Method of synthesizing o-dibromobenzene by diazotization in one step at high temperature
A technology of ortho-dibromobenzene and diazotization, applied in chemical instruments and methods, organic chemistry, halogenated hydrocarbon preparation, etc., can solve problems such as low product yield, achieve high yield, stable product yield, reduce Energy consumption and effect of investment in refrigeration equipment
Active Publication Date: 2014-06-04
常州市正锋光电新材料有限公司
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Problems solved by technology
The traditional production method of o-dibromobenzene is produced by a two-step method of diazotization and decomposition reaction, and when the two-step method is used to produce o-dibromobenzene, the diazonium salt is prone to coupling, which makes the product yield low
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Embodiment 1
[0013] Put 500g of hydrobromic acid with a mass fraction of 48%, 10g of cuprous oxide, and 172g of o-bromoaniline into a four-necked flask equipped with a stirrer, condenser, and thermometer, stir and raise the temperature to above 80°C, and drop 72g of A solution of sodium nitrite dissolved in 100g of water, after dripping, change the distillation device with water to distill the product, separate the oil layer, wash once with 100mL of 5% liquid alkali, and then wash once with 100mL water, separate the oil layer , product 194g was evaporated under reduced pressure, content 99.2%, yield 82%. From figure 1 and figure 2 It can be confirmed that the final product obtained in the examples is o-dibromobenzene.
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The invention relates to the technical field of preparation of o-dibromobenzene, and particularly relates to a method of synthesizing o-dibromobenzene by diazotization in one step at high temperature. The method comprises the following steps: sequentially adding hydrobromic acid, cuprous oxide and bromaniline into a reactor with a stirrer, a condenser and a thermometer; heating to over 80 DEG C; maintaining the temperature within 80-100 DEG C; dropping aqueous solution of sodium nitrite under liquid level; after dropping, distilling with steam to obtain the product, and separating out the oil layer; washing once by thermonatrite; after washing once, distilling under reduced pressure to obtain a product. According to the preparation method of o-dibromobenzene provided by the invention, diazotization and decomposition reaction are carried out by using a one-step method, so that the energy consumption and investment on freezing equipment are greatly reduced, and the product is stable in yield, and yield fluctuation caused by refrigeration of a two-step method is avoided. The continuous production capacity is greatly improved, the quality of the product is consistent with that of the two-step method, the yield is slightly higher, the preparation process is simple, convenient and feasible, the product is good in quality, and the technical demand is low, so that the method is a method suitable for industrialized production.
Description
technical field [0001] The invention relates to the technical field of preparation of o-dibromobenzene, in particular to a method for synthesizing o-dibromobenzene in one step by diazotization at high temperature. Background technique [0002] O-dibromobenzene is a colorless or light yellow liquid, often used as a pharmaceutical intermediate. The traditional production method of ortho-dibromobenzene is produced by a two-step method of diazotization and decomposition reaction, and when the two-step method is used to produce ortho-dibromobenzene, diazonium salts are prone to coupling, resulting in low product yield. Contents of the invention [0003] The invention provides a method for synthesizing o-dibromobenzene by one-step diazotization at high temperature. The diazotization and decomposition reactions are carried out in one step, which greatly reduces energy consumption and investment in refrigeration equipment, and the product yield is stable without The yield fluctua...
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IPC IPC(8): C07C25/02C07C17/093
Inventor 徐小虎
Owner 常州市正锋光电新材料有限公司
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