Partial oxidation of natural gas for preparing synthesis gas is an important intermediate link for realizing the transformation of natural gas, while the researching and development of efficient catalyst is the key. As the main component of natural gas, the new synthetic route of methane as alternative energy for manufacturing high value-added liquid chemicals and other organic chemical is attached great concerns all around the world. 

Because of spherical tungsten carbide powder (WC) has the properties of high hardness, wear resisting and chemical property and acid and alkali resistant, it has widely potential application value in the fields of fuel cell anode, cathode catalyst material, gas sensor, petroleum catalyst, photocatalyst material. 

Tungsten oxide (WO₃) with low dimensional nanostructure is a kind of important functional material, especially the WO₃ nanometer single crystal. Since it has good gas sensitive, light corrosion resistance, electrochromism, gasochromism, thermochromism and photochromism and other properties, it is widely used in gas sensor, visible light catalyst, flat-panel display, and other fields. The raw materials of tungsten trioxide nanometer single crystal are soluble tungstate, WO₃ceramics material, metal tungsten and tungsten hexachloride, with the manufacturing method of ion exchange, hydrothermal, gas phase deposition and sol-gel method, etc. 

Heavy liquid method is the most accurate measure for nondestructive separation of material, and the most accurate method for accurately measuring the relative density of single grain material. Usually, the heavy liquid can be divided into three categories as following:

1. Halogen hydrocarbons which have the relative density within 0.86 ~ 3.32, but they are very easy to volatilize with a small viscosity and poison; 

2. Salt aqueous solution which has the big proportion, and easily soluble, with its relative density of 1.0 ~ 4.3, however, most of them are expensive, or with the property of unstable, toxicity, easy to react; 

3. Salts and their mixture with low melting temperature, while the specific gravity can reach to 4.7, and the nitrate or halide with mercury, silver, thallium, tin, antimony is generally used. The defect of this kind of heavy liquid is that the temperature should be raised when it is used, and mostly of them will easily react with water and minerals, and the extremely toxic. 

Composite cobalt - tungsten oxide powder is the main raw material for manufacturing cemented carbide powder, the finished product cemented carbide has been widely used in machinery manufacturing, oil exploration, military industry, aerospace and other fields because of its high hardness and density, wear-resisting and other special performance. 

 

Common methods for manufacturing composite cobalt - tungsten oxide powder by using the ammonium metatungstate (AMT) or metatungstate as raw material are like following:

Guaiacol, also known as adjacent hydroxyl benzoic ether or adjacent methoxy phenol, is the important fine chemical intermediate in spices, medicine, agriculture and dye and other industries, with its main utilizations as following:

1. Mainly used for the synthesis of vanillin, a rare type of broad spectrum of high-grade spice, the spices additive;

2. In the pharmaceutical industry, guaiacol is the intermediate of the expectorant cough medicine of potassium guaiacol sulfonate, and also the good fungicide;

3. It can be used as antioxidant to be applied in polymerization and food industry, and also can be used to determine copper, hydrocyanic acid and nitrite;

4. In the agriculture, 5 - nitro guaiacol sodium, which is formed through the steps of acetylation, nitration and hydrolysis from the raw material of guaiacol, is a kind of high efficient plant growth regulator that can quickly penetrate into the plant and promote the germination, striking root, growth, and bearing fruit of plant. 

 

Most of guaiacol productions are through chemical synthesis method, while the traditional production process exist serious environmental pollution, large cost and many useless by-products and other shortcomings. Therefore, the development and utilization of non-toxic, harmless and pollution-free production process of environmental friendly catalyst is the inevitable developing trend of chemical process in the future. 

 

Studies have pointed out one kind of supported solid catalyst with the active component of ammonium metatungstate (AMT) to catalyze alkylation reaction (which is also called as catechol with methanol gas solid phase alkylation reaction) of gasified catechol and methanol, and thereby to synthesize guaiacol. The properties of this production process are as follows:

1. The solid catalyst is taking tungsten ad active center, and the loading weight may be 5 ~ 15% of the total mass;

2. The catalytic reaction temperature is 533~573 k; 

3. The molar ratio of catechol and methanol is 1:5;

4. The preparation of the catalyst is using the traditional impregnation method, which is impregnating the 40 ~ 60 sieves of established silica particles in a certain amount of ammonium metatungstate aqueous solution for some time, then drying, and roasting under 533~773 k  for 3 hours to finally get ammonium metatungstate catalyst;

5. The production process with low production cost, low toxic and corrosive of raw materials and catalyst, little environment pollution.

Tungsten nitride is a kind of new catalytic material, which shows an excellent performance in hydrogenated desulfurization and denitrification; also, it can not only prevent the sulfur pollution caused by industrial catalyst presulfurization, but also have high selectivity in the hydrogenolysis of heteroatomic ring. 

Currently, the barium-tungsten which is widely used in the magnetron is limited, due to the strong electronic back in the device which makes the consumption of BaO is too fast and thus to result in the decrease of the device’s life; moreover, the secondary electron emission ability of it is difficult to meet the requirement of high power microwave device. Furthermore, due to the radioactive problem of Th, it is already suitable for some of the high power magnetron ThO₂ cathode. Study found that even through the rare earth - molybdenum metal ceramic cathode materials has a stable secondary electron emission performance, but its thermal emission performance is poor, and requires a higher temperature in magnetron start up, and thus to limit its using in the magnetron.