Acetaldehyde → Acetaldehyde

HRID 1667573Notes

Reaction equation

HRID 1667573 reaction equation
[CH:1](=[O:3])[CH3:2].[OH:4][CH2:5][CH:6]([CH2:8][OH:9])O>O>[OH:9][CH2:8][CH2:6][CH:5]=[O:4].[CH:1](=[O:3])[CH3:2].[CH2:1]=[O:3]

Participants

6

Reactant 2

HCID 177AcetaldehydeHCID 753Glycerol2×

Product 3

HCID 177AcetaldehydeHCID 712FormaldehydeHCID 75049Reuterin

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

It is known that acetaldehyde is obtained with a yield of 26% in the dehydration of glycerol in supercritical water at 500° C. and 34.5 MPa and with a residence time of 90 s [Ant1985]. A free radical mechanism by dehydration of the glycerol to 3-hydroxy-propionaldehyde and homolytic cleavage of this intermediate to give acetaldehyde and formaldehyde is assumed for the stated conditions. An alternative mechanism via homolytic cleavage of acetol can be ruled out. The selectivity with respect to acetaldehyde is lower under near-critical water conditions at 360° C. and the same conditions. Addition of sodium hydrogen sulphate as acidic catalyst merely leads to an increase in the yield of acrolein, which presumably results from the acid-catalysed dehydration of 3-hydroxypropionaldehyde.

Workup

  1. customwith a residence time of 90 s

Sources & evidence

ORD record
ord-4dc4be062ee248c3a98a804a4f84601a
Source dataset
uspto-grants-2011_10
Patent number
US08044246B2

Reaction notes

Loading…