Formation Mechanism of Hydrous-Zirconia Particles Produced by Hydrolysis of ZrOCl2 Solutions: II

The primary and secondary particle sizes of monoclinic hydrous-ZrO₂ particles produced by the hydrolysis of various ZrOCl₂ solutions, with and without the addition of NaCl, CaCl₂, or AlCl₃, were measured using X-ray diffraction and transmission electron microscopy in order to clarify the formation mechanisms of primary and secondary particles. The primary particle size of hydrous ZrO₂, under a constant ZrOCl₂ concentration, decreased monotonously with increasing Cl⁻-ion concentration. On the contrary, the secondary particle size increased monotonously with increasing Cl⁻-ion concentration. The present experimental results revealed that the primary and secondary particle sizes of hydrous ZrO₂ are controlled primarily by the concentrations of H⁺ and Cl⁻ ions produced during hydrolysis, and are independent of the type of added metal ions. The formation mechanisms of the primary and secondary particles of hydrous ZrO₂ were determined on the basis of the present experimental results.     

均匀设计在负载型酯化催化剂制备中的应用

:以离子交换树脂为载体 ,用均匀设计方法考查了负载型酯化催化剂制备中负载金属盐用量 ,负载温度 ,负载时间和载体粒度等因素对催化剂活性的影响。获得的回归方程能较好地反映各因素与催化剂活性的关系。在优化的实验条件下制备的负载型催化剂 ,对乙酸和乙醇的酯化反应具有较高的催化活性。在用量为反应体系中醋酸量的 5%时 ,反应 1 h,酯的转化率达 36.56%。比没有进行负载处理的离子交换树脂 ,在同样的条件下酯的转化率提高 1 7.32个百分点。     

琥珀酸二异辛酯磺酸钠的制备

介绍了一种在常压、无外加相转移催化剂的条件下制备琥珀酸二异辛酯磺酸钠的新方法。研究了合成标题产物中磺化反应的主要影响因素 ,并得出该反应的优惠工艺条件     

二氢突厥酮的合成

α、β-二氢突厥酮是保加利亚玫瑰油的主要香气物质,云南省化工研究院以环柠檬醛为起始原料,采用新型催化剂得到了这两种二氢突厥酮产品。经专家鉴定,该技术在国内处于领先水平。该文对其中的假性二氢突厥醇的制备条件进行了详细的讨论,并简述了二氢突厥酮产品的精制方法。     

Conversion of methane to benzene over Mo2C and Mo2C/ZSM-5 catalysts

The activation and dehydrogenation of CH₂ on Mo₂C and MO₂C/ZSM-5 have been investigated under non-oxidizing conditions. Unsupported Mo₂C exhibited very little activity towards methane decomposition at 973 K. The main reaction pathway was the decomposition of methane to give hydrogen and carbon with a trace amount of ethane. Mixing Mo₂C with ZSM-5 support somewhat enhanced its catalytic activity, but did not change the products of the reaction. A dramatic change in the product formation occurred on partially oxidized Mo2C/ZSM-5 catalyst; besides some hydrocarbons benzene was produced with a selectivity of 70–80% at a conversion of 5–7%. Carburization of highly dispersed MoO₃ on ZSM-5 also led to a very active catalyst: the conversion of methane at the steady state was 5–6% and the selectivity of benzene formation was 85%.This laboratory is a part of the Center for Catalysis, Surface and Material Science at the University of Szeged.     

有机相中壳聚糖-海藻酸固定化脂酶的特性

研究了壳聚糖 海藻酸固定化脂酶在有机相反应中的稳定性与活性。考察了凝胶时间、壳聚糖浓度及壳聚糖分子质量对固定化脂酶包埋率与活性的影响 ,确定了适宜 pH值与批反应时间。同时讨论了溶剂极性和操作时间对固定化酶稳定性的影响。测定了固定化脂酶水解橄榄油反应的动力学参数。结果表明 ,壳聚糖 海藻酸聚电解质膜可提高固定化酶的包埋率与稳定性     

N-苯基马来酰亚胺的应用与合成

叙述了N -苯基马来酰亚胺的用途及合成方法。通过分析ABS及PVC的市场前景 ,提出了在国内开发N -苯基马来酰亚胺的必要性和紧迫性。     

Catalytic Performance of B2O3/TiO2–ZrO2 for Vapor-Phase Beckmann Rearrangement of Cyclohexanone Oxime: The Effect of Boria Loading

A series of boria catalysts supported on titania–zirconia mixed oxide (B₂O₃/TiO₂–ZrO₂) with different boria loadings (8–20 wt%) were prepared and characterized by X-ray diffraction, adsorption of nitrogen, ¹¹B magic angle spinning (MAS) NMR measurements and temperature-programmed desorption (TPD) of ammonia. The catalytic performance of B₂O₃/TiO₂–ZrO₂ for vapor-phase Beckmann rearrangement of cyclohexanone oxime to -caprolactam was studied at 300°C. It was found that the lactam selectivity increased with increasing of boria loading, whereas a maximum oxime conversion was obtained at the boria loading of 12 wt%. The acid sites of medium strength on the surface of the catalyst play an important role in the selective formation of lactam.     

Deterioration Mode of Barium-Containing NOx Storage Catalyst

Barium-containing NO _x storage catalyst showed serious deactivation under thermal exposure at high temperatures. To elucidate the thermal deterioration of the NO _x storage catalyst, four types of model catalyst, Pt/Al₂O₃, Ba/Al₂O₃, Pt–Ba/Al₂O₃, and a physical mixture of Pt/Al₂O₃ + Ba/Al₂O₃ were prepared and their physicochemical properties such as BET, NO TPD, TGA/DSC, XRD, and XPS were evaluated while the thermal aging temperature was increased from 550 to 1050°C. The fresh Pt–Ba/Al₂O₃ showed a sorption capacity of 3.35 wt%/g-cat. but the aged one revealed a reduced capacity of 2.28 wt%/g-cat. corresponding to 68% of the fresh one. It was found that this reduced sorption capacity was directly related to the deterioration of the NO _x storage catalyst by thermal aging. The Ba on Ba/Al₂O₃ and Pt–Ba/Al₂O₃ catalysts began to interact with alumina to form Ba–Al solid alloy above 600°C and then transformed into stable BaAl₂O₄ having a spinel structure. However, no phase transition was observed in the Pt/Al₂O₃ catalyst having no barium component, even after aging at 1050°C.     

两种工艺制备聚醚多元醇ZS-4110Ⅱ的比较

通过对在两种不同催化合成工艺条件下生产聚醚ZS-4110Ⅱ的研究,比较了该产品在成本、收集、质量指标及应用性能等方面的差异。二甲胺催化生产的聚醚ZS-4110ⅡA在生产效率、制造成本等方面有明显的优势,而氢氧化钾催化生产的聚醚ZS-4110ⅡK在产品的内在质量以及应用性能方面要优于胺工艺聚醚。