Technical breakthrough in the preparation of hydrazine hydrate using the hydrogen peroxide method

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　　　　　　　　　　　　　　　　　　　Technical breakthrough in the preparation of hydrazine hydrate using the hydrogen peroxide method. Hydrazine hydrate (N2H4·H2O) is an important chemical raw material that is widely used in fields such as pesticides, pharmaceuticals, dyes, intermediates, synthetic fibers, the separation of rare metals, explosives, and rocket fuels. 　　There are two main systems for the production of hydrazine hydrate: one is the Raschig process, urea process, and ketazine process, which use chlorine as the oxidizing agent; the other is the hydrogen peroxide process, which uses hydrogen peroxide as the oxidizing agent. When comparing the two methods, the one that uses chlorine as an oxidant presents various problems such as equipment corrosion, environmental pollution, and the need to handle the resulting inorganic salts; these issues make it difficult for this method to remain viable under the requirements of modern industrial environments. In contrast, the method that uses hydrogen peroxide as an oxidant does not have such drawbacks, which is why it has seen rapid development. 　　The production of hydrazine hydrate in our country began in the 1950s. After decades of development, the production processes have become mature, but to this day the country still relies on the urea method and the ketonazide method, which use chlorine as an oxidizing agent; in contrast, developed countries started using the hydrogen peroxide method for production as early as the 1980s. With the rapid development of industry, the demand for hydrazine hydrate is increasing year by year. Clearly, the production processes using chlorine as an oxidant, such as the urea method and the ketonazide method, can no longer meet the requirements of modern development; it has become imperative to adopt the hydrogen peroxide-based process for producing hydrazine hydrate. 　　Supply of hydrazine hydrate in China: In recent years, the production capacity of hydrazine hydrate in China has shown an upward trend, resulting in significant changes in the structure of production capacity. Statistical data show that in 2023, China’s production capacity for hydrazine hydrate was around 205,000 tons; by 2024, this capacity rose to approximately 225,000 tons, representing a 12% increase year-on-year and reaching a historical peak. 　　According to relevant data, based on market expectations and corporate plans, hydrazine hydrate is expected to see another production increase of around 82,000 tons by 2025, bringing its maximum production capacity to 307,000 tons at that time. 　　Our \"Research Team for Producing Hydrazine Hydrate via the Hydrogen Peroxide Method\" built upon the technology for \"synthesizing acetone dinitrile\", which was developed successfully 20 years ago. Overcoming numerous difficulties and through continuous efforts, and inspired by foreign production processes, we managed to tackle the challenge of hydrolyzing acetone dinitrile, thereby developing a simple yet distinctive production process for manufacturing hydrazine hydrate using hydrogen peroxide. 　　Due to constraints, we have only developed an intermittent production process for small-scale experiments. The experiment consists of two parts: the synthesis of butanone azide and the hydrolysis of butanone azide. The specific details of the experiment are described as follows. A. Synthesis of acetone azide 1. Experimental equipment: Equipment commonly used in chemical laboratories. 2. Synthesis of acetone azide: Acetone, ammonia water, solid and liquid catalysts, stabilizers, solvents, and process water are added to a four-necked flask in proportion. After mixing thoroughly, hydrogen peroxide is added slowly. The reaction temperature is maintained between 20–50°C, and the reaction duration is 3.5–4.0 hours. Once the reaction is complete, the solid catalyst is filtered out, and the filtrate is used for the subsequent hydrolysis step. The yield of acetone dinitrile is generally around 85%, with a maximum of over 88%. If an aqueous butanone solution recovered from synthetic butanone azide is used as the raw material for synthetic butanone azide, the yield can reach around 92%. The separated solid catalyst can be reused several times. B. Hydrolysis of acetone azide 1. Experimental equipment: Standard equipment used in chemical laboratories 2. Hydrolysis of acetone azide The acetone azide solution from which the solid catalyst has been removed is added to a four-necked flask; an appropriate amount of process water and a sufficient quantity of hydrolysis catalyst are also added. The mixture is heated slowly while stirring, until the liquid in the flask boils at around 80°C. Light components begin to distill at a temperature of around 60°C at the distillation head. As the temperature of the kettle gradually increases, components such as acetone and solvents are also slowly distilled off. When almost no distillate is produced at a distillation head temperature of 83°C, it is considered that the hydrolysis of acetone dinitrile has been completed. At this point, the temperature of the boiler liquid is around 101°C. The hydrolysis solution contains various catalysts and hydrazine hydrate. In industrial installations, after retaining the fractions above 83°C, the setup can be modified to continue distilling hydrazine hydrate without cooling, followed by further purification. The collected 83°C fraction is used as raw material for the next batch. In this process, the hydrolysis rate of acetone dinitrile is greater than 99%, with a yield of crude hydrazine hydrate of around 90%; the entire process takes approximately 1.5 hours. The small-scale experiment developed by our team for the production of hydrazine hydrate using the hydrogen peroxide method is merely the beginning of the application of this production technique in large-scale industrial facilities in China. We are willing to work closely with companies and research institutions interested in producing hydrazine hydrate to fully industrialize this process in China. 　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　R&D Team for the Preparation of Hydrazine Hydrate via Hydrogen Peroxide Method 　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　Lu Lianxiang (Engineer Lu) 13882799701 September 30, 2025