8 |
The obtained solution is cloudy. |
Inorganic salts (including Zn) may be present. |
Repeat Steps 7 and 8 using more sand; alternatively, use Celite® instead of sand. |
12 |
Water droplets are visible in the flask. |
Too much water is left in the product. |
Fix/obtain new vacuum pump; add toluene and repeat evaporation in vacuo. |
13/20 |
Excessively high yields of the desired crude salt. |
Too much water is left in the product. |
Fix/obtain new vacuum pump; add toluene and repeat evaporation in vacuo. |
13/20 /26 |
Low yields of the desired crude salt. |
Starting materials are not pure. |
Check the purity of the starting materials, repurify them if necessary. |
26 |
Elemental analysis shows %Cl of more than a few % for TFMS (1), DFMS (2) and TFES (3). |
ZnCl2 was not fully removed from the product. |
Repeat wash with 1:1 EtOAc:CH2Cl2. For TFES (3), the impure product can be sonicated in the presence of 1:1 EtOAc:CH2Cl2 to help remove more chloride. |