Hi all. I am not sure how I would derive this measurement for my lab. My ochem lab is asking for 'a twofold excess of thionyl chloride.' Not sure what this means. Physical constants I have for thionyl chloride are its MW= 119 g/mol and d= 1.64 g/mL. The other reagent I will put into an RBFalong with the thionyl chloride is 0.4g of m-toluic acid.

 

Do I incorporate 0.4g into my calculation for the excess thionyl chloride? Thanks!

 

 

I would guess, if the ratio of thionyl chloride to m-toluic acid is 1:1, then you instead use 2 thionyl chloride.

In short, use twice as much as you should stoichiometrically.

Yes you were right.

 

This was the calculation that I eventually used:

 

0.4g X 1 mol/137g X 2 mol/1mol X 119g/mol X 1mL/1.64

 

 

In short I made the intermediate acid chloride first then made N,N-diethyl-m-toluamide afterwards. I almost forgot to follow up to this post until I began to assemble my lab report this morning. Just wanted to say thanks! Have a good day