding enals or enones. The enals or enones are subsequently and selectively hydrogenated using a recyclable heterogeneous metal catalyst, organocatalyst or an enzyme to provide linear or branched functionalized alkanes with an aldehyde, keto- or alcohol functionality. The process is also iterative and can be further extended by repeating the above integrated catalysis for producing long-chain functionalized alkanes from simple alcohols.
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Page/Page column 10-11
(2018/03/09)
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- Vanadium-Catalyzed Condensation of Ethyl Cyanoacetate with Ketones
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Vanadium compounds and complexes activated by pyridine or morpholine catalyze condensation of ethyl cyanoacetate with ketones and aldehydes leading to alkylidenecyanoacetates in 75–100% yield.
- Khusnutdinov,Shchadneva,Mayakova, Yu. Yu.
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p. 403 - 409
(2018/04/24)
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- Engineering a Promiscuous Tautomerase into a More Efficient Aldolase for Self-Condensations of Linear Aliphatic Aldehydes
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The enzyme 4-oxalocrotonate tautomerase (4-OT) from Pseudomonas putida mt-2 takes part in a catabolic pathway for aromatic hydrocarbons, where it catalyzes the conversion of 2hydroxyhexa-2,4-dienedioate into 2-oxohexa-3-enedioate. This tautomerase can also promiscuously catalyze carbon–carbon bond-forming reactions, including various types of aldol reactions, by using its amino-terminal proline as a key catalytic residue. Here, we used systematic mutagenesis to identify two hotspots in 4-OT (Met45 and Phe50) at which single mutations give marked improvements in aldolase activity for the self-condensation of propanal. Activity screening of a focused library in which these two hotspots were varied led to the discovery of a 4-OT variant (M45Y/F50V) with strongly enhanced aldolase activity in the self-condensation of linear aliphatic aldehydes, such as acetaldehyde, propanal, and butanal, to yield α,β-unsaturated aldehydes. With both propanal and benzaldehyde, this double mutant, unlike the previously constructed single mutant F50A, mainly catalyzes the self-condensation of propanal rather than the cross-condensation of propanal and benzaldehyde, thus indicating that it indeed has altered substrate specificity. This variant could serve as a template to create new biocatalysts that lack dehydration activity and possess further enhanced aldolase activity, thus enabling the efficient enzymatic self-coupling of aliphatic aldehydes.
- Rahimi, Mehran,van der Meer, Jan-Ytzen,Geertsema, Edzard M.,Poelarends, Gerrit J.
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p. 1435 - 1441
(2017/07/25)
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- SINGLE-STEP CONVERSION OF N-BUTYRALDEHYDE TO 2-ETHYLHEXANAL
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Disclosed is a method of making and using a titania supported palladium catalyst for the single step synthesis of 2-ethylhexanal from a feed of n-butyraldehyde. This titania supported palladium catalyst demonstrates high n-butyraldehyde conversion but also produces 2-ethylhexanal in an appreciable yield with maintained activity between runs. This method provides a single step synthesis of 2-ethylhexanal from n-butyraldehyde with a catalyst that can be regenerated that provides cleaner downstream separations relative to the traditional caustic route.
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Paragraph 00130; 00133
(2017/08/21)
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- P-Toluene sulfonic acid (PTSA)-MCM-41 as a green, efficient and reusable heterogeneous catalyst for the synthesis of jasminaldehyde under solvent-free condition
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This paper reports the synthesis of p-Toluene sulfonic acid (PTSA)-MCM-41 by impregnation method and its characterization XRD, FT-IR, TGA, N2 adsorption-desorption isotherms, SEM, and TEM. The impregnated catalysts were used to catalyse cross-aldol condensation of active methylene bearing aliphatic aldehydes with aromatic aldehydes under solvent and metal-free condition particularly in the synthesis perfumery chemical-jasminaldehyde and related compounds. The as synthesized catalyst PTSA-MCM-41 has displayed high efficiency (selectivity up to 91%) in catalyzing cross-aldol condensation reaction and was reusable (5 cycles) with no apparent loss in activity. The catalytic performance of PTSA-MCM-41 was compared with other catalysts viz., ZnO, proline, proline-LDH, PTSA, PTSA-zirconia and PTSA-zeolite where PTSA-MCM-41 showed better performance particularly in synthesis of jasminaldehyde.
- Ganga, Venkata Subba Rao,Abdi, Sayed H.R.,Kureshy, Rukhsana I.,Khan, Noor-Ul H.,Bajaj, Hari C.
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p. 264 - 271
(2016/05/19)
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- Synthesis of 2-ethyl-2-hexenal, the method
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The present invention relates to a method for synthesizing 2-ethyl-2-hexenal. The method comprises that: 2-ethyl hexanol and butyraldehyde are mixed according to a mass ratio of 0.1-10; a condensation dehydration reaction is performed at a temperature of 80-220 DEG C under pressure of 0.1-1.0 MPa under an effect of a solid base to obtain a single-phase mixture of 2-ethyl-2-hexenal, 2-ethyl hexanol and water; the reactant is distilled at a temperature of 100-110 DEG C under pressure of 0.1-0.15 MPa, the unreacted butyraldehyde circularly returns to the condensation reactor, and an organic phase and aqueous phase two-phase mixture of 2-ethyl-2-hexenal and 2-ethyl hexanol is extracted; and the organic phase and aqueous phase two-phase mixture is subjected to condensation and chromatography separation to obtain a 2-ethyl-2-hexenal and 2-ethyl hexanol mixture. With the method, the 2-ethyl-2-hexenal yield achieves 96%, the loss of the catalyst active ingredient is less, no basic organic wastewater is generated, and the solvent is not required to be separated and recovered.
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Paragraph 0023-0024
(2017/02/23)
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- Supported homogeneous catalyst makes its own liquid phase
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A catalyst designed for homogeneous catalysis is shown to generate its own liquid phase if deposited onto a support. In this way, a macroscopically heterogeneous catalyst generates a microscopically homogeneous catalytic environment by self-organization. 2,2′-((3,3′-di-tert-butyl-5,5′-dimethoxy-[1,1′-biphenyl]-2,2′-diyl)-bis(oxy))bis(4,4,5,5-tetraphenyl-1,3,2-dioxaphospholane) modified rhodium complexes molecularly adsorbed onto porous silica powder show surprisingly high activity and regioselectivity in the gas-phase hydroformylation of propene to butanal, with no sign of deactivation. Operando IR investigations combined with density functional theory calculations confirm a side reaction: the aldol condensation of the butanal products. These heavier by-products accumulate inside the pores of the catalytic material. IR and gas chromatography show a direct relation between formation of enones, products of the aldol condensation, performance, and stability of the catalytic system. This demonstrates that the aldol condensation products generated in situ act as a solvent providing an ideal environment to the impregnated homogeneous catalyst.
- Kaftan, Andre,Sch?nweiz, Andreas,Nikiforidis, Ioannis,Hieringer, Wolfgang,Dyballa, Katrin M.,Franke, Robert,G?rling, Andreas,Libuda, J?rg,Wasserscheid, Peter,Laurin, Mathias,Haumann, Marco
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- N-Butyraldehyde self-condensation catalyzed by Ce-modified γ-Al2O3
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Self-condensation of n-butyraldehyde is an important process for the industrial production of 2-ethylhexanol. The catalytic performance of some solid acids such as γ-Al2O3 and molecular sieves for the self-condensation of n-butyraldehyde was investigated and the results showed that γ-Al2O3 was the best one. Then the effect of preparation conditions on the catalytic performance of γ-Al2O3 and the effect of reaction conditions on the self-condensation of n-butyraldehyde were discussed. In order to improve the catalytic performance, γ-Al2O3 was modified by different substances and Ce-Al2O3 was found to show the best catalytic performance; the conversion of n-butyraldehyde and the yield of 2-ethyl-2-hexenal could reach 93.8% and 88.6%, respectively. Moreover, the Ce-Al2O3 catalyst had excellent reusability. The XPS analysis of Ce3d demonstrated that the valence state of cerium affected the catalytic performance of Ce-Al2O3 to some extent but not predominantly. Instead the acid-base property of Ce-Al2O3 played a dominant role in the catalytic performance. The reaction components formed over the Ce-Al2O3 catalyst were identified by GC-MS and then some side-reactions were speculated and a reaction network for n-butyraldehyde self-condensation catalyzed by Ce-Al2O3 was proposed. Subsequently, the research on the intrinsic kinetics of n-butyraldehyde self-condensation catalyzed by Ce-Al2O3 showed that both the forward and backward reactions are second order and the corresponding activation energy is separately 79.60 kJ mol-1 and 74.30 kJ mol-1, which is higher than that of the reaction catalyzed by an aqueous base or acid.
- Xiong, Chao,Liang, Ning,An, Hualiang,Zhao, Xinqiang,Wang, Yanji
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p. 103523 - 103533
(2015/12/23)
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- Direct synthesis of 2-ethylhexanol via n-butanal aldol condensation-hydrogenation reaction integration over a Ni/Ce-Al2O3 bifunctional catalyst
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Direct synthesis of 2-ethylhexanol from n-butanal via the reaction integration of n-butanal self-condensation with 2-ethyl-2-hexenal hydrogenation is of crucial interest for industrial production of 2-ethylhexanol. Furthermore, as an important and versatile chemical, n-butanol can be produced simultaneously by reaction integration. In the present work, several bifunctional catalysts based on γ-Al2O3 were prepared by the impregnation method and were characterized by means of H2-TPR, XRD, TEM and H2-TPD, and their catalytic performance for direct synthesis of 2-ethylhexanol from n-butanal was investigated. The results showed that Co/Al2O3 had a low activity for hydrogenation and Cu/Al2O3 had a high selectivity for the hydrogenation of the C=O group while a Ru/Al2O3 catalyst only favored the hydrogenation of n-butanal to n-butanol. Among them, the Ni/Al2O3 catalyst showed the best catalytic performance and the yield of 2-ethylhexanol was the highest (49.4%). Ce-modified Ni/Al2O3 enhanced the competitiveness of aldol condensation versus hydrogenation of n-butanal and improved the selectivity of 2-ethylhexanol; the yield of 2-ethylhexanol rose to 57.8%. Then the influence of preparation conditions on the catalytic performance of Ni/Ce-Al2O3 was investigated and the suitable preparation conditions were obtained as follows: Ni loading = 10%, calcined at 550 °C for 5 h, and reduced at 570 °C for 4 h. The effect of reaction conditions on the integration reaction catalyzed by Ni/Ce-Al2O3 was investigated and the suitable reaction conditions were obtained as follows: weight percentage of Ni/Ce-Al2O3 = 15%, reaction temperature = 170 °C, reaction pressure = 4.0 MPa and reaction time = 8 h. Under the above reaction conditions, the yield of 2-ethylhexanol attained 66.9% and that of n-butanol was 18.9%. In addition, the components existing in the integration reaction system were identified by GC-MS analysis, and the main by-products were n-butyl butyrate, 2-ethylhexyl butyrate, n-butyric acid, etc. Based on the analysis of the reaction system, a reaction network for the direct synthesis of 2-ethylhexanol from n-butanal was proposed. Finally, an evaluation of the reusability of Ni/Ce-Al2O3 showed that the recovered Ni/Ce-Al2O3 catalyst lost its catalytic activity for the hydrogenation of the C=O group. The main reason for deactivation was that Ni species were covered by the flaky boehmite γ-AlO(OH) formed from the hydration of γ-Al2O3 in the reaction process.
- Liang, Ning,Zhang, Xiaolong,An, Hualiang,Zhao, Xinqiang,Wang, Yanji
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p. 2959 - 2972
(2015/05/27)
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- Metal-free oxidative decarbonylative coupling of aromatic aldehydes with arenes: Direct access to biaryls
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A metal-free oxidative decarbonylative coupling of aromatic aldehydes with electron-rich or electron-deficient arenes to produce biaryl compounds was developed. This novel coupling was proposed to proceed via a non-chain radical homolytic aromatic substitution (HAS) type mechanism, based on the substrate scope, ortho-regioselectivity, radical trapping experiments and DFT calculation studies. With the ready availability of aromatic aldehydes and arenes, metal-free conditions should make this coupling attractive for the biaryl synthesis.
- Tang, Ren-Jin,He, Qing,Yang, Luo
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p. 5925 - 5928
(2015/03/30)
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- APPARATUS AND METHOD FOR PREPARING ALCOHOL FROM OLEFIN
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Disclosed are an apparatus and method for preparing alcohol from olefin. A reactor for hydroformylating olefin comprises a loop reactor for reducing high-boiling point components, a post-treatment device for separating aldehyde comprises a catalyst/aldehyde separator and a divided wall column (DWC) for removing remaining high-boiling point components, and a post-treatment device for separating alcohol comprises a divided wall column (DWC) for removing remaining high-boiling point components. The apparatus and method for preparing alcohol reduce production of high-boiling point components in the preparation of alcohols and efficiently remove remaining high-boiling point components, thus obtaining alcohol containing no high-boiling point components.
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Paragraph 0092-0095
(2014/11/13)
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- Photocatalytic degradation of water taste and odour compounds in the presence of polyoxometalates and TiO2: Intermediates and degradation pathways
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Geosmin (GSM) and 2-methylisoborneol (MIB) are produced by several species of cyanobacteria and actinomycetes. These compounds can taint water and fish causing undesirable taste and odours. Studies have shown that GSM/MIB are resistant in standard water treatments. Polyoxometalates (POM) are efficient photocatalysts in the degradation and mineralization of a great variety of organic pollutants, presenting similar behaviour with the widely published titanium dioxide (TiO2). Photocatalytic degradation of GSM and MIB under UV-A light in the presence of a characteristic POM photocatalyst, SiW 12O404-, in aqueous solution has been studied and compared with the photodegradation by TiO2 suspensions. GSM and MIB are effectively degraded in the presence of both photocatalysts. Addition of OH radical scavengers (KBr and tertiary butyl alcohol, TBA) retards the photodegradation rates of both compounds, suggesting that photodegradation mechanism takes place via OH radicals. Intermediates identified using GC-MS in the case of GSM and MIB, are mainly identical in the presence of both photocatalysts, also suggesting a common reaction mechanism. Possible photocatalytic degradation pathway for both GSM and MIB is proposed.
- Fotiou, Theodora,Triantis, Theodoros M.,Kaloudis, Triantafyllos,Papaconstantinou, Elias,Hiskia, Anastasia
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- Method for Carrying Out Multiphase Aldol Condensation Reactions to Give Mixed a, beta-Unsaturated Aldehydes
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The invention relates to a continuous method for carrying out a multiphase aldol condensation reaction to obtain mixed α, β-unsaturated aldehydes by reacting a mixture of two aliphatic aldehydes having different numbers of carbon atoms, i.e. 2 to 5, in the molecule in a vertical tubular reactor in a concurrent flow in the presence of an aqueous solution of a basically reacting compound. In said method, the aldehyde mixture is dispersed in the aqueous phase in the form of drops, and the aqueous solution of the basically reacting compound flows through the tubular reactor as a continuous phase in laminar conditions.
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Paragraph 0058-0061
(2014/02/15)
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- Catalyst and process to produce branched unsaturated aldehydes
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A continuous process and system for preparing branched aldehydes by reacting aldehyde with an acid polymeric catalyst absent any metal from Group VIII to produce a product having about 10 to 99.99% by weight branched unsaturated aldehyde and at least 92% selectivity of reaction to the branched aldehyde and recycling a portion of the product.
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Paragraph 0049
(2013/07/25)
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- Aerobic oxidative coupling of alcohols and amines over Au-Pd/resin in water: Au/Pd molar ratios switch the reaction pathways to amides or imines
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A facile switch of the reaction pathways of aerobic oxidative coupling of alcohols and amines from amidation to imination was realized for the first time by tuning the Au/Pd ratios in ion-exchange resin supported Au-Pd alloy catalysts (Au-Pd/resin). Amides were obtained with high yields on Au6Pd/resin while imines were obtained over AuPd4/resin. Various alcohols and amines underwent oxidative coupling smoothly in water to afford the desired products with good to excellent yields. Further investigation on the reaction mechanism suggested the synergistic effect between Au and Pd determined the adsorption strength of the aldehyde intermediate, which in turn dictated the reaction pathways. That is, on Au-rich alloys (e.g., Au6Pd) absorbed aldehyde species was formed, followed by further oxidation to yield amides, while on Pd-rich alloys (e.g., AuPd4), free aldehyde was generated, which then underwent condensation with amines to produce imines. The discovery might provide avenues to develop new efficient catalysts for the green synthesis of special chemicals.
- Zhang, Leilei,Wang, Wentao,Wang, Aiqin,Cui, Yitao,Yang, Xiaofeng,Huang, Yanqiang,Liu, Xiaoyan,Liu, Wengang,Son, Jin-Young,Oji, Hiroshi,Zhang, Tao
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supporting information
p. 2680 - 2684
(2013/10/08)
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- Novel basic ionic liquid based on alkylammonium as efficient catalyst for Knoevenagel reaction
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The typical Knoevenagel condensation was carried out smoothly in the presence of a basic ionic liquid of N,N,N′,N′-tetramethyl-N′- hexyl-ethylenediammonium tetrafluoroborate ([TMHEDA]BF4), and 99% of yield was obtained using ethyl cyanoacetate and benzaldehyde as substrates at 60 °C for 1 h. Four reuses of the ionic liquid without dramatic decrease in catalytic activity for Knoevenagel condensation demonstrated the good stability and operability of the ionic liquid. Moreover, the typical nucleophilic addition reactions were also accomplished by the same ionic liquid to check its feasibility. The dual function of the basic ionic liquid both as solvent and catalyst, combined with simple product separation and recycling, is expected to contribute to the development of a green and environmentally friendly strategy. Copyright Taylor & Francis Group, LLC.
- Zhou, Shuai,Liu, Lu,Wang, Bo,Ma, Mingguo,Xu, Feng,Sun, Runcang
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experimental part
p. 1384 - 1391
(2012/04/10)
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- Preparation and synergetic catalytic effects of amino-functionalized MCM-41 catalysts
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Four amine functionalized mesoporous catalysts were synthesized by grafting primary, dualistic and two secondary amines onto the channel walls of mesoporous silica, MCM-41. We examined the effects of organoamine loading amount on the acid-base synergism of the catalysts in the self-condensation reaction of n-butanal, a Knoevenagel condensation and a Henry reaction. We observed the balance of the amine and residual silanol amounts is crucial to the catalytic performances of the functionalized mesoporous catalysts. An optimum organoamine loading amount exists, which is dependent on the organoamine type. There is little difference in the optimum organoamine loading amount between different reactions. The secondary organoamine functionalized MCM-41 exhibits the best catalytic performance in the experimental range.
- Lang, Wanzhong,Su, Bo,Guo, Yajun,Chu, Lianfeng
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experimental part
p. 1167 - 1174
(2012/09/08)
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- CONVERSION OF BUTANOL TO A REACTION PRODUCT COMPRISING 2-ETHYLHEXANOL USING HYDROXYAPATITE CATALYSTS
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Catalytic processes to produce a reaction product comprising 2-ethylhexanol by contacting a reactant comprising 1-butanol with a catalyst composition under suitable reaction conditions are provided. The catalyst composition may comprise a hydroxyapatite of the Formula (MwM′xM″yM′″z)5(PO4)3(OH), wherein M is Mg; M′ is Ca; M″ is Sr; M′″ is Ba; w is any number between 0 and 1 inclusive; x is any number from 0 to less than 0.5; y is any number between 0 and 1 inclusive; z is any number between 0 and 1 inclusive; and w+x+y+z=1. Base-treated catalyst compositions may be used.
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Page/Page column 9-10
(2012/09/22)
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- Organocatalyzed michael addition of aldehydes to nitro alkenes - Generally accepted mechanism revisited and revised
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The amine-catalyzed enantioselective Michael addition of aldehydes to nitro alkenes (Scheme 1) is known to be acid-catalyzed (Fig. 1). A mechanistic investigation of this reaction, catalyzed by diphenylprolinol trimethylsilyl ether is described. Of the 13 acids tested, 4-NO2-C6H 4OH turned out to be the most effective additive, with which the amount of catalyst could be reduced to 1 mol-% (Tables 2-5). Fast formation of an amino-nitro-cyclobutane 12 was discovered by in situ NMR analysis of a reaction mixture. Enamines, preformed from the prolinol ether and aldehydes (benzene/molecular sieves), and nitroolefins underwent a stoichiometric reaction to give single all-trans-isomers of cyclobutanes (Fig. 3) in a [2+2] cycloaddition. This reaction was shown, in one case, to be acid-catalyzed (Fig. 4) and, in another case, to be thermally reversible (Fig. 5). Treatment of benzene solutions of the isolated amino-nitro-cyclobutanes with H2O led to mixtures of 4-nitro aldehydes (the products 7 of overall Michael addition) and enamines 13 derived thereof (Figs. 6-9). From the results obtained with specific examples, the following tentative, general conclusions are drawn for the mechanism of the reaction (Schemes 2 and 3): enamine and cyclobutane formation are fast, as compared to product formation; the zwitterionic primary product 5 of C,C-bond formation is in equilibrium with the product of its collapse (the cyclobutane) and with its precursors (enamine and nitro alkene); when protonated at its nitronate anion moiety the zwitterion gives rise to an iminium ion 6, which is hydrolyzed to the desired nitro aldehyde 7 or deprotonated to an enamine 13. While the enantioselectivity of the reaction is generally very high (>97% ee), the diastereoselectivity depends upon the conditions, under which the reaction is carried out (Fig. 10 and Table 1-5). Various acid-catalyzed steps have been identified. The cyclobutanes 12 may be considered an off-cycle 'reservoir' of catalyst, and the zwitterions 5 the 'key players' of the process (bottom part of Scheme 2 and Scheme 3). Copyright
- Patora-Komisarska, Krystyna,Benohoud, Meryem,Ishikawa, Hayato,Seebach, Dieter,Hayashi, Yujiro
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scheme or table
p. 719 - 745
(2011/06/27)
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- APPARATUS FOR PRODUCING ALCOHOLS FROM OLEFINS
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The present invention relates to an apparatus for producing alcohols from olefins, comprising: a hydroformylation reactor wherein aldehydes are produced from olefins; a catalyst/aldehydes separator; a hydrogenation reactor wherein the aldehydes are hydrogenated to produce alcohols; and a distillation column. The hydroformylation reactor is equipped with a distributor plate, which has a broad contact surface for providing sufficient reaction area for reactants such as olefins and synthesis gas, and allows the reaction mixture to circulate and mix sufficiently, which contribute to excellent efficiency in terms of production of aldehydes. In addition, the hydrogenation reactor suppresses sub-reactions to improve the production yield of alcohols.
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Page/Page column 9
(2011/11/30)
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- APPARATUS FOR PRODUCING ALCOHOLS FROM OLEFINS
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The present invention relates to an apparatus for producing alcohols from olefins, comprising: a hydroformylation reactor wherein aldehydes are produced from olefins; a catalyst/aldehydes separator; a hydrogenation reactor wherein the aldehydes are hydrogenated to produce alcohols; and a distillation column. The hydroformylation reactor is equipped with a distributor plate, which has a broad contact surface for providing sufficient reaction area for reactants such as olefins and synthesis gas, and allows the reaction mixture to circulate and mix sufficiently, which contribute to excellent efficiency in terms of production of aldehydes. In addition, the hydrogenation reactor suppresses sub-reactions to improve the production yield of alcohols.
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Page/Page column 12
(2011/12/12)
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- Conversion of biomass-derived butanal into gasoline-range branched hydrocarbon over Pd-supported catalysts
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For production of gasoline-range branched hydrocarbon from butanal, Pd catalysts supported on different metal oxides were applied. Among the prepared catalysts, Pd/ZrO2 showed the complete butanal conversion with the formation of C7-to-C9 branched hydrocarbon (75% yield). Additionally, the ratios of O/C and straight-chain to branched hydrocarbon (n-C/br-C) were found to be 0.005 and 0.17, respectively. This indicates that an adequate combination of Pd dispersion and amphoteric ZrO2 character promoted hydrodeoxygenation, C-C coupling and isomerization reactions. Consequently, both Pd dispersion and acid-base properties of supports are suggested to play a pivotal role in producing gasoline-range hydrocarbon at a high yield.
- Kim, Sung Min,Lee, Mi Eun,Choi, Jae-Wook,Suh, Dong Jin,Suh, Young-Woong
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scheme or table
p. 108 - 113
(2012/03/10)
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- NMR investigations on the proline-catalyzed aldehyde self-condensation: Mannich mechanism, dienamine detection, and erosion of the aldol addition selectivity
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The proline-catalyzed self-condensation of aliphatic aldehydes in DMSO with varying amounts of catalyst was studied by in situ NMR spectroscopy. The reaction profiles and intermediates observed as well as deuteration studies reveal that the proline-catalyzed aldol addition and condensation are competing, but not consecutive, reaction pathways. In addition, the rate-determining step of the condensation is suggested to be the C-C bond formation. Our findings indicate the involvement of two catalyst molecules in the C-C bond formation of the aldol condensation, presumably by the activation of both the aldol acceptor and donor in a Mannich-type pathway. This mechanism is shown to be operative also in the oligomerization of acetaldehyde with high proline amounts, for which the first in situ detection of a proline-derived dienamine was accomplished. In addition, the diastereoselectivity of the aldol addition is evidenced to be time-dependent since it is undermined by the retro-aldolization and the competing irreversible aldol condensation; here NMR reaction profiles can be used as a tool for reaction optimization.
- Schmid, Markus B.,Zeitler, Kirsten,Gschwind, Ruth M.
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supporting information; scheme or table
p. 3005 - 3015
(2011/06/28)
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- On the mechanism of the chemiluminescent condensation of aniline with butyraldehyde catalyzed by LnCl3 ? 6H2O
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The mechanism of the chemiluminescent condensation of aniline with butyraldehyde into 3-ethyl-2-propylquinoline catalyzed by LnCl3 ? 6H2O (Ln = Tb, Ho) is reported. A likely scheme of the catalytic condensation of aniline with butyraldehyde has been developed by simulation of separate steps of the reaction using chemiluminescence and photoluminescence methods and quantum-chemical calculations of the heats of these steps.
- Bulgakov,Kuleshov,Makhmutov,Dzhemilev
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body text
p. 534 - 541
(2011/01/06)
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- A green method for the self-aldol condensation of aldehydes using lysine
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A self-condensation of aldehydes has been conveniently accomplished by the catalytic action of lysine in water or a solvent-free system under specific emulsion conditions to give α-branched α,β-unsaturated aldehydes in good yields.
- Watanabe, Yutaka,Sawada, Kazue,Hayashi, Minoru
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experimental part
p. 384 - 386
(2010/08/04)
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- Amino functionalized chitosan as a catalyst for selective solvent-free self-condensation of linear aldehydes
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An aminopropyltrimethoxysilane functionalized chitosan was found to be an efficient solid base catalyst for the self-aldol condensation of linear aldehydes under solvent-free conditions. The modified catalyst was characterized using physical techniques, elemental analysis, FT-IR, and TGA. The modified chitosan was evaluated for the aldol condensation of C3-C7 linear aldehydes in which the selective formation was obtained for α,β-unsaturated aldehydes. A decreasing trend in the conversion from propanal to heptanal was observed. Propanal and pentanal were subjected for detail investigations to study the effect of parameters like amount of catalyst and aldehyde, and temperature on the conversion and selectivity. Kinetic performance of the modified chitosan investigated for a representative aldehyde, pentanal showed that the rate was increased with the catalyst amount, pentanal and temperature. The catalyst was reused up to six cycles without significant loss in its activity and selectivity.
- Jose, Tharun,Sudheesh,Shukla, Ram S.
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experimental part
p. 158 - 166
(2011/02/23)
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- Cooperative organocatalysis for the asymmetric γ alkylation of α-branched enals
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α Branched leads to γ: The direct and enantioselective γ alkylation of α-substituted α,β-unsaturated aldehydes under dienamine catalysis has been achieved. A cooperative catalysis system that involves dienamine activation of α-branched enals and chiral Bronsted acid catalysis promotes an SN1-alkylation pathway while ensuring complete γ-site selectivity and high stereocontrol (see scheme; Bn=benzyl). Copyright
- Bergonzini, Giulia,Vera, Silvia,Melchiorre, Paolo
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supporting information; experimental part
p. 9685 - 9688
(2011/03/16)
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- The continuous self aldol condensation of propionaldehyde in supercritical carbon dioxide: A highly selective catalytic route to 2-methylpentenal
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The aldol reactions of propionaldehyde and butyraldehyde have been explored in supercritical CO2, scCO2, using an automated continuous flow reactor. The reaction was found to proceed over a variety of heterogeneous acidic and basic catalysts and with increased selectivity compared to using neat reactants.
- Stevens, James G.,Bourne, Richard A.,Poliakoff, Martyn
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scheme or table
p. 409 - 416
(2010/04/22)
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- Asymmetric organocatalytic cascade reactions with a-substituted α,β-unsaturated aldehydes
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Time to α-branch out! The first highly enantioselective aminocatalytic activation of a-substituted αβ-unsaturated aldehydes is presented. The chiral primary amine 1 selectively activates ct-branched enals toward a well-defined iminium ion enamine reaction sequence for both Friedel-Crafts/amination and sulfa-Michael/ amination cascades. The valuable multifunctional products, having two contiguous sterocenters, are isolated in high enantiomeric purity.
- Galzerano, Patrizia,Pesciaioli, Fabio,Mazzanti, Andrea,Bartoli, Giuseppe,Melchiorre, Paolo
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supporting information; body text
p. 7892 - 7894
(2010/04/06)
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- Stereospecific synthesis of conformationally constrained γ-amino acids: New foldamer building blocks that support helical secondary structure
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(Figure Presented) A highly stereoselective synthesis of novel cyclically constrained γ-amino acid residues is presented. The key step involves organocatalytic Michael addition of an aldehyde to 1-nitrocyclohexene. After aldehyde reduction, this approach provides optically active β-substituted δ-nitro alcohols (96-99% ee), which can be converted to γ-amino acid residues with a variety of substituents at the α position. We have used these new building blocks to prepare α/γ-peptide foldamers that adopt a specific helical conformation in solution and in the solid state. Copyright
- Guo, Li,Chi, Yonggui,Almeida, Aaron M.,Guzei, Ilia A.,Parker, Brian K.,Gellman, Samuel H.
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scheme or table
p. 16017 - 16020
(2010/02/15)
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- Process for Production of Purified Alcohols
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A process for producing purified alcohols yielding good results in the acid wash color test which comprises the condensation step of subjecting an aldehyde to aldol condensation and dehydration to obtain a corresponding condensate, the hydrogenation step of hydrogenating the condensate into a crude alcohol, and the purification step of distilling the crude alcohol to obtain a purified alcohol, characterized by feeding into the purification step a crude alcohol containing compounds having oxygenic heterocycles bearing carbon-carbon double bonds in the cycle in a concentration of as low as 200 ppm by weight or below. In particular, the aldehyde is n-butyraldehyde, the condensate is 2-ethylhexenal, and the alcohol is 2-ethylhexanol.
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Page/Page column 4-6
(2008/12/07)
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- Palladium supported on an acidic resin: A unique bifunctional catalyst for the continuous catalytic hydrogenation of organic compounds in supercritical carbon dioxide
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1% Palladium-doped acidic resin (Amberlyst 15; styrene-divinylbenzene matrix with sulfonic acid groups) is shown to be a highly active catalyst for the continuous catalytic hydrogenation of C=C bonds in supercritical carbon dioxide (scCO2) without affecting C=O bonds. This 1% Pd/Amberlyst-15 catalyst promotes the industrially important selective formation of 2-ethylhexanal from crotonaldehyde in a one-pot pathway involving hydrogenation and aldol condensation witha number of merits. The selectivity behavior of 1% Pd/Amberlyst-15 is strikingly different compared to that of 1% Pd/C and 1% Pd/Al2O3 due to its prominent bifunctional nature based on sulfonic acid groups adjacent to metallic Pd sites. Hybrid [Pdn-H]+ sites are suggested to act as bothmet al and acid sites promoting the bifunctional catalysis.
- Seki, Tsunetake,Grunwaldt, Jan-Dierk,Van Vegten, Niels,Baiker, Alfons
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body text
p. 691 - 705
(2009/04/12)
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- N,N-dialkylpolyhydroxyalkylamines
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N,N-Dialkylpolyhydroxyalkylamines may be made by the reductive alkylation of an N-alkylpolyhydroxyalkylamine with an aldehyde or ketone, or with an equivalent compound, in the presence of a transition metal catalyst and hydrogen. The reaction is performed in a reaction solvent that contains at least 30 wt% of an organic solvent. The use of a sufficiently high proportion of an appropriate organic solvent in the reaction mixture reduces the amount of water present in the reaction mixture, and provides rapid reaction rates and high yields of the desired product. The N,N-dialkylpolyhydroxyalkylamines may be used in a wide variety of applications.
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Page/Page column 14-15
(2008/06/13)
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