Mechanistic study of a one-step catalytic conversion of fructose to 2,5-dimethyltetrahydrofuran.
Carbohydrates, such as fructose, can be fully dehydroxylated to 2,5-dimethyltetrahydrofuran (DMTHF), a valuable chemical and potential gasoline substitute, by the use of a dual catalytic system consisting of HI and RhX(3) (X=Cl, I). A mechanistic study has been carried out to understand the roles that both acid and metal play in the reaction. HI serves a two-fold purpose: HI acts as a dehydration agent (loss of 3 H(2)O) in the initial step of the reaction, and as a reducing agent for the conjugated carbinol group in a subsequent step. I(2) is formed in the reduction step and metal-catalyzed hydrogenation reforms HI. The rhodium catalyst, in addition to catalyzing the reaction of iodine with hydrogen, functions as a hydrogenation catalyst for C=O and C=C bonds. A general mechanistic scheme for the overall reaction is proposed based on identification of intermediates, independent reactions of the intermediates, and deuterium labeling studies.
Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA.
Matthew R
MR
Grochowski
Weiran
W
Yang
Ayusman
A
Sen
D002384:Catalysis; D003903:Deuterium / Q000737:chemistry*; D005632:Fructose / Q000737:chemistry*; D005663:Furans / Q000138:chemical synthesis* / Q000737:chemistry*; D006865:Hydrogenation; D015394:Molecular Structure; D012238:Rhodium / Q000737:chemistry
D005663:Furans; C051333:2,5-dimethyltetrahydrofuran; D005632:Fructose; D003903:Deuterium; D012238:Rhodium