Production of Monoethylene Glycol from Lignocellulosic Biomass via Catalytic Hydrogenation: A Review

Abstract

Ethane and ethanol are produced through steam cracking and fermentation into ethylene respectively, which is then hydrolysed into monoethylene glycol (MEG). The disadvantages of both processes included used of easily oxidized substance and large quantities of water in order to minimize by-products such as diethylene glycol and triethylene glycol. Apart from that, MEG can also be produced by catalytic hydrogenation of biomass at extreme temperature and pressure with presence of catalyst. At the same time, this process uses lignocellulosic waste that have a high cellulose content such as residues from the agricultural and food industries. However, lignocellulosic biomass has to be treated to remove lignin content that may lower the rate of hydrogenation activity. In addition, most studies have found that the temperature in range of 240 °C to 280 °C and pressure of 5 MPa to 6 MPa are able to produce 18 wt% to 64 wt% of MEG. Meanwhile, the catalyst that have attract the researchers’ attention are nickel and tungsten species which are able to increase the MEG yield by overcoming the activation energy of the hydrogenation process. Factors such as lignocellulose’s pre-treatment, operating temperature and pressure, and the presence of catalyst will be discussed further.