Hydroformylation of formaldehyde to glycolaldehyde (GA)

as a vital reaction in both direct and indirect process of syngas to ethylene glycol (EG)

shows great advantages in the aspects of the process complexity and clean production. The hydroformylation of formaldehyde to GA is thermodynamically unfavourable

requiring the development of highly efficient hydroformylation catalytic systems

appropriate reaction conditions and in-depth understanding of the reaction mechanisms. In this review

we have made a detailed summary on the reaction in terms of the reaction network

thermodynamics

metal complex catalysts (including central metals and ligands)

reaction conditions (

e.g.

temperature

pressure

formaldehyde source and solvent) and promoters. Furthermore

the reaction mechanisms

involving neutral and anionic complex in the catalytic cycle

have been summarized and followed by a discussion on the impact of the crucial intermediates on the reaction pathways and product distribution. A brief overview of product separation and catalyst recovery has been presented in the final part. This review gives new insights into the factors that impact on the formaldehyde hydroformylation and reaction mechanisms

which helps to design more effic

ient catalytic systems and reaction processes for EG production

via

the hydroformylation route.