Search Results (23)

In chemical absorption for carbon capture, the regeneration heat is a key factor determining solvent regeneration energy consumption, and the sterically hindered amine 2-amino-2-methyl-1-propanol (AMP) has great potential for application. In this paper, a CO₂ reaction heat measurement system designed and constructed by our team was used to perform a comparative study on AMP and monoethanolamine (MEA). Moreover, five additives—MEA, diglycolamine (DGA), diethanolamine (DEA), methyldiethanolamine (MDEA), and piperazine (PZ)—were introduced into AMP-based solutions to investigate the promotion performance of these blended solvents. The results revealed that although AMP exhibited a slower absorption rate compared to MEA, it demonstrated a higher CO₂ loading capacity and cyclic capacity, as well as a lower reaction heat, making it advantageous in terms of regeneration energy consumption. At the same total concentration, the absorption capacity of blended solutions (excluding AMP-MEA solutions) was generally lower than that of single-component AMP solutions. Among these additives, MEA and PZ could enhance the absorption rate clearly yet increase the reaction heat at the same time; DGA and DEA could decrease the overall absorption performance. Generally, AMP-MDEA solutions showed the best desorption performance, with the 15 wt% AMP + 5 wt% MDEA mixture demonstrating the lowest regeneration heat and good cyclic capacity. Full article

The chemical profiles of young and mature wines produced from three grape varieties Merlot, Mavrud, and Sauvignon blanc were analyzed using ¹H nuclear magnetic resonance (NMR) spectroscopy and advanced statistical methods. Furthermore, grape ales―a hybrid of beer and wine—were subjected to analysis to facilitate a comparison of their composition with that of traditional wines. The analysis yielded a total of 37 compounds, which were identified and quantified. Orthogonal partial least squares discriminant analysis (OPLS-DA) models were employed to distinguish the chemical profiles of young and mature wines, as well as those of grape ales. The findings demonstrate that the fermentation and aging processes result in the formation of distinctive chemical signatures in wines, with key compounds such as shikimic acid and fructose contributing to this differentiation. The identified compounds comprise seven alcohols (2,3-butanediol, glycerol, 2-methylpropan-1-ol, 3-methyl-butan-1-ol, myo-inositol, 1-propanol, 2-phenylethanol), six organic acids (galacturonic, citric, lactic, malic, shikimic, succinic), three amino acids (alanine, proline, tyrosine), four sugars (arabinose, fructose, galactose, glucose), coutaric acid, and acetoin. The levels of these 22 components enabled the successful differentiation of young and mature wines among the three grape varieties. These findings underscore the substantial chemical distinctions between grape ales and wines, thereby emphasizing the potential of grape ales as an innovative fermented beverage. Full article

Hair straighteners are among the most technically complex products to be safely and effectively developed, and this challenge has increased even more with the higher incidence of resistant hair among consumers. This underscores the importance of studying new active ingredients, combinations and carrier formulations to improve performance without compromising safety. In this research, we compared eight hair-straightening formulations with different active ingredients and/or concentrations to develop new, safer and more effective texture modifiers. Eight formulations were developed and compared with each other and to controls (virgin and bleached hair) regarding mechanical and thermal resistance, cuticle morphology, hair shine and fiber diameter. Results showed that all formulations were safe and effective at straightening hair. Specifically, 13.3% and 9.4% ammonium thioglycolate (G03 and G04) were more suitable for wavy and curly hair, 12.5% and 7.9% amino methyl propanol thioglycolate (G05 and G06) for finer or chemically processed hair, 5% and 4% sodium cysteamine (G07 and G08) for curly and tight curly hair to control volume, and 2% and 1% of a combination of ammonium thioglycolate with sodium thioglycolate (G09 and G10) for more resistant wavy and curly hair. Full article

Traditional alkanolamine absorption methods for CO₂ capture suffer from significant absorbent loss and high regeneration energy consumption. To address this issue, novel blended alkanolamine formulations based on monoethanolamine (MEA), methyldiethanolamine (MDEA) and 2–amino–2–methyl–1–propanol (AMP) were investigated. Based on the optimization of CO₂ absorption conditions, a low–temperature and high–efficiency microwave heating desorption method for CO₂ was proposed, and the microwave heating desorption process of a CO₂ alkanolamine absorption solution was optimized. The results show that when the mass ratio of monoethanolamine (MEA), methyldiethanolamine (MDEA) and 2–amino–2-methyl–1–propanol (AMP) was 4:5:1, the composite alkanolamine solution with a concentration of 20% had the best absorption effect at an absorption temperature of 30 °C. The desorption efficiency of this group of formulations at 95 °C reached 89% in 4 min. Compared with the traditional heating desorption method, the CO₂ desorption rate of the microwave heating method at 95 °C increased by 62%, the desorption time was significantly shortened, and the energy consumption was significantly reduced. This study provides a new research direction for the efficient and low-energy desorption of CO₂ by blended alkanolamine. Full article

Absorption in amine solutions is a well-established advanced technology for CO₂ capture. However, the fundamental aspects of the chemical reactions occurring in solution still appear to be unclear. Our previous investigation of aqueous monoethanolamine (MEA) and 2-amino-2-methyl-1,3-propanediol (AMPD), based on ab initio molecular dynamics simulations aided with metadynamics, provided new insights into the reaction mechanisms leading to CO₂ capture and release with carbamate formation and dissociation. In particular, the role of water—strongly underestimated in previous computational studies—was established as essential in determining the development of all relevant reactions. In this article, we apply the same simulation protocol to other relevant primary amines, namely, a sterically hindered amine (2-amino-2-methyl-1-propanol (AMP)) and an aromatic amine (benzylamine (BZA)). We also discuss the case of CO₂ capture with the formation of bicarbonate. New information is thus obtained that extends our understanding. However, quantitative predictions obtained using molecular simulations suffer from several methodological problems, and comparison among different chemical species is especially demanding. We clarify these problems further with a discussion of previous attempts to explain the different behaviors of AMP and MEA using other types of models and computations. Full article

Here we present comparative studies of: (i) the formation of ZnO thin films via the sol-gel method using zinc acetate dihydrate (ZAD), 2-methoxyethanol (ME) as solvent, and the aminoalcohols (AA): ethanolamine, (S)-(+)-2-amino-1-propanol, (S)-(+)-2-amino-3-methyl-1-butanol, 2-aminophenol, and aminobenzyl alcohol, and (ii) elemental analyses, infrared spectroscopy, X-ray diffraction, scanning electron microscopy, absorption and emission spectra of films obtained after deposition by drop coating on glass surface, and thermal treatments at 300, 400, 500 and 600 °C. The results obtained provide conclusive evidences of the influence of the AA used (aliphatic vs. aromatic) on the ink stability (prior to deposition), and on the composition, structures, morphologies, and properties of films after calcination, in particular, those due to the different substituents, H, Me, or ⁱPr, and to the presence or the absence of a –CH₂ unit. Aliphatic films, more stable and purer than aromatic ones, contained the ZnO wurtzite form for all annealing temperatures, while the cubic sphalerite (zinc-blende) form was also detected after using aromatic AAs. Films having frayed fibers or quartered layers or uniform yarns evolved to “neuron-like” patterns. UV and photoluminescence studies revealed that these AAs also affect the optical band gap, the structural defects, and photo-optical properties of the films. Full article

In this work, perspective polymeric materials were developed for membrane contactor applications, e.g., for the dissolved oxygen removal from amine CO₂ capture solvents. Several polymeric blends based on poly[1-trimethylsilyl-1-propyne] (PTMSP) and poly[vinyltrimethylsilane] (PVTMS) were studied. The gas and water vapor sorption and permeability coefficients for the PTMSP/PVTMS blend membranes at different PVTMS contents (0–100%) were obtained under temperatures of 30 and 60 °C for the first time. As the PVTMS content increases, the O₂ and CO₂ permeabilities decrease by 160 and 195 times at 30 °C, respectively. The fractional accessible volume of the polymer blends decreases accordingly. The transport of the CO₂ capture solvent vapors through the PTMSP/PVTMS blend membranes were determined in thermo-pervaporation (TPV) mode using aqueous monoethanolamine (30%), N-methyldiethanolamine (40%), and 2-amino-2-methyl-1-propanol (30%) solutions as model amine solvents at 60 °C. The membranes demonstrated high pervaporation separation factors with respect to water, resulting in low amine losses. A joint analysis of the gas permeabilities and aqueous alkanolamine TPV data allowed us to conclude that the polymer blend composition of PTMSP/PVTMS 70/30 provides an optimal combination of a sufficiently high oxygen permeability and the pervaporation separation factor at a temperature of 60 °C. Full article

Both free and glycosidically bound forms of volatile compounds in Vidal grapes from the Shangri-La high-altitude region during the on-vine non-destructive dehydration process were investigated by headspace solid-phase micro-extraction (HS-SPME) combined with gas chromatography–mass spectrometry (GC-MS), following which the data were processed by multivariate statistical analysis. Fatty-acid-derived volatiles (FADs), amino-acid-derived volatiles (AADs), and isoprene-derived volatiles (IPDs), which occurred mainly in bound forms, were the three major volatiles in dehydrated Vidal grapes. Water-loss concentration, biosynthesis, and biodegradation all occurred during dehydration, eventually modifying some volatiles significantly, especially some powerful odorants such as hexanal, trans-2-hexenal, 2-phenethyl acetate, β-myrcene, linalool, geraniol, cis-rose oxide, and β-damascenone. 1-Octen-3-ol was relatively stable during the non-destructive on-vine dehydration process and its content in grape juice was mainly determined by the concentration effect. 2,4-Di-tert-butylphenol, 2-phenethyl acetate, 2-methyl-1-propanol, and hexanol were screened as some of the most important metabolic markers to discriminate grapes at different dehydration degrees. Our study also highlights the fundamental importance of the expression of volatile content in the metabolomic study of grape berries. Full article

CO₂ capture attracts significant research efforts in order to reduce the volume of greenhouse gases emitted from fossil fuels combustion. Among the studied processes, chemical absorption represents a mature approach and, in this direction, new solvents, alternatives to monoethanolamine (MEA), have been suggested. In this work, the solubility of CO₂ in aqueous solutions of 2-amino-2-methyl-1-propanol (AMP) and 3-(methylamino)propylamine (MAPA), which were recently suggested as constituents of novel phase change solvent mixtures, is experimentally measured at 298, 313, 323, and 333 K and in a wide range of pressures, up to approximately 7 bar. As the available literature experimental data for MAPA aqueous solutions are very limited, the experimental results of this study were compared to respective literature data for AMP, and a very satisfactory agreement was observed. The new experimental data were correlated with the cubic-plus-association (CPA) and the modified Kent-Eisenberg models. It was observed that both models rather satisfactorily correlate the experimental data, with the Kent-Eisenberg model presenting more accurate correlations. Full article

The yeast Yarrowia lipolytica is well known for its versatile production of metabolites from various substrates, but, although isolated from, e.g., wild-fermented Belgian Sour beers, it is rarely considered a starter culture in fermented beverages. In this study, we aimed to elucidate the ability of Y. lipolytica to ferment brewers’ wort containing iso-α-acid for 7 days at low and high aeration and at 20 °C and 30 °C, with a special focus on amino acid consumption and production of volatile aroma compounds. Y. lipolytica was able to grow in the wort under all four conditions, although the growth was inhibited. Furthermore, it only consumed glucose and fructose, and no ethanol was formed. Moreover, under high aeration conditions, Y. lipolytica consumed 75–80% of the amino acids in the wort. Interestingly, no esters were produced during the fermentations, and only five higher alcohols (1-propanol, 2-methyl-1-propanol, 3-methyl-1-butanol, 3-methyl-3-buten-1-ol, and 2-phenylethanol), two aldehydes (3-methylbutanal and (E)-2-nonenal), two ketones (cyclopentanone and 9-oxabicyclo [6.1.0]nonan-4-one), one fatty acid (3-methyl-butanoic acid), and one benzene derivate (1,2,4-trimethyl-benzene) were produced. These results may contribute to the potential use of Y. lipolytica in a traditional brewery for the production of novel beers; e.g., alcohol-free beer. Full article

The Paris Agreement and one of its goals, “carbon neutrality,” require intensive studies on CO₂ absorption and desorption processes. When searching for ways of reducing the huge energy cost of CO₂ desorption in the amine scrubbing process, the combination of blended amine with solid acid catalysts turned out to be a powerful solution in need of further investigation. In this study, the tri-solvent MEA (monoethanolamine) + EAE(2-(ethylamino)ethanol) + AMP(2-amino-2-methyl-1-propanol) was prepared at: 0.2 + 2 + 2, 0.5 + 2 + 2, 0.3 + 1.5 + 2.5 and 0.2 + 1 + 3 mol/L. The heterogeneous catalytic CO₂ desorptions were tested with five commercial catalysts: blended γ-Al₂O₃/H-ZSM-5, H-beta, H-mordenite, HND-8 and HND-580. Desorption experiments were conducted via a recirculation process with direct heating at 363 K or using temperature programming method having a range of 303–363 K. Then, the average CO₂ desorption rate, heat duty and desorption factors were studied. After comparison, the order of CO₂ desorption performance was found to be HND-8 > HND-580 > H-mordenite > Hβ > blended γ-Al₂O₃/H-ZSM-5 > no catalyst. Among the other combinations, the 0.2 + 1 + 3 mol/L MEA + EAE + AMP with HND-8 had a minimized heat duty (HD) of 589.3 kJ/mol CO₂ and the biggest desorption factor (DF) of 0.0277 × (10⁻³ mol CO₂)³/L² kJ min. This study provided a kind of tri-solvent with catalysts as an energy-efficient solution for CO₂ absorption and desorption in industrial CO₂ capture pilot plants. Full article

In this work, CO₂ absorption from simulated biogas is investigated using different blends of a PZ + AMP solution in an absorption system at CO₂ partial pressures ranging between 20 and 110 kPa. The collected data were presented as CO₂ removal profiles along the packed column and were evaluated in terms of CO₂ removal efficiency (%) and average overall volumetric mass transfer coefficient in the gas phase ($\overline{K_G{a}_v}$). An increased PZ concentration in the AMP solution was found to significantly increase the CO₂ removal efficiency and $\overline{K_G{a}_v}$ values. It was observed that, when conducted at different CO₂ partial pressures, gas and liquid flow rates, and chemical concentrations, the $L_{amine}/G_{C{O}_2}$ ratio strongly influenced the process behaviour in the packed column. Additionally, the optimal inlet liquid temperature was observed to be 35 ± 2 °C in this study. Full article

Three amino alcohols, 3-amino-1-propanol (abbreviated as 3a1pOH), 2-amino-1-butanol (2a1bOH), and 2-amino-2-methyl-1-propanol (2a2m1pOH), were reacted with quinoline-2-carboxylic acid, known as quinaldinic acid. This combination yielded three salts, (3a1pOHH)quin (1, 3a1pOHH⁺ = protonated 3-amino-1-propanol, quin⁻ = anion of quinaldinic acid), (2a1bOHH)quin (2, 2a1bOHH⁺ = protonated 2-amino-1-butanol), and (2a2m1pOHH)quin (3, 2a2m1pOHH⁺ = protonated 2-amino-2-methyl-1-propanol). The 2-amino-1-butanol and 2-amino-2-methyl-1-propanol systems produced two polymorphs each, labeled 2a/2b and 3a/3b, respectively. The compounds were characterized by X-ray structure analysis on single-crystal. The crystal structures of all consisted of protonated amino alcohols with NH₃⁺ moiety and quinaldinate anions with carboxylate moiety. The used amino alcohols contained one OH and one NH₂ functional group, both prone to participate in hydrogen bonding. Therefore, similar connectivity patterns were expected. This proved to be true to some extent as all structures contained the NH₃⁺∙∙∙⁻OOC heterosynthon. Nevertheless, different hydrogen bonding and π∙∙∙π stacking interactions were observed, leading to distinct connectivity motifs. The largest difference in hydrogen bonding occurred between polymorphs 3a and 3b, as they had only one heterosynton in common. Full article

There are a lot of research programs focusing on the development of new solvents for carbon dioxide capture. The most important priority should be reducing the energy consumption needed at the regeneration step, but minimizing solvent degradation and its corrosivity is also considered as a priority. In this research, the aqueous blends of 2-amino-2-methyl-1-propanol (AMP: 1 kmol·m⁻³) and 1-amino-2-propanol (MIPA: 0.1–0.5 kmol·m⁻³) are characterized in terms of density, viscosity, and surface tension. The carbon dioxide absorption rate and capacity, the regeneration capacity, and the corrosivity of these solvents are also evaluated. Full article

In order to select the best mixed amines in the CO₂ capture process, the absorption of CO₂ in mixed amines was explored at the required concentrations by using monoethanolamine (MEA) as a basic solvent, mixed with diisopropanolamine (DIPA), triethanolamine (TEA), 2-amino-2-methyl-1-propanol (AMP), and piperazine (PZ). Here, a bubble column was used as the scrubber, and a continuous operation was adopted. The Taguchi method was used for the experimental design. The conditional factors included the type of mixed amine (A), the ratio of the mixed amines (B), the liquid feed flow (C), the gas-flow rate (D), and the concentration of mixed amines (E). There were four levels, respectively, and a total of 16 experiments. The absorption efficiency (E_F), absorption rate (R_A), overall mass transfer coefficient (K_Ga), and scrubbing factor ($\varphi$) were used as indicators and were determined in a steady-state by the mass balance and two-film models. According to the Taguchi analysis, the importance of the parameters and the optimum conditions were obtained. In terms of the absorption efficiency (E_F), the absorption rate (absorption factor) (R_A/$\varphi$), and the overall mass transfer coefficient (K_Ga), the order of importance is D > E > A > B > C, D > E > C > B > A, and D > E > C > A > B, respectively, and the optimum conditions are A1B4C4D3E3, A1B3C4D4E2, A4B2C3D4E4, and A1B1C1D4E1. The optimum condition validation results showed that the optimal values of E_F, R_A, and K_Ga are 100%, 30.69 × 10⁻⁴ mol/s·L, 1.540 l/s, and 0.269, respectively. With regard to the selection of mixed amine, it was found that the mixed amine (MEA + AMP) performed the best in the CO₂ capture process. Full article