Hydroformylation of formaldehyde to glycolaldehyde:An alternative synthetic route for ethylene glycol

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 efficient catalytic systems and reaction processes for EG production via the hydroformylation route.

Reactive carbonyl compounds(RCCs) cause aggregation and dysfunction of fibrinogen

Fibrinogen is a key protein involved in coagulation and its deposition on blood vessel walls plays an important role in the pathology of atherosclerosis.Although the causes of fibrinogen(fibrin)deposition have been studied in depth,little is known about the relationship between fibrinogen deposition and reactive carbonyl compounds(RCCs),compounds which are produced and released into the blood and react with plasma protein especially under conditions of oxidative stress and inflammation.Here,we investigated the effect of glycolaldehyde on the activity and deposition of fibrinogen compared with the common RCCs acrolein,methylglyoxal,glyoxal and malondialdehyde.At the same concentration(1 mmol/L),glycolaldehyde and acrolein had a stronger suppressive effect on fibrinogen activation than the other three RCCs.Fibrinogen aggregated when it was respectively incubated with glycolaldehyde and the other RCCs,as demonstrated by SDS-PAGE,electron microscopy and intrinsic fluorescence intensity measurements.Staining with Congo Red showed that glycolaldehyde-and acrolein-fibrinogen distinctly formed amyloid-like aggregations.Furthermore,the five RCCs,particularly glycolaldehyde and acrolein,delayed human plasma coagulation.Only glycolaldehyde showed a markedly suppressive effect on fibrinogenesis,none did the other four RCCs when their physiological blood concentrations were employyed,respectively.Taken together,it is glycolaldehyde that suppresses fibrinogenesis and induces protein aggregation most effectively,suggesting a putative pathological process for fibrinogen(fibrin)deposition in the blood.