Methoxy Propanol Solvent

Propylene glycol ethers are less toxic to the human body than ethylene glycol ether products and belong to low-toxicity ethers. Propylene glycol monomethyl ether has a faint ether smell but no strong irritating odor, making its application more extensive and safe. Propylene glycol monomethyl ether is an environmentally friendly organic solvent and is widely used in chemical production. It has strong solubility, low toxicity, and can be mixed with water and various organic solvents; it has strong coupling ability; low surface tension; low viscosity; and high evaporation rate. In the chemical production process such as coating preparation, paper chemical production, and paper surface treatment, a large amount of propylene glycol monomethyl ether waste liquid is generated. Studying the recovery of propylene glycol monomethyl ether is of great significance as it not only has considerable economic benefits but is also beneficial to environmental protection. The boiling point of propylene glycol monomethyl ether is between 118 and 119℃, which is very close to the boiling points of benzene and toluene. It can dissolve in water. Therefore, in the experimental process of recovering propylene glycol monomethyl ether, the effective separation of propylene glycol monomethyl ether from benzene and toluene is a difficult point. Xi Wei et al. from Chemicalbook used a co-boiling distillation technology. Under the condition of adding an appropriate amount of anhydrous ethanol as a co-boiling agent to the waste liquid, it can separate out the high-purity target product in a continuous and relatively stable distillation form. The conditions are as follows: (1) The distillation tower is controlled by an intermittent production process. The raw liquid is added to the bottom of the tower at one time to reduce unnecessary contact with pipelines and pollution. (2) Slow heating, with the steam pressure controlled at 0.3 to 0.4 MPa. (3) The low-boiling-point fractions at the top of the tower are collected for full reflux, with the reflux time set at 36 to 60 minutes. (4) After the top temperature of the tower stabilizes, the valve for the top distillate is opened, and the reflux ratio is controlled at 1:1 to 1:0.5, and the temperature is recorded. (5) If the top temperature is less than 110℃, the light components are separated; if it is between 110 and 115℃, it is regarded as a suspicious component, and samples are taken for analysis in two stages for confirmation. For the fractions above 115℃, they are regarded as genuine products, and one sample is taken for each increase of 1℃, to determine the final top temperature value based on actual testing.