从α－蒎烯直接催化酯化高选择性地合成乙酸正龙脑酯的研究－催化剂与反应机理初探

本文提出了新的硼酸类催化剂体系ＨＢ，用该体系对α－蒎烯与无水乙酸相互作用直接合成乙酸正龙脑酯作了较系统的研究。反应得到两种系列产物－酯化产物和异构化产物，酯化产物主要是乙酸正龙脑酯，葑醇酯和松油酯，异构化产物主要是莰烯、烯和松油烯等，总酯化产率为５０％以上，其中乙酸正龙脑酯为２０％以上，是至今从α－蒎烯直接合成乙酸正龙脑酯的最好结果。通过对产物的￣１ＨＮＭＫ图谱分析及动力学考察，确证反应主产物是正龙脑酯而不是异龙脑酯。文章对Ｈ＿２ＳＯ＿４、ＨＣｌＯ＿４、多聚磷酸（ＰＰＡ）和杂多酸（１２－磷钨酸）等催化剂进行了实验考察、对比和评述，表明了自制的ＨＢ催化剂体系具有高选择性合成乙酸正龙脑酯的显著优点，并对其反应机理作了初步探讨。     

Surface solid-state interactions in copper-nickel-cement catalysts for hydrogenation of oxygen

The surface phase composition of alumocalcium cement-supported CuO and CuO-NiO catalysts prepared by chemical mixing has been studied using the method of thermo-vacuum curves of electric conductivity. The deactivation of these catalysts due to overheating to 800 °C under conditions of hydrogenation of oxygen is rationalized by the partial extraction of CuO (and NiO) from the stabilizing structure of the support solid solutions and by sintering of the extracted oxides and the reduced metallic phase. Complete regeneration of the CuO-NiO-talum catalysts can be achieved if a considerable amount (20%) of copper hydroxocarbonate is added.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1559–1562, September, 1994.     

The high-temperature durability of Rh-free threeway catalysts used for automoble emission control

The high-temperature durability of cordierite honeycomb Rh-free three-way catalysts (TWC) containing additives has been studied by calcining catalysts at various temperatures in the interval of 600≈1100°C. The three-way performances of these catalysts were evaluated for the reaction of carbon monoxide(CO), hydrocarbon(HC) and nitrogen oxides(NOx) at given conditions by using a fixed bed reactor. The results show that after Rh-free TWC are thermally aged in air at 1100°C for 5h and 950°C for 104 h, the TWC still have better three-way activity compared with Rh-containing TWC.     

固体磷酸催化剂的活性相

研究了固体磷酸催化剂活性与其自由磷酸聚合态及磷酸硅晶型的关系，指出高活性磷酸催化剂应具备的条件，即自由磷酸中应为正磷酸和焦磷酸的混合物，结合态磷应具有“Ｃ”晶型。     

New stage in living cationic polymerization: An array of effective Lewis acid catalysts and fast living polymerization in seconds

Our recent extensive research on Lewis acid catalysts with a weak base for the cationic polymerization of vinyl ethers led to unprecedented living reaction systems: fast living polymerization within 1–3 s; a wide choice of metal halides containing Al, Sn, Fe, Ti, Zr, Hf, Zn, Ga, In, Si, Ge, and Bi; and heterogeneously catalyzed living polymerization with Fe₂O₃. The use of added bases for the stabilization of the propagating carbocation and the appropriate selection of Lewis acid catalysts were crucial to the success of such new types of living polymerizations. In addition, the base‐stabilized living polymerization allowed the quantitative synthesis of star‐shaped polymers with a narrow molecular weight distribution via polymer‐linking reactions and the precision synthesis and self‐assembly of stimuli‐responsive block copolymers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1801–1813, 2007.     

CeO2-ZrO2-Y2O3对Pt-Rh型三效催化剂性能的影响

采用共沉淀法技术制备了Ce0.35Zr0.55Y0.10固溶体,并对其进行了比表面积、储氧量的测试和XRD的表征.将其用于低贵金属Pt-Rh型三效催化剂的制备,考察了CeO2-ZrO2-Y2O3对三效催化剂性能的影响.结果表明,Ce0.35Zr0.55Y0.10具有与Ce0.50Zr0.50O2相似的立方结构和相近的储氧量,经高温(1000 ℃)后仍能保持较大的比表面积(38.66 m2·g-1).和含Ce0.50Zr0.50O2的三效催化剂相比,含CeO2-ZrO2-Y2O3的三效催化剂经高温老化后,C3H8,CO,NO仍具有较高的转化率和较低的起燃温度.     

Dirhodium(II)-catalyzed carbonyl ylide generation. Stereoelectronic control in dioxolane formation

The combination of ethyl diazoacetate with aryl aldehydes in the presence of copper(I) or rhodium(II) catalysts results in the formation of 1,3-dioxolane products in moderate to good yields. These reactions occur through a pathway that involves ylide intermediates. Catalyst-dependent diastereocontrol is observed and suggests that metal-associated ylides are involved in the product-determining step. The influence of aryl aldehyde substituents has been determined. Current address. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 961–965, May, 1998.     

Pd(0)‐catalyzed polyaddition of bifunctional vinyloxiranes with 1,3‐dicarbonyl compounds: The synthesis of polymers containing hydroxy and carbonyl groups

The palladium(0)‐catalyzed polyaddition of bifunctional vinyloxiranes [1,4‐bis(2‐vinylepoxyethyl)benzene ( 1a ) and 1,4‐bis(1‐methyl‐2‐vinylepoxyethyl)benzene ( 1b )] with 1,3‐dicarbonyl compounds [methyl acetoacetate ( 4 ), dimethyl malonate ( 6 ), and Meldrum's acid ( 8 )] was investigated under various conditions. The polyaddition of 1 with 4 was carried out in tetrahydrofuran with phosphine ligands such as PPh₃ and 1,2‐bis(diphenylphosphino)ethane (dppe). Polymers having hydroxy, ketone, and ester groups in the side groups ( 5 ) were obtained in good yields despite the kinds of ligands employed. The number‐average molecular weight value of 5b was higher than that of 5a . The polyaddition of 1b and 6 was affected by the kinds of ligands employed. The corresponding polymer 7b was not obtained when PPh₃ and 1,2‐bis(diphenylphosphino)ferrocene were used. The polyaddition was carried out with dppe as the ligand and gave polymer 7b in a good yield. The molecular weight of the polymer obtained from 1b and 8 was much higher than those of polymers 5b and 7b . The polyaddition with Pd₂(dba)₃ · CHCl₃/dppe as a catalyst (where dba is dibenzylideneacetone) produced polymer 9b in a 92% yield (number‐average molecular weight = 45,600). The stereochemistries of all the obtained polymers were confirmed as an E configuration by the coupling constant of the vinyl proton. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 2487–2494, 2002     

Influence of the texture of chromia catalysts on their activity in synthesis of 2-methylthiophene

The texture of Cr₂O₃-K₂O/Al₂O₃catalysts containing oxides of rare earth elements (REE) was studied. The catalysts are used for the synthesis of 2-methylthiophene by the reaction of H₂S with n-pentane or piperilene. The heterocyclization of n-pentane is a consecutive reaction involving a step of dehydrogenation of initial hydrocarbon. At this step the texture of the catalyst affects the yield of 2-methylthiophene. The yield of 2-methylthiophene obtained from piperilene and I₂S is independent of the catalyst texture.     

Selective oxidation of octadecan-1-ol to octadecanoic acid over Co3O4/SiO2 catalysts

Factors (reaction temperature, reaction time, flow rate of oxygen, amount of catalyst, etc.) influencing the catalytic properties of Co₃O₄/SiO₂catalyst in the oxidation octadecan-1-ol to octadecanoic acid were investigated. The catalysts were characterized by means of XRD, FT-IR and N₂-adsorption. The experimental results indicate that under the optimal condition the selectivity to octadecanoic acid reached 97.5 % over 5 % Co₃O₄/SiO₂ catalyst.This revised version was published online in December 2005 with corrections to the Cover Date.