Freezing pt depression deg C aqueous soln        
%wt    1-propanol    2-propanol
1    0.3    0.3
2    0.6    0.6
3    0.9    0.9
4    1.2    1.3
5    1.6    1.6
6    1.9    2
7    2.3    2.3
8    2.6    2.7
9    3    3.1
10    3.4    3.5
12    3.5    4.4
14    4.9    5.3
16    5.8    6.4
18    6.7    7.4
20    7.6    8.5
24    9.1    10.9
28    10.2    
32    10.7    

Don't ask me why the table stops where it does, I guess the solution separates into two liquid phases, but I don't know.

This is from the CRC handbook to Chemistry and Physics, so the wiggles in the curves should be authoritative.

Cheers

Greg Locock