Low viscosity alkanolguanidine and alkanolamidine liquids for CO<sub>2</sub>capture
作者:Phillip K. Koech、Jian Zhang、Igor V. Kutnyakov、Lelia Cosimbescu、Suh-Jane Lee、Mark E. Bowden、Tricia D. Smurthwaite、David J. Heldebrant
DOI:10.1039/c2ra22801g
日期:——
Global carbon dioxide (CO2) emission is expected to increase tremendously with the shift to coal-powered plants for energy generation. Capture and sequestration of CO2 are needed to mitigate environmental effects. Solvents currently used for this are the energy-intensive aqueous amines. Here we present 10 advanced solvents called alkanolguanidines and alkanolamidines that are potentially energy-efficient CO2-capture solvents. These solvents were synthesized in 1–3 steps from commercially available materials. One alkanolamidine derived from a 1,8-diazabicyclo[5.4.0]-undec-7-ene (DBU) base core has a low vapor pressure and a high viscosity, resulting in low CO2 uptake capacity at standard temperature and pressure (STP). Three imidazoline base derived alkanolamidines were non-viscous but do not bind CO2 at STP, however, under mild pressure they effectively capture 7–10 wt%, making them suitable for high-pressure CO2 capture. Six novel alkanolguanidine molecules have low vapor pressure and low viscosity (<10 cP) which enable high CO2 uptake at STP. These compounds bind CO2 chemically via the alcohol moiety forming zwitterionic guanidinium and amidinium alkylcarbonate ionic liquids. These materials can be regenerated thermally by heating the alkylcarbonate to 75 °C. CO2 binding capacities of up to 12 wt% were achieved using several of these compounds at STP. Through this study we found that alkanolguanidines have low viscosity, are non-volatile, have high CO2 uptake at STP and are tolerant to water; thus we selected one compound for physical property testing.
随着能源生产转向煤电厂,全球二氧化碳(CO2)排放量预计将大幅增加。需要对二氧化碳进行捕集和封存,以减轻对环境的影响。目前用于此目的的溶剂是高能耗的水胺。在此,我们介绍了 10 种名为烷醇胍和烷醇酰胺的先进溶剂,它们可能是高效节能的二氧化碳捕集溶剂。这些溶剂是用市场上可买到的材料通过 1-3 个步骤合成的。其中一种由 1,8-二氮杂双环[5.4.0]-十一碳-7-烯(DBU)基核衍生的烷醇脒具有低蒸汽压和高粘度,因此在标准温度和压力(STP)下的二氧化碳吸收能力较低。三种由咪唑啉基衍生的烷醇酰胺不具粘性,但在标准温度和压力下不结合二氧化碳,不过,在温和的压力下,它们能有效捕获 7-10 wt%的二氧化碳,因此适用于高压二氧化碳捕获。六种新型烷醇胍分子具有低蒸气压和低粘度(<10 cP),可在 STP 时吸收大量二氧化碳。这些化合物通过醇分子与二氧化碳发生化学结合,形成齐聚物胍和脒烷基碳酸酯离子液体。通过将烷基碳酸酯加热到 75 °C,可对这些材料进行热再生。在 STP 条件下,使用其中几种化合物可实现高达 12 wt% 的二氧化碳结合能力。通过这项研究,我们发现烷醇胍的粘度低、不易挥发、在 STP 条件下具有较高的二氧化碳吸收能力,并且耐水;因此我们选择了一种化合物进行物理性质测试。