超臨界流体-イオン性液体二相システムにおけるアルケンの連続流水酸化
Paul B Webb1, Murielle F Sellin, Thulani E Kunene
1School of Chemistry, University of St. Andrews, St. Andrews, Fife, KY16 9ST, Scotland.
Journal of the American Chemical Society
|December 11, 2003
まとめ
本研究では,超臨界のCO2とイオン性液体を使用した連続流水酸化プロセスが紹介されています. この方法は,効率的に触媒と溶媒から製品を分離し,高い活性と安定性を達成します.
科学分野:
- 化学工学は化学工学というものです.
- カタリシス カタリシス カタリシス
- グリーン・ケミストリー (Green Chemistry)
背景:
- ハイドロフォームミレーションはアルデヒドを生成するための重要な工業プロセスです.
- 伝統的な方法は,しばしば厳しい条件と困難な触媒分離を伴う.
- 連続フローシステムは,効率と安全性の点で利点を提供します.
研究 の 目的:
- 低揮発性アルケンの連続流水成型プロセスを開発する.
- 超臨界のCO2とイオン性液体を使用して,反応と分離の強化を調査する.
- 高活性と安定性を確保するために,触媒システムを最適化します.
主な方法:
- 絶え間ない流れの原子炉システムを使用した.
- イオン性液体を触媒溶媒として使用した.
- 反応物質と産物の輸送媒体として超臨界CO2を使用した.
- 硫化ホスフィンを含む様々なロジウムベースの触媒を研究した.
主要な成果:
- 高い触媒回転周波数 (最大500h~-1) を達成しました.
- 溶媒や触媒のない効率的な製品分離が実証されています.
- 特定された特定のイオン性液体 (1-アルキル-3-メチリミダゾリウムビス ((C8+アルキル鎖を持つトリフローロメタンスルフォニル) アミド) を最適の性能のために.
- 最適な条件下で,低ロジウム浸出 (0.012ppmまで) が観察されています.
- 触媒の分解なしに数週間の継続的な動作を示した.
結論:
- 超臨界流体-イオン液体 (SCF-IL) システムは,継続的な水酸化処理のための実行可能で効率的な方法です.
- イオン液体と触媒リガンドの慎重な選択は,プロセスの成功に不可欠です.
- このプロセスは,製品の純度および触媒のリサイクル性という点で大きな利点を提供します.
関連する概念動画
02:41Formation of Halohydrin from Alkenes
An alkene, such as propene, reacts with bromine in the presence of water to yield a halohydrin. Halohydrins contain a halogen and a hydroxyl group attached to adjacent carbons. When the halogen is bromine, it is called a bromohydrin, while a chlorohydrin has chlorine as the halogen.
03:08Hydroboration-Oxidation of Alkenes
In addition to the oxymercuration–demercuration method, which converts the alkenes to alcohols with Markovnikov orientation, a complementary hydroboration-oxidation method yields the anti-Markovnikov product. The hydroboration reaction, discovered in 1959 by H.C. Brown, involves the addition of a B–H bond of borane to an alkene giving an organoborane intermediate. The oxidation of this intermediate with basic hydrogen peroxide forms an alcohol.
02:35Electrophilic Addition to Alkynes: Hydrohalogenation
Electrophilic addition of hydrogen halides, HX (X = Cl, Br or I) to alkenes forms alkyl halides as per Markovnikov's rule, where the hydrogen gets added to the less substituted carbon of the double bond. Hydrohalogenation of alkynes takes place in a similar manner, with the first addition of HX forming a vinyl halide and the second giving a geminal dihalide.
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
Introduction
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
02:24Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation
Introduction
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
01:26Radical Substitution: Hydrogenolysis of Alkyl Halides with Tributyltin Hydride
Radical substitution reactions can be used to remove functional groups from molecules. The hydrogenolysis of alkyl halides is one such reaction, where the weak Sn–H bond in tributyltin hydride reacts with alkyl halides to form alkanes. Here, the reagent Bu3SnH yields tributyltin halide as a byproduct.
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation reactions,...
The bonds formed in this reaction are stronger than the bonds broken, making it energetically favorable. The reaction follows a radical chain mechanism similar to radical halogenation reactions,...