[kamiyu]

hi there

I understand that chloroform produces phosgene and thus HCl when it gets oxidized by air. And I think it is very important to ensure that the deuteriated chloroform does not contain any HCl for accurate NMR.

Could you please offer some ways to minimize the generation of HCl??

I understand that commercial chloroform (solvent) is stabilized by EtOH (or amyl alcohol) but this is not an option for CDCl3.

[TheUnassuming]

Every CDCl3 bottle I open I put in some K2CO3 (flame dried under vacuum) to soak up any trace DCl and some mol sieves to soak up any water that might get in during the life of that bottle.  In theory since the mol sieves are basic, you shouldn't need the K2CO3 but our lab always buys 100ml bottles so its better to be careful. 
The DCl produced won't hurt your NMR's as long as your compound is acid stable. 

[Benzene]

Is this really a concern at room temperature? The chloroform I have contains water...

[PhDoc]

If you are really concerned about acidity, then the best practice is to run your CDCl3 through a "pipette column" of activated basic alumina just before use. When completing my graduate research, I was working with mixed acetals that decomposed in the presence of trace acid. This was the only trick that took care of the DCl and water simultaneously, albeit the CDCl3 was stored over molecular sieves.