Amine Type Research Articles

Electrochemically Enabled, Nickel‐Catalyzed Amination

AbstractAlong with amide bond formation, Suzuki cross‐coupling, and reductive amination, the Buchwald–Hartwig–Ullmann‐type amination of aryl halides stands as one of the most employed reactions in modern medicinal chemistry. The work herein demonstrates the potential of utilizing electrochemistry to provide a complementary avenue to access such critical bonds using an inexpensive nickel catalyst under mild reaction conditions. Of note is the scalability, functional‐group tolerance, rapid rate, and the ability to employ a variety of aryl donors (Ar−Cl, Ar−Br, Ar−I, Ar−OTf), amine types (primary and secondary), and even alternative X−H donors (alcohols and amides).

Docetaxel-loaded nanostructured lipid carriers functionalized with trastuzumab (Herceptin) for HER2-positive breast cancer cells

The aim of the present study was to prepare Herceptin targeted nanostructured lipid carriers (NLCs) of docetaxel (DTX). Herceptin was conjugated by chemical and physical methods to NLCs prepared by solvent extraction technique followed by probe sonication. Different types of fatty amines were used in construction of NLCs. The NLCs were characterized for their antibody coupling efficiency, particle size, zeta potential, polydispersity index, drug entrapment efficiency and drug release profiles. The toxicity of NLCs on MDA-MB-468 (HER2 negative receptor) and BT-474 (HER2 positive) breast cancer cell lines was evaluated by MTT assay. Also their cellular uptake was studied by flow-cytometry and fluorescent microscopy. The results showed the NLCs containing stearyl amine had the lowest particle size, the highest zeta potential and antibody coupling efficiency values. Herceptin binding to NLCs led to reduction in zeta potential and drug entrapment efficiency while, particle size increased. The NLCs containing spermine(SP) released DTX slower than other fatty amines. Non-conjugated nanoparticles containing DTX had more toxicity than the free DTX on both cell lines. Herceptin targeted NLCs caused more mortality on BT-474 cells than MDA-MB-468 cells. Flow-cytometry studies revealed enhanced cellular uptake of nanoparticles chemically conjugated by Herceptin on the BT-474 cells. DTX loaded in chemically conjugated NLCs to Herceptin showed more cytotoxic effects than the physically coated nanoparticles. The Herceptin conjugated NLCs seem promising in oriented delivery of DTX to HER2 positive breast cancer cells.

Analysis of six aromatic amines stability in workplace measurement

For aromatic amine determination in workplaces, stabilities of six types of carcinogenic aromatic amines (2,4-diaminotoluene, 4,4'-diamino-3,3'-dimethyldiphenylmethane, o-tolidine, 3,3'-dichlorobenzidine, 4,4'-methylenebis(2-chloroaniline), and o-dianisidine) were evaluated with air or argon gas bubbling for 45 min in aqueous solution under light irradiation (desk lamp) and heating conditions. Gas chromatography–mass spectrometry (GC–MS) was used to identify and quantify the aromatic amines. The following conditions were selected: temperature program 70°C (1 min), 7 grad/min up to 120°C (1 min), 10 grad/min up to 300°C (5 min), carrier gas flow rate 1.0 mL/min. 3,3'-Dichlorobenzidine concentration decreased by approximately 10% after irradiation with a desk lamp for 45 min in distilled water, and a monochloro compound was detected by GC–MS. The other aromatic amines were rarely different from the 0-min concentration. The shielding prevented the decomposition of 3,3'-dichlorobenzidine in distilled water.

Controlled hydrogenation of diphenylacetylene using alkylammonium formate

A simple and straightforward semihydrogenation of alkyne to alkene with triethanolamine and formic acid in the presence of PdCl2has been described. Although hydrogenation using formic acid asa hydrogenation source has been used in combination with amines previously, few reports are available concerning the associated reactivity. We demonstrated that reactivity changes depending on the type of amine used in the hydrogenation. Further, this reaction requires no strict time control, making it a useful tool in organic synthesis.

Mesoporous silica impregnated with organoamines for post‐combustion CO2 capture: a comparison of introduced amine types

AbstractPolyethylenimine (PEI) with different molecular weight such as 275, 800, 1800, and 25000, together with tetraethylenpentamine (TEPA) were impregnated into a mesoporous silica support (silica gel) using a wet impregnation method. These resultant solid amine sorbents with different amine types were compared in terms of CO2 sorption kinetics and capacity at different temperatures, sorbent regeneration, and cyclic sorption‐desorption performance, to study the effect of introduced amine types on the CO2 capture performance. In the studied temperature range of 35–95°C for CO2 sorption, samples with different amine types perform differently in CO2 sorption kinetics and capacity. The largest CO2 capture capacity for different solid amine samples appears at different temperatures, and there is evident difference on CO2 capture capacity of different samples. In particular, PEI(25000)/silica gel showed the lowest CO2 capture capacity among all samples. Compared to PEI/silica gel samples, TEPA/silica gel showed a relatively higher CO2 sorption capacity. The regeneration of TEPA/silica gel is more difficult than PEI/silica gel samples, and 100°C was found suitable for complete regeneration of all sorbents. PEI(25000)/silica gel showed good reversibility and stability during 10 cyclic CO2 sorption‐desorption (sorption at 75°C and desorption at 100°C) tests, whereas PEI(275), PEI(800), PEI(1800), and TEPA/silica gel all suffered to various extents from amine leaching problems in cyclic CO2 sorption‐desorption performance under identical conditions. The cyclic CO2 sorption‐desorption performance can be improved by decreasing the desorption temperature to 75°C that leads to slightly loss of CO2 uptake in the second run. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd.

Preparation and Study of Shape Memory in Epoxy Resins

Shape memory polymers (SMPs) are stimuli‐response materials known for their ability to be actuated from temporary shape into original shape. Because of this unique functionality SMPs are promising materials for diverse applications fields, including smart biomedical devices, aviation, automobile, structures or coatings. In this article, the work has been focused on the chemical modification of an epoxy monomer Bisphenol A diglycidyl ether (DGEBA) which was carried out by using allyl amines as curing agents and a thiol. When both systems Epoxy‐Amine/Tiol‐Ene were photopolymerized, a soft phase is introduced through a thiol‐ene system and a rigid phase is given by the polymerization of the epoxy polymer when it reacts with the curing agent allyl amine. One of the main requirements in SMPs is the presence of soft and rigid phases. The study of the effect of the concentration of three different curing agents, allyl amine type, over the capacity of the conformed polymers to return to their original shape was evaluated. DMA analysis was used to determine the Tg in the polymers, once obtained, the polymers were treated on a hot water bath above 10 °C their Tg, then the evaluation of the memory shape was carried out by two tests, bending and torsion. SMPs were obtained and specimens with 20% of concentration of allyl amine as curing agent showed an improvement in their ability of memory shape with a 99% of recovery.

Rapid determination of histamine concentration in fish (Miichthys Miiuy) by surface-enhanced Raman spectroscopy and density functional theory

Histamine is a type of biogenic amine, which plays a major role in the health problems associated with seafood consumption. Legislative limits of histamine level in seafood have been set in many countries. This study focuses on investigating the feasibility and potentiality of determining histamine concentration in fish (Miichthys miiuy) by surface-enhanced Raman spectroscopy (SERS) combined with density functional theory (DFT). Both a gold colloid and a silver colloid were used to determine the enhancement effect for SERS detection of histamine standard solution, and the gold colloid exhibited more effective as compared to the silver colloid. The protocol on extraction of histamine with 12% trichloroacetic acid and adjustment of pH with NaOH solution (5 mol/L) could significantly shorten sample preparation (20 min) and provide clear SERS spectra of histamine. The peaks of histamine molecules were classified using the DFT and five spectra (953 cm-1, 992 cm-1, 1106 cm-1, 1262 cm-1 and 1317 cm-1) were selected as the characteristic bands of histamine discrimination. Moreover, the intensity of the peak at 1262 cm-1 had a good linear relationship with histamine concentration at 5-400 mg/kg with R2=0.9755. It is concluded that the SERS-DFT approach will be a potential method for rapidly and reliably detecting histamine at levels from 5 mg/kg to 400 mg/kg in fresh fish. Keywords: surface-enhanced Raman spectroscopy (SERS), density functional theory (DFT), gold nanoparticles, histamine, rapid determination, fish (Miichthys miiuy), food safety DOI: 10.25165/j.ijabe.20171004.3468 Citation: Chu B Q, Lin L, He Y. Rapid determination of histamine concentration in fish (Miichthys Miiuy) by surface-enhanced Raman spectroscopy and density functional theory. Int J Agric & Biol Eng, 2017; 10(4): 252–258.

Fabrication and CO2 permeation properties of amine-silica membranes using a variety of amine types

We developed a series of molecule-scale hybrid amine-silica membranes synthesized from organoalkoxysilane precursors of 3-(triethoxysilyl)propan-1-amine (PA-Si) and 3-(triethoxysilyl)-N-methylpropan-1-amine (SA-Si), and made these functional using either unhindered amines or a 3-(triethoxysilyl)-N,N-dimethylpropan-1-amine (TA-Si) that is sterically hindered. CO2 adsorption-desorption measurements of amine-silica powdered xerogels were conducted to observe the effect of amine type on CO2 adsorption and desorption/diffusion properties. The results revealed that TA-Si xerogel powders demonstrated faster kinetics for both adsorption and desorption processes compared with those of the PA-Si and SA-Si samples due to the steric hindrance effect of the amine, which reduced the CO2 binding energy and thereby boosted both the forward and reverse reaction rates of CO2-amine. In single-gas permeation performances, all the membranes exhibited excellent molecular sieving at higher temperatures and all the gases considered, except CO2, tended to permeate the membranes via activated diffusion. The effect of amine type on CO2 separation performance was compared using CO2 permeance, CO2/N2 selectivity, activation energy for permeation (Ep) of CO2 [Ep(CO2)], and differences in Ep between CO2 and N2 [Ep(CO2)-Ep(N2)]. The TA-Si membrane demonstrated superior CO2 separation performance, and achieved the highest values for both CO2 permeance and selectivity. A relatively smaller difference in CO2 separation performance was observed between PA-Si and SA-Si membranes despite some differences in basicity. This suggests that, rather than the basicity, it was the steric hindrance effect that played the greatest role in CO2 transport performance across amine-silica membranes.

Hierarchically Porous Sphere-Like Copper Oxide (HS-CuO) Nanocatalyzed Synthesis of Benzofuran Isomers with Anomalous Selectivity and Their Ideal Green Chemistry Metrics

Development of nanocatalysts for a chemical reaction with ideal values in green chemistry metrics is considered to be a challenging task to achieve sustainable chemistry. With this aim, we herein report a hierarchically porous sphere-like copper oxide (HS-CuO) nanocatalyst to afford benzofuranamine and dihydro-benzofuranamine isomers with anomalous selectivity via O-annulated A3 coupling among salicylaldehydes, secondary amines, and alkynes followed by cycloisomerization in the absence of base and solvent. The anomalous selectivity of benzofuran isomers was dependent on the electronic factors of substituents on salicylaldehyde and the type of secondary amines used in the coupling reaction. The HS-CuO nanocatalyst was recycled five times without significant loss in its catalytic activity. The present method offers several advantages over the reported methods such as wide substrate scope with anomalous selectivity in the products, high yields in short reaction time, avoided the usage of extra reagents such as additives/bases, and showed ideal values of green chemistry metrics such as low E-factor and process mass intensity (PMI), high atom economy (AE), reaction mass efficiency (RME), and carbon efficiency (CE).

Investigation of mass transfer coefficient of CO2 absorption into amine solutions in hollow fiber membrane contactor

In this work, the CO2 absorption performance in aqueous amine solutions have been investigated in hollow fiber membrane contactor. The overall mass transfer coefficients (Kol) was evaluated at different operating conditions, including absorbent type, liquid velocity, gas velocity and concentration of amine. The experimental results reveal that the overall mass transfer coefficient increase with liquid velocity, gas velocity and concentration of amine increasing. DEEA, as a promising tertiary amine, has a higher Kol value compared to that of MDEA.

Novel Green Solvents for CO2 Capture

This study investigates the viability of novel green solvents for carbon capture. Three different types of amine based deep eutectic solvents were synthesized at three different molar ratio. The selected amines represent the primary (monoethanolamine), secondary (diethanolamine) and tertiary (methyldiethanolamine) amines, respectively. The CO2 absorption was conducted with a solvent screening set-up (SSS) and the CO2 loading was measured with an ‘Elementar’ total organic carbon (TOC) analyzer. Thereafter, FTIR of the samples was conducted in order to determine the qualitative analysis for tracking the appearance, disappearance and stability of different functional groups (400-1600 cm-1). The solubility experiments were performed based on the conditions of the absorber in the post-combustion capture process (PCO2 = 15kPa and T = 40oC). Results revealed that amine-based DESs have absorption capacity that is much higher than both 30wt% aqueous amine solutions and conventional DESs. The FTIR broadening of the O–H and N–H stretching of MEA and ChCl individual components, indicates the formation of hydrogen bonds between the two of them in the ChCl-MEA 1:6 before CO2 absorption.

Non-isothermal cure and decomposition kinetics of epoxy–imidazole systems

Non-isothermal curing kinetics of a tetra functional epoxy resin with imidazole-based curing agents was investigated by differential scanning calorimetry (DSC), and decomposition of the cured compounds was studied by thermogravimetric analysis. N,N,N′,N′-tetraglycidyl-4, 4′diaminodiphenylmethane (TGDDM) was cured with three types of tertiary amine curing agents including 1-methyl imidazole (MI), 2-methyl imidazole (2MI) and 2-ethyl 4-methyl imidazole (EMI). These systems exhibited cure initiation at around 70–90 °C by DSC. 2-methyl imidazole and 2-ethyl 4-methyl imidazole showed two cure initiation profiles, while the 1-substituted counterpart, MI, showed a single cure initiation profile by DSC. The Kissinger equation was applied to calculate the apparent activation energy for epoxy–imidazole cure reactions. The rate constants and the pre-exponential factor were also determined. The activation energy varied from 59 to 65 kJ mol−1 for the systems. The Flynn–Wall–Ozawa iso-conversional approach was used to elucidate the activation energies at different extents of conversion during the cure reactions. The cured systems are found thermally stable up to 250 °C. Decomposition kinetics of cured networks was studied using Kissinger equation and Flynn–Wall–Ozawa iso-conversional approach. The cured resins were analyzed for the glass transition temperature and compared with that of a conventional amine-cured system.

Development of phase separation solvent for CO2 capture by aqueous (amine + ether) solution

Phase separation solvents for CO2 absorption have been designed which transform into two liquid phases after CO2 absorption. We studied seven types of amines and one type of ether-mixed solvents and observed that there are three types of phase phenomena, namely, no phase separation, phase separation with CO2 scrubbing, and initially immiscible. We also observed that these types can be classified using the hydrophobicity of the amine. The solubility of CO2 was measured in the phase separation solvent. In the lower-pressure region, the solvent formed a single liquid phase. When the amount of CO2 in solution reached a separation point, the solvent separated into two liquid phases.

Development of membrane contactors using volatile amine-based absorbents for CO2 capture: Amine permeation through the membrane

Non-porous membrane contactor offers the possibility to reduce the amine emissions if the membrane layer is specifically designed to act as a barrier for the amine transport. In the present paper, the amine permeation through an AF2400 self-standing membrane, previously identified as the best dense layer material, have been investigated to evaluate the amine-emission preventing capacity of the membrane for the first time. The transport properties of different amine-based aqueous solutions (monoethanolamine, 3-methylaminopropylamine and diethylethanolamine) through a 10µm-thick self-standing AF2400 membrane have been characterized through pervaporation experiments in a temperature range of a typical amine absorption step (25–60ºC). Humid CO2 permeation tests were also carried out to simulate the real gas membrane absorption separation conditions. A limited decrease (up to 25%) of the CO2 permeability was observed from dry state to fully humidified conditions, suggesting that the membrane contactor can be operated with humid flue gas to prevent solvent dehydration. The amine fluxes were found at least two orders of magnitude lower compared with CO2, demonstrating the ability of the membrane to favor the transport of CO2 over the amines.

Pd-Catalyzed Acyl C-O Bond Activation for Selective Ring-Opening of α-Methylene-β-lactones with Amines.

A Pd-catalyzed ring-opening of β-lactones with various types of amines (primary, secondary, and aryl) to provide β-hydroxy amides with excellent selectivity toward acyl C-O bond cleavage is reported. The utility of this protocol is demonstrated in an asymmetric kinetic resolution providing enantioenriched α-methylene-β-lactones.

Influence of amine groups in the chemical structure of photochromic dyes on the rheological and mechanical properties of poly(methyl methacrylate) (PMMA)

Polymer modification has been used as a means to improve the adhesion/bonding of compounds and/or particles to polymer chains, but this goal is not always achieved. Some compounds contain naturally reactive groups which, in contact with the polymer, can modify its properties. This work focused on the rheological (torque and parallel plates rheometry) and mechanical (tensile and impact) characterization of PMMA containing the DV31, DBL3 and DB79 aminic dyes and the DR73 inert dye. The rheological results indicated that the final torque (torque rheometry) varied in response to increasing dye concentrations, and that the various dyes under study exhibited distinct behaviors (parallel plates rheometry). The mechanical tests revealed that, overall, the effect of the dyes on the properties of PMMA was negligible, except for DV31, that led to the decrease in the impact strength, possibly due to the bond between chains or segments of chains of the polymer. The presence, amount and type of amine in the dyes gave rise to significant rheological changes in PMMA because of the reactivity between the amine and the ether group of PMMA.

Effect of Type of Amine Salt and Surfactant on the Water Sorption and Flexural Properties of Modified Zeolite/Polyester Composites

Natural zeolite, an abundant clay with porous solids based on silica, is modified with amine salt and surfactant, and incorporated as filler for polyester to produce modified zeolite/polyester (MZP) composite. A general factorial design of experiment is implemented with two factors (type of amine salt and type of surfactant) varied at three levels each. The amine salts are tetra- (TDA), hexa-, and octadecyl dimethylamine chloride while surfactants are stearic acid (SA), glycerol monostearate, and cocamide diethanolamine (CDEA). Water sorption and flexural testing are performed on MZPs. Results show that natural zeolite treated with SA exhibits improved hydrophobicity of MZPs, resulting to lower water uptake as compared to untreated natural zeolite. However, water sorption in MZPs is higher than in pure polyester due to difference in hydrophobicity. Flexural modulus of MZP is highest using TDA + CDEA due to enhanced filler-to-matrix compatibility. Meanwhile, break stress is highest for untreated zeolite filler due to the high stress resistance of rigid natural zeolite. Analysis of variance shows water sorption to be significantly affected by the type of surfactant, while break stress is significantly higher using amine salt with shorter chain length.

Reactions of Secondary Amines with Bis(η5:η1-pentafulvene)titanium Complexes: Formation of Titanium Amides and Titanaaziridines

The reactions of bis(η5:η1-pentafulvene)titanium complexes (1) with 19 different secondary amines (Aa–s) have been investigated. Depending on the substitution pattern of 1 and nature of the amine used, different reaction products are formed. With use of bis(η5:η1-di(p-tolyl)pentafulvene)titanium (1b) and N-methylanilines (Aa,b), N-methylbenzylamines (Ac,d), N-methylcyclohexylamine (Ae), and dibenzylamine (Af), titanium monoamides of the type (η5-C5H4CH(p-tolyl)2)(η5:η1-C5H4═C(p-tolyl)2TiNR2 (2a–f) have been isolated in high yields and characterized, including by single-crystal X-ray diffraction. By the reactions of bis(η5:η1-adamantylidene)titanium (1a) and Af, diethylamine (Ag), and 2-methylpiperidine (Ah) similar monoamides 3f–h are formed. The formation of titanium bis-amides employing different types of secondary amines (Aa–s) is not observed. The formation of titanaaziridines is observed exclusively by using 1a and N-methylanilines (Aa,b), N-benzylphenylamine (Ai), and N-benzyltrimethylsilylamines (A...

Molecular Dynamic Simulation of Amine-CO2 Absorption Process

Objectives: Modelling and simulation of amine absorption process for CO2 removal at macro-scale is well established. This study used to investigate the amine-CO2 absorption process at molecular level using Molecular Dynamic (MD) simulation. Methods/Statistical Analysis: Analysis on different types of amine and blended amines for absorption process was conducted in this study. COMPASS and Ewald models used for force field and summation method calculation, respectively. Findings: The results shows MEA solvent was the highest tendency (39.70%) to interact with CO2 compared to DEA and MDEA because can directly react with CO2 and easily form carbamate ions. Due to the lack of –HN bond in MDEA, it was determined to be less reactive and suggested to be blended with other reactive amines. Blended MDEA/AMP (33.50%) and MDEA/PZ (23.80%) improved the efficiency of MDEA in CO2 absorption process. The addition of AMP and PZ assisted MDEA to have intermolecular interaction with CO2. Application/Improvements: Research on molecular modelling of amine absorption process for CO2 capture was proposed in this study to give insight about this process at molecular level and to analyse the intermolecular interaction between CO2 and amine solution.

Regioselective Construction of α,α-Disubstituted Allylic Amines by the Ruthenium-Catalyzed Allylic Amination of Tertiary Allylic Acetates.

The ruthenium-catalyzed regioselective allylic amination of tertiary allylic acetates with several types of amines has been accomplished. The reaction was effectively catalyzed by Cp*RuCl2/5,5'-dimethyl-2,2'-bipyridine or its related ruthenium catalyst systems, and α,α-disubstituted allylic amines were formed as a single regioisomer in moderate to high yields.