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。     

由钾明矾热分解法制备氧化铝和硫酸钾实验研究

采用重结晶方法对钾长石氟化学酸解法产物钾明矾进行提纯,通过焙烧-水浸等工艺制备硫酸钾和氧化铝。实验表明,较适宜工艺条件为:焙烧温度850℃、焙烧时间20 min、水浸温度100℃、水浸固液比1/5 g/m L、水浸时间20 min;氧化铝总收率86.52%,硫酸钾总收率85.02%;氧化铝纯度98.52%,符合GB/T 24487—2009氧化铝标准;硫酸钾中K2O质量分数为47.85%,符合GB 20406—2006农用硫酸钾标准。     

氟硅酸铵制备氟化钾联产白炭黑的实验研究

以磷肥副产的氟硅酸铵和氢氧化钾为原料,采用一步法制备氟化钾联产白炭黑。探讨主要因素对KF收率和KF纯度的影响,确定适宜的工艺条件为:反应温度82℃,w((NH_4)_2SiF_6)22%,w(KOH)40%,n(KOH)/n((NH_4)_2SiF_6)6.2;在配料比分别为6.2和6.1条件下,考查白炭黑洗涤水多次循环利用对氟化钾纯度、收率等的影响,综合考虑各项指标,最终确定配料比为6.2;在适宜工艺条件下产品各项指标均已达到HG/T 2829—2008、HG/T 3061—2009合格品的要求,且氟化钾产品收率可达94%以上。     

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。     

氟硅酸钾滴定法测定粗制氟化钠中二氧化硅

采用硝酸-氢氟酸混合酸为消解溶剂,通过微波消解技术对粗制氟化钠进行快速消解,并用氟硅酸钾滴定法测定其二氧化硅含量。选择饱和氯化钾溶液替代固体氯化钾作为沉淀剂,考察了消解酸体系、饱和氯化钾溶液用量、沉淀温度、沉淀放置时间、共存元素干扰及指示剂选择等条件对测定结果的影响并进行优化。确定了最优测试条件：以8 mL硝酸+2 mL氢氟酸为消解溶剂,以8 mL饱和氯化钾溶液为沉淀剂,控制沉淀温度为20~25 ℃、沉淀放置时间为15 min,选择50 g/L氯化钾-50%乙醇溶液洗涤沉淀,采用溴麝香草酚蓝-酚红指示剂。该方法应用于回收粗制氟化钠中二氧化硅含量的测定可大幅度缩短分解试样的时间,有效降低检测成本,回收率为99.15%~100.63%,相对标准偏差（RSD,n=8）小于1%,与传统高温碱熔法测定结果相符,方法的准确度和精密度较好。     

Optimized and functionalized paper sludge activated with potassium fluoride for single and binary adsorption of reactive dyes

The yield and adsorption uptake of optimized paper sludge activated carbon (PSAC) prepared using potassium fluoride as alternative chemical activation agent was investigated. The PSAC was functionalized with ethylenediamine (FPSAC) and both adsorbents were used for single and binary adsorption of Reactive orange 16 (RO16) and Reactive blue 19 (RB19). Effect of pH on the adsorption process, equilibrium, kinetics, isotherm and thermodynamic studies were carried out. Optimum PSAC preparation parameters were: activation temperature, X₁ = 810 °C; activation time, X₂ = 105 min; and impregnation ratio, X₃ = 0.95 which gave adsorption uptake of 178 and 158 mg/g for RO16 and RB19, respectively.     

高比表面积氟化镁的合成及其在催化中的应用研究进展

综述了氟化镁的合成、表征及在催化中的应用,指出了氟化镁在催化应用中的优缺点。氟化镁具有耐腐蚀性、高稳定性、表面性质可调等优点。目前主要应用的催化体系有：氟氯交换反应、氯氟烃的歧化反应、氯氟烃的加氢脱氯反应、加氢反应、加氢脱硫反应、氮氧化物的脱除等,在具有腐蚀性气体及反应介质的催化反应体系中具有独特的优势。缺点是氟化镁比表面积较小和表面酸性较弱,限制了其在催化研究中的应用。总结了高比表面积氟化镁及负载固体酸催化剂的制备方法及其在各类反应中的应用现状,重点阐述了高比表面积氟化镁的孔结构及其表面酸性的调控方法,最后指出了氟化镁催化剂在ODS替代物的合成领域及其它方面的发展前景。     

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。     

An efficient and environmentally friendly method for synthesis of arylmethylenemalononitrile catalyzed by Montmorillonite K10–ZnCl2 under ultrasound irradiation

Montmorillonite K10‐supported ZnCl₂ is an efficient and environmentally friendly catalyst. Knoevenagel condensation of malononitrile with aromatic aldehydes catalyzed by K10–ZnCl₂ in anhydrous ethanol produces arylmethylenemalononitriles in 87–98% yield within 2–10 min under ultrasound irradiation. The catalyst can be reused two times without significant decrease in activity. Copyright © 2004 Society of Chemical Industry     

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.     

有机溶剂浸取湿法磷酸脱氟渣制备磷酸的研究

脱氟渣是湿法磷酸化学沉淀脱氟过程产生的固体废渣。分别用甲醇、乙醇和丙酮浸取脱氟渣来回收脱氟渣中的磷酸,研究了浸取时间、温度和液固比对于五氧化二磷、氟的浸取率以及浸出液磷氟比［m（五氧化二磷）/m（氟）］的影响,得到了适宜的浸取条件。浸取液经蒸发浓缩回收浸取剂后,浓缩液均可满足饲料级磷酸氢钙生产对于湿法磷酸磷氟比的要求。综合考虑浸取剂成本、五氧化二磷浸取率和浸出液磷氟比,确定甲醇为优选浸取剂,并用响应面法对甲醇浸取工艺条件进行优化。优化工艺条件下五氧化二磷的浸取率为97.13%、浸出液磷氟比为51.62,甲醇在5次循环回收利用后对脱氟渣仍有较好的浸取效果。     

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.     

Surface layer of Pt-O-Ce bonds on CeOx nanowire with high ORR activity converted by proton beam irradiation

To develop the state-of-the-art polymer membrane fuel cells. Both maximization of oxygen reduction reaction (ORR) activity on Pt cathode and minimization of Pt content in the cathode are required. For this challenge, the defect interface on oxide support was modified by proton beam irradiation method. Pt-CeO_x nanowire/C (Pt/C = 0.02) was fabricated using the proton beam irradiation method. Since the radical density generated by proton beam irradiation is two orders of magnitude greater than that of electron beam irradiation, the CeO_x nanowire surface was fully converted to a thin layer of Pt-O-Ce bonds under proton beam irradiation. The ORR activity observed for fabricated sample with above active surface layer was higher than that of conventional Pt/C (Pt/C = 0.2) and comparable to that of Pt-CeO_x nanowire/C (Pt/C = 0.2) fabricated by conventional methods. From the combination of microanalysis characterization and surface atomistic simulation, we concluded that the Pt-O-Ce bond was formed on defect-rich regions of the CeO_x nanowire and this leads to a maximized ORR activity on the fabricated sample. Based on all experimental data, it is concluded that the surface modification of CeO_x nanowire support using proton beam irradiation is useful for a lowering the Pt content of the cathode with high ORR activity.     

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.