铁离子水解对白兰地酯酸平衡的影响

研究了白兰地酒中铁离子水解对酯酸平衡的影响。试验结果表明 ,在Fe含量微量超标、酸度偏低的情况下 ,适当提高白兰地的酸度 ,可抑制Fe3 +水解对酯酸平衡的破坏 ,防止沉淀生成 ,增强白兰地的稳定性。

低度白酒酸、酯平衡谈

从化学工程角度阐述低度白酒酸、酯平衡 ,引伸出适量增加酸值是稳定低度白酒质量的有力措施之一。

浅谈新型白酒中酸含量对酒质的影响

酸是新型白酒呈味的重要成分 ,是主要协调成分 ,是新酒老熟的催化剂。

脂肪酶应用于白酒催陈的初探

白酒催陈过程中最重要且耗时最长的环节是酸酯醇的平衡,利用脂肪酶只改变反应的动力学平衡而不能改变热力学平衡及催化作用特点,拟筛选合适的脂肪酶应用于白酒老熟中,以缩短老熟时间,并对其可行性进行探讨。通过在白酒中添加不同种类的脂肪酶,发现添加Novozym435的酒中,总酯变化幅度较为明显,且作用5h后,酶活保持50%左右。初步证明了脂肪酶应用于白酒催陈中的可能性,提出了一种新的白酒催陈思路。

引起白酒口干、上头问题的初探

引起白酒口干、上头的主要原因有酒中乙醛、杂醇油含量过高 ,酸酯比例不谐调 ,卫生指标、外加香料及酒精质量不过关等因素。解决措施有 :①白酒勾兑成型后适当延长贮存期 ;②降低白酒中杂醇油的含量 ;③适当延长作调味酒的酒头贮存期 ;④保证正常的发酵工艺过程 ;⑤生产过程严格卫生管理 ;⑥尽量选用发酵生产的香精香料。(孙悟)

Vapor-Liquid Equilibrium Data of Carbon Dioxide＋Methyl Propionate and Carbon Dioxide＋Propyl Propionate Systems

High-pressure vapor-liquid equilibrium data for the binary systems of methyl propionate＋carbon dioxide and propyl propionate＋carbon dioxide were measured at pressure from 1.00 MPa to 12.00 MPa and temperature in the range from 313 K to 373 K. Experimental results were correlated with the Peng-Robinson equation of state with the two-parameter van der Waals mixing rule. At the same time, the Henry＇s coefficient, partial molar enthalpy change and partial molar entropy change of CO2 during dissolution at different temperature were also calculated.

白酒入口甜、回味苦的产生原因及解决办法

新型白酒在经勾调后出现回苦,针对全国白酒行业普遍存在的这一技术难题,本文通过对白酒骨架成分理论,尤其是白酒中酸的成分进行分析,介绍了苦味物质产生的机理,提出了解决问题的可行性方案和建议:关键在于掌握白酒中各种酸量比的合理区间,使酸酯达平衡。

Measurement and Correlation of Solid-Liquid Equilibria of Phenyl Salicylate with C4 Alcohols

In an equilibrium vessel,the solid-liquid equilibria(SLE) for three binary mixtures of phenyl salicylate with 1-butanol,2-butanol,and 2-methyl-1-propanol,respectively,have been measured from 283.15 K to the melting temperature of the solute using a method in which an excess amount of solute was equilibrated with the alcohol solution.The liquid concentrations of the investigated phenyl salicylate in the saturated solution were analyzed by UV spectrometry.Activity coefficients for phenyl salicylate have been calculated by means of the Wilson,NRTL,and UNIQUAC equations and with them were correlated solubility data that were compared with the experimental ones.The best correlation of the solubility data has been obtained by the Wilson equation by which the average root-mean-square deviation of temperature for the three systems is 1.03 K.

Measurement and modelization of VLE of binary mixtures of propyl acetate,butyl acetate or isobutyl acetate with methanol at pressure of 0.6 MPa

The vapor-liquid equilibrium of binary mixtures of propyl acetate, butyl acetate and isobutyl acetate with meth- anol has been determined at a constant pressure of 0.6 MPa. Results have been modeled with the Peng-Robinson equation, a traditional cubic equation of state widely employed in chemical industries, as well as with the perturbed-chain statistical associating fluid PC-SAFT theory of Gross-Sadowski. By correlation of the binary inter- action parameters of these equations, the measured vapor-liquid equilibrium data can be accurately predicted. Thus, this work shows that these models are able to represent the experimental data for systems with associating comoounds via hydrogen bonding.

Experimental Measurements and Correlations Isobaric Vapor-Liquid Equilibria for Water ＋ Acetic Acid ＋ Sec-butyl Acetate at 101.3 kPa

Isobaric vapor-liquid equilibrium(VLE) data for acetic acid + sec-butyl acetate and water+acetic acid + sec-butyl acetate systems were determined at 101.3 kPa using a modified Rose type.The nonideality of the vapor phase caused by the association of the acetic acid was corrected by the chemical theory and Hayden-O'Connell method.Thermodynamic consistency was tested for the binary VLE data.The experimental data were correlated successfully with the Non-Random Two Liquids(NRTL) model.The Root Mean Square Deviation(RMSD) of the ternary system was 0.0038.The saturation vapor pressure of sec-butyl acetate at 329 to 385 K was measured by means of two connected equilibrium cells.The vapor pressures of water and sec-butyl acetate were correlated with the Antoine equation.The binary interaction parameters and the ternary VLE data were obtained from this work.

Reactive Distillation for Producing n-Butyl Acetate:Experiment and Simulation

In this paper, a reactive distillation (RD) column was applied for synthesis n-butyl acetate from n-butanol and acetic acid. The Langmuir-Hinshelwood-Hougen-Watson (LHHW) kinetic model and an equilibrium stage model for separation were employed to study the RD process. The results obtained from the equilibrium stage model agreed well with the experiments. The effects of operating variables on the n-butanol conversion and n-butyl acetate purity were further investigated. The optimal column configuration for the production of n-butyl acetate was designed with 5 rectifying stages, 8 reaction stages and 13 stripping stages by the simulation study. According to the simulation results, n-butanol conversion and n-butyl acetate purity all reached greater than 96%.

Synthesis of Toluene-2,4-Bisurea from 2,4-Toluene Diamine and Urea and the Reaction Kinetics

Toluene-2,4-bisurea (TBU) is an important intermediate for urea route to dimethyl toluene-2,4-dicarbamate and the study on TBU synthesis via the reaction of 2,4-toluene diamine (TDA) and urea is of great significance. Firstly, thermodynamic analysis shows that the reaction is exothermic and a high equilibrium conversion of TDA is expected due to its large reaction equilibrium constant. Secondly, under the suitable reaction conditions, 130 °C, 7 h, and molar ratio of TDA/zinc acetate/urea/sulfolane 1/0.05/3.5/10, TDA conversion is 54.3%, and TBU yield and selectivity are 39.8% and 73.3% respectively. Lastly, the synthesis of TBU is a 1st order reaction with respect to TDA and the reaction kinetics model is established. This work will provide useful information for commercializing the urea route to toluene-2,4-dicarbamate (TDC).

Study on Hydrolysis of Methyl Acetate in a Catalytic Distillation Column

A nonequilibrium stage model was used to simulate countercurrent multicomponent catalytic distillation processes for methyl acetate hydrolysis. Computations of stage efficiencies or height equivalent to a theoretical plate (HETP) were entirely avoided by this model. The consistency of simulated results and experimental data in conversions and concentration of each component along a column indicates that the model predicts the actual process well. The influences of operating parameters on hydrolytic conversions, such as feed molar ratios, feed locations, feed and reflux rates, heights of reactive and stripping sections, were analyzed adequately by simulating calculations. A good operating mode was then obtained, which is helpful to the development of a new process.

Solid-Liquid Equilibria of trans-1,2-Cyclohexanediol＋Butyl Acetate＋ Water Ternary System

Using a laser observation technique,the solubilities of trans-1,2-cyclohexanediol in butyl acetate+wa- ter were measured at the temperature range from 298.15K to 323.15K by a synthetic method at atmospheric pres- sure.It is shown that the solubilities of trans-1,2-cyclohexanediol in butyl acetate+water were affected greatly by the proportion of butyl acetate and water,and presented maximum value at given temperature.The UNIFAC model was used to correlate the experimental data.The average relative deviation(ARD)between experimental and calculated values is 3.03%.

浅谈白酒之勾储

色谱骨架成分含量的不同比例,是白酒香型风格的"构成要素";白酒质量档次的提高,取决于微量的复杂成分含量;酸酯平衡是酒体协调的基本因素;白酒的储存,是提高酒质醇和度的基本措施。

Vapour-Liquid Equilibrium with a New Ebulliometer：Ester＋Alcohol System at 0.5 MPa

A new dynamic ebulliometer is used to determine vapor-liquid equilibrium(VLE) data experimentally. In the equipment,both phases are recirculated. Its operation is a consequence of the Cotrell pump effect produced when the mixture is heated in a double-walled inverted vessel. The reliability of the apparatus is tested with the mixtures studied previously by various authors. VLE data for the binary systems of methyl acetate + methanol and the methyl acetate + ethanol at 0.5 MPa are determined. The experimental data are confirmed with the point-to-point test of van Ness,applying the Fortran program of Frendslund et al. In addition,the experimental results are com-pared with the UNIFAC(including different versions) and ASOG prediction models.

Isobaric Vapor-Liquid Equilibrium of Binary Systems： p-Xylene ＋ （Acetic Acid, Methyl Acetate and n-Propyl Acetate） and Methyl Acetate ＋ n-Propyl Acetate in an Acetic Acid Dehydration Process

The vapor-liquid equilibrium data of four binary systems (acetic acid +p-xylene, methyl acetate +n-propyl acetate, n-propyl acetate +p-xylene and methyl acetate +p-xylene) are measured at 101.33 kPa with Ellis equilibrium still, and then both the NRTL and UNIQUAC models are used in combination with the HOC model for correlating and estimating the vapor-liquid equilibrium of these four binary systems. The estimated binary VLE results using correlated parameters agree well with the measured data except the methyl acetate +p-xylene system which easily causes bumping and liquid rushing out of the sampling tap due to their dramatically different boiling points. The correlation results by NRTL and UNIQUAC models have little difference on the average absolute deviations of temperature and composition of vapor phase, and the results by NRTL model are slightly better than those by UNIQUAC model except for the methyl acetate +n-propyl acetate system, for which the latter gives more accurate correlations.

Liquid-Liquid Equilibria of the Water-Ethanol-Dimethyl Succinate Ternary System

Liquid-liquid equilibrium (LLE) data for the ternary systemwater-ethanol-dimethyl succinate have been determined experimentallyat temperatures ranging from 298.15 to 318.15 K at 5 K intervals.Complete phase diagrams were obtained by determining solubility andthe tie-line data. Tie-line compositions were correlated byOthmer-Tobias method. The universal quasichemical functional groupactivity coefficient (UNIFAC) and modified UNIFAC methods were usedto predict the phase equilibrium in the system using the interactionparameters deter- Mined from experimental data between groups CH_3,CH_2, OH, CH_3 COO and H_2O.

Distribution Equilibrium of o-Phthalic Acid and trans-Butenedioic in Water and Di-n-butyl Phthalate

The organic dissolvent （di-n-butyl phthalate） needs to be washed by water to recycle itself in the process of recovering maleic anhydride by organic dissolvent. The design and optimization of the extraction process require the distribution coefficients of the organic solutes, o-phthalic acid and trans-butenedioic in water and di-n-butyl phthalate, on which the extraction efficiency depends. In this study, the distribution coefficients of o-phthalic acid and trans-butenedioic in water and all-n-butyl phthalate（DBP） at 298.15 K, 318.15 K and 333.15 K were determined respectively by acid-alkali titration. The dissociation constants of o-phthalic acid and trans-butenedioic at those temperatures were obtained by fitting the measured hydrogen-ion concentrations and the known solute concentrations in the aqueous solution containing the two organic solutes. Then the distribution constants were calculated. Both the distribution coefficients and the distribution constants increase along with the temperature increasing. And the distribution coefficients at 333. 15 K are large enough to ensure the efficiency of extraction process. In addition, the mutual solubility of water and all-n-butyl phthalate at 298.1.5 K, 318. 1.5 K and 333. 15 K was also measured respectively by High Performance Liquid Chromatography and Karl Fischer Watertitration, which was not more than 0. 5%（ mass fraction ）.

Experimental Study on Liquid-Liquid Equilibria of Alcohol- Ester-Water-CaCl_2 System

The binary liquid-liquid equilibrium(LLE) data for salt-containing systems of 1-butanol+water+CaCl2, n-butyl acetate+water+CaCl2 and ethyl acetate+acetic acid+water+CaCl2 were determined and the salt effect was analyzed. The results showed that an obvious salt effect could be identified for the systems of 1-butanol+water+CaCl2 and ethyl acetate+acetic acid+water.