Preparation of Novel Membrane Material 4’,4’’(5’’)-di-tert-butyldicyclohexyl-18-crown-6

2014 ◽  
Vol 960-961 ◽  
pp. 73-77 ◽  
Author(s):  
Alsamani A. M. Salih ◽  
Ying Ming Li ◽  
Juan Fan ◽  
Chun Hai Yi ◽  
Bo Lun Yang
Keyword(s):  
Active Component ◽  
Catalyst Support ◽  
Cooperative Interaction ◽  
High Yield ◽  
Metal Catalyst ◽  
Reduction Temperature ◽  
Catalyst Structure ◽  
Reduction Time ◽  
Tert Butyl ◽  
20 Nm

For preparing 4’,4’’(5’’) di-tert-butyl-dicyclohexyl-18-crown-6 with high yield under low H2 pressure, the support, active component, promoter, reduction time and reduction temperature were studied. The catalyst structure and composition were characterized by XRD, TEM and EDS. The experimental results showed that MgO was the most suitable catalyst support because of its weaker acidity than other supports. The higher hydrogenation activity and selectivity were observed when Rh was used as the active component and Fe was used as promoter owing to the cooperative interaction. The optimum reduction temperature and the reduction time were 500 oC and 3h, respectively. The specific surface area of Rh-Fe/MgO was 133m2/g, and the Rh-Fe was well dispersed on MgO with the particle size about 20 nm. Under a low H2 pressure (4 MPa), the 4’,4’’(5’’) di-tert-butyldibenzo 18-crown-6 conversion was 78% and 4’,4’’(5’’) di-tert-butyl-dicyclohexyl-18-crown-6 yield was 53% catalyzed by Rh-Fe/MgO, which were higher than that catalyzed by single metal catalyst.

scholarly journals Effect of Coated Cow Dung on Fluidization Reduction of Fine Iron Ore particles

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1175
Author(s):  
Qiyan Xu ◽  
Zhanghan Gu ◽  
Ziwei Wan ◽  
Mingzhu Huangfu ◽  
Qingmin Meng ◽  
...  
Keyword(s):  
Iron Ore ◽  
Linear Velocity ◽  
Operating Conditions ◽  
Inhibition Mechanism ◽  
Cow Dung ◽  
Reduction Temperature ◽  
Reduction Time ◽  
Reducing Gas ◽  
Fine Iron ◽  
Ironmaking Process

The effects of reduction temperature, gas linear velocity, reduction pressure, reduction time, and reducing gas on the fluidized ironmaking process were studied for the fine iron Newman ore particles (0.154–0.178 mm) and the optimal experimental operating conditions were obtained. Under the optimal conditions, the effects of the coated cow dung on the reduction of fine iron ore particles were studied, and the inhibition mechanism of cow dung on particle adhesion in the fluidized ironmaking process was elucidated. The experimental results show that the optimal operating parameters are linear velocity of 0.6 m/s, reduction pressure of 0.2 MPa, reduction temperature of 1023 K, H2 as the reducing gas, and reduction time of 60 min. Cow dung can react with oxide in the ore powder to form a high melting point substance that can form a certain isolation layer, inhibit the growth of iron whiskers, and improve the fluidization.

Mechanical Behavior and Stress-Induced Martensitic Transformation in Nanocrystalline Ti49.4Ni50.6 Alloy

2008 ◽  
Vol 584-586 ◽  
pp. 470-474 ◽  
Author(s):  
Egor Prokofiev ◽  
Dmitriy Gunderov ◽  
Alexandr Lukyanov ◽  
Vladimir Pushin ◽  
Ruslan Valiev
Keyword(s):  
Grain Size ◽  
Tensile Strength ◽  
Martensitic Transformation ◽  
Ultimate Tensile Strength ◽  
High Pressure Torsion ◽  
Coarse Grained ◽  
High Yield ◽  
D 20 ◽  
20 Nm ◽  
High Ultimate Tensile Strength

Amorphous-nanocrystalline Ti49.4Ni50.6 alloy in the shape of a disc 20 mm in diameter has been successfully produced using high pressure torsion (HPT). Application of HPT and annealing at temperatures of 300–550°C resulted in formation of a nanocrystalline (NC) structure with the grain size (D) about 20–300 nm. The HPT samples after annealing at Т = 400°C with the D= 20 nm possess high yield stress and high ultimate tensile strength (more than 2000 MPa). There is an area of strain-induced transformation B2-B19’ on the tensile curve of the samples with the grain size D =20 nm. The stress of martensitic transformation (σm) of samples is 450 MPa, which is three times higher than σm in the initial coarse-grained state (σm ≈ 160 MPa). The HPT samples after annealing at Т = 550°C with the D= 300 nm possess high ductility (δ>60 %) and high ultimate tensile strength (about 1000 MPa).

scholarly journals Recovery of Iron, Chromium, and Nickel from Pickling Sludge Using Smelting Reduction

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 936 ◽  
Author(s):  
Zhaohui Tang ◽  
Xueyong Ding ◽  
Xinlin Yan ◽  
Yue Dong ◽  
Chenghong Liu
Keyword(s):  
Reduction Process ◽  
Slag Basicity ◽  
Experimental Results ◽  
Iron Ores ◽  
Reduction Temperature ◽  
Smelting Reduction ◽  
Reduction Time ◽  
Temperature Reduction ◽  
Pickling Sludge ◽  
Iron Chromium

This paper reports the recoveries of iron, chromium, and nickel from pickling sludge using coal-based smelting reduction. The influences of slag basicity (CaO/SiO2, which is controlled by high phosphorus oolitic hematite iron ores), reduction temperature, reduction time, and the C/O mole ratio on the recoveries of Fe, Cr, and Ni are investigated systematically. The experimental results show that high recoveries of Fe (98.91%), Cr (98.46%), and Ni (99.44%) are produced from pickling sludge with optimized parameters for the smelting reduction process. The optimized parameters are a slag basicity of 1.5; a reduction temperature of 1550 °C, a reduction time of 90 min, and a C/O mole ratio of 2.0. These parameters can be used as technical support for the recycling of pickling sludge with pyrometallurgy.

scholarly journals Applications of Modified Biochar-Based Materials for the Removal of Environment Pollutants: A Mini Review

2020 ◽  
Vol 12 (15) ◽  
pp. 6112 ◽  
Author(s):  
Jung Eun Lee ◽  
Young-Kwon Park
Keyword(s):  
Iron Oxides ◽  
Functional Groups ◽  
Advanced Oxidation Process ◽  
Catalyst Support ◽  
Environmental Pollutants ◽  
Metal Catalyst ◽  
Modified Biochar ◽  
Eutrophic Water ◽  
Iron Iron ◽  
Titanium Dioxides

The biochar treated through several processes can be modified and utilized as catalyst or catalyst support due to specific properties with various available functional groups on the surface. The functional groups attached to the biochar surface can initiate active radical species to play an important role, which lead to the destruction of contaminants as a catalyst and the removal of adsorbent by involving electron transfer or redox processes. Centering on the high potential to be developed in field applications, this paper reviews more feasible and sustainable biochar-based materials resulting in efficient removals of environmental pollutants as catalyst or support rather than describing them according to the technology category. This review addresses biochar-based materials for utilization as catalysts, metal catalyst supports of iron/iron oxides, and titanium dioxide because the advanced oxidation process using iron/iron oxides or titanium dioxides is more effective for the removal of contaminants. Biochar-based materials can be used for the removal of inorganic contaminants such as heavy meals and nitrate or phosphate to cause eutrophication of water. The biochar-based materials available for the remediation of eutrophic water by the release of N- or P-containing compounds is also reviewed.

scholarly journals Effect of Different Additives on Reaction Characteristics of Fluorapatite During Coal-Based Reduction of Iron Ore

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 923 ◽  
Author(s):  
Yongsheng Sun ◽  
Wentao Zhou ◽  
Yuexin Han ◽  
Yanjun Li
Keyword(s):  
Iron Ore ◽  
Contact Point ◽  
Energy Dispersive Spectrometer ◽  
Structural Evolution ◽  
Reduction Process ◽  
Reduction Degree ◽  
Reduction Temperature ◽  
Exponential Factor ◽  
Reduction Time ◽  
Effect Mechanism

In the coal-based reduction of high phosphorus oolitic hematite, it is particularly important to study the mechanism of phosphorus regulation during the formation of iron metals for the efficient development and utilization of iron ore. In this study, the thermodynamics of the coal-based reduction process of fluorapatite in different mineral systems, effect mechanism of the reduction degree, kinetics, mineral composition, and morphology of structural evolution samples were systematically investigated using FactSage software, single factor analysis, the isothermal method, X-ray diffraction (XRD), scanning electron microscope (SEM), and an energy dispersive spectrometer (EDS). Thermodynamic analysis indicates that the effect of the SiO2–Fe2O3–C system on reducing the initial reduction temperature of fluorapatite was stronger than that of the Al2O3–Fe2O3–C system. The effect mechanism of the reduction degree demonstrates that increasing the dosage of silica, iron oxide, carbon, reduction time, and reduction temperature could promote the reduction reaction of fluorapatite under certain conditions. Dynamics analysis shows that the best kinetic mechanism functions of the SiO2–Fe2O3–C system and the Al2O3–Fe2O3–C system were A1/3 = 1/3(1 − α)[−ln(1 − α)]−2 and A1/2 = 1/2(1 − α)[−ln(1 − α)]−1, respectively. The activation energy and pre-exponential factor of the reduction kinetics equation in the system containing silica were significantly lower than that in the system containing alumina, which explained that the catalytic effect of silica on the reduction of calcium fluorophosphate was far greater than that of alumina. XRD and SEM/EDS analysis indicate that the solid–solid reaction of alumina, silica, iron, and fluorapatite occurred during the reduction process, while calcium aluminate, calcium silicate, and calcium oxide were formed at the contact point. Among them, iron could absorb P2 gas so that it played a greater role in promoting the reduction of fluorapatite. Increasing the reduction temperature and prolonging the reduction time were beneficial to the reduction of fluorapatite.

Development of Efficient Metal Catalyst Support

2007 ◽  
Vol 561-565 ◽  
pp. 547-550 ◽  
Author(s):  
Shouichi Muraoka ◽  
Kazuhiro Kitamura ◽  
Satoshi Kishi ◽  
Tatuo Nakazawa ◽  
Yasuo Shimizu
Keyword(s):  
Aluminum Oxide ◽  
Oxide Layer ◽  
Catalyst Support ◽  
Wire Mesh ◽  
Metal Catalyst ◽  
Oxide Surface ◽  
Low Oxygen ◽  
Metallic Catalyst ◽  
Aluminum Oxide Layer ◽  
Aluminum Oxide Surface

A new wire mesh metallic catalyst support has been studied by using a stainless heat resistant steel of including aluminum. This catalyst support was improved for the metal honeycomb catalyst support that had been put to practical use. The wire mesh catalyst support was made in the following procedures. First, it was made from flat plate made by the stainless steel from the machining. Second, the low oxygen atmosphere in the heat treatment furnace did the aluminum extraction processing. Third, the aluminum oxide layer was made on the surface of catalyst support by furnace in air. Metal honeycomb catalyst has been made for several years by this method. The aim of this study was to evaluate the aluminum oxide layer on the surface of wire mesh catalyst support. The aluminum oxide surface was measured using scanning electron microscopy (SEM) and X-ray reflection diffraction (XRD). This catalyst support has the performance similar to the conventional metal honeycomb catalyst support.

Reactions of tert-Butyl Peroxy Esters, XIV. Further Observations on the Preparation of Dialkyl tert-Butylperoxy Phosphates

1975 ◽  
Vol 30 (9-10) ◽  
pp. 732-739 ◽  
Author(s):  
G. Sosnovsky ◽  
E. H. Zaret
Keyword(s):  
Potassium Hydroxide ◽  
Potassium Hydroxide Solution ◽  
Sodium Hydride ◽  
High Yield ◽  
Butyl Hydroperoxide ◽  
Tert Butyl ◽  
Tert Butyl Hydroperoxide ◽  
Aqueous Potassium Hydroxide ◽  
Butyl Peroxide

The preparation of dialkyl tert-butylperoxy phosphates (2, R = alkyl) has been achieved by the reaction of the corresponding dialkyl phosphorochloridates (1, R = alkyl) with tert-butyl hydroperoxide either in the presence of pyridine or in the presence of aqueous potassium hydroxide solution. Neither of these routes is suitable for the preparation of dialkyl tert-butylperoxy phosphates in quantity since they yield peroxyphosphates which are contaminated either with the corresponding tetraalkyl pyrophosphates or dialkyl phosphates; the contaminants cannot easily be removed by conventional means from the peroxyphosphates. The method of choice for the preparation in high yield of large quantities of pure dialkyl tert-butylperoxy phosphates involves the interaction of the corresponding dialkyl phosphorochloridate with sodium tert-butyl peroxide which has been prepared in situ from the reaction of tert-butyl hydroperoxide with sodium hydride.

scholarly journals Zeolites Catalyze the Nazarov Reaction and the tert-Butylation of Alcohols by Stabilization of Carboxonium Intermediates

Synthesis ◽  
2020 ◽  
Vol 52 (14) ◽  
pp. 2031-2037
Author(s):  
Antonio Leyva-Pérez ◽  
María Tejeda-Serrano ◽  
Sergio Sanz-Navarro ◽  
Finn Blake
Keyword(s):  
Organic Synthesis ◽  
Butyl Acetate ◽  
Strong Acid ◽  
Organic Reactions ◽  
High Yield ◽  
Acid Catalysts ◽  
Nazarov Cyclization ◽  
Triflic Acid ◽  
Nazarov Reaction ◽  
Tert Butyl

Zeolites are the most used catalysts worldwide in petrochemistry processes, with particular ability to stabilize carbocations. However, the use of zeolites in organic synthesis is still scarce. We show here that representative carboxonium-mediated organic reactions, such as the Nazarov cyclization and the tert-butylation of alcohols with tert-butyl acetate, typically performed with very strong acid catalysts in solution such as triflic acid, can be catalyzed by simple zeolites with high yield and selectivity. The aluminosilicate framework stabilizes the intermediate carboxonium species and overrides the need for superacid protons in solution.

Shadow Edge Lithography for Wafer-Scale Nanofabrication

2007 ◽  
Author(s):  
John Guofeng Bai ◽  
Jae-Hyun Chung
Keyword(s):  
High Vacuum ◽  
High Yield ◽  
Robust Method ◽  
Virtual Source ◽  
Ultraviolet Lithography ◽  
Wafer Scale ◽  
Shadow Effect ◽  
Etching Mask ◽  
Nanoscale Patterns ◽  
20 Nm

We propose shadow edge lithography (SEL) as a wafer-scale nanofabrication method. The shadow effect of “line-ofsight” in high-vacuum evaporation is analyzed theoretically to predict the geometric distributions of the fabricated nanoscale gaps. In the experiment, nanoscale gap patterns are created by the shadow of Al edges which are prepatterned using e-beam evaporation and the conventional ultraviolet lithography. Feasibility of the SEL is demonstrated by the fabrication of nanogaps having the width ranging from 15 to 100 nm on 4-inch Si wafers. Furthermore, by using the height differences in the prepatterned Al edges to compensate the geometric distributions of the shadow effect, it is demonstrated that the uniformity tolerance in the nanogap width can be ±1 nm or ±5% across the 4-inch Si wafers at a resolution down to 20 nm. The experimental results agree well with the theoretical prediction considering the virtual source during the e-beam evaporation. Upon the nanogap fabrication, arrays of nanochannels are obtained by reactive ion etching (RIE) using the evaporated Al layers as the etching mask. Our results show that that the evaporated Al layers can be used as the RIE mask to transfer the nanoscale patterns with a high yield and throughput. Thus, the SEL provides a robust method for wafer-scale fabrication especially for sub 50-nm structures.

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