CAJ | 학술논문

利用 13C NMR技术对CO2捕获叔胺溶剂进行了碳元素的定量研究,主要考察了对胺溶剂解吸热影响较大的3HCO?的生成规律.重点对叔胺分子结构中羟基官能团( OH)、羟烷基数目、烷基支链及氮原子(N)所连接烷基链大小对胺溶剂生成 3HCO?的影响.在20℃条件下分别对1 mol·L?1具有不同CO2负载的1-二甲基氨基-2-丙醇(1DMA2P)、N-甲基二乙醇胺(MDEA)、3-二甲氨基-1-丙醇(3DMA1P)、二乙氨基-2-丙醇(1DEA2P)、N,N-二乙基乙醇胺(DEEA)、N,N-二甲基乙醇胺(DMMEA)及三乙醇胺(TEA)溶液进行了 13C NMR测试研究.实验结果显示:在相同浓度的叔胺水溶液中,同一CO2负载下的叔胺-CO2-水体系中 3HCO?的含量顺序为:DMMEA>MDEA>3DMA1P>1DMA2P>TEA>DEEA>1DEA2P.通过对各叔胺分子结构中N原子的电子云密度大小及空间位阻效应分析,得出如下结论:3DMA1P分子中 OH官能团离N原子的距离大于其在DMMEA分子中的距离,导致其生成了较少的 3HCO?;DMMEA分子中N原子上连接的烷基链小于DEEA分子中N原子上的烷基链,导致DMMEA溶液中生成了更多 3HCO?;MDEA分子中羟烷基数目少于TEA分子中的羟烷基数目,且MDEA比TEA多了一个甲基,导致MDEA溶液中含有更多的 3HCO?;3DMA1P相比1DMA2P、DEEA相比1DEA2P分子中都少了一个甲基支链,导致 3DMA1P 溶液相比 1DMA2P 溶液、DEEA 溶液相比 1DEA2P 溶液生成了更多的3HCO?.
이용 13C NMR기술대CO2포획숙알용제진행료탄원소적정량연구,주요고찰료대알용제해흡열영향교대적3HCO?적생성규률.중점대숙알분자결구중간기관능단( OH)、간완기수목、완기지련급담원자(N)소련접완기련대소대알용제생성 3HCO?적영향.재20℃조건하분별대1 mol·L?1구유불동CO2부재적1-이갑기안기-2-병순(1DMA2P)、N-갑기이을순알(MDEA)、3-이갑안기-1-병순(3DMA1P)、이을안기-2-병순(1DEA2P)、N,N-이을기을순알(DEEA)、N,N-이갑기을순알(DMMEA)급삼을순알(TEA)용액진행료 13C NMR측시연구.실험결과현시:재상동농도적숙알수용액중,동일CO2부재하적숙알-CO2-수체계중 3HCO?적함량순서위:DMMEA>MDEA>3DMA1P>1DMA2P>TEA>DEEA>1DEA2P.통과대각숙알분자결구중N원자적전자운밀도대소급공간위조효응분석,득출여하결론:3DMA1P분자중 OH관능단리N원자적거리대우기재DMMEA분자중적거리,도치기생성료교소적 3HCO?;DMMEA분자중N원자상련접적완기련소우DEEA분자중N원자상적완기련,도치DMMEA용액중생성료경다 3HCO?;MDEA분자중간완기수목소우TEA분자중적간완기수목,차MDEA비TEA다료일개갑기,도치MDEA용액중함유경다적 3HCO?;3DMA1P상비1DMA2P、DEEA상비1DEA2P분자중도소료일개갑기지련,도치 3DMA1P 용액상비 1DMA2P 용액、DEEA 용액상비 1DEA2P 용액생성료경다적3HCO?.
The amount of bicarbonate is a very important factor for energy consumption in solvent regeneration in CO2 capture process. More bicarbonate in rich amines will lead to lower energy cost in CO2 desorption process. To get a preciously knowledge of the formation of bicarbonate in tertiary amines for design a better absorbent for CO2 capture, a series of tertiary amines such as N-diethylethanolamine (DEEA),1-dimethylamino-2-propanol (1DMA2P), 1-diethylamino-2-propanol (1DEA2P), 3-dimethyl-amino-1-propanol (3DMA1P), N-methyldiethanolamine (MDEA), dimethylmonoethanolamine (DMMEA) and triethanolamine (TEA) with various CO2 loading at 1 mol·L?1 were investigated using 13C NMR technology at 293.15 K. The amount of bicarbonate was calculated by the chemical shift of bicarboante/carboante in 13C NMR spectra. The results showed that the order of the amount of bicarbonate in those tertiary amines is DMMEA>MDEA>3DMA1P>1DMA2P>TEA>DEEA>1DEA2P. Considering the effects of electron density of nitrogen atom (N) and the steric hinderance in those tertiary amines to the formation of bicarbonate in those aqueous tertiary amines solution, it can be concluded that 1) the aqueous 3DMA1P solution produced more bicarbonate compared to DMMEA for its nearer distance of OH to N; 2) the less hydroxyalkyl and one more methyl in amine molecular structure connected to N in MDEA compared to TEA led to more bicarbonate generation; 3) a smaller alkyl connected to N in DMMEA molecular structure compare to DEEA resulted in more bicarbonate was generated in aqueous DMMEA solution; and 4) one more methyl branch existed in 1DMA2P and 1DEA2P molecular structures compared to 3DMA1P and DEEA, respectively, leading to less bicarbonate generation.