Here the problem is quite easier to solve with COCl2 as gaseous. If using concentrated amonia/water(may be 25%) then when neutralizing phosgen you'll obtain probably urea (carbamid) as product this reaction. With NaOH just NaCl and NaHCO3.. By my opinion conc. amonia will work nice too also phosgene may react with NH3 at gaseous phase too ;)But the classic is 5-10% NaOH