- Theoretical and experimental study of the nickel-catalyzed isomerization of 2-Methyl-3-butenenitrile and the effect of a Lewis acid
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A combined experimental and theoretical study was conducted to investigate the isomerization of 2-methyl-3-butenenitrile (2M3BN) to 3-pentenenitrile (3PN) and to 2-methyl-2-butenenitrile (2M2BN) catalyzed by nickel diphosphine complexes. Ni(1,4-bis(diphenylphosphino)butane) (dppb) was identified as the most reactive catalyst among the complexes that we examined experimentally. Quantum mechanics (density functional theory) was then used to study the two isomerization mechanisms catalyzed by this complex. We find that for the 2M3BN?→?3PN isomerization, the reaction is initiated with [Formula presented] bond cleavage, followed by an allyl direct rotation and [Formula presented] bond reformation. For the 2M3BN?→?2M2BN isomerization, the most energetically favorable pathway begins with [Formula presented] bond activation, followed by a π-σ-σ-π allyl rearrangement and [Formula presented] bond reformation. Our proposed mechanism for the 2M3BN?→?2M2BN isomerization is slightly different (yet energetically more favorable) than that described in previous studies, where it has been suggested that 2M2BN is obtained through a π-σ-σ allyl rearrangement rather than a π-σ-σ-π type rearrangement. Additionally, we investigated the effect of Lewis acids in the 2M3BN?→?3PN isomerization, which has been shown in most experiments to attenuate the reaction. Notably, our calculations indicated that ZnCl2, which is used as a model Lewis acid, actually reduces the barriers for all elementary steps. However, the effective kinetic barrier for the isomerization increases from 23.7 (without ZnCl2) to 24.0?kcal/mol because of the formation of a very stable Ni(π-allyl) ([Formula presented]2) intermediate, causing a decrease in the reaction rate. This theoretical result was further confirmed by our own experiments.
- Liu, Kun,Liu, Kai-Kai,Cheng, Mu-Jeng,Han, Ming-Han
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Read Online
- A synthesis section of the mixed solution directly isomerization of 2-methyl-2-crotonization method
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The invention discloses a method for synthesizing 2-methyl-2-butenenitrile through direct isomerization of alkene-nitrile mixed liquid. The method is characterized in that isomerization reaction occurs by adding calcium-containing inorganic base to the alkene-nitrile mixed liquid containing 2-methyl-3-butenenitrile and 3-pentenenitrile so as to generate a product containing the 2-methyl-2-butenenitrile. According to the method, the process of purifying the 2M3BN through reduced pressure rectification is omitted, the calcium-containing inorganic base is used as a catalyst and directly isomerizes the alkene-nitrile mixed liquid containing the 2M3BN and 3PN into the 2M2BN, and the reaction conversion rate and the selectivity are greater than 95% respectively. Compared with a conventional method, the method has the advantages that the rectification separation process of the alkene-nitrile mixed liquid is omitted, so that the whole process route is shortened, the technological process is simplified, the equipment cost and the production cost are reduced, the calcium-containing inorganic base is used as the catalyst, low in price and easy to obtain and can be recycled, and industrial wastewater, waste gases and residues are basically not generated in the whole technological process.
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Paragraph 0018-0019
(2017/02/09)
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- Unlocking Mizoroki–Heck-Type Reactions of Aryl Cyanides Using Transfer Hydrocyanation as a Turnover-Enabling Step
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A new transfer hydrofunctionalization strategy to turnover H-MII-X complexes has enabled both intra- and intermolecular Mizoroki–Heck (MH)-type reactions of aryl cyanides that are challenging to realize under traditional, basic conditions. Initially, a cascade carbonickelation/MH reaction of 2-cyanostyrenes was achieved using a key alkyne transfer hydrocyanation step. Mechanistic experiments supported the proposed catalytic cycle, including the turnover-enabling transfer hydrocyanation step. The reactivity was then extended to the intermolecular MH reaction of benzonitriles and styrenes.
- Fang, Xianjie,Yu, Peng,Prina Cerai, Gabriele,Morandi, Bill
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supporting information
p. 15629 - 15633
(2016/10/24)
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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 92-94
(2008/06/13)
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- Method for making nitrile compounds from ethylenically unsaturated compounds
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The invention concerns a method for hydrocyanation of ethylenically unsaturated organic compounds comprising at least a nitrile function. The invention provides a method for hydrocyanation of an ethylenically unsaturated hydrocarbon compound by reacting in liquid medium the hydrogen cyanide in the presence of a catalyst comprising a metal element selected among transition metals and an organophosphorous ligand, characterised in that the organophosphorous ligand is a furylphosphine. The invention is in particular useful for synthesizing adiponitrile from butadiene.
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- Regioselective biocatalytic hydrolysis of (E,Z)-2-methyl-2-butenenitrile for production of (E)-2-methyl-2-butenoic acid
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Acidovorax facilis 72W nitrilase catalyzed the regioselective hydrolysis of (E,Z)-2-methyl-2-butenenitrile, producing only (E)-2-methyl-2-butenoic acid with no detectable conversion of (Z)-2-methyl-2-butenenitrile. (E)-2-Methyl-2-butenoic acid, produced in aqueous solution as the ammonium salt, was readily separated from (Z)-2-methyl-2-butenenitrile, and isolated in high yield and purity. The combination of nitrile hydratase and amidase activities of several Comamonas testosteroni strains were also highly regioselective for the production of (E)-2-methyl-2-butenoic acid from (E,Z)-2-methyl-2- butenenitrile.
- Hann, Eugenia C.,Sigmund, Amy E.,Fager, Susan K.,Cooling, Frederick B.,Gavagan, John E.,Bramucci, Michael G.,Chauhan, Sarita,Payne, Mark S.,DiCosimo, Robert
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p. 577 - 581
(2007/10/03)
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- ELECTROOXIDATIVE DESULFENYLATION OF MICHAEL-TYPE THIOL ADDUCTS OF α,β-UNSATURATED ESTERS, KETONES, AND NITRILES
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Michael adducts of ethanethiol with α,β-unsaturated esters ketones,and nitriles are conveniently desulfenylated under neutral conditions by an electrooxidation involving bromonium ion mediation.
- Kimura, Makoto,Matsubara, Shinichi,Sawaki, Yasuhiko,Iwamura, Hiizu
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p. 4177 - 4178
(2007/10/02)
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- Production of Acrylonitrile and Other Unsaturated Nitriles from Alkenes and Alkynes
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Passage of unsaturated organic molecules trough a 13.56-MHz radio-frequency discharge, in the presence of cyanogen, results in the formation of unsaturated nitriles.Acrylonitrile was the major product from ethylene, propylene, acrolein, methyl vinyl ketone, or 1,1,1-trifluoropropylene. 1-Butene, 2-butene, and isobutylene gave mixtures of nitrile products with the CN situated at vinylic or allylic positions. 2-Butyne gave 1-cyanopropyne.Other compounds gave only low yields of nitriles and considerable polymer.The effects of power, pressure, flow rate, and ratios of reactants on the yields of acrylonitrile from propylene and cyanogen were studied.A typical power yield of acrylonitrile was 30 g kW-1 h-1.Maximum material yields of nitrile products were obtained at intermediate powers and pressures.The products are consistent with a reaction scheme involving attack of initially formed cyano radicals on the organic substrate.This step forms activated radical intermediates, which decay through elimination of an atom or group.The atom or group which is most weakly bound is preferentially lost.
- Henis, Neil B.,Miller, Larry L.
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p. 2526 - 2529
(2007/10/02)
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