METHOD FOR PREPARING GLYCOLIC ACID
Provided is a method for preparing glycolic acid which comprises oxidizing glycolaldehyde with molecular oxygen in the presence of a solvent and a supported catalyst. Said supported catalyst comprises (i) a noble metal selected from the group consisting of Pt, Pd, Ru and Rh, (ii) Bi and (iii) a support. Advantageously, the supported metallic catalyst is more active than the catalysts used in prior art. Furthermore, the catalyst is more stable at oxygen rich conditions.
1 . A method for preparing glycolic acid comprising oxidizing glycolaldehyde with molecular oxygen in the presence of a solvent and a supported catalyst comprising (i) a noble metal selected from the group consisting of Pt, Pd, Ru and Rh, (ii) Bi and (iii) a support.
2 . The method according to claim 1 , wherein the weight ratio of Bi to the noble metal in the supported catalyst ranges from 0.03 to 1.
3 . The method according to claim 2 , wherein the weight ratio of Bi to the noble metal in the supported catalyst ranges from 0.2 to 0.3.
4 . The method according to claim 1 , wherein the loading of the noble metal ranges from 1 to 10 wt. % based on total weight of catalyst.
5 . The method according to claim 4 , wherein the loading of the noble metal ranges from 3 to 5 wt. % based on total weight of catalyst.
6 . The method according to claim 1 , wherein the weight ratio of the supported catalyst to glycolaldehyde is from 5 to 50%.
7 . The method according to claim 6 , wherein the weight ratio of the supported catalyst to glycolaldehyde is from 5 to 10%.
8 . The method according to claim 1 , wherein the noble metal is Pt.
9 . The method according to claim 1 , wherein the support is carbon or aluminum oxide.
10 . The method according to claim 1 , wherein molecular oxygen is supplied in the form of oxygen gas or air.
11 . The method according to claim 10 , wherein molecular oxygen is supplied in the form of oxygen gas having a purity of at least 99%.
12 . A mixture comprising glycolaldehyde, molecular oxygen, a solvent and a supported catalyst comprising (i) a noble metal selected from the group consisting of Pt, Pd, Ru and Rh, (ii) Bi and (iii) a support.
13 . The mixture according to claim 12 , wherein molecular oxygen is in the form of oxygen gas having a purity of at least 99%.
14 . The mixture according to claim 12 , wherein the solvent is water.
15 . The mixture according to claim 12 , wherein the noble metal is Pt.
16 . The mixture according to claim 12 , wherein the support is carbon.