Entry

Brønsted acid

(mol%)

Cobalt salt

Time/h

Yield/%

2

1

1

PhSO3H(10)

-

2

4.9

53.1

2

CH3SO3H(10)

-

2

0.0

47.9

3

CF3SO3H(10)

-

2

5.7

53.5

4

H3PO4(10)

-

2

0.0

58.8

5

H2SO4(10)

-

2

0.0

56.5

6

H2SO4(20)

-

2

3.3

56.1

7

CoCl2

2

0.0

83.4

8

-

Co(NO3)2∙6H2O

2

7.8

72.6

9

-

Co(ClO4)2∙6H2O

2

8.2

40.1

10

-

Co(BF4)2∙6H2O

2

10.3

32.0

11

PhSO3H(10)

CoCl2

2

47.7

40.3

12

PhSO3H(10)

Co(NO3)2∙6H2O

2

22.5

29.4

13

PhSO3H(10)

Co(ClO4)2∙6H2O

2

30.5

26.9

14

PhSO3H(10)

Co(BF4)2∙6H2O

2

64.9

26.8

15

PhSO3H(10)

Co(BF4)2∙6H2O

4

88.3

5.5

16

H3PO4(10)

Co(BF4)2∙6H2O

2

26.8

31.6

17

CF3SO3H(10)

Co(BF4)2∙6H2O

2

27.9

20.0

18

CH3SO3H(10)

Co(BF4)2∙6H2O

2

45.0

15.2

19

H2SO4(10)

Co(BF4)2∙6H2O

2

12.5

48.3

20

H2SO4(20)

Co(BF4)2∙6H2O

2

56.7

22.5

21

H2SO4(10)

Co(BF4)2∙6H2O

24

69.3

20.2

22

H2SO4(20)

Co(BF4)2∙6H2O

24

86.3

6.6