Kinetics and new Bronsted correlations study of CO2 absorption into primary and secondary alkanolamine with and without steric-hindrance
Kinetics and new Bronsted correlations study of CO2 absorption into primary and secondary alkanolamine with and without steric-hindrance
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有或没有空间位阻的伯烷醇胺和仲烷醇胺吸收 CO2 的动力学和新布朗斯台德相关性研究
DOI：
10.1016/j.seppur.2019.115998
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发表时间：
2020
影响因子：
8.6
通讯作者：
Zhang Haiyan
中科院分区：
文献类型：
--
作者：
Liu Sen;Ling Hao;Gao Hongxia;Tontiwachwuthikul Paitoon;Liang Zhiwu;Zhang Haiyan
为了弄清楚伯烷醇胺和仲烷醇胺的空间位阻及其对 CO2 吸收性能和 Brønsted 相关性的影响，使用 pH 计和停流技术在 293–313K 下研究了 9 种烷醇胺的 pKa 值和动力学数据（二级反应速率，k2）。测试的胺包括单乙醇胺（MEA）、二乙醇胺（DEA）、2-甲基乙炔醇胺（MAE）、2-乙基乙炔醇胺（EAE）、1-氨基-2-丙醇（1-AP）、3-氨基-1-丙醇（3-AP）、2-氨基-2-甲基-1-丙醇（AMP）、2-氨基-1-丙醇（2-AP）和3-氨基-1,2-丙二醇（3-APD）。此外，还测试了MEA、MAE、EAE、2-AP和AMP的平衡溶解度，以评价空间位阻对氨基甲酸酯稳定性的影响。动力学、溶解度和Brønsted相关性的综合分析表明，α-C原子上连接的烷基所造成的空间位阻对溶解度和溶解度的影响比氨基上连接的烷基所造成的空间位阻显着。此外，空间无位阻胺和位阻胺的 k2 和 pKa 值分别在 293-313K 下拟合，预测 k2 和实验 k2 之间的 AARD 分别为 5.2% 和 16.5%。最后，根据分子结构和实验结果，提出了空间位阻效应对反应动力学的影响机制。
To figure out the steric hindrance and its magnitude effects on CO2absorption performance and Brønsted correlations of primary and secondary alkanolamines, the pKa values and kinetics data (second order reaction rate,k2) were investigated for nine alkanolamines at 293–313 K using pH meter and stopped-flow technique. The tested amines include monoethanolamine (MEA), diethanolamine (DEA), 2-methyl-ethynolamine (MAE), 2-ethyl-ethynolamine (EAE), 1-amino-2-propanol (1-AP), 3-amino-1-propanol (3-AP), 2-amino-2-methyl-1-propanol (AMP), 2-amino-1-propanol (2-AP) and 3-Amino-1,2-propanediol (3-APD). In addition, the equilibrium solubility of MEA, MAE, EAE, 2-AP and AMP were tested for evaluation of steric hindrance effect on carbamate’s stability. The comprehensive analysis of kinetics, solubility and Brønsted correlations indicated that the steric hindrance caused by alkyl group(s) attached to α-C atom has much significant effect onk2and solubility than that caused by alkyl group connected to amino group. Moreover, thek2and pKavalues for sterically unhindered and hindered amines were separately fitted at 293–313 K, giving out an AARD of 5.2% and 16.5% between predicted and experimentalk2, respectively. Finally, based on molecular structures and experimental results, mechanism of steric hindrance effect on reaction kinetics was proposed.