Abstract
Abstract Bronsted acidic ionic liquids composed of 1-butyl-3-methylimidazolium, triethylbutylammonium, and 1-butylpyridinium cation counterparts and HSO4‾ and H2PO4‾ anion counterparts were used as the catalysts for the selective chlorination of glycerol with hydrogen chloride to 3-chloro-1,2-propandiol. From the perspective of the glycerol conversion and product yields, the catalytic activities of the ionic liquids containing HSO4‾ were higher than the ionic liquids containing H2PO4‾. As compared with the carboxylic acid catalysts, Bronsted acidic ionic liquids favored the catalytic chlorination of glycerol to 3-chloro-1,2-propandiol. When the glycerol chlorination was catalyzed by the Bronsted acidic ionic liquids at 110 oC for 12 h with the catalyst loading of 0.75 mol·kg‾1 glycerol, the 3-chloro-1,2-propandiol yield was more than 81% at the complete conversion of glycerol.
Highlights
Biodiesel is an environmentally friendly and renewable fuel
When pyridine was mixed with nine Brønsted acidic ionic liquids, the adsorption peaks appearing at 1540 cm-1 were observed, indicating the presence of Brønsted acid sites in all the samples
Chlorination reaction catalyzed by Brønsted acidic ionic liquids
Summary
Biodiesel is an environmentally friendly and renewable fuel. With the rapid growth of biodiesel production, glycerol is produced as the main byproduct, ca. 10% of biodiesel, causing the glycerol market to be oversupplied (Katryniok et al, 2013; Tesser et al, 2007; Yi et al, 2014). With the rapid growth of biodiesel production, glycerol is produced as the main byproduct, ca. Researchers have paid great attention to the conversion of glycerol to high-valued chemicals, such as propanediol, propylene glycol, dichloropropanol, acrolein, and acrylic acid by hydrogenolysis (Dasari et al, 2005; Ma et al, 2008), catalytic chlorination (Santacesaria et al, 2010), dehydration (Shen et al, 2012), and oxydehydration. In the production of dichloropropanol via the chlorination of glycerol, 3-MCPD is produced first as an intermediate product, which can be rapidly chlorinated to dichloropropanol over carboxylic acid catalysts (de Araujo Filho et al, 2016; de Araujo Filho et al, 2016; Hou et al, 2015). Selective chlorination of glycerol to 3-MCPD with a high selectivity is worthy of investigation
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have