Studies on catalytic hydrogenation of citral by water-soluble palladium complex

✍ Scribed by Kam-Chung Tin; Ning-Bew Wong; Rui-Xiang Li; Yao-Zhong Li; Xian-Jun Li

• Book ID: 104424010
• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 78 KB
• Volume: 137
• Category: Article
• ISSN: 1381-1169
• DOI: 10.1016/s1381-1169(98)00111-3

✦ Synopsis

The hydrogenation of citral has been studied in biphasic system using water-soluble PdCl TPPTS as catalyst. The 2 2 selectivity to form citronellal increased with increasing pH values of the aqueous phase. At the same pH value, the selectivity was higher when the hydrogenation was carried out in the presence of Na CO than in the presence of NaOH.

2 3

The main product was citronellal and a maximum yield of 93% had been obtained using Na CO solution at pH 11.6. The 2 3

C5C bond in citronellal could be further hydrogenated to form dihydrocitronellal when the hydrogenation was carried out in distilled water at pH 6.0. The yield of dihydrocitronellal could reach 93% with prolonged reaction time to 6 h. Therefore, high yields of either citronellal or dihydrocitronellal could be obtained from citral by selecting the corresponding reaction conditions.