Bio-hydrocarbon production from sorbitol

Abstract

The use of fossil fuels in transportation and power generation machinery cause global warming and petroleum reserve decrease, so we need hydrocarbon fuels from biomass. Biomass is converted into polyol and polyol is converted into bio-hydrocarbon. Sorbitol is polyol with six carbons which makes easier to produce bio-hydrocarbon and the yield increases. On laboratory-scale(1990s), sorbitol can produce bio-hydrocarbon by 2 steps, which are conversion sorbitol into iodohexane(the first) and conversion iodohexane into bio-hydrocarbon(the second). The first step using HI (making iodide ion oxidized to iodine) and H 3 PO 3 . Iodine regeneration into HI using H 3 PO 3 produces H 3 PO 4 , which is difficult to be reduced back to H 3 PO 3 . It is an expensive process, so it needs modification by using HCOOH. In order that the need for HI in system is small, HI regeneration reaction is expected not slower than sorbitol reduction reaction by HI, so it requires CuI catalyst. The second step done by heating using KOH-ethanol. Referring to the previous description, the purpose of this study is to investigate the bio-hydrocarbon production from sorbitol using HI for sorbitol conversion, HCOOH for iodine regeneration, and CuI as catalyst to accelerate HI regeneration reaction. Mixture (sorbitol, HI, HCOOH and CuI) in three-neck flask and refluxed at 90°C for 4, 6, 8, 10 and 12h. The molar ratios of Sorbitol:HI are 1:2 and 1:6. The molar ratios of sorbitol:HCOOH are 1:8 and 1:16. Sorbitol conversion determined by titration method, iodohexane yield determined by gravimetric method and product identification uses GC-MS. Bio-hydrocarbon(C 6 H 12 ) can be produced from sorbitol under relatively mild condition. The longer reaction time, the more HI, HCOOH and CuI are used, it gives more sorbitol conversion, iodohexane and bio-hydrocarbon(C 6 H 12 ) yield. Maximum sorbitol conversion is 96.3%, maximum iodohexane yield is 84.3% and maximum bio-hydrocarbon (C 6 H 12 ) yield is 84.3% at 90° 12h reaction time, molar ratio of sorbitol/HI/HCOOH is 1:6:16 and use CuI catalyst.