羰基合成高碳醇工艺研究进展

综述了对液/液两相催化高碳烯烃氢甲酰化制备高碳醇的研究进展,针对经典的水/有机两相体系不能用于催化高碳烯烃氢甲酰化的问题,全面介绍了适用于水/有机两相体系中高碳烯烃氢甲酰化的温控相转移催化法等6种改进方法。同时对氟两相、离子液体两相、超临界流体等非水液/液两相体系中的高碳烯烃氢甲酰化作了系统阐述,并对它们的应用前景进行了评价。     

烯烃氢甲酰化固载化催化剂研究进展

针对不同载体和固载化方法,综述了近年来固载化催化剂在烯烃氢甲酰化反应中的研究进展。重点介绍了以有机聚合物、分子筛、二氧化硅和活性炭等为载体的固载化催化剂的特点及其性能,并对各种固载化催化剂存在的问题和发展前景进行了分析。     

官能团化烯烃的氢甲酰化反应研究及应用进展

氢甲酰化反应已发展成为重要的工业均相催化反应之一,通过官能团化烯烃氢甲酰化反应可以得到官能团化的醛类化合物,该类化合物大多是精细化学品或合成中间体,官能团化烯烃显示出很多不一样的特性。综述近年来官能团化烯烃氢甲酰化反应研究进展,介绍乙烯基芳烃、α-官能团化烯烃以及β-官能团化烯烃的氢甲酰化反应及应用,并对官能团化烯烃氢甲酰化反应进行展望。     

Rhodium complexes supported on nanoporous activated carbon for selective hydroformylation of olefins

Activated carbon with nanoporous structure, high surface area (2500 m²/g) and total pore volume (2.35 cm³/g) was prepared from Mango seed shell (Mangifera indica L.) via chemical activation method and used as support to impregnate active hydroformylation rhodium complexes HRhCO(PPh₃)₃ and Rh(acac)(CO)₂. The prepared catalysts were characterized by XRD, SEM, TEM, NMR, IR, TGA, and N₂ adsorption/desorption techniques. The supported catalysts have shown excellent selectivity for aldehydes (~ 99%) in the hydroformylation of olefins with good stability and recyclability up to 4 cycles.     

Development of a continuous process for dissolving cellulose xanthate

Translated from Khimicheskie Volokna, No. 3, pp. 35–37, May–June, 1990.     

Cobalt catalyzed hydroformylation of higher olefins in the presence of chemically modified cyclodextrins

The cobalt catalyzed hydroformylation of higher olefins in the presence of chemically modified cyclodextrins was investigated in an aqueous biphasic system. The effect of various parameters, such as the nature of the cyclodextrin and olefin, the temperature, the CO/H₂ pressure, the concentration of the cyclodextrin and TPPTS was studied. The results demonstrate that the partially methylated β-cyclodextrin gives good conversion (>92%) and selectivity (>92%) for the hydroformylation of higher olefins without impeding the recovery of the catalytic system.     

Considerations on film reactivity in the aqueous biphasic hydroformylation

In experiments and kinetic models it was shown that the reaction rate of the biphasic aqueous hydroformylation of 1‐octene is linear dependent on the created interfacial area. This phenomenon is directly linked to the question whether the reaction takes place in the bulk phase and is mass transfer limitation or at the surface which would mean an increase of reaction space. To evaluate the place of reaction a mass transfer analysis has been carried out. No mass transfer limitation for the gaseous components carbon monoxide and hydrogen as well as the olefin 1‐octene was determined for the aqueous catalyst phase by calculating the Hatta numbers. With this observation it is possible to exclude the mass transfer as a potential influence and hence the aqueous bulk as the place of reaction. Thus the reaction is most probably surface active. This can be either explained the increase in film volume fraction where non‐polar substrate as well as polar catalyst complex is present or through an increased catalyst concentration at the surface through dipole moment fluctuations. © 2017 American Institute of Chemical Engineers AIChE J, 63: 161–171, 2018     

Development of a continuous dense gas process for the production of liposomes

A new process called Continuous Anti-Solvent (CAS) process was developed for the production of liposomes using supercritical CO₂. Unlike the current dense gas technologies, CAS method is a single step and continuous process. Preliminary experiments were conducted in semi-batch mode to determine the most suitable operating conditions (stirring speed = 225 rpm; water/lecithin mass ratio = 21) to ensure an efficient phase mixing in the autoclave. Then, two procedures were developed for the CAS process in the continuous mode. According to the results, the single exit procedure enhances the phase mixing in the autoclave with the formation of a CO₂-in-water emulsion which is a good precursor to liposome formation. Liposomes prepared with the CAS method (P = 9 MPa; T = 308 K; CO₂ flow rate = 0.3 kg h⁻¹; organic solution flow rate = 240 mL h⁻¹; water flow rate = 180 mL h⁻¹) are spherical and multilamellar with a medium diameter included between 10 and 100 μm.     

Development of a new continuous process for the production of 3,5-dimethylpiperidine

This paper developed a new clean continuous process for the hydrogenation of 3,5-dimethylpyridine(DPY) to 3,5-dimethylpiperidine(DPI) without solvent.A series of Ru/C catalysts were prepared by impregnation method,which were characterized by the BET,ICP,CO chemisorptions,XRD,SEM,EDS,TEM and TG.The effect of active species,loading,catalyst support,reaction temperature and pressure on the catalytic performance was investigated.The influence of internal and external diffusion in the trickle-bed rea...     

CFD数值模拟技术在液滴微流控多相流特性研究的应用进展

高集成化的微流控系统具有界面面积大、传递距离短、混合速度快等优势,已被广泛应用于许多科学领域。然而,微通道内多相流间的相互作用及动力学行为受多方面的影响,仅依靠试验观测技术和理论预测方法难以全面了解多相流传质传热过程、获取流场特性参数、揭示多相流相互作用规律。当下CFD数值模拟技术的快速发展为预测和分析微流控通道内的多相流问题提供了更为直观、有效、准确的帮助。本文对数值模拟技术在液滴微流控多相流特性研究的应用进展进行全面综述,涵盖液滴微流控装置结构及演变、液滴微流控模拟方法及优化以及微通道内多相流作用过程及原理。     

Aqueous biphasic hydroformylation of olefins: From classical phosphine-containing systems to emerging strategies based on water-soluble nonphosphine ligands

This review provides an overview of recent developments in the area of aqueous biphasic hydroformylation of higher olefins using metal catalysts and surfactants, cosolvents, thermoregulated ligands, cyclodextrins, and most importantly emerging water-soluble nonphosphine ligands. Water-soluble phosphine ligands have been widely explored for aqueous biphasic hydroformylation; however, phosphines are generally expensive and are prone to oxidation hence the recent interest in exploring other ligands. Various approaches have been used to introduce hydrophilicity to the ligands. The catalytic activity of monometallic and heterobimetallic systems containing nonphosphine ligands in aqueous biphasic media is emphasized in this review.     

Development of a continuous process for enol esters of fatty acids

A continuous process for the production of iso-propenyl stearate from stearic acid and propyne was developed. The reaction proceeds at elevated pres-sures and temperatures (∼550 psig and 400 F, respec-tively) in about l0 min. A slower, second reaction produces stearic anhydride from the isopropenyl stearate. A recovery section was devised, wherein the liquid product stream is chilled, recovered as flakes, and extracted with a solvent, e.g. Skelly B. Reaction studies were scaled-up from 10 to 40 lb feed/hr using triple pressed stearic acid and MAPP® gas (AIRCO, Inc., Montvale, NJ), a commercially available gas con-taining a nominal 1/3 propyne, 1/3 propadiene, and 1/3 stabilizing, saturated hydrocarbons. The acid and propyne are reacted in the presence of zinc stearate in a continuous stirred tank reactor (CSTR). The reac-tion is “finished” in a short tubular reactor. Data are presented on the effect of pressure, temperature, catalyst level, dwell in the reactors, and solvent ratio during extraction. The product is about 92% iso-propenyl ester, contaminated with unconverted stearic acid and by-product stearic anhydride.     

Removal of ciprofloxacin from aqueous solution by a continuous flow electro-coagulation process

This study deals with the performance and modeling of the electro-coagulation process for ciprofloxacin (CIP) removal by using aluminum electrode as anode in a continuous electrochemical reactor. The initial pH, temperature, current density, time and flow rate were selected as independent variables in response surface methodology (RSM) involving a five-level central composite design (CCD), while CIP removal efficiency was considered as the response function. The result of optimization showed that the maximum amount of CIP removal efficiency (88%) presented at the optimal condition of pH=5.6, t=100min, T=25.5 °C, I=5.6mA/cm² and V=25.9 mL/min. In addition, the mineralization of the CIP was investigated by chemical oxygen demand (COD) and total organic carbon (TOC) measurements that showed 77% COD removal and 49%TOC removal.     

A new chiral diphosphine ligand and its asymmetric induction in catalytic hydroformylation of olefins

A new chiral ligand, 1,6-anhydro-2,4-bis(diphenylphosphino)pyranose (ABDPP), was prepared from -glucose. The ligand was used to prepare a chiral rhodium catalyst system for asymmetric hydroformylation of olefins. For vinyl acetate, the catalytic hydroformylation gave rather high yield (96%), high enantioselectivity (92% ee), and high regioselectivity (b/n=95/5). But for styrene and norbornene, the results were not so good. The rather high sterioselectivity in the hydroformylation of vinyl acetate is explained in terms of the hydrogen bonding between OH group in the ligand molecule and the carbonyl group of vinyl acetate.     

Development of a technique for measuring the degree of dispersion of chrysotile fibre in aqueous systems

Chrysotile asbestos, when dispersed in an aqueous solution of a soap or a detergent by high shear mixing, results ultimately in a colloidal dispersion consisting of fibrils of approximately 30 nm in diameter and very high aspect ratio. In the intermediate stages of the dispersion process, slurries are produced which are represented by a wide range of colloidal concentrations and conversely a wide range of undispersed, macroscopic fibre concentrations. The degree of dispersion in these slurries and the dispersion mechanism cannot be assessed by existing methods of analysis. A new method capable of estimating the degree of fibre dispersion has been developed and has been termed Load Impulse Analysis. In the dispersion process, the disappearance of macroscopic fibres may be estimated and the development and destruction of a colloidal structure has been illustrated through this type of analysis. The meaning of the viscosity of a fibre dispersion measured at a low shear rate is also made clearer.     

Development of a pilot-plant process for the extraction of soy flakes with aqueous isopropyl alcohol

Soy flakes were extracted with aqueous isopropyl alcohol (IPA) at 77 C in a Kennedy countercurrent continuous extractor at a retention time of 71 min. IPA concentration was varied from 85.0 to 90.5% w/w and included the 87.7% IPA-water azeotrope. Solvent to meal ratios were varied from 1.5 to 3.0. The oil-IPA miscella leaving the extractor was chilled and coalesced to yield an oil phase and an IPA phase. The IPA phase was recycled to the extractor without being distilled. Excess IPA was expressed from the defatted flakes, and this also was recycled to the extractor. IPA recovered by distillation in the evaporator-stripper and desolventizer-toaster accounted for less than 10% of the total. Refined deodorized oils from the IPA extraction process compared favorably with their hexane counterpart in color, peroxide value and phosphorous and free fatty acid contents. Desolventized meals from the IPA process compared favorably with their hexane-extracted counterpart in protein, ash and fiber content.     

Modeling of the pervaporation process for isobutanol purification from aqueous solution using intelligent systems

In this study, intelligent systems (ANN-GA and GMDH) was employed to develope a model based on experimental data to predict the performance of the pervaporation process. The ANN system was coupled with the genetic algorithm (GA) to choose initial connection weights and biases of the multi-layer feed forward neural network (FFNN). The input parameters were the feed concentration, membrane thickness, and Reynolds number, while the outputs were total flux and permeate concentration. The RMSE of the estimated total flux for the ANN-GA and GMDH were 0.09170 and 0.0903, respectively. Also, the RMSE of estimated permeate concentration for the ANN-GA and GMDH were 0.0994 and 0.0975, respectively. The results indicated that the models had sufficient accuracy, but that GMDH could provide a better outcome. Finally, the relative importance of input variables on the network outputs was determined. Sensitive analysis showed that the membrane thickness and feed concentration are the most effect on the total flux and permeate concentration, respectively. Other variables also have important effect on the PV process and cannot be ignored.     

Model for a cascade continuous epoxidation process

A steady-state mathematical model was developed to analyze the performance of a cascade continuous epoxidation process that was applied to the epoxidation of unsaturated compounds with in-situ-formed performic acid. The model equations were nonlinear, and the model prediction was calculated by solving the model equations using a numerical solution procedure. The experimental results supported the model prediction in that good agreement between the model predictions and experimental results was achieved. The model is necessary for precise operation control, process estimation, and operating parameter optimization and regulation, and will provide a theoretical foundation and research method for automatic control and engineering scale-up.     

Use of ultrasound for phase holdup measurements in multiphase systems

This study evaluates ultrasound as a non‐invasive technique for determining the cross‐sectional holdups of multiphase systems. Experiments are performed in a column of 292 mm inner diameter with air, water and uniform glass beads of 1.3 mm diameter as the particles. In a bubble column, the signal intensity decayed exponentially with increasing gas holdup. In a liquid–solid fluidized bed, the wave time‐of‐flight decreased linearly when the solids holdup increased from 25% to 60% (fixed bed), while the signal intensity increased. Signal attenuation limits the use of this method for three‐phase fluidized beds. When large particles (mm range) are used, it is difficult to operate at a wavelength that permits transmission through both dispersed phases. For three‐phase systems, slurry bubble columns with low dispersed phases holdups and smaller particles present a less attenuative media and are better suited to this technique.     

Simulation and visualization of flow in a new miniature mixer for multiphase polymer systems

A newly designed mixer, the Alberta polymer asymmetric minimixer (APAM), was compared to the MiniMAX molder with flow simulation and flow visualization techniques to evaluate the performance of the mixers. The APAM has a unique, asymmetric design consisting of a varying clearance between the rotor blade tips and the cup wall, which enables the material to be squeezed, stretched, and kneaded in high‐shear and converging zones. Flow simulation showed that substantial folding and axial movement occurred in this mixer and that the pressure and velocity profiles exhibited high values at the rotor tip with the smallest rotor tip/cup clearance. In contrast, the MiniMAX molder had very simple flow patterns, which were insufficient to induce good dispersive and distributive mixing. These results concurred with those from an earlier work that studied the structure of blends and nanocomposites processed in the APAM compared to other polymer processing equipment. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 136–142, 2005