Reclaiming of Amine CO2 Solvent Using Extraction of Heat Stable Salts in Liquid-Liquid Membrane Contactor.

Amine CO2 solvents undergo oxidative degradation with the formation of heat stable salts (HSS). These HSS reduce the sorption capacity of amines and lead to intense corrosion of the equipment. In our work, we propose a membrane-supported liquid-liquid extraction of the HSS from alkanolamines. For this purpose, a hollow fiber membrane contactor was used for the first time. A lab-scale extraction system on the basis of a hollow-fiber liquid-liquid membrane contactor with hollow fiber ultrafiltration polyvinylidenefluoride and polysulfone membranes has been studied. The extraction of the HSS-ions from a 30 wt.% solution of monoethanolamine was carried out using a 0.25-1 M solution of OH-modified methyltrioctylammonium chloride in 1-octanol as an extractant. It has been shown that >90% of HSS ions can be extracted from the alkanolamine solvent within 8 h after extraction. The results obtained confirm the possibility of using membrane extraction with a liquid-liquid membrane contactor for the reclaiming of amine CO2 solvents to increase the general efficiency of carbon dioxide capture.

Thermophysical Properties and Phase Behavior of Fluids for Application in Carbon Capture and Storage Processes.

Phase behavior and thermophysical properties of mixtures of carbon dioxide with various other substances are very important for the design and operation of carbon capture and storage (CCS) processes. The available empirical data are reviewed, together with some models for the calculation of these properties. The systems considered in detail are, first, mixtures of carbon dioxide, water, and salts; second, carbon dioxide-rich nonelectrolyte mixtures; and third, mixtures of carbon dioxide with water and amines. The empirical data and the plethora of available models permit the estimation of key fluid properties required in the design and operation of CCS processes. The engineering community would benefit from the further development, and delivery in convenient form, of a small number of these models sufficient to encompass the component slate and operating conditions of CCS processes.

An Experimental and Theoretical Study on the Unexpected Catalytic Activity of Triethanolamine for the Carboxylative Cyclization of Propargylic Amines with CO2.

Chemical conversion of CO2 under atmospheric pressure and metal-free conditions remains a great challenge. In this work, a series of alkanolamines, low-cost and biodegradable bases, were used to catalyze the carboxylative cyclization of propargylic amines with CO2 . Among these alkanolamines, triethanolamine (TEOA) was found to be a highly efficient organocatalyst for this important transformation at atmospheric pressure, and a series of desired products were synthesized in good to excellent yields. After the reactions, TEOA could be easily recovered and reused without obvious reduction in the efficiency. DFT studies revealed that TEOA may activate CO2 to form a ring-shaped carbonate intermediate that plays an important role in the catalysis of the reaction. This finding provides an effective and environmentally friendly alternative route for the production of 2-oxazolidinones.

Simultaneous analysis of mono-, di-, and tri-ethanolamine in cosmetic products using liquid chromatography coupled tandem mass spectrometry.

Alkanolamines such as monoethanolamine (MEA), diethanolamine (DEA), and triethanolamine (TEA) are used as wetting agents in shampoos, lotions, creams, and other cosmetics. DEA is widely used to provide lather in shampoos and maintain a favorable consistency in lotions and creams. Although DEA is not harmful, it may react with other ingredients in the cosmetic formula after extended storage periods to form an extremely potent carcinogen called nitrosodiethanolamine (NDEA), which is readily absorbed through the skin and has been linked to the development of stomach, esophagus, liver, and bladder cancers. The purpose of this study was to develop a simultaneous quantification method for measurement of MEA, DEA, and TEA in cosmetic products. Liquid chromatography coupled tandem mass spectrometry (LC-MS/MS) was performed using a hydrophilic interaction liquid chromatography (HILIC) column with isocratic elution containing acetonitrile and 5 mM ammonium formate in water (88:12, v/v). Identification and quantification of alkanolamines were performed using MS/MS monitoring to assess the transition from precursor to product ion of MEA (m/z, 61.1 â†’ 44.0), DEA (m/z, 106.1 â†’ 88.0), TEA (m/z, 150.1 â†’ 130.0), and the internal standard triethylamine (m/z, 102.2 â†’ 58.0). Alkanolamines extractions were simplified using a single extraction with acetonitrile in the cosmetic matrix. Performance of the method was evaluated with quality parameters such as specificity, carry-over, linearity and calibration, correlation of determination (R(2)), detection limit, precision, accuracy, and recovery. Calibration curves of MEA (2.9-1000 ppb), DEA (1-1000 ppb), and TEA (1-1000 ppb) were constructed by plotting concentration versus peak-area ratio (analyte/internal standard with a correlation coefficient greater than 0.99). The intra- and inter-assay accuracy ranged from 92.92 to 101.15 % for all analytes. The intra- and inter-assay precision for MEA, DEA, and TEA showed all coefficients of variance were less than 9.38 % for QC samples. Limits of detection and limits of quantification were 2.00 and 15.63 ppb for MEA, 0.49 and 1.96 ppb for DEA, and 0.49 and 1.96 ppb for TEA, respectively. This novel quantification method simplified sample preparation and allowed accurate and reproducible quantification of alkanolamines in the ng/g cosmetic weight (ppb) range for several cosmetic products.

Carbamate stabilities of sterically hindered amines from quantum chemical methods: relevance for CO2 capture.

The influence of electronic and steric effects on the stabilities of carbamates formed from the reaction of CO2 with a wide range of alkanolamines was investigated by quantum chemical methods. For the calculations, B3LYP, M11-L, MP2, and spin-component-scaled MP2 (SCS-MP2) methods were used, coupled with SMD and SM8 solvation models. A reduction in carbamate stability leads to an increased CO2 absorption capacity of the amine and a reduction of the energy required for solvent regeneration. Important factors for the reduction of the carbamate stability were an increase in steric hindrance around the nitrogen atom, charge on the N atom and intramolecular hydrogen bond strength. The present study indicates that secondary ethanolamines with sterically hindering groups near the N atom show significant potential as candidates for industrial CO2-capture solvents.

Ultrasound-assisted low-density solvent dispersive liquid-liquid extraction for the determination of alkanolamines and alkylamines in cosmetics with ion chromatography.

A new one-step sample preparation technique termed ultrasound-assisted low-density solvent dispersive liquid-liquid extraction (UA-LDS-DLLE) coupled with ion chromatography (IC) was developed for the determination of three alkanolamines and two alkylamines in complex samples. Sample matrices were rapidly dissolved and dispersed to form cloudy solutions by using two solvents, where target analytes were transferred into acid solutions, while liposoluble substances were dissolved in cyclohexane. The obtained extracts could be used directly for injection analysis without any additional purification because the potential matrix interferences had been effectively eliminated in extraction process. The extraction efficiency could be markedly enhanced and the extraction could be quickly accomplished within 13 min under the synergistic effects of ultrasound radiation, vibration and heating. Various parameters influencing extraction efficiency were evaluated using orthogonal array experimental design. The extraction performance of the approach was demonstrated for the determination of target analytes in 15 commercial cosmetics covering very different matrices. Linearity ranges of 0.3-50 mg L(-1) and limits of detection varying from 0.072 to 0.12 mg L(-1) were achieved. The recoveries ranged from 86.9-108.5% with the relative standard deviations (RSDs) of 1.2-6.2%. The method was proved to be a simple and effective extraction technique that provided an attractive alternative to the analysis of trace amounts of target analytes in large numbers of cosmetics.

Partial molar vllume of some alkanolamines in water at 298.15 k / Volumen molar parcial de algunas alcanolaminas en agua a 298,15 k / Volume molar paccial de algumas alcanolaminas em água a 298,15 k

Densities of aqueous solutions of 3-amino-1-propanol, 2-amino-1-propanol, 3-amino-1,2-propanediol, and 1,3-diamino-2-propanol were measured at 298.15 K using the vibrating tube technique. The apparent molar volumes of the alkanolamines were determined as a function of composition from experimental data and the solute limiting partial molar volume was obtained through extrapolation. The results are discussed in terms of the effect of the number and the position of polar groups in the molecules.

Las densidades de soluciones acuosas de 3-amino-1-propanol, 2-amino-1-propanol, 3-amino-1,2-propanodiol y 1,3-diamino-2-propanol fueron medidas a 298,15 K usando la técnica del tubo vibrante. Los volúmenes molares aparentes se determinaron en función de la composición a partir de los datos experimentales y los volúmenes molares parciales de los solutos a dilución infinita fueron obtenidos por extrapolación. Los resultados son discutidos en términos del efecto del número y la posición de los grupos polares en las moléculas.

As densidades de soluções aquosas de 3-amino-1-propanol, 2-amino-1-propanol, 3-amino-1,2-propanediol and 1,3-diamino-2-propanol foram medidas a 298 K utilizando a técnica de tubo vibratório. Os volumes molares aparentes das alcanolaminas foram determinados como uma função de composição partindo de dados experimentais e parciais volumes molares de solutos na diluição infinita foram obtidos por extrapolação. Os resultados são discutidos em termos do efeito do número e da posição dos grupos polares nas moléculas.