聚硅酸改性对活性氧化铝除氟性能的影响

采用聚硅酸对活性氧化铝进行改性,研究了SiO2百分含量、聚硅酸浸泡时间、焙烧温度及焙烧时间对改性活性氧化铝除氟性能的影响。结果表明,改性活性氧化铝能将水中的氟离子浓度从9.5 mg/L降低到0.89 mg/L,吸附容量提高了30%。因此,聚硅酸改性能有效提高活性氧化铝的除氟性能。     

无溶剂型双组分有机硅改性PU胶粘剂的制备与性能研究

以聚醚二元醇(DL-1000)、4,4′-二苯基甲烷二异氰酸酯(MDI)为主要原料合成端-NCO基PU(聚氨酯)预聚体;然后以γ-氨丙基三乙氧基硅烷(KH-550)对其进行嵌段共聚改性,并以3,3′-二氯-4,4′-二氨基二苯基甲烷(MOCA)/蓖麻油作为复合固化剂,制备出无溶剂型双组分有机硅改性PU胶粘剂。研究结果表明:硅烷键已引入PU胶粘剂中;随着KH-550含量的不断增加,胶粘剂的黏度增大、固化时间缩短、室温剪切强度下降且耐热性增强;通过调节不同KH-550含量,可制备出不同性能要求的胶粘剂;该胶粘剂的玻璃化转变温度(-45.9℃)相对较低,说明其耐寒性相对较好。     

微波辐射合成苯甲酸和苯甲醇的研究

采用微波密闭合成反应技术,对Cannizzaro反应进行了研究,研究了碱(NaOH)的质量分数、微波功率、辐射时间、反应温度对该反应的影响,通过测定苯甲酸熔点、苯甲醇的折光率检测产品纯度。结果表明:在微波辐射条件下,该反应速度快,比传统合成方法缩短反应时间数十倍,产率最高达85%,同常规方法相比有不同程度的提高。     

Homogeneous catalyzed reaction of carbon disulfide and o-phenylene diamine by tetrabutylammonium hydroxide in the presence of potassium hydroxide

The catalyzed reaction of o-phenylene diamine and carbon disulfide to synthesize 2-mercaptobenzimidazole (MBI) by tetrabutylammonium hydroxide (QOH; Q: (C₄H₉)₄N) was carried out in a homogeneous solution. A mixture of organic solvent (aprotic or protic) and water of an appropriate volume ratio acts as the homogeneous organic solution. The reaction is greatly enhanced either by tetrabutylammonium hydroxide or by tetrabutylammonium bromide in the presence of potassium hydroxide. Effects of the reaction conditions including the concentration of QOH, concentration of KOH, amount of CS₂, organic solvents, volume ratio of organic solvent to water, and temperature on the conversion of o-phenylene diamine are investigated in detail. An explanation is provided for the peculiar phenomena in studying the effects of the concentration of KOH on the conversion of o-phenylene diamine.     

Recent advantages in the metal (bulk and nano)-catalyzed S-arylation reactions of thiols with aryl halides in water: a perfect synergy for eco-compatible preparation of aromatic thioethers

Transition-metal-catalyzed C–S cross-coupling reactions comprise one of the most efficient methods for the synthesis of biologically and synthetically important aryl sulfide derivatives. Among the various solvents used in this cross-coupling reaction (ionic liquids, water, organic, and aqueous biphasic solvents), neat water have attracted notable interest in recent years due to its properties such as non-toxicity, non-flammability, renewability, and widely availability compared with other solvents. Since several catalytic systems for this green synthesis of aryl sulfides have been reported from 2007 to present, a comprehensive review on this interesting field seems to be timely. In this study, we discuss the most representative and interesting reports on the synthesis of aryl sulfides via metal-catalyzed cross-coupling of thiols with aryl halides in water. Mechanistic aspects of the reactions are considered and discussed in detail.     

含La2O3助催化剂的铁酞菁分子筛的微波合成及催化性能的研究

利用微波辐射法在KX分子筛内原位合成了以La2O3为助剂的铁酞菁,用IR、XRD对合成产物进行了表征,比较了加热方式对产率的影响。考察了产物对过氧化氢分解的催化活性。     

A new preparation approach for NiCoP/SiO2 catalyst by solid phase reaction of nickel and cobalt cations with potassium dihydrogen phosphate

A NiCoP/SiO₂ catalyst was fabricated by solid phase reaction of nickel chloride (NiCl₂) and cobalt chloride (CoCl₂) with potassium dihydrogen phosphate (KH₂PO₃). The structure and properties of NiCoP/SiO₂ were characterized by X-ray powder diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, thermal gravimetric analysis and Brunauer–Emmett–Teller in detail. A mechanism was postulated based on the results of thermal gravimetric analysis. The as-prepared NiCoP/SiO₂ catalyst had excellent hydrodesulfurization activity, as indicated by using dibenzothiophene as the reactant. Hydrodesulfurization occurred sequentially following hydrogenation of dibenzothiophene and desulfurization in the presence of NiCoP/SiO₂.     

Simultaneous removal of SO2 and NOx by microwave with potassium permanganate over zeolite

Simultaneous sulfur dioxide (SO₂) and nitrogen oxides (NO_x) removal from flue gas can be achieved with high efficiency by microwave with potassium permanganate (KMnO₄) over zeolite. The experimental results showed that the microwave reactor could be used to oxidation of SO₂ to sulfate with the best desulfurization efficiency of 96.8% and oxidize NO_x to nitrates with the best NO_x removal efficiency of 98.4%. Microwave accentuates catalytic oxidation treatment, and microwave addition can increase the SO₂ and NO_x removal efficiency by 7.2% and 12.2% separately. The addition of zeolite to microwave potassium permanganate increases from 16.5% to 43.5% the microwave removal efficiency for SO₂, and the NO_x removal efficiency from 85.6% to 98.2%. The additional use of potassium permanganate to the microwave zeolite leads to the enhancement of SO₂ removal efficiency up from 53.9% to 95%, and denitrification efficiency up from 85.6% to 98.2%. The optimal microwave power and empty bed residence time (EBRT) on simultaneous desulfurization and denitrification are 259 W and 0.357 s, respectively. SO₂ and NO_x were rapidly oxidized in microwave induced catalytic oxidation reaction using potassium permanganate with zeolite being the catalyst and microwave absorbent.     

Polyaniline supported CuI: An efficient catalyst for C–N bond formation by N-arylation of N(H)-heterocycles and benzyl amines with aryl halides and arylboronic acids, and aza-Michael reactions of amines with activated alkenes

Polyaniline supported CuI catalyst was prepared, characterized and effectively used in the N-arylation of N(H)-heterocycles and benzylamines with aryl halides and arylboronic acids and in aza-Michael reaction of amines with activated alkenes. The catalyst was recovered by simple filtration and reused for several cycles with consistent activity.