Preparation method of lithium isopropoxide_Industrial additives

Background and overview^[1]

Lithium isopropoxide, white or light brown powder, decomposes by absorbing water, and is soluble in organic solvents such as alcohol, benzene, and tetrahydrofuran. Used in organic synthesis, additives, etc.

Preparation^[1]

Lithium methoxide, lithium ethoxide, lithium n-butoxide, lithium tert-butoxide, and lithium isopropoxide are used in medicine, chemical industry, organic synthesis, phase transfer catalysts, and oxygenated acid inhibitors (used). They are basically used in the market at present. No high-purity (content: ≧98%) solid product was found. Since the reaction between alcohol and metallic lithium is an instantaneous reaction, it usually takes 1-15 minutes to complete the reaction. A large amount of hydrogen and heat are released during the reaction, which is easy to catch fire and explode, and is very dangerous, making it difficult for the product to be industrialized.

CN200810159591.1 provides a production process for lithium alkoxide, industrialized production, and high product purity.

The production process of lithium alkoxide of the present invention is characterized by adding metallic lithium into the reactor, slowly adding alcohol dropwise at 20 to 30°C, and during the reaction process, ice water is provided outside the reactor to cool down to a reaction temperature of 60~80℃, after the alcohol is added dropwise, the reaction is completed by insulating to obtain liquid lithium alkoxide. The invention is suitable for the production of lithium methoxide, lithium ethoxide, lithium n-butoxide, lithium tert-butoxide, lithium isopropoxide or other lithium alcohols. The mass content of lithium ethoxide in the obtained liquid lithium ethoxide is 17.5~20%, the mass content of lithium tert-butoxide in the liquid lithium tert-butoxide is 17.5~20%, and other liquid lithium alcohols (lithium methoxide, lithium n-butoxide, lithium isobutoxide) The mass content of lithium alkoxide in lithium propoxide is 28.5~30%. The appearance of the obtained solid lithium ethoxide is white crystalline powder, the lithium ethoxide content (high purity) reaches 98-99%, the free alcohol is ≦0.5%, and the moisture content is zero. The appearance of solid lithium methoxide is white crystalline powder, the content of lithium methoxide (high purity) reaches 98-99%, the free alcohol is ≦0.5%, and the moisture content is zero. The appearance of lithium n-butoxide is white crystalline powder, the content of lithium n-butoxide (high purity) reaches 98.5-99%, the free alcohol is ≦0.5%, and the moisture content is zero. The appearance of lithium isopropoxide is light yellow crystal powder, the content of lithium isopropoxide (high purity) reaches 98-99%, and the moisture content is zero.

For example:

Synthesis of lithium ethoxide: Figure 1 is a schematic structural diagram of the reaction device, which is intended to facilitate the explanation of the process of the present invention. Add 15kg of metallic lithium and measured 1000kg of ethanol into the 2000L reaction tank. Before starting the dripping, first turn on the ice water to cool down, and the temperature drops to ‑20~‑26°C. Then start dripping the measured alcohol (usually the dripping is completed within 7 hours). The dripping should be started slowly through the metering tank. , when the dropwise addition reaches 200L, close the ice water cooling valve and let the temperature begin to rise slowly. The temperature is controlled at 60-80 degrees (preferably 65-70°C). During the reaction process, all four exhaust valves must be opened, and four exhaust valves must be opened. All cooling valves of the first stage condenser are opened. The gas components are condensed through the condenser, and the alcohol in it is condensed and refluxes through the collection tank to the reaction tank. After normal operation, only two primary condensers can be used. If smoke is found in the reaction tank, quickly introduce argon gas through the safety valve or replace it with nitrogen, and close the valve of the ethanol meter. After everything is normal, start the dripping reaction again. After the reaction is completed, keep warm for 2 hours. At the end of the reaction, first close all exhaust valves to prevent moisture from entering the reaction tank, affecting product quality and causing accidents. After one hour, the liquid lithium ethanol is transported to the dryer to wait for concentration and drying. The mass content of lithium ethoxide in liquid lithium ethoxide is 18.5%. The closed drying equipment is a rake dryer, with a controlled vacuum degree of 0.01 to 0.1Mpa (stepwise negative pressure), a temperature of 100°C, and a drying time of 12 hours. Obtain white crystalline powdery solid lithium ethoxide. After testing, the mass content of lithium ethoxide is 99%, free alcohol is <0.5%, and the moisture content is zero.

Synthesis of lithium isopropoxide:

Different from lithium ethoxide, 15kg of metallic lithium is added to the reaction tank and 1000kg of isopropyl alcohol is added to the alcohol metering tank. The mass content of lithium isopropoxide in liquid lithium isopropoxide is 29.5%. Control the vacuum degree in the rake dryer to 0.01~0.1Mpa, the temperature to 100°C, and the drying time to 16 hours. Solid lithium isopropoxide was obtained as a light yellow crystalline powder. After testing, the mass content of lithium isopropoxide is 99%, free alcohol is <0.5%, and the moisture content is zero.

Main reference materials

[1] CN200810159591.1 Production process of lithium alkoxide