Preparation of 1-butyl-3-methylimidazolium dodecatungstophosphate and its catalytic performance for esterification of ethanol and acetic acid

1-Butyl-3-methylimidazolium dodecatungstophosphate catalyst ([bmim]₃PW₁₂O₄₀) with high water tolerance was prepared from 1-butyl-3-methylimidazolium bromide ([bmim]Br) and phosphotungstic acid (H₃PW₁₂O₄₀). The catalyst was characterized by means of Fourier transform infrared spectroscopy, thermogravimetry-differential scanning calorimetry, n-BuNH₂ potentiometric titration, elemental analysis and so on. Its catalytic activity for esterification of ethanol and acetic acid to ethyl acetate was measured. The results show that there were three crystal-water molecules in the [bmim]₃PW₁₂O₄₀ catalyst, and it preserved the primary Keggin structure and acid strength of H₃PW₁₂O₄₀. The acid amount of [bmim]₃PW₁₂O₄₀ catalyst was less than that of H₃PW₁₂O₄₀. The [bmim]₃PW₁₂O₄₀ catalyst exhibited higher catalytic activity and reusability in the esterification of ethanol and acetic acid to ethyl acetate. __________ Translated from Chinese Journal of Catalysis, 2008, 29(7) (in Chinese)     

Hydrogenation of ethyl acetate over supported rhenium catalysts

Re/Sibunite is a more active and selective catalyst for hydrogenation of ethyl acetate to ethanol under elevated temperatures and hydrogen pressures than Re/θ-Al₂O₃ and Re/γ-Al₂O₃. The activity of the catalyst is increased on replacing NH₄ReO₄ with HReO₄ and treatment of the support with a 13% solution of HNO₃. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1006–1008, May, 1999.     

Kinetics of esterification of acetic acid with n-butanol over different homogeneous acid catalysts

The esterification reaction of n-butanol and acetic acid has been performed in batch reactor in the presence of different homogeneous acid catalyst, namely sulfuric acid, nitric acid, and para toluene sulfonic acid (p-TSA). The objective of present research work is to investigate kinetic behavior of esterification reaction over the temperature range of 60°C–80°C. The effect of reaction parameter such as catalyst loading varied from 1% to 5% v/v and acid to alcohol molar ratio of 1:1, 1:3, and 1:5 has been observed. A pseudo homogeneous kinetic model has been applied. Kinetic parameters such as equilibrium constant, reaction rate constant, enthalpy, activation energy, and entropy were calculated by the experimental data for different acid catalyst system. It was observed that sulfuric acid gives higher conversion 73% than p-TSA 68.5% and nitric acid 66.25% at temperature of 80°C, 1:1 molar ratio and 3% catalyst concentration. The activation energy was estimated 36448.49, 23324.31 and 19060.156 J/mol K for three different catalyst sulfuric acid, nitric acid and p-TSA respectively. The enthalpy and entropy of the esterification reaction of acetic acid with n-butanol over three different catalysts has been calculated (Enthalpy: 25.788 KJ/mol, 12.256 KJ/mol, 28.320 KJ/mol, Entropy: 88.1 J/mol K, 45.298 J/mol K, 91.44 J/mol K) and found enthalpy is having positive value that shows reaction is endothermic.     

磷化过程对MoP催化剂醋酸加氢合成乙醇性能的影响

制备了系列磷化钼催化剂用于醋酸加氢合成乙醇活性评价,并采用XRD、XPS和SEM等技术对催化剂进行表征。结果表明,催化剂除含有MoP外,还有MoP_2O_7和MoO_2等物种,催化醋酸生成乙醇的活性物种是MoP,或者是MoP与MoP_2O_7、MoO_2协同起催化作用。磷化温度一定程度上影响催化剂的形成和活性组分的分布,磷化温度太低,MoP形成量少,磷化温度太高,MoP发生团聚和烧结,磷化温度为650℃时制备的催化剂活性最高。磷钼物质的量比为1.0时催化剂的乙醇合成性能最高。     

Phase behaviour of ethanol + water + ethyl acetate at 101.3 kPa

Must distillation processes simulation is a challenging task, due to the lack of thermodynamic interaction parameters and accurate studies of phase equilibria. The presence of polar substances, those different from ethanol and water, and their low concentrations make it very difficult to model industrial distillation. Several of the congeners are essential enological components of the organoleptic matrix. In this work, we are concerned with the study of phase behaviour of ethanol + water + ethyl acetate at 101.3 kPa, this being the third compound, the legal congener of the highest composition in common alcoholic distillation. The experimental results showed partial miscibility and four azeotropes into a complex medium. Group contribution models yield poor results. Disposable literature was compared and commented upon. The lack of experimental data in multicomponent alcoholic distillation mixtures and the low reliability of the group contribution methods suggest a prudent application to process simulation.     

Effect of ethyl acetate on carbohydrate components and crystalline structure of pulp produced in aqueous acetic acid pulping

The aim of this study was to investigate the changes in carbohydrate components and the crystalline structure in hemp bast fibers by adding ethyl acetate to acetic acid/water pulping processes. It was found that ethyl acetate added to acetic acid/water process had a positive effect on yield, viscosity and carbohydrate components in pulp. It was assumed that the delignification ratio increased by adding ethyl acetate to aqueous acetic acid pulping. Xylose content in hemp bast fibers was affected more negatively in the ethyl acetate/acetic acid/water process than in the acetic acid/water one. Crystallinity and crystallite size were higher in pulp sample obtained by the acetic acid/water process without ethyl acetate.     

Acidity function of methanesulfonic acid solutions in ethyl acetate

The acidity function of solutions of methanesulfonic acid (MSA) in ethyl acetate (EA) was measured by the indicator method at 25 °C in the 0.4—100% concentration range. Molecular complexes formed by MSA and EA show a higher ionizing activity than H₅O₂ ⁺ ions. The relative ionizing activity of the MSA·EA complexes and ion pairs formed by MSA and DMF was determined.     

Esterification of levulinic acid to n-butyl levulinate over heteropolyacid supported on acid-treated clay

Levulinic acid has been identified as a promising green, biomass-derived platform chemical. n-Butyl levulinate is used as an important intermediate having diverse applications. The present work focuses on the synthesis of n-butyl levulinate by esterification of levulinic acid with n-butanol using heteropolyacid (HPA) supported on acid-treated clay montmorillonite (K10). 20% (w/w) dodecatungestophosphoric acid (DTPA) supported on K10 was found to be the most efficient catalyst with 97% levulinic acid conversion and 100% selectivity towards n-butyl levulinate. Effects of various process parameters were studied to examine the efficacy of 20% (w/w) DTPA/K10 for optimization of the activity.     

Selective catalytic oxidation of ethanol to acetic acid on dispersed Mo-V-Nb mixed oxides

The direct oxidation of ethanol to acetic acid is catalyzed by multicomponent metal oxides (Mo-V-NbO(x)) prepared by precipitation in the presence of colloidal TiO(2) (Mo(0.61)V(0.31)Nb(0.08)O(x)/TiO(2)). Acetic acid synthesis rates and selectivities (~95 % even at 100 % ethanol conversion) were much higher than in previous reports. The presence of TiO(2) during synthesis led to more highly active surface areas without detectable changes in the reactivity or selectivity of exposed active oxide surfaces. Ethanol oxidation proceeds via acetaldehyde intermediates that are converted to acetic acid. Water increases acetic acid selectivity by inhibiting acetaldehyde synthesis more strongly than its oxidation to acetic acid, thus minimizing prevalent acetaldehyde concentrations and its intervening conversion to CO(x). Kinetic and isotopic effects indicate that C-H bond activation in chemisorbed ethoxide species limits acetaldehyde synthesis rates and overall rates of ethanol conversion to acetic acid. The VO(x) component in Mo-V-Nb is responsible for the high reactivity of these materials. Mo and Nb oxide components increase the accessibility and reducibility of VO(x) domains, while concurrently decreasing the number of unselective V-O-Ti linkages in VO(x) domains dispersed on TiO(2).     

Synthesis of some aromatic aldehydes and acids by sodium ferrate in presence of copper nano‐particles adsorbed on K 10 montmorillonite using microwave irradiation

Excellent yields were obtained in the oxidation of benzyl alcohol, benzaldehyde, 4‐methoxy benzyl alcohol and 4‐nitro benzaldehyde with sodium ferrate in the presence of copper nano particles adsorbed on montmorillonite K 10 under microwave irradiation. Aniline, p‐toluidine, phenol, catechol, resorcinol and p‐cresol polymerize under these conditions without exposing the mixture to microwaves. The one‐pot system does not require tedious separation of ferrate and is quick and environmentally benign. Copyright © 2007 John Wiley & Sons, Ltd.     

Fe-exchanged montmorillonite K10--the first heterogeneous catalyst for acylation of sulfonamides with carboxylic acid anhydrides

Fe-exchanged montmorillonite K10 catalyzes a highly efficient reaction between sterically and electronically diverse sulfonamides and carboxylic acid anhydrides to furnish N-acylsulfonamides in excellent yield and high selectivity. The catalyst can also be reused several times.     

Preferential solvation of indomethacin and naproxen in ethyl acetate + ethanol mixtures according to the IKBI method

The preferential solvation parameters of indomethacin and naproxen in ethyl acetate + ethanol mixtures are derived from their thermodynamic properties by using the inverse Kirkwood–Buff integrals method. It is found that both drugs are sensitive to solvation effects, so the preferential solvation parameter, δx_EA,D, is negative in ethanol-rich and ethyl acetate-rich mixtures but positive in compositions from 0.36 to 0.71 in mole fraction of ethyl acetate. It is conjecturable that in ethanol-rich mixtures, the acidic interaction of ethanol on basic sites of the analgesics plays a relevant role in the solvation. The more solvation by ethyl acetate in mixtures of similar co-solvent compositions could be due to polarity effects. Finally, the slight preference of these compounds for ethanol in ethyl acetate-rich mixtures could be explained as the common participation of basic sites in both solvents and the acidic site of ethanol. Nevertheless, the specific solute–solvent interactions remain unclear.     

Oxidative interactions of propene with acetic acid on a Pd-zeolite catalyst

The interactions between C₃H₆, AcOH and O₂ were investigated on 1.5 % Pd/TsVM catalysts prepared with and without addition of 15 % AcOK. Three states for surface oxygen on the promoted catalyst were distinguished. Two of them are involved in the oxidation of AcOH and C₃H₆ to CO₂ and H₂O, whereas the adsorbed species of the third type participates in the formation of allyl acetate. The O/Pd ratios for the promoted catalyst fall in the range from 3 to 4, the nonpromoted system is characterized by an O/Pd value of 0.5. IR-spectral data are used to discuss the reaction scheme for the formation of allyl acetate. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 1721–1726, October, 1993.     

Ions with a strong symmetric H-bond in solutions of sodium acetate in acetic acid

The multiple attenuated total reflection IR spectra of solutions of sodium acetate in acetic acid have been recorded in the range from 9000 to 4000 cm^–1. The CH₃COO^– anion and an acid molecule form be complex (CH₃COO...H...OOCCH₃) with a strong symmetric H-bond.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp, 1854–1857, July, 1996.     

Catalytic combustion of ethyl acetate over CeMnO_x and CeMnZrO_x compounds synthesized by coprecipitation method

Ce0.6Mn0.4O2 catalysts with different sources of manganese and Ce0.6-xZrxMn0.4O2 mixed oxide catalysts were prepared by coprecipitation method and were characterized by N2 adsorption-desorption,TPR,XRD,and XPS techniques.The activities of the prepared catalysts for ethyl acetate combustion,and the effects of calcination temperature and space velocity on catalytic activity were investigated.The results showed that partial replacement of Mn(NO3)2 with KMnO4 as sources of manganese could improve activities of catalysts.Ce0.45Zr0.15Mn0.4O2 catalyst exhibited the best catalytic activity and high thermal stability,e.g.,T90 could be still below 210℃ even if space velocity was up to 20000h-1.     

Expeditious reaction of ninhydrin with active methylene compounds on montmorillonite K10 clay

Abstract  Ninhydrin reacted expeditiously with thirteen active methylene compounds on montmorillonite K10 clay at room temperature to furnish, in 5 min, a Knoevenagel condensate in one case, aldols in six cases, aldol-derived cyclic hemiketals in three cases, and interesting products in the remaining three cases. Almost identical results were obtained, but faster, when the reactions were carried out in water on steam-bath. The structures of two novel products were also confirmed by single-crystal X-ray diffraction analysis. Graphical abstract        

疏水双功能介孔固体酸的合成及其在乙酸乙酯酯化反应中的应用

通过水热合成法一步合成了具有不同疏水基团－CH₃ 、－(CH₃)₂ 和－(CH₃)₃的双功能介孔固体酸SBA-15-SO₃H－(CH₃)_x催化剂。通过X射线粉末衍射(XRD)、N₂吸脱附、元素分析等方法对催化剂进行了表征,并在乙酸乙酯酯化反应中进行催化性能评价。结果表明,随着疏水前驱体中甲基数的增加,样品的疏水性增强。SBA-15-SO₃H-(CH₃)_x催化剂的催化活性随着疏水性的增强而提高,而具有较强疏水性的材料SBA-15-SO₃H-(CH₃)₃在反应中具有较高的催化性能。以SBA-15-SO₃H-(CH₃)₃为催化剂,酯化反应的最优条件为：温度为120℃,乙酸与乙醇摩尔比为4∶1,催化剂质量分数为1 %,反应时间为1h。在此条件下,乙醇的转化率和乙酸乙酯的选择性分别为93%和100%。     

蒙脱土K10-ZnCl2催化下研磨法合成二吲哚甲烷衍生物

蒙脱土K10固载_^ZnCl2是一个有效的环境友好催化剂. 在蒙脱土K10-ZnCl2催化下, 将吲哚与芳香醛混合在研钵中研磨2～8 min, 可得到收率为66%～97%的二吲哚甲烷衍生物. 该方法具有操作简便、反应条件温和、反应时间缩短、 对环境友好等优点.     

Phosphomolybdic acid supported on silica gel and promoted with alkali metal ions as catalysts for the esterification of acetic acid by ethanol

Different ratios of phosphomolybdic acid PMA supported on silica gel (1–30 wt%) and promoted with alkali metal hydroxide have been prepared by an impregnation method and calcinated at 350 °C for 4 h. The catalysts were characterized by thermogravimetry (TG), differential thermal analysis (DTA), X-ray diffraction, FT-IR spectroscopy and N₂ adsorption measurements. The surface acidity and basicity of the catalysts were determined by adsorption of pyridine and the dehydration–dehydrogenation of 2-propanol. The gas-phase esterification of acetic acid by ethanol was carried out in a conventional flow bed reactor. The results clearly revealed that among the PMA loading, the use of 10 wt% catalyst showed maximum yield of ethyl acetate. This catalyst also improved on addition of Na or K-hydroxide. These results were correlated with the structure and the acid–base properties of the prepared catalysts.