Critical Assessment of Reaction Pathways for Next-Generation Biofuels from Renewable Resources: 5-Ethoxymethylfurfural

Abstract

Renewable resources must be upgraded to platform chemicals and biofuels, especially furanic compounds such as 5-hydroxymethylfurfural (5-HMF) and 5-ethoxymethylfurfural (5-EMF), to meet the needs of a sustainable society. This review examines chemocatalytic approaches to 5-EMF via alcoholysis of 5-(halomethyl)furfural or etherification of 5-HMF with attention being given to direct catalytic conversion of biomass-derived materials into 5-EMF. Emphasis is placed on the reaction mechanisms and pathways with either homogeneous or heterogeneous catalysts to provide recommendations for catalytic system development. A multicriteria assessment evaluation tool as a sustainability assessment method for the synthesis of 5-EMF routes from biomass is given. Potential research directions include the direct synthesis of 5-EMF from biomass-derived compounds in innovative reaction systems and technoeconomic studies on 5-EMF production.

One-pot tandem synthesis of 5-ethoxymethylfurfural as a potential biofuel

“…14 As already mentioned, EMF is considered to possess adequate properties and great potential to be used as a biofuel or additive for gasoline and diesel in the fuel industry. 12,14,15 This is mainly because it has a high energy density, which was previously estimated to be 30.3 MJ L −1 . This value is higher than that of ethanol (23.5 MJ L −1 ) and similar to gasoline (31.1 MJ L −1 ) and diesel (33.6 MJ L −1 ).…”

“…9 EMF has gained increasing attention as a potential biofuel and fuel additive. 10,11 However, it has also been reported to have valuable applications in other areas, 12 such as in the food industry as a flavor and aroma additive in beverages such as wine and beer 13 and as a reaction substrate for the synthesis of various industrially interesting chemicals, such as ethyl levulinate, 2,5-diethoxymethylfuran, 5-ethoxymethylfurfuryl alcohol and cyclopentenone. 14 As already mentioned, EMF is considered to possess adequate properties and great potential to be used as a biofuel or additive for gasoline and diesel in the fuel industry.…”

Catalytic Transfer Hydrogenation and Ethanolysis of Furfural to Ethyl Levulinate Using Sulfonated Hf- or Ni-Catalysts Prepared with Mixed Solvents

“…7,8 One-pot, two-step conversion of carbohydrates into EL with a mixture of Lewis acid (L) and Brønsted acid (B) catalysts has been reported. 8,9 However, synthesis procedures for bifunctional catalysts that contain both Lewis acid sites (L) and Brønsted acid sites (B) tend to be time consuming and tedious. 10 In this work, the catalyst was designed not only for promoting transfer hydrogenation to convert furfural into FAL but also for promoting ethanolysis of FAL into EL.…”

“…6−8 However, one-pot synthesis of EL requires a bifunctional catalyst that can promote hydrogenation of furfural to FAL and ethanolysis of formic acid (FA) into EL. 7,8 One-pot, two-step conversion of carbohydrates into EL with a mixture of Lewis acid (L) and Brønsted acid (B) catalysts has been reported. 8,9 However, synthesis procedures for bifunctional catalysts that contain both Lewis acid sites (L) and Brønsted acid sites (B) tend to be time consuming and tedious.…”

“…Generally, EL can be obtained from levulinic acid (LA) by acid catalysis in ethanol, whereas considering the high cost of LA, commercial production of EL by acid catalysis of C5 carbohydrates [e.g., furfuryl alcohol (FAL)] , or C6 carbohydrates (e.g., fructose) via LA as an intermediate would be desirable. − However, one-pot synthesis of EL requires a bifunctional catalyst that can promote hydrogenation of furfural to FAL and ethanolysis of formic acid (FA) into EL. , One-pot, two-step conversion of carbohydrates into EL with a mixture of Lewis acid (L) and Brønsted acid (B) catalysts has been reported. , However, synthesis procedures for bifunctional catalysts that contain both Lewis acid sites (L) and Brønsted acid sites (B) tend to be time consuming and tedious . In this work, the catalyst was designed not only for promoting transfer hydrogenation to convert furfural into FAL but also for promoting ethanolysis of FAL into EL.…”