Background and overview[1][2]
Diethylene glycol, also known as diethylene glycol, forms an ester when reacting with acid anhydride. It reacts with alkyl sulfate or halogenated hydrocarbon to generate ether. It is mainly used as a gas dehydrating agent and extraction agent, and also as a lubricant and finishing agent for textiles. Derived from the interaction of ethylene oxide and ethylene glycol. Diethylene glycol has been widely used in various cosmetics as a solvent, heat preservation agent, and viscosity control agent. It has been used in my country for nearly 20 years, and no problems have been found during this period. In April 2007, a Chinese-made “diethylene glycol toothpaste” scandal swept the world, which brought diethylene glycol to public attention and caused huge losses to my country’s toothpaste industry. The General Administration of Quality Supervision, Inspection and Quarantine issued an announcement on July 12, 2007, banning the export and import of toothpaste products containing diethylene glycol. Toothpaste manufacturers are not allowed to use diethylene glycol as raw materials. The standard set by the European Scientific Committee on Food is that the daily intake of diethylene glycol per person should not exceed 0.5 mg/kg. However, so far, there is no unified standard at home and abroad to evaluate the health risks caused by diethylene glycol in cosmetics, and the literature available for reference is very limited.
Application What are antioxidants[3-4]
1. Synthesis of diethylene glycol amine by low-pressure method from diethylene glycol
Diethylene glycolamine, also known as 2-(2-aminoethoxy)ethanol, is a colorless syrupy liquid. It is an important solvent and organic raw material. It can dissolve with water, dissolve aromatic hydrocarbons and absorb acid. Gases (H2S and CO2). Diethylene glycolamine is mainly used as an absorbent, surfactant, wetting agent, and desulfurizer for acidic gases. It can also be used as a raw material for polymers and is widely used in metal, electronics, medicine and other industries. Diethylene glycol amine can be obtained by the catalytic amination reaction of diethylene glycol and ammonia in the presence of a catalyst. The reaction process is as follows:
CN201410442739.8 provides a method for synthesizing diethylene glycol amine by a low-pressure method of diethylene glycol, enabling the industrial production of diethylene glycol amine products in China, filling the domestic gap, and breaking the foreign technology monopoly. The present invention is a method for synthesizing diethylene glycol amine by a low-pressure method of diethylene glycol. The specific process is as follows:
1. Before feeding the reaction, replace the air in the reactor with nitrogen, and then continuously pass preheated hydrogen into the reactor to raise the temperature of the catalyst in the reactor to 180-240°C. The pressure rises to 1.60-1.75MPa;
2. Vaporize liquid ammonia and mix it with hydrogen to obtain a mixed gas, and preheat the mixed gas to 240-280°C;
3. Mix diethylene glycol and soft water to obtain a mixed liquid, and preheat the mixed liquid to 230-280°C;
4. Send the preheated mixed gas in step 2 and the preheated mixed liquid in step 3 into the reactor in step 1, and conduct gasification in the presence of catalyst at 1.60-1.75MPa and 180-240°C. The liquid-phase catalytic ammoniation reaction (the reaction is a continuous reaction) obtains a crude product. After cooling, the crude product is separated into gas and liquid through a gas-liquid separator. The main components of the gas are hydrogen and ammonia, which can be recycled; the liquid is crude dihydrogen. Ethylene glycol amine, the content of diethylene glycol amine in the crude diethylene glycol amine is about 35%, and then sent to the separation and purification system.
Due to few side reactions, the purity of the refined diethylene glycolamine is ≥99%. The molar ratio of diethylene glycol, liquid ammonia and soft water is 1:5:5. The catalyst is a copper-nickel catalyst, and 0.003m3 of catalyst is required to produce 1 ton of diethylene glycol amine. During the catalytic ammoniation process, hydrogen does not participate in the reaction, and its role is to maintain system pressure. Compared with the prior art, the beneficial effects of the present invention are reflected in: the crude diethylene glycol amine prepared by the present invention has a high diethylene glycol amine content, a diethylene glycol conversion rate of more than 85%, and a diethylene glycol conversion rate of more than 85%. The yield of alcoholamine is over 70%; the equipment and catalysts are all domestically produced, enabling industrial production. Since there are few side reactions, the crude diethylene glycolamine prepared by the method of the present invention can be separated and purified to obtain a diethylene glycolamine product with a purity of more than 99%.
2. Synthesis of diethylene glycol monotert-butyl ether
Diethylene glycol monotert-butyl ether, also known as diethylene glycol monotert-butyl ether, or diethylene glycol monotert-butyl ether, is an important coating solvent and cleaning agent component. Diethylene glycol monotert-butyl ether has good low photochemical reactivity and is compatible with a variety of resins and solvents.It is miscible and has the dual advantages of low toxicity and low odor. It is widely used and selected in various fields such as coatings, inks, and cleaning agents.
CN201810771682.4 provides a synthesis method of diethylene glycol monotert-butyl ether. The method uses diethylene glycol and methyl tert-butyl ether to react under a catalyst to generate diethylene glycol monotert-butyl ether. A mixture of base ether, diethylene glycol di-tert-butyl ether and methanol, and the catalyst is zeolite, diatomite phosphate, heteropolyacid, strong acid ion exchange resin and/or molecular sieve.
Main reference materials
[1] Concise Dictionary of Fine Chemicals
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[2] Zhu Shanshan, Yang Leping, Gao Jianan, Xu Jiaming, Wang Qian, Zheng Lin. Health risk assessment of diethylene glycol in cosmetics [J]. Flavors and Fragrances Cosmetics, 2018(03):54-57.
[3]CN201410442739.8 A method for synthesizing diethylene glycol amine from diethylene glycol low-pressure method
[4]CN201810771682.4 Synthesis and production method of diethylene glycol monotert-butyl ether
