Direct Catalytic Methanol-to-Ethanol Photo-conversion via Methyl Carbene

doi:10.1016/j.chempr.2019.01.005

Chem

Volume 5, Issue 4, 11 April 2019, Pages 858-867

https://doi.org/10.1016/j.chempr.2019.01.005 Get rights and content

Under an Elsevier user license

open archive

Highlights

•
Transformation of a hazardous fuel into a safer and more useful renewable fuel
•
Generation of the versatile reaction intermediate methyl carbene from methanol
•
One-step conversion using only light and no other additive
•
Carbon chain elongation could enable conversions to materials such as plastic (PE)

The Bigger Picture

Methanol is an easily accessible fossil fuel alternative, but it is classified as hazardous and is also generally less valuable than other sources of carbon. A direct conversion of methanol to ethanol would provide facile access to a renewable starting material for applications as a safer fuel or an intermediate for the synthesis of the most demanded plastic, polyethylene (PE). This article reports the chemical transformation of methanol to ethanol and other higher alcohols, enabled by sp³-C–H methylation. In addition, the underlying chemistry can also be of importance for biochemistry and pharmaceutical chemistry, where methylation plays a pivotal role. The methanol-to-ethanol conversion is achieved in the presence of a robust catalyst and in only one step. No additive, solvent, or hazardous material is required.

Summary

As an important effort to secure the sustainable “fossil alternative,” the direct conversion of the more readily available methanol to the more user-friendly, less toxic, and broadly applicable ethanol poses exciting potential as well as a tremendous scientific challenge. Herein, we report the first photo-driven one-step conversion of methanol to ethanol at ambient temperature, catalyzed by an ultra-stable gallium nitride semiconductor. Mechanistic studies revealed that methyl carbene (methylene), one of the most fascinating C₁ building blocks in synthetic chemistry, was generated as a reaction intermediate, which potentially enables a green and novel method for generating carbene. We also found that methanol can be converted to n-propyl alcohol with the same catalyst through a simple change in reaction temperature, giving a unique selectivity and a high-value-added product.

Graphical Abstract

UN Sustainable Development Goals

SDG7: Affordable and clean energy

SDG11: Sustainable cities and communities

Keywords

advanced materials

semiconductor

methanol to ethanol

photo-conversion

carbene

Cited by (0)

⁵: These authors contributed equally

⁶: Lead Contact