在混合纳米结构中,基于氧化石墨烯可循环脱氨酸的可循环脱
Ziwei Tang1, Hao Chen, Xiaowei Chen
1Department of Materials Science, Fudan University, Shanghai, China.
Journal of the American Chemical Society
|March 16, 2012
概括
石墨烯氧化物纳米结构使可回收氨酸脱,释放100°C以下的纯. 这有助于氨基 (AB) 的有效化学再生,以实现可持续的储存.
科学领域:
- 材料科学 材料科学 材料科学
- 化学工程是化学工程的重要组成部分.
- 纳米技术纳米技术
背景情况:
- 氨基 (AB) 是一个有前途的储物材料,但遭受不可逆转的分解.
- 来自AB的高效和可回收的释放对于实际应用至关重要.
- 石墨烯氧化物 (GO) 为纳米封闭和催化提供了独特的特性.
研究的目的:
- 开发一种可回收的系统,从氨 (AB) 产生气.
- 研究石墨烯氧化物 (GO) 在增强AB脱过程中的作用.
- 为了在低温下实现高纯度的释放.
主要方法:
- 基于氧化石墨烯 (GO) 的混合纳米结构的制造.
- 纳米结构的酸激活,以增强催化活性.
- 在GO结构中对氨 (AB) 进行纳米封闭.
- 释放的特征和副产品的形成.
- 从脱产品中化学再生AB.
主要成果:
- 基于GO的混合纳米结构使得AB的可回收脱.
- 在100°C以下的温度下,超过2个等价的纯2被释放出来.
- 聚波拉烯 (PB) 是脱的唯一产物.
- 通过将PB与水进行反应,可以实现AB的有效化学再生.
结论:
- 基于氧化石墨烯的混合纳米结构提供了一个有效的平台,用于从氨酸中储存可回收的.
- 酸激活和纳米封闭的联合策略是实现低温,高纯度释放的关键.
- 从聚乙烯 (PB) 轻松再生AB为燃料应用提供了可持续的途径.
相关概念视频
Hydroboration-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.
Alkynes 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.
Preparation of Amines: Reductive Amination of Aldehydes and Ketones
Carbonyl compounds and primary amines undergo reductive amination first to produce imines, followed by secondary amines in the same reaction mixture, using selective reducing agents like sodium cyanoborohydride or sodium triacetoxyborohydride. Reductive amination produces different degrees of substitution of amines depending on the starting amine substrate.
Regioselectivity and Stereochemistry of Hydroboration
A significant aspect of hydroboration–oxidation is the regio- and stereochemical outcome of the reaction.
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn stereochemistry.


