Synthesis method of ethylene glycol butyl ether_industrial additives

Background technology

Ethylene glycol butyl ether (HOCH2CH2OCH2CH2CH2CH3) is a colorless flammable liquid with a moderate ether smell and a boiling point of 171°C. Because its molecule contains both ether bonds and hydroxyl groups, this unique property allows it to dissolve organic molecules, synthetic or natural polymer compounds, and is miscible with water or water-soluble compounds to varying degrees. Therefore, it is widely used Used as coatings, inks, cleaning agents, pharmaceutical extractants, etc. According to statistics, my country’s coating and ink industry consumed approximately 200,000 tons of glycol ether in 2010, accounting for approximately 80% of the total consumption of glycol ether. The cleaning agent industry consumes approximately 20,000 tons of glycol ethers, accounting for approximately 8% of the total consumption of glycol ethers. It can be seen that solvents for coatings are still the largest application field of glycol ethers. However, recent studies have shown that glycol ethers (especially methyl ether and ethyl ether) may cause blood diseases and fetal malformations, and developed countries have begun to partially restrict their production and use. However, ethylene glycol butyl ether does not show similar toxicity, and it is not transported and stored as dangerous goods abroad. Therefore, it is imperative to use ethylene glycol butyl ether in solvents instead of ethylene glycol methyl ether and diethyl ether. At present, ethylene glycol butyl ether is the largest consumer in my country, accounting for approximately 60% of the total consumption of ethylene glycol ether products. However, due to the immaturity of domestic production technology for ethylene glycol butyl ether, my country’s source of ethylene glycol butyl ether mainly relies on imports, with imports accounting for more than 90% of the total. In recent years, my country’s production of ethylene glycol butyl ether Demand is growing at an average annual growth rate of 10%, and the imbalance between supply and demand is becoming increasingly serious. Therefore, it is particularly important to open up a feasible production route for Japanese Kao ethylene glycol butyl ether.

Synthesis method

According to the literature and patents, it can be seen that there are two main ways to synthesize ethylene glycol butyl ether:

1. Using ethylene oxide Use alkane and butanol as raw materials to prepare ethylene glycol butyl ether

+ CH3CH2CH2CH2OH→HOCH2CH2OCH2CH2CH2CH3……………………….. (1)

As shown in equation (1), Zhang Mu used this reaction pathway to prepare ethylene glycol butyl ether in the 2008 volume 37 supplement of “Petrochemical Industry”. This method uses ethylene oxide and n-butanol as raw materials and heteropoly acid as a catalyst to prepare ethylene glycol butyl ether at 70 to 120°C under low pressure. The selectivity of the product ethylene glycol butyl ether is up to 75%. However, this reaction has many by-products and is a strongly exothermic reaction. The reaction is not easy to control. The product contains a large amount of diethylene glycol butyl ether, triethylene glycol butyl ether, tetraethylene glycol butyl ether, and pentaethylene glycol butyl ether. Ether, hexaethylene glycol butyl ether and the corresponding double ether are difficult to separate later, and the energy consumption of n75 curing agent is high.

2. Production of ethylene glycol butyl ether by synthesis gas formaldehyde method

CO+2H2+HCHO+CH3CH2CH2CH2OH→HOCH2CH2OCH2CH2CH2CH3+H2O….(2)

As shown in equation (2), Japanese chemist Kurashiki introduced in United States Patent 4071568 that synthesis gas, formaldehyde and n-butanol are used as raw materials, and cobalt is used as a catalyst under extremely high pressure conditions of 100 to 250 ℃ and 50Mpa. Ethylene glycol butyl ether, among which the highest yield of ethylene glycol butyl ether is 55.6%. However, the disadvantage of this method is that the reaction needs to be carried out under extremely high pressure, requiring 500 atmospheres, which requires extremely high requirements for reaction equipment. Moreover, the preparation process of the cobalt catalyst for the reaction is cumbersome and cannot be reused, so it is not suitable for large-scale industrial production.

3. Reaction of ethylene glycol and butanol to produce ethylene glycol butyl ether

HOCH2CH2OH+CH3CH2CH2CH2OH→HOCH2CH2OCH2CH2CH2CH3………… ..(3)

As shown in equation (3), ethylene glycol and butanol are used as reaction raw materials to prepare ethylene glycol butyl ether under acid catalyzed conditions. This method is currently the most common industrial method for ethylene glycol butyl ether. Preparation method of alcohol butyl ether. However, the reaction products are complex, including ethylene glycol dibutyl ether, butyl ether, diethanol butyl ether, diethylene glycol dibutyl ether, etc., making subsequent separation difficult and requiring high energy consumption.

Based on the above reasons, we have developed a new synthesis route for ethylene glycol butyl ether. The first step is to synthesize butoxymethoxymethane with high selectivity from methylal and butanol; The second step is directional carbonylation of butoxymethoxymethane to generate butoxymethyl acetate; the third step is hydrogenation of butoxymethyl acetate to generate ethylene glycol butyl ether and methanol. The third step of the ester hydrogenation reaction is very easy to carry out and has high selectivity. In the second step of the directional carbonylation reaction, the highly selective carbonylation of methylal to produce methyl methoxyacetate has been reported in literature and patents. Only for the synthesis of methoxybutoxymethane, the raw material for the first step of the reaction, there are currently no reports on specific synthesis methods and pathways on SciFinder.