Purification of an aromatic fraction containing acetylenes by selective hydrogenation of the acetylenes
View Patent ↗A process for purification of an aromatic fraction containing acetylenes as impurities by selective hydrogenation of the acetylenes by means of a catalyst containing nickel or palladium at a temperature of not more than about 60° C. is described.
1. A process for purification of an aromatic fraction containing less than about 20% by weight of acetylenes as impurities by selective hydrogenation of the acetylenes, wherein the acetylene triple bonds are hydrogenated to single bonds by means of a catalyst containing nickel or palladium at a temperature of not more than about 60° C., wherein the product obtained after selective hydrogenation contains less than 0.35% by weight of acetylenes and olefins.
2. The process according to claim 1 , wherein the aromatic fraction comprises at least about 5% by weight of aromatic hydrocarbons.
3. The process according to claim 1 , wherein the aromatic fraction comprises one or more aromatic hydrocarbons selected from the group consisting of benzene, toluene and xylene.
4. The process according to claim 1 , wherein the hydrogenation temperature is less than about 55° C.
5. The process according to claim 1 , wherein the acetylenes comprise one or more acetylenes selected from the group consisting of substituted acetylenes, diacetylene and substituted diacetylenes.
6. The process according to claim 1 , wherein the aromatic fraction is a by-product or is based on a by-product of acetylene production by means of a cracking process.
7. The process according to claim 1 , wherein the catalyst comprises nickel.
8. The process according to claim 1 , wherein the catalyst comprises at least one of Raney nickel, Ni supported on alumina, Pd supported on alumina and Pd supported on activated carbon.
9. The process according to claim 8 , wherein the amount of catalyst is about 0.01 to about 10% by weight, based on the total weight of the aromatic fraction in the reaction volume.
10. The process according to claim 1 , wherein the hydrogen pressure is not more than about 50 bar.
11. The process according to claim 1 , wherein the reaction time of the hydrogenation is not more than about 120 min.
12. The process according to claim 1 , wherein the aromatic fraction comprises a solvent.
13. The process according claim 1 , wherein a solvent is added to an aromatic fraction obtained from a separation process before hydrogenation.
14. The process according to claim 12 or claim 13 , wherein the solvent is selected from the group consisting of hydrocarbons, water, ethanol, methanol, methanol/water and mixtures thereof.
15. The process according claim 1 , wherein the catalytic hydrogenation is carried out in a fixed bed reactor or in suspension.
16. The process according to claim 1 , wherein the aromatic fraction comprises at least about 10% by weight of aromatic hydrocarbons.
17. The process according to claim 12 , wherein the aromatic fraction comprises an alkanol or an alkanol/water mixture.