杂多酸化学吸收从天然气中脱除H_2S回收硫磺的研究

研究开发了利用杂多酸脱除天然气中H2S并回收硫磺的新工艺实验结果表明，H2S的脱除效率与溶液酸度、杂多酸浓度、H2S浓度以及吸收温度、停留时间均有关系．吸收的最佳酸度为0.1kmol／m3H2SO4，此时H2S的去除率可达99％以上．通过对比纯硫磺和H2S转化物的热重分析和微分差热分析图谱，确证了在吸收过程中H2S被氧化为硫磺，杂多酸被还原为单电子杂多兰．杂多兰可被Cl2、Fe3+和NO2氧化而再生．     

Highly efficient synthesis of coumarin derivatives in the presence of H14[NaP5W30O110] as a green and reusable catalyst

A variety of heteropolyanions including: Keggin, Dawson, Preyssler, mixed addenda and sandwich types, catalyzed the formation of 4-methylnaphtho-(1,2-b)-pyran-2-one (coumarin) from the condensation of α-naphthol and ethylacetoacetate in a solvent free system and under heating conditions. Our data vividly indicate that sodium30–tungsto pentaphosphate, [NaP₅W₃₀O₁₁₀]¹⁴⁻, which so-called Preyssler’s anion, with high hydrolytic (pH 0–12) and thermal stability is the catalyst of choice. This catalyst catalyzed the synthesis of other coumarin derivatives in high yields and good selectivity.     

Cesium salt of a heteropolyacid in nanotubular channels and on the external surface of SBA-15 crystals: preparation and performance as acidic catalysts

The Cs-salt of heteropolyacid with stoichiometry Cs_2.5H_0.5PW₁₂O₄₀ (CsHPW) was deposited selectively at the external surface of the SBA-15 silica microcrystals, inside its mesoporous channels and simultaneously at both location modes. The structure, texture and performance of these CsHPW/SBA-15 composites were compared with that of a reference bulk salt of the same composition. Location of CsHPW salt on the external surface of SBA-15 microcrystals leads to disintegration of its agglomerates increasing acidity of the catalytic phase. A novel preparation strategy consisting of grafting the basic Cs-species at the internal pores surface of SBA-15 stabilized the CsHPW phase inside the channels in form of 5–8 nm nanocrystals at 30–70 wt.% loadings. The catalytic tests demonstrated that insertion of the CsHPW catalytic phase inside the nanotubular channels of SBA-15 in combination with location of an additional amount of this phase at the external surface of SBA-15 microcrystals allows to increase the specific activity of this phase in MTBE synthesis, propionylation of anisole and alkylation of catechol with t-butanol by a factor of 1.5–3. This level of specific activity in combination with high total loading of catalytic phase >60 wt.% permit to get composite catalytic materials with catalytic activity higher by a factor of 1.2–1.5 with respect to the bulk CsHPW catalyst and stabilizing the catalytic phase against colloidization in polar media.     

Recent progress in the practical applications of heteropolyacid and perovskite catalysts: Catalytic technology for the sustainable society

Recent progresses in practical applications of (i) supported heteropolyacid and (ii) Pd/perovskite catalysts are described. (i) Two industrial catalytic processes, ethyl acetate and acetic acid syntheses both from ethylene, utilize silicotungstic acid, alone and together with Pd, respectively, carefully supported on silica, and exhibit high performance from green chemical and economical viewpoints. The layer structure of heteropolyacid on silica and physical properties of silica are among the key factors of the high performance. (ii) Pd/perovskite catalyst is applied for the treatment of automotive emission, where the catalyst life is very much elongated by embedding Pd into the perovskite lattice and hence resulted in much reduced usage of Pd. These are good examples of green catalytic technology that will contribute to the sustainable society.     

Preparation and photocatalytic activity of Keggin-ion tungstate and TiO2 hybrid layer-by-layer film composites

Keggin ions (PW₁₂O₄₀³⁻ (PW₁₂), SiW₁₂O₄₀⁴⁻ (SiW₁₂), H₂W₁₂O₄₀⁶⁻ (H₂W₁₂)) and TiO₂ hybrid thin films were prepared using the layer-by-layer method. Their photocatalytic activities were investigated using gaseous 2-propanol decomposition. All films were transparent in the visible wavelength range. For 2-propanol decomposition, H₂W₁₂ was the most effective for the combination with TiO₂ despite having the smallest TiO₂ deposition amount. The photocatalytic activity of the PW₁₂–TiO₂ hybrid film was increased 2.3 times by visible light with UV illumination. This increase was less remarkable for hybrid films of other Keggin ions, suggesting that the visible light excitation of reduced PW₁₂ plays an important role in the enhancement of 2-propanol decomposition.     

MTBE催化技术

介绍了MTBE工业化生产中 ,合成反应过程的一般特点。对于MTBE合成反应的催化机理 ,目前生产装置中所使用的主要催化剂大孔径强酸性阳离子交换树脂的主要性能指标 ,以及这类催化剂的使用性能和操作参数的关系进行了论述 ,分析了实际生产中导致催化剂失活的影响因素和失活过程。对目前尚未工业化的新型催化剂沸石催化剂、杂多酸催化剂的主要优缺点进行了探讨     

H_5GaMo_6W_6O_(40)·14H_2O及其钐盐的合成与表征

首次采用分步酸化、分步加料及乙醚萃取法合成了钼钨镓酸Ｈ５ＧａＭｏ６Ｗ６Ｏ４０．１４Ｈ２Ｏ，并用复分解法合成了钐的钼钨镓酸盐ＳｍＨ２ＧａＭｏ６Ｗ６Ｏ４０．１５Ｈ２Ｏ．用元素分析、电位滴定、红外光谱、紫外光谱、Ｘ射线粉末衍射和热分析等方法对合成产物进行了表征．结果表明，合成产物具有Ｋｅｇ－ｇｉｎ结构，且具有很高的热稳定性．     

杂多酸(盐)用于油品氧化脱硫的研究进展

综述了杂多酸(盐)催化剂的结构特征及催化特性,包括磷钨酸(盐)体系、磷钨酸(盐)/季铵盐体系、磷钨酸季铵盐体系、负载型磷钨酸体系、磷钼酸(盐)体系、杂原子改性杂多酸体系等。介绍了几种类型杂多酸(盐)在油品氧化脱硫中的应用进展,并指出了其现存的问题及今后的研究方向。     

Petrochemicals from ethanol over a W-Si-based nanocomposite bidisperse solid acid catalyst

Very high ethylene selectivity values approaching 100% and very high ethanol conversion values approaching 85% were obtained in dehydration of ethanol over a new W-silicate-based nanocomposite catalyst having both meso and macropores and containing a W/Si atomic ratio of 0.85. Silicotungsticacid was successfully incorporated into the catalyst structure following a one-pot hydrothermal synthesis procedure. This catalyst is highly stable and does not loose activity in polar solvents and it has a sufficiently high surface area for catalytic applications. Calcination temperature of the catalyst was found to have a very significant effect on the catalyst structure and also on its catalytic performance in ethanol dehydration. Maximum selectivity of the second major reaction product diethylether was obtained as 0.7 at 200 °C, with the catalyst which was calcined at 400 °C. Very high ethylene and diethylether yield values obtained in this study at different reaction conditions are highly promising for the production of petrochemicals from ethanol.