N-methylethanolamine Research Articles

Performance assessment of alko-amine corrosion inhibitors for use as an admixture in reinforced concrete structures: Experimental investigation and mechanism of action

Corrosion in reinforced concrete (RC) is a major issue in the construction industry, giving rise to structural failure, huge repair costs, and safety concerns. To mitigate RC corrosion, chemical corrosion inhibitors (CCI) are commonly used. This study aims to investigate the performance of different alko-amine CCIs for corrosion control in reinforced concrete (RC) structures subjected to chloride-rich conditions. The experimental program was divided into two levels: investigations comprised of quick testing on bare rebars, suitable for industries, and analysis which comprised of electrochemical investigation in simulated concrete pore solution and testing on rebar embedded in concrete, suitable for research labs. The interaction between inhibitors and steel was examined through surface analytical techniques such as AFM and XPS. Finally, the inhibition mechanism for the CCI was proposed. The alko-amines were found to show a strong dependence on their molecular structure for the formed film integrity. Monoethanolamine (MEA) and methyl ethanolamine (MeEA) formed a denser and more uniform film compared to dimethyl ethanolamine (DMeEA) and ethyl monoethanolamine (EMEA). MeEA showed the highest inhibition efficiency in both simulated pore solution environments and when used as an admixture in RC.

Comprehensive evaluation of physical properties and carbon dioxide capacities of new 2-(butylamino)ethanol-based deep eutectic solvents

Abstract The aim of this research was to assess the impact of the components of alkanolamine deep eutectic solvents (DESs) on the physical properties of those DESs and their carbon dioxide capacity. To achieve this goal, novel deep eutectic solvents were synthesized by using 2-(butylamino)ethanol (BAE) as the hydrogen bond donor (HBD), along with tetrabutylammonium bromide TBAB), tetrabutylammonium chloride (TBAC), or tetraethylammonium chloride (TEAC) as the hydrogen bond acceptors (HBA) at various molar ratios (1:6, 1:8, and 1:10). To confirm the presence of hydrogen bond interactions between the components Fourier Transform Infrared Spectroscopy measurements were conducted. Furthermore, thermal properties, including melting points and thermal stability, of these deep eutectic solvents as well as key physical properties, such as density, viscosity, refractive index, and sound velocity, within the temperature range of 293.15–333.15 K and at a pressure of 0.1 MPa were examined. The effect of the molar ratio of HBA to HBD, the type of anion, and the length of the alkyl chain were studied and analysed in regard to physicochemical properties. In this work, the solubility of carbon dioxide in DESs derived from 2-(butylamino)ethanol, 3-aminopropan-1-ol (AP), and 2-(methylamino)ethanol (MAE) was measured. The highest CO2 capacity was found for TEAC:MAE 1:10 DES characterized by the shortest alkyl chain length in both HBA and HBD molecules, the highest amine content, and the lowest viscosity. Additionally, the effect of water addition on carbon dioxide solubility was explored. The results showed that the influence of water on CO2 solubility varies with the type of DES. In general, this work highlighted that DESs can serve as effective media for carbon dioxide capture, and their performance can be tailored by changing the type of hydrogen bond acceptor or donor, their molar ratio and by the addition of water.

Revealing the potential of cyclic amine morpholine (MOR) for CO2 capture through a comprehensive evaluation framework and rapid screening experiments

The present study comprehensively evaluates the CO2 capture performance of morpholine (MOR) at concentrations of 2 M, 5 M, and 7 M, comparing its effectiveness against conventional amines, monoethanolamine (MEA) and 2-(methylamino)ethanol (MAE). The assessment criteria include CO2 absorption rate, desorption rate, cyclic capacity, regeneration energy consumption, and relative economic cost. Utilizing 13C Nuclear Magnetic Resonance (NMR) technology, we analyzed the variations in ion concentration of the amine solvents under different CO2 loadings to reveal the reaction mechanisms of MOR with CO2. Our results demonstrate that MOR outperforms MEA and MAE in CO2 capture performance, particularly excelling in desorption efficiency. At a concentration of 7 M, MOR exhibited a 357.86% increase in average desorption rate and a 46% larger cyclic capacity compared to MEA. Additionally, MOR showed a 33.33% reduction in regeneration energy consumption and a 7.89% decrease in relative economic cost. The comprehensive evaluation method developed in this study indicates that MOR, with its high thermal stability and low corrosivity, maintains excellent CO2 capture performance at high amine concentrations, suggesting it as a promising absorbent for industrial applications. The findings contribute to the optimization of amine-based CO2 capture technologies and provide a robust framework for the selection and assessment of amine solvents, paving the way for more sustainable and cost-effective carbon capture solutions.

Amine-based CO2 capture on-board of marine ships: A comparison between MEA and MDEA/PZ aqueous solvents

International maritime shipping contributed nearly 3 % of global CO2eq emissions in 2018. The IMO has set an ambition to reach net zero CO2 emissions from maritime activities by 2050 with checkpoints of 40 % reduction by 2030 and 70 % by 2040 compared to 2008 baseline levels. In addition to alternative fuels (LNG, biofuel, methanol, hydrogen, ammonia) and efficiency-based technologies, mobile carbon capture (MCC, called also ship-borne/based carbon capture SBCC) could become a plausible technology to help meet these decarbonization aspirations. In this work, we performed a simulation to compare the use of methyl-ethanolamine (MEA) and methyl-di-ethanolamine/piperazine (MDEA/PZ) aqueous mixtures for chemical temperature swing separation of CO2 on-board a ship. We studied the main MCC system integration and design parameters and demonstrated that MDEA/PZ could represent a more efficient and cheaper path than MEA due to the heat availability limitations from the exhaust stream of the ship. Specifically, MDEA/PZ could enable 10 % savings in heat demand at the reboiler compared to MEA (3.3 vs 3.7 GJ/tCO2). Additionally, we showed that an MDEA/PZ amine-based CO2 capture and storage unit on-board the ship could lead to as low as 191$/ton CO2 avoided compared to 281$/ton of CO2 when using MEA

Hybrid behaviors of CO2 absorption into blended DEEA‐based solution for the improvement of capture performance

AbstractBACKGROUNDAt present, the chemical absorption method of CO2 capture is considered to be an effective means to reduce carbon emissions. The development of blended amine systems with excellent CO2 capture performance is the focus of research.RESULTThe hybrid behaviors of N,N‐diethylethanolamine (DEEA) with addition of monoethanolamine (MEA), 2‐(methylamino)ethanol(MAE) and 2‐((2‐aminoethyl)amino)‐ethanol(AEEA) as absorbents were investigated and developed to reduce the energy consumption for solvent regeneration in the CO2 capture process. The equilibrium solubility of CO2 for blended DEEA/MEA, DEEA/MAE and DEEA/AEEA with a series of molar ratios (0.0:2.0, 0.5:1.5, 1.0:1.0, 1.5:0.5 and 2.0:0.0) was examined. The experimental results showed that the values of CO2 equilibrium solubility of amine blends exhibited a compromise behavior between each individual amine solution. Additionally, the effects of molar ratios on the relative CO2 absorption rate, regeneration rate and CO2 cyclic capacity for the tested amine blends were studied using an improved rapid absorbent screening method.CONCLUSIONThe experimental data showed that the blended DEEA/MAE solution exhibits much higher CO2 cyclic capacity than that of DEEA/AEEA under the nitrogen atomic conservation. However, the mixing DEEA and AEEA could obviously reduce the CO2 equilibrium solubility and CO2 cyclic capacity compared with that of individual AEEA solution, indicating the DEEA had an inhibiting effect on AEEA. Furthermore, the mass transfer performances of DEEA, DEEA/MAE and DEEA/AEEA were tested in order to validate the accuracy of the improved rapid absorbent screening method. © 2024 Society of Chemical Industry (SCI).

A low energy-consuming phase change absorbent of MAE/DGM/H2O for CO2 capture

The concept of phase change absorbents has been widely studied as a novel and low-energy consumption option for CO2 capture. This work screened diethylene glycol dimethyl ether (DGM) from 17 physical solvent species as a better phase change accelerator for absorbents of 2-(methylamino)ethanol (MAE)-physical solvent-H2O. Then, the optimized mass ratio of 30:49:21 for MAE-DGM-H2O solution was investigated with phase change behaviors, CO2 absorption–desorption performance, cyclic capacity, and energy consumption. The experimental results showed that the cyclic CO2 capacity reached 1.32 mol/L and the CO2-rich phase made up only 50.4 % of the total volume for the 30 wt%MAE-49 wt%DGM-21 wt%H2O, as well as its regenerative energy consumption was 40 % lower than that of 30 wt% monoethanolamine (MEA) solution. Also, the viscosity and surface tension gap of the CO2-rich phase and CO2-lean phase for the optimized absorbent were studied. It was observed that those gaps increase with the increasing mass ratio of DGM. In addition, the possible phase change mechanism was proposed by using the dipole moment values of components calculated by Gaussian (B3LYP/6-31G) coupled with 13C NMR spectra.

Redox Chemistry of Pt(II) Complex with Non-Innocent NHC Bis(Phenolate) Pincer Ligand: Electrochemical, Spectroscopic, and Computational Aspects

A Pt(II) complex bearing chelating tridentate bis-aryloxide tetrahydropyrimidinium-based N-heterocyclic carbene (NHC) was synthesized and characterized by using different techniques. Both cyclic voltammetry and differential pulse voltammetry were used to study the electrochemical properties of the complex, revealing two reversible one-electron oxidation processes. The chemical generation and isolation of one-electron-oxidized species were performed oxidizing the initial complex by means of AgBF4. A combination of spectroscopic (UV-Vis/NIR- and EPR-) and theoretical (density functional theory (DFT)) studies suggests the formation of a Pt(II)-phenoxyl radical complex. The latter open-shell derivative was structurally characterized by means of X-ray diffraction analysis. Finally, the neutral platinum complex was tested as a mediator in the process of electrocatalytic oxidation of 2-(methylamino)ethanol (MEA).

An experimental and theoretical study on the effects of amine chain length on CO2 absorption performance

AbstractTo explore the effect of amine chain length on CO2 absorption performance, the reaction kinetics of CO2 absorption in aqueous 1‐dimethylamino‐2‐propanol (DMA2P), 1‐diethylamino‐2‐propanol (DEA2P), 2‐(methylamino)ethanol (MAE), and 2‐(ethylamino)ethanol (EAE) solutions with different concentrations were explored using the stopped‐flow apparatus. Additionally, Density Functional Theory (DFT) calculations were conducted to examine the reaction mechanism and the free energy barrier of the elementary reactions underlying CO2 absorption in these four aqueous amine solutions. Kinetic models for CO2 absorption in tertiary amines and secondary amines were established, based on the base‐catalyzed hydration mechanism and the zwitterion mechanism, respectively, both of which perform well in predicting the relationship between k0 and the amine concentration. The free energy barrier obtained by DFT is consistent with the activation energy barrier trend obtained by experiment. In addition, the effect of chain length on the free energy barrier was investigated through the chemical bond and weak interaction analysis.

Novel dental resin infiltrant containing smart monomer dodecylmethylaminoethyl methacrylate.

White spot lesions (WSLs) are prevalent and often lead to aesthetic problems and progressive caries. The objectives of this study were to: (1) develop a novel resin infiltrant containing smart monomer dodecylmethylaminoethyl methacrylate (DMAEM) to inhibit WSLs, and (2) investigate the effects of DMAEM incorporation on cytotoxicity, mechanical properties, biofilm-inhibition and protection of enamel hardness for the first time. DMAEM was synthesized using 1-bromododecane, 2-methylamino ethanol and methylmethacrylate. DMAEM with mass fractions of 0%, 1.25%, 2.5% and 5% were incorporated into a resin infiltant containing BisGMA and TEGDMA. Cytotoxicity, mechanical properties and antibacterial effects were tested. After resin infiltration, bovine enamel was demineralized with saliva biofilm acids, and enamel hardness was measured. DMAEM infiltration did not increase the cytotoxicity or compromise the physical properties when DMAEM mass fraction was below 5% (p > 0.05). Biofilm metabolic activity was reduced by 90%, and biofilm lactic acid production was reduced by 92%, via DMAEM (p < 0.05). Mutans streptococci biofilm CFU was reduced by 3 logs (p < 0.05). When demineralized in acid and then under biofilms, the infiltrant + 5% DMAEM group produced an enamel hardness (mean ± sd; n = 6) of 2.90 ± 0.06 GPa, much higher than 0.85 ± 0.12 GPa of the infiltrant + 0% DMAEM group (p < 0.05). A novel resin infiltrant with excellent mechanical properties, biocompability, strong antibacterial activity and anti-demineralization effect was developed using DMAEM for the first time. The DMAEM resin infiltrant is promising for inhibiting WSLs, arresting early caries, and protecting enamel hardness.

Nonaqueous (amine + glycol ether) solvents for energy-efficient CO2 capture: New insights into phase change behaviors and assessment of capture performance

Nonaqueous amine-based absorbents, particularly liquid biphasic solvents, have recently received increasing attention due to the potential for reducing the energy penalty of CO2 capture. In this work, a series of glycol ethers were used as cosolvents dissolving primary and secondary alkanolamines. Phase transition behavior, CO2 absorption and desorption characteristics have been investigated for the nonaqueous 5.0 M amine blends. Different phase behaviors upon CO2 absorption were discussed and well explained by the polarity change and the solubility parameter interaction distance (SPID) of components and the reaction products. Regeneration energy requirement was also experimentally estimated and compared with the reference aqueous monoethanolamine (MEA). The species in the CO2-loaded solution play a central role in regulating phase separation behaviour and CO2 capture performance. A defined SPID value was recommended to predict the monophasic and the biphasic states. Advanced systems of 2-(methylamino)ethanol (MAE) with diethylene glycol dimethyl ether (DEGDME) as liquid biphasic solvent and MAE with ethylene glycol monomethyl ether (EGME) as single phase solvent were proposed for energy-efficient CO2 capture. Among the systems investigated, MAE/EGME has the lowest regeneration energy consumption estimated at about 1.75 MJ kg−1 CO2 captured. The ionic carbonated products of alkanolamines can trigger the phase change behaviour due to their limited solubility in the more hydrophobic and weakly polar DEGDME, resulting in two opposite phases enriched in different components. Benefiting from the high enrichment (>95 %) of CO2 captured in the lower phase and the large cyclic capacity, MAE/DEGDME biphasic solvent can reduce the energy consumption by 50–59 % compared with aqueous MEA.

Novel alkanolamine-based biphasic solvent for CO2 capture with low energy consumption and phase change mechanism analysis

Biphasic solvents for CO2 capture have received significant attention due to their potential for energy conservation. However, traditional biphasic solvents result in highly viscous CO2 rich-phases and high amine losses. To overcome these drawbacks, we have developed a novel alkanolamine-based biphasic solvent by blending 2-(methylamino) ethanol (MAE), 3-(dimethylamino)propan-1-ol (3DMA1P), diethylene glycol dimethyl ether (DGM), and water. The aqueous MAE/3DMA1P/DGM solvent showed a cyclic capacity of 0.45 mol CO2/mol amine, which is 1.8 times that of monoethanolamine (MEA), and a desorption rate and regeneration efficiency twice those of MEA. The viscosity of the biphasic solvents can be reduced to 13.12 mPa⋅s at 313 K, which is lower than that of reported biphasic solvents. The evaluated regeneration energy was 2.33 GJ/ton CO2. Cation chromatography measurements revealed the tendency of MAE to accumulate in the CO2-rich phase with increasing CO2 absorption loading. Quantitative 13C NMR analyses were performed to investigate the species distribution in both phases, and DGM was found to be the major component of the CO2-lean phase. Different solubilities of the MAE molecules and MAE carbamate in DGM resulted in phase separation. Molecular dynamics (MD) simulations on the CO2-unloaded and CO2-loaded solutions verified the phase separation mechanism. MAE molecules tended to cluster, and the interactions between MAE and DGM dropped significantly, with increasing DGM concentration.

Furthering the understanding of product formation in monoethanolamine degradation: A mechanistic DFT study

A thorough understanding of the product formation originating during degradation of monoethanolamine is crucial to future commercialization of carbon capture plants. Here we report on a series of density functional theory (DFT) calculations outlining chemical pathways for the formation of oxidative degradation products. Fragmentation of monoethanolamine (MEA) radicals is surmountable given standard experimental conditions and can lead to the formation of ethanal, ethanoic acid, ammonia, methylamine, water, formaldehyde, formic acid and imines. Alternatively, the MEA radicals can form hydroperoxides after reaction with oxygen which can subsequently go on to form glycine, glycolic acid and N-(2-hydroxyethyl)glycine (HEGly). Experimentally surmountable routes to the formation of oxazoline, N-(2-hydroxethyl)ethylenediamine (HEEDA), N,N’-bis(2-hydroxyethyl)ethylenediamine (BHEEDA), epoxides, (2-Methylamino)ethanol (MAE), N-(2-hydroxyethyl)imidazole (HEI) and diethanolamine (DEA) are also presented.

Neorhizobium xiangyangii sp. nov., isolated from a highland barley cultivation soil in Qamdo, Tibet.

A novel Gram-negative, aerobic, rod-shaped and non-nitrogen fixing bacterium named T786T was isolated from a highland barley cultivation soil in Qamdo, Tibet Autonomous Region, PR China. Strain T786T grew at 5-30℃ and pH 6.0-10.0 (optimum, 20-25℃ and pH 7.0-8.0) with 0-4% (w/v) NaCl (optimum, 0%). The 16S rRNA gene sequences of strain T786T showed the highest similarity to Neorhizobium vignae CCBAU 05176T (98.7%), followed by Neorhizobium alkalisoli CCBAU 01393T (98.5%), Neorhizobium tomejilense T17_20T (98.4%), Neorhizobium huautlense S02T (98.4%), and Neorhizobium galegae ATCC 43677T (98.0%). Phylogenetic analysis based on 16S rRNA genes indicated that strain T786T was a new member of the genus Neorhizobium. The digital DNA-DNA hybridization and average nucleotide identity values between strain T786T and related strains were estimated as 20.2-20.6% and 76.6-80.0%, respectively. The genomic DNA G + C content based on the draft genome sequence was 60.2%. The major cellular fatty acids were Summed feature 8 (C18:1 ω7c or C18:1 ω6c), C16:0 and Summed feature 3 (C16:1 ω7c or C16:1 ω6c). The polar lipids were diphosphatidyl glycerol, phosphatidyl glycerol, phosphatidyl ethanolamine, phosphatidyl methyl ethanolamine, unidentified phospholipid and unidentified lipids (1-4). The isoprenoid quinone was ubiquinone-10. The DAP and sugar components of cell wall were meso-DAP and ribose, glucose, respectively. Based on phenotypic, phylogenetic, and genotypic data, for which the name Neorhizobium xiangyangii sp. nov. is proposed. The type strain is T786T (= JCM 35100T = CICC 25102T).

Kinetic and stability study on the immobilized enzymatic step of one‐pot dimerization of 2‐[2‐(dimethylamino)ethoxy]ethanol

Tertiary amine catalysts (TACs) are essential organic molecules used in polyurethane manufacturing. Synthesis of these chemicals involves the use of catalytic transition metals at high temperatures and high pressures. Simple amine systems react easily with transition metals; however, amine systems with multiple hydroxyl groups and methylamine complexes produce significant byproducts. In this study, synthesis that forgo transition metals is explored. Enzymes can provide a clean industrial alternative to transition metal use. 2‐[2‐(dimethylamino)ethoxy]ethanol (DMAEE) is the monomer used in the synthesis of a model TAC. When DMAEE is first enzymatically oxidized, the aldehyde can serve as an electrophile for 2‐(methylamino)ethanol (MMEA), forming the DMAEE dimer. Choline oxidase catalysis is the first step of this pathway. Steady state kinetic parameters of choline oxidase with choline and DMAEE as substrates, optimum pH, and temperature stability are reported in this study. The effect of MMEA on the enzymatic reaction is examined as well. In an industrial application, immobilized enzymes can enhance stability over a broad range of temperature and pH. Therefore, choline oxidase was immobilized on CNBr‐activated Sepharose beads, and the effects of immobilization are reported in this study.

Solubility of N2O and CO2 in nonaqueous blends of 2-(methylamino)ethanol and 2-methoxyethanol

Nonaqueous secondary alkanolamine-based systems, replacing conventional water with 2-alkoxyethanols as cosolvents, have recently attracted much attention for an energy-efficient CO2 capture process. In this work, physical solubility of N2O and CO2 in 2-(methylamino)ethanol (MAE), 2-methoxyethanol (2-ME) and their blends was measured and correlated at temperatures ranging from (283.2 to 333.2) K. Vapor-liquid equilibrium (VLE) data for the CO2 + MAE + 2-ME system at 7.8, 19.4 and 39.1 mass% MAE were also measured in a stirred equilibrium cell at temperatures of (313.2–393.2) K and CO2 partial pressures up to 270 kPa. VLE data were represented by a modified Kent-Eisenberg model with an AARD of 12.6%. The apparent equilibrium constants considering the liquid nonideality were well correlated as a function of temperature, concentration of carbamate product and CO2 loading.

Densities, Viscosities, and Excess/Deviation Properties of the Ternary System 2-(Methylamino)ethanol + Dimethyl Sulfoxide + Water and the Binary Subsystems

Densities and viscosities of the ternary system 2-(methylamino)ethanol (MAE) + DMSO + water and its corresponding binary constituents have been measured experimentally over the whole composition range and the temperature range from 293 to 353 K. The excess molar volumes (VE), viscosity deviations (Δη), and excess free energies of activation (ΔG*E) of the binary systems were correlated with the Redlich–Kister equation, while the experimental data of ternary mixtures were represented by using Nagata–Tamura, Cibulka, Singh, and Redlich–Kister equations. For binary mixtures, the VE values of aqueous DMSO and aqueous MAE are negative but positive for the nonaqueous blend of MAE + DMSO. The values of Δη and ΔG*E of aqueous binary systems are positive and negative, respectively, for the binary mixture of MAE + DMSO over the whole composition range and at all temperatures. These behaviors can be interpreted with molecular interactions and structural effects. The V123E and Δη123 values have also been derived from the experimental data of the ternary system. It was found that the V123E values are negative except for the regions highly deficient in water. The values of Δη123 become more positive in both H2O- and MAE-rich regions that were highly poor in DMSO. The observed behaviors indicate that the properties of the ternary system investigated are dominated by binary effects.

Densities and viscosities of partially carbonated nonaqueous blends of 2-(methylamino)ethanol with 2-alkoxyethanols at temperatures of (293.15 to 353.15) K

Nonaqueous blends of alkanolamines with 2-alkoxyethanols have recently attracted much attention for an energy-efficient CO2 capture process. In this work, densities and viscosities of partially CO2-loaded mixtures of 2- (methylamino)ethanol (MAE) with 2-methoxyethanol (EGME), 2-ethoxyethanol (EGEE) and 2-butoxyethanol (EGBE) were measured at atmospheric pressure over the temperature range of (293.15 to 353.15) K with amine mass fractions of (0.10, 0.30 0.40 and 0.50) containing various CO2 loading. It was observed that both densities and viscosities of the carbonated solutions showed noticeable changes as increasing CO2 loading, amine concentration and temperature. Dimensionless parameters from the CO2-free and CO2-loaded property data were fitted by proposed correlations. The calculated values of density and viscosity from the correlation models matched well with the experimental results of MAE + CO2 + 2-alkoxyethanols, with AARDs within 0.28% and 2.20% for density and viscosity respectively. These results are useful to evaluate the mass transfer and hydrodynamic performance in a CO2 capture process using these nonaqueous absorbents.

Straightforward Synthesis of Amido Polyols from Epoxidized Soybean Oil for Polyurethane Films

AbstractThis work reports a straightforward and selective method for the preparation of a polyol that can be used in the manufacture of polyurethane (PU) films. The polyol, from the N‐hydroxyalkylamides family, is obtained from the selective amidation and oxirane ring opening of epoxidized soybean oil (ESO) with the amino alcohol N‐methylethanolamine (N‐MEA). The reaction is carried out under mild conditions and in the absence of solvents and catalysts. Other similar amino alcohols (namely monoethanolamine (ETA), 5‐amino‐1‐pentanol (PEA), and 2‐(2‐aminoethoxy)ethanol (AEE)) are also used to carried out the amidation of ESO. However, for these amines, the amidation and/or oxirane ring opening of ESO is not complete. Therefore, the N‐hydroxyalkylamide obtained from the amidation of ESO with N‐MEA is chosen as the polyol for the preparation of PU films. The PU films are obtained from the reaction with a trimer of hexamethylene diisocyanate (Tolonate) and hexamethylene diisocyanate (HDI). Curing proceeds at room temperature, without catalyst. It is shown that the properties of the resulting PU films are dependent on the amount of Tolonate in the formulation.

Refractive Indices and Related Properties for Binary Mixtures of Methyl Acetate and Derivatives of Alkanolamines at Temperature Ranging from 293.15 to 313.15 K

Refractive indices, n D, of two binary liquid systems of methyl acetate (MAc) + methylethanolamine (MEA), and MAc + dimethylethanolamine (DMEA) each at twenty-one different compositions at T = 293.15, 303.15 and 313.15 K under ambient pressure are reported. The effect of temperature on the n D values is relatively small and the higher the temperature, the lower the refractive index. From the n D data, deviation in refractive indices, Δn D, molar refraction, R m, as well as deviation in molar refractions, ΔR m are estimated. The Δn D and ΔR m were correlated with the Redlich–Kister equation. For each system, as a function of composition of alkanolamines, x 2, the Δn D form a single positive lobe with a maximum between 0.5 and 0.65 mole fraction of alkanolamine. The ΔR m for both the systems are positive, the maxima lying within x 2 = 0.3 to 0.5.

Streptomyces liangshanensis sp. nov., a novel actinomycete isolated from rhizosphere soil of Fagopyrum tataricum.

A novel actinomycete strain, designated strain QMT-12T, was isolated from the rhizospheric soils of Fagopyrum tataricum and characterized using a polyphasic approach. Strain QMT-12T was found to have morphological features typical of the genus Streptomyces. The predominant fatty acids included C18:1 cis9 (35.9%), Summed feature 6 (C18:2 cis9, 12/C18:0 a or C18:0 anteiso/C18:2 c) (30.6%) and C16:0 (16.3%). The whole-cell sugars were arabinose and glucose. The whole-cell-wall amino acids included alanine, aspartate, glutamic acid, glycine and LL-diaminopimelic acid. The menaquinones were MK-9, MK-9(H2), MK-9(H4), MK-9(H6) and MK-9(H8). The diagnostic phospholipids consisted of diphosphatidyl glycerol, phosphatidylethanolamine, phosphatidyl methyl ethanolamine, phospholipids, phosphotidyl inositol, phosphotidylinositol mannosides, and phospholipids of unknown structure containing glucosamine. The full-length 16S rRNA gene sequence analysis showed that strain QMT-12T belonged to the genus Streptomyces and had 98.2, 98.1, 98.1 and ≤ 98.0% similarities to Streptomyces camponoticapitis 2H-TWYE14T, Streptomyces scopuliridis NRRL B-24574T, Streptomyces inhibens NEAU-D10T and other Streptomyces species with validly published and correct names, respectively. Phylogenetic analysis indicated that strain QMT-12T was closely relatedto Streptomyces inhibens NEAU-D10T. However, the average nucleotide identity value and the digital DNA-DNA hybridization value between strain QMT-12T and S. inhibens NEAU-D10T were 85.0 and 22.3%, respectively, well below 95-96% and 70% cut-off point recommended for delineating species. Based on its phenotypic and genotypic characteristics, strain QMT-12T (= CICC 11056T = JCM 33963T) represents the type strain of a novel species, for which the name Streptomyces liangshanensis sp. nov. is proposed.