Methoxypyridine
Preparation background and overview of ammonium pentaborate (tetrahydrate)
Ammonium pentaborate (tetrahydrate) chemical formula is NH4B5O8·4H2O. Colorless orthorhombic bipyramidal crystal. Soluble in water, insoluble in alcohol. It is stable at 0 to 90°C. When heated to above 90°C, it decomposes and releases ammonia. At high temperatures, it is converted into boron trioxide with a small amount of ammonia. Ammonium pentaborate (tetrahydrate) can be prepared from boric acid and ammonia (or borax and ammonium chloride).
Preparation and use of ammonium pentaborate (tetrahydrate)
Ammonium pentaborate (tetrahydrate) can be used as boron compound intermediates, telecommunications equipment, fire retardants, detergents, and in glass manufacturing, wood processing, high-temperature technology, and medicine. For example, it is used to prepare boron and nitrogen co-doped porous carbon materials for supercapacitors. This method uses fir bark as the raw material of hydroxymethylbenzene boric acid, and ammonium pentaborate (tetrahydrate) as the boron source and nitrogen source. First, through Microwave hydrothermal assisted boron and nitrogen heteroatom doping, and then high-temperature pyrolysis to obtain boron and nitrogen co-doped porous carbon materials. The boron content is 10.19~13.05wt%, the nitrogen content is 15.13~19.5wt%, and the specific surface area can reach 820~955m/g. The present invention realizes heteroatom doping and prepares high specific surface area carbon materials through microwave-assisted hydrothermal and high-temperature pyrolysis. It is easy to operate and greatly shortens the preparation time of carbon materials. At the same time, no strong acids, alkalis and toxic reagents are used in the preparation process. The process is environmentally friendly, and the boron-nitrogen co-doped porous carbon material produced has certain application prospects in the field of supercapacitors.
Preparation of ammonium pentaborate (tetrahydrate)
A method for the co-production of ammonium tetraborate and ammonium pentaborate, the steps are as follows:
1. Acid is purified by recrystallization;
2. Weigh 28kg of concentrated ammonia water and put it into a stainless steel reactor;
3. Take 45kg of purified boric acid, stir and slowly add it to the ammonia water;
4. The temperature should be controlled between 35±2℃, the stirring speed should be slow, and the feeding speed should be slow;
5. After adding the acid, the solution is basically clear, stop stirring and heating;
6. Pour water into the jacket of the reaction kettle, cool it down to 20°C, start stirring until a large amount of precipitation precipitates, stop stirring, and leave it overnight (temperature is controlled at 15±2°C);
7. Pick up the solid precipitate, spin it dry, collect the mother liquor, spin the solid dry, and dry it naturally. The finished product is ammonium tetraborate, with a content of 99% and a yield of 85%. Other impurities are also in full compliance with analytical grade (AR) specifications. ;
8. Combine the collected mother liquor with the mother liquor left in the reaction kettle, and conduct testing. The mother liquor contains approximately 7% ammonium tetraborate;
9. Inject 49kg of 1:1 ammonia solution into the above mother liquor, and slowly add 55kg of purified boric acid. The operating conditions are the same as ammonium tetraborate;
10. After the boric acid is added and the reaction solution is basically clear, stop heating and stirring, inject cold water into the interlayer to cool and stir. When the temperature is lower than 15°C, stop stirring, cool and leave overnight (temperature is controlled at 12±2°C) , precipitating a large amount of precipitation;
11. Remove the sediment and shake dry. Collect the mother liquor, put the dried solid into a dryer, and dry it at 75°C. The finished product is ammonium pentaborate, with a content of 99% and a yield of 90%. Other impurities are also in full compliance with analytical grade (AR) specifications;
