Amine Type Research Articles

Acylated anthocyanin inhibited the formation of heterocyclic amines in hybrid chemical model system and its underlying mechanism

Enzymatic acylation was employed to synthesize acylated anthocyanin, and a hybrid chemical model system was used for the formation of heterocyclic amines. And the inhibition effect and underline mechanism were investigated by analyzing the variations in important precursors and intermediates. Results confirmed that cyanidin-3-(6-cinnamoyl) -glycosidase (C3(6C)G) with a purity of 98.9% was obtained. HPLC identified seven types of heterocyclic amines (IQ, MeIQx, 4,8-DimeiqX, Norharman, Harman, PhIP, and AαC) generated in the chemical model. (C3(6C)G) showed a good concentration-dependent manner for the inhibition effect on most HCAs except for MeIQx and PhIP. It also suppressed the glucose content, showed a dose-dependent manner in creatine/creatinine inhibition, and could scavenge formaldehyde, acetaldehyde, and phenylacetaldehyde. Two potential pathways might be involved: 1. by inhibiting the content of precursors (glucose and creatinine), competing with the formation of amino acids, to suppress HCAs generation; 2 through the removal of reactive carbonyl, reducing its reaction with creatinine.

The protective and therapeutic effects of agmatine on isoproterenol-induced myocardial injury in rats

Chronic inflammation and oxidative stress can contribute to the development of cardiovascular diseases. Isoproterenol (ISO), a synthetic catecholamine, is used to study the effects of drugs on cardiotoxicity. Agmatine (AGM) is a type of biogenic amine produced through the decarboxylation of arginine. The purpose of the current study was to evaluate the effects of AGM against ISO-induced cardiotoxicity due to the described roles of AGM in cardiovascular disease. Four groups of thirty-two Wistar Albino rats were divided equally as control, ISO, AGM+ISO, and ISO+AGM. ISO was administered intraperitoneally (i.p.) twice at a dose of 150 mg/kg, at 24-hour intervals. Prior to and after ISO injection, 20 mg/kg of AGM was injected i.p. Hemodynamic measurements and serum and tissue biochemical analyses were evaluated at the end of the experiment. The levels of glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), and malondialdehyde (MDA) in the tissue were measured. In the ISO group, levels of lactate dehydrogenase (LDH) and creatine kinase (CK) were increased significantly (p<0.05). Co-administration of ISO and AGM significantly reduced CK and LDH levels (p<0.05). MDA levels increased in the ISO-treated group but decreased in the AGM-treated groups (p<0.05). Notably, there was a reduction in the CAT level in the ISO treatment group (p<0.05). CAT was found to be significantly increased (p<0.05) in the groups that received AGM compared to the ISO group. AGM+ISO group had a reduced density of degenerated cardiomyocytes and granulation tissue compared to the ISO group (p<0.05). Although granulation tissue demonstrated a significant reduction in the ISO+AGM group in comparison to the ISO group (p<0.05). In this study, the results indicate that AGM treatment can potentially inhibit ISO-induced myocardial injury and vascular dysfunction by preserving vascular integrity. Notably, the protective effects of AGM on cardiac damage appear to outweigh its therapeutic benefits, as shown by histopathological analysis

Effect of Amine Type on Lignin Modification to Evaluate Its Reactivity in Polyol Construction for Non-Isocyanate Polyurethanes (NIPU)

Polyols are groups of organic compounds which contain carbon and are randomly linked to other atoms, especially carbon-carbon and carbon-hydrogen. These compounds are mainly used as reactants to make other polymers. Among biopolymers, lignin is regarded as the base of a new polymer in polyol construction. The present study aimed to investigate the effects of amine type (diethylenetriamine and ethylenediamine) on the modification of lignin-based polyols, so as to provide an alternative to petroleum polyols and, in turn, increase functional groups and reduce their harm to humans’ health and the environment. To this aim, first, lignin was extracted from raw liquor. Next, the extracted lignin was reacted with diethylenetriamine (DETA) and ethylenediamine (EDA). Finally, the Mannich method was used for the reaction between amine lignin and propylene carbonate. The results of the Fourier Transform Infrared (FTIR) spectroscopy analysis showed that modification with DETA led to more structural change in lignin and peak 1100 indicates the presence of C–O bond related to urethane bonds in modified lignin. Moreover, adding propylene carbonate to aminated lignin did not result in much change in the results of the FTIR analysis. Additionally, urethane bonds can be seen in the results of GPC at 400°C–500°C. Furthermore, a slight decrease in thermal stability was observed in lignin modified with amine and propylene carbonate, compared to the raw lignin sample.

Synthesis of Azo Dyes and Generation of Dot Matrix Using Thin-Layer Chromatography

Thin-layer chromatography, which involves the movement of dyes along a silica-coated plate, is used to observe the progress of chemical reactions and to separate mixtures. We took advantage of this phenomenon to devise a method for generating patterns in the shape of numbers with dots (dot matrix). We prepared the azo dyes necessary for generating the dot matrix and successfully generated dot matrix images of numbers 0 to 9 using three azo dyes synthesized from two types of aromatic amines and three types of phenols. All plates were developed in a hexane:acetone = 5:1 solvent. The advantage of this study is that all azo dyes necessary for drawing can be synthesized from common raw materials. Both the dye synthesis and dot matrix generation can be carried out as part of practical work intended for first-year university students. Alternatively, the experiments could be conducted using the dyes prepared in advance by the instructor, and high school students could be encouraged to consider which dye solution to spot on each lane to draw their desired number by dot matrix.

Multicatalysis protocol enables direct and versatile enantioselective reductive transformations of secondary amides.

The catalytic asymmetric geminal bis-nucleophilic addition to nonreactive functional groups is a type of highly desirable yet challenging transformation in organic chemistry. Here, we report the first catalytic asymmetric reductive/deoxygenative alkynylation of secondary amides. The method is based on a multicatalysis strategy that merges iridium/copper relay catalysis with organocatalysis. A further combination with the palladium-catalyzed alkyne hydrogenation allows the one-pot enantioselective reductive alkylation of secondary amides. This versatile protocol allows the efficient synthesis of four types of α-branched chiral amines, which are prevalent structural motifs of active pharmaceutical ingredients. The protocol also features excellent enantioselectivity, chemoselectivity, and functional group tolerance to be compatible with more reactive functional groups such as ketone and aldehyde. The synthetic utility of the method was further demonstrated by the late-stage functionalization of two drug derivatives and the concise, first catalytic asymmetric approach to the κ-opioid antagonist aticaprant.

Transparent glass-fiber-reinforced epoxy composites and their optical characteristics

Cured thermosetting epoxy (EP) resins and glass-fiber-reinforced polymer (GFRP) composite materials were prepared to identify the differences in optical properties based on the type of amine curing agent used. The optical properties of the cured product of EP/amine curing agent mixture and transparent GFRP were analyzed using a lens refractometer and UV–Visible spectrophotometer. Among the amine curing agents, the aliphatic amine curing agent PPG-400 has the closest refractive index (RI) to that of glass fiber as well as the highest transmittance. The slight difference in RI between the glass fiber and EP/PPG-400 potentially reduces the phase delay, resulting in high transmittance. The above results imply that transparent, high-transmittance GFRP can be prepared by efficient mixing of the amine curing agent.

Regiospecific α-methylene functionalisation of tertiary amines with alkynes via Au-catalysed concerted one-proton/two-electron transfer to O2

Regioselective transformations of tertiary amines, which are ubiquitously present in natural products and drugs, are important for the development of novel medicines. In particular, the oxidative α-C–H functionalisation of tertiary amines with nucleophiles via iminium cations is a promising approach because, theoretically, there is almost no limit to the type of amine and functionalisation. However, most of the reports on oxidative α-C–H functionalisations are limited to α-methyl-selective or non-selective reactions, despite the frequent appearance of α-methylene-substituted amines in pharmaceutical fields. Herein, we develop an unusual oxidative regiospecific α-methylene functionalisation of structurally diverse tertiary amines with alkynes to synthesise various propargylic amines using a catalyst comprising Zn salts and hydroxyapatite-supported Au nanoparticles. Thorough experimental investigations suggest that the unusual α-methylene regiospecificity is probably due to a concerted one-proton/two-electron transfer from amines to O2 on the Au nanoparticle catalyst, which paves the way to other α-methylene-specific functionalisations.

Relationship between cross-linking network structure and phase change performances toward multifunctional epoxy/bio-based wax form-stable phase change materials

High encapsulation rate resulting from the good compatibility between cross-linking network and encapsulated solid–liquid phase change materials (SLPCMs) cannot necessarily result in high enthalpy value for the polymeric PCMs. However, the inner mechanism considering the above fact is not clear due to the lack of suitable model compound systems. In this work, a type of epoxy resin with crystalline alkyl side chains (named D18) and four types of amine curing agents (with similar structure but different polarity and molecular size) were primarily used as the model compound to achieve the encapsulation of beeswax (Bw, a kind of bio-based wax), and then the influence of the cross-linking network structure (using different curing agents) on the phase change performances of the D18/Bw polymeric form-stable PCMs (FSPCMs) was systematically studied. The results suggest that polarity effect and steric hindrance effect are the two factors that affect the phase change performances of the polymeric FSPCMs. Though the encapsulation rate of Bw is the highest (near 70 wt%) in the EPH-Y systems (using 1,3-Cyclohexanebismethylamine as the curing agent), it is the EPM-60 sample (using M−Xylylenediamine as the curing agent and containing 60 wt% Bw) that exhibited the highest enthalpy value of 146.2 J/g. Subsequently, different amount of multi-walled carbon nanotubes (CNT) was introduced to improve the thermal conductivity (TC) and achieve multifunctionalization of the EPM-60 sample. The TC, electromagnetic interference (EMI) shielding performance, and contact angle of the 30 wt% CNT modified EPM-60 sample can reach 1.37 W/mK, 37.4 dB, and 137°, while the enthalpy value can remain 101.1 J/g. This work is very helpful in clarifying the relationship between cross-linking network structure and phase change performances of polymeric FSPCMs, so as to providing theoretical guidance for the cross-linking network structure optimization in preparing other reliable polymeric FSPCMs with high enthalpy value, high reliability, and multifunctionalization.

High-titre production of aromatic amines in metabolically engineered Escherichia coli.

Aromatic amines with diverse physical characteristics are often employed as antioxidants and precursors to pharmaceutical products. As the traditional chemical methods pose serious environmental pollution, there is an arising interest in biomanufacturing aromatic amines from renewable feedstocks. We report the establishment of a bacterial platform for synthesizing three types of aromatic amines, namely, tyramine, dopamine and phenylethylamine. First, we expressed aromatic amino acid decarboxylase from Enterococcus faecium (pheDC) in an Escherichia coli strain with increasing shikimate (SHK) pathway flux towards L-tyrosine. We found that glycerol served as a better carbon source than glucose, resulting in 940 ± 46 mg/L tyramine from 4% glycerol. Next, the genes of lactate dehydrogenase (ldhA), pyruvate formate lyase (pflB), phosphate acetyltransferase (pta) and alcohol dehydrogenase (adhE) were deleted to mitigate the fermentation by-product formation. The tyramine level was further increased to 1.965 ± 0.205 g/L in the shake flask, which was improved by 2.1 times compared with that of the parental strain. By using a similar strategy, we also managed to produce 703 ± 21 mg/L dopamine and 555 ± 50 mg/L phenethylamine. We demonstrated that the knockout of ldhA-pflB-pta-adhE is an effective strategy for improving aromatic amine productions. This study achieved the highest aromatic amine titres in E. coli under shake flask reported to date.

Adsorbent screening for glycidyl methacrylate extraction: a preliminary study using density functional theory

The difficulty in detecting glycidyl esters (GE), a potentially carcinogenic contaminant group in palm oil, remains a concern for the palm oil producers. The inefficient sample preparation step due to insufficient knowledge on GE interaction with extraction adsorbents is a challenge in improving the GE detection. This work aims to study the adsorption of glycidyl methacrylate (GM; a representative of GE) on adsorbents commonly used for chemical extraction (long-chain hydrocarbon, primary secondary amine and silica) based on the density functional theory. Gaussian 09W software (B3LYP/LanL2DZ) was used for chemical structure optimization and frequency calculation. GM adsorptions were generally found to be nonspontaneous. N-propylethylenediamine (PED; primary secondary amine type of adsorbent) is the most promising adsorbent for extracting GM. The adsorption on PED does not involves any bond breaking and formation, and only physisorption is expected to occur. The process is exothermic and can be referred as the most spontaneous among the non-spontaneous. The more negative ΔEads also implies that the adsorbed GM is more stable on the PED surface than on C18 (long-chain hydrocarbon adsorbent). With that said, the silicon dioxide (silica type of adsorbent) was ruled out as chemical reaction were observed between the adsorbate and the adsorbent.

Generic AI models for mass transfer coefficient prediction in amine‐based CO2 absorber, Part II: RBFNN and RF model

AbstractIn this work, the radial basis function neural network (RBFNN) and random forest (RF) algorithms were employed to develop generic AI models predicting mass transfer coefficient in amine‐based CO2 absorber. The models with operating parameters as input gave quite different prediction performance in different CO2 absorption systems. To secure better applicability, extra parameters related to amine type and packing characteristics were introduced to reasonably describe mass transfer behaviors, respectively. Moreover, the generic models were proposed by considering all influencing factors of mass transfer in CO2 absorber column. Furthermore, the performance of BPNN, RBFNN, and RF models was completely compared and fully discussed in terms of AARE. All three generic models could predict mass transfer coefficient of CO2 absorber very well. It was found that the BPNN models provide the best predication with AAREs of below 5%. The developed generic model could serve as a fast and efficient tool for preliminary selection and evaluation of potential amines for CO2 absorption. The framework of generic ML model development was also clearly presented, which could provide theoretical basis and practical guidance for the implementation and application of ML models in the carbon capture field.

Surface-modified Ti-MOF/TiO2 membrane and its gas-sensing characteristics

A titanium metal–organic framework/titanium dioxide (Ti-MOF/TiO2) composed membrane was fabricated by light inductive growth of Ti-MOF ([Ti2-(TpA)2-NDI] n ; TpA = terephthalic acid, NDI = 1,8,4,5-naphthalene-tetracarboxdiimide) on a titanium dioxide film composite optical waveguide (COWG) substrate. The Ti-MOF/TiO2 membrane conforms to a mesoporous structure with a 24 nm pore size and a 108 nm thickness through continuous growth for 40 min under 340 nm ultraviolet light illumination. Under ambient conditions, in terms of COWG sensors, Ti-MOF/TiO2 exhibited the greatest response to ethylenediamine (EDA), followed by nitrogen dioxide (NO2), methylamine and trimethylamine, when exposed to 15 types of benzenes, amines and acidic gases. To improve response selectivity, the Ti-MOF/TiO2 film was modified with 1,3,3-trimethylindolinonaphthospirooxazine (SP), forming an SP@Ti-MOF/TiO2 COWG. This modified COWG showed improved selectivity response by showing robust response to EDA and a negligible response to others. When an EDA gas molecule was adsorbed on the surface of the membrane, charge transfer between them preferentially occurred, leading to a change in the optical parameter. The surface-modified SP@Ti-MOF/TiO2 COWG showed a fast (3 s) and reversible response with a wide detection range (0.1–1000 parts per billion) to EDA gas without the interference of benzene, toluene, xylene, styrene and chlorobenzene; acidic gases; and other amines.

Development of the Method for Nusinersen and Its Metabolites Identification in the Serum Samples of Children Treated with Spinraza for Spinal Muscular Atrophy.

The application of oligonucleotides as drugs for different genetic diseases is increasing rapidly. Since 2016 they are used during spinal muscular atrophy treatment with the use of nusinersen oligonucleotide. The purpose of this study was to improve methods for the analysis of serum samples of patients treated with nusinersen. The results showed that liquid-liquid extraction (with phenol/chloroform) is insufficient and an additional purification step using solid-phase extraction is necessary. The best results were obtained for microextraction by packed sorbents. Important parameters in the optimization of the method were mainly the type of amine in the mobile phase and the stationary phase. Both influenced the selectivity of metabolite separation and thus their correct identification; while amine type impacted also the intensity of signals. Finally, the highest resolution of separation and the highest peak areas were obtained for N,N-dimethylbutylamine or N,N-diisopropylthylamine with an octadecyl column with a terminal aryl group. Over a dozen of metabolites were successfully identified with the use of methods developed during the study. The 3′ exonucleases and 5′ exonucleases were mainly responsible for nusinersen metabolism, consequently, 3′end shortmers, and 5′end shortmers were observed, as well as metabolites with simultaneous loss of bases at both ends of the sequence. However, some depurination and depyrimidination products were also identified. To the best of our knowledge, this is the first report on nusinersen and its metabolite identification in serum samples by liquid chromatography and mass spectrometry.

Selective co-crystallization separation of sucrose-6-acetate from complicated sucrose acylation system and facile removal of co-former: Process optimizations and mechanisms

The searching for the facial and highly efficient separation method of sucrose-6-acetate (SA-6) in the acylation process seems significant for the production of sucralose. In this work, an efficiently selective co-crystallization strategy of SA-6 from the complicated sucrose acylation mixture has been developed, i. e. firstly, selective co-crystallization using acetic acid (HAc) as a cheap and green co-former (operation I), and co-former removal by triethylamine (TEA) (operation II). The crystal structure of SA-6·HAc co-crystal in the operation I has been determined, it is a 3D hydrogen-bonding network with HAc inserting among the SA-6 layers, whose cavity size is 5.56 × 7.54 Å. And the optimization on two operations have been conducted, including HAc dosage, solvent/aliphatic amine types and dosage, separation time/temperature. Based on the optimal conditions, the high SA-6 separation efficiency of 90.33 % in 1.5 h can be achieved, during which relative selectivity coefficient (αX) is lower than 0.003, deacidification ratio (δ) is higher than 99.47 %, and the product purity is 99.86 % (wt). Furthermore, the selective co-crystallization and co-former removal mechanisms were proposed base on crystal structure and theoretical calculations, in which thermally stable co-crystals, proper solvent size and acid-base coupling drive these processes. This strategy can enhance the separation efficiency of acylation process in sucralose production greatly.

Selective One-Pot Cascade Synthesis of N-Substituted Highly Functionalized Pyrroles from Unprotected Sugars, Primary Amines, and Oxoacetonitriles.

A one-pot, three-component cascade reaction between unprotected sugars, primary amines, and 3-oxoacetonitriles gave N-substituted 2,3,5-functionalized pyrroles or N-substituted 2,3,4-functionalized pyrroles in excellent yields and selectivities. The selectivity of the reaction was achieved by simple control of the sequence of substrate addition. The reaction showed a wide substrate scope, and various types of sugars, primary amines, and oxoacetonitriles reacted smoothly. The work demonstrates a highly desired simple reaction for embedding nitrogen into sugars to produce valuable N-heterocyclic compounds that are amenable to further modifications to natural products and drug intermediates.

Preparation of an anion stationary phase modified by quaternary ammoniated allyl glycidyl ether

制备了一种季铵化烯丙基缩水甘油醚(allyl glycidyl ether, AGE)改性聚合物基质的阴离子固定相应用于离子色谱系统。它是利用AGE与水解的聚甲基丙烯酸缩水甘油酯-二乙烯基苯(poly(glycidylmethacrylate-divinylbenzene, GMA-DVB)微球表面残留双键通过表面自由基共聚,再通过N,N-二甲基乙醇胺(一种叔胺)进行开环反应制备得到的。通过考察有机叔胺类型、微球水解、单体和引发剂用量、反应温度和时间对7种阴离子分离性能的影响,优化了制备条件。采用扫描电镜、元素分析对所得阴离子固定相进行了表征。结果表明,采用预先水解的GMA-DVB微球(水解过程中微球表面丰富的环氧基团转化为羟基)相对于直接采用GMA-DVB微球有助于降低固定相的交换容量和微球自身的非离子吸附作用;通过淋洗液浓度和目标离子保留因子的拟合结果证实了该固定相保留机理为典型的离子交换作用。使用碳酸根淋洗液,在优化的色谱条件下,该固定相可在13 min内实现常见7种无机阴离子的基线分离,并表现出较高的柱效(Cl-理论塔板数为49000块/m)。该色谱柱实用性通过分析自来水实际样品进行了验证。

Insights into the different mixing states and formation processes of amine-containing single particles in Guangzhou, China

The formation processes of particulate amines are closely related to their emission sources and secondary reactions, which can be revealed through the investigation of their real-time mixing states in individual particles. The mixing states of methylamine (MA)-, trimethylamine (TMA)-, and diethylamine (DEA)-containing particles were studied using a high-performance single particle aerosol mass spectrometer (HP-SPAMS) in Guangzhou, China, in January 2020. The sharp increase in TMA particles was found to be closely associated with the increase in the ambient relative humidity (RH), while the MA- and DEA-containing particles were not similarly influenced by the changes in the RH. The prominent enrichment of secondary oxygenated organics in DEA particles during the daytime was consistent with the active period of photochemistry, implying that the sharp decrease in DEA particles in the afternoon was likely due to photo-oxidation of the DEA. The number fraction (Nf) of DEA particles, the Nf of the nitrate in the DEA particles, and the abundance of nitrate increased as the NOx content all increased during the nighttime, suggesting that the formation of DEA·HNO3 salt was the dominant pathway of particulate DEA production. These results are consistent with our previous measurements in Nanjing, confirming the general and distinct mixing states of TMA and DEA particles. Positive matrix factorization analysis revealed that the total fraction of the more oxidized organics factor and the less oxidized organics factor were much higher in the DEA particles (26.9 %) than in the TMA particles (9 %), confirming the significant enrichment of oxygenated species in the DEA particles. The different mixing states of the amines revealed the unique response of each type of amine to the same atmospheric environment, and the prominent mixing states of the DEA with secondary oxygenated species suggest the potential role of DEA in tracing the evolution of organic aerosols.

Protonated amines mediated CO2 mineralization of coal fly ash and polymorph selection of CaCO3

The extensive consumption of acid and alkaline reagents is the most critical challenge hindering the development of the pH-swing process for CO2 mineralization. To deal with the problem, the present paper demonstrates the feasibility of using protonated amine as the reagent in coal fly ash (CFA) based leaching-mineralization process. The protonated amine could leach Ca2+ from CFA and be converted into free amine. The free amine was supposed to be in-situ regenerated into protonated amine by grab protons released from the CaCO3 precipitation reaction. 13 typical amines with varying amino types, pKa values, and side-chain length, were selected to systematically investigate the effects of amino groups on Ca2+ leaching performance from CFA, carbonation performance, CaCO3 nucleation, and crystal growth, as well as the process mechanism. Results indicated that effective Ca leaching, CaCO3 precipitation, and protonated amine regeneration were achieved. There was a linear relationship between the Ca utilization efficiency and pKa values of different amines. TEA obtained the highest CaCO3 yield and Ca utilization efficiency of 56.8 % and 16.8 %, respectively. In addition, amines provided excellent control of the size, polymorph, and morphology of the CaCO3 product. The primary amino group had a more pronounced effect on vaterite stabilization than secondary and tertiary ones. Introducing a side chain could promote the vaterite transforming to calcite and increasing chain length could decrease the vaterite particle size. Moreover, the maximal utilization efficiency in MEA was 15.9 % at conditions: 160 g/L solid to liquid ratio, 58 % degree of protonation, and 2.0 mol/L MEA concentration.

Orthogonal Access to α‐/β‐Branched/Linear Aliphatic Amines by Catalyst‐Tuned Regiodivergent Hydroalkylations

AbstractLinear, α‐branched, and β‐branched aliphatic amines are widespread in pharmaceuticals, agrochemicals, and fine chemicals. Thus, the development of direct and efficient methods to these structures in a tunable manner is highly desirable yet challenging. Herein, a catalyst‐controlled synthesis of α‐branched, β‐branched and linear aliphatic amines from Ni/Co‐catalyzed regio‐ and site‐selective hydroalkylations of alkenyl amines with alkyl halides is developed. This catalytic protocol features the reliable prediction and control of the coupling position of alkylation to provide orthogonal access to α‐branched, β‐branched and linear alkyl amines from identical starting materials. This platform unlocks orthogonal reactivity and selectivity of nickel hydride and cobalt hydride chemistry to catalytically repurpose three types of alkyl amines under mild conditions.

Insights into the interaction between typical amines and alkaline minerals for improved CO2 absorption and mineralization

AbstractAmine scrubbing is a mature technology to cut down CO2 emissions from human activities but suffers from a high energy consumption of solvent regeneration. The integrated CO2 absorption and mineralization (IAM) process can effectively reduce the energy consumption of amine regeneration by replacing traditional thermal regeneration with chemical regeneration via CO2 mineralization. However, a fundamental understanding of the interaction between typical amines and alkaline minerals was still lacking. In this paper, the effects of amine types on amine regeneration, alkaline metal leaching, and CaCO3 precipitation during the IAM process were explored by using five typical amines and Ca(OH)2/Mg(OH)2. Results showed very different regeneration kinetics and efficiencies were observed in five selected amine solutions, which displayed a decreased performance in the order TEA > MDEA > DEA > AMP > MEA. The regeneration performance was significantly affected by the dissolution of Ca(OH)2/Mg(OH)2 which was inversely proportional to the trend of their pKa values. TEA displayed the largest regeneration efficiency of about 95% by Ca(OH)2 and 83% by Mg(OH)2, which was much larger than other amines reported in the open literature, due to its lower pKa value than other selected amines. More interestingly, the particle size of CaCO3 produced from amine solutions was smaller than that from CaCl2 solution reported in the literature. There was a rough linear relationship between CaCO3 particle size and amine pKa values. TEA induced the formation of nano scaled CaCO3, which might be attributed to the adsorbing of TEA on the CaCO3 crystal and inhibiting the crystal growth. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd.