Selective hydrogenation of citral over amorphous NiB and CoB nano-catalysts

Chen, Yin‐Zu; Liaw, Biing‐Jye; Chiang, Shu‐Jen

doi:10.1016/j.apcata.2005.01.023

Cited by 78 publications

(54 citation statements)

References 22 publications

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“…[19] As a result of the presence of multiple C = C and C = O bonds, the asymmetric reduction of citral (1 a, Table 1) in a chemo-, regio-, and stereoselective fashion is a challenging task. [2,20] Both OPR1 and OPR3 quickly reduced the conjugated C=C-bond in a highly chemo-, regio-, and stereoseScheme 1. Asymmetric bioreduction of activated alkenes bearing an activating electron-withdrawing group (EWG) by enoate reductases.…”

mentioning

confidence: 99%

Asymmetric Bioreduction of Activated Alkenes Using Cloned 12‐Oxophytodienoate Reductase Isoenzymes OPR‐1 and OPR‐3 from Lycopersicon esculentum (Tomato): A Striking Change of Stereoselectivity

et al. 2007

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The asymmetric reduction of C=C bonds goes in hand with the creation of up to two chiral centers and is thus one of the most widely employed strategies for the synthesis of chiral compounds. Whereas cis hydrogenation using homogeneous catalysts based on (transition) metals has been developed to a high standard, [1] stereocomplementary trans reduction is still at the stage of development. [2,3] The biocatalytic equivalent of this reaction is catalyzed by enoate reductases [EC 1.3.1.x], [4,5] commonly denoted as the "old yellow enzyme" family.[6] These common enzymes act through transfer of a hydride ion, derived from a flavin cofactor (FMNH 2 ), onto the b-carbon atom of an a,bunsaturated carbonyl compound, while a proton, derived from the solvent, adds from the opposite side onto the acarbon atom. As a consequence of this mechanism, the hydrogenation occurs in a trans-specific fashion. The catalytic cycle is completed by the reduction of FMN at the expense of NAD(P)H, which is regenerated by an additional redox reaction (Scheme 1). Although the mode of action of these enzymes has been elucidated in great detail, their application in preparative-scale biotransformations has been hampered for several reasons: although the best-studied enzymes from this group, which were isolated from strictly anaerobic bacteria such as Proteus and Clostridium spp., [7] were shown to be highly stereoselective, the sensitivity of these proteins towards traces of molecular oxygen prevented their practical application. As a consequence, whole-cell biotransformations using aerobic microorganisms, most prominently bakers yeast, [8] dominated the field. Although the stereoselectivities achieved were often excellent, the chemoselectivity of wholecell bioreductions with respect to the reduction of C = C against C=O bonds was notoriously plagued by the competing reduction of the carbonyl group that was catalyzed by alcohol dehydrogenases. [9,10] Since enoate reductases and alcohol dehydrogenases depend on the same nicotinamide cofactor, redox decoupling of both enzyme activities is not possible.Isolated and/or cloned enoate reductases are required in sufficient amounts, together with a suitable recycling system for the nicotinamide cofactor, to make this biotransformation practically feasible. Only recently, the first successful attempts in the chemo-and stereoselective reduction of conjugated enones were reported by using cloned old yellow enzymes from Saccharomyces carlsbergensis [11] and bakers yeast. [12] Since enoate reductases have been shown to possess a much broader substrate spectrum than their name would suggest, [13] we initiated a search for a candidate that possessed a broad substrate specificity but showed high stereoselectivity towards a wide range of C = C bonds bearing an electronwithdrawing activating group. In this context, we came across 12-oxophytodienoate reductase (OPR) which occurs in several isoforms in plants. [14] Whereas isoenzyme OPR3 is responsible for the reduction of (9S,13S)-12-oxophytodienoate to the corre...

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mentioning

confidence: 99%

Asymmetric Bioreduction of Activated Alkenes Using Cloned 12‐Oxophytodienoate Reductase Isoenzymes OPR‐1 and OPR‐3 from Lycopersicon esculentum (Tomato): A Striking Change of Stereoselectivity

et al. 2007

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“…Dragieva et al focused on developing amorphous alloys as electrode or catalytic oxidation materials [38][39][40][41][42][43], while Chen and coworkers prepared MPB alloy nanoparticle catalysts for various selective hydrogenation reactions [44][45][46][47][48][49][50]. Amorphous alloy nanoparticulate catalysts have been widely studied by different research groups in China [51][52][53][54][55][56][57][58][59][60]. Among them, our group has attempted to develop NiB and NiP industrial amorphous alloy catalysts in various catalytic hydrogenation reactions [61][62][63][64][65][66][67][68][69][70][71][72].…”

Section: History Of Amorphous Alloy Catalystmentioning

confidence: 99%

Advances in chemical synthesis and application of metal-metalloid amorphous alloy nanoparticulate catalysts

Zhang

et al. 2007

Front. Chem. Eng. China

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This paper reviews the advances in the chemical synthesis and application of metal-metalloid amorphous alloy nanoparticles consisting of transition metal (M) and metalloid elements (B, P). After a brief introduction on the history of amorphous alloy catalysts, the paper focuses on the properties and characterization of amorphous alloy catalysts, and recent developments in the solution-phase synthesis of amorphous alloy nanoparticles. This paper further outlines the applications of amorphous alloys, with special emphasis on the problems and strategies for the application of amorphous alloy nanoparticles in catalytic reactions. History of amorphous alloy catalystAmorphous alloys have been extensively investigated internationally over the last 50 years largely spurred by their unique electronic, magnetic and surface properties and their increasing utility in a broad range of applications [1,2]. The amorphous alloy nanoparticles have gained increasing attention as novel catalytic materials since 1980, with the unique isotropic structure and high concentration of coordinatively unsaturated sites leading to catalytic activity and selectivity superior to their crystalline counterparts [3]. Especially, amorphous alloys chemically reduced by borohydride (BH 4 − ) and hypophosphite (H 2 PO 2 − ) have nanosized morphology and consequently higher surface area and activity than those prepared by the quenching method [4][5][6][7][8]. It has been regarded that the amorphous alloy catalyst can be a potential alternative to Raney nickel or noble metal catalyst in catalytic hydrogenation. Raney nickel has shown many serious disadvantages, such as short lifetimes due to poor sulfur resistance and environmental pollution caused by alkaline leaching during preparation. In contrast, the amorphous alloy nanoparticulate catalysts are inexpensive, environmentally benign, and effective catalytic materials.For the chemical synthesis of metal-metalloid amorphous alloy catalysts, Brown et al. and Paul et al. found that the NiB particles reduced by sodium borohydride in water or ethanol solution showed excellent catalytic activity and selectivity in many hydrogenation reactions [9][10][11][12][13][14][15]. After that, and Chen et al. [21][22][23][24] studied the mechanism of borohydride reduction and the relation between properties and preparation conditions. On the other hand, Deng and coworkers have been interested in studying the properties of amorphous alloy particles and the application of metal boron (MB) and metal phosphorus (MP) amorphous alloys for catalytic hydrogenation [25-37]. Dragieva et al. focused on developing amorphous alloys as electrode or catalytic oxidation materials [38-43], while Chen and coworkers prepared MPB alloy nanoparticle catalysts for various selective hydrogenation reactions [44-50]. Amorphous alloy nanoparticulate catalysts have been widely studied by different research groups in China [51-60]. Among them, our group has attempted to develop NiB and NiP industrial amorphous alloy catalysts in various catalyt...

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“…It has been reported that NiB and CoB amorphous catalysts exhibited high activity and selective in the selective hydrogenation of citral. Liaw et al [19] revealed that supported NiB-SiO 2 also showed high activity for citral hydrogenation at low temperature [20].…”

Section: Introductionmentioning

confidence: 97%

“…On the other hand, metal-metalloid amorphous catalysts like Ni-B, Cu-B and Co-B, etc., which possess the structures with long-range disorder and short-range order, have recently attracted much attention due to their superior activity and selectivity in some catalytic hydrogenation processes [19][20][21][22]. It has been reported that NiB and CoB amorphous catalysts exhibited high activity and selective in the selective hydrogenation of citral.…”

Section: Introductionmentioning

confidence: 99%

Catalytic Behaviors of Amorphous Co-B Catalysts in Hydroformylation of 1-Octene

Peng

2009

Catal Lett

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An amorphous Co-B catalyst was prepared by chemical reduction method and characterized by isothermal N 2 adsorption/desorption, XRD, ICP-AES and HR-TEM. The catalytic activity of the Co-B catalyst in the hydroformylation of 1-octene was evaluated in a 100 mL stainless autoclave. Fresh amorphous Co-B catalyst showed a relatively high activity in the hydroformylation of 1-octene. The thermal stability of fresh Co-B catalyst was also examined. When fresh Co-B catalyst was thermally treated in N 2 or H 2 atmosphere at 200-500°C for 2 h, the specific surface area and the catalytic activity of the Co-B catalyst decreased. When Co-B was supported on SiO 2 , the activity of the catalyst increased obviously. Compared with conventional supported Co/SiO 2 catalyst, Co-B/SiO 2 showed much higher activity than Co/SiO 2 . The influences of solvents and reaction conditions on the catalytic activity of the amorphous Co-B catalyst were also studied. The recycle test of the amorphous Co-B catalyst was done.

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Selective hydrogenation of citral over amorphous NiB and CoB nano-catalysts

Cited by 78 publications

References 22 publications

Asymmetric Bioreduction of Activated Alkenes Using Cloned 12‐Oxophytodienoate Reductase Isoenzymes OPR‐1 and OPR‐3 from Lycopersicon esculentum (Tomato): A Striking Change of Stereoselectivity

Asymmetric Bioreduction of Activated Alkenes Using Cloned 12‐Oxophytodienoate Reductase Isoenzymes OPR‐1 and OPR‐3 from Lycopersicon esculentum (Tomato): A Striking Change of Stereoselectivity

Advances in chemical synthesis and application of metal-metalloid amorphous alloy nanoparticulate catalysts

Catalytic Behaviors of Amorphous Co-B Catalysts in Hydroformylation of 1-Octene

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