2019年10月23日星期三

Monoalkyl Phosphate Preparation by Cesium Phosphotungstate

Monoalkyl phosphate is an important surfactant, widely used in chemical fiber, textile, leather, plastics, paper making and cosmetics. 

Monoalkyl phosphate usually synthesized by the esterification of phosphoric acid with aliphatic alcohols by esterification. The commonly used phosphorus agents are three oxychloride (POCl3) and phosphoric acid.

When phosphorus oxychloride is used as an agent for HCL, it is easy to cause environmental pollution, when phosphoric acid is used as a phosphate agent, although it is environmentally friendly, it is difficult to synthesize monoester, diester and three ester because of the low activity of phosphoric acid. Is there a way to improve the activity of phosphoric acid to help balance the benefits of the environment?

monoalkyl phosphate preparation image

Cesium phosphotungstate is a kind of heteropoly acid. It is a new type of multifunctional catalyst. It has not only oxidation reduction property, but also high catalytic activity and good stability, it can be used for homogeneous and heterogeneous reactions, and even can be used as phase transfer catalyst, the most important thing is that it is pollution-free to the environment. Some scholars have studied the synthesis of mono twelve alkyl phosphate by the direct esterification of lauryl alcohol and 85% phosphoric acid with cesium phosphotungstate as catalyst. Through investigation, we found that cesium phosphotungstate in the reaction process showed very high activity during the catalytic reaction, under the catalytic action of cesium phosphotungstate, the selectivity of MAP is 90% with the attraction between lauryl alcohol and phosphoric acid, a single twelve alkyl phosphate has been successfully synthesized. The effect is not weaker than three phosphorus oxychloride (POCl3). The most important is that it is safer and more environmentally friendly with phosphoric acid.

Over the years, cesium phosphotungstate has been recognized more and more by virtue of its excellent catalytic performance and non-toxic and harmless strength. So, when you're not satisfied with the catalytic effect of a certain chemical, you might be able to try cesium phosphotungstate.

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The PK Between Tungsten Trioxide and Titanium Dioxide Photocatalytic Performance

Photocatalysis is a photochemical reaction in the presence of a catalyst, it is a new science and technology.

Common photocatalysts include metal oxides (TiO2, ZnO, Fe2O3, Bi2O3, WO3) and metal sulfides (CdS, MoS2, MoSe2). Titanium dioxide TiO2 is the most white thing in the world, 1 grams of titanium dioxide can paint more than 450 square centimeter area to white. So it's the best paint for making white oil paint. The most well-known is that semiconductor photocatalysis performance of TiO2. TiO2 photocatalysis is widely used because of its high activity, photochemical stability, non-toxic and cheap.

Tungsten trioxide TiO2 is a kind of tungsten compounds that are widely used, It can be used not only for hard alloys, but also for dyes, the most commendable thing is that tungsten trioxide also with excellent photocatalytic performance. Like TiO2, WO3 also has high activity, photochemical stability, non-toxic and so on. If you compare the two, who can be better?

tungsten trioxide and titanium dioxide image

According to the data, TiO2 was the first compound to enter the field of photocatalysis, in 1972, the Japanese discovered that light irradiated TiO2 particles could cause water to undergo a sustained redox reaction, and began the history of photocatalysts. For a long time, TiO2 has been the preferred material for photocatalysis. Until 1983, the scholars in China used WO3 to treat printing and dyeing wastewater for the first time, and achieved very good results. Since then, WO3 has been discovered in application field and application, and gradually catch up from behind, outshining TiO2. How can WO3 compete with TiO2?

TiO2 was used as photocatalyst for a long time. But there are two fatal problems with the performance of TiO2, first, TiO2 has a narrow range of absorption of sunlight, which limits its use of solar energy. Second, photocatalytic reaction efficiency is low, generally not greater than 1%. With the increasingly serious problem of environmental water pollution, TiO2's capacity is too poor, TiO2's weaknesses are the strengths of WO3. From the performance point of view, the activity of WO3 photocatalytic degradation on organic pollutants is higher, the absorption and utilization on sunlight is better.

Tungsten trioxide has better chemical compatibility, WO3 can be mixed with ZnO, Bi2O3, rare earth La, Eu, Y and other elements to form a tungstate photocatalyst, not only pollution control, but also classify the printing and dyeing wastewater, antibiotic wastewater, metal wastewater targeted governance. Therefore, ignoring the price factor, the performance of WO3 undoubtedly has stronger competitiveness.

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Cesium Tungsten Bronze

Cesium tungsten bronze (CsxWO3) is synthesized by solid phase method or liquid phase method with cesium carbonate and sodium tungstate as raw materials.

Cesium tungsten bronze is also called cesium tungstate. CsxWO3 is a non stoichiometric functional compound with a special structure of oxygen eight surface, with low resistivity and low temperature superconducting properties. But in recent years, cesium tungsten bronze is popular for its excellent UV and near infrared shielding performance, with high efficiency, insulation and light reflection effect, this makes it good in the manufacture of special glass, high-end insulation film and LCD screen manufacturing.

In recent years, with the increasing popularity of cesium tungsten bronze, more and more scholars have begun to discuss the liquid phase preparation of cesium tungsten bronze. Some scholars have adopted the hydrothermal method to obtain cesium tungsten bronze, sodium tungstate and cesium carbonate were used as raw materials, in the citric acid solution, the CsxWO3 powder with six square Cs0.33WO3 structure was synthesized by hydrothermal method, and the CsxWO3powder was fully ground and dispersed in a citric acid solution, cesium tungsten bronze film was prepared on glass slide by dipping and dipping method. 

future house image

Through the test of cesium tungsten bronze film, we can draw a conclusion, the CsxWO3 powders obtained by hydrothermal method exhibit strong ultraviolet absorption and short wave near infrared absorption performance, moreover, the absorbance in short wave near infrared region increases with the prolonging of reaction time and the increase of citric acid content. The hydrothermal method failed to solve the cost problem more effectively, but the most important advantage of hydrothermal method is low carbon environmental protection, and the process is easier to control than solid phase method. If more details are to be improved, the large-scale application of cesium tungsten bronze will soon be possible. 

In recent years, with the improvement of people's living requirements, the concept of green house has been popular among people, in the near future, nanotechnology will seep into every detail of live, perhaps our walls, windows, doors, and floors can be made of special glass or paint or film to achieve automatic thermostat adjustment. There is no need to open air-conditioning in summer or open heating installation in winter, real energy saving and environmental protection are achieved, and at that time, such as cesium tungsten bronze and other new materials will certainly have unlimited room for development.

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【Know Tungsten】Sodium Tungstate Applications

Sodium tungstate, Na2WO4•2H2O, a tungstate of sodium, is useful as a source of tungsten. It is prepared from tungsten ores to manufacture tungsten by reducing it. It is often found as dihydrate.
sodium tungstate image
sodium tungstate image

If you have any inquiry of tungsten, please feel free to contact us:
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