Ab initio Study on Ionization Energies of 3-Amino-1-propanol

Fourteen conformers of 3-amino-1-propanol as the minima on the potential energy surface are examined at the MP2/6-311＋＋G＊＊ level. Their relative energies calculated at B3LYP, MP3 and MP4 levels of theory indicated that two most stable conformers display the intramolecular OH - N hydrogen bonds. The vertical ionization energies of these conformers calculated with ab initio electron propagator theory in the P3/aug-cc-pVTZ approximation are in agreement with experimental data from photoelectron spectroscopy. Natural bond orbital analyses were used to explain the differences of IEs of the highest occupied molecular ortibal of conformers. Combined with statistical mechanics principles, conformational distributions at various temperatures are obtained and the temperature dependence of photoelectron spectra is interpreted.

Regeneration of 2-amino-2-methyl-1-propanol used for carbon dioxide absorption

To improve the efficiency of the carbon dioxide cycling process and to reduce the regeneration energy consumption, a sterically hindered amine of 2-amino-2-methyl-1- propranol （AMP） was investigated to determine its regeneration behavior as a CO2 absorbent. The CO2 absorption and amine regeneration characteristics were experimentally examined under various operating conditions. The regeneration efficiency increased from 86.2% to 98.3% during the temperature range of 358 to 403 K. The most suitable regeneration temperature for AMP was 383 K, in this experiment condition, and the regeneration efficiency of absorption/regeneration runs descended from 98.3% to 94.0%. A number of heat-stable salts （HSS） could cause a reduction in CO2 absorption capacity and regeneration efficiency. The results indicated that aqueous AMP was easier to regenerate with less loss of absorption capacity than other amines, such as, monoethanolamine （MEA）, diethanolamine （DEA）, diethylenetriamine （DETA）, and N-methyldiethanolamine （MDEA）.

Highly efficient synthesis of 1-methoxy-2-propanol using ionic liquid catalysts in a micro-tubular circulating reactor

The catalysis of ionic liquids (ILs) in the traditional stirred reactor suffers from insufficient mass and heat transfer, which always needs a long reaction time and results in a low reaction rate. In this work, highly efficient synthesis of 1-methoxy-2-propanol via the alcoholysis reaction of propylene oxide (PO) with methanol was proposed and achieved by the combination of micro-tubular circulating reactor with the IL [N4444] [Buty] catalyst. Compared with the stirred reactor, the rate of alcoholysis reaction in a micro-tubular circulating reactor was found to be significantly improved. The reaction time was remarkably shortened to 20 min from 180 min as well as the yield of 1-methoxy-2-propanol reached 92%. Moreover, the kinetic study further demonstrated that the main reaction rate to 1-methoxy-2-propanol (K1) was about 20 times larger than the side reaction rate to byproduct 2-methoxy-1-propanol (K2) in the temperature range of 363–383 K. Such combination of micro-tubular circulating reactor with IL catalysts is believed to be a class of effective process intensification technique for highly efficient synthesis of 1-methoxy-2-propanol.

Investigation of liquid–liquid equilibrium of the ternary system(water +1,6-diaminohexane + 2-methyl-1-propanol or 3-methyl-1-butanol) at different temperatures

In this study, the LLE data of ternary system(water + 1,6-diaminohexane + 2-methyl-1-propanol) and(water +1,6-diaminohexane + 3-methyl-1-butanol) were measured at 293.15, 303.15 and 313.15 K under atmospheric pressure. Reliability of the experimental tie-line data was checked by empirical Hand, Othmer-Tobias and Bachman equations. Distribution coefficient(D) and selectivity(S) were calculated in order to investigate capability of the studied organic solvents for 1,6-diaminohexane extraction. The high values of separation factors demonstrated that 2-methyl-1-propanol and 3-methyl-1-butanol were applicable for this purpose. The experimental data were correlated by nonrandom two-liquid(NRTL) and universal quasi-chemical(UNIQUAC) models.The percent-root-mean-square deviation(RMSD) values for NRTL and UNIQUAC models were less than 0.15,which indicated that the experimental data have been sufficiently correlated.

Salt-Containing Extractive Distillation of 1-Propanol/Water System 1.Prediction of Salt Effect on Vapor Liquid Equilibrium

This paper has studied the vapor-liquid equilibrium （VLE） for the salt-containing extractive distillation of the 1-propanol/water system. Binary VLE data were measured for the systems of 1-propanol （1）/KAc （4）, ethanediol （3）/KAc （4）, and 1-propanol （1）/ethanediol （3）, with the VLE data correlated with the NRTL model in order to obtain the model parameters of these binary systems. The binary VLE data cited in technical literature were correlated to obtain the model parameters for other binary systems. VLE data of ternary and quaternary systems predicted by the NRTI.： model agreed well with the literature data. The influence of KAc, ethanediol, and the KAc/ethanediol mixture on volatility between 1-propanol and water was investigated respectively. Test results showed that the above-mentioned materials （KAc, ethanediol） and their mixture （KAc and ethanediol） have different influence on the volatility. When x3=0.5, and x4=0.05, the azeotropic point can be elimi- nated. The NRTL model method of salt-containing VLE is simple and effective for the prediction of the system＇s VLE data.

A Computational Study on the Mechanism for the K_2CO_3-catalyzed Reaction of Carbon Dioxide and 1-Chlo-2-propanol

The microcosmic reaction mechanism of K2CO3-catalyzed 1-chlo-2-propanol and carbon dioxide has been investigated by density functional theory（DFT） at the GGA/PW91/DNP level.We optimize the geometric configurations of reactants,intermediates,transition states,and products.The energy analysis calculation approves the authenticity of intermediates and transition states.According to our calculations,four feasible reaction pathways are found.The main pathway of the reaction is ReA → IMA1 → TSA1 → IMA2 → IMA5 → TSA5 → P.Besides,we also in-vestigate the reaction mechanism of 1-chlo-2-propanol and carbon dioxide without K2CO3-catalyzation by the same theory and level.The computational results indicate that the activation barrier with K2CO3-catalyzed is smaller than the activation barrier without K2CO3-catalyzed.That is to say,K2CO3 can promote the reaction to give the product in a high yield,which is in agreement with the experimental results.

CHROMATOGRAPHIC SEPARATION OF THE ENANTIOMERS OF 3-PHENYL-1,2-EPOXYETHANE AND 1-PHENYL-1-PROPANOL ON A FUSED SILICA CAPILLARY COLUMN COATED WITH PERBENZYL-β-CYCLODEXTRIN

A β-cyclodextrin derivative, perbenzyl-β-cyclodextrin, was prepared and used as a chiral stationary phase for capillary gas chromatography. Using FID detector and the column temperature between 70 and 80℃, the chiral separations of racemic 3-phenyl-1, 2-epoxyethane and 1-phenyl-1-propanol on a 14m×0.23mm I. D. fused silica column with the β-cyclodextrin derivative were carried out and the optical purities of optically active 1-phenyl-1-propanol samples prepared by asymmetric synthesis were determined.

沉淀聚合法制备1-苯丙醇印迹聚合物微球的研究

以1-苯丙醇为印迹分子,甲基丙烯酸为功能单体,利用沉淀聚合法制备了分子印迹聚合物微球.考察了聚合反应条件,如溶剂种类、聚合温度、模板浓度、引发剂用量、转速、预聚合时间等对分子印迹聚合物微球特性的影响.静态吸附实验结果表明,在模板浓度为0.01 mol/L、引发剂浓度0.01 mol/L条件下,在乙腈溶液中60℃沉淀聚合可制备出吸附量大且有特异性识别能力的分子印迹聚合物微球.

Kinetics and Mechanism of Oxidation of 1-Methoxy-2-propanol and 1-Ethoxy-2-propanol by Ditelluratocuprate（lll） in Alkaline Medium

The kinetics of oxidation of 1-methoxy-2-propanol and l-ethoxy-2-propanol by ditelluratocuprate（III） （DTC） in alkaline liquids has been studied spectrophotometrically in the temperature range of 293.2-313.2 K. The reaction rate showed first order dependence in DTC and fractional order with respect to l-methoxy-2-propanol or 1-ethoxy-2-propanol. It was found that the pseudo-first order rate constant kobs increased with an increase in concentration of OH- and a decrease in concentration of TeO4^2- . There is a negative salt effect. A plausible mechanism involving a pre-equilibrium of a adduct formation between the complex and 1-methoxy-2-propanol or 1-ethoxy-2-propanol was proposed. The rate equations derived from mechanism can explain all experimental observations. The activation parameters along with the rate constants of the rate-determining step were calculated.

Effects of alcohol additives on pore structure and morphology of freeze-cast ceramics

The porous alumina ceramics with lamellar structure were fabricated successfully by freeze casting. The viscosities of alumina slurries, pore structures, porosities and mechanical properties of the sintered ceramics were investigated by introducing both types of alcohols as water solidification modifier into the initial slurries, such as ethanol and 1-propanol. With the addition of ethanol or 1-propanol, the viscosities of slurries increased and porosities of sintered ceramics decreased. The compressive strengths of the sintered porous alumina ceramics were improved due to a good connectivity between lamellae with the addition of both types of alcohols. The lowest porosities of 68.52% and 73.72% and highest compressive strengths of 18.2 MPa and 15.0 MPa were obtained by the addition of 30% ethanol in mass fraction and 1-propanol, respectively.

Removal characteristics of CO_2 using aqueous MEA/AMP solutions in the absorption and regeneration process

The carbon dioxide （CO2） removal efficiency, reaction rate, and CO2 loading into aqueous blended monoethanolamine （MEA） ＋ 2-amino-2-methyl-l-propanol （AMP） solutions to enhance absorption characteristics of MEA and AMP were carried out by the absorption/regeneration process. As a result, compared to aqueous MEA and AMP solutions, aqueous blended MEA ＋ AMP solutions have a higher CO2 loading than MEA and a higher reaction rate than AMP. The CO2 loading of rich amine of aqueous 18 wt.% MEA ＋ 12 wt.% AMP solution was 0.62 mol CO2/mol amine, which is 51.2% more than 30 wt.% MEA （0.41 mol CO2/mol amine）. Consequently, blending MEA and AMP could be an effective way to design considering economical efficiency and used to operate absorber for a long time.

Absorption characteristics of new solvent based on a blend of AMP and 1,8-diamino-p-menthane for CO_2 absorption

Aqueous 1,8-diamino-p-menthane （KIER-C3） and commercially available amine solutions were tested for CO2 absorption. A 2-amino-2-methyl-1-propanol （AMP） solution with an addition of KIER-C3 showed 9.3% and 31.6% higher absorption rate for CO2 than the AMP solution with an addition of monoethanolamine （MEA） and ammonia （NH3）, respectively. The reaction rate constant for CO2 absorption by the AMP/KIER-C3 solution was determined by the following equation： k2,AMP/C3 = 7.702×106 exp （-2248.03/T）. A CO2 loading ratio of the AMP/KIER-C3 solution was also 2 and 3.4-times higher than that of the AMP/NH3 solution and the AMP/MEA solution, respectively. Based on the experimental results, KIER-C3 may be used as an excellent additive to increase CO2 absorption capability of AMP.

Electrochemical analysis and convection-enhanced mass transfer synergistic effect of MnO_x/Ti membrane electrode for alcohol oxidation

The different electrocatalytic reactors could be constructed for the electrocatalytic oxidation of 2,2,3,3-tetrafluoro-1-propanol(TFP) with two typical MnO_x/Ti electrodes, i.e.the electrocatalytic membrane reactor(ECMR) with the Ti membrane electrode and the electrocatalytic reactor(ECR) with the traditional Ti plate electrode.For the electro-oxidation of TFP, the conversion with membrane electrode(70.1%) in the ECMR was 3.3 and 1.7 times higher than that of the membrane electrode without permeate flow(40.8%) in the ECMR and the plate electrode(21.5%) in the ECR, respectively.Obviously, the pore structure of membrane and convection-enhanced mass transfer in the ECMR dramatically improved the catalytic activity towards the electro-oxidation of TFP.The specific surface area of porous electrode was 2.22 m^2·g^(-1).The surface area of plate electrode was 2.26 cm^2(1.13 cm^2× 2).In addition, the electrochemical results showed that the mass diffusion coefficient of the MnO_x/Ti membrane electrode(1.80 × 10^(-6) cm^2·s^(-1)) could be increased to 6.87 × 10^(-6) cm^2·s^(-1) at the certain flow rate with pump, confirming the lower resistance of mass transfer due to the convection-enhanced mass transfer during the operation of the ECMR.Hence, the porous structure and convection-enhanced mass transfer would improve the electrochemical property of the membrane electrode and the catalytic performance of the ECMR,which could give guideline for the design and application of the porous electrode and electrochemical reactor.