Ammonium Metatungstate Hydrotalcite Catalyst
- Category: Ammonium Metatungstate
- Published on 30 September 2016
- Hits: 2216
In recent years, solid acid alkali catalysis of gas-solid-phase reaction of alkylation of catechols has attracted attention due to the environmentally friendly economy and overcoming the environmental pollution, separation and recovery difficulties and equipment corrosion and other defects, compared to conventional synthesis methods, and has shown significant advantages in saving resources and improving economic efficiency. It is found that Al-Ti-P-O, Al-Ti-Si-P-O and silica-supported ammonium metatungstate (AMT/SiO2) catalyst exhibited high catalytic activity.
Hydrotalcite is a kind of anionic clay with layered structure, because of its special layered structure and high catalytic performance in acid-base catalysis, condensation, addition polymerization, hydrogenation and alcohol conversion reaction, hydrotalcite has attracted many concerns. The exchangeable property of hydrotalcite anions make all kinds of anions (such as metatungstate ion) can be introduced into the interlayer of hydrotalcite in succession, thus to form a large class of materials - pillared hydrotalcite layered material.
A study has pointed out a preparation method of ammonium metatungstate hydrotalcite catalyst, and studied its catalytic performance, while the preparation steps are as follows:
1. synthesis of hydrotalcite material, take the raw material of magnesium nitrate hexahydrate, aluminum nitrate and sodium hydroxide, and to control the final pH value among 8 ~ 10 of the system, then go on aging, filtration and washing to get hydrotalcite NO3-MgAl;
2. Weigh a certain amount of fresh prepared hydrotalcite NO3-MgAl to disperse in distilled water, stirring at room temperature for overnight to fully expand;
3. Add dilute nitric acid dropwise to adjust the pH value of hydrotalcite slurry among 5.5~6, then rise the temperature to 348K;
4. Rapidly add ammonium metatungstate solution under the condition of stirring, and to react at 348K for 2 to 3 hours, then pumping wash the sample and dry at 348K to get the ammonium metatungstate hydrotalcite catalyst, i.e. AMT-Mg2Al.
The results showed that after changed with AMT, hydrotalcite will exhibit activity to the reaction of gas-solid phase reaction of catechol and methanol, while the conversion of catechol is 75%, the selectivity of guaiacol is 90%, but the catalytic activity decays.
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Ammonium Metatungstate Price on Sep.30th, 2016
- Category: Ammonium Metatungstate
- Published on 30 September 2016
- Hits: 1621
Ammonium metatungstate price with purity over 91.40% from Chinatungsten Online is 35.50 USD/KG, by Chinatungsten FOB Xiamen, Sep.30th, 2016.
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Ø1.6x150.0mm Cerium Tungsten Electrode Price on Sep. 29, 2016
- Category: Tungsten Electrodes Price
- Published on 29 September 2016
- Hits: 2386
WC10 Cerium tungsten electrode price with Ø1.6x150.0mm is 0.407USD/pc, EXW XIAMEN, CHINA, Sep. 29, 2016.
The MOQ for this diameter under such price is 5,000pcs.
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Ø500xØ460x400mm Tungsten Crucible Price on Sep. 29, 2016
- Category: Tungsten Metal Price
- Published on 29 September 2016
- Hits: 2034
Ø500xØ460x400mm tungsten crucible price with purity over 99.95% is 19,500.00USD/PC, EXW XIAMEN, CHINA, Sep. 29, 2016.
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Tungsten Crucible Price Ø500xØ460x400mm on Sep. 29, 2016
- Category: Tungsten & Sapphire Growth Furnace Price
- Published on 29 September 2016
- Hits: 1546
Sapphire growth furnace used tungsten crucible price Ø500xØ460x400mm with purity over 99.95% is 19,500.00 USD/PC, FOB XIAMEN, CHINA, Sep. 29, 2016
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Testing Trace Bismuth in High Purity Ammonium Metatungstate -- Co-Precipitation-HG-AFS Method
- Category: Ammonium Metatungstate
- Published on 28 September 2016
- Hits: 2144
Ammonium metatungstate (AMT) is an important intermediate compound of tungsten wet smelting process, with appearance of white and little yellow crystal. In recent years, as the requirement of tungsten product purity being higher and higher, for controlling and accurate detecting of impurity content in tungsten products, the required analysis of impurity element types gas been more and more. A study has put forward a method of co-precipitation-HG-AFS to testing trace bismuth in high purity ammonium metatungstate; HG-AFS refers to hydride generation atomic fluorescence spectrophotometry, which has shown to have advantages of high sensitivity, good selectivity and small matrix interference.
Steps of co-precipitation-HG-AFS method to detect trace bismuth in high purity ammonium metatungstate are as follows:
1. Weigh 0.125g (Accurate to 0001g) of high purity (99.995%) ammonium metatungstate sample in 50mL beaker, add a small amount of water, suitable amount of coprecipitation agent and KOH (The standard addition test requires adding standard solution in advance);
2. Carry out filtration after heated for 15min at low temperature, and wash the precipitation and the beaker twice by using KOH solution, again to wash twice with water;
3. Then goes on operation of coprecipitation twice, transfer to 25mL volumetric flask and add 5.0mL HCI, 2mL tartaric acid solution after the precipitation dissolved with hydrochloric acid solution (HCl), then diluted with water to scale, shake well to get mixture solution under test;
4. Test the ready solution by atomic fluorescence spectrometer;
5. Prepare series of different concentrations of bismuth standard solution, test the fluorescence intensity according to running program, and process data with computer, draw standard curve using monadic linear regression equation to calculate the content of bismuth.
The aim of choosing hydrochloric acid (HCl) as Current-carrying medium is to obtain bismuth fluorescence with high strength and stability, while, when the solution acidity is changing among 1~6mol/L, bismuth fluorescence value changed little, however the increasing acidity will help to eliminate the interference.
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2016.09.28-G25 Tungsten Carbide Polished Ball Ø15.875mm Price
- Category: Tungsten Carbide Price
- Published on 28 September 2016
- Hits: 1537
As reported by Chinatungsten Online, the current price of YG6 G25 tungsten carbide polished rod for Ø15.875mm is $5.10 per piece EXW Xiamen, China on Sep.28, 2016.
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2016.09.28-Tungsten Copper Electrode Ø6mmx150mm Price
- Category: Tungsten Copper Price
- Published on 28 September 2016
- Hits: 1469
As reported by Chinatungsten Online, the current price of 75%W25%Cu tungsten copper rod of Ø6mmx150mm is $4.50 per piece EXW Xiamen, China on Sep.28, 2016.
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2016.09.27- Tungsten Carbide Polished Rod Ø4.5mmx50mm Price
- Category: Tungsten Carbide Price
- Published on 27 September 2016
- Hits: 1520
As reported by Chinatungsten Online, the current price of YG10X tungsten carbide polished rod for Ø4.5mmx50mm is $1.00 per piece EXW Xiamen, China on SEP.27, 2016.
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2016.09.27-Tungsten Copper Plate 100mmx100mmx1.6mm Price
- Category: Tungsten Copper Price
- Published on 27 September 2016
- Hits: 1406
As reported by Chinatungsten Online, the current price of 90%W10%Cu tungsten copper plate of 100mmx100mmx1.6mm is $32.00 per piece EXW Xiamen, China on SEP.27, 2016.
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