微波干法合成查尔酮

查尔酮的化学名为1,3-二苯基丙烯酮,以它为母体的天然化合物存在于红花、甘草等多种天然植物中,是植物体内合成黄烷酮的重要中间体,其自身也具有抗过敏、抗溃疡、抗肿瘤等药理作用[1-3].     

超声法制备掺钡纳米氧化镁及其负载钌基氨合成催化剂的催化性能

采用超声技术制备掺钡纳米氧化镁,并以其为载体,以Ru3(CO)12 为前驱体,采用浸渍法制备了一系列钌基氨合成催化剂. 采用场发射扫描电镜、 X射线衍射和N2物理吸附等表征手段,考察了催化剂的表面形貌、物相和表面织构性质. 在400～450 ℃的条件下评价了催化剂对氨合成的催化活性. 结果表明,以超声技术制备的掺钡纳米氧化镁有较大的比表面积和较规则的孔道结构,并增强了钡、镁之间的相互作用,使钡更均匀地分散于载体中,极大地提高了钡的促进作用,从而使其负载的钌基催化剂的活性大幅度提高. 当超声作用为时间30 min时,在10 MPa, 425 ℃和空速 10 000 h-1 的条件下, 4%Ru/Ba-MgO催化剂上的氨合成反应速率达到61.02 mmol/(g·h).     

NiFe2O4/g-C3N4 heterojunction composite with enhanced visible-light photocatalytic activity

Spinel structure nickel ferrite (NiFe₂O₄) doped graphitic carbon nitride (g-C₃N₄) photocatalyst NiFe₂O₄/g-C₃N₄ was synthesized by the coprecipitation route to enhance the photocatalytic activity for the visible-light driven degradation of methyl orange. The NiFe₂O₄ doping content is responsible for the microstructure and photocatalytic activity of NiFe₂O₄/g-C₃N₄ samples. Compared with pure NiFe₂O₄ and g-C₃N₄, the 2-NiFe₂O₄/g-C₃N₄ composite with NiFe₂O₄ doping of 2.0 wt% exhibited excellent photocatalytic activity and superior stability after five runs for degrading methyl orange under visible light irradiation. The catalytic activity of 2-NiFe₂O₄/g-C₃N₄ sample produced using the coprecipitation route was higher than those of conventional 2-NiFe₂O₄/g-C₃N₄ bulks prepared by the impregnation approach. The prepared samples for the photocatalytic degradation of methyl orange followed pseudo-first-order reaction kinetics. It’s ascribed to the synergistic effect between NiFe₂O₄ and g-C₃N₄, which can inhibit the recombination of photoexcited electron-hole pairs, accelerate photoproduced charges separation, and enhance the visible light absorption.     

Assessment of Microwave Effect on Polymerization Conducted under ARGET ATRP Conditions

A comprehensive kinetic model based on the method of moments is developed for understanding the kinetics of activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) under microwave irradiation. Both the experimental data and the simulation results show that the polymerization under microwave irradiation is much faster than the thermal polymerization. Simulation results indicate that the acceleration of polymerization can be attributed to the increase of propagation rate coefficient and the radical generation by microwave irradiation. Kinetic behaviors, such as the effect of catalyst concentration and initial initiator, are investigated in detail. Results show that the catalyst concentration has negligible influence on polymerization rate while the initiator concentration can affect both the molecular weight and the reaction rate. In conclusion, this work thoroughly investigates the kinetic mechanism of ARGET ATRP under microwave irradiation, providing both theoretic and experimental supports to improve the product property of polymer materials.     

中子辐照对钒合金强塑性的影响及其温度效应

研究了经中子辐照和未经辐照钒合金在不同温度下的拉伸强塑性，提出了一个拉伸过程卸载后再拉伸的模型来研究经中子辐照和未经辐照合金的拉伸变形规律。结果表明，合金经中子辐照后引起的变形强化大小与未经辐照的相似，此后的塑性变形特征几乎一致。对于V4Cr4Ti合金，为防止突发断裂事故，辐照后的屈服强度应低于400MPa。     

Microwave-assisted asymmetric ring opening of meso-epoxides with aromatic amines catalyzed by a Ti-S-(−)-BINOL complex

Catalytic asymmetric ring opening of cyclohexene oxide and meso-stilbene oxide with anilines was catalyzed by a Ti-(S)-(−)-BINOL complex to afford β-amino alcohols in high yield (up to 95%) and good enantioselectivities (ee up to 55%) under microwave irradiation. The reaction using a microwave was found to be 10 times faster than traditional oil-bath heating with retention of enantioselectivity.     

DAMAGE OF SILICONE RUBBER INDUCED BY PROTON IRRADIATION

In this paper, the damage to methyl silicone rubber induced by irradiation with protons of 150 keV energy wasstudied. The surface morphology, tensile strength, Shore hardness, cross-linking density and glass transition temperaturewere examined. Positron annihilation lifetime spectrum analysis (PALS) was perfomed to reveal the damage mechanisms ofthe rubber. The results showed that tensile strength and Shore hardness of the rubber increased first and then decreased withincreasing irradiation fluence. The PALS characteristics τ_3 and I_3, as well as the free volume V_f, decreased with increasingirradiation fluence up to 10~(15) cm~(-2), and then increased slowly. It indicates that proton irradiation causes a decrease of freevolume in the methyl silicone rubber when the fluence is less than 10~(15)cm~(-2), while the free volume increases when thefluence is greater than 10~(15)cm~(-2). The results on cross-linking density indicate that the cross-linking induced by protonirradiation is dominant at smaller proton fluences, increasing the tensile strength and Shore hardness of the rubber, while thedegradation of rubber dominates at greater fluence, leading to a decrease of tensile strength and Shore hardness.     

Regioselective annelation of 3-(prop-2-ynylsulfanyl)-1,2,4-benzotriazine to thiazolo[2,3-c][1,2,4]benzotriazine

Summary Thiosemicarbazide reacted with 1,2-diaminobenzene to give 1,2-dihydro-3-thioxo-1,2,4-benzotriazine (1) in fairly good yield in a solvent free reaction under microwave irradiation.1 was condensed with prop-2ynyl bromide in the presence of sodium methoxide to afford the corresponding 3-(prop-2-ynylsulfanyl)-1,2,4-benzotriazine (5). Transformation of5 to 3-methylidene-2,3-dihydro-9H-thiazolo[2,3-c][1,2,4]benzotriazine (6) was performed in the presence of a palladium salt.

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Regioselektive Anellierung von 3-(prop-2-inylsulfanyl)-1,2,4-benzotriazin zu Thiazolo[2,3-c][1,2,4]benzotriazin

Zusammenfassung Thiosemicarbazid reagierte mit 1,2-Diaminobenzol ohne Lösungsmittel und unter Bestrahlung mit Mikrowellen in guter Ausbeute zu 1,2-Dihydro-3-thioxo-1,2,4-benzotriazin (1), welches in Gegenwart von Natriummethoxid mit Prop-2-inylbromid zum entsprechenden 3-(Prop-2-inylsulfanyl)-1,2,4-benzotriazin (5) kondensiert wurde. Die Umsetzung von5 zu Methyliden-2,3-dihydro-9H-thiazolo[2,3-c] [1,2,4]benzotriazin (6) gelang unter Palladiumkatalyse.