甲乙酮装置的建设探讨

对甲乙酮原料及生产效益做了预测,着重讨论了建设甲乙酮装置应采用硫酸法的工艺路线,并对市场做了初步预测,对设备腐蚀问题也做了较为深刻的讨论。结果认为建设甲乙酮装置是有利可图的     

剩余丁烯脱水-精馏净化工艺在2500t/a甲乙酮装置的应用

介绍了在2 500t/a甲乙酮装置上外甩尾气中剩余丁烯经脱水-精馏净化工艺的回收利用。结果表明,经过脱水-精馏净化工艺的处理后,含水质量分数降至0.000 6%,完全脱除了剩余丁烯中的仲丁醇、仲丁醚和甲乙酮,满足甲乙酮装置的进料要求,可以循环利用。     

Low temperature complete combustion of dilute toluene and methyl ethyl ketone over Mn‐doped ZrO2 (cubic) catalysts

Combustion of dilute toluene and methyl ethyl ketone over Mn‐doped ZrO₂ catalysts prepared using different precipitating agents, such as tetra‐alkyl ammonium hydroxides and NH₄OH, having Mn/Zr ratios from 0.05 to 0.67, and calcined at different temperatures has been thoroughly investigated. The Mn‐doped ZrO₂ catalyst shows high toluene or methyl ethyl ketone combustion activity, particularly when its ZrO₂ is in cubic form, when its Mn/Zr ratio is close to 0.2, and when it is prepared using tetra‐methyl ammonium hydroxide as a precipitating agent and calcined at 773 K. Copyright © 2005 Society of Chemical Industry     

二(N-吲哚基)乙二酮的合成研究

以吲哚与草酰氯为原料,经取代反应得一种新物质,二(N-吲哚基)乙二酮,经IR谱确认其结构。     

La–Ag–Co perovskites for the catalytic flameless combustion of methane

Ag represents an interesting dopant for the highly active LaCoO₃ perovskites used for the catalytic flameless combustion (CFC) of methane, due to its ability to adsorb and activate oxygen and to the possibility of incorporation into the framework as Ag⁺ or Ag²⁺, with formation of oxygen vacancies. In the present work we compared the catalytic activity and resistance to sulphur poisoning of a series of LaCoO₃, x%Ag/LaCoO₃, La_1−xAg_xCoO₃ samples (nominal composition), the latter two notations indicating post-synthesis Ag loading or direct incorporation during the synthesis, respectively. The samples were prepared by flame pyrolysis (FP) and by the sol–gel (SG) method, leading to different particle size and possibly to different incorporation degree of the dopant, quantified by Rietveld refinement of XRD patterns.Higher activity was observed, in general, with fresh catalysts synthesised by FP. The SG samples demonstrated a slightly better resistance to sulphur poisoning when considering the conversion decrease between the fresh and the poisoned samples, due to lower surface exposure. However, interesting data have been obtained with some of the Ag-doped poisoned FP samples, performing even better than the fresh SG-prepared ones.Ag addition led to a complex change of activity and resistance to poisoning. The activity of FP-prepared samples doped with a small amount of Ag (e.g. 5 mol%) was indeed lower than that of the undoped LaCoO₃. By contrast, a further increase of Ag concentration led to increasing catalytic activity, mainly when big extraframework Ag particles were present. By contrast, for SG samples a low Ag amount was beneficial for activity, due to an increased reducibility of Co³⁺.     

Synthesis of (Ni,Mn,Co)O4 nanopowder with single cubic spinel phase via combustion method

(Ni,Mn,Co)O₄ nanopowders with single cubic phase were successfully synthesized using combustion methods. Particle size of the as-burnt nanopowders after combustion was about 20 nm. Crystallization behavior of the NMC was investigated using various techniques such as X-ray diffraction (XRD), thermogravimetric (TG), Fourier transform infrared (FT-IR) spectroscopy, and transmission electron microscopy (TEM). Calcination at different temperature from 400 °C to 700 °C provides the powders with increased crystallinity and grain size. However, further increasing temperature above 800 °C for calcination, cubic spinel phase of NMC partly transformed to tetragonal spinel phase, which implies that cubic spinel phase of NMC nanopowder synthesized by combustion method becomes unstable above 800 °C.     

丁酮肟-丁酮、正己烷、环己烷二元体系密度和黏度的测定及关联

丁酮肟由于其低毒、低污染和高脱氧效果而被用作防结皮剂、锅炉的除氧剂和脱酮肟基硅烷交联剂的生产原料,然而丁酮肟及其二元混合体系的密度与黏度却鲜有报道。本文利用密度瓶,测定了丁酮肟-丁酮、丁酮肟-环己烷和丁酮肟-正己烷三个二元体系在(293.15～303.15)K、常压条件下的密度,用乌氏黏度计测定了三个二元混合体系在(293.15～303.15)K、常压条件下的黏度。对不同温度下混合密度与组成的关系,通过多项式方程进行了拟合;对不同温度下混合黏度与组成的关系,分别通过Grunberg-Nissan和Eyring-UNIQUAC方程进行了拟合,并给出了回归系数和平均相对偏差。本文数据和关联可为丁酮肟相关工业过程的设计、模拟和优化提供便利。     

TiO2 coating types influencing the role of water vapor on the photocatalytic oxidation of methyl ethyl ketone in the gas phase

Four TiO₂-based materials, named A, B, C and D, are used to investigate the influence of water vapor on the gas–solid adsorption and heterogeneous photocatalytic oxidation of gaseous methyl ethyl ketone (MEK). Two of the photocatalysts (A and B) are constituted of powdered TiO₂ deposited onto two different supports (ordinary glass and non-woven cellulose fibers). The other ones (C and D) are composed of a thin film of TiO₂ coated on glass substrates. The effect of water vapor on MEK initial conversion rates is studied for the four photocatalytic materials using the Langmuir–Hinshelwood model at the initial time. On the concentrations range where the model hypotheses are verified, adsorption constants K and kinetics constants k are calculated for experiments under both dry and humid atmosphere. When the relative humidity is increased, the evolution of these constants shows that water vapor acts differently depending on the form of deposited TiO₂ (powder and film).     

Oxidation of alkylaromatics to benzylic ketones using TBHP as an oxidant over LaMO3 (M = Cr,Co, Fe,Mn, Ni) perovskites

A series of LaMO₃ (M = Cr, Co, Fe, Mn, Ni) perovskites were synthesized by citrate precursor decomposition method and characterized by XRD technique. The catalytic activity of the synthesized perovskites was investigated for the oxidative functionalization of alkylaromatics to benzylic ketones using TBHP as an oxidant. Of various perovskites screened, LaCrO₃ exhibited remarkable catalytic activity providing the oxidation of alkylarenes selectively at the benzylic position. The LaCrO₃/TBHP catalytic system provides excellent yields of the desired ketones under solvent-free conditions and the catalyst can be successfully used up to six consecutive cycles with no significant loss in activity.     

Magnetic properties of Er(Co,Mn)O3 perovskites

The erbium-based manganite ErMnO₃ has been partially substituted at the manganese site by Co in the general formula ErCo_xMn_1−xO₃. The perovskite orthorhombic structure is found from x(Co) = 0.3 up to x(Co) = 0.7, provided that the synthesis is performed under oxygenation conditions to favour the presence of Co³⁺. Magnetic properties show unusual phenomena, correlated with the presence of different magnetic entities (i.e., Er³⁺, Co²⁺, Co³⁺, Mn³⁺, Mn⁴⁺): the overall magnetic moment reverses its sign when the sample is cooled under an external magnetic field, while the magnetization loops performed at T < 4 K show intersecting branches at low fields and a sudden jump at high fields. A phenomenological model of two interacting sublattices, coupled by an antiferromagnetic exchange interaction, explains the inversion of the overall spin, while the high-field discontinuity is explained in terms of dynamical models.     

Oxidation of alkylaromatics to benzylic ketones using TBHP as an oxidant over LaMO3 (M = Cr, Co, Fe, Mn, Ni) perovskites

A series of LaMO₃ (M = Cr, Co, Fe, Mn, Ni) perovskites were synthesized by citrate precursor decomposition method and characterized by XRD technique. The catalytic activity of the synthesized perovskites was investigated for the oxidative functionalization of alkylaromatics to benzylic ketones using TBHP as an oxidant. Of various perovskites screened, LaCrO₃ exhibited remarkable catalytic activity providing the oxidation of alkylarenes selectively at the benzylic position. The LaCrO₃/TBHP catalytic system provides excellent yields of the desired ketones under solvent-free conditions and the catalyst can be successfully used up to six consecutive cycles with no significant loss in activity.     

聚芳醚酮/含甲基侧基聚芳醚砜醚酮酮的合成与表征

以2，2’-二甲基-4,4'-二苯氧基二苯砜(o-CH3-DPODPS)、二苯醚(DPE)和对苯二甲酰氯(TPC)为单体，在无水A1C13、1，2-二氯乙烷和N，N-二甲基甲酰胺存在下，通过低温溶液缩聚反应。合成了一系列新型含甲基侧基的聚芳醚酮／聚芳醚砜无规共聚物。用FT-IR，WAXD，DSC和TG等方法对聚合物进行了表征。结果表明，随着2,2'-二甲基-4，4'-二苯氧基二苯砜含量的增加，共聚物的玻璃化转变温度逐渐提高，熔融温度则逐渐下降。     

Selective Hydrogenation of Cinnamaldehyde over Pt/ZrO2 Catalyst Modified by Cr, Mn, Fe, Co and Ni

Hydrogenation properties of cinnamaldehyde (CMA) have been studied over Pt/ZrO₂ and PtM/ZrO₂ catalysts (M = Cr, Mn, Fe, Co and Ni) in ethanol at 343 K and 2.0 MPa. The effect of different content of Ni and base has also been investigated over PtNi/ZrO₂ catalyst. With introduction of transition metals to Pt/ZrO₂ catalyst shows a significant influence on the catalytic properties. PtCo/ZrO₂ catalysts show the best yield of cinnamyl alcohol (CMO), and PtNi/ZrO₂ catalyst shows good yield of hydrocinnamaldehyde (HCMA). In the presence of base solution, rate of the hydrogenation of CMA over PtNi/ZrO₂(0.4 wt%) catalyst increases significantly and side reaction is remarkably inhibited. More bare metal atoms situated remote from the interface region on PtNi/ZrO₂ catalyst surface are the reason of good selectivity of HCMA for PtNi/ZrO₂ catalyst.     

Solution combustion synthesis of (Co,Ni)Cr2O4 pigments: Influence of initial solution concentration

Initial solution concentration effect was studied on the synthesis of mixed spinels Co_1-ΨNi_ΨCr₂O₄ (0≤Ψ≤1) obtained by Solution Combustion Synthesis. Fd-3m spinel structure was developed in all range of compositions analysed, regardless of the concentration. However, structural characteristics such as ion rearrangement and crystal size showed a noticeable dependence on the initial concentration, being the spinel network more ordered and with higher crystallite size as the concentration increased. Cell parameter, however, presented dependence on composition but not on initial solution concentration.All as-synthesized pigments showed a significant colouring power in ceramic glazes without any significant influence of initial solution concentration. Therefore, a second thermal treatment was not needed. The coloured glazes covered a broad range of tones in the green section of colour space, which evolved as a function of composition.     

Measurements and correlation of liquid–liquid equilibrium data for the ternary(methyl tert-butyl ketone + o,m, p-benzenediol + water)system at(333.2, 343.2 and 353.2) K

In this work, liquid–liquid equilibria(LLE) data for the ternary system methyl tert-butyl ketone(MTBK) + o, m,p-benzenediol + water were investigated at 333.2 K, 343.2 K and 353.2 K under 101.3 kPa. The performance of MTBK to extract o, m, p-benzenediol from wastewaters was estimated by partition coefficients and separation factors. The Hand and Bachman equations were both applied to check the reliability of the experimental LLE data. Furthermore, the Non-Random Two-Liquid(NRTL) and Universal Quasi Chemical(UNIQUAC) models were applied to correlate the measured LLE data. The results showed a good agreement with the determined ternary LLE data with the root-mean-square error(RMSE) values below 0.71%. MTBK was proved to be a promising extracting agent in extracting benzenediols from effluents.     

Facile synthesis of magnetic metal (Mn, Fe, Co, and Ni) oxides nanocrystals via a cation-exchange reaction

Magnetic metal (Mn, Fe, Co, and Ni) oxides nanocrystals with small size and uniform size distribution are synthesized via a cation-exchange reaction. Two experimental stages are included in the synthesis of metal oxides nanocrystals. Firstly, Cu(OH)2 decomposes to CuO nanocrystals, induced by free metal cations. Compared to CuO nanocrystals produced without any free metal cation, the free metal cation has an important influence on the shape and size of CuO. Secondly, free metal cations exchange with the Cu2+ cation in the CuO nanocrystals to get Mn3O4, Fe2O3, CoO and NiO nanocrystals by cation-exchange reactions. The magnetic properties of these metal oxides nanocrystals have been investigated, all the nanocrystals are superparamagnetic at room temperature.     

Physicochemical properties of rock salt-type ordered Sr2MMoO6 (M = Mg,Mn, Fe,Co, Ni) double perovskites

B-site rock salt-type ordered Sr₂MMoO₆ (M = Mg, Mn, Fe, Co, Ni) oxides have been systematically investigated in terms of their crystal structure, oxygen non-stoichiometry, transport properties, thermal expansion and chemical stability. Structural evolution on temperature of the studied materials was interpreted on a basis of octahedra rotation, with I4/m → Fm-3m phase transition. In the case of P2₁/n → I4/m transformation recorded for Sr₂MnMoO₆, a region of coexistence of two phases was observed. The Fe-containing compound was found to possess very high electrical conductivity, around 1000 S cm⁻¹ in 5 vol.% H₂ in Ar, and small negative Seebeck coefficient. Studies show that Mn- and Fe-containing compounds are stable only in reducing conditions, Co- and Ni-containing ones are stable only in oxidizing conditions, while Sr₂MgMoO₆ remains stable in a wide range of oxygen partial pressures. Recorded power density of a button-type SOFC with Sr₂FeMoO₆-based anode was 0.32 W cm⁻² at 900 °C.     

Preparation and Properties of Ethylene Vinyl Acetate (EVA)/Organoclay/Compatibilizer Nanocomposites: Effects of Organoclay Loading and Methyl Ethyl Ketone

Ethylene vinyl acetate (EVA)/organoclay/compatibilizer nanocomposites were produced using a melt compounding technique in an internal mixer, Haake Rheometer, at 120°C and 50 rpm rotor speed. Effects of organoclay loading (from 2 to 10 phr—parts per hundred of resin and methyl ethyl ketone (MEK), used as a compatibilizer, on the processing properties, tensile properties, morphology, thermal degradation, and water absorption behavior of EVA/organoclay nanocomposites were studied. Results indicate that the presence of organoclay increase the processing torque, tensile properties, thermal degradation, and resistance to water absorption. The optimum organoclay loading was achieved at 2 phr. This was caused by the dispersion state of individual silicate layers (intercalation/exfoliation) in EVA matrix. The intercalation/exfoliation structure affects the properties of EVA/organoclay nanocomposites as evidenced from the morphology studies such as x-ray diffraction (XRD) and transmission electron microscopy (TEM) evaluation. The addition of MEK has the ability to improve the tensile properties, thermal degradation, and slightly reduces the resistance of water permeation of EVA/organoclay nanocomposites. The enhanced properties were seen as a result of the better matrix and filler interaction. The EVA/organoclay/MEK nanocomposites shows better intercalation/exfoliation of individual silicate layers in the EVA matrix as indicated by TEM. Moreover, the XRD evaluation shows that intercalation/exfoliation of the organoclay was formed in the EVA matrix.     

Effects of composition and furnace temperature on (Ni,Co) (Cr,Al)2O4 pigments synthesized by solution combustion route

The effects of composition and furnace temperature on Ni_1‐ΨCo_ΨCr_2?2ΨAl_2ΨO₄ (0≤Ψ≤1) pigments prepared by Solution Combustion Synthesis were studied. As‐synthesized samples showed spinel‐like spongy structure, very easy to grind. However, important differences on crystallinity, crystal size, and microstructure were observed depending on composition and furnace temperature. All pigments developed intense tones, covering a wide color palette because of composition influence, although little effect was observed with furnace temperature. Stable crystalline structures, suitable grain size, and high resistance against synthesizing variables and ceramic glazes make SCS pigments perfect candidates to be used in the ceramic ink‐jet decoration.