Method for preparing dibromomethane and methylene chlorobromide by one-pot

A technology of dibromomethane and bromochloromethane, applied in the direction of halogen substitution preparation, organic chemistry, etc., can solve the problems of bromochloromethane selectivity reduction, influence on reaction, etc., achieve the effect of increasing product yield and simplifying the process

Inactive Publication Date: 2009-02-04
SHANDONG DADI SALT CHEM GROUP
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Problems solved by technology

However, this production process is due to the metal Na in NaBr + The passivating effect of the reaction makes the selectivity of bromochloromethane greatly reduced, thereby affecting the progress of the reaction

Method used

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  • Method for preparing dibromomethane and methylene chlorobromide by one-pot
  • Method for preparing dibromomethane and methylene chlorobromide by one-pot
  • Method for preparing dibromomethane and methylene chlorobromide by one-pot

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Embodiment

[0045] Embodiment, one-pot method produces the preparation method of methylene bromide, bromochloromethane, and described preparation method comprises the following steps:

[0046] ①Hydrogen production process

[0047] Make a solution of methanol and pure water in a weight ratio of 1:1, inject it into the reactor with a metering pump, and produce H under the conditions of mixing and pressurizing to 280°C. 2 , CO 2 , through pressure swing adsorption and purification treatment to obtain hydrogen with a purity of 99.9%;

[0048] ②Hydrogen bromide synthesis process

[0049]Turn on the quartz resistance furnace, and when the temperature of the furnace rises to 700°C, open the exhaust valve, flush nitrogen to replace the air in the calciner, and mix 3.1kg of purified hydrogen with 229.4kg of bromine, that is, the molar ratio is 1:1 Pass it into a quartz glass synthesis furnace at a temperature of 700°C to synthesize hydrogen bromide gas, then debrominate it, dry it with molecula...

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Abstract

The invention discloses a method for preparing dibromomethane and bromochloromethane by a kettle method, which adopts the following processes: hydrogen bromide and dichloromethane react to obtain dibromomethane; methanol is reacted with water to obtain pure hydrogen; the hydrogen is then reacted with bromine to obtain hydrogen bromide gas; the hydrogen bromide gas is then purified until the purity is above 98 percent, thus ensuring that the side effect brought to the reaction by the hydrogen can be reduced to the lowest; the hydrogen bromide gas and the dibromomethane are added into a reaction kettle for reaction; after the operations of washing, distilling, and the like, the dibromomethane and bromochloromethane with high purity can be obtained from reactants; the dichloromethane is used for the combined production of dibromomethane and bromochloromethane, which is the most direct and economical way, and the method is characterized by no introduction of other impurities, no by-products, the high quality of products and no pollution of three-waste.

Description

technical field [0001] The invention relates to a preparation method for producing dibromomethane and bromochloromethane by a one-pot method. Background technique [0002] Dibromomethane is the raw material of various organic compounds. For example, in the synthesis of pesticides, it is used to synthesize myclobutanil, dithiocyanomethane, ethion, etc. The former is a high-efficiency and low-residue pesticide vigorously promoted by the country. [0003] As an intermediate of medicine, pesticide, fungicide and water treatment agent, bromochloromethane is an important fine chemical raw material. [0004] The English name of dibromomethane is Dibromomethane, which is a colorless or light yellow transparent liquid with a density of 2.4970g / cm 3 (20°C), melting point -52.7°C, boiling point 96.5°C, refractive index 1.542, solubility in water 1.17g / 100g (15°C), easily soluble in alcohols, acids, and esters. As a pesticide intermediate, dibromomethane is the main raw material for t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C19/075C07C17/20
Inventor 王纯洁宋永良李迎堂袁彦明袁彦强
Owner SHANDONG DADI SALT CHEM GROUP
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