Process for preparing glycolide
According to the present invention a process is provided for producing glycolide which comprises contacting glycolaldehyde dimer with an oxidizing agent to produce a glycolide product. Preferably, the process is carried out in an aprotic environment, such as in a reaction mixture comprising the glycolaldehyde dimer, the oxidizing agent, the glycolide product and an aprotic solvent.
1. A process for producing glycolide comprising an oxidation step of contacting glycolaldehyde dimer with an oxidizing agent to produce a glycolide product, wherein the oxidation step is carried out in an aprotic solvent.
2. The process according to claim 1 , wherein the oxidation step is carried out in a reaction mixture comprising the glycolaldehyde dimer, the oxidizing agent, the glycolide product and the aprotic solvent.
3. The process according to claim 1 , wherein the aprotic solvent makes up at least 70 wt % of the reaction mixture.
4. The process according to claim 1 , wherein the aprotic solvent is an oxo-compound.
5. The process according to claim 1 , wherein the aprotic solvent is selected from the group consisting of N-methylpyrrolidone, dichloromethane, tetrahydrofuran (THF), ethyl acetate (EtOAc), acetone, methyl ethyl ketone, methyl isobutyl ketone, N, N-dimethylformamide (DMF), acetonitrile (MeCN), dimethyl sulfoxide (DMSO), propylene carbonate (PC), dioxane, and cyclohexanone; or mixtures thereof.
6. The process according to claim 1 , wherein the glycolaldehyde dimer is biobased.
7. The process according to claim 1 , wherein the oxidizing agent is selected from the group consisting of Dess-Martin periodinane, peracetic acid, oxygen, hydrogen peroxide, Oppenauer oxidation catalyst, metallo silicates, Shvo's catalyst, and aluminum isopropoxide; or mixtures thereof.
8. The process according to claim 1 , wherein the oxidation step is conducted at a temperature in the range of from 0-100 ° C.
9. The process according to claim 1 , wherein the oxidation step is conducted as a continuous process.
10. The process according to claim 2 , wherein the reaction mixture has a pH which is kept in the range of from 6 to 8.
11. The process according to claim 1 , wherein the glycolide is recovered.