Preparation of NH_4ZrH(PO_4)_2·H_2O via solid-state reaction at low heat and its catalytic performance in the synthesis of butyl acetate

Nanocrystalline NH4ZrH（PO4）2·H2O was obtained by grinding ZrOC12·8H2O and （NH4）2HPO4 in the presence of surfactant PEG-400 via solid-state reaction at room temperature. The product NH4ZrH（PO4）2·H2O and its product of thermal decomposition were characterized using thermogravimetry and differential thermal analyses （TG/DTA）, Fourier transform infrared spectroscopy （FT-IR）, X-ray powder diffraction （XRD）, and transmission electron microscopy （TEM）. Nanocrystalline NHaZrH（PO4）2·H2O with an average particle size of 17 nm was obtained when the product was kept at80℃ for 3 h. Its crystalline framework was stable at temperatures below 250℃. In addition, the catalytic performance of NH4ZrH（PO4）2·H2O in the synthesis of butyl acetate was investigated. The results show that NH4ZrH（PO4）2·H2O behaved as an excellent heterogeneous catalyst in the synthesis of butyl acetate.

Synthesis of n-Butyl Acetate by Silica Loaded Cerous Sulfate Catalyst

Silica was used, as a catalyst carrier, to load cerous sulfate for catalyzing the synthesis of n-butyl acetate. The main purpose of this research was to explore the feasibility of silica in improving the decentrality and activity of the catalyst. The effects of molar ratio of butyl alcohol to acetic acid, the cerous sulfate loadings and the reaction time on the conversion of acetic acid were studied by single factor experiment method and orthogonal experiment method respectively. The refractive index (n20D) and molecular structure of the prepared n-butyl acetate were measured by Abbe Raefractometer and Fourier Transform Infrared spectroscope, respectively. The comparisons of the silica loaded and unloaded catalysts for catalyzing the synthesis of n-butyl acetate were made. The results showed that the suitable conditions for synthesizing n-butyl acetate were: molar ratio of butyl alcohol to acetic acid of 1.4∶1, use level of loaded cerous sulfate of 0.30 g and reaction time of 50 min, respectively. The maximum conversion of acetic acid for the silica loaded catalyst reached 98.62% which was 12.32% and 16.43% higher than those for the unloaded catalysts reported in literatures, but the use level of cerous sulfate for the former was much less than those for the latters under similar optimal technical conditions. The silica was proved to be a good catalyst carrier for enhancing decentrality and activity of the catalyst and increasing the conversion of acetic acid. The repentance of the silica loaded cerous sulfate was also investigated in the experiment.

A Novel Process Using Ion Exchange Resins for the Coproduction of Ethyl and Butyl Acetates

Before proposing an innovative process for the coproduction of ethyl and butyl acetates, the individual syntheses of ethyl acetate and butyl acetate by two different routes were first studied. These syntheses involved the reaction of ethanol or n-butanol with acetic acid or acetic anhydride in the presence of ion exchange resins: Amberlyst 15, Amberlyst 16, Amberlyst 36 and Dowex 50WX8. Kinetic and thermodynamic studies were performed with all resins. The lowest activation energy (Ea) value was obtained with Dowex 50WX8, which was identified as the best-performing resin, able to be reused at least in four runs without regeneration. The presence of water-azeotropes during the synthesis of ethyl acetate makes its purification difficult. A new strategy was adopted here, involving the use of ethanol and acetic anhydride as the starting material. In order to minimize acetic acid as co-product of this reaction, a novel two-step process for the coproduction of ethyl and butyl acetates was developed. The first step involves the production of ethyl acetate and its purification. Butyl acetate was produced in the second step: n-butanol was added to the mixture of acetic acid and the resin remaining after the first-step distillation. This process yields ethyl acetate and butyl acetate at high purity and shows an environmental benefit over the independent syntheses by green metrics calculation and life cycle assessment.

Alternative technology for the recovery of butyl acetate with low concentration:high capacity adsorbent and high efficiency adsorption

Industrial pharmaceutical wastewater usually contains butyl acetate(BA)with a concentration of 1 wt%-7 wt%,and the traditional method for BA recovery is distillation with high energy consumption.Adsorption method is developed to recover BA with low concentration for the high efficiency and low energy consumption.Medium polar polyacrylate resins with macroporous structure of 233.1 nm and average particle size of about 526.5μm are successfully synthesized by suspension polymerization and used for the BA adsorption and desorption.The maximum adsorption capacity reaches 171.1 mg g^(-1)with relative standard deviation(RSD)value of 0.2%,which is more than twice the results in the literature.The BA desorption rate is 97.0%at 100℃with RSD value of 0.4%,and the resins are beneficial to the reuse in the adsorption-desorption cycle.The adsorption thermodynamics and kinetics are investigated,and the BA adsorption is a spontaneous and endothermic process with the increase of disorder degree.This process is mainly contributed by physical absorption and agree well with Freundlich model and pseudo-first-order adsorption kinetic model.The adsorption method avoids boiling a large amount of wastewater and hopefully provides a novel alternative technology for the BA recovery.

Effects of metal and acidic sites on the reaction by-products of butyl acetate oxidation over palladium-based catalysts

Catalytic oxidation is widely used in pollution control technology to remove volatile organic compounds. In this study, Pd/ZSM-5 catalysts with different Pd contents and acidic sites were prepared via the impregnation method. All the catalysts were characterized by means of N2 adsorption- desorption, X-ray fluorescence （XRF）, HE temperature programmed reduction （H2-TPR）, and NH3 temperature programmed desorption （NH3-TPD）. Their catalytic performance was investigated in the oxidation of butyl acetate experiments. The by-products of the reaction were collected in thermal desorption tubes and identified by gas chromatography/mass spectrometry. It was found that the increase of Pd content slightly changed the catalytic activity of butyl acetate oxidation according to the yield of CO2 achieved at 90%, but decreased the cracking by-products, whereas the enhancement of strong acidity over Pd-based catalysts enriched the by-product species. The butyl acetate oxidation process involves a series of reaction steps including protolysis, dehydrogenation, dehydration, cracking, and isomerization. Generally, butyl acetate was cracked to acetic acid and 2- methylpropene and the latter was an intermediate of the other by-products, and the oxidation routes of typical by-products were proposed. Trace amounts of 3-methylpentane, hexane, 2-methylpentane, pentane, and 2-methylbutane originated from iso4merization and protolysis reactions.

DMS AND ^(13)C NMR STUDIES ON THE COMPATIBILITY AND DYNAMICS OF LATEX BIDIRECTIONAL IPNS AND LATEX IPN OF PVAc/PBA

The compatibility and dynamics of latex bidirectional/nterpenetrating polymer networks (LBIPNs) and latex IPN(LIPN) of poly(vinyl acetate)(PVAc) and poly (butyl acrylate )(PBA) are investigated by means of dynamic mechanical spectroscopy (DMS) and nuclear magnetic resonance (NMR) techniques. The results of DMS show that the compatibility of the LBIPNs is much better than that of the corresponding LIPN and depends to, a large extent on the distribution of PVAc both in the core and in the shell. The results of NMR measurements indicate that the rotational correlation times of the side- groups of PBA in the LBIPN are longer than those in the LIPN. The relation between the ^(13)C linewidths of PBA and temperature is also discussed.