Effect Of Amine Structure Research Articles

Effect of amine properties on developing CO2 phase change absorbents by means of cosolvent effect

As China pledges that its carbon emissions will peak before 2030 and that it will be carbon neutral by 2060, the CO2 capture technology with high efficiency and low energy-consumption was expected in industry. CO2 phase change absorbents, CPCAs, had shown a potential to reduce energy consumption for CO2 capture. Although a lot of CPCAs were reported in the last decade, it still suffered from the lack of theoretical guidance for development. The effect of amine structure, which mainly affects cosolvent effect of amine and salting-out effect of formed salts, on developing CPCAs by means of cosolvent effect was clarified. For cosolvent effect of amine, 12 amines with various carbon chain lengths, isomers and substituents were determined by thermodynamical method and the log P of amine were proposed to characterize the cosolvent effect. The amine with long carbon chain and steric effect showed a high ability to act as a cosolvent to enhance the solubility of 1-butanol in H2O. The salting-out effect of formed salts by reacting amine and CO2 was related to pKa of amine. The absorbent comprising amine with low log P and high pKa was prefer to exhibit phase separation behavior, and benefit to develop CPCAs. Based on this guideline, all amines in this study could be developed as CPCAs by adjusting kinds of amine and diluent. Moreover, to explore the absorption-desorption performance of developed CPCAs, DEA/1-butanol/H2O was used as example, the volume ratio, species distributions and CO2 cyclic capacity were measured. When the absorption temperature was 303 K and desorption temperature was 373 K, The maximum CO2 cyclic capacity of CPCA was 2.03 mol CO2·kg−1, which was 34.4% higher than that of 30 wt% DEA/H2O.

Effect of amine structure on CO2 capture by polymeric membranes

Poly(amidoamine)s (PAMAMs) incorporated into a cross-linked poly(ethylene glycol) exhibited excellent CO2 separation properties over H2. However, the CO2 permeability should be increased for practical applications. Monoethanolamine (MEA) used as a CO2 determining agent in the current CO2 capture technology at demonstration scale was readily immobilized in poly(vinyl alcohol) (PVA) matrix by solvent casting of aqueous mixture of PVA and the amine. The resulting polymeric membranes can be self-standing with the thickness above 3 μm and the amine fraction less than 80 wt%. The gas permeation properties were examined at 40 °C and under 80% relative humidity. The CO2 separation performance increased with increase of the amine content in the polymeric membranes. When the amine fraction was 80 wt%, the CO2 permeability coefficient of MEA containing membrane was 604 barrer with CO2 selectivity of 58.5 over H2, which was much higher than the PAMAM membrane (83.7 barrer and 51.8, respectively) under the same operation conditions. On the other hand, ethylamine (EA) was also incorporated into PVA matrix to form a thin membrane. However, the resulting polymeric membranes exhibited slight CO2-selective gas permeation properties. The hydroxyl group of MEA was crucial for high CO2 separation performance.

Nitrosamines and Nitramines in Amine-Based Carbon Dioxide Capture Systems: Fundamentals, Engineering Implications, and Knowledge Gaps.

Amine-based absorption is the primary contender for postcombustion CO2 capture from fossil fuel-fired power plants. However, significant concerns have arisen regarding the formation and emission of toxic nitrosamine and nitramine byproducts from amine-based systems. This paper reviews the current knowledge regarding these byproducts in CO2 capture systems. In the absorber, flue gas NOx drives nitrosamine and nitramine formation after its dissolution into the amine solvent. The reaction mechanisms are reviewed based on CO2 capture literature as well as biological and atmospheric chemistry studies. In the desorber, nitrosamines are formed under high temperatures by amines reacting with nitrite (a hydrolysis product of NOx), but they can also thermally decompose following pseudo-first order kinetics. The effects of amine structure, primarily amine order, on nitrosamine formation and the corresponding mechanisms are discussed. Washwater units, although intended to control emissions from the absorber, can contribute to additional nitrosamine formation when accumulated amines react with residual NOx. Nitramines are much less studied than nitrosamines in CO2 capture systems. Mitigation strategies based on the reaction mechanisms in each unit of the CO2 capture systems are reviewed. Lastly, we highlight research needs in clarifying reaction mechanisms, developing analytical methods for both liquid and gas phases, and integrating different units to quantitatively predict the accumulation and emission of nitrosamines and nitramines.

Effect of amine structure on CO2 capture performance of amine-modified SBA-15

To investigate the relative CO2 capture performance of “molecular basket” type solid amine sorbents with varying amine structural characteristics, two model amine isomers, triethylenetetramine(TETA) and tris(2-aminoethyl)-amine(TAEA), were chosen alongside mesoporous silica SBA-15 as a support. The CO2 capture performance of each amine derivative was evaluated using a breakthrough method with a fixed-bed reactor. The results show that, in the absence of moisture, the SBA-TETA sorbents show better CO2 capture performance than the SBA-TAEA sorbents; on the other hand, in the presence of moisture, the SBA-TAEA sorbents show slightly improved uptake compared to the SBA-TETA sorbents. The tertiary amine groups, such as those found on TAEA, are known to be un-reactive with CO2 in the absence of moisture, but is activated in the presence of moisture may account for these findings.

Effect of Amine Structure on CO2 Adsorption of Modified Poly(ethyleneimine)-Impregnated Mesostructured Silica Sorbents

Abstract Poly(ethyleneimine) (PEI) was modified to study the effect of amine type and introduced hydroxy groups on its ability to capture carbon dioxide. Amines were impregnated in as-synthesized mesostructured silica (MSU-F) to fabricate solid amines, and the resulting samples were characterized via 13C nuclear magnetic resonance spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy. Nitrogen contents, structural properties, adsorption capacity, and sorbent durability during CO2 adsorption/desorption processes were measured to study the CO2 sorption performances of the sorbents. Reaction between PEI and propylene oxide (PO) altered the ratio of primary, secondary, and tertiary amines and also produced hydroxy groups on amine molecules. With a specific reactant ratio, a modified amine-impregnated sorbent (M-EP10) showed a CO2 adsorption capacity and amine efficiency of 13.90 wt % and 0.37, respectively, which were higher than that of the pristine PEI-impregnated sorbent. The new adsorbents also showed excellent stability in cyclic adsorption–desorption operations, even under pure CO2 desorption conditions in which commercial PEI adsorbents are known to lose CO2 adsorption capacity owing to urea formation.

Thin films exhibiting multicolor changes induced by formaldehyde-responsive release of anionic dyes

A novel methodology for the sensing of formaldehyde that displays a response using distinct and diverse color changes is reported. Through copolymerization of a primary amine monomer with additional co-monomers on a pattern-printed microscope slide, primary amine-containing thin films were obtained. After the absorption of a range of colors of anionic dyes, the thin films were immersed in aqueous formaldehyde solutions. It was demonstrated that the color of the thin films changed depending on the formaldehyde concentration in the solution. As the anionic dyes were released from the thin films at varying formaldehyde concentrations, a set of thin films exhibiting a range of color-change patterns was observed. The response selectivity of the thin films towards carbonyl compounds was examined, and sensitivity in the order of formaldehyde»acetaldehyde>acetone was observed. In addition, the effect of amine structure was examined, and it was found that thin films bearing tertiary amino groups show virtually no formaldehyde response. These observations clearly indicate that the existence of primary amino groups is essential for color changes to be observed, and that the formation of an imine is the crucial step in generating a response against formaldehyde. The formaldehyde-responsive system presented herein is advantageous, as its preparation is relatively simple and does not require complex organic synthesis. In addition, a wide range of anionic dyes is compatible with the system, and can be selected in terms of color, charge, toxicology profile, and cost, for example.

Effects of amine structure and base strength on acid–base cooperative aldol condensation

Aminated silica materials are known to efficiently catalyse aldol condensations, especially when silanol groups are neighbouring the amine function. The effect of the amine structure and base strength has been analysed experimentally and by kinetic modelling using commercially available precursors to graft primary, secondary and tertiary amines on the silica surface. While primary amines are arranged in a clustered manner on the catalyst surface, secondary amines are arranged randomly which results in a higher percentage of promoted amines in the low silanol-to-amine ratio range. An enamine compound formed by the reaction between the amine active site and acetone has been identified as the key intermediate to explain the experimental observations. In the case of a primary amine this enamine intermediate can form an inhibiting imine with which it is in equilibrium. As a secondary amine has only one hydrogen atom bonded to the nitrogen atom, the inhibiting imine cannot be formed, resulting in a comparatively higher concentration of reactive enamines on the catalyst surface. In case of a tertiary amine the formation of the reactive intermediate is impossible due to the absence of any hydrogen atom bonded to the nitrogen atom. The activation entropies of all reaction steps occurring on the amine sites, as obtained by regression, could be correlated to the deprotonation entropies of the amine sites. As the deprotonation enthalpy does not account for steric effects, no such correlation could be found between the activation energies of these reaction steps and the deprotonation enthalpies of the amine sites.

Effect of amine structure on CO2 adsorption over tetraethylenepentamine impregnated poly methyl methacrylate supports

Tetraethylenepentamine (TEPA) was modified by Michael addition reactions to study the effect of primary, secondary, and tertiary amine structure on its ability to absorb or desorb carbon dioxide. TEPA and modified TEPA were impregnated in a poly(methyl methacrylate) support to obtain solid amines. The specific characteristics such as pH, viscosity, and thermal stability were measured to study the properties of liquid amine. Structural properties, adsorption capacity, rate of adsorption, desorption energy, and sorbent durability during CO2 adsorption/desorption processes were measured to study the properties of solid amines.The pH of modified liquid TEPA (T1AN, T2AN, and T3AN) was slightly reduced; however, both viscosity and thermal stability were increased. The increased viscosity of the modified amines was indicative of an increase in attraction between the amine molecules; accordingly, amine leaching decreased noticeably and thermal stability of amines increased. Modified amine-impregnated sorbent (ST1AN and ST2AN) showed slight decrease in CO2 adsorption capacity but noticeable increase in rates of adsorption, durability during cyclic tests, and desorption characteristics compared to TEPA-impregnated sorbent (STEPA).

Polyurethanes from soybean oil, aromatic, and cycloaliphatic diamines by nonisocyanate route

AbstractPolyurethanes were prepared via a nonisocyanate route, by reacting carbonated soybean oil (CSBO) with aromatic and cycloaliphatic diamines. Nonisocyanate polyurethanes prepared form CSBO and aliphatic diamines have relatively low tensile strength and one of the possible ways to increase strength and rigidity is to use diamines with rigid aromatic or cyclic structure. The effect of amine structure and amine to carbonate ratio on polyurethane structure and mechanical, physical, and swelling properties was studied. m‐xylylene diamine (m‐XDA), p‐xylylene diamine (p‐XDA), and isophorone diamine were used as the reactants, with amine to carbonate ratios of 0.5 : 1, 1 : 1, and 1 : 2. All amines produced elastomeric polyurethanes with glass transitions between −6° C and 26°C, as measured by differential scanning calorimeter (DSC). Tg was primarily controlled by the amine‐to‐cyclic carbonate ratio, and to a lesser extent by the amine structure. The highest tensile strength was obtained for p‐XDA and the lowest for m‐XDA as a result of differences in hydrogen bonding. Tensile strength and hardness were higher than in aliphatic diamine‐based polyurethanes. Swelling in toluene and water depended on the polarity of polyurethane networks that was dominantly controlled by the amine‐to‐cyclic carbonate ratio. Swelling in toluene was higher at the lower amine to carbonate ratio due to lower polarity of the polyurethane matrix. Swelling in water behaved quite the opposite, the degree of swelling for the more polar polyurethane matrix was higher. Reaction temperatures of 70–100°C were high enough to promote ester group cleavage and along with urethanes, amide formation was always present. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Soy‐based polyurethanes by nonisocyanate route

AbstractPolyurethanes by a nonisocyanate route were prepared by reacting carbonated soybean oil with different diamines. The effect of amine structure and carbonate to amine ratio on polyurethane structure and mechanical, physical, and swelling properties was studied. The reactants 1,2‐ethylenediamine, 1,4‐butylenediamine, and 1,6‐hexamethylenediamine were used with the carbonate to amine ratio of 1 : 0.5, 1 : 1, and 1 : 2. It was found that along with urethane formation, the amine group reacted with ester groups to form amides. All amines produced elastomeric polyurethanes with glass transitions between 0 and 40°C and hardness between 40 and 90 Shore A. The reaction of epoxidized soybean oil with carbon dioxide was optimized resulting in complete conversion of epoxy to cyclic carbonate groups ending in polyurethanes with higher crosslinking density and much higher tensile strength than previously reported for similar polyurethanes. Swelling in toluene and water depended on crosslinking density and the polarity of polyurethane networks controlled by the cyclic carbonate‐to‐amine‐ratio. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Azulene‐substituted pyridines and pyridinium salts. Synthesis and structure. 2. Azulene‐substituted pyridinium salts

Abstractmagnified image4‐Azulen‐1‐yl substituted 2,6‐dimethyl‐and 2,6‐diphenyl‐pyridinium salts are obtained in yields between 50 % and 100 % in the reaction of corresponding 4‐azulen‐1‐yl‐pyranylim salts and various amines. The effects of amine structure and of substitution in the heterocycle or at azulene moieties on the synthesis have been investigated. The uv‐vis and NMR spectra of reaction products are examined and discussed in correlation with their structure.

Computational study of iminium ion formation: effects of amine structure

Density functional calculations are used to explore the formation of iminium ions from secondary amines and acrolein and the subsequent reactivity of the resulting iminium ions. After establishing a feasible profile for this reaction in simulated experimental conditions, we focus on the effect of variation in amine structure on calculated barriers. This analysis shows that incorporation of a heteroatom (N or O) in the alpha-position to the reactive amine results in significantly reduced energy barriers, as does an electron-withdrawing group (carbonyl or thiocarbonyl) in the beta-position. Electron density analysis is used to monitor reactions at a detailed level, and to identify important intermolecular interactions at both minima and transition states. Barriers to reaction are linked to calculated proton affinities of secondary amines, suggesting that the relative ease of protonation-deprotonation of the amine is a key property of effective catalysts. Moreover, barriers for subsequent Diels-Alder reaction of iminium ions with cyclopentadiene are lower than for their formation, suggesting that formation may be the rate determining step in the catalytic cycle.

Effect of Amine Structure on Photoreduction of Hydrogen Abstraction Initiators

The photocuring rates of acrylate monomers initiated by abstraction type photoinitiators (benzophenone, isopropylthioxanthone, and N-methylmaleimide) and a series of structurally different tertiary amine combinations are reported. Photo-DSC results confirm that transferable hydrogens on tertiary amines are essential for efficient acrylate polymerization. Laser flash photolysis experiments were carried out to define the electron/proton transfer reactions which occur between excited triplet states of the photoinitiators and tertiary amines. In the case of N-methylmaleimide, an intermediate radical anion was detected for amines with no readily transferable proton. This confirms that the photoreduction of the triplet state of N-substituted maleimides by tertiary amines occurs by an electron/proton transfer when the tertiary amine electron donor has a transferable proton.

ChemInform Abstract: Effect of Amine Structure and Reaction Additives on Enantioselective Deprotonations Mediated by Homochiral Magnesium Amide Bases.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Effect of amine structure and reaction additives on enantioselective deprotonations mediated by homochiral magnesium amide bases

A series of novel, optically pure, Mg-bisamides have been prepared and, in turn, used to mediate enantioselective deprotonations of conformationally locked ketones. The new bases exhibit a wide range of selectivities, from poor to excellent (up to 95:5 e.r.); trends between amine structure and the subsequent selectivity of the deprotonation system are detailed. In addition, the effects on the selectivity and the reactivity of the deprotonation process on replacing the Lewis base additive HMPA for DMPU have been investigated and found to be related to the reaction temperature.

Site—site interactions in a polymer matrix: effect of amine structure on transformations of copoly(styrene— p-nitrophenylacrylate)

Crosslinked copoly(styrene- p-nitrophenylacrylate)s ( 1a, 1b and 1c, containing 2, 4 and 10% divinylbenzene, respectively) reacted readily with secondary amines (piperidine, morpholine, piperazine, N-phenylpiperazine), the course of substitution being influenced by the crosslinking of 1, solvent polarity (dimethylformamide, methanol, toluene) and the structure of the amine. Steric interactions influenced the transformation of 1a with various primary amines (n-butylamine, i-propylamine and cyclohexylamine) giving the corresponding amides; tertbutylamine and aniline do not transform 1a under similar reaction conditions (dimethylformamide, ( T = 50°C). The swelling ability of the resins depended on the crosslinking of the starting copoly(styrene— p-nitrophenylacrylate) (bd1), the structure of the amide and solvent polarity (water, methanol, dimethylformamide, toluene, chloroform, cyclohexane).

Effect of amine structure on gallium extraction from hydrochloric acid solutions

The extractability of amine salts has been studied in a series of secondary amines-tertiary amines-quaternary ammonium salts while extracting gallium from hydrochloric acid solutions. The two- and single-parametric correlations obtained have revealed that the steric factor of the substituent attached to the nitrogen atom is not vital to the series of extractants studied. A change in the gallium extraction constant is determined by the induction effect (electronegativity) of substituents, thus the extractability of gallium with quaternary ammonium salts is the highest. Trialkyl amine was thus chosen as an extractant for the commercial applications of gallium extraction from complex acid solutions.

Effect of phosphate activating group on oligonucleotide formation on montmorillonite: the regioselective formation of 3',5'-linked oligoadenylates.

The effects of amine structure on the montmorillonite-catalyzed oligomerization of the 5'-phosphoramidates of adenosine are investigated. 4-Aminopyridine derivatives yielded oligoadenylates as long as dodecamers with a regioselectivity for 3',5'-phosphodiester bond formation averaging 88%. Linear and cyclic oligomers are obtained and no A5'ppA-containing products are detected. Oligomers as long as the hexanucleotide are obtained using 2-aminobenzimidazole as the activating group. A predominance of pA2'pA is detected in the dimer fraction along with cyclic 3',5'-trimer; no A5'ppA-containing oligomers were detected. Little or no oligomer formation was observed when morpholine, piperidine, pyrazole, 1,2,4-triazole, and 2-pyridone are used as phosphate-activating groups. The effects of the structure of the phosphate activating group on the oligomer structure and chain lengths are discussed.

Alkane-lnsoluble Trialkylammonium Double Salts Involving the Dodecamolybdophosphate Anion. II. Effect of Amine Structure on Third-Phase Formation

Abstract In this paper, a rational basis is presented for the control of molybdenum “third phase” formation in tertiary amine extraction through appropriate selection of amine structure. The studies have been founded on the observation that third-phase formation in the amine-extraction of molybdenum is mainly caused by the formation of heteropolymolybdates, especially the dodecamolybdophosphate anion PMo12O40 3− (DMP). Eight trialkylamine structures with straight and methyl -branched, 8-to 13-carbon chains have been examined with regard to the type of third phase formed and the maximum molarity of the dissolved salt (R3NH)3[DMP± that can be tolerated in the solvent before precipitation occurs (i.e., the DMP “tolerance”, a type of solubility measurement). In the experiments, a standard solvent consisting of 0.05 M tertiary amine (primarily as the trialkylammonium sulfate salt) and 0.15 M n-dodecanol in n-nonane was used. For all of the amines tested, third-phase formation first involved co-extraction of Mo...

Photochemical reactions of arenecarbonitriles with aliphatic amines. 2. Effect of amine structure on aminyl vs. .alpha.-aminoalkyl radical formation

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotochemical reactions of arenecarbonitriles with aliphatic amines. 2. Effect of amine structure on aminyl vs. .alpha.-aminoalkyl radical formationFrederick D. Lewis and Paul E. CorreaCite this: J. Am. Chem. Soc. 1984, 106, 1, 194–198Publication Date (Print):January 1, 1984Publication History Published online1 May 2002Published inissue 1 January 1984https://doi.org/10.1021/ja00313a039RIGHTS & PERMISSIONSArticle Views287Altmetric-Citations36LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (663 KB) Get e-Alerts Get e-Alerts