Preparation of a carbon-based solid acid catalyst by sulfonating activated carbon in a chemical reduction process.
Sulfonated (SO(3)H-bearing) activated carbon (AC-SO(3)H) was synthesized by an aryl diazonium salt reduction process. The obtained material had a SO(3)H density of 0.64 mmol·g-1 and a specific surface area of 602 m2·g-1. The catalytic properties of AC-SO(3)H were compared with that of two commercial solid acid catalysts, Nafion NR50 and Amberlyst-15. In a 10-h esterification reaction of acetic acid with ethanol, the acid conversion with AC-SO(3)H (78%) was lower than that of Amberlyst-15 (86%), which could be attributed to the fact that the SO(3)H density of the sulfonated carbon was lower than that of Amberlyst-15 (4.60 mmol·g-1). However, AC-SO(3)H exhibited comparable and even much higher catalytic activities than the commercial catalysts in the esterification of aliphatic acids with longer carbon chains such as hexanoic acid and decanoic acid, which may be due to the large specific surface area and mesoporous structures of the activated carbon. The disadvantage of AC-SO(3)H is the leaching of SO(3)H group during the reactions.
Liu
Xiao-Yan
XY
College of Science, Northwest A&F University, Yangling 712100, Shaanxi, China.
Huang
Miao
M
Ma
Hai-Long
HL
Zhang
Zeng-Qiang
ZQ
Gao
Jin-Ming
JM
Zhu
Yu-Lei
YL
Han
Xiao-Jin
XJ
Guo
Xiang-Yun
XY
D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D010084:Oxidation-Reduction; D013343:Styrenes / Q000737:chemistry; D013451:Sulfonic Acids / Q000737:chemistry*; D014961:X-Ray Diffraction
D013343:Styrenes; D013451:Sulfonic Acids; C528218:amberlyst-15; D002244:Carbon