How to use ammonia to make nitric acid in industry.

3. Preparation method of nitric acid.

1) Industrial method - catalytic oxidation of ammonia.

Main raw materials: NH3, air, water.

Production principle: 4NH3 5O2 4NO 6H2O

2no＋o2＝2no2

3no2＋h2o＝2hno3＋no

Exhaust gas absorption: 2NO2 2NAOH nano3 nano2 H2O

no＋no2＋2naoh＝2nano2＋h2o

Concentration of HNO3: Mg(NO3)2 or concentrated H2SO4 is used as an absorbent to obtain fuming nitric acid from distillation.

Note: The total reaction can be obtained from 2no o2 2no no2 h2o 2hno3 no:

4no2＋o2＋2h2o＝4hno
no＋3o2＋2h2o＝4hno3

In the process of industrial nitric acid production, 1 mol NH3 can theoretically be prepared from 1 mol NH3 due to the cyclic oxidative absorption

There is a chemistry book on it: 4NH3+5O2 4NO+6H20 (there is a catalyst at the arrow: iron catalyst).

2no+o2=2no2

3no2+h2o=2hno3+no

However, ammonia must be synthesized first, and nitrogen is ...... by liquefied air separationn2(g)+3h2(g)=2nh3(g)

Nitric acid is prepared by ammonia gas, and ammonia is dissolved in water to form ammonia (that is, ammonia monohydrate) and dilute nitric acid to form ammonium nitrate. The formula is as follows:

4NH3 + 5O2 = 4NO+6H2O (condition: catalyst, heating) 2NO+O2=2NO2

3no2+h2o=2hno3+2no

The total equation is: NH3+2O2=Hno3+H2ONh3+H2O=NH3·H2O

NH3·H2O+HNO3=NH4NO3+H2O Nitric acid is a strong acid, which is a colorless liquid at room temperature. It is volatile, soluble in water, and has strong oxidizing and corrosive properties. Unstable and easily decomposes into water, nitrogen dioxide, and oxygen.

However, nitric acid is still nitric acid when it volatilizes, and it is easy to decompose does not mean that what is volatilized is the product of decomposition!

Ammonia is first oxidized to nitrogen dioxide to produce nitric acid, and then reacted with ammonia to produce ammonium nitrate. In addition, ammonium nitrate is an explosive product, and you need to have the corresponding production qualifications.

Steps. 1. Use ammonia to make nitric oxide.

4NH3+5O2==4NO+6H2O (Catalyst, heating) on the equal sign

Steps. 2. Use nitric oxide to make nitrogen dioxide.

2no+o2==2no2

Steps. 3. Nitrogen dioxide is used to produce nitric acid.

3no2+h2o==2hno3+no

or 4NO2+O2+2H2O==4HNO3

Step 4: Sun Nian, use the remaining ammonia gas and nitric acid to react to make ammonium nitrate.

nh3+hno3==nh4no3

Ammonium nitrate physicochemical properties.

Pure ammonium nitrate is a colorless and odorless transparent crystal or a small white particle crystal, which reacts with alkali to produce ammonia gas and absorb the amount of heat. It is deliquescent and easy to agglomerate. Soluble in water and heat absorption, soluble in acetone, ammonia, slightly soluble in ethanol, insoluble in ether.

Thermal decomposition: Ammonium nitrate is decomposed at different temperatures, and the decomposition products are also different.

At 110 °C: NH4NO3 NH3+HNO3

At 185 200 °C: NH4NO3 N2O + 2H2O

When above 230 °C, there is low light at the same time: 2NH4NO3 2N2+O2+4H2O

When above 400 °C, vigorous decomposition occurs**: 4NH4NO3 3NH2+2NO2+8H2O

Pure ammonium nitrate is stable at room temperature and is not sensitive to blows, collisions, or friction. However, ammonium nitrate can not be detonated when the water content is more than 3%, but it will still decompose at a certain temperature, and the safety regulations must be strictly observed in the production, storage, transportation and use of Gaokai.

Industrial synthesis of nitric acid.

1。Ammonia oxidation.

The nitric acid industry is closely related to the synthetic ammonia industry, and the ammonia oxidation method is to produce concentrated nitric acid in industrial production.

The main route of the acid, its main process is the mixture of ammonia and air (oxygen:nitrogen 2:1) into the hot (760 840) platinum rhodium alloy mesh, under the catalysis of the alloy mesh, the ammonia is oxidized to nitric oxide (NO).

The resulting nitric oxide uses the residual oxygen from the reaction to continue oxidizing to nitrogen dioxide, which is then introduced into water to produce nitric acid. The preparation of dilute nitric acid, concentrated nitric acid, and fuming nitric acid is different in process.

4nh₃（g）+ 5o₂（g）—pt-rh→ 4no（g）+ 6h2o（g）

2no（g）+ o₂（g）——2no₂ （g）

3no₂（g）+ h2o（l）——2hno₃（aq）+ no（g）

2。Other. Concentrated sulfuric acid and saltpeter have also been used in industry to make nitric acid, but the method consumes a lot of acid and the equipment is seriously corroded, so it is basically out of use.

nano₃（s）+ h2so₄（l） —nahso₄（s）+ hno₃（g）

4NH3 + 5O2 ==4NO + 6H2O, (condition is high temperature and pressure, catalyst, reversible symbol).

2no + o2 ==2no2

3no2 + h20 ==2hno3 + no

Step 1. Ammonia reacts with oxygen in the presence of a catalyst such as platinum to form nitric oxide.

4nh3+5o2=4no+6h20

Write catalyst above the equal sign and heat symbol below ).

Step 2. Nitric oxide is combined with oxygen to produce nitrogen dioxide.

2no+o2=2no2

There is no need to write other symbols on the equal sign).

Step 3. Nitrogen dioxide dissolves in water to produce nitric acid and water.

3no2+h2o=2hno3+no

There is no need to write other symbols on the equal sign).

In the first step, the chemistry textbook has an equal sign, not a reversible sign.

Industrially, nitric acid is produced from ammonia, and the yield of this reaction is about 60%.

Ammonia can be reacted with oxygen under certain conditions to produce nitrogen dioxide, and then nitrogen dioxide is dissolved in water, which is nitric acid.

4nh3+5o2==4no+6h20

2no+o2=2no2

4no2+o2+2h2o=4hno3

4NH3+5O2=4NO+6H20 Condition Heating PT as catalyst Place: oxidation furnace.

2no+o2=2no2

3NO2 + H2O = 2HNO3 + No NO Recycling Place: Absorption tower This is called ammonia catalytic oxidation method to produce nitric acid.