Ostwald Process

Introduction

• The Ostwald process is one of the most widely utilised procedures or chemical processes for producing nitric acid. Wilhelm Ostwald, a German scientist, invented the technique in the year 1902. In 1909, he was awarded the Nobel Prize for his research.
• The Ostwald method has grown in popularity over the years since it is the simplest way to manufacture nitric acid, which is utilised in a variety of applications including fertiliser manufacturing and the production of inorganic and organic nitrates or nitro compounds.

The Ostwald Process’s History

• Industrial nitrogen used to be nitrates that were processed with sulphuric acid to make nitrogen before the Ostwald Process.
• In addition to Haber’s nitrogen-fixing process, the Ostwald Process was primarily utilised during World War I. Later, when nitrogen use expanded, the process was employed for fertiliser production.
• Later in 1902, Ostwald patented and profited from the Process. Stainless steel was introduced to increase yield by increasing and supporting higher pressure.

The Basics of Primary Oxidation

• For the oxidation of ammonia, a catalytic chamber is employed, with platinum gauze as the catalyst and a temperature of 600 degrees. Nitric acid oxidation is both reversible and exothermic. According to Le Chatelier’s principle, lowering the temperature can accelerate the reaction. 95 per cent of ammonia is converted to nitric acid during initial oxidation.
• The nitric oxide gas produced by the oxidation of NH3 is hot, thus it is sent through a heat exchanger to lower the temperature to 150 degrees Celsius.

Haber’s Process and its Importance in the Ostwald Process

• Haber’s Process is the commercial synthesis of ammonia, which is a raw material in the Ostwald Process. With the use of ammonia, this process overcomes the difficulties of breaking down the energy in nitrogen and hydrogen, therefore aiding the Ostwald Process, as ammonia is the feedstock for this reaction.

Mechanism

• We may rapidly understand the idea or mechanism behind this Process before moving on to the various steps. The conversion of ammonia to nitric acid is merely the outcome of an oxidation reaction.
• This oxidation reaction provides us with the required nitric oxide. Furthermore, when nitric acid is oxidised, nitrous gases are produced, which can trap water molecules. We are in possession of We get nitric acid this way.
• Where ammonia will give rise to the desired product, catalytic oxidation with O2 is used. There are specific reaction chambers where ammonia is injected from one way and the air is fed through several paths while the process is being carried out.

Ostwald Process Reaction

The Ostwald Process is a chemical process used for the large-scale production of nitric acid (HNO₃). This process is a key industrial method and forms the basis of many nitrogen-based fertilizers and explosives.

Steps in the Ostwald Process Reaction

1. Ammonia Oxidation

Reaction:

In this step, ammonia (NH₃) is oxidized to nitric oxide (NO) using oxygen (O₂) from air.

• Temperature: ~900°C
• Catalyst: Platinum-Rhodium gauze

Reaction:

The nitric oxide (NO) is further oxidized to nitrogen dioxide (NO₂) in the presence of oxygen.

Reaction:

Nitrogen dioxide (NO₂) reacts with water (H₂O) to produce nitric acid (HNO₃) and nitric oxide (NO).

The nitric oxide (NO) is recycled back into the process.

Ostwald Process Equation

The Ostwald process equation refers to the chemical equations representing the industrial process used to produce nitric acid (HNO₃) from ammonia (NH₃). This process involves the catalytic oxidation of ammonia, followed by the absorption of nitrogen oxides in water. The key reactions in the Ostwald process are:

Step 1: Catalytic Oxidation of Ammonia

Ammonia is oxidized in the presence of a platinum or rhodium catalyst at high temperatures (around 800–900°C):

Step 2: Oxidation of Nitric Oxide

The nitric oxide (NO) produced in the first step is further oxidized to nitrogen dioxide (NO₂):

Step 3: Absorption in Water

Nitrogen dioxide reacts with water to produce nitric acid and nitrogen monoxide:

Overall Reaction:

The net equation for the Ostwald process, combining these steps, is:

This process is vital in the production of fertilizers, explosives, and other chemicals, as nitric acid is a key intermediate.