Revealing the catalytic mechanism of an ionic liquid with an isotope exchange method

The alkylation mechanism catalyzed by an ionic liquid （as a Lewis acid） may be different from the traditional alkylation mechanism catalyzed by Br nsted acid,especially as their initiation steps are still not clear.In this paper,an isotope exchange method is used to investigate the catalytic mechanism of AlCl 3 /butyl-methyl-imidazolium chloride ionic liquid in the alkylation of benzene with 1-dodecene.The proposed catalytic mechanism was confirmed by analysis of ionic liquid before and after reaction and of the alkylation products of deuterated benzene （C 6 D 6） with 1-dodecene.The proposed mechanism consists of the equilibrium reaction between [Al 2 Cl 7 ] ＋H ＋ and [AlHCl 3 ] ＋ ＋[AlCl 4 ],in which the Br nsted acid [AlHCl 3 ] ＋ is supplied by the reaction of 2-H on the imidazolium ring and [Al 2 Cl 7 ].The alkylation reaction is initiated by the Br nsted acid [AlHCl 3 ] ＋ which reacts with 1-dodecene to form a carbonium ion,then the carbonium ion reacts with benzene to form an unstable σ complex,leading to the formation of 2-phenyldodecane.

Preparation of new sunscreen materials Ce_(1-x)Zn_xO_(2-x) via solid-state reaction at room temperature and study on their properties

Superfine cerium-zinc oxides Ce1-xZnxO2-x with x = 0, 0.1, 0.3, 0.5, and 1.0 were obtained by grinding Ce（SO4）2·4H2O, ZnSO4·7H2O and NH4HCO3 under the condition of surfactant PEG-400 being present at room temperature, washing the mixture with water to remove soluble inorganic salts, drying at 80°C, and calcining.The precursor and its calcined samples were characterized using thermogravimetry and differential thermal analyses（TG/DTA）, UV-vis absorption spectroscopy, X-ray powder diffraction（XRD）, and scanning electron microscopy（SEM）.The results showed that superfine Ce1-xZnxO2-x behaved as an excellent UV-shielding material.The ZnO-doped CeO2 can facilitate the formation of crystalline state CeO2.The catalytic ability of products used in air oxidation of castor oil was investigated.The results showed that the catalytic abilities of products decreased with increasing zinc amount.

聚苯乙烯的氘化及其性能研究

采用聚苯乙烯(PS)催化氘化技术,在使苯环被氘化饱和的基础上,成功地制备出了部分氘化的聚环己基乙烯(D-PVCH,C8H8D6)。用傅里叶红外光谱仪、核磁共振仪对D-PVCH的结构进行了表征,结果表明与目标产物吻合,即苯环被氘饱和转化为环己基,氘代率为41.5%。采用差式扫描量热仪和热重分析仪分析了D-PVCH的热性能,结果表明D-PVCH的玻璃化转变温度为125℃,5%失重温度为403℃。另外,D-PVCH可溶于常见溶剂,如石油醚、环己烷和甲苯等。与PS相比,D-PVCH具有较好的热稳定性和良好的溶解性能。

Synthesis, Thermal, Electrical and Catalytic Studies of Some Transition Metal Polychelates of Bis-bidentate Schiff Base

Polychelates of Mn（Ⅱ）, Fe（Ⅱ）, Co（Ⅱ）, Ni（Ⅱ）, Cu（Ⅱ）, Zn（Ⅱ） and Cd（Ⅱ） with the bis salen-type ligand derived from 4,4＇-bis[（salicylaldehyde-5）azo]biphenyl and 1,4-diaminobutane have been synthesized. All the polychelalls have been characllrized by elemental analysis, magnetic susceptibility measurements, IR, electronic spectra and thennogravirncuic studies. All the complexes isolated in solid stall are dark coloured and insoluble in water and common organic solvents. The ligand behaves as a bis-bidentall molecule coordinating through the phenolic oxygen and azomethine nitrogen atoms. The thermal decomposition of these metal complexes was investigated by thermogravimetric analysis and data have been analyzed for kinetic parameters using Broido equation. The solid-state electrical conductivity of the ligand and its polychelalls in the form of compressed pellet was studied in the temperaturc range from 313 to 413 K All the polychelalls were found to show semiconducting nature. The Mn（Ⅱ）, Fe（Ⅱ）, Co（Ⅱ） and Ni（Ⅱ） polychelalls have been assessed for the catalytic epoxidation of styrene.

Synthesis of cobalt single atom catalyst by a solid-state transformation strategy for direct C-C cross-coupling of primary and secondary alcohols

Atomic engineering of single atom catalysts(SACs)with high-density available active sites and optimized electronic properties can substantially boost catalytic efficacy.Herein,we report a solid-state transformation strategy to access Co SACs by introducing Co species from commercial CO_(2)O3 powders into nitrogen-doped carbon support.The catalyst exhibited excellent catalytic activity,with a turnover frequency(TOF)of 2,307 h^(-1)and yield of 95%,in the direct C-C cross-coupling of benzyl alcohol and 1-phenylethanol(1 atm O2@80℃)to yield chaicone.Density functional theory(DFT)calculations demonstrate the coordination environment and electronic metal-support interaction impact the catalytic pathway.In particular,a wide substrate scope and a broad functional-group tolerance of this SAC were validated,and the employment of this strategy for large-scale synthesis was also shown to be feasible.This work might shed light on the facile and scalable synthesis of highly active,selective,and stable SACs for heterogeneous catalysis.

环辛二烯氘代、开环易位聚合及其聚合物的固相催化加成

氘(氚)代聚合物是一类很有前景的惯性约束聚变靶材料.为制备具有较多加氚位点的氘代聚合物,开展了环辛二烯的氘代及开环易位聚合实验研究.对1,5-环辛二烯反应过程中间产物组分进行分析,研究了其氘代反应机理.通过核磁共振波谱(1H-NMR、2H-NMR、13C-NMR)分析,表明环辛二烯氘代后的副产物为氘代环辛烯.研究了温度、添加剂、反应时间对产物氘代率及副产物生成率的影响,获得了优化的反应条件,并制备了氘代率高达96%的氘代1,3-环辛二烯.开展了(氘代)1,3-环辛二烯的开环易位聚合实验,其中大量连续共轭双键的存在导致聚合物结晶使得其溶解性较差.在5 wt%的Pd/BaSO4与Grubbs二代催化剂的存在下,开展了聚1,3-环辛二烯、氘代1,3-环辛二烯与氘代环辛烯共聚物的固相催化加氘实验,均可加氘至接近饱和,在此过程中伴随着明显的氢同位素交换反应.发展了一种均相固相催化氢同位素加成的方法,有望实现在已成型的氘代聚合物靶丸上直接加氚,从而制备氘-氚代聚合物靶丸.