AMT/SiO2 Catalyst on Orthortho-Hydroxy Anisole Production II

Ammonium metatungstate, also known as AMT, is a tungsten chemical in the form of highly soluble hydrated crystals. Global Tungsten & Powders AMT is produced as minus 10-mesh powder to meet stringent demands in the catalyst, medical, semiconductor and other high-technology industries. GTP AMT is also used in materials research and in analytical chemistry. At room temperature, aqueous solutions can be saturated up to 70% by weight of contained WO3. This equates to 1.6 kilograms per liter or 13.3 pounds per gallon.

AMT / SiO2 catalyst calcined at different temperatures has different degrees of AMT decomposition, resulting in different properties of the catalyst surface pH center, resulting in catalyst performance vary. The activity and stability of catalyst prepared at low firing temperature calcination is much better than a catalyst prepared at high firing temperature. Weak acid-weak alkali centers on the catalyst surface is the main activity center of catechol and methanol monoetherification reaction to produce ortho-hydroxy anisoles. the main reason for the reduced activity is coke on the catalyst surface during the reaction. the catalyst after inactivation was calcined at a higher temperature and regeneration treatment then the reactivity partially restored, but still significantly lower than the fresh catalyst, and the stability of the catalyst after regeneration process is poor. This may be the high temperature regeneration properties of the active center of the catalyst surface (including pH properties) has changed, so that the regenerated catalyst is more easily inactivated.

AMT/SiO2 Catalyst on Orthortho-Hydroxy Anisole Production I

Orthortho-hydroxy anisole is important fine chemical intermediates and chemical raw materials, with a wide range of applications. Pyrocatechol - Methanol Gas phase single etherification method to produce orthortho-hydroxy anisole has attracted much attention due to its advantages of economic and environmental, some effective catalyst systems of this reaction have been found including a variety of complex oxides, phosphates and zeolite.

According to preliminary studies on phosphates and phosphate multicomponent catalyst, it’s found that a weak acid - weak alkali catalyst usually shows high activity and selectivity on the reaction of pyrocatechol and methanol vapor phase synthesis of orthortho-hydroxy anisole. Recently, scholars have found that supported ammonium metatungstate (AMT) catalyst prepared by SiO2, TiO2, and Al2O3 as the carrier has good catalytic performance on this reaction. In which the tungsten loading of 7.9% of AMT / SiO2 catalyst has the best performance. Preliminary characterization results show that the weak acid - weak alkali species formed by ammonium metatungstate partial decomposition are the the active center of the catalytic reaction in roasting preparation processing. On this basis, the study focused on the influence of calcination temperature on pyrocatechol and methanol vapor single etherification performance with AMT / SiO2 catalyst and examine the stability and performance of the catalyst regeneration. Meanwhile, according to X-ray diffraction (XDR), infrared spectroscopy (IR), temperature programmed desorption (TPD), scanning electron microscopy (SEM) and differential thermal - thermogravimetric (TG-DTA), catalyst structure, surface acidity the nature and reasons for deactivation were discussed.

Morphology and Size of Ammonium Metatungstate Microsphere Prepared by Spray Drying Method

Ammonium metatungstate (AMT) is usually used as one of the precursors of tungsten carbide (WC) catalyst, and the properties of AMT precursor affect the morphology and size distribution of WC microsphere, which have a finally effect on the catalyst activity.

In this work, the mechanisms of airflow and centrifugal spray drying methods were introduced, then the AMT microspheres having different morphologies were prepared by using these two kinds of spray drying methods, and the morphology and size of the microspheres prepared were studied. The results show that the morphology of the powder prepared by centrifugal spray drying is solid sphere, and it is different from that of the powder prepared by airflow spray drying, which is hollow sphere. For the airflow spray drying method used, the effects of solution concentration, feed rate and surfactant on the particle size of products were investigated.

It was found that the solution concentration is the most important factor affecting the particle size, and under different drying conditions, the minimum median diameter (d50) of the dry products is 2.26 μm. This study might provide a referential foundation for the morphology and size control of hollow global WC microspheres prepared by the gas-solid reaction method of spray drying sphere miniaturization.

Ammonium Metatungstate(AMT) Industry China Market Research Report 2016

The China Ammonium Metatungstate(AMT) Industry 2016 Market Research Report is a professional and in-depth study on the current state of the Ammonium Metatungstate(AMT) industry.

The report provides a basic overview of the industry including definitions, classifications, applications and industry chain structure. The Ammonium Metatungstate(AMT) market analysis is provided for the China markets including development trends, competitive landscape analysis, and key regions development status.

Development policies and plans are discussed as well as manufacturing processes and Bill of Materials cost structures are also analyzed. This report also states import/export consumption, supply and demand Figures, cost, price, revenue and gross margins.

The report focuses on China major leading industry players providing information such as company profiles, product picture and specification, capacity, production, price, cost, revenue and contact information. Upstream raw materials and equipment and downstream demand analysis is also carried out. The Ammonium Metatungstate(AMT) industry development trends and marketing channels are analyzed. Finally the feasibility of new investment projects are assessed and overall research conclusions offered.

With 148 tables and figures the report provides key statistics on the state of the industry and is a valuable source of guidance and direction for companies and individuals interested in the market.

Structure and Thermal Decomposition of Ammonium Metatungstate

Ammonium metatungstate, also known as AMT, is a tungsten chemical in the form of highly soluble hydrated crystals. Global Tungsten & Powders AMT is produced as minus 10-mesh powder to meet stringent demands in the catalyst, medical, semiconductor and other high-technology industries. GTP AMT is also used in materials research and in analytical chemistry. At room temperature, aqueous solutions can be saturated up to 70% by weight of contained WO3. This equates to 1.6 kilograms per liter or 13.3 pounds per gallon.

The structure and morphology of ammonium metatungstate (AMT), (NH4)6[H2W12O40]⋅4H2O, and its thermal decomposition in air and nitrogen atmospheres were investigated by SEM, FTIR, XRD, and TG/DTA-MS. The cell parameters of the AMT sample were determined and refined with a full profile fit. The thermal decomposition of AMT involved several steps in inert atmosphere: (i) release of crystal water between 25 and 200 °C resulting in dehydrated AMT, (ii) formation of an amorphous phase between 200 and 380 °C, (iii) from which hexagonal WO3 formed between 380 and 500 °C, and (iv) which then transformed into the more stable m-WO3 between 500 and 600 °C. As a difference in air, the as-formed NH3 ignited with an exothermic heat effect, and nitrous oxides formed as combustion products. The thermal behavior of AMT was similar to ammonium paratungstate (APT), (NH4)10[H2W12O42]⋅4H2O, the only main difference being the lack of dry NH3 evolution between 170 and 240 °C in the case of AMT.

Synthesis and Interfacial Electron Transfer of a Composite Film of Graphene and AMT

Solar energy is a renewable energy, hydrogen production with that is expected to solve the current common problems of energy shortage and environmental pollution, which has been widespread concerned. In many semiconductor photocatalytic hydrogen production materials, tungsten oxide become a hot research materials in the photocatalytic field due to its stable performance and low cost, but its optical electronic - holes are so easy to combine that restrict the photoelectric device performance. In order to improve the photoelectric conversion performance of the tungsten oxide, the domestic and international researchers carried out a number of explorations. Currently, common methods are semiconductor compound, noble metal deposition, surface sensitization, ion doping.

With ammonium metatungstate as tungsten source, PVP as binding agents, use dip-coating method to prepare graphene - tungsten oxide composite films, using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy methods such as composite structure were characterized by light and current test, electrochemical impedance spectroscopy (EIS), transient photocurrent spectrum and intensity modulated photocurrent spectroscopy methods to study complex film electrode interface at a photoelectric effect carriers transfer process and a charge transport behavior. The results show that the composition of the film and the tungsten oxide nanoparticles are graphene fully complex, significantly improved photoelectric properties; graphene composite after the transient time constant of the film is increased, the electron - hole pairs life expectancy; electron transport time is reduced, as 47.5% of pure tungsten oxide film.