Towards inhibition of yellowing of mechanical pulps .1. Catalytic hydrogenation of lignin model compounds under mild conditions
Hu, TQ; James, BR; Lee, CL
| HERO ID | 7733010 |
|---|---|
| In Press | No |
| Year | 1997 |
| Title | Towards inhibition of yellowing of mechanical pulps .1. Catalytic hydrogenation of lignin model compounds under mild conditions |
| Authors | Hu, TQ; James, BR; Lee, CL |
| Journal | Journal of Pulp & Paper Science |
| Volume | 23 |
| Issue | 4 |
| Page Numbers | J153-J156 |
| Abstract | Di-μ-chloro-bis(η4-1, 5-hexadiene)-dirhodium(I) effectively catalyzed the hydrogenation of the aromatic rings of the lignin model compounds 4-propylphenol, eugenol, 1,2-dimethoxy-4-propylbenzene and 2,6-dimethoxy-4-propyl-phenol under extremely mild conditions (25°C, 1 Mm H2) in a two-phase, hexane/aqueous pH 7.5 medium. This catalyst was more active than di-μ-chloro-bis (η4-1,5-cyclooctadiene)-dirhodium(I), rhodium(III) trichloride trihydrate and ruthenium(III) trichloride trihydrate. The reactivity of three predominant functional groups in lignin toward the rhodium(I) catalyzed hydrogenation followed the descending order of carbon-carbon double bond > aromatic ring > carbonyl group. The hydrogenation reactions were sensitive to steric and electronic effects of the substituent(s) on the aromatic rings. Moderate to extremely high diastereoselectivities were observed for the hydrogenated products. |
| Wosid | WOS:A1997WU94700002 |
| Is Certified Translation | No |
| Dupe Override | No |
| Comments | Scopus URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-0031122047&partnerID=40&md5=144343ac94a8adba81dc42f187edd2d0 |
| Is Public | Yes |
| Language Text | English |
| Keyword | inhibition; yellowing; mechanical pulps; hydrogenation; catalysts; lignin model compounds; aromatic groups; carbonyl groups; chromophores; eugenol; hydrogenolysis; quinones |