I found this an interesting read.
May have been posted before,so feel free to delete it if so.
PROCESS FOR PREPARING 3,4-DIOXO-SUBSTITUTED AROMATIC ALDEHYDES
http://v3.espacenet.com/publicationDetails/biblio?DB=EPODOC&adjacent=true&locale=en_gb&FT=D&date=20090305&CC=US&NR=2009062569A1&KC=A1
Example 1
[0029] 20.0 g (0.136 mols) of piperonyl alcohol, 200 g of toluene and 2.7 g (0.013 mols) of aluminium isopropoxide (homogeneous catalyst) are introduced into a 1000 ml flask. The solution is heated under reflux and 8.00 g (0.263 mols) of p-formaldehyde are slowly added. At the end of the addition the mixture is left for about 2 hours under reflux, after which it is cooled and 300 ml of an aqueous 1 M sodium hydroxide solution are added. The phases are separated and the organic solution evaporated under vacuum (at 30[deg.] C./21 mbar) to obtain a crude reaction product containing 3,4-methylenedioxybenzaldehyde with a GC yield of 99.3% and a conversion of 100%.
Example 7 (Comparative)
[0041] Operating as described in example 1, 10.8 g (0.1 mols) of benzyl alcohol are reacted, in 100 g toluene, with 6.0 g (0.29 mols) of p-formaldehyde in the presence of 2.04 g (0.01 mols) of aluminium protoxide.
[0042] After cooling and adding 300 ml of an aqueous 1 M sodium hydroxide solution, the phases are separated and the organic solution evaporated under vacuum (at 25[deg.] C./21 mbar) to obtain a crude reaction product containing benzaldehyde with a 73.6% GC yield and a conversion of 83.1%.
May have been posted before,so feel free to delete it if so.
PROCESS FOR PREPARING 3,4-DIOXO-SUBSTITUTED AROMATIC ALDEHYDES
http://v3.espacenet.com/publicationDetails/biblio?DB=EPODOC&adjacent=true&locale=en_gb&FT=D&date=20090305&CC=US&NR=2009062569A1&KC=A1
Example 1
[0029] 20.0 g (0.136 mols) of piperonyl alcohol, 200 g of toluene and 2.7 g (0.013 mols) of aluminium isopropoxide (homogeneous catalyst) are introduced into a 1000 ml flask. The solution is heated under reflux and 8.00 g (0.263 mols) of p-formaldehyde are slowly added. At the end of the addition the mixture is left for about 2 hours under reflux, after which it is cooled and 300 ml of an aqueous 1 M sodium hydroxide solution are added. The phases are separated and the organic solution evaporated under vacuum (at 30[deg.] C./21 mbar) to obtain a crude reaction product containing 3,4-methylenedioxybenzaldehyde with a GC yield of 99.3% and a conversion of 100%.
Example 7 (Comparative)
[0041] Operating as described in example 1, 10.8 g (0.1 mols) of benzyl alcohol are reacted, in 100 g toluene, with 6.0 g (0.29 mols) of p-formaldehyde in the presence of 2.04 g (0.01 mols) of aluminium protoxide.
[0042] After cooling and adding 300 ml of an aqueous 1 M sodium hydroxide solution, the phases are separated and the organic solution evaporated under vacuum (at 25[deg.] C./21 mbar) to obtain a crude reaction product containing benzaldehyde with a 73.6% GC yield and a conversion of 83.1%.