Thermodynamic equilibrium analysis on the dehydration of glycerol with monohydric alcohols to alkyl glyceryl ethers

Abstract

Under the conditions of the feed of 400 moles of alcohol + 100 moles of glycerol, 313-573 K and 0.1 MPa, based on Gibbs free energy global minimization, an improved genetic algorithm was used for the thermodynamic equilibrium analysis on the synthesis processes of alkyl glyceryl ethers, respectively, from methanol + glycerol, ethanol + glycerol, isobutanol + glycerol, and tert-butanol + glycerol. The columnar stacking charts and three-dimensional contour graphs were used to compare the effects of temperature, pressure, and the feed ratio to the equilibrium conversion, product selectivity, and equilibrium composition. The basic laws of the synthesis processes of alkyl glycerol ethers in homogeneous and heterogeneous states were investigated in a wide temperature range. Through comparison, it was found that the isopropanol + glycerol system is easier to convert into alkyl glycerol ethers, followed by the ethanol + glycerol system. The methanol + glycerol system and tert-butanol + glycerol system are greatly affected by pressure and temperature, and their conversions and selectivities are relatively low.

Sustainable Synthesis of Epoxides from Halohydrin Cyclization by Composite Solid-Based Catalysts

“…Epoxides are important raw materials in the chemical industry for the synthesis of glycols, epoxy resins, polyethers, etc. − They are commonly synthesized through the oxidation of olefins by molecular oxygen or peroxides in the presence of metal catalysts. Epoxides can also be synthesized through the dehydrohalogenation of halohydrins through base-driven S N 2 substitution. − However, due to the general consensus of pursuing a sustainable green process, new methods are continuously developed to replace the petrochemical-based routes. − Glycerol, an oversupplied byproduct from biodiesel production, − has therefore been considered as an alternative feedstock for the production of epoxides. − The simplest route to achieve the set target would start with the halogenation of one of the hydroxyl groups to form chloro-propanediol under the presence of an organic acid catalyst such as acetic acid. Then, the base-driven S N 2 substitution can be applied to carry out the ring-closing epoxidation.…”