Manufacturing method of chloromethane
Chloromethane is an important organic chemical raw material, widely used in medicine, pesticide, refrigerant, solvent and other fields. There are mainly the following manufacturing methods:
I. Methanol method
Methanol method is the main method of producing chloromethane at home and abroad, and its process principle is to react methanol and hydrogen chloride gas to generate chloromethane and water under the action of catalyst. This method has the advantages of easy to obtain raw materials, simple operation and mild reaction conditions, but there are also problems such as easy deactivation of catalyst and corrosion of equipment.
1. Reaction principle
Methanol and hydrogen chloride gas under the action of catalyst, the substitution reaction occurs to generate chloromethane and water:
CH3OH + HCl → CH3Cl + H2O
2. Technological process
The technological process of chloromethane production by methanol method mainly includes the following steps:
(1) Mixing of methanol and hydrogen chloride gas: Methanol and hydrogen chloride gas are mixed according to a certain proportion and enter into the reactor. Mixing and entering into the reactor.
(2) Reaction: Under the action of catalyst, methanol and hydrogen chloride gas undergo substitution reaction to form chloromethane and water. The reaction temperature is generally 200-300℃ and the pressure is 0.5-2MPa.
(3) Separation: The reaction products are cooled and separated to obtain chloromethane and water. Chloromethane is purified by distillation to get qualified products.
Two, methane method
Methane method is a traditional method of producing chloromethane, and its process principle is to react methane with chlorine gas under the condition of light or heating to produce chloromethane and hydrogen chloride. The method has the advantages of abundant raw materials and low cost, but the reaction conditions are harsh, requiring high pressure and high temperature conditions.
1. Reaction Principle
Methane and chlorine gas react under light or heating conditions, and a substitution reaction occurs to produce methylene chloride and hydrogen chloride:
CH4 + Cl2 → CH3Cl + HCl
2. Process Flow
The process of producing chloromethane by methane method mainly consists of the following steps:
(1) Mixing: Methane and chlorine gas are mixed according to a certain proportion, and enter into the reactor.
(2) Reaction: Under the condition of light or heating, methane and chlorine gas undergo substitution reaction to produce chloromethane and hydrogen chloride. The reaction temperature is generally 400-500℃, and the pressure is 1-10MPa.
(3) Separation: The reaction products are cooled and separated to obtain chloromethane and hydrogen chloride. Chloromethane is purified by distillation to get qualified products. Hydrogen chloride can be recycled and utilized as raw material for producing chloromethane.
Third, acetic acid method
Acetic acid method is a new method to produce chloromethane, and its process principle is to react acetic acid and hydrogen chloride gas to generate chloromethane and acetic anhydride under the action of catalyst. This method has the advantages of easy availability of raw materials, mild reaction conditions, high catalyst activity, etc., and is one of the hot spots of current research.
1. Principle of reaction
Acetic acid and hydrogen chloride gas under the action of catalyst, the substitution reaction occurs to generate chloromethane and acetic anhydride:
CH3COOH + HCl → CH3Cl + (CH3CO)2O
2. Technological process
The technological process for the production of chloromethane by the acetic acid method mainly consists of the following steps:
(1) Mixing: Acetic acid and hydrogen chloride gas are mixed according to a certain Mixing: Acetic acid and hydrogen chloride gas are mixed in a certain proportion and enter into the reactor.
(2) Reaction: Under the action of catalyst, acetic acid and hydrogen chloride gas undergo substitution reaction to produce chloromethane and acetic anhydride. The reaction temperature is generally 150-250℃ and the pressure is 0.5-2MPa.
(3) Separation: The reaction products are cooled and separated to obtain chloromethane and acetic anhydride. Chloromethane is purified by distillation to get qualified products. Acetic anhydride can be recycled and utilized as raw material for producing chloromethane.
In short, there are various manufacturing methods of chloromethane, and different methods have different advantages and disadvantages and scope of application. In actual production, suitable manufacturing methods should be selected according to specific conditions to ensure product quality and production efficiency.
