酸化剤依存的なモリブデン(VI)テトラゾラート錯体の均一系からオレフィンエポキシ化のための自己分離型触媒への転換
Martinique S Nunes1, Diana M Gomes1, Patrícia Neves1
1CICECO - Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, Campus Universitário de Santiago, Aveiro 3810-193, Portugal.
まとめ
研究者らは、効率的なエポキシド製造のための新しい自己分離型モリブデン触媒を開発しました。このリサイクル可能な触媒は、穏やかな条件下で高い選択性と転化率を達成し、均一系活性と不均一系回収を組み合わせています。
科学分野:
- 触媒化学
- 材料科学
- 有機化学
背景:
- 均一系モリブデン触媒は、バルクエポキシド製造のために確立されています。
- 複雑なエポキシドのためのリサイクル可能な触媒の開発は、依然として大きな課題です。
研究 の 目的:
- 効率的でリサイクル可能なエポキシド合成のための自己分離型モリブデン触媒を設計すること。
- 触媒回収のための反応誘起沈殿を調査すること。
主な方法:
- モリブデン(VI)テトラゾラート錯体の合成と結晶学的特性評価。
- 触媒分離のための反応誘起沈殿の利用。
- 様々な基質と酸化剤(tert-ブチルヒドロペルオキシドおよび過酸化水素)を用いた触媒活性試験。
主要な成果:
- 穏やかな条件下(70℃)で高いエポキシド選択率(96-100%)と転化率(88-100%)を達成しました。
- 触媒は、cis-シクロオクテン、dl-リモネン、および脂肪酸メチルエステルのエポキシ化に有効であることが示されました。
- 酸化剤として過酸化水素を使用すると沈殿が誘発され、自己分離型触媒が生成しました。
結論:
- 反応誘起沈殿により、新しい自己分離型モリブデン触媒が首尾よく調製されました。
- この触媒は、均一系触媒活性と不均一系触媒回収のユニークな組み合わせを提供します。
- このアプローチは、複雑なエポキシドを製造するための持続可能な戦略を提示します。
関連する概念動画
Preparation of Epoxides
9.2K
Overview
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
Epoxides result from alkene oxidation, which can be achieved by a) air, b) peroxy acids, c) hypochlorous acids, and d) halohydrin cyclization.
Epoxidation with Peroxy Acids
Epoxidation of alkenes via oxidation with peroxy acids involves the conversion of a carbon–carbon double bond to an epoxide using the oxidizing agent meta-chloroperoxybenzoic acid, commonly known as MCPBA. Since the O–O bond of peroxy acids is very weak, the addition of electrophilic oxygen of peroxy acids to...
9.2K
Sharpless Epoxidation
5.1K
The conversion of allylic alcohols into epoxides using the chiral catalyst was discovered by K. Barry Sharpless and is known as Sharpless epoxidation. The use of a chiral catalyst enables the formation of one enantiomer of the product in excess. This chiral catalyst is mainly a chiral complex of titanium tetraisopropoxide and tartrate ester (specific stereoisomer). The stereoisomer used in the chiral catalyst dictates the formation of the enantiomer of the product. In other words, the use of...
5.1K
Test for Homogeneity
2.4K
The goodness–of–fit test can be used to decide whether a population fits a given distribution, but it will not suffice to decide whether two populations follow the same unknown distribution. A different test, called the test for homogeneity, can be used to conclude whether two populations have the same distribution. To calculate the test statistic for a test for homogeneity, follow the same procedure as with the test of independence. The hypotheses for the test for homogeneity can...
2.4K
Structure and Nomenclature of Epoxides
7.9K
Cyclic ethers are heterocyclic compounds with an oxygen atom in the ring along with carbon atoms. They are named depending on the number of carbon atoms present in their ring system. Cyclic ethers with a three-membered ring system are called “oxirane”, four-membered ring systems as “oxetane”, five-membered ring systems as “oxolane”, and six-membered ring systems as “oxane”. The cyclic structure of these rings imposes angle strain, and this strain...
7.9K
Acid-Catalyzed Ring-Opening of Epoxides
8.8K
Epoxides that are three-membered ring systems are more reactive than other cyclic and acyclic ethers. The high reactivity of epoxides originates from the strain present in the ring. This ring strain acts as a driving force for epoxides to undergo ring-opening reactions either with halogen acids or weak nucleophiles in the presence of mild acid. The acid catalyst converts the epoxide oxygen, a poor leaving group, into an oxonium ion, a better leaving group, making the reaction feasible. The...
8.8K
Base-Catalyzed Ring-Opening of Epoxides
10.1K
Due to their highly strained structures, epoxides can readily undergo ring-opening reactions through nucleophilic substitution, either in the presence of an acid or a base. The nucleophilic substitution reactions in the presence of acid are called acid-catalyzed ring-opening reactions, and nucleophilic substitution reactions in the presence of a base are called base-catalyzed ring-opening reactions. Epoxides undergo base-catalyzed ring-opening reactions in the presence of a strong nucleophile...
10.1K


