Method for the production of aldehydes and ketones by oxidizing primary and secondary alcohols with alkylphosphonic acid anhydrides
View Patent ↗The invention relates to a method for the production of a.) aldehydes of formula (II): R 1 —CHO and b.) aldehydes of formula (III): R 1 —C(O)—R 2 by reacting a.) primary alcohols (R 1 CH 2 —OH) or b.) secondary alcohols (R 1 —CH(OH)—R 2 ) with cyclic phosphonic acid anhydrides in the presence of dialkyl-, diaryl- and/or alkyl-aryl sulphonic oxides at a temperature in the region of between −100 to +120° C., whereby R 1 and/or R 2 represent H, a substituted linear or branched C 1 -C 12 -alkyl radical, a substituted C 3 -C 10 cycloalkyl-, alkenyl-, aryl- or heteroaryl radical. A cyclic phosphonic acid anhydride is used, preferably, as a 2,4,6-substituted 1,3,5,2,4,6-trioxatriphosphinane of formula (I), wherein R′ independently represents allyl, aryl or open-chained or branched C 1 -C 12 -alkyl-radicals. Optionally, the reaction can be carried out in the presence of a tertiary amine base NR 5 3
1. A process for preparing a.) aldehydes of the formula (II) and b.) ketones of the formula (III)
R 1 —CHO (II)
R 1 —C(O)—R (III)
said process comprising reacting a reaction solution comprising a starting compound selected from
a.) primary alcohols (R 1 CH 2 —OH) or
b.) secondary alcohols (R 1 —CH(OH)—R 2 )
with cyclic phosphonic anhydrides in the presence of dialkyl sulfoxides, diaryl sulfoxides and/or alkyl aryl sulfoxides at a temperature in the range from −100 to +120° C.,
where R 1 and/or R 2 are each a substituted linear or branched C 1 -C 12 -alkyl radical, a substituted C 3 -C 10 -cycloalkyl, -alkenyl, -aryl or -heteroaryl radical.
2. The process as claimed in claim 1 , wherein the cyclic phosphonic anhydride is a 2,4,6-substituted 1,3,5,2,4,6-trioxatriphosphinane of the formula (I)
where R′ is independently allyl, aryl or open-chain or branched C 1 - to C 12 -alkyl radicals.
3. The process as claimed in claim 2 , wherein R′ is a methyl, ethyl, n-propyl, isopropyl, n-butyl, 2-butyl, isobutyl, pentyl, and/or hexyl, radical.
4. The process as claimed in claim 1 wherein the cyclic phosphonic anhydride is added to the reaction solution either as a melt or dissolved in a solvent.
5. The process as claimed in claim 4 , wherein the cyclic phosphonic anhydride is added in an aprotic solvent.
6. The process as claimed in claim 1 wherein the reaction solution is heated to the reaction temperature before the phosphonic anhydride is added.
7. The process as claimed in claim 1 wherein a sulfoxide of the formula (IV) is used
R 3 —S(O)—R 4 (IV)
where R 3 and R 4 are each independently allyl, aryl or open-chain, cyclic or branched C 1 - to C 12 -alkyl radicals, aryloxy, allyloxy or alkoxy having open-chain, cyclic or branched C 1 - to C 12 -alkyl radicals, or a combination of the substituents mentioned.
8. The process as claimed in claim 1 characterized in that wherein the reaction is carried out in the presence of an amine base of the formula (V)
NR 5 3 (V)
where R 5 is H, allyl, aryl or open-chain, cyclic or branched C 1 - to C 12 -alkyl radicals, aryloxy, allyloxy or alkoxy having open-chain, cyclic or branched C 1 - to C 12 -alkyl radicals, or a combination of the substituents mentioned.
9. The process as claimed in claim 1 wherein the phosphonic anhydride is used in from one third of the stoichiometric amount to a superstoichiometric amount in relation to the starting compound.
10. The process as claimed in claim 3 , wherein R′ is an ethyl, propyl and/or butyl radical.