- Rational design of efficient steric catalyst for isomerization of 2-methyl-3-butenenitrile
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The catalytic isomerization of 2-methyl-3-butenenitrile (2M3BN), a model reaction in the DuPont process, has been performed using NiL4 (L=tri-O-p-tolyl phosphite) as a catalyst. The lowered catalytic activity in the isomerization with coexistence of 2-pentenenitrile (2PN) and 2-methyl-2-butenenitrile (2M2BN) indicates that both 2PN and 2M2BN are the catalyst inhibitors, and the quantitative relationship between the conversion of 2M3BN and the content of 2M2BN and 2PN is provided. DFT calculation results suggest that the inhibition effect is attributed to the generation of dead-end intermediates (2PN)NiL2 and (2M2BN)NiL2, both of which take nickel atom out of the catalytic cycle in the isomerization process. To suppress the inhibition effect, new catalytic intermediates are rationally designed based on their computational %Vbur. An efficient method that adding extra ligand 1, 5-bis(diphenylphosphino)pentane (dppp5) to the NiL4 catalyst is selected experimentally. Compared to the results obtained with NiL4 as catalyst, the (dppp5)NiL2 increases the conversion of 2M3BN from 74.5 % to 93.4 % at 3 h of reaction and provides a high selectivity to 3PN (> 98 %) at optimal conditions.
- Han, Minghan,Liu, Kaikai,Wang, Tiefeng
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- PROCESS FOR MAKING AND REFINING 3-PENTENENITRILE, AND FOR REFINING 2-METHYL-3-BUTENENITRILE
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The invention provides an integrated, continuous process for the production of 3-pentenenitrile, the refining of 3-pentenenitrile, and the refining of 2-methyl-3-butenenitrile, the process comprising: (a) contacting, in a reaction zone, a hydrogen cyanide-containing feed, a butadiene-containing feed, and a catalyst composition, wherein the catalyst composition comprises a zero-valent nickel and at least one bidentate phosphorus-containing ligand selected from the group consisting of a phosphite, a phosphonite, a phosphinite, a phosphine, a mixed phosphorus-containing ligand, and combination thereof; (b) maintaining a residence time in the reaction zone sufficient to convert about 95% or more of the hydrogen cyanide and to produce a reaction mixture comprising 3-pentenenitrile and 2-methyl-3-butenenitrile, wherein the 2-methyl-3-butenenitrile concentration is maintained below about 15 weight percent of the total mass of the reaction mixture; (c) distilling the reaction mixture to obtain a first stream comprising 1,3-butadiene, a second stream comprising 3-pentenenitrile, 2-methyl-3-butenenitrile, (Z)-2-methyl-2-butenenitrile, and optionally 1,3-butadiene, and a third stream comprising the catalyst composition; (d) distilling the second stream to obtain a fourth stream comprising 1,3-butadiene, a fifth stream comprising 2-methyl-3-butenenitrile, (Z)-2-methyl-2-butenenitrile, and optionally 1,3-butadiene, and a sixth stream comprising 3-pentenenitrile; and (e) distilling the fifth stream to obtain a seventh stream comprising 1,3-butadiene, an eighth stream comprising (Z)-2-methyl-2-butenenitrile, and a ninth stream comprising 2-methyl-3-butenenitrile.
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Page/Page column 24-25
(2009/07/25)
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- Solvent effects and activation parameters in the competitive cleavage of C-CN and C-H bonds in 2-methyl-3-butenenitrile using [(dippe)NiH]2
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The reaction of [(dippe)NiH]2 with 2-methyl-3-butenenitrile (2M3BN) in solvents spanning a wide range of polarities shows significant differences in the ratio of C-H and C-CN activated products. C-H cleavage is favored in polar solvents, whereas C-C cleavage is favored in nonpolar solvents. This variation is attributed to the differential solvation of the transition states, which was further supported through the use of sterically bulky solvents and weakly coordinating solvents. Variation of the temperature of reaction of [(dippe)NiH]2 with 2M3BN in decane and N,N-dimethylformamide (DMF) allowed for the calculation of Eyring activation parameters for the C-CN activation and C-H activation mechanisms. The activation parameters for the C-H activation pathway were ΔH? = 11.4 ± 5.3 kcal/mol and ΔS? = -45 ± 15 e.u., compared with ΔH? = 17.3 ± 2.6 kcal/mol and ΔS ? = -29 ± 7 e.u. for the C-CN activation pathway. These parameters indicate that C-H activation is favored enthalpically, but not entropically, over C-C activation, implying a more ordered transition state for the former.
- Swartz, Brett D.,Reinartz, Nicole M.,Brennessel, William W.,Garcia, Juventino J.,Jones, William D.
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experimental part
p. 8548 - 8554
(2009/02/03)
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- Practical synthesis of 3-amino-4,5-dimethylisoxazole from 2-methyl-2-butenenitrile and acetohydroxamic acid
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3-Amino-4,5-dimethylisoxazole was prepared from technicalgrade 2-methyl-2-butenenitrile and acetohydroxamic acid in a 62% overall yield on a multimole scale. The key features of this synthesis are (1) DBU treatment of the technical-grade nitrile mixture to provide a starting material of acceptable purity and (2) use of acetohydroxamic acid as an N-protected hydroxylamine equivalent. This operationally simple method provides the title compound in reasonable overall yield and free of contamination from the isomeric 5-amino-3,4-dimethylisoxazole.
- Tellew, John E.,Leith, Leslie,Mathur, Arvind
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p. 275 - 277
(2012/12/26)
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- METHOD FOR PRODUCING 3-PENTENENITRILE
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The invention relates to a method for producing 3-pentenenitrile, said method being characterised by the following steps: (a) 1,3-butadiene is reacted with hydrogen cyanide on at least one catalyst to obtain a flow (1) containing 3-pentenenitrile, 2-methyl-3-butenenitrile, the at least one catalyst, and 1,3-butadiene; (b) the flow (1) is distilled in a column to obtain a top product flow (2) rich in 1,3-butadiene, and a bottom product flow (3) that is poor in 1,3-butadiene and contains 3-pentenenitrile, the at least one catalyst, and 2-methyl-3-butenenitrile; (c) the flow (3) is distilled in a column to obtain a top product flow (4) containing 1,3-butadiene, a flow (5) in a side-tap of the column, containing 3-pentenenitrile and 2-methyl-3-butenenitrile, and a bottom product flow (6) containing the at least one catalyst; and (d) the flow (5) is distilled to obtain a top product flow (7) containing 2-methyl-3-butenenitrile, and a bottom product flow (8) containing 3-pentenenitrile.
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Page/Page column 35-38; sheet 5
(2008/06/13)
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- PRODUCTION OF 3-PENTENENITRILE FROM 1,3-BUTADIENE
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The invention relates to a method for producing 3-pentenenitrile by means of the hydrocyanation of 1,3-butadiene, whereby 1,3-butadiene is reacted with hydrogen cyanide in the presence of at least one catalyst, and the resulting flow is purified by distillation, the bottom temperature not exceeding 140 °C during the distillation.
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Page/Page column 25-29; sheet 2
(2008/06/13)
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- METHOD FOR PRODUCING LINEAR PENTENENITRILE
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The invention relates to a method for producing 3-pentenenitrile, characterised by the following steps: (a) isomerisation of an educt stream containing 2-methyl-3-butenenitrile on at least one dissolved or dispersed isomerisation catalyst to form a stream (1), which contains the isomerisation catalyst(s), 2-methyl-3-butenenitrile, 3-pentenenitrile and (Z)-2-methyl-2-butenenitrile; (b) distillation of the stream (1) to obtain a stream (2) as the overhead product, which contains 2-methyl-3-butenenitrile, 3-pentenenitrile and (Z)-2-methyl-2-butenenitrile and a stream (3) as the bottom product, which contains the isomerisation catalyst(s); (c) distillation of the stream (2) to obtain a stream (4) as the overhead product, which is enriched with (Z)-2-methyl-2-butenenitrile in comparison to stream (2), (in relation to the sum of all pentenenitriles in stream (2)) and a stream (5) as the bottom product, which is enriched with 3-pentenenitrile and 2-methyl-3-butenenitrile in comparison to stream (2), (in relation to the sum of all pentenenitriles in stream (2); (d) distillation of stream (5) to obtain a stream (6) as the bottom product, which contains 3-pentenenitrile and a stream (7) as the head product, which contains 2-methyl-3-butenenitrile.
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Page/Page column 72-76; sheet 2
(2008/06/13)
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- Sterically demanding diphosphonite ligands - Synthesis and application in nickel-catalyzed isomerization of 2-methyl-3-butenenitrile
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The synthesis of a novel class of sterically demanding diphosphonites 1-8, based on rigid backbones, is described. The starting materials are all commercially available and the methodology allows for a modular approach. All ligands have been fully characterized, including an X-ray crystal structure for compound 1, 4,5-bis{di[(2-terr-butyl)phenyl]phosphonito}-9,9-dimethylxanthene. The coordination of these diphosphonite ligands towards Ni(II) and Ni(0) precursors is investigated, both by NMR spectroscopy as well as X-ray crystallography and compared with the behaviour of diphosphine ligands such as Xantphos. The molecular structure for complex 9, trans-[NiBr2(1)] is described in detail. The nickel-catalyzed isomerization of 2-methyl-3- butenenitrile to 3-pentenenitrile is studied, a relevant step in the industrially important hydrocyanation of butadiene (the DuPont adiponitrile process). Good activities and selectivities to the desired 3-pentenenitrile are obtained in this reversible C-C bond activation reaction.
- Van Der Vlugt, Jarl Ivar,Hewat, Alison C.,Neto, Samuel,Sablong, Rafael,Mills, Allison M.,Lutz, Martin,Spek, Anthony L.,Mueller, Christian,Vogt, Dieter
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p. 993 - 1003
(2007/10/03)
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- PREPARATION OF (E)- AND (Z)-2-METHYL-2-BUTENOIC ACIDS
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A method has been developed to prepare (E)- and (Z)-2-methyl-2-butenoic acids (2M2BA) from a mixture of (E,Z)-2-methyl-2-butenenitriles (2M2BN) by the regioselective hydrolysis of (E)-2M2BN to (E)-2-methyl-2-butenoic acid (2M2BA) using enzyme catalysts having either a nitrilase activity or a combination of nitrile hydratase and amidase activities. The method provides high yields without significant conversion of (Z)-2M2BN to (Z)-2M2BA. The regioselective hydrolysis of (E)-2M2BN to (E)-2M2BA makes possible the facile separation of (E)-2M2BA from (Z)-2M2BN or (Z)-2-methyl-2-butenamide (2M2BAm), and the subsequent conversion of (Z)-2M2BN or (Z)-2M2BAm to (Z)-2M2BA.
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- Simple and efficient preparation of [10,20-13C2]- and [10-CH3,13-13C2]-10-methylretinal: Introduction of substituents at the 2-position of 2,3-unsaturated nitriles
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In this paper, we present the synthesis of [10,20-13C2]-10-methylretinal and [10-CH3,13-13C2]-10-methylretinal, two doubly 13C-labeled chemically modified retinals that have been recently used to study the structural and functional details behind the photocascade of bovine rhodopsin (Verdegem et al. Biochemistry 1999, 38, 11316; de Lange et al. Biochemistry 1998, 37, 1411). To obtain both doubly 13C-labeled compounds, we developed a novel synthetic method to directly and regiospecifically introduce a methyl substituent on the 2-position of 3-methyl-5-(2′,6′,6′-trimethyl-1′ -cyclohexen-1′-yl)-2,4-pentadienenitrile. Encouraged by these results, we investigated the scope of this novel reaction by developing a general method for the introduction of a variety of substituents to the 2-position of 3-methyl-2,3-unsaturated nitriles, paving the way for simple and efficient synthesis of a wide variety of 10-, 14-, and 10,14-substituted chemically modified retinals, and other biologically important compounds.
- Verdegem,Monnee,Lugtenburg
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p. 1269 - 1282
(2007/10/03)
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- The Cyanation of Vinyl Halides with Alkali Cyanides Catalyzed by Nickel(0)-Phosphine Complexes Generated In Situ: Synthetic and Stereochemical Aspects
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The cyanation of β-bromostyrenes catalyzed by Ni(PPh3)n, which was generated in situ from NiBr2(PPh3)2-Zn-PPh3 (Ni:Zn:P=1:3:2 molar ratio), was at first examined with various MCN (M=K, Na)-dipolar aprotic solvent systems by several procedures.The presence of excess cyanide ion inhibited the reaction.However, when the KCN-DMF system with some intermediate cyanide solubility was used, the nitriles were obtained in high yields and high stereoselectivity at 50 deg C by almost all of the procedures attempted.On the contrary, the KCN-HMPA and KCN-MeCN systems with cyanide solubilities accelerated the coupling of the halides to inhibit the cyanation, and in general the NaCN-DMF and NaCN-HMPA systems with high cyanide solubilities needed to reduce Ni(II) before adding MCN in order to make the catalytic reaction start.Vinyl halides such as 1- and 2-halo (Cl, Br)-1-alkenes, 2-bromo-2-butenes, 3-bromo-3-hexenes, and 1-chlorocyclohexene were also cyanated using suitable procedures and MCN-solvent systems to give the corresponding nitriles in high yields and fair-to-good stereoselectivities.However, with (Z)-2-ethoxy-1-bromoethene the (E)-nitrile, though its selectivity markedly varied with the reaction temperature, was obtained as the main product.The cyanation of ethyl (Z)-β-bromoacrylate and ethyl α-bromoacrylate was unsuccessful due to polymerization.
- Sakakibara, Yasumasa,Enami, Hiroji,Ogawa, Hiroshi,Fujimoto, Shinpei,Kato, Hiroyuki,et al.
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p. 3137 - 3144
(2007/10/03)
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- Addition of aldehydes to organic compounds having a carbon-hydrogen bond activated by a nitro or nitrile group
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Low valent transition metal complexes containing small cone angle phosphine or arsine ligands efficiently catalyze addition of aldehydes to compounds or groups having a C--H bond activated by a nitro or nitrile group, to provide nitroalcohols or cyanohydrins, respectively.
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- Stereoselective Cyanation of Vinyl Halides Catalyzed by Tetracyanocobaltate(I)
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Tetracyanocobaltate(I), 3-, which is formed in an aqueous alkaline solution under a hydrogen atmosphere, catalyzes the cyanation of vinyl halides to form 2-alkenenitriles.The reaction is stereoselective, forming nitriles with retention of configuration, except for (Z)-2-bromobut-2-ene, which forms a mixture of nearly equimolar isomeric nitriles.Reactivity is dependent on the CN:Co ratio and is highest when the ratio is slightly lower than 5:1.Presence of excess cyanide ion inhibits the reaction, but a dropwise addition of the KCN solution to maintain CN:Co3-, were detected as intermediates by 1H and 13C NMR spectroscopy, indicating that the reaction proceeds stepwise.In the first step, the ? complex is formed by the oxidative addition of a vinyl halide to 3- via a radical nonchain process; in this step stereoselectivity is determined.In the second step, which is rate determining, a 2-alkenenitrile is formed by the reductive coupling of the vinyl and cyano ligands, regenerating 3-.Clear NMR evidence has been obtained for the formation of 3-, where the olefin is (E)- or (Z)-cinnamonitrile.A high degree of electron transfer from 3- to olefin was indicated by the large upfield shifts of the olefinic carbon atom resonances by coordination.
- Funabiki, Takuzo,Hosomi, Hiroaki,Yoshida, Satohiro,Tarama, Kimio
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p. 1560 - 1568
(2007/10/02)
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