What Is a Chlorinated Solvent?

Chlorinating agent is an agent that can promote the increase of chlorine atoms in organic matter through chlorination reaction. In organic chemical reactions, the chlorination reaction generally includes three aspects: replacement chlorination, addition chlorination and oxidative chlorination.

Chlorination generally refers to

Chlorinating agent is an agent that can increase the chlorine atom of organic matter. Commonly used chlorinating agents are phosphorus oxychloride, phosphorus trichloride, phosphorus pentachloride, Lucas reagent, a mixture of concentrated hydrochloric acid and anhydrous zinc chloride, Vilesmier-Haack reagent, dichlorosulfoxide , Sulfonyl chloride, chlorine. Phosphorus pentachloride and sulfoxide can also be used in some cases, such as the reaction of replacing the hydroxyl group with chlorine.

Tert-butyl hypochlorite is a highly effective chlorinating agent. It can be used for the chlorination of hydroxyl groups (such as the preparation of allyl chloride), the chlorination of ketones, and the photochlorination of N-chloro and ethers of some nitrogen-containing compounds. It is also often used as a high-efficiency oxidant, used to oxidize alcohols to ketones (aldehydes) or to form a-chloro ketones. It can also oxidize thioethers to sulfoxides.

Although the synthesis of tert-butyl hypochlorite has been reported for a long time, only simple methods for its synthesis have been reported in the literature. Since tert-butyl hypochlorite is a strong oxidant, it is easy to decompose and explode, and it is difficult to transport. Most of the experimental research or industrial raw materials are self-produced and self-produced, especially the effect of t-butyl hypochlorite on its purity has not been reported in the literature. Therefore, it is more important to study its synthetic process control and storage stability, especially for units that use tert-butyl hypochlorite in large quantities.

Sodium hypochlorite, tert-butanol and glacial acetic acid were used as raw materials to prepare tert-butyl hypochlorite. The effects of reaction temperature, reactant ratio, feeding method, and reaction time on the yield and purity of the product were examined; the storage time of the product affected its storage stability The purity, impurity content and product structure were characterized by chromatography-mass spectrometry. The results show that the optimal process conditions for the synthesis of tert-butyl hypochlorite are as follows: the molar ratio of sodium hypochlorite to glacial acetic acid is 1: 1, the molar ratio of sodium hypochlorite to tert-butanol is 1.4: 1, and the tertiary butanol and glacial acetic acid are fed at one time. The reaction temperature is o ° C. After 3 minutes of reaction, the yield of the product reached 72.2% and the purity reached 92%. The purity of the product decreased with the increase of storage time, and the content of the impurity t-butanol increased. Use of tert-butyl hypochlorite for chlorination of nickel-based butadiene rubber, H-NMR and

Chlorinating agent

The hydroxyl group of alcohol can be used by various chlorinating reagents such as hydrochloric acid solution and hydrochloric acid. Replaced by zinc chloride, phosphorus pentachloride, sulfoxide, etc. The most common method uses an aqueous solution of hydrogen halide, such as hydrochloric acid as a chlorinating agent. Because the presence of water is not conducive to the reaction, water-removing agents such as sulfuric acid, phosphoric acid, zinc chloride, etc. are often added: there are also solvents to perform azeotropic distillation to remove water. Recently, interfacial migrating agents (that is, surfactants, emulsifiers) have been used to make water-insoluble alcohols fully contact with hydrogen chloride to facilitate the reaction. Tertiary alcohols are easily substituted and can be reacted directly with hydrogen halides.

Zinc hydrochloride is a commonly used chlorinating reagent. This method is relatively simple. When linear primary alcohols are reacted, primary chlorohydrocarbons can be produced in good yields, but the substrate must be stable. The highly branched primary alcohols often undergo rearrangement to form tertiary halogenated hydrocarbons, which limits the application of this method to a certain extent.

Chlorinating agent

Thionyl chloride is one of the most effective chlorinating agents for alcohols. If you use sulfoxide to prepare chloroalkanes from alcohols, the advantage is that the reaction is irreversible. The intermediate product, chlorosulfite, automatically decomposes HCl and sulfur dioxide, both of which are gases. Because they are constantly leaving the system, it is beneficial to make the reaction proceed toward the product, and there are no other by-products in the end. The separation and purification of chlorinated hydrocarbons is particularly convenient. In industrial production, lye is commonly used for absorption. If chlorine gas and phosphorus trichloride are reacted with the generated sulfur dioxide, thionyl chloride is obtained and can be recycled, which has a good application development prospect.

Chlorinating agent

The reaction of phosphorus halides with alcohols is a good way to prepare halogenated hydrocarbons. In this way, the addition reaction of hydrogen halide and olefinic bonds does not occur in the preparation of halogenated olefins, especially in the presence of pyridine. It is more convenient to use halogen (bromine, iodine) and phosphorus to react with alcohol immediately after the formation of phosphorus halide, but for halogenation of enol, phosphorus halide and pyridine must be used. G. A. Wiley also studied the method of converting alcohols to their chlorides. He used triphenyl phosphorus and chlorine gas as chlorinating reagents and reacted in DMF solvent at 200 ° C for 1 to 2 hours with a yield of 92%. The alcohol is converted into a chloride. ^[3]