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首页> 外文期刊>ACS catalysis >Glycolaldehyde as a Bio-Based C-2 Platform Chemical: Catalytic Reductive Amination of Vicinal Hydroxyl Aldehydes
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Glycolaldehyde as a Bio-Based C-2 Platform Chemical: Catalytic Reductive Amination of Vicinal Hydroxyl Aldehydes

机译：甘科醛作为基于生物的C-2平台化学品：致丙烯酸羟基醛的催化还原胺化

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摘要

Reductive amination of glycolaldehyde (GA), the smallest sugar molecule and obtainable from biomass, creates a versatile platform for ethylamine products, potentially replacing current pathways via toxic ethylene oxide and dichloroethane. Given the high reactivity of alpha-OH carbonyls, the main challenge was control of selectivity in a cascade of parallel and consecutive reactions during reductive amination. The type of solvent and catalyst, preferably methanol and Pd, respectively, are key enabling parameters to achieve high product yields. A kinetic study on product intermediates accompanied with detailed product analysis (MS and NMR) suggested a general mechanistic scheme and validation with density functional theory calculations provided a rational understanding of the solvent effect in terms of energetics and kinetics. Primary alkanolamines (AA) such as 2-(dimethylamino)-ethanol are preferred products, and large excess of the amine reagent is not required to reach almost quantitative yields. Interestingly substoichiometric amine-to-GA ratio allows for high yield of higher (consecutive) AAs such as N-methyldiethanolamine (MDEA) and triethanolamine, for which a peculiar cyclic 5-membered oxazolidinic precursor was analyzed (e.g., for reaction with monomethylamine to MDEA). The shift to diamine-selective (DA) reactions is possible by switching to a two-step one-pot approach. With ethylene glycol as a preferred solvent, high yield of an unsaturated C-2-enediamine precursor is obtained under an inert atmosphere, followed by its metal-catalyzed hydrogenation at elevated temperature to the final DA product such as N,N,N',N'-tetramethylethylene-diamine. A conceptual model of the catalytic reductive amination routes that allows production of a variety of ethylamines with up to +90 C % yield is thus presented. The successful preparation and sensory assessment of a GA-based diester quat in fabric softener formulations demonstrates the viability of a full bio-based and drop-in production route for high-value chemicals, directly from GA as a platform molecule.
机译：糖醛（GA），最小糖分子和可从生物质获得的还原胺化为乙胺产物产生多功能平台，可能通过有毒环氧乙烷和二氯乙烷替换电流途径。鉴于α-OH羰基的高反应性，主要挑战是在还原胺化过程中控制平行和连续反应的级联和连续反应中的选择性。溶剂和催化剂的类型分别是甲醇和Pd，是可以实现高产物产率的关键。伴有详细产品分析的产物中间体（MS和NMR）的动力学研究表明了一种通用机制方案和密度函数理论计算的验证提供了对能量学和动力学方面的溶剂效应的理性理解。诸如2-（二甲基氨基） - 乙醇的初级链烷醇胺（AA）是优选的产物，并且不需要大量过量的胺试剂来达到几乎定量的产率。有趣的是替代胺-Ga比率允许高产率更高（连续）Aas，例如N-甲基二乙醇胺（MDEA）和三乙醇胺，分析了一种特殊的环状5-元恶唑烷蛋白前体（例如，与单甲胺反应到MDEA ）。通过切换到两步1罐方法可以转变为二胺 - 选择性（DA）反应。乙二醇作为优选的溶剂，在惰性气氛下获得不饱和的C-2-己二胺前体的高产率，然后在升高的温度下进行金属催化的氢化，以最终的DA产品如N，N，N'， N'-四甲基乙烯二胺。因此，提出了允许生产多种乙胺具有高达+ 90c％的乙胺的催化还原胺化途径的概念模型。在织物柔软剂制剂中的GA基二酯Quat的成功制备和感官评估表明了直接从Ga作为平台分子的高价值化学物质的全生物基和下降生产途径的活力。

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