Hydrazine hydrate substance

Hydrazine hydrate; Diamine hydrate; Hydrazinium hydroxide; Monohydrate of hydrazine; Diamide hydrate. Molecular formula: H4N2·H2O. Molecular weight: 50.06. CAS number: 7803-57-8. Properties: Colorless fuming liquid, weakly alkaline, with a distinctive odor; flammable. Melting point: -51.7°C, boiling point: 120.1°C at 47°C (3.33 kPa); relative density: 1.032 at 21/4°C; refractive index: 1.4280. Flash point (open cup) 73°C. It will catch fire and decompose when in contact with highly reducible metal oxides such as mercury and copper, as well as porous oxides. It is miscible with water and ethanol, but insoluble in chloroform and ether. It can absorb carbon dioxide from the air. It is corrosive to materials such as glass and rubber. Preparation method: There are various production methods. 1. In the urea oxidation method, a 10% sodium hypochlorite solution is mixed with 30% liquid alkali, then cooled; the mixture is adjusted again, and once more cooled to achieve a weight ratio of chlorine to alkali of 1:1.8, after which it is placed in a reaction vessel. Add an appropriate amount of potassium permanganate, then add the urea solution to the reaction vessel while stirring, and heat it to about 103–104°C until the mixture boils. The amount of urea added is calculated based on available chlorine, with a weight ratio of 76:75 for available chlorine. The aforementioned crude hydrazine hydrate obtained from oxidation was added to an evaporator for vacuum evaporation; hydrazine gas and water vapor were introduced into a receiving vessel via a dead air device for initial concentration. Concentration is initially carried out in the receiving kettle. The hydrazine hydrate solution obtained from the absorption kettle is sent to a sieve plate tower for vacuum concentration to bring the content of hydrazine hydrate to the specified value. When the content is ≥40%, urea is used; for sodium hypochlorite, the value is 8900; for 30% caustic soda, it is 5200. In the ammoniaation method using sodium hypochlorite, sodium hypochlorite is first prepared from chlorine gas and caustic soda, and then synthesis is carried out at a pressure of 3.922×107 Pa and a temperature of 130–150°C to obtain a hydrazine hydrate reaction mixture. Excess ammonia is removed through stripping, followed by evaporation for desalination and distillation to yield the final product, hydrazine hydrate. Recent methods for producing hydrazine hydrate include the methylenedianiline method and the hydrogen peroxide method. The methylhydrazine nitration method is a new technology developed abroad in the 1970s. This method involves oxidizing ammonia in the presence of an excess of propane using chlorine or sodium hypochlorite to produce methylenedianiline, which is then hydrolyzed under pressure to yield hydrazine. The advantage of this method is its high yield, which can reach around 95%, along with low energy consumption. The downside is that the addition of propylene results in the formation of organic by-products in the system, which need to be removed, and the propylene vapor also requires treatment. The hydrogen peroxide method was successfully developed in France by the Guignard-Courmane Chemical Company. In 1979, a plant with an annual production capacity of 5,000 tons (100%) of hydrazine in water was built. This method involves the reaction of ammonia and concentrated H2O2 in the presence of acetamide and disodium hydrogen phosphate, resulting in the formation of methylenedianiline and water; subsequent hydrolysis under pressure yields hydrazine hydrate. The yield of hydrazine, calculated as H2O2, is about 75%. This method produces no by-product of sodium chloride, which is advantageous for simplifying the process and reducing environmental impact; moreover, the product can be easily separated without the need for distillation. However, the chemical loss in case A and B is higher than that in case C using the method of connecting nitrogen in case A. Uses: Hydrazine hydrate is a strong reducing agent and serves as a raw material in the pharmaceutical, pesticide, dye, foaming agent, imaging agent, and antioxidant industries ； An extensive amount is used as a deoxidizer for water in large boilers ； It is also used in the production of high-purity metals, synthetic fibers, and the separation of rare elements. In addition, it is also used to manufacture rocket materials and **, etc. It is also used as an analytical reagent. Most of the hydrazine derivatives used as blowing agents are azodicarbonamide (AC), as well as hydrazine tolsulfonate, among others. As derivatives used in medicine, the hydrazine derivatives that are commonly used include isoniazid, phenylthiourea, and benzene sulfonylthiourea. Other examples include the antipsychotic drug 1-isoniazyl-2-isopropylhydrazine, anticancer agents that are aldehyde hydrazine derivatives, anti-infective drugs that are 5-nitrofuranmethylenhydrazine derivatives, the antibiotic azolinocephalosporins, the diuretic and antihypertensive drug hydralazine, and anticancer drugs that are hydrazine derivatives. Hydrazine derivatives used as pesticides include the plant growth regulator maleic hydrazide derivatives, the rodenticide diphacinone hydrazide, the fungicidal pyrazole derivatives and 5-nitrofuranthiazole, as well as the herbicide aminotriazole. In Japan, over one-third of the uses of hydrazine are as a deoxidizer for boiler water; hydrazine derivatives used as foaming agents (including hydrazine hydrate and hydrazine sulfate) account for about 30%, while those used in sedatives make up 10%.

This post was last edited by qugd on 2016-12-28 at 13:28. They are not the same thing; hydrazine refers to anhydrous hydrazine, whose molecular formula is N2H4, with no bound water. Hydrazine hydrate is a substance in which the hydrazine molecule contains one bound water molecule. These are two different substances, and their physicochemical properties vary. Below are the properties of hydrazine: Hydrazine; Anhydrous hydrazine; Anhydrous hydrazine; Hydrazine; hydrazine anhydrous; hydrazine base; hydrazyna; hydrazyna (Polish); Nitrogen hydride; Hydrazin; Diamid. CAS number: 302-01-2. Molecular formula: H4N2. Molecular weight: 32.04. Chinese name: Hydrazine ； Anhydrous hydrazine ； Anhydrous hydrazine English name: Hydrazine ； anhydrous hydrazine ； hydrazine base ； hydrazine ； hydrazine (Polish) ； hydridine ； Hydrazin ； Description of Diamid properties: colorless oily liquid. Melting point: 2°C, boiling point: 113.5°C, relative density: 1.004 (25, 4°C), refractive index: 1.4644 (35°C). Flash point 52°C. It is miscible with water and alcohols, insoluble in chloroform and ether; it is hygroscopic, emits fumes in air, and produces a purple flame when burned. During distillation, an explosion can occur if there is a small amount of air present. It has a pungent ammonia smell. Production method: The industrial production of hydrazine has always relied on the Raschig process. In October 1981, France’s Genina-Courman company successfully developed the imine peroxide oxidation method, which is a very promising production technique. Rashifa produces hydrazine from ammonia and sodium hypochlorite through chlorination and amination: ammonia and sodium hypochlorite are fed into the reactor in a 1:3 molar ratio to yield chloramine as a by-product of the reaction. Chloramine then reacts with anhydrous ammonia in a hydrazine reactor to produce hydrazine. Urea can be used as a starting material; in the presence of potassium permanganate as a catalyst, urea reacts with a sodium hypochlorite-sodium hydroxide solution to produce hydrazine (see hydrazine hydrate). Use: Ammonia is a widely used chemical raw material. It has a very high heat of combustion and can be used as fuel for rockets and fuel cells. Hydrazine is a strong reducing agent that can be used to remove oxygen from boiler water and hot water heating systems in order to reduce corrosion. In the hydrazine molecule, due to the presence of two nucleophilic nitrogens and four hydrogen atoms that can be displaced, various derivatives can be synthesized, including plastic blowing agents ； Antioxidant ； Various polymers ； Polymer crosslinking agents and chain extenders ； Pesticides ； Herbicides ； Plant growth regulators and pharmaceuticals, etc. Hydrazine is highly toxic. The oral LD50 in mice is 59 mg/kg, and the intravenous LD50 is 57 mg/kg.

Another question is: hydrazine is on the list of highly toxic substances, but hydrated hydrazine is not. Why then should it be treated as a highly toxic substance when making purchases? Is it because hydrated hydrazine, despite not being on the list, is still considered a highly toxic substance?

You just need to compare the toxicity of liquid ammonia with that of ammonia water.