Catalyst type

number

Clarification time (min)

Yield (%)

p-toluenesulfonic acid

1

112

80.9

Concentrated sulfuric acid

2

151

78.6

p-toluenesulfonicacid+Phosphorous acid

3

105

94.8

Concentrated sulfuric acid+Phosphorous acid

4

122

92.4

p-toluenesulfonicacid+concentrated sulfuric acid

5

115

89.2